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Sample records for multiple pathogen strains

  1. Comparative genomic analysis of multiple strains of two unusual plant pathogens: Pseudomonas corrugata and Pseudomonas mediterranea

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    Emmanouil A Trantas

    2015-08-01

    Full Text Available The non-fluorescent pseudomonads, Pseudomonas corrugata (Pcor and P. mediterranea (Pmed, are closely related species that cause pith necrosis, a disease of tomato that causes severe crop losses. However, they also show strong antagonistic effects against economically important pathogens, demonstrating their potential for utilization as biological control agents. In addition, their metabolic versatility makes them attractive for the production of commercial biomolecules and bioremediation. An extensive comparative genomics study is required to dissect the mechanisms that Pcor and Pmed employ to cause disease, prevent disease caused by other pathogens, and to mine their genomes for commercially significant chemical pathways. Here, we present the draft genomes of nine Pcor and Pmed strains from different geographical locations. This analysis covered significant genetic heterogeneity and allowed in-depth genomic comparison. All examined strains were able to trigger symptoms in tomato plants but not all induced a hypersensitive-like response in Nicotiana benthamiana. Genome-mining revealed the absence of a type III secretion system and of known type III effectors from all examined Pcor and Pmed strains. The lack of a type III secretion system appears to be unique among the plant pathogenic pseudomonads. Several gene clusters coding for type VI secretion system were detected in all genomes.

  2. Comparative genomic analysis of multiple strains of two unusual plant pathogens: Pseudomonas corrugata and Pseudomonas mediterranea

    Science.gov (United States)

    Trantas, Emmanouil A.; Licciardello, Grazia; Almeida, Nalvo F.; Witek, Kamil; Strano, Cinzia P.; Duxbury, Zane; Ververidis, Filippos; Goumas, Dimitrios E.; Jones, Jonathan D. G.; Guttman, David S.; Catara, Vittoria; Sarris, Panagiotis F.

    2015-01-01

    The non-fluorescent pseudomonads, Pseudomonas corrugata (Pcor) and P. mediterranea (Pmed), are closely related species that cause pith necrosis, a disease of tomato that causes severe crop losses. However, they also show strong antagonistic effects against economically important pathogens, demonstrating their potential for utilization as biological control agents. In addition, their metabolic versatility makes them attractive for the production of commercial biomolecules and bioremediation. An extensive comparative genomics study is required to dissect the mechanisms that Pcor and Pmed employ to cause disease, prevent disease caused by other pathogens, and to mine their genomes for genes that encode proteins involved in commercially important chemical pathways. Here, we present the draft genomes of nine Pcor and Pmed strains from different geographical locations. This analysis covered significant genetic heterogeneity and allowed in-depth genomic comparison. All examined strains were able to trigger symptoms in tomato plants but not all induced a hypersensitive-like response in Nicotiana benthamiana. Genome-mining revealed the absence of type III secretion system and known type III effector-encoding genes from all examined Pcor and Pmed strains. The lack of a type III secretion system appears to be unique among the plant pathogenic pseudomonads. Several gene clusters coding for type VI secretion system were detected in all genomes. Genome-mining also revealed the presence of gene clusters for biosynthesis of siderophores, polyketides, non-ribosomal peptides, and hydrogen cyanide. A highly conserved quorum sensing system was detected in all strains, although species specific differences were observed. Our study provides the basis for in-depth investigations regarding the molecular mechanisms underlying virulence strategies in the battle between plants and microbes. PMID:26300874

  3. Analysis of the genome-wide variations among multiple strains of the plant pathogenic bacterium Xylella fastidiosa

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    Walker M Andrew

    2006-09-01

    Full Text Available Abstract Background The Gram-negative, xylem-limited phytopathogenic bacterium Xylella fastidiosa is responsible for causing economically important diseases in grapevine, citrus and many other plant species. Despite its economic impact, relatively little is known about the genomic variations among strains isolated from different hosts and their influence on the population genetics of this pathogen. With the availability of genome sequence information for four strains, it is now possible to perform genome-wide analyses to identify and categorize such DNA variations and to understand their influence on strain functional divergence. Results There are 1,579 genes and 194 non-coding homologous sequences present in the genomes of all four strains, representing a 76. 2% conservation of the sequenced genome. About 60% of the X. fastidiosa unique sequences exist as tandem gene clusters of 6 or more genes. Multiple alignments identified 12,754 SNPs and 14,449 INDELs in the 1528 common genes and 20,779 SNPs and 10,075 INDELs in the 194 non-coding sequences. The average SNP frequency was 1.08 × 10-2 per base pair of DNA and the average INDEL frequency was 2.06 × 10-2 per base pair of DNA. On an average, 60.33% of the SNPs were synonymous type while 39.67% were non-synonymous type. The mutation frequency, primarily in the form of external INDELs was the main type of sequence variation. The relative similarity between the strains was discussed according to the INDEL and SNP differences. The number of genes unique to each strain were 60 (9a5c, 54 (Dixon, 83 (Ann1 and 9 (Temecula-1. A sub-set of the strain specific genes showed significant differences in terms of their codon usage and GC composition from the native genes suggesting their xenologous origin. Tandem repeat analysis of the genomic sequences of the four strains identified associations of repeat sequences with hypothetical and phage related functions. Conclusion INDELs and strain specific genes

  4. Geographic isolates of Lymantria dispar multiple nucleopolyhedrovirus: Genome sequence analysis and pathogenicity against European and Asian gypsy moth strains.

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    Harrison, Robert L; Rowley, Daniel L; Keena, Melody A

    2016-06-01

    Isolates of the baculovirus species Lymantria dispar multiple nucleopolyhedrovirus have been formulated and applied to suppress outbreaks of the gypsy moth, L. dispar. To evaluate the genetic diversity in this species at the genomic level, the genomes of three isolates from Massachusetts, USA (LdMNPV-Ab-a624), Spain (LdMNPV-3054), and Japan (LdMNPV-3041) were sequenced and compared with four previously determined LdMNPV genome sequences. The LdMNPV genome sequences were collinear and contained the same homologous repeats (hrs) and clusters of baculovirus repeat orf (bro) gene family members in the same relative positions in their genomes, although sequence identities in these regions were low. Of 146 non-bro ORFs annotated in the genome of the representative isolate LdMNPV 5-6, 135 ORFs were found in every other LdMNPV genome, including the 37 core genes of Baculoviridae and other genes conserved in genus Alphabaculovirus. Phylogenetic inference with an alignment of the core gene nucleotide sequences grouped isolates 3041 (Japan) and 2161 (Korea) separately from a cluster containing isolates from Europe, North America, and Russia. To examine phenotypic diversity, bioassays were carried out with a selection of isolates against neonate larvae from three European gypsy moth (Lymantria dispar dispar) and three Asian gypsy moth (Lymantria dispar asiatica and Lymantria dispar japonica) colonies. LdMNPV isolates 2161 (Korea), 3029 (Russia), and 3041 (Japan) exhibited a greater degree of pathogenicity against all L. dispar strains than LdMNPV from a sample of Gypchek. This study provides additional information on the genetic diversity of LdMNPV isolates and their activity against the Asian gypsy moth, a potential invasive pest of North American trees and forests. Published by Elsevier Inc.

  5. Abundant and diverse clustered regularly interspaced short palindromic repeat spacers in Clostridium difficile strains and prophages target multiple phage types within this pathogen.

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    Hargreaves, Katherine R; Flores, Cesar O; Lawley, Trevor D; Clokie, Martha R J

    2014-08-26

    Clostridium difficile is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape C. difficile genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system. This uses acquired short nucleotide sequences (spacers) to target homologous sequences (protospacers) in phage genomes. C. difficile carries multiple CRISPR arrays, and in this paper we examine the relationships between the host- and phage-carried elements of the system. We detected multiple matches between spacers and regions in 31 C. difficile phage and prophage genomes. A subset of the spacers was located in prophage-carried CRISPR arrays. The CRISPR spacer profiles generated suggest that related phages would have similar host ranges. Furthermore, we show that C. difficile strains of the same ribotype could either have similar or divergent CRISPR contents. Both synonymous and nonsynonymous mutations in the protospacer sequences were identified, as well as differences in the protospacer adjacent motif (PAM), which could explain how phages escape this system. This paper illustrates how the distribution and diversity of CRISPR spacers in C. difficile, and its prophages, could modulate phage predation for this pathogen and impact upon its evolution and pathogenicity. Clostridium difficile is a significant bacterial human pathogen which undergoes continual genome evolution, resulting in the emergence of new virulent strains. Phages are major facilitators of genome evolution in other bacterial species, and we use sequence analysis-based approaches in order to examine whether the CRISPR/Cas system could control these interactions across divergent C. difficile strains. The presence of spacer sequences in prophages that are homologous to phage genomes raises an

  6. Comparative proteomic analysis of pathogenic and non-pathogenic strains from the swine pathogen Mycoplasma hyopneumoniae

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    Klein Cátia S

    2009-12-01

    Full Text Available Abstract Background Mycoplasma hyopneumoniae is a highly infectious swine pathogen and is the causative agent of enzootic pneumonia (EP. Following the previous report of a proteomic survey of the pathogenic 7448 strain of swine pathogen, Mycoplasma hyopneumoniae, we performed comparative protein profiling of three M. hyopneumoniae strains, namely the non-pathogenic J strain and the two pathogenic strains 7448 and 7422. Results In 2DE comparisons, we were able to identify differences in expression levels for 67 proteins, including the overexpression of some cytoadherence-related proteins only in the pathogenic strains. 2DE immunoblot analyses allowed the identification of differential proteolytic cleavage patterns of the P97 adhesin in the three strains. For more comprehensive protein profiling, an LC-MS/MS strategy was used. Overall, 35% of the M. hyopneumoniae genome coding capacity was covered. Partially overlapping profiles of identified proteins were observed in the strains with 81 proteins identified only in one strain and 54 proteins identified in two strains. Abundance analysis of proteins detected in more than one strain demonstrates the relative overexpression of 64 proteins, including the P97 adhesin in the pathogenic strains. Conclusions Our results indicate the physiological differences between the non-pathogenic strain, with its non-infective proliferate lifestyle, and the pathogenic strains, with its constitutive expression of adhesins, which would render the bacterium competent for adhesion and infection prior to host contact.

  7. Comparative genome analysis of pathogenic and non-pathogenic Clavibacter strains reveals adaptations to their lifestyle

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    Załuga, Joanna; Stragier, Pieter; Baeyen, Steve; Haegeman, Annelies; Van Vaerenbergh, Johan; Maes, Martine; De Vos, Paul

    2014-01-01

    Background The genus Clavibacter harbors economically important plant pathogens infecting agricultural crops such as potato and tomato. Although the vast majority of Clavibacter strains are pathogenic, there is an increasing number of non-pathogenic isolates reported. Non-pathogenic Clavibacter strains isolated from tomato seeds are particularly problematic because they affect the current detection and identification tests for Clavibacter michiganensis subsp. michiganensis (Cmm), which is reg...

  8. Comparative genome analysis of pathogenic and non-pathogenic Clavibacter strains reveals adaptations to their lifestyle.

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    Załuga, Joanna; Stragier, Pieter; Baeyen, Steve; Haegeman, Annelies; Van Vaerenbergh, Johan; Maes, Martine; De Vos, Paul

    2014-05-22

    The genus Clavibacter harbors economically important plant pathogens infecting agricultural crops such as potato and tomato. Although the vast majority of Clavibacter strains are pathogenic, there is an increasing number of non-pathogenic isolates reported. Non-pathogenic Clavibacter strains isolated from tomato seeds are particularly problematic because they affect the current detection and identification tests for Clavibacter michiganensis subsp. michiganensis (Cmm), which is regulated with a zero tolerance in tomato seed. Their misidentification as pathogenic Cmm hampers a clear judgment on the seed quality and health. To get more insight in the genetic features linked to the lifestyle of these bacteria, a whole-genome sequence of the tomato seed-borne non-pathogenic Clavibacter LMG 26808 was determined. To gain a better understanding of the molecular determinants of pathogenicity, the genome sequence of LMG 26808 was compared with that of the pathogenic Cmm strain (NCPPB 382). The comparative analysis revealed that LMG 26808 does not contain plasmids pCM1 and pCM2 and also lacks the majority of important virulence factors described so far for pathogenic Cmm. This explains its apparent non-pathogenic nature in tomato plants. Moreover, the genome analysis of LMG 26808 detected sequences from a plasmid originating from a member of Enterobacteriaceae/Klebsiella relative. Genes received that way and coding for antibiotic resistance may provide a competitive advantage for survival of LMG 26808 in its ecological niche. Genetically, LMG 26808 was the most similar to the pathogenic Cmm NCPPB 382 but contained more mobile genetic elements. The genome of this non-pathogenic Clavibacter strain contained also a high number of transporters and regulatory genes. The genome sequence of the non-pathogenic Clavibacter strain LMG 26808 and the comparative analyses with other pathogenic Clavibacter strains provided a better understanding of the genetic bases of virulence and

  9. Capturing the dynamics of pathogens with many strains

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    Kucharski, Adam; Andreasen, Viggo; Gog, Julia

    2016-01-01

    Pathogens that consist of multiple antigenic variants are a serious public health concern. These infections, which include dengue virus, influenza and malaria, generate substantial morbidity and mortality. However, there are considerable theoretical challenges involved in modelling such infection...

  10. Multiple-locus variable-number tandem-repeat analysis of pathogenic Yersinia enterocolitica in China.

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    Xin Wang

    Full Text Available The predominant bioserotypes of pathogenic Yersinia enterocolitica in China are 2/O: 9 and 3/O: 3; no pathogenic O: 8 strains have been found to date. Multiple-Locus Variable-Number Tandem-Repeat Analysis (MLVA based on seven loci was able to distinguish 104 genotypes among 218 pathogenic Y. enterocolitica isolates in China and from abroad, showing a high resolution. The major pathogenic serogroups in China, O: 3 and O: 9, were divided into two clusters based on MLVA genotyping. The different distribution of Y. enterocolitica MLVA genotypes maybe due to the recent dissemination of specific clones of 2/O: 9 and 3/O: 3 strains in China. MLVA was a helpful tool for bacterial pathogen surveillance and investigation of pathogenic Y. enterocolitica outbreaks.

  11. Recombinant Vaccinia Virus: Immunization against Multiple Pathogens

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    Perkus, Marion E.; Piccini, Antonia; Lipinskas, Bernard R.; Paoletti, Enzo

    1985-09-01

    The coding sequences for the hepatitis B virus surface antigen, the herpes simplex virus glycoprotein D, and the influenza virus hemagglutinin were inserted into a single vaccinia virus genome. Rabbits inoculated intravenously or intradermally with this polyvalent vaccinia virus recombinant produced antibodies reactive to all three authentic foreign antigens. In addition, the feasibility of multiple rounds of vaccination with recombinant vaccinia virus was demonstrated.

  12. Genome sequence of the pathogenic Herbaspirillum seropedicae strain Os34, isolated from rice roots.

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    Ye, Weijun; Ye, Shuting; Liu, Jian; Chang, Siping; Chen, Mingyue; Zhu, Bo; Guo, Longbiao; An, Qianli

    2012-12-01

    Most Herbaspirillum seropedicae strains are beneficial endophytes to plants. In contrast, H. seropedicae strain Os34, isolated from rice roots, is pathogenic. The draft genome sequence of strain Os34 presented here allows in-depth comparative genome analyses to understand the specific mechanisms of beneficial and pathogenic Herbaspirillum-plant interactions.

  13. Genome sequence of the pathogenic Herbaspirillum seropedicae strain Os45, isolated from rice roots.

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    Zhu, Bo; Ye, Shuting; Chang, Siping; Chen, Mingyue; Sun, Li; An, Qianli

    2012-12-01

    Most Herbaspirillum seropedicae strains are beneficial to plants. In contrast, H. seropedicae strain Os45, isolated from rice roots, is pathogenic. The draft genome sequence of strain Os45 presented here allows an in-depth comparative genome analysis to understand the subtle mechanisms of beneficial and pathogenic Herbaspirillum-plant interactions.

  14. Comparative genomics of transport proteins in probiotic and pathogenic Escherichia coli and Salmonella enterica strains.

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    Do, Jimmy; Zafar, Hassan; Saier, Milton H

    2017-06-01

    Escherichia coli is a genetically diverse species that can be pathogenic, probiotic, commensal, or a harmless laboratory strain. Pathogenic strains of E. coli cause urinary tract infections, diarrhea, hemorrhagic colitis, and pyelonephritis, while the two known probiotic E. coli strains combat inflammatory bowel disease and play a role in immunomodulation. Salmonella enterica, a close relative of E. coli, includes two important pathogenic serovars, Typhi and Typhimurium, causing typhoid fever and enterocolitis in humans, respectively, with the latter strain also causing a lethal typhoid fever-like disease in mice. In this study, we identify the transport systems and their substrates within seven E. coli strains: two probiotic strains, two extracellular pathogens, two intracellular pathogens, and K-12, as well as the two intracellular pathogenic S. enterica strains noted above. Transport systems characteristic of each probiotic or pathogenic species were thus identified, and the tabulated results obtained with all of these strains were compared. We found that the probiotic and pathogenic strains generally contain more iron-siderophore and sugar transporters than E. coli K-12. Pathogens have increased numbers of pore-forming toxins, protein secretion systems, decarboxylation-driven Na + exporters, electron flow-driven monovalent cation exporters, and putative transporters of unknown function compared to the probiotic strains. Both pathogens and probiotic strains encode metabolite transporters that reflect their intracellular versus extracellular environments. The results indicate that the probiotic strains live extracellularly. It seems that relatively few virulence factors can convert a beneficial or commensal microorganism into a pathogen. Taken together, the results reveal the distinguishing features of these strains and provide a starting point for future engineering of beneficial enteric bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Collagen-like proteins in pathogenic E. coli strains.

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    Neelanjana Ghosh

    Full Text Available The genome sequences of enterohaemorrhagic E. coli O157:H7 strains show multiple open-reading frames with collagen-like sequences that are absent from the common laboratory strain K-12. These putative collagens are included in prophages embedded in O157:H7 genomes. These prophages carry numerous genes related to strain virulence and have been shown to be inducible and capable of disseminating virulence factors by horizontal gene transfer. We have cloned two collagen-like proteins from E. coli O157:H7 into a laboratory strain and analysed the structure and conformation of the recombinant proteins and several of their constituting domains by a variety of spectroscopic, biophysical, and electron microscopy techniques. We show that these molecules exhibit many of the characteristics of vertebrate collagens, including trimer formation and the presence of a collagen triple helical domain. They also contain a C-terminal trimerization domain, and a trimeric α-helical coiled-coil domain with an unusual amino acid sequence almost completely lacking leucine, valine or isoleucine residues. Intriguingly, these molecules show high thermal stability, with the collagen domain being more stable than those of vertebrate fibrillar collagens, which are much longer and post-translationally modified. Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk. This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins. Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.

  16. Two avian H10 influenza A virus strains with different pathogenicity for mink (Mustela vison).

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    Englund, L; Hård af Segerstad, C

    1998-01-01

    We compared two strains of avian influenza A viruses of subtype H10 by exposing mink to aerosols of A/mink/Sweden/3,900/84 (H10N4) naturally pathogenic for mink, or A/chicken/Germany/N/49, (H10N7). Lesions in the respiratory tract during the first week after infection were studied and described. Both virus strains caused inflammatory reactions in the lungs and antibody production in exposed mink but only mink/84 virus was reisolated. The lesions caused by mink/84 virus were more severe with higher area density of pneumonia, lower daily weight gain, and more virus in the tissues detected by immunohistochemistry. The results indicate that mink/84 (H10N4), but not chicken/49 virus (H10N7), established multiple cycle replication in infected cells in the mink.

  17. Antagonistic Activity of Lactobacillus reuteri Strains on the Adhesion Characteristics of Selected Pathogens.

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    Singh, Tejinder P; Kaur, Gurpreet; Kapila, Suman; Malik, Ravinder K

    2017-01-01

    Adhesion ability of probiotics is the key factor that decides their colonization in the gastrointestinal tract and potential to inhibit pathogens. Therefore, adhesion ability can be considered as a key determinant for probiotic efficacy. Presents study documents the antagonistic activity of viable/untreated, Lithium chloride (LiCl) treated or heat-killed forms of eight probiotic Lactobacillus reuteri strains on the adhesion characteristics of selected pathogens. All strains investigated were able to adhere to Caco-2 cells. L. reuteri strains tested were able to inhibit and displace ( P strain L. reuteri LR6 showed the strongest adhesion and pathogen inhibition ability among the eight L. reuteri strains tested. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting the involvement of various mechanisms. The adhesion and antagonistic potential of the probiotic strains were significantly decreased upon exposure to 5 M LiCl, showing that surface molecules, proteinaceous in nature, are involved. The heat-killed forms of the probiotic L. reuteri strains also inhibited the attachment of selected pathogens to Caco-2 cells. In conclusion, in vitro assays showed that L. reuteri strains, as viable or heat-killed forms, are adherent to Caco-2 cells and are highly antagonistic to pathogens tested in which surface associated proteins play an important role.

  18. Vibrio tapetis Displays an Original Type IV Secretion System in Strains Pathogenic for Bivalve Molluscs

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    Graciela M. Dias

    2018-02-01

    Full Text Available The Brown Ring Disease (BRD caused high mortality rates since 1986 in the Manila clam Venerupis philippinarum introduced and cultured in Western Europe from the 1970s. The causative agent of BRD is a Gram-Negative bacterium, Vibrio tapetis, which is also pathogenic to fish. Here we report the first assembly of the complete genome of V. tapetis CECT4600T, together with the genome sequences of 16 additional strains isolated across a broad host and geographic range. Our extensive genome dataset allowed us to describe the pathogen pan- and core genomes and to identify putative virulence factors. The V. tapetis core genome consists of 3,352 genes, including multiple potential virulence factors represented by haemolysins, transcriptional regulators, Type I restriction modification system, GGDEF domain proteins, several conjugative plasmids, and a Type IV secretion system. Future research on the coevolutionary arms race between V. tapetis virulence factors and host resistance mechanisms will improve our understanding of how pathogenicity develops in this emerging pathogen.

  19. Multiple Genome Sequences of Lactobacillus plantarum Strains

    OpenAIRE

    Kafka, Thomas A.; Geissler, Andreas J.; Vogel, Rudi F.

    2017-01-01

    ABSTRACT We report here the genome sequences of four Lactobacillus plantarum strains which vary in surface hydrophobicity. Bioinformatic analysis, using additional genomes of Lactobacillus plantarum strains, revealed a possible correlation between the cell wall teichoic acid-type and cell surface hydrophobicity and provide the basis for consecutive analyses.

  20. Role of commercial probiotic strains against human pathogen adhesion to intestinal mucus.

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    Collado, M C; Meriluoto, J; Salminen, S

    2007-10-01

    The aims of this study present were to assess and to evaluate in vitro the abilities of commercial probiotic strains derived from fermented milk products and related sources currently marketed in European countries, to inhibit, compete and displace the adhesion of selected potential pathogens to immobilized human mucus. The adhesion was assessed by measuring the radioactivity of bacteria adhered to the human mucus. We tested 12 probiotic strains against eight selected pathogens. All strains tested were able to adhere to mucus. All probiotic strains tested were able to inhibit and displace (P<0.05) the adhesion of Bacteroides, Clostridium, Staphylococcus and Enterobacter. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting that several complementary mechanisms are implied in the processes. Our results indicate the need for a case-by-case assessment in order to select strains with the ability to inhibit or displace a specific pathogen. Probiotics could be useful to correct deviations observed in intestinal microbiota associated with specific diseases and also, to prevent pathogen infections. The competitive exclusion properties of probiotics as well as their ability to displace and inhibit pathogens are the most importance for therapeutic manipulation of the enteric microbiota. The application of such strategies could contribute to expand the beneficial properties on human health against pathogen infection.

  1. Multiple infections of rodents with zoonotic pathogens in Austria.

    Science.gov (United States)

    Schmidt, Sabrina; Essbauer, Sandra S; Mayer-Scholl, Anne; Poppert, Sven; Schmidt-Chanasit, Jonas; Klempa, Boris; Henning, Klaus; Schares, Gereon; Groschup, Martin H; Spitzenberger, Friederike; Richter, Dania; Heckel, Gerald; Ulrich, Rainer G

    2014-07-01

    Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host-pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans.

  2. Persistence of Pathogenic and Non-Pathogenic Escherichia coli Strains in Various Tropical Agricultural Soils of India.

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    S Naganandhini

    Full Text Available The persistence of Shiga-like toxin producing E. coli (STEC strains in the agricultural soil creates serious threat to human health through fresh vegetables growing on them. However, the survival of STEC strains in Indian tropical soils is not yet understood thoroughly. Additionally how the survival of STEC strain in soil diverges with non-pathogenic and genetically modified E. coli strains is also not yet assessed. Hence in the present study, the survival pattern of STEC strain (O157-TNAU was compared with non-pathogenic (MTCC433 and genetically modified (DH5α strains on different tropical agricultural soils and on a vegetable growing medium, cocopeat under controlled condition. The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days than those compared (60 days. Similarly, among the soils assessed, the red laterite and tropical latosol supported longer survival of O157-TNAU and MTCC433 as compared to wetland and black cotton soils. In cocopeat, O157 recorded significantly longer survival than other two strains. The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA. The PCA of all the three strains revealed that pH, microbial biomass carbon, dehydrogenase activity and available N and P contents of the soil decided the survival of E. coli strains in those soils and cocopeat. The present research work suggests that the survival of O157 differs in tropical Indian soils due to varied physico-chemical and biological properties and the survival is much shorter than those reported in temperate soils. As the survival pattern of non-pathogenic strain, MTCC433 is similar to O157-TNAU in tropical soils, the former can be used as safe model organism for open field studies.

  3. The Genetically Remote Pathogenic Strain NVH391-98 of the Bacillus cereus Group Represents the Cluster of Thermophilic Strains

    Energy Technology Data Exchange (ETDEWEB)

    Auger, Sandrine; Galleron, Nathalie; Bidnenko, Elena; Ehrlich, S. Dusko; Lapidus, Alla; Sorokin, Alexei

    2007-10-02

    Bacteria of the Bacillus cereus group are known to cause food poisoning. A rare phylogenetically remote strain, NVH391-98, was recently characterized to encode a particularly efficient cytotoxin K presumably responsible for food poisoning. This pathogenic strain and its close relatives can be phenotypically distinguished from other strains of the B. cereus group by the inability to grow at temperatures below 17 degrees C and by the ability to grow at temperatures from 48 to 53 degrees C. A temperate phage, phBC391A2, residing in the genome of NVH391-98 allows us to distinguish the three known members of this thermophilic strain cluster.

  4. Antagonistic Activity of Lactobacillus reuteri Strains on the Adhesion Characteristics of Selected Pathogens

    OpenAIRE

    Singh, Tejinder P.; Kaur, Gurpreet; Kapila, Suman; Malik, Ravinder K.

    2017-01-01

    Adhesion ability of probiotics is the key factor that decides their colonization in the gastrointestinal tract and potential to inhibit pathogens. Therefore, adhesion ability can be considered as a key determinant for probiotic efficacy. Presents study documents the antagonistic activity of viable/untreated, Lithium chloride (LiCl) treated or heat-killed forms of eight probiotic Lactobacillus reuteri strains on the adhesion characteristics of selected pathogens. All strains investigated were ...

  5. Morphological characterization of several strains of the rice-pathogenic bacterium Burkholderia glumae in North Sumatra

    Science.gov (United States)

    Hasibuan, M.; Safni, I.; Lisnawita; Lubis, K.

    2018-02-01

    Burkholderia glumae is a quarantine seed-borne bacterial pathogen causing panicle blight disease on rice. This pathogen has been detected in some locations in Java, and recently, farmers in North Sumatra have reported rice yield loss with symptoms similar with those on rice infeced by the rice-pathogenic bacterium B. glumae. This research was aimed to isolate several bacterial strains from several rice varieties in various locations in North Sumatra and characterize the morphology of the strains to detect and identify the unknown bacterial strains presumably B. glumae. Several rice seed varieties were collected from Medan and Deli Serdang Districts. The seed samples were extracted, isolated and purified, then grown in semi-selective media PPGA. The morphological characteristics of the bacterial strains were determined including Gram staining, bacterial colony’s and bacterial cell’s morphology. The results showed that of eleven strains isolated, two strains were Gram negative and nine strains were Gram positive. On the basis of colony morphology, all strains had circular form, flat elevation and cream colour while the colony margin varied, i.e. entire and undulate. Most strains had bacillus/rod shape (8 strains) and only 3 strains were coccus.

  6. Antagonistic activities of some Bifidobacterium sp. strains isolated from resident infant gastrointestinal microbiota on Gram-negative enteric pathogens.

    Science.gov (United States)

    Delcaru, Cristina; Alexandru, Ionela; Podgoreanu, Paulina; Cristea, Violeta Corina; Bleotu, Coralia; Chifiriuc, Mariana Carmen; Bezirtzoglou, Eugenia; Lazar, Veronica

    2016-06-01

    The gastrointestinal microbiota contributes to the consolidation of the anti-infectious barrier against enteric pathogens. The purpose of this study was to investigate the influence of Bifidobacterium sp. strains, recently isolated from infant gastrointestinal microbiota on the in vitro growth and virulence features expression of enteropathogenic bacterial strains. The antibacterial activity of twelve Bifidobacterium sp. strains isolated from human feces was examined in vitro against a wide range of Gram negative pathogenic strains isolated from 30 infant patients (3 days to 5 years old) with diarrhea. Both potential probiotic strains (Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bifidobacterium catenulatum, Bifidobacterium breve, Bifidobacterium ruminantium) and enteropathogenic strains (EPEC, EIEC, Klebsiella pneumoniae, Salmonella sp., Yersinia enterocolitica, Pseudomonas aeruginosa) were identified by MALDI-TOF and confirmed serologically when needed. The bactericidal activity, growth curve, adherence to the cellular HEp-2 substratum and production of soluble virulence factors have been assessed in the presence of different Bifidobacterium sp. cultures and fractions (whole culture and free-cell supernatants). Among the twelve Bifidobacterium sp. strains, the largest spectrum of antimicrobial activity against 9 of the 18 enteropathogenic strains was revealed for a B. breve strain recently isolated from infant intestinal feces. The whole culture and free-cell supernatant of B. breve culture decreased the multiplication rate, shortened the log phase and the total duration of the growth curve, with an earlier entrance in the decline phase and inhibited the adherence capacity to a cellular substratum and the swimming/swarming motility too. These results indicate the significant probiotic potential of the B. breve strain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Progressive multiple sclerosis: from pathogenic mechanisms to treatment.

    Science.gov (United States)

    Correale, Jorge; Gaitán, María I; Ysrraelit, María C; Fiol, Marcela P

    2017-03-01

    During the past decades, better understanding of relapsing-remitting multiple sclerosis disease mechanisms have led to the development of several disease-modifying therapies, reducing relapse rates and severity, through immune system modulation or suppression. In contrast, current therapeutic options for progressive multiple sclerosis remain comparatively disappointing and challenging. One possible explanation is a lack of understanding of pathogenic mechanisms driving progressive multiple sclerosis. Furthermore, diagnosis is usually retrospective, based on history of gradual neurological worsening with or without occasional relapses, minor remissions or plateaus. In addition, imaging methods as well as biomarkers are not well established. Magnetic resonance imaging studies in progressive multiple sclerosis show decreased blood-brain barrier permeability, probably reflecting compartmentalization of inflammation behind a relatively intact blood-brain barrier. Interestingly, a spectrum of inflammatory cell types infiltrates the leptomeninges during subpial cortical demyelination. Indeed, recent magnetic resonance imaging studies show leptomeningeal contrast enhancement in subjects with progressive multiple sclerosis, possibly representing an in vivo marker of inflammation associated to subpial demyelination. Treatments for progressive disease depend on underlying mechanisms causing central nervous system damage. Immunity sheltered behind an intact blood-brain barrier, energy failure, and membrane channel dysfunction may be key processes in progressive disease. Interfering with these mechanisms may provide neuroprotection and prevent disability progression, while potentially restoring activity and conduction along damaged axons by repairing myelin. Although most previous clinical trials in progressive multiple sclerosis have yielded disappointing results, important lessons have been learnt, improving the design of novel ones. This review discusses mechanisms involved

  8. Use of bacillus subtilis strains to inhibit postharvest pathogenic fungi

    International Nuclear Information System (INIS)

    Arras, G.; Gambella, F.; Demontis, S.; Petretto, A.

    1995-01-01

    An isolate (87) of the bacillus subtilis strains isolated from cold stored citrus fruit 13 proved to inhibit the growth in vitro of the penicillium italicum used in the experiment (from 50.6% to 92.2%) and to inhibit botrytis cinerea (from 65.3% to 95.9%). A further test, superimposing on plates containing PDA strains Nos. 13, 173, and 160, totally inhibited the fungi. Tested in vivo on artificially bruised oranges, they significantly inhibited two fungi

  9. Genomic survey of pathogenicity determinants and VNTR markers in the cassava bacterial pathogen Xanthomonas axonopodis pv. Manihotis strain CIO151.

    Science.gov (United States)

    Arrieta-Ortiz, Mario L; Rodríguez-R, Luis M; Pérez-Quintero, Álvaro L; Poulin, Lucie; Díaz, Ana C; Arias Rojas, Nathalia; Trujillo, Cesar; Restrepo Benavides, Mariana; Bart, Rebecca; Boch, Jens; Boureau, Tristan; Darrasse, Armelle; David, Perrine; Dugé de Bernonville, Thomas; Fontanilla, Paula; Gagnevin, Lionel; Guérin, Fabien; Jacques, Marie-Agnès; Lauber, Emmanuelle; Lefeuvre, Pierre; Medina, Cesar; Medina, Edgar; Montenegro, Nathaly; Muñoz Bodnar, Alejandra; Noël, Laurent D; Ortiz Quiñones, Juan F; Osorio, Daniela; Pardo, Carolina; Patil, Prabhu B; Poussier, Stéphane; Pruvost, Olivier; Robène-Soustrade, Isabelle; Ryan, Robert P; Tabima, Javier; Urrego Morales, Oscar G; Vernière, Christian; Carrere, Sébastien; Verdier, Valérie; Szurek, Boris; Restrepo, Silvia; López, Camilo; Koebnik, Ralf; Bernal, Adriana

    2013-01-01

    Xanthomonas axonopodis pv. manihotis (Xam) is the causal agent of bacterial blight of cassava, which is among the main components of human diet in Africa and South America. Current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. Previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable tools for diagnostics and detection. Here we have generated the first manually annotated high-quality draft genome sequence of Xam strain CIO151. Its genomic structure is similar to that of other xanthomonads, especially Xanthomonas euvesicatoria and Xanthomonas citri pv. citri species. Several putative pathogenicity factors were identified, including type III effectors, cell wall-degrading enzymes and clusters encoding protein secretion systems. Specific characteristics in this genome include changes in the xanthomonadin cluster that could explain the lack of typical yellow color in all strains of this pathovar and the presence of 50 regions in the genome with atypical nucleotide composition. The genome sequence was used to predict and evaluate 22 variable number of tandem repeat (VNTR) loci that were subsequently demonstrated as polymorphic in representative Xam strains. Our results demonstrate that Xanthomonas axonopodis pv. manihotis strain CIO151 possesses ten clusters of pathogenicity factors conserved within the genus Xanthomonas. We report 126 genes that are potentially unique to Xam, as well as potential horizontal transfer events in the history of the genome. The relation of these regions with virulence and pathogenicity could explain several aspects of the biology of this pathogen, including its ability to colonize both vascular and non-vascular tissues of cassava plants. A set of 16 robust, polymorphic VNTR loci will be useful to develop a multi-locus VNTR analysis

  10. Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains.

    Science.gov (United States)

    Argemi, Xavier; Nanoukon, Chimène; Affolabi, Dissou; Keller, Daniel; Hansmann, Yves; Riegel, Philippe; Baba-Moussa, Lamine; Prévost, Gilles

    2018-02-25

    Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus ; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC) similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8-89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes ( hsrA and dfrG , respectively), and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus . Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis .

  11. Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains

    Directory of Open Access Journals (Sweden)

    Xavier Argemi

    2018-02-01

    Full Text Available Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8–89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes (hsrA and dfrG, respectively, and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus. Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis.

  12. Draft genome sequences of two opportunistic pathogenic strains of Staphylococcus cohnii isolated from human patients

    OpenAIRE

    Mendoza-Olazar?n, Soraya; Garcia-Mazcorro, Jos? F.; Morf?n-Otero, Rayo; Villarreal-Trevi?o, Licet; Camacho-Ortiz, Adri?n; Rodr?guez-Noriega, Eduardo; Bocanegra-Ibarias, Paola; Maldonado-Garza, H?ctor J.; Dowd, Scot E.; Garza-Gonz?lez, Elvira

    2017-01-01

    Herein, we report the draft-genome sequences and annotation of two opportunistic pathogenic strains of Staphylococcus cohnii isolated from humans. One strain (SC-57) was isolated from blood from a male patient in May 2006 and the other (SC-532) from a catheter from a male patient in June 2006. Similar to other genomes of Staphylococcus species, most genes (42%) of both strains are involved in metabolism of amino acids and derivatives, carbohydrates and proteins. Eighty (4%) genes are involved...

  13. Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs.

    Science.gov (United States)

    Vahjen, W; Cuisiniere, T; Zentek, J

    2017-10-13

    To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic

  14. Experimental single-strain mobilomics reveals events that shape pathogen emergence.

    Science.gov (United States)

    Schoeniger, Joseph S; Hudson, Corey M; Bent, Zachary W; Sinha, Anupama; Williams, Kelly P

    2016-08-19

    Virulence genes on mobile DNAs such as genomic islands (GIs) and plasmids promote bacterial pathogen emergence. Excision is an early step in GI mobilization, producing a circular GI and a deletion site in the chromosome; circular forms are also known for some bacterial insertion sequences (ISs). The recombinant sequence at the junctions of such circles and deletions can be detected sensitively in high-throughput sequencing data, using new computational methods that enable empirical discovery of mobile DNAs. For the rich mobilome of a hospital Klebsiella pneumoniae strain, circularization junctions (CJs) were detected for six GIs and seven IS types. Our methods revealed differential biology of multiple mobile DNAs, imprecision of integrases and transposases, and differential activity among identical IS copies for IS26, ISKpn18 and ISKpn21 Using the resistance of circular dsDNA molecules to exonuclease, internally calibrated with the native plasmids, showed that not all molecules bearing GI CJs were circular. Transpositions were also detected, revealing replicon preference (ISKpn18 prefers a conjugative IncA/C2 plasmid), local action (IS26), regional preferences, selection (against capsule synthesis) and IS polarity inversion. Efficient discovery and global characterization of numerous mobile elements per experiment improves accounting for the new gene combinations that arise in emerging pathogens. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Inhibitory potential of nine mentha species against pathogenic bacteria strains

    International Nuclear Information System (INIS)

    Hussain, A.; Ahmad, N.; Rashid, M.; Ikram, A. U.; Shinwari, Z. K.

    2015-01-01

    Plants produce secondary metabolites, which are used in their growth and defense against pathogenic agents. These plant based metabolites can be used as natural antibiotics against pathogenic bacteria. Synthetic antibiotics caused different side effects and become resistant to bacteria. Therefore the main objective of the present study was to investigate the inhibitory potential of nine Mentha species extracts against pathogenic bacteria. The methanolic leaves extracts of nine Mentha species (Mentha arvensis, Mentha longifolia, Mentha officinalis, Mentha piperita, Mentha citrata, Mentha pulegium, Mentha royleana, Mentha spicata and Mentha suareolens) were compared for antimicrobial activities. These Mentha species showed strong antibacterial activity against four microorganisms tested. Mentha arvensis showed 25 mm and 30 mm zones of inhibition against Staphylococcus aureus, Vibrio cholera and Enterobacter aerogens. Moreover, Mentha longifolia showed 24 mm zone of inhibition against Staphylococcus aureus. Mentha officinalis showed 30 mm zone of inhibition against Staphylococcus aureus. 25 mm inhibitory zone was recorded against Staphylococcus aureus by Mentha piperita. Mentha royleana showed 25 mm zone of inhibition against Vibrio cholera, while Mentha spicata showed 21 mm, 22 mm and 23 mm zones of inhibition against Staphylococcus aureus, Vibrio cholera and Enterobacter aerogens. Moreover most of the Mentha species showed zone of inhibition in the range of 10-20 mm. (author)

  16. Isolation of pathogenic Yersinia enterocolitica strains from different sources in Izmir region, Turkey.

    Science.gov (United States)

    Bozcal, Elif; Uzel, Atac; Aydemir, Sohret; Skurnik, Mikael

    2015-11-01

    Yersinia enterocolitica is a foodborne pathogen that is very rarely encountered in Turkey. In this work, several human, porcine, and environmental samples collected from Izmir region in Turkey were examined for the presence of Y. enterocolitica using different cultivation and enrichment methods. A total of nine pathogenic Y. enterocolitica strains were isolated; five strains from pig stool and manure samples and four strains from waste water samples. On the other hand, no Y. enterocolitica was isolated from human diarrheal stool samples (n = 102) and from 12 gulf, canal, municipal pool, and well water samples. Biochemical and serological characterization of the nine Y. enterocolitica strains revealed that they belonged to three different bioserotypes: 4/O:3, 2/O:9, and 2/O:5,27. All the strains were deemed pathogenic based on virulence factor-specific PCR analysis. Detection of pathogenic Y. enterocolitica strains from the pig and waste water samples from the Izmir region indicates that Y. enterocolitica is a potential risk for public health.

  17. Strain preservation of experimental animals: vitrification of two-cell stage embryos for multiple mouse strains.

    Science.gov (United States)

    Eto, Tomoo; Takahashi, Riichi; Kamisako, Tsutomu

    2015-04-01

    Strain preservation of experimental animals is crucial for experimental reproducibility. Maintaining complete animal strains, however, is costly and there is a risk for genetic mutations as well as complete loss due to disasters or illness. Therefore, the development of effective vitrification techniques for cryopreservation of multiple experimental animal strains is important. We examined whether a vitrification method using cryoprotectant solutions, P10 and PEPeS, is suitable for preservation of multiple inbred and outbred mouse strains. First, we investigated whether our vitrification method using cryoprotectant solutions was suitable for two-cell stage mouse embryos. In vitro development of embryos exposed to the cryoprotectant solutions was similar to that of fresh controls. Further, the survival rate of the vitrified embryos was extremely high (98.1%). Next, we collected and vitrified two-cell stage embryos of 14 mouse strains. The average number of embryos obtained from one female was 7.3-33.3. The survival rate of vitrified embryos ranged from 92.8% to 99.1%, with no significant differences among mouse strains. In vivo development did not differ significantly between fresh controls and vitrified embryos of each strain. For strain preservation using cryopreserved embryos, two offspring for inbred lines and one offspring for outbred lines must be produced from two-cell stage embryos collected from one female. The expected number of surviving fetuses obtained from embryos collected from one female of either the inbred or outbred strains ranged from 2.9 to 19.5. The findings of the present study indicated that this vitrification method is suitable for strain preservation of multiple mouse strains. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  18. A comparison of the adaptations of strains of Lymantria dispar multiple nucleopolyhedrovirus to hosts from spatially isolated populations

    Science.gov (United States)

    V.V. Martemyanov; J.D. Podgwaite; I.A. Belousova; S.V. Pavlushin; J.M. Slavicek; O.A. Baturina; M.R. Kabilov; A.V. Ilyinykh

    2017-01-01

    The adaptation of pathogens to either their hosts or to environmental conditions is the focus of many current ecological studies. In this work we compared the ability of six spatially-distant Lymantria dispar (gypsy moth) multiple nucleopolyhedrovirus (LdMNPV) strains (three from eastern North America and three from central Asia) to induce acute...

  19. Spread of Botrytis cinerea Strains with Multiple Fungicide Resistance in German Horticulture.

    Science.gov (United States)

    Rupp, Sabrina; Weber, Roland W S; Rieger, Daniel; Detzel, Peter; Hahn, Matthias

    2016-01-01

    Botrytis cinerea is a major plant pathogen, causing gray mold rot in a variety of cultures. Repeated fungicide applications are common but have resulted in the development of fungal populations with resistance to one or more fungicides. In this study, we have monitored fungicide resistance frequencies and the occurrence of multiple resistance in Botrytis isolates from raspberries, strawberries, grapes, stone fruits and ornamental flowers in Germany in 2010 to 2015. High frequencies of resistance to all classes of botryticides was common in all cultures, and isolates with multiple fungicide resistance represented a major part of the populations. A monitoring in a raspberry field over six seasons revealed a continuous increase in resistance frequencies and the emergence of multiresistant Botrytis strains. In a cherry orchard and a vineyard, evidence of the immigration of multiresistant strains from the outside was obtained. Inoculation experiments with fungicide-treated leaves in the laboratory and with strawberry plants cultivated in the greenhouse or outdoors revealed a nearly complete loss of fungicide efficacy against multiresistant strains. B. cinerea field strains carrying multiple resistance mutations against all classes of site-specific fungicides were found to show similar fitness as sensitive field strains under laboratory conditions, based on their vegetative growth, reproduction, stress resistance, virulence and competitiveness in mixed infection experiments. Our data indicate an alarming increase in the occurrence of multiresistance in B. cinerea populations from different cultures, which presents a major threat to the chemical control of gray mold.

  20. Molecular Identification and Genetic Characterization of Macrophomina phaseolina Strains Causing Pathogenicity on Sunflower and Chickpea

    Directory of Open Access Journals (Sweden)

    Ali N. Khan

    2017-07-01

    Full Text Available Macrophomina phaseolina is the most devastating pathogen which causes charcoal rot and root rot diseases in various economically important crops. Three strains M. phaseolina 1156, M. phaseolina 1160, and M. phaseolina PCMC/F1 were tested for their virulence on sunflower (Helianthus annuus L. and chickpea (Cicer arietinum L.. The strains showed high virulence on both hosts with a disease score of 2 on chickpea and sunflower. The strains also increased the hydrogen per oxide (H2O2 content by 1.4- to 1.6-fold in root as well as shoot of chickpea and sunflower. A significant increase in antioxidant enzymes was observed in fungal infected plants which indicated prevalence of oxidative stress during pathogen propagation. The M. phaseolina strains also produced hydrolytic enzymes such as lipase, amylase, and protease with solubilization zone of 5–43 mm, 5–45 mm, and 12–35 mm, respectively. The M. phaseolina strains were identified by 18S rRNA and analyzed for genetic diversity by using random amplified polymorphic DNA (RAPD markers. The findings based on RAPD markers and 18S rRNA sequence analysis clearly indicate genetic variation among the strains collected from different hosts. The genetically diverse strains were found to be pathogenic to sunflower and chickpea.

  1. Influence of Temperature on the Physiology and Virulence of the Insect Pathogen Serratia sp. Strain SCBI

    Science.gov (United States)

    Petersen, Lauren M.

    2012-01-01

    The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them. PMID:23042169

  2. Influence of temperature on the physiology and virulence of the insect pathogen Serratia sp. Strain SCBI.

    Science.gov (United States)

    Petersen, Lauren M; Tisa, Louis S

    2012-12-01

    The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them.

  3. Multiple pathogenic proteins implicated in neuronopathic Gaucher disease mice.

    Science.gov (United States)

    Xu, You-hai; Xu, Kui; Sun, Ying; Liou, Benjamin; Quinn, Brian; Li, Rong-hua; Xue, Ling; Zhang, Wujuan; Setchell, Kenneth D R; Witte, David; Grabowski, Gregory A

    2014-08-01

    Gaucher disease, a prevalent lysosomal storage disease (LSD), is caused by insufficient activity of acid β-glucosidase (GCase) and the resultant glucosylceramide (GC)/glucosylsphingosine (GS) accumulation in visceral organs (Type 1) and the central nervous system (Types 2 and 3). Recent clinical and genetic studies implicate a pathogenic link between Gaucher and neurodegenerative diseases. The aggregation and inclusion bodies of α-synuclein with ubiquitin are present in the brains of Gaucher disease patients and mouse models. Indirect evidence of β-amyloid pathology promoting α-synuclein fibrillation supports these pathogenic proteins as a common feature in neurodegenerative diseases. Here, multiple proteins are implicated in the pathogenesis of chronic neuronopathic Gaucher disease (nGD). Immunohistochemical and biochemical analyses showed significant amounts of β-amyloid and amyloid precursor protein (APP) aggregates in the cortex, hippocampus, stratum and substantia nigra of the nGD mice. APP aggregates were in neuronal cells and colocalized with α-synuclein signals. A majority of APP co-localized with the mitochondrial markers TOM40 and Cox IV; a small portion co-localized with the autophagy proteins, P62/LC3, and the lysosomal marker, LAMP1. In cultured wild-type brain cortical neural cells, the GCase-irreversible inhibitor, conduritol B epoxide (CBE), reproduced the APP/α-synuclein aggregation and the accumulation of GC/GS. Ultrastructural studies showed numerous larger-sized and electron-dense mitochondria in nGD cerebral cortical neural cells. Significant reductions of mitochondrial adenosine triphosphate production and oxygen consumption (28-40%) were detected in nGD brains and in CBE-treated neural cells. These studies implicate defective GCase function and GC/GS accumulation as risk factors for mitochondrial dysfunction and the multi-proteinopathies (α-synuclein-, APP- and Aβ-aggregates) in nGD. © The Author 2014. Published by Oxford University

  4. Genetic recombination between human and animal parasites creates novel strains of human pathogen.

    Directory of Open Access Journals (Sweden)

    Wendy Gibson

    2015-03-01

    Full Text Available Genetic recombination between pathogens derived from humans and livestock has the potential to create novel pathogen strains, highlighted by the influenza pandemic H1N1/09, which was derived from a re-assortment of swine, avian and human influenza A viruses. Here we investigated whether genetic recombination between subspecies of the protozoan parasite, Trypanosoma brucei, from humans and animals can generate new strains of human pathogen, T. b. rhodesiense (Tbr responsible for sleeping sickness (Human African Trypanosomiasis, HAT in East Africa. The trait of human infectivity in Tbr is conferred by a single gene, SRA, which is potentially transferable to the animal pathogen Tbb by sexual reproduction. We tracked the inheritance of SRA in crosses of Tbr and Tbb set up by co-transmitting genetically-engineered fluorescent parental trypanosome lines through tsetse flies. SRA was readily transferred into new genetic backgrounds by sexual reproduction between Tbr and Tbb, thus creating new strains of the human pathogen, Tbr. There was no evidence of diminished growth or transmissibility of hybrid trypanosomes carrying SRA. Although expression of SRA is critical to survival of Tbr in the human host, we show that the gene exists as a single copy in a representative collection of Tbr strains. SRA was found on one homologue of chromosome IV in the majority of Tbr isolates examined, but some Ugandan Tbr had SRA on both homologues. The mobility of SRA by genetic recombination readily explains the observed genetic variability of Tbr in East Africa. We conclude that new strains of the human pathogen Tbr are being generated continuously by recombination with the much larger pool of animal-infective trypanosomes. Such novel recombinants present a risk for future outbreaks of HAT.

  5. Genetic recombination between human and animal parasites creates novel strains of human pathogen.

    Science.gov (United States)

    Gibson, Wendy; Peacock, Lori; Ferris, Vanessa; Fischer, Katrin; Livingstone, Jennifer; Thomas, James; Bailey, Mick

    2015-03-01

    Genetic recombination between pathogens derived from humans and livestock has the potential to create novel pathogen strains, highlighted by the influenza pandemic H1N1/09, which was derived from a re-assortment of swine, avian and human influenza A viruses. Here we investigated whether genetic recombination between subspecies of the protozoan parasite, Trypanosoma brucei, from humans and animals can generate new strains of human pathogen, T. b. rhodesiense (Tbr) responsible for sleeping sickness (Human African Trypanosomiasis, HAT) in East Africa. The trait of human infectivity in Tbr is conferred by a single gene, SRA, which is potentially transferable to the animal pathogen Tbb by sexual reproduction. We tracked the inheritance of SRA in crosses of Tbr and Tbb set up by co-transmitting genetically-engineered fluorescent parental trypanosome lines through tsetse flies. SRA was readily transferred into new genetic backgrounds by sexual reproduction between Tbr and Tbb, thus creating new strains of the human pathogen, Tbr. There was no evidence of diminished growth or transmissibility of hybrid trypanosomes carrying SRA. Although expression of SRA is critical to survival of Tbr in the human host, we show that the gene exists as a single copy in a representative collection of Tbr strains. SRA was found on one homologue of chromosome IV in the majority of Tbr isolates examined, but some Ugandan Tbr had SRA on both homologues. The mobility of SRA by genetic recombination readily explains the observed genetic variability of Tbr in East Africa. We conclude that new strains of the human pathogen Tbr are being generated continuously by recombination with the much larger pool of animal-infective trypanosomes. Such novel recombinants present a risk for future outbreaks of HAT.

  6. Comparative in vitro inhibition of urinary tract pathogens by single- and multi-strain probiotics.

    Science.gov (United States)

    Chapman, C M C; Gibson, G R; Todd, S; Rowland, I

    2013-09-01

    Multi-species probiotic preparations have been suggested as having a wide spectrum of application, although few studies have compared their efficacy with that of individual component strains at equal concentrations. We therefore tested the ability of 4 single probiotics and 4 probiotic mixtures to inhibit the urinary tract pathogens Escherichia coli NCTC 9001 and Enterococcus faecalis NCTC 00775. We used an agar spot test to test the ability of viable cells to inhibit pathogens, while a broth inhibition assay was used to assess inhibition by cell-free probiotic supernatants in both pH-neutralised and non-neutralised forms. In the agar spot test, all probiotic treatments showed inhibition, L. acidophilus was the most inhibitory single strain against E. faecalis, L. fermentum the most inhibitory against E. coli. A commercially available mixture of 14 strains (Bio-Kult(®)) was the most effective mixture, against E. faecalis, the 3-lactobacillus mixture the most inhibitory against E. coli. Mixtures were not significantly more inhibitory than single strains. In the broth inhibition assays, all probiotic supernatants inhibited both pathogens when pH was not controlled, with only 2 treatments causing inhibition at a neutral pH. Both viable cells of probiotics and supernatants of probiotic cultures were able to inhibit growth of two urinary tract pathogens. Probiotic mixtures prevented the growth of urinary tract pathogens but were not significantly more inhibitory than single strains. Probiotics appear to produce metabolites that are inhibitory towards urinary tract pathogens. Probiotics display potential to reduce the incidence of urinary tract infections via inhibition of colonisation.

  7. Selection of aggressive pathogenic and solopathogenic strains of Ustilago maydis to improve Huitlacoche production

    Directory of Open Access Journals (Sweden)

    Porfirio Raúl Galicia-García

    Full Text Available ABSTRACT Ustilago maydis is a basidiomycete known as the causative agent of 'common smut', worldwide disease of maize that is recognized by the galls it forms, which have considerable potential as a gourmet food. Results of infection are quite variable, even under optimal greenhouse conditions. In order to find pathogenic strains able to be used as a highly infective and stable inoculum for the successful production of galls either in greenhouses or in the field, ears with gall symptoms containing teliospores were recovered from maize plants. The teliospores were suspended in water and plated on nutrient-rich medium. Twenty-six colonies developed, containing three types of yeast-like colonies: saprotrophic, pathogenic, and solopathogenic. DAPI staining confirmed the presence of solopathogenic strains with diploid sporidia. Groups of different mating types were found when pairs of the 26 strains were arranged resembling partial-diallel combinations. Amplification of the partial b locus revealed that the strains found harbor the alleles b3 and b4, allowing the formation in dikaryotic strains of heterodimeric regulatory proteins associated with fungal development and pathogenicity. In this study, we isolated compatible haploid and solopathogenic diploid strains for their high capacity for inducing smut.

  8. A strain of Serratia marcescens pathogenic for larvae of Lymantria dispar: Infectivity and mechanisms of pathogenicity

    Science.gov (United States)

    J.D. Podgwaite; B.J. Cosenza

    1976-01-01

    The ED50 of a strain of Serratia marcescens for microinjected instar III and IV gypsy moth larvae was 7.5 and 14.5 viable cells, respectively. Percentage and rate of mortality were found to be highly variable among replicates of the same instar and between instars in free-feeding bioassays. Mortality in second instar larvae...

  9. Experimental Evaluation of the Pathogenicity of Different Strains of Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Antônio Aurélio Euzébio

    2012-01-01

    Full Text Available The pathogenesis of three different Schistosoma mansoni strains from the Brazilian states of Minas Gerais (BH strain and São Paulo (SJ and SD strains was evaluated in experimentally infected mice. Observations of the most severe clinical cases among local patients treated (SD strain in the city of Campinas (São Paulo, Brazil formed the basis of this study. Mice were used as definitive hosts and were infected with cercariae from Biomphalaria tenagophila (SJ and SD strains and Biomphalaria glabrata (BH strains. The parameters analyzed were as follows: number of S. mansoni eggs in mice feces; number of granulomas per tissue area in liver, spleen, lungs, pancreas, and ascending colon; measurements of hepatic and intestinal granulomas; number of adult worms; and measurements of trematode eggs. The comparison among the three strains indicated that the SD strain, isolated in Campinas, presented a higher worm recovery relative to the number of penetrating cercariae. In addition, when compared to the SJ and BH strains, the SD strain demonstrated similar pathogenicity to the BH strain, with a greater quantity of granulomas in the viscera, as well as larger granulomas and eggs. Furthermore, a greater quantity of trematode eggs was also shed in the feces.

  10. Three promising fungal strains pathogenic to fruit flies

    Energy Technology Data Exchange (ETDEWEB)

    Jiji, T.; Praveena, R.; Babu, Kavitha; Naseema, A.; Anitha, N. [College of Agriculture, Kerala (India)

    2006-07-01

    Pathogenicity of the fungi Paecilomyces lilacinus, isolated from Bactrocera cucurbitae, and Aspergillus candidus, isolated from B. dorsalis, was tested. Cross infectivity of P. lilacinus on B. dorsalis and A. candidus on B. cucurbitae and cross infectivity of a local isolate of B. bassiana from bhindi leaf roller (Sylepta derogata) on fruit flies (B. cucurbitae and B. dorsalis ) were also studied. These fungi were new records in these hosts. P. lilacinus at 109 spores / ml caused 96.67% and 100 % cumulative mortality in fruit flies on the second and on the third days. LC50 values of P. lilacinus on B. cucurbitae were 5.0 x 106, 8.0 x 105, 7.0 x 105 spores/ ml on second, third and fourth day, respectively. The fungus was found to cross infect B. dorsalis. LC50 values of A. candidus on B. cucurbitae were 1.29 x 108, 1.22 x 107, 2.27 x 106 spores / ml on third, fourth and fifth day, respectively. The fungus was found to be cross infective to B. cucurbitae. B. bassiana at 109 spores/ ml on B. dorsalis was found to cause 70%, 80% and 90% mortality on fourth, fifth and sixth day. LC50 values of B. bassiana on B. dorsalis were 7.0 x 108, 2.0 x 107, 5.0 x 106 spores/ ml on third, fourth and fifth day ,respectively . Formulation of P. lilacinus as wettable powder and granules and B. bassiana as wettable powder, were also prepared and their efficacy was tested on hosts. (author)

  11. Three promising fungal strains pathogenic to fruit flies

    International Nuclear Information System (INIS)

    Jiji, T.; Praveena, R.; Babu, Kavitha; Naseema, A.; Anitha, N.

    2006-01-01

    Pathogenicity of the fungi Paecilomyces lilacinus, isolated from Bactrocera cucurbitae, and Aspergillus candidus, isolated from B. dorsalis, was tested. Cross infectivity of P. lilacinus on B. dorsalis and A. candidus on B. cucurbitae and cross infectivity of a local isolate of B. bassiana from bhindi leaf roller (Sylepta derogata) on fruit flies (B. cucurbitae and B. dorsalis ) were also studied. These fungi were new records in these hosts. P. lilacinus at 109 spores / ml caused 96.67% and 100 % cumulative mortality in fruit flies on the second and on the third days. LC50 values of P. lilacinus on B. cucurbitae were 5.0 x 106, 8.0 x 105, 7.0 x 105 spores/ ml on second, third and fourth day, respectively. The fungus was found to cross infect B. dorsalis. LC50 values of A. candidus on B. cucurbitae were 1.29 x 108, 1.22 x 107, 2.27 x 106 spores / ml on third, fourth and fifth day, respectively. The fungus was found to be cross infective to B. cucurbitae. B. bassiana at 109 spores/ ml on B. dorsalis was found to cause 70%, 80% and 90% mortality on fourth, fifth and sixth day. LC50 values of B. bassiana on B. dorsalis were 7.0 x 108, 2.0 x 107, 5.0 x 106 spores/ ml on third, fourth and fifth day ,respectively . Formulation of P. lilacinus as wettable powder and granules and B. bassiana as wettable powder, were also prepared and their efficacy was tested on hosts. (author)

  12. Competition of pathogen strains leading to infection with variable infectivity and the effect of treatment

    NARCIS (Netherlands)

    Xiridou, Maria; Kretzschmar, Mirjam; Geskus, Ronald

    2005-01-01

    A model for the spread of two strains of a pathogen leading to an infection with variable infectivity is considered. The course of infection is described by two stages with different infectivity levels. The model is extended to account for treatment by including a third stage with different

  13. Draft Genome Sequence of the Animal and Human Pathogen Malassezia pachydermatis Strain CBS 1879

    Science.gov (United States)

    Triana, Sergio; González, Andrés; Ohm, Robin A.; Wösten, Han A. B.; de Cock, Hans; Restrepo, Silvia

    2015-01-01

    Malassezia pachydermatis is a basidiomycetous yeast that causes infections in humans and animals. Here, we report the genome sequence of Malassezia pachydermatis strain CBS 1879, which will facilitate the study of mechanisms underlying pathogenicity of the only non-lipid-dependent Malasezzia species. PMID:26472839

  14. A new laboratory cultivation of Paramecium bursaria using non-pathogenic bacteria strains.

    Science.gov (United States)

    Bator, Tomasz

    2010-01-01

    In most studies dealing with the laboratory cultivation of paramecia (Paramecium bursaria), Klebsiella pneumoniae bacteria are used to inoculate the medium. However, Klebsiella pneumoniae is a typical pathogen, and its use is always associated with a risk of infection. The aim of the present research was to examine non-pathogenic bacteria strains as components of the medium for Paramecium bursaria. The paramecia were incubated on lettuce infusions bacterized with different bacteria strains: Bacillus subtilis DSM 10, Bacillus megaterium DSM 32, Escherichia coli DSM 498, Micrococcus luteus DSM 348. A strain derived from the natural habitat of Paramecium bursaria was used as the control one. Experiments were conducted under constant light and in the dark. Paramecia cells were counted under a stereomicroscope on consecutive days of incubation. The obtained results show that the most intensive growth of Paramecium bursaria occurs in the presence of Escherichia coli DSM 498. The use of this strain as a component of the medium allows one to obtain a high number of ciliates regardless of the light conditions. It can be concluded that the Paramecium bursaria cultivation procedure can be modified by using the non-pathogenic bacteria strain Escherichia coli DSM 498 instead of Klebsiella pneumoniae.

  15. Pathogenic strains of Yersinia enterocolitica isolated from domestic dogs (Canis familiaris) belonging to farmers are of the same subtype as pathogenic Y. enterocolitica strains isolated from humans and may be a source of human infection in Jiangsu Province, China.

    Science.gov (United States)

    Wang, Xin; Cui, Zhigang; Wang, Hua; Tang, Liuying; Yang, Jinchuan; Gu, Ling; Jin, Dong; Luo, Longze; Qiu, Haiyan; Xiao, Yuchun; Xiong, Haiping; Kan, Biao; Xu, Jianguo; Jing, Huaiqi

    2010-05-01

    We isolated 326 Yersinia enterocolitica strains from 5,919 specimens from patients with diarrhea at outpatient clinics, livestock, poultry, wild animals, insect vectors, food, and the environment in the cities of Nantong and Xuzhou in Jiangsu Province, China, from 2004 to 2008. The results showed that the 12 pathogenic strains were of the O:3 serotype. Six strains were isolated from domestic dogs (Canis familiaris) belonging to farmers and were found to be the primary carriers of pathogenic Y. enterocolitica strains, especially in Xuzhou. Pulsed-field gel electrophoresis analysis of the pathogenic strains from dogs belonging to farmers showed that they shared the same patterns as strains from diarrhea patients isolated in 1994. This indicates that the strains from domestic dogs have a close correlation with the strains causing human infections.

  16. Reduction of teat skin mastitis pathogen loads: differences between strains, dips, and contact times.

    Science.gov (United States)

    Enger, B D; Fox, L K; Gay, J M; Johnson, K A

    2015-02-01

    The purpose of these experiments was to (1) assess differences in mastitis pathogen strain sensitivities to teat disinfectants (teat dips), and (2) determine the optimum time for premilking teat dips to remain in contact with teat skin to reduce pathogen loads on teat skin. Two experiments were conducted using the excised teat model. In experiment 1, the differences in mastitis pathogen strain sensitivities to 4 commercially available dips (dip A: 1% H2O2; dip B: 1% chlorine dioxide; dip C: 1% iodophor; and dip D: 0.5% iodophor) were evaluated. Four strains of 11 common mastitis pathogens (Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, Streptococcus dysgalactiae, Streptococcus uberis, Escherichia coli, Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus hyicus, Staphylococcus xylosus, and Staphylococcus haemolyticus) were tested. In experiment 2, the percentage log reduction of mastitis pathogens (Escherichia coli, Streptococcus uberis, Streptococcus dysgalactiae, Klebsiella species, Staphylococcus chromogenes, Staphylococcus haemolyticus, Staphylococcus xylosus, and Staphylococcus epidermidis) on teat skin with 3 commercially available teat dips: dip A; dip D; and dip E: 0.25% iodophor, using dip contact times of 15, 30, and 45 s, was evaluated. Experiment 1 results indicated significant differences in strain sensitivities to dips within pathogen species: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Species differences were also found where Mycoplasma bovis (97.9% log reduction) was the most sensitive to tested teat dips and Staphylococcus haemolyticus (71.4% log reduction) the most resistant. Experiment 2 results indicated that contact times of 30 and 45 s were equally effective in reducing recovered bacteria for dips D and E and were also significantly more effective than a 15-s contact time. No differences were seen in recovered bacteria between tested contact times after treatment with dip

  17. Multiple sample flow through immunomagnetic separator for concentrating pathogenic bacteria

    International Nuclear Information System (INIS)

    Rotariu, Ovidiu; Ogden, Iain D; MacRae, Marion; Udrea, Laura Elena; Strachan, Norval J C

    2005-01-01

    The standard method of immunomagnetic separation for isolating pathogenic bacteria from food and environmental matrices processes 1 ml volumes. Pathogens present at low levels ( 97% recovery of polydisperse magnetic particles (diameter range 1 to 8 μm) containing 29-33% w/w Fe 3 O 4 content. Between 70 and 130 times more of the pathogenic bacteria Escherichia coli O157 is recovered from PBS compared with the standard 1 ml method. Also, the recovery of E. coli O157 from beef mince homogenates, after a 4 h incubation at 42 deg. C, is between 80 and 180 times higher than the standard 1 ml method

  18. A replicative plasmid vector allows efficient complementation of pathogenic Leptospira strains.

    Science.gov (United States)

    Pappas, Christopher J; Benaroudj, Nadia; Picardeau, Mathieu

    2015-05-01

    Leptospirosis, an emerging zoonotic disease, remains poorly understood because of a lack of genetic manipulation tools available for pathogenic leptospires. Current genetic manipulation techniques include insertion of DNA by random transposon mutagenesis and homologous recombination via suicide vectors. This study describes the construction of a shuttle vector, pMaORI, that replicates within saprophytic, intermediate, and pathogenic leptospires. The shuttle vector was constructed by the insertion of a 2.9-kb DNA segment including the parA, parB, and rep genes into pMAT, a plasmid that cannot replicate in Leptospira spp. and contains a backbone consisting of an aadA cassette, ori R6K, and oriT RK2/RP4. The inserted DNA segment was isolated from a 52-kb region within Leptospira mayottensis strain 200901116 that is not found in the closely related strain L. mayottensis 200901122. Because of the size of this region and the presence of bacteriophage-like proteins, it is possible that this region is a result of a phage-related genomic island. The stability of the pMaORI plasmid within pathogenic strains was tested by passaging cultures 10 times without selection and confirming the presence of pMaORI. Concordantly, we report the use of trans complementation in the pathogen Leptospira interrogans. Transformation of a pMaORI vector carrying a functional copy of the perR gene in a null mutant background restores the expression of PerR and susceptibility to hydrogen peroxide comparable to that of wild-type cells. In conclusion, we demonstrate the replication of a stable plasmid vector in a large panel of Leptospira strains, including pathogens. The shuttle vector described will expand our ability to perform genetic manipulation of Leptospira spp. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  19. Molecular Typing of Pathogenic Leptospira Serogroup Icterohaemorrhagiae Strains Circulating in China during the Past 50 Years

    Science.gov (United States)

    Zhang, Cuicai; Yang, Huimian; Li, Xiuwen; Cao, Zhiqiang; Zhou, Haijian; Zeng, Linzi; Xu, Jianmin; Xu, Yinghua; Chang, Yung-Fu; Guo, Xiaokui; Zhu, Yongzhang; Jiang, Xiugao

    2015-01-01

    Background Leptospirosis is one of the most important neglected tropical infectious diseases worldwide. Icterohaemorrhagiae has been throughout recent history, and still is, the predominant serogroup of this pathogen in China. However, very little in detail is known about the serovars or genotypes of this serogroup. Methodology/Principal Findings In this study, 120 epidemic strains from five geographically diverse regions in China collected over a 50 year period (1958~2008), and 8 international reference strains characterized by 16S rRNA sequencing and MLST analysis. 115, 11 and 2 strains were identified as L. interrogans, L. borgpetersenii, and L. kirschneri, respectively. 17 different STs were identified including 69 ST1 strains, 18 ST17, 18 ST128, 9 ST143 and 2 ST209. The remaining 12 strains belonged to 12 different STs. eBURST analysis demonstrated that, among the clonal complexes isolated (CCs), CC1 accounted for 73.3% (88/120) strains representing three STs: ST1, ST128 and ST98. ST1 was the most likely ancestral strain of this CC, followed by singleton CC17 (17/120) and CC143 (11/120). Further analysis of adding 116 serogroup Icterohaemorrhagiae strains in the MLST database and studies previously described using global eBURST analysis and MST dendrogram revealed relatively similar ST clustering patterns with five main CCs and 8 singletons among these 244 strains. CC17 was found to be the most prevalent clone of pathogenic Leptospira circulating worldwide. This is the first time, to our knowledge, that ST1 and ST17 strains were distributed among 4 distinct serovars, indicating a highly complicated relationship between serovars and STs. Conclusions/Significance Our studies demonstrated a high level of genetic diversity in the serogroup Icterohaemorrhagiae strains. Distinct from ST17 or ST37 circulating elsewhere, ST1 included in CC1, has over the past 50 years or so, proven to be the most prevalent ST of pathogenic leptospires isolated in China. Moreover, the

  20. Genetic Diversity of Tick-Borne Rickettsial Pathogens; Insights Gained from Distant Strains

    Directory of Open Access Journals (Sweden)

    Sebastián Aguilar Pierlé

    2014-01-01

    Full Text Available The ability to capture genetic variation with unprecedented resolution improves our understanding of bacterial populations and their ability to cause disease. The goal of the pathogenomics era is to define genetic diversity that results in disease. Despite the economic losses caused by vector-borne bacteria in the Order Rickettsiales, little is known about the genetic variants responsible for observed phenotypes. The tick-transmitted rickettsial pathogen Anaplasma marginale infects cattle in tropical and subtropical regions worldwide, including Australia. Genomic analysis of North American A. marginale strains reveals a closed core genome defined by high levels of Single Nucleotide Polymorphisms (SNPs. Here we report the first genome sequences and comparative analysis for Australian strains that differ in virulence and transmissibility. A list of genetic differences that segregate with phenotype was evaluated for the ability to distinguish the attenuated strain from virulent field strains. Phylogenetic analyses of the Australian strains revealed a marked evolutionary distance from all previously sequenced strains. SNP analysis showed a strikingly reduced genetic diversity between these strains, with the smallest number of SNPs detected between any two A. marginale strains. The low diversity between these phenotypically distinct bacteria presents a unique opportunity to identify the genetic determinants of virulence and transmission.

  1. Comparative genomic analyses of Mycoplasma hyopneumoniae pathogenic 168 strain and its high-passaged attenuated strain

    Science.gov (United States)

    2013-01-01

    Background Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia (EP), a mild, chronic pneumonia of swine. Despite presenting with low direct mortality, EP is responsible for major economic losses in the pig industry. To identify the virulence-associated determinants of M. hyopneumoniae, we determined the whole genome sequence of M. hyopneumoniae strain 168 and its attenuated high-passage strain 168-L and carried out comparative genomic analyses. Results We performed the first comprehensive analysis of M. hyopneumoniae strain 168 and its attenuated strain and made a preliminary survey of coding sequences (CDSs) that may be related to virulence. The 168-L genome has a highly similar gene content and order to that of 168, but is 4,483 bp smaller because there are 60 insertions and 43 deletions in 168-L. Besides these indels, 227 single nucleotide variations (SNVs) were identified. We further investigated the variants that affected CDSs, and compared them to reported virulence determinants. Notably, almost all of the reported virulence determinants are included in these variants affected CDSs. In addition to variations previously described in mycoplasma adhesins (P97, P102, P146, P159, P216, and LppT), cell envelope proteins (P95), cell surface antigens (P36), secreted proteins and chaperone protein (DnaK), mutations in genes related to metabolism and growth may also contribute to the attenuated virulence in 168-L. Furthermore, many mutations were located in the previously described repeat motif, which may be of primary importance for virulence. Conclusions We studied the virulence attenuation mechanism of M. hyopneumoniae by comparative genomic analysis of virulent strain 168 and its attenuated high-passage strain 168-L. Our findings provide a preliminary survey of CDSs that may be related to virulence. While these include reported virulence-related genes, other novel virulence determinants were also detected. This new information will form

  2. Multiple Origins of the Pathogenic Yeast Candida orthopsilosis by Separate Hybridizations between Two Parental Species.

    Science.gov (United States)

    Schröder, Markus S; Martinez de San Vicente, Kontxi; Prandini, Tâmara H R; Hammel, Stephen; Higgins, Desmond G; Bagagli, Eduardo; Wolfe, Kenneth H; Butler, Geraldine

    2016-11-01

    Mating between different species produces hybrids that are usually asexual and stuck as diploids, but can also lead to the formation of new species. Here, we report the genome sequences of 27 isolates of the pathogenic yeast Candida orthopsilosis. We find that most isolates are diploid hybrids, products of mating between two unknown parental species (A and B) that are 5% divergent in sequence. Isolates vary greatly in the extent of homogenization between A and B, making their genomes a mosaic of highly heterozygous regions interspersed with homozygous regions. Separate phylogenetic analyses of SNPs in the A- and B-derived portions of the genome produces almost identical trees of the isolates with four major clades. However, the presence of two mutually exclusive genotype combinations at the mating type locus, and recombinant mitochondrial genomes diagnostic of inter-clade mating, shows that the species C. orthopsilosis does not have a single evolutionary origin but was created at least four times by separate interspecies hybridizations between parents A and B. Older hybrids have lost more heterozygosity. We also identify two isolates with homozygous genomes derived exclusively from parent A, which are pure non-hybrid strains. The parallel emergence of the same hybrid species from multiple independent hybridization events is common in plant evolution, but is much less documented in pathogenic fungi.

  3. Multiple Origins of the Pathogenic Yeast Candida orthopsilosis by Separate Hybridizations between Two Parental Species.

    Directory of Open Access Journals (Sweden)

    Markus S Schröder

    2016-11-01

    Full Text Available Mating between different species produces hybrids that are usually asexual and stuck as diploids, but can also lead to the formation of new species. Here, we report the genome sequences of 27 isolates of the pathogenic yeast Candida orthopsilosis. We find that most isolates are diploid hybrids, products of mating between two unknown parental species (A and B that are 5% divergent in sequence. Isolates vary greatly in the extent of homogenization between A and B, making their genomes a mosaic of highly heterozygous regions interspersed with homozygous regions. Separate phylogenetic analyses of SNPs in the A- and B-derived portions of the genome produces almost identical trees of the isolates with four major clades. However, the presence of two mutually exclusive genotype combinations at the mating type locus, and recombinant mitochondrial genomes diagnostic of inter-clade mating, shows that the species C. orthopsilosis does not have a single evolutionary origin but was created at least four times by separate interspecies hybridizations between parents A and B. Older hybrids have lost more heterozygosity. We also identify two isolates with homozygous genomes derived exclusively from parent A, which are pure non-hybrid strains. The parallel emergence of the same hybrid species from multiple independent hybridization events is common in plant evolution, but is much less documented in pathogenic fungi.

  4. In vitro antimycobacterial activity and toxicity of eight medicinal plants against pathogenic and nonpathogenic mycobacterial strains.

    Science.gov (United States)

    Nguta, Joseph M; Appiah-Opong, Regina; Nyarko, Alexander K; Yeboah-Manu, Dorothy; Addo, Phyllis G A; Otchere, Isaac Darko; Kissi-Twum, Abena

    2016-12-01

    Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a serious public health challenge towards which new hits are urgently needed. Medicinal plants remains a major source of new ligands against global infectious illnesses. In our laboratories, we are currently investigating locally used ethnobotanicals for novel compounds against zoonotic tuberculosis. The microplate alamar blue assay (MABA) was used to study the anti-TB activity while the CellTiter 96® AQ ueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients (R 2 ) were used to compare the relationship between antimycobacterial activity of the eight crude extracts against nonpathogenic strains and the pathogenic Mycobacterium bovis. Minimum inhibitory concentration (MICs) values indicated that all the eight tested medicinal plant species had activity against all the three tested mycobacterial strains. Minimum inhibitory concentration value as low as 19.5µg/mL was observed against non-pathogenic strains M. bovis. Activity of the crude extracts against M. aurum was the best predictor of natural product activity against the pathogenic Mycobacterium bovis strain, with a correlation coefficient value (R 2 ) of 0.1371. Results obtained from the current study validate, in part, the traditional utilization of the tested medicinal plants against tuberculosis. The unripe fruits from Solanum torvum are a potential source of safe and efficacious anti-TB crude drugs as well as a source for natural compounds that act as new anti-infection agents, and thus deserve further investigation towards development of a new class of molecules with activity against sensitive and drug resistant strains of M. bovis. Copyright © 2016.

  5. In vitro antimycobacterial activity and toxicity of eight medicinal plants against pathogenic and nonpathogenic mycobacterial strains

    Directory of Open Access Journals (Sweden)

    Joseph M Nguta

    2016-01-01

    Full Text Available Tuberculosis (TB caused by Mycobacterium tuberculosis remains a serious public health challenge towards which new hits are urgently needed. Medicinal plants remains a major source of new ligands against global infectious illnesses. In our laboratories, we are currently investigating locally used ethnobotanicals for novel compounds against zoonotic tuberculosis. The microplate alamar blue assay (MABA was used to study the anti-TB activity while the CellTiter 96® AQueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate PMS, was used for cytotoxic studies. Correlation coefficients (R2 were used to compare the relationship between antimycobacterial activity of the eight crude extracts against nonpathogenic strains and the pathogenic Mycobacterium bovis. Minimum inhibitory concentration (MICs values indicated that all the eight tested medicinal plant species had activity against all the three tested mycobacterial strains. Minimum inhibitory concentration value as low as 19.5 μg/mL was observed against non-pathogenic strains M. bovis. Activity of the crude extracts against M. aurum was the best predictor of natural product activity against the pathogenic Mycobacterium bovis strain, with a correlation coefficient value (R2 of 0.1371. Results obtained from the current study validate, in part, the traditional utilization of the tested medicinal plants against tuberculosis. The unripe fruits from Solanum torvum are a potential source of safe and efficacious anti-TB crude drugs as well as a source for natural compounds that act as new anti-infection agents, and thus deserve further investigation towards development of a new class of molecules with activity against sensitive and drug resistant strains of M. bovis.

  6. Differences in fecundity of Eimeria maxima strains exhibiting different levels of pathogenicity in its avian host.

    Science.gov (United States)

    Jenkins, Mark C; Dubey, J P; Miska, Katarzyna; Fetterer, Raymond

    2017-03-15

    Eimeria maxima is one of the most pathogenic species of avian coccidia, yet it is unknown why different E. maxima strains differ in the pathogenic effects they cause in chickens. The purpose of this study was to determine if a more pathogenic E. maxima strain (APU1) was also more fecund than a less pathogenic E. maxima strain (APU2). At identical doses, E. maxima APU1 always produces greater intestinal lesions and lower weight gain compared to E. maxima APU2. Using a dose response study, median and mean intestinal lesion scores in E. maxima APU1-infected chickens were greater by a score of 1-1.5 compared to chickens infected with E. maxima APU2. Likewise, weight gain depression in E. maxima APU1-infected chickens was 20-25% greater (equivalent to 110-130g body weight) than in E. maxima APU2-infected chickens. In order to understand the underlying cause of these observed clinical effects, 120 broiler chicks (5 oocyst levels, 6 replicates/level) were inoculated with various doses of E. maxima APU1 or APU2 oocysts. The dynamics of oocyst shedding was investigated by collecting fecal material every 12h from 114 to 210h post-inoculation (p.i.) and every 24h thereafter from 210 to 306h, and then processed for measuring E. maxima oocyst output. Oocysts were first observed at 138h p.i., and time of peak oocyst production was nearly identical for both E. maxima APU1 and APU2 around 150-162h. Total oocyst production was 1.1-2.6 fold higher at all dose levels for E. maxima APU1 compared to E. maxima APU2, being significantly higher (P<0.05) at the log 1.5 dose level. Other groups of chickens were infected with higher doses of E. maxima APU1 or APU2 oocysts, and intestinal lesions were assessed by histology at 72, 96, 120, and 144h p.i. Although schizonts, gamonts, and oocysts were observed at expected time-points, no obvious differences were noted in lesions induced by the two E. maxima strains. This study showed that the greater fecundity of E. maxima APU1 compared to E

  7. Draft genome sequences of two opportunistic pathogenic strains of Staphylococcus cohnii isolated from human patients.

    Science.gov (United States)

    Mendoza-Olazarán, Soraya; Garcia-Mazcorro, José F; Morfín-Otero, Rayo; Villarreal-Treviño, Licet; Camacho-Ortiz, Adrián; Rodríguez-Noriega, Eduardo; Bocanegra-Ibarias, Paola; Maldonado-Garza, Héctor J; Dowd, Scot E; Garza-González, Elvira

    2017-01-01

    Herein, we report the draft-genome sequences and annotation of two opportunistic pathogenic strains of Staphylococcus cohnii isolated from humans. One strain (SC-57) was isolated from blood from a male patient in May 2006 and the other (SC-532) from a catheter from a male patient in June 2006. Similar to other genomes of Staphylococcus species, most genes (42%) of both strains are involved in metabolism of amino acids and derivatives, carbohydrates and proteins. Eighty (4%) genes are involved in virulence, disease, and defense and both species show phenotypic low biofilm production and evidence of increased antibiotic resistance associated to biofilm production. From both isolates, a new Staphylococcal Cassette Chromosome mec was detected: mec class A, ccr type 1. This is the first report of whole genome sequences of opportunistic S. cohnii isolated from human patients.

  8. Sequencing and generation of an infectious clone of the pathogenic goose parvovirus strain LH.

    Science.gov (United States)

    Wang, Jianye; Duan, Jinkun; Zhu, Liqian; Jiang, Zhiwei; Zhu, Guoqiang

    2015-03-01

    In this study, the complete genome of the virulent strain LH of goose parvovirus (GPV) was sequenced and cloned into the pBluescript II (SK) plasmid vector. Sequence alignments of the inverted terminal repeats (ITR) of GPV strains revealed a common 14-nt-pair deletion in the stem of the palindromic structure in the LH strain and three other strains isolated after 1982 when compared to three GPV strains isolated earlier than that time. Transfection of 11-day-old embryonated goose eggs with the plasmid pLH, which contains the entire genome of strain LH, resulted in successful rescue of the infectious virus. Death of embryos after transfection via the chorioallantoic membrane infiltration route occurred earlier than when transfection was done via the allantoic cavity inoculation route. The rescued virus exhibited virulence similar to that of its parental virus, as evaluated by the mortality rate in goslings. Generation of the pathogenic infectious clone provides us with a powerful tool to elucidate the molecular pathogenesis of GPV in the future.

  9. Pathogenicity of Salmonella Strains Isolated from Egg Shells and the Layer Farm Environment in Australia

    Science.gov (United States)

    McWhorter, Andrea R.; Davos, Dianne

    2014-01-01

    In Australia, the egg industry is periodically implicated during outbreaks of Salmonella food poisoning. Salmonella enterica serovar Typhimurium and other nontyphoidal Salmonella spp., in particular, are a major concern for Australian public health. Several definitive types of Salmonella Typhimurium strains, but primarily Salmonella Typhimurium definitive type 9 (DT9), have been frequently reported during egg-related food poisoning outbreaks in Australia. The aim of the present study was to generate a pathogenicity profile of nontyphoidal Salmonella isolates obtained from Australian egg farms. To achieve this, we assessed the capacity of Salmonella isolates to cause gastrointestinal disease using both in vitro and in vivo model systems. Data from in vitro experiments demonstrated that the invasion capacity of Salmonella serovars cultured to stationary phase (liquid phase) in LB medium was between 90- and 300-fold higher than bacterial suspensions in normal saline (cultured in solid phase). During the in vivo infection trial, clinical signs of infection and mortality were observed only for mice infected with either 103 or 105 CFU of S. Typhimurium DT9. No mortality was observed for mice infected with Salmonella serovars with medium or low invasive capacity in Caco-2 cells. Pathogenicity gene profiles were also generated for all serovars included in this study. The majority of serovars tested were positive for selected virulence genes. No relationship between the presence or absence of virulence genes by PCR and either in vitro invasive capacity or in vivo pathogenicity was detected. Our data expand the knowledge of strain-to-strain variation in the pathogenicity of Australian egg industry-related Salmonella spp. PMID:25362057

  10. Potential probiotic characteristics of Lactobacillus and Enterococcus strains isolated from traditional dadih fermented milk against pathogen intestinal colonization.

    Science.gov (United States)

    Collado, M Carmen; Surono, Ingrid S; Meriluoto, Jussi; Salminen, Seppo

    2007-03-01

    Traditional fermented buffalo milk in Indonesia (dadih) has been believed to have a beneficial impact on human health, which could be related to the properties of the lactic acid bacteria (LAB) involved in its fermentation process. In previous studies, it was discovered that strains of dadih lactic isolates possessed some beneficial properties in vitro. In the present study, the adhesion capacity of specific LAB isolates from dadih to intestinal mucus was analyzed. Further, the ability to inhibit model human pathogens and displace them from mucus was assessed. The adhesion of tested LAB strains was strain-dependent and varied from 1.4 to 9.8%. The most adhesive Lactobacillus plantarum strain was IS-10506, with 9.8% adhesion. The competition assay between dadih LAB isolates and pathogens showed that a 2-h preincubation with L. plantarum at 37 degrees C significantly reduced pathogen adhesion to mucus. All tested LAB strains displaced and inhibited pathogen adhesion, but the results were strain-specific and dependent on time and pathogen strains. In general, L. plantarum IS-10506 showed the best ability against pathogen adhesion.

  11. Characterization of multiple antibiotic resistant clinical strains of Staphylococcus isolated from pregnant women vagina.

    Science.gov (United States)

    Hetsa, Bakwena Ashton; Kumar, Ajay; Ateba, Collins Njie

    2018-03-29

    Vagina which is one of the important reservoirs for Staphylococcus and in pregnant women pathogenic strains may infect the child during the birth or by vertical transmission. A total of 68 presumptive Staphylococcus strains isolated from human vagina were found to be gram-positive cocci, and only 32 (47%) isolates were found beta-hemolytic. Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) results confirmed 33 isolates belonged to Staphylococcus which consisting of 6 species, i.e., S. aureus (14), S. vitulinus (7), S. epidermidis (4), S cohnii (3), S. equorum (3), and S. succinus (2). Further, the result of antibiotic susceptibility tests showed that large proportions (76%-100%) of the isolates were resistant to multiple antibiotics and more often resistant to penicillin (100%), ampicillin (100%), oxacillin (97%), oxytetracycline (97%), vancomycin (97%), rifampin (85%), erythromycin (82%), and streptomycin (76%). In the present study, only the sec enterotoxin gene was detected in four S. aureus strains. DNA fingerprints of the 33 isolates that were generated using random amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC) PCR analysis revealed great genetic relatedness of isolates. High prevalence of vaginal colonization with multiple antibiotic-resistant staphylococci among pregnant women was observed which were emerged from the single respective species clones that underwent evolution. The vertical transmission of these multiple antibiotic-resistant Staphylococcus species to the infant is possible; therefore, the findings of this study emphasize the need for regular surveillance of antibiotic-resistant bacterial strains in pregnant women in this area.

  12. R5 strains of human immunodeficiency virus type 1 from rapid progressors lacking X4 strains do not possess X4-type pathogenicity in human thymus

    NARCIS (Netherlands)

    Berkowitz, R. D.; van't Wout, A. B.; Kootstra, N. A.; Moreno, M. E.; Linquist-Stepps, V. D.; Bare, C.; Stoddart, C. A.; Schuitemaker, H.; McCune, J. M.

    1999-01-01

    Some individuals infected with only R5 strains of human immunodeficiency virus type 1 progress to AIDS as quickly as individuals harboring X4 strains. We determined that three R5 viruses were much less pathogenic than an X4 virus in SCID-hu Thy/Liv mice, suggesting that R5 virus-mediated rapid

  13. Antagonistic Potential of Native Trichoderma viride Strain against Potent Tea Fungal Pathogens in North East India.

    Science.gov (United States)

    Naglot, A; Goswami, S; Rahman, I; Shrimali, D D; Yadav, Kamlesh K; Gupta, Vikas K; Rabha, Aprana Jyoti; Gogoi, H K; Veer, Vijay

    2015-09-01

    Indigenous strains of Trichoderma species isolated from rhizosphere soils of Tea gardens of Assam, north eastern state of India were assessed for in vitro antagonism against two important tea fungal pathogens namely Pestalotia theae and Fusarium solani. A potent antagonist against both tea pathogenic fungi, designated as SDRLIN1, was selected and identified as Trichoderma viride. The strain also showed substantial antifungal activity against five standard phytopathogenic fungi. Culture filtrate collected from stationary growth phase of the antagonist demonstrated a significantly higher degree of inhibitory activity against all the test fungi, demonstrating the presence of an optimal blend of extracellular antifungal metabolites. Moreover, quantitative enzyme assay of exponential and stationary culture filtrates revealed that the activity of cellulase, β-1,3-glucanase, pectinase, and amylase was highest in the exponential phase, whereas the activity of proteases and chitinase was noted highest in the stationary phase. Morphological changes such as hyphal swelling and distortion were also observed in the fungal pathogen grown on potato dextrose agar containing stationary phase culture filtrate. Moreover, the antifungal activity of the filtrate was significantly reduced but not entirely after heat or proteinase K treatment, demonstrating substantial role of certain unknown thermostable antifungal compound(s) in the inhibitory activity.

  14. Antagonistic Potential of Native Trichoderma viride Strain against Potent Tea Fungal Pathogens in North East India

    Directory of Open Access Journals (Sweden)

    A. Naglot

    2015-09-01

    Full Text Available Indigenous strains of Trichoderma species isolated from rhizosphere soils of Tea gardens of Assam, north eastern state of India were assessed for in vitro antagonism against two important tea fungal pathogens namely Pestalotia theae and Fusarium solani. A potent antagonist against both tea pathogenic fungi, designated as SDRLIN1, was selected and identified as Trichoderma viride. The strain also showed substantial antifungal activity against five standard phytopathogenic fungi. Culture filtrate collected from stationary growth phase of the antagonist demonstrated a significantly higher degree of inhibitory activity against all the test fungi, demonstrating the presence of an optimal blend of extracellular antifungal metabolites. Moreover, quantitative enzyme assay of exponential and stationary culture filtrates revealed that the activity of cellulase, β-1,3-glucanase, pectinase, and amylase was highest in the exponential phase, whereas the activity of proteases and chitinase was noted highest in the stationary phase. Morphological changes such as hyphal swelling and distortion were also observed in the fungal pathogen grown on potato dextrose agar containing stationary phase culture filtrate. Moreover, the antifungal activity of the filtrate was significantly reduced but not entirely after heat or proteinase K treatment, demonstrating substantial role of certain unknown thermostable antifungal compound(s in the inhibitory activity.

  15. Phylogenetic analysis, fumonisin production and pathogenicity of Fusarium fujikuroi strains isolated from rice in the Philippines.

    Science.gov (United States)

    Cruz, Alejandra; Marín, Patricia; González-Jaén, M Teresa; Aguilar, Kristel Grace I; Cumagun, Christian Joseph R

    2013-09-01

    Fusarium fujikuroi Nirenberg is a maize and rice pathogen causing important agricultural losses and produces fumonisins - mycotoxins which pose health risk to humans and farm animals. However, little information is available about the phylogenetics of this species and its ability to produce fumonisins in rice. We studied 32 strains isolated from rice in the Philippines and performed a phylogenetic analysis using the partial sequence of Elongation Factor 1 alpha (EF-1α) including isolates belonging to closely related species. Fumonisin B1 (FB1 ) production was analyzed in 7-day-old cultures grown in fumonisin-inducing medium by an enzyme-linked immunosorbent assay-based method and by real-time reverse transcriptase-polymerase chain reaction using primers for FUM1 gene, a key gene in fumonisin biosynthesis. Nucleotide diversities per site (π) were 0.00024 ± 0.00022 (standard deviation) for the 32 F. fujikuroi strains from the Philippines and 0.00189 ± 0.00143 for all 34 F. fujikuroi strains, respectively. F. fujikuroi isolates grouped into one cluster separated from the rest of isolates belonging to the closely related F. proliferatum and showed very low variability, irrespective of their geographic origin. The cluster containing strains of F. proliferatum showed higher intraspecific variability than F. fujikuroi. Thirteen of the 32 strains analyzed were FB1 producers (40.62%), with production ranging from 0.386 to 223.83 ppm. All isolates analyzed showed FUM1 gene expression above 1 and higher than the CT value of the non-template control sample. Both seedling stunting and elongation were induced by the isolates in comparison with the control. F. fujikuroi are distinct from F. proliferatum isolates based on phytogenetic analysis and are potential fumonisin producers because all are positive for FUM1 gene expression. No relationship between fumonisin production and pathogenicity could be observed. © 2013 Society of Chemical Industry.

  16. Antifungal susceptibility profiles of 1698 yeast reference strains revealing potential emerging human pathogens.

    Directory of Open Access Journals (Sweden)

    Marie Desnos-Ollivier

    Full Text Available New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes. Interestingly, geometric mean minimum inhibitory concentrations (MICs of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001. Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically "resistant" to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens.

  17. Pathogenicity of a Very Virulent Strain of Marek's Disease Herpesvirus Cloned as Infectious Bacterial Artificial Chromosomes

    Directory of Open Access Journals (Sweden)

    Lorraine P. Smith

    2011-01-01

    Full Text Available Bacterial artificial chromosome (BAC vectors containing the full-length genomes of several herpesviruses have been used widely as tools to enable functional studies of viral genes. Marek's disease viruses (MDVs are highly oncogenic alphaherpesviruses that induce rapid-onset T-cell lymphomas in chickens. Oncogenic strains of MDV reconstituted from BAC clones have been used to examine the role of viral genes in inducing tumours. Past studies have demonstrated continuous increase in virulence of MDV strains. We have previously reported on the UK isolate C12/130 that showed increased virulence features including lymphoid organ atrophy and enhanced tropism for the central nervous system. Here we report the construction of the BAC clones (pC12/130 of this strain. Chickens were infected with viruses reconstituted from the pC12/130 clones along with the wild-type virus for the comparison of the pathogenic properties. Our studies show that BAC-derived viruses induced disease similar to the wild-type virus, though there were differences in the levels of pathogenicity between individual viruses. Generation of BAC clones that differ in the potential to induce cytolytic disease provide the opportunity to identify the molecular determinants of increased virulence by direct sequence analysis as well as by using reverse genetics approaches on the infectious BAC clones.

  18. Pathogenicity evaluation of twelve West Nile virus strains belonging to four lineages from five continents in a mouse model: discrimination between three pathogenicity categories.

    Science.gov (United States)

    Pérez-Ramírez, Elisa; Llorente, Francisco; Del Amo, Javier; Fall, Gamou; Sall, Amadou Alpha; Lubisi, Alison; Lecollinet, Sylvie; Vázquez, Ana; Jiménez-Clavero, Miguel Ángel

    2017-04-01

    Rodent models have been used extensively to study West Nile virus (WNV) infection because they develop severe neurological symptoms similar to those observed in human WNV neuroinvasive disease. Most of this research has focused on old lineage (L) 1 strains, while information about pathogenicity is lacking for the most recent L1 and L2 strains, as well as for newly defined lineages. In this study, 4-week-old Swiss mice were inoculated with a collection of 12 WNV isolates, comprising 10 old and recent L1 and L2 strains, the putative L6 strain from Malaysia and the proposed L7 strain Koutango (KOU). The intraperitoneal inoculation of 10-fold dilutions of each strain allowed the characterization of the isolates in terms of LD50, median survival times, ID50, replication in neural and extraneural tissues and antibody production. Based on these results, we classified the isolates in three groups: high virulence (all L1a strains, recent L2 strains and KOU), moderate virulence (B956 strain) and low virulence (Kunjin and Malaysian isolates). We determined that the inoculation of a single dose of 1000 p.f.u. would be sufficient to classify WNV strains by pathotype. We confirmed the enhanced virulence of the KOU strain with a high capacity to cause rapid systemic infection. We also corroborated that differences in pathogenicity among strains do not correlate with phylogenetic lineage or geographic origin, and confirmed that recent European and African WNV strains belonging to L1 and L2 are highly virulent and do not differ in their pathotype profile compared to the prototype NY99 strain.

  19. Genome Sequence of the Enterobacter mori Type Strain, LMG 25706, a Pathogenic Bacterium of Morus alba L. ▿

    Science.gov (United States)

    Zhu, Bo; Zhang, Guo-Qing; Lou, Miao-Miao; Tian, Wen-Xiao; Li, Bin; Zhou, Xue-Ping; Wang, Guo-Feng; Liu, He; Xie, Guan-Lin; Jin, Gu-Lei

    2011-01-01

    Enterobacter mori is a plant-pathogenic enterobacterium responsible for the bacterial wilt of Morus alba L. Here we present the draft genome sequence of the type strain, LMG 25706. To the best of our knowledge, this is the first genome sequence of a plant-pathogenic bacterium in the genus Enterobacter. PMID:21602328

  20. Chinese and Vietnamese strains of HP-PRRSV cause different pathogenic outcomes in United States high health swine

    Science.gov (United States)

    An infectious clone of a highly pathogenic PRRSV strain from Vietnam (rSRV07) was prepared, analyzed and compared to Chinese highly pathogenic PRRSV rJXwn06 and US Type 2 prototype VR-2332 in order to examine the effects of virus phenotype and genotype on growth in MARC-145 cells, as well as the imp...

  1. New insights into virulence mechanisms of rice pathogen Acidovorax avenae subsp. avenae strain RS-1 following exposure to ?-lactam antibiotics

    OpenAIRE

    Li, Bin; Ge, Mengyu; Zhang, Yang; Wang, Li; Ibrahim, Muhammad; Wang, Yanli; Sun, Guochang; Chen, Gongyou

    2016-01-01

    Recent research has shown that pathogen virulence can be altered by exposure to antibiotics, even when the growth rate is unaffected. Investigating this phenomenon provides new insights into understanding the virulence mechanisms of bacterial pathogens. This study investigates the phenotypic and transcriptomic responses of the rice pathogenic bacterium Acidovorax avenae subsp. avenae (Aaa) strain RS-1 to ?-lactam antibiotics especially Ampicillin (Amp). Our results indicate that exposure to A...

  2. Spatial self-organization in a multi-strain host–pathogen system

    International Nuclear Information System (INIS)

    Liu, Quan-Xing; Van de Koppel, Johan; Wang, Rong-Hua; Jin, Zhen; Alonso, David

    2010-01-01

    We develop stochastic spatial epidemic models with the competition of two pathogenic strains. The dynamics resulting from different approaches are examined using both non-spatial and spatially explicit models. Our results show that pair approximation, well-mixed ordinary differential equations (ODEs), Gillespie-algorithm-based simulations and spatially explicit models give similar qualitative results. In particular, the temporal evolution of the spatial model can be successfully approximated by pair equations. Simulation results obtained from the spatially explicit model show that, first, mutation plays a major role in multi-strain coexistence, second, mild virulence remarkably decreases the coexistence domain of the parameter space and, third, large-scale self-organized spatial patterns emerge for a wide range of transmission and virulence parameter values, where spatial self-organized clusters reveal a power law behavior within the coexistence domain

  3. Comparative genome analysis of the high pathogenicity Salmonella Typhimurium strain UK-1.

    Directory of Open Access Journals (Sweden)

    Yingqin Luo

    Full Text Available Salmonella enterica serovar Typhimurium, a gram-negative facultative rod-shaped bacterium causing salmonellosis and foodborne disease, is one of the most common isolated Salmonella serovars in both developed and developing nations. Several S. Typhimurium genomes have been completed and many more genome-sequencing projects are underway. Comparative genome analysis of the multiple strains leads to a better understanding of the evolution of S. Typhimurium and its pathogenesis. S. Typhimurium strain UK-1 (belongs to phage type 1 is highly virulent when orally administered to mice and chickens and efficiently colonizes lymphoid tissues of these species. These characteristics make this strain a good choice for use in vaccine development. In fact, UK-1 has been used as the parent strain for a number of nonrecombinant and recombinant vaccine strains, including several commercial vaccines for poultry. In this study, we conducted a thorough comparative genome analysis of the UK-1 strain with other S. Typhimurium strains and examined the phenotypic impact of several genomic differences. Whole genomic comparison highlights an extremely close relationship between the UK-1 strain and other S. Typhimurium strains; however, many interesting genetic and genomic variations specific to UK-1 were explored. In particular, the deletion of a UK-1-specific gene that is highly similar to the gene encoding the T3SS effector protein NleC exhibited a significant decrease in oral virulence in BALB/c mice. The complete genetic complements in UK-1, especially those elements that contribute to virulence or aid in determining the diversity within bacterial species, provide key information in evaluating the functional characterization of important genetic determinants and for development of vaccines.

  4. The ability of algal organic matter and surface runoff to promote the abundance of pathogenic and non-pathogenic strains of Vibrio parahaemolyticus in Long Island Sound, USA.

    Directory of Open Access Journals (Sweden)

    Jake D Thickman

    Full Text Available Food safety is a major concern in the shellfish industry, as severe illness can result from consuming shellfish that have accumulated waterborne pathogens. Shellfish harvesting areas are typically monitored for indicator bacteria such as fecal coliforms that serve as proxies for enteric pathogens although these indicators have shown little relation to some naturally occurring pathogenic bacteria such as Vibrio parahaemolyticus. To examine the dynamics and ecology of pathogenic and non-pathogenic strains of V. parahaemolyticus and address the relevance of indicator bacteria in predicting V. parahaemolyticus concentrations, field surveys and experiments were carried out in western Long Island Sound, NY, USA, a region that has experienced recent outbreaks of shellfish contaminated with V. parahaemolyticus. Pathogenic and non-pathogenic strains were quantified via PCR detection of marker genes and most probable number techniques. Field survey data showed little correspondence between fecal coliforms and V. parahaemolyticus, but significant correlations between V. parahaemolyticus and an alternative indicator, enterococci, and between V. parahaemolyticus and short-term (48 h rainfall were observed. Experiments demonstrated that enrichment of seawater with phytoplankton-derived dissolved organic matter significantly increased the concentration of total V. parahaemolyticus and the presence pathogenic V. parahaemolyticus, but higher temperatures did not. Collectively, these study results suggest that fecal coliforms may fail to account for the full suite of important shellfish pathogens but that enterococci could provide a potential alternative or supplement to shellfish sanitation monitoring. Given the ability of algal-derived dissolved organic matter to promote the growth of pathogenic V. parahaemolyticus, restricting nutrient inputs into coastal water bodies that promote algal blooms may indirectly decrease the proliferation of V. parahaemolyticus

  5. [Screening strains for Trichoderma spp. for strong antagonism against ginseng root pathogens and study on their biological characters].

    Science.gov (United States)

    Zhao, A-Na; Ding, Wan-Long; Zhu, Dian-Long

    2006-10-01

    To screen the Trichodenna spp. for strong antagonist against ginseng root pathogens. The biological characters of ten Trichoderma strains were compared by culturing on different media. And their antagonistic activity against Phytophthora cactorum, Cylindrocarpon destructans and Rhizoctonia solani were measured on PDA. Tv04-2 and Th3080 showed a good growth on soil solution medium and PDA, and also showed high inhibitory efficacy to the three pathogens. The two Trichoderma strains showed different growth rate under light conditions and pH. Trichoderma strains were sensitive to most fungicides used in ginseng root disease controlling, however Tv04-2 was not sensitive to the fungicide Junchong Jueba.

  6. Bactericidal activities of GM flax seedcake extract on pathogenic bacteria clinical strains.

    Science.gov (United States)

    Zuk, Magdalena; Dorotkiewicz-Jach, Agata; Drulis-Kawa, Zuzanna; Arendt, Malgorzata; Kulma, Anna; Szopa, Jan

    2014-07-29

    The antibiotic resistance of pathogenic microorganisms is a worldwide problem. Each year several million people across the world acquire infections with bacteria that are antibiotic-resistant, which is costly in terms of human health. New antibiotics are extremely needed to overcome the current resistance problem. Transgenic flax plants overproducing compounds from phenylpropanoid pathway accumulate phenolic derivatives of potential antioxidative, and thus, antimicrobial activity. Alkali hydrolyzed seedcake extract containing coumaric acid, ferulic acid, caffeic acid, and lignan in high quantities was used as an assayed against pathogenic bacteria (commonly used model organisms and clinical strains). It was shown that the extract components had antibacterial activity, which might be useful as a prophylactic against bacterial infection. Bacteria topoisomerase II (gyrase) inhibition and genomic DNA disintegration are suggested to be the main reason for rendering antibacterial action. The data obtained strongly suggest that the seedcake extract preparation is a suitable candidate for antimicrobial action with a broad spectrum and partial selectivity. Such preparation can be applied in cases where there is a risk of multibacterial infection and excellent answer on global increase in multidrug resistance in pathogenic bacteria.

  7. Diversity and Antagonistic Activity of Actinomycete Strains From Myristica Swamp Soils Against Human Pathogens

    Directory of Open Access Journals (Sweden)

    Varghese Rlnoy

    2014-05-01

    Full Text Available Under the present investigation Actinomycetes were isolated from the soils of Myristica swamps of southern Western Ghats and the antagonistic activity against different human bacterial pathogens was evaluated. Results of the present study revealed that Actinomycetes population in the soils of Myristica swamp was spatially and seasonally varied. Actinomycetes load was varied from 24×104 to 71×103, from 129×103 to 40×103 and from 31×104 to 84×103 in post monsoon, monsoon and pre monsoon respectively. A total of 23 Actinomycetes strains belonging to six genera were isolated from swamp soils. Identification of the isolates showed that most of the isolates belonged to the genus Streptomyces (11, followed by Nocardia (6, Micromonospora (3, Pseudonocardia (1, Streptosporangium (1, and Nocardiopsis (1. Antagonistic studies revealed that 91.3% of Actinomycete isolates were active against one or more tested pathogens, of that 56.52% exhibited activity against Gram negative and 86.95% showed activity against Gram positive bacteria. 39.13% isolates were active against all the bacterial pathogens selected and its inhibition zone diameter was also high. 69.5% of Actinomycetes were exhibited antibacterial activity against Listeria followed by Bacillus cereus (65.21%, Staphylococcus (60.86%, Vibrio cholera (52.17%, Salmonella (52.17% and E. coli (39.13%. The results indicate that the Myristica swamp soils of Southern Western Ghats might be a remarkable reserve of Actinomycetes with potential antagonistic activity.

  8. Control of foodborne pathogens on fresh-cut fruit by a novel strain of Pseudomonas graminis.

    Science.gov (United States)

    Alegre, Isabel; Viñas, Inmaculada; Usall, Josep; Teixidó, Neus; Figge, Marian J; Abadias, Maribel

    2013-06-01

    The consumption of fresh-cut fruit has substantially risen over the last few years, leading to an increase in the number of outbreaks associated with fruit. Moreover, consumers are currently demanding wholesome, fresh-like, safe foods without added chemicals. As a response, the aim of this study was to determine if the naturally occurring microorganisms on fruit are "competitive with" or "antagonistic to" potentially encountered pathogens. Of the 97 and 107 isolates tested by co-inoculation with Escherichia coli O157:H7, Salmonella and Listeria innocua on fresh-cut apple and peach, respectively, and stored at 20 °C, seven showed a strong antagonistic capacity (more than 1-log unit reduction). One of the isolates, CPA-7, achieved the best reduction values (from 2.8 to 5.9-log units) and was the only isolate able to inhibit E. coli O157:H7 at refrigeration temperatures on both fruits. Therefore, CPA-7 was selected for further assays. Dose-response assays showed that CPA-7 should be present in at least the same amount as the pathogen to adequately reduce the numbers of the pathogen. From the results obtained in in vitro assays, competition seemed to be CPA-7's mode of action against E. coli O157:H7. The CPA-7 strain was identified as Pseudomonas graminis. Thus, the results support the potential use of CPA-7 as a bioprotective agent against foodborne pathogens in minimally processed fruit. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. A novel bacteriocin-like substance (BLIS) from a pathogenic strain of Vibrio harveyi.

    Science.gov (United States)

    Prasad, Sathish; Morris, Peter C; Hansen, Rasmus; Meaden, Philip G; Austin, Brian

    2005-09-01

    Inter-strain and inter-species inhibition mediated by a bacteriocin-like inhibitory substance (BLIS) from a pathogenic Vibrio harveyi strain VIB 571 was demonstrated against four isolates of the same species, and one culture each of a Vibrio sp., Vibrio fischeri, Vibrio gazogenes and Vibrio parahaemolyticus. The crude BLIS, which was obtained by ammonium-sulphate precipitation of the cell-free supernatant of a 72 h broth culture of strain VIB 571, was inactivated by lipase, proteinase K, pepsin, trypsin, pronase E, SDS and incubation at > or =60 degrees C for 10 min. The activity was stable between pH 2-11 for at least 5 h. Anion-exchange chromatography, gel filtration, SDS-PAGE and two-dimensional gel electrophoresis revealed the presence of a single major peak, comprising a protein with a pI of approximately 5.4 and a molecular mass of approximately 32 kDa. The N-terminal amino acid sequence of the protein comprised Asp-Glu-Tyr-Ile-Ser-X-Asn-Lys-X-Ser-Ser-Ala-Asp-Ile (with X representing cysteine or modified amino acid residues). A similarity search based on the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) generated peptide masses and the N-terminal sequence did not yield any significant matches.

  10. Comparative pathogenicity of Coxsackievirus A16 circulating and noncirculating strains in vitro and in a neonatal mouse model

    International Nuclear Information System (INIS)

    Huang, L.; Liu, X.; Li, J.L.; Chang, J.L.; Liu, G.C.; Yu, X.F.; Zhang, W.Y.

    2015-01-01

    An enterovirus 71 (EV71) vaccine for the prevention of hand, foot, and mouth disease (HMFD) is available, but it is not known whether the EV71 vaccine cross-protects against Coxsackievirus (CV) infection. Furthermore, although an inactivated circulating CVA16 Changchun 024 (CC024) strain vaccine candidate is effective in newborn mice, the CC024 strain causes severe lesions in muscle and lung tissues. Therefore, an effective CV vaccine with improved pathogenic safety is needed. The aim of this study was to evaluate the in vivo safety and in vitro replication capability of a noncirculating CVA16 SHZH05 strain. The replication capacity of circulating CVA16 strains CC024, CC045, CC090 and CC163 and the noncirculating SHZH05 strain was evaluated by cytopathic effect in different cell lines. The replication capacity and pathogenicity of the CC024 and SHZH05 strains were also evaluated in a neonatal mouse model. Histopathological and viral load analyses demonstrated that the SHZH05 strain had an in vitro replication capacity comparable to the four CC strains. The CC024, but not the SHZH05 strain, became distributed in a variety of tissues and caused severe lesions and mortality in neonatal mice. The differences in replication capacity and in vivo pathogenicity of the CC024 and SHZH05 strains may result from differences in the nucleotide and amino acid sequences of viral functional polyproteins P1, P2 and P3. Our findings suggest that the noncirculating SHZH05 strain may be a safer CV vaccine candidate than the CC024 strain

  11. Comparative pathogenicity of Coxsackievirus A16 circulating and noncirculating strains in vitro and in a neonatal mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L. [Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun (China); The 208th Hospital of PLA, Changchun (China); Liu, X.; Li, J.L.; Chang, J.L.; Liu, G.C. [Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun (China); Yu, X.F. [Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun (China); Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (United States); Zhang, W.Y. [Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun (China)

    2015-03-27

    An enterovirus 71 (EV71) vaccine for the prevention of hand, foot, and mouth disease (HMFD) is available, but it is not known whether the EV71 vaccine cross-protects against Coxsackievirus (CV) infection. Furthermore, although an inactivated circulating CVA16 Changchun 024 (CC024) strain vaccine candidate is effective in newborn mice, the CC024 strain causes severe lesions in muscle and lung tissues. Therefore, an effective CV vaccine with improved pathogenic safety is needed. The aim of this study was to evaluate the in vivo safety and in vitro replication capability of a noncirculating CVA16 SHZH05 strain. The replication capacity of circulating CVA16 strains CC024, CC045, CC090 and CC163 and the noncirculating SHZH05 strain was evaluated by cytopathic effect in different cell lines. The replication capacity and pathogenicity of the CC024 and SHZH05 strains were also evaluated in a neonatal mouse model. Histopathological and viral load analyses demonstrated that the SHZH05 strain had an in vitro replication capacity comparable to the four CC strains. The CC024, but not the SHZH05 strain, became distributed in a variety of tissues and caused severe lesions and mortality in neonatal mice. The differences in replication capacity and in vivo pathogenicity of the CC024 and SHZH05 strains may result from differences in the nucleotide and amino acid sequences of viral functional polyproteins P1, P2 and P3. Our findings suggest that the noncirculating SHZH05 strain may be a safer CV vaccine candidate than the CC024 strain.

  12. Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae.

    Science.gov (United States)

    Pecenková, Tamara; Janda, Martin; Ortmannová, Jitka; Hajná, Vladimíra; Stehlíková, Zuzana; Žárský, Viktor

    2017-09-01

    Selected beneficial Pseudomonas spp. strains have the ability to influence root architecture in Arabidopsis thaliana by inhibiting primary root elongation and promoting lateral root and root hair formation. A crucial role for auxin in this long-term (1week), long-distance plant-microbe interaction has been demonstrated. Arabidopsis seedlings were cultivated in vitro on vertical plates and inoculated with pathogenic strains Pseudomonas syringae pv. maculicola (Psm) and P. syringae pv. tomato DC3000 (Pst), as well as Agrobacterium tumefaciens (Atu) and Escherichia coli (Eco). Root hair lengths were measured after 24 and 48h of direct exposure to each bacterial strain. Several Arabidopsis mutants with impaired responses to pathogens, impaired ethylene perception and defects in the exocyst vesicle tethering complex that is involved in secretion were also analysed. Arabidopsis seedling roots infected with Psm or Pst responded similarly to when infected with plant growth-promoting rhizobacteria; root hair growth was stimulated and primary root growth was inhibited. Other plant- and soil-adapted bacteria induced similar root hair responses. The most compromised root hair growth stimulation response was found for the knockout mutants exo70A1 and ein2. The single immune pathways dependent on salicylic acid, jasmonic acid and PAD4 are not directly involved in root hair growth stimulation; however, in the mutual cross-talk with ethylene, they indirectly modify the extent of the stimulation of root hair growth. The Flg22 peptide does not initiate root hair stimulation as intact bacteria do, but pretreatment with Flg22 prior to Psm inoculation abolished root hair growth stimulation in an FLS2 receptor kinase-dependent manner. These early response phenomena are not associated with changes in auxin levels, as monitored with the pDR5::GUS auxin reporter. Early stimulation of root hair growth is an effect of an unidentified component of living plant pathogenic bacteria. The root

  13. Two new nontoxic, non-pathogenic strains of Sphingomonas elodea for gellan gum production.

    Science.gov (United States)

    Dolan, Laurie C; Matulka, Ray A; LeBeau, Alex L; Boulet, Jamie M

    2016-07-01

    Two new strains of Sphingomonas elodea (designated as PHP1 and PBAD1) were tested for toxicity and pathogenicity in healthy Sprague-Dawley CD(®) IGS rats in separate studies. In each study, twelve rats/sex were administered ≥10(8) viable cells/rat by oral gavage, and four untreated rats/sex served as controls. Blood, feces, and selected organs/tissues collected at various times over the course of the 22 day study were evaluated for the presence of PHP1 or PBAD1 (depending on the study) by a validated method, to determine the potential for survival, propagation, or infectivity of PHP1 and PBAD1 cells in the rat. No mortalities, test substance-related changes in clinical or macroscopic findings, body weight or body weight gain were observed in treated animals compared with controls, indicating a lack of toxicity. PHP1 or PBAD1 were not detected in the tissue, fecal or fluid samples collected from treated animals. Therefore, neither PHP1 nor PBAD1 were pathogenic or acutely toxic under the conditions of the studies. Copyright © 2016. Published by Elsevier Inc.

  14. Draft Genome Sequences of Two Avian Pathogenic Escherichia coli Strains of Clinical Importance, E44 and E51

    DEFF Research Database (Denmark)

    Ronco, Troels; Stegger, Marc; Andersen, Paal S

    2016-01-01

    Avian pathogenic Escherichia coli strains have remarkable impacts on animal welfare and the production economy in the poultry industry worldwide. Here, we present the draft genomes of two isolates from chickens (E44 and E51) obtained from field outbreaks and subsequently investigated for their po......Avian pathogenic Escherichia coli strains have remarkable impacts on animal welfare and the production economy in the poultry industry worldwide. Here, we present the draft genomes of two isolates from chickens (E44 and E51) obtained from field outbreaks and subsequently investigated...

  15. Virulence-related genes, adhesion and invasion of some Yersinia enterocolitica-like strains suggests its pathogenic potential.

    Science.gov (United States)

    Imori, Priscilla F M; Passaglia, Jaqueline; Souza, Roberto A; Rocha, Lenaldo B; Falcão, Juliana P

    2017-03-01

    Yersina enterocolitica-like species have not been extensively studied regarding its pathogenic potential. This work aimed to assess the pathogenic potential of some Y. enterocolitica-like strains by evaluating the presence of virulence-related genes by PCR and their ability to adhere to and invade Caco-2 and HEp-2 cells. A total of 50 Y. frederiksenii, 55 Y. intermedia and 13 Y. kristensenii strains were studied. The strains contained the following genes: Y. frederiksenii, fepA(44%), fes(44%) and ystB(18%); Y. intermedia, ail(53%), fepA (35%), fepD(2%), fes(97%), hreP(2%), ystB(2%) and tccC(35%); Y. kristensenii, ail(62%), ystB(23%), fepA(77%), fepD(54%), fes(54%) and hreP(77%). Generally, the Y. enterocolitica-like strains had a reduced ability to adhere to and invade mammalian cells compared to the highly pathogenic Y. enterocolitica 8081. However, Y. kristensenii FCF410 and Y. frederiksenii FCF461 presented high invasion potentials in Caco-2 cells after five days of pre-incubation increased by 45- and 7.2-fold compared to Y. enterocolitica 8081, respectively; but, the ail gene was not detected in these strains. The presence of virulence-related genes in some of the Y. enterocolitica-like strains indicated their possible pathogenic potential. Moreover, the results suggest the existence of alternative virulence mechanisms and that the pathogenicity of Y. kristensenii and Y. frederiksenii may be strain-dependent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Multiple disease resistance to fungal and oomycete pathogens using a recombinant inbred line population in pepper

    Science.gov (United States)

    Incorporating disease resistance into cultivars is a primary focus of modern breeding programs. Resistance to pathogens is often introgressed from landrace or wild individuals with poor fruit quality into commercial-quality cultivars. Sites of multiple disease resistance (MDR) are regions or “hotspo...

  17. Induction of type I interferon signaling determines the relative pathogenicity of Staphylococcus aureus strains.

    Directory of Open Access Journals (Sweden)

    Dane Parker

    2014-02-01

    Full Text Available The tremendous success of S. aureus as a human pathogen has been explained primarily by its array of virulence factors that enable the organism to evade host immunity. Perhaps equally important, but less well understood, is the importance of the intensity of the host response in determining the extent of pathology induced by S. aureus infection, particularly in the pathogenesis of pneumonia. We compared the pathogenesis of infection caused by two phylogenetically and epidemiologically distinct strains of S. aureus whose behavior in humans has been well characterized. Induction of the type I IFN cascade by strain 502A, due to a NOD2-IRF5 pathway, was the major factor in causing severe pneumonia and death in a murine model of pneumonia and was associated with autolysis and release of peptidogylcan. In contrast to USA300, 502A was readily eliminated from epithelial surfaces in vitro. Nonetheless, 502A caused significantly increased tissue damage due to the organisms that were able to invade systemically and trigger type I IFN responses, and this was ameliorated in Ifnar⁻/⁻ mice. The success of USA300 to cause invasive infection appears to depend upon its resistance to eradication from epithelial surfaces, but not production of specific toxins. Our studies illustrate the important and highly variable role of type I IFN signaling within a species and suggest that targeted immunomodulation of specific innate immune signaling cascades may be useful to prevent the excessive morbidity associated with S. aureus pneumonia.

  18. [Antimycotic activity in vitro and in vivo of 5-fluorocytosine on pathogenic strains of Candida albicans and Cryptococcus neoformans].

    Science.gov (United States)

    Costa, A L; Valenti, A; Costa, G; Calogero, F

    1976-01-01

    The authors have analyzed the 5 Fluoro Cytosine (5FC) activity on strains of Candida albicans and Criptococcus neoformans, both in vitro and in vivo. In vitro the minimal inhibitory concentration (MIC) was determined; in vivo tests of pathogenicity on rabbit and mouse have been executed. The various findings obtained have shown a strong activity of the 5FC on strains of Candida and Criptococcus.

  19. A new zearalenone biodegradation strategy using non-pathogenic Rhodococcus pyridinivorans K408 strain.

    Science.gov (United States)

    Kriszt, Rókus; Krifaton, Csilla; Szoboszlay, Sándor; Cserháti, Mátyás; Kriszt, Balázs; Kukolya, József; Czéh, Arpád; Fehér-Tóth, Szilvia; Török, Lívia; Szőke, Zsuzsanna; Kovács, Krisztina J; Barna, Teréz; Ferenczi, Szilamér

    2012-01-01

    Zearalenone (hereafter referred to as ZEA) is a nonsteroidal estrogenic mycotoxin produced by several Fusarium spp. on cereal grains. ZEA is one of the most hazardous natural endocrine disrupting chemicals (EDC) which induces hyper estrogenic responses in mammals. This can result in reproductive disorders in farm animals as well as in humans. Consequently, detoxification strategies for contaminated crops are crucial for food safety. In this study we have developed a bacterial based detoxification system using a non-pathogen Rhodococcus pyridinivorans K408 strain. Following 5 days treatment of ZEA with R. pyridinivorans K408 strain HPLC analyses showed an 87.21% ZEA-degradation efficiency of the bacterial enzyme systems. In another approach, the strain biotransformation ability has also been confirmed by a bioluminescent version of the yeast estrogen screening system (BLYES), which detected an 81.75% of biodegradability of ZEA, in a good agreement with the chemical analyses. Furthermore, the capacity of R. pyridinivorans to eliminate the estrogenic effects of ZEA was tested by using an immature uterotrophic assay. Prepubertal female rats were treated with vehicle (olive oil), 17β-estradiol, ZEA (0.1-1-5-10 mg/kg body weight) and LB broth containing 500 mg/l ZEA that has already been incubated with or without Rhodococcus pyridinivorans K408 strain. Uterine weights were measured and the mRNA level changes relating to apelin, aquaporin 5, complement component 2, and calbindin-3 genes were measured by qRT-PCR. These genes represent the major pathways that are affected by estromimetic compounds. Zearalenone feeding significantly increased the uterus weight in a dose dependent manner and at the same time upregulated complement component 2 and calbindin-3 expression as well as decreased apelin and aquaporin 5 mRNA levels comparable to that seen in 17β-estradiol exposed rats. In contrast, LB broth in which ZEA was incubated with Rhodococcus pyridinivorans K408 prior to

  20. A new zearalenone biodegradation strategy using non-pathogenic Rhodococcus pyridinivorans K408 strain.

    Directory of Open Access Journals (Sweden)

    Rókus Kriszt

    Full Text Available Zearalenone (hereafter referred to as ZEA is a nonsteroidal estrogenic mycotoxin produced by several Fusarium spp. on cereal grains. ZEA is one of the most hazardous natural endocrine disrupting chemicals (EDC which induces hyper estrogenic responses in mammals. This can result in reproductive disorders in farm animals as well as in humans. Consequently, detoxification strategies for contaminated crops are crucial for food safety. In this study we have developed a bacterial based detoxification system using a non-pathogen Rhodococcus pyridinivorans K408 strain. Following 5 days treatment of ZEA with R. pyridinivorans K408 strain HPLC analyses showed an 87.21% ZEA-degradation efficiency of the bacterial enzyme systems. In another approach, the strain biotransformation ability has also been confirmed by a bioluminescent version of the yeast estrogen screening system (BLYES, which detected an 81.75% of biodegradability of ZEA, in a good agreement with the chemical analyses. Furthermore, the capacity of R. pyridinivorans to eliminate the estrogenic effects of ZEA was tested by using an immature uterotrophic assay. Prepubertal female rats were treated with vehicle (olive oil, 17β-estradiol, ZEA (0.1-1-5-10 mg/kg body weight and LB broth containing 500 mg/l ZEA that has already been incubated with or without Rhodococcus pyridinivorans K408 strain. Uterine weights were measured and the mRNA level changes relating to apelin, aquaporin 5, complement component 2, and calbindin-3 genes were measured by qRT-PCR. These genes represent the major pathways that are affected by estromimetic compounds. Zearalenone feeding significantly increased the uterus weight in a dose dependent manner and at the same time upregulated complement component 2 and calbindin-3 expression as well as decreased apelin and aquaporin 5 mRNA levels comparable to that seen in 17β-estradiol exposed rats. In contrast, LB broth in which ZEA was incubated with Rhodococcus pyridinivorans K

  1. Closely-related Borrelia burgdorferi (sensu stricto) strains exhibit similar fitness in single infections and asymmetric competition in multiple infections.

    Science.gov (United States)

    Rynkiewicz, Evelyn C; Brown, Julia; Tufts, Danielle M; Huang, Ching-I; Kampen, Helge; Bent, Stephen J; Fish, Durland; Diuk-Wasser, Maria A

    2017-02-06

    Wild hosts are commonly co-infected with complex, genetically diverse, pathogen communities. Competition is expected between genetically or ecologically similar pathogen strains which may influence patterns of coexistence. However, there is little data on how specific strains of these diverse pathogen species interact within the host and how this impacts pathogen persistence in nature. Ticks are the most common disease vector in temperate regions with Borrelia burgdorferi, the causative agent of Lyme disease, being the most common vector-borne pathogen in North America. Borrelia burgdorferi is a pathogen of high public health concern and there is significant variation in infection phenotype between strains, which influences predictions of pathogen dynamics and spread. In a laboratory experiment, we investigated whether two closely-related strains of B. burgdorferi (sensu stricto) showed similar transmission phenotypes, how the transmission of these strains changed when a host was infected with one strain, re-infected with the same strain, or co-infected with two strains. Ixodes scapularis, the black-legged tick, nymphs were used to sequentially infect laboratory-bred Peromyscus leucopus, white-footed mice, with one strain only, homologous infection with the same stain, or heterologous infection with both strains. We used the results of this laboratory experiment to simulate long-term persistence and maintenance of each strain in a simple simulation model. Strain LG734 was more competitive than BL206, showing no difference in transmission between the heterologous infection groups and single-infection controls, while strain BL206 transmission was significantly reduced when strain LG734 infected first. The results of the model show that this asymmetry in competition could lead to extinction of strain BL206 unless there was a tick-to-host transmission advantage to this less competitive strain. This asymmetric competitive interaction suggests that strain identity and

  2. Efficacy of the Non-Pathogenic Agrobacterium Strains K84 and K1026 against Crown Gall in Tunisia

    Directory of Open Access Journals (Sweden)

    A. Rhouma

    2004-08-01

    Full Text Available The non-pathogenic Agrobacterium radiobacter strain K84 and its genetically modified (GEM strain K1026 were tested for their effectiveness against local Tunisian strains and two reference strains (C58 and B6 of the crown gall bacterium Agrobacterium tumefaciens. Tests in planta were carried out on herbaceous plants (tomato and tagetes and on some sensitive rootstocks (bitter almond, peach almond hybrid GF677 and quince BA29. In vitro tests showed that both K84 and K1026 were effective and that the difference between these strains was not statistically significant. On tomato and tagetes, strain K84 was effective against all crown gall isolates with the exception of the A. tumefaciens reference strain B6. GEM strain K1026 was very effective against all isolates from Tunisia and against the reference strains. Both antagonistic strains significantly reduced the percentage of galled plants as well as the number of galls per plant. Under field conditions, both antagonists controlled crown gall effectively. Best results were obtained on the bitter almond-tree rootstock. Antagonist effectiveness was less evident on quince BA29 and peach almond GF677 rootstocks. The genetically modified strain K1026 is of interest in controlling crown gall disease in Tunisia.

  3. Draft Genome Sequences of the Fish Pathogen Vibrio harveyi Strains VH2 and VH5

    DEFF Research Database (Denmark)

    Castillo, Daniel; D'Alvise, Paul; Middelboe, Mathias

    2015-01-01

    Vibrio harveyi is an important marine pathogen that is responsible for vibriosis outbreaks in cultured fish and invertebrates worldwide. Here, we announce the draft genome sequences of V. harveyi strains VH2 and VH5, isolated from farmed juvenile Seriola dumerili during outbreaks of vibriosis...... in Crete, Greece....

  4. Use of Lactobacillus plantarum Strains as a Bio-Control Strategy against Food-Borne Pathogenic Microorganisms

    Science.gov (United States)

    Arena, Mattia Pia; Silvain, Amandine; Normanno, Giovanni; Grieco, Francesco; Drider, Djamel; Spano, Giuseppe; Fiocco, Daniela

    2016-01-01

    Lactobacillus plantarum is one of the most versatile species extensively used in the food industry both as microbial starters and probiotic microorganisms. Several L. plantarum strains have been shown to produce different antimicrobial compounds such as organic acids, hydrogen peroxide, diacetyl, and also bacteriocins and antimicrobial peptides, both denoted by a variable spectrum of action. In recent decades, the selection of microbial molecules and/or bacterial strains able to produce antagonistic molecules to be used as antimicrobials and preservatives has been attracting scientific interest, in order to eliminate or reduce chemical additives, because of the growing attention of consumers for healthy and natural food products. The aim of this work was to investigate the antimicrobial activity of several food-isolated L. plantarum strains, analyzed against the pathogenic bacteria Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli O157:H7 and Staphylococcus aureus. Antagonistic activity was assayed by agar spot test and revealed that strain L. plantarum 105 had the strongest ability to contrast the growth of L. monocytogenes, while strains L. plantarum 106 and 107 were the most active microorganisms against E. coli O157:H7. The antimicrobial ability was also screened by well diffusion assay and broth micro-dilution method using cell-free supernatants (CFS) from each Lactobacillus strain. Moreover, the chemical nature of the molecules released in the CFS, and possibly underlying the antagonistic activity, was preliminary characterized by exposure to different constraints such as pH neutralization, heating, catalase, and proteinase treatments. Our data suggest that the ability of L. plantarum cultures to contrast pathogens growth in vitro depends, at least in part, on a pH-lowering effect of supernatants and/or on the presence of organic acids. Cluster analysis was performed in order to group L. plantarum strains according to their antimicrobial effect

  5. Motor coordination and balance measurements reveal differential pathogenicity of currently spreading enterovirus 71 strains in human SCARB2 transgenic mice.

    Science.gov (United States)

    Chen, Mei-Feng; Shih, Shin-Ru

    2016-12-01

    Enterovirus 71 (EV71) has caused large-scale epidemics with neurological complications in the Asia-Pacific region. The C4a and B5 strains are the two major genotypes circulating in many countries recently. This study used a new protocol, a motor coordination task, to assess the differential pathogenicity of C4a and B5 strains in human SCARB2 transgenic mice. We found that the pathogenicity of C4a viruses was more severe than that of B5 viruses. Moreover, we discovered that an increased level of monocyte chemoattractant protein-1 was positively correlated with severely deficient motor function. This study provides a new method for evaluating EV71 infection in mice and distinguishing the severity of the symptoms caused by different clinical strains, which would contribute to studies of pathogenesis and development of vaccines and antivirals in EV71 infections.

  6. Multiple enzymatic profiles of Vibrio parahaemolyticus strains isolated from oysters

    Directory of Open Access Journals (Sweden)

    Renata Albuquerque Costa

    Full Text Available The enzymatic characterization of vibrios has been used as a virulence indicator of sanitary interest. The objective of this study was to determine the enzymatic profile of Vibrio parahaemolyticus strains (n = 70 isolated from Crassostrea rhizophorae oysters. The strains were examined for the presence of gelatinase (GEL, caseinase (CAS, elastase (ELAS, phospholipase (PHOS, lipase (LIP, amilase (AML and DNase. All enzymes, except elastase, were detected in more than 60% of the strains. The most recurrent enzymatic profiles were AML + DNase + PHOS + GEL + LIP (n = 16; 22.9% and AML + CAS + DNase + PHOS + GEL + LIP (n = 21; 30%. Considering the fact that exoenzyme production by vibrios is closely related to virulence, one must be aware of the bacteriological risk posed to human health by the consumption of raw or undercooked oysters.

  7. The complete genome sequence and comparative genome analysis of the high pathogenicity Yersinia enterocolitica strain 8081.

    Directory of Open Access Journals (Sweden)

    Nicholas R Thomson

    2006-12-01

    Full Text Available The human enteropathogen, Yersinia enterocolitica, is a significant link in the range of Yersinia pathologies extending from mild gastroenteritis to bubonic plague. Comparison at the genomic level is a key step in our understanding of the genetic basis for this pathogenicity spectrum. Here we report the genome of Y. enterocolitica strain 8081 (serotype 0:8; biotype 1B and extensive microarray data relating to the genetic diversity of the Y. enterocolitica species. Our analysis reveals that the genome of Y. enterocolitica strain 8081 is a patchwork of horizontally acquired genetic loci, including a plasticity zone of 199 kb containing an extraordinarily high density of virulence genes. Microarray analysis has provided insights into species-specific Y. enterocolitica gene functions and the intraspecies differences between the high, low, and nonpathogenic Y. enterocolitica biotypes. Through comparative genome sequence analysis we provide new information on the evolution of the Yersinia. We identify numerous loci that represent ancestral clusters of genes potentially important in enteric survival and pathogenesis, which have been lost or are in the process of being lost, in the other sequenced Yersinia lineages. Our analysis also highlights large metabolic operons in Y. enterocolitica that are absent in the related enteropathogen, Yersinia pseudotuberculosis, indicating major differences in niche and nutrients used within the mammalian gut. These include clusters directing, the production of hydrogenases, tetrathionate respiration, cobalamin synthesis, and propanediol utilisation. Along with ancestral gene clusters, the genome of Y. enterocolitica has revealed species-specific and enteropathogen-specific loci. This has provided important insights into the pathology of this bacterium and, more broadly, into the evolution of the genus. Moreover, wider investigations looking at the patterns of gene loss and gain in the Yersinia have highlighted common

  8. Pathogenic strains of Acanthamoeba are recognized by TLR4 and initiated inflammatory responses in the cornea.

    Directory of Open Access Journals (Sweden)

    Hassan Alizadeh

    Full Text Available Free-living amoebae of the Acanthamoeba species are the causative agent of Acanthamoeba keratitis (AK, a sight-threatening corneal infection that causes severe pain and a characteristic ring-shaped corneal infiltrate. Innate immune responses play an important role in resistance against AK. The aim of this study is to determine if Toll-like receptors (TLRs on corneal epithelial cells are activated by Acanthamoeba, leading to initiation of inflammatory responses in the cornea. Human corneal epithelial (HCE cells constitutively expressed TLR1, TLR2, TLR3, TLR4, and TLR9 mRNA, and A. castellanii upregulated TLR4 transcription. Expression of TLR1, TLR2, TLR3, and TLR9 was unchanged when HCE cells were exposed to A. castellanii. IL-8 mRNA expression was upregulated in HCE cells exposed to A. castellanii. A. castellanii and lipopolysaccharide (LPS induced significant IL-8 production by HCE cells as measured by ELISA. The percentage of total cells positive for TLR4 was higher in A. castellanii stimulated HCE cells compared to unstimulated HCE cells. A. castellanii induced upregulation of IL-8 in TLR4 expressing human embryonic kidney (HEK-293 cells, but not TLR3 expressing HEK-293 cells. TLR4 neutralizing antibody inhibited A. castellanii-induced IL-8 by HCE and HEK-293 cells. Clinical strains but not soil strains of Acanthamoeba activated TLR4 expression in Chinese hamster corneas in vivo and in vitro. Clinical isolates but not soil isolates of Acanthamoeba induced significant (P< 0.05 CXCL2 production in Chinese hamster corneas 3 and 7 days after infection, which coincided with increased inflammatory cells in the corneas. Results suggest that pathogenic species of Acanthamoeba activate TLR4 and induce production of CXCL2 in the Chinese hamster model of AK. TLR4 may be a potential target in the development of novel treatment strategies in Acanthamoeba and other microbial infections that activate TLR4 in corneal cells.

  9. The first pathogenic Yersinia enterocolitica bioserotype 4/O:3 strain isolated from a hunted wild boar (Sus scrofa) in Poland.

    Science.gov (United States)

    Bancerz-Kisiel, A; Platt-Samoraj, A; Szczerba-Turek, A; Syczyło, K; Szweda, W

    2015-10-01

    The objective of this study was to identify the bioserotypes and virulence markers of Yersinia enterocolitica strains isolated from wild boars in Poland. Bacteriological examination of 302 rectal swabs from 151 wild boars resulted in the isolation of 40 Y. enterocolitica strains. The majority of the examined strains (n = 30), belonged to bioserotype 1A/NI. The presence of individual Y. enterocolitica strains belonging to bioserotypes 1B/NI (3), 1A/O:8 (2), 1A/O:27 (2), 2/NI (1), 2/O:9 (1) and 4/O:3 (1) was also demonstrated. Amplicons corresponding to ail and ystA genes were observed only in one Y. enterocolitica strain--bioserotype 4/O:3. The ail and ystB gene amplicons were noted in 11 Y. enterocolitica biotype 1A strains, although single amplicons of ystB gene were found in 28 of the tested samples. In four out of eight cases when two Y. enterocolitica strains were isolated from the same animal, the strains differed in biotype, serotype or virulence markers. The European population of wild boars continues to grow and spread to new areas, therefore, wild boars harbouring potentially pathogenic Y. enterocolitica 4/O:3 strains pose a challenge to public health.

  10. Genomic and pathogenic analysis of a Muscovy duck parvovirus strain causing short beak and dwarfism syndrome without tongue protrusion.

    Science.gov (United States)

    Fu, Qiuling; Huang, Yu; Wan, Chunhe; Fu, Guanghua; Qi, Baomin; Cheng, Longfei; Shi, Shaohua; Chen, Hongmei; Liu, Rongchang; Chen, Zhenhai

    2017-12-01

    In 2008, clinical cases of short beak and dwarfism syndrome (SBDS) caused by Muscovy duck parvovirus (MDPV) infection were found in mule duck and Taiwan white duck farms in Fujian, China. A MDPV LH strain causing duck SBDS without tongue protrusion was isolated in this study. Phylogenetic analysis show that the MDPV LH strain was clustered together with other MDPV strains, but divergent from GPV isolates. Two major fragment deletions were found in the inverted terminal repeats (ITR) of MDPV LH similar to the ones in the ITR of MDPV GX5, YY and SAAS-SHNH strains. To investigate the pathogenicity of the MDPV LH strain, virus infection of young mule ducks was performed. The infected ducks showed SBDS symptoms including retard growth and shorten beaks without tongue protrusion. Atrophy of thymus, spleen and bursa of Fabricius was identified in the infected ducks. The results show that MDPV LH strain is moderately pathogenic to mule duck, leading to occurrence of SBDS. As far as we know, it is the first study showing that SBDS without tongue protrusion, and atrophy of thymus, spleen and bursa of Fabricius possibly associated with immunosuppression were found in the MDPV-infected ducks. The established duck-MDPV-SBDS system will help us to further work on the virus pathogenesis and develop efficacious vaccine against MDPV infection. Copyright © 2017. Published by Elsevier Ltd.

  11. NATURAL ATYPICAL LISTERIA INNOCUA STRAINS WITH LISTERIA MONOCYTOGENES PATHOGENICITY ISLAND 1 GENES

    Science.gov (United States)

    The detection of the human foodborne pathogen, Listeria monocytogenes, in food, environmental samples and clinical specimens associated with cases of listeriosis, a rare but high mortality-rate disease, requires distinguishing the pathogen from other Listeria species. Speciation...

  12. In vitro probiotic characterization of Lactobacillus strains from fermented radish and their anti-adherence activity against enteric pathogens.

    Science.gov (United States)

    Damodharan, Karthiyaini; Palaniyandi, Sasikumar Arunachalam; Yang, Seung Hwan; Suh, Joo-Won

    2015-11-01

    In this study, we evaluated the probiotic properties of Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus fermentum strains isolated from fermented radish. All the strains survived the simulated oro-gastrointestinal transit condition and showed significantly higher adherence to Caco-2 cells compared with the probiotic strain Lactobacillus rhamnosus GG. The strains showed broad-spectrum antimicrobial activity, autoaggregation, and coaggregation capacity with pathogens. Furthermore, the Lactobacillus strains inhibited the adherence of Yersinia enterocolitica subsp. enterocolitica, Shigella boydii, and Salmonella choleraesuis to the Caco-2 cell line. The strains possessed bile salt hydrolase activity and their cholesterol-lowering activity in vitro was above 50% in the presence of bile. Strains of L. plantarum and L. pentosus possessed the plantaricin-encoding plnEF gene. In addition, the Lactobacillus strains maintained about 80% cell viability after freeze-drying in the presence of a combination of 5% skim milk and 5% maltodextrin as cryoprotectant, and 70% recovery of cell viability was observed in the absence of any cryoprotectant.

  13. Multiple-Strain Approach and Probabilistic Modeling of Consumer Habits in Quantitative Microbial Risk Assessment: A Quantitative Assessment of Exposure to Staphylococcal Enterotoxin A in Raw Milk.

    Science.gov (United States)

    Crotta, Matteo; Rizzi, Rita; Varisco, Giorgio; Daminelli, Paolo; Cunico, Elena Cosciani; Luini, Mario; Graber, Hans Ulrich; Paterlini, Franco; Guitian, Javier

    2016-03-01

    Quantitative microbial risk assessment (QMRA) models are extensively applied to inform management of a broad range of food safety risks. Inevitably, QMRA modeling involves an element of simplification of the biological process of interest. Two features that are frequently simplified or disregarded are the pathogenicity of multiple strains of a single pathogen and consumer behavior at the household level. In this study, we developed a QMRA model with a multiple-strain approach and a consumer phase module (CPM) based on uncertainty distributions fitted from field data. We modeled exposure to staphylococcal enterotoxin A in raw milk in Lombardy; a specific enterotoxin production module was thus included. The model is adaptable and could be used to assess the risk related to other pathogens in raw milk as well as other staphylococcal enterotoxins. The multiplestrain approach, implemented as a multinomial process, allowed the inclusion of variability and uncertainty with regard to pathogenicity at the bacterial level. Data from 301 questionnaires submitted to raw milk consumers were used to obtain uncertainty distributions for the CPM. The distributions were modeled to be easily updatable with further data or evidence. The sources of uncertainty due to the multiple-strain approach and the CPM were identified, and their impact on the output was assessed by comparing specific scenarios to the baseline. When the distributions reflecting the uncertainty in consumer behavior were fixed to the 95th percentile, the risk of exposure increased up to 160 times. This reflects the importance of taking into consideration the diversity of consumers' habits at the household level and the impact that the lack of knowledge about variables in the CPM can have on the final QMRA estimates. The multiple-strain approach lends itself to use in other food matrices besides raw milk and allows the model to better capture the complexity of the real world and to be capable of geographical

  14. Customizable PCR-microplate array for differential identification of multiple pathogens.

    Science.gov (United States)

    Woubit, Abdela; Yehualaeshet, Teshome; Roberts, Sherrelle; Graham, Martha; Kim, Moonil; Samuel, Temesgen

    2013-11-01

    Customizable PCR-microplate arrays were developed for the rapid identification of Salmonella Typhimurium, Salmonella Saintpaul, Salmonella Typhi, Shigella dysenteriae, Escherichia coli O157:H7, Francisella tularensis subsp. tularensis, Francisella tularensis subsp. novicida, Vibrio cholerae, Vibrio parahaemolyticus, Yersinia pestis, and Yersinia pseudotuberculosis. Previously, we identified highly specific primers targeting each of these pathogens. Here, we report the development of customizable PCR-microplate arrays for simultaneous identification of the pathogens using the primers identified. A mixed aliquot of genomic DNA from 38 strains was used to validate three PCR-microplate array formats. Identical PCR conditions were used to run all the samples on the three formats. Specific amplifications were obtained on all three custom plates. In preliminary tests performed to evaluate the sensitivity of these assays in samples inoculated in the laboratory with Salmonella Typhimurium, amplifications were obtained from 1 g of beef hot dog inoculated at as low as 9 CFU/ml or from milk inoculated at as low as 78 CFU/ml. Such microplate arrays could be valuable tools for initial identification or secondary confirmation of contamination by these pathogens.

  15. In vitro evaluation of single- and multi-strain probiotics: Inter-species inhibition between probiotic strains, and inhibition of pathogens.

    Science.gov (United States)

    Chapman, C M C; Gibson, G R; Rowland, I

    2012-08-01

    Many studies comparing the effects of single- and multi-strain probiotics on pathogen inhibition compare treatments with different concentrations. They also do not examine the possibility of inhibition between probiotic strains with a mixture. We tested the ability of 14 single-species probiotics to inhibit each other using a cross-streak assay, and agar spot test. We then tested the ability of 15 single-species probiotics and 5 probiotic mixtures to inhibit Clostridium difficile, Escherichia coli and S. typhimurium, using the agar spot test. Testing was done with mixtures created in two ways: one group contained component species incubated together, the other group of mixtures was made using component species which had been incubated separately, equalised to equal optical density, and then mixed in equal volumes. Inhibition was observed for all combinations of probiotics, suggesting that when used as such there may be inhibition between probiotics, potentially reducing efficacy of the mixture. Significant inter-species variation was seen against each pathogen. When single species were tested against mixtures, the multi-species preparations displayed significantly (p probiotic species will inhibit each other when incubated together in vitro, in many cases a probiotic mixture was more effective at inhibiting pathogens than its component species when tested at approximately equal concentrations of biomass. This suggests that using a probiotic mixture might be more effective at reducing gastrointestinal infections, and that creating a mixture using species with different effects against different pathogens may have a broader spectrum of action that a single provided by a single strain. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Three New Pierce's Disease Pathogenicity Effectors Identified Using Xylella fastidiosa Biocontrol Strain EB92-1.

    Science.gov (United States)

    Zhang, Shujian; Chakrabarty, Pranjib K; Fleites, Laura A; Rayside, Patricia A; Hopkins, Donald L; Gabriel, Dean W

    2015-01-01

    Xylella fastidiosa (X. fastidiosa) infects a wide range of plant hosts and causes economically serious diseases, including Pierce's Disease (PD) of grapevines. X. fastidiosa biocontrol strain EB92-1 was isolated from elderberry and is infectious and persistent in grapevines but causes only very slight symptoms under ideal conditions. The draft genome of EB92-1 revealed that it appeared to be missing genes encoding 10 potential PD pathogenicity effectors found in Temecula1. Subsequent PCR and sequencing analyses confirmed that EB92-1 was missing the following predicted effectors found in Temecula1: two type II secreted enzymes, including a lipase (LipA; PD1703) and a serine protease (PD0956); two identical genes encoding proteins similar to Zonula occludens toxins (Zot; PD0915 and PD0928), and at least one relatively short, hemagglutinin-like protein (PD0986). Leaves of tobacco and citrus inoculated with cell-free, crude protein extracts of E. coli BL21(DE3) overexpressing PD1703 exhibited a hypersensitive response (HR) in less than 24 hours. When cloned into shuttle vector pBBR1MCS-5, PD1703 conferred strong secreted lipase activity to Xanthomonas citri, E. coli and X. fastidiosa EB92-1 in plate assays. EB92-1/PD1703 transformants also showed significantly increased disease symptoms on grapevines, characteristic of PD. Genes predicted to encode PD0928 (Zot) and a PD0986 (hemagglutinin) were also cloned into pBBR1MCS-5 and moved into EB92-1; both transformants also showed significantly increased symptoms on V. vinifera vines, characteristic of PD. Together, these results reveal that PD effectors include at least a lipase, two Zot-like toxins and a possibly redundant hemagglutinin, none of which are necessary for parasitic survival of X. fastidiosa populations in grapevines or elderberry.

  17. Three New Pierce's Disease Pathogenicity Effectors Identified Using Xylella fastidiosa Biocontrol Strain EB92-1.

    Directory of Open Access Journals (Sweden)

    Shujian Zhang

    Full Text Available Xylella fastidiosa (X. fastidiosa infects a wide range of plant hosts and causes economically serious diseases, including Pierce's Disease (PD of grapevines. X. fastidiosa biocontrol strain EB92-1 was isolated from elderberry and is infectious and persistent in grapevines but causes only very slight symptoms under ideal conditions. The draft genome of EB92-1 revealed that it appeared to be missing genes encoding 10 potential PD pathogenicity effectors found in Temecula1. Subsequent PCR and sequencing analyses confirmed that EB92-1 was missing the following predicted effectors found in Temecula1: two type II secreted enzymes, including a lipase (LipA; PD1703 and a serine protease (PD0956; two identical genes encoding proteins similar to Zonula occludens toxins (Zot; PD0915 and PD0928, and at least one relatively short, hemagglutinin-like protein (PD0986. Leaves of tobacco and citrus inoculated with cell-free, crude protein extracts of E. coli BL21(DE3 overexpressing PD1703 exhibited a hypersensitive response (HR in less than 24 hours. When cloned into shuttle vector pBBR1MCS-5, PD1703 conferred strong secreted lipase activity to Xanthomonas citri, E. coli and X. fastidiosa EB92-1 in plate assays. EB92-1/PD1703 transformants also showed significantly increased disease symptoms on grapevines, characteristic of PD. Genes predicted to encode PD0928 (Zot and a PD0986 (hemagglutinin were also cloned into pBBR1MCS-5 and moved into EB92-1; both transformants also showed significantly increased symptoms on V. vinifera vines, characteristic of PD. Together, these results reveal that PD effectors include at least a lipase, two Zot-like toxins and a possibly redundant hemagglutinin, none of which are necessary for parasitic survival of X. fastidiosa populations in grapevines or elderberry.

  18. New Genome Sequence of an Echinaceapurpurea Endophyte, Arthrobacter sp. Strain EpSL27, Able To Inhibit Human-Opportunistic Pathogens.

    Science.gov (United States)

    Miceli, Elisangela; Presta, Luana; Maggini, Valentina; Fondi, Marco; Bosi, Emanuele; Chiellini, Carolina; Fagorzi, Camilla; Bogani, Patrizia; Di Pilato, Vincenzo; Rossolini, Gian Maria; Mengoni, Alessio; Firenzuoli, Fabio; Perrin, Elena; Fani, Renato

    2017-06-22

    We announce here the draft genome sequence of Arthrobacter sp. strain EpSL27, isolated from the stem and leaves of the medicinal plant Echinacea purpurea and able to inhibit human-pathogenic bacterial strains. The genome sequencing of this strain may lead to the identification of genes involved in the production of antimicrobial molecules. Copyright © 2017 Miceli et al.

  19. Immune responses of mature chicken bone-marrow-derived dendritic cells infected with Newcastle disease virus strains with differing pathogenicity.

    Science.gov (United States)

    Xiang, Bin; Zhu, Wenxian; Li, Yaling; Gao, Pei; Liang, Jianpeng; Liu, Di; Ding, Chan; Liao, Ming; Kang, Yinfeng; Ren, Tao

    2018-06-01

    Infection of chickens with virulent Newcastle disease virus (NDV) is associated with severe pathology and increased morbidity and mortality. The innate immune response contributes to the pathogenicity of NDV. As professional antigen-presenting cells, dendritic cells (DCs) play a unique role in innate immunity. However, the contribution of DCs to NDV infection has not been investigated in chickens. In this study, we selected two representative NDV strains, i.e., the velogenic NDV strain Chicken/Guangdong/GM/2014 (GM) and the lentogenic NDV strain La Sota, to investigate whether NDVs could infect LPS-activated chicken bone-derived marrow DCs (mature chicken BM-DCs). We compared the viral titres and innate immune responses in mature chicken BM-DCs following infection with those strains. Both NDV strains could infect mature chicken BM-DC, but the GM strain showed stronger replication capacity than the La Sota strain in mature chicken BM-DCs. Gene expression profiling showed that MDA5, LGP2, TLR3, TLR7, IFN-α, IFN-β, IFN-γ, IL-1β, IL-6, IL-18, IL-8, CCL5, IL-10, IL-12, MHC-I, and MHC-II levels were altered in mature DCs after infection with NDVs at all evaluated times postinfection. Notably, the GM strain triggered stronger innate immune responses than the La Sota strain in chicken BM-DCs. However, both strains were able to suppress the expression of some cytokines, such as IL-6 and IFN-α, in mature chicken DCs at 24 hpi. These data provide a foundation for further investigation of the role of chicken DCs in NDV infection.

  20. Monoclonal IgG in MGUS and multiple myeloma targets infectious pathogens

    Science.gov (United States)

    Bosseboeuf, Adrien; Feron, Delphine; Tallet, Anne; Rossi, Cédric; Charlier, Cathy; Garderet, Laurent; Caillot, Denis; Moreau, Philippe; Cardó-Vila, Marina; Pasqualini, Renata; Nelson, Alfreda Destea; Wilson, Bridget S.; Perreault, Hélène; Piver, Eric; Weigel, Pierre; Harb, Jean; Bigot-Corbel, Edith; Hermouet, Sylvie

    2017-01-01

    Subsets of mature B cell neoplasms are linked to infection with intracellular pathogens such as Epstein-Barr virus (EBV), hepatitis C virus (HCV), or Helicobacter pylori. However, the association between infection and the immunoglobulin-secreting (Ig-secreting) B proliferative disorders remains largely unresolved. We investigated whether the monoclonal IgG (mc IgG) produced by patients diagnosed with monoclonal gammopathy of undetermined significance (MGUS) or multiple myeloma (MM) targets infectious pathogens. Antigen specificity of purified mc IgG from a large patient cohort (n = 244) was determined using a multiplex infectious-antigen array (MIAA), which screens for reactivity to purified antigens or lysates from 9 pathogens. Purified mc IgG from 23.4% of patients (57 of 244) specifically recognized 1 pathogen in the MIAA. EBV was the most frequent target (15.6%), with 36 of 38 mc IgGs recognizing EBV nuclear antigen-1 (EBNA-1). MM patients with EBNA-1–specific mc IgG (14.0%) showed substantially greater bone marrow plasma cell infiltration and higher β2-microglobulin and inflammation/infection–linked cytokine levels compared with other smoldering myeloma/MM patients. Five other pathogens were the targets of mc IgG: herpes virus simplex-1 (2.9%), varicella zoster virus (1.6%), cytomegalovirus (0.8%), hepatitis C virus (1.2%), and H. pylori (1.2%). We conclude that a dysregulated immune response to infection may underlie disease onset and/or progression of MGUS and MM for subsets of patients. PMID:28978808

  1. Priming by Rhizobacterium Protects Tomato Plants from Biotrophic and Necrotrophic Pathogen Infections through Multiple Defense Mechanisms

    Science.gov (United States)

    Ahn, Il-Pyung; Lee, Sang-Woo; Kim, Min Gab; Park, Sang-Ryeol; Hwang, Duk-Ju; Bae, Shin-Chul

    2011-01-01

    A selected strain of rhizobacterium, Pseudomonas putida strain LSW17S (LSW17S), protects tomato plants (Lycopersicon esculentum L. cv. Seokwang) from bacterial speck by biotrophic Pseudomonas syringae pv. tomato strain DC3000 (DC3000) and bacterial wilt by necrotrophic Ralstonia solanacearum KACC 10703 (Rs10703). To investigate defense mechanisms induced by LSW17S in tomato plants, transcription patterns of pathogenesis-related (PR) genes and H2O2 production were analyzed in plants treated with LSW17S and subsequent pathogen inoculation. LSW17S alone did not induce transcriptions of employed PR genes in leaves and roots. DC3000 challenge following LSW17S triggered rapid transcriptions of PR genes and H2O2 production in leaves and roots. Catalase infiltration with DC3000 attenuated defense-related responses and resistance against DC3000 infection. Despite depriving H2O2 production and PR1b transcription by the same treatment, resistance against Rs10703 infection was not deterred significantly. H2O2 is indispensable for defense signaling and/or mechanisms primed by LSW17S and inhibition of bacterial speck, however, it is not involved in resistance against bacterial wilt. PMID:21710203

  2. Development of multiple strain competitive index assays for Listeria monocytogenes using pIMC; a new site-specific integrative vector

    Directory of Open Access Journals (Sweden)

    Cronin Michael

    2008-06-01

    Full Text Available Abstract Background The foodborne, gram-positive pathogen, Listeria monocytogenes, is capable of causing lethal infections in compromised individuals. In the post genomic era of L. monocytogenes research, techniques are required to identify and validate genes involved in the pathogenicity and environmental biology of the organism. The aim here was to develop a widely applicable method to tag L. monocytogenes strains, with a particular emphasis on the development of multiple strain competitive index assays. Results We have constructed a new site-specific integrative vector, pIMC, based on pPL2, for the selection of L. monocytogenes from complex samples. The pIMC vector was further modified through the incorporation of IPTG inducible markers (antibiotic and phenotypic to produce a suite of four vectors which allowed the discrimination of multiple strains from a single sample. We were able to perform murine infection studies with up to four EGDe isolates within a single mouse and showed that the tags did not impact upon growth rate or virulence. The system also allowed the identification of subtle differences in virulence between strains of L. monocytogenes commonly used in laboratory studies. Conclusion This study has developed a competitive index assay that can be broadly applied to all L. monocytogenes strains. Improved statistical robustness of the data was observed, resulting in fewer mice being required for virulence assays. The competitive index assays provide a powerful method to analyse the virulence or fitness of L. monocytogenes in complex biological samples.

  3. Highly Pathogenic H5N1 Influenza A Virus Strains Provoke Heterogeneous IFN-α/β Responses That Distinctively Affect Viral Propagation in Human Cells

    Science.gov (United States)

    Matthaei, Markus; Budt, Matthias; Wolff, Thorsten

    2013-01-01

    The fatal transmissions of highly pathogenic avian influenza A viruses (IAV) of the H5N1 subtype to humans and high titer replication in the respiratory tract indicate that these pathogens can overcome the bird-to-human species barrier. While type I interferons (IFN-α/β) are well described to contribute to the species barrier of many zoonotic viruses, current data to the role of these antiviral cytokines during human H5N1 IAV infections is limited and contradictory. We hypothesized an important role for the IFN system in limiting productive infection of avian H5N1 strains in human cells. Hence, we examined IFN-α/β gene activation by different avian and human H5N1 isolates, if the IFN-α/β response restricts H5N1 growth and whether the different strains were equally capable to regulate the IFN-α/β system via their IFN-antagonistic NS1 proteins. Two human H5N1 isolates and a seasonal H3N2 strain propagated efficiently in human respiratory cells and induced little IFN-β, whereas three purely avian H5N1 strains were attenuated for replication and provoked higher IFN secretion. Replication of avian viruses was significantly enhanced on interferon-deficient cells, and exogenous IFN potently limited the growth of all strains in human cells. Moreover, IFN-α/β activation by all strains depended on retinoic acid-inducible gene I excluding principal differences in receptor activation between the different viruses. Interestingly, all H5N1 NS1 proteins suppressed IFN-α/β induction comparably well to the NS1 of seasonal IAV. Thus, our study shows that H5N1 strains are heterogeneous in their capacity to activate human cells in an NS1-independent manner. Our findings also suggest that H5N1 viruses need to acquire adaptive changes to circumvent strong IFN-α/β activation in human host cells. Since no single amino acid polymorphism could be associated with a respective high- or low induction phenotype we propose that the necessary adaptations to overcome the human IFN

  4. Highly pathogenic H5N1 influenza A virus strains provoke heterogeneous IFN-α/β responses that distinctively affect viral propagation in human cells.

    Directory of Open Access Journals (Sweden)

    Markus Matthaei

    Full Text Available The fatal transmissions of highly pathogenic avian influenza A viruses (IAV of the H5N1 subtype to humans and high titer replication in the respiratory tract indicate that these pathogens can overcome the bird-to-human species barrier. While type I interferons (IFN-α/β are well described to contribute to the species barrier of many zoonotic viruses, current data to the role of these antiviral cytokines during human H5N1 IAV infections is limited and contradictory. We hypothesized an important role for the IFN system in limiting productive infection of avian H5N1 strains in human cells. Hence, we examined IFN-α/β gene activation by different avian and human H5N1 isolates, if the IFN-α/β response restricts H5N1 growth and whether the different strains were equally capable to regulate the IFN-α/β system via their IFN-antagonistic NS1 proteins. Two human H5N1 isolates and a seasonal H3N2 strain propagated efficiently in human respiratory cells and induced little IFN-β, whereas three purely avian H5N1 strains were attenuated for replication and provoked higher IFN secretion. Replication of avian viruses was significantly enhanced on interferon-deficient cells, and exogenous IFN potently limited the growth of all strains in human cells. Moreover, IFN-α/β activation by all strains depended on retinoic acid-inducible gene I excluding principal differences in receptor activation between the different viruses. Interestingly, all H5N1 NS1 proteins suppressed IFN-α/β induction comparably well to the NS1 of seasonal IAV. Thus, our study shows that H5N1 strains are heterogeneous in their capacity to activate human cells in an NS1-independent manner. Our findings also suggest that H5N1 viruses need to acquire adaptive changes to circumvent strong IFN-α/β activation in human host cells. Since no single amino acid polymorphism could be associated with a respective high- or low induction phenotype we propose that the necessary adaptations to

  5. Comparative genomic characterization of three Streptococcus parauberis strains in fish pathogen, as assessed by wide-genome analyses.

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    Seong-Won Nho

    Full Text Available Streptococcus parauberis, which is the main causative agent of streptococcosis among olive flounder (Paralichthys olivaceus in northeast Asia, can be distinctly divided into two groups (type I and type II by an agglutination test. Here, the whole genome sequences of two Japanese strains (KRS-02083 and KRS-02109 were determined and compared with the previously determined genome of a Korean strain (KCTC 11537. The genomes of S. parauberis are intermediate in size and have lower GC contents than those of other streptococci. We annotated 2,236 and 2,048 genes in KRS-02083 and KRS-02109, respectively. Our results revealed that the three S. parauberis strains contain different genomic insertions and deletions. In particular, the genomes of Korean and Japanese strains encode different factors for sugar utilization; the former encodes the phosphotransferase system (PTS for sorbose, whereas the latter encodes proteins for lactose hydrolysis, respectively. And the KRS-02109 strain, specifically, was the type II strain found to be able to resist phage infection through the clustered regularly interspaced short palindromic repeats (CRISPR/Cas system and which might contribute valuably to serologically distribution. Thus, our genome-wide association study shows that polymorphisms can affect pathogen responses, providing insight into biological/biochemical pathways and phylogenetic diversity.

  6. The rhizosphere microbial community in a multiple parallel mineralization system suppresses the pathogenic fungus Fusarium oxysporum

    Science.gov (United States)

    Fujiwara, Kazuki; Iida, Yuichiro; Iwai, Takashi; Aoyama, Chihiro; Inukai, Ryuya; Ando, Akinori; Ogawa, Jun; Ohnishi, Jun; Terami, Fumihiro; Takano, Masao; Shinohara, Makoto

    2013-01-01

    The rhizosphere microbial community in a hydroponics system with multiple parallel mineralization (MPM) can potentially suppress root-borne diseases. This study focused on revealing the biological nature of the suppression against Fusarium wilt disease, which is caused by the fungus Fusarium oxysporum, and describing the factors that may influence the fungal pathogen in the MPM system. We demonstrated that the rhizosphere microbiota that developed in the MPM system could suppress Fusarium wilt disease under in vitro and greenhouse conditions. The microbiological characteristics of the MPM system were able to control the population dynamics of F. oxysporum, but did not eradicate the fungal pathogen. The roles of the microbiological agents underlying the disease suppression and the magnitude of the disease suppression in the MPM system appear to depend on the microbial density. F. oxysporum that survived in the MPM system formed chlamydospores when exposed to the rhizosphere microbiota. These results suggest that the microbiota suppresses proliferation of F. oxysporum by controlling the pathogen's morphogenesis and by developing an ecosystem that permits coexistence with F. oxysporum. PMID:24311557

  7. The rhizosphere microbial community in a multiple parallel mineralization system suppresses the pathogenic fungus Fusarium oxysporum.

    Science.gov (United States)

    Fujiwara, Kazuki; Iida, Yuichiro; Iwai, Takashi; Aoyama, Chihiro; Inukai, Ryuya; Ando, Akinori; Ogawa, Jun; Ohnishi, Jun; Terami, Fumihiro; Takano, Masao; Shinohara, Makoto

    2013-12-01

    The rhizosphere microbial community in a hydroponics system with multiple parallel mineralization (MPM) can potentially suppress root-borne diseases. This study focused on revealing the biological nature of the suppression against Fusarium wilt disease, which is caused by the fungus Fusarium oxysporum, and describing the factors that may influence the fungal pathogen in the MPM system. We demonstrated that the rhizosphere microbiota that developed in the MPM system could suppress Fusarium wilt disease under in vitro and greenhouse conditions. The microbiological characteristics of the MPM system were able to control the population dynamics of F. oxysporum, but did not eradicate the fungal pathogen. The roles of the microbiological agents underlying the disease suppression and the magnitude of the disease suppression in the MPM system appear to depend on the microbial density. F. oxysporum that survived in the MPM system formed chlamydospores when exposed to the rhizosphere microbiota. These results suggest that the microbiota suppresses proliferation of F. oxysporum by controlling the pathogen's morphogenesis and by developing an ecosystem that permits coexistence with F. oxysporum. © 2013 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  8. The potyviral suppressor of RNA silencing confers enhanced resistance to multiple pathogens

    International Nuclear Information System (INIS)

    Pruss, Gail J.; Lawrence, Christopher B.; Bass, Troy; Li Qingshun Q.; Bowman, Lewis H.; Vance, Vicki

    2004-01-01

    Helper component-protease (HC-Pro) is a plant viral suppressor of RNA silencing, and transgenic tobacco expressing HC-Pro has increased susceptibility to a broad range of viral pathogens. Here we report that these plants also exhibit enhanced resistance to unrelated heterologous pathogens. Tobacco mosaic virus (TMV) infection of HC-Pro-expressing plants carrying the N resistance gene results in fewer and smaller lesions compared to controls without HC-Pro. The resistance to TMV is compromised but not eliminated by expression of nahG, which prevents accumulation of salicylic acid (SA), an important defense signaling molecule. HC-Pro-expressing plants are also more resistant to tomato black ring nepovirus (TBRV) and to the oomycete Peronospora tabacina. Enhanced TBRV resistance is SA-independent, whereas the response to P. tabacina is associated with early induction of markers characteristic of SA-dependent defense. Thus, a plant viral suppressor of RNA silencing enhances resistance to multiple pathogens via both SA-dependent and SA-independent mechanisms

  9. The potyviral suppressor of RNA silencing confers enhanced resistance to multiple pathogens.

    Science.gov (United States)

    Pruss, Gail J; Lawrence, Christopher B; Bass, Troy; Li, Qingshun Q; Bowman, Lewis H; Vance, Vicki

    2004-03-01

    Helper component-protease (HC-Pro) is a plant viral suppressor of RNA silencing, and transgenic tobacco expressing HC-Pro has increased susceptibility to a broad range of viral pathogens. Here we report that these plants also exhibit enhanced resistance to unrelated heterologous pathogens. Tobacco mosaic virus (TMV) infection of HC-Pro-expressing plants carrying the N resistance gene results in fewer and smaller lesions compared to controls without HC-Pro. The resistance to TMV is compromised but not eliminated by expression of nahG, which prevents accumulation of salicylic acid (SA), an important defense signaling molecule. HC-Pro-expressing plants are also more resistant to tomato black ring nepovirus (TBRV) and to the oomycete Peronospora tabacina. Enhanced TBRV resistance is SA-independent, whereas the response to P. tabacina is associated with early induction of markers characteristic of SA-dependent defense. Thus, a plant viral suppressor of RNA silencing enhances resistance to multiple pathogens via both SA-dependent and SA-independent mechanisms.

  10. Replacement of glycoprotein B gene in the Herpes simplex virus type 1 strain ANGpath DNA that originating from non-pathogenic strain KOS reduces the pathogenicity of recombinant virus

    International Nuclear Information System (INIS)

    Kostal, M.; Bacik, I.; Rajcani, J.; Kaerner, H.C.

    1994-01-01

    Herpes simplex virus type-1 (HSV-1) strain ANGpath and its recombinants, in which the 8.1 kbp BamHI G restriction fragment (0.345-0.399) containing the glycoprotein B (gB path ) gene (UL27) or its sub-fragments-coding either for cytoplasmic or surface domain of gB-had been replaced with the corresponding fragments from non-pathogenic KOS virus DNA (gB KOS ), were tested for their pathogenicity for DBA/2 mice and rabbits. The recombinant ANGpath/B6 KOS prepared by transferring the 2.7 kbp SstI-SstI sub-fragment (0.351-0.368) of the BamHI G KOS fragment still had the original sequence of ANGpath DNA coding for the syn 3 marker in the cytoplasmic domain of gB and was pathogenic for mice as well as for rabbits. Virological and immuno-histological studies in DBA/2 mice infected with the latter pathogenic recombinant and with ANGpath showed the presence of infectious virus and viral antigen at inoculation site (epidermis, subcutaneous connective tissue and striated muscle in the area of right lip), in homo-lateral trigeminal nerve and ganglion, brain stem, midbrain, thalamic and hypothalamic nuclei. In contrast, non-pathogenic recombinants ANGpath/syn + B6 KOS (prepared by transferring the whole BamHI G KOS fragment) and ANGpath/syn +KOS (prepared by transferring the 0.8 kbp BamHI-SstI sub-fragment of the BamHI G KOS fragment) showed limited hematogenous and neural spread, but no evidence of replication in CNS; thus, their behaviour resembled that of the wild type strain KOS. The recombinant ANGpath/syn +KOS , which was not pathogenic for mice, still remained pathogenic for rabbits, a phenomenon indicating the presence of an additional locus in the gB molecule participating on virulence. Sequencing the 1478 bp SstI-SstI sub-fragment of the BamHI G path fragment (nt 53,348 - 54,826 of UL segment) showed the presence of at least 3 mutations as compared to the KOS sequence, from which the change of cytosine at nt 54,2251 altered the codon for arginine to that histidine

  11. Aptamer-based hydrogel barcodes for the capture and detection of multiple types of pathogenic bacteria.

    Science.gov (United States)

    Xu, Yueshuang; Wang, Huan; Luan, Chengxin; Liu, Yuxiao; Chen, Baoan; Zhao, Yuanjin

    2018-02-15

    Rapid and sensitive diagnosing hematological infections based on the separation and detection of pathogenic bacteria in the patient's blood is a significant challenge. To address this, we herein present a new barcodes technology that can simultaneously capture and detect multiple types of pathogenic bacteria from a complex sample. The barcodes are poly (ethylene glycol) (PEG) hydrogel inverse opal particles with characteristic reflection peak codes that remain stable during bacteria capture on their surfaces. As the spherical surface of the particles has ordered porous nanostructure, the barcodes can provide not only more surface area for probe immobilization and reaction, but also a nanopatterned platform for highly efficient bioreactions. In addition, the PEG hydrogel scaffold could decrease the non-specificity adsorption by its anti-adhesive effect, and the decorated aptamer probes in the scaffolds could increase the sensitivity, reliability, and specificity of the bacteria capture and detection. Moreover, the tagged magnetic nanoparticles in the PEG scaffold could impart the barcodes with controllable movement under magnetic fields, which can be used to significantly increase the reaction speed and simplify the processing of the bioassays. Based on the describe barcodes, it was demonstrated that the bacteria could be captured and identified even at low bacterial concentrations (100 CFU mL -1 ) within 2.5h, which is effectively shortened in comparison with the "gold standard" in clinic. These features make the barcodes ideal for capturing and detecting multiple bacteria from clinical samples for hematological infection diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Pathogenic Strains of Yersinia enterocolitica Isolated from Domestic Dogs (Canis familiaris) Belonging to Farmers Are of the Same Subtype as Pathogenic Y. enterocolitica Strains Isolated from Humans and May Be a Source of Human Infection in Jiangsu Province, China ▿ ‡

    Science.gov (United States)

    Wang, Xin; Cui, Zhigang; Wang, Hua; Tang, Liuying; Yang, Jinchuan; Gu, Ling; Jin, Dong; Luo, Longze; Qiu, Haiyan; Xiao, Yuchun; Xiong, Haiping; Kan, Biao; Xu, Jianguo; Jing, Huaiqi

    2010-01-01

    We isolated 326 Yersinia enterocolitica strains from 5,919 specimens from patients with diarrhea at outpatient clinics, livestock, poultry, wild animals, insect vectors, food, and the environment in the cities of Nantong and Xuzhou in Jiangsu Province, China, from 2004 to 2008. The results showed that the 12 pathogenic strains were of the O:3 serotype. Six strains were isolated from domestic dogs (Canis familiaris) belonging to farmers and were found to be the primary carriers of pathogenic Y. enterocolitica strains, especially in Xuzhou. Pulsed-field gel electrophoresis analysis of the pathogenic strains from dogs belonging to farmers showed that they shared the same patterns as strains from diarrhea patients isolated in 1994. This indicates that the strains from domestic dogs have a close correlation with the strains causing human infections. PMID:20181899

  13. Effects of bile salt deconjugation by probiotic strains on the survival of antibiotic-resistant foodborne pathogens under simulated gastric conditions.

    Science.gov (United States)

    He, Xinlong; Zou, Yunyun; Cho, Youngjae; Ahn, Juhee

    2012-06-01

    This study was designed to evaluate the effects of bile acid deconjugation by probiotic strains on the antibiotic susceptibility of antibiotic-sensitive and multiple antibiotic-resistant Salmonella Typhimurium and Staphylococcus aureus. Eight probiotic strains, Bifidobacterium longum B6, Lactobacillus acidophilus ADH, Lactobacillus brevis KACC 10553, Lactobacillus casei KACC 12413, Lactobacillus paracasei ATCC 25598, Lactobacillus rhamnosus GG, Leuconostoc mesenteroides KACC 12312, and Pediococcus acidilactici KACC 12307, were used to examine bile acid tolerance. The ability to deconjugate bile acids was evaluated using both thin-layer chromatography and high-performance liquid chromatography. The antibiotic susceptibility testing was carried out to determine the synergistic inhibitory activity of deconjugated bile acids. L. acidophilus, L. brevis, and P. acidilactici showed the most tolerance to the conjugated bile acids. P. acidilactici deconjugated glycocholic acid and glycodeoxycholate from 3.18 and 3.09 mM to the detection limits, respectively. The antibiotic susceptibility of selected foodborne pathogens was increased by increasing the concentration of deconjugated bile acids. The study results are useful for understanding the relationship between bile acid deconjugation by probiotic strains and antibiotic susceptibility in the presence of deconjugated bile acids, and they may be useful for designing new probiotic-antibiotic combination therapy based on bile acid deconjugation.

  14. Presence and Characterization of Extraintestinal Pathogenic Escherichia coli Virulence Genes in F165-Positive E. coli Strains Isolated from Diseased Calves and Pigs

    OpenAIRE

    Dezfulian, Hojabr; Batisson, Isabelle; Fairbrother, John M.; Lau, Peter C. K.; Nassar, Atef; Szatmari, George; Harel, Josée

    2003-01-01

    The virulence genotype profile and presence of a pathogenicity island(s) (PAI) were studied in 18 strains of F165-positive Escherichia coli originally isolated from diseased calves or piglets. On the basis of their adhesion phenotypes and genotypes, these extraintestinal pathogenic strains were classified into three groups. The F165 fimbrial complex consists of at least two serologically and genetically distinct fimbriae: F1651 and F1652. F1651 is encoded by the foo operon (pap-like), and F16...

  15. Prevalence of pathogens from Mollicutes class in cattle affected by respiratory diseases and molecular characteristics of Mycoplasma bovis field strains

    Directory of Open Access Journals (Sweden)

    Szacawa Ewelina

    2016-12-01

    Full Text Available Introduction: Mycoplasma bovis is one of the main pathogens involved in cattle pneumonia. Other mycoplasmas have also been directly implicated in respiratory diseases in cattle. The prevalence of different Mycoplasma spp. in cattle affected by respiratory diseases and molecular characteristics of M. bovis field strains were evaluated. Material and Methods: In total, 713 nasal swabs from 73 cattle herds were tested. The uvrC gene fragment was amplified by PCR and PCR products were sequenced. PCR/DGGE and RAPD were performed. Results: It was found that 39 (5.5% samples were positive for M. bovis in the PCR and six field strains had point nucleotide mutations. Additionally, the phylogenetic analysis of 20 M. bovis field strains tested with RAPD showed two distinct groups of M. bovis strains sharing only 3.8% similarity. PCR/DGGE analysis demonstrated the presence of bacteria belonging to the Mollicutes class in 79.1% of DNA isolates. The isolates were identified as: Mycoplasma bovirhinis, M. dispar, M. bovis, M. canis, M. arginini, M. canadense, M. bovoculi, M. alkalescens, and Ureaplasma diversum. Conclusion: Different Mycoplasma spp. strains play a crucial role in inducing respiratory diseases in cattle.

  16. The Genomic Sequence of the Oral Pathobiont Strain NI1060 Reveals Unique Strategies for Bacterial Competition and Pathogenicity.

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    Youssef Darzi

    Full Text Available Strain NI1060 is an oral bacterium responsible for periodontitis in a murine ligature-induced disease model. To better understand its pathogenicity, we have determined the complete sequence of its 2,553,982 bp genome. Although closely related to Pasteurella pneumotropica, a pneumonia-associated rodent commensal based on its 16S rRNA, the NI1060 genomic content suggests that they are different species thriving on different energy sources via alternative metabolic pathways. Genomic and phylogenetic analyses showed that strain NI1060 is distinct from the genera currently described in the family Pasteurellaceae, and is likely to represent a novel species. In addition, we found putative virulence genes involved in lipooligosaccharide synthesis, adhesins and bacteriotoxic proteins. These genes are potentially important for host adaption and for the induction of dysbiosis through bacterial competition and pathogenicity. Importantly, strain NI1060 strongly stimulates Nod1, an innate immune receptor, but is defective in two peptidoglycan recycling genes due to a frameshift mutation. The in-depth analysis of its genome thus provides critical insights for the development of NI1060 as a prime model system for infectious disease.

  17. Screening the Medicines for Malaria Venture Pathogen Box across Multiple Pathogens Reclassifies Starting Points for Open-Source Drug Discovery.

    Science.gov (United States)

    Duffy, Sandra; Sykes, Melissa L; Jones, Amy J; Shelper, Todd B; Simpson, Moana; Lang, Rebecca; Poulsen, Sally-Ann; Sleebs, Brad E; Avery, Vicky M

    2017-09-01

    Open-access drug discovery provides a substantial resource for diseases primarily affecting the poor and disadvantaged. The open-access Pathogen Box collection is comprised of compounds with demonstrated biological activity against specific pathogenic organisms. The supply of this resource by the Medicines for Malaria Venture has the potential to provide new chemical starting points for a number of tropical and neglected diseases, through repurposing of these compounds for use in drug discovery campaigns for these additional pathogens. We tested the Pathogen Box against kinetoplastid parasites and malaria life cycle stages in vitro Consequently, chemical starting points for malaria, human African trypanosomiasis, Chagas disease, and leishmaniasis drug discovery efforts have been identified. Inclusive of this in vitro biological evaluation, outcomes from extensive literature reviews and database searches are provided. This information encompasses commercial availability, literature reference citations, other aliases and ChEMBL number with associated biological activity, where available. The release of this new data for the Pathogen Box collection into the public domain will aid the open-source model of drug discovery. Importantly, this will provide novel chemical starting points for drug discovery and target identification in tropical disease research. Copyright © 2017 Duffy et al.

  18. Tomato immune receptor Ve1 recognizes effector of multiple fungal pathogens uncovered by genome and RNA sequencing

    NARCIS (Netherlands)

    Jonge, de R.; Esse, van H.P.; Maruthachalam, K.; Bolton, M.D.; Santhanam, P.; Keykha Saber, M.; Zhang, Z.; Usami, T.; Lievens, B.; Subbarao, K.V.; Thomma, B.

    2012-01-01

    Fungal plant pathogens secrete effector molecules to establish disease on their hosts, and plants in turn use immune receptors to try to intercept these effectors. The tomato immune receptor Ve1 governs resistance to race 1 strains of the soil-borne vascular wilt fungi Verticillium dahliae and

  19. Draft genome sequence of the fish pathogen Flavobacterium columnare strain CSF-298-10

    Science.gov (United States)

    We announce the genome assembly of Flavobacterium columnare strain CSF-298-10, a strain isolated from an outbreak of Columnaris disease at a commercial trout farm in Snake River Valley Idaho, USA. The complete genome consists of 13 contigs totaling 3,284,579 bp, average G+C content of 31.5% and 2933...

  20. Probiotic Escherichia coli strain Nissle 1917 outcompetes intestinal pathogens during biofilm formation

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Dahl, M.; Klemm, Per

    2010-01-01

    Nissle 1917 has been used for many decades as a probiotic against a variety of intestinal disorders and is probably the best field-tested E. coil strain in the world. Here we have investigated the biofilm-forming capacity of Nissle 1917. We found that the strain was a good biofilm former. Not only...

  1. In Vitro and In Vivo Characterization of a Typical and a High Pathogenic Bovine Viral Diarrhea Virus Type II Strains

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    Dario Amilcar Malacari

    2018-04-01

    Full Text Available Non-cytopathic (ncp type 2 bovine viral diarrhea virus (BVDV-2 is widely prevalent in Argentina causing high mortality rates in cattle herds. In this study, we characterized an Argentinean ncp BVDV-2 field isolate (98-124 compared to a high-virulence reference strain (NY-93, using in silico analysis, in vitro assays, and in vivo infections of colostrum-deprived calves (CDC to compare pathogenic characters and virulence. In vitro infection of bovine peripheral blood mononuclear cells (PBMC with BVDV 98-124 induced necrosis shortly after infection while NY-93 strain increased the apoptotic rate in infected cells. Experimental infection of CDC (n = 4 each with these strains caused an enteric syndrome. High pyrexia was detected in both groups. Viremia and shedding were more prolonged in the CDC infected with the NY-93 strain. In addition, NY-93 infection elicited a severe lymphopenia that lasted for 14 days, whereas 98-124 strain reduced the leukocyte counts for 5 days. All infected animals had a diminished lymphoproliferation activity in response to a mitogen. Neutralizing and anti-NS3 antibodies were detected 3 weeks after infection in all infected calves. Virulence was associated with a more severe clinical score, prolonged immune-suppression, and a greater window for transmission. Studies of apoptosis/necrosis performed after in vitro PBMC infection also revealed differences between both strains that might be correlated to the in vivo pathogenesis. Our results identified 98-124 as a low-virulence strain.

  2. Individual and co-operative roles of lactic acid and hydrogen peroxide in the killing activity of enteric strain Lactobacillus johnsonii NCC933 and vaginal strain Lactobacillus gasseri KS120.1 against enteric, uropathogenic and vaginosis-associated pathogens.

    Science.gov (United States)

    Atassi, Fabrice; Servin, Alain L

    2010-03-01

    The mechanism underlying the killing activity of Lactobacillus strains against bacterial pathogens appears to be multifactorial. Here, we investigate the respective contributions of hydrogen peroxide and lactic acid in killing bacterial pathogens associated with the human vagina, urinary tract or intestine by two hydrogen peroxide-producing strains. In co-culture, the human intestinal strain Lactobacillus johnsonii NCC933 and human vaginal strain Lactobacillus gasseri KS120.1 strains killed enteric Salmonella enterica serovar Typhimurium SL1344, vaginal Gardnerella vaginalis DSM 4944 and urinary tract Escherichia coli CFT073 pathogens. The cell-free culture supernatants (CFCSs) produced the same reduction in SL1344, DSM 4944 and CFT073 viability, whereas isolated bacteria had no effect. The killing activity of CFCSs was heat-stable. In the presence of Dulbecco's modified Eagle's minimum essential medium inhibiting the lactic acid-dependent killing activity, CFCSs were less effective at killing of the pathogens. Catalase-treated CFCSs displayed a strong decreased activity. Tested alone, hydrogen peroxide triggered a concentration-dependent killing activity against all three pathogens. Lactic acid alone developed a killing activity only at concentrations higher than that present in CFCSs. In the presence of lactic acid at a concentration present in Lactobacillus CFCSs, hydrogen peroxide displayed enhanced killing activity. Collectively, these results demonstrate that for hydrogen peroxide-producing Lactobacillus strains, the main metabolites of Lactobacillus, lactic acid and hydrogen peroxide, act co-operatively to kill enteric, vaginosis-associated and uropathogenic pathogens.

  3. Comparative genome analysis identifies two large deletions in the genome of highly-passaged attenuated Streptococcus agalactiae strain YM001 compared to the parental pathogenic strain HN016.

    Science.gov (United States)

    Wang, Rui; Li, Liping; Huang, Yan; Luo, Fuguang; Liang, Wanwen; Gan, Xi; Huang, Ting; Lei, Aiying; Chen, Ming; Chen, Lianfu

    2015-11-04

    Streptococcus agalactiae (S. agalactiae), also known as group B Streptococcus (GBS), is an important pathogen for neonatal pneumonia, meningitis, bovine mastitis, and fish meningoencephalitis. The global outbreaks of Streptococcus disease in tilapia cause huge economic losses and threaten human food hygiene safety as well. To investigate the mechanism of S. agalactiae pathogenesis in tilapia and develop attenuated S. agalactiae vaccine, this study sequenced and comparatively analyzed the whole genomes of virulent wild-type S. agalactiae strain HN016 and its highly-passaged attenuated strain YM001 derived from tilapia. We performed Illumina sequencing of DNA prepared from strain HN016 and YM001. Sequencedreads were assembled and nucleotide comparisons, single nucleotide polymorphism (SNP) , indels were analyzed between the draft genomes of HN016 and YM001. Clustered regularly interspaced short palindromic repeats (CRISPRs) and prophage were detected and analyzed in different S. agalactiae strains. The genome of S. agalactiae YM001 was 2,047,957 bp with a GC content of 35.61 %; it contained 2044 genes and 88 RNAs. Meanwhile, the genome of S. agalactiae HN016 was 2,064,722 bp with a GC content of 35.66 %; it had 2063 genes and 101 RNAs. Comparative genome analysis indicated that compared with HN016, YM001 genome had two significant large deletions, at the sizes of 5832 and 11,116 bp respectively, resulting in the deletion of three rRNA and ten tRNA genes, as well as the deletion and functional damage of ten genes related to metabolism, transport, growth, anti-stress, etc. Besides these two large deletions, other ten deletions and 28 single nucleotide variations (SNVs) were also identified, mainly affecting the metabolism- and growth-related genes. The genome of attenuated S. agalactiae YM001 showed significant variations, resulting in the deletion of 10 functional genes, compared to the parental pathogenic strain HN016. The deleted and mutated functional genes all

  4. Calibration of Multiple In Silico Tools for Predicting Pathogenicity of Mismatch Repair Gene Missense Substitutions

    Science.gov (United States)

    Thompson, Bryony A.; Greenblatt, Marc S.; Vallee, Maxime P.; Herkert, Johanna C.; Tessereau, Chloe; Young, Erin L.; Adzhubey, Ivan A.; Li, Biao; Bell, Russell; Feng, Bingjian; Mooney, Sean D.; Radivojac, Predrag; Sunyaev, Shamil R.; Frebourg, Thierry; Hofstra, Robert M.W.; Sijmons, Rolf H.; Boucher, Ken; Thomas, Alun; Goldgar, David E.; Spurdle, Amanda B.; Tavtigian, Sean V.

    2015-01-01

    Classification of rare missense substitutions observed during genetic testing for patient management is a considerable problem in clinical genetics. The Bayesian integrated evaluation of unclassified variants is a solution originally developed for BRCA1/2. Here, we take a step toward an analogous system for the mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) that confer colon cancer susceptibility in Lynch syndrome by calibrating in silico tools to estimate prior probabilities of pathogenicity for MMR gene missense substitutions. A qualitative five-class classification system was developed and applied to 143 MMR missense variants. This identified 74 missense substitutions suitable for calibration. These substitutions were scored using six different in silico tools (Align-Grantham Variation Grantham Deviation, multivariate analysis of protein polymorphisms [MAPP], Mut-Pred, PolyPhen-2.1, Sorting Intolerant From Tolerant, and Xvar), using curated MMR multiple sequence alignments where possible. The output from each tool was calibrated by regression against the classifications of the 74 missense substitutions; these calibrated outputs are interpretable as prior probabilities of pathogenicity. MAPP was the most accurate tool and MAPP + PolyPhen-2.1 provided the best-combined model (R2 = 0.62 and area under receiver operating characteristic = 0.93). The MAPP + PolyPhen-2.1 output is sufficiently predictive to feed as a continuous variable into the quantitative Bayesian integrated evaluation for clinical classification of MMR gene missense substitutions. PMID:22949387

  5. Comparative genome analysis of Prevotella intermedia strain isolated from infected root canal reveals features related to pathogenicity and adaptation.

    Science.gov (United States)

    Ruan, Yunfeng; Shen, Lu; Zou, Yan; Qi, Zhengnan; Yin, Jun; Jiang, Jie; Guo, Liang; He, Lin; Chen, Zijiang; Tang, Zisheng; Qin, Shengying

    2015-02-25

    Many species of the genus Prevotella are pathogens that cause oral diseases. Prevotella intermedia is known to cause various oral disorders e.g. periodontal disease, periapical periodontitis and noma as well as colonize in the respiratory tract and be associated with cystic fibrosis and chronic bronchitis. It is of clinical significance to identify the main drive of its various adaptation and pathogenicity. In order to explore the intra-species genetic differences among strains of Prevotella intermedia of different niches, we isolated a strain Prevotella intermedia ZT from the infected root canal of a Chinese patient with periapical periodontitis and gained a draft genome sequence. We annotated the genome and compared it with the genomes of other taxa in the genus Prevotella. The raw data set, consisting of approximately 65X-coverage reads, was trimmed and assembled into contigs from which 2165 ORFs were predicted. The comparison of the Prevotella intermedia ZT genome sequence with the published genome sequence of Prevotella intermedia 17 and Prevotella intermedia ATCC25611 revealed that ~14% of the genes were strain-specific. The Preveotella intermedia strains share a set of conserved genes contributing to its adaptation and pathogenic and possess strain-specific genes especially those involved in adhesion and secreting bacteriocin. The Prevotella intermedia ZT shares similar gene content with other taxa of genus Prevotella. The genomes of the genus Prevotella is highly dynamic with relative conserved parts: on average, about half of the genes in one Prevotella genome were not included in another genome of the different Prevotella species. The degree of conservation varied with different pathways: the ability of amino acid biosynthesis varied greatly with species but the pathway of cell wall components biosynthesis were nearly constant. Phylogenetic tree shows that the taxa from different niches are scarcely distributed among clades. Prevotella intermedia ZT

  6. Characterization of DegQVh, a serine protease and a protective immunogen from a pathogenic Vibrio harveyi strain.

    Science.gov (United States)

    Zhang, Wei-wei; Sun, Kun; Cheng, Shuang; Sun, Li

    2008-10-01

    Vibrio harveyi is an important marine pathogen that can infect a number of aquaculture species. V. harveyi degQ (degQ(Vh)), the gene encoding a DegQ homologue, was cloned from T4, a pathogenic V. harveyi strain isolated from diseased fish. DegQ(Vh) was closely related to the HtrA family members identified in other Vibrio species and could complement the temperature-sensitive phenotype of an Escherichia coli strain defective in degP. Expression of degQ(Vh) in T4 was modulated by temperature, possibly through the sigma(E)-like factor. Enzymatic analyses demonstrated that the recombinant DegQ(Vh) protein expressed in and purified from E. coli was an active serine protease whose activity required the integrity of the catalytic site and the PDZ domains. The optimal temperature and pH of the recombinant DegQ(Vh) protein were 50 degrees C and pH 8.0. A vaccination study indicated that the purified recombinant DegQ(Vh) was a protective immunogen that could confer protection upon fish against infection by V. harveyi. In order to improve the efficiency of DegQ(Vh) as a vaccine, a genetic construct in the form of the plasmid pAQ1 was built, in which the DNA encoding the processed DegQ(Vh) protein was fused with the DNA encoding the secretion region of AgaV, an extracellular beta-agarase. The E. coli strain harboring pAQ1 could express and secrete the chimeric DegQ(Vh) protein into the culture supernatant. Vaccination of fish with viable E. coli expressing chimeric degQ(Vh) significantly (P < 0.001) enhanced the survival of fish against V. harveyi challenge, which was possibly due to the relatively prolonged exposure of the immune system to the recombinant antigen produced constitutively, albeit at a gradually decreasing level, by the carrier strain.

  7. Cross-species infection of specific-pathogen-free pigs by a genotype 4 strain of human hepatitis E virus

    Science.gov (United States)

    Feagins, A. R.; Opriessnig, T.; Huang, Y. W.; Halbur, P. G.; Meng, X. J.

    2010-01-01

    SUMMARY Hepatitis E virus (HEV) is an important pathogen. The animal strain of HEV, swine HEV, is related to human HEV. The genotype 3 swine HEV infected humans and genotype 3 human HEV infected pigs. The genotype 4 swine and human HEV strains are genetically related, but it is unknown whether genotype 4 human HEV can infect pigs. A swine bioassay was utilized in this study to determine whether genotype 4 human HEV can infect pigs. Fifteen, 4-week-old, specific-pathogen-free pigs were divided into 3 groups of 5 each. Group 1 pigs were each inoculated intravenously with PBS buffer as negative controls, group 2 pigs similarly with genotype 3 human HEV (strain US-2), and group 3 pigs similarly with genotype 4 human HEV (strain TW6196E). Serum and fecal samples were collected at 0, 7, 14, 21, 28, 35, 42, 49, and 56 days postinoculation (dpi) and tested for evidence of HEV infection. All pigs were necropsied at 56 dpi. As expected, the negative control pigs remained negative. The positive control pigs inoculated with genotype 3 human HEV all became infected as evidenced by detection of HEV antibodies, viremia and fecal virus shedding. All five pigs in group 3 inoculated with genotype 4 human HEV also became infected: fecal virus shedding and viremia were detected variably from 7 to 56 dpi, and seroconversion occurred by 28 dpi. The data indicated that genotype 4 human HEV has an expanded host range, and the results have important implications for understanding the natural history and zoonosis of HEV. PMID:18551597

  8. Analysis of the genetic variation in Mycobacterium tuberculosis strains by multiple genome alignments

    Directory of Open Access Journals (Sweden)

    Morales Juan

    2008-11-01

    Full Text Available Abstract Background The recent determination of the complete nucleotide sequence of several Mycobacterium tuberculosis (MTB genomes allows the use of comparative genomics as a tool for dissecting the nature and consequence of genetic variability within this species. The multiple alignment of the genomes of clinical strains (CDC1551, F11, Haarlem and C, along with the genomes of laboratory strains (H37Rv and H37Ra, provides new insights on the mechanisms of adaptation of this bacterium to the human host. Findings The genetic variation found in six M. tuberculosis strains does not involve significant genomic rearrangements. Most of the variation results from deletion and transposition events preferentially associated with insertion sequences and genes of the PE/PPE family but not with genes implicated in virulence. Using a Perl-based software islandsanalyser, which creates a representation of the genetic variation in the genome, we identified differences in the patterns of distribution and frequency of the polymorphisms across the genome. The identification of genes displaying strain-specific polymorphisms and the extrapolation of the number of strain-specific polymorphisms to an unlimited number of genomes indicates that the different strains contain a limited number of unique polymorphisms. Conclusion The comparison of multiple genomes demonstrates that the M. tuberculosis genome is currently undergoing an active process of gene decay, analogous to the adaptation process of obligate bacterial symbionts. This observation opens new perspectives into the evolution and the understanding of the pathogenesis of this bacterium.

  9. Strain Dependent Genetic Networks for Antibiotic-Sensitivity in a Bacterial Pathogen with a Large Pan-Genome.

    Directory of Open Access Journals (Sweden)

    Tim van Opijnen

    2016-09-01

    Full Text Available The interaction between an antibiotic and bacterium is not merely restricted to the drug and its direct target, rather antibiotic induced stress seems to resonate through the bacterium, creating selective pressures that drive the emergence of adaptive mutations not only in the direct target, but in genes involved in many different fundamental processes as well. Surprisingly, it has been shown that adaptive mutations do not necessarily have the same effect in all species, indicating that the genetic background influences how phenotypes are manifested. However, to what extent the genetic background affects the manner in which a bacterium experiences antibiotic stress, and how this stress is processed is unclear. Here we employ the genome-wide tool Tn-Seq to construct daptomycin-sensitivity profiles for two strains of the bacterial pathogen Streptococcus pneumoniae. Remarkably, over half of the genes that are important for dealing with antibiotic-induced stress in one strain are dispensable in another. By confirming over 100 genotype-phenotype relationships, probing potassium-loss, employing genetic interaction mapping as well as temporal gene-expression experiments we reveal genome-wide conditionally important/essential genes, we discover roles for genes with unknown function, and uncover parts of the antibiotic's mode-of-action. Moreover, by mapping the underlying genomic network for two query genes we encounter little conservation in network connectivity between strains as well as profound differences in regulatory relationships. Our approach uniquely enables genome-wide fitness comparisons across strains, facilitating the discovery that antibiotic responses are complex events that can vary widely between strains, which suggests that in some cases the emergence of resistance could be strain specific and at least for species with a large pan-genome less predictable.

  10. The use of flagella and motility for plant colonization and fitness by different strains of the foodborne pathogen Listeria monocytogenes.

    Directory of Open Access Journals (Sweden)

    Lisa Gorski

    Full Text Available The role of flagella and motility in the attachment of the foodborne pathogen Listeria monocytogenes to various surfaces is mixed with some systems requiring flagella for an interaction and others needing only motility for cells to get to the surface. In nature this bacterium is a saprophyte and contaminated produce is an avenue for infection. Previous studies have documented the ability of this organism to attach to and colonize plant tissue. Motility mutants were generated in three wild type strains of L. monocytogenes by deleting either flaA, the gene encoding flagellin, or motAB, genes encoding part of the flagellar motor, and tested for both the ability to colonize sprouts and for the fitness of that colonization. The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability. The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion. A mutant in another background was only affected on alfalfa. The third, a poor alfalfa colonizer was not affected in colonization ability by any of the deletions. Fitness of colonization was measured in experiments of competition between mixtures of mutant and parent strains on sprouts. Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts. Together these data indicate a role for flagella for some strains to physically colonize some plants, while the fitness of that colonization is positively affected by motility in almost all cases.

  11. A strain of Serratia marcescens pathogenic for larvae of Lymantria dispar: Characterization

    Science.gov (United States)

    J.D. Podgwaite; B.J. Cosenza

    1976-01-01

    A gram-negative bacillus, pathogenic for gypsy moth larvae, was characterized culturally, morphologically, and physiologically as a member of the Serratia group of the family Enterobacteriaceae. The microorganism lacked the pigmentation characteristic of the group but was generally distinguished from closely related members of the family by its...

  12. Multi-Locus Next-Generation Sequence Typing of DNA Extracted From Pooled Colonies Detects Multiple Unrelated Candida albicans Strains in a Significant Proportion of Patient Samples

    Directory of Open Access Journals (Sweden)

    Ningxin Zhang

    2018-06-01

    Full Text Available The yeast Candida albicans is an important opportunistic human pathogen. For C. albicans strain typing or drug susceptibility testing, a single colony recovered from a patient sample is normally used. This is insufficient when multiple strains are present at the site sampled. How often this is the case is unclear. Previous studies, confined to oral, vaginal and vulvar samples, have yielded conflicting results and have assessed too small a number of colonies per sample to reliably detect the presence of multiple strains. We developed a next-generation sequencing (NGS modification of the highly discriminatory C. albicans MLST (multilocus sequence typing method, 100+1 NGS-MLST, for detection and typing of multiple strains in clinical samples. In 100+1 NGS-MLST, DNA is extracted from a pool of colonies from a patient sample and also from one of the colonies. MLST amplicons from both DNA preparations are analyzed by high-throughput sequencing. Using base call frequencies, our bespoke DALMATIONS software determines the MLST type of the single colony. If base call frequency differences between pool and single colony indicate the presence of an additional strain, the differences are used to computationally infer the second MLST type without the need for MLST of additional individual colonies. In mixes of previously typed pairs of strains, 100+1 NGS-MLST reliably detected a second strain. Inferred MLST types of second strains were always more similar to their real MLST types than to those of any of 59 other isolates (22 of 31 inferred types were identical to the real type. Using 100+1 NGS-MLST we found that 7/60 human samples, including three superficial candidiasis samples, contained two unrelated strains. In addition, at least one sample contained two highly similar variants of the same strain. The probability of samples containing unrelated strains appears to differ considerably between body sites. Our findings indicate the need for wider surveys to

  13. Pathogenic outcome following experimental infection of sheep with Chlamydia abortus variant strains LLG and POS.

    Science.gov (United States)

    Livingstone, Morag; Wheelhouse, Nicholas; Ensor, Hannah; Rocchi, Mara; Maley, Stephen; Aitchison, Kevin; Wattegedera, Sean; Wilson, Kim; Sait, Michelle; Siarkou, Victoria; Vretou, Evangelia; Entrican, Gary; Dagleish, Mark; Longbottom, David

    2017-01-01

    This study investigated the pathogenesis of two variant strains (LLG and POS) of Chlamydia abortus, in comparison to a typical wild-type strain (S26/3) which is known to be responsible for late term abortion in small ruminants. Challenge with the three strains at mid-gestation resulted in similar pregnancy outcomes, with abortion occurring in approximately 50-60% of ewes with the mean gestational lengths also being similar. However, differences were observed in the severity of placental pathology, with infection appearing milder for strain LLG, which was reflected in the lower number of organisms shed in vaginal swabs post-partum and less gross pathology and organisms present in placental smears. Results for strain POS were somewhat different than LLG with a more focal restriction of infection observed. Post-abortion antibody responses revealed prominent differences in seropositivity to the major outer membrane protein (MOMP) present in elementary body (EB) preparations under denaturing conditions, most notably with anti-LLG and anti-POS convalescent sera where there was no or reduced detection of MOMP present in EBs derived from the three strains. These results and additional analysis of whole EB and chlamydial outer membrane complex preparations suggest that there are conformational differences in MOMP for the three strains. Overall, the results suggest that gross placental pathology and clinical outcome is not indicative of bacterial colonization and the severity of infection. The results also highlight potential conformational differences in MOMP epitopes that perhaps impact on disease diagnosis and the development of new vaccines.

  14. Pathogenic outcome following experimental infection of sheep with Chlamydia abortus variant strains LLG and POS.

    Directory of Open Access Journals (Sweden)

    Morag Livingstone

    Full Text Available This study investigated the pathogenesis of two variant strains (LLG and POS of Chlamydia abortus, in comparison to a typical wild-type strain (S26/3 which is known to be responsible for late term abortion in small ruminants. Challenge with the three strains at mid-gestation resulted in similar pregnancy outcomes, with abortion occurring in approximately 50-60% of ewes with the mean gestational lengths also being similar. However, differences were observed in the severity of placental pathology, with infection appearing milder for strain LLG, which was reflected in the lower number of organisms shed in vaginal swabs post-partum and less gross pathology and organisms present in placental smears. Results for strain POS were somewhat different than LLG with a more focal restriction of infection observed. Post-abortion antibody responses revealed prominent differences in seropositivity to the major outer membrane protein (MOMP present in elementary body (EB preparations under denaturing conditions, most notably with anti-LLG and anti-POS convalescent sera where there was no or reduced detection of MOMP present in EBs derived from the three strains. These results and additional analysis of whole EB and chlamydial outer membrane complex preparations suggest that there are conformational differences in MOMP for the three strains. Overall, the results suggest that gross placental pathology and clinical outcome is not indicative of bacterial colonization and the severity of infection. The results also highlight potential conformational differences in MOMP epitopes that perhaps impact on disease diagnosis and the development of new vaccines.

  15. Pathogenicity and genetic variation of 3 strains of Corynebacterium bovis in immunodeficient mice.

    Science.gov (United States)

    Dole, Vandana S; Henderson, Kenneth S; Fister, Richard D; Pietrowski, Michael T; Maldonado, Geomaris; Clifford, Charles B

    2013-07-01

    Corynebacterium bovis has been associated with hyperkeratotic dermatitis and acanthosis in mice. We studied 3 different strains of C. bovis: one previously described to cause hyperkeratotic dermatitis (HAC), one that infected athymic nude mice without leading to the classic clinical signs, and one of bovine origin (ATCC 7715). The 3 strains showed a few biochemical and genetic differences. Immunodeficient nude mice were housed in 3 independent isolators and inoculated with pure cultures of the 3 strains. We studied the transmission of these C. bovis studies to isolator-bedding and contact sentinels housed for 5 to 12 wk in filter-top or wire-top cages in the respective isolators. Using a 16S rRNA-based qPCR assay, we did not find consistent differences in growth and transmission among the 3 C. bovis strains, and neither the incidence nor severity of hyperkeratosis or acanthosis differed between strains. Housing in filter-top compared with wire-top cages did not alter the morbidity associated with any of the strains. Our findings confirmed the variability in the gross and histologic changes associated with C. bovis infection of mice. Although bacteriology was a sensitive method for the detection of Corynebacterium spp., standard algorithms occasionally misidentified C. bovis and several related species. Our study demonstrates that PCR of skin swabs or feces is a sensitive and specific method for the detection of C. bovis infection in mice. An rpoB-based screen of samples from North American vivaria revealed that HAC is the predominant C. bovis strain in laboratory mice.

  16. Histopathological changes induced in an animal model by potentially pathogenic Enterococcus faecalis strains recovered from ready-to-eat food outlets in Osun State, Nigeria.

    Science.gov (United States)

    Olawale, Adetunji Kola; David, Oluwole Moses; Oluyege, Adekemi Olubukunola; Osuntoyinbo, Richard Temitope; Laleye, Solomon Anjuwon; Famurewa, Oladiran

    2015-01-01

    Enterococci have been implicated as an emerging important cause of several diseases and multiple antibiotic resistance. However, there is little information about the prevalence of pathogenic and/or antibiotic-resistant Enterococcus faecalis in ready-to-eat foods in Nigeria. Here we report the pathogenic potential of three selected antibiotic-resistant E. faecalis strains isolated from food canteens and food outlets with different virulence determinant genes, including EFC 12 (with gel (+), esp (+), cylA (+), and asa1 (+)), EFT 148 (with gel (+), ace (+), and asa1 (+)), and EFS 18 (with esp (+) and cylA (+)) in an animal model. Enterococcemia, hematological parameters, and histopathological changes in organ tissues were examined in experimental animals. The results showed differences in enterococcemia and hematological parameters between the control group and experimental animal group. Enterococcemia was observed for 7 days, and the animal group infected with EFC 12 showed the highest growth rate, followed by EFT 148, with the lowest growth rate seen in the EFS 18-infected group. White blood cell count, packed cell volume, and platelets were significantly reduced (Pfood canteens and food outlets; hence, there is a need for strict adherence to good hygiene practices in the study area owing to the epidemiological significance of foods.

  17. Histopathological changes induced in an animal model by potentially pathogenic Enterococcus faecalis strains recovered from ready-to-eat food outlets in Osun State, Nigeria

    Directory of Open Access Journals (Sweden)

    Olawale AK

    2015-06-01

    Full Text Available Adetunji Kola Olawale,1,2 Oluwole Moses David,2,3 Adekemi Olubukunola Oluyege,2 Richard Temitope Osuntoyinbo,4 Solomon Anjuwon Laleye,5 Oladiran Famurewa,21Department of Applied Sciences, Osun State Polytechnic, Iree, 2Department of Microbiology, University of Ado-Ekiti, Ado-Ekiti, Nigeria; 3Phytomedicine Research Centre, Department of Botany, University of Fort Hare, Alice, South Africa; 4Department of Microbiology, Waterford Regional Hospital, Waterford, Republic of Ireland; 5Department of Microbiology, Adekunle Ajasin University, Akungba-Akoko, NigeriaAbstract: Enterococci have been implicated as an emerging important cause of several diseases and multiple antibiotic resistance. However, there is little information about the prevalence of pathogenic and/or antibiotic-resistant Enterococcus faecalis in ready-to-eat foods in Nigeria. Here we report the pathogenic potential of three selected antibiotic-resistant E. faecalis strains isolated from food canteens and food outlets with different virulence determinant genes, including EFC 12 (with gel+, esp+, cylA+, and asa1+, EFT 148 (with gel+, ace+, and asa1+, and EFS 18 (with esp+ and cylA+ in an animal model. Enterococcemia, hematological parameters, and histopathological changes in organ tissues were examined in experimental animals. The results showed differences in enterococcemia and hematological parameters between the control group and experimental animal group. Enterococcemia was observed for 7 days, and the animal group infected with EFC 12 showed the highest growth rate, followed by EFT 148, with the lowest growth rate seen in the EFS 18-infected group. White blood cell count, packed cell volume, and platelets were significantly reduced (P<0.05 in the experimental animals compared with the controls. White blood cells decreased drastically during the study period in rats challenged with EFC 12 (from 7,800 to 6,120 per mm3 but levels remained higher in the control group (from 9,228 to 9

  18. Assessment of the pathogenicity of cell-culture-adapted Newcastle disease virus strain Komarov.

    Science.gov (United States)

    Visnuvinayagam, Sivam; Thangavel, K; Lalitha, N; Malmarugan, S; Sukumar, Kuppannan

    2015-01-01

    Newcastle disease vaccines hitherto in vogue are produced from embryonated chicken eggs. Egg-adapted mesogenic vaccines possess several drawbacks such as paralysis and mortality in 2-week-old chicks and reduced egg production in the egg-laying flock. Owing to these possible drawbacks, we attempted to reduce the vaccine virulence for safe vaccination by adapting the virus in a chicken embryo fibroblast cell culture (CEFCC) system. Eighteen passages were carried out by CEFCC, and the pathogenicity was assessed on the basis of the mean death time, intracerebral pathogenicity index, and intravenous pathogenicity index, at equal passage intervals. Although the reduction in virulence demonstrated with increasing passage levels in CEFCC was encouraging, 20% of the 2-week-old birds showed paralytic symptoms with the virus vaccine from the 18(th)(final) passage. Thus, a tissue-culture-adapted vaccine would demand a few more passages by CEFCC in order to achieve a complete reduction in virulence for use as a safe and effective vaccine, especially among younger chicks. Moreover, it can be safely administered even to unprimed 8-week-old birds.

  19. Molecular characterization and phylogenetic analysis of highly pathogenic Vibrio alginolyticus strains isolated during mortality outbreaks in cultured Ruditapes decussatus juvenile.

    Science.gov (United States)

    Mechri, Badreddine; Monastiri, Abir; Medhioub, Amel; Medhioub, Mohamed Nejib; Aouni, Mahjoub

    2017-10-01

    In the summer of 2008 and 2009, a series of mortalities in growing out seeds of R. decussatus juveniles were occurred in the eastern Tunisian littoral. Nine predominant bacterial strains were isolated from dead and moribund juveniles and characterized as Vibrio alginolyticus. These isolates were subjected to biochemical and molecular characterization. All the Vibrio strains were tested for their susceptibility against the most widely used antibiotic in aquaculture as well as, the assessment of the presence of erythromycin (emrB) and tetracycline (tetS) resistance genes among the tested bacteria. The degree of genetic relatedness between V. alginolyticus strains was evaluated on the basis of the Entero-Bacterial Repetitive Intergenic Consensus (ERIC) and the Random Amplification of Polymorphic DNA-PCR (RAPD-PCR) approaches. We also looked for siderophore activity and the ability to grow under iron limitation. Furthermore, the pathogenic potential of the tested isolates was evaluated using R. decussatus larva and juveniles as infection models. On antimicrobial susceptibility test, Vibrio strains exhibited total resistance to at least four antibiotics. The MICs data revealed that flumequine and oxolinic acid were the most effective antibiotics to control the studied bacteria. Results also showed that studied antibiotics resistance genes were widely disseminated in the genome of V. alginolyticus strains. Both ERIC and RAPD-PCR fingerprinting showed the presence of genetic variation among Vibrio isolates. However, RAPD typing exhibited a higher discriminative potential than ERIC-PCR. Besides, we reported here for the first time the co-production of catechol and hydroxamte by V. alginolyticus species. The challenge experiment showed that most of Vibrio isolates caused high mortality rates for both larva and juveniles at 48-h post-exposure to a bacterial concentration of 10 6  CFU/ml. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Plasmidome interchange between Clostridium botulinum, Clostridium novyi and Clostridium haemolyticum converts strains of independent lineages into distinctly different pathogens.

    Science.gov (United States)

    Skarin, Hanna; Segerman, Bo

    2014-01-01

    Clostridium botulinum (group III), Clostridium novyi and Clostridium haemolyticum are well-known pathogens causing animal botulism, gas gangrene/black disease, and bacillary hemoglobinuria, respectively. A close genetic relationship exists between the species, which has resulted in the collective term C. novyi sensu lato. The pathogenic traits in these species, e.g., the botulinum neurotoxin and the novyi alpha toxin, are mainly linked to a large plasmidome consisting of plasmids and circular prophages. The plasmidome of C. novyi sensu lato has so far been poorly characterized. In this study we explored the genomic relationship of a wide range of strains of C. novyi sensu lato with a special focus on the dynamics of the plasmidome. Twenty-four genomes were sequenced from strains selected to represent as much as possible the genetic diversity in C. novyi sensu lato. Sixty-one plasmids were identified in these genomes and 28 of them were completed. The genomic comparisons revealed four separate lineages, which did not strictly correlate with the species designations. The plasmids were categorized into 13 different plasmid groups on the basis of their similarity and conservation of plasmid replication or partitioning genes. The plasmid groups, lineages and species were to a large extent entwined because plasmids and toxin genes had moved across the lineage boundaries. This dynamic process appears to be primarily driven by phages. We here present a comprehensive characterization of the complex species group C. novyi sensu lato, explaining the intermixed genetic properties. This study also provides examples how the reorganization of the botulinum toxin and the novyi alpha toxin genes within the plasmidome has affected the pathogenesis of the strains.

  1. Plasmidome interchange between Clostridium botulinum, Clostridium novyi and Clostridium haemolyticum converts strains of independent lineages into distinctly different pathogens.

    Directory of Open Access Journals (Sweden)

    Hanna Skarin

    Full Text Available Clostridium botulinum (group III, Clostridium novyi and Clostridium haemolyticum are well-known pathogens causing animal botulism, gas gangrene/black disease, and bacillary hemoglobinuria, respectively. A close genetic relationship exists between the species, which has resulted in the collective term C. novyi sensu lato. The pathogenic traits in these species, e.g., the botulinum neurotoxin and the novyi alpha toxin, are mainly linked to a large plasmidome consisting of plasmids and circular prophages. The plasmidome of C. novyi sensu lato has so far been poorly characterized. In this study we explored the genomic relationship of a wide range of strains of C. novyi sensu lato with a special focus on the dynamics of the plasmidome. Twenty-four genomes were sequenced from strains selected to represent as much as possible the genetic diversity in C. novyi sensu lato. Sixty-one plasmids were identified in these genomes and 28 of them were completed. The genomic comparisons revealed four separate lineages, which did not strictly correlate with the species designations. The plasmids were categorized into 13 different plasmid groups on the basis of their similarity and conservation of plasmid replication or partitioning genes. The plasmid groups, lineages and species were to a large extent entwined because plasmids and toxin genes had moved across the lineage boundaries. This dynamic process appears to be primarily driven by phages. We here present a comprehensive characterization of the complex species group C. novyi sensu lato, explaining the intermixed genetic properties. This study also provides examples how the reorganization of the botulinum toxin and the novyi alpha toxin genes within the plasmidome has affected the pathogenesis of the strains.

  2. Characteristics of pathogenic Neisseria meningitidis in Moscow: prevalence of 'non-European' strains

    NARCIS (Netherlands)

    Koroleva, Irina S.; Platonov, Alexander E.; van der Ende, Arie; Kuijper, Ed; Dankert, Jacob

    1998-01-01

    OBJECTIVE: To investigate the distribution of serogroups, serotypes and subtypes, and susceptibility to antibiotics, of 75 strains isolated from patients with systemic meningococcal disease in Moscow in 1993--95. RESULTS: In contrast to the situation in most European countries, 21% of group A

  3. Risk of Human Infections With Highly Pathogenic H5N2 and Low Pathogenic H7N1 Avian Influenza Strains During Outbreaks in Ostriches in South Africa.

    Science.gov (United States)

    Venter, Marietjie; Treurnicht, Florette K; Buys, Amelia; Tempia, Stefano; Samudzi, Rudo; McAnerney, Johanna; Jacobs, Charlene A; Thomas, Juno; Blumberg, Lucille

    2017-09-15

    Risk factors for human infection with highly pathogenic (HP) and low-pathogenic (LP) avian influenza (AI) H5N2 and H7N1 were investigated during outbreaks in ostriches in the Western Cape province, South Africa. Serum surveys were conducted for veterinarians, farmworkers, and laboratory and abattoir workers involved in 2 AI outbreaks in the Western Cape province: (1) controlling and culling of 42000 ostriches during (HPAI)H5N2 outbreaks in ostriches (2011) (n = 207); (2) movement control during (LPAI)H7N1 outbreaks in 2012 (n = 66). A third serosurvey was conducted on state veterinarians from across the country in 2012 tasked with disease control in general (n = 37). Antibodies to H5 and H7 were measured by means of hemagglutination inhibition and microneutralization assays, with microneutralization assay titers >40 considered positive. Two of 207 (1%) participants were seropositive for H5 and 4 of 207 (2%) for H7 in 2011, compared with 1 of 66 (1.5%) and 8 of 66 (13%) in 2012. Although individuals in all professions tested seropositive, abattoir workers (10 of 97; 10.3%) were significantly more at risk of influenza A(H7N1) infection (P = .001) than those in other professions (2 of 171;1.2%). Among state veterinarians, 4 of 37(11%) were seropositive for H7 and 1 of 37 (2.7%) for H5. Investigations of (LP)H7N1-associated fatalities in wild birds and quarantined exotic birds in Gauteng, AI outbreaks in poultry in KwaZulu-Natal, and ostriches in Western Cape province provide possible exposure events. (LPAI)H7N1 strains pose a greater infection-risk than (HPAI)H5N2 strains to persons involved in control of outbreaks in infected birds, with ostrich abattoir workers at highest risk. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  4. Multiple candidate effectors from the oomycete pathogen Hyaloperonospora arabidopsidis suppress host plant immunity.

    Directory of Open Access Journals (Sweden)

    Georgina Fabro

    2011-11-01

    Full Text Available Oomycete pathogens cause diverse plant diseases. To successfully colonize their hosts, they deliver a suite of effector proteins that can attenuate plant defenses. In the oomycete downy mildews, effectors carry a signal peptide and an RxLR motif. Hyaloperonospora arabidopsidis (Hpa causes downy mildew on the model plant Arabidopsis thaliana (Arabidopsis. We investigated if candidate effectors predicted in the genome sequence of Hpa isolate Emoy2 (HaRxLs were able to manipulate host defenses in different Arabidopsis accessions. We developed a rapid and sensitive screening method to test HaRxLs by delivering them via the bacterial type-three secretion system (TTSS of Pseudomonas syringae pv tomato DC3000-LUX (Pst-LUX and assessing changes in Pst-LUX growth in planta on 12 Arabidopsis accessions. The majority (~70% of the 64 candidates tested positively contributed to Pst-LUX growth on more than one accession indicating that Hpa virulence likely involves multiple effectors with weak accession-specific effects. Further screening with a Pst mutant (ΔCEL showed that HaRxLs that allow enhanced Pst-LUX growth usually suppress callose deposition, a hallmark of pathogen-associated molecular pattern (PAMP-triggered immunity (PTI. We found that HaRxLs are rarely strong avirulence determinants. Although some decreased Pst-LUX growth in particular accessions, none activated macroscopic cell death. Fewer HaRxLs conferred enhanced Pst growth on turnip, a non-host for Hpa, while several reduced it, consistent with the idea that turnip's non-host resistance against Hpa could involve a combination of recognized HaRxLs and ineffective HaRxLs. We verified our results by constitutively expressing in Arabidopsis a sub-set of HaRxLs. Several transgenic lines showed increased susceptibility to Hpa and attenuation of Arabidopsis PTI responses, confirming the HaRxLs' role in Hpa virulence. This study shows TTSS screening system provides a useful tool to test whether

  5. MALDI-TOF-MS with PLS Modeling Enables Strain Typing of the Bacterial Plant Pathogen Xanthomonas axonopodis

    Science.gov (United States)

    Sindt, Nathan M.; Robison, Faith; Brick, Mark A.; Schwartz, Howard F.; Heuberger, Adam L.; Prenni, Jessica E.

    2018-02-01

    Matrix-assisted desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) is a fast and effective tool for microbial species identification. However, current approaches are limited to species-level identification even when genetic differences are known. Here, we present a novel workflow that applies the statistical method of partial least squares discriminant analysis (PLS-DA) to MALDI-TOF-MS protein fingerprint data of Xanthomonas axonopodis, an important bacterial plant pathogen of fruit and vegetable crops. Mass spectra of 32 X. axonopodis strains were used to create a mass spectral library and PLS-DA was employed to model the closely related strains. A robust workflow was designed to optimize the PLS-DA model by assessing the model performance over a range of signal-to-noise ratios (s/n) and mass filter (MF) thresholds. The optimized parameters were observed to be s/n = 3 and MF = 0.7. The model correctly classified 83% of spectra withheld from the model as a test set. A new decision rule was developed, termed the rolled-up Maximum Decision Rule (ruMDR), and this method improved identification rates to 92%. These results demonstrate that MALDI-TOF-MS protein fingerprints of bacterial isolates can be utilized to enable identification at the strain level. Furthermore, the open-source framework of this workflow allows for broad implementation across various instrument platforms as well as integration with alternative modeling and classification algorithms.

  6. Risk factors for fecal colonization with multiple distinct strains of Escherichia coli among long-term care facility residents.

    Science.gov (United States)

    Lautenbach, Ebbing; Tolomeo, Pam; Black, Nicole; Maslow, Joel N

    2009-05-01

    Of 49 long-term care facility residents, 21 (43%) were colonized with 2 or more distinct strains of Escherichia coli. There were no significant risk factors for colonization with multiple strains of E. coli. These results suggest that future efforts to efficiently identify the diversity of colonizing strains will be challenging.

  7. Establishment of a Pathogenicity Index for One-day-old Broilers to Pasteurella multocida Strains Isolated from Clinical Cases in Poultry and Swine

    Directory of Open Access Journals (Sweden)

    RM Pilatti

    Full Text Available ABSTRACT Although Pasteurella multocida is a member of the respiratory microbiota, under some circumstances, it is a primary agent of diseases , such as fowl cholera (FC, that cause significant economic losses. Experimental inoculations can be employed to evaluate the pathogenicity of strains, but the results are usually subjective and knowledge on the pathogenesis of this agent is still limited. The objective of this study was to establish a new methodology for classifying the pathogenicity of P. multocida by formulating a standard index. Strains isolated from FC cases and from swine with respiratory problems were selected. One hundred mL of a bacterial culture of each strain, containing 106 CFU, was inoculated in 10 one-day-old broilers. Mortality after inoculation, time of death (TD, and the presence of six macroscopic lesions were evaluated over a period of seven days post-inoculation (dpi. A Pathogenicity Index Per Bird (IPI, ranging 0 to 10, was calculated. Liver and heart fragments were collected to reisolate the bacteria. Blood was collected from the surviving birds, and an ELISA test was carried out to detect specific antibodies. The median of the pathogenicity indices, the number of lesions and the rate of bacteria reisolation were significantly different (p<0.05 among the origins of the isolates (p<0.05. The pathogenicity index developed in this study allows the classification of Pasteurella multocida pathogenicity and may be an alternative to the pathogenicity models currently used for screening.

  8. Draft Genome Sequences of Vibrio alginolyticus Strains V1 and V2, Opportunistic Marine Pathogens

    DEFF Research Database (Denmark)

    Castillo, Daniel; D'Alvise, Paul; Kalatzis, Panos G.

    2015-01-01

    We announce the draft genome sequences of Vibrio alginolyticus strains V1 and V2, isolated from juvenile Sparus aurata and Dentex dentex, respectively, during outbreaks of vibriosis. The genome sequences are 5,257,950 bp with a G+C content of 44.5% for V. alginolyticus V1 and 5,068,299 bp with a G...

  9. The potential pathogenicity of chlorhexidine-sensitive Acanthamoeba strains isolated from contact lens cases from asymptomatic individuals in Tenerife, Canary Islands, Spain.

    Science.gov (United States)

    Martín-Navarro, Carmen M; Lorenzo-Morales, Jacob; Cabrera-Serra, M Gabriela; Rancel, Fernando; Coronado-Alvarez, Nieves M; Piñero, José E; Valladares, Basilio

    2008-11-01

    Pathogenic strains of the genus Acanthamoeba are causative agents of a serious sight-threatening infection of the eye known as Acanthamoeba keratitis. The prevalence of this infection has risen in the past 20 years, mainly due to the increase in number of contact lens wearers. In this study, the prevalence of Acanthamoeba in a risk group constituted by asymptomatic contact lens wearers from Tenerife, Canary Islands, Spain, was evaluated. Contact lenses and contact lens cases were analysed for the presence of Acanthamoeba isolates. The isolates' genotypes were also determined after rDNA sequencing. The pathogenic potential of the isolated strains was subsequently established using previously described molecular and biochemical assays, which allowed the selection of three strains with high pathogenic potential. Furthermore, the sensitivity of these isolates against two standard drugs, ciprofloxacin and chlorhexidine, was analysed. As the three selected strains were sensitive to chlorhexidine, its activity and IC(50) were evaluated. Chlorhexidine was found to be active against these strains and the obtained IC(50) values were compared to the concentrations of this drug present in contact lens maintenance solutions. It was observed that the measured IC(50) was higher than the concentration found in these maintenance solutions. Therefore, the ineffectiveness of chlorhexidine-containing contact lens maintenance solutions against potentially pathogenic strains of Acanthamoeba is demonstrated in this study.

  10. Biological Efficacy of Streptomyces sp. Strain BN1 against the Cereal Head Blight Pathogen Fusarium graminearum

    Directory of Open Access Journals (Sweden)

    Boknam Jung

    2013-03-01

    Full Text Available Fusarium head blight (FHB caused by the filamentous fungus Fusarium graminearum is one of the most severe diseases threatening the production of small grains. Infected grains are often contaminated with mycotoxins such as zearalenone and trichothecences. During survey of contamination by FHB in rice grains, we found a bacterial isolate, designated as BN1, antagonistic to F. graminearum. The strain BN1 had branching vegetative hyphae and spores, and its aerial hyphae often had long, straight filaments bearing spores. The 16S rRNA gene of BN1 had 100% sequence identity with those found in several Streptomyces species. Phylogenetic analysis of ITS regions showed that BN1 grouped with S. sampsonii with 77% bootstrap value, suggesting that BN1 was not a known Streptomyces species. In addition, the efficacy of the BN1 strain against F. graminearum strains was tested both in vitro and in vivo. Wheat seedling length was significantly decreased by F. graminearum infection. However, this effect was mitigated when wheat seeds were treated with BN1 spore suspension prior to F. graminearum infection. BN1 also significantly decreased FHB severity when it was sprayed onto wheat heads, whereas BN1 was not effective when wheat heads were point inoculated. These results suggest that spraying of BN1 spores onto wheat heads during the wheat flowering season can be efficient for plant protection. Mechanistic studies on the antagonistic effect of BN1 against F. graminearum remain to be analyzed.

  11. Direct bacterial loop-mediated isothermal amplification detection on the pathogenic features of the nosocomial pathogen - Methicillin resistant Staphylococcus aureus strains with respiratory origins.

    Science.gov (United States)

    Lin, Qun; Xu, Pusheng; Li, Jiaowu; Chen, Yin; Feng, Jieyi

    2017-08-01

    Loop-mediated isothermal amplification based detection assays using bacterial culture or colony for direct detection of methicillin resistant Staphylococcus aureus(MRSA) had been developed and evaluated, followed by its extensive application on a large scale of clinical MRSA isolated from respiratory origins, including nasal swabs and sputums. Six primers, including outer primers, inner primers and loop primers, were specifically designed for recognizing eight distinct sequences on four targets: 16SrRNA, femA, mecA and orfX. Twenty-seven reference strains were used to develop, evaluate and optimize this assay. Then, a total of 532 clinical MRSA isolates were employed for each detected targets. And the results were determined through both visual observation of the color change by naked eye and electrophoresis. The specific of each primer had been confirmed, and the optimal amplification was obtained under 65 °C for 40 min. The limit of detections (LOD) of bacteria culture LAMP assays were determined to be 10 4  CFU/ml for 16S rRNA, femA, as well as orfX and 10 5  CFU/ml for mecA, respectively. The established novel assays on MRSA detection may provide new strategies for rapid detection of foodborne pathogens. Copyright © 2017. Published by Elsevier Ltd.

  12. Enhanced Control of Listeria monocytogenes by Enterococcus faecium KE82, a Multiple Enterocin-Producing Strain, in Different Milk Environments.

    Science.gov (United States)

    Vandera, Elpiniki; Lianou, Alexandra; Kakouri, Athanasia; Feng, Jinbo; Koukkou, Anna-Irini; Samelis, John

    2017-01-01

    Enterococcus faecium KE82, isolated from traditional Greek Graviera cheese, was identified in pure broth cultures in vitro as a multiple enterocin-producing bacterial strain possessing the structural entA, entB, and entP enterocin genes. E. faecium KE82 was further assessed for in situ antilisterial activity in raw milk (RM) and commercially thermized milk (TM; 63°C for 30 s) in the presence of the indigenous microbiota and in sterile raw milk (SRM; 121°C for 5 min) with or without the addition of two commercial starter culture (CSC) strains Streptococcus thermophilus and Lactococcus lactis . Growth of Listeria monocytogenes was completely inhibited in RM incubated at 37°C for 6 h, whereas the pathogen was significantly inactivated in RM+KE82 samples during further incubation at 18°C for 66 h. In contrast, L. monocytogenes levels increased by approximately 2 log CFU/ml in TM, but in TM+KE82 samples, pathogen growth was retarded during the first 6 h at 37°C followed by growth cessation and partial inactivation at 18°C. After 48 to 72 h, growth of L. monocytogenes in SRM+CSC samples decreased by 4 to 5 log CFU/ml compared with the SRM control, whereas additional 10-fold decreases in the pathogen were observed in SRM+CSC+KE82 samples. Reverse transcription PCR analysis of SRM+KE82 and SRM+CSC+KE82 samples confirmed that the entA and entB genes were transcribed, but entP gene transcription was not detected. All RM and SRM samples inoculated with E. faecium KE82 displayed strong in situ inhibitory activity against L. monocytogenes in well diffusion bioassays, whereas activity was weaker to undetectable in comparable or additional TM+KE82 samples; no milk sample without E. faecium KE82 had activity against L. monocytogenes . The findings of this study indicate that E. faecium KE82 is an antilisterial agent that could be used in traditional dairy foods because it concomitantly produces enterocins A and B in situ in milk.

  13. Prolonged excretion of a low-pathogenicity H5N2 avian influenza virus strain in the Pekin duck

    Science.gov (United States)

    Carranza-Flores, José Manuel; Padilla-Noriega, Luis; Loza-Rubio, Elizabeth

    2013-01-01

    H5N2 strains of low-pathogenicity avian influenza virus (LPAIV) have been circulating for at least 17 years in some Mexican chicken farms. We measured the rate and duration of viral excretion from Pekin ducks that were experimentally inoculated with an H5N2 LPAIV that causes death in embryonated chicken eggs (A/chicken/Mexico/2007). Leghorn chickens were used as susceptible host controls. The degree of viral excretion was evaluated with real-time reverse transcriptase-polymerase chain reaction (RRT-PCR) using samples from oropharyngeal and cloacal swabs. We observed prolonged excretion from both species of birds lasting for at least 21 days. Prolonged excretion of LPAIV A/chicken/Mexico/2007 is atypical. PMID:23820212

  14. Molecular characterization of canine parvovirus strains in Argentina: Detection of the pathogenic variant CPV2c in vaccinated dogs.

    Science.gov (United States)

    Calderon, Marina Gallo; Mattion, Nora; Bucafusco, Danilo; Fogel, Fernando; Remorini, Patricia; La Torre, Jose

    2009-08-01

    PCR amplification with sequence-specific primers was used to detect canine parvovirus (CPV) DNA in 38 rectal swabs from Argentine domestic dogs with symptoms compatible with parvovirus disease. Twenty-seven out of 38 samples analyzed were CPV positive. The classical CPV2 strain was not detected in any of the samples, but nine samples were identified as CPV2a variant and 18 samples as CPV2b variant. Further sequence analysis revealed a mutation at amino acid 426 of the VP2 gene (Asp426Glu), characteristic of the CPV2c variant, in 14 out of 18 of the samples identified initially by PCR as CPV2b. The appearance of CPV2c variant in Argentina might be dated at least to the year 2003. Three different pathogenic CPV variants circulating currently in the Argentine domestic dog population were identified, with CPV2c being the only variant affecting vaccinated and unvaccinated dogs during the year 2008.

  15. THE ROLE OF PIGS AS PHARYNGEAL CARRIERS OF HUMAN PATHOGENIC YERSINIA ENTEROCOLITICA STRAINS

    Directory of Open Access Journals (Sweden)

    M. D’Incau

    2013-02-01

    Full Text Available From March 2007 to January 2008, a total of 170 pigs at slaughter were tested for Y. enterocolitica contamination in tonsils tissue. The animals came from 125 different farms located in four regions of Northern Italy. Y. enterocolitica was isolated from 19 out of 170 (11.2% tonsils samples. The prevalent bio-serotype (68.4% was 4/O:3, followed by bioserotypes 1A/O:8 (15.8%, 1A/O:5 (10.5% and 4/O:8 (5.2%. Among bio-serotype 4/O:3, several strains possessed yadA, ail and ystA virulence genes.

  16. The Shewanella algae strain YM8 produces volatiles with strong inhibition activity against Aspergillus pathogens and aflatoxins

    Directory of Open Access Journals (Sweden)

    Andong eGong

    2015-10-01

    Full Text Available Aflatoxigenic Aspergillus fungi and associated aflatoxins are ubiquitous in the production and storage of food/feed commodities. Controlling these pests is a challenge. In this study, the Shewanella algae strain YM8 was found to produce volatiles that have strong antifungal activity against Aspergillus pathogens. Gas chromatography-mass spectrometry profiling revealed 15 volatile organic compounds (VOCs emitted from YM8, of which dimethyl trisulfide was the most abundant. We obtained authentic reference standards for six of the VOCs; these all significantly reduced mycelial growth and conidial germination in Aspergillus; dimethyl trisulfide and 2,4-bis(1,1-dimethylethyl-phenol showed the strongest inhibitory activity. YM8 completely inhibited Aspergillus growth and aflatoxin biosynthesis in maize and peanut samples stored at different water activity levels, and scanning electron microscopy revealed severely damaged conidia and a complete lack of mycelium development and conidiogenesis. YM8 also completely inhibited the growth of eight other agronomically important species of phytopathogenic fungi: A. parasiticus, A. niger, Alternaria alternate, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Monilinia fructicola, and Sclerotinia sclerotiorum. This study demonstrates the susceptibility of Aspergillus and other fungi to VOCs from marine bacteria and indicates a new strategy for effectively controlling these pathogens and the associated mycotoxin production in the field and during storage.

  17. Label-Free Quantitative Proteomic Analysis of Harmless and Pathogenic Strains of Infectious Microalgae, Prototheca spp.

    Directory of Open Access Journals (Sweden)

    Jayaseelan Murugaiyan

    2016-12-01

    Full Text Available Microalgae of the genus Prototheca (P. spp are associated with rare algal infections of invertebrates termed protothecosis. Among the seven generally accepted species, P. zopfii genotype 2 (GT2 is associated with a severe form of bovine mastitis while P. blaschkeae causes the mild and sub-clinical form of mastitis. The reason behind the infectious nature of P. zopfii GT2, while genotype 1 (GT1 remains non-infectious, is not known. Therefore, in the present study we investigated the protein expression level difference between the genotypes of P. zopfii and P. blaschkeae. Cells were cultured to the mid-exponential phase, harvested, and processed for LC-MS analysis. Peptide data was acquired on an LTQ Orbitrap Velos, raw spectra were quantitatively analyzed with MaxQuant software and matching with the reference database of Chlorella variabilis and Auxenochlorella protothecoides resulted in the identification of 226 proteins. Comparison of an environmental strain with infectious strains resulted in the identification of 51 differentially expressed proteins related to carbohydrate metabolism, energy production and protein translation. The expression level of Hsp70 proteins and their role in the infectious process is worth further investigation. All mass spectrometry data are available via ProteomeXchange with identifier PXD005305.

  18. Antibiosis of Trichoderma spp strains native to northeastern Mexico against the pathogenic fungus Macrophomina phaseolina

    Science.gov (United States)

    Mendoza, José Luis Hernández; Pérez, María Isabel Sánchez; Prieto, Juan Manuel González; Velásquez, Jesús DiCarlo Quiroz; Olivares, Jesús Gerardo García; Langarica, Homar Rene Gill

    2015-01-01

    Abstract Sampling of agricultural soils from the Mexican northeastern region was performed to detect Trichoderma spp., genetically characterize it, and assess its potential use as a biologic control agent against Macrophomina phaseolina. M. phaseolina is a phytopathogen that attacks over 500 species of cultivated plants and causes heavy losses in the regional sorghum crop. Sampling was performed immediately after sorghum or corn harvest in an area that was approximately 170 km from the Mexico-USA border. Sixteen isolates were obtained in total. Using colony morphology and sequencing the internal transcribed spacers (ITS) 1 and 4 of 18S rDNA, 14 strains were identified as Trichoderma harzianum, T. koningiopsis and T. virens. Subsequently, their antagonistic activity against M. phaseolina was evaluated in vitro, and 11 isolates showed antagonism by competition and stopped M. phaseolina growth. In 4 of these isolates, the antibiosis phenomenon was observed through the formation of an intermediate band without growth between colonies. One strain, HTE808, was identified as Trichoderma koningiopsis and grew rapidly; when it came into contact with the M. phaseolina colony, it continued to grow and sporulated until it covered the entire petri dish. Microscopic examination confirmed that it has a high level of hyperparasitism and is thus considered to have high potential for use in the control of this phytopathogen. PMID:26691467

  19. Helicobacter pylori strains from a Nigerian cohort show divergent antibiotic resistance rates and a uniform pathogenicity profile.

    Directory of Open Access Journals (Sweden)

    Ute Harrison

    Full Text Available Antibiotic resistance in Helicobacter pylori is a factor preventing its successful eradication. Particularly in developing countries, resistance against commonly used antibiotics is widespread. Here, we present an epidemiological study from Nigeria with 111 isolates. We analyzed the associated disease outcome, and performed a detailed characterization of these isolated strains with respect to their antibiotic susceptibility and their virulence characteristics. Furthermore, statistical analysis was performed on microbiological data as well as patient information and the results of the gastroenterological examination. We found that the variability concerning the production of virulence factors between strains was minimal, with 96.4% of isolates being CagA-positive and 92.8% producing detectable VacA levels. In addition, high frequency of bacterial resistance was observed for metronidazole (99.1%, followed by amoxicillin (33.3%, clarithromycin (14.4% and tetracycline (4.5%. In conclusion, this study indicated that the infection rate of H. pylori infection within the cohort in the present study was surprisingly low (36.6%. Furthermore, an average gastric pathology was observed by histological grading and bacterial isolates showed a uniform pathogenicity profile while indicating divergent antibiotic resistance rates.

  20. Pathogenicity of a strain of Yersinia pseudotuberculosis isolated from a pig with porcine colitis syndrome.

    Science.gov (United States)

    Neef, N A; Lysons, R J

    1994-07-16

    A strain of Yersinia pseudotuberculosis (NCTC 12718), isolated from a seven-week-old pig suffering from an ulcerative typhlocolitis, was inoculated orally into 16 growing pigs in two separate experiments. At necropsy 10 days later, typhlocolitis was present in nine of the pigs, and it was accompanied by diarrhoea in four cases. In both the original case and in the experimental pigs, the typhlocolitis was characterised by microabscesses of the lamina propria, frequently involving ulceration or erosion of the surface epithelium. The organism was of serotype IIa, which has not been isolated previously from pigs in the United Kingdom. Y pseudotuberculosis may be the aetiological agent responsible in some cases of porcine colitis syndrome.

  1. Increased pathogenicity and shedding in chickens of a wild bird-origin low pathogenicity avian influenza virus of the H7N3 subtype following multiple in vivo passages in quail and turkey.

    Science.gov (United States)

    Cilloni, Filippo; Toffan, Anna; Giannecchini, Simone; Clausi, Valeria; Azzi, Alberta; Capua, Ilaria; Terregino, Calogero

    2010-03-01

    In order to investigate viral adaptation mechanisms to poultry, we performed serial in vivo passages of a wild bird low pathogenicity avian influenza isolate of the H7N3 subtype (A/mallard/Italy/33/01) in three different domestic species (chicken, turkey, and Japanese quail). The virus under study was administered via natural routes at the dose of 10(6) egg infective dose50/ 0.1 ml to chickens, turkeys, and quails in order to investigate the clinical susceptibility and the shedding levels after infection. Multiple in vivo passages of the virus were performed by serially infecting groups of five naive birds of each species, with samples collected from a previously infected group. Quails and turkeys were susceptible to infection for 10 serial passages, whereas chickens were susceptible to two cycles of infection only. Infection of chicken with the quail- and turkey-adapted viruses showed an increased pathogenicity and/or shedding, causing more severe clinical signs and/or higher levels of viral excretion compared to the original strain. The data obtained herein suggest that infection of selected avian species may facilitate the adaptation of avian influenza viruses originating from the wild bird reservoir to chicken. This is the first time turkey has been shown to act as a species in which a virus from the wild reservoir can increase its replication activity in other domestic species.

  2. DNA microarray-based genome comparison of a pathogenic and a nonpathogenic strain of Xylella fastidiosa delineates genes important for bacterial virulence.

    Science.gov (United States)

    Koide, Tie; Zaini, Paulo A; Moreira, Leandro M; Vêncio, Ricardo Z N; Matsukuma, Adriana Y; Durham, Alan M; Teixeira, Diva C; El-Dorry, Hamza; Monteiro, Patrícia B; da Silva, Ana Claudia R; Verjovski-Almeida, Sergio; da Silva, Aline M; Gomes, Suely L

    2004-08-01

    Xylella fastidiosa is a phytopathogenic bacterium that causes serious diseases in a wide range of economically important crops. Despite extensive comparative analyses of genome sequences of Xylella pathogenic strains from different plant hosts, nonpathogenic strains have not been studied. In this report, we show that X. fastidiosa strain J1a12, associated with citrus variegated chlorosis (CVC), is nonpathogenic when injected into citrus and tobacco plants. Furthermore, a DNA microarray-based comparison of J1a12 with 9a5c, a CVC strain that is highly pathogenic and had its genome completely sequenced, revealed that 14 coding sequences of strain 9a5c are absent or highly divergent in strain J1a12. Among them, we found an arginase and a fimbrial adhesin precursor of type III pilus, which were confirmed to be absent in the nonpathogenic strain by PCR and DNA sequencing. The absence of arginase can be correlated to the inability of J1a12 to multiply in host plants. This enzyme has been recently shown to act as a bacterial survival mechanism by down-regulating host nitric oxide production. The lack of the adhesin precursor gene is in accordance with the less aggregated phenotype observed for J1a12 cells growing in vitro. Thus, the absence of both genes can be associated with the failure of the J1a12 strain to establish and spread in citrus and tobacco plants. These results provide the first detailed comparison between a nonpathogenic strain and a pathogenic strain of X. fastidiosa, constituting an important step towards understanding the molecular basis of the disease.

  3. Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms.

    Science.gov (United States)

    Mantilla-Calderon, David; Hong, Pei-Ying

    2017-07-01

    The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the

  4. Variation in the Early Host-Pathogen Interaction of Bovine Macrophages with Divergent Mycobacterium bovis Strains in the United Kingdom.

    Science.gov (United States)

    Jensen, Kirsty; Gallagher, Iain J; Johnston, Nicholas; Welsh, Michael; Skuce, Robin; Williams, John L; Glass, Elizabeth J

    2018-03-01

    Bovine tuberculosis has been an escalating animal health issue in the United Kingdom since the 1980s, even though control policies have been in place for over 60 years. The importance of the genetics of the etiological agent, Mycobacterium bovis , in the reemergence of the disease has been largely overlooked. We compared the interaction between bovine monocyte-derived macrophages (bMDM) and two M. bovis strains, AF2122/97 and G18, representing distinct genotypes currently circulating in the United Kingdom. These M. bovis strains exhibited differences in survival and growth in bMDM. Although uptake was similar, the number of viable intracellular AF2122/97 organisms increased rapidly, while G18 growth was constrained for the first 24 h. AF2122/97 infection induced a greater transcriptional response by bMDM than G18 infection with respect to the number of differentially expressed genes and the fold changes measured. AF2122/97 infection induced more bMDM cell death, with characteristics of necrosis and apoptosis, more inflammasome activation, and a greater type I interferon response than G18. In conclusion, the two investigated M. bovis strains interact in significantly different ways with the host macrophage. In contrast to the relatively silent infection by G18, AF2122/97 induces greater signaling to attract other immune cells and induces host cell death, which may promote secondary infections of naive macrophages. These differences may affect early events in the host-pathogen interaction, including granuloma development, which could in turn alter the progression of the disease. Therefore, the potential involvement of M. bovis genotypes in the reemergence of bovine tuberculosis in the United Kingdom warrants further investigation. Copyright © 2018 Jensen et al.

  5. Plant pathogens structure arthropod communities across multiple spatial and temporal scales

    NARCIS (Netherlands)

    Tack, A.J.M.; Dicke, M.

    2013-01-01

    Plant pathogens and herbivores frequently co-occur on the same host plants. Despite this, little is known about the impact of their interactions on the structure of plant-based ecological communities. Here, we synthesize evidence that indicates that plant pathogens may profoundly impact arthropod

  6. Potential Role of Diploscapter sp. Strain LKC25, a Bacterivorous Nematode from Soil, as a Vector of Food-Borne Pathogenic Bacteria to Preharvest Fruits and Vegetables

    Science.gov (United States)

    Gibbs, Daunte S.; Anderson, Gary L.; Beuchat, Larry R.; Carta, Lynn K.; Williams, Phillip L.

    2005-01-01

    Diploscapter, a thermotolerant, free-living soil bacterial-feeding nematode commonly found in compost, sewage, and agricultural soil in the United States, was studied to determine its potential role as a vehicle of Salmonella enterica serotype Poona, enterohemorrhagic Escherichia coli O157:H7, and Listeria monocytogenes in contaminating preharvest fruits and vegetables. The ability of Diploscapter sp. strain LKC25 to survive on agar media, in cow manure, and in composted turkey manure and to be attracted to, ingest, and disperse food-borne pathogens inoculated into soil or a mixture of soil and composted turkey manure was investigated. Diploscapter sp. strain LKC25 survived and reproduced in lawns of S. enterica serotype Poona, E. coli O157:H7, and L. monocytogenes on agar media and in cow manure and composted turkey manure. Attraction of Diploscapter sp. strain LKC25 to colonies of pathogenic bacteria on tryptic soy agar within 10, 20, 30, and 60 min and 24 h was determined. At least 85% of the worms initially placed 0.5 to 1 cm away from bacterial colonies migrated to the colonies within 1 h. Within 24 h, ≥90% of the worms were embedded in colonies. The potential of Diploscapter sp. strain LKC25 to shed pathogenic bacteria after exposure to bacteria inoculated into soil or a mixture of soil and composted turkey manure was investigated. Results indicate that Diploscapter sp. strain LKC25 can shed pathogenic bacteria after exposure to pathogens in these milieus. They also demonstrate its potential to serve as a vector of food-borne pathogenic bacteria in soil, with or without amendment with compost, to the surface of preharvest fruits and vegetables in contact with soil. PMID:15870330

  7. Draft genome sequence of pathogenic bacteria Vibrio parahaemolyticus strain Ba94C2, associated with acute hepatopancreatic necrosis disease isolate from South America

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    Leda Restrepo

    2016-09-01

    Full Text Available Vibrio parahaemolyticus is a pathogenic bacteria which has been associated to the early mortality syndrome (EMS also known as hepatopancreatic necrosis disease (AHPND causing high mortality in shrimp farms. Pathogenic strains contain two homologous genes related to insecticidal toxin genes, PirA and PirB, these toxin genes are located on a plasmid contained within the bacteria. Genomic sequences have allowed the finding of two strains with a divergent structure related to the geographic region from where they were found. The isolates from the geographic collection of Southeast Asia and Mexico show variable regions on the plasmid genome, indicating that even though they are not alike they still conserve the toxin genes. In this paper, we report for the first time, a pathogenic V. parahaemolyticus strain in shrimp from South America that showed symptoms of AHPND. The genomic analysis revealed that this strain of V. parahaemolyticus found in South America appears to be more related to the Southeast Asia as compared to the Mexican strains. This finding is of major importance for the shrimp industry, especially in regards to the urgent need for disease control strategies to avoid large EMS outbreaks and economic loss, and to determine its dispersion in South America. The whole-genome shotgun project of V. parahaemolyticus strain Ba94C2 have been deposited at DDBJ/EMBL/GenBank under the accession PRJNA335761.

  8. Antifungal activity of Andrographis paniculata extracts and active principles against skin pathogenic fungal strains in vitro.

    Science.gov (United States)

    Sule, Abubakar; Ahmed, Qamar Uddin; Latip, Jalifah; Samah, Othman Abd; Omar, Muhammad Nor; Umar, Abdulrashid; Dogarai, Bashar Bello S

    2012-07-01

    Andrographis paniculata Nees. (Acanthaceae) is an annual herbaceous plant widely cultivated in southern Asia, China, and Europe. It is used in the treatment of skin infections in India, China, and Malaysia by folk medicine practitioners. Antifungal activity of the whole plant extracts and isolation of active principles from A. paniculata were investigated. Dichloromethane (DCM) and methanol (MEOH) extracts of A. paniculata whole plant were screened for their antifungal potential using broth microdilution method in vitro against seven pathogenic fungal species responsible for skin infections. Active principles were detected through bioguided assays and isolated using chromatography techniques. Structures of compounds were elucidated through spectroscopy techniques and comparisons were made with previously reported data for similar compounds. DCM extract revealed lowest minimum inhibitory concentration (MIC) value (100 μg/mL) against Microsporum canis, Candida albicans, and Candida tropicalis, whereas MEOH extract revealed lowest MIC (150 µg/mL) against C. tropicalis and Aspergillus niger. DCM extract showed lowest minimum fungicidal concentration (MFC) value (250 µg/mL) against M. canis, C. albicans, C. tropicalis and A. niger, whereas MEOH extract showed lowest MFC (250 µg/mL) against Trichophyton mentagrophytes, Trichophyton rubrum, M. canis, C. albicans, C. tropicalis and A. niger. Bioassay guided isolation from DCM and MEOH extract afforded 3-O-β-d-glucosyl-14-deoxyandrographiside, 14-deoxyandrographolide, and 14-deoxy-11,12-didehydroandrographolide as antifungal compounds. The lowest MIC (50 µg/mL) and MFC (50 µg/mL) was exerted by 14-deoxyandrographolide on M. canis. This is first report on the isolation of antifungal substances through bioassay-guided assay from A. paniculata. Our finding justifies the use of A. paniculata in folk medicines for the treatment of fungal skin infections.

  9. Antibacterial activity of combined medicinal plants extract against multiple drug resistant strains

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    Rafiqul Islam

    2015-06-01

    Full Text Available Objective: To find out the combined antibacterial efficacy of Aegle marmelos, Aphanamixis polystachya, Cuscuta reflexa and Aesclynomene indica against bacterial pathogens. Methods: Antibacterial potency of combined plant extracts has been tested against Bacillus subtilis IFO 3026, Sarcina lutea IFO 3232, Xanthomonas campestris IAM 1671, Escherichia coli IFO 3007, Klebsiella pneumoniae ATTC 10031, Proteus vulgaris MTCC 321 and Pseudomonas denitrificans KACC 32026 by disc diffusion assay. Commercially available standard antibiotic discs were also used to find out antibiotic resistance pattern of test organisms. Results: Among the test organisms, Escherichia coli, Proteus vulgaris, Klebsiella pneumoniae and Proteus denitrificans showed resistance against multiple commercially available antibiotics. On the other hand, these multiple drug resistant organisms showed susceptibility against combined plant extracts. Conclusions: These combined plants extracts showed synergistic antibacterial activity and could lead to new antibacterial drug designing.

  10. ISOLATION OF THE GENOME SEQUENCE STRAIN MYCOBACTERIUM AVIUM 104 FROM MULTIPLE PATIENTS OVER A 17-YEAR PERIOD

    Science.gov (United States)

    The genome sequence strain 104 of the opportunistic pathogen Mycobacterium avium was isolated form an adult AIDS patient in Southern California in 1983. Isolates of non-paratuberculosis M. avium from 207 other patients in Southern California and elsewhere were examined for genoty...

  11. ANTIMICROBIAL ACTIVITY OF ETHANOL EXTRACT OF SATUREJA HORTENSIS L. TOWARDS PATHOGENIC MICROBIAL STRAINS

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    Kotyuk L. A.

    2014-12-01

    Full Text Available The paper provides the information on the component composition of ethereal oil of Satureja hortensis cultivated in Zhytomyr Polissya. In the ethereal oil of summer savory, 19 components were identified: carvacrol (89,07%, γ-terpinene (3,53%, α-thujone (1,7%, camphora (1,48%, terpinen-4 ol 4 (0,91%, β-bisabolen (0,56%, β-caryophyllene (0,45%, bitsiklogermakren (0,38% para-cymene (0,34%, 1,8-cineole (0,33%, trans-sabinengidrat (0.25%, 1-octen-3-ol (0.20%, spatulenol (0,18%, β-thujone (0,14%, eugenol (0,11%, geranylacetate (0,11%, humulene (0,09%, α-terpinene (0,09%, octanol-3 (0,07%. A high carvacrol content determines antimicrobial properties of summer savory. The antimicrobial activity of S. hortensis extract was studied in accordance with the common methodology of determining the sensitivity of microorganisms to antibacterial preparations. The aboveground part of plants harvested in the last ten-day period of August, in the flowering phase, was used in the experiments. The raw material was reduced to fragments of 1-1.5mm according to the requirements of pharmacopoeia. The extract of S. hortensis was obtained by the method of maceration in 40% ethyl alcohol at a ratio of 1:5 and the concentration of 200mg/ml. The availability of antimicrobial activity of extracted substances in the structure of the substances studied was determined by the way of comparison of their minimum inhibiting concentrations (MIC and minimum bactericidal/fungicidal concentrations (MBC/MFC with those in 40% ethyl alcohol. The paper investigates the biological activity of 40 % ethanol extract of Satureja hortensis herb grown under the conditions of Ukrainian Polissya as to golden staphylococcus (Staphylococcus aureus, coliform bacillus Escherichia coli, Pseudomonas aeruginosa and Candida albicans which are pathogenic in reference to other organisms. It has been shown that S. hortensis extract was characterized by antimicrobial activity since extracted substances

  12. Draft Genome Sequence of Rhizobium sp. Strain TBD182, an Antagonist of the Plant-Pathogenic Fungus Fusarium oxysporum, Isolated from a Novel Hydroponics System Using Organic Fertilizer.

    Science.gov (United States)

    Iida, Yuichiro; Fujiwara, Kazuki; Someya, Nobutaka; Shinohara, Makoto

    2017-03-16

    Rhizobium sp. strain TBD182, isolated from a novel hydroponics system, is an antagonistic bacterium that inhibits the mycelial growth of Fusarium oxysporum but does not eliminate the pathogen. We report the draft genome sequence of TBD182, which may contribute to elucidation of the molecular mechanisms of its fungistatic activity. Copyright © 2017 Iida et al.

  13. [Phenotypic and genotypic identification of Candida strains isolated as nosocomial pathogens].

    Science.gov (United States)

    Sahiner, Fatih; Ergünay, Koray; Ozyurt, Mustafa; Ardıç, Nurittin; Hoşbul, Tuğrul; Haznedaroğlu, Tunçer

    2011-07-01

    Over the last decade, there have been important changes in the epidemiology of Candida infections and antifungal agents used to treat these infections. In recent years, Candida species have emerged as important causes of invasive infections among patients in intensive care units. One of the main goals of this study was to evaluate the molecular epidemiology of infectious Candida species isolated in our hospital and accordingly supply data for hospital infection (HI) control. The other aim of this study was to evaluate effectiveness and practical applicability of traditional and molecular methods used to identify Candida isolates to the species level. A total of 77 Candida strains that were isolated from various clinical specimens of 60 hospitalized patients (29 male, 24 female; 7 were children) were included in the study. Fifty-seven (74%) of those isolates were defined as HI agents according to Centers for Disease Control and Prevention (CDC) criteria. The most common Candida species identified as agents of HI were C.albicans (22; 38.6%), followed by C.tropicalis (14; 24.6%), C.parapsilosis (13; 22.8%), C.glabrata (7; 12.3%) and Candida spp. (1; 1.75%). It was determined that bloodstream (26; 45.6%) and urinary tract infections (24; 42.1%) were the most frequently encountered nosocomial infections caused by Candida species. In addition it was detected that the most frequent causative agent of bloodstream infections was C.parapsilosis (10; 38.5%) and of urinary tract infections was C.albicans (12; 50%). The evaluation of advantages and disadvantages of traditional phenotypic methods [germ tube formation, chlamydospore formation in corn meal agar, growth at 45°C, colony characteristics on CHROMagar Candida medium, carbohydrate assimilation properties detected by API ID 32C (BioMerieux, France) system] and some molecular techniques [polymerase chain reaction (PCR) by using ITS-1, ITS-3 and ITS 4 primers, PCR-Restriction fragment length polymorphism (RFLP), PCRRFLP

  14. ANTIMICROBIAL ACTIVITY OF ETHANOL EXTRACT OF SATUREJA HORTENSIS L. TOWARDS PATHOGENIC MICROBIAL STRAINS

    Directory of Open Access Journals (Sweden)

    L. A. Kotyuk

    2014-12-01

    Full Text Available The paper provides the information on the component composition of ethereal oil of Satureja hortensis cultivated in Zhytomyr Polissya. In the ethereal oil of summer savory, 19 components were identified: carvacrol (89,07%, γ-terpinene (3,53%, α-thujone (1,7%, camphora (1,48%, terpinen-4 ol 4 (0,91%, β-bisabolen (0,56%, β-caryophyllene (0,45%, bitsiklogermakren (0,38% para-cymene (0,34%, 1,8-cineole (0,33%, trans-sabinengidrat (0.25%, 1-octen-3-ol (0.20%, spatulenol (0,18%, β-thujone (0,14%, eugenol (0,11%, geranylacetate (0,11%, humulene (0,09%, α-terpinene (0,09%, octanol-3 (0,07%. A high carvacrol content determines antimicrobial properties of summer savory. The antimicrobial activity of S. hortensis extract was studied in accordance with the common methodology of determining the sensitivity of microorganisms to antibacterial preparations. The aboveground part of plants harvested in the last ten-day period of August, in the flowering phase, was used in the experiments. The raw material was reduced to fragments of 1-1.5mm according to the requirements of pharmacopoeia. The extract of S. hortensis was obtained by the method of maceration in 40% ethyl alcohol at a ratio of 1:5 and the concentration of 200mg/ml. The availability of antimicrobial activity of extracted substances in the structure of the substances studied was determined by the way of comparison of their minimum inhibiting concentrations (MIC and minimum bactericidal/fungicidal concentrations (MBC/MFC with those in 40% ethyl alcohol. The paper investigates the biological activity of 40 % ethanol extract of Satureja hortensis herb grown under the conditions of Ukrainian Polissya as to golden staphylococcus (Staphylococcus aureus, coliform bacillus Escherichia coli, Pseudomonas aeruginosa and Candida albicans which are pathogenic in reference to other organisms. It has been shown that S. hortensis extract was characterized by antimicrobial activity since extracted substances

  15. Evaluation of the significance of cell wall polymers in flax infected with a pathogenic strain of Fusarium oxysporum.

    Science.gov (United States)

    Wojtasik, Wioleta; Kulma, Anna; Dymińska, Lucyna; Hanuza, Jerzy; Czemplik, Magdalena; Szopa, Jan

    2016-03-22

    Fusarium oxysporum infection leads to Fusarium-derived wilt, which is responsible for the greatest losses in flax (Linum usitatissimum) crop yield. Plants infected by Fusarium oxysporum show severe symptoms of dehydration due to the growth of the fungus in vascular tissues. As the disease develops, vascular browning and leaf yellowing can be observed. In the case of more virulent strains, plants die. The pathogen's attack starts with secretion of enzymes degrading the host cell wall. The main aim of the study was to evaluate the role of the cell wall polymers in the flax plant response to the infection in order to better understand the process of resistance and develop new ways to protect plants against infection. For this purpose, the expression of genes involved in cell wall polymer metabolism and corresponding polymer levels were investigated in flax seedlings after incubation with Fusarium oxysporum. This analysis was facilitated by selecting two groups of genes responding differently to the infection. The first group comprised genes strongly affected by the infection and activated later (phenylalanine ammonia lyase and glucosyltransferase). The second group comprised genes which are slightly affected (up to five times) and their expression vary as the infection progresses. Fusarium oxysporum infection did not affect the contents of cell wall polymers, but changed their structure. The results suggest that the role of the cell wall polymers in the plant response to Fusarium oxysporum infection is manifested through changes in expression of their genes and rearrangement of the cell wall polymers. Our studies provided new information about the role of cellulose and hemicelluloses in the infection process, the change of their structure and the expression of genes participating in their metabolism during the pathogen infection. We also confirmed the role of pectin and lignin in this process, indicating the major changes at the mRNA level of lignin metabolism genes

  16. Effects of single- and multi-strain probiotics on biofilm formation and in vitro adhesion to bladder cells by urinary tract pathogens.

    Science.gov (United States)

    Chapman, C M C; Gibson, G R; Rowland, I

    2014-06-01

    There is increasing evidence that probiotic bacteria can inhibit and/or prevent urinary tract infections. Possible mechanisms include prevention of adhesion of pathogens to the bladder epithelium and inhibition of biofilm formation. Currently there is interest in the comparative efficacy of single probiotics vs. strain mixtures. We have therefore tested the inhibitory activity of four single probiotics and four probiotic mixtures towards the urinary tract pathogens Escherichia coli NCTC 9001 and Enterococcus faecalis NCTC 00775. Inhibition of biofilm formation by cell-free supernatants was tested using the Crystal Violet assay, while prevention of pathogen adhesion to host cells was tested by using bladder cancer cells as a model for the human urinary tract. Under pH-controlled conditions, there was no significant inhibition of biofilm formation by any treatment. Without pH control, 5/8 treatments significantly inhibited biofilm production by E. coli, while 5/8 treatments inhibited production by E. faecalis. Using data from all Crystal Violet assays, there was no significant difference in the ability of single- and multi-strain probiotics to inhibit biofilm formation. In the cell culture assays, all treatments were able to significantly reduce numbers of pathogenic cells adhering to host cells by 2.5-3.5 logs. No significant difference was observed between the displacement caused by single strains and mixtures for either pathogen. Inhibition of biofilm seems to be a major mechanism of urinary tract pathogen exclusion, related to, and possibly dependent upon, the probiotic ability to reduce environmental pH. Exclusion via competition of binding sites is a possible in vivo mechanism for these probiotics. If an additive or synergistic effect exists between strains within a mixture, it does not manifest itself in a greater effect through these two inhibitory mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Fate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosms

    KAUST Repository

    Mantilla-Calderon, David

    2017-04-15

    The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly slower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable but no further decay was observed. Instead, 1 in every 10000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 were detected to have transferred to other native microorganisms in the sludge, or are released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24 h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater.IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study points at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic

  18. Thailandins A and B, New Polyene Macrolactone Compounds Isolated from Actinokineospora bangkokensis Strain 44EHW(T), Possessing Antifungal Activity against Anthracnose Fungi and Pathogenic Yeasts.

    Science.gov (United States)

    Intra, Bungonsiri; Greule, Anja; Bechthold, Andreas; Euanorasetr, Jirayut; Paululat, Thomas; Panbangred, Watanalai

    2016-06-29

    Two new polyene macrolactone antibiotics, thailandins A, 1, and B, 2, were isolated from the fermentation broth of rhizosphere soil-associated Actinokineospora bangkokensis strain 44EHW(T). The new compounds from this strain were purified using semipreparative HPLC and Sephadex LH-20 gel filtration while following an antifungal activity guided fractionation. Their structures were elucidated through spectroscopic techniques including UV, HR-ESI-MS, and NMR. These compounds demonstrated broad spectrum antifungal activity against fungi causing anthracnose disease (Colletotrichum gloeosporioides DoA d0762, Colletotrichum gloeosporiodes DoA c1060, and Colletotrichum capsici DoA c1511) as well as pathogenic yeasts (Candida albicans MT 2013/1, Candida parasilopsis DKMU 434, and Cryptococcus neoformans MT 2013/2) with minimum inhibitory concentrations ranging between 16 and 32 μg/mL. This is the first report of polyene antibiotics produced by Actinokineospora species as bioactive compounds against anthracnose fungi and pathogenic yeast strains.

  19. Diallylthiosulfinate (Allicin), a Volatile Antimicrobial from Garlic (Allium sativum), Kills Human Lung Pathogenic Bacteria, Including MDR Strains, as a Vapor.

    Science.gov (United States)

    Reiter, Jana; Levina, Natalja; van der Linden, Mark; Gruhlke, Martin; Martin, Christian; Slusarenko, Alan J

    2017-10-12

    Garlic ( Allium sativum ) has potent antimicrobial activity due to allicin (diallylthiosulfinate) synthesized by enzyme catalysis in damaged garlic tissues. Allicin gives crushed garlic its characteristic odor and its volatility makes it potentially useful for combating lung infections. Allicin was synthesized (>98% pure) by oxidation of diallyl disulfide by H₂O₂ using formic acid as a catalyst and the growth inhibitory effect of allicin vapor and allicin in solution to clinical isolates of lung pathogenic bacteria from the genera Pseudomonas , Streptococcus , and Staphylococcus , including multi-drug resistant (MDR) strains, was demonstrated. Minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) were determined and compared to clinical antibiotics using standard European Committee on Antimicrobial Susceptibility Testing (EUCAST) procedures. The cytotoxicity of allicin to human lung and colon epithelial and murine fibroblast cells was tested in vitro and shown to be ameliorated by glutathione (GSH). Similarly, the sensitivity of rat precision-cut lung slices (PCLS) to allicin was decreased by raising the [GSH] to the approximate blood plasma level of 1 mM. Because allicin inhibited bacterial growth as a vapor, it could be used to combat bacterial lung infections via direct inhalation. Since there are no volatile antibiotics available to treat pulmonary infections, allicin, particularly at sublethal doses in combination with oral antibiotics, could make a valuable addition to currently available treatments.

  20. Molecular characterization, phylogeny analysis and pathogenicity of a Muscovy duck adenovirus strain isolated in China in 2014

    International Nuclear Information System (INIS)

    Zhang, Xinheng; Zhong, Yangjin; Zhou, Zhenhai; Liu, Yang; Zhang, Huanmin; Chen, Feng; Chen, Weiguo; Xie, Qingmei

    2016-01-01

    This study aimed to characterize a novel adenovirus (AdV) isolated from diseased Muscovy ducks in China. After the AdV was successfully propagated in duck embryo fibroblasts, the morphological and physicochemical properties of the virions were studied by electron microscopy and different tests. The results of the analyses were in conformity with AdV properties. The full genome sequence was determined and analyzed. The new isolate (named CH-GD-12-2014) shared over 91% sequence identity with duck AdV-2 representing the species Duck aviadenovirus B. The most important distinguishing feature between the two DAdV strains was the presence of a second fiber gene in the Chinese isolate. Phylogeny reconstruction confirmed the affiliation of the virus with goose and duck AdVs in the genus Aviadenovirus. Experimental infection resulted in embryo death, and intramuscular inoculation provoked morbidity and mortality among ducks and chickens. - Highlights: • A duck adenovirus type 3 was isolated and the complete genome of DAdV-3 was obtained. • Physicochemical properties and electron microscopy were researched. • Pathogenicity of duck adenovirus type 3 was researched.

  1. Molecular characterization, phylogeny analysis and pathogenicity of a Muscovy duck adenovirus strain isolated in China in 2014

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinheng [College of Animal Science, South China Agricultural University & Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangzhou 510642 (China); Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 (China); South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou 510642 (China); Zhong, Yangjin; Zhou, Zhenhai; Liu, Yang [College of Animal Science, South China Agricultural University & Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangzhou 510642 (China); Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 (China); Zhang, Huanmin [USDA, Agriculture Research Service, Avian Disease and Oncology Laboratory, East Lansing, MI 48823 (United States); Chen, Feng [College of Animal Science, South China Agricultural University & Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangzhou 510642 (China); Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 (China); Chen, Weiguo [College of Animal Science, South China Agricultural University & Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangzhou 510642 (China); Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 (China); South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou 510642 (China); Xie, Qingmei, E-mail: qmx@scau.edu.cn [College of Animal Science, South China Agricultural University & Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Guangzhou 510642 (China); Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 (China); South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou 510642 (China)

    2016-06-15

    This study aimed to characterize a novel adenovirus (AdV) isolated from diseased Muscovy ducks in China. After the AdV was successfully propagated in duck embryo fibroblasts, the morphological and physicochemical properties of the virions were studied by electron microscopy and different tests. The results of the analyses were in conformity with AdV properties. The full genome sequence was determined and analyzed. The new isolate (named CH-GD-12-2014) shared over 91% sequence identity with duck AdV-2 representing the species Duck aviadenovirus B. The most important distinguishing feature between the two DAdV strains was the presence of a second fiber gene in the Chinese isolate. Phylogeny reconstruction confirmed the affiliation of the virus with goose and duck AdVs in the genus Aviadenovirus. Experimental infection resulted in embryo death, and intramuscular inoculation provoked morbidity and mortality among ducks and chickens. - Highlights: • A duck adenovirus type 3 was isolated and the complete genome of DAdV-3 was obtained. • Physicochemical properties and electron microscopy were researched. • Pathogenicity of duck adenovirus type 3 was researched.

  2. Diallylthiosulfinate (Allicin, a Volatile Antimicrobial from Garlic (Allium sativum, Kills Human Lung Pathogenic Bacteria, Including MDR Strains, as a Vapor

    Directory of Open Access Journals (Sweden)

    Jana Reiter

    2017-10-01

    Full Text Available Garlic (Allium sativum has potent antimicrobial activity due to allicin (diallylthiosulfinate synthesized by enzyme catalysis in damaged garlic tissues. Allicin gives crushed garlic its characteristic odor and its volatility makes it potentially useful for combating lung infections. Allicin was synthesized (>98% pure by oxidation of diallyl disulfide by H2O2 using formic acid as a catalyst and the growth inhibitory effect of allicin vapor and allicin in solution to clinical isolates of lung pathogenic bacteria from the genera Pseudomonas, Streptococcus, and Staphylococcus, including multi-drug resistant (MDR strains, was demonstrated. Minimal inhibitory (MIC and minimal bactericidal concentrations (MBC were determined and compared to clinical antibiotics using standard European Committee on Antimicrobial Susceptibility Testing (EUCAST procedures. The cytotoxicity of allicin to human lung and colon epithelial and murine fibroblast cells was tested in vitro and shown to be ameliorated by glutathione (GSH. Similarly, the sensitivity of rat precision-cut lung slices (PCLS to allicin was decreased by raising the [GSH] to the approximate blood plasma level of 1 mM. Because allicin inhibited bacterial growth as a vapor, it could be used to combat bacterial lung infections via direct inhalation. Since there are no volatile antibiotics available to treat pulmonary infections, allicin, particularly at sublethal doses in combination with oral antibiotics, could make a valuable addition to currently available treatments.

  3. Matrix approach to the simultaneous detection of multiple potato pathogens by real-time PCR.

    Science.gov (United States)

    Nikitin, M M; Statsyuk, N V; Frantsuzov, P A; Dzhavakhiya, V G; Golikov, A G

    2018-03-01

    Create a method for highly sensitive, selective, rapid and easy-to-use detection and identification of economically significant potato pathogens, including viruses, bacteria and oomycetes, be it single pathogen, or a range of various pathogens occurring simultaneously. Test-systems for real-time PCR, operating in the unified amplification regime, have been developed for Phytophthora infestans, Pectobacterium atrosepticum, Dickeya dianthicola, Dickeya solani, Ralstonia solanacearum, Pectobacterium carotovorum, Clavibacter michiganensis subsp. sepedonicus, potato viruses Y (ordinary and necrotic forms as well as indiscriminative test system, detecting all forms), A, X, S, M, potato leaf roll virus, potato mop top virus and potato spindle tuber viroid. The test-systems (including polymerase and revertase) were immobilized and lyophilized in miniature microreactors (1·2 μl) on silicon DNA/RNA microarrays (micromatrices) to be used with a mobile AriaDNA ® amplifier. Preloaded 30-reaction micromatrices having shelf life of 3 and 6 months (for RNA- and DNA-based pathogens, respectively) at room temperature with no special conditions were successfully tested on both reference and field samples in comparison with traditional ELISA and microbiological methods, showing perfect performance and sensitivity (1 pg). The accurate, rapid and user-friendly diagnostic system in a micromatrix format may significantly contribute to pathogen screening and phytopathological studies. © 2018 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd on behalf of The Society for Applied Microbiology.

  4. Detection of multiple potentially pathogenic bacteria in Matang mangrove estuaries, Malaysia.

    Science.gov (United States)

    Ghaderpour, Aziz; Mohd Nasori, Khairul Nazrin; Chew, Li Lee; Chong, Ving Ching; Thong, Kwai Lin; Chai, Lay Ching

    2014-06-15

    The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Strain-balanced InGaN/GaN multiple quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Van Den Broeck, D. M.; Hosalli, A. M.; Bedair, S. M. [Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Bharrat, D.; El-Masry, N. A. [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-07-21

    InGaN/GaN multiple quantum well (MQW) structures suffer from a high amount of compressive strain in the InGaN wells and the accompanied piezoelectric field resulting in both a blue shift in emission and a reduction of emission intensity. We report the growth of In{sub x}Ga{sub 1−x}N/GaN “strain-balanced” multiple quantum wells (SBMQWs) grown on thick In{sub y}Ga{sub 1−y}N templates for x > y by metal organic chemical vapor deposition. SBMQWs consist of alternating layers of In{sub x}Ga{sub 1−x}N wells and GaN barriers under compressive and tensile stress, respectively, which have been lattice matched to a thick In{sub y}Ga{sub 1−y}N template. Growth of the In{sub y}Ga{sub 1−y}N template is also detailed in order to achieve thick, relaxed In{sub y}Ga{sub 1−y}N grown on GaN without the presence of V-grooves. When compared to conventional In{sub x}Ga{sub 1−x}N/GaN MQWs grown on GaN, the SBMQW structures exhibit longer wavelength emission and higher emission intensity for the same InN mole fraction due to a reduction in the well strain and piezoelectric field. By matching the average lattice constant of the MQW active region to the lattice constant of the In{sub y}Ga{sub 1−y}N template, essentially an infinite number of periods can be grown using the SBMQW growth method without relaxation-related effects. SBMQWs can be utilized to achieve longer wavelength emission in light emitting diodes without the use of excess indium and can be advantageous in addressing the “green gap.”.

  6. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species.

    Directory of Open Access Journals (Sweden)

    Riccardo Baroncelli

    Full Text Available Fragaria × ananassa (common name: strawberry is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l. is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production.

  7. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species

    Science.gov (United States)

    Baroncelli, Riccardo; Zapparata, Antonio; Sarrocco, Sabrina; Sukno, Serenella A.; Lane, Charles R.; Thon, Michael R.; Vannacci, Giovanni; Holub, Eric; Sreenivasaprasad, Surapareddy

    2015-01-01

    Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production. PMID:26086351

  8. The pathogenic potential of different pulsed-field gel electrophoresis types of Listeria monocytogenes strains isolated from food in Northeast Bosnia and Herzegovina.

    Science.gov (United States)

    Hodžić, Snjezana; Hukić, Mirsada; Franciosa, Giovanna; Aureli, Paolo

    2011-09-01

    Listeria monocytogenes is often present in meat and meat products that are sold in the area of northeast Bosnia and Herzegovina. The major objective of this study was to examine the virulence of L. monocytogenes strains isolated from these types of food in that geographic area. Polymerase chain reaction was used to detect eight genes responsible for virulence of this pathogen, namely, prfA, inlA, inlB, hly, plcA, plcB, actA, and mpl. All examined isolates were confirmed to possess the eight virulence genes. Ten different pulsed-field gel electrophoresis (PFGE) macrorestriction profiles were recognized among 19 L. monocytogenes strains after restriction with two different endonucleases (ApaI and AscI). The pathogenicity of three different PFGE types of L. monocytogenes was confirmed through in vivo tests, which were performed on female white mice (Pasteur strain), and it ranged from 3.55 × 10(8) LD50 to 1.58 × 10(10) LD50. All of the three different PFGE types of L. monocytogenes were regarded as moderately virulent in relation to the reference strain L. monocytogenes Scott A. This result might be one of the reasons for the absence of reported listeriosis in northeast Bosnia and Herzegovina, despite the high degree of food contamination with this pathogen.

  9. Genome analysis of multiple pathogenic isolates of Streptococcus agalactiae : Implications for the microbial "pan-genome"

    NARCIS (Netherlands)

    Tettelin, H; Masignani, [No Value; Cieslewicz, MJ; Donati, C; Medini, D; Ward, NL; Angiuoli, SV; Crabtree, J; Jones, AL; Durkin, AS; DeBoy, RT; Davidsen, TM; Mora, M; Scarselli, M; Ros, IMY; Peterson, JD; Hauser, CR; Sundaram, JP; Nelson, WC; Madupu, R; Brinkac, LM; Dodson, RJ; Rosovitz, MJ; Sullivan, SA; Daugherty, SC; Haft, DH; Selengut, J; Gwinn, ML; Zhou, LW; Zafar, N; Khouri, H; Radune, D; Dimitrov, G; Watkins, K; O'Connor, KJB; Smith, S; Utterback, TR; White, O; Rubens, CE; Grandi, G; Madoff, LC; Kasper, DL; Telford, JL; Wessels, MR; Rappuoli, R; Fraser, CM

    2005-01-01

    The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design. Unfortunately, the sequence of a single genome does not reflect how genetic variability drives pathogenesis within a bacterial species and

  10. Transcriptional and Antagonistic Responses of Biocontrol Strain Lysobacter enzymogenes OH11 to the Plant Pathogenic Oomycete Pythium aphanidermatum

    Directory of Open Access Journals (Sweden)

    Yangyang Zhao

    2017-06-01

    Full Text Available Lysobacter enzymogenes is a ubiquitous, beneficial, plant-associated bacterium emerging as a novel biological control agent. It has the potential to become a new source of antimicrobial secondary metabolites such as the Heat-Stable Antifungal Factor (HSAF, which is a broad-spectrum antimycotic with a novel mode of action. However, very little information about how L. enzymogenes detects and responds to fungi or oomycetes has been reported. An in vitro confrontation bioassay between the pathogenic oomycete Pythium aphanidermatum and the biocontrol bacterial strain L. enzymogenes OH11 was used to analyze the transcriptional changes in the bacteria that were induced by the oomycetes. Analysis was performed at three time points of the interaction, starting before inhibition zone formation until inhibition zone formation. A L. enzymogenes OH11 DNA microarray was constructed for the analysis. Microarray analysis indicated that a wide range of genes belonging to 14 diverse functions in L. enzymogenes were affected by P. aphanidermatum as critical antagonistic effects occurred. L. enzymogenes detected and responded to the presence of P. aphanidermatum early, but alteration of gene expression typically occurred after inhibition zone formation. The presence of P. aphanidermatum increased the twitching motility and HSAF production in L. enzymogenes. We also performed a contact interaction between L. enzymogenes and P. aphanidermatum, and found that HSAF played a critical role in the interaction. Our experiments demonstrated that L. enzymogenes displayed transcriptional and antagonistic responses to P. aphanidermatum in order to gain advantages in the competition with this oomycete. This study revealed new insights into the interactions between bacteria and oomycete.

  11. Antifungal mechanism of the combination of Cinnamomum verum and Pelargonium graveolens essential oils with fluconazole against pathogenic Candida strains.

    Science.gov (United States)

    Essid, Rym; Hammami, Majdi; Gharbi, Dorra; Karkouch, Ines; Hamouda, Thouraya Ben; Elkahoui, Salem; Limam, Ferid; Tabbene, Olfa

    2017-09-01

    The present study aimed to investigate the anti-Candida activity of ten essential oils (EOs) and to evaluate their potential synergism with conventional drugs. The effect on secreted aspartic protease (SAP) activity and the mechanism of action were also explored. The antifungal properties of essential oils were investigated using standard micro-broth dilution assay. Only Cinnamomum verum, Thymus capitatus, Syzygium aromaticum, and Pelargonium graveolens exhibited a broad spectrum of activity against a variety of pathogenic Candida strains. Chemical composition of active essential oils was performed by gas chromatography-mass spectrometry (GC-MS). Synergistic effect was observed with the combinations C. verum/fluconazole and P. graveolens/fluconazole, with FIC value 0.37. Investigation of the mechanism of action revealed that C. verum EO reduced the quantity of ergosterol to 83%. A total inhibition was observed for the combination C. verum/fluconazole. However, P. graveolens EO may disturb the permeability barrier of the fungal cell wall. An increase of MIC values of P. graveolens EO and the combination with fluconazole was observed with osmoprotectants (sorbitol and PEG6000). Furthermore, the combination with fluconazole may affect ergosterol biosynthesis and disturb fatty acid homeostasis in C. albicans cells as the quantity of ergosterol and oleic acid was reduced to 52.33 and 72%, respectively. The combination of P. graveolens and C. verum EOs with fluconazole inhibited 78.31 and 64.72% SAP activity, respectively. To our knowledge, this is the first report underlying the mechanism of action and the inhibitory effect of SAP activity of essential oils in synergy with fluconazole. Naturally occurring phytochemicals C. verum and P. graveolens could be effective candidate to enhance the efficacy of fluconazole-based therapy of C. albicans infections.

  12. Bovine digital dermatitis: Possible pathogenic consortium consisting of Dichelobacter nodosus and multiple Treponema species

    DEFF Research Database (Denmark)

    Rasmussen, Marianne; Capion, Nynne; Schou, Kirstine Klitgaard

    2012-01-01

    not colonized by bacteria while only four samples were found normal. We hypothesise that external noxious stimuli allow D. nodosus to break down the epidermal barrier creating a suitable environment for the secondary invaders, Treponema species, which gradually take over the infection site. The variety...... and different distribution of treponemes in the DD lesions observed in this study, suggests that most of the Treponema phylotypes have the potential to be pathogenic....

  13. Phytotoxic activity against Bromus tectorum for secondary metabolites of a seed-pathogenic Fusarium strain belonging to the F. tricinctum species complex.

    Science.gov (United States)

    Masi, Marco; Meyer, Susan; Pescitelli, Gennaro; Cimmino, Alessio; Clement, Suzette; Peacock, Beth; Evidente, Antonio

    2017-12-01

    The winter annual grass Bromus tectorum (cheatgrass) has become highly invasive in semiarid ecosystems of western North America. In these areas, a natural phenomenon, complete cheatgrass stand failure ('die-off'), is apparently caused by a complex interaction among soilborne fungal pathogens. Several Fusarium strains belonging to the Fusarium tricinctum species complex were isolated from these soils and found to be pathogenic on B. tectorum seeds. One of these strains was produced in cheatgrass seed culture to evaluate its ability to produce phytotoxins. Six metabolites were isolated and identified by spectroscopic methods (essentially 1D and 2D NMR and ESIMS) as acuminatopyrone (1), blumenol A (2), chlamydosporol (3), isochlamydosporol (4), ergosterol (5) and 4-hydroxybenzaldehyde (6). Upon testing against B. tectorum in a seedling bioassay, (6) the coleoptile and radicle length of cheatgrass seedlings were significantly reduced. Compounds 1 and 2 showed moderate activity, while 3-5 were not significantly different from the control.

  14. Normalized Rotational Multiple Yield Surface Framework (NRMYSF) stress-strain curve prediction method based on small strain triaxial test data on undisturbed Auckland residual clay soils

    Science.gov (United States)

    Noor, M. J. Md; Ibrahim, A.; Rahman, A. S. A.

    2018-04-01

    Small strain triaxial test measurement is considered to be significantly accurate compared to the external strain measurement using conventional method due to systematic errors normally associated with the test. Three submersible miniature linear variable differential transducer (LVDT) mounted on yokes which clamped directly onto the soil sample at equally 120° from the others. The device setup using 0.4 N resolution load cell and 16 bit AD converter was capable of consistently resolving displacement of less than 1µm and measuring axial strains ranging from less than 0.001% to 2.5%. Further analysis of small strain local measurement data was performed using new Normalized Multiple Yield Surface Framework (NRMYSF) method and compared with existing Rotational Multiple Yield Surface Framework (RMYSF) prediction method. The prediction of shear strength based on combined intrinsic curvilinear shear strength envelope using small strain triaxial test data confirmed the significant improvement and reliability of the measurement and analysis methods. Moreover, the NRMYSF method shows an excellent data prediction and significant improvement toward more reliable prediction of soil strength that can reduce the cost and time of experimental laboratory test.

  15. Protection of mice against lethal infection with highly pathogenic H7N7 influenza A virus by using a recombinant low-pathogenicity vaccine strain.

    NARCIS (Netherlands)

    V.J. Munster (Vincent); M.I. Spronken (Monique); T.M. Bestebroer (Theo); C. Baas (Chantal); W.E.Ph. Beyer (Walter); G.F. Rimmelzwaan (Guus); A.D.M.E. Osterhaus (Albert); R.A.M. Fouchier (Ron); E. de Wit (Emmie)

    2005-01-01

    textabstractIn 2003, an outbreak of highly pathogenic avian influenza occurred in The Netherlands. The avian H7N7 virus causing the outbreak was also detected in 88 humans suffering from conjunctivitis or mild respiratory symptoms and one person who died of pneumonia and acute respiratory distress

  16. Developing the multiple stress-strain creep recovery (MS-SCR) test

    Science.gov (United States)

    Elnasri, Mahmoud; Airey, Gordon; Thom, Nick

    2018-04-01

    While most published work from Europe has been concerned with evaluating binders' resistance to rutting based on their stiffness (deformation resistance), work originating in the US has mainly been concerned with ranking binders based on their recoverability in a multiple stress form. This paper details the design of a new modified multiple stress-strain creep recovery (MS-SCR) test. The test is designed to evaluate binders' rutting resistance based on two rutting resistance mechanisms: stiffness and recoverability. A preliminary investigation is presented in this paper followed by details of the design of the new modified test. A 40/60 penetration grade bitumen and bitumen-filler mastics prepared with three filler concentrations (35%, 50%, and 65% filler content by mass of mastic) were tested. In addition, two polymer modified bitumens (PMBs) using the same base bitumen type were examined for validation. Two parameters are introduced to characterise the short and long recovery in the new test. In terms of stiffness, the test allows the behaviour of binders at different stress levels and loading cycles to be studied and produces a new parameter that can quantify the degree of modification. Finally, a relationship between nonlinearity and normal force in the test was investigated.

  17. The biofilm formation ability of Listeria monocytogenes isolated from meat, poultry, fish and processing plant environments is related to serotype and pathogenic profile of the strains

    Directory of Open Access Journals (Sweden)

    Domenico Meloni

    2012-10-01

    Full Text Available In the present study, the relationships between serotype, pathogenic profile and in vitro biofilm formation of 106 Listeria monocytogenes strains, having no epidemiological correlation and isolated from different environmental and food sources, were analyzed. The quantitative assessment of the in vitro biofilm formation was carried out by using a microtiter plate assay with spectrophotometric reading (OD620. The isolates were also submitted to serogrouping using the target genes lmo0737, lmo1118, ORF2819, ORF2110, prs, and to the evaluation of the presence of the following virulence genes: prfA, hlyA, rrn, inlA, inlB, iap, plcA, plcB, actA and mpl, by multiplex PCRs. The 62% of the strains showed weak or moderate in vitro ability in biofilm formation, in particular serotypes 1/2b and 4b, frequently associated with sporadic or epidemic listeriosis cases. The 25% of these isolates showed polymorphism for the actA gene, producing a fragment of 268-bp instead of the expected 385-bp. The deletion of nucleotides in this gene seems to be related to enhanced virulence properties among these strains. Strains belonging to serotypes associated with human infections and characterized by pathogenic potential are capable to persist within the processing plants forming biofilm.

  18. Molecular, morphological and pathogenic characterization of six strains of Metarhizium spp. (Deuteromycotina: Hyphomycetes for the control of Aegorhinus superciliosus (Coleoptera: Curculionidae

    Directory of Open Access Journals (Sweden)

    María Sepúlveda

    2016-03-01

    Full Text Available Aegorhinus superciliosus is an important pest on blueberry (Vaccinium corymbosum L. and other fruit trees. The use of entomopathogenic fungi as Metarhizium spp. has been evaluated for the control of this insect, but variability has been observed among different strains. The aim of this study was to characterize six promising strains of Metarhizium spp. for the control of A. superciliosus. The studied strains were QuM173c, Qu-M363, Qu-M171a, Qu-M156a, Qu-M421, and Qu-M430, all of which belonged to the Chilean Collection of Microbial Genetic Resources (ChCMGR of the Institute de Investigaciones Agropecuarias (INIA, Chile. Molecular characterization was made by sequencing the ITS region (Internal Transcribed Spacers, ITS-5.8S rDNA. The morphology of conidia was evaluated through scanning electron microscopy and radial colony growth was evaluated in potato dextrose agar (PDA, Sabouraud dextrose agar (SDA, agar enriched with larvae of Galleria mellonella (Lepidoptera: Pyralidae (GA, and agar enriched with adults of A. superciliosus (AA. Pathogenicity was studied based on mortality of adults of A. superciliosus inoculated with conidia. Sequencing of the ITS-5.8S rDNA region indicates that the strains belong to the clade of M. anisopliae var. anisopliae, except for Qu-M171a, which was identified as M. anisopliae var. lepidiotum. Conidia average length for the six strains was 5.09 pm and average conidia width was 1.92 pm. Radial colony growth differences were observed between strains (p < 0.01 and between different growth media (p < 0.01. The strains exhibited the highest colony growth in the GA medium, while in the AA medium they showed the lowest (p < 0.01. Pathogenicity tests show that Qu-M430 reached a 90% mortality rate (p < 0.01. Results show that there is variability between the studied strains, which is expressed in their morphology, molecular characteristics and pathogenicity towards A. superciliosus.

  19. Pathogenicity of Genetically Similar, H5N1 Highly Pathogenic Avian Influenza Virus Strains in Chicken and the Differences in Sensitivity among Different Chicken Breeds

    Science.gov (United States)

    Matsuu, Aya; Kobayashi, Tomoko; Patchimasiri, Tuangthong; Shiina, Takashi; Suzuki, Shingo; Chaichoune, Kridsada; Ratanakorn, Parntep; Hiromoto, Yasuaki; Abe, Haruka; Parchariyanon, Sujira; Saito, Takehiko

    2016-01-01

    Differences in the pathogenicity of genetically closely related H5N1 highly pathogenic avian influenza viruses (HPAIVs) were evaluated in White Leghorn chickens. These viruses varied in the clinical symptoms they induced, including lethality, virus shedding, and replication in host tissues. A comparison of the host responses in the lung, brain, and spleen suggested that the differences in viral replication efficiency were related to the host cytokine response at the early phase of infection, especially variations in the proinflammatory cytokine IL-6. Based on these findings, we inoculated the virus that showed the mildest pathogenicity among the five tested, A/pigeon/Thailand/VSMU-7-NPT/2004, into four breeds of Thai indigenous chicken, Phadu-Hung-Dang (PHD), Chee, Dang, and Luang-Hung-Khao (LHK), to explore effects of genetic background on host response. Among these breeds, Chee, Dang, and LHK showed significantly longer survival times than White Leghorns. Virus shedding from dead Thai indigenous chickens was significantly lower than that from White Leghorns. Although polymorphisms were observed in the Mx and MHC class I genes, there was no significant association between the polymorphisms in these loci and resistance to HPAIV. PMID:27078641

  20. Infection studies with two highly pathogenic avian influenza strains (Vietnamese and Indonesian) in Pekin ducks (Anas platyrhynchos), with particular reference to clinical disease, tissue tropism and viral shedding.

    Science.gov (United States)

    Bingham, John; Green, Diane J; Lowther, Sue; Klippel, Jessica; Burggraaf, Simon; Anderson, Danielle E; Wibawa, Hendra; Hoa, Dong Manh; Long, Ngo Thanh; Vu, Pham Phong; Middleton, Deborah J; Daniels, Peter W

    2009-08-01

    Pekin ducks were infected by the mucosal route (oral, nasal, ocular) with one of two strains of Eurasian lineage H5N1 highly pathogenic avian influenza virus: A/Muscovy duck/Vietnam/453/2004 and A/duck/Indramayu/BBVW/109/2006 (from Indonesia). Ducks were killed humanely on days 1, 2, 3, 5 and 7 after challenge, or whenever morbidity was severe enough to justify euthanasia. Morbidity was recorded by observation of clinical signs and cloacal temperatures; the disease was characterized by histopathology; tissue tropism was studied by immunohistochemistry and virus titration on tissue samples; and viral shedding patterns were determined by virus isolation and titration of oral and cloacal swabs. The Vietnamese strain caused severe morbidity with fever and depression; the Indonesian strain caused only transient fever. Both viruses had a predilection for a similar range of tissue types, but the quantity of tissue antigen and tissue virus titres were considerably higher with the Vietnamese strain. The Vietnamese strain caused severe myocarditis and skeletal myositis; both strains caused non-suppurative encephalitis and a range of other inflammatory reactions of varying severity. The principal epithelial tissue infected was that of the air sacs, but antigen was not abundant. Epithelium of the turbinates, trachea and bronchi had only rare infection with virus. Virus was shed from both the oral and cloacal routes; it was first detected 24 h after challenge and persisted until day 5 after challenge. The higher prevalence of virus from swabs from ducks infected with the Vietnamese strain indicates that this strain may be more adapted to ducks than the Indonesia strain.

  1. Capsid proteins from field strains of foot-and-mouth disease virus confer a pathogenic phenotype in cattle on an attenuated, cell-culture-adapted virus

    DEFF Research Database (Denmark)

    Bøtner, Anette; Kakker, Naresh K.; Barbezange, Cyril

    2011-01-01

    Chimeric foot-and-mouth disease viruses (FMDVs) have been generated from plasmids containing full-length FMDV cDNAs and characterized. The parental virus cDNA was derived from the cell-culture-adapted O1Kaufbeuren B64 (O1K B64) strain. Chimeric viruses, containing capsid coding sequences derived...... cells than the rescued parental O1K B64 virus. The two chimeric viruses displayed the expected antigenicity in serotype-specific antigen ELISAs. Following inoculation of each virus into cattle, the rescued O1K B64 strain proved to be attenuated whereas, with each chimeric virus, typical clinical signs...... region within the O1K B64 strain that inhibits replication in cattle. These chimeric infectious cDNA plasmids provide a basis for the analysis of FMDV pathogenicity and characterization of receptor utilization in vivo....

  2. Analysis of the genome sequence of the pathogenic Muscovy duck parvovirus strain YY reveals a 14-nucleotide-pair deletion in the inverted terminal repeats.

    Science.gov (United States)

    Wang, Jianye; Huang, Yu; Zhou, Mingxu; Zhu, Guoqiang

    2016-09-01

    Genomic information about Muscovy duck parvovirus is still limited. In this study, the genome of the pathogenic MDPV strain YY was sequenced. The full-length genome of YY is 5075 nucleotides (nt) long, 57 nt shorter than that of strain FM. Sequence alignment indicates that the 5' and 3' inverted terminal repeats (ITR) of strain YY contain a 14-nucleotide-pair deletion in the stem of the palindromic hairpin structure in comparison to strain FM and FZ91-30. The deleted region contains one "E-box" site and one repeated motif with the sequence "TTCCGGT" or "ACCGGAA". Phylogenetic trees constructed based the protein coding genes concordantly showed that YY, together with nine other MDPV isolates from various places, clustered in a separate branch, distinct from the branch formed by goose parvovirus (GPV) strains. These results demonstrate that, despite the distinctive deletion, the YY strain still belongs to the classical MDPV group. Moreover, the deletion of ITR may contribute to the genome evolution of MDPV under immunization pressure.

  3. Multiple-strain Trichophyton mentagrophytes infection in a silver fox (Vulpes vulpes) from a breeding farm.

    Science.gov (United States)

    Gnat, Sebastian; Nowakiewicz, Aneta; Lagowski, Dominik; Troscianczyk, Aleksandra; Zieba, Przemyslaw

    2018-03-08

    Dermatophyte infections are extremely frequent worldwide, and their epidemiological features and distribution make them one of the most frequent infections all over the world. We identified and analysed multiform T. mentagrophytes strains isolated from a silver fox (Vulpes vulpes) kept on a breeding farm. Identification of dermatophyte strains was carried out traditionally by correlating both the clinical manifestations of the infection with a micro- and macroscopic examination. To confirm the species affiliation fully, molecular differentiation methods were used. DNA was isolated from the dermatophytes with the phenol-chloroform method. The reaction of chitin synthase 1 (chs1) amplification was carried out to confirm the dermatophytes. The phylogenetic analysis was based on the ITS sequences. The polymerase chain reaction melting profile (PCR-MP) procedure was used for differentiation of dermatophyte genomes. Direct analysis of the material sampled from the clinical lesions revealed the presence of arthrospores in the samples collected from all animals with skin lesions. The macromorphology of the colonies obtained from material sampled from the same individual was not homogeneous. The PCR-MP electrophoregram indicated high variability of their genomes. Although the dermatophytes were isolated from one infected fox, no two identical genomic profiles were obtained. The PCR-MP result corresponds with the phenotypic diversity of the isolates. The findings about the multiple dermatophyte infection in one individual complicate any future epidemiology work and other clinical investigation. Previously, using only morphological characteristics, it had been assumed that one fungal isolate per patient could be diagnosed. The novel findings encourage application of the newly developed molecular typing methods in the diagnosis of dermatophytosis.

  4. Quantification of carotid artery plaque stability with multiple region of interest based ultrasound strain indices and relationship with cognition

    Science.gov (United States)

    Meshram, N. H.; Varghese, T.; Mitchell, C. C.; Jackson, D. C.; Wilbrand, S. M.; Hermann, B. P.; Dempsey, R. J.

    2017-08-01

    Vulnerability and instability in carotid artery plaque has been assessed based on strain variations using noninvasive ultrasound imaging. We previously demonstrated that carotid plaques with higher strain indices in a region of interest (ROI) correlated to patients with lower cognition, probably due to cerebrovascular emboli arising from these unstable plaques. This work attempts to characterize the strain distribution throughout the entire plaque region instead of being restricted to a single localized ROI. Multiple ROIs are selected within the entire plaque region, based on thresholds determined by the maximum and average strains in the entire plaque, enabling generation of additional relevant strain indices. Ultrasound strain imaging of carotid plaques, was performed on 60 human patients using an 18L6 transducer coupled to a Siemens Acuson S2000 system to acquire radiofrequency data over several cardiac cycles. Patients also underwent a battery of neuropsychological tests under a protocol based on National Institute of Neurological Disorders and Stroke and Canadian Stroke Network guidelines. Correlation of strain indices with composite cognitive index of executive function revealed a negative association relating high strain to poor cognition. Patients grouped into high and low cognition groups were then classified using these additional strain indices. One of our newer indices, namely the average L  -  1 norm with plaque (AL1NWP) presented with significantly improved correlation with executive function when compared to our previously reported maximum accumulated strain indices. An optimal combination of three of the new indices generated classifiers of patient cognition with an area under the curve (AUC) of 0.880, 0.921 and 0.905 for all (n  =  60), symptomatic (n  =  33) and asymptomatic patients (n  =  27) whereas classifiers using maximum accumulated strain indices alone provided AUC values of 0.817, 0.815 and 0

  5. Strains of avian paramyxovirus type 1 of low pathogenicity for chickens isolated from poultry and wild birds in Denmark

    DEFF Research Database (Denmark)

    Jørgensen, Poul Henrik; Handberg, Kurt; Ahrens, Peter

    2004-01-01

    Twenty-one strains of avian paramyxovirus type 1 of low virulence for chickens were isolated in Denmark between 1996 and the beginning of 2003. The low virulence of the strains was demonstrated by sequencing the fusion (F) gene at the cleavage site motif and in some cases by determining the intra......Twenty-one strains of avian paramyxovirus type 1 of low virulence for chickens were isolated in Denmark between 1996 and the beginning of 2003. The low virulence of the strains was demonstrated by sequencing the fusion (F) gene at the cleavage site motif and in some cases by determining...

  6. Genomic analysis and pathogenic characteristics of Type 2 porcine reproductive and respiratory syndrome virus nsp2 deletion strains isolated in Korea.

    Science.gov (United States)

    Choi, Hwan-Won; Nam, Eeuri; Lee, Yoo Jin; Noh, Yun-Hee; Lee, Seung-Chul; Yoon, In-Joong; Kim, Hyun-Soo; Kang, Shien-Young; Choi, Young-Ki; Lee, Changhee

    2014-06-04

    Porcine reproductive and respiratory syndrome virus (PRRSV) is a globally ubiquitous swine virus that exhibits genetic and pathogenic heterogeneity among isolates. The present study was conducted to determine the complete genome sequence and pathogenicity of two Korean type 2 PRRSV nonstructural protein 2 (nsp2) deletion mutants, CA-2 and KNU-12-KJ4. The full-length genomes of CA-2 and KNU-12-KJ4 were determined to be 15,018 and 15,019 nucleotides in length, excluding the poly(A) tail, respectively, which were 393- or 392-nucleotide shorter than that of the type 2 NA prototype strain VR-2332 due to the presence of notable large deletions within the nsp2 gene. The genomes of CA-2 and KNU-12-KJ4 consisted of a 189- or 190-nucleotide 5' untranslated region (UTR), a 14,677-nucleotide protein-coding region, and a 151-nucleotide 3' UTR. Whole genome evaluation revealed that the nucleotide sequences of CA-2 and KNU-12-KJ4 are most similar to each other (10.7% sequence divergence), and then to the Korean strain CA-1 (11.3% sequence divergence) and the US strain MN184C (13.1% sequence divergence), respectively. To evaluate the in vitro immunity of nsp2 deletion variants, we sought to explore alteration of inflammatory cytokine and chemokine expression in PAM-pCD163 cells infected with each virus strain using quantitative real-time RT-PCR. Cytokine genes including IL-8, IL-10, and TNF-α, and chemokines such as MCP-1 and RANTES were found to be significantly elevated in nsp2 deletion virus-infected PAM cells. In contrast, expression of interferons (IFN-β, γ, and λ) and antiviral genes including ISG-15, -54, and -56 were unchanged or down-regulated in PAM cells infected with the nsp2 deletion mutants. Animal studies to assess the pathogenicity of nsp2 deletion PRRSVs demonstrated that both CA-2 and KNU-12-KJ4 strains notably produce weight loss in infected pigs. Furthermore, the nsp2 deletion mutants replicated well in pigs with significantly increased and prolonged

  7. An Epithelial Integrin Regulates the Amplitude of Protective Lung Interferon Responses against Multiple Respiratory Pathogens.

    Directory of Open Access Journals (Sweden)

    Victoria A Meliopoulos

    2016-08-01

    Full Text Available The healthy lung maintains a steady state of immune readiness to rapidly respond to injury from invaders. Integrins are important for setting the parameters of this resting state, particularly the epithelial-restricted αVβ6 integrin, which is upregulated during injury. Once expressed, αVβ6 moderates acute lung injury (ALI through as yet undefined molecular mechanisms. We show that the upregulation of β6 during influenza infection is involved in disease pathogenesis. β6-deficient mice (β6 KO have increased survival during influenza infection likely due to the limited viral spread into the alveolar spaces leading to reduced ALI. Although the β6 KO have morphologically normal lungs, they harbor constitutively activated lung CD11b+ alveolar macrophages (AM and elevated type I IFN signaling activity, which we traced to the loss of β6-activated transforming growth factor-β (TGF-β. Administration of exogenous TGF-β to β6 KO mice leads to reduced numbers of CD11b+ AMs, decreased type I IFN signaling activity and loss of the protective phenotype during influenza infection. Protection extended to other respiratory pathogens such as Sendai virus and bacterial pneumonia. Our studies demonstrate that the loss of one epithelial protein, αVβ6 integrin, can alter the lung microenvironment during both homeostasis and respiratory infection leading to reduced lung injury and improved survival.

  8. Molecular Occurrence of Enterocin A Gene among Enterococcus faecium Strains Isolated from Gastro-Intestinal Tract and Antimicrobial Effect of this Bacteriocin Against Clinical Pathogens

    Directory of Open Access Journals (Sweden)

    Mitra Salehi

    2014-06-01

    Materials and Methods: In this study occurrence of class II enterocin structural gene (enterocin A in a target of 42 Enterococcus faecium strains, isolated from gastrointestinal tract of animal have been surveyed. E. faecium identification and occurrence of enterocin A gene was performed by PCR method. Cell-free neutralized supernatant of gene positive strains was used to test bacteriocin production and antimicrobial spectrum of supernatant was assayed by wall diffusion method on the gram-positive and negative indicators bacteriaResults: Based on our results, 73.8% of isolated strains had enterocin A gene that they inhibited growth of indicator bacteria such as clinical strain of Pseudomonas aeruginosa, Salmonella enteric PTCC1709, Listeria monocytogenes, Bacillus cereus and Bacillus subtilis.Conclusions: Studied enterocins have growth inhibitory spectrum on Gram-positive and Gram-negative bacteria especially against pathogenic bacteria in the gastrointestinal tract. Therefore, these strains have the potential to explore and use as, alternative antimicrobial compound and bio-preservatives in food or feed or as probiotics.

  9. Large area strain analysis using scanning transmission electron microscopy across multiple images

    International Nuclear Information System (INIS)

    Oni, A. A.; Sang, X.; LeBeau, J. M.; Raju, S. V.; Saxena, S.; Dumpala, S.; Broderick, S.; Rajan, K.; Kumar, A.; Sinnott, S.

    2015-01-01

    Here, we apply revolving scanning transmission electron microscopy to measure lattice strain across a sample using a single reference area. To do so, we remove image distortion introduced by sample drift, which usually restricts strain analysis to a single image. Overcoming this challenge, we show that it is possible to use strain reference areas elsewhere in the sample, thereby enabling reliable strain mapping across large areas. As a prototypical example, we determine the strain present within the microstructure of a Ni-based superalloy directly from atom column positions as well as geometric phase analysis. While maintaining atomic resolution, we quantify strain within nanoscale regions and demonstrate that large, unit-cell level strain fluctuations are present within the intermetallic phase

  10. Pathogenicity of Vibrio anguillarum serogroup O1 strains compared to plasmids, outer membrane protein profiles and siderophore production

    DEFF Research Database (Denmark)

    Pedersen, K.; Gram, Lone; Austin, D.A.

    1997-01-01

    The virulence of 18 strains of Vibrio anguillarum serogroup 01 was compared to plasmid content, expression of siderophores and outer membrane proteins. All strains, irrespective of plasmid content, produced siderophores and inducible outer membrane proteins under iron-limited conditions. Only str...

  11. Multiple-host pathogens in domestic hunting dogs in Nicaragua's Bosawás Biosphere Reserve.

    Science.gov (United States)

    Fiorello, Christine V; Straub, Mary H; Schwartz, Laura M; Liu, James; Campbell, Amanda; Kownacki, Alexa K; Foley, Janet E

    2017-03-01

    Nicaragua's Bosawás Biosphere Reserve is a vast forested area inhabited largely by indigenous Mayangna and Miskitu people. Most Bosawás residents rely on subsistence hunting and swidden agriculture, and hunting dogs are important for finding and securing wild game. We investigated the health of hunting dogs in three communities differing in location, size, and economy. Dogs in all communities were nutritionally compromised and experienced a heavy burden of disease. Seroprevalence of canine distemper, canine parvovirus, Rickettsia rickettsii, and Leptospira spp. exceeded 50% of dogs. At least one dog was actively shedding leptospires in urine, and many dogs were anemic and/or dehydrated. These dogs interact with wildlife in the forest and humans and domestic livestock in the communities, and may therefore serve as sources of zoonotic and wildlife diseases. Bosawás represents one of the largest intact tracts of habitat for jaguars (Panthera onca) in Central America, and given that these communities are located within the forest, jaguars may be at risk from disease spillover from hunting dogs. Dog owners reported that four of 49 dogs had been attacked and killed by jaguars in the past year, and that retaliatory killing of jaguars was sometimes practiced. Disease spillover from dogs to wildlife could occur both in the course of dogs' hunting activities as well as during jaguar attacks. A better understanding of dog depredation by jaguars, pathogen exposure in jaguars, and a management strategy for the hunting dog population, are urgently needed to mitigate these dual threats to jaguars, improve the lives of hunting dogs, and safeguard the health of their owners. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Attenuation of pathogenic Rift Valley fever virus strain through the chimeric S-segment encoding sandfly fever phlebovirus NSs or a dominant-negative PKR.

    Science.gov (United States)

    Nishiyama, Shoko; Slack, Olga A L; Lokugamage, Nandadeva; Hill, Terence E; Juelich, Terry L; Zhang, Lihong; Smith, Jennifer K; Perez, David; Gong, Bin; Freiberg, Alexander N; Ikegami, Tetsuro

    2016-11-16

    Rift Valley fever is a mosquito-borne zoonotic disease affecting ruminants and humans. Rift Valley fever virus (RVFV: family Bunyaviridae, genus Phlebovirus) causes abortions and fetal malformations in ruminants, and hemorrhagic fever, encephalitis, or retinitis in humans. The live-attenuated MP-12 vaccine is conditionally licensed for veterinary use in the US. However, this vaccine lacks a marker for the differentiation of vaccinated from infected animals (DIVA). NSs gene is dispensable for RVFV replication, and thus, rMP-12 strains lacking NSs gene is applicable to monitor vaccinated animals. However, the immunogenicity of MP-12 lacking NSs was not as high as parental MP-12. Thus, chimeric MP-12 strains encoding NSs from either Toscana virus (TOSV), sandfly fever Sicilian virus (SFSV) or Punta Toro virus Adames strain (PTA) were characterized previously. Although chimeric MP-12 strains are highly immunogenic, the attenuation through the S-segment remains unknown. Using pathogenic ZH501 strain, we aimed to demonstrate the attenuation of ZH501 strain through chimeric S-segment encoding either the NSs of TOSV, SFSV, PTA, or Punta Toro virus Balliet strain (PTB). In addition, we characterized rZH501 encoding a human dominant-negative PKR (PKRΔE7), which also enhances the immunogenicity of MP-12. Study done on mice revealed that attenuation of rZH501 occurred through the S-segment encoding either PKRΔE7 or SFSV NSs. However, rZH501 encoding either TOSV, PTA, or PTB NSs in the S-segment uniformly caused lethal encephalitis. Our results indicated that the S-segments encoding PKRΔE7 or SFSV NSs are attenuated and thus applicable toward next generation MP-12 vaccine candidates that encode a DIVA marker.

  13. Isolation of lactic acid bacteria from swine milk and characterization of potential probiotic strains with antagonistic effects against swine-associated gastrointestinal pathogens.

    Science.gov (United States)

    Quilodrán-Vega, Sandra Rayén; Villena, Julio; Valdebenito, José; Salas, María José; Parra, Cristian; Ruiz, Alvaro; Kitazawa, Haruki; García, Apolinaria

    2016-06-01

    Probiotics are usually isolated from the gastrointestinal tract of humans and animals. The search of probiotics in human milk is a recent field of research, as the existence of the human milk microbiome was discovered only about a decade ago. To our knowledge, no reports regarding the potential probiotic effect of bacteria from swine milk have been published. In this work, we isolated several lactic acid bacteria from swine milk and evaluated them for them potential as probiotics. Among the isolated strains, Lactobacillus curvatus TUCO-5E showed antagonistic effects against swine-associated gastrointestinal pathogens. TUCO-5E was able to reduce the growth of enterotoxigenic and enterohemorrhagic Escherichia coli strains as well as pathogenic salmonella. In vitro exclusion and displacement assays in intestinal epithelial cells showed a remarkable antagonistic effect for L. curvatus TUCO-5E against Salmonella sp. strain TUCO-I7 and Salmonella enterica ATCC 13096. Moreover, by using a mouse model of Salmonella infection, we were able to demonstrate that preventative administration of L. curvatus TUCO-5E for 5 consecutive days was capable of decreasing the number of Salmonella enterica serovar Typhimurium in the liver and spleen of treated mice, compared with the controls, and prevented dissemination of the pathogen to the blood stream. Therefore, we have demonstrated here that swine milk is an interesting source of beneficial bacteria. In addition, the results of this work suggest that L. curvatus TUCO-5E is a good candidate to study in vivo the protective effect of probiotics against intestinal infection and damage induced by Salmonella infection in the porcine host.

  14. Isolation of an H5N8 Highly Pathogenic Avian Influenza Virus Strain from Wild Birds in Seoul, a Highly Urbanized Area in South Korea.

    Science.gov (United States)

    Kwon, Jung-Hoon; Lee, Dong-Hun; Jeong, Jei-Hyun; Yuk, Seong-Su; Erdene-Ochir, Tseren-Ochir; Noh, Jin-Yong; Hong, Woo-Tack; Jeong, Sol; Gwon, Gyeong-Bin; Lee, Sang-Won; Choi, In-Soo; Song, Chang-Seon

    2017-07-01

    Asian-lineage H5 highly pathogenic avian influenza viruses (HPAIV) have caused recurrent outbreaks in poultry and wild birds. In January 2014, H5N8 HPAIV caused outbreaks in South Korea and subsequently spread to East Asia, Europe, and North America. We report the isolation of an H5N8 HPAIV strain from wild birds in Seoul, the most-developed city in South Korea. We analyzed the complete genome sequence of this isolate and estimated its origin using a phylogenetic analysis. The Seoul H5N8 isolate clustered phylogenetically with strains isolated from migratory wild birds but was distinct from Korean poultry isolates. This H5N8 virus was likely introduced into the urbanized city by migratory wild birds. Therefore, wild bird habitats in urbanized areas should be carefully monitored for HPAIV.

  15. The efficacy of different anti-microbial metals at preventing the formation of, and eradicating bacterial biofilms of pathogenic indicator strains.

    Science.gov (United States)

    Gugala, Natalie; Lemire, Joe A; Turner, Raymond J

    2017-06-01

    The emergence of multidrug-resistant pathogens and the prevalence of biofilm-related infections have generated a demand for alternative anti-microbial therapies. Metals have not been explored in adequate detail for their capacity to combat infectious disease. Metal compounds can now be found in textiles, medical devices and disinfectants-yet, we know little about their efficacy against specific pathogens. To help fill this knowledge gap, we report on the anti-microbial and antibiofilm activity of seven metals: silver, copper, titanium, gallium, nickel, aluminum and zinc against three bacterial strains, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. To evaluate the capacity of metal ions to prevent the growth of, and eradicate biofilms and planktonic cells, bacterial cultures were inoculated in the Calgary Biofilm Device (minimal biofilm eradication concentration) in the presence of the metal salts. Copper, gallium and titanium were capable of preventing planktonic and biofilm growth, and eradicating established biofilms of all tested strains. Further, we observed that the efficacies of the other tested metal salts displayed variable efficacy against the tested strains. Further, contrary to the enhanced resistance anticipated from bacterial biofilms, particular metal salts were observed to be more effective against biofilm communities versus planktonic cells. In this study, we have demonstrated that the identity of the bacterial strain must be considered before treatment with a particular metal ion. Consequent to the use of metal ions as anti-microbial agents to fight multidrug-resistant and biofilm-related infections increases, we must aim for more selective deployment in a given infectious setting.

  16. Prevalence and pathogenicity of binary toxin–positive Clostridium difficile strains that do not produce toxins A and B

    Directory of Open Access Journals (Sweden)

    C. Eckert

    2015-01-01

    Full Text Available Clostridium difficile causes antibiotic-associated diarrhoea and pseudomembranous colitis. The main virulence factors of C. difficile are the toxins A (TcdA and B (TcdB. A third toxin, called binary toxin (CDT, can be detected in 17% to 23% of strains, but its role in human disease has not been clearly defined. We report six independent cases of patients with diarrhoea suspected of having C. difficile infection due to strains from toxinotype XI/PCR ribotype 033 or 033-like, an unusual toxinotype/PCR ribotype positive for CDT but negative for TcdA and TcdB. Four patients were considered truly infected by clinicians and were specifically treated with oral metronidazole. One of the cases was identified during a prevalence study of A−B−CDT+ strains. In this study, we screened a French collection of 220 nontoxigenic strains and found only one (0.5% toxinotype XI/PCR ribotype 033 or 033-like strain. The description of such strains raises the question of the role of binary toxin as a virulence factor and could have implications for laboratory diagnostics that currently rarely include testing for binary toxin.

  17. Comparative genomics using microarrays reveals divergence and loss of virulence-associated genes in host-specific strains of the insect pathogen Metarhizium anisopliae.

    Science.gov (United States)

    Wang, Sibao; Leclerque, Andreas; Pava-Ripoll, Monica; Fang, Weiguo; St Leger, Raymond J

    2009-06-01

    Many strains of Metarhizium anisopliae have broad host ranges, but others are specialists and adapted to particular hosts. Patterns of gene duplication, divergence, and deletion in three generalist and three specialist strains were investigated by heterologous hybridization of genomic DNA to genes from the generalist strain Ma2575. As expected, major life processes are highly conserved, presumably due to purifying selection. However, up to 7% of Ma2575 genes were highly divergent or absent in specialist strains. Many of these sequences are conserved in other fungal species, suggesting that there has been rapid evolution and loss in specialist Metarhizium genomes. Some poorly hybridizing genes in specialists were functionally coordinated, indicative of reductive evolution. These included several involved in toxin biosynthesis and sugar metabolism in root exudates, suggesting that specialists are losing genes required to live in alternative hosts or as saprophytes. Several components of mobile genetic elements were also highly divergent or lost in specialists. Exceptionally, the genome of the specialist cricket pathogen Ma443 contained extra insertion elements that might play a role in generating evolutionary novelty. This study throws light on the abundance of orphans in genomes, as 15% of orphan sequences were found to be rapidly evolving in the Ma2575 lineage.

  18. Complete Genome Sequence of Streptococcus thermophilus KLDS 3.1003, A Strain with High Antimicrobial Potential against Foodborne and Vaginal Pathogens

    Directory of Open Access Journals (Sweden)

    Smith E. Evivie

    2017-07-01

    Full Text Available Lactic acid bacteria play increasingly important roles in the food industry. Streptococcus thermophilus KLDS 3.1003 strain was isolated from traditional yogurt in Inner Mongolia, China. It has shown high antimicrobial activity against selected foodborne and vaginal pathogens. In this study, we investigated and analyzed its complete genome sequence. The S. thermophilus KLDS 3.1003 genome comprise of a 1,899,956 bp chromosome with a G+C content of 38.92%, 1,995 genes, and 6 rRNAs. With the exception of S. thermophilus M17TZA496, S. thermophilus KLDS 3.1003 has more tRNAs (amino acid coding genes compared to some S. thermophilus strains available on the National Centre for Biotechnology Information database. MG-RAST annotation showed that this strain has 317 subsystems with most genes associated with amino acid and carbohydrate metabolism. This strain also has a unique EPS gene cluster containing 23 genes, and may be a mixed dairy starter culture. This information provides more insight into the molecular basis of its potentials for further applications in the dairy and allied industries.

  19. Probiotic potential of Lactobacilli with antagonistic activity against pathogenic strains: An in vitro validation for the production of inhibitory substances

    Directory of Open Access Journals (Sweden)

    Chidre Prabhurajeshwar

    2017-10-01

    Conclusion: Based on the drawn results, T2, T4 and T16 Lactobacillus isolates were recognised as ideal, potential in vitro antimicrobial probiotic isolates against pathogens and studies are needed further in-vivo assessment and human health benefits in their real-life situations.

  20. Removal of two waterborne pathogenic bacterial strains by activated carbon particles prior to and after charge modification

    NARCIS (Netherlands)

    Busscher, Henk J.; Dijkstra, Rene J. B.; Engels, Eefje; Langworthy, Don E.; Collias, Dimitris I.; Bjorkquist, David W.; Mitchell, Michael D.; van der Mei, Henny C.

    2006-01-01

    Waterborne diseases constitute a threat to public health despite costly treatment measures aimed at removing pathogenic microorganisms from potable water supplies. This paper compared the removal of Raoultella terrigena ATCC 33257 and Escherichia coli ATCC 25922 by negatively and positively charged

  1. Multiple advanced logic gates made of DNA-Ag nanocluster and the application for intelligent detection of pathogenic bacterial genes.

    Science.gov (United States)

    Lin, Xiaodong; Liu, Yaqing; Deng, Jiankang; Lyu, Yanlong; Qian, Pengcheng; Li, Yunfei; Wang, Shuo

    2018-02-21

    The integration of multiple DNA logic gates on a universal platform to implement advance logic functions is a critical challenge for DNA computing. Herein, a straightforward and powerful strategy in which a guanine-rich DNA sequence lighting up a silver nanocluster and fluorophore was developed to construct a library of logic gates on a simple DNA-templated silver nanoclusters (DNA-AgNCs) platform. This library included basic logic gates, YES, AND, OR, INHIBIT, and XOR, which were further integrated into complex logic circuits to implement diverse advanced arithmetic/non-arithmetic functions including half-adder, half-subtractor, multiplexer, and demultiplexer. Under UV irradiation, all the logic functions could be instantly visualized, confirming an excellent repeatability. The logic operations were entirely based on DNA hybridization in an enzyme-free and label-free condition, avoiding waste accumulation and reducing cost consumption. Interestingly, a DNA-AgNCs-based multiplexer was, for the first time, used as an intelligent biosensor to identify pathogenic genes, E. coli and S. aureus genes, with a high sensitivity. The investigation provides a prototype for the wireless integration of multiple devices on even the simplest single-strand DNA platform to perform diverse complex functions in a straightforward and cost-effective way.

  2. Complete Genome Sequence of Yersinis pestis Strains Antiqua and Nepa1516: Evidence of Gene Reduction in an Emerging Pathogen

    Energy Technology Data Exchange (ETDEWEB)

    Chain, Patrick S [ORNL; Hu, Ping [Lawrence Berkeley National Laboratory (LBNL); Malfatti, Stephanie [Lawrence Livermore National Laboratory (LLNL); Radnedge, Lyndsay [Lawrence Livermore National Laboratory (LLNL); Larimer, Frank W [ORNL; Vergez, Lisa [Lawrence Livermore National Laboratory (LLNL); Worsham, Patricia [U.S. Army Medical Research Institute of Infectious Diseases; Chu, May C [Centers for Disease Control and Prevention; Anderson, Gary L [Lawrence Berkeley National Laboratory (LBNL)

    2006-01-01

    Yersinia pestis, the causative agent of bubonic and pneumonic plagues, has undergone detailed study at the molecular level. To further investigate the genomic diversity among this group and to help characterize lineages of the plague organism that have no sequenced members, we present here the genomes of two isolates of the ''classical'' antiqua biovar, strains Antiqua and Nepal516. The genomes of Antiqua and Nepal516 are 4.7 Mb and 4.5 Mb and encode 4,138 and 3,956 open reading frames, respectively. Though both strains belong to one of the three classical biovars, they represent separate lineages defined by recent phylogenetic studies. We compare all five currently sequenced Y. pestis genomes and the corresponding features in Yersinia pseudotuberculosis. There are strain-specific rearrangements, insertions, deletions, single nucleotide polymorphisms, and a unique distribution of insertion sequences. We found 453 single nucleotide polymorphisms in protein-coding regions, which were used to assess the evolutionary relationships of these Y. pestis strains. Gene reduction analysis revealed that the gene deletion processes are under selective pressure, and many of the inactivations are probably related to the organism's interaction with its host environment. The results presented here clearly demonstrate the differences between the two biovar antiqua lineages and support the notion that grouping Y. pestis strains based strictly on the classical definition of biovars (predicated upon two biochemical assays) does not accurately reflect the phylogenetic relationships within this species. A comparison of four virulent Y. pestis strains with the human-avirulent strain 91001 provides further insight into the genetic basis of virulence to humans.

  3. Proof of Principle for a Real-Time Pathogen Isolation Media Diagnostic: The Use of Laser-Induced Breakdown Spectroscopy to Discriminate Bacterial Pathogens and Antimicrobial-Resistant Staphylococcus aureus Strains Grown on Blood Agar

    Directory of Open Access Journals (Sweden)

    Rosalie A. Multari

    2013-01-01

    Full Text Available Laser-Induced Breakdown Spectroscopy (LIBS is a rapid, in situ, diagnostic technique in which light emissions from a laser plasma formed on the sample are used for analysis allowing automated analysis results to be available in seconds to minutes. This speed of analysis coupled with little or no sample preparation makes LIBS an attractive detection tool. In this study, it is demonstrated that LIBS can be utilized to discriminate both the bacterial species and strains of bacterial colonies grown on blood agar. A discrimination algorithm was created based on multivariate regression analysis of spectral data. The algorithm was deployed on a simulated LIBS instrument system to demonstrate discrimination capability using 6 species. Genetically altered Staphylococcus aureus strains grown on BA, including isogenic sets that differed only by the acquisition of mutations that increase fusidic acid or vancomycin resistance, were also discriminated. The algorithm successfully identified all thirteen cultures used in this study in a time period of 2 minutes. This work provides proof of principle for a LIBS instrumentation system that could be developed for the rapid discrimination of bacterial species and strains demonstrating relatively minor genomic alterations using data collected directly from pathogen isolation media.

  4. Isolation and characterization of numerous novel phages targeting diverse strains of the ubiquitous and opportunistic pathogen Achromobacter xylosoxidans.

    Directory of Open Access Journals (Sweden)

    Johannes Wittmann

    Full Text Available The clinical relevance of nosocomially acquired infections caused by multi-resistant Achromobacter strains is rapidly increasing. Here, a diverse set of 61 Achromobacter xylosoxidans strains was characterized by MultiLocus Sequence Typing and Phenotype MicroArray technology. The strains were further analyzed in regard to their susceptibility to 35 antibiotics and to 34 different and newly isolated bacteriophages from the environment. A large proportion of strains were resistant against numerous antibiotics such as cephalosporines, aminoglycosides and quinolones, whereas piperacillin-tazobactam, ticarcillin, mezlocillin and imipenem were still inhibitory. We also present the first expanded study on bacteriophages of the genus Achromobacter that has been so far a blank slate with respect to phage research. The phages were isolated mainly from several waste water treatment plants in Germany. Morphological analysis of all of these phages by electron microscopy revealed a broad diversity with different members of the order Caudovirales, including the families Siphoviridae, Myoviridae, and Podoviridae. A broad spectrum of different host ranges could be determined for several phages that lysed up to 24 different and in part highly antibiotic resistant strains. Molecular characterisation by DNA restriction analysis revealed that all phages contain linear double-stranded DNA. Their restriction patterns display distinct differences underlining their broad diversity.

  5. Complete Genome Sequence of Yersinia pestis Strains Antiqua andNepal516: Evidence of Gene Reduction in an Emerging Pathogen

    Energy Technology Data Exchange (ETDEWEB)

    Chain, Patrick S.G.; Hu, Ping; Malfatti, Stephanie A.; Radnedge,Lyndsay; Larimer, Frank; Vergez, Lisa M.; Worsham, Patricia; Chu, May C.; Andersen, Gary L.

    2006-01-16

    Yersinia pestis, the causative agent of bubonic andpneumonicplague, has undergone detailed study at the molecular level. Tofurther investigate the genomic diversity among this group and to helpcharacterize lineages of the plague organism that have no sequencedmembers, we present here the genomes of two isolates of the "classical"Antiqua biovar, strains Antiqua and Nepal516. The genomes of Antiqua andNepal516 are 4.7 Mb and 4.5 Mb and encode 4,138 and 3,956 open readingframes respectively. Though both strains belong to one of the threeclassical biovars, they represent separate lineages defined by recentphylogenetic studies. We compare all five currently sequenced Y. pestisgenomes and the corresponding features in Y. pseudotuberculosis. Thereare strain-specific rearrangements, insertions, deletions, singlenucleotide polymorphisms and a unique distribution of insertionsequences. We found 453 single nucleotide polymorphisms in protein codingregions, which were used to assess evolutionary relationships of these Y.pestis strains. Gene reduction analysis revealed that the gene deletionprocesses are under selective pressure and many of the inactivations areprobably related to the organism s interaction with its host environment.The results presented here clearly demonstrate the differences betweenthe two Antiqua lineages and support the notion that grouping Y. pestisstrains based strictly on the classical definition of biovars (predicatedupon two biochemical assays) does not accurately reflect the phylogeneticrelationships within this species. Comparison of four virulent Y. pestisstrains with the human-avirulent strain 91001 provides further insightinto the genetic basis of virulence to humans.

  6. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the period 7/1/00 to 10/30/00

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paul Keim

    2000-11-07

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens.

  7. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the period 7/1/00 to 10/30/00

    International Nuclear Information System (INIS)

    Dr. Paul Keim

    2000-01-01

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens

  8. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the Period 4/1/00 to 6/30/00

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paul Keim

    2000-11-07

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens.

  9. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the Period 4/1/00 to 6/30/00

    International Nuclear Information System (INIS)

    Dr. Paul Keim

    2000-01-01

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens

  10. New insights into virulence mechanisms of rice pathogen Acidovorax avenae subsp. avenae strain RS-1 following exposure to ß-lactam antibiotics.

    Science.gov (United States)

    Li, Bin; Ge, Mengyu; Zhang, Yang; Wang, Li; Ibrahim, Muhammad; Wang, Yanli; Sun, Guochang; Chen, Gongyou

    2016-02-26

    Recent research has shown that pathogen virulence can be altered by exposure to antibiotics, even when the growth rate is unaffected. Investigating this phenomenon provides new insights into understanding the virulence mechanisms of bacterial pathogens. This study investigates the phenotypic and transcriptomic responses of the rice pathogenic bacterium Acidovorax avenae subsp. avenae (Aaa) strain RS-1 to ß-lactam antibiotics especially Ampicillin (Amp). Our results indicate that exposure to Amp does not influence bacterial growth and biofilm formation, but alters the virulence, colonization capacity, composition of extracellular polymeric substances and secretion of Type VI secretion system (T6SS) effector Hcp. This attenuation in virulence is linked to unique or differential expression of known virulence-associated genes based on genome-wide transcriptomic analysis. The reliability of expression data generated by RNA-Seq was verified with quantitative real-time PCR of 21 selected T6SS genes, where significant down-regulation in expression of hcp gene, corresponding to the reduction in secretion of Hcp, was observed under exposure to Amp. Hcp is highlighted as a potential target for Amp, with similar changes observed in virulence-associated phenotypes between exposure to Amp and mutation of hcp gene. In addition, Hcp secretion is reduced in knockout mutants of 4 differentially expressed T6SS genes.

  11. Comparing Avocado, Swamp Bay, and Camphortree as Hosts of Raffaelea lauricola Using a Green Fluorescent Protein (GFP)-Labeled Strain of the Pathogen.

    Science.gov (United States)

    Campbell, A S; Ploetz, R C; Rollins, J A

    2017-01-01

    Raffaelea lauricola, a fungal symbiont of the ambrosia beetle Xyleborus glabratus, causes laurel wilt in members of the Lauraceae plant family. North American species in the family, such as avocado (Persea americana) and swamp bay (P. palustris), are particularly susceptible to laurel wilt, whereas the Asian camphortree (Cinnamomum camphora) is relatively tolerant. To determine whether susceptibility is related to pathogen colonization, a green fluorescent protein-labeled strain of R. lauricola was generated and used to inoculate avocado, swamp bay, and camphortree. Trees were harvested 3, 10, and 30 days after inoculation (DAI), and disease severity was rated on a 1-to-10 scale. By 30 DAI, avocado and swamp bay developed significantly more severe disease than camphortree (mean severities of 6.8 and 5.5 versus 1.6, P < 0.003). The extent of xylem colonization was recorded as the percentage of lumena that were colonized by the pathogen. More xylem was colonized in avocado than camphortree (0.9% versus 0.1%, P < 0.03) but colonization in swamp bay (0.4%) did not differ significantly from either host. Although there were significant correlations between xylem colonization and laurel wilt severity in avocado (r = 0.74), swamp bay (r = 0.82), and camphortree (r = 0.87), even severely affected trees of all species were scarcely colonized by the pathogen.

  12. A putative marker for human pathogenic strains of Anaplasma phagocytophilum correlates with geography and host, but not human tropism.

    Science.gov (United States)

    Foley, Janet; Stephenson, Nicole; Cubilla, Michelle Pires; Qurollo, Barbara; Breitschwerdt, Edward B

    2016-03-01

    Anaplasma phagocytophilum is an Ixodes species tick-transmitted bacterium that is capable of infecting a variety of host species, although there is a diversity of bacterial strains with differing host tropism. Recent analysis of A. phagocytophilum strains suggested that "drhm", a gene locus designated "distantly related to human marker" (drhm), which was predicted to be an integral membrane protein with possible transporter functions was not present in available canine and human isolates. By assessing 117 strains from 14 host species from across the US, we extended this analysis. Phylogenetic clades were associated with geography, but not host species. Additionally, a virulent clade that lacks drhm and infects dogs, horses, and humans in northeastern US was identified. Copyright © 2015 Elsevier GmbH. All rights reserved.

  13. Pathogenic potential of a Costa Rican strain of 'Candidatus Rickettsia amblyommii' in guinea pigs (Cavia porcellus) and protective immunity against Rickettsia rickettsii.

    Science.gov (United States)

    Rivas, Juan J; Moreira-Soto, Andrés; Alvarado, Gilberth; Taylor, Lizeth; Calderón-Arguedas, Olger; Hun, Laya; Corrales-Aguilar, Eugenia; Morales, Juan Alberto; Troyo, Adriana

    2015-09-01

    'Candidatus Rickettsia amblyommii' is a spotted fever group rickettsia that is not considered pathogenic, although there is serologic evidence of possible infection in animals and humans. The aim of this study was to evaluate the pathogenic potential of a Costa Rican strain of 'Candidatus R. amblyommii' in guinea pigs and determine its capacity to generate protective immunity against a subsequent infection with a local strain of Rickettsia rickettsii isolated from a human case. Six guinea pigs were inoculated with 'Candidatus R. amblyommii' strain 9-CC-3-1 and two controls with cell culture medium. Health status was evaluated, and necropsies were executed at days 2, 4, and 13. Blood and tissues were processed by PCR to detect the gltA gene, and end titers of anti-'Candidatus R. amblyommii' IgG were determined by indirect immunofluorescence. To evaluate protective immunity, another 5 guinea pigs were infected with 'Candidatus R. amblyommii' (IGPs). After 4 weeks, these 5 IGPs and 3 controls (CGPs) were inoculated with pathogenic R. rickettsii. Clinical signs and titers of anti-Rickettsia IgG were determined. IgG titers reached 1:512 at day 13 post-infection with 'Candidatus R. amblyommii'. On day 2 after inoculation, two guinea pigs had enlarged testicles and 'Candidatus R. amblyommii' DNA was detected in testicles. Histopathology confirmed piogranulomatous orchitis with perivascular inflammatory infiltrate in the epididymis. In the protective immunity assay, anti-Rickettsia IgG end titers after R. rickettsii infection were lower in IGPs than in CGPs. IGPs exhibited only transient fever, while CGP showed signs of severe disease and mortality. R. rickettsii was detected in testicles and blood of CGPs. Results show that the strain 9-CC-3-1 of 'Candidatus R. amblyommii' was able to generate pathology and an antibody response in guinea pigs. Moreover, its capacity to generate protective immunity against R. rickettsii may modulate the epidemiology and severity of Rocky

  14. Genome sequence of Ochrobactrum anthropi strain SUBG007, a plant pathogen and potential xenobiotic compounds degradation bacterium

    Directory of Open Access Journals (Sweden)

    Kiran S. Chudasama

    2017-03-01

    Full Text Available Ochrobactrum anthropi SUBG007 was isolated from the fruit of Prunus dulcis in Rajkot (22.30°N, 70.78°E, Gujarat, India. Here we present the 4.37 Mb genome sequence strain SUBG007, which may provide the genetic information for the application in environment pollution degradation and agriculture field. The strain also posses many genes cluster which involved in production of important secondary metabolites. The nucleotide sequence of this genome was deposited into NCBI GenBank under the accession LUAY00000000.

  15. Complete genome sequence of Bacillus velezensis G341, a strain with a broad inhibitory spectrum against plant pathogens.

    Science.gov (United States)

    Lee, Hyun-Hee; Park, Jungwook; Lim, Jae Yun; Kim, Hun; Choi, Gyung Ja; Kim, Jin-Cheol; Seo, Young-Su

    2015-10-10

    Bacillus velezensis G341 can suppress plant pathogens by producing antagonistic active compounds including bacillomycin D, fengycin, and (oxy) difficidin. The complete genome sequence of this bacterium was characterized by one circular chromosome of 4,009,746bp with 3953 open reading frames. The genome contained 36 pseudogenes, 30 rRNA operons, and 95 tRNAs. This complete genome sequence provides an additional resource for the development of antimicrobial compounds. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Genetic analysis of environmental strains of the plant pathogen Phytophthora capsici reveals heterogeneous repertoire of effectors and possible effector evolution via genomic island.

    Science.gov (United States)

    Iribarren, María Josefina; Pascuan, Cecilia; Soto, Gabriela; Ayub, Nicolás Daniel

    2015-11-01

    Phytophthora capsici is a virulent oomycete pathogen of many vegetable crops. Recently, it has been demonstrated that the recognition of the RXLR effector AVR3a1 of P. capsici (PcAVR3a1) triggers a hypersensitive response and plays a critical role in mediating non-host resistance. Here, we analyzed the occurrence of PcAVR3a1 in 57 isolates of P. capsici derived from globe squash, eggplant, tomato and bell pepper cocultivated in a small geographical area. The occurrence of PcAVR3a1 in environmental strains of P. capsici was confirmed by PCR in only 21 of these pathogen isolates. To understand the presence-absence pattern of PcAVR3a1 in environmental strains, the flanking region of this gene was sequenced. PcAVR3a1 was found within a genetic element that we named PcAVR3a1-GI (PcAVR3a1 genomic island). PcAVR3a1-GI was flanked by a 22-bp direct repeat, which is related to its site-specific recombination site. In addition to the PcAVR3a1 gene, PcAVR3a1-GI also encoded a phage integrase probably associated with the excision and integration of this mobile element. Exposure to plant induced the presence of an episomal circular intermediate of PcAVR3a1-GI, indicating that this mobile element is functional. Collectively, these findings provide evidence of PcAVR3a1 evolution via mobile elements in environmental strains of Phytophthora. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Pathogenicity of fumonisin-producing and nonproducing strains of Aspergillus species in section Nigri to maize ears and seedlings

    Science.gov (United States)

    Species of Aspergillus section Nigri are commonly associated with maize kernels, and some strains can produce fumonisin mycotoxins. However, there is little information about the extent to which these fungi contribute to fumonisin contamination in grain, the damage they cause to maize ears, or their...

  18. Evaluation and Comparison of the Pathogenicity and Host Immune Responses Induced by a G2b Taiwan Porcine Epidemic Diarrhea Virus (Strain Pintung 52) and Its Highly Cell-Culture Passaged Strain in Conventional 5-Week-Old Pigs.

    Science.gov (United States)

    Chang, Yen-Chen; Kao, Chi-Fei; Chang, Chia-Yu; Jeng, Chian-Ren; Tsai, Pei-Shiue; Pang, Victor Fei; Chiou, Hue-Ying; Peng, Ju-Yi; Cheng, Ivan-Chen; Chang, Hui-Wen

    2017-05-19

    A genogroup 2b (G2b) porcine epidemic diarrhea virus (PEDV) Taiwan Pintung 52 (PEDVPT) strain was isolated in 2014. The pathogenicity and host antibody responses elicited by low-passage (passage 5; PEDVPT-P5) and high-passage (passage 96; PEDVPT-P96) PEDVPT strains were compared in post-weaning PEDV-seronegative pigs by oral inoculation. PEDVPT-P5-inoculation induced typical diarrhea during 1-9 days post inoculation with fecal viral shedding persisting for 26 days. Compared to PEDVPT-P5, PEDVPT-P96 inoculation induced none-to-mild diarrhea and lower, delayed fecal viral shedding. Although PEDVPT-P96 elicited slightly lower neutralizing antibodies and PEDV-specific immunoglobulin G (IgG) and immunoglobulin A (IgA) titers, a reduction in pathogenicity and viral shedding of the subsequent challenge with PEDVPT-P5 were noted in both PEDVPT-P5- and PEDVPT-P96-inoculated pigs. Alignment and comparison of full-length sequences of PEDVPT-P5 and PEDVPT-P96 revealed 23 nucleotide changes and resultant 19 amino acid substitutions in non-structure proteins 2, 3, 4, 9, 14, 15, spike, open reading frame 3 (ORF3), and membrane proteins with no detectable deletion or insertion. The present study confirmed the pathogenicity of the PEDVPT isolate in conventional post-weaning pigs. Moreover, data regarding viral attenuation and potency of induced antibodies against PEDVPT-P5 identified PEDVPT-P96 as a potential live-attenuated vaccine candidate.

  19. Genetic affinities within a large global collection of pathogenic Leptospira: implications for strain identification and molecular epidemiology.

    Directory of Open Access Journals (Sweden)

    Kishore Nalam

    Full Text Available Leptospirosis is an important zoonosis with widespread human health implications. The non-availability of accurate identification methods for the individualization of different Leptospira for outbreak investigations poses bountiful problems in the disease control arena. We harnessed fluorescent amplified fragment length polymorphism analysis (FAFLP for Leptospira and investigated its utility in establishing genetic relationships among 271 isolates in the context of species level assignments of our global collection of isolates and strains obtained from a diverse array of hosts. In addition, this method was compared to an in-house multilocus sequence typing (MLST method based on polymorphisms in three housekeeping genes, the rrs locus and two envelope proteins. Phylogenetic relationships were deduced based on bifurcating Neighbor-joining trees as well as median joining network analyses integrating both the FAFLP data and MLST based haplotypes. The phylogenetic relationships were also reproduced through Bayesian analysis of the multilocus sequence polymorphisms. We found FAFLP to be an important method for outbreak investigation and for clustering of isolates based on their geographical descent rather than by genome species types. The FAFLP method was, however, not able to convey much taxonomical utility sufficient to replace the highly tedious serotyping procedures in vogue. MLST, on the other hand, was found to be highly robust and efficient in identifying ancestral relationships and segregating the outbreak associated strains or otherwise according to their genome species status and, therefore, could unambiguously be applied for investigating phylogenetics of Leptospira in the context of taxonomy as well as gene flow. For instance, MLST was more efficient, as compared to FAFLP method, in clustering strains from the Andaman island of India, with their counterparts from mainland India and Sri Lanka, implying that such strains share genetic

  20. Identification of human-pathogenic strains of Shiga toxin-producing Escherichia coli from food by a combination of serotyping and molecular typing of Shiga toxin genes.

    Science.gov (United States)

    Beutin, Lothar; Miko, Angelika; Krause, Gladys; Pries, Karin; Haby, Sabine; Steege, Katja; Albrecht, Nadine

    2007-08-01

    We examined 219 Shiga toxin-producing Escherichia coli (STEC) strains from meat, milk, and cheese samples collected in Germany between 2005 and 2006. All strains were investigated for their serotypes and for genetic variants of Shiga toxins 1 and 2 (Stx1 and Stx2). stx(1) or variant genes were detected in 88 (40.2%) strains and stx(2) and variants in 177 (80.8%) strains. Typing of stx genes was performed by stx-specific PCRs and by analysis of restriction fragment length polymorphisms (RFLP) of PCR products. Major genotypes of the Stx1 (stx(1), stx(1c), and stx(1d)) and the Stx2 (stx(2), stx(2d), stx(2-O118), stx(2e), and stx(2g)) families were detected, and multiple types of stx genes coexisted frequently in STEC strains. Only 1.8% of the STEC strains from food belonged to the classical enterohemorrhagic E. coli (EHEC) types O26:H11, O103:H2, and O157:H7, and only 5.0% of the STEC strains from food were positive for the eae gene, which is a virulence trait of classical EHEC. In contrast, 95 (43.4%) of the food-borne STEC strains carried stx(2) and/or mucus-activatable stx(2d) genes, an indicator for potential high virulence of STEC for humans. Most of these strains belonged to serotypes associated with severe illness in humans, such as O22:H8, O91:H21, O113:H21, O174:H2, and O174:H21. stx(2) and stx(2d) STEC strains were found frequently in milk and beef products. Other stx types were associated more frequently with pork (stx(2e)), lamb, and wildlife meat (stx(1c)). The combination of serotyping and stx genotyping was found useful for identification and for assignment of food-borne STEC to groups with potential lower and higher levels of virulence for humans.

  1. Seminal fluid of honeybees contains multiple mechanisms to combat infections of the sexually transmitted pathogen Nosema apis.

    Science.gov (United States)

    Peng, Yan; Grassl, Julia; Millar, A Harvey; Baer, Boris

    2016-01-27

    The societies of ants, bees and wasps are genetically closed systems where queens only mate during a brief mating episode prior to their eusocial life and males therefore provide queens with a lifetime supply of high-quality sperm. These ejaculates also contain a number of defence proteins that have been detected in the seminal fluid but their function and efficiency have never been investigated in great detail. Here, we used the honeybee Apis mellifera and quantified whether seminal fluid is able to combat infections of the fungal pathogen Nosema apis, a widespread honeybee parasite that is also sexually transmitted. We provide the first empirical evidence that seminal fluid has a remarkable antimicrobial activity against N. apis spores and that antimicrobial seminal fluid components kill spores in multiple ways. The protein fraction of seminal fluid induces extracellular spore germination, which disrupts the life cycle of N. apis, whereas the non-protein fraction of seminal fluid induces a direct viability loss of intact spores. We conclude that males provide their ejaculates with efficient antimicrobial molecules that are able to kill N. apis spores and thereby reduce the risk of disease transmission during mating. Our findings could be of broader significance to master honeybee diseases in managed honeybee stock in the future. © 2016 The Author(s).

  2. The Gene tia, Harbored by the Subtilase-Encoding Pathogenicity Island, Is Involved in the Ability of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli Strains To Invade Monolayers of Epithelial Cells

    Science.gov (United States)

    Chiani, Paola; Michelacci, Valeria; Minelli, Fabio; Caprioli, Alfredo; Morabito, Stefano

    2017-01-01

    ABSTRACT Locus of enterocyte effacement (LEE)-negative Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC strains to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia, previously described in enterotoxigenic E. coli strains, has been identified in LEE-negative STEC strains that possess the subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia, present in these LEE-negative STEC strains, in the invasion of monolayers of cultured cells. We observed that these strains were able to invade Caco-2 and HEp-2 cell monolayers and compared their invasion ability with that of a mutant strain in which the gene tia had been inactivated. Mutation of the gene tia resulted in a strong reduction of the invasive phenotype, and complementation of the tia mutation with a functional copy of the gene restored the invasion activity. Moreover, we show that the gene tia is overexpressed in bacteria actively invading cell monolayers, demonstrating that tia is involved in the ability to invade cultured monolayers of epithelial cells shown by SE-PAI-positive E. coli, including STEC, strains. However, the expression of the tia gene in the E. coli K-12 strain JM109 was not sufficient, in its own right, to confer to this strain the ability to invade cell monolayers, suggesting that at least another factor must be involved in the invasion ability displayed by the SE-PAI-positive strains. PMID:28893912

  3. The Gene tia, Harbored by the Subtilase-Encoding Pathogenicity Island, Is Involved in the Ability of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli Strains To Invade Monolayers of Epithelial Cells.

    Science.gov (United States)

    Bondì, Roslen; Chiani, Paola; Michelacci, Valeria; Minelli, Fabio; Caprioli, Alfredo; Morabito, Stefano

    2017-12-01

    Locus of enterocyte effacement (LEE)-negative Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC strains to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia , previously described in enterotoxigenic E. coli strains, has been identified in LEE-negative STEC strains that possess the subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia , present in these LEE-negative STEC strains, in the invasion of monolayers of cultured cells. We observed that these strains were able to invade Caco-2 and HEp-2 cell monolayers and compared their invasion ability with that of a mutant strain in which the gene tia had been inactivated. Mutation of the gene tia resulted in a strong reduction of the invasive phenotype, and complementation of the tia mutation with a functional copy of the gene restored the invasion activity. Moreover, we show that the gene tia is overexpressed in bacteria actively invading cell monolayers, demonstrating that tia is involved in the ability to invade cultured monolayers of epithelial cells shown by SE-PAI-positive E. coli , including STEC, strains. However, the expression of the tia gene in the E. coli K-12 strain JM109 was not sufficient, in its own right, to confer to this strain the ability to invade cell monolayers, suggesting that at least another factor must be involved in the invasion ability displayed by the SE-PAI-positive strains. Copyright © 2017 American Society for Microbiology.

  4. Persistent environmental contamination with USA300 methicillin-resistant Staphylococcus aureus and other pathogenic strain types in households with S. aureus skin infections.

    Science.gov (United States)

    Eells, Samantha J; David, Michael Z; Taylor, Alexis; Ortiz, Nancy; Kumar, Neha; Sieth, Julia; Boyle-Vavra, Susan; Daum, Robert S; Miller, Loren G

    2014-11-01

    To understand the genotypic spectrum of environmental contamination of Staphylococcus aureus in households and its persistence. Prospective longitudinal cohort investigation. Index participants identified at 2 academic medical centers. Adults and children with S. aureus skin infections and their household contacts in Los Angeles and Chicago. Household fomites were surveyed for contamination at baseline and 3 months. All isolates underwent genetic typing. We enrolled 346 households, 88% of which completed the 3-month follow-up visit. S. aureus environmental contamination was 49% at baseline and 51% at 3 months. Among households with a USA300 methicillin-resistant S. aureus (MRSA) body infection isolate, environmental contamination with an indistinguishable MRSA strain was 58% at baseline and 63% at 3 months. Baseline factors associated with environmental contamination by the index subject's infection isolate were body colonization by any household member with the index subject's infection isolate at baseline (odds ratio [OR], 10.93 [95% confidence interval (CI), 5.75-20.79]), higher housing density (OR, 1.47 [95% CI, 1.10-1.96]), and more frequent household fomite cleaning (OR, 1.62 [95% CI, 1.16-2.27]). Household environmental contamination with the index subject's infection strain at 3 months was associated with USA300 MRSA and a synergistic interaction between baseline environmental contamination and body colonization by any household member with the index subject's infection strain. We found that infecting S. aureus isolates frequently persisted environmentally in households 3 months after skin infection. Presence of pathogenic S. aureus strain type in the environment in a household may represent a persistent reservoir that places household members at risk of future infection.

  5. Role of the Genes of Type VI Secretion System in Virulence of Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae Strain RS-2

    Directory of Open Access Journals (Sweden)

    Md. Mahidul Islam Masum

    2017-09-01

    Full Text Available The Type VI secretion system (T6SS is a class of macromolecular machine that is required for the virulence of gram-negative bacteria. However, it is still not clear what the role of T6SS in the virulence of rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa is. The aim of the current study was to investigate the contribution of T6SS in Aaa strain RS2 virulence using insertional deletion mutation and complementation approaches. This strain produced weak virulence but contains a complete T6SS gene cluster based on a genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type (RS-2 and 25 T6SS mutants, which were constructed using homologous recombination methods. The mutation of 15 T6SS genes significantly reduced bacterial virulence and the secretion of Hcp protein. Additionally, the complemented 7 mutations ΔpppA, ΔclpB, Δhcp, ΔdotU, ΔicmF, ΔimpJ, and ΔimpM caused similar virulence characteristics as RS-2. Moreover, the mutant ΔpppA, ΔclpB, ΔicmF, ΔimpJ and ΔimpM genes caused by a 38.3~56.4% reduction in biofilm formation while the mutants ΔpppA, ΔclpB, ΔicmF and Δhcp resulted in a 37.5~44.6% reduction in motility. All together, these results demonstrate that T6SS play vital roles in the virulence of strain RS-2, which may be partially attributed to the reductions in Hcp secretion, biofilm formation and motility. However, differences in virulence between strain RS-1 and RS-2 suggest that other factors may also be involved in the virulence of Aaa.

  6. Role of the Genes of Type VI Secretion System in Virulence of Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae Strain RS-2.

    Science.gov (United States)

    Masum, Md Mahidul Islam; Yang, Yingzi; Li, Bin; Olaitan, Ogunyemi Solabomi; Chen, Jie; Zhang, Yang; Fang, Yushi; Qiu, Wen; Wang, Yanli; Sun, Guochang

    2017-09-21

    The Type VI secretion system (T6SS) is a class of macromolecular machine that is required for the virulence of gram-negative bacteria. However, it is still not clear what the role of T6SS in the virulence of rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) is. The aim of the current study was to investigate the contribution of T6SS in Aaa strain RS2 virulence using insertional deletion mutation and complementation approaches. This strain produced weak virulence but contains a complete T6SS gene cluster based on a genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type (RS-2) and 25 T6SS mutants, which were constructed using homologous recombination methods. The mutation of 15 T6SS genes significantly reduced bacterial virulence and the secretion of Hcp protein. Additionally, the complemented 7 mutations Δ pppA , Δ clpB , Δ hcp , Δ dotU , Δ icmF , Δ impJ , and Δ impM caused similar virulence characteristics as RS-2. Moreover, the mutant Δ pppA , Δ clpB , Δ icmF , Δ impJ and Δ impM genes caused by a 38.3~56.4% reduction in biofilm formation while the mutants Δ pppA , Δ clpB , Δ icmF and Δ hcp resulted in a 37.5~44.6% reduction in motility. All together, these results demonstrate that T6SS play vital roles in the virulence of strain RS-2, which may be partially attributed to the reductions in Hcp secretion, biofilm formation and motility. However, differences in virulence between strain RS-1 and RS-2 suggest that other factors may also be involved in the virulence of Aaa.

  7. Combinatorial Strategies for Improving Multiple-Stress Resistance in Industrially Relevant Escherichia coli Strains

    DEFF Research Database (Denmark)

    Lennen, Rebecca; Herrgard, Markus

    2014-01-01

    High-cell-density fermentation for industrial production of chemicals can impose numerous stresses on cells due to high substrate, product, and by-product concentrations; high osmolarity; reactive oxygen species; and elevated temperatures. There is a need to develop platform strains of industrial...

  8. Whole genome sequence of the emerging oomycete pathogen Pythium insidiosum strain CDC-B5653 isolated from an infected human in the USA

    Directory of Open Access Journals (Sweden)

    Marina S. Ascunce

    2016-03-01

    Full Text Available Pythium insidiosum ATCC 200269 strain CDC-B5653, an isolate from necrotizing lesions on the mouth and eye of a 2-year-old boy in Memphis, Tennessee, USA, was sequenced using a combination of Illumina MiSeq (300 bp paired-end, 14 millions reads and PacBio (10  Kb fragment library, 356,001 reads. The sequencing data were assembled using SPAdes version 3.1.0, yielding a total genome size of 45.6 Mb contained in 8992 contigs, N50 of 13 Kb, 57% G + C content, and 17,867 putative protein-coding genes. This Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession JRHR00000000. Keywords: Oomycete, Pythium insidiosum, Pythiosis, Human emerging pathogen, Genome sequencing

  9. Pathogenicity characteristics of filamentous fungi strains isolated from processed oat Características de patogenicidade em amostras de fungos filamentosos isolados de aveia processada

    Directory of Open Access Journals (Sweden)

    Eliane N. B. da Silva

    1999-12-01

    Full Text Available Nineteen strains of filamentous fungi isolated from processed oat were tested for pathogenicity factors, based on three parameters: growth at 37oC, production of phospholipase and urease. Aspergillus niveus, Oidiodendron gryseum and Sporothrix cyanescens were positive for the three parameters. The other species were positive only for one or two of them.Dezenove amostras de fungos filamentosos isoladas de aveia processada foram testadas quanto a fatores de patogenicidade, utilizando-se três parâmetros: crescimento a 37oC, atividades fosfolipásica e ureásica. Sporothrix cianescens, Aspergillus niveus e Oidiodendron gryseum apresentaram características de patogenicidade nos três testes realizados. As demais espécies apresentaram características de patogenicidade somente em um ou dois destes parâmetros.

  10. Comparative performance evaluation of multi-metal resistant fungal strains for simultaneous removal of multiple hazardous metals.

    Science.gov (United States)

    Dey, Priyadarshini; Gola, Deepak; Mishra, Abhishek; Malik, Anushree; Kumar, Peeyush; Singh, Dileep Kumar; Patel, Neelam; von Bergen, Martin; Jehmlich, Nico

    2016-11-15

    In the present study, five fungal strains viz., Aspergillus terreus AML02, Paecilomyces fumosoroseus 4099, Beauveria bassiana 4580, Aspergillus terreus PD-17, Aspergillus fumigatus PD-18, were screened for simultaneous multimetal removal. Highest metal tolerance index for each individual metal viz., Cd, Cr, Cu, Ni, Pb and Zn (500mg/L) was recorded for A. fumigatus for the metals (Cd, 0.72; Cu, 0.72; Pb, 1.02; Zn, 0.94) followed by B. bassiana for the metals (Cd, 0.56; Cu, 0.14; Ni, 0.29; Zn, 0.85). Next, the strains were exposed to multiple metal mixture (Cd, Cr, Cu, Ni, Pb and Zn) of various concentrations (6, 12, 18, 30mg/L). Compared to other strains, B. bassiana and A. fumigatus had higher cube root growth (k) constants indicating their better adaptability to multi metal stress. After 72h, multimetal accumulation potential of B. bassiana (26.94±0.07mg/L) and A. fumigatus (27.59±0.09mg/L) were higher than the other strains at initial multimetal concentration of 30mg/L. However, considering the post treatment concentrations of individual metals in multimetal mixture (at all the tested concentrations), A. fumigatus demonstrated exceptional performance and could bring down the concentrations of Cd, Cu, Ni, Pb and Zn below the threshold level for irrigation prescribed by Food and Agriculture Organization (FAO). Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Whole-genome sequencing of Bacillus velezensis LS69, a strain with a broad inhibitory spectrum against pathogenic bacteria.

    Science.gov (United States)

    Liu, Guoqiang; Kong, Yingying; Fan, Yajing; Geng, Ce; Peng, Donghai; Sun, Ming

    2017-05-10

    Bacillus velezensis LS69 was found to exhibit antagonistic activity against a diverse spectrum of pathogenic bacteria. It has one circular chromosome of 3,917,761bp with 3,643 open reading frames. Genome analysis identified ten gene clusters involved in nonribosomal synthesis of polyketides (macrolactin, bacillaene and difficidin), lipopeptides (surfactin, fengycin, bacilysin and iturin A) and bacteriocins (amylolysin and amylocyclicin). In addition, B. velezensis LS69 was found to contain a series of genes involved in enhancing plant growth and triggering plant immunity. Whole genome sequencing of Bacillus velezensis LS69 will provide a basis for elucidation of its biocontrol mechanisms and facilitate its applications in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Use of Green Fluorescent Protein-Transgenic Strains to Study Pathogenic and Nonpathogenic Lifestyles in Colletotrichum acutatum.

    Science.gov (United States)

    Horowitz, Sigal; Freeman, Stanley; Sharon, Amir

    2002-07-01

    ABSTRACT Colletotrichum acutatum, which causes anthracnose disease on strawberry, can also persist on several other plant species without causing disease symptoms. The genetic and molecular bases that determine pathogenic and nonpathogenic lifestyles in C. acutatum are unclear. We developed a transformation system for C. acutatum by electroporation of germinating conidia, and transgenic isolates that express the green fluorescent protein (GFP) were produced. Details of the pathogenic and nonpathogenic lifestyles of C. acutatum were determined by using GFP-transgenic isolates. Major differences between colonization-mediating processes of strawberry and of other plants were observed. On the main host, strawberry, the germinating conidia formed branched, thick hyphae, and large numbers of appressoria were produced that were essential for plant penetration. In strawberry, the fungus developed rapidly, filling the mesophyll with dense mycelium that invaded the cells and caused necrosis of the tissue. In nonpathogenic interactions on pepper, eggplant, and tomato, the conidia germinated, producing thin, straight germ tubes. Appressoria were produced but failed to germinate and penetrate leaf tissue, resulting in epiphytic growth without invasion of the plant. Penetration of the plant occurred only several days after inoculation and was restricted to the intercellular spaces of the first cell layers of infected tissue without causing any visible damage. Much of the new fungal biomass continued to develop on the surface of inoculated organs in the nonpathogenic interaction. The differences in fungal development on strawberry compared with the other plant species suggest that signal molecules, which may be present only in strawberry, trigger appressorial germination and penetration of the primary host.

  13. ɑ-Synuclein strains and seeding in Parkinson's disease, incidental Lewy body disease, dementia with Lewy bodies and multiple system atrophy: similarities and differences.

    Science.gov (United States)

    Peelaerts, W; Bousset, L; Baekelandt, V; Melki, R

    2018-04-27

    Several age-related neurodegenerative disorders are characterized by the deposition of aberrantly folded endogenous proteins. These proteins have prion-like propagation and amplification properties but so far appear nontransmissible between individuals. Because of the features they share with the prion protein, PrP, the characteristics of pathogenic protein aggregates in several progressive brain disorders, including different types of Lewy body diseases (LBDs), such as Parkinson's disease (PD), multiple system atrophy (MSA) and dementia with Lewy bodies (DLB), have been actively investigated. Even though the pleomorphic nature of these syndromes might suggest different underlying causes, ɑ-synuclein (ɑSyn) appears to play an important role in this heterogeneous group of diseases (the synucleinopathies). An attractive hypothesis is that different types of ɑSyn protein assemblies have a unique and causative role in distinct synucleinopathies. We will discuss the recent research progress on ɑSyn assemblies involved in PD, MSA and DLB; their behavior as strains; current spreading hypotheses; their ability to seed centrally and peripherally; and their implication for disease pathogenesis.

  14. Multiple strategies to improve sensitivity, speed and robustness of isothermal nucleic acid amplification for rapid pathogen detection

    Directory of Open Access Journals (Sweden)

    Lemieux Bertrand

    2011-05-01

    Full Text Available Abstract Background In the past decades the rapid growth of molecular diagnostics (based on either traditional PCR or isothermal amplification technologies meet the demand for fast and accurate testing. Although isothermal amplification technologies have the advantages of low cost requirements for instruments, the further improvement on sensitivity, speed and robustness is a prerequisite for the applications in rapid pathogen detection, especially at point-of-care diagnostics. Here, we describe and explore several strategies to improve one of the isothermal technologies, helicase-dependent amplification (HDA. Results Multiple strategies were approached to improve the overall performance of the isothermal amplification: the restriction endonuclease-mediated DNA helicase homing, macromolecular crowding agents, and the optimization of reaction enzyme mix. The effect of combing all strategies was compared with that of the individual strategy. With all of above methods, we are able to detect 50 copies of Neisseria gonorrhoeae DNA in just 20 minutes of amplification using a nearly instrument-free detection platform (BESt™ cassette. Conclusions The strategies addressed in this proof-of-concept study are independent of expensive equipments, and are not limited to particular primers, targets or detection format. However, they make a large difference in assay performance. Some of them can be adjusted and applied to other formats of nucleic acid amplification. Furthermore, the strategies to improve the in vitro assays by maximally simulating the nature conditions may be useful in the general field of developing molecular assays. A new fast molecular assay for Neisseria gonorrhoeae has also been developed which has great potential to be used at point-of-care diagnostics.

  15. Introgression of ivermectin resistance genes into a susceptible Haemonchus contortus strain by multiple backcrossing.

    Directory of Open Access Journals (Sweden)

    Elizabeth Redman

    2012-02-01

    Full Text Available Anthelmintic drug resistance in livestock parasites is already widespread and in recent years there has been an increasing level of anthelmintic drug selection pressure applied to parasitic nematode populations in humans leading to concerns regarding the emergence of resistance. However, most parasitic nematodes, particularly those of humans, are difficult experimental subjects making mechanistic studies of drug resistance extremely difficult. The small ruminant parasitic nematode Haemonchus contortus is a more amenable model system to study many aspects of parasite biology and investigate the basic mechanisms and genetics of anthelmintic drug resistance. Here we report the successful introgression of ivermectin resistance genes from two independent ivermectin resistant strains, MHco4(WRS and MHco10(CAVR, into the susceptible genome reference strain MHco3(ISE using a backcrossing approach. A panel of microsatellite markers were used to monitor the procedure. We demonstrated that after four rounds of backcrossing, worms that were phenotypically resistant to ivermectin had a similar genetic background to the susceptible reference strain based on the bulk genotyping with 18 microsatellite loci and individual genotyping with a sub-panel of 9 microsatellite loci. In addition, a single marker, Hcms8a20, showed evidence of genetic linkage to an ivermectin resistance-conferring locus providing a starting point for more detailed studies of this genomic region to identify the causal mutation(s. This work presents a novel genetic approach to study anthelmintic resistance and provides a "proof-of-concept" of the use of forward genetics in an important model strongylid parasite of relevance to human hookworms. The resulting strains provide valuable resources for candidate gene studies, whole genome approaches and for further genetic analysis to identify ivermectin resistance loci.

  16. Production of multiple bacteriocins from a single locus by gastrointestinal strains of Lactobacillus salivarius.

    Science.gov (United States)

    O'Shea, Eileen F; O'Connor, Paula M; Raftis, Emma J; O'Toole, Paul W; Stanton, Catherine; Cotter, Paul D; Ross, R Paul; Hill, Colin

    2011-12-01

    Bacteriocins produced by Lactobacillus salivarius isolates derived from a gastrointestinal origin have previously demonstrated efficacy for in vivo protection against Listeria monocytogenes infection. In this study, comparative genomic analysis was employed to investigate the intraspecies diversity of seven L. salivarius isolates of human and porcine intestinal origin, based on the genome of the well-characterized bacteriocin-producing strain L. salivarius UCC118. This revealed a highly conserved megaplasmid-borne gene cluster in these strains involved in the regulation and secretion of two-component class IIb bacteriocins. However, considerable intraspecific variation was observed in the structural genes encoding the bacteriocin peptides. They ranged from close relatives of abp118, such as salivaricin P, which differs by 2 amino acids, to completely novel bacteriocins, such as salivaricin T, which is characterized in this study. Salivaricin T inhibits closely related lactobacilli and bears little homology to previously characterized salivaricins. Interestingly, the two peptides responsible for salivaricin T activity, SalTα and SalTβ, share considerable identity with the component peptides of thermophilin 13, a bacteriocin produced by Streptococcus thermophilus. Furthermore, the salivaricin locus of strain DPC6488 also encodes an additional novel one-component class IId anti-listerial bacteriocin, salivaricin L. These findings suggest a high level of redundancy in the bacteriocins that can be produced by intestinal L. salivarius isolates using the same enzymatic production and export machinery. Such diversity may contribute to their ability to dominate and compete within the complex microbiota of the mammalian gut.

  17. Activation of Multiple Antibiotic Resistance in Uropathogenic Escherichia coli Strains by Aryloxoalcanoic Acid Compounds

    Science.gov (United States)

    Balagué, Claudia; Véscovi, Eleonora García

    2001-01-01

    Clofibric and ethacrynic acids are prototypical pharmacological agents administered in the treatment of hypertrigliceridemia and as a diuretic agent, respectively. They share with 2,4-dichlorophenoxyacetic acid (the widely used herbicide known as 2,4-D) a chlorinated phenoxy structural moiety. These aryloxoalcanoic agents (AOAs) are mainly excreted by the renal route as unaltered or conjugated active compounds. The relatedness of these agents at the structural level and their potential effect on therapeutically treated or occupationally exposed individuals who are simultaneously undergoing a bacterial urinary tract infection led us to analyze their action on uropathogenic, clinically isolated Escherichia coli strains. We found that exposure to these compounds increases the bacterial resistance to an ample variety of antibiotics in clinical isolates of both uropathogenic and nonpathogenic E. coli strains. We demonstrate that the AOAs induce an alteration of the bacterial outer membrane permeability properties by the repression of the major porin OmpF in a micF-dependent process. Furthermore, we establish that the antibiotic resistance phenotype is primarily due to the induction of the MarRAB regulatory system by the AOAs, while other regulatory pathways that also converge into micF modulation (OmpR/EnvZ, SoxRS, and Lrp) remained unaltered. The fact that AOAs give rise to uropathogenic strains with a diminished susceptibility to antimicrobials highlights the impact of frequently underestimated or ignored collateral effects of chemical agents. PMID:11353631

  18. Biogenic nanosilver incorporated reverse osmosis membrane for antibacterial and antifungal activities against selected pathogenic strains: an enhanced eco-friendly water disinfection approach.

    Science.gov (United States)

    Manjumeena, R; Duraibabu, D; Sudha, J; Kalaichelvan, P T

    2014-01-01

    Reverse osmosis (RO) membranes have been used extensively in water desalination plants, waste water treatment in industries, agricultural farms and drinking water production applications. The objective of this work is to impart antibacterial and antifungal activities to commercially available RO membrane used in water purification systems by incorporating biogenic silver nanoparticles(AgNPs) synthesized using Rosa indica wichuriana hybrid leaf extract. The morphology and surface topography of uncoated and AgNPs-coated RO membrane were studied using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Elemental composition of the AgNPs-coated RO membrane was analyzed by energy-dispersive X-ray spectroscopy (EDAX). The functional groups were identified by Fourier Transform Infrared spectroscopy (FT-IR). Hydrophilicity of the uncoated and AgNPs-coated RO membrane was analyzed using water contact angle measurements. The thermal properties were studied by thermogravimetric analysis (TGA). The AgNPs incorporated RO membrane exhibited good antibacterial and antifungal activities against pathogenic bacterial strains such as E. coli, S. aureus, M. luteus, K. pneumoniae, and P. aeruginosa and fungal strains such as Candida tropicalis, C. krusei, C. glabrata, and C. albicans.

  19. Evaluation of Anti-adherent Activity of Excretions of Irradiated Lucilia sericata Maggot and Certain Essential Oils against Some Pathogenic Bacterial Strains

    International Nuclear Information System (INIS)

    Eltablawy, S.Y.; Amin, M.M.

    2011-01-01

    Essential Oils are widely used for their medicinal properties. They block adhesion and colonization of pathogenic microbes to epithelial cells which associated with bacterial resistance to antibiotics. So, this study investigates the effect of Lu cilia sacarato (flesh fly-an ectoparasitic) excretions of non-irradiated and irradiated maggot and some essential oils on biofilm formation by tube method, antimicrobial susceptibility by agar disc diffusion method as well as on their anti-adherent activity by spectrophotometric method. The results showed that excretions and secretions (E/S) of non-irradiated and irradiated maggots (at 20 Gy), as well as (clove and cinnamon oils) did not have antibacterial activity against the tested bacterial strains Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (St. aureus) and Staphylococcus epidermidis (St. epidermidis) except marjoram oil which has low antimicrobial activity against all the tested strains. The results also showed that the most potent oil was clove which decrease biofilm of P. aeruginosa by 83%, followed by marjoram (69%), then E/S of non-irradiated maggots (66%). Whiles, biofilm was less affected by cinnamon oil and E/S of irradiated maggots by 50 % and 36%, respectively. In addition, clove oil and E/S of non-irradiated maggots affect the pre-adhered biofilm of P. aeruginosa by 57 and 45 %, respectively. Conclusion: Clove oil flowed by marjoram had anti-adherent effect on P. aeruginosa. Greater inhibition of adhesion was observed by excretions of non-irradiated lucilia sericata.

  20. Non-contiguous finished genome sequence of the opportunistic oral pathogen Prevotella multisaccharivorax type strain (PPPA20T)

    Energy Technology Data Exchange (ETDEWEB)

    Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Gronow, Sabine [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Lu, Megan [Los Alamos National Laboratory (LANL); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Hammon, Nancy [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, Cliff [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Ivanova, N [U.S. Department of Energy, Joint Genome Institute

    2011-01-01

    Prevotella multisaccharivorax Sakamoto et al. 2005 is a species of the large genus Prevotella, which belongs to the family Prevotellaceae. The species is of medical interest because its members are able to cause diseases in the human oral cavity such as periodontitis, root caries and others. Although 77 Prevotella genomes have already been sequenced or are targeted for sequencing, this is only the second completed genome sequence of a type strain of a species within the genus Prevotella to be published. The 3,388,644 bp long genome is assembled in three non-contiguous contigs, harbors 2,876 protein-coding and 75 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  1. Biofilm spatial organization by the emerging pathogen Campylobacter jejuni: comparison between NCTC 11168 and 81-176 strains under microaerobic and oxygen-enriched conditions.

    Science.gov (United States)

    Turonova, Hana; Briandet, Romain; Rodrigues, Ramila; Hernould, Mathieu; Hayek, Nabil; Stintzi, Alain; Pazlarova, Jarmila; Tresse, Odile

    2015-01-01

    During the last years, Campylobacter has emerged as the leading cause of bacterial foodborne infections in developed countries. Described as an obligate microaerophile, Campylobacter has puzzled scientists by surviving a wide range of environmental oxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidative damage from macrophages to cause human infection. In this study, confocal laser scanning microscopy (CLSM) was used to explore the biofilm development of two well-described Campylobacter jejuni strains (NCTC 11168 and 81-176) prior to or during cultivation under oxygen-enriched conditions. Quantitative and qualitative appraisal indicated that C. jejuni formed finger-like biofilm structures with an open ultrastructure for 81-176 and a multilayer-like structure for NCTC 11168 under microaerobic conditions (MAC). The presence of motile cells within the biofilm confirmed the maturation of the C. jejuni 81-176 biofilm. Acclimation of cells to oxygen-enriched conditions led to significant enhancement of biofilm formation during the early stages of the process. Exposure to these conditions during biofilm cultivation induced an even greater biofilm development for both strains, indicating that oxygen demand for biofilm formation is higher than for planktonic growth counterparts. Overexpression of cosR in the poorer biofilm-forming strain, NCTC 11168, enhanced biofilm development dramatically by promoting an open ultrastructure similar to that observed for 81-176. Consequently, the regulator CosR is likely to be a key protein in the maturation of C. jejuni biofilm, although it is not linked to oxygen stimulation. These unexpected data advocate challenging studies by reconsidering the paradigm of fastidious requirements for C. jejuni growth when various subpopulations (from quiescent to motile cells) coexist in biofilms. These findings constitute a clear example of a survival strategy used by this emerging human pathogen.

  2. Biofilm spatial organization by the emerging pathogen Campylobacter jejuni: comparison between NCTC 11168 and 81-176 strains under microaerobic and oxygen-enriched conditions

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    Hana eTuronova

    2015-07-01

    Full Text Available During the last years, Campylobacter has emerged as the leading cause of bacterial foodborne infections in developed countries. Described as an obligate microaerophile, Campylobacter has puzzled scientists by surviving a wide range of environmental oxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidative damage from macrophages to cause human infection. In this study, confocal laser scanning microscopy was used to explore the biofilm development of two well-described Campylobacter jejuni strains (NCTC 11168 and 81-176 prior to or during cultivation under oxygen-enriched conditions. Quantitative and qualitative appraisal indicated that C. jejuni formed finger-like biofilm structures with an open ultrastructure for 81-176 and a multilayer-like structure for NCTC 11168 under microaerobic conditions. The presence of motile cells within the biofilm confirmed the maturation of the C. jejuni 81-176 biofilm. Acclimation of cells to oxygen-enriched conditions led to significant enhancement of biofilm formation during the early stages of the process. Exposure to these conditions during biofilm cultivation induced an even greater biofilm development for both strains, indicating that oxygen demand for biofilm formation is higher than for planktonic growth counterparts. Overexpression of cosR in the poorer biofilm-forming strain, NCTC 11168, enhanced biofilm development dramatically by promoting an open ultrastructure similar to that observed for 81-176. Consequently, the regulator CosR is likely to be a key protein in the maturation of C. jejuni biofilm, although it is not linked to oxygen stimulation. These unexpected data advocate challenging studies by reconsidering the paradigm of fastidious requirements for C. jejuni growth when various subpopulations (from quiescent to motile cells coexist in biofilms. These findings constitute a clear example of a survival strategy used by this emerging human pathogen.

  3. Survey of surface proteins from the pathogenic Mycoplasma hyopneumoniae strain 7448 using a biotin cell surface labeling approach.

    Science.gov (United States)

    Reolon, Luciano Antonio; Martello, Carolina Lumertz; Schrank, Irene Silveira; Ferreira, Henrique Bunselmeyer

    2014-01-01

    The characterization of the repertoire of proteins exposed on the cell surface by Mycoplasma hyopneumoniae (M. hyopneumoniae), the etiological agent of enzootic pneumonia in pigs, is critical to understand physiological processes associated with bacterial infection capacity, survival and pathogenesis. Previous in silico studies predicted that about a third of the genes in the M. hyopneumoniae genome code for surface proteins, but so far, just a few of them have experimental confirmation of their expression and surface localization. In this work, M. hyopneumoniae surface proteins were labeled in intact cells with biotin, and affinity-captured biotin-labeled proteins were identified by a gel-based liquid chromatography-tandem mass spectrometry approach. A total of 20 gel slices were separately analyzed by mass spectrometry, resulting in 165 protein identifications corresponding to 59 different protein species. The identified surface exposed proteins better defined the set of M. hyopneumoniae proteins exposed to the host and added confidence to in silico predictions. Several proteins potentially related to pathogenesis, were identified, including known adhesins and also hypothetical proteins with adhesin-like topologies, consisting of a transmembrane helix and a large tail exposed at the cell surface. The results provided a better picture of the M. hyopneumoniae cell surface that will help in the understanding of processes important for bacterial pathogenesis. Considering the experimental demonstration of surface exposure, adhesion-like topology predictions and absence of orthologs in the closely related, non-pathogenic species Mycoplasma flocculare, several proteins could be proposed as potential targets for the development of drugs, vaccines and/or immunodiagnostic tests for enzootic pneumonia.

  4. Survey of surface proteins from the pathogenic Mycoplasma hyopneumoniae strain 7448 using a biotin cell surface labeling approach.

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    Luciano Antonio Reolon

    Full Text Available The characterization of the repertoire of proteins exposed on the cell surface by Mycoplasma hyopneumoniae (M. hyopneumoniae, the etiological agent of enzootic pneumonia in pigs, is critical to understand physiological processes associated with bacterial infection capacity, survival and pathogenesis. Previous in silico studies predicted that about a third of the genes in the M. hyopneumoniae genome code for surface proteins, but so far, just a few of them have experimental confirmation of their expression and surface localization. In this work, M. hyopneumoniae surface proteins were labeled in intact cells with biotin, and affinity-captured biotin-labeled proteins were identified by a gel-based liquid chromatography-tandem mass spectrometry approach. A total of 20 gel slices were separately analyzed by mass spectrometry, resulting in 165 protein identifications corresponding to 59 different protein species. The identified surface exposed proteins better defined the set of M. hyopneumoniae proteins exposed to the host and added confidence to in silico predictions. Several proteins potentially related to pathogenesis, were identified, including known adhesins and also hypothetical proteins with adhesin-like topologies, consisting of a transmembrane helix and a large tail exposed at the cell surface. The results provided a better picture of the M. hyopneumoniae cell surface that will help in the understanding of processes important for bacterial pathogenesis. Considering the experimental demonstration of surface exposure, adhesion-like topology predictions and absence of orthologs in the closely related, non-pathogenic species Mycoplasma flocculare, several proteins could be proposed as potential targets for the development of drugs, vaccines and/or immunodiagnostic tests for enzootic pneumonia.

  5. Study of the Antibacterial Activity of Methanolic and Aqueous Extracts of Myrtus communis on Pathogenic Strains Causing Infection

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    Behrooz Alizadeh Behbahani

    2016-02-01

    Full Text Available Background Medicine plants have been used as sources of medicine in virtually all cultures. During the last decade, the use of traditional medicine (TM has been expanded globally and is gaining popularity. Objectives The antimicrobial activities of methanol and water extracts of Myrtus communis L. leaves were evaluated in this study. Materials and Methods In this experimental study, the tests were carried out using disk agar diffusion method at four extract concentrations (5, 10, 15 and 20 mg/mL. The MICs and MBCs of the extracts of M. communis were determined by agar dilution method. Average results were reported as the mean and standard error (mean ± SE and SPSS-18 statistical software, oneway ANOVA followed by Turkey’s test were used to do inter-group comparison, while considering P ≤ 0.05 as the significance level. Results Methanol extract of M. communis exhibited significant antibacterial activity in the concentration of 20 mg/mL (P ≤ 0.05 against Staphylococcus epidermidis and Enterococcus faecalis with a greater inhibition zone of 20 mm, while a 14 mm zone of inhibition was observed in Escherichia coli and Shigella flexneri. The minimum inhibitory concentration (MIC of the extracts ranged between 2 mg/mL and 128 mg/mL while the minimum bactericidal concentration (MBC ranged between 4 mg/mL and 256 mg/mL. Conclusions The study showed that species, strains and concentrations of M. communis extract are of those factors that may influence the sensitivity of the tested bacteria. A significant correlation was observed between zone of inhibition and concentration of extract.

  6. Comparative pathogenesis in specific-pathogen-free chickens of two strains of avian hepatitis E virus recovered from a chicken with Hepatitis-Splenomegaly syndrome and from a clinically healthy chicken.

    Science.gov (United States)

    Billam, P; LeRoith, T; Pudupakam, R S; Pierson, F W; Duncan, R B; Meng, X J

    2009-11-18

    Avian hepatitis E virus (avian HEV) is the primary causative agent of Hepatitis-Splenomegaly (HS) syndrome in chickens. Recently, a genetically unique strain of avian HEV, designated avian HEV-VA, was recovered from healthy chickens in Virginia. The objective of this study was to experimentally compare the pathogenicity of the prototype strain recovered from a chicken with HS syndrome and the avian HEV-VA strain in specific-pathogen-free chickens. An infectious stock of the avian HEV-VA strain was first generated and its infectivity titer determined in chickens. For the comparative pathogenesis study, 54 chickens of 6-week-old were assigned to 3 groups of 18 chickens each. The group 1 chickens were each intravenously inoculated with 5x10(2.5) 50% chicken infectious dose of the prototype strain. The group 2 received the same dose of the avian HEV-VA strain, and the group 3 served as negative controls. Six chickens from each group were necropsied at 2, 3 and 4 weeks post-inoculation (wpi). Most chickens in both inoculated groups seroconverted by 3wpi, and the mean anti-avian HEV antibody titers were higher for the prototype strain group than the avian HEV-VA strain group. There was no significant difference in the patterns of viremia and fecal virus shedding. Blood analyte profiles did not differ between treatment groups except for serum creatine phosphokinase levels which were higher for prototype avian HEV group than avian HEV-VA group. The hepatic lesion score was higher for the prototype strain group than the other two groups. The results indicated that the avian HEV-VA strain is only slightly attenuated compared to the prototype strain, suggesting that the full spectrum of HS syndrome is likely associated with other co-factors.

  7. Inactivation of the Major Hemolysin Gene Influences Expression of the Nonribosomal Peptide Synthetase Gene swrA in the Insect Pathogen Serratia sp. Strain SCBI.

    Science.gov (United States)

    Petersen, Lauren M; LaCourse, Kaitlyn; Schöner, Tim A; Bode, Helge; Tisa, Louis S

    2017-11-01

    Hemolysins are important virulence factors for many bacterial pathogens, including Serratia marcescens The role of the major hemolysin gene in the insect pathogen Serratia sp. strain SCBI was investigated using both forward and reverse-genetics approaches. Introduction of the major hemolysin gene into Escherichia coli resulted in a gain of both virulence and hemolytic activity. Inactivation of this hemolysin in Serratia sp. SCBI resulted in a loss of hemolysis but did not attenuate insecticidal activity. Unexpectedly, inactivation of the hemolysin gene in Serratia sp. SCBI resulted in significantly increased motility and increased antimicrobial activity. Reverse transcription-quantitative PCR (qRT-PCR) analysis of mutants with a disrupted hemolysin gene showed a dramatic increase in mRNA levels of a nonribosomal peptide synthetase gene, swrA , which produces the surfactant serrawettin W2. Mutation of the swrA gene in Serratia sp. SCBI resulted in highly varied antibiotic activity, motility, virulence, and hemolysis phenotypes that were dependent on the site of disruption within this 17.75-kb gene. When introduced into E. coli , swrA increases rates of motility and confers antimicrobial activity. While it is unclear how inactivation of the major hemolysin gene influences the expression of swrA , these results suggest that swrA plays an important role in motility and antimicrobial activity in Serratia sp. SCBI. IMPORTANCE The opportunistic Gram-negative bacteria of the genus Serratia are widespread in the environment and can cause human illness. A comparative genomics analysis between Serratia marcescens and a new Serratia species from South Africa, termed Serratia sp. strain SCBI, shows that these two organisms are closely related but differ in pathogenesis. S. marcescens kills Caenorhabditis nematodes, while Serratia sp. SCBI is not harmful and forms a beneficial association with them. This distinction presented the opportunity to investigate potential differences

  8. An immuno-epidemiological model with threshold delay: a study of the effects of multiple exposures to a pathogen.

    Science.gov (United States)

    Qesmi, Redouane; Heffernan, Jane M; Wu, Jianhong

    2015-01-01

    An immuno-epidemiological model of pathogen transmission is developed. This model incorporates two main features: (i) the epidemiological model includes within-host pathogen dynamics for an infectious disease, (ii) the susceptible individuals to the infection experience a series of exposures via the pathogen before becoming infectious. It is shown that this model leads naturally to a system of differential delay equations of the threshold type and that these equations can be transformed, in a biologically natural way, to differential equations with state-dependent delay. An interesting dynamical behavior of the model is the bistability phenomena, when the basic reproductive ratio R0 is less than unity, which raises many new challenges to effective infection control.

  9. An outbreak of multiple norovirus strains on a cruise ship in China, 2014.

    Science.gov (United States)

    Wang, X; Yong, W; Shi, L; Qiao, M; He, M; Zhang, H; Guo, B; Xie, G; Zhang, M; Jin, M; Ding, J

    2016-01-01

    To determine the cause of an outbreak of acute gastroenteritis that occurred on a cruise ship sailing along the Yangzi River from Chongqing to Nanjing, China. Noroviruses were identified by reverse transcription-PCR (RT-PCR) in rectal swabs from 34 of 54 subjects tested (63·0%). Sequencing and genotyping showed that noroviruses of up to seven different genotypes circulated in this outbreak: noroviruses GI.1, GI.2, GI.3, GI.4, GI.8, GI.9 and an uncommon strain GII.17. Common genotypes were not identified in this event. None of the food or water samples were tested positive for noroviruses. We suspected that it was a point-source infection due to contaminated water or food harvested from contaminated water, taking account of the co-existence of diverse norovirus genotypes. In this study, we presented the molecular investigation of a norovirus outbreak on a cruise in China. We revealed that the outbreak was caused by several different norovirus genotypes and analysed the possible source of infection as well, thus facilitating the evaluation of epidemiological issues regarding noroviruses in this area. © 2015 The Society for Applied Microbiology.

  10. Multilocus sequence typing, biochemical and antibiotic resistance characterizations reveal diversity of North American strains of the honey bee pathogen Paenibacillus larvae.

    Science.gov (United States)

    Krongdang, Sasiprapa; Evans, Jay D; Pettis, Jeffery S; Chantawannakul, Panuwan

    2017-01-01

    Paenibacillus larvae is a Gram positive bacterium and the causative agent of the most widespread fatal brood disease of honey bees, American foulbrood (AFB). A total of thirty-three independent Paenibacillus larvae isolates from various geographical origins in North America and five reference strains were investigated for genetic diversity using multilocus sequence typing (MLST). This technique is regarded to be a powerful tool for epidemiological studies of pathogenic bacteria and is widely used in genotyping assays. For MLST, seven housekeeping gene loci, ilvD (dihydroxy-acid dyhydrogenase), tri (triosephosphate isomerase), purH (phospharibosyl-aminoimidazolecarboxamide), recF (DNA replication and repair protein), pyrE (orotate phosphoribosyltransferase), sucC (succinyl coenzyme A synthetase β subunit) and glpF (glycerol uptake facilitator protein) were studied and applied for primer designs. Previously, ERIC type DNA fingerprinting was applied to these same isolates and the data showed that almost all represented the ERIC I type, whereas using BOX-PCR gave an indication of more diversity. All isolates were screened for resistance to four antibiotics used by U.S. beekeepers, showing extensive resistance to tetracycline and the first records of resistance to tylosin and lincomycin. Our data highlight the intraspecies relationships of P. larvae and the potential application of MLST methods in enhancing our understanding of epidemiological relationships among bacterial isolates of different origins.

  11. Multilocus sequence typing, biochemical and antibiotic resistance characterizations reveal diversity of North American strains of the honey bee pathogen Paenibacillus larvae.

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    Sasiprapa Krongdang

    Full Text Available Paenibacillus larvae is a Gram positive bacterium and the causative agent of the most widespread fatal brood disease of honey bees, American foulbrood (AFB. A total of thirty-three independent Paenibacillus larvae isolates from various geographical origins in North America and five reference strains were investigated for genetic diversity using multilocus sequence typing (MLST. This technique is regarded to be a powerful tool for epidemiological studies of pathogenic bacteria and is widely used in genotyping assays. For MLST, seven housekeeping gene loci, ilvD (dihydroxy-acid dyhydrogenase, tri (triosephosphate isomerase, purH (phospharibosyl-aminoimidazolecarboxamide, recF (DNA replication and repair protein, pyrE (orotate phosphoribosyltransferase, sucC (succinyl coenzyme A synthetase β subunit and glpF (glycerol uptake facilitator protein were studied and applied for primer designs. Previously, ERIC type DNA fingerprinting was applied to these same isolates and the data showed that almost all represented the ERIC I type, whereas using BOX-PCR gave an indication of more diversity. All isolates were screened for resistance to four antibiotics used by U.S. beekeepers, showing extensive resistance to tetracycline and the first records of resistance to tylosin and lincomycin. Our data highlight the intraspecies relationships of P. larvae and the potential application of MLST methods in enhancing our understanding of epidemiological relationships among bacterial isolates of different origins.

  12. Use of multiple molecular subtyping techniques to investigate a Legionnaires' disease outbreak due to identical strains at two tourist lodges.

    Science.gov (United States)

    Mamolen, M; Breiman, R F; Barbaree, J M; Gunn, R A; Stone, K M; Spika, J S; Dennis, D T; Mao, S H; Vogt, R L

    1993-10-01

    A multistate outbreak of Legionnaires' disease occurred among nine tour groups of senior citizens returning from stays at one of two lodges in a Vermont resort in October 1987. Interviews and serologic studies of 383 (85%) of the tour members revealed 17 individuals (attack rate, 4.4%) with radiologically documented pneumonia and laboratory evidence of legionellosis. A survey of tour groups staying at four nearby lodges and of Vermont-area medical facilities revealed no additional cases. Environmental investigation of common tour stops revealed no likely aerosol source of Legionella infection outside the lodges. Legionella pneumophila serogroup 1 was isolated from water sources at both implicated lodges, and the monoclonal antibody subtype matched those of the isolates from six patients from whom clinical isolates were obtained. The cultures reacted with monoclonal antibodies MAB1, MAB2, 33G2, and 144C2 to yield a 1,2,5,7 or a Benidorm 030E pattern. The strains were also identical by alloenzyme electrophoresis and DNA ribotyping techniques. The epidemiologic and laboratory data suggest that concurrent outbreaks occurred following exposures to the same L. pneumophila serogroup 1 strain at two separate lodges. Multiple molecular subtyping techniques can provide essential information for epidemiologic investigations of Legionnaires' disease.

  13. Influence of strain relaxation on the optical properties of InGaN/GaN multiple quantum well nanorods

    International Nuclear Information System (INIS)

    Wang, Q; Bai, J; Gong, Y P; Wang, T

    2011-01-01

    Optical investigation has been carried out on InGaN/GaN nanorod structures with different indium compositions, fabricated from InGaN/GaN multiple quantum well (MQW) epitaxial wafers using a self-organized nickel nano-mask and subsequent dry etching techniques. In comparison with the as-grown InGaN/GaN MQWs, the internal quantum efficiencies of the nanorods are significantly improved, in particular, for the green InGaN/GaN nanorods with a high indium composition, the internal quantum efficiency is enhanced by a factor of 8, much larger than the enhancement factor of 3.4 for the blue InGaN/GaN nanorods. X-ray reciprocal space mapping (RSM) measurements have been performed in order to quantitatively evaluate the stain relaxation in the nanorods, demonstrating that the majority of strain in InGaN/GaN MQWs can be relaxed as a result of fabrication into nanorods. The excitation-power-dependent photoluminescence measurements have also clearly shown that a significant reduction in the strain-induced quantum confined stark effect has occurred to the nanorod structures.

  14. Genotyping of Bacillus anthracis strains based on automated capillary 25-loci Multiple Locus Variable-Number Tandem Repeats Analysis

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    Ciervo Alessandra

    2006-04-01

    Full Text Available Abstract Background The genome of Bacillus anthracis, the etiological agent of anthrax, is highly monomorphic which makes differentiation between strains difficult. A Multiple Locus Variable-number tandem repeats (VNTR Analysis (MLVA assay based on 20 markers was previously described. It has considerable discrimination power, reproducibility, and low cost, especially since the markers proposed can be typed by agarose-gel electrophoresis. However in an emergency situation, faster genotyping and access to representative databases is necessary. Results Genotyping of B. anthracis reference strains and isolates from France and Italy was done using a 25 loci MLVA assay combining 21 previously described loci and 4 new ones. DNA was amplified in 4 multiplex PCR reactions and the length of the resulting 25 amplicons was estimated by automated capillary electrophoresis. The results were reproducible and the data were consistent with other gel based methods once differences in mobility patterns were taken into account. Some alleles previously unresolved by agarose gel electrophoresis could be resolved by capillary electrophoresis, thus further increasing the assay resolution. One particular locus, Bams30, is the result of a recombination between a 27 bp tandem repeat and a 9 bp tandem repeat. The analysis of the array illustrates the evolution process of tandem repeats. Conclusion In a crisis situation of suspected bioterrorism, standardization, speed and accuracy, together with the availability of reference typing data are important issues, as illustrated by the 2001 anthrax letters event. In this report we describe an upgrade of the previously published MLVA method for genotyping of B. anthracis and apply the method to the typing of French and Italian B. anthracis strain collections. The increased number of markers studied compared to reports using only 8 loci greatly improves the discrimination power of the technique. An Italian strain belonging to the

  15. The Epstein-Barr Virus BART miRNA Cluster of the M81 Strain Modulates Multiple Functions in Primary B Cells

    Science.gov (United States)

    Lin, Xiaochen; Tsai, Ming-Han; Shumilov, Anatoliy; Poirey, Remy; Bannert, Helmut; Middeldorp, Jaap M.; Feederle, Regina; Delecluse, Henri-Jacques

    2015-01-01

    The Epstein-Barr virus (EBV) is a B lymphotropic virus that infects the majority of the human population. All EBV strains transform B lymphocytes, but some strains, such as M81, also induce spontaneous virus replication. EBV encodes 22 microRNAs (miRNAs) that form a cluster within the BART region of the virus and have been previously been found to stimulate tumor cell growth. Here we describe their functions in B cells infected by M81. We found that the BART miRNAs are downregulated in replicating cells, and that exposure of B cells in vitro or in vivo in humanized mice to a BART miRNA knockout virus resulted in an increased proportion of spontaneously replicating cells, relative to wild type virus. The BART miRNAs subcluster 1, and to a lesser extent subcluster 2, prevented expression of BZLF1, the key protein for initiation of lytic replication. Thus, multiple BART miRNAs cooperate to repress lytic replication. The BART miRNAs also downregulated pro- and anti-apoptotic mediators such as caspase 3 and LMP1, and their deletion did not sensitize B-cells to apoptosis. To the contrary, the majority of humanized mice infected with the BART miRNA knockout mutant developed tumors more rapidly, probably due to enhanced LMP1 expression, although deletion of the BART miRNAs did not modify the virus transforming abilities in vitro. This ability to slow cell growth could be confirmed in non-humanized immunocompromized mice. Injection of resting B cells exposed to a virus that lacks the BART miRNAs resulted in accelerated tumor growth, relative to wild type controls. Therefore, we found that the M81 BART miRNAs do not enhance B-cell tumorigenesis but rather repress it. The repressive effects of the BART miRNAs on potentially pathogenic viral functions in infected B cells are likely to facilitate long-term persistence of the virus in the infected host. PMID:26694854

  16. Antibacterial effect of Allium sativum cloves and Zingiber officinale rhizomes against multiple-drug resistant clinical pathogens.

    Science.gov (United States)

    Karuppiah, Ponmurugan; Rajaram, Shyamkumar

    2012-08-01

    To evaluate the antibacterial properties of Allium sativum (garlic) cloves and Zingiber officinale (ginger) rhizomes against multi-drug resistant clinical pathogens causing nosocomial infection. The cloves of garlic and rhizomes of ginger were extracted with 95% (v/v) ethanol. The ethanolic extracts were subjected to antibacterial sensitivity test against clinical pathogens. Anti-bacterial potentials of the extracts of two crude garlic cloves and ginger rhizomes were tested against five gram negative and two gram positive multi-drug resistant bacteria isolates. All the bacterial isolates were susceptible to crude extracts of both plants extracts. Except Enterobacter sp. and Klebsiella sp., all other isolates were susceptible when subjected to ethanolic extracts of garlic and ginger. The highest inhibition zone was observed with garlic (19.45 mm) against Pseudomonas aeruginosa (P. aeruginosa). The minimal inhibitory concentration was as low as 67.00 µg/mL against P. aeruginosa. Natural spices of garlic and ginger possess effective anti-bacterial activity against multi-drug clinical pathogens and can be used for prevention of drug resistant microbial diseases and further evaluation is necessary.

  17. Elimination of Pathogen Escherichia coli O157:H7 in Ground Beef by a Newly Isolated Strain of Lactobacillus acidophilus during Storage at 5°C

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    Alireza Goodarzi

    2016-06-01

    Full Text Available Background and Objective: Constant use of limited number of lactic acid bacteria species in biopreservation can cause genetic degradation and or rising resistance against food pathogens or antimicrobial substances they produce. For this objective, a newly isolated strain of Lactobacillus acidophilus possessing high antimicrobial activity was evaluated as a candidate for use in biopreservation.Materials and Methods: Antibacterial activity was evaluated by agar disk diffusion method. Hydrogen peroxide amount was measured by Merckoquant Peroxide test strips. Microbiological analysis of the ground beef infected by Escherichia coli O157:H7 and treated by Lactobacillus acidophilus GH 201was done by plating of serial dilution in physiological saline on Tryptose agar.Results and Conclusion: The cells (109 CFU ml-1 of Lactobacillus acidophilus produced significant amount of antibacterial substances mainly hydrogen peroxide (28 and 30 μg ml-1 in sodium phosphate buffer (0.2 M, pH 6.5 and LAPTg at 5°C during submerged cultivation with no growth, respectively. Submerged co-cultivation of Escherichia coli O157:H7 with lactobacilli in LAPTg broth at 5°C reduced the total number of the pathogen more than 2 log for 5 days. In case of solid state cultivation on agar-based medium, the maximum inhibitory zones on Escherichia coli O157:H7 lawn around the disks soaked by different amounts of washed Lactobacillus acidophilus cells appear for one-day cold exposition. The size of inhibition zone depends on the concentration of lactic acid bacteria cells. The cell suspension intended for treatment must contain 108-9CFU ml-1 of lactic acid bacteria. Lactobacillus acidophilus reduced the initial amount (2×105 CFU ml-1 of Escherichia coli O157:H7 in ground beef up to 2 log for 5 days of solid-state co-cultivation. The application of Lactobacillus acidophilus bacteria expanded the shelf-life of ground beef due to inhibition of

  18. CRISPR/Cas9 Mutagenesis of UL21 in Multiple Strains of Herpes Simplex Virus Reveals Differential Requirements for pUL21 in Viral Replication

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    Renée L. Finnen

    2018-05-01

    Full Text Available Studies from multiple laboratories using different strains or species of herpes simplex virus (HSV with deletions in UL21 have yielded conflicting results regarding the necessity of pUL21 in HSV infection. To resolve this discrepancy, we utilized CRISPR/Cas9 mutagenesis to isolate pUL21 deficient viruses in multiple HSV backgrounds, and performed a side-by-side comparison of the cell-to-cell spread and replication phenotypes of these viruses. These analyses confirmed previous studies implicating the involvement of pUL21 in cell-to-cell spread of HSV. Cell-to-cell spread of HSV-2 was more greatly affected by the lack of pUL21 than HSV-1, and strain-specific differences in the requirement for pUL21 in cell-to-cell spread were also noted. HSV-2 strain 186 lacking pUL21 was particularly crippled in both cell-to-cell spread and viral replication in non-complementing cells, in comparison to other HSV strains lacking pUL21, suggesting that the strict requirement for pUL21 by strain 186 may not be representative of the HSV-2 species as a whole. This work highlights CRISPR/Cas9 technology as a useful tool for rapidly constructing deletion mutants of alphaherpesviruses, regardless of background strain, and should find great utility whenever strain-specific differences need to be investigated.

  19. MICROBIAL LOAD AND MULTIPLE DRUG RESISTANCE OF PATHOGENIC BACTERIA ISOLATED FROM FEACES AND BODY SURFACES OF COCKROACHES IN AN URBAN AREA OF SOUTHWESTERN NIGERIA

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    Monsuru Adebayo Adeleke

    2012-06-01

    Full Text Available This study investigates the microbial load and antibiotic susceptibility pattern of pathogenic bacteria isolated from the faeces and body surfaces of cockroaches in Osogbo, Southwestern Nigeria. The cockroaches collected from residential areas and hospital vicinities were screened for microbial load and antibiotic susceptibility pattern using standard protocols. A total of twenty- three microorganisms namely Klebsiella aerogenes, Bacillius cereus, Proteus spp, Staphyloccocus aureus, S. saprophyticus, Enteroccocus faecalis, Staphylococus epididermis, E. coli, Listeria monoctogene, Proteus mirabilis, Citrobacter species, Pseudomonas aeruginosa, Psuedomonas species, Seretia mensence, Candida albicans, Candida spp., Aspergilius spp., A. flavus, A. fumigates, Mucor species and Penicilium species were isolated. The microbial load of the microorganisms was significantly higher in the isolates from hospital as compared with the residential area (p<0.05 with the exception of Canidida species, Mucor and Penicillium which had higher or equal microbial load at the residential areas. All the pathogenic bacteria isolated had multiple resistance to antibiotics most importantly, Ampicillin, Augumentin, Amoxicillin and Septrin (30μg. Efforts geared towards controlling the insects will be indispensable in curbing the wide spread of multi-drug resistant pathogens in the study area.

  20. A reverse genetics system for the Great Lakes strain of viral hemorrhagic septicemia virus: the NV gene is required for pathogenicity

    Science.gov (United States)

    Ammayappan, Arun; Kurath, Gael; Thompson, Tarin M.; Vakharia, Vikram N.

    2011-01-01

    Viral hemorrhagic septicemia virus (VHSV), belonging to the genus Novirhabdovirus in the family of Rhabdoviridae, causes a highly contagious disease of fresh and saltwater fish worldwide. Recently, a novel genotype of VHSV, designated IVb, has invaded the Great Lakes in North America, causing large-scale epidemics in wild fish. An efficient reverse genetics system was developed to generate a recombinant VHSV of genotype IVb from cloned cDNA. The recombinant VHSV (rVHSV) was comparable to the parental wild-type strain both in vitro and in vivo, causing high mortality in yellow perch (Perca flavescens). A modified recombinant VHSV was generated in which the NV gene was substituted with an enhanced green fluorescent protein gene (rVHSV-ΔNV-EGFP), and another recombinant was made by inserting the EGFP gene into the full-length viral clone between the P and M genes (rVHSV-EGFP). The in vitro replication kinetics of rVHSV-EGFP was similar to rVHSV; however, the rVHSV-ΔNV-EGFP grew 2 logs lower. In yellow perch challenges, wtVHSV and rVHSV induced 82-100% cumulative per cent mortality (CPM), respectively, whereas rVHSV-EGFP produced 62% CPM and rVHSV-ΔNV-EGFP caused only 15% CPM. No reversion of mutation was detected in the recovered viruses and the recombinant viruses stably maintained the foreign gene after several passages. These results indicate that the NV gene of VHSV is not essential for viral replication in vitro and in vivo, but it plays an important role in viral replication efficiency and pathogenicity. This system will facilitate studies of VHSV replication, virulence, and production of viral vectored vaccines.

  1. Multiple strains probiotics appear to be the most effective probiotics in the prevention of necrotizing enterocolitis and mortality: An updated meta-analysis.

    Directory of Open Access Journals (Sweden)

    Hung-Yang Chang

    Full Text Available Some oral probiotics have been shown to prevent necrotizing enterocolitis (NEC and decrease mortality effectively in preterm very low birth weight (PVLBW infants. However, it is unclear whether a single probiotic or a mixture of probiotics is most effective for the prevention of NEC.A meta-analysis was conducted by reviewing the most up to date literature to investigate whether multiple strains probiotics are more effective than a single strain in reducing NEC and death in PVLBW infants.Relevant studies were identified by searches of the MEDLINE, EMBASE, and Cochrane CENTRAL databases, from 2001 to 2016.The inclusion criteria were randomized controlled trials of any enteral probiotic supplementation that was initiated within the first 7 days and continued for at least 14 days in preterm infants (≤ 34 weeks' gestation and/or those of a birth weight ≤1500 g.A total of 25 trials (n = 7345 infants were eligible for inclusion in the meta-analysis using a fixed-effects model. Multiple strains probiotics were associated with a marked reduction in the incidence of NEC, with a pooled OR of 0.36 (95% CI, 0.24-0.53; P < .00001. Single strain probiotic using Lactobacillus species had a borderline effect in reducing NEC (OR of 0.60; 95% CI 0.36-1.0; P = .05, but not mortality. Multiple strains probiotics had a greater effectiveness in reducing mortality and were associated with a pooled OR of 0.58 (95% CI, 0.43-0.79; P = .0006. Trials using single strain of Bifidobacterium species and Saccharomyces boulardii did not reveal any beneficial effects in terms of reducing NEC or mortality.This updated report found that multiple strains probiotics appear to be the most feasible and effective strategy for the prevention of NEC and reduction of mortality in PVLBW neonates. Further clinical trials should focus on which probiotic combinations are most effective.

  2. A multiple antibiotic and serum resistant oligotrophic strain, Klebsiella pneumoniae MB45 having novel dfrA30, is sensitive to ZnO QDs

    Directory of Open Access Journals (Sweden)

    Chakrabarti Pinak

    2011-05-01

    Full Text Available Abstract Background The aim of this study was to describe a novel trimethoprim resistance gene cassette, designated dfrA30, within a class 1 integron in a facultatively oligotrophic, multiple antibiotic and human serum resistant test strain, MB45, in a population of oligotrophic bacteria isolated from the river Mahananda; and to test the efficiency of surface bound acetate on zinc oxide quantum dots (ZnO QDs as bactericidal agent on MB45. Methods Diluted Luria broth/Agar (10-3 media was used to cultivate the oligotrophic bacteria from water sample. Multiple antibiotic resistant bacteria were selected by employing replica plate method. A rapid assay was performed to determine the sensitivity/resistance of the test strain to human serum. Variable region of class 1 integron was cloned, sequenced and the expression of gene coding for antibiotic resistance was done in Escherichia coli JM 109. Identity of culture was determined by biochemical phenotyping and 16S rRNA gene sequence analyses. A phylogenetic tree was constructed based on representative trimethoprim resistance-mediating DfrA proteins retrieved from GenBank. Growth kinetic studies for the strain MB45 were performed in presence of varied concentrations of ZnO QDs. Results and conclusions The facultatively oligotrophic strain, MB45, resistant to human serum and ten antibiotics trimethoprim, cotrimoxazole, ampicillin, gentamycin, netilmicin, tobramycin, chloramphenicol, cefotaxime, kanamycin and streptomycin, has been identified as a new strain of Klebsiella pneumoniae. A novel dfr gene, designated as dfrA30, found integrated in class 1 integron was responsible for resistance to trimethoprim in Klebsiella pneumoniae strain MB45. The growth of wild strain MB45 was 100% arrested at 500 mg/L concentration of ZnO QDs. To our knowledge this is the first report on application of ZnO quantum dots to kill multiple antibiotics and serum resistant K. pneumoniae strain.

  3. Mechanism of mercuric chloride resistance in microorganisms. I. Vaporization of a mercury compound from mercuric chloride by multiple drug resistant strains of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Komura, I; Izaki, K

    1971-01-01

    Three strains of Escherichia coli possessing the multiple drug resistance were found to be resistant also to HgCl/sub 2/, though they were sensitive to other heavy metal ions such as nickel, cobalt, cadmium and zinc ions. Like the resistance to drugs such as chloramphenicol and tetracycline, the HgCl/sub 2/ resistance could be transferred from a resistant strain of E. coli to sensitive strains of E. coli and Aerobacter aerogenes. The resistant strains could grow in the presence of 0.02 mM HgCl/sub 2/, whereas a sensitive strain failed to grow in the presence of 0.01 mM HgCl/sub 2/. During cultivation in the presence of HgCl/sub 2/, the cells of resistant strain vaporized a form of radioactive mercury when incubated with /sup 203/HgCl/sub 2/, glucose and NaCl in phosphate buffer while the cells of sensitive strain showed no such activity. This phenomenon seemed to explain the HgCl/sub 2/ resistance of the resistant strains.

  4. Enhancement of innate immunity with granulocyte colony-stimulating factor did not mitigate disease in pigs infected with a highly pathogenic Chinese PRRSV strain.

    Science.gov (United States)

    Schlink, Sarah N; Lager, Kelly M; Brockmeier, Susan L; Loving, Crystal L; Miller, Laura C; Vorwald, Ann C; Yang, Han-Chun; Kehrli, Marcus E; Faaberg, Kay S

    2016-10-15

    Porcine reproductive and respiratory syndrome virus (PRRSV) is responsible for one of the most economically important diseases in swine worldwide. It causes reproductive failure in sows and pneumonia in pigs that predisposes them to secondary bacterial infections. Methods to control PRRSV and/or limit secondary bacterial infections are desired to reduce the impact of this virus on animal health. Neutrophils play a major role in combatting infection; they can act as phagocytes as well as produce and release lytic enzymes that have potent antimicrobial effects leading to the destruction and clearance of bacterial pathogens. Granulocyte-colony stimulating factor (G-CSF) is a cytokine that controls the production, differentiation and function of granulocytes (including neutrophils) from the bone marrow. Recent work from our laboratory has shown that encoding porcine G-CSF in a replication-defective adenovirus (Ad5-G-CSF) and delivering a single dose to pigs induced a neutrophilia lasting more than two weeks. As secondary bacterial infection is a common occurrence following PRRSV infection, particularly following challenge with highly pathogenic (HP)-PRRSV, the aim of the current study was to evaluate the effectiveness of a single prophylactic dose of adenovirus-encoded G-CSF to mitigate secondary bacterial disease associated with HP-PRRSV infection. Administration of Ad5-G-CSF induced a significant neutrophilia as expected. However, between 1 and 2days following HP-PRRSV challenge the number of circulating neutrophils decreased dramatically in the HP-PRRSV infected group, but not the non-infected Ad5-G-CSF group. Ad5-G-CSF administration induced monocytosis as well, which was also reduced by HP-PRRSV challenge. There was no difference in the progression of disease between the Ad5-G-CSF and Ad5-empty groups following HP-PRRSV challenge, with pneumonia and systemic bacterial infection occurring in both treatment groups. Given the impact of HP-PRRSV infection on the

  5. Strain compensation in InGaN-based multiple quantum wells using AlGaN interlayers

    Directory of Open Access Journals (Sweden)

    Syed Ahmed Al Muyeed

    2017-10-01

    Full Text Available Data are presented on strain compensation in InGaN-based multiple quantum wells (MQW using AlGaN interlayers (ILs. The MQWs consist of five periods of InxGa1-xN/AlyGa1-yN/GaN emitting in the green (λ ∼ 535 nm ± 15 nm, and the AlyGa1-yN IL has an Al composition of y = 0.42. The IL is varied from 0 - 2.1 nm, and the relaxation of the MQW with respect to the GaN template layer varies with IL thickness as determined by reciprocal space mapping about the (202¯5 reflection. The minimum in the relaxation occurs at an interlayer thickness of 1 nm, and the MQW is nearly pseudomorphic to GaN. Both thinner and thicker ILs display increased relaxation. Photoluminescence data shows enhanced spectral intensity and narrower full width at half maximum for the MQW with 1 nm thick ILs, which is a product of pseudomorphic layers with lower defect density and non-radiative recombination.

  6. Phenotypic and genomic comparisons of highly vancomycin-resistant Staphylococcus aureus strains developed from multiple clinical MRSA strains by in vitro mutagenesis.

    Science.gov (United States)

    Ishii, Kenichi; Tabuchi, Fumiaki; Matsuo, Miki; Tatsuno, Keita; Sato, Tomoaki; Okazaki, Mitsuhiro; Hamamoto, Hiroshi; Matsumoto, Yasuhiko; Kaito, Chikara; Aoyagi, Tetsuji; Hiramatsu, Keiichi; Kaku, Mitsuo; Moriya, Kyoji; Sekimizu, Kazuhisa

    2015-11-25

    The development of vancomycin (VCM) resistance in Staphylococcus aureus threatens global health. Studies of the VCM-resistance mechanism and alternative therapeutic strategies are urgently needed. We mutagenized S. aureus laboratory strains and methicillin-resistant S. aureus (MRSA) with ethyl methanesulfonate, and isolated mutants that exhibited high resistance to VCM (minimum inhibitory concentration = 32 μg/ml). These VCM-resistant strains were sensitive to linezolid and rifampicin, and partly to arbekacin and daptomycin. Beta-lactams had synergistic effects with VCM against these mutants. VCM-resistant strains exhibited a 2-fold increase in the cell wall thickness. Several genes were commonly mutated among the highly VCM-resistant mutants. These findings suggest that MRSA has a potential to develop high VCM resistance with cell wall thickening by the accumulation of mutations.

  7. Multiple strains probiotics appear to be the most effective probiotics in the prevention of necrotizing enterocolitis and mortality: An updated meta-analysis.

    Science.gov (United States)

    Chang, Hung-Yang; Chen, Jin-Hua; Chang, Jui-Hsing; Lin, Hung-Chih; Lin, Chien-Yu; Peng, Chun-Chih

    2017-01-01

    Some oral probiotics have been shown to prevent necrotizing enterocolitis (NEC) and decrease mortality effectively in preterm very low birth weight (PVLBW) infants. However, it is unclear whether a single probiotic or a mixture of probiotics is most effective for the prevention of NEC. A meta-analysis was conducted by reviewing the most up to date literature to investigate whether multiple strains probiotics are more effective than a single strain in reducing NEC and death in PVLBW infants. Relevant studies were identified by searches of the MEDLINE, EMBASE, and Cochrane CENTRAL databases, from 2001 to 2016. The inclusion criteria were randomized controlled trials of any enteral probiotic supplementation that was initiated within the first 7 days and continued for at least 14 days in preterm infants (≤ 34 weeks' gestation) and/or those of a birth weight ≤1500 g. A total of 25 trials (n = 7345 infants) were eligible for inclusion in the meta-analysis using a fixed-effects model. Multiple strains probiotics were associated with a marked reduction in the incidence of NEC, with a pooled OR of 0.36 (95% CI, 0.24-0.53; P probiotic using Lactobacillus species had a borderline effect in reducing NEC (OR of 0.60; 95% CI 0.36-1.0; P = .05), but not mortality. Multiple strains probiotics had a greater effectiveness in reducing mortality and were associated with a pooled OR of 0.58 (95% CI, 0.43-0.79; P = .0006). Trials using single strain of Bifidobacterium species and Saccharomyces boulardii did not reveal any beneficial effects in terms of reducing NEC or mortality. This updated report found that multiple strains probiotics appear to be the most feasible and effective strategy for the prevention of NEC and reduction of mortality in PVLBW neonates. Further clinical trials should focus on which probiotic combinations are most effective.

  8. Typing of avian pathogenic Escherichia coli strains by REP-PCR Tipificação de amostras aviárias patogênicas de Escherichia coli pela REP-PCR

    Directory of Open Access Journals (Sweden)

    Marcelo Brocchi

    2006-06-01

    Full Text Available In the present study the repetitive extragenic palindromic (REP polymerase chain reaction (PCR technique was used to establish the clonal variability of 49 avian Escherichia coli (APEC strains isolated from different outbreak cases of septicemia (n=24, swollen head syndrome (n=14 and omphalitis (n=11. Thirty commensal strains isolated from poultry with no signs of these illnesses were used as control strains. The purified DNA of these strains produced electrophoretic profiles ranging from 0 to 15 bands with molecular sizes varying from 100 bp to 6.1 kb, allowing the grouping of the 79 strains into a dendrogram containing 49 REP-types. Although REP-PCR showed good discriminating power it was not able to group the strains either into specific pathogenic classes or to differentiate between pathogenic and non-pathogenic strains. On the contrary, we recently demonstrated that other techniques such as ERIC-PCR and isoenzyme profiles are appropriate to discriminate between commensal and APEC strains and also to group these strains into specific pathogenic classes. In conclusion, REP-PCR seems to be a technique neither efficient nor universal for APEC strains discrimination. However, the population clonal structure obtained with the use of REP-PCR must not be ignored particularly if one takes into account that the APEC pathogenic mechanisms are not completely understood yet.A técnica de REP (Repetitive extragenic palindrome-PCR foi utilizada para avaliar a variabilidade genética de 49 amostras de Escherichia coli patogênicas para aves (APEC, isoladas de aves de corte (frangos em diferentes surtos de septicemia (n=24, síndrome da cabeça inchada (n=14 e onfalite (n=11. Trinta amostras comensais, isoladas de frangos sem sinais de doença, foram utilizadas como controle. A análise do perfil eletroforético obtido por reação de REP-PCR utilizando DNA purificado das amostras evidenciou a amplificação de 0 a 15 bandas de DNA com pesos moleculares

  9. Targeting multiple pathogenic mechanisms with polyphenols for the treatment of Alzheimer’s disease: Experimental approach and therapeutic implications

    Directory of Open Access Journals (Sweden)

    Jun eWang

    2014-03-01

    Full Text Available Alzheimer’s disease (AD is the most prevalent neurodegenerative disease of aging and currently has no cure. Its onset and progression are influenced by multiple factors. There is growing consensus that successful treatment will rely on simultaneously targeting multiple pathological features of AD. Polyphenol compounds have many proven health benefits. In this study, we tested the hypothesis that combining three polyphenolic preparations (grape seed extract, resveratrol and Concord grape juice extract, with different polyphenolic compositions and partially redundant bioactivities, may simultaneously and synergistically mitigate amyloid-β (Aβ mediated neuropathology and cognitive impairments in a mouse model of AD. We found that administration of the polyphenols in combination did not alter the profile of bioactive polyphenol metabolites in the brain. We also found that combination treatment resulted in better protection against cognitive impairments compared to individual treatments, in J20 AD mice. Electrophysiological examination showed that acute treatment with select brain penetrating polyphenol metabolites, derived from these polyphenols, improved oligomeric Aβ (oAβ-induced long term potentiation (LTP deficits in hippocampal slices. Moreover, we found greatly reduced total amyloid content in the brain following combination treatment. Our studies provided experimental evidence that application of polyphenols targeting multiple disease-mechanisms may yield a greater likelihood of therapeutic efficacy.

  10. A large outbreak of salmonellosis associated with sandwiches contaminated with multiple bacterial pathogens purchased via an online shopping service.

    Science.gov (United States)

    Wei, Sung-Hsi; Huang, Angela S; Liao, Ying-Shu; Liu, Yu-Lun; Chiou, Chien-Shun

    2014-03-01

    Food sold over the internet is an emerging business that also presents a concern with regard to food safety. A nationwide foodborne disease outbreak associated with sandwiches purchased from an online shop in July 2010 is reported. Consumers were telephone interviewed with a structured questionnaire and specimens were collected for etiological examination. A total of 886 consumers were successfully contacted and completed the questionnaires; 36.6% had become ill, with a median incubation period of 18 h (range, 6-66 h). The major symptoms included diarrhea (89.2%), abdominal pain (69.8%), fever (47.5%), headache (32.7%), and vomiting (17.3%). Microbiological laboratories isolated Salmonella enterica serovar Enteritidis, Salmonella Virchow, Staphylococcus aureus, Bacillus cereus, and enterotoxigenic Escherichia coli from the contaminated sandwiches, Salmonella Enteritidis and Salmonella Virchow from the patients, and Salmonella Enteritidis and Staphylococcus aureus from food handlers. Pulsed-field gel electrophoresis genotyping suggested a common origin of Salmonella bacteria recovered from the patients, food, and a food handler. Among the pathogens detected, the symptoms and incubation period indicated that Salmonella, likely of egg origin, was the probable causative agent of the outbreak. This outbreak illustrates the importance of meticulous hygiene practices during food preparation and temperature control during food shipment and the food safety challenges posed by online food-shopping services.

  11. A Large Outbreak of Salmonellosis Associated with Sandwiches Contaminated with Multiple Bacterial Pathogens Purchased via an Online Shopping Service

    Science.gov (United States)

    Wei, Sung-Hsi; Huang, Angela S.; Liao, Ying-Shu; Liu, Yu-Lun

    2014-01-01

    Abstract Food sold over the internet is an emerging business that also presents a concern with regard to food safety. A nationwide foodborne disease outbreak associated with sandwiches purchased from an online shop in July 2010 is reported. Consumers were telephone interviewed with a structured questionnaire and specimens were collected for etiological examination. A total of 886 consumers were successfully contacted and completed the questionnaires; 36.6% had become ill, with a median incubation period of 18 h (range, 6–66 h). The major symptoms included diarrhea (89.2%), abdominal pain (69.8%), fever (47.5%), headache (32.7%), and vomiting (17.3%). Microbiological laboratories isolated Salmonella enterica serovar Enteritidis, Salmonella Virchow, Staphylococcus aureus, Bacillus cereus, and enterotoxigenic Escherichia coli from the contaminated sandwiches, Salmonella Enteritidis and Salmonella Virchow from the patients, and Salmonella Enteritidis and Staphylococcus aureus from food handlers. Pulsed-field gel electrophoresis genotyping suggested a common origin of Salmonella bacteria recovered from the patients, food, and a food handler. Among the pathogens detected, the symptoms and incubation period indicated that Salmonella, likely of egg origin, was the probable causative agent of the outbreak. This outbreak illustrates the importance of meticulous hygiene practices during food preparation and temperature control during food shipment and the food safety challenges posed by online food–shopping services. PMID:24313786

  12. Modeling the growth dynamics of multiple Escherichia coli strains in the pig intestine following intramuscular ampicillin treatment

    DEFF Research Database (Denmark)

    Ahmad, Amais; Zachariasen, Camilla; Christiansen, Lasse Engbo

    2016-01-01

    using a mathematical model to simulate the competitive growth of E. coli strains in a pig intestine under specified plasma concentration profiles of ampicillin. Results : In vitro growth results demonstrated that the resistant strains did not carry a fitness cost for their resistance, and that the most...... susceptible strains were more affected by increasing concentrations of antibiotics that the rest of the strains. The modeling revealed that short treatment duration resulted in lower levels of resistance and that dosing frequency did not substantially influence the growth of resistant strains. Resistance...... with ampicillin resistance in E. coli. Besides dosing factors, epidemiological factors (such as number of competing strains and bacterial excretion) influenced resistance development and need to be considered further in relation to optimal treatment strategies. The modeling approach used in the study is generic...

  13. Comparative genomics of multidrug resistance-encoding IncA/C plasmids from commensal and pathogenic Escherichia coli from multiple animal sources.

    Science.gov (United States)

    Fernández-Alarcón, Claudia; Singer, Randall S; Johnson, Timothy J

    2011-01-01

    Incompatibility group A/C (IncA/C) plasmids have received recent attention for their broad host range and ability to confer resistance to multiple antimicrobial agents. Due to the potential spread of multidrug resistance (MDR) phenotypes from foodborne pathogens to human pathogens, the dissemination of these plasmids represents a public health risk. In this study, four animal-source IncA/C plasmids isolated from Escherichia coli were sequenced and analyzed, including isolates from commercial dairy cows, pigs and turkeys in the U.S. and Chile. These plasmids were initially selected because they either contained the floR and tetA genes encoding for florfenicol and tetracycline resistance, respectively, and/or the bla(CMY-2) gene encoding for extended spectrum β-lactamase resistance. Overall, sequence analysis revealed that each of the four plasmids retained a remarkably stable and conserved backbone sequence, with differences observed primarily within their accessory regions, which presumably have evolved via horizontal gene transfer events involving multiple modules. Comparison of these plasmids with other available IncA/C plasmid sequences further defined the core and accessory elements of these plasmids in E. coli and Salmonella. Our results suggest that the bla(CMY-2) plasmid lineage appears to have derived from an ancestral IncA/C plasmid type harboring floR-tetAR-strAB and Tn21-like accessory modules. Evidence is mounting that IncA/C plasmids are widespread among enteric bacteria of production animals and these emergent plasmids have flexibility in their acquisition of MDR-encoding modules, necessitating further study to understand the evolutionary mechanisms involved in their dissemination and stability in bacterial populations.

  14. Comparative genomics of multidrug resistance-encoding IncA/C plasmids from commensal and pathogenic Escherichia coli from multiple animal sources.

    Directory of Open Access Journals (Sweden)

    Claudia Fernández-Alarcón

    Full Text Available Incompatibility group A/C (IncA/C plasmids have received recent attention for their broad host range and ability to confer resistance to multiple antimicrobial agents. Due to the potential spread of multidrug resistance (MDR phenotypes from foodborne pathogens to human pathogens, the dissemination of these plasmids represents a public health risk. In this study, four animal-source IncA/C plasmids isolated from Escherichia coli were sequenced and analyzed, including isolates from commercial dairy cows, pigs and turkeys in the U.S. and Chile. These plasmids were initially selected because they either contained the floR and tetA genes encoding for florfenicol and tetracycline resistance, respectively, and/or the bla(CMY-2 gene encoding for extended spectrum β-lactamase resistance. Overall, sequence analysis revealed that each of the four plasmids retained a remarkably stable and conserved backbone sequence, with differences observed primarily within their accessory regions, which presumably have evolved via horizontal gene transfer events involving multiple modules. Comparison of these plasmids with other available IncA/C plasmid sequences further defined the core and accessory elements of these plasmids in E. coli and Salmonella. Our results suggest that the bla(CMY-2 plasmid lineage appears to have derived from an ancestral IncA/C plasmid type harboring floR-tetAR-strAB and Tn21-like accessory modules. Evidence is mounting that IncA/C plasmids are widespread among enteric bacteria of production animals and these emergent plasmids have flexibility in their acquisition of MDR-encoding modules, necessitating further study to understand the evolutionary mechanisms involved in their dissemination and stability in bacterial populations.

  15. Modeling the growth dynamics of multiple Escherichia coli strains in the pig intestine following intramuscular ampicillin treatment.

    Science.gov (United States)

    Ahmad, Amais; Zachariasen, Camilla; Christiansen, Lasse Engbo; Græsbøll, Kaare; Toft, Nils; Matthews, Louise; Nielsen, Søren Saxmose; Olsen, John Elmerdahl

    2016-09-06

    This study evaluated how dosing regimen for intramuscularly-administered ampicillin, composition of Escherichia coli strains with regard to ampicillin susceptibility, and excretion of bacteria from the intestine affected the level of resistance among Escherichia coli strains in the intestine of nursery pigs. It also examined the dynamics of the composition of bacterial strains during and after the treatment. The growth responses of strains to ampicillin concentrations were determined using in vitro growth curves. Using these results as input data, growth predictions were generated using a mathematical model to simulate the competitive growth of E. coli strains in a pig intestine under specified plasma concentration profiles of ampicillin. In vitro growth results demonstrated that the resistant strains did not carry a fitness cost for their resistance, and that the most susceptible strains were more affected by increasing concentrations of antibiotics that the rest of the strains. The modeling revealed that short treatment duration resulted in lower levels of resistance and that dosing frequency did not substantially influence the growth of resistant strains. Resistance levels were found to be sensitive to the number of competing strains, and this effect was enhanced by longer duration of treatment. High excretion of bacteria from the intestine favored resistant strains over sensitive strains, but at the same time it resulted in a faster return to pre-treatment levels after the treatment ended. When the duration of high excretion was set to be limited to the treatment time (i.e. the treatment was assumed to result in a cure of diarrhea) resistant strains required longer time to reach the previous level. No fitness cost was found to be associated with ampicillin resistance in E. coli. Besides dosing factors, epidemiological factors (such as number of competing strains and bacterial excretion) influenced resistance development and need to be considered further in

  16. Modeling the growth dynamics of multiple Escherichia coli strains in the pig intestine following intramuscular ampicillin treatment

    DEFF Research Database (Denmark)

    Ahmad, Amais; Zachariasen, Camilla; Christiansen, Lasse Engbo

    2016-01-01

    using a mathematical model to simulate the competitive growth of E. coli strains in a pig intestine under specified plasma concentration profiles of ampicillin. Results : In vitro growth results demonstrated that the resistant strains did not carry a fitness cost for their resistance, and that the most...... with ampicillin resistance in E. coli. Besides dosing factors, epidemiological factors (such as number of competing strains and bacterial excretion) influenced resistance development and need to be considered further in relation to optimal treatment strategies. The modeling approach used in the study is generic......Background : This study evaluated how dosing regimen for intramuscularly-administered ampicillin, composition of Escherichia coli strains with regard to ampicillin susceptibility, and excretion of bacteria from the intestine affected the level of resistance among Escherichia coli strains...

  17. A gene encoding maize caffeoyl-CoA O-methyltransferase confers quantitative resistance to multiple pathogens.

    Science.gov (United States)

    Yang, Qin; He, Yijian; Kabahuma, Mercy; Chaya, Timothy; Kelly, Amy; Borrego, Eli; Bian, Yang; El Kasmi, Farid; Yang, Li; Teixeira, Paulo; Kolkman, Judith; Nelson, Rebecca; Kolomiets, Michael; L Dangl, Jeffery; Wisser, Randall; Caplan, Jeffrey; Li, Xu; Lauter, Nick; Balint-Kurti, Peter

    2017-09-01

    Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement, although the molecular mechanisms underlying their functions remain largely unknown. A quantitative trait locus, qMdr 9.02 , associated with resistance to three important foliar maize diseases-southern leaf blight, gray leaf spot and northern leaf blight-has been identified on maize chromosome 9. Through fine-mapping, association analysis, expression analysis, insertional mutagenesis and transgenic validation, we demonstrate that ZmCCoAOMT2, which encodes a caffeoyl-CoA O-methyltransferase associated with the phenylpropanoid pathway and lignin production, is the gene within qMdr 9.02 conferring quantitative resistance to both southern leaf blight and gray leaf spot. We suggest that resistance might be caused by allelic variation at the level of both gene expression and amino acid sequence, thus resulting in differences in levels of lignin and other metabolites of the phenylpropanoid pathway and regulation of programmed cell death.

  18. Draft Genome Sequences of Three Escherichia coli Strains with Different In Vivo Pathogenicities in an Avian (Ascending) Infection Model of the Oviduct.

    Science.gov (United States)

    Olsen, Rikke Heidemann; Thøfner, Ida Cecilie Naundrup; Pors, Susanne Elisabeth; Christensen, Henrik; Bisgaard, Magne; Christensen, Jens Peter

    2015-05-07

    Here, we present three draft genome sequences of Escherichia coli strains that experimentally were proven to possess low (strain D2-2), intermediate (Chronic_salp), or high virulence (Cp6salp3) in an avian (ascending) infection model of the oviduct. Copyright © 2015 Olsen et al.

  19. Molecular characterization of a human G20P[28] rotavirus a strain with multiple genes related to bat rotaviruses.

    Science.gov (United States)

    Esona, Mathew D; Roy, Sunando; Rungsrisuriyachai, Kunchala; Gautam, Rashi; Hermelijn, Sandra; Rey-Benito, Gloria; Bowen, Michael D

    2018-01-01

    Group A rotaviruses are the major cause of severe gastroenteritis in the young of mammals and birds. This report describes characterization of an unusual G20P[28] rotavirus strain detected in a 24month old child from Suriname. Genomic sequence analyses revealed that the genotype constellation of the Suriname strain RVA/Human-wt/SUR/2014735512/2013/G20P[28] was G20-P[28]-I13-R13-C13-M12-A23-N13-T15-E20-H15. Genes VP1, VP2, VP3, NSP1, NSP2, NSP3, NSP4 and NSP5 were recently assigned novel genotypes by the Rotavirus Classification Working Group (RCWG). Three of the 11 gene segments (VP7, VP4, VP6) were similar to cognate gene sequences of bat-like human rotavirus strain Ecu534 from Ecuador and the VP7, NSP3 and NSP5 gene segments of strain RVA/Human-wt/SUR/2014735512/2013/G20P[28] were found to be closely related to gene sequences of bat rotavirus strain 3081/BRA detected in Brazil. Although distantly related, the VP1 gene of the study strain and bat strain BatLi09 detected in Cameroon in 2014 are monophyletic. The NSP1 gene was found to be most closely related to human strain QUI-35-F5 from Brazil. These findings suggest that strain RVA/Human-wt/SUR/2014735512/2013/G20P[28] represents a zoonotic infection from a bat host. Published by Elsevier B.V.

  20. The effect of interactions between a bacterial strain isolated from drinking water and a pathogen surrogate on biofilms formation diverged under static vs flow conditions.

    Science.gov (United States)

    Dai, D; Raskin, L; Xi, C

    2017-12-01

    Interactions with water bacteria affect the incorporation of pathogens into biofilms and thus pathogen control in drinking water systems. This study was to examine the impact of static vs flow conditions on interactions between a pathogen and a water bacterium on pathogen biofilm formation under laboratory settings. A pathogen surrogate Escherichia coli and a drinking water isolate Stenotrophomonas maltophilia was selected for this study. Biofilm growth was examined under two distinct conditions, in flow cells with continuous medium supply vs in static microtitre plates with batch culture. E. coli biofilm was greatly stimulated (c. 2-1000 times faster) with the presence of S. maltophilia in flow cells, but surprisingly inhibited (c. 65-95% less biomass) in microtitre plates. These divergent effects were explained through various aspects including surface attachment, cellular growth, extracellular signals and autoaggregation. Interactions with the same water bacterium resulted in different effects on E. coli biofilm formation when culture conditions changed from static to flow. This study highlights the complexity of species interactions on biofilm formation and suggests that environmental conditions such as the flow regime can be taken into consideration for the management of microbial contamination in drinking water systems. © 2017 The Society for Applied Microbiology.

  1. Rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae produces multiple DSF-family signals in regulation of virulence factor production

    Directory of Open Access Journals (Sweden)

    Cha Jae-Soon

    2010-07-01

    Full Text Available Abstract Background Xanthomonas oryzae pv. oryzae (Xoo is the causal agent of rice bacterial blight disease. Xoo produces a range of virulence factors, including EPS, extracellular enzyme, iron-chelating siderophores, and type III-secretion dependent effectors, which are collectively essential for virulence. Genetic and genomics evidence suggest that Xoo might use the diffusible signal factor (DSF type quorum sensing (QS system to regulate the virulence factor production. However, little is known about the chemical structure of the DSF-like signal(s produced by Xoo and the factors influencing the signal production. Results Xoo genome harbours an rpf cluster comprising rpfB, rpfF, rpfC and rpfG. The proteins encoded by these genes are highly homologous to their counterparts in X. campestris pv. campestris (Xcc, suggesting that Xcc and Xoo might use similar mechanisms for DSF biosynthesis and autoregulation. Consistent with in silico analysis, the rpfF mutant was DSF-deficient and the rpfC mutant produced about 25 times higher DSF-like activity than the wild type Xoo strain KACC10331. From the supernatants of rpfC mutant, we purified three compounds showing strong DSF-like activity. Mass spectrometry and NMR analysis revealed that two of them were the previously characterized DSF and BDSF; the third one was a novel unsaturated fatty acid with 2 double bonds and was designated as CDSF in this study. Further analysis showed that all the three DSF-family signals were synthesized via the enzyme RpfF encoded by Xoo2868. DSF and BDSF at a final concentration of 3 μM to the rpfF mutant could fully restore its extracellular xylanase activity and EPS production to the wild type level, but CDSF was less active than DSF and BDSF in induction of EPS and xylanase. DSF and CDSF shared a similar cell density-dependent production time course with the maximum production being detected at 42 h after inoculation, whereas the maximum production of BDSF was observed

  2. Observation and quantification of water penetration into Strain Hardening Cement-based Composites (SHCC) with multiple cracks by means of neutron radiography

    International Nuclear Information System (INIS)

    Zhang, P.; Wittmann, F.H.; Zhao, T.J.; Lehmann, E.H.; Tian, L.; Vontobel, P.

    2010-01-01

    Durability of reinforced concrete structures has become a crucial issue with respect to economy, ecology and sustainability. One major reason for durability problems of concrete structures is the limited strain capacity of cement-based materials under imposed tensile stress. By adding PVA fibers, a new material named Strain Hardening Cement-based Composites (SHCC) with high strain capacity can be produced. Due to the formation of multiple micro-cracks, wide cracks can be avoided in SHCC under an imposed strain. The high strain capacity, however, is beneficial with respect to durability only if the multi-crack formation in SHCC does not lead to significantly increased water penetration. If water and aggressive chemical compounds such as chlorides and sulfates dissolved in water penetrate into the cement-based matrix and reach the steel reinforcement service-life of reinforced concrete structures will be reduced significantly. In this project, neutron radiography was applied to observe and quantify the process of water penetration into uncracked SHCC and after the multi-crack formation. In addition, water penetration into integral water repellent cracked and uncracked SHCC, which has been produced by adding a silane-based water repellent agent to the fresh SHCC mortar has been investigated. Results will be discussed with respect to durability.

  3. The Prenylflavonoid Xanthohumol Reduces Alzheimer-Like Changes and Modulates Multiple Pathogenic Molecular Pathways in the Neuro2a/APPswe Cell Model of AD

    Directory of Open Access Journals (Sweden)

    Xianfeng Huang

    2018-04-01

    Full Text Available Alzheimer’s disease (AD is a progressive neurodegenerative disorder that has proved refractory to drug treatment. Given evidence of neuroprotection in animal models of ischemic stroke, we assessed the prenylflavonoid xanthohumol from the Common Hop (Humulus lupulus L. for therapeutic potential in murine neuroblastoma N2a cells stably expressing human Swedish mutant amyloid precursor protein (N2a/APP, a well-characterized cellular model of AD. The ELISA and Western-blot analysis revealed that xanthohumol (Xn inhibited Aβ accumulation and APP processing, and that Xn ameliorated tau hyperphosphorylation via PP2A, GSK3β pathways in N2a/APP cells. The amelioration of tau hyperphosphorylation by Xn was also validated on HEK293/Tau cells, another cell line with tau hyperphosphorylation. Proteomic analysis (2D-DIGE-coupled MS revealed a total of 30 differentially expressed lysate proteins in N2a/APP vs. wild-type (WT N2a cells (N2a/WT, and a total of 21 differentially expressed proteins in lysates of N2a/APP cells in the presence or absence of Xn. Generally, these 51 differential proteins could be classified into seven main categories according to their functions, including: endoplasmic reticulum (ER stress-associated proteins; oxidative stress-associated proteins; proteasome-associated proteins; ATPase and metabolism-associated proteins; cytoskeleton-associated proteins; molecular chaperones-associated proteins, and others. We used Western-blot analysis to validate Xn-associated changes of some key proteins in several biological/pathogenic processes. Taken together, we show that Xn reduces AD-related changes in stably transfected N2a/APP cells. The underlying mechanisms involve modulation of multiple pathogenic pathways, including those involved in ER stress, oxidative stress, proteasome molecular systems, and the neuronal cytoskeleton. These results suggest Xn may have potential for the treatment of AD and/or neuropathologically related

  4. Use of bacillus subtilis strains to inhibit postharvest pathogenic fungi; Attivita` antagonista di alcuni ceppi di bacillus subtilis nei confronti di funghi patogeni

    Energy Technology Data Exchange (ETDEWEB)

    Arras, G.; Gambella, F.; Demontis, S.; Petretto, A.

    1995-09-01

    An isolate (87) of the bacillus subtilis strains isolated from cold stored citrus fruit 13 proved to inhibit the growth in vitro of the penicillium italicum used in the experiment (from 50.6% to 92.2%) and to inhibit botrytis cinerea (from 65.3% to 95.9%). A further test, superimposing on plates containing PDA strains Nos. 13, 173, and 160, totally inhibited the fungi. Tested in vivo on artificially bruised oranges, they significantly inhibited two fungi.

  5. Effect of helium-neon laser radiation on conventionally - pathogenous microorganisms

    International Nuclear Information System (INIS)

    Shesterina, M.V.; Kalyuk, A.N.; Maliev, B.M.

    1987-01-01

    Results are reported of single and multiple irradiation with low-energy helium-neon lasers (different doses and regimens) on growth and properties of conventionally-pathogenous microflora isolated from patients with pulmonary tuberculosis and cultures of standard microorganisms. The above mentioned laser radiation produced an inhibitory effect on some strains of conventionally-pathogenous microflora manifested in inhibition of the growth properties of cultures as the energy dose increased

  6. Development of an allele-specific PCR assay for simultaneous sero-typing of avian pathogenic Escherichia coli predominant O1, O2, O18 and O78 strains.

    Science.gov (United States)

    Wang, Shaohui; Meng, Qingmei; Dai, Jianjun; Han, Xiangan; Han, Yue; Ding, Chan; Liu, Haiwen; Yu, Shengqing

    2014-01-01

    Systemic infections by avian pathogenic Escherichia coli (APEC) are economically devastating to poultry industries worldwide. E. coli strains belonging to serotypes O1, O2, O18 and O78 are preferentially associated with avian colibacillosis. The rfb gene cluster controlling O antigen synthesis is usually various among different E. coli serotypes. In present study, the rfb gene clusters of E. coli serotypes O1, O2, O18 and O78 were characterized and compared. Based on the serotype-specific genes in rfb gene cluster, an allele-specific polymerase chain reaction (PCR) assay was developed. This PCR assay was highly specific and reliable for sero-typing of APEC O1, O2, O18 and O78 strains. The sensitivity of the assay was determined as 10 pg DNA or 10 colony forming units (CFUs) bacteria for serotypes O2 and O18 strains, and 500 pg DNA or 1,000 CFUs bacteria for serotypes O1 and O78 strains. Using this PCR system, APEC isolates and the infected tissue samples were categorized successfully. Furthermore, it was able to differentiate the serotypes for the samples with multi-agglutination in the traditional serum agglutination assay. Therefore, the allele-specific PCR is more simple, rapid and accurate assay for APEC diagnosis, epidemiologic study and vaccine development.

  7. Development of an allele-specific PCR assay for simultaneous sero-typing of avian pathogenic Escherichia coli predominant O1, O2, O18 and O78 strains.

    Directory of Open Access Journals (Sweden)

    Shaohui Wang

    Full Text Available Systemic infections by avian pathogenic Escherichia coli (APEC are economically devastating to poultry industries worldwide. E. coli strains belonging to serotypes O1, O2, O18 and O78 are preferentially associated with avian colibacillosis. The rfb gene cluster controlling O antigen synthesis is usually various among different E. coli serotypes. In present study, the rfb gene clusters of E. coli serotypes O1, O2, O18 and O78 were characterized and compared. Based on the serotype-specific genes in rfb gene cluster, an allele-specific polymerase chain reaction (PCR assay was developed. This PCR assay was highly specific and reliable for sero-typing of APEC O1, O2, O18 and O78 strains. The sensitivity of the assay was determined as 10 pg DNA or 10 colony forming units (CFUs bacteria for serotypes O2 and O18 strains, and 500 pg DNA or 1,000 CFUs bacteria for serotypes O1 and O78 strains. Using this PCR system, APEC isolates and the infected tissue samples were categorized successfully. Furthermore, it was able to differentiate the serotypes for the samples with multi-agglutination in the traditional serum agglutination assay. Therefore, the allele-specific PCR is more simple, rapid and accurate assay for APEC diagnosis, epidemiologic study and vaccine development.

  8. Airborne transmission of a highly pathogenic avian influenza strain H5N1 between groups of chickens quantified in an experimental setting.

    NARCIS (Netherlands)

    Spekreijse, D.; Bouma, A.; Koch, G.; Stegeman, J.A.

    2011-01-01

    Highly pathogenic avian influenza (HPAI) is a devastating viral disease of poultry and quick control of outbreaks is vital. Airborne transmission has often been suggested as a route of transmission between flocks, but knowledge of the rate of transmission via this route is sparse. In the current

  9. The complete and fully assembled genome sequence of Aeromonas salmonicida subsp. pectinolytica and its comparative analysis with other Aeromonas species: investigation of the mobilome in environmental and pathogenic strains.

    Science.gov (United States)

    Pfeiffer, Friedhelm; Zamora-Lagos, Maria-Antonia; Blettinger, Martin; Yeroslaviz, Assa; Dahl, Andreas; Gruber, Stephan; Habermann, Bianca H

    2018-01-05

    Due to the predominant usage of short-read sequencing to date, most bacterial genome sequences reported in the last years remain at the draft level. This precludes certain types of analyses, such as the in-depth analysis of genome plasticity. Here we report the finalized genome sequence of the environmental strain Aeromonas salmonicida subsp. pectinolytica 34mel, for which only a draft genome with 253 contigs is currently available. Successful completion of the transposon-rich genome critically depended on the PacBio long read sequencing technology. Using finalized genome sequences of A. salmonicida subsp. pectinolytica and other Aeromonads, we report the detailed analysis of the transposon composition of these bacterial species. Mobilome evolution is exemplified by a complex transposon, which has shifted from pathogenicity-related to environmental-related gene content in A. salmonicida subsp. pectinolytica 34mel. Obtaining the complete, circular genome of A. salmonicida subsp. pectinolytica allowed us to perform an in-depth analysis of its mobilome. We demonstrate the mobilome-dependent evolution of this strain's genetic profile from pathogenic to environmental.

  10. Antagonistic Activities of Bacillus spp. Strains Isolated from Tidal Flat Sediment Towards Anthracnose Pathogens Colletotrichum acutatum and C. gloeosporioides in South Korea.

    Science.gov (United States)

    Han, Joon-Hee; Shim, Hongsik; Shin, Jong-Hwan; Kim, Kyoung Su

    2015-06-01

    Anthracnose is a fungal disease caused by Colletotrichum species that is detrimental to numerous plant species. Anthracnose control with fungicides has both human health and environmental safety implications. Despite increasing public concerns, fungicide use will continue in the absence of viable alternatives. There have been relatively less efforts to search antagonistic bacteria from mudflats harboring microbial diversity. A total of 420 bacterial strains were isolated from mudflats near the western sea of South Korea. Five bacterial strains, LB01, LB14, HM03, HM17, and LB15, were characterized as having antifungal properties in the presence of C. acutatum and C. gloeosporioides. The three Bacillus atrophaeus strains, LB14, HM03, and HM17, produced large quantities of chitinase and protease enzymes, whereas the B. amyloliquefaciens strain LB01 produced protease and cellulase enzymes. Two important antagonistic traits, siderophore production and solubilization of insoluble phosphate, were observed in the three B. atrophaeus strains. Analyses of disease suppression revealed that LB14 was most effective for suppressing the incidence of anthracnose symptoms on pepper fruits. LB14 produced antagonistic compounds and suppressed conidial germination of C. acutatum and C. gloeosporioides. The results from the present study will provide a basis for developing a reliable alternative to fungicides for anthracnose control.

  11. Antagonistic Activities of Bacillus spp. Strains Isolated from Tidal Flat Sediment Towards Anthracnose Pathogens Colletotrichum acutatum and C. gloeosporioides in South Korea

    Directory of Open Access Journals (Sweden)

    Joon-Hee Han

    2015-06-01

    Full Text Available Anthracnose is a fungal disease caused by Colletotrichum species that is detrimental to numerous plant species. Anthracnose control with fungicides has both human health and environmental safety implications. Despite increasing public concerns, fungicide use will continue in the absence of viable alternatives. There have been relatively less efforts to search antagonistic bacteria from mudflats harboring microbial diversity. A total of 420 bacterial strains were isolated from mudflats near the western sea of South Korea. Five bacterial strains, LB01, LB14, HM03, HM17, and LB15, were characterized as having antifungal properties in the presence of C. acutatum and C. gloeosporioides. The three Bacillus atrophaeus strains, LB14, HM03, and HM17, produced large quantities of chitinase and protease enzymes, whereas the B. amyloliquefaciens strain LB01 produced protease and cellulase enzymes. Two important antagonistic traits, siderophore production and solubilization of insoluble phosphate, were observed in the three B. atrophaeus strains. Analyses of disease suppression revealed that LB14 was most effective for suppressing the incidence of anthracnose symptoms on pepper fruits. LB14 produced antagonistic compounds and suppressed conidial germination of C. acutatum and C. gloeosporioides. The results from the present study will provide a basis for developing a reliable alternative to fungicides for anthracnose control.

  12. Preliminary data on antibacterial activity of Echinacea purpurea-associated bacterial communities against Burkholderia cepacia complex strains, opportunistic pathogens of Cystic Fibrosis patients.

    Science.gov (United States)

    Chiellini, Carolina; Maida, Isabel; Maggini, Valentina; Bosi, Emanuele; Mocali, Stefano; Emiliani, Giovanni; Perrin, Elena; Firenzuoli, Fabio; Mengoni, Alessio; Fani, Renato

    2017-03-01

    Burkholderia cepacia complex bacteria (Bcc) represent a serious threat for immune-compromised patient affected by Cystic Fibrosis (CF) since they are resistant to many substances and to most antibiotics. For this reason, the research of new natural compounds able to inhibit the growth of Bcc strains has raised new interest during the last years. A source of such natural compounds is represented by medicinal plants and, in particular, by bacterial communities associated with these plants able to produce molecules with antimicrobial activity. In this work, a panel of 151 (endophytic) bacteria isolated from three different compartments (rhizospheric soil, roots, and stem/leaves) of the medicinal plant Echinacea purpurea were tested (using the cross-streak method) for their ability to inhibit the growth of 10 Bcc strains. Data obtained revealed that bacteria isolated from the roots of E. purpurea are the most active in the inhibition of Bcc strains, followed by bacteria isolated from the rhizospheric soil, and endophytes from stem/leaf compartment. At the same time, Bcc strains of environmental origin showed a higher resistance toward inhibition than the Bcc strains with clinical (i.e. CF patients) origin. Differences in the inhibition activity of E. purpurea-associated bacteria are mainly linked to the environment -the plant compartment- rather than to their taxonomical position. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Genetic Variability of the Heme Uptake System among Different Strains of the Fish Pathogen Vibrio anguillarum: Identification of a New Heme Receptor

    Science.gov (United States)

    Mouriño, Susana; Rodríguez-Ares, Isabel; Osorio, Carlos R.; Lemos, Manuel L.

    2005-01-01

    The ability to utilize heme compounds as iron sources was investigated in Vibrio anguillarum strains belonging to serotypes O1 to O10. All strains, regardless of their serotype or isolation origin could utilize hemin and hemoglobin as sole iron sources. Similarly, all of the isolates could bind hemin and Congo red, and this binding was mediated by cell envelope proteins. PCR and Southern hybridization were used to assay the occurrence of heme transport genes huvABCD, which have been previously described in serotype O1. Of 23 strains studied, two serotype O3 isolates proved negative for all huvABCD genes, whereas nine strains included in serotypes O2, O3, O4, O6, O7, and O10 tested negative for the outer membrane heme receptor gene huvA. A gene coding for a novel outer membrane heme receptor was cloned and characterized in a V. anguillarum serotype O3 strain lacking huvA. The new heme receptor, named HuvS, showed significant similarity to other outer membrane heme receptors described in Vibrionaceae, but little homology (39%) to HuvA. This heme receptor was present in 9 out of 11 of the V. anguillarum strains that tested negative for HuvA. Furthermore, complementation experiments demonstrated that HuvS could substitute for the HuvA function in Escherichia coli and V. anguillarum mutants. The huvS and huvA sequences alignment, as well as the analysis of their respective upstream and downstream DNA sequences, suggest that horizontal transfer and recombination might be responsible for generating this genetic diversity. PMID:16332832

  14. Genome sequence of "Candidatus Mycoplasma haemolamae" strain purdue, a red blood cell pathogen of alpacas (Vicugna pacos) and llamas (Lama glama).

    Science.gov (United States)

    Guimaraes, Ana M S; Toth, Balazs; Santos, Andrea P; do Nascimento, Naíla C; Kritchevsky, Janice E; Messick, Joanne B

    2012-11-01

    We report the complete genome sequence of "Candidatus Mycoplasma haemolamae," an endemic red-cell pathogen of camelids. The single, circular chromosome has 756,845 bp, a 39.3% G+C content, and 925 coding sequences (CDSs). A great proportion (49.1%) of these CDSs are organized into paralogous gene families, which can now be further explored with regard to antigenic variation.

  15. Genome Sequence of “Candidatus Mycoplasma haemolamae” Strain Purdue, a Red Blood Cell Pathogen of Alpacas (Vicugna pacos) and Llamas (Lama glama)

    OpenAIRE

    Guimaraes, Ana M. S.; Toth, Balazs; Santos, Andrea P.; do Nascimento, Naíla C.; Kritchevsky, Janice E.; Messick, Joanne B.

    2012-01-01

    We report the complete genome sequence of “Candidatus Mycoplasma haemolamae,” an endemic red-cell pathogen of camelids. The single, circular chromosome has 756,845 bp, a 39.3% G+C content, and 925 coding sequences (CDSs). A great proportion (49.1%) of these CDSs are organized into paralogous gene families, which can now be further explored with regard to antigenic variation.

  16. Genome Sequence of “Candidatus Mycoplasma haemolamae” Strain Purdue, a Red Blood Cell Pathogen of Alpacas (Vicugna pacos) and Llamas (Lama glama)

    Science.gov (United States)

    Toth, Balazs; Santos, Andrea P.; do Nascimento, Naíla C.; Kritchevsky, Janice E.

    2012-01-01

    We report the complete genome sequence of “Candidatus Mycoplasma haemolamae,” an endemic red-cell pathogen of camelids. The single, circular chromosome has 756,845 bp, a 39.3% G+C content, and 925 coding sequences (CDSs). A great proportion (49.1%) of these CDSs are organized into paralogous gene families, which can now be further explored with regard to antigenic variation. PMID:23105057

  17. Data from: Rapid multiple-level coevolution in experimental populations of yeast killer and non-killer strains

    NARCIS (Netherlands)

    Pieczynska, M.D.; Wloch-Salamon, D.; Korona, R.; Visser, de J.A.G.M.

    2016-01-01

    Coevolution between different biological entities is considered an important evolutionary mechanism at all levels of biological organization. Here we provide evidence for coevolution of a yeast killer strain (K) carrying cytoplasmic dsRNA viruses coding for anti-competitor toxins and an isogenic

  18. Co-existence of Blau syndrome and NAID? Diagnostic challenges associated with presence of multiple pathogenic variants in NOD2 gene: a case report.

    Science.gov (United States)

    Dziedzic, Magdalena; Marjańska, Agata; Bąbol-Pokora, Katarzyna; Urbańczyk, Anna; Grześk, Elżbieta; Młynarski, Wojciech; Kołtan, Sylwia

    2017-07-27

    Pediatric autoinflammatory diseases are rare and still poorly understood conditions resulting from defective genetic control of innate immune system, inter alia from anomalies of NOD2 gene. The product of this gene is Nod2 protein, taking part in maintenance of immune homeostasis. Clinical form of resultant autoinflammatory condition depends on NOD2 genotype; usually patients with NOD2 defects present with Blau syndrome, NOD2-associated autoinflammatory disease (NAID) or Crohn's disease. We present the case of a 7-year-old girl with co-existing symptoms of two rare diseases, Blau syndrome and NAID. Overlapping manifestations of two syndromes raised a significant diagnostic challenge, until next-generation molecular test (NGS) identified presence of three pathogenic variants of NOD2 gene: P268S, IVS8 +158 , 1007 fs, and established the ultimate diagnosis. Presence of multiple genetical abnormalities resulted in an ambiguous clinical presentation with overlapping symptoms of Blau syndrome and NAID. Final diagnosis of autoinflammatory disease opened new therapeutic possibilities, including the use of biological treatments.

  19. Antimicrobial multiple resistance index, minimum inhibitory concentrations, and extended-spectrum beta-lactamase producers of Proteus mirabilis and Proteus vulgaris strains isolated from domestic animals with various clinical manifestations of infection

    Directory of Open Access Journals (Sweden)

    Vanessa Zappa

    2017-05-01

    Full Text Available Proteus spp. are opportunistic multidrug resistant enterobacteria associated with diverse clinical diseases in domestic animals. However, Proteus infections in domestic animals are often misdiagnosed or considered contaminants in microbiological cultures rather than a primary agent of disease. Descriptions of Proteus infections in domestic animals are typically restricted to case reports, retrospective studies, or surveillance of other microorganisms. The present study investigated multiple antibiotic resistance indices, minimum inhibitory concentrations (MICs, and ESBL production in 73 strains of Proteus mirabilis (n = 69 and Proteus vulgaris (n = 4 isolated from domestic animals with various clinical manifestations. In dogs, the pathogen was most commonly associated with cystitis (48.21, enteritis (21.42%, otitis (14.29%, and conjunctivitis (3.57%. In bovines, the microorganism was predominant in cases of enteritis (22.22%, abscess (11.11%, otitis (11.11%, omphalitis (11.11%, and peritonitis (11.11%, and in organ fragments (11.11%. In equines (50.0% and cats (100.0%, diarrhea was the main clinical sign. In vitro standard disk diffusion assay showed that the most effective antimicrobials against the isolates were imipenem (98.63, norfloxacin (95.89, amikacin (95.89, levofloxacin (90.41, ceftriaxone (87.64, and florfenicol (87.67. In contrast, the isolates commonly showed resistance to novobiocin (95.89, azithromycin (57.53, and trimethropim/sulfamethoxazole (39.73. Among the 73 isolates, the efficacy of amoxicillin/clavulanic acid, gentamicin, ceftriaxone, and ciprofloxacin according to MICs was 87.67%, 86.30%, 84.93%, and 82.19%, respectively. The MIC50 values of amoxicillin/clavulanic acid, ceftriaxone, ciprofloxacin, and gentamicin were, respectively, 1.0, 0.004, 0.03, and 1.0 µg/mL. Thirty-three strains (45.21% showed a antimicrobial multiple resistance index of ? 0.3. Multidrug resistance profiles of isolates were observed most frequently

  20. Hormone-induced protection against mammary tumorigenesis is conserved in multiple rat strains and identifies a core gene expression signature induced by pregnancy.

    Science.gov (United States)

    Blakely, Collin M; Stoddard, Alexander J; Belka, George K; Dugan, Katherine D; Notarfrancesco, Kathleen L; Moody, Susan E; D'Cruz, Celina M; Chodosh, Lewis A

    2006-06-15

    Women who have their first child early in life have a substantially lower lifetime risk of breast cancer. The mechanism for this is unknown. Similar to humans, rats exhibit parity-induced protection against mammary tumorigenesis. To explore the basis for this phenomenon, we identified persistent pregnancy-induced changes in mammary gene expression that are tightly associated with protection against tumorigenesis in multiple inbred rat strains. Four inbred rat strains that exhibit marked differences in their intrinsic susceptibilities to carcinogen-induced mammary tumorigenesis were each shown to display significant protection against methylnitrosourea-induced mammary tumorigenesis following treatment with pregnancy levels of estradiol and progesterone. Microarray expression profiling of parous and nulliparous mammary tissue from these four strains yielded a common 70-gene signature. Examination of the genes constituting this signature implicated alterations in transforming growth factor-beta signaling, the extracellular matrix, amphiregulin expression, and the growth hormone/insulin-like growth factor I axis in pregnancy-induced alterations in breast cancer risk. Notably, related molecular changes have been associated with decreased mammographic density, which itself is strongly associated with decreased breast cancer risk. Our findings show that hormone-induced protection against mammary tumorigenesis is widely conserved among divergent rat strains and define a gene expression signature that is tightly correlated with reduced mammary tumor susceptibility as a consequence of a normal developmental event. Given the conservation of this signature, these pathways may contribute to pregnancy-induced protection against breast cancer.

  1. Fatty Acid Methyl Ester (FAME) analyses for characterization and detection of grapevine pathogens

    Science.gov (United States)

    Grapevines can become infected by a variety of devastating pathogens, including the bacterium Xylella fastidiosa and canker fungi. Multiple strains of Xylella fastidiosa exist, each causing different diseases on various hosts. Although sequence-based genotyping can assist in distinguishing these str...

  2. Comparative pathogenicity study of ten different betanodavirus strains in experimentally infected European sea bass, Dicentrarchus labrax (L.)

    DEFF Research Database (Denmark)

    Vendramin, Niccolò; Toffan, A.; Mancin, M.

    2014-01-01

    nervous necrosis virus (SJNNV), tiger puffer nervous necrosis virus and barfin flounder nervous necrosis virus, with the RGNNV genotype appearing as the most widespread in the Mediterranean region, although SJNNV-type strains and reassortant viruses have also been reported. The existence...

  3. The pan-genome of the animal pathogen Corynebacterium pseudotuberculosis reveals differences in genome plasticity between the biovar ovis and equi strains

    DEFF Research Database (Denmark)

    Soares, Siomar C; Silva, Artur; Trost, Eva

    2013-01-01

    , Corynebacterium pseudotuberculosis infections pose a rising worldwide economic problem in ruminants. The complete genome sequences of 15 C. pseudotuberculosis strains isolated from different hosts and countries were comparatively analyzed using a pan-genomic strategy. Phylogenomic, pan-genomic, core genomic...

  4. Comparative genome analysis of an avirulent and two virulent strains of avian Pasteurella multocida reveals candidate genes involved in fitness and pathogenicity

    Science.gov (United States)

    Fowl cholera is a highly contagious systemic disease affecting wild and domestic birds, frequently resulting in high morbidity and mortality. The causative agent is Pasteurella multocida (P. multocida). The completed genome of P. multocida strain Pm70 has been available for over eleven years and has...

  5. Draft genome sequences of clostridium perfringens strain LLY_N11, a pathogenic isolate of necrotic enteritis from a healthy chicken

    Science.gov (United States)

    Clostridium perfringens strain LLY_N11 is a commensal bacterial isolate from a healthy chicken that produced a necrotic enteritis in experimental studies. Here we present the assembly and annotation of its genome, which may provide further insights into improved understanding of the molecular mechan...

  6. Challenge pools of hepatitis C virus genotypes 1-6 prototype strains: replication fitness and pathogenicity in chimpanzees and human liver-chimeric mouse models

    DEFF Research Database (Denmark)

    Bukh, Jens; Meuleman, Philip; Tellier, Raymond

    2010-01-01

    Chimpanzees represent the only animal model for studies of the natural history of hepatitis C virus (HCV). To generate virus stocks of important HCV variants, we infected chimpanzees with HCV strains of genotypes 1-6 and determined the infectivity titer of acute-phase plasma pools in additional a...

  7. Over-expression of multiple cytochrome P450 genes in fenvalerate-resistant field strains of Helicoverpa armigera from north of China.

    Science.gov (United States)

    Xu, Li; Li, Dongzhi; Qin, Jianying; Zhao, Weisong; Qiu, Lihong

    2016-09-01

    Pyrethroid resistance was one of the main reasons for control failure of cotton bollworm Helicoverpa armigera (Hübner) in China. The promotion of Bt crops decreased the application of chemical insecticides in controlling H.armigera. However, the cotton bollworm still kept high levels of resistance to fenvalerate. In this study, the resistance levels of 8 field-collected strains of H. armigera from north of China to 4 insecticides, as well as the expression levels of related P450 genes were investigated. The results of bioassay indicated that the resistance levels to fenvalerate in the field strains varied from 5.4- to 114.7-fold, while the resistance levels to lambda-cyhalothrin, phoxim and methomyl were low, which were ranged from 1.5- to 5.2-, 0.2- to 1.6-, and 2.9- to 8.3- fold, respectively, compared to a susceptible strain. Synergistic experiment showed that PBO was the most effective synergist in increasing the sensitivity of H. armigera to fenvalerate, suggesting that P450 enzymes were involved in the pyrethroid resistance in the field strains. The results of quantitative RT-PCR indicated that eight P450 genes (CYP332A1, CYP4L11, CYP4L5, CYP4M6, CYP4M7, CYP6B7, CYP9A12, CYP9A14) were all significantly overexpressed in Hejian1 and Xiajin1 strains of H. armigera collected in 2013, and CYP4L5 was significantly overexpressed in all the 6 field strains collected in 2014. CYP332A1, CYP6B7 and CYP9A12 had very high overexpression levels in all the field strains, indicating their important roles in fenvalerate resistance. The results suggested that multiple P450 genes were involved in the high-level fenvalerate-resistance in different field strains of H. armigera collected from north of China. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Pro-inflammatory State in Monoclonal Gammopathy of Undetermined Significance and in Multiple Myeloma Is Characterized by Low Sialylation of Pathogen-Specific and Other Monoclonal Immunoglobulins

    Directory of Open Access Journals (Sweden)

    Adrien Bosseboeuf

    2017-10-01

    Full Text Available Multiple myeloma (MM and its pre-cancerous stage monoclonal gammopathy of undetermined significance (MGUS allow to study immune responses and the chronology of inflammation in the context of blood malignancies. Both diseases are characterized by the production of a monoclonal immunoglobulin (mc Ig which for subsets of MGUS and MM patients targets pathogens known to cause latent infection, a major cause of inflammation. Inflammation may influence the structure of both polyclonal (pc Ig and mc Ig produced by malignant plasma cells via the sialylation of Ig Fc fragment. Here, we characterized the sialylation of purified mc and pc IgGs from 148 MGUS and MM patients, in comparison to pc IgGs from 46 healthy volunteers. The inflammatory state of patients was assessed by the quantification in serum of 40 inflammation-linked cytokines, using Luminex technology. While pc IgGs from MGUS and MM patients showed heterogeneity in sialylation level, mc IgGs from both MGUS and MM patients exhibited a very low level of sialylation. Furthermore, mc IgGs from MM patients were less sialylated than mc IgGs from MGUS patients (p < 0.01, and mc IgGs found to target an infectious pathogen showed a lower level of sialylation than mc IgGs of undetermined specificity (p = 0.048. Regarding inflammation, 14 cytokines were similarly elevated with a p value < 0.0001 in MGUS and in MM compared to healthy controls. MM differed from MGUS by higher levels of HGF, IL-11, RANTES and SDF-1-α (p < 0.05. MGUS and MM patients presenting with hyposialylated pc IgGs had significantly higher levels of HGF, IL-6, tumor necrosis factor-α, TGF-β1, IL-17, and IL-33 compared to patients with hyper-sialylated pc IgGs (p < 0.05. In MGUS and in MM, the degree of sialylation of mc and pc IgGs and the levels of four cytokines important for the anti-microbial response were correlated, either positively (IFN-α2, IL-13 or negatively (IL-17, IL-33. Thus in MGUS as in MM

  9. Isolation and characterization of large spectrum and multiple bacteriocin-producing Enterococcus faecium strain from raw bovine milk.

    Science.gov (United States)

    Gaaloul, N; ben Braiek, O; Hani, K; Volski, A; Chikindas, M L; Ghrairi, T

    2015-02-01

    To assess the antimicrobial properties of lactic acid bacteria from Tunisian raw bovine milk. A bacteriocin-producing Enterococcus faecium strain was isolated from raw cow milk with activity against Gram-positive and Gram-negative bacteria. Antimicrobial substances produced by this strain were sensitive to proteolytic enzymes and were thermostable and resistant to a broad range of pH (2-10). Mode of action of antimicrobial substances was determined as bactericidal. Maximum activity was reached at the end of the exponential growth phase when checked against Listeria ivanovii BUG 496 (2366.62 AU ml(-1)). However, maximum antimicrobial activity against Pseudomonas aeruginosa 28753 was recorded at the beginning of the exponential growth phase. Enterococcus faecium GGN7 was characterized as free from virulence factors and was susceptible to tested antibiotics. PCR analysis of the micro-organism's genome revealed the presence of genes coding for enterocins A and B. Mass spectrometry analysis of RP-HPLC active fractions showed molecular masses corresponding to enterocins A (4835.77 Da) and B (5471.56 Da), and a peptide with a molecular mass of 3215.5 Da active only against Gram-negative indicator strains. The latter was unique in the databases. Enterococcus faecium GGN7 produces three bacteriocins with different inhibitory spectra. Based on its antimicrobial properties and safety, Ent. faecium GGN7 is potentially useful for food biopreservation. The results suggest the bacteriocins from GGN7 strain could be useful for food biopreservation. © 2014 The Society for Applied Microbiology.

  10. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli.

    Science.gov (United States)

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili; Christensen, Jens P; Olsen, John E; Nolan, Lisa; Olsen, Rikke H

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy and welfare worldwide. An almost defining characteristic of avian pathogenic E. coli is the carriage of plasmids, which may encode virulence factors and antibiotic resistance determinates. For the same reason, plasmids of avian pathogenic E. coli have been intensively studied. However, genes encoded by the chromosome may also be important for disease manifestation and antimicrobial resistance. For the E. coli strain APEC_O2 the plasmids have been sequenced and analyzed in several studies, and E. coli APEC_O2 may therefore serve as a reference strain in future studies. Here we describe the chromosomal features of E. coli APEC_O2. E. coli APEC_O2 is a sequence type ST135, has a chromosome of 4,908,820 bp (plasmid removed), comprising 4672 protein-coding genes, 110 RNA genes, and 156 pseudogenes, with an average G + C content of 50.69%. We identified 82 insertion sequences as well as 4672 protein coding sequences, 12 predicated genomic islands, three prophage-related sequences, and two clustered regularly interspaced short palindromic repeats regions on the chromosome, suggesting the possible occurrence of horizontal gene transfer in this strain. The wildtype strain of E. coli APEC_O2 is resistant towards multiple antimicrobials, however, no (complete) antibiotic resistance genes were present on the chromosome, but a number of genes associated with extra-intestinal disease were identified. Together, the information provided here on E. coli APEC_O2 will assist in future studies of avian pathogenic E. coli strains, in particular regarding strain of E. coli APEC_O2, and aid in the general understanding of the pathogenesis of avian pathogenic E. coli .

  11. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    Science.gov (United States)

    Harris, Jordan Lee; Balci, Yilmaz

    2015-01-01

    Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.

  12. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    Directory of Open Access Journals (Sweden)

    Jordan Lee Harris

    Full Text Available Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.

  13. InAs0.45P0.55/InP strained multiple quantum wells intermixed by inductively coupled plasma etching

    International Nuclear Information System (INIS)

    Cao, Meng; Wu, Hui-Zhen; Lao, Yan-Feng; Cao, Chun-Fang; Liu, Cheng

    2009-01-01

    The intermixing effect on InAs 0.45 P 0.55 /InP strained multiple quantum wells (SMQWs) by inductively coupled plasma (ICP) etching and rapid thermal annealing (RTA) is investigated. Experiments show that the process of ICP etching followed RTA induces the blue shift of low temperature photoluminescence (PL) peaks of QWs. With increasing etching depth, the PL intensities are firstly enhanced and then diminished. This phenomenon is attributed to the variation of surface roughness and microstructure transformation inside the QW structure during ICP processing.

  14. Genetic evidence for a high diversity and wide distribution of endemic strains of the pathogenic chytrid fungus Batrachochytrium dendrobatidis in wild Asian amphibians.

    Science.gov (United States)

    Bataille, Arnaud; Fong, Jonathan J; Cha, Moonsuk; Wogan, Guinevere O U; Baek, Hae Jun; Lee, Hang; Min, Mi-Sook; Waldman, Bruce

    2013-08-01

    Population declines and extinctions of amphibians have been attributed to the chytrid fungus Batrachochytrium dendrobatidis (Bd), especially one globally emerging recombinant lineage ('Bd-GPL'). We used PCR assays that target the ribosomal internal transcribed spacer region (ITS) of Bd to determine the prevalence and genetic diversity of Bd in South Korea, where Bd is widely distributed but is not known to cause morbidity or mortality in wild populations. We isolated Korean Bd strains from native amphibians with low infection loads and compared them to known worldwide Bd strains using 19 polymorphic SNP and microsatellite loci. Bd prevalence ranged between 12.5 and 48.0%, in 11 of 17 native Korean species, and 24.7% in the introduced bullfrog Lithobates catesbeianus. Based on ITS sequence variation, 47 of the 50 identified Korean haplotypes formed a group closely associated with a native Brazilian Bd lineage, separated from the Bd-GPL lineage. However, multilocus genotyping of three Korean Bd isolates revealed strong divergence from both Bd-GPL and the native Brazilian Bd lineages. Thus, the ITS region resolves genotypes that diverge from Bd-GPL but otherwise generates ambiguous phylogenies. Our results point to the presence of highly diversified endemic strains of Bd across Asian amphibian species. The rarity of Bd-GPL-associated haplotypes suggests that either this lineage was introduced into Korea only recently or Bd-GPL has been outcompeted by native Bd strains. Our results highlight the need to consider possible complex interactions among native Bd lineages, Bd-GPL and their associated amphibian hosts when assessing the spread and impact of Bd-GPL on worldwide amphibian populations. © 2013 John Wiley & Sons Ltd.

  15. Antibiotic Resistance, RAPD- PCR Typing of Multiple Drug Resistant Strains of Escherichia Coli From Urinary Tract Infection (UTI).

    Science.gov (United States)

    Marialouis, Xavier Alexander; Santhanam, Amutha

    2016-03-01

    Global spreading of multidrug resistant strains of Escherichia coli is responsible for Urinary Tract Infection (UTI) which is a major health problem in of concern. Among the gram negative bacteria, the major contributors for UTI belongs to the family Enterobacteriaceae, which includes E. coli, Klebsiella, Citrobacter and Proteus. However, E. coli accounts for the major cause of Urinary tract infections (UTIs) and accounts for 75% to 90% of UTI isolates. The main aim of this study is to analyse the phylogenetic grouping of clinical isolates of UTI E. coli. In this study nearly 58 E. coli strains were isolated and confirmed through microbiological, biochemical characterization. The urine samples were collected from outpatients having symptoms of UTI, irrespective of age and sex in Tamil Nadu, India. The isolates were subjected to analyse for ESBL and AmpC β-lactamase production. To understand its genetic correlation, molecular typing was carried out using RAPD-PCR method. Here we noted phenotypically twenty seven isolates were positive for ESBL and seven for AmpC β-lactamase production. However, among the ESBL isolates higher sensitivity was noted for Nitrofurantoin and Cefoxitin. It is worth to note that the prevalence of UTIs was more common among female and elderly male. Phylogenetic grouping revealed the presence of 24 isolates belonged to B2 group followed by 19 isolates to group A, eight isolates to group B1 and Seven isolates to group D. Phenotypically most of the strains were positive for ESBL and showed high sensitivity for Nitrofurantoin and cefoxitin.

  16. Unusual Multiple Production of N-Acylhomoserine Lactones a by Burkholderia sp. Strain C10B Isolated from Dentine Caries

    Directory of Open Access Journals (Sweden)

    Share Yuan Goh

    2014-05-01

    Full Text Available Bacteria realize the ability to communicate by production of quorum sensing (QS molecules called autoinducers, which regulate the physiological activities in their ecological niches. The oral cavity could be a potential area for the presence of QS bacteria. In this study, we report the isolation of a QS bacterial isolate C10B from dentine caries. Preliminary screening using Chromobacterium violaceum CV026 biosensor showed that isolate C10B was able to produce N-acylhomoserine lactones (AHLs. This bacterium was further identified as a member of Burkholderia, an opportunistic pathogen. The isolated Burkholderia sp. was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL, N-octanoyl-L-homoserine lactone (C8-HSL, N-decanoyl-L-homoserine lactone (C10-HSL and N-dodecanoyl-L-homoserine lactone (C12-HSL.

  17. Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing

    OpenAIRE

    Maria López; Maria López; Lucia Blasco; Eva Gato; Eva Gato; Astrid Perez; Astrid Perez; Laura Fernández-Garcia; Laura Fernández-Garcia; Luis Martínez-Martinez; Luis Martínez-Martinez; Luis Martínez-Martinez; Felipe Fernández-Cuenca; Felipe Fernández-Cuenca; Felipe Fernández-Cuenca

    2017-01-01

    Introduction:Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A...

  18. Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing

    OpenAIRE

    L?pez, Maria; Blasco, Lucia; Gato, Eva; Perez, Astrid; Fern?ndez-Garcia, Laura; Mart?nez-Martinez, Luis; Fern?ndez-Cuenca, Felipe; Rodr?guez-Ba?o, Jes?s; Pascual, Alvaro; Bou, German; Tom?s, Maria

    2017-01-01

    Introduction: Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of ...

  19. The Phytophthora sojae avirulence locus Avr3c encodes a multi-copy RXLR effector with sequence polymorphisms among pathogen strains.

    Directory of Open Access Journals (Sweden)

    Suomeng Dong

    Full Text Available Root and stem rot disease of soybean is caused by the oomycete Phytophthora sojae. The avirulence (Avr genes of P. sojae control race-cultivar compatibility. In this study, we identify the P. sojae Avr3c gene and show that it encodes a predicted RXLR effector protein of 220 amino acids. Sequence and transcriptional data were compared for predicted RXLR effectors occurring in the vicinity of Avr4/6, as genetic linkage of Avr3c and Avr4/6 was previously suggested. Mapping of DNA markers in a F(2 population was performed to determine whether selected RXLR effector genes co-segregate with the Avr3c phenotype. The results pointed to one RXLR candidate gene as likely to encode Avr3c. This was verified by testing selected genes by a co-bombardment assay on soybean plants with Rps3c, thus demonstrating functionality and confirming the identity of Avr3c. The Avr3c gene together with eight other predicted genes are part of a repetitive segment of 33.7 kb. Three near-identical copies of this segment occur in a tandem array. In P. sojae strain P6497, two identical copies of Avr3c occur within the repeated segments whereas the third copy of this RXLR effector has diverged in sequence. The Avr3c gene is expressed during the early stages of infection in all P. sojae strains examined. Virulent alleles of Avr3c that differ in amino acid sequence were identified in other strains of P. sojae. Gain of virulence was acquired through mutation and subsequent sequence exchanges between the two copies of Avr3c. The results illustrate the importance of segmental duplications and RXLR effector evolution in the control of race-cultivar compatibility in the P. sojae and soybean interaction.

  20. Multiplication in egg yolk and survival in egg albumen of genetically and phenotypically characterized Salmonella Enteritidis strains

    Science.gov (United States)

    Prompt refrigeration of eggs to prevent the multiplication of Salmonella Enteritidis to high levels during storage is an important practice for reducing the risk of egg-transmitted human illness. The efficacy of egg refrigeration for achieving this goal depends on the location of contamination, the ...

  1. Draft Genome Sequence Analysis of a Pseudomonas putida W15Oct28 Strain with Antagonistic Activity to Gram-Positive and Pseudomonas sp. Pathogens

    Science.gov (United States)

    Ye, Lumeng; Hildebrand, Falk; Dingemans, Jozef; Ballet, Steven; Laus, George; Matthijs, Sandra; Berendsen, Roeland; Cornelis, Pierre

    2014-01-01

    Pseudomonas putida is a member of the fluorescent pseudomonads known to produce the yellow-green fluorescent pyoverdine siderophore. P. putida W15Oct28, isolated from a stream in Brussels, was found to produce compound(s) with antimicrobial activity against the opportunistic pathogens Staphylococcus aureus, Pseudomonas aeruginosa, and the plant pathogen Pseudomonas syringae, an unusual characteristic for P. putida. The active compound production only occurred in media with low iron content and without organic nitrogen sources. Transposon mutants which lost their antimicrobial activity had the majority of insertions in genes involved in the biosynthesis of pyoverdine, although purified pyoverdine was not responsible for the antagonism. Separation of compounds present in culture supernatants revealed the presence of two fractions containing highly hydrophobic molecules active against P. aeruginosa. Analysis of the draft genome confirmed the presence of putisolvin biosynthesis genes and the corresponding lipopeptides were found to contribute to the antimicrobial activity. One cluster of ten genes was detected, comprising a NAD-dependent epimerase, an acetylornithine aminotransferase, an acyl CoA dehydrogenase, a short chain dehydrogenase, a fatty acid desaturase and three genes for a RND efflux pump. P. putida W15Oct28 genome also contains 56 genes encoding TonB-dependent receptors, conferring a high capacity to utilize pyoverdines from other pseudomonads. One unique feature of W15Oct28 is also the presence of different secretion systems including a full set of genes for type IV secretion, and several genes for type VI secretion and their VgrG effectors. PMID:25369289

  2. Isolation, identification of antagonistic rhizobacterial strains obtained from chickpea (cicer arietinum l.) field and their in-vitro evaluation against fungal root pathogens

    International Nuclear Information System (INIS)

    Shahzaman, S.; Haq, I.U.; Mukhtar, T.; Naeem, M.

    2015-01-01

    Plant growth promoting rhizobacteria (PGPR), are associated with roots, found in the rhizosphere and can directly or indirectly enhance the plant growth. In this study soil was collected from rhizosphere of chickpea fields of different areas of Rawalpindi division of Pakistan. PGPR were isolated, screened and characterized. Eight isolates of rhizobacteria (RHA, RPG, RFJ, RC, RTR, RT and RK) were isolated from Rawalpindi division and were characterized. The antagonistic activity of these PGPR isolates against root infecting fungi (Fusarium oxysporum and Verticillium spp.,) was done and production of indole acetic acid (IAA), siderophore and P-solubilization was evaluated. The isolates RHA, RPG, RFJ, RC, RRD and RT were found to be positive in producing siderophore, IAA and P-solubilization. Furthermore, most of the isolates showed antifungal activity against Fusarium oxysporum, and Verticillium spp. The rhizobacterial isolates RHA, RPG, RFJ, RC, RRD, RTR, RT and RK were used as bio-inoculants that might be beneficial for chickpea cultivation as the rhizobacterial isolates possessed the plant growth promoting characters i.e. siderophore, IAA production, phosphate solubilization. In in vitro tests, Pseudomonas sp. and Bacillus spp. inhibited the mycelial growth of the fungal root pathogens. The isolates (RHA and RPG) also significantly increased (60-70%) seed germination, shoot length, root length of the chickpea. The incidence of fungi was reduced by the colonization of RHA and RPG which enhanced the seedling vigor index and seed germination. The observations revealed that isolates RHA and RPG is quite effective to reduce the fungal root infection in greenhouse, and also increases seed yields significantly. These rhizobacterial isolates appear to be efficient yield increasing as well as effective biocontrol agent against fungal root pathogen. (author)

  3. The hydrocarbon-degrading marine bacterium Cobetia sp. strain MM1IDA2H-1 produces a biosurfactant that interferes with quorum sensing of fish pathogens by signal hijacking

    Science.gov (United States)

    Ibacache-Quiroga, C; Ojeda, J; Espinoza-Vergara, G; Olivero, P; Cuellar, M; Dinamarca, M A

    2013-01-01

    Summary Biosurfactants are produced by hydrocarbon-degrading marine bacteria in response to the presence of water-insoluble hydrocarbons. This is believed to facilitate the uptake of hydrocarbons by bacteria. However, these diffusible amphiphilic surface-active molecules are involved in several other biological functions such as microbial competition and intra-or inter-species communication. We report the isolation and characterization of a marine bacterial strain identified as Cobetia sp. MM1IDA2H-1, which can grow using the sulfur-containing heterocyclic aromatic hydrocarbon dibenzothiophene (DBT). As with DBT, when the isolated strain is grown in the presence of a microbial competitor, it produces a biosurfactant. Because the obtained biosurfactant was formed by hydroxy fatty acids and extracellular lipidic structures were observed during bacterial growth, we investigated whether the biosurfactant at its critical micelle concentration can interfere with bacterial communication systems such as quorum sensing. We focused on Aeromonas salmonicida subsp. salmonicida, a fish pathogen whose virulence relies on quorum sensing signals. Using biosensors for quorum sensing based on Chromobacterium violaceum and Vibrio anguillarum, we showed that when the purified biosurfactant was mixed with N-acyl homoserine lactones produced by A. salmonicida, quorum sensing was inhibited, although bacterial growth was not affected. In addition, the transcriptional activities of A. salmonicida virulence genes that are controlled by quorum sensing were repressed by both the purified biosurfactant and the growth in the presence of Cobetia sp. MM1IDA2H-1. We propose that the biosurfactant, or the lipid structures interact with the N-acyl homoserine lactones, inhibiting their function. This could be used as a strategy to interfere with the quorum sensing systems of bacterial fish pathogens, which represents an attractive alternative to classical antimicrobial therapies in fish

  4. Anti-pathogenic and probiotic attributes of Lactobacillus salivarius and Lactobacillus plantarum strains isolated from feces of Algerian infants and adults.

    Science.gov (United States)

    Ait Seddik, Hamza; Bendali, Farida; Cudennec, Benoit; Drider, Djamel

    2017-04-01

    Sixty-seven (67) lactic acid bacteria (LAB) isolates belonging to Lactobacillus genus were isolated from human feces and tested for their auto-aggregation and cell surface hydrophobicity in order to establish their adhesion capabilities, a prerequisite for probiotic selection. Strains with the upmost auto-aggregation and cell surface hydrophobicity scores were identified by MALDI-TOF spectrometry and 16S rDNA sequencing as Lactobacillus plantarum (p25lb1 and p98lb1) and Lactobacillus salivarius (p85lb1 and p104lb1). These strains were also able to adhere to human epithelial colorectal adenocarcinoma Caco-2 cells, with percentages ranging from 4.68 to 9.59%. They displayed good survival under conditions mimicking the gastrointestinal environment and remarkably impeded adhesion and invasion of human Caco-2 by Listeria monocytogenes and Enteropathogenic Escherichia coli. It should also be noted that Lb. plantarum p98lb1 was able to reduce in vitro cholesterol concentration by about 32%, offering an additional health attribute. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  5. Emerging Chlamydia psittaci infections in the chicken industry and pathology of Chlamydia psittaci genotype B and D strains in specific pathogen free chickens.

    Science.gov (United States)

    Yin, Lizi; Kalmar, Isabelle D; Lagae, Stefanie; Vandendriessche, Stien; Vanderhaeghen, Wannes; Butaye, Patrick; Cox, Eric; Vanrompay, Daisy

    2013-03-23

    Sera of 30 Belgian and 10 Northern French chicken farms were tested by a Chlamydia (C.) psittaci major outer membrane protein (MOMP) based ELISA. Ninety-six percent, 93% and 90% of the Belgian broilers, broiler breeders and layers were seropositive. Ninety-one percent of the French broilers were seropositive. In addition, tissues of 5 Belgian and 5 French broiler farms were examined at slaughter. All French farms were culture positive while C. psittaci was cultured from the lungs of 80% of examined Belgian farms. C. psittaci infections are apparently emerging in chickens raised in Belgium and Northern France. We could proof Hill-Evans postulates for chicken-derived C. psittaci genotype B and D strains. Chicken-processing plant employees should be considered a risk group for human psittacosis. There is a need for higher awareness and for efficient risk assessment and management of C. psittaci infections in chickens as chlamydiosis in broilers seems to be underdiagnosed and infections with highly virulent strains do occur. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. A genomic library-based amplification approach (GL-PCR) for the mapping of multiple IS6110 insertion sites and strain differentiation of Mycobacterium tuberculosis.

    Science.gov (United States)

    Namouchi, Amine; Mardassi, Helmi

    2006-11-01

    Evidence suggests that insertion of the IS6110 element is not without consequence to the biology of Mycobacterium tuberculosis complex strains. Thus, mapping of multiple IS6110 insertion sites in the genome of biomedically relevant clinical isolates would result in a better understanding of the role of this mobile element, particularly with regard to transmission, adaptability and virulence. In the present paper, we describe a versatile strategy, referred to as GL-PCR, that amplifies IS6110-flanking sequences based on the construction of a genomic library. M. tuberculosis chromosomal DNA is fully digested with HincII and then ligated into a plasmid vector between T7 and T3 promoter sequences. The ligation reaction product is transformed into Escherichia coli and selective PCR amplification targeting both 5' and 3' IS6110-flanking sequences are performed on the plasmid library DNA. For this purpose, four separate PCR reactions are performed, each combining an outward primer specific for one IS6110 end with either T7 or T3 primer. Determination of the nucleotide sequence of the PCR products generated from a single ligation reaction allowed mapping of 21 out of the 24 IS6110 copies of two 12 banded M. tuberculosis strains, yielding an overall sensitivity of 87,5%. Furthermore, by simply comparing the migration pattern of GL-PCR-generated products, the strategy proved to be as valuable as IS6110 RFLP for molecular typing of M. tuberculosis complex strains. Importantly, GL-PCR was able to discriminate between strains differing by a single IS6110 band.

  7. Outbreak of Invasive Wound Mucormycosis in a Burn Unit Due to Multiple Strains of Mucor circinelloides f. circinelloides Resolved by Whole-Genome Sequencing

    Directory of Open Access Journals (Sweden)

    Dea Garcia-Hermoso

    2018-04-01

    Full Text Available Mucorales are ubiquitous environmental molds responsible for mucormycosis in diabetic, immunocompromised, and severely burned patients. Small outbreaks of invasive wound mucormycosis (IWM have already been reported in burn units without extensive microbiological investigations. We faced an outbreak of IWM in our center and investigated the clinical isolates with whole-genome sequencing (WGS analysis. We analyzed M. circinelloides isolates from patients in our burn unit (BU1, Héééôèéééûéôèôèôôèéôééôéôôèôpital Saint-Louis, Paris, France together with nonoutbreak isolates from Burn Unit 2 (BU2, Paris area and from France over a 2-year period (2013 to 2015. A total of 21 isolates, including 14 isolates from six BU1 patients, were analyzed by whole-genome sequencing (WGS. Phylogenetic classification based on de novo assembly and assembly free approaches showed that the clinical isolates clustered in four highly divergent clades. Clade 1 contained at least one of the strains from the six epidemiologically linked BU1 patients. The clinical isolates were specific to each patient. Two patients were infected with more than two strains from different clades, suggesting that an environmental reservoir of clonally unrelated isolates was the source of contamination. Only two patients from BU1 shared one strain, which could correspond to direct transmission or contamination with the same environmental source. In conclusion, WGS of several isolates per patients coupled with precise epidemiological data revealed a complex situation combining potential cross-transmission between patients and multiple contaminations with a heterogeneous pool of strains from a cryptic environmental reservoir.

  8. The isolation and characterization of new C. thermocellum strains and the evaluation of multiple anaerobic digestion systems

    Science.gov (United States)

    Lv, Wen

    The overall objective of my research was to improve the efficiencies of bioconversions that produce renewable energy from lignocellulosic biomass. To this end, my studies addressed issues important to two promising strategies: consolidated bioprocessing (CBP) and anaerobic digestion (AD). CBP achieves saccharolytic enzyme production, hydrolysis, and fermentation in a single step and is considered to be the most cost-effective model. Anaerobic bacteria that can be used in CBP are highly desirable. To that end, two thermophilic and cellulolytic bacterial strains were isolated and characterized (Chapter 3). Based on 16S rRNA gene sequence analysis, both strains CS7 and CS8 are closely related to Clostridium thermocellum ATCC 27405. However, they had significantly higher specific cellulase activities and ethanol/acetate ratios than C. thermocellum ATCC 27405. As a result, CS7 and CS8 are two new highly cellulolytic and ethanologenic C. thermocellum strains, with application potentials in research and development of CBP. As some of the most promising AD processes, two temperature-phased AD (TPAD) systems, in comparison with a thermophilic single-stage AD (TSAD) system and a mesophilic two-stage AD (MTAD) system, were studied in treating high-strength dairy cattle manure. The TPAD systems, with the thermophilic digesters acidified (AT-TPAD, Chapter 4) or operated at neutral pH (NT-TPAD, Chapter 5), were optimized at the thermophilic temperature of 50°C and a volume ratio between the thermophilic and the mesophilic digesters of 1:2. Despite similar methane productions, the NT-TPAD system achieved significantly higher volatile solid (VS) removal than the AT-TPAD system and needed no external pH adjustments (Chapter 6). At the same overall OLR, the TSAD system achieved the highest performance, followed by the NT-TPAD and the MTAD systems (Chapter 7). Each digester harbored distinct yet dynamic microbial populations, some of which were significantly correlated or associated

  9. Systemically administered DNA and fowlpox recombinants expressing four vaccinia virus genes although immunogenic do not protect mice against the highly pathogenic IHD-J vaccinia strain.

    Science.gov (United States)

    Bissa, Massimiliano; Pacchioni, Sole Maria; Zanotto, Carlo; De Giuli Morghen, Carlo; Illiano, Elena; Granucci, Francesca; Zanoni, Ivan; Broggi, Achille; Radaelli, Antonia

    2013-12-26

    The first-generation smallpox vaccine was based on live vaccinia virus (VV) and it successfully eradicated the disease worldwide. Therefore, it was not administered any more after 1980, as smallpox no longer existed as a natural infection. However, emerging threats by terrorist organisations has prompted new programmes for second-generation vaccine development based on attenuated VV strains, which have been shown to cause rare but serious adverse events in immunocompromised patients. Considering the closely related animal poxviruses that might also be used as bioweapons, and the increasing number of unvaccinated young people and AIDS-affected immunocompromised subjects, a safer and more effective smallpox vaccine is still required. New avipoxvirus-based vectors should improve the safety of conventional vaccines, and protect from newly emerging zoonotic orthopoxvirus diseases and from the threat of deliberate release of variola or monkeypox virus in a bioterrorist attack. In this study, DNA and fowlpox recombinants expressing the L1R, A27L, A33R and B5R genes were constructed and evaluated in a pre-clinical trial in mouse, following six prime/boost immunisation regimens, to compare their immunogenicity and protective efficacy against a challenge with the lethal VV IHD-J strain. Although higher numbers of VV-specific IFNγ-producing T lymphocytes were observed in the protected mice, the cytotoxic T-lymphocyte response and the presence of neutralising antibodies did not always correlate with protection. In spite of previous successful results in mice, rabbits and monkeys, where SIV/HIV transgenes were expressed by the fowlpox vector, the immune response elicited by these recombinants was low, and most of the mice were not protected. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. An intermediate level of CD161 expression defines a novel activated, inflammatory, and pathogenic subset of CD8+ T cells involved in multiple sclerosis.

    Science.gov (United States)

    Nicol, Bryan; Salou, Marion; Vogel, Isabel; Garcia, Alexandra; Dugast, Emilie; Morille, Jeremy; Kilens, Stéphanie; Charpentier, Eric; Donnart, Audrey; Nedellec, Steven; Jacq-Foucher, Marylène; Le Frère, Fabienne; Wiertlewski, Sandrine; Bourreille, Arnaud; Brouard, Sophie; Michel, Laure; David, Laurent; Gourraud, Pierre-Antoine; Degauque, Nicolas; Nicot, Arnaud B; Berthelot, Laureline; Laplaud, David-Axel

    2018-03-01

    Several lines of evidence support a key role for CD8 + T cells in central nervous system tissue damage of patients with multiple sclerosis. However, the precise phenotype of the circulating CD8 + T cells that may be recruited from the peripheral blood to invade the CNS remains largely undefined to date. It has been suggested that IL-17 secreting CD8 (Tc17) T cells may be involved, and in humans these cells are characterized by the expression of CD161. We focused our study on a unique and recently described subset of CD8 T cells characterized by an intermediate expression of CD161 as its role in neuroinflammation has not been investigated to date. The frequency, phenotype, and function of CD8 + T cells with an intermediate CD161 expression level were characterized ex-vivo, in vitro, and in situ using RNAseq, RT-PCR, flow cytometry, TCR sequencing, and immunohistofluorescence of cells derived from healthy volunteers (n = 61), MS subjects (n = 90), as well as inflammatory (n = 15) and non-inflammatory controls (n = 6). We report here that CD8 + CD161 int T cells present characteristics of effector cells, up-regulate cell-adhesion molecules and have an increased ability to cross the blood-brain barrier and to secrete IL-17, IFNγ, GM-CSF, and IL-22. We further demonstrate that these cells are recruited and enriched in the CNS of MS subjects where they produce IL-17. In the peripheral blood, RNAseq, RT-PCR, high-throughput TCR repertoire analyses, and flow cytometry confirmed an increased effector and transmigration pattern of these cells in MS patients, with the presence of supernumerary clones compared to healthy controls. Our data demonstrate that intermediate levels of CD161 expression identifies activated and effector CD8 + T cells with pathogenic properties that are recruited to MS lesions. This suggests that CD161 may represent a biomarker and a valid target for the treatment of neuroinflammation. Copyright © 2017 The Authors. Published by Elsevier Ltd

  11. Multiple hypersensitivity to mutagens in a cell strain (46BR) derived from a patient with immuno-deficiencies

    International Nuclear Information System (INIS)

    Teo, I.A.; Arlett, C.F.; Harcourt, S.A.; Priestley, A.; Broughton, B.C.

    1983-01-01

    46BR is a fibroblast cell strain established from an individual with hypogammaglobulinaemia. The cells are unique in showing hypersensitivity to the lethal effects of a wide range of DNA-damaging agents. Thus they are hypersensitive to #betta#- and 254-nm UV-irradiation and show a limited capacity to repair potentially lethal #betta#-irradiation damage when compared with fibroblasts from normal individuals. A slight hypersensitivity to mitomycin C was also revealed but we were not able to discriminate 46BR from normals with 4-nitroquinoline oxide. The cells were hypersensitive to the alkylating agents, dimethyl sulphate, methyl methanesulphonate, ethyl methanesulphonate, N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N-nitrosourea but not N-ethyl-N-nitrosourea. A consideration of the spectra of DNA lesions produced by these alkylating agents together with the sensitivity to ionising radiation and mitomycin C suggests that 46BR cells are defective in a repair step that is common to all agents. We suggest that the cells are defective in DNA polymerisation or ligation. Support for this suggestion comes from the absence of any hypersensitivity to N-ethyl-N-nitrosourea since its major reaction products are not removed by excision pathways that require polymerisation and ligation. (orig.)

  12. Studies on the O-specific polysaccharide of the lipopolysaccharide from the Pseudomonas mediterranea strain C5P1rad1, a bacterium pathogenic of tomato and chrysanthemum.

    Science.gov (United States)

    Zdorovenko, Evelina L; Cimmino, Alessio; Marchi, Guido; Shashkov, Alexander S; Fiori, Mario; Knirel, Yuriy A; Evidente, Antonio

    2017-08-07

    An O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Pseudomonas mediterranea strain C5P1rad1, the causal agents of tomato pith necrosis and Chrysanthemum stem rot, and studied by one- and two-dimensional 1 H and 13 C NMR spectroscopy. The following structure of the trisaccharide repeating unit of the OPS was established, which, to our knowledge, is unique among the known bacterial polysaccharide structures: →4)-β-d-ManpNAc3NAcA-(1 → 4)-β-d-ManpNAc3NAcA-(1 → 3)-α-d-QuipNAc4NAc-(1→ where QuiNAc4NAc and ManNAc3NAcA indicate 2,4-diacetamido-2,4,6-trideoxyglucose and 2,3-diacetamido-2,3-dideoxymannuronic acid, respectively. Pre-treatment of leaves with LPS or OPS preparations at 250 and 50 μg mL -1 did not inhibit development of a hypersensitivity reaction induced by P. mediterranea C5P1rad1 on tobacco, tomato and chrysanthemum plants. The same preparations at 250 μg mL -1 partially prevented elicitation of the hypersensitivity reaction by Pseudomonas syringae KVPT7RC on chrysanthemum but not tobacco and tomato. Copyright © 2017. Published by Elsevier Ltd.

  13. Challenge Pools of Hepatitis C Virus Genotypes 1–6 Prototype Strains: Replication Fitness and Pathogenicity in Chimpanzees and Human Liver–Chimeric Mouse Models

    Science.gov (United States)

    Bukh, Jens; Meuleman, Philip; Tellier, Raymond; Engle, Ronald E.; Feinstone, Stephen M.; Eder, Gerald; Satterfield, William C.; Govindarajan, Sugantha; Krawczynski, Krzysztof; Miller, Roger H.; Leroux-Roels, Geert; Purcell, Robert H.

    2010-01-01

    Chimpanzees represent the only animal model for studies of the natural history of hepatitis C virus (HCV). To generate virus stocks of important HCV variants, we infected chimpanzees with HCV strains of genotypes 1–6 and determined the infectivity titer of acute-phase plasma pools in additional animals. The courses of first- and second-passage infections were similar, with early appearance of viremia, HCV RNA titers of >104.7 IU/mL, and development of acute hepatitis; the chronicity rate was 56%. The challenge pools had titers of 103–105 chimpanzee infectious doses/mL. Human liver–chimeric mice developed high-titer infections after inoculation with the challenge viruses of genotypes 1–6. Inoculation studies with different doses of the genotype 1b pool suggested that a relatively high virus dose is required to consistently infect chimeric mice. The challenge pools represent a unique resource for studies of HCV molecular virology and for studies of pathogenesis, protective immunity, and vaccine efficacy in vivo. PMID:20353362

  14. Processes for managing pathogens.

    Science.gov (United States)

    Godfree, Alan; Farrell, Joseph

    2005-01-01

    Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles.

  15. Multiple antigens of Yersinia pestis delivered by live recombinant attenuated Salmonella vaccine strains elicit protective immunity against plague.

    Science.gov (United States)

    Sanapala, Shilpa; Rahav, Hannah; Patel, Hetal; Sun, Wei; Curtiss, Roy

    2016-05-05

    Based on our improved novel Salmonella vaccine delivery platform, we optimized the recombinant attenuated Salmonella typhimurium vaccine (RASV) χ12094 to deliver multiple Yersinia pestis antigens. These included LcrV196 (amino acids, 131-326), Psn encoded on pYA5383 and F1 encoded in the chromosome, their synthesis did not cause adverse effects on bacterial growth. Oral immunization with χ12094(pYA5383) simultaneously stimulated high antibody titers to LcrV, Psn and F1 in mice and presented complete protection against both subcutaneous (s.c.) and intranasal (i.n.) challenges with high lethal doses of Y. pestis CO92. Moreover, no deaths or other disease symptoms were observed in SCID mice orally immunized with χ12094(pYA5383) over a 60-day period. Therefore, the trivalent S. typhimurium-based live vaccine shows promise for a next-generation plague vaccine. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Strain-compensated (Ga,In)N/(Al,Ga)N/GaN multiple quantum wells for improved yellow/amber light emission

    Energy Technology Data Exchange (ETDEWEB)

    Lekhal, K.; Damilano, B., E-mail: bd@crhea.cnrs.fr; De Mierry, P.; Vennéguès, P. [CRHEA-CNRS, Centre de Recherche sur l' Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, Valbonne 06560 (France); Ngo, H. T.; Rosales, D.; Gil, B. [Laboratoire Charles Coulomb, CNRS-INP-UMR 5221, Université Montpellier 2, F-34095 Montpellier (France); Hussain, S. [CRHEA-CNRS, Centre de Recherche sur l' Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, Valbonne 06560 (France); Université de Nice Sophia Antipolis, Parc Valrose, 28 av. Valrose, 06108 Nice cedex 2 (France)

    2015-04-06

    Yellow/amber (570–600 nm) emitting In{sub x}Ga{sub 1−x}N/Al{sub y}Ga{sub 1−y}N/GaN multiple quantum wells (QWs) have been grown by metal organic chemical vapor deposition on GaN-on- sapphire templates. When the (Al,Ga)N thickness of the barrier increases, the room temperature photoluminescence is red-shifted while its yield increases. This is attributed to an increase of the QW internal electric field and an improvement of the material quality due to the compensation of the compressive strain of the In{sub x}Ga{sub 1−x}N QWs by the Al{sub y}Ga{sub 1−y}N layers, respectively.

  17. Effect of boron incorporation on the structural and photoluminescence properties of highly-strained InxGa1-xAs/GaAs multiple quantum wells

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2013-07-01

    Full Text Available In this research, 5-period highly-strained BInGaAs/GaAs multiple quantum wells (MQWs have been successfully grown at 480-510ºC by LP-MOCVD. Room-temperature photoluminescence (RT-PL measurements of BInGaAs/GaAs MQWs showed the peak wavelength as long as 1.17 μm with full-width at half maximum (FWHM of only 29.5 meV. In addition, a slight blue-shift (∼18 meV of PL peak energy of InxGa1-xAs/GaAs MQWs was observed after boron incorporation. It has been found boron incorporation ( 40%, the positive effect of boron incorporation prevailed, i.e., boron incorporation completely suppressed the thickness undulation and lead to the improvement of PL properties.

  18. Room Temperature Electroluminescence from Tensile-Strained Si0.13Ge0.87/Ge Multiple Quantum Wells on a Ge Virtual Substrate

    Directory of Open Access Journals (Sweden)

    Guangyang Lin

    2016-09-01

    Full Text Available Direct band electroluminescence (EL from tensile-strained Si0.13Ge0.87/Ge multiple quantum wells (MQWs on a Ge virtual substrate (VS at room temperature is reported herein. Due to the competitive result of quantum confinement Stark effect and bandgap narrowing induced by tensile strain in Ge wells, electroluminescence from Γ1-HH1 transition in 12-nm Ge wells was observed at around 1550 nm. As injection current density increases, additional emission shoulders from Γ2-HH2 transition in Ge wells and Ge VS appeared at around 1300–1400 nm and 1600–1700 nm, respectively. The peak energy of EL shifted to the lower energy side superquadratically with an increase of injection current density as a result of the Joule heating effect. During the elevation of environmental temperature, EL intensity increased due to a reduction of energy between L and Γ valleys of Ge. Empirical fitting of the relationship between the integrated intensity of EL (L and injection current density (J with L~Jm shows that the m factor increased with injection current density, suggesting higher light emitting efficiency of the diode at larger injection current densities, which can be attributed to larger carrier occupations in the Γ valley and the heavy hole (HH valance band at higher temperatures.

  19. Local strains, calorimetry, and magnetoresistance in adaptive martensite transition in multiple nanostrips of Ni39+x Mn50Sn11-x (x ⩽ 2) alloys.

    Science.gov (United States)

    Prasanna, A A; Ram, Shanker

    2013-02-01

    Ni 39+ x Mn 50 Sn 11- x ( x = 0.5, 1.0, 1.5 and 2) alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, ∼15 mm diameter and 8 mm width. A single martensite phase with a L 1 0 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% ( x = 2), whereas an austenite cubic L 2 1 phase turns up at smaller x ⩽ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips ( x ≽ 1.5) with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite-austenite (or reverse) phase transition. A net residual enthalpy change Δ H M↔A = -0.12 J g -1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (-)26% at 10 T is observed together with a large entropy change of 11.8 mJ g -1 K -1 , nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The Δ H M↔A irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features.

  20. Local strains, calorimetry, and magnetoresistance in adaptive martensite transition in multiple nanostrips of Ni39+xMn50Sn11−x(x ⩽ 2) alloys

    Science.gov (United States)

    Prasanna, A A; Ram, Shanker

    2013-01-01

    Ni39+xMn50Sn11−x (x = 0.5, 1.0, 1.5 and 2) alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, ∼15 mm diameter and 8 mm width. A single martensite phase with a L10 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% (x = 2), whereas an austenite cubic L21 phase turns up at smaller x ⩽ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips (x ≽ 1.5) with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite–austenite (or reverse) phase transition. A net residual enthalpy change ΔHM↔A = −0.12 J g−1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (–)26% at 10 T is observed together with a large entropy change of 11.8 mJ g−1 K−1, nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The ΔHM↔A irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features. PMID:27877562

  1. Local strains, calorimetry, and magnetoresistance in adaptive martensite transition in multiple nanostrips of Ni39+xMn50Sn11−x(x ≤ 2 alloys

    Directory of Open Access Journals (Sweden)

    A A Prasanna and Shanker Ram

    2013-01-01

    Full Text Available Ni39+xMn50Sn11−x (x = 0.5, 1.0, 1.5 and 2 alloys comprise multiple martensite nanostrips of nanocrystallites when cast in small discs, for example, ~15 mm diameter and 8 mm width. A single martensite phase with a L10 tetragonal crystal structure at room temperature can be formed at a critical Sn content of 9.0 at.% (x = 2, whereas an austenite cubic L21 phase turns up at smaller x ≤ 1.5. The decrease in the Sn content from x = 2 to 0.5 also results in a gradual increase in the crystallite size from 11 to 17 nm. Scanning electron microscopy images reveal arrays of regularly displaced multiple martensite strips (x ≥ 1.5 with an average thickness of 20 nm. As forced oscillators, these strips carry over the local strains, magnetic dipoles, and thermions simultaneously in a martensite–austenite (or reverse phase transition. A net residual enthalpy change ΔHM↔A = −0.12 J g−1 arises in the process that lacks reversibility between the cooling and heating cycles. A large magnetoresistance of (–26% at 10 T is observed together with a large entropy change of 11.8 mJ g−1 K−1, nearly twice the value ever reported in such alloys, in the isothermal magnetization at 311 K. The ΔHM↔A irreversibility accounts for a thermal hysteresis in the electrical resistivity. Strain induced in the martensite strips leads them to have a higher electrical resistivity than that of the higher-temperature austenite phase. A model considering time-dependent enthalpy relaxation explains the irreversibility features.

  2. Effects of Silver Nanoparticles on Multiple Drug-Resistant Strains of Staphylococcus aureus and Pseudomonas aeruginosa from Mastitis-Infected Goats: An Alternative Approach for Antimicrobial Therapy

    Directory of Open Access Journals (Sweden)

    Yu-Guo Yuan

    2017-03-01

    Full Text Available Recently, silver nanoparticles (AgNPs have been widely used in various applications as antimicrobial agents, anticancer, diagnostics, biomarkers, cell labels, and drug delivery systems for the treatment of various diseases. Microorganisms generally acquire resistance to antibiotics through the course of antibacterial therapy. Multi-drug resistance (MDR has become a growing problem in the treatment of infectious diseases, and the widespread use of broad-spectrum antibiotics has resulted in the development of antibiotic resistance by numerous human and animal bacterial pathogens. As a result, an increasing number of microorganisms are resistant to multiple antibiotics causing continuing economic losses in dairy farming. Therefore, there is an urgent need for the development of alternative, cost-effective, and efficient antimicrobial agents that overcome antimicrobial resistance. Here, AgNPs synthesized using the bio-molecule quercetin were characterized using various analytical techniques. The synthesized AgNPs were highly spherical in shape and had an average size of 11 nm. We evaluated the efficacy of synthesized AgNPs against two MDR pathogenic bacteria, namely, Pseudomonas aeruginosa and Staphylococcus aureus, which were isolated from milk samples produced by mastitis-infected goats. The minimum inhibitory concentrations (MICs of AgNPs against P. aeruginosa and S. aureus were found to be 1 and 2 μg/mL, respectively. Our findings suggest that AgNPs exert antibacterial effects in a dose- and time-dependent manner. Results from the present study demonstrate that the antibacterial activity of AgNPs is due to the generation of reactive oxygen species (ROS, malondialdehyde (MDA, and leakage of proteins and sugars in bacterial cells. Results of the present study showed that AgNP-treated bacteria had significantly lower lactate dehydrogenase activity (LDH and lower adenosine triphosphate (ATP levels compared to the control. Furthermore, Ag

  3. Multiple reassorted viruses as cause of highly pathogenic avian influenza A(H5N8) virus epidemic, the Netherlands, 2016

    NARCIS (Netherlands)

    Beerens, Nancy; Heutink, Rene; Bergervoet, Saskia A.; Harders, Frank; Bossers, Alex; Koch, Guus

    2017-01-01

    In 2016, an epidemic of highly pathogenic avian influenza A virus subtype H5N8 in the Netherlands caused mass deaths among wild birds, and several commercial poultry farms and captive bird holdings were affected. We performed complete genome sequencing to study the relationship between the wild bird

  4. Multiple dislocation pile-ups in small grains at small strains: implications for the Hall-Petch relationship and backstress screening

    International Nuclear Information System (INIS)

    Schouwenaars, R; Jacobo, V H; Ortiz, A

    2014-01-01

    A classic explanation for the Hall-Petch relationship is given by the stress field of a single dislocation pile-up perpendicular to the grain boundary. Similarly, the gradual compensation of the stress fields of pile-ups on both sides of the boundary has been invoked to explain the transitory effects observed in the stress- strain curves of ultrafine grained polycrystals. This paper studies the effects of introducing deviations of the highly simplified geometry mentioned above, using the proper mathematical approximations of linear elastic dislocation theory. Multiple pile-ups invalidate the conclusions drawn from the single pile-up model. Pile-ups in multiple grains are assessed by a highly idealised model of an infinite array of periodical pile-ups. In the latter case, screening is always perfect. By considering the Peach-Köhler force between dislocations mutually disoriented grains, the magnitude of the fluctuations around such ideal case can be estimated. However, using sound probabilistic arguments to calculate the free path for dislocation slip in fine-grained polycrystals, it is found that the amount of dislocations that can be stored in the pile- ups is generally too small to explain the strong grain size effects observed experimentally

  5. Antimicrobial activity of Lactobacillus and Bifidobacterium strains against pathogenic microorganisms “in vitro”Atividade antimicrobiana de Lactobacillus e Bifodobacterium frente a microrganismos patogênicos “in vitro”

    Directory of Open Access Journals (Sweden)

    Giselle Nobre Costa

    2012-10-01

    Full Text Available Lactobacilli and bifidobacteria have a long history of safe use in foods. These bacteria have biotechnological characteristics of interest such as the inhibition of pathogens. In this work, two lactobacilli strain and a bifidobacterium strain isolated from human gut were evaluated concerning to their ability to inhibit pathogenic microorganisms in foods by diffusion agar tests. Moreover, we assessed the metabolites produced in culture broth under static and shaking growth to simulate anaerobiosis and aerobiosis conditions, respectively. L. acidophilus LA5, L. plantarum DCTA 8420 and B. lactis DCTA 8724 showed ability to inhibit S. aureus FRI 196, strains producer toxins A and D, as well as B. cereus ATCC 25923, E. coli ATCC 25922 and S. Enteritidis, whose inhibition halos reached, on average, 24 mm in diameter. In the agar diffusion method with concentrated culture medium, it was possible to observe the effect of oxygen on the production of toxic substances. This result showed that cultivation of Lactobacillus under aerobic conditions seems to exert greater inhibitory effect, whereas for Bifidobacterium strain the effect was the opposite.Lactobacilos e bifidobactérias apresentam um longo histórico de uso seguro em alimentos, além de apresentarem características de interesse biotecnológico como a inibição de patógenos. Neste trabalho duas linhagens de lactobacilos e uma de bifidobactéria, isoladas do intestino humano, foram avaliadas em testes de difusão em ágar, quanto à capacidade de inibição de microrganismos patogênicos de ocorrência comuns em toxinfecções alimentares. Adicionalmente, foram avaliados os metabólitos produzidos em caldo de cultivo estático e em agitação para simular condições de anaerobiose a aerobiose, respectivamente. As três bactérias, L. acidophilus LA5, L. plantarum DCTA 8420 e B. lactis DCTA 8724 apresentaram capacidade de inibição para S. aureus FRI 196 linhagem produtora de toxinas A e D

  6. Survey of clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) systems in multiple sequenced strains of Klebsiella pneumoniae.

    Science.gov (United States)

    Ostria-Hernández, Martha Lorena; Sánchez-Vallejo, Carlos Javier; Ibarra, J Antonio; Castro-Escarpulli, Graciela

    2015-08-04

    In recent years the emergence of multidrug resistant Klebsiella pneumoniae strains has been an increasingly common event. This opportunistic species is one of the five main bacterial pathogens that cause hospital infections worldwide and multidrug resistance has been associated with the presence of high molecular weight plasmids. Plasmids are generally acquired through horizontal transfer and therefore is possible that systems that prevent the entry of foreign genetic material are inactive or absent. One of these systems is CRISPR/Cas. However, little is known regarding the clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) system in K. pneumoniae. The adaptive immune system CRISPR/Cas has been shown to limit the entry of foreign genetic elements into bacterial organisms and in some bacteria it has been shown to be involved in regulation of virulence genes. Thus in this work we used bioinformatics tools to determine the presence or absence of CRISPR/Cas systems in available K. pneumoniae genomes. The complete CRISPR/Cas system was identified in two out of the eight complete K. pneumoniae genomes sequences and in four out of the 44 available draft genomes sequences. The cas genes in these strains comprises eight cas genes similar to those found in Escherichia coli, suggesting they belong to the type I-E group, although their arrangement is slightly different. As for the CRISPR sequences, the average lengths of the direct repeats and spacers were 29 and 33 bp, respectively. BLAST searches demonstrated that 38 of the 116 spacer sequences (33%) are significantly similar to either plasmid, phage or genome sequences, while the remaining 78 sequences (67%) showed no significant similarity to other sequences. The region where the CRISPR/Cas systems were located is the same in all the Klebsiella genomes containing it, it has a syntenic architecture, and is located among genes encoding for proteins likely involved in

  7. Antibiotic Resistance in Foodborne Pathogens

    OpenAIRE

    Walsh, Ciara; Duffy, Geraldine

    2013-01-01

    Wide-spread antibiotic resistance among bacterial pathogens is now a serious public health issue and multi-antibiotic resistance has been reported in many foodborne pathogens including Salmonella and E. coli. A study to determine antibiotic resistance profiles of a range of Salmonella and Verocytotoxigenic E.coli (VTEC) isolated from Irish foods revealed significant levels of antibiotic resistance in the strains. S. typhimurium DT104 were multiantibiotic resistant with 97% resistant to 7 anti...

  8. Bacterial size matters: Multiple mechanisms controlling septum cleavage and diplococcus formation are critical for the virulence of the opportunistic pathogen Enterococcus faecalis

    Science.gov (United States)

    Salamaga, Bartłomiej; Prajsnar, Tomasz K.; Willemse, Joost; Bewley, Martin A.; Chau, Françoise

    2017-01-01

    Enterococcus faecalis is an opportunistic pathogen frequently isolated in clinical settings. This organism is intrinsically resistant to several clinically relevant antibiotics and can transfer resistance to other pathogens. Although E. faecalis has emerged as a major nosocomial pathogen, the mechanisms underlying the virulence of this organism remain elusive. We studied the regulation of daughter cell separation during growth and explored the impact of this process on pathogenesis. We demonstrate that the activity of the AtlA peptidoglycan hydrolase, an enzyme dedicated to septum cleavage, is controlled by several mechanisms, including glycosylation and recognition of the peptidoglycan substrate. We show that the long cell chains of E. faecalis mutants are more susceptible to phagocytosis and are no longer able to cause lethality in the zebrafish model of infection. Altogether, this work indicates that control of cell separation during division underpins the pathogenesis of E. faecalis infections and represents a novel enterococcal virulence factor. We propose that inhibition of septum cleavage during division represents an attractive therapeutic strategy to control infections. PMID:28742152

  9. Bacterial size matters: Multiple mechanisms controlling septum cleavage and diplococcus formation are critical for the virulence of the opportunistic pathogen Enterococcus faecalis.

    Directory of Open Access Journals (Sweden)

    Bartłomiej Salamaga

    2017-07-01

    Full Text Available Enterococcus faecalis is an opportunistic pathogen frequently isolated in clinical settings. This organism is intrinsically resistant to several clinically relevant antibiotics and can transfer resistance to other pathogens. Although E. faecalis has emerged as a major nosocomial pathogen, the mechanisms underlying the virulence of this organism remain elusive. We studied the regulation of daughter cell separation during growth and explored the impact of this process on pathogenesis. We demonstrate that the activity of the AtlA peptidoglycan hydrolase, an enzyme dedicated to septum cleavage, is controlled by several mechanisms, including glycosylation and recognition of the peptidoglycan substrate. We show that the long cell chains of E. faecalis mutants are more susceptible to phagocytosis and are no longer able to cause lethality in the zebrafish model of infection. Altogether, this work indicates that control of cell separation during division underpins the pathogenesis of E. faecalis infections and represents a novel enterococcal virulence factor. We propose that inhibition of septum cleavage during division represents an attractive therapeutic strategy to control infections.

  10. In vitro inhibition of pathogenic Verticillium dahliae, causal agent of ...

    African Journals Online (AJOL)

    SAM

    2014-08-13

    Aug 13, 2014 ... In addition, plant pathogens directly affected through antibiosis and ... Trichoderma strains for antagonistic activity on the fungal pathogen V. ... Five soil sub samples were taken from the area around the healthy potato roots ...

  11. Swiss Army Pathogen: The Salmonella Entry Toolkit

    Directory of Open Access Journals (Sweden)

    Peter J. Hume

    2017-08-01

    Full Text Available Salmonella causes disease in humans and animals ranging from mild self-limiting gastroenteritis to potentially life-threatening typhoid fever. Salmonellosis remains a considerable cause of morbidity and mortality globally, and hence imposes a huge socio-economic burden worldwide. A key property of all pathogenic Salmonella strains is the ability to invade non-phagocytic host cells. The major determinant of this invasiveness is a Type 3 Secretion System (T3SS, a molecular syringe that injects virulence effector proteins directly into target host cells. These effectors cooperatively manipulate multiple host cell signaling pathways to drive pathogen internalization. Salmonella does not only rely on these injected effectors, but also uses several other T3SS-independent mechanisms to gain entry into host cells. This review summarizes our current understanding of the methods used by Salmonella for cell invasion, with a focus on the host signaling networks that must be coordinately exploited for the pathogen to achieve its goal.

  12. Reduction of Polarization Field Strength in Fully Strained c-Plane InGaN/(In)GaN Multiple Quantum Wells Grown by MOCVD.

    Science.gov (United States)

    Zhang, Feng; Ikeda, Masao; Zhang, Shu-Ming; Liu, Jian-Ping; Tian, Ai-Qin; Wen, Peng-Yan; Cheng, Yang; Yang, Hui

    2016-12-01

    The polarization fields in c-plane InGaN/(In)GaN multiple quantum well (MQW) structures grown on sapphire substrate by metal-organic chemical vapor deposition are investigated in this paper. The indium composition in the quantum wells varies from 14.8 to 26.5% for different samples. The photoluminescence wavelengths are calculated theoretically by fully considering the related effects and compared with the measured wavelengths. It is found that when the indium content is lower than 17.3%, the measured wavelengths agree well with the theoretical values. However, when the indium content is higher than 17.3%, the measured ones are much shorter than the calculation results. This discrepancy is attributed to the reduced polarization field in the MQWs. For the MQWs with lower indium content, 100% theoretical polarization can be maintained, while, when the indium content is higher, the polarization field decreases significantly. The polarization field can be weakened down to 23% of the theoretical value when the indium content is 26.5%. Strain relaxation is excluded as the origin of the polarization reduction because there is no sign of lattice relaxation in the structures, judging by the X-ray diffraction reciprocal space mapping. The possible causes of the polarization reduction are discussed.

  13. Effect of multiple short highly energetic X-ray pulses on the synthesis of endoglucanase by a mutant strain of Trichoderma reesei-M7

    International Nuclear Information System (INIS)

    Gemishev, Orlin; Markova, Maya; Savov, Valentin; Zapryanov, Stanislav; Blagoev, Alexander

    2014-01-01

    Bioconversion of cellulose-containing substrate to glucose represents an important area of modern biotechnology. Enzymes for the degradation of the polysaccharide part of biomass have been produced, mostly by fungi belonging to genus Trichoderma. Studies were carried out with the mutant strain Trichoderma reesei-M7, a cellulase producer. Spores of the enzyme producer were irradiated with different doses of characteristic X-ray radiation from metallic tungsten (mainly the W Ka1 and Ka2 lines) with a high dose rate. The latter is a specific property of the dense plasma focus (DPF) device, which has pulsed operation and thus gives short and highly energetic pulses of multiple types of rays and particles. In this case, we focused our study on the influence of hard X-rays. The doses of X-rays absorbed by the spores varied in the range of approximately 5-11,000 mSv measured with thermoluminescent dosimeters (TLD). The influence of the applied doses in combination with exceptionally high dose rates (in the order of tens of millisieverts per microsecond) on the activity of the produced endoglucanase, amount of biomass and extra-cellular protein, was studied in batch cultivation conditions. In the dose range of 200-1200 mSv, some enhancement of endoglucanase activity was obtained: around 18%-32%, despite the drop of the biomass amount, compared with the untreated material. Keywords: endoglucanase; X-ray pulses; thermoluminescent dosimeters (TLD); dense plasma focus (DPF); Trichoderma reesei

  14. A cell clone strain from Mythimna separata (Lepidoptera: Noctuidae) highly susceptible to Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and M. separata NPV (MsNPV).

    Science.gov (United States)

    Meng, Xiang-Qian; Zheng, Gui-Ling; Zhao, Chuan-De; Wan, Fang-Hao; Li, Chang-You

    2017-08-01

    In this study, we describe a cell line, Ms-10C, cloned from the line QAU-Ms-E-10 (simplified Ms-10), an embryonic line from Mythimna separata. The cloned cell line was significantly more sensitive to nucleopolyhedrovirus (NPV). Ms-10C cells were mainly spherical with a diameter of 14.42 ± 2.23 μm. DNA amplification fingerprinting (DAF) confirmed the profile of PCR-amplified bands of the cloned cell line was consistent with those of the parental cell line, Ms-10. The sequencing result of the mitochondrial cytochrome c oxidase I (mtCO I) fragment confirmed that the amplified 636-bps mtCOI fragment was 100% identical to that of M. separata. Its chromosomes exhibited the typical characters of lepidopteran cell lines. Its population doubling time was 42.2 h at 27°C. Ms-10C was more sensitive than Ms-10 to both Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and M. separata nucleopolyhedrovirus (MsNPV). At 4 d post infection, the infection rates of two viruses reached 94.2 and 92.3%, respectively. The availability of this cell clone strain will provide a useful tool for the basic research on nucleopolyhedrovirus and for potential application in expression of recombinant proteins with baculovirus expression vector system.

  15. Genetic characteristics and pathogenic mechanisms of periodontal pathogens.

    Science.gov (United States)

    Amano, A; Chen, C; Honma, K; Li, C; Settem, R P; Sharma, A

    2014-05-01

    Periodontal disease is caused by a group of bacteria that utilize a variety of strategies and molecular mechanisms to evade or overcome host defenses. Recent research has uncovered new evidence illuminating interesting aspects of the virulence of these bacteria and their genomic variability. This paper summarizes some of the strategies utilized by the major species - Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, and Porphyromonas gingivalis - implicated in the pathogenesis of periodontal disease. Whole-genome sequencing of 14 diverse A. actinomycetemcomitans strains has revealed variations in their genetic content (ranging between 0.4% and 19.5%) and organization. Strikingly, isolates from human periodontal sites showed no genomic changes during persistent colonization. T. forsythia manipulates the cytokine responses of macrophages and monocytes through its surface glycosylation. Studies have revealed that bacterial surface-expressed O-linked glycans modulate T-cell responses during periodontal inflammation. Periodontal pathogens belonging to the "red complex" consortium express neuraminidases, which enables them to scavenge sialic acid from host glycoconjugates. Analysis of recent data has demonstrated that the cleaved sialic acid acts as an important nutrient for bacterial growth and a molecule for the decoration of bacteria surfaces to help evade the host immune attack. In addition, bacterial entry into host cells is also an important prerequisite for the lifestyle of periodontal pathogens such as P. gingivalis. Studies have shown that, after its entry into the cell, this bacterium uses multiple sorting pathways destined for autophagy, lysosomes, or recycling pathways. In addition, P. gingivalis releases outer membrane vesicles which enter cells via endocytosis and cause cellular functional impairment.

  16. Distribution of triclosan-resistant genes in major pathogenic microorganisms revealed by metagenome and genome-wide analysis

    Science.gov (United States)

    Khan, Raees; Roy, Nazish; Choi, Kihyuck

    2018-01-01

    The substantial use of triclosan (TCS) has been aimed to kill pathogenic bacteria, but TCS resistance seems to be prevalent in microbial species and limited knowledge exists about TCS resistance determinants in a majority of pathogenic bacteria. We aimed to evaluate the distribution of TCS resistance determinants in major pathogenic bacteria (N = 231) and to assess the enrichment of potentially pathogenic genera in TCS contaminated environments. A TCS-resistant gene (TRG) database was constructed and experimentally validated to predict TCS resistance in major pathogenic bacteria. Genome-wide in silico analysis was performed to define the distribution of TCS-resistant determinants in major pathogens. Microbiome analysis of TCS contaminated soil samples was also performed to investigate the abundance of TCS-resistant pathogens. We experimentally confirmed that TCS resistance could be accurately predicted using genome-wide in silico analysis against TRG database. Predicted TCS resistant phenotypes were observed in all of the tested bacterial strains (N = 17), and heterologous expression of selected TCS resistant genes from those strains conferred expected levels of TCS resistance in an alternative host Escherichia coli. Moreover, genome-wide analysis revealed that potential TCS resistance determinants were abundant among the majority of human-associated pathogens (79%) and soil-borne plant pathogenic bacteria (98%). These included a variety of enoyl-acyl carrier protein reductase (ENRs) homologues, AcrB efflux pumps, and ENR substitutions. FabI ENR, which is the only known effective target for TCS, was either co-localized with other TCS resistance determinants or had TCS resistance-associated substitutions. Furthermore, microbiome analysis revealed that pathogenic genera with intrinsic TCS-resistant determinants exist in TCS contaminated environments. We conclude that TCS may not be as effective against the majority of bacterial pathogens as previously presumed

  17. Distribution of triclosan-resistant genes in major pathogenic microorganisms revealed by metagenome and genome-wide analysis.

    Directory of Open Access Journals (Sweden)

    Raees Khan

    Full Text Available The substantial use of triclosan (TCS has been aimed to kill pathogenic bacteria, but TCS resistance seems to be prevalent in microbial species and limited knowledge exists about TCS resistance determinants in a majority of pathogenic bacteria. We aimed to evaluate the distribution of TCS resistance determinants in major pathogenic bacteria (N = 231 and to assess the enrichment of potentially pathogenic genera in TCS contaminated environments. A TCS-resistant gene (TRG database was constructed and experimentally validated to predict TCS resistance in major pathogenic bacteria. Genome-wide in silico analysis was performed to define the distribution of TCS-resistant determinants in major pathogens. Microbiome analysis of TCS contaminated soil samples was also performed to investigate the abundance of TCS-resistant pathogens. We experimentally confirmed that TCS resistance could be accurately predicted using genome-wide in silico analysis against TRG database. Predicted TCS resistant phenotypes were observed in all of the tested bacterial strains (N = 17, and heterologous expression of selected TCS resistant genes from those strains conferred expected levels of TCS resistance in an alternative host Escherichia coli. Moreover, genome-wide analysis revealed that potential TCS resistance determinants were abundant among the majority of human-associated pathogens (79% and soil-borne plant pathogenic bacteria (98%. These included a variety of enoyl-acyl carrier protein reductase (ENRs homologues, AcrB efflux pumps, and ENR substitutions. FabI ENR, which is the only known effective target for TCS, was either co-localized with other TCS resistance determinants or had TCS resistance-associated substitutions. Furthermore, microbiome analysis revealed that pathogenic genera with intrinsic TCS-resistant determinants exist in TCS contaminated environments. We conclude that TCS may not be as effective against the majority of bacterial pathogens as previously

  18. Highly pathogenic avian influenza.

    Science.gov (United States)

    Swayne, D E; Suarez, D L

    2000-08-01

    Highly pathogenic (HP) avian influenza (AI) (HPAI) is an extremely contagious, multi-organ systemic disease of poultry leading to high mortality, and caused by some H5 and H7 subtypes of type A influenza virus, family Orthomyxoviridae. However, most AI virus strains are mildly pathogenic (MP) and produce either subclinical infections or respiratory and/or reproductive diseases in a variety of domestic and wild bird species. Highly pathogenic avian influenza is a List A disease of the Office International des Epizooties, while MPAI is neither a List A nor List B disease. Eighteen outbreaks of HPAI have been documented since the identification of AI virus as the cause of fowl plague in 1955. Mildly pathogenic avian influenza viruses are maintained in wild aquatic bird reservoirs, occasionally crossing over to domestic poultry and causing outbreaks of mild disease. Highly pathogenic avian influenza viruses do not have a recognised wild bird reservoir, but can occasionally be isolated from wild birds during outbreaks in domestic poultry. Highly pathogenic avian influenza viruses have been documented to arise from MPAI viruses through mutations in the haemagglutinin surface protein. Prevention of exposure to the virus and eradication are the accepted methods for dealing with HPAI. Control programmes, which imply allowing a low incidence of infection, are not an acceptable method for managing HPAI, but have been used during some outbreaks of MPAI. The components of a strategy to deal with MPAI or HPAI include surveillance and diagnosis, biosecurity, education, quarantine and depopulation. Vaccination has been used in some control and eradication programmes for AI.

  19. A novel approach for differentiating pathogenic and non-pathogenic Leptospira based on molecular fingerprinting.

    Science.gov (United States)

    Xiao, Di; Zhang, Cuicai; Zhang, Huifang; Li, Xiuwen; Jiang, Xiugao; Zhang, Jianzhong

    2015-04-24

    Leptospirosis is a worldwide, deadly zoonotic disease. Pathogenic Leptospira causes leptospirosis. The rapid and accurate identification of pathogenic and non-pathogenic Leptospira strains is essential for appropriate therapeutic management and timely intervention for infection control. The molecular fingerprint is a simple and rapid alternative tool for microorganisms identification, which is based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In this study, molecular fingerprint was performed to identify pathogenic strains of Leptospira. Phylogenetic analysis based on 16S rRNA gene sequences was used as the reference method. In addition, a label-free technique was used to reveal the different proteins of pathogenic or non-pathogenic Leptospira. A reference database was constructed using 30 Leptospira strains, including 16 pathogenic strains and 14 non-pathogenic strains. Two super reference spectra that were associated with pathogenicity were established. Overall, 33 Leptospira strains were used for validation, and 32 of 33 Leptospira strains could be identified on the species level and all the 33 could be classified as pathogenic or non-pathogenic. The super reference spectra and the major spectra projection (MSP) dendrogram correctly categorized the Leptospira strains into pathogenic and non-pathogenic groups, which was consistent with the 16S rRNA reference methods. Between the pathogenic and non-pathogenic strains, 108 proteins were differentially expressed. molecular fingerprint is an alternative to conventional molecular identification and can rapidly distinguish between pathogenic and non-pathogenic Leptospira strains. Therefore, molecular fingerprint may play an important role in the clinical diagnosis, treatment, surveillance, and tracking of epidemic outbreaks of leptospirosis. Leptospirosis is a worldwide zoonosis that is caused by spirochetes of the genus Leptospira. Leptospirosis is a serious zoonotic

  20. Pathogen intelligence

    Directory of Open Access Journals (Sweden)

    Michael eSteinert

    2014-01-01

    Full Text Available Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behaviour, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behaviour, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies.

  1. Epigenetic control of effectors in plant pathogens

    Directory of Open Access Journals (Sweden)

    Mark eGijzen

    2014-11-01

    Full Text Available Plant pathogens display impressive versatility in adapting to host immune systems. Pathogen effector proteins facilitate disease but can become avirulence (Avr factors when the host acquires discrete recognition capabilities that trigger immunity. The mechanisms that lead to changes to pathogen Avr factors that enable escape from host immunity are diverse, and include epigenetic switches that allow for reuse or recycling of effectors. This perspective outlines possibilities of how epigenetic control of Avr effector gene expression may have arisen and persisted in plant pathogens, and how it presents special problems for diagnosis and detection of specific pathogen strains or pathotypes.

  2. Antibiotic resistance and pathogenicity factors in Staphylococcus ...

    Indian Academy of Sciences (India)

    know which endemic strains of S. aureus in dairy cattle ... Antibiotic resistance; cattle; mastitis; MRSA; pathogenic genes ... recommended by Clinical and Laboratory Standards Institute ...... fnbA, eno, hla and nuc, did not show any relation to.

  3. Essential Oil from Origanum vulgare Completely Inhibits the Growth of Multidrug-Resistant Cystic Fibrosis Pathogens.

    Science.gov (United States)

    Pesavento, Giovanna; Maggini, Valentina; Maida, Isabel; Lo Nostro, Antonella; Calonico, Carmela; Sassoli, Chiara; Perrin, Elena; Fondi, Marco; Mengoni, Alessio; Chiellini, Carolina; Vannacci, Alfredo; Gallo, Eugenia; Gori, Luigi; Bogani, Patrizia; Bilia, Anna Rita; Campana, Silvia; Ravenni, Novella; Dolce, Daniela; Firenzuoli, Fabio; Fani, Renato

    2016-06-01

    Essential oils (EOs) are known to inhibit the growth of a wide range of microorganisms. Particularly interesting is the possible use of EOs to treat multidrug-resistant cystic fibrosis (CF) pathogens. We tested the essential oil (EO) from Origanum vulgare for in vitro antimicrobial activity, against three of the major human opportunistic pathogens responsible for respiratory infections in CF patients; these are methicillin-resistant Staphylococcus aureus, Stenotrophomonas maltophilia and Achromobacter xylosoxidans. Antibiotic susceptibility of each strain was previously tested by the standard disk diffusion method. Most strains were resistant to multiple antibiotics and could be defined as multi-drug-resistant (MDR). The antibacterial activity of O. vulgare EO (OEO) against a panel of 59 bacterial strains was evaluated, with MIC and MBC determined at 24, 48 and 72 hours by a microdilution method. The OEO was effective against all tested strains, although to a different extent. The MBC and MIC of OEO for S. aureus strains were either lower or equal to 0.50%, v/v, for A. xylosoxidans strains were lower or equal to 1% and 0.50%, v/v, respectively; and for S. maltophilia strains were lower or equal to 0.25%, v/v. The results from this study suggest that OEO might exert a role as an antimicrobial in the treatment of CF infections.

  4. Comparative genomic analysis shows that avian pathogenic Escherichia coli isolate IMT5155 (O2:K1:H5; ST complex 95, ST140 shares close relationship with ST95 APEC O1:K1 and human ExPEC O18:K1 strains.

    Directory of Open Access Journals (Sweden)

    Xiangkai Zhu Ge

    Full Text Available Avian pathogenic E. coli and human extraintestinal pathogenic E. coli serotypes O1, O2 and O18 strains isolated from different hosts are generally located in phylogroup B2 and ST complex 95, and they share similar genetic characteristics and pathogenicity, with no or minimal host specificity. They are popular objects for the study of ExPEC genetic characteristics and pathogenesis in recent years. Here, we investigated the evolution and genetic blueprint of APEC pathotype by performing phylogenetic and comparative genome analysis of avian pathogenic E. coli strain IMT5155 (O2:K1:H5; ST complex 95, ST140 with other E. coli pathotypes. Phylogeny analyses indicated that IMT5155 has closest evolutionary relationship with APEC O1, IHE3034, and UTI89. Comparative genomic analysis showed that IMT5155 and APEC O1 shared significant genetic overlap/similarities with human ExPEC dominant O18:K1 strains (IHE3034 and UTI89. Furthermore, the unique PAI I5155 (GI-12 was identified and found to be conserved in APEC O2 serotype isolates. GI-7 and GI-16 encoding two typical T6SSs in IMT5155 might be useful markers for the identification of ExPEC dominant serotypes (O1, O2, and O18 strains. IMT5155 contained a ColV plasmid p1ColV5155, which defined the APEC pathotype. The distribution analysis of 10 sequenced ExPEC pan-genome virulence factors among 47 sequenced E. coli strains provided meaningful information for B2 APEC/ExPEC-specific virulence factors, including several adhesins, invasins, toxins, iron acquisition systems, and so on. The pathogenicity tests of IMT5155 and other APEC O1:K1 and O2:K1 serotypes strains (isolated in China through four animal models showed that they were highly virulent for avian colisepticemia and able to cause septicemia and meningitis in neonatal rats, suggesting zoonotic potential of these APEC O1:K1 and O2:K1 isolates.

  5. Organic metabolites produced by Vibrio parahaemolyticus strain ...

    African Journals Online (AJOL)

    Identification and action of several antibacterial metabolites produced by a fish pathogen Vibrio parahaemolyticus strain An3 from marine ecosystem of Goa has been demonstrated. Antibacterial activity of the crude cell extract of the test bacterium has been evaluated against indicator pathogenic bacterial strains such as ...

  6. Strains of bacterial species induce a greatly varied acute adaptive immune response: The contribution of the accessory genome.

    Directory of Open Access Journals (Sweden)

    Uri Sela

    2018-01-01

    Full Text Available A fundamental question in human susceptibility to bacterial infections is to what extent variability is a function of differences in the pathogen species or in individual humans. To focus on the pathogen species, we compared in the same individual the human adaptive T and B cell immune response to multiple strains of two major human pathogens, Staphylococcus aureus and Streptococcus pyogenes. We found wide variability in the acute adaptive immune response induced by various strains of a species, with a unique combination of activation within the two arms of the adaptive response. Further, this was also accompanied by a dramatic difference in the intensity of the specific protective T helper (Th response. Importantly, the same immune response differences induced by the individual strains were maintained across multiple healthy human donors. A comparison of isogenic phage KO strains, demonstrated that of the pangenome, prophages were the major contributor to inter-strain immune heterogeneity, as the T cell response to the remaining "core genome" was noticeably blunted. Therefore, these findings extend and modify the notion of an adaptive response to a pathogenic bacterium, by implying that the adaptive immune response signature of a bacterial species should be defined either per strain or alternatively to the species' 'core genome', common to all of its strains. Further, our results demonstrate that the acquired immune response variation is as wide among different strains within a single pathogenic species as it is among different humans, and therefore may explain in part the clinical heterogeneity observed in patients infected with the same species.

  7. A new oligonucleotide microarray for detection of pathogenic and non-pathogenic Legionella spp.

    Directory of Open Access Journals (Sweden)

    Boyang Cao

    Full Text Available Legionella pneumophila has been recognized as the major cause of legionellosis since the discovery of the deadly disease. Legionella spp. other than L. pneumophila were later found to be responsible to many non-pneumophila infections. The non-L. pneumophila infections are likely under-detected because of a lack of effective diagnosis. In this report, we have sequenced the 16S-23S rRNA gene internal transcribed spacer (ITS of 10 Legionella species and subspecies, including L. anisa, L. bozemanii, L. dumoffii, L. fairfieldensis, L. gormanii, L. jordanis, L. maceachernii, L. micdadei, L. pneumophila subspp. fraseri and L. pneumophila subspp. pasculleii, and developed a rapid oligonucleotide microarray detection technique accordingly to identify 12 most common Legionella spp., which consist of 11 pathogenic species of L. anisa, L. bozemanii, L. dumoffii, L. gormanii, L. jordanis, L. longbeachae, L. maceachernii, L. micdadei, and L. pneumophila (including subspp. pneumophila, subspp. fraseri, and subspp. pasculleii and one non-pathogenic species, L. fairfieldensis. Twenty-nine probes that reproducibly detected multiple Legionella species with high specificity were included in the array. A total of 52 strains, including 30 target pathogens and 22 non-target bacteria, were used to verify the oligonucleotide microarray assay. The sensitivity of the detection was at 1.0 ng with genomic DNA or 13 CFU/100 mL with Legionella cultures. The microarray detected seven samples of air conditioner-condensed water with 100% accuracy, validating the technique as a promising method for applications in basic microbiology, clinical diagnosis, food safety, and epidemiological surveillance. The phylogenetic study based on the ITS has also revealed that the non-pathogenic L. fairfieldensis is the closest to L. pneumophila than the nine other pathogenic Legionella spp.

  8. A New Oligonucleotide Microarray for Detection of Pathogenic and Non-Pathogenic Legionella spp.

    Science.gov (United States)

    Cao, Boyang; Liu, Xiangqian; Yu, Xiang; Chen, Min; Feng, Lu; Wang, Lei

    2014-01-01

    Legionella pneumophila has been recognized as the major cause of legionellosis since the discovery of the deadly disease. Legionella spp. other than L. pneumophila were later found to be responsible to many non-pneumophila infections. The non-L. pneumophila infections are likely under-detected because of a lack of effective diagnosis. In this report, we have sequenced the 16S-23S rRNA gene internal transcribed spacer (ITS) of 10 Legionella species and subspecies, including L. anisa, L. bozemanii, L. dumoffii, L. fairfieldensis, L. gormanii, L. jordanis, L. maceachernii, L. micdadei, L. pneumophila subspp. fraseri and L. pneumophila subspp. pasculleii, and developed a rapid oligonucleotide microarray detection technique accordingly to identify 12 most common Legionella spp., which consist of 11 pathogenic species of L. anisa, L. bozemanii, L. dumoffii, L. gormanii, L. jordanis, L. longbeachae, L. maceachernii, L. micdadei, and L. pneumophila (including subspp. pneumophila, subspp. fraseri, and subspp. pasculleii) and one non-pathogenic species, L. fairfieldensis. Twenty-nine probes that reproducibly detected multiple Legionella species with high specificity were included in the array. A total of 52 strains, including 30 target pathogens and 22 non-target bacteria, were used to verify the oligonucleotide microarray assay. The sensitivity of the detection was at 1.0 ng with genomic DNA or 13 CFU/100 mL with Legionella cultures. The microarray detected seven samples of air conditioner-condensed water with 100% accuracy, validating the technique as a promising method for applications in basic microbiology, clinical diagnosis, food safety, and epidemiological surveillance. The phylogenetic study based on the ITS has also revealed that the non-pathogenic L. fairfieldensis is the closest to L. pneumophila than the nine other pathogenic Legionella spp. PMID:25469776

  9. Safety characterisation and inhibition of fungi and bacteria by a novel multiple enterocin-producing Enterococcus lactis 4CP3 strain.

    Science.gov (United States)

    Ben Braïek, Olfa; Cremonesi, Paola; Morandi, Stefano; Smaoui, Slim; Hani, Khaled; Ghrairi, Taoufik

    2018-03-07

    This study aims to characterise a potential bacteriocinogenic lactic acid bacterial strain isolated from a raw pink shrimp (Palaemon serratus) and evaluate its safety aspect. The strain designated as 4CP3 was noted to display antibacterial activities (P enterocins A, B and P. To our knowledge, this feature is newly described for E. lactis strain isolated from raw shrimps. Regarding safety aspect of E. lactis 4CP3, it has been demonstrated that this strain was not haemolytic, gelatinase negative, sensitive to vancomycin, and free of common antibiotic resistance genes and virulence factors. Therefore, it may be useful as a safe natural agent in preservation of foods or as a new probiotic strain in food and feed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Analysis of the diversity of murine antibodies to dextran B1355. II. Demonstration of multiple idiotypes with variable expression in several strains

    International Nuclear Information System (INIS)

    Hansburg, D.; Briles, D.E.; Davie, J.M.

    1977-01-01

    We have developed radioimmunoassays that detect idiotypic (variable region) differences among the α(1 → 3) dextran-binding myeloma proteins U102, J558, and M104 as well as an assay that detects variable region determinants common to all three proteins. Using these assays, we have examined 7S and 19S anti-α(1 → 3) dextran antibodies induced in five murine strains of the a 1 I/sub g/C/sub H/ linkage group and the recombinant strain BAB/14. All idiotypes were expressed in both 19S and 7S antibodies from all strains, but with considerable strain-specific variability in penetrance. In two strains, one additional type of antibody, which lacked all four idiotypic determinants, generally constituted the bulk of total anti-α(1 → 3) dextran antibodies

  11. CCR6+ Th cells in the cerebrospinal fluid of persons with multiple sclerosis are dominated by pathogenic non-classic Th1 cells and GM-CSF-only-secreting Th cells.

    Science.gov (United States)

    Restorick, S M; Durant, L; Kalra, S; Hassan-Smith, G; Rathbone, E; Douglas, M R; Curnow, S J

    2017-08-01

    Considerable attention has been given to CCR6 + IL-17-secreting CD4 + T cells (Th17) in the pathology of a number of autoimmune diseases including multiple sclerosis (MS). However, other Th subsets also play important pathogenic roles, including those that secrete IFNγ and GM-CSF. CCR6 expression by Th17 cells allows their migration across the choroid plexus into the cerebrospinal fluid (CSF), where they are involved in the early phase of experimental autoimmune encephalomyelitis (EAE), and in MS these cells are elevated in the CSF during relapses and contain high frequencies of autoreactive cells. However, the relatively low frequency of Th17 cells suggests they cannot by themselves account for the high percentage of CCR6 + cells in MS CSF. Here we identify the dominant CCR6 + T cell subsets in both the blood and CSF as non-classic Th1 cells, including many that secrete GM-CSF, a key encephalitogenic cytokine. In addition, we show that Th cells secreting GM-CSF but not IFNγ or IL-17, a subset termed GM-CSF-only-secreting Th cells, also accumulate in the CSF. Importantly, in MS the proportion of IFNγ- and GM-CSF-secreting T cells expressing CCR6 was significantly enriched in the CSF, and was elevated in MS, suggesting these cells play a pathogenic role in this disease. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Contamination of water resources by pathogenic bacteria

    Science.gov (United States)

    2014-01-01

    Water-borne pathogen contamination in water resources and related diseases are a major water quality concern throughout the world. Increasing interest in controlling water-borne pathogens in water resources evidenced by a large number of recent publications clearly attests to the need for studies that synthesize knowledge from multiple fields covering comparative aspects of pathogen contamination, and unify them in a single place in order to present and address the problem as a whole. Providing a broader perceptive of pathogen contamination in freshwater (rivers, lakes, reservoirs, groundwater) and saline water (estuaries and coastal waters) resources, this review paper attempts to develop the first comprehensive single source of existing information on pathogen contamination in multiple types of water resources. In addition, a comprehensive discussion describes the challenges associated with using indicator organisms. Potential impacts of water resources development on pathogen contamination as well as challenges that lie ahead for addressing pathogen contamination are also discussed. PMID:25006540

  13. Characterization and probiotic potential of Lactobacillus plantarum strains isolated from cheeses.

    Science.gov (United States)

    Zago, Miriam; Fornasari, Maria Emanuela; Carminati, Domenico; Burns, Patricia; Suàrez, Viviana; Vinderola, Gabriel; Reinheimer, Jorge; Giraffa, Giorgio

    2011-08-01

    Ninety-eight Lactobacillus plantarum strains isolated from Italian and Argentinean cheeses were evaluated for probiotic potential. After a preliminary subtractive screening based on the presence of msa and bsh genes, 27 strains were characterized. In general, the selected strains showed high resistance to lysozyme, good adaptation to simulated gastric juice, and a moderate to low bile tolerance. The capacity to agglutinate yeast cells in a mannose-specific manner, as well as the cell surface hydrophobicity was found to be variable among strains. Very high β-galactosidase activity was shown by a considerable number of the tested strains, whereas variable prebiotic utilization ability was observed. Only tetracycline resistance was observed in two highly resistant strains which harbored the tetM gene, whereas none of the strains showed β-glucuronidase activity or was capable of inhibiting pathogens. Three strains (Lp790, Lp813, and Lp998) were tested by in vivo trials. A considerable heterogeneity was found among a number of L. plantarum strains screened in this study, leading to the design of multiple cultures to cooperatively link strains showing the widest range of useful traits. Among the selected strains, Lp790, Lp813, and Lp998 showed the best probiotic potential and would be promising candidates for inclusion as starter cultures for the manufacture of probiotic fermented foods. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Pathogenic Acinetobacter: from the Cell Surface to Infinity and Beyond

    Science.gov (United States)

    Weber, Brent S.; Harding, Christian M.

    2015-01-01

    The genus Acinetobacter encompasses multiple nosocomial opportunistic pathogens that are of increasing worldwide relevance because of their ability to survive exposure to various antimicrobial and sterilization agents. Among these, Acinetobacter baumannii, Acinetobacter nosocomialis, and Acinetobacter pittii are the most frequently isolated in hospitals around the world. Despite the growing incidence of multidrug-resistant Acinetobacter spp., little is known about the factors that contribute to pathogenesis. New strategies for treating and managing infections caused by multidrug-resistant Acinetobacter strains are urgently needed, and this requires a detailed understanding of the pathobiology of these organisms. In recent years, some virulence factors important for Acinetobacter colonization have started to emerge. In this review, we focus on several recently described virulence factors that act at the bacterial surface level, such as the capsule, O-linked protein glycosylation, and adhesins. Furthermore, we describe the current knowledge regarding the type II and type VI secretion systems present in these strains. PMID:26712938

  15. Multiple-source tracking: Investigating sources of pathogens, nutrients, and sediment in the Upper Little River Basin, Kentucky, water years 2013–14

    Science.gov (United States)

    Crain, Angela S.; Cherry, Mac A.; Williamson, Tanja N.; Bunch, Aubrey R.

    2017-09-20

    The South Fork Little River (SFLR) and the North Fork Little River (NFLR) are two major headwater tributaries that flow into the Little River just south of Hopkinsville, Kentucky. Both tributaries are included in those water bodies in Kentucky and across the Nation that have been reported with declining water quality. Each tributary has been listed by the Kentucky Energy and Environment Cabinet—Kentucky Division of Water in the 303(d) List of Waters for Kentucky Report to Congress as impaired by nutrients, pathogens, and sediment for contact recreation from point and nonpoint sources since 2002. In 2009, the Kentucky Energy and Environment Cabinet—Kentucky Division of Water developed a pathogen total maximum daily load (TMDL) for the Little River Basin including the SFLR and NFLR Basins. Future nutrient and suspended-sediment TMDLs are planned once nutrient criteria and suspended-sediment protocols have been developed for Kentucky. In this study, different approaches were used to identify potential sources of fecal-indicator bacteria (FIB), nitrate, and suspended sediment; to inform the TMDL process; and to aid in the implementation of effective watershed-management activities. The main focus of source identification was in the SFLR Basin.To begin understanding the potential sources of fecal contamination, samples were collected at 19 sites for densities of FIB (E. coli) in water and fluvial sediment and at 11 sites for Bacteroidales genetic markers (General AllBac, human HF183, ruminant BoBac, canid BacCan, and waterfowl GFD) during the recreational season (May through October) in 2013 and 2014. Results indicated 34 percent of all E. coli water samples (n=227 samples) did not meet the U.S. Environmental Protection Agency 2012 recommended national criteria for primary recreational waters. No criterion currently exists for E. coli in fluvial sediment. By use of the Spearman’s rank correlation test, densities of FIB in fluvial sediments were observed to have a

  16. Foodborne pathogens

    Directory of Open Access Journals (Sweden)

    Thomas Bintsis

    2017-06-01

    Full Text Available Foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. The characteristics of the most common pathogenic bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cronobacter sakazakii, Esherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococccus aureus, Vibrio spp. and Yersinia enterocolitica, viruses (Hepatitis A and Noroviruses and parasites (Cyclospora cayetanensis, Toxoplasma gondii and Trichinella spiralis, together with some important outbreaks, are reviewed. Food safety management systems based on to classical hazard-based approach has been proved to be inefficient, and risk-based food safety approach is now suggested from leading researchers and organizations. In this context, a food safety management system should be designed in a way to estimate the risks to human health from food consumption and to identify, select and implement mitigation strategies in order to control and reduce these risks. In addition, the application of suitable food safety education programs for all involved people in the production and consumption of foods is suggested.

  17. Co-feeding transmission facilitates strain coexistence in Borrelia burgdorferi, the Lyme disease agent

    Directory of Open Access Journals (Sweden)

    S.L. States

    2017-06-01

    Full Text Available Coexistence of multiple tick-borne pathogens or strains is common in natural hosts and can be facilitated by resource partitioning of the host species, within-host localization, or by different transmission pathways. Most vector-borne pathogens are transmitted horizontally via systemic host infection, but transmission may occur in the absence of systemic infection between two vectors feeding in close proximity, enabling pathogens to minimize competition and escape the host immune response. In a laboratory study, we demonstrated that co-feeding transmission can occur for a rapidly-cleared strain of Borrelia burgdorferi, the Lyme disease agent, between two stages of the tick vector Ixodes scapularis while feeding on their dominant host, Peromyscus leucopus. In contrast, infections rapidly became systemic for the persistently infecting strain. In a field study, we assessed opportunities for co-feeding transmission by measuring co-occurrence of two tick stages on ears of small mammals over two years at multiple sites. Finally, in a modeling study, we assessed the importance of co-feeding on R0, the basic reproductive number. The model indicated that co-feeding increases the fitness of rapidly-cleared strains in regions with synchronous immature tick feeding. Our results are consistent with increased diversity of B. burgdorferi in areas of higher synchrony in immature feeding – such as the midwestern United States. A higher relative proportion of rapidly-cleared strains, which are less human pathogenic, would also explain lower Lyme disease incidence in this region. Finally, if co-feeding transmission also occurs on refractory hosts, it may facilitate the emergence and persistence of new pathogens with a more limited host range.

  18. Draft genome sequences of three Escherichia coli strains with different In Vivo pathogenicities in an avian (Ascending) infection model of the oviduct

    DEFF Research Database (Denmark)

    Olsen, Rikke Heidemann; Thøfner, Ida; Pors, Susanne Elisabeth

    2015-01-01

    Here, we present three draft genome sequences of Escherichia coli strains that experimentally were proven to possess low (strain D2-2), intermediate (Chronic_salp), or high virulence (Cp6salp3) in an avian (ascending) infection model of the oviduct.......Here, we present three draft genome sequences of Escherichia coli strains that experimentally were proven to possess low (strain D2-2), intermediate (Chronic_salp), or high virulence (Cp6salp3) in an avian (ascending) infection model of the oviduct....

  19. Multiple-locus variant-repeat assay (MLVA) is a useful tool for molecular epidemiologic analysis of Streptococcus agalactiae strains causing bovine mastitis.

    Science.gov (United States)

    Radtke, Andreas; Bruheim, Torkjel; Afset, Jan Egil; Bergh, Kåre

    2012-06-15

    Group B streptococci (GBS) were considered a major cause of mastitis in cattle until preventive measures succeeded in controlling the disease in the 1970s and 1980s. During the last 5-6 years an increasing number of cases have been observed in some Scandinavian countries. A total of 187 GBS isolates from mastitis cases were collected from 119 animals in 34 Norwegian farms in the period from April 2007 to November 2010. 133 (71%) of the isolates were from farms with automated milking systems. The strains underwent typing of capsular polysaccharides (CPS) and surface proteins, and were analyzed by multi-locus variable repeat assay (MLVA) to investigate the epidemiological relationship of strains within and between farms. The GBS strains were differentiated into 12 types by CPS and surface protein analysis, with CPS types V (54%) and IV (34%) predominating. MLVA was superior to CPS and protein typing for strain differentiation, resolving the 187 strains into 37 types. In 29 of 34 farms all GBS strains had identical MLVA profiles specific for each farm. However, in one farm represented with 48 isolates, four MLVA variants with differences in one repeat locus were observed during the almost 3-year long collection period. Similar variations were observed at four other farms. This might reflect the stability of repeat loci under in vivo conditions. Farms with automated milking systems were overrepresented in this material. In conclusion, the five-loci MLVA allowed rapid high-resolution genotyping of the bovine GBS strains within and between farms. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Pathogenicity and Host Range of Pathogen Causing Black Raspberry (Rubus coreanus) Anthracnose in Korea

    OpenAIRE

    Uh Seong Jeong; Ju Hee Kim; Ki Kwon Lee; Seong Soo Cheong; Wang Hyu Lee

    2013-01-01

    The strains of Colletotrichum gloeosporioides, C. coccodes, C. acutatum isolated from black raspberry werepathogenic to apple and strawberry after dropping inoculation, but showed weak pathogenicity in hot-pepperand tomato. The anthracnose pathogens of C. gloeosporioides, C. orbiculare, C. acutatum isolated from apple,hot-pepper and pumpkin showed pathogenicity in black raspberry. Moreover, the anthracnose pathogensisolated from apple caused disease symptoms in non-wounded inoculation.

  1. Effect of Bacteriophages on the Growth of Flavobacterium psychrophilum and Development of Phage-Resistant Strains

    DEFF Research Database (Denmark)

    Christiansen, Rói Hammershaimb; Madsen, Lone; Dalsgaard, Inger

    2016-01-01

    The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage concentr......The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage...... concentration (MOI = 0.3–4) was crucial for efficient viral lysis, resulting in a 104–105-fold reduction of phage-sensitive cells (both single phages and phage cocktails), which was maintained throughout the incubation (>10 days). Following cell lysis, regrowth of phage-resistant strains was examined...... and resistant strains were isolated for further characterization. The application of a mathematical model allowed simulation of phage-host interactions and resistance development, confirming indications from strain isolations that phage-sensitive strains dominated the regrowing population (>99.8 %) at low MOI...

  2. Pathogenicity of porcine intestinal spirochetes in gnotobiotic pigs.

    OpenAIRE

    Neef, N A; Lysons, R J; Trott, D J; Hampson, D J; Jones, P W; Morgan, J H

    1994-01-01

    Twelve intestinal spirochete strains of porcine origin were characterized on the basis of their phenotypic properties, by multilocus enzyme electrophoresis, and by pathogenicity testing in gnotobiotic pigs. The spirochetes used included two strains of Serpulina hyodysenteriae (B204 and P18A), two strains of Serpulina innocens (B256 and 4/71), one strain from the proposed new genus and species "Anguillina coli" (P43/6/78), and seven non-S. hyodysenteriae strains recently isolated from United K...

  3. Tropism and pathogenicity of rickettsiae

    Directory of Open Access Journals (Sweden)

    Tsuneo eUchiyama

    2012-06-01

    Full Text Available Rickettsiae are obligate intracellular parasitic bacteria that cause febrile exanthematous illnesses such as Rocky Mountain spotted fever, Mediterranean spotted fever, epidemic and murine typhus, etc. Although the vector ranges of each Rickettsia species are rather restricted; i.e., ticks belonging to Arachnida and lice and fleas belonging to Insecta usually act as vectors for spotted fever group and typhus group rickettsiae, respectively, it would be interesting to elucidate the mechanisms controlling the vector tropism of rickettsiae. This review discusses the factors determining the vector tropism of rickettsiae. In brief, the vector tropism of rickettsiae species is basically consistent with their tropism towards cultured tick and insect cells. The mechanisms responsible for rickettsiae pathogenicity are also described. Recently, genomic analyses of rickettsiae have revealed that they possess several genes that are homologous to those affecting the pathogenicity of other bacteria. Analyses comparing the genomes of pathogenic and nonpathogenic strains of rickettsiae have detected many factors that are related to rickettsial pathogenicity. It is also known that a reduction in the rickettsial genome has occurred during the course of its evolution. Interestingly, Rickettsia species with small genomes, such as Rickettsia prowazekii, are more pathogenic to humans than those with larger genomes. This review also examines the growth kinetics of pathogenic and nonpathogenic species of spotted fever group rickettsiae in mammalian cells. The growth of nonpathogenic species is restricted in these cells, which is mediated, at least in part, by autophagy. The superinfection of nonpathogenic rickettsiae-infected cells with pathogenic rickettsiae results in an elevated yield of the nonpathogenic rickettsiae and the growth of the pathogenic rickettsiae. Autophagy is restricted in these cells. These results are discussed in this review.

  4. Virulence Genes and Antibiotic Susceptibilities of Uropathogenic E. coli Strains.

    Science.gov (United States)

    Uzun, Cengiz; Oncül, Oral; Gümüş, Defne; Alan, Servet; Dayioğlu, Nurten; Küçüker, Mine Anğ

    2015-01-01

    The aim of this study is to detect the presence of and possible relation between virulence genes and antibiotic resistance in E. coli strains isolated from patients with acute, uncomplicated urinary tract infections (UTI). 62 E. coli strains isolated from patients with acute, uncomplicated urinary tract infections (50 strains isolated from acute uncomplicated cystitis cases (AUC); 12 strains from acute uncomplicated pyelonephritis cases (AUP)) were screened for virulence genes [pap (pyelonephritis-associated pili), sfa/foc (S and F1C fimbriae), afa (afimbrial adhesins), hly (hemolysin), cnf1 (cytotoxic necrotizing factor), aer (aerobactin), PAI (pathogenicity island marker), iroN (catecholate siderophore receptor), ompT (outer membrane protein T), usp (uropathogenic specific protein)] by PCR and for antimicrobial resistance by disk diffusion method according to CLSI criteria. It was found that 56 strains (90.3%) carried at least one virulence gene. The most common virulence genes were ompT (79%), aer (51.6%), PAI (51.6%) and usp (56.5%). 60% of the strains were resistant to at least one antibiotic. The highest resistance rates were against ampicillin (79%) and co-trimoxazole (41.9%). Fifty percent of the E. coli strains (31 strains) were found to be multiple resistant. Eight (12.9%) out of 62 strains were found to be ESBL positive. Statistically significant relationships were found between the absence of usp and AMP - SXT resistance, iroN and OFX - CIP resistance, PAI and SXT resistance, cnf1 and AMP resistance, and a significant relationship was also found between the presence of the afa and OFX resistance. No difference between E. coli strains isolated from two different clinical presentations was found in terms of virulence genes and antibiotic susceptibility.

  5. Genetic characterization of Anaplasma marginale strains from Tunisia using single and multiple gene typing reveals novel variants with an extensive genetic diversity.

    Science.gov (United States)

    Ben Said, Mourad; Ben Asker, Alaa; Belkahia, Hanène; Ghribi, Raoua; Selmi, Rachid; Messadi, Lilia

    2018-05-12

    Anaplasma marginale, which is responsible for bovine anaplasmosis in tropical and subtropical regions, is a tick-borne obligatory intraerythrocytic bacterium of cattle and wild ruminants. In Tunisia, information about the genetic diversity and the phylogeny of A. marginale strains are limited to the msp4 gene analysis. The purpose of this study is to investigate A. marginale isolates infecting 16 cattle located in different bioclimatic areas of northern Tunisia with single gene analysis and multilocus sequence typing methods on the basis of seven partial genes (dnaA, ftsZ, groEL, lipA, secY, recA and sucB). The single gene analysis confirmed the presence of different and novel heterogenic A. marginale strains infecting cattle from the north of Tunisia. The concatenated sequence analysis showed a phylogeographical resolution at the global level and that most of the Tunisian sequence types (STs) formed a separate cluster from a South African isolate and from all New World isolates and strains. By combining the characteristics of each single locus with those of the multi-loci scheme, these results provide a more detailed understanding on the diversity and the evolution of Tunisian A. marginale strains. Copyright © 2018 Elsevier GmbH. All rights reserved.

  6. Comparative Genomic Analyses of Multiple Pseudomonas Strains Infecting Corylus avellana Trees Reveal the Occurrence of Two Genetic Clusters with Both Common and Distinctive Virulence and Fitness Traits

    Science.gov (United States)

    Marcelletti, Simone; Scortichini, Marco

    2015-01-01

    The European hazelnut (Corylus avellana) is threatened in Europe by several pseudomonads which cause symptoms ranging from twig dieback to tree death. A comparison of the draft genomes of nine Pseudomonas strains isolated from symptomatic C. avellana trees was performed to identify common and distinctive genomic traits. The thorough assessment of genetic relationships among the strains revealed two clearly distinct clusters: P. avellanae and P. syringae. The latter including the pathovars avellanae, coryli and syringae. Between these two clusters, no recombination event was found. A genomic island of approximately 20 kb, containing the hrp/hrc type III secretion system gene cluster, was found to be present without any genomic difference in all nine pseudomonads. The type III secretion system effector repertoires were remarkably different in the two groups, with P. avellanae showing a higher number of effectors. Homologue genes of the antimetabolite mangotoxin and ice nucleation activity clusters were found solely in all P. syringae pathovar strains, whereas the siderophore yersiniabactin was only present in P. avellanae. All nine strains have genes coding for pectic enzymes and sucrose metabolism. By contrast, they do not have genes coding for indolacetic acid and anti-insect toxin. Collectively, this study reveals that genomically different Pseudomonas can converge on the same host plant by suppressing the host defence mechanisms with the use of different virulence weapons. The integration into their genomes of a horizontally acquired genomic island could play a fundamental role in their evolution, perhaps giving them the ability to exploit new ecological niches. PMID:26147218

  7. Typing and Evaluation of the Genetic Relatedness of Listeria monocytogenes Strains Isolated from Food Samples by the Multiple-Locus Variable number Tandem Repeat Analysis (MLVA

    Directory of Open Access Journals (Sweden)

    Behrooz Sadeghi kalani

    2014-12-01

    Full Text Available Background and Aim:Listeria monocytogenes cause listeriosis and fatal infections in humans. The aim of this study was typing and evaluation of the genetic relatedness of L. monocytogenes strains from food samples using MLVA technique. Materials and Methods: 317 food samples were collected from 2009 to 2013 in Tehran,Iran. After final diagnosis of L. monocytogenes DNA was extracted to perform of MLVA technique, and also PCR products were analyzed by Gene Tools software. The number of tandem repeats was determined by using special equation for each selected locus. Also typing of strains was done. Results: 24 samples of 317 food samples were positive for L. monocytogenes using standard laboratory techniques. A total 13 different types were determined by MLVA technique that type 2 and type 3 were the most abundant types by 6 and 4 strains, respectively. Conclusions: The results of this study showed the presence of L. monocytogenes in dairy products and meat samples, therefore all people, especially pregnant women should observe health tips when using these products. The results of typing showed that L. monocytogenes strains from different sources can have the same origin. MLVA technique is easy with high accuracy and this method can be used in typing and evaluation of the genetic relatedness of L. monocytogenes for determination the source of contamination.

  8. Temporal dynamics of the developing lung transcriptome in three common inbred strains of laboratory mice reveals multiple stages of postnatal alveolar development

    Directory of Open Access Journals (Sweden)

    Kyle J. Beauchemin

    2016-08-01

    Full Text Available To characterize temporal patterns of transcriptional activity during normal lung development, we generated genome wide gene expression data for 26 pre- and post-natal time points in three common inbred strains of laboratory mice (C57BL/6J, A/J, and C3H/HeJ. Using Principal Component Analysis and least squares regression modeling, we identified both strain-independent and strain-dependent patterns of gene expression. The 4,683 genes contributing to the strain-independent expression patterns were used to define a murine Developing Lung Characteristic Subtranscriptome (mDLCS. Regression modeling of the Principal Components supported the four canonical stages of mammalian embryonic lung development (embryonic, pseudoglandular, canalicular, saccular defined previously by morphology and histology. For postnatal alveolar development, the regression model was consistent with four stages of alveolarization characterized by episodic transcriptional activity of genes related to pulmonary vascularization. Genes expressed in a strain-dependent manner were enriched for annotations related to neurogenesis, extracellular matrix organization, and Wnt signaling. Finally, a comparison of mouse and human transcriptomics from pre-natal stages of lung development revealed conservation of pathways associated with cell cycle, axon guidance, immune function, and metabolism as well as organism-specific expression of genes associated with extracellular matrix organization and protein modification. The mouse lung development transcriptome data generated for this study serves as a unique reference set to identify genes and pathways essential for normal mammalian lung development and for investigations into the developmental origins of respiratory disease and cancer. The gene expression data are available from the Gene Expression Omnibus (GEO archive (GSE74243. Temporal expression patterns of mouse genes can be investigated using a study specific web resource (http://lungdevelopment.jax.org.

  9. Temporal dynamics of the developing lung transcriptome in three common inbred strains of laboratory mice reveals multiple stages of postnatal alveolar development.

    Science.gov (United States)

    Beauchemin, Kyle J; Wells, Julie M; Kho, Alvin T; Philip, Vivek M; Kamir, Daniela; Kohane, Isaac S; Graber, Joel H; Bult, Carol J

    2016-01-01

    To characterize temporal patterns of transcriptional activity during normal lung development, we generated genome wide gene expression data for 26 pre- and post-natal time points in three common inbred strains of laboratory mice (C57BL/6J, A/J, and C3H/HeJ). Using Principal Component Analysis and least squares regression modeling, we identified both strain-independent and strain-dependent patterns of gene expression. The 4,683 genes contributing to the strain-independent expression patterns were used to define a murine Developing Lung Characteristic Subtranscriptome (mDLCS). Regression modeling of the Principal Components supported the four canonical stages of mammalian embryonic lung development (embryonic, pseudoglandular, canalicular, saccular) defined previously by morphology and histology. For postnatal alveolar development, the regression model was consistent with four stages of alveolarization characterized by episodic transcriptional activity of genes related to pulmonary vascularization. Genes expressed in a strain-dependent manner were enriched for annotations related to neurogenesis, extracellular matrix organization, and Wnt signaling. Finally, a comparison of mouse and human transcriptomics from pre-natal stages of lung development revealed conservation of pathways associated with cell cycle, axon guidance, immune function, and metabolism as well as organism-specific expression of genes associated with extracellular matrix organization and protein modification. The mouse lung development transcriptome data generated for this study serves as a unique reference set to identify genes and pathways essential for normal mammalian lung development and for investigations into the developmental origins of respiratory disease and cancer. The gene expression data are available from the Gene Expression Omnibus (GEO) archive (GSE74243). Temporal expression patterns of mouse genes can be investigated using a study specific web resource (http://lungdevelopment.jax.org).

  10. Pathogenicity of Human ST23 Streptococcus agalactiae to Fish and Genomic Comparison of Pathogenic and Non-pathogenic Isolates

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2017-10-01

    Full Text Available Streptococcus agalactiae, or Group B Streptococcus (GBS, is a major pathogen causing neonatal sepsis and meningitis, bovine mastitis, and fish meningoencephalitis. CC23, including its namesake ST23, is not only the predominant GBS strain derived from human and cattle, but also can infect a variety of homeothermic and poikilothermic species. However, it has never been characterized in fish. This study aimed to determine the pathogenicity of ST23 GBS to fish and explore the mechanisms causing the difference in the pathogenicity of ST23 GBS based on the genome analysis. Infection of tilapia with 10 human-derived ST23 GBS isolates caused tissue damage and the distribution of pathogens within tissues. The mortality rate of infection was ranged from 76 to 100%, and it was shown that the mortality rate caused by only three human isolates had statistically significant difference compared with fish-derived ST7 strain (P < 0.05, whereas the mortality caused by other seven human isolates did not show significant difference compared with fish-derived ST7 strain. The genome comparison and prophage analysis showed that the major genome difference between virulent and non-virulent ST23 GBS was attributed to the different prophage sequences. The prophage in the P1 region contained about 43% GC and encoded 28–39 proteins, which can mediate the acquisition of YafQ/DinJ structure for GBS by phage recombination. YafQ/DinJ belongs to one of the bacterial toxin–antitoxin (TA systems and allows cells to cope with stress. The ST23 GBS strains carrying this prophage were not pathogenic to tilapia, but the strains without the prophage or carrying the pophage that had gene mutation or deletion, especially the deletion of YafQ/DinJ structure, were highly pathogenic to tilapia. In conclusion, human ST23 GBS is highly pathogenic to fish, which may be related to the phage recombination.

  11. Digital PCR for detection of citrus pathogens

    Science.gov (United States)

    Citrus trees are often infected with multiple pathogens of economic importance, especially those with insect or mite vectors. Real-time/quantitative PCR (qPCR) has been used for high-throughput detection and relative quantification of pathogens; however, target reference or standards are required. I...

  12. Genome-wide comparison and taxonomic relatedness of multiple Xylella fastidiosa strains reveal the occurrence of three subspecies and a new Xylella species.

    Science.gov (United States)

    Marcelletti, Simone; Scortichini, Marco

    2016-10-01

    A total of 21 Xylella fastidiosa strains were assessed by comparing their genomes to infer their taxonomic relationships. The whole-genome-based average nucleotide identity and tetranucleotide frequency correlation coefficient analyses were performed. In addition, a consensus tree based on comparisons of 956 core gene families, and a genome-wide phylogenetic tree and a Neighbor-net network were constructed with 820,088 nucleotides (i.e., approximately 30-33 % of the entire X. fastidiosa genome). All approaches revealed the occurrence of three well-demarcated genetic clusters that represent X. fastidiosa subspecies fastidiosa, multiplex and pauca, with the latter appeared to diverge. We suggest that the proposed but never formally described subspecies 'sandyi' and 'morus' are instead members of the subspecies fastidiosa. These analyses support the view that the Xylella strain isolated from Pyrus pyrifolia in Taiwan is likely to be a new species. A widely used multilocus sequence typing analysis yielded conflicting results.

  13. Clostridium difficile outbreak caused by NAP1/BI/027 strain and non-027 strains in a Mexican hospital

    Directory of Open Access Journals (Sweden)

    Rayo Morfin-Otero

    2016-01-01

    Conclusions: C. difficile NAP1/BI/027 strain and non-027 strains are established pathogens in our hospital. Accordingly, surveillance of C. difficile infections is now part of our nosocomial prevention program.

  14. Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli

    Science.gov (United States)

    Blum, Shlomo E.; Heller, Elimelech D.; Sela, Shlomo; Elad, Daniel; Edery, Nir; Leitner, Gabriel

    2015-01-01

    Escherichia coli is a major etiological agent of intra-mammary infections (IMI) in cows, leading to acute mastitis and causing great economic losses in dairy production worldwide. Particular strains cause persistent IMI, leading to recurrent mastitis. Virulence factors of mammary pathogenic E. coli (MPEC) involved pathogenesis of mastitis as well as those differentiating strains causing acute or persistent mastitis are largely unknown. This study aimed to identify virulence markers in MPEC through whole genome and phenome comparative analysis. MPEC strains causing acute (VL2874 and P4) or persistent (VL2732) mastitis were compared to an environmental strain (K71) and to the genomes of strains representing different E. coli pathotypes. Intra-mammary challenge in mice confirmed experimentally that the strains studied here have different pathogenic potential, and that the environmental strain K71 is non-pathogenic in the mammary gland. Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes. Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism. Features associated with cytotoxicity or intra-cellular survival were found specifically in the genomes of strains from severe and acute (VL2874) or persistent (VL2732) mastitis, respectively. MPEC genomes were relatively similar to strain K-12, which was subsequently shown here to be possibly pathogenic in the mammary gland. Phenome analysis showed that the persistent MPEC was the most versatile in terms of nutrients metabolized and acute MPEC the least. Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism. This study

  15. Genomic Microbial Epidemiology Is Needed to Comprehend the Global Problem of Antibiotic Resistance and to Improve Pathogen Diagnosis.

    Science.gov (United States)

    Wyrsch, Ethan R; Roy Chowdhury, Piklu; Chapman, Toni A; Charles, Ian G; Hammond, Jeffrey M; Djordjevic, Steven P

    2016-01-01

    Contamination of waste effluent from hospitals and intensive food animal production with antimicrobial residues is an immense global problem. Antimicrobial residues exert selection pressures that influence the acquisition of antimicrobial resistance and virulence genes in diverse microbial populations. Despite these concerns there is only a limited understanding of how antimicrobial residues contribute to the global problem of antimicrobial resistance. Furthermore, rapid detection of emerging bacterial pathogens and strains with resistance to more than one antibiotic class remains a challenge. A comprehensive, sequence-based genomic epidemiological surveillance model that captures essential microbial metadata is needed, both to improve surveillance for antimicrobial resistance and to monitor pathogen evolution. Escherichia coli is an important pathogen causing both intestinal [intestinal pathogenic E. coli (IPEC)] and extraintestinal [extraintestinal pathogenic E. coli (ExPEC)] disease in humans and food animals. ExPEC are the most frequently isolated Gram negative pathogen affecting human health, linked to food production practices and are often resistant to multiple antibiotics. Cattle are a known reservoir of IPEC but they are not recognized as a source of ExPEC that impact human or animal health. In contrast, poultry are a recognized source of multiple antibiotic resistant ExPEC, while swine have received comparatively less attention in this regard. Here, we review what is known about ExPEC in swine and how pig production contributes to the problem of antibiotic resistance.

  16. Optical properties of a-plane (Al, Ga)N/GaN multiple quantum wells grown on strain engineered Zn1-xMgxO layers by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Xia, Y.; Vinter, B.; Chauveau, J.-M.; Brault, J.; Nemoz, M.; Teisseire, M.; Leroux, M.

    2011-01-01

    Nonpolar (1120) Al 0.2 Ga 0.8 N/GaN multiple quantum wells (MQWs) have been grown by molecular beam epitaxy on (1120) Zn 0.74 Mg 0.26 O templates on r-plane sapphire substrates. The quantum wells exhibit well-resolved photoluminescence peaks in the ultra-violet region, and no sign of quantum confined Stark effect is observed in the complete multiple quantum well series. The results agree well with flat band quantum well calculations. Furthermore, we show that the MQW structures are strongly polarized along the [0001] direction. The origin of the polarization is discussed in terms of the strain anisotropy dependence of the exciton optical oscillator strengths.

  17. Emerging Pathogens Initiative (EPI)

    Data.gov (United States)

    Department of Veterans Affairs — The Emerging Pathogens Initiative (EPI) database contains emerging pathogens information from the local Veterans Affairs Medical Centers (VAMCs). The EPI software...

  18. [Human plague and pneumonic plague : pathogenicity, epidemiology, clinical presentations and therapy].

    Science.gov (United States)

    Riehm, Julia M; Löscher, Thomas

    2015-07-01

    Yersinia pestis is a highly pathogenic gram-negative bacterium and the causative agent of human plague. In the last 1500 years and during three dreaded pandemics, millions of people became victims of Justinian's plague, the Black Death, or modern plague. Today, Y. pestis is endemic in natural foci of Asian, African and American countries. Due to its broad dissemination in mammal species and fleas, eradication of the pathogen will not be possible in the near future. In fact, plague is currently classified as a "re-emerging disease". Infection may occur after the bite of an infected flea, but also after oral ingestion or inhalation of the pathogen. The clinical presentations comprise the bubonic and pneumonic form, septicemia, rarely pharyngitis, and meningitis. Most human cases can successfully be treated with antibiotics. However, the high transmission rate and lethality of pneumonic plague require international and mandatory case notification and quarantine of patients. Rapid diagnosis, therapy and barrier nursing are not only crucial for the individual patient but also for the prevention of further spread of the pathogen or of epidemics. Therefore, WHO emergency schedules demand the isolation of cases, identification and surveillance of contacts as well as control of zoonotic reservoir animals and vectors. These sanctions and effective antibiotic treatment usually allow a rapid containment of outbreaks. However, multiple antibiotic resistant strains of Y. pestis have been isolated from patients in the past. So far, no outbreaks with such strains have been reported.

  19. Isolation of TDA-producing Phaeobacter strains from sea bass larval rearing units and their probiotic effect against pathogenic Vibrio spp. in Artemia cultures

    DEFF Research Database (Denmark)

    Grotkjær, Torben; Bentzon-Tilia, Mikkel; D'Alvise, Paul

    2016-01-01

    V. harveyi, which is the major bacterial pathogen in crustaceans and Mediterranean sea bass larvae cultures. Concomitantly, they significantly improved survival of V. harveyi-infected brine shrimp. 16S rRNA gene sequence homology identified the antagonists as Phaeobacter sp., and in silico DNA...... Vibrio anguillarum and reduce mortality in V. anguillarum-infected cod and turbot larvae. In this study, it was demonstrated that antagonistic Roseobacter-clade bacteria could be isolated from sea bass larval rearing units. In addition, it was shown that they not only antagonized V. anguillarum but also......-producing Phaeobacter isolated from Mediterranean marine larviculture are promising probiotic bacteria against pathogenic Vibrio in crustacean live-feed cultures for marine fish larvae....

  20. Characterisation of Yersinia Secretion Apparatus--Pathogenicity Island (Ysa-PI) of Yersinia enterocolitica 1B/O8 in Poland: an Idle Ysa is a Specific Hallmark of the Epidemic Sensu Stricto Strain.

    Science.gov (United States)

    Wołkowicz, Tomasz; Zacharczuk, Katarzyna; Rokosz-Chudziak, Natalia; Rastawicki, Waldemar; Gierczyński, Rafał

    2015-01-01

    Yersinia secretion apparatus (Ysa), the chromosomal type three secretion system (T3SS) is considered to contribute to virulence of high-pathogenicity Yersina enterocolitica biovar 1B. DNA-sequence of Ysa pathogenicity island was determined for clinical isolate DM0110 of Y enterocolitica 1B/08 with origin in Poland. We found a premature stop-codon in the regulatory gene ysrR (mutation at position 269). Altered ysrR was detected in all tested 78 isolates of Y enterocolitica 1B/O8 collected from clinical samples in Poland from 2004 to 2013. Since aberrations in YsrR are considered to inactivate Ysa, our findings may suggest Ysa is not indispensable for Y enterocolitica 1B/O8 to infect humans.

  1. Associations between Mycobacterium tuberculosis Strains and Phenotypes

    Science.gov (United States)

    Brown, Timothy; Nikolayevskyy, Vladyslav; Velji, Preya

    2010-01-01

    To inform development of tuberculosis (TB) control strategies, we characterized a total of 2,261 Mycobacterium tuberculosis complex isolates by using multiple phenotypic and molecular markers, including polymorphisms in repetitive sequences (spoligotyping and variable-number tandem repeats [VNTRs]) and large sequence and single-nucleotide polymorphisms. The Beijing family was strongly associated with multidrug resistance (p = 0.0001), and VNTR allelic variants showed strong associations with spoligotyping families: >5 copies at exact tandem repeat (ETR) A, >2 at mycobacterial interspersed repetitive unit 24, and >3 at ETR-B associated with the East African–Indian and M. bovis strains. All M. tuberculosis isolates were differentiated into 4 major lineages, and a maximum parsimony tree was constructed suggesting a more complex phylogeny for M. africanum. These findings can be used as a model of pathogen global diversity. PMID:20113558

  2. Mechanism of mercuric chloride resistance in microorganisms. II. NADPH-dependent reduction of mercuric chloride and vaporization of mercury from mercuric chloride by a multiple drug resistant strain of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Komura, I; Funaba, T; Izaki, K

    1971-01-01

    The activity to vaporize a /sup 203/Hg compound from /sup 203/HgCl/sub 2/ was demonstrated in crude cell-free extracts of a strain of Escherichia coli W2252, which had acquired the multiple drug resistance. NADPH was essential for the vaporization, while NADH had only a slight stimulating effect and NADP/sup +/ had no effect. The oxidation of NADPH dependent on HgCl/sub 2/ was also demonstrated in the crude extracts, but the HgCl/sub 2/-dependent NADH oxidation could be demonstrated only when a partially purified enzyme preparation was used. The rate of NADH oxidation was much slower than that of NADPH oxidation. It was concluded that NADPH, and to a lesser extent NADH, act as electron donors for the enzymatic reduction of HgCl/sub 2/ and the vaporization occurs after this reduction. This reduction and subsequent vaporization seem to provide a mechanism of resistance to HgCl/sub 2/ in E. coli strains having the multiple drug resistance. 15 references, 4 figures, 4 tables.

  3. Draft Genome Sequence of Pseudomonas sp. Strain Ep R1 Isolated from Echinacea purpurea Roots and Effective in the Growth Inhibition of Human Opportunistic Pathogens Belonging to the Burkholderia cepacia Complex.

    Science.gov (United States)

    Maggini, Valentina; Presta, Luana; Miceli, Elisangela; Fondi, Marco; Bosi, Emanuele; Chiellini, Carolina; Fagorzi, Camilla; Bogani, Patrizia; Di Pilato, Vincenzo; Rossolini, Gian Maria; Mengoni, Alessio; Firenzuoli, Fabio; Perrin, Elena; Fani, Renato

    2017-05-18

    In this announcement, we detail the draft genome sequence of the Pseudomonas sp. strain Ep R1, isolated from the roots of the medicinal plant Echinacea purpurea The elucidation of this genome sequence may allow the identification of genes associated with the production of antimicrobial compounds. Copyright © 2017 Maggini et al.

  4. Insights into the evolution of pathogenicity of Escherichia coli from genomic analysis of intestinal E. coli of Marmota himalayana in Qinghai-Tibet plateau of China.

    Science.gov (United States)

    Lu, Shan; Jin, Dong; Wu, Shusheng; Yang, Jing; Lan, Ruiting; Bai, Xiangning; Liu, Sha; Meng, Qiong; Yuan, Xuejiao; Zhou, Juan; Pu, Ji; Chen, Qiang; Dai, Hang; Hu, Yuanyuan; Xiong, Yanwen; Ye, Changyun; Xu, Jianguo

    2016-12-07

    Escherichia coli is both of a widespread harmless gut commensal and a versatile pathogen of humans. Domestic animals are a well-known reservoir for pathogenic E. coli. However, studies of E. coli populations from wild animals that have been separated from human activities had been very limited. Here we obtained 580 isolates from intestinal contents of 116 wild Marmot Marmota himalayana from Qinghai-Tibet plateau, China, with five isolates per animal. We selected 125 (hereinafter referred to as strains) from the 580 isolates for genome sequencing, based on unique pulse field gel electrophoresis patterns and at least one isolate per animal. Whole genome sequence analysis revealed that all 125 strains carried at least one and the majority (79.2%) carried multiple virulence genes based on the analysis of 22 selected virulence genes. In particular, the majority of the strains carried virulence genes from different pathovars as potential 'hybrid pathogens'. The alleles of eight virulence genes from the Marmot E. coli were found to have diverged earlier than all known alleles from human and other animal E. coli. Phylogenetic analysis of the 125 Marmot E. coli genomes and 355 genomes selected from 1622 human and other E. coli strains identified two new phylogroups, G and H, both of which diverged earlier than the other phylogroups. Eight of the 12 well-known pathogenic E. coli lineages were found to share a most recent common ancestor with one or more Marmot E. coli strains. Our results suggested that the intestinal E. coli of the Marmots contained a diverse virulence gene pool and is potentially pathogenic to humans. These findings provided a new understanding of the evolutionary origin of pathogenic E. coli.

  5. Pathogenicity of Shigella in chickens.

    Science.gov (United States)

    Shi, Run; Yang, Xia; Chen, Lu; Chang, Hong-tao; Liu, Hong-ying; Zhao, Jun; Wang, Xin-wei; Wang, Chuan-qing

    2014-01-01

    Shigellosis in chickens was first reported in 2004. This study aimed to determine the pathogenicity of Shigella in chickens and the possibility of cross-infection between humans and chickens. The pathogenicity of Shigella in chickens was examined via infection of three-day-old SPF chickens with Shigella strain ZD02 isolated from a human patient. The virulence and invasiveness were examined by infection of the chicken intestines and primary chicken intestinal epithelial cells. The results showed Shigella can cause death via intraperitoneal injection in SPF chickens, but only induce depression via crop injection. Immunohistochemistry and transmission electron microscopy revealed the Shigella can invade the intestinal epithelia. Immunohistochemistry of the primary chicken intestinal epithelial cells infected with Shigella showed the bacteria were internalized into the epithelial cells. Electron microscopy also confirmed that Shigella invaded primary chicken intestinal epithelia and was encapsulated by phagosome-like membranes. Our data demonstrate that Shigella can invade primary chicken intestinal epithelial cells in vitro and chicken intestinal mucosa in vivo, resulting in pathogenicity and even death. The findings suggest Shigella isolated from human or chicken share similar pathogenicity as well as the possibility of human-poultry cross-infection, which is of public health significance.

  6. Multiple sclerosis

    DEFF Research Database (Denmark)

    Stenager, Egon; Stenager, E N; Knudsen, Lone

    1994-01-01

    In a cross-sectional study of 117 randomly selected patients (52 men, 65 women) with definite multiple sclerosis, it was found that 76 percent were married or cohabitant, 8 percent divorced. Social contacts remained unchanged for 70 percent, but outgoing social contacts were reduced for 45 percent......, need for structural changes in home and need for pension became greater with increasing physical handicap. No significant differences between gender were found. It is concluded that patients and relatives are under increased social strain, when multiple sclerosis progresses to a moderate handicap...

  7. Invasion of Porphyromonas gingivalis strains into vascular cells and tissue

    Directory of Open Access Journals (Sweden)

    Ingar Olsen

    2015-08-01

    Full Text Available Porphyromonas gingivalis is considered a major pathogen in adult periodontitis and is also associated with multiple systemic diseases, for example, cardiovascular diseases. One of its most important virulence factors is invasion of host cells. The invasion process includes attachment, entry/internalization, trafficking, persistence, and exit. The present review discusses these processes related to P. gingivalis in cardiovascular cells and tissue. Although most P. gingivalis strains invade, the invasion capacity of strains and the mechanisms of invasion including intracellular trafficking among them differ. This is consistent with the fact that there are significant differences in the pathogenicity of P. gingivalis strains. P. gingivalis invasion mechanisms are also dependent on types of host cells. Although much is known about the invasion process of P. gingivalis, we still have little knowledge of its exit mechanisms. Nevertheless, it is intriguing that P. gingivalis can remain viable in human cardiovascular cells and atherosclerotic plaque and later exit and re-enter previously uninfected host cells.

  8. Immunization with 60 kD Ro peptide produces different stages of preclinical autoimmunity in a Sjögren's syndrome model among multiple strains of inbred mice.

    Science.gov (United States)

    Kurien, B T; Dsouza, A; Igoe, A; Lee, Y J; Maier-Moore, J S; Gordon, T; Jackson, M; Scofield, R H

    2013-07-01

    Sjögren's syndrome is a chronic illness manifested characteristically by immune injury to the salivary and lacrimal glands, resulting in dry mouth/eyes. Anti-Ro [Sjögren's syndrome antigen A (SSA)] and anti-La [Sjögren's syndrome antigen B (SSB)] autoantibodies are found frequently in Sjögren's subjects as well as in individuals who will go on to develop the disease. Immunization of BALB/c mice with Ro60 peptides results in epitope spreading with anti-Ro and anti-La along with lymphocyte infiltration of salivary glands similar to human Sjögren's. In addition, these animals have poor salivary function/low saliva volume. In this study, we examined whether Ro-peptide immunization produces a Sjögren's-like illness in other strains of mice. BALB/c, DBA-2, PL/J, SJL/J and C57BL/6 mice were immunized with Ro60 peptide-274. Sera from these mice were studied by immunoblot and enzyme-linked immunosorbent assay for autoantibodies. Timed salivary flow was determined after pharmacological stimulation, and salivary glands were examined pathologically. We found that SJL/J mice had no immune response to the peptide from Ro60, while C57BL/6 mice produced antibodies that bound the peptide but had no epitope spreading. PL/J mice had epitope spreading to other structures of Ro60 as well as to La, but like C57BL/6 and SJL/J had no salivary gland lymphocytic infiltration and no decrement of salivary function. DBA-2 and BALB/c mice had infiltration but only BALB/c had decreased salivary function. The immunological processes leading to a Sjögren's-like illness after Ro-peptide immunization were interrupted in a stepwise fashion in these differing mice strains. These data suggest that this is a model of preclinical disease with genetic control for epitope spreading, lymphocytic infiltration and glandular dysfunction. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  9. Comparative Radiosensitivity of Pathogenic Bacteria and Viruses

    International Nuclear Information System (INIS)

    Ghys, R.; Vandergoten, R.; Paquette, J.-C.; Fredette, V.; Plante, C.; Pavilanis, V.; Gilker, J.-C.

    1967-01-01

    The authors exposed to gamma rays from a MCo source (''Gammacell 220'' from Atomic Energy of Canada, Ltd.) various pathogenic micro-organisms: a slow-growing aerobic bacterium (Mycobacterium tuberculosis, 10 varieties of the strain B. C. G.), a fast-growing anaerobic bacterium (Clostridium perfringens, strain SWG-121) and 4 strains of influenza virus (2 from group A and 2 from group B). In the case of B. C. G., an LD 90 of 29 ± 1 kR is reported for bacilli irradiated immediately before subculture and subsequently cultivated for at most 14 days. If the microbes are cultivated for 28 days, the yield from cultures after exposures of up to 50 kR is at least equal to that of control specimens; it then decreases rapidly, and a dose of 140 kR inhibits bacterial growth completely. It is reported that the LD 90 of the strain of Cl. perfringens used in the study is very much dependent on die culture conditions and die conditions under which die microbe growth measurements are made; 24 h after irradiation it is at least 1 MR. Although no spores are seen in the microscope, this would seem to demonstrate the presence in the cultures of extremely radioresistant sporulated individuals. Group A influenza viruses are found to be more radioresistant than those of group B. The LD 90 of relatively low radiation doses varies between 75 and 100 kR, and is higher if irradiation is performed at -78.5°C. It is very difficult to inactivate the last virus particles; multiplicity reactivation seems to occur in certain experimental conditions. Haemagglutinant activity does not vary, even after die highest exposures used (4 MR). Two important practical conclusions are drawn: (1) The use of a single dose (e. g. 2.5 Mrad) for radiosterilization gives an exposure which is unnecessarily high in some cases and insufficient in others, and (2) Selective radiosterilization is sometimes possible: the viability of a micro-organism used, for example, to produce a vaccine may not be

  10. SILAC-based comparative analysis of pathogenic Escherichia coli secretomes

    DEFF Research Database (Denmark)

    Boysen, Anders; Borch, Jonas; Krogh, Thøger Jensen

    2015-01-01

    Comparative studies of pathogenic bacteria and their non-pathogenic counterparts has led to the discovery of important virulence factors thereby generating insight into mechanisms of pathogenesis. Protein-based antigens for vaccine development are primarily selected among unique virulence...... experimental approach. In addition we find proteins that are not unique to the pathogenic strains but expressed at levels different from the commensal strain, including the colonization factor YghJ and the surface adhesin antigen 43, which is involved in pathogenesis of other Gram-negative bacteria......-related factors produced by the pathogen of interest. However, recent work indicates that proteins that are not unique to the pathogen but instead selectively expressed compared to its non-pathogenic counterpart could also be vaccine candidates or targets for drug development. Modern methods in quantitative...

  11. Pseudomnas syringae – a Pathogen of Fruit Trees in Serbia

    Directory of Open Access Journals (Sweden)

    Veljko Gavrilović

    2009-01-01

    Full Text Available Data about symptomatology, pathogenicity and bacteriological characteristics of Pseudomonas syringae, and PCR methods for fast and reliable detection of the pathogen are given in this paper. P. syringae has been experimentaly proved as a pathogen of pear, apple, apricot, plum cherry, and raspberry, and pathogen strains have also been isolated from necrotic peach buds. Two pathogen varieties, syringae and morsprunorum, were found in our research in Serbia, the former being dominant on fruit trees.The most reliable method for detection of this bacteria is PCR, using BOX and REP primers. This method has also revealed significant differences among the strains originating from fruit trees in Serbia. Thus, it was proved that the population of P. syringae in Serbia is heterogeneous, which is very important for future epidemiologocal studies. Control of this pathogen includes mechanical, cultural and chemical measures, but integrated approach is very important for sustainable control.

  12. New trends in emerging pathogens.

    Science.gov (United States)

    Skovgaard, Niels

    2007-12-15

    The emergence of pathogens is the result of a number of impact in all parts of the food chain. The emerging technologies in food production explain how new pathogens can establish themselves in the food chain and compromise food safety. The impact of the food technology is analysed for several bacteria, such as Yersinia, Campylobacter, Arcobacter, Helicobacter pullorum, Enterobacter sakazakii, Mycobacterium avium spp. paratuberculosis, prions related to vCJD and others. The importance of the ability of many microbes to form VBNC forms is elaborated on. Research on culture independent methods may