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Sample records for antimicrobial peptide-like genes

  1. Uses of antimicrobial genes from microbial genome

    Science.gov (United States)

    Sorek, Rotem; Rubin, Edward M.

    2013-08-20

    We describe a method for mining microbial genomes to discover antimicrobial genes and proteins having broad spectrum of activity. Also described are antimicrobial genes and their expression products from various microbial genomes that were found using this method. The products of such genes can be used as antimicrobial agents or as tools for molecular biology.

  2. A plant natriuretic peptide-like gene in the bacterial pathogen Xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry

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    Sayed Muhammed

    2004-03-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. PNPs are up-regulated under conditions of osmotic stress and PNP-dependent processes include changes in ion transport and increases of H2O uptake into protoplasts and whole tissue. Presentation of the hypothesis The bacterial citrus pathogen Xanthomonas axonopodis pv. Citri str. 306 contains a gene encoding a PNP-like protein. We hypothesise that this bacterial protein can alter plant cell homeostasis and thus is likely to represent an example of molecular mimicry that enables the pathogen to manipulate plant responses in order to bring about conditions favourable to the pathogen such as the induced plant tissue hyper-hydration seen in the wet edged lesions associated with Xanthomonas axonopodis infection. Testing the hypothesis We found a Xanthomonas axonopodis PNP-like protein that shares significant sequence similarity and identical domain organisation with PNPs. We also observed a significant excess of conserved residues between the two proteins within the domain previously identified as being sufficient to induce biological activity. Structural modelling predicts identical six stranded double-psi β barrel folds for both proteins thus supporting the hypothesis of similar modes of action. No significant similarity between the Xanthomonas axonopodis protein and other bacterial proteins from GenBank was found. Sequence similarity of the Xanthomonas axonopodis PNP-like protein with the Arabidopsis thaliana PNP (AtPNP-A, shared domain organisation and incongruent phylogeny suggest that the PNP-gene may have been acquired by the bacteria in an ancient lateral gene transfer event. Finally, activity of a recombinant Xanthomonas axonopodis protein in plant tissue and changes in symptoms induced by a Xanthomonas axonopodis mutant with a knocked-out PNP-like gene will be experimental proof of molecular mimicry

  3. Identification of acquired antimicrobial resistance genes

    DEFF Research Database (Denmark)

    Zankari, Ea; Hasman, Henrik; Cosentino, Salvatore;

    2012-01-01

    ObjectivesIdentification of antimicrobial resistance genes is important for understanding the underlying mechanisms and the epidemiology of antimicrobial resistance. As the costs of whole-genome sequencing (WGS) continue to decline, it becomes increasingly available in routine diagnostic laborato......ObjectivesIdentification of antimicrobial resistance genes is important for understanding the underlying mechanisms and the epidemiology of antimicrobial resistance. As the costs of whole-genome sequencing (WGS) continue to decline, it becomes increasingly available in routine diagnostic...... laboratories and is anticipated to substitute traditional methods for resistance gene identification. Thus, the current challenge is to extract the relevant information from the large amount of generated data.MethodsWe developed a web-based method, ResFinder that uses BLAST for identification of acquired...... antimicrobial resistance genes in whole-genome data. As input, the method can use both pre-assembled, complete or partial genomes, and short sequence reads from four different sequencing platforms. The method was evaluated on 1862 GenBank files containing 1411 different resistance genes, as well as on 23 de...

  4. The Sulfolobicin Genes of Sulfolobus acidocaldarius Encode Novel Antimicrobial Proteins

    NARCIS (Netherlands)

    Ellen, Albert F.; Rohulya, Olha V.; Fusetti, Fabrizia; Wagner, Michaela; Albers, Sonja-Verena; Driessen, Arnold J. M.

    2011-01-01

    Crenarchaea, such as Sulfolobus acidocaldarius and Sulfolobus tokodaii, produce antimicrobial proteins called sulfolobicins. These antimicrobial proteins inhibit the growth of closely related species. Here we report the identification of the sulfolobicin-encoding genes in S. acidocaldarius. The acti

  5. Associations between Antimicrobial Resistance Phenotypes, Antimicrobial Resistance Genes, and Virulence Genes of Fecal Escherichia coli Isolates from Healthy Grow-Finish Pigs ▿

    OpenAIRE

    2009-01-01

    Escherichia coli often carries linked antimicrobial resistance genes on transmissible genetic elements. Through coselection, antimicrobial use may select for unrelated but linked resistance or virulence genes. This study used unconditional statistical associations to investigate the relationships between antimicrobial resistance phenotypes and antimicrobial resistance genes in 151 E. coli isolates from healthy pigs. Phenotypic resistance to each drug was significantly associated with phenotyp...

  6. The sulfolobicin genes of Sulfolobus acidocaldarius encode novel antimicrobial proteins.

    Science.gov (United States)

    Ellen, Albert F; Rohulya, Olha V; Fusetti, Fabrizia; Wagner, Michaela; Albers, Sonja-Verena; Driessen, Arnold J M

    2011-09-01

    Crenarchaea, such as Sulfolobus acidocaldarius and Sulfolobus tokodaii, produce antimicrobial proteins called sulfolobicins. These antimicrobial proteins inhibit the growth of closely related species. Here we report the identification of the sulfolobicin-encoding genes in S. acidocaldarius. The active sulfolobicin comprises two proteins that are equipped with a classical signal sequence. These proteins are secreted by the cells and found to be membrane vesicle associated. Gene inactivation studies demonstrate that both proteins are required for the bacteriostatic antimicrobial activity. Sulfolobicins constitute a novel class of antimicrobial proteins without detectable homology to any other protein.

  7. Occurrence of antimicrobials and antimicrobial resistance genes in beef cattle storage ponds and swine treatment lagoons

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    Zhang, Yuping; Zhang, Chiqian [Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE (United States); Parker, David B. [USDA Meat Animal Research Center, Clay Center, NE (United States); Snow, Daniel D. [Water Sciences Laboratory, University of Nebraska-Lincoln, Lincoln, NE (United States); Zhou, Zhi [Department of Civil and Environmental Engineering, National University of Singapore (Singapore); Li, Xu, E-mail: xuli@unl.edu [Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE (United States)

    2013-10-01

    Livestock manure treatment and storage structures are potential environmental sources of antimicrobials and antimicrobial resistance genes (ARGs). In this study, the occurrence of antimicrobials and ARGs was investigated in the water and the sludge compartments of beef cattle storage ponds and swine lagoons. Analysis was focused on two families of antimicrobials (sulfonamide and tetracycline) and the corresponding ARGs (sul1, sul2, tetO, tetQ and tetX). Results showed that the pseudo-partitioning coefficients of tetracyclines were higher than those of sulfonamides, suggesting different distributions of these two classes of antimicrobials between water and sludge. The ARGs tested were detected in nearly all ponds and lagoons, with the highest relative abundance in sul2 at 6.3 × 10{sup −1} copies per 16S rRNA gene. A positive correlation was observed between total sul genes and total sulfonamides in water while the correlation was negative in sludge. No significant correlation was found between total tet genes and total tetracyclines in either water or sludge, but significant correlations were observed for certain individual tet genes. Ammonia concentrations strongly correlated with all ARGs except tetX. This study provided quantitative information on the occurrence of antimicrobials and ARGs in the liquid and solid compartments of typical manure treatment and storage structures. - Highlights: • Partitioning of antimicrobials between water and sludge is compound specific. • Antimicrobial resistance genes occurred in both water and sludge. • The ARG abundance varied more substantially in swine lagoons than in cattle ponds. • Correlations between ARGs and antimicrobials are system dependent.

  8. Narrow grass hedges reduce tylosin and associated antimicrobial resistance genes in agricultural runoff

    Science.gov (United States)

    Agricultural runoff from areas receiving livestock manure can potentially contaminate surface water with antimicrobials and antimicrobial resistance genes (ARGs). The objective of this study was to investigate the effectiveness of narrow grass hedges (NGHs) on reducing the transport of antimicrobial...

  9. [Insect antimicrobial peptides: structures, properties and gene regulation].

    Science.gov (United States)

    Wang, Yi-Peng; Lai, Ren

    2010-02-01

    Insect antimicrobial peptides (AMPs) are an important group of insect innate immunity effectors. Insect AMPs are cationic and contain less than 100 amino acid residues. According to structure, insect AMPs can be divided into a limited number of families. The diverse antimicrobial spectrum of insect AMPs may indicate different modes of action. Research on the model organism Drosophila indicate that insect AMPs gene regulation involves multiple signaling pathways and a large number of signaling molecules.

  10. Distribution of putative virulence genes and antimicrobial drug resistance in Vibrio harveyi

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Mendez, D.; Anto, C.

    environments for understanding the distribution of putative virulence genes and antimicrobial drug resistance. The putative genes targeted for PCR detection included four reversible toxin (Rtx)/hemolysin genes, a gene encoding homologue of Vibrio cholerae...

  11. Resistance of Antimicrobial Peptide Gene Transgenic Rice to Bacterial Blight

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; WU Chao; LIU Mei; LIU Xu-ri; Hu Guo-cheng; SI Hua-min; SUN Zong-xiu; LIU Wen-zhen; Fu Ya-ping

    2011-01-01

    Antimierobial peptide is a polypeptide with antimicrobial activity.Antimicrobial peptide genes Np3 and Np5 from Chinese shrimp (Fenneropenaeus Chinensis) were integrated into Oryza sativa L.subsp.japonica cv.Aichi ashahi by Agrobacterium mediated transformation system.PCR analysis showed that the positive ratios of Np3 and Np5 were 36% and 45% in T0 generation,respectively.RT-PCR analysis showed that the antimicrobial peptide genes were expressed in T1 generation,and there was no obvious difference in agronomic traits between transgenic plants and non-transgenic plants.Four Np3 and Np5 transgenic lines in T1 generation were inoculated with ×anthomonas oryzae pv.oryzae strain CR4,and all the four transgenic lines had significantly enhanced resistance to bacterial blight caused by the strain CR4.The Np5 transgenic lines also showed higher resistance to bacterial blight caused by strains JS97-2,Zhe 173 and OS-225.It is suggested that transgenic lines with Np5 gene might possess broad spectrum resistance to rice bacterial blight.

  12. Association between antimicrobial resistance and virulence genes in Escherichia coli obtained from blood and faeces

    DEFF Research Database (Denmark)

    Bagger-Skjøt, Line; Sandvang, Dorthe; Frimodt-Møller, Niels;

    2007-01-01

    Escherichia coli isolates obtained from faeces (n = 85) and blood (n = 123) were susceptibility tested against 17 antimicrobial agents and the presence of 9 virulence genes was determined by PCR. Positive associations between several antimicrobial resistances and 2 VF genes (iutA and traT) were...

  13. Antimicrobial resistance and antimicrobial resistance genes in marine bacteria from salmon aquaculture and non-aquaculture sites.

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    Shah, Syed Q A; Cabello, Felipe C; L'abée-Lund, Trine M; Tomova, Alexandra; Godfrey, Henry P; Buschmann, Alejandro H; Sørum, Henning

    2014-05-01

    Antimicrobial resistance (AR) detected by disc diffusion and antimicrobial resistance genes detected by DNA hybridization and polymerase chain reaction with amplicon sequencing were studied in 124 marine bacterial isolates from a Chilean salmon aquaculture site and 76 from a site without aquaculture 8 km distant. Resistance to one or more antimicrobials was present in 81% of the isolates regardless of site. Resistance to tetracycline was most commonly encoded by tetA and tetG; to trimethoprim, by dfrA1, dfrA5 and dfrA12; to sulfamethizole, by sul1 and sul2; to amoxicillin, by blaTEM ; and to streptomycin, by strA-strB. Integron integrase intl1 was detected in 14 sul1-positive isolates, associated with aad9 gene cassettes in two from the aquaculture site. intl2 Integrase was only detected in three dfrA1-positive isolates from the aquaculture site and was not associated with gene cassettes in any. Of nine isolates tested for conjugation, two from the aquaculture site transferred AR determinants to Escherichia coli. High levels of AR in marine sediments from aquaculture and non-aquaculture sites suggest that dispersion of the large amounts of antimicrobials used in Chilean salmon aquaculture has created selective pressure in areas of the marine environment far removed from the initial site of use of these agents.

  14. The pseudokinase NIPI-4 is a novel regulator of antimicrobial peptide gene expression.

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    Sid Ahmed Labed

    Full Text Available Hosts have developed diverse mechanisms to counter the pathogens they face in their natural environment. Throughout the plant and animal kingdoms, the up-regulation of antimicrobial peptides is a common response to infection. In C. elegans, infection with the natural pathogen Drechmeria coniospora leads to rapid induction of antimicrobial peptide gene expression in the epidermis. Through a large genetic screen we have isolated many new mutants that are incapable of upregulating the antimicrobial peptide nlp-29 in response to infection (i.e. with a Nipi or 'no induction of peptide after infection' phenotype. More than half of the newly isolated Nipi mutants do not correspond to genes previously associated with the regulation of antimicrobial peptides. One of these, nipi-4, encodes a member of a nematode-specific kinase family. NIPI-4 is predicted to be catalytically inactive, thus to be a pseudokinase. It acts in the epidermis downstream of the PKC∂ TPA-1, as a positive regulator of nlp antimicrobial peptide gene expression after infection. It also controls the constitutive expression of antimicrobial peptide genes of the cnc family that are targets of TGFß regulation. Our results open the way for a more detailed understanding of how host defense pathways can be molded by environmental pathogens.

  15. SCREENING OF ANTIMICROBIAL ACTIVITY AND GENES CODING POLYKETIDE SYNTHETASE AND NONRIBOSOMAL PEPTIDE SYNTHETASE OF ACTINOMYCETE ISOLATES

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    Silvia Kovácsová

    2013-12-01

    Full Text Available The aim of this study was to observe antimicrobial activity using agar plate diffusion method and screening genes coding polyketide synthetase (PKS-I and nonribosomal peptide synthetase (NRPS from actinomycetes. A total of 105 actinomycete strains were isolated from arable soil. Antimicrobial activity was demonstrated at 54 strains against at least 1 of total 12 indicator organisms. Antifungal properties were recorded more often than antibacterial properties. The presence of PKS-I and NRPS genes were founded at 61 of total 105 strains. The number of strains with mentioned biosynthetic enzyme gene fragments matching the anticipated length were 19 (18% and 50 (47% respectively. Overall, five actinomycete strains carried all the biosynthetical genes, yet no antimicrobial activity was found against any of tested pathogens. On the other hand, twenty-one strains showed antimicrobial activity even though we were not able to amplify any of the PKS or NRPS genes from them. Combination of the two methods showed broad-spectrum antimicrobial activity of actinomycetes isolated from arable soil, which indicate that actinomycetes are valuable reservoirs of novel bioactive compounds.

  16. Bacteriophages Isolated from Chicken Meat and the Horizontal Transfer of Antimicrobial Resistance Genes.

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    Shousha, Amira; Awaiwanont, Nattakarn; Sofka, Dmitrij; Smulders, Frans J M; Paulsen, Peter; Szostak, Michael P; Humphrey, Tom; Hilbert, Friederike

    2015-07-01

    Antimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments. The transfer of antimicrobial resistance genes by phages could underlie the origin of resistant bacteria found in food. We show that chicken meat carries a number of phages capable of transferring antimicrobial resistance. Of 243 phages randomly isolated from chicken meat, about a quarter (24.7%) were able to transduce resistance to one or more of the five antimicrobials tested into Escherichia coli ATCC 13706 (DSM 12242). Resistance to kanamycin was transduced the most often, followed by that to chloramphenicol, with four phages transducing tetracycline resistance and three transducing ampicillin resistance. Phages able to transduce antimicrobial resistance were isolated from 44% of the samples of chicken meat that we tested. The statistically significant (P = 0.01) relationship between the presence of phages transducing kanamycin resistance and E. coli isolates resistant to this antibiotic suggests that transduction may be an important mechanism for transferring kanamycin resistance to E. coli. It appears that the transduction of resistance to certain antimicrobials, e.g., kanamycin, not only is widely distributed in E. coli isolates found on meat but also could represent a major mechanism for resistance transfer. The result is of high importance for animal and human health.

  17. Bacteriophages Isolated from Chicken Meat and the Horizontal Transfer of Antimicrobial Resistance Genes

    Science.gov (United States)

    Shousha, Amira; Awaiwanont, Nattakarn; Sofka, Dmitrij; Smulders, Frans J. M.; Paulsen, Peter; Szostak, Michael P.; Humphrey, Tom

    2015-01-01

    Antimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments. The transfer of antimicrobial resistance genes by phages could underlie the origin of resistant bacteria found in food. We show that chicken meat carries a number of phages capable of transferring antimicrobial resistance. Of 243 phages randomly isolated from chicken meat, about a quarter (24.7%) were able to transduce resistance to one or more of the five antimicrobials tested into Escherichia coli ATCC 13706 (DSM 12242). Resistance to kanamycin was transduced the most often, followed by that to chloramphenicol, with four phages transducing tetracycline resistance and three transducing ampicillin resistance. Phages able to transduce antimicrobial resistance were isolated from 44% of the samples of chicken meat that we tested. The statistically significant (P = 0.01) relationship between the presence of phages transducing kanamycin resistance and E. coli isolates resistant to this antibiotic suggests that transduction may be an important mechanism for transferring kanamycin resistance to E. coli. It appears that the transduction of resistance to certain antimicrobials, e.g., kanamycin, not only is widely distributed in E. coli isolates found on meat but also could represent a major mechanism for resistance transfer. The result is of high importance for animal and human health. PMID:25934615

  18. Insights into novel antimicrobial compounds and antibiotic resistance genes from soil metagenomes

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    Alinne P Castro

    2014-09-01

    Full Text Available In recent years a major worldwide problem has arisen with regard to infectious diseases caused by resistant bacteria. Resistant pathogens are related to high mortality and also to enormous healthcare costs. In this field, cultured microorganisms have been commonly focused in attempts to isolate antibiotic resistance genes or to identify antimicrobial compounds. Although this strategy has been successful in many cases, most of the microbial diversity and related antimicrobial molecules have been completely lost. As an alternative, metagenomics has been used as a reliable approach to reveal the prospective reservoir of antimicrobial compounds and antibiotic resistance genes in the uncultured microbial community that inhabits a number of environments. In this context, this review will focus on resistance genes as well as on novel antibiotics revealed by a metagenomics approach from the soil environment. Biotechnology prospects are also discussed, opening new frontiers for antibiotic development.

  19. Virulence genes and antimicrobial susceptibility in Pasteurella multocida isolates from calves.

    Science.gov (United States)

    Katsuda, K; Hoshinoo, K; Ueno, Y; Kohmoto, M; Mikami, O

    2013-12-27

    A total of 378 isolates of Pasteurella multocida from clinically healthy and diseased calves were characterised for their susceptibility to 9 antimicrobial agents and screened by PCR for the presence of antimicrobial resistance genes and 22 genes virulence-associated, including capsule biosynthesis genes. Of the 378 isolates, 102 (27.0%) were resistant to at least one of the 9 tested antimicrobial agents. Resistance to oxytetracycline (21.7%) was the most frequently observed phenotype among the isolates. The tet(H) gene were the primary determinant detected. The resistance rates for thiamphenicol, ampicillin, kanamycin and florfenicol were 13.2%, 5.8%, 9.0% and 0.5%, respectively. Cefazolin, ceftiofur, cefquinome and enrofloxacin were effective antimicrobial agents, with no resistant isolates emerging over the course of the investigation. Most isolates were identified as capsular type A, only 6.3% belonged to capsular type D and no other capsular type was identified. Four of the virulence-associated genes (pfhA, tadD, tbpA and HAS) exhibited associations to the capsular type, and three (pfhA, tbpA and hgbB) were associated with the disease status of the animals. These virulence genes have been considered as epidemiological markers and are hypothesised to have a strong positive association with the outcome of disease in cattle.

  20. Cloning, expression, and purification of a new antimicrobial peptide gene from Musca domestica larva.

    Science.gov (United States)

    Pei, Zhihua; Sun, Xiaoning; Tang, Yan; Wang, Kai; Gao, Yunhang; Ma, Hongxia

    2014-10-01

    Musca domestica (Diptera: Muscidae), the housefly, exhibits unique immune defences and can produce antimicrobial peptides upon stimulation with bacteria. Based on the cDNA library constructed using the suppression subtractive hybridization (SSH) method, a 198-bp antimicrobial peptide gene, which we named MDAP-2, was amplified by rapid amplification of cDNA ends (RACE) from M. domestica larvae stimulated with Salmonella pullorum (Enterobacteriaceae: Salmonella). In the present study, the full-length MDAP-2 gene was cloned and inserted into a His-tagged Escherichia coli prokaryotic expression system to enable production of the recombinant peptide. The recombinant MDAP-2 peptide was purified using Ni-NTA HisTrap FF crude column chromatography. The bacteriostatic activity of the recombinant purified MDAP-2 protein was assessed. The results indicated that MDAP-2 had in vitro antibacterial activity against all of the tested Gram- bacteria from clinical isolates, including E. coli (Enterobacteriaceae: Escherichia), one strain of S. pullorum (Enterobacteriaceae: Salmonella), and one strain of Pasteurella multocida. DNA sequencing and BLAST analysis showed that the MDAP-2 antimicrobial peptide gene was not homologous to any other antimicrobial peptide genes in GenBank. The antibacterial mechanisms of the newly discovered MDAP-2 peptide warrant further study.

  1. Gene expression of oncogenes, antimicrobial peptides, and cytokines in the development of oral leukoplakia.

    NARCIS (Netherlands)

    Wenghoefer, M.; Pantelis, A.; Najafi, T.; Deschner, J.; Allam, J.P.; Novak, N.; Reich, R.; Martini, M.; Berge, S.J.; Fischer, H.P.; Jepsen, S.; Winter, J.

    2010-01-01

    OBJECTIVE: The aim of this study was to investigate the expression pattern of oncogenes, antimicrobial peptides, and genes involved in inflammation in leukoplakia of the oral cavity compared with healthy gingiva. STUDY DESIGN: Biopsies of healthy gingiva (n=20) and leukoplakia (n=20), were obtained

  2. Longitudinal characterization of antimicrobial resistance genes in feces shed from cattle fed different subtherapeutic antibiotics

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    Read Ronald R

    2011-01-01

    Full Text Available Abstract Background Environmental transmission of antimicrobial-resistant bacteria and resistance gene determinants originating from livestock is affected by their persistence in agricultural-related matrices. This study investigated the effects of administering subtherapeutic concentrations of antimicrobials to beef cattle on the abundance and persistence of resistance genes within the microbial community of fecal deposits. Cattle (three pens per treatment, 10 steers per pen were administered chlortetracycline, chlortetracycline plus sulfamethazine, tylosin, or no antimicrobials (control. Model fecal deposits (n = 3 were prepared by mixing fresh feces from each pen into a single composite sample. Real-time PCR was used to measure concentrations of tet, sul and erm resistance genes in DNA extracted from composites over 175 days of environmental exposure in the field. The microbial communities were analyzed by quantification and denaturing gradient gel electrophoresis (DGGE of PCR-amplified 16S-rRNA. Results The concentrations of 16S-rRNA in feces were similar across treatments and increased by day 56, declining thereafter. DGGE profiles of 16S-rRNA differed amongst treatments and with time, illustrating temporal shifts in microbial communities. All measured resistance gene determinants were quantifiable in feces after 175 days. Antimicrobial treatment differentially affected the abundance of certain resistance genes but generally not their persistence. In the first 56 days, concentrations of tet(B, tet(C, sul1, sul2, erm(A tended to increase, and decline thereafter, whereas tet(M and tet(W gradually declined over 175 days. At day 7, the concentration of erm(X was greatest in feces from cattle fed tylosin, compared to all other treatments. Conclusion The abundance of genes coding for antimicrobial resistance in bovine feces can be affected by inclusion of antibiotics in the feed. Resistance genes can persist in feces from cattle beyond 175 days

  3. Fate of antimicrobials and antimicrobial resistance genes in simulated swine manure storage

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    The behavior of three antibiotics (bacitracin, chlortetracycline, and tylosin) and two classes of antibiotic resistance genes (ARGs), tet and erm, were monitored in swine manure slurry under anaerobic conditions. First-order decay rates were determined for each antibiotic with half-lives ranging fr...

  4. Metagenomic Evidence of the Prevalence and Distribution Patterns of Antimicrobial Resistance Genes in Dairy Agroecosystems.

    Science.gov (United States)

    Pitta, Dipti W; Dou, Zhengxia; Kumar, Sanjay; Indugu, Nagaraju; Toth, John Daniel; Vecchiarelli, Bonnie; Bhukya, Bhima

    2016-06-01

    Antimicrobial resistance (AR) is a global problem with serious implications for public health. AR genes are frequently detected on animal farms, but little is known about their origin and distribution patterns. We hypothesized that AR genes can transfer from animal feces to the environment through manure, and to this end, we characterized and compared the resistomes (collections of AR genes) of animal feces, manure, and soil samples collected from five dairy farms using a metagenomics approach. Resistomes constituted only up to 1% of the total gene content, but were variable by sector and also farm. Broadly, the identified AR genes were associated with 18 antibiotic resistances classes across all samples; however, the most abundant genes were classified under multidrug transporters (44.75%), followed by resistance to vancomycin (12.48%), tetracycline (10.52%), bacitracin (10.43%), beta-lactam resistance (7.12%), and MLS efflux pump (6.86%) antimicrobials. The AR gene profiles were variable between farms. Farm 09 was categorized as a high risk farm, as a greater proportion of AR genes were common to at least three sectors, suggesting possible horizontal transfer of AR genes. Taxonomic characterization of AR genes revealed that a majority of AR genes were associated with the phylum Proteobacteria. Nonetheless, there were several members of Bacteroidetes, particularly Bacteroides genus and several lineages from Firmicutes that carried similar AR genes in different sectors, suggesting a strong potential for horizontal transfer of AR genes between unrelated bacterial hosts in different sectors of the farms. Further studies are required to affirm the horizontal gene transfer mechanisms between microbiomes of different sectors in animal agroecosystems.

  5. Comparative metagenomics reveals a diverse range of antimicrobial resistance genes in effluents entering a river catchment.

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    Rowe, Will; Verner-Jeffreys, David W; Baker-Austin, Craig; Ryan, Jim J; Maskell, Duncan J; Pearce, Gareth P

    2016-01-01

    The aquatic environment has been implicated as a reservoir for antimicrobial resistance genes (ARGs). In order to identify sources that are contributing to these gene reservoirs, it is crucial to assess effluents that are entering the aquatic environment. Here we describe a metagenomic assessment for two types of effluent entering a river catchment. We investigated the diversity and abundance of resistance genes, mobile genetic elements (MGEs) and pathogenic bacteria. Findings were normalised to a background sample of river source water. Our results show that effluent contributed an array of genes to the river catchment, the most abundant being tetracycline resistance genes tetC and tetW from farm effluents and the sulfonamide resistance gene sul2 from wastewater treatment plant (WWTP) effluents. In nine separate samples taken across 3 years, we found 53 different genes conferring resistance to seven classes of antimicrobial. Compared to the background sample taken up river from effluent entry, the average abundance of genes was three times greater in the farm effluent and two times greater in the WWTP effluent. We conclude that effluents disperse ARGs, MGEs and pathogenic bacteria within a river catchment, thereby contributing to environmental reservoirs of ARGs.

  6. Toxigenic genes, spoilage potential, and antimicrobial resistance of Bacillus cereus group strains from ice cream.

    Science.gov (United States)

    Arslan, Seza; Eyi, Ayla; Küçüksarı, Rümeysa

    2014-02-01

    Bacillus spp. can be recovered from almost every environment. It is also found readily in foods, where it may cause food spoilage and/or food poisoning due to its toxigenic and pathogenic nature, and extracellular enzymes. In this study, 29 Bacillus cereus group strains from ice cream were examined for the presence of following virulence genes hblC, nheA, cytK and ces genes, and tested for a range of the extracellular enzymes, and antimicrobial susceptibility. The strains were found to produce extracellular enzymes: proteolytic and lipolytic activity, gelatin hydrolysis and lecithinase production (100%), DNase production (93.1%) and amylase activity (93.1%). Of 29 strains examined, 24 (82.8%) showed hemolytic activity on blood agar. Beta-lactamase enzyme was only produced by 20.7% of B. cereus group. Among 29 B. cereus group from ice cream, nheA was the most common virulence gene detected in 44.8% of the strains, followed by hblC gene with 17.2%. Four (13.8%) of the 29 strains were positive for both hblC gene and nheA gene. Contrarily, cytK and ces genes were not detected in any of the strains. Antimicrobial susceptibility of ice cream isolates was tested to 14 different antimicrobial agents using the disc diffusion method. We detected resistance to penicillin and ampicillin with the same rate of 89.7%. Thirty-one percent of the strains were multiresistant to three or more antibiotics. This study emphasizes that the presence of natural isolates of Bacillus spp. harboring one or more enterotoxin genes, producing extracellular enzymes which may cause spoilage and acquiring antibiotic resistance might hold crucial importance in the food safety and quality.

  7. Antimicrobial susceptibility and distribution of antimicrobial-resistance genes among Enterococcus and coagulase-negative Staphylococcus isolates recovered from poultry litter.

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    Simjee, Shabbir; McDermott, Patrick F; White, David G; Hofacre, Charles; Berghaus, Roy D; Carter, Peggy J; Stewart, Leigh; Liu, Tongrui; Maier, Marie; Maurer, John J

    2007-12-01

    Data on the prevalence of antimicrobial resistant enterococci and staphylococci from the poultry production environment are sparse in the United States. This information is needed for science-based risk assessments of antimicrobial use in animal husbandry and potential public-health consequences. In this study, we assessed the susceptibility of staphylococci and enterococci isolated from poultry litter, recovered from 24 farms across Georgia, to several antimicrobials of veterinary and human health importance. Among the 90 Enterococcus isolates recovered, E. hirae (46%) was the most frequently encountered species, followed by E. faecium (27%), E. gallinarum (12%), and E. faecalis (10%). Antimicrobial resistance was most often observed to tetracycline (96%), followed by clindamycin (90%), quinupristin-dalfopristin (62%), penicillin (53%), erythromycin (50%), nitrofurantoin (49%), and clarithromycin (48%). Among the 110 staphylococci isolates recovered, only coagulase-negative staphylococci (CNS) were identified with the predominant Staphylococcus species being S. sciuri (38%), S. lentus (21%), S. xylosus (14%) and S. simulans (12%). Resistance was less-frequently observed among the Staphylococcus isolates for the majority of antimicrobials tested, as compared with Enterococcus isolates, and was primarily limited to clarithromycin (71%), erythromycin (71%), clindamycin (48%), and tetracycline (38%). Multidrug resistance (MDR) phenotypes were prevalent in both Enterococcus and Staphylococcus; however, Enterococcus exhibited a statistically significant difference in the median number of antimicrobials to which resistance was observed (median = 5.0) compared with Staphylococcus species (median = 3.0). Because resistance to several of these antimicrobials in gram-positive bacteria may be attributed to the shuttling of common drug-resistance genes, we also determined which common antimicrobial-resistance genes were present in both enterococci and staphylococci. The

  8. The dlt genes play a role in antimicrobial tolerance of Streptococcus mutans biofilms.

    Science.gov (United States)

    Nilsson, Martin; Rybtke, Morten; Givskov, Michael; Høiby, Niels; Twetman, Svante; Tolker-Nielsen, Tim

    2016-09-01

    Microbial biofilms are tolerant to antibiotic treatment and therefore cause problematic infections. Knowledge about the molecular mechanisms underlying biofilm-associated antimicrobial tolerance will aid the development of antibiofilm drugs. Screening of a Streptococcus mutans transposon mutant library for genes that are important for biofilm-associated antimicrobial tolerance provided evidence that the dlt genes play a role in the tolerance of S. mutans biofilms towards gentamicin. The minimum bactericidal concentration for biofilm cells (MBC-B) for a dltA transposon mutant was eight-fold lower than that of the wild-type. The minimum bactericidal concentration for planktonic cells (MBC-P) was only slightly reduced, indicating that the mechanism involved in the observed antimicrobial tolerance has a predominant role specifically in biofilms. Experiments with a knockout dltA mutant and complemented strain confirmed that the dlt genes in S. mutans play a role in biofilm-associated tolerance to gentamicin. Confocal laser scanning microscopy analyses of biofilms grown on glass slides showed that the dltA mutant produced roughly the same amount of biofilm as the wild-type, indicating that the reduced antimicrobial tolerance of the dltA mutant is not due to a defect in biofilm formation. The products of the dlt genes have been shown to mediate alanylation of teichoic acids, and in accordance the dltA mutant showed a more negatively charged surface than the wild-type, which likely is an important factor in the reduced tolerance of the dltA mutant biofilms towards the positively charged gentamicin.

  9. Haemophilus ducreyi Is Resistant to Human Antimicrobial Peptides▿

    OpenAIRE

    Mount, Kristy L. B.; Townsend, Carisa A.; Bauer, Margaret E.

    2007-01-01

    We examined the susceptibility of Haemophilus ducreyi to antimicrobial peptides likely to be encountered in vivo during human infection. H. ducreyi was significantly more resistant than Escherichia coli to the bactericidal effects of all peptides tested. Class I and II H. ducreyi strains exhibited similar levels of resistance to antimicrobial peptides.

  10. Haemophilus ducreyi is resistant to human antimicrobial peptides.

    Science.gov (United States)

    Mount, Kristy L B; Townsend, Carisa A; Bauer, Margaret E

    2007-09-01

    We examined the susceptibility of Haemophilus ducreyi to antimicrobial peptides likely to be encountered in vivo during human infection. H. ducreyi was significantly more resistant than Escherichia coli to the bactericidal effects of all peptides tested. Class I and II H. ducreyi strains exhibited similar levels of resistance to antimicrobial peptides.

  11. Screening, Expression, Purification and Functional Characterization of Novel Antimicrobial Peptide Genes from Hermetia illucens (L.)

    Science.gov (United States)

    Elhag, Osama; Zhou, Dingzhong; Song, Qi; Soomro, Abdul Aziz; Cai, Minmin; Zheng, Longyu; Yu, Ziniu; Zhang, Jibin

    2017-01-01

    Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against microbial-related diseases. In this study, seven new gene fragments of three types of antimicrobial peptides were obtained from Hermetia illucens (L), and were named cecropinZ1, sarcotoxin1, sarcotoxin (2a), sarcotoxin (2b), sarcotoxin3, stomoxynZH1, and stomoxynZH1(a). Among these genes, a 189-basepair gene (stomoxynZH1) was cloned into the pET32a expression vector and expressed in the Escherichia coli as a fusion protein with thioredoxin. Results show that Trx-stomoxynZH1 exhibits diverse inhibitory activity on various pathogens, including Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli, fungus Rhizoctonia solani Khün (rice)-10, and fungus Sclerotinia sclerotiorum (Lib.) de Bary-14. The minimum inhibitory concentration of Trx-stomoxynZH1 is higher against Gram-positive bacteria than against Gram-negative bacteria but similar between the fungal strains. These results indicate that H. illucens (L.) could provide a rich source for the discovery of novel antimicrobial peptides. Importantly, stomoxynZH1 displays a potential benefit in controlling antibiotic-resistant pathogens. PMID:28056070

  12. Characterization of Antimicrobial Resistance Patterns and Detection of Virulence Genes in Campylobacter Isolates in Italy

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    Elisabetta Di Giannatale

    2014-02-01

    Full Text Available Campylobacter has developed resistance to several antimicrobial agents over the years, including macrolides, quinolones and fluoroquinolones, becoming a significant public health hazard. A total of 145 strains derived from raw milk, chicken faeces, chicken carcasses, cattle faeces and human faeces collected from various Italian regions, were screened for antimicrobial susceptibility, molecular characterization (SmaI pulsed-field gel electrophoresis and detection of virulence genes (sequencing and DNA microarray analysis. The prevalence of C. jejuni and C. coli was 62.75% and 37.24% respectively. Antimicrobial susceptibility revealed a high level of resistance for ciprofloxacin (62.76%, tetracycline (55.86% and nalidixic acid (55.17%. Genotyping of Campylobacter isolates using PFGE revealed a total of 86 unique SmaI patterns. Virulence gene profiles were determined using a new microbial diagnostic microarray composed of 70-mer oligonucleotide probes targeting genes implicated in Campylobacter pathogenicity. Correspondence between PFGE and microarray clusters was observed. Comparisons of PFGE and virulence profiles reflected the high genetic diversity of the strains examined, leading us to speculate different degrees of pathogenicity inside Campylobacter populations.

  13. Virulence genes and antimicrobial resistance of Pasteurella multocida isolated from poultry and swine

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    Thales Quedi Furian

    2016-03-01

    Full Text Available Abstract Pasteurella multocida causes atrophic rhinitis in swine and fowl cholera in birds, and is a secondary agent in respiratory syndromes. Pathogenesis and virulence factors involved are still poorly understood. The aim of this study was to detect 22 virulence-associated genes by PCR, including capsular serogroups A, B and D genes and to evaluate the antimicrobial susceptibility of P. multocida strains from poultry and swine. ompH, oma87, plpB, psl, exbD-tonB, fur, hgbA, nanB, sodA, sodC, ptfA were detected in more than 90% of the strains of both hosts. 91% and 92% of avian and swine strains, respectively, were classified in serogroup A. toxA and hsf-1 showed a significant association to serogroup D; pmHAS and pfhA to serogroup A. Gentamicin and amoxicillin were the most effective drugs with susceptibility higher than 97%; however, 76.79% of poultry strains and 85% of swine strains were resistant to sulphonamides. Furthermore, 19.64% and 36.58% of avian and swine strains, respectively, were multi-resistant. Virulence genes studied were not specific to a host and may be the result of horizontal transmission throughout evolution. High multidrug resistance demonstrates the need for responsible use of antimicrobials in animals intended for human consumption, in addition to antimicrobial susceptibility testing to P. multocida.

  14. Trends in antimicrobial susceptibility in relation to antimicrobial usage and presence of resistance genes in Staphylococcus hyicus isolated from exudative epidermitis in pigs

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Jensen, Lars Bogø

    2002-01-01

    From 1996 to 2001 a total of 467 Staphylococcus hyicus isolates from exudative epidermitis (EE) in pigs in Denmark were examined for susceptibility to 13 different antimicrobial agents. The presence of selected genes encoding macrolide (erm(A), erm(B) and erm(C)), penicillin (blaZ), streptogramin...

  15. Molecular typing, pathogenicity factor genes and antimicrobial susceptibility of vancomycin resistant enterococci in Belgrade, Serbia.

    Science.gov (United States)

    Jovanović, Milica; Milošević, Branko; Tošić, Tanja; Stevanović, Goran; Mioljević, Vesna; Inđić, Nikola; Velebit, Branko; Zervos, Marcus

    2015-06-01

    In this study the distribution of species and antimicrobial resistance among vancomycin resistant enterococci (VRE) recovered from clinical specimens obtained from five hospitals in Belgrade was analyzed. Strains were further characterized by pulsed-field gel electrophoresis (PFGE). Polymerase chain reaction (PCR) was used to investigate the presence of vanA and vanB genes and pathogenicity factor genes. Identification of 194 VRE isolates revealed 154 Enterococcus faecium, 21 Enterococcus faecalis, 10 Enterococcus raffinosus and 9 Enterococcus gallinarum. This study revealed existence of 8 major clones of VRE. PCR determined vanA gene to be present in all of the VRE studied. Esp and hyl genes were present in 29.22% and 27.92% of E. faecium, respectively, and in 76.19% and 0 of E. faecalis, respectively. Esp and hyl genes were not found more frequently in members of predominant clones of E. faecium than in single isolates; nor was their presence connected to invasiveness.

  16. Rapid evolution of antimicrobial peptide genes in an insect host-social parasite system.

    Science.gov (United States)

    Erler, Silvio; Lhomme, Patrick; Rasmont, Pierre; Lattorff, H Michael G

    2014-04-01

    Selection, as a major driver for evolution in host-parasite interactions, may act on two levels; the virulence of the pathogen, and the hosts' defence system. Effectors of the host defence system might evolve faster than other genes e.g. those involved in adaptation to changes in life history or environmental fluctuations. Host-parasite interactions at the level of hosts and their specific social parasites, present a special setting for evolutionarily driven selection, as both share the same environmental conditions and pathogen pressures. Here, we study the evolution of antimicrobial peptide (AMP) genes, in six host bumblebee and their socially parasitic cuckoo bumblebee species. The selected AMP genes evolved much faster than non-immune genes, but only defensin-1 showed significant differences between host and social parasite. Nucleotide diversity and codon-by-codon analyses confirmed that purifying selection is the main selective force acting on bumblebee defence genes.

  17. Antimicrobial Susceptibility of Bordetella bronchiseptica Isolates from Swine and Companion Animals and Detection of Resistance Genes.

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    Sandra Prüller

    Full Text Available Bordetella bronchiseptica causes infections of the respiratory tract in swine and other mammals and is a precursor for secondary infections with Pasteurella multocida. Treatment of B. bronchiseptica infections is conducted primarily with antimicrobial agents. Therefore it is essential to get an overview of the susceptibility status of these bacteria. The aim of this study was to comparatively analyse broth microdilution susceptibility testing according to CLSI recommendations with an incubation time of 16 to 20 hours and a longer incubation time of 24 hours, as recently proposed to obtain more homogenous MICs. Susceptibility testing against a panel of 22 antimicrobial agents and two fixed combinations was performed with 107 porcine isolates from different farms and regions in Germany and 43 isolates obtained from companion animals in Germany and other European countries. Isolates with increased MICs were investigated by PCR assays for the presence of resistance genes. For ampicillin, all 107 porcine isolates were classified as resistant, whereas only a single isolate was resistant to florfenicol. All isolates obtained from companion animals showed elevated MICs for β-lactam antibiotics and demonstrated an overall low susceptibility to cephalosporines. Extension of the incubation time resulted in 1-2 dilution steps higher MIC50 values of porcine isolates for seven antimicrobial agents tested, while isolates from companion animals exhibited twofold higher MIC50/90 values only for tetracycline and cefotaxime. For three antimicrobial agents, lower MIC50 and MIC90 values were detected for both, porcine and companion animal isolates. Among the 150 isolates tested, the resistance genes blaBOR-1 (n = 147, blaOXA-2, (n = 4, strA and strB (n = 17, sul1 (n = 10, sul2 (n = 73, dfrA7 (n = 3 and tet(A (n = 8 were detected and a plasmid localisation was identified for several of the resistance genes.

  18. Curcumin induces human cathelicidin antimicrobial peptide gene expression through a vitamin D receptor-independent pathway

    DEFF Research Database (Denmark)

    Guo, Chunxiao; Rosoha, Elena; Lowry, Malcolm B;

    2013-01-01

    and PUFAs would induce expression of known VDR target genes in cells. In this study, we tested whether these compounds regulated two important VDR target genes - human cathelicidin antimicrobial peptide (CAMP) and 1,25-dihydroxyvitamin D(3) 24-hydroxylase (CYP24A1) - in human monocytic cell line U937, colon...... cancer cell line HT-29 and keratinocyte cell line HaCaT. We demonstrated that PUFAs failed to induce CAMP or CYP24A1 mRNA expression in all three cell lines, but curcumin up-regulated CAMP mRNA and protein levels in U937 cells. Curcumin treatment induced CAMP promoter activity from a luciferase reporter...

  19. Antimicrobial resistance, virulence genes, and genetic lineages of Staphylococcus pseudintermedius in healthy dogs in tunisia.

    Science.gov (United States)

    Gharsa, Haythem; Ben Slama, Karim; Gómez-Sanz, Elena; Lozano, Carmen; Klibi, Naouel; Jouini, Ahlem; Messadi, Lilia; Boudabous, Abdellatif; Torres, Carmen

    2013-08-01

    Nasal swabs of 100 healthy dogs were obtained in 2011 in Tunisia and tested for Staphylococcus pseudintermedius recovery. Antimicrobial resistance profile and virulence gene content were determined. Multilocus-sequence-typing (MLST) and SmaI-pulsed-field gel electrophoresis (PFGE) were investigated. S. pseudintermedius was recovered in 55 of the 100 tested samples (55 %), and one isolate per sample was further studied. All 55 S. pseudintermedius isolates were susceptible to methicillin (MSSP) but showed resistance to the following antimicrobials (% resistant isolates/resistance gene): penicillin (56.4/blaZ), tetracycline (40/tetM), trimethoprim-sulfamethoxazole (23.7), fusidic acid (9), kanamycin (3.7/aph(3´)-Ia), erythromycin-clindamycin (1.8/erm(B)), streptomycin (1.8/ant(6)-Ia), chloramphenicol (1.8) and ciprofloxacin (1.8). The following toxin genes were identified (% of isolates): lukS/F-I (98.2), expA (5.5), se-int (98.2), sec canine (1.8), siet (100), sea (5.5), seb (3.6), sec (10.9), sed (54.5), sei (5.5), sej (29.1), sek (3.6), ser (9.1), and hlg v (38.2). Ten different sequence-types were detected among 11 representative MSSP isolates: ST20, ST44, ST69, ST70, ST78, ST100, ST108, ST160, ST161, and ST162, the last three ones revealing novel alleles or allele combinations. Eleven different PFGE-patterns were identified in these isolates. The nares of healthy dogs could be a reservoir of antimicrobial resistant and virulent MSSP, highlighting the presence of the recently described exfoliating gene expA and several enterotoxin genes.

  20. Bacillus cereus from blood cultures: virulence genes, antimicrobial susceptibility and risk factors for blood stream infection.

    Science.gov (United States)

    Horii, Toshinobu; Notake, Shigeyuki; Tamai, Kiyoko; Yanagisawa, Hideji

    2011-11-01

    We characterized the profiles of virulence genes and antimicrobial susceptibility of Bacillus cereus isolates from blood cultures as well as the risk factors for blood stream infections (BSIs). The diversity of virulence gene patterns was found to be wide among 15 B. cereus isolates from BSIs and also among 11 isolates from contaminated blood cultures. The MicroScan broth microdilution method yielded results corresponding with those of the agar dilution (reference) method for levofloxacin, linezolid, and vancomycin, while the Etest results were consistent with the reference results for clindamycin, gentamicin, imipenem, levofloxacin, and linezolid. Compared with the reference values, however, some isolates showed marked differences of the minimum inhibitory concentrations (MICs) for ampicillin and clindamycin when determined using the MicroScan method, or the MICs for ampicillin, meropenem, and vancomycin when determined using the Etest method. Significantly more patients were treated with antimicrobials for more than 3 days during the 3-month period before isolation in the BSI group. Prior antimicrobial therapy may be a risk factor for BSIs due to B. cereus.

  1. Biodiversity of genes encoding anti-microbial traits within plant associated microbes

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    Walaa Kamel Mousa

    2015-04-01

    Full Text Available The plant is an attractive versatile home for diverse associated microbes. A subset of these microbes produce a diversity of anti-microbial natural products including polyketides, non-ribosomal peptides, terpenoids, heterocylic nitrogenous compounds, volatile compounds, bacteriocins and lytic enzymes. In recent years, detailed molecular analysis has led to a better understanding of the underlying genetic mechanisms. New genomic and bioinformatic tools have permitted comparisons of orthologous genes between species, leading to predictions of the associated evolutionary mechanisms responsible for diversification at the genetic and corresponding biochemical levels. The purpose of this review is to describe the biodiversity of biosynthetic genes of plant-associated bacteria and fungi that encode selected examples of antimicrobial natural products. For each compound, the target pathogen and biochemical mode of action are described, in order to draw attention to the complexity of these phenomena. We review recent information of the underlying molecular diversity and draw lessons through comparative genomic analysis of the orthologous genes. We conclude by discussing emerging themes and gaps, discuss the metabolic pathways in the context of the phylogeny and ecology of their microbial hosts, and discuss potential evolutionary mechanisms that led to the diversification of biosynthetic gene clusters.

  2. Prevalence of enterotoxin genes and antimicrobial resistance of coagulase-positive staphylococci recovered from raw cow milk.

    Science.gov (United States)

    Rola, J G; Korpysa-Dzirba, W; Czubkowska, A; Osek, J

    2015-07-01

    Raw milk may be contaminated by enterotoxigenic coagulase-positive staphylococci (CPS). Several of these microorganisms show antimicrobial resistance, which poses a potential risk for consumers. The aim of this study was to determine the occurrence of enterotoxin genes and antimicrobial resistance of CPS isolated from cow milk. A total of 115 samples were analyzed for the presence of CPS according to the International Organization for Standardization standard (ISO 6888-2). The genes were identified using 2multiplex PCR assays. Resistance of the isolates to 10 antimicrobials was determined using the minimum inhibitory concentration method. Overall, 71 samples (62%) were contaminated with CPS and 69 isolates were further analyzed. Among them, 20 (29%) strains harbored the enterotoxin genes. The most commonly detected staphylococcal enterotoxin markers were sed, sej, and ser, whereas none of the analyzed isolates possessed the seb and see genes. Almost one-half of the tested strains (43%) were resistant to one or more antimicrobial agents. Resistance to penicillin was the most common, followed by sulfamethoxazole and chloramphenicol. On the other hand, all strains were susceptible to ciprofloxacin, erythromycin, gentamicin, cefoxitin, and streptomycin. None of the strains was positive for the mecA and mecC (methicillin-resistant Staphylococcus aureus) genes. These results indicate that enterotoxigenic and antimicrobial-resistant CPS strains are present in raw milk, which may be a potential risk for public health.

  3. Modulation of antimicrobial host defense peptide gene expression by free fatty acids.

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    Lakshmi T Sunkara

    Full Text Available Routine use of antibiotics at subtherapeutic levels in animal feed drives the emergence of antimicrobial resistance. Development of antibiotic-alternative approaches to disease control and prevention for food animals is imperatively needed. Previously, we showed that butyrate, a major species of short-chain fatty acids (SCFAs fermented from undigested fiber by intestinal microflora, is a potent inducer of endogenous antimicrobial host defense peptide (HDP genes in the chicken (PLoS One 2011, 6: e27225. In the present study, we further revealed that, in chicken HD11 macrophages and primary monocytes, induction of HDPs is largely in an inverse correlation with the aliphatic hydrocarbon chain length of free fatty acids, with SCFAs being the most potent, medium-chain fatty acids moderate and long-chain fatty acids marginal. Additionally, three SCFAs, namely acetate, propionate, and butyrate, exerted a strong synergy in augmenting HDP gene expression in chicken cells. Consistently, supplementation of chickens with a combination of three SCFAs in water resulted in a further reduction of Salmonella enteritidis in the cecum as compared to feeding of individual SCFAs. More importantly, free fatty acids enhanced HDP gene expression without triggering proinflammatory interleukin-1β production. Taken together, oral supplementation of SCFAs is capable of boosting host immunity and disease resistance, with potential for infectious disease control and prevention in animal agriculture without relying on antibiotics.

  4. Virulence Genes, Genetic Diversity, Antimicrobial Susceptibility and Phylogenetic Background of Escherichia coli Isolates

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    Abdi

    2015-08-01

    Full Text Available Background The epidemiology of Uropathogenic Escherichia coli (UPEC in urban and rural communities in Iran was never investigated prior to this study. Objectives The aims of this study were to detect the frequency of virulence genes and determine the antimicrobial susceptibility and phylogenetic background of Escherichia coli isolates collected from urban and rural communities. Materials and Methods A total of 100 E. coli isolates were collected from urine samples of patients with urinary tract infections (UTIs residing in two different locations, and confirmed by current biochemical tests. The phylogenetic groups were determined by the triplex-polymerase chain reaction (PCR method, and multiplex PCRs were used to detect eight Vf genes (fimH, iucD, irp2, hlyA, ompT, iha, iroN, and cnf1. The susceptibility profile of E. coli isolates was determined by the disk diffusion method. Results Ninety-five percent of UPEC showed at least one of the virulence genes, the most prevalent being fimH (95%, followed by irp2 (89%, iucD (69%, ompT (67%, iroN (29%, and iha (29%. The various combinations of detected genes were designated as virulence patterns. Phylogenetic groups, B2 (55% and D (22%, comprised the majority of isolated strains. Phenotypic tests showed that 92%, 74% and 71% of the isolates were resistant to ampicillin, ceftizoxime and cefixime, respectively. Conclusions These findings indicate that the UPEC isolates had eight virulence factors with high frequencies. Moreover, these results suggest a direct connection between virulence factors, gene diversity, phylogenetic background, and antimicrobial resistance in UPEC isolates.

  5. IL-10 inhibits while calcitriol reestablishes placental antimicrobial peptides gene expression.

    Science.gov (United States)

    Olmos-Ortiz, Andrea; Noyola-Martínez, Nancy; Barrera, David; Zaga-Clavellina, Verónica; Avila, Euclides; Halhali, Ali; Biruete, Benjamín; Larrea, Fernando; Díaz, Lorenza

    2015-04-01

    IL-10 and calcitriol help to achieve a successful pregnancy by suppressing active maternal immunity; however, these factors exert opposite effects upon microbial infections. In the skin and immune cells, IL-10 downregulates β-defensins while calcitriol induces cathelicidin gene expression in various tissues including placenta. Though, the regulation of human placental β-defensins by IL-10 and calcitriol has not been studied. Therefore, we explored the regulation of these antimicrobial peptides expression in cultured placental cells by calcitriol and IL-10 alone and combined. Real time PCR showed that calcitriol stimulated, while IL-10 inhibited, β-defensins and cathelicidin gene expression (Pantimicrobial peptides gene expression above control values, overriding IL-10 inhibitory effects. Calcitriol downregulated endogenous IL-10 secretion. Interestingly, calcitriol and TNF-α cooperatively enhanced β-defensins, while TNF-α reduced basal and calcitriol-stimulated cathelicidin gene expression. In summary, calcitriol and IL-10 exerted opposite effects on antimicrobial peptides expression in the human placenta, suggesting that unbalanced production of IL-10 and calcitriol could be deleterious to innate immune responses during gestation. Our results suggest that calcitriol enhancement of placental defenses involves two mechanisms: (1) downregulation of IL-10 secretion and (2) direct upregulation of β-defensins and cathelicidin gene expression. Considering that IL-10 and calcitriol differentially regulate the innate immune response in the placenta, in the case of an infection, calcitriol might restrict IL-10 permissive actions towards microbial invasion while restrains inflammation, allowing for pregnancy to continue in quiescence. These results strongly advice maternal vitamin D sufficiency during pregnancy.

  6. Antimicrobial Resistance to Ceftazidime and Ceftriaxone, and Detection of TEM Gene in Esherchia Coli

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    Jahani, S. (MSc

    2014-11-01

    Full Text Available Background and Objective: In the past, most strains of E. coli were susceptible to a wide range of antimicrobial agents, but this situation is now changed by indiscriminate use of antibiotics. Ceftriaxone and Ceftazidime are the most current antibiotics used for Enterobacteriaceae infections in hospitals. The aim of this study was to determine antimicrobial resistance of Escherichia coli strains isolated from patients. Material and Methods: During a 12-month period, 200 clinical samples taken from patients referred to Zahedan hospitals were assessed to isolate Escherichia coli. Antibiotic susceptibility was determined by disk diffusion method and micro-broth dilution; and Bla TEM resistance genes were detected by PCR. Results: Following phenotype verification testing, 112 isolates (56% were produced Extended Spectrum Beta Lactamase (ESBLs and 130 isolates were potential producers of beta-lactamase (ESBL. Using PCR, 72 isolates (38.55% have TEM gene. Conclusion: The rate of antibiotic resistance of Escherichia coli isolates to ceftriaxone and ceftazidime is high; therefore, it seems reasonable to do antibiogram before treatment.

  7. Prevalence, toxin gene profiles, and antimicrobial resistance of Staphylococcus aureus isolated from quick-frozen dumplings.

    Science.gov (United States)

    Hao, Dan; Xing, Xiaonan; Li, Guanghui; Wang, Xin; Zhang, Min; Zhang, Weisong; Xia, Xiaodong; Meng, Jianghong

    2015-01-01

    The aim of this study was to investigate the prevalence of Staphylococcus aureus in quick-frozen dumplings and to characterize these strains. A total of 120 dumpling samples, including lamb (n = 13), vegetarian (n = 14), seafood (n = 12), and pork (n = 81) stuffing, were collected in Shaanxi province in China and screened for S. aureus. All S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of genes encoding staphylococcal enterotoxins, exfoliative toxins A and B (eta and etb), toxic shock syndrome toxin 1 (tsst-1), and resistance to methicillin-oxacillin (mecA). In all, 60.0% of all samples were positive for S. aureus, and 117 S. aureus isolates, including seven mecA-positive strains, were recovered from these positive samples. In addition, all mecA-positive S. aureus isolates were recovered from products of animal origin. In these S. aureus isolates, resistance was observed most frequently to ampicillin (92.3%) and penicillin (86.3%), followed by clarithromycin, erythromycin, midecamycin, tetracycline, and kanahemycin (from 53.8 to 28.2%). All isolates were sensitive to cefoperazone, minocycline, vancomycin, and ofloxacin. The predominant toxin gene was sec (38.5%), followed by seg (19.7%), sej (16.2%), see (12.8%), sea (11.1%), and seb (10.3%), whereas eta, etb, and tsst-1 genes were not detected. These findings indicate that S. aureus was present commonly in quick-frozen dumplings, accompanied by multiple antimicrobial resistance and toxin genes. Our findings highlight the urgency for stricter hygiene strategies in food production and the prudent use of antibiotics in the breeding industry.

  8. Relationship between antimicrobial resistance and aminoglycoside-modifying enzyme gene expressions in Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    SHI Wei-feng; JIANG Jian-ping; MI Zu-huang

    2005-01-01

    Background Acinetobacter baumannii is one of the main gram-negative bacilli in clinical practice. Nosocomial infections caused by multi-drug resistance Acinetobacter baumannii is very difficult to treat. This study was designed to investigate the antimicrobial resistance characteristics and four resistant gene expressions of aminoglycoside-modifying enzymes including N-acetyltransferases and O-phosphotransferases in Acinetobacter baumannii. Methods Bacterial identification and antimicrobial susceptibility test were performed by PhoenixTM system in 247 strains of Acinetobacter baumannii. Minimal inhibitory concentrations (MICs) of seven aminoglycosides including gentamicin, amikacin, kanamycin, tobramycin, netilmicin, neomycin and streptomycin in 15 strains of multi-drug resistant Acinetobacter baumannii were detected by agar dilution. Four aminoglycoside-modifying enzyme genes were amplified by polymerase chain reaction (PCR) and verified by DNA sequencer.Results The resistance rates of 247 strains of Acinetobacter baumannii against cefotaxime, levofloxacin, piperacillin, aztreonam, tetracycline, ciprofloxacin and chloramphenicol were more than 50%. Imipenem and meropenem showed high antibacterial activities with resistance rates of 3.2% and 4.1%. MIC50 and MIC90 of gentamicin, amikacin, streptomycin and kanamycin in 15 strains of multi-drug resistant Acinetobacter baumanii were all more than 1024 mg/L, and the resistance rates were 100%, 100%, 100% and 93.3%, respectively. But their resistance rates to tobramycin, netilmicin and neomycin were 86.7%, 93.3% and 46.7%, respectively. Three modifying enzyme genes, including aacC1, aacC2 and aacA4 genes, were found in 15 strains, but aphA6 had not been detected. Their positive rates were 93.3%, 20.0% and 20.0%, respectively. These three genes existed simultaneously in No.19 strain. Nucleotide sequences of aacC1, aacC2 and aacA4 genes shared 100%, 97.9% and 99.7% identities with GenBank genes (AY307113, S68058 and AY

  9. Characterization of Toxin Genes and Antimicrobial Susceptibility of Staphylococcus aureus Isolates in Fishery Products in Iran

    Science.gov (United States)

    Arfatahery, Noushin; Davoodabadi, Abolfazl; Abedimohtasab, Taranehpeimaneh

    2016-01-01

    Staphylococcus aureus is one of the most common causes of seafood-borne diseases worldwide, which are attributable to the contamination of food by preformed enterotoxins. In this study, a total of 206 (34.3%) Staphylococcus aureus strains were obtained from 600 fish and shrimp samples and were tested for their antimicrobial susceptibility. We assessed the prevalence of the genes responsible for the staphylococcal enterotoxins (SEA, SEB) and toxic shock syndrome toxin 1 (TSST-1) genes. The results indicated that 34% of aqua food samples were contaminated with S. aureus, and 23.8% of these isolates were mec-A-positive. Sixty-four percent of the strains isolated from contaminated seafood was enterotoxigenic S. aureus, and 28.2% of SEs were MRSA-positive. The most prevalent genotype was characterized by the presence of the sea gene (45.2%), followed by the seb gene (18.5%), and the tst gene encoding TSST-1 was found in eight strains (3.9%). Of the 206 S. aureus isolates, 189 strains (84.9%) were resistant to at least one antibiotic. Given the frequent outbreaks of enterotoxigenic MRSA, it is necessary to make revisions to mandatory programmes to facilitate improved hygiene practices during fishing, aquaculture, processing, and sales to prevent the contamination of fishery products in Iran. PMID:27694813

  10. Development of a miniaturised microarray-based assay for the rapid identification of antimicrobial resistance genes in Gram-negative bacteria

    DEFF Research Database (Denmark)

    Batchelor, Miranda; Hopkins, Katie L; Liebana, Ernesto

    2008-01-01

    We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and beta-lactams, including extended-spectrum ......We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and beta-lactams, including extended...

  11. Lipopolysaccharide Biosynthesis Genes of Yersinia pseudotuberculosis Promote Resistance to Antimicrobial Chemokines

    Science.gov (United States)

    Erickson, David L.; Lew, Cynthia S.; Kartchner, Brittany; Porter, Nathan T.; McDaniel, S. Wade; Jones, Nathan M.; Mason, Sara; Wu, Erin; Wilson, Eric

    2016-01-01

    Antimicrobial chemokines (AMCs) are a recently described family of host defense peptides that play an important role in protecting a wide variety of organisms from bacterial infection. Very little is known about the bacterial targets of AMCs or factors that influence bacterial susceptibility to AMCs. In an effort to understand how bacterial pathogens resist killing by AMCs, we screened Yersinia pseudotuberculosis transposon mutants for those with increased binding to the AMCs CCL28 and CCL25. Mutants exhibiting increased binding to AMCs were subjected to AMC killing assays, which revealed their increased sensitivity to chemokine-mediated cell death. The majority of the mutants exhibiting increased binding to AMCs contained transposon insertions in genes related to lipopolysaccharide biosynthesis. A particularly strong effect on susceptibility to AMC mediated killing was observed by disruption of the hldD/waaF/waaC operon, necessary for ADP-L-glycero-D-manno-heptose synthesis and a complete lipopolysaccharide core oligosaccharide. Periodate oxidation of surface carbohydrates also enhanced AMC binding, whereas enzymatic removal of surface proteins significantly reduced binding. These results suggest that the structure of Y. pseudotuberculosis LPS greatly affects the antimicrobial activity of AMCs by shielding a protein ligand on the bacterial cell surface. PMID:27275606

  12. Molecular characterization of antimicrobial peptide genes of the carpenter ant Camponotus floridanus.

    Science.gov (United States)

    Ratzka, Carolin; Förster, Frank; Liang, Chunguang; Kupper, Maria; Dandekar, Thomas; Feldhaar, Heike; Gross, Roy

    2012-01-01

    The production of antimicrobial peptides (AMPs) is a major defense mechanism against pathogen infestation and of particular importance for insects relying exclusively on an innate immune system. Here, we report on the characterization of three AMPs from the carpenter ant Camponotus floridanus. Due to sequence similarities and amino acid composition these peptides can be classified into the cysteine-rich (e.g. defensin) and glycine-rich (e.g. hymenoptaecin) AMP groups, respectively. The gene and cDNA sequences of these AMPs were established and their expression was shown to be induced by microbial challenge. We characterized two different defensin genes. The defensin-2 gene has a single intron, whereas the defensin-1 gene has two introns. The deduced amino acid sequence of the C. floridanus defensins is very similar to other known ant defensins with the exception of a short C-terminal extension of defensin-1. The hymenoptaecin gene has a single intron and a very peculiar domain structure. The corresponding precursor protein consists of a signal- and a pro-sequence followed by a hymenoptaecin-like domain and six directly repeated hymenoptaecin domains. Each of the hymenoptaecin domains is flanked by an EAEP-spacer sequence and a RR-site known to be a proteolytic processing site. Thus, proteolytic processing of the multipeptide precursor may generate several mature AMPs leading to an amplification of the immune response. Bioinformatical analyses revealed the presence of hymenoptaecin genes with similar multipeptide precursor structure in genomes of other ant species suggesting an evolutionary conserved important role of this gene in ant immunity.

  13. Molecular characterization of antimicrobial peptide genes of the carpenter ant Camponotus floridanus.

    Directory of Open Access Journals (Sweden)

    Carolin Ratzka

    Full Text Available The production of antimicrobial peptides (AMPs is a major defense mechanism against pathogen infestation and of particular importance for insects relying exclusively on an innate immune system. Here, we report on the characterization of three AMPs from the carpenter ant Camponotus floridanus. Due to sequence similarities and amino acid composition these peptides can be classified into the cysteine-rich (e.g. defensin and glycine-rich (e.g. hymenoptaecin AMP groups, respectively. The gene and cDNA sequences of these AMPs were established and their expression was shown to be induced by microbial challenge. We characterized two different defensin genes. The defensin-2 gene has a single intron, whereas the defensin-1 gene has two introns. The deduced amino acid sequence of the C. floridanus defensins is very similar to other known ant defensins with the exception of a short C-terminal extension of defensin-1. The hymenoptaecin gene has a single intron and a very peculiar domain structure. The corresponding precursor protein consists of a signal- and a pro-sequence followed by a hymenoptaecin-like domain and six directly repeated hymenoptaecin domains. Each of the hymenoptaecin domains is flanked by an EAEP-spacer sequence and a RR-site known to be a proteolytic processing site. Thus, proteolytic processing of the multipeptide precursor may generate several mature AMPs leading to an amplification of the immune response. Bioinformatical analyses revealed the presence of hymenoptaecin genes with similar multipeptide precursor structure in genomes of other ant species suggesting an evolutionary conserved important role of this gene in ant immunity.

  14. Trends in antimicrobial susceptibility and presence of resistance genes in Staphylococcus hyicus isolated from exudative epidermitis in pigs

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Jensen, L. B.

    2002-01-01

    From 1996 to 2001 a total of 467 Staphylococcus hyicus isolates from exudative epidermitis (EE) in pigs in Denmark were examined for susceptibility to 13 different antimicrobial agents. The presence of selected genes encoding macrolide (erm(A), erm(B) and erm(C)), penicillin (blaZ), streptogramin...

  15. The signal peptide-like segment of hpaXm is required for its association to the cell wall in transgenic tobacco plants

    Science.gov (United States)

    Li, Le; Miao, Weiguo; Liu, Wenbo; Zhang, Shujian

    2017-01-01

    Harpins, encoded by hrp (hypersensitive response and pathogenicity) genes of Gram-negative plant pathogens, are elicitors of hypersensitive response (HR). HpaXm is a novel harpin-like protein described from cotton leaf blight bacteria, Xanthomonas citri subsp. malvacearum—a synonym of X. campestris pv. malvacearum (Smith 1901–1978). A putative signal peptide (1-MNSLNTQIGANSSFL-15) of hpaXm was predicted in the nitroxyl-terminal (N-terminal)by SignalP (SignalP 3.0 server). Here, we explored the function of the N-terminal leader peptide like segment of hpaXm using transgenic tobacco (Nicotiana tabacum cv. Xanthi nc.). Transgenic tobacco lines expressing the full-length hpaXm and the signal peptide-like segment-deleted mutant hpaXmΔLP were developed using transformation mediated by Agrobacterium tumefaciens. The target genes were confirmed integrated into the tobacco genomes and expressed normally. Using immune colloidal-gold detection technique, hpaXm protein was found to be transferred to the cytoplasm, the cell membrane, and organelles such as chloroplasts, mitochondria, and nucleus, as well as the cell wall. However, the deletion mutant hpaXmΔLP expressed in transgenic tobacco was found unable to cross the membrane to reach the cell wall. Additionally, soluble proteins extracted from plants transformed with hpaXm and hpaXmΔLP were bio-active. Defensive micro-HR induced by the transgene expression of hpaXm and hpaXmΔLP were observed on transgenic tobacco leaves. Disease resistance bioassays to tobacco mosaic virus (TMV) showed that tobacco plants transformed with hpaXm and with hpaXmΔLP exhibited enhanced resistance to TMV. In summary, the N-terminal signal peptide-like segment (1–45 bp) in hpaXm sequence is not necessary for transgene expression, bioactivity of hpaXm and resistance to TMV in transgenic tobacco, but is required for the protein to be translocated to the cell wall. PMID:28141855

  16. Iterative structure-based peptide-like inhibitor design against the botulinum neurotoxin serotype A.

    Directory of Open Access Journals (Sweden)

    Jorge E Zuniga

    Full Text Available The botulinum neurotoxin serotype A light chain (BoNT/A LC protease is the catalytic component responsible for the neuroparalysis that is characteristic of the disease state botulism. Three related peptide-like molecules (PLMs were designed using previous information from co-crystal structures, synthesized, and assayed for in vitro inhibition against BoNT/A LC. Our results indicate these PLMS are competitive inhibitors of the BoNT/A LC protease and their K(i values are in the nM-range. A co-crystal structure for one of these inhibitors was determined and reveals that the PLM, in accord with the goals of our design strategy, simultaneously involves both ionic interactions via its P1 residue and hydrophobic contacts by means of an aromatic group in the P2' position. The PLM adopts a helical conformation similar to previously determined co-crystal structures of PLMs, although there are also major differences to these other structures such as contacts with specific BoNT/A LC residues. Our structure further demonstrates the remarkable plasticity of the substrate binding cleft of the BoNT/A LC protease and provides a paradigm for iterative structure-based design and development of BoNT/A LC inhibitors.

  17. Frequency, virulence genes and antimicrobial resistance of Listeria spp. isolated from bovine clinical mastitis.

    Science.gov (United States)

    Jamali, Hossein; Radmehr, Behrad

    2013-11-01

    The aims of this study were to determine the prevalence, characteristics and antimicrobial resistance of Listeria spp. isolated from bovine clinical mastitis in Iran. Listeria spp. were detected in 21/207 bovine mastitic milk samples from dairy farms in Iran, comprising L. monocytogenes (n=17), L. innocua (n=3) and L. ivanovii (n=1). L. monocytogenes isolates were grouped into serogroups '4b, 4d, 4e', '1/2a, 3a', '1/2b, 3b, 7' and '1/2c, 3c'; all harboured inlA, inlC and inlJ virulence genes. Listeria spp. were most frequently resistant to penicillin G (14/21 isolates, 66.7%) and tetracyclines (11/21 isolates, 52.4%).

  18. Antimicrobial susceptibility, virulence genes, and randomly amplified polymorphic DNA analysis of Staphylococcus aureus recovered from bovine mastitis in Ningxia, China.

    Science.gov (United States)

    Wang, Dong; Zhang, Limei; Zhou, Xuezhang; He, Yulong; Yong, Changfu; Shen, Mingliang; Szenci, Otto; Han, Bo

    2016-12-01

    Staphylococcus aureusis the leading pathogen involved inbovine mastitis, but knowledgeabout antimicrobial resistance, virulence factors, and genotypes of Staphylococcus aureus resulting in bovine mastitis in Ningxia, China, is limited. Therefore, antimicrobial susceptibility, virulence gene, and randomly amplified polymorphic DNA (RAPD) analyses of Staph. aureus were carried out. A total of 327 milk samples from cows with clinical and subclinical mastitis in 4 regions of Ningxia were used for the isolation and identification of pathogens according to phenotypic and molecular characteristics. Antimicrobial susceptibility against 22 antimicrobial agents was determined by disk diffusion. The presence of 8 virulence genes in Staph. aureus isolates was tested by PCR. Genotypes of isolates were investigated based on RAPD. Results showed that 35 isolates obtained from mastitis milk samples were identified as Staph. aureus. The isolates were resistant to sulfamethoxazole (100%), penicillin G (94.3%), ampicillin (94.3%), erythromycin (68.6%), azithromycin (68.6%), clindamycin (25.7%), amoxicillin (11.4%), and tetracycline (5.7%). All of the isolates contained one or more virulence genes with average (standard deviation) of 6.6±1.6. The most prevalent virulence genes were hlb (97.1%), followed by fnbpA, hla, coa (94.3% each), nuc (85.7%), fnbpB (80%), clfA (77.1%), and tsst-1 (40%). Nine different gene patterns were found and 3 of them were the dominant gene combinations (77.1%). Staphylococcus aureus isolates (n=35) were divided into 6 genotypes by RAPD tying, the genotypes III and VI were the most prevalent genotypes. There was greatvariation in genotypes of Staph. aureus isolates, not only among different farms, but also within the same herd in Ningxia province. The study showed a high incidence of Staph. aureus with genomic variation of resistance genes, which is matter of great concern in public and animal health in Ningxia province of China.

  19. High prevalence of multidrug-tolerant bacteria and associated antimicrobial resistance genes isolated from ornamental fish and their carriage water.

    Directory of Open Access Journals (Sweden)

    David W Verner-Jeffreys

    Full Text Available BACKGROUND: Antimicrobials are used to directly control bacterial infections in pet (ornamental fish and are routinely added to the water these fish are shipped in to suppress the growth of potential pathogens during transport. METHODOLOGY/PRINCIPAL FINDINGS: To assess the potential effects of this sustained selection pressure, 127 Aeromonas spp. isolated from warm and cold water ornamental fish species were screened for tolerance to 34 antimicrobials. Representative isolates were also examined for the presence of 54 resistance genes by a combination of miniaturized microarray and conventional PCR. Forty-seven of 94 Aeromonas spp. isolates recovered from tropical ornamental fish and their carriage water were tolerant to > or =15 antibiotics, representing seven or more different classes of antimicrobial. The quinolone and fluoroquinolone resistance gene, qnrS2, was detected at high frequency (37% tested recent isolates were positive by PCR. Class 1 integrons, IncA/C broad host range plasmids and a range of other antibiotic resistance genes, including floR, bla(TEM-1, tet(A, tet(D, tet(E, qacE2, sul1, and a number of different dihydrofolate reductase and aminoglycoside transferase coding genes were also detected in carriage water samples and bacterial isolates. CONCLUSIONS: These data suggest that ornamental fish and their carriage water act as a reservoir for both multi-resistant bacteria and resistance genes.

  20. Prevalence of virulence and antimicrobial resistance genes in Salmonella spp. isolated from commercial chickens and human clinical isolates from South Africa and Brazil

    Directory of Open Access Journals (Sweden)

    Oliver T. Zishiri

    2016-03-01

    Full Text Available Salmonellosis is a significant public health concern around the world. The injudicious use of antimicrobial agents in poultry production for treatment, growth promotion and prophylaxis has resulted in the emergence of drug resistant strains of Salmonella. The current study was conducted to investigate the prevalence of virulence and antimicrobial resistance genes from Salmonella isolated from South African and Brazilian broiler chickens as well as human clinical isolates. Out of a total of 200 chicken samples that were collected from South Africa 102 (51% tested positive for Salmonella using the InvA gene. Of the overall 146 Salmonella positive samples that were screened for the iroB gene most of them were confirmed to be Salmonella enterica with the following prevalence rates: 85% of human clinical samples, 68.6% of South African chicken isolates and 70.8% of Brazilian chicken samples. All Salmonella isolates obtained were subjected to antimicrobial susceptibility testing with 10 antibiotics. Salmonella isolates from South African chickens exhibited resistance to almost all antimicrobial agents used, such as tetracycline (93%, trimethoprim-sulfamthoxazole (84%, trimethoprim (78.4%, kanamycin (74%, gentamicin (48%, ampicillin (47%, amoxicillin (31%, chloramphenicol (31%, erythromycin (18% and streptomycin (12%. All samples were further subjected to PCR in order to screen some common antimicrobial and virulence genes of interest namely spiC, pipD, misL, orfL, pse-1, tet A, tet B, ant (3"-la, sul 1 and sul. All Salmonella positive isolates exhibited resistance to at least one antimicrobial agent; however, antimicrobial resistance patterns demonstrated that multiple drug resistance was prevalent. The findings provide evidence that broiler chickens are colonised by pathogenic Salmonella harbouring antimicrobial resistance genes. Therefore, it is evident that there is a need for prudent use of antimicrobial agents in poultry production systems in

  1. The effect of peptidoglycan enriched diets on antimicrobial peptide gene expression in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Casadei, Elisa; Bird, Steve; Vecino, Jose L González; Wadsworth, Simon; Secombes, Christopher J

    2013-02-01

    The aim of this study was to investigate the effect of feeding rainbow trout (Oncorhynchus mykiss) peptidoglycan (PG) enriched diets on antimicrobial peptide (AMP) gene expression. Fish were divided into 5 groups and fed diets containing 0, 5, 10, 50 and 100 mg PG/Kg, and sampled 1, 7 and 14 days later. The expression of eight AMP genes (four defensins, two cathelicidins and two liver expressed AMPs) was determined in skin, gill, gut and liver, tissues important for first lines of defence or production of acute phase proteins. Up-regulation of many AMPs was found after feeding the PG enriched diets, with sequential expression seen over the time course studied, where defensins were typically expressed early and cathelicidins and LEAPs later on. A number of clear differences in AMP responsiveness between the tissues examined were also apparent. Of the four PG concentrations used, 5 mg PG/Kg did not always elicit AMP gene induction or to the same degree as seen with the other diets. The three higher dose groups generally showed similar trends although differences in fold change were more pronounced in the 50 and 100 mg PG/Kg groups. Curiously several AMPs were down-regulated after 14 days of feeding in gills, gut and liver. Nevertheless, overall the PG enriched diets had a positive effect on AMP expression. Further investigations now need to be undertaken to confirm whether this higher AMP gene expression correlates with protection against common bacterial diseases and if PG enriched diets have value as a means to temporarily boost the piscine immune system.

  2. Comparison of adhesin genes and antimicrobial susceptibilities between uropathogenic and intestinal commensal Escherichia coli strains.

    Science.gov (United States)

    Qin, Xiaohua; Hu, Fupin; Wu, Shi; Ye, Xinyu; Zhu, Demei; Zhang, Ying; Wang, Minggui

    2013-01-01

    The presence of adhesins is arguably an important determinant of pathogenicity for Uropathogenic Escherichia coli (UPEC). Antimicrobial susceptibilities were tested by agar dilution method, fifteen adhesin genes were detected by polymerase chain reaction, and multilocus sequence typing (MLST) was analyzed in 70 UPEC isolates and 41 commensal E. coli strains. Extended-spectrum β-lactamase (ESBL) was determined with confirmatory test. The prevalence of ESBL-producers in UPEC (53%, 37/70) was higher than the commensal intestinal isolates (7%, 3/41), and 97% (36/37) of the ESBL-producing UPEC harbored bla CTX-M genes. afa was present in 36% (10/28) UPEC isolates from recurrent lower urinary tract infection (UTI), and none in the acute pyelonephritis, acute uncomplicated cystitis or commensal strains (PUPEC isolates, while 5% (2/41) of the commensal strains were papG positive (P = 0.0025), and the prevalence of papG was significantly higher in acute pyelonephritis group (71%) than the other two UTI groups (PUPEC isolates than in the commensal strains. ESBL-producing UPEC showed a lower prevalence of adhesin genes compared with non-ESBL-producing strains. The MLST profiles were different between UPEC and commensal strains, with ST131 (19%, 13/70) and ST10 (20%, 8/41) being the most common MLSTs, respectively. This study demonstrated that several adhesin genes were more prevalent in UPEC isolates than in commensal E. coli, and afa may be associated with recurrent lower UTI whereas papG is more frequently associated with acute pyelonephritis.

  3. An alpha-helical cationic antimicrobial peptide selectively modulates macrophage responses to lipopolysaccharide and directly alters macrophage gene expression.

    Science.gov (United States)

    Scott, M G; Rosenberger, C M; Gold, M R; Finlay, B B; Hancock, R E

    2000-09-15

    Certain cationic antimicrobial peptides block the binding of LPS to LPS-binding protein and reduce the ability of LPS to induce the production of inflammatory mediators by macrophages. To gain a more complete understanding of how LPS activates macrophages and how cationic peptides influence this process, we have used gene array technology to profile gene expression patterns in macrophages treated with LPS in the presence or the absence of the insect-derived cationic antimicrobial peptide CEMA (cecropin-melittin hybrid). We found that CEMA selectively blocked LPS-induced gene expression in the RAW 264.7 macrophage cell line. The ability of LPS to induce the expression of >40 genes was strongly inhibited by CEMA, while LPS-induced expression of another 16 genes was relatively unaffected. In addition, CEMA itself induced the expression of a distinct set of 35 genes, including genes involved in cell adhesion and apoptosis. Thus, CEMA, a synthetic alpha-helical peptide, selectively modulates the transcriptional response of macrophages to LPS and can alter gene expression in macrophages.

  4. Incidence, Antimicrobial Susceptibility, and Toxin Genes Possession Screening of Staphylococcus aureus in Retail Chicken Livers and Gizzards

    Directory of Open Access Journals (Sweden)

    Lubna S. Abdalrahman

    2015-04-01

    Full Text Available Few recent outbreaks in Europe and the US involving Campylobacter and Salmonella were linked to the consumption of chicken livers. Studies investigating Staphylococcus aureus in chicken livers and gizzards are very limited. The objectives of this study were to determine the prevalence, antimicrobial resistance, and virulence of S. aureus and MRSA (Methicillin-Resistant Staphylococcus aureus in retail chicken livers and gizzards in Tulsa, Oklahoma. In this study, 156 chicken livers and 39 chicken gizzards samples of two brands were collected. While one of the brands showed very low prevalence of 1% (1/100 for S. aureus in chicken livers and gizzards, the second brand showed prevalence of 37% (31/95. No MRSA was detected since none harbored the mecA or mecC gene. Eighty seven S. aureus isolates from livers and 28 from gizzards were screened for antimicrobial resistance to 16 antimicrobials and the possession of 18 toxin genes. Resistance to most of the antimicrobials screened including cefoxitin and oxacillin was higher in the chicken gizzards isolates. While the prevalence of enterotoxin genes seg and sei was higher in the gizzards isolates, the prevalence of hemolysin genes hla, hlb, and hld was higher in the livers ones. The lucocidin genes lukE-lukD was equally prevalent in chicken livers and gizzards isolates. Using spa typing, a subset of the recovered isolates showed that they are not known to be livestock associated and, hence, may be of a human origin. In conclusion, this study stresses the importance of thorough cooking of chicken livers and gizzards since it might contain multidrug resistant enterotoxigenic S. aureus. To our knowledge this is the first study to specifically investigate the prevalence of S. aureus in chicken livers and gizzards in the US.

  5. Computational promoter analysis of mouse, rat and human antimicrobial peptide-coding genes

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    Kai Chikatoshi

    2006-12-01

    Full Text Available Abstract Background Mammalian antimicrobial peptides (AMPs are effectors of the innate immune response. A multitude of signals coming from pathways of mammalian pathogen/pattern recognition receptors and other proteins affect the expression of AMP-coding genes (AMPcgs. For many AMPcgs the promoter elements and transcription factors that control their tissue cell-specific expression have yet to be fully identified and characterized. Results Based upon the RIKEN full-length cDNA and public sequence data derived from human, mouse and rat, we identified 178 candidate AMP transcripts derived from 61 genes belonging to 29 AMP families. However, only for 31 mouse genes belonging to 22 AMP families we were able to determine true orthologous relationships with 30 human and 15 rat sequences. We screened the promoter regions of AMPcgs in the three species for motifs by an ab initio motif finding method and analyzed the derived promoter characteristics. Promoter models were developed for alpha-defensins, penk and zap AMP families. The results suggest a core set of transcription factors (TFs that regulate the transcription of AMPcg families in mouse, rat and human. The three most frequent core TFs groups include liver-, nervous system-specific and nuclear hormone receptors (NHRs. Out of 440 motifs analyzed, we found that three represent potentially novel TF-binding motifs enriched in promoters of AMPcgs, while the other four motifs appear to be species-specific. Conclusion Our large-scale computational analysis of promoters of 22 families of AMPcgs across three mammalian species suggests that their key transcriptional regulators are likely to be TFs of the liver-, nervous system-specific and NHR groups. The computationally inferred promoter elements and potential TF binding motifs provide a rich resource for targeted experimental validation of TF binding and signaling studies that aim at the regulation of mouse, rat or human AMPcgs.

  6. Salmonella enterica serovar enteritidis antimicrobial peptide resistance genes aid in defense against chicken innate immunity, fecal shedding, and egg deposition.

    Science.gov (United States)

    McKelvey, Jessica A; Yang, Ming; Jiang, Yanhua; Zhang, Shuping

    2014-12-01

    Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major etiologic agent of nontyphoid salmonellosis in the United States. S. Enteritidis persistently and silently colonizes the intestinal and reproductive tract of laying hens, resulting in contaminated poultry products. The consumption of contaminated poultry products has been identified as a significant risk factor for human salmonellosis. To understand the mechanisms S. Enteritidis utilizes to colonize and persist in laying hens, we used selective capture of transcribed sequences to identify genes overexpressed in the HD11 chicken macrophage cell line and in primary chicken oviduct epithelial cells. From the 15 genes found to be overexpressed in both cell types, we characterized the antimicrobial peptide resistance (AMPR) genes, virK and ybjX, in vitro and in vivo. In vitro, AMPR genes were required for natural morphology, motility, secretion, defense against detergents such as EDTA and bile salts, and resistance to antimicrobial peptides polymyxin B and avian β-defensins. From this, we inferred the AMPR genes play a role in outer membrane stability and/or modulation. In the intestinal tract, AMPR genes were involved in early intestinal colonization and fecal shedding. In the reproductive tract, virK was required in early colonization whereas a deletion of ybjX caused prolonged ovary colonization and egg deposition. Data from the present study indicate that AMPR genes are differentially utilized in various host environments, which may ultimately assist S. Enteritidis in persistent and silent colonization of chickens.

  7. Identification of antimicrobial resistance genes in multidrug-resistant clinical Bacteroides fragilis isolates by whole genome shotgun sequencing

    DEFF Research Database (Denmark)

    Sydenham, Thomas Vognbjerg; Sóki, József; Hasman, Henrik;

    2015-01-01

    Bacteroides fragilis constitutes the most frequent anaerobic bacterium causing bacteremia in humans. The genetic background for antimicrobial resistance in B. fragilis is diverse with some genes requiring insertion sequence (IS) elements inserted upstream for increased expression. To evaluate whole...... genetic data will most likely require complete or nearly complete genomes. Current approaches to this are laborious and/or costly. Emerging technologies such as nanopore based single DNA strand sensing could perhaps provide a solution in the future....

  8. Antimicrobial Effects of Blueberry, Raspberry, and Strawberry Aqueous Extracts and their Effects on Virulence Gene Expression in Vibrio cholerae.

    Science.gov (United States)

    Khalifa, Hazim O; Kamimoto, Maki; Shimamoto, Toshi; Shimamoto, Tadashi

    2015-11-01

    The antimicrobial effects of aqueous extracts of blueberry, raspberry, and strawberry on 13 pathogenic bacteria were evaluated. The minimum inhibitory concentrations and minimum bactericidal concentrations of the extracts were determined before and after neutralization to pH 7.03 ± 0.15. Both Gram-positive and Gram-negative pathogenic bacteria were selectively inhibited by the non-neutralized berries. Blueberry was the best inhibitor, and Vibrio and Listeria were the most sensitive bacteria. After neutralization, blueberry affected only Vibrio and Listeria, whereas the antimicrobial activities of raspberry and strawberry were abolished. The total contents of phenolics, flavonoids, and proanthocyanidins in the extracts were measured with colorimetric methods and were highest in strawberry, followed by raspberry, and then blueberry. We also studied the effects of sub-bactericidal concentrations of the three berry extracts on virulence gene expression in Vibrio cholerae. Real-time quantitative reverse transcription-polymerase chain reaction revealed that the three berry extracts effectively repressed the transcription of the tcpA gene. Raspberry also repressed the transcription of the ctxA gene, whereas blueberry and strawberry did not. However, the three berry extracts did not affect the transcription of toxT. These results suggest that the three berry extracts exert potent antimicrobial effects and inhibit the expression of the virulence factors of V. cholerae.

  9. The human gut microbiota as a reservoir for antimicrobial resistance genes

    NARCIS (Netherlands)

    Bülow, E.

    2015-01-01

    In the last decades, the emergence and spread of resistant opportunistic pathogens is compromising the effectiveness of antimicrobial therapies. Understanding the emergence and global spread of drug-resistant microorganisms is thus crucial to combat antimicrobial resistance. The human gut harbors a

  10. Whole cell strategies based on lux genes for high throughput applications toward new antimicrobials.

    Science.gov (United States)

    Galluzzi, Lorenzo; Karp, Matti

    2006-08-01

    The discovery/development of novel drug candidates has witnessed dramatic changes over the last two decades. Old methods to identify lead compounds are not suitable to screen wide libraries generated by combinatorial chemistry techniques. High throughput screening (HTS) has become irreplaceable and hundreds of different approaches have been described. Assays based on purified components are flanked by whole cell-based assays, in which reporter genes are used to monitor, directly or indirectly, the influence of a chemical over the metabolism of living cells. The most convenient and widely used reporters for real-time measurements are luciferases, light emitting enzymes from evolutionarily distant organisms. Autofluorescent proteins have been also extensively employed, but proved to be more suitable for end-point measurements, in situ applications - such as the localization of fusion proteins in specific subcellular compartments - or environmental studies on microbial populations. The trend toward miniaturization and the technical advances in detection and liquid handling systems will allow to reach an ultra high throughput screening (uHTS), with 100,000 of compounds routinely screened each day. Here we show how similar approaches may be applied also to the search for new and potent antimicrobial agents.

  11. Butyrate enhances disease resistance of chickens by inducing antimicrobial host defense peptide gene expression.

    Directory of Open Access Journals (Sweden)

    Lakshmi T Sunkara

    Full Text Available Host defense peptides (HDPs constitute a large group of natural broad-spectrum antimicrobials and an important first line of immunity in virtually all forms of life. Specific augmentation of synthesis of endogenous HDPs may represent a promising antibiotic-alternative approach to disease control. In this study, we tested the hypothesis that exogenous administration of butyrate, a major type of short-chain fatty acids derived from bacterial fermentation of undigested dietary fiber, is capable of inducing HDPs and enhancing disease resistance in chickens. We have found that butyrate is a potent inducer of several, but not all, chicken HDPs in HD11 macrophages as well as in primary monocytes, bone marrow cells, and jejuna and cecal explants. In addition, butyrate treatment enhanced the antibacterial activity of chicken monocytes against Salmonella enteritidis, with a minimum impact on inflammatory cytokine production, phagocytosis, and oxidative burst capacities of the cells. Furthermore, feed supplementation with 0.1% butyrate led to a significant increase in HDP gene expression in the intestinal tract of chickens. More importantly, such a feeding strategy resulted in a nearly 10-fold reduction in the bacterial titer in the cecum following experimental infections with S. enteritidis. Collectively, the results indicated that butyrate-induced synthesis of endogenous HDPs is a phylogenetically conserved mechanism of innate host defense shared by mammals and aves, and that dietary supplementation of butyrate has potential for further development as a convenient antibiotic-alternative strategy to enhance host innate immunity and disease resistance.

  12. Involvement of Relish gene from Macrobrachium rosenbergii in the expression of anti-microbial peptides.

    Science.gov (United States)

    Shi, Yan-Ru; Jin, Min; Ma, Fu-Tong; Huang, Ying; Huang, Xin; Feng, Jin-Ling; Zhao, Ling-Ling; Chen, Yi-Hong; Ren, Qian

    2015-10-01

    Relish is an NF-kB transcription factor involved in immune-deficiency (IMD) signal pathway. In this study, a Relish gene (MrRelish) was identified from Macrobrachium rosenbergii. The full length of MrRelish comprises 5072 bp, including a 3510 bp open reading frame encoding a 1169 bp amino acid protein. MrRelish contains a Rel homology domain (RHD), a nucleus localization signal, an IκB-like domain (6 ankyrin repeats), and a death domain. Phylogenetic analysis showed that MrRelish and other Relish from crustaceans belong to one group. MrRelish was expressed in all detected tissues, with the highest expression level in hemocytes and intestines. MrRelish was also upregulated in hepatopancreas at 6 h after Vibrio anguillarum challenge. The over-expression of MrRelish could induce the expression of antimicrobial peptides (AMPs), such as Drosophila Metchnikowin (Mtk), Attacin (Atta), Drosomycin (Drs), and Cecropin (CecA) and shrimp Penaeidin (Pen4). The RNAi of MrRelish in gills showed that the expression of crustin (cru) 2, Cru5, Cru8, lysozyme (Lyso) 1, and Lyso2 was inhibited. However, the expression of anti-lipopolysaccharide factor (ALF) 1 and ALF3 did not change when MrRelish was knocked down. These results indicate that MrRelish may play an important role in innate immune defense against V. anguillarum in M. rosenbergii.

  13. Prevalence of virulence and antimicrobial resistance genes in Salmonella spp. isolated from commercial chickens and human clinical isolates from South Africa and Brazil.

    Science.gov (United States)

    Zishiri, Oliver T; Mkhize, Nelisiwe; Mukaratirwa, Samson

    2016-05-26

    Salmonellosis is a significant public health concern around the world. The injudicious use of antimicrobial agents in poultry production for treatment, growth promotion and prophylaxis has resulted in the emergence of drug resistant strains of Salmonella. The current study was conducted to investigate the prevalence of virulence and antimicrobial resistance genes from Salmonella isolated from South African and Brazilian broiler chickens as well as human clinical isolates. Out of a total of 200 chicken samples that were collected from South Africa 102 (51%) tested positive for Salmonella using the InvA gene. Of the overall 146 Salmonella positive samples that were screened for the iroB gene most of them were confirmed to be Salmonella enterica with the following prevalence rates: 85% of human clinical samples, 68.6% of South African chicken isolates and 70.8% of Brazilian chicken samples. All Salmonella isolates obtained were subjected to antimicrobial susceptibility testing with 10 antibiotics. Salmonella isolates from South African chickens exhibited resistance to almost all antimicrobial agents used, such as tetracycline (93%), trimethoprim-sulfamthoxazole (84%), trimethoprim (78.4%), kanamycin (74%), gentamicin (48%), ampicillin (47%), amoxicillin (31%), chloramphenicol (31%), erythromycin (18%) and streptomycin (12%). All samples were further subjected to PCR in order to screen some common antimicrobial and virulence genes of interest namely spiC, pipD, misL, orfL, pse-1, tet A, tet B, ant (3")-la, sul 1 and sul. All Salmonella positive isolates exhibited resistance to at least one antimicrobial agent; however, antimicrobial resistance patterns demonstrated that multiple drug resistance was prevalent. The findings provide evidence that broiler chickens are colonised by pathogenic Salmonella harbouring antimicrobial resistance genes. Therefore, it is evident that there is a need for prudent use of antimicrobial agents in poultry production systems in order to

  14. Genome-wide identification of genes conferring energy related resistance to a synthetic antimicrobial peptide (Bac8c.

    Directory of Open Access Journals (Sweden)

    Eileen C Spindler

    Full Text Available A fundamental issue in the design and development of antimicrobials is the lack of understanding of complex modes of action and how this complexity affects potential pathways for resistance evolution. Bac8c (RIWVIWRR-NH(2 is an 8 amino acid antimicrobial peptide (AMP that has been shown to have enhanced activity against a range of pathogenic Gram-positive and Gram-negative bacteria, as well as yeast. We have previously demonstrated that Bac8c appears to interfere with multiple targets, at least in part through the disruption of cytoplasmic membrane related functions, and that resistance to this peptide does not easily develop using standard laboratory methods. Here, we applied a genomics approach, SCalar Analysis of Library Enrichement (SCALEs, to map the effect of gene overexpression onto Bac8c resistance in parallel for all genes and gene combinations (up to ∼ 10 adjacent genes in the E. coli genome (a total of ∼ 500,000 individual clones were mapped. Our efforts identified an elaborate network of genes for which overexpression leads to low-level resistance to Bac8c (including biofilm formation, multi-drug transporters, etc. This data was analyzed to provide insights into the complex relationships between mechanisms of action and potential routes by which resistance to this synthetic AMP can develop.

  15. Induction of antimicrobial activities in heterologous streptomycetes using alleles of the Streptomyces coelicolor gene absA1.

    Science.gov (United States)

    McKenzie, Nancy L; Thaker, Maulik; Koteva, Kalinka; Hughes, Donald W; Wright, Gerard D; Nodwell, Justin R

    2010-04-01

    The bacterial genus Streptomyces is endowed with a remarkable secondary metabolism that generates an enormous number of bioactive small molecules. Many of these genetically encoded small molecules are used as antibiotics, anticancer agents and as other clinically relevant therapeutics. The rise of resistant pathogens has led to calls for renewed efforts to identify antimicrobial activities, including expanded screening of streptomycetes. Indeed, it is known that most strains encode >20 secondary metabolites and that many, perhaps most of these, have not been considered for their possible therapeutic use. One roadblock is that many strains do not express their secondary metabolic gene clusters efficiently under laboratory conditions. As one approach to this problem, we have used alleles of a pleiotropic regulator of secondary metabolism from Streptomyces coelicolor to activate secondary biosynthetic gene clusters in heterologous streptomycetes. In one case, we demonstrate the activation of pulvomycin production in S. flavopersicus, a metabolite not previously attributed to this species. We find that the absA1-engineered strains produced sufficient material for purification and characterization. As a result, we identified new, broad-spectrum antimicrobial activities for pulvomycin, including a potent antimicrobial activity against highly antibiotic-resistant Gram-negative and Gram-positive pathogens.

  16. The dlt genes play a role in antimicrobial tolerance of Streptococcus mutans biofilms

    DEFF Research Database (Denmark)

    Nilsson, Carl Martin Peter; Rybtke, Morten; Givskov, Michael;

    2016-01-01

    Microbial biofilms are tolerant to antibiotic treatment and therefore cause problematic infections. Knowledge about the molecular mechanisms underlying biofilm-associated antimicrobial tolerance will aid the development of antibiofilm drugs. Screening of a Streptococcus mutans transposon mutant...

  17. Comparative Genotypes, Staphylococcal Cassette Chromosome mec (SCCmec) Genes and Antimicrobial Resistance amongst Staphylococcus epidermidis and Staphylococcus haemolyticus Isolates from Infections in Humans and Companion Animals

    OpenAIRE

    McManus, Brenda A.; David C Coleman; Deasy, Emily C.; Brennan, Gráinne I.; O’ Connell, Brian; Monecke, Stefan; Ehricht, Ralf; Leggett, Bernadette; Leonard, Nola; Shore, Anna C.

    2015-01-01

    This study compares the characteristics of Staphylococcus epidermidis (SE) and Staphylococcus haemolyticus (SH) isolates from epidemiologically unrelated infections in humans (Hu) (28 SE-Hu; 8 SH-Hu) and companion animals (CpA) (12 SE-CpA; 13 SH-CpA). All isolates underwent antimicrobial susceptibility testing, multilocus sequence typing and DNA microarray profiling to detect antimicrobial resistance and SCCmec-associated genes. All methicillin-resistant (MR) isolates (33/40 SE, 20/21 SH) und...

  18. CHARACTERIZATION OF VIRULENCE GENES AND ANTIMICROBIAL RESISTANCE OF LUNG PATHOGENIC ESCHERICHIA COLI ISOLATES IN FOREST MUSK DEER (MOSCHUS BEREZOVSKII).

    Science.gov (United States)

    Luo, Xi; Wang, Peng; Cheng, Jian-guo; Luo, Yan; Dai, Lei; Zhou, Xin; Zou, Li-kou; Li, Bei; Xiao, Jiu-Jin

    2016-06-01

    This study investigated genotypic diversity, 26 virulence genes, and antimicrobial susceptibility of lung pathogenic Escherichia coli (LPEC) isolated from forest musk deer. Associations between virulence factors (VFs) and phylogenetic group, between antimicrobial resistance (AMR) and phylogenetic group, and between AMR and VFs were subsequently assessed. The results showed 30 LPEC isolated were grouped into seven different clusters (A, B, C, D, E, F, and G). The detection rates of crl (90%), kpsMT II (76.67%), mat (76.67%), and ompA (80%) were over 75%. The most frequent types of resistance were to amoxicillin (100%), sulfafurazole (100%), ampicillin (96.67%), and tetracycline (96.67%), with 93.33% (n = 28) of isolates resistant to more than eight types of drugs. There were significant relationships between resistance to cefalotin and the presence of iucD(a) (P < 0.001), papC (P = 0.032), and kpsMT II (P = 0.028); between resistance to chloromycetin and the presence of irp2 (P = 0.004) and vat (P = 0.047); between resistance to nalidixic acid and the presence of crl (P = 0.002) and iucD(a) (P = 0.004); and between resistance to ampicillin/sulbactam and the presence of vat (P = 0.013). These results indicated there could be some association between resistance and VFs, and there is a great need for the prudent use of antimicrobial agents in LPEC.

  19. Development of a miniaturised microarray-based assay for the rapid identification of antimicrobial resistance genes in Gram-negative bacteria

    NARCIS (Netherlands)

    Batchelor, M.; Hopkins, K.L.; Liebana, E.; Slickers, P.; Ehricht, R.; Mafura, M.; Aerestrup, F.; Mevius, D.J.; Clifton-Hadley, F.A.; Woodward, M.; Davies, R.; Threlfall, J.; Anjum, F.M.

    2008-01-01

    We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and ß-lactams, including extended-spectrum ß-lact

  20. [Enhanced resistance to phytopathogenic bacteria in transgenic tobacco plants with synthetic gene of antimicrobial peptide cecropin P1].

    Science.gov (United States)

    Zakharchenko, N S; Rukavtsova, E B; Gudkov, A T; Bur'ianov, Ia I

    2005-11-01

    Plasmids with a synthetic gene of the mammalian antimicrobial peptide cecropin P1 (cecP1) controlled by the constitutive promoter 35S RNA of cauliflower mosaic virus were constructed. Agrobacterial transformation of tobacco plants was conducted using the obtained recombinant binary vector. The presence of gene cecP1 in the plant genome was confirmed by PCR. The expression of gene cecP1 in transgenic plants was shown by Northern blot analysis. The obtained transgenic plants exhibit enhanced resistance to phytopathogenic bacteria Pseudomonas syringae, P. marginata, and Erwinia carotovora. The ability of transgenic plants to express cecropin P1 was transmitted to the progeny. F1 and F2 plants had the normal phenotype (except for a changed coloration of flowers) and retained the ability to produce normal viable seeds upon self-pollination. Lines of F1 plants with Mendelian segregation of transgenic traits were selected.

  1. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus.

    Science.gov (United States)

    Gottschalk, Sanne; Gottlieb, Caroline T; Vestergaard, Martin; Hansen, Paul R; Gram, Lone; Ingmer, Hanne; Thomsen, Line E

    2015-12-01

    The rapid rise in antibiotic-resistant pathogens is causing increased health concerns, and consequently there is an urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs), which have been isolated from a wide range of organisms, represent a very promising class of novel antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl(2) concentrations and at alkaline pH, while it was compromised by acidic pH and exposure to serum. Furthermore, at subinhibitory concentrations of FL9, S. aureus responded by increasing the expression of two major virulence factor genes, namely the regulatory rnaIII and hla, encoding α-haemolysin. In addition, the S. aureus-encoded natural tolerance mechanisms included peptide cleavage and the addition of positive charge to the cell surface, both of which minimized the antimicrobial activity of FL9. Our results add new information about FL9 and its effect on S. aureus, which may aid in the future development of analogues with improved therapeutic potential.

  2. Characterization of antimicrobial resistance and virulence genes in Enterococcus spp. isolated from retail meats in Alberta, Canada.

    Science.gov (United States)

    Aslam, Mueen; Diarra, Moussa S; Checkley, Sylvia; Bohaychuk, Valerie; Masson, Luke

    2012-06-01

    The objective of this study was to characterize antimicrobial resistance (AMR) and virulence genotypes of Enterococcus spp. particularly Enterococcus faecalis isolated from retail meats purchased (2007-2008) in Alberta, Canada. Unconditional statistical associations between AMR pheno- and genotypes and virulence genotypes were determined. A total of 532 enterococci comprising one isolate from each positive sample were analyzed for antimicrobial susceptibility. A customized enterococcal microarray was used for species identification and the detection of AMR and virulence genes. E. faecalis was found in >94% of poultry samples and in about 73% of beef and 86% of pork samples. Enterococcus faecium was not found in turkey meat and its prevalence was 2% in beef and pork and 4% in chicken samples. None of the enterococci isolates were resistant to the clinically important drugs ciprofloxacin, daptomycin, linezolid and vancomycin. Multiresistance (≥3 antimicrobials) was more common in E. faecalis (91%) isolated from chicken and turkey (91%) than those isolated from beef (14%) or pork (45%). Resistance to aminoglycosides was also noted at varying degrees. The most common resistance genes found in E. faecalis were aminoglycosides (aac, aphA3, aadE, sat4, aadA), macrolides (ermB, ermA), tetracyclines (tetM, tetL, tetO), streptogramin (vatE), bacitracin (bcrR) and lincosamide (linB). Virulence genes expressing aggregation substances (agg) and cytolysin (cylA, cylB, cylL, cylM) were found more frequently in poultry E. faecalis and were unconditionally associated with tetM, linB and bcrR resistance genes. Other virulence genes coding for adhesion (ace, efaAfs), gelatinase (gelE) were also found in the majority of E. faecalis. Significant statistical associations were found between resistance and virulence genotypes, suggesting their possible physical link on a common genetic element. This study underscores the importance of E. faecalis as a reservoir of resistance and

  3. Tolerance to the antimicrobial peptide colistin in Pseudomonas aeruginosa biofilms is linked to metabolically active cells, and depends on the pmr and mexAB-oprM genes.

    Science.gov (United States)

    Pamp, Sünje Johanna; Gjermansen, Morten; Johansen, Helle Krogh; Tolker-Nielsen, Tim

    2008-04-01

    Bacteria living as biofilm are frequently reported to exhibit inherent tolerance to antimicrobial compounds, and might therefore contribute to the persistence of infections. Antimicrobial peptides are attracting increasing interest as new potential antimicrobial therapeutics; however, little is known about potential mechanisms, which might contribute to resistance or tolerance development towards these compounds in biofilms. Here we provide evidence that a spatially distinct subpopulation of metabolically active cells in Pseudomonas aeruginosa biofilms is able to develop tolerance to the antimicrobial peptide colistin. On the contrary, biofilm cells exhibiting low metabolic activity were killed by colistin. We demonstrate that the subpopulation of metabolically active cells is able to adapt to colistin by inducing a specific adaptation mechanism mediated by the pmr operon, as well as an unspecific adaptation mechanism mediated by the mexAB-oprM genes. Mutants defective in either pmr-mediated lipopolysaccharide modification or in mexAB-oprM-mediated antimicrobial efflux were not able to develop a tolerant subpopulation in biofilms. In contrast to the observed pattern of colistin-mediated killing in biofilms, conventional antimicrobial compounds such as ciprofloxacin and tetracycline were found to specifically kill the subpopulation of metabolically active biofilm cells, whereas the subpopulation exhibiting low metabolic activity survived the treatment. Consequently, targeting the two physiologically distinct subpopulations by combined antimicrobial treatment with either ciprofloxacin and colistin or tetracycline and colistin almost completely eradicated all biofilm cells.

  4. Investigation of antibacterial activity of Bacillus spp. isolated from the feces of Giant Panda and characterization of their antimicrobial gene distributions.

    Science.gov (United States)

    Zhou, Ziyao; Zhou, Xiaoxiao; Zhong, Zhijun; Wang, Chengdong; Zhang, Hemin; Li, Desheng; He, Tingmei; Li, Caiwu; Liu, Xuehan; Yuan, Hui; Ji, Hanli; Luo, Yongjiu; Gu, Wuyang; Fu, Hualin; Peng, Guangneng

    2014-12-01

    Bacillus group is a prevalent community of Giant Panda's intestinal flora, and plays a significant role in the field of biological control of pathogens. To understand the diversity of Bacillus group from the Giant Panda intestine and their functions in maintaining the balance of the intestinal microflora of Giant Panda, this study isolated a significant number of strains of Bacillus spp. from the feces of Giant Panda, compared the inhibitory effects of these strains on three common enteric pathogens, investigated the distributions of six universal antimicrobial genes (ituA, hag, tasA, sfp, spaS and mrsA) found within the Bacillus group by PCR, and analyzed the characterization of antimicrobial gene distributions in these strains using statistical methods. The results suggest that 34 strains of Bacillus spp. were isolated which has not previously been detected at such a scale, these Bacillus strains could be classified into five categories as well as an external strain by 16S rRNA; Most of Bacillus strains are able to inhibit enteric pathogens, and the antimicrobial abilities may be correlated to their categories of 16S rRNA; The detection rates of six common antimicrobial genes are between 20.58 %(7/34) and 79.41 %(27/34), and genes distribute in three clusters in these strains. We found that the antimicrobial abilities of Bacillus strains can be one of the mechanisms by which Giant Panda maintains its intestinal microflora balance, and may be correlated to their phylogeny.

  5. Antimicrobial resistance gene detection in beneficial and pathogenic food related bacteria

    NARCIS (Netherlands)

    van Hoek, A.H.A.M.

    2009-01-01

    Although, the discovery of antibiotics has revolutionised the treatment of infections, the growing phenomenon of bacterial resistance, among others due to the use and abuse of antimicrobial agents, is now threatening to take us back to a pre-antibiotic era. Continuously, microorganisms subtly change

  6. Antimicrobial susceptibility and occurrence of resistance genes among Salmonella enterica serovar Weltevreden from different countries

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Lertworapreecha, M.; Evans, M.C.;

    2003-01-01

    Objectives: This study was conducted to investigate the occurrence of antimicrobial resistance among Salmonella Weltevreden isolates from different sources in South-East Asia (Indonesia, Laos, Malaysia, Taiwan, Thailand, Vietnam), Australia, Denmark, New Zealand and the USA. Methods: A total of 503...

  7. [Transgenic Belarussian-bred potato plants expressing genes for antimicrobial peptides of the cecropin-melittin type].

    Science.gov (United States)

    Vutto, N L; Gapeeva, T A; Pundik, A N; Tret'iakova, T G; Volotovskiĭ, I D

    2010-12-01

    Binary vectors for Agrobacterium-mediated transformation were constructed to express the genes for antimicrobial peptides (APs) of the cectropin-melittin type under the control of the cauliflower mosaic virus 35S RNA promoter in plants. It was shown with Escherichia coli and Agrobacterium tumefaciens cells that the cassettes could be cloned in pB1121-based vectors with deletion of the 3-D-glycuronidase gene only in the orientation opposite to that of the original vector. Transgenic potato plants were obtained using the Belarussian varieties Odyssey, Vetraz, and Scarb. Their cells expressed the MsrA1 or CEMA peptides of the cecropin-melittin type. The expression was shown to confer higher resistance to bacterial (Erwinia carotovora) infection and extremely high resistance to fungal (Phytophtora infestans and Alternarla solani) infections.

  8. Evaluation of feeding distiller's grains, containing virginiamycin, on antimicrobial susceptibilities in fecal isolates of Enterococcus and Escherichia coli and prevalence of resistance genes in cattle.

    Science.gov (United States)

    Edrington, T S; Bischoff, K M; Loneragan, G H; Nisbet, D J

    2014-03-01

    Dried distiller's grains (DG) produced from ethanol fermentations dosed with 0 (control), 2, or 20 mg/kg virginiamycin-based product or spiked with virginiamycin (VM) postfermentation were fed to cattle and effects on antimicrobial susceptibility, and prevalence of antimicrobial resistance genes in commensal bacteria was examined. Biological activity assays of DG (from each fermentation) indicated a concentration of 0, 0.7, and 8.9 mg/kg VM, respectively. Twenty-four crossbred beef steers were fed 1 of 4 diets (containing 8% of each of the different batches of DG) and a fourth using 8% of the control DG (0 mg/kg VM) + 0.025 g/kg V-Max50 (positive control) for 7 wk. Fecal samples were collected weekly throughout the experimental period and cultured for Escherichia coli and Enterococcus, and isolates were examined for antimicrobial susceptibility, antimicrobial resistance genes (vatE, ermB, and msrC in Enterococcus), and integrons (E. coli). No treatment differences (P > 0.05) were observed in antimicrobial susceptibility of the E. coli isolates. Enterococcus isolates were resistant to more antimicrobials; however, this was influenced by the species of Enterococcus and not treatment (P > 0.10). The prevalence of ermB was greater (P < 0.05) in the control isolates after 4 and 6 wk while at wk 7, prevalence was greater (P < 0.01) in the 0.7 and 8.9 mg/kg VM treatments. Taken together, the minor treatment differences observed for the presence of ermB coupled with the lack of effect on antimicrobial susceptibility patterns suggest that feeding DG containing VM residues should have minimal if any impact on prevalence of antimicrobial resistance.

  9. Presence of superantigen genes and antimicrobial resistance in Staphylococcus isolates obtained from the uteri of dairy cows with clinical endometritis.

    Science.gov (United States)

    Zhao, J-L; Ding, Y-X; Zhao, H-X; He, X-L; Li, P-F; Li, Z-F; Guan, H; Guo, X

    2014-10-11

    Clinical endometritis is an important disease of dairy cattle and results in decreased reproductive performance. This disease is caused by contamination of the uterus with a broad spectrum of microorganisms after calving. In this study, staphylococcal isolates from the uterus of dairy cows with clinical endometritis were tested for their distribution of superantigen (SAg) genes and antimicrobial resistance. Between the 127 staphylococcal isolates collected in this study, 10 species were identified. The predominant strain identified was Staphylococcus aureus (n=53), followed by Staphylococcus saprophyticus (n=38) and Staphylococcus chromogenes (n=22). PCR analysis demonstrated that most isolates (63.0 per cent) harboured at least one SAg gene. The most commonly observed SAg gene and genotype was selj (38.6 per cent) and sec-selj-seln (24.0 per cent), respectively. Most isolates were resistant to penicillin (79.5 per cent), ampicillin (71.7 per cent), erythromycin (56.7 per cent), and tetracycline (52.0 per cent). PCR analysis demonstrated that the antimicrobial resistance determinants ermA, ermB, ermC, tetK, tetM and blaZ were detected in 0 per cent, 44.4 per cent, 51.4 per cent, 68.2 per cent, 13.6 per cent and 86.1 per cent of the erythromycin, tetracycline and β-lactam resistant isolates, respectively. There were 22 (17.3 per cent of all isolates) coagulase-negative staphylococci shown to be methicillin resistant. In the methicillin-resistant isolates, significant resistances to ampicillin, erythromycin and penicillin were observed (P<0.01). The results of this study demonstrate that staphylococci recovered from dairy cows with clinical endometritis contain an extensive and complex prevalence of SAg genes. Significant resistances to antibiotics were also seen, highlighting the need for the rational appliance of antibiotics in veterinary medicine.

  10. Genotypes, Virulence Factors and Antimicrobial Resistance Genes of Staphylococcus aureus Isolated in Bovine Subclinical Mastitis from Eastern China

    Directory of Open Access Journals (Sweden)

    Javed Memon§, Yongchun Yang§, Jam Kashifa, Muhammad Yaqoob, Rehana Buriroa, Jamila Soomroa, Wang Liping and Fan Hongjie*

    2013-11-01

    Full Text Available This study was carried out to determine the genotypes, virulence factors and antimicrobial resistance traits of 34 Staphylococcus aureus isolated from subclinical mastitis in Eastern China. Minimal inhibitory concentration (MIC results showed resistance to erythromycin in all isolates. A high frequency of Methicillin resistant S. aureus (MRSA; 29% was observed and these isolates were also highly resistant to penicillin, oxacillin, oxytetracycline and chloramphenicol than methicillin sensitive S. aureus (MSSA isolates. Thirteen pathogenic factors and seven resistance genes including mecA and blaZ gene were checked through PCR. The spaX gene was found in all isolates, whereas cna, spaIg, nuc, clfA, fnbpB, hlA, hlB and seA were present in 35, 79, 85, 59, 35, 85, 71 and 38% isolates, respectively. Nine isolates carried a group of 8 different virulence genes. Moreover, macrolide resistance genes ermB and ermC were present in all isolates. High resistance rate against methicillin was found but no isolate was positive for mecA gene, whereas blaZ and tetK were detected in 82 and 56% isolates, respectively. Genes; fnbpA, seB, seC, seD, dfrK and tetM were not found in any isolate. The statistical association between phenotypic resistance and virulence genes showed, clfA, fnbpB, hlB and seA, were potentially associated with penicillin G, ciprofloxacin, methicillin, chloramphenicol, trimethoprim and oxytetracycline resistance (P≤0.05. REP-PCR based genotyping showed seven distinct genotypes (A-G prevalent in this region. This study reports the presence of multidrug resistant S. aureus in sub-clinical mastitis which were also highly virulent that could be a major obstacle in the treatment of mastitis in this region of China.

  11. Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding

    Directory of Open Access Journals (Sweden)

    Tiane Martin de Moura

    2012-10-01

    Full Text Available INTRODUCTION: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS and coagulasepositive (CoPS isolates from black pudding in southern Brazil. METHODS: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa and enterotoxin (se genes was investigated by polymerase chain reaction. RESULTS: The isolates were divided into 2 groups: 75.6% (62/82 were CoNS and 24.4% (20/82 were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8% and Staphylococcus carnosus (15.9% were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82 of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6% and seb (27.5%. CONCLUSIONS: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

  12. Loss of DNase II function in the gonad is associated with a higher expression of antimicrobial genes in Caenorhabditis elegans.

    Science.gov (United States)

    Yu, Hsiang; Lai, Huey-Jen; Lin, Tai-Wei; Chen, Chang-Shi; Lo, Szecheng J

    2015-08-15

    Three waves of apoptosis shape the development of Caenorhabditis elegans. Although the exact roles of the three DNase II genes (nuc-1, crn-6 and crn-7), which are known to mediate degradation of apoptotic DNA, in the embryonic and larval phases of apoptosis have been characterized, the DNase II acting in the third wave of germ cell apoptosis remains undetermined. In the present study, we performed in vitro and in vivo assays on various mutant nematodes to demonstrate that NUC-1 and CRN-7, but not CRN-6, function in germ cell apoptosis. In addition, in situ DNA-break detection and anti-phosphorylated ERK (extracellular-signal-regulated kinase) staining illustrated the sequential and spatially regulated actions of NUC-1 and CRN-7, at the pachytene zone of the gonad and at the loop respectively. In line with the notion that UV-induced DNA fragment accumulation in the gonad activates innate immunity responses, we also found that loss of NUC-1 and CRN-7 lead to up-regulation of antimicrobial genes (abf-2, spp-1, nlp-29, cnc-2, and lys-7). Our observations suggest that an incomplete digestion of DNA fragments resulting from the absence of NUC-1 or CRN-7 in the gonad could induce the ERK signalling, consequently activating antimicrobial gene expression. Taken together, the results of the present study demonstrate for the first time that nuc-1 and crn-7 play a role in degrading apoptotic DNA in distinct sites of the gonad, and act as negative regulators of innate immunity in C. elegans.

  13. Impact of UV and peracetic acid disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli in wastewater effluents.

    Science.gov (United States)

    Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke; Frigon, Dominic

    2014-06-01

    Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm(2) and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters.

  14. Antimicrobial susceptibility and presence of resistance genes in staphylococci from poultry

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Agersø, Yvonne; Ahrens, Peter

    2000-01-01

    to ciprofloxacin. Only six (7%) S. aureus isolates and one Staphylococcus saprophyticus were penicillin resistant. Resistance to sulphamethoxazole was observed among 16 (19%) of S. aureus isolates and two coagulase negative staphylococci (CNS). Twenty (24%) of the S. aureus isolates were resistant to erythromycin...... of conventional biochemical testing and 16S rDNA sequencing. The most common species were Staphylococcus aureus (83), Staphylococcus hyicus (11), Staphylococcus xylosus (9) and Staphylococcus cohnii (6). The isolates were susceptible to most antimicrobials tested. A high frequency of S. aureus (30%) was resistant...

  15. Antimicrobial susceptibility, tetracycline and erythromycin resistance genes, and multilocus sequence typing of Streptococcus suis isolates from diseased pigs in China.

    Science.gov (United States)

    Chen, Lei; Song, Yajing; Wei, Zigong; He, Hongkui; Zhang, Anding; Jin, Meilin

    2013-01-01

    Streptococcus suis (S. suis) is an emerging zoonotic pathogen causing significant economic losses in the swine industry. Here, we investigated the antimicrobial susceptibility, associated antibiotic-resistant determinants and sequence type (ST) of S. suis isolates from diseased pigs in China from 2008 to 2010. Serotype 2 was the most frequently observed strain (n=95) among the 106 S. suis strains collected, followed by serotypes 3 (n=3), 5 (n=3), 4 (n=2), 7 (n=1), 11 (n=1) and 28 (n=1). Multilocus sequence typing analysis revealed that ST1 (n=21) and ST7 (n=74) were the predominant STs, and serotype 2 was found to be significantly correlated with ST7 (P=0.017, Fisher's exact test) and CC1 (P=0.024, Fisher's exact test). The antimicrobial susceptibility results indicated that the antibiotic resistance rate was highest for tetracycline (99.1%), followed by azithromycin (68.9%), erythromycin (67.9%), clindamycin (67.9%), trimethoprim/sulfamethoxazole (16%), levofloxacin (2.8%), chloramphenicol (1.9%), cefaclor (0.9%) and ceftriaxone (0.9%). Antibiotic-resistant genes tet(M), tet(O), tet(O/W/32/O), tet(O/32/O), tet(S), tet(W), tet(L), tet(40), erm(B), mef(A/E) and msr(D) could be detected, and several tandem organizations of antibiotic resistance genes were also found in this study. In conclusion, S. suis strains isolated from diseased pigs in China were less diverse and multi-drug resistant.

  16. Pathogen-induced expression of a cecropin A-melittin antimicrobial peptide gene confers antifungal resistance in transgenic tobacco.

    Science.gov (United States)

    Yevtushenko, Dmytro P; Romero, Rafael; Forward, Benjamin S; Hancock, Robert E; Kay, William W; Misra, Santosh

    2005-06-01

    Expression of defensive genes from a promoter that is specifically activated in response to pathogen invasion is highly desirable for engineering disease-resistant plants. A plant transformation vector was constructed with transcriptional fusion between the pathogen-responsive win3.12T promoter from poplar and the gene encoding the novel cecropin A-melittin hybrid peptide (CEMA) with strong antimicrobial activity. This promoter-transgene combination was evaluated in transgenic tobacco (Nicotiana tabacum L. cv. Xanthi) for enhanced plant resistance against a highly virulent pathogenic fungus Fusarium solani. Transgene expression in leaves was strongly increased after fungal infection or mechanical wounding, and the accumulation of CEMA transcripts was found to be systemic and positively correlated with the number of transgene insertions. A simple and efficient in vitro regeneration bioassay for preliminary screening of transgenic lines against pathogenic fungi was developed. CEMA had strong antifungal activity in vitro, inhibiting conidia germination at concentrations that were non-toxic to tobacco protoplasts. Most importantly, the expression level of the CEMA peptide in vivo, regulated by the win3.12T promoter, was sufficient to confer resistance against F. solani in transgenic tobacco. The antifungal resistance of plants with high CEMA expression was strong and reproducible. In addition, leaf tissue extracts from transgenic plants significantly reduced the number of fungal colonies arising from germinated conidia. Accumulation of CEMA peptide in transgenic tobacco had no deleterious effect on plant growth and development. This is the first report showing the application of a heterologous pathogen-inducible promoter to direct the expression of an antimicrobial peptide in plants, and the feasibility of this approach to provide disease resistance in tobacco and, possibly, other crops.

  17. Tolerance to the antimicrobial peptide colistin in Pseudomonas aeruginosa biofilms is linked to metabolically active cells, and depends on the pmr and mexAB-oprM genes

    DEFF Research Database (Denmark)

    Pamp, Sünje Johanna; Gjermansen, Morten; Johansen, Helle Krogh

    2008-01-01

    to the antimicrobial peptide colistin. On the contrary, biofilm cells exhibiting low metabolic activity were killed by colistin. We demonstrate that the subpopulation of metabolically active cells is able to adapt to colistin by inducing a specific adaptation mechanism mediated by the pmr operon, as well...... as an unspecific adaptation mechanism mediated by the mexAB-oprM genes. Mutants defective in either pmr-mediated lipopolysaccharide modification or in mexAB-oprM-mediated antimicrobial efflux were not able to develop a tolerant subpopulation in biofilms. In contrast to the observed pattern of colistin...

  18. Typing of Campylobacter jejuni Isolated from Turkey by Genotypic Methods, Antimicrobial Susceptibility, and Virulence Gene Patterns: A Retrospective Study.

    Science.gov (United States)

    Manfreda, Gerardo; Parisi, Antonio; De Cesare, Alessandra; Mion, Domenico; Piva, Silvia; Zanoni, Renato G

    2016-02-01

    In this retrospective study, typing ability, discriminatory power, and concordance between typing results obtained on 123 Campylobacter jejuni turkey isolates, collected in 1998, within 14 different farms, applying multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), antibiotic resistance profile, and virulence gene pattern, were assessed and compared. Overall, 33 sequence types, 28 pulsotypes, 10 resistotypes, and 5 pathotypes were identified. MLST and PFGE showed the better discriminatory ability (i.e., Simpson's diversity index >0.90) as well as unidirectional (i.e., Wallace and adjusted Wallace coefficients >0.86) and bidirectional (i.e., adjusted Rand coefficient >0.60) concordance. Moreover, both methods showed a good unidirectional and bidirectional concordance with the resistotype. On the contrary, the congruence of both genotyping methods and resistotype with the pathotype seemed due to chance alone. A clonal relationship was identified among 66.7% of the isolates. Furthermore, 59.7% of the investigated isolates were resistant to two or more antimicrobials and 92% to tetracycline. All the isolates harbored cadF and pldA genes, whereas a flaA gene product and a cdtB gene product were amplified from 85.4% and 79.7% of the isolates, respectively, using the primers designed by Bang et al. (2003). The results of this study clarify the level of genetic diversity among the C. jejuni originating from turkeys. MLST level of correlation with PFGE, resistotype, and pathotype is assessed. This result supports the selection of type and number of typing methods to use in epidemiological studies. Finally, the identification of clonal complexes (i.e., groups of profiles differing by no more than one gene from at least one other profile of the group using the entire Campylobacter MLST database) shared between turkey and human isolates suggests that turkeys could be a possible source of Campylobacter infection.

  19. Comparison of innate immune agonists for induction of tracheal antimicrobial peptide gene expression in tracheal epithelial cells of cattle.

    Science.gov (United States)

    Berghuis, Lesley; Abdelaziz, Khaled Taha; Bierworth, Jodi; Wyer, Leanna; Jacob, Gabriella; Karrow, Niel A; Sharif, Shayan; Clark, Mary Ellen; Caswell, Jeff L

    2014-10-12

    Bovine respiratory disease is a complex of bacterial and viral infections of economic and welfare importance to the beef industry. Although tracheal antimicrobial peptide (TAP) has microbicidal activity against bacterial pathogens causing bovine respiratory disease, risk factors for bovine respiratory disease including BVDV and stress (glucocorticoids) have been shown to inhibit the induced expression of this gene. Lipopolysaccharide is known to stimulate TAP gene expression, but the maximum effect is only observed after 16 h of stimulation. The present study investigated other agonists of TAP gene expression in primary cultures of bovine tracheal epithelial cells. PCR analysis of unstimulated tracheal epithelial cells, tracheal tissue and lung tissue each showed mRNA expression for Toll-like receptors (TLRs) 1-10. Quantitative RT-PCR analysis showed that Pam3CSK4 (an agonist of TLR1/2) and interleukin (IL)-17A significantly induced TAP gene expression in tracheal epithelial cells after only 4-8 h of stimulation. Flagellin (a TLR5 agonist), lipopolysaccharide and interferon-α also had stimulatory effects, but little or no response was found with class B CpG ODN 2007 (TLR9 agonist) or lipoteichoic acid (TLR2 agonist). The use of combined agonists had little or no enhancing effect above that of single agonists. Thus, Pam3CSK4, IL-17A and lipopolysaccharide rapidly and significantly induce TAP gene expression, suggesting that these stimulatory pathways may be of value for enhancing innate immunity in feedlot cattle at times of susceptibility to disease.

  20. Structure-Function Relationships of Antimicrobial Peptides and Proteins with Respect to Contact Molecules on Pathogen Surfaces

    NARCIS (Netherlands)

    Zhang, Ruiyan; Eckert, Thomas; Lutteke, Thomas; Hanstein, Stefan; Scheidig, Axel; Bonvin, Alexandre M J J; Nifantiev, Nikolay E; Kozar, Tibor; Schauer, Roland; Enani, Mushira Abdulaziz; Siebert, Hans-Christian

    2016-01-01

    The Antimicrobial peptides (e.g. defensins, hevein-like molecules and food-protecting peptides like nisin) are able to interact specifically with contact structures on pathogen surfaces. Besides protein receptors, important recognition points for such contacts are provided by pathogen glycan chains

  1. Antimicrobial resistance and virulence-associated genes of Salmonella enterica subsp. enterica serotypes Muenster, Florian, Omuna, and Noya strains isolated from clinically diarrheic humans in Egypt.

    Science.gov (United States)

    Osman, Kamelia M; Marouf, Sherif H; Alatfeehy, Nayerah

    2013-10-01

    Four serotypes recovered from clinically diarrheic human faecal samples (Salmonella Muenster, Salmonella Florian, Salmonella Omuna and Salmonella Noya) were investigated for the presence of 11 virulence genes (invA, avrA, ssaQ, mgtC, siiD, sopB, gipA, sodC1, sopE1, spvC, and bcfC) and their association with antibiotic resistance. The 4 Salmonella serotypes lacked virulence genes gipA and spvC. Resistance to 7 of the 14 antimicrobials was detected. The frequency of resistance, to lincomycin and streptomycin (100% of the Salmonella Muenster [2/5], Salmonella Florian [1/5], Salmonella Omuna [1/5], and Salmonella Noya [1/5] isolates), chloramphenicol (100% of the Salmonella Muenster [2/5] and Salmonella Florian [1/5] isolates) and trimethoprim-sulfamethoxazole (100% of the Salmonella Florian [1/5] and Salmonella Omuna [1/5] isolates) was an outstanding feature. With the rest of the antibiotics, the four Salmonella serotypes exhibited a great diversity in their resistance patterns. Overall, the four Salmonella serotypes were resistant to more than one antimicrobial. The antimicrobials to which the Salmonella Muenster, Salmonella Florian, and Salmonella Omuna isolates were resistant, contributed to five different antimicrobial resistance profiles. The virulence associated genes invA, ssaQ, siiD, sopB, and bcfC genes were 100% associated with certain antimicrobial resistance phenotypes (streptomycin and lincosamide) not recorded previously, and secondly, the presence of invA, avrA, ssaQ, mgtC, siiD, sopB, and bcfC was associated with resistance to chloramphenicol. The results of this study will help in understanding the spread of virulence genotypes and antibiotic resistance in Salmonella in the region of study.

  2. Cloning and Expression of Synthetic Genes Encoding the Broad Antimicrobial Spectrum Bacteriocins SRCAM 602, OR-7, E-760, and L-1077, by Recombinant Pichia pastoris

    Science.gov (United States)

    Jiménez, Juan J.; Gútiez, Loreto; Cintas, Luis M.; Herranz, Carmen; Hernández, Pablo E.

    2015-01-01

    We have evaluated the cloning and functional expression of previously described broad antimicrobial spectrum bacteriocins SRCAM 602, OR-7, E-760, and L-1077, by recombinant Pichia pastoris. Synthetic genes, matching the codon usage of P. pastoris, were designed from the known mature amino acid sequence of these bacteriocins and cloned into the protein expression vector pPICZαA. The recombinant derived plasmids were linearized and transformed into competent P. pastoris X-33, and the presence of integrated plasmids into the transformed cells was confirmed by PCR and sequencing of the inserts. The antimicrobial activity, expected in supernatants of the recombinant P. pastoris producers, was purified using a multistep chromatographic procedure including ammonium sulfate precipitation, desalting by gel filtration, cation exchange-, hydrophobic interaction-, and reverse phase-chromatography (RP-FPLC). However, a measurable antimicrobial activity was only detected after the hydrophobic interaction and RP-FPLC steps of the purified supernatants. MALDI-TOF MS analysis of the antimicrobial fractions eluted from RP-FPLC revealed the existence of peptide fragments of lower and higher molecular mass than expected. MALDI-TOF/TOF MS analysis of selected peptides from eluted RP-FPLC samples with antimicrobial activity indicated the presence of peptide fragments not related to the amino acid sequence of the cloned bacteriocins. PMID:25821820

  3. Cloning and expression of synthetic genes encoding the broad antimicrobial spectrum bacteriocins SRCAM 602, OR-7, E-760, and L-1077, by recombinant Pichia pastoris.

    Science.gov (United States)

    Arbulu, Sara; Jiménez, Juan J; Gútiez, Loreto; Cintas, Luis M; Herranz, Carmen; Hernández, Pablo E

    2015-01-01

    We have evaluated the cloning and functional expression of previously described broad antimicrobial spectrum bacteriocins SRCAM 602, OR-7, E-760, and L-1077, by recombinant Pichia pastoris. Synthetic genes, matching the codon usage of P. pastoris, were designed from the known mature amino acid sequence of these bacteriocins and cloned into the protein expression vector pPICZαA. The recombinant derived plasmids were linearized and transformed into competent P. pastoris X-33, and the presence of integrated plasmids into the transformed cells was confirmed by PCR and sequencing of the inserts. The antimicrobial activity, expected in supernatants of the recombinant P. pastoris producers, was purified using a multistep chromatographic procedure including ammonium sulfate precipitation, desalting by gel filtration, cation exchange-, hydrophobic interaction-, and reverse phase-chromatography (RP-FPLC). However, a measurable antimicrobial activity was only detected after the hydrophobic interaction and RP-FPLC steps of the purified supernatants. MALDI-TOF MS analysis of the antimicrobial fractions eluted from RP-FPLC revealed the existence of peptide fragments of lower and higher molecular mass than expected. MALDI-TOF/TOF MS analysis of selected peptides from eluted RP-FPLC samples with antimicrobial activity indicated the presence of peptide fragments not related to the amino acid sequence of the cloned bacteriocins.

  4. Cloning and Expression of Synthetic Genes Encoding the Broad Antimicrobial Spectrum Bacteriocins SRCAM 602, OR-7, E-760, and L-1077, by Recombinant Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Sara Arbulu

    2015-01-01

    Full Text Available We have evaluated the cloning and functional expression of previously described broad antimicrobial spectrum bacteriocins SRCAM 602, OR-7, E-760, and L-1077, by recombinant Pichia pastoris. Synthetic genes, matching the codon usage of P. pastoris, were designed from the known mature amino acid sequence of these bacteriocins and cloned into the protein expression vector pPICZαA. The recombinant derived plasmids were linearized and transformed into competent P. pastoris X-33, and the presence of integrated plasmids into the transformed cells was confirmed by PCR and sequencing of the inserts. The antimicrobial activity, expected in supernatants of the recombinant P. pastoris producers, was purified using a multistep chromatographic procedure including ammonium sulfate precipitation, desalting by gel filtration, cation exchange-, hydrophobic interaction-, and reverse phase-chromatography (RP-FPLC. However, a measurable antimicrobial activity was only detected after the hydrophobic interaction and RP-FPLC steps of the purified supernatants. MALDI-TOF MS analysis of the antimicrobial fractions eluted from RP-FPLC revealed the existence of peptide fragments of lower and higher molecular mass than expected. MALDI-TOF/TOF MS analysis of selected peptides from eluted RP-FPLC samples with antimicrobial activity indicated the presence of peptide fragments not related to the amino acid sequence of the cloned bacteriocins.

  5. Pyocyanine Biosynthetic Genes in Clinical and Environmental Isolates of Pseudomonas aeruginosa and Detection of Pyocyanine’s Antimicrobial Effects with or without Colloidal Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Afrooz Rashnonejad

    2012-01-01

    Full Text Available Objective: Pyocyanine plays an important role in the pathogenesis of Pseudomonas aeruginosa, (P. aeruginosa and is known to have inhibitory and bactericidal effects. This study has aimed to detect the phenazine biosynthetic operon (phz ABCDEFG and two phenazine modifying genes (phzM and phzS by polymerase chain reaction (PCR and detection of its possible protein bands by sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE. The antimicrobial effects of pyocyanine alone and mixed with colloidal silver nanoparticles were studied.Materials and Methods: In this descriptive study, clinical and environmental species of P. aeruginosa were isolated by thioglycollate medium culture and cetrimide agar, respectively. The existence of a phenazine biosynthetic operon and two phenazine modifying genes as well as their protein products were confirmed by PCR and SDS-PAGE, respectively. Pyocyanine was extracted with chloroform and its antimicrobial effects against bacteria such as; Escherichia coli (E. coli, P. aeruginosaand Staphylococcus aureus (S. aureus bacteria and yeast Candida albicans (C. albicans were tested using well, spot and disk diffusion methods.Results: In this study, 3 out of 48 clinical strains were unable to produce pyocyanine on cetrimide and Mueller Hinton (MH agar. Two strains did not have phenazine modifying gene bands. Another strain did not have the possible protein band of the phzM gene. Pyocyanine had antimicrobial effects against the microbial strains, which increased in the presence of silver nanoparticles.Conclusion: According to the results of the present study, some P. aeruginosa strains are unable to produce pyocyanine due to the absence of the phzM or phzS genes. Therefore, these genes have an important role in pyocyanine production in P. aeruginosa. Pyocyanine shows synergistic antimicrobial effects in the presence of silver nanoparticles against microbial strains.

  6. Implication of PKS type I gene and chromatographic strategy for the biodiscovery of antimicrobial polyketide metabolites from endosymbiotic Nocardiopsis prasina CLA68

    Science.gov (United States)

    Rao, H. C. Yashavantha; Rakshith, Devaraju; Gurudatt, D. M.; Satish, Sreedharamurthy

    2016-06-01

    Advanced approach in probing for polyketide antimicrobials requires novel genomics and chromatographic strategies. An endophytic strain CLA68 was isolated from the root of Combretum latifolium Blume (Combretaceae) collected from the Western Ghats of Southern India. Strain CLA68 was then identified as Nocardiopsis prasina by its characteristic culture morphology and analysis of 16S rRNA gene sequence. Biosynthetic polyketide synthase genes were investigated using two pairs of degenerate primers. Ethyl acetate extract of CLA68 exhibited broad spectrum activity against a panel of test human pathogens. PKS type-I gene detection and chromatographic strategy yielded a robust polyketide antimicrobial compound which identified as nocapyrone E. Minimum inhibitory concentration of the purified compound against MRSA and other human pathogens ranged between 25 and 100 μg/ml. The present work highlights the utility of N. prasina CLA68 as potential source for antimicrobial polyketide nocapyrone E which could help to combat multidrug-resistant pathogens. This study demonstrates feasibility of PKS type-I gene-based molecular approach and chemical investigation by chromatographic approach is the best method for prediction and rapid discovery of novel polyketides from endosymbiotic actinomycetes. The sequence data of this endosymbiotic actinomycete is deposited in GenBank under the accession no. KP269077.

  7. Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells

    DEFF Research Database (Denmark)

    Lowry, Malcolm B; Guo, Chunxiao; Borregaard, Niels;

    2014-01-01

    Production of the human cathelicidin antimicrobial peptide gene (hCAP18/LL-37), is regulated by 1α,25-dihydroxyvitamin D3 (1,25D3) and is critical in the killing of pathogens by innate immune cells. In addition, secreted LL-37 binds extracellular receptors and modulates the recruitment and activity...... of both innate and adaptive immune cells. Evidence suggests that during infections activated immune cells locally produce increased levels of 1,25D3 thus increasing production of hCAP18/LL-37. The relative expression levels of hCAP18/LL-37 among different immune cell types are not well characterized....... The aim of this study was to determine the relative levels of hCAP18/LL-37 in human peripheral blood immune cells and determine to what extent 1,25D3 increased its expression in peripheral blood-derived cells. We show for the first time, a hierarchy of expression of hCAP18 in freshly isolated cells...

  8. Immunocytochemical detection of vasoactive intestinal peptide-like and peptide histidine isoleucine-like peptides in the nervous system and the excretory system of adult Nippostrongylus brasiliensis.

    Science.gov (United States)

    Foster, N

    1998-05-01

    Vasoactive intestinal peptide-like and peptide histidine isoleucine-like immunoreactivities were detected in the excretory duct of adult male and female Nippostrongylus brasiliensis, thus indicating the source of these two physiologically active peptides previously isolated from the excretory/secretory products of adult N. brasiliensis. In the nervous system immunoreactivity to both these peptides was confined to females and was found in the neurons of the ovijector associated ganglion. This is consistent with co-synthesis of vasoactive intestinal peptide-like and peptide histidine isoleucine-like peptides which has also been shown to occur in all mammalian vasoactive intestinal peptid-ergic neurons studied to date. However, in addition to this, and in common to some previous studies on helminth vasoactive intestinal peptide and peptide histidine isoleucine immunoreactivities, co-synthesis of the peptides was not indicated in a pair of branched neurons which projected posteriorly and peripherally from the ganglion associated with the ovijector of females and which terminated in two pairs of ganglia also exhibiting vasoactive intestinal peptide-like immunoreactivity only. The position of these ganglia indicated that they innervate muscles close to the body wall and may be responsible for the muscular contractions required for expulsion of eggs from female Nippostrongylus brasiliensis. This is also the first study to successfully detect these peptides in the excretory system of gastrointestinal nematodes.

  9. Antimicrobial Resistance and Resistance Genes in Aerobic Bacteria Isolated from Pork at Slaughter

    DEFF Research Database (Denmark)

    Li, Lili; Olsen, Rikke Heidemann; Ye, Lei

    2016-01-01

    oxytoca, Serratia marcescens, Acinetobacter baumannii, and Myroides phaeus; tet(L) in M. caseolyticus; sul1 in Vibrio cincinnatiensis; sul2 in Acinetobacter bereziniae, Acinetobacter johnsonii, and V. cincinnatiensis; and the class 1 integron and gene cassette aadA2 in V. cincinnatiensis. Approximately 6...... resistance genes were found in new carriers: bla TEM in Lactococcus garvieae, Myroides odoratimimus, Aeromonas hydrophila, Staphylococcus sciuri, Raoultella terrigena, Macrococcus caseolyticus, Acinetobacter ursingii, Sphingobacterium sp., and Oceanobacillus sp.; bla CMY-2 in Lactococcus lactis, Klebsiella...

  10. Benchmarking of methods for identification of antimicrobial resistance genes in bacterial whole genome data

    DEFF Research Database (Denmark)

    Clausen, Philip T. L. C.; Zankari, Ea; Aarestrup, Frank Møller;

    2016-01-01

    Next generation sequencing (NGS) may be an alternative to phenotypic susceptibility testing for surveillance and clinical diagnosis. However, current bioinformatics methods may be associated with false positives and negatives. In this study, a novel mapping method was developed and benchmarked...... to two different methods in current use for identification of antibiotic resistance genes in bacterial WGS data. A novel method, KmerResistance, which examines the co-occurrence of k-mers between the WGS data and a database of resistance genes, was developed. The performance of this method was compared...... with two previously described methods; ResFinder and SRST2, which use an assembly/BLAST method and BWA, respectively, using two datasets with a total of 339 isolates, covering five species, originating from the Oxford University Hospitals NHS Trust and Danish pig farms. The predicted resistance...

  11. Analysis of two lysozyme genes and antimicrobial functions of their recombinant proteins in Asian seabass.

    Directory of Open Access Journals (Sweden)

    Gui Hong Fu

    Full Text Available Lysozymes are important proteins of the innate immune system for the defense against bacterial infection. We cloned and analyzed chicken-type (c-type and goose-type (g-type lysozymes from Asian seabass (Lates calcarifer. The deduced amino acid sequence of the c-type lysozyme contained 144 residues and possessed typical structure residues, conserved catalytic residues (Glu(50 and Asp(67 and a "GSTDYGIFQINS" motif. The deduced g-type lysozyme contained 187 residues and possessed a goose egg white lysozyme (GEWL domain containing three conserved catalytic residues (Glu(71, Asp(84, Asp(95 essential for catalytic activity. Real time quantitative PCR (qRT-PCR revealed that the two lysozyme genes were constitutively expressed in all the examined tissues. The c-type lysozyme was most abundant in liver, while the g-type lysozyme was predominantly expressed in intestine and weakly expressed in muscle. The c-type and g-type transcripts were up-regulated in the kidney, spleen and liver in response to a challenge with Vibrio harveyi. The up-regulation of the c-type lysozyme was much stronger than that of the g-type lysozyme in kidney and spleen. The recombinant proteins of the c-type and g-type lysozymes showed lytic activities against the bacterial pathogens Vibrio harveyi and Photobacterium damselae in a dosage-dependent manner. We identified single nucleotide polymorphisms (SNPs in the two lysozyme genes. There were significant associations of these polymorphisms with resistance to the big belly disease. These results suggest that the c- and g-type genes play an important role in resistance to bacterial pathogens in fish. The SNP markers in the two genes associated with the resistance to bacterial pathogens may facilitate the selection of Asian seabass resistant to bacterial diseases.

  12. Comparison of antimicrobial resistance phenotypes and resistance genes in Enterococcus faecalis and Enterococcus faecium from humans in the community, broilers and pigs in Denmark

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Agersø, Yvonne; Gerner-Smidt, P.;

    2000-01-01

    Enterococcus faecalis and E. faecium isolated from humans in the community (98 and 65 isolates), broilers (126 and 122), and pigs (102 and 88) during 1998 were tested for susceptibility to 12 different antimicrobial agents and for the presence of selected genes encoding resistance using PCR...... of the 38 human fecal samples examined using selective enrichment. All vancomycin resistant isolates contained the vanA gene, all chloramphenicol resistant isolates the catpIP501 gene, and all five gentamicin resistant isolates the aac6-aph2 gene. Sixty-one (85%) of 72 erythromycin resistant E. faecalis...... examined and 57 (90%) of 63 erythromycin resistant E. faecium isolates examined contained ermB. Forty (91%) of the kanamycin resistant E. faecalis and 18 (72%) of the kanamycin resistant E. faecium isolates contained aphA3. The tet(M) gene was found in 95% of the tetracycline resistant E. faecalis and E...

  13. Virulence Genes and Antimicrobial Resistance Profiles of Pasteurella multocida Strains Isolated from Rabbits in Brazil

    Directory of Open Access Journals (Sweden)

    Thais Sebastiana Porfida Ferreira

    2012-01-01

    Full Text Available Pasteurella multocida is responsible for a wide range of diseases in domestic animals. In rabbits, the agent is related to nasal discharge, pneumonia, otitis media, pyometra, orchitis, abscess, and septicemia. One hundred and forty rabbits with respiratory diseases from four rabbitries in São Paulo State, Brazil were evaluated for the detection of P. multocida in their nasal cavities. A total of twenty-nine animals were positive to P. multocida isolation, and 46 strains were selected and characterized by means of biochemical tests and PCR. P. multocida strains were tested for capsular type, virulence genes, and resistance profile. A total of 45.6% (21/46 of isolates belonged to capsular type A, and 54.34% (25/46 of the isolates were untypeable. None of the strains harboured toxA or pfhA genes. The frequency of the other twenty genes tested was variable, and the data generated was used to build a dendrogram, showing the relatedness of strains, which were clustered according to origin. Resistance revealed to be more common against sulfonamides and cotrimoxazole, followed by erythromycin, penicillin, and amoxicillin.

  14. Antimicrobial resistance and virulence gene profiles in P. multocida strains isolated from cats.

    Science.gov (United States)

    Ferreira, Thais Sebastiana Porfida; Felizardo, Maria Roberta; de Gobbi, Debora Dirani Sena; Moreno, Marina; Moreno, Andrea Micke

    2015-03-01

    Cats are often described as carriers of Pasteurella multocida in their oral microbiota. This agent is thought to cause pneumonia, conjunctivitis, rhinitis, gingivostomatitis, abscess and osteonecrosis in cats. Human infection with P. multocida has been described in several cases affecting cat owners or after cat bites. In Brazil, the cat population is approximately 21 million animals and is increasing, but there are no studies of the presence of P. multocida in the feline population or of human cases of infection associated with cats. In this study, one hundred and ninety-one healthy cats from owners and shelters in São Paulo State, Brazil, were evaluated for the presence of P. multocida in their oral cavities. Twenty animals were positive for P. multocida , and forty-one strains were selected and characterized by means of biochemical tests and PCR. The P. multocida strains were tested for capsular type, virulence genes and resistance profile. A total of 75.6% (31/41) of isolates belonged to capsular type A, and 24.4% (10/41) of the isolates were untypeable. None of the strains harboured toxA, tbpA or pfhA genes. The frequencies of the other genes tested were variable, and the data generated were used to build a dendrogram showing the relatedness of strains, which were clustered according to origin. The most common resistance profile observed was against sulfizoxazole and trimethoprim-sulphamethoxazole.

  15. Antimicrobial resistance and virulence gene profiles in P. multocida strains isolated from cats

    Directory of Open Access Journals (Sweden)

    Thais Sebastiana Porfida Ferreira

    2015-03-01

    Full Text Available Cats are often described as carriers of Pasteurella multocida in their oral microbiota. This agent is thought to cause pneumonia, conjunctivitis, rhinitis, gingivostomatitis, abscess and osteonecrosis in cats. Human infection with P. multocida has been described in several cases affecting cat owners or after cat bites. In Brazil, the cat population is approximately 21 million animals and is increasing, but there are no studies of the presence of P. multocida in the feline population or of human cases of infection associated with cats. In this study, one hundred and ninety-one healthy cats from owners and shelters in São Paulo State, Brazil, were evaluated for the presence of P. multocida in their oral cavities. Twenty animals were positive for P. multocida, and forty-one strains were selected and characterized by means of biochemical tests and PCR. The P. multocida strains were tested for capsular type, virulence genes and resistance profile. A total of 75.6% (31/41 of isolates belonged to capsular type A, and 24.4% (10/41 of the isolates were untypeable. None of the strains harboured toxA, tbpA or pfhA genes. The frequencies of the other genes tested were variable, and the data generated were used to build a dendrogram showing the relatedness of strains, which were clustered according to origin. The most common resistance profile observed was against sulfizoxazole and trimethoprim-sulphamethoxazole.

  16. Dissemination of antimicrobial resistance in microbial ecosystems through horizontal gene transfer

    Directory of Open Access Journals (Sweden)

    Christian Johannes Hendrik Von Wintersdorff

    2016-02-01

    Full Text Available The emergence and spread of antibiotic resistance among pathogenic bacteria has been a rising problem for public health in recent decades. It is becoming increasingly recognized that not only antibiotic resistance genes (ARGs encountered in clinical pathogens are of relevance, but rather, all pathogenic, commensal as well as environmental bacteria – and also mobile genetic elements and bacteriophages – form a reservoir of ARGs (the resistome from which pathogenic bacteria can acquire resistance via horizontal gene transfer (HGT. HGT has caused antibiotic resistance to spread from commensal and environmental species to pathogenic ones, as has been shown for some clinically important ARGs. Of the three canonical mechanisms of HGT, conjugation is thought to have the greatest influence on the dissemination of ARGs. While transformation and transduction are deemed less important, recent discoveries suggest their role may be larger than previously thought. Understanding the extent of the resistome and how its mobilization to pathogenic bacteria takes place is essential for efforts to control the dissemination of these genes. Here, we will discuss the concept of the resistome, provide examples of HGT of clinically relevant ARGs and present an overview of the current knowledge of the contributions the various HGT mechanisms make to the spread of antibiotic resistance.

  17. Uropathogenic Escherichia coli (UPEC) induced antimicrobial gene expression in the male reproductive tract of rat: evaluation of the potential of Defensin 21 to limit infection.

    Science.gov (United States)

    Biswas, B; Bhushan, S; Rajesh, A; Suraj, S K; Lu, Y; Meinhardt, A; Yenugu, S

    2015-03-01

    Escherichia coli (E. coli) is a common pathogen in epididymitis, which represents a prevalent entity in male reproductive tract infections (RTI). Although current treatment regimens using antibiotics are satisfactory, development of antimicrobial resistance by the pathogen represents a challenge in the management of RTI. Hence, identification of antimicrobial peptides as alternatives to antibiotics has gained importance. We demonstrate that in a rat epididymo-orchitis model induced with uropathogenic E. coli (UPEC) strain MTCC 729, the expression of defensins and defensin-like Spag11 genes are induced in the epididymis and testes. The induction of antimicrobial gene expression is paralleled by phosphorylation of the NF-kB subunit p65 and the inhibitor of NFkB (IkB-alpha), decreased levels of histone deacetylase 1 and increased methylation of Histone 3, indicating the role of classical Toll-like receptor mediated signaling and epigenetic regulation. Recombinant Defensin 21, when administered to UPEC-infected rats, substantially reduced the bacterial load in the epididymis and testis and proved to be more effective than gentamycin. The ability of Defensin 21 to limit RTI provides support that antibacterial proteins of the male reproductive tract may be used as potential alternatives to antibiotics in treatment of this disease.

  18. Detection of tetracycline resistance determinant tetA gene and antimicrobial resistance pattern in Escherichia coli isolates recovered from healthy layer chickens

    Directory of Open Access Journals (Sweden)

    A. Balasubramaniam

    2014-09-01

    Full Text Available Aim: The aim was to study the occurrence of tetracycline resistance determinant tetA gene, and antibacterial resistance pattern in commensal Escherichia coli recovered from healthy non-clinical layer chickens. Materials and Methods: Twenty-four cloacal swabs were obtained from 15 flocks in five different layer farms located at around Namakkal, which is a place of high-intensity layer chicken rearing in south India. Identification of E. coli was carried out by performing cultural and biochemical tests. Antimicrobial resistance test was carried out using disc diffusion method. The polymerase chain reaction employing tetAC forward and tetAC reverse primers were carried out to detect tetA gene conferring resistance to tetracycline. Result: All the collected cloacal swabs yielded E. coli. Twenty-one isolates (88% were resistant to tetracycline antibiotic in disc diffusion method. All the isolates showed resistance to more than six antibiotics, which implied existence of multidrug resistant microbiota in intestine of poultry. Only seven (29% isolates showed the presence of tetA gene indicating the involvement of either other one or more efflux gene(s, namely tetB, tetC and tetD or ribosomal protection encoded by tetM, tetO, tetQ and tetS genes than tetA gene. Conclusion: Based on the presence of tetA gene among tetracycline-resistant bacteria in healthy non-clinical food-producing animals such as layer chickens, it can be significant in human medicine as tetA gene could easily be spread to other bacteria. This kind of phenomenon can be extrapolated in transfer of resistance for other antibacterial essential for treating bacterial infections in human. We conclude that preventing the spread of antimicrobial resistance through direct or indirect contact, consumed food/feed and through the environment is empirical in reduction of failures while treating bacterial infections.

  19. Antimicrobial Pesticides

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Pesticides Share Facebook Twitter Google+ ... of antimicrobial pesticides (Part 158W) Antimicrobials play an important role in public health and safety. While providing ...

  20. Antimicrobial susceptibility and macrolide resistance genes in Streptococcus pyogenes collected in Austria and Hungary.

    Science.gov (United States)

    Gattringer, Rainer; Sauermann, Robert; Lagler, Heimo; Stich, Karin; Buxbaum, Astrid; Graninger, Wolfgang; Georgopoulos, Apostolos

    2004-09-01

    A total of 341 clinical isolates of Streptococcus pyogenes from Vienna, Austria and three Hungarian cities were tested for susceptibility to four macrolides and 12 other antibiotics. All isolates were fully susceptible to penicillin and the other beta-lactams tested. A high level of tetracycline resistance was found in Austria (26.7%) and in Hungary (30.5%). The rate of resistance to erythromycin, clarithromycin and azithromycin was 4.7% in Vienna and 3.7% in the Hungarian communities. In both countries, the MIC(90) values of erythromycin and clarithromycin were 0.12 mg/L and the MIC(90) of josamycin was 0.5mg/L. The M phenotype of resistance conferred by the mefA genes was predominant (n = 9) among the macrolide-resistant isolates (n = 14).

  1. Deletion of gene encoding methyltransferase (gidB) confers high-level antimicrobial resistance in Salmonella.

    Science.gov (United States)

    Mikheil, Dareen M; Shippy, Daniel C; Eakley, Nicholas M; Okwumabua, Ogi E; Fadl, Amin A

    2012-04-01

    The glucose-inhibited division gene (gid)B, which resides in the gid operon, was thought to have a role in the modulation of genes similar to that of gidA. Recent studies have indicated that GidB is a methyltransferase enzyme that is involved in the methylation of the 16S ribosomal RNA (rRNA) in Escherichia coli. In this study, we investigated the role of GidB in susceptibility to antibiotics and the overall biology of Salmonella. A gidB isogenic mutant of Salmonella was constructed and subsequently characterized under different conditions. Our data indicated that growth and invasion characteristics of the gidB mutant were similar to those of the wild type (WT). The gidB mutant was outgrown by the WT in a competitive growth assay, indicating a compromised overall bacterial fitness. Under the stress of nalidixic acid, the gidB mutant's motility was significantly reduced. Similarly, the mutant showed a filamentous morphology and smaller colony size compared with the rod-shaped and large colonies of the WT in the presence of nalidixic acid. Most importantly, deletion of gidB conferred high-level resistance to the aminoglycoside antibiotics streptomycin and neomycin. A primer extension assay determined the methylation site for the WT to be at G527 of the 16S rRNA. A lack of methylation in the mutant indicated that GidB is required for this methylation. Taken together, these data indicate that the GidB enzyme has a significant role in the alteration of antibiotic susceptibility and the modulation of growth and morphology under stress conditions in Salmonella.

  2. Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells.

    Science.gov (United States)

    Lowry, Malcolm B; Guo, Chunxiao; Borregaard, Niels; Gombart, Adrian F

    2014-09-01

    Production of the human cathelicidin antimicrobial peptide gene (hCAP18/LL-37), is regulated by 1α,25-dihydroxyvitamin D3 (1,25D3) and is critical in the killing of pathogens by innate immune cells. In addition, secreted LL-37 binds extracellular receptors and modulates the recruitment and activity of both innate and adaptive immune cells. Evidence suggests that during infections activated immune cells locally produce increased levels of 1,25D3 thus increasing production of hCAP18/LL-37. The relative expression levels of hCAP18/LL-37 among different immune cell types are not well characterized. The aim of this study was to determine the relative levels of hCAP18/LL-37 in human peripheral blood immune cells and determine to what extent 1,25D3 increased its expression in peripheral blood-derived cells. We show for the first time, a hierarchy of expression of hCAP18 in freshly isolated cells with low levels in lymphocytes, intermediate levels in monocytes and the highest levels found in neutrophils. In peripheral blood-derived cells, the highest levels of hCAP18 following treatment with 1,25D3 were in macrophages, while comparatively lower levels were found in GM-CSF-derived dendritic cells and osteoclasts. We also tested whether treatment with parathyroid hormone in combination with 1,25D3 would enhance hCAP18 induction as has been reported in skin cells, but we did not find enhancement in any immune cells tested. Our results indicate that hCAP18 is expressed at different levels according to cell type and lineage. Furthermore, potent induction of hCAP18 by 1,25D3 in macrophages and dendritic cells may modulate functions of both innate and adaptive immune cells at sites of infection.

  3. Shigella in Brazilian children with acute diarrhoea: prevalence, antimicrobial resistance and virulence genes.

    Science.gov (United States)

    Sousa, Mireille Ângela Bernardes; Mendes, Edilberto Nogueira; Collares, Guilherme Birchal; Péret-Filho, Luciano Amedée; Penna, Francisco José; Magalhães, Paula Prazeres

    2013-02-01

    Diarrhoeal disease is still considered a major cause of morbidity and mortality among children. Among diarrhoeagenic agents, Shigella should be highlighted due to its prevalence and the severity of the associated disease. Here, we assessed Shigella prevalence, drug susceptibility and virulence factors. Faeces from 157 children with diarrhoea who sought treatment at the Children's Hospital João Paulo II, a reference children´s hospital in Belo Horizonte, state of Minas Gerais, Brazil, were cultured and drug susceptibility of the Shigella isolates was determined by the disk diffusion technique. Shigella virulence markers were identified by polymerase chain reaction. The bacterium was recovered from 10.8% of the children (88.2% Shigella sonnei). The ipaH, iuc, sen and ial genes were detected in strains isolated from all shigellosis patients; set1A was only detected in Shigella flexneri. Additionally, patients were infected by Shigella strains of different ial, sat, sen and set1A genotypes. Compared to previous studies, we observed a marked shift in the distribution of species from S. flexneri to S. sonnei and high rates of trimethoprim/sulfamethoxazole resistance.

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

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    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.

  5. Antimicrobial resistance and virulence factor gene profiles of Enterococcus spp. isolates from wild Arctocephalus australis (South American fur seal) and Arctocephalus tropicalis (Subantarctic fur seal).

    Science.gov (United States)

    Santestevan, Naiara Aguiar; de Angelis Zvoboda, Dejoara; Prichula, Janira; Pereira, Rebeca Inhoque; Wachholz, Guilherme Raffo; Cardoso, Leonardo Almansa; de Moura, Tiane Martin; Medeiros, Aline Weber; de Amorin, Derek Blaese; Tavares, Maurício; d'Azevedo, Pedro Alves; Franco, Ana Claudia; Frazzon, Jeverson; Frazzon, Ana Paula Guedes

    2015-12-01

    Enterococci are natural inhabitants of the gastrointestinal tracts in humans and animals. Epidemiological data suggest that enterococci are important reservoirs of antimicrobial resistant genes that may be transmitted from other bacterial species The aim of this study was to investigate the species composition, antimicrobial resistance and virulence genes in enterococci recovered from fecal samples of wild Arctocephalus australis and A. tropicalis found dead along the South Coast of Brazil. From a total of 43 wild fur seals, eleven were selected for this study. Phenotypic and genotypic characterizations were used to classify Enterococcus species. Strains were tested for susceptibility to 10 antibiotics, presence of ace, gelE, asa, cylA, tet(L), tet(M) and erm(B) genes by PCR, and genetic variability using RAPD-PCR. Among the 50 enterococci isolated, 40% were Enterococcus faecalis, 40% E. hirae, 12% E. casseliflavus and 8 % other enterococcal species. Resistance profiles were observed to erythromycin, nitrofurantoin, tetracycline, norfloxacin and ciprofloxacin. The prevalence of virulence genes was ace (68%), gelE (54%), asa (22%) and cylA (4%). In erythromycin- and tetracycline strains, erm(B) and tet(M) were detected, respectively. The RAPD-PCR demonstrated a close phylogenetic relationship between the enterococci isolated from A. australis and A. tropicalis. In conclusion, different enterococcus species showing antimicrobial resistance and virulence determinates were isolated from fecal samples of fur seals. Antibiotic resistant strains in these animals could be related within food chain and aquatic pollutants or linked to environmental resistome, and demonstrates the potential importance of these animals as reservoirs and disseminators of such determinants in marine environmental.

  6. Pharmacogenomics of antimicrobial agents.

    Science.gov (United States)

    Aung, Ar Kar; Haas, David W; Hulgan, Todd; Phillips, Elizabeth J

    2014-01-01

    Antimicrobial efficacy and toxicity varies between individuals owing to multiple factors. Genetic variants that affect drug-metabolizing enzymes may influence antimicrobial pharmacokinetics and pharmacodynamics, thereby determining efficacy and/or toxicity. In addition, many severe immune-mediated reactions have been associated with HLA class I and class II genes. In the last two decades, understanding of pharmacogenomic factors that influence antimicrobial efficacy and toxicity has rapidly evolved, leading to translational success such as the routine use of HLA-B*57:01 screening to prevent abacavir hypersensitivity reactions. This article examines recent advances in the field of antimicrobial pharmacogenomics that potentially affect treatment efficacy and toxicity, and challenges that exist between pharmacogenomic discovery and translation into clinical use.

  7. Antimicrobial stewardship.

    Science.gov (United States)

    Allerberger, F; Mittermayer, H

    2008-03-01

    The aim of antimicrobial management or stewardship programmes is to ensure proper use of antimicrobial agents in order to provide the best treatment outcomes, to lessen the risk of adverse effects (including antimicrobial resistance), and to promote cost-effectiveness. Increasingly, long-term sustainability is found to be the major focus of antimicrobial stewardship. Implementing structural measures in healthcare institutions is therefore a major, but not the sole, focus of attention in promoting prudent use of antibiotics. The problem of antimicrobial resistance requires common strategies at all levels--for the prescribers and at ward, departmental, hospital, national and international levels.

  8. Comparison of two DNA microarrays for detection of plasmid-mediated antimicrobial resistance and virulence factor genes in clinical isolates of Enterobacteriaceae and non-Enterobacteriaceae.

    LENUS (Irish Health Repository)

    Walsh, Fiona

    2010-06-01

    A DNA microarray was developed to detect plasmid-mediated antimicrobial resistance (AR) and virulence factor (VF) genes in clinical isolates of Enterobacteriaceae and non-Enterobacteriaceae. The array was validated with the following bacterial species: Escherichiacoli (n=17); Klebsiellapneumoniae (n=3); Enterobacter spp. (n=6); Acinetobacter genospecies 3 (n=1); Acinetobacterbaumannii (n=1); Pseudomonasaeruginosa (n=2); and Stenotrophomonasmaltophilia (n=2). The AR gene profiles of these isolates were identified by polymerase chain reaction (PCR). The DNA microarray consisted of 155 and 133 AR and VF gene probes, respectively. Results were compared with the commercially available Identibac AMR-ve Array Tube. Hybridisation results indicated that there was excellent correlation between PCR and array results for AR and VF genes. Genes conferring resistance to each antibiotic class were identified by the DNA array. Unusual resistance genes were also identified, such as bla(SHV-5) in a bla(OXA-23)-positive carbapenem-resistant A. baumannii. The phylogenetic group of each E. coli isolate was verified by the array. These data demonstrate that it is possible to screen simultaneously for all important classes of mobile AR and VF genes in Enterobacteriaceae and non-Enterobacteriaceae whilst also assigning a correct phylogenetic group to E. coli isolates. Therefore, it is feasible to test clinical Gram-negative bacteria for all known AR genes and to provide important information regarding pathogenicity simultaneously.

  9. The presence of sboA and spaS genes and antimicrobial peptides subtilosin A and subtilin among Bacillus strains of the Amazon basin.

    Science.gov (United States)

    Velho, Renata Voltolini; Basso, Ana Paula; Segalin, Jeferson; Costa-Medina, Luis Fernando; Brandelli, Adriano

    2013-03-01

    This report demonstrates the usefulness of PCR for the genes spaS and sboA as a means of identifying Bacillus strains with a potential to produce subtilin and subtilosin A. One collection strain and five Bacillus spp. isolated from aquatic environments in the Amazon basin were screened by PCR using primers for sboA and spaS designed specifically for this study. The sequences of the PCR products showed elevated homology with previously described spaS and sboA genes. Antimicrobial peptides were isolated from culture supernatants and analyzed by mass spectrometry. For all samples, the mass spectra revealed clusters with peaks at m/z 3300-3500 Da, corresponding to subtilosin A, subtilin and isoforms of these peptides. These results suggest that the antimicrobial activity of these strains may be associated with the production of subtilosin A and/or subtilin. The PCR used here was efficient in identifying novel Bacillus strains with the essential genes for producing subtilosin A and subtilin.

  10. The presence of sboA and spaS genes and antimicrobial peptides subtilosin A and subtilin among Bacillus strains of the Amazon basin

    Science.gov (United States)

    Velho, Renata Voltolini; Basso, Ana Paula; Segalin, Jeferson; Costa-Medina, Luis Fernando; Brandelli, Adriano

    2013-01-01

    This report demonstrates the usefulness of PCR for the genes spaS and sboA as a means of identifying Bacillus strains with a potential to produce subtilin and subtilosin A. One collection strain and five Bacillus spp. isolated from aquatic environments in the Amazon basin were screened by PCR using primers for sboA and spaS designed specifically for this study. The sequences of the PCR products showed elevated homology with previously described spaS and sboA genes. Antimicrobial peptides were isolated from culture supernatants and analyzed by mass spectrometry. For all samples, the mass spectra revealed clusters with peaks at m/z 3300–3500 Da, corresponding to subtilosin A, subtilin and isoforms of these peptides. These results suggest that the antimicrobial activity of these strains may be associated with the production of subtilosin A and/or subtilin. The PCR used here was efficient in identifying novel Bacillus strains with the essential genes for producing subtilosin A and subtilin. PMID:23569414

  11. Relationships between antimicrobial resistance, distribution of virulence factor genes and the origin of Trueperella pyogenes isolated from domestic animals and European bison (Bison bonasus).

    Science.gov (United States)

    Rzewuska, Magdalena; Czopowicz, Michał; Gawryś, Marta; Markowska-Daniel, Iwona; Bielecki, Wojciech

    2016-07-01

    Trueperella pyogenes is an opportunistic pathogen causing suppurative infections in livestock and wild animals. Although this bacterium is known for a long time, our knowledge about its pathogenicity is still insufficient. In this study the relationships between antimicrobial resistance profiles, distribution of virulence factor genes and the origin of T. pyogenes isolates were investigated. Isolates (n = 97) from various infections in domestic animals and European bison were studied. Minimal inhibitory concentrations of 12 antimicrobials were determined by a strip diffusion method, and PCR was used for detection of genes encoding seven putative virulence factors. All strains were susceptible to tested beta-lactams, and a statistically significant correlation between the resistance to enrofloxacin, tetracycline, macrolides, clindamycin, and a strain origin was found. The isolates from European bison were more susceptible than those from livestock, however the resistance to tetracycline and fluoroquinolones was observed. The plo and fimA genes were detected in all strains. There was no statistically significant association between the distribution of particular virulence factor genes and the type of infection, but the nanH, nanP and fimG genes were less frequently found in the isolates from European bison. The presence of three genes, nanP, nanH and cbpA, was found to be related to the resistance to tetracycline and ciprofloxacin. In conclusion, the resistance patterns of T. pyogenes were correlated with an isolate origin, but our findings did not allow to indicate which of the putative virulence factors may play a crucial role in the pathogenesis of particular types of T. pyogenes infection.

  12. Identification of Legionella pneumophila rcp, a pagP-like gene that confers resistance to cationic antimicrobial peptides and promotes intracellular infection.

    Science.gov (United States)

    Robey, M; O'Connell, W; Cianciotto, N P

    2001-07-01

    In the course of characterizing a locus involved in heme utilization, we identified a Legionella pneumophila gene predicted to encode a protein with homology to the product of the Salmonella enterica serovar Typhimurium pagP gene. In Salmonella, pagP increases resistance to the bactericidal effects of cationic antimicrobial peptides (CAMPs). Mutants with insertions in the L. pneumophila pagP-like gene were generated and showed decreased resistance to different structural classes of CAMPs compared to the wild type; hence, this gene was designated rcp for resistance to cationic antimicrobial peptides. Furthermore, Legionella CAMP resistance was induced by growth in low-magnesium medium. To determine whether rcp had any role in intracellular survival, mutants were tested in the two most relevant host cells for Legionnaires' disease, i.e., amoebae and macrophages. These mutants exhibited a 1,000-fold-decreased recovery during a Hartmannella vermiformis coculture. Complementation of the infectivity defect could be achieved by introduction of a plasmid containing the intact rcp gene. Mutations in rcp consistently reduced both the numbers of bacteria recovered during intracellular infection and their cytopathic capacity for U937 macrophages. The rcp mutant was also more defective for lung colonization of A/J mice. Growth of rcp mutants in buffered yeast extract broth was identical to that of the wild type, indicating that the observed differences in numbers of bacteria recovered from host cells were not due to a generalized growth defect. However, in low-Mg(2+) medium, the rcp mutant was impaired in stationary-phase survival. This is the first demonstration of a pagP-like gene, involved in resistance to CAMPs, being required for intracellular infection and virulence.

  13. RNAi knock-down of shrimp Litopenaeus vannamei Toll gene and immune deficiency gene reveals their difference in regulating antimicrobial peptides transcription.

    Science.gov (United States)

    Hou, Fujun; He, Shulin; Liu, Yongjie; Zhu, Xiaowen; Sun, Chengbo; Liu, Xiaolin

    2014-06-01

    NF-κB dependent antimicrobial peptides (AMPs) are of critical importance in protecting insects or mammals from microorganisms infection. However, we still do not make clear signaling pathways in regulating AMPs expression in shrimps. In this study, RNAi approach was used to study differences between Toll signaling pathway and immune deficiency signaling pathway in regulating the transcription of NF-κB dependent AMPs post bacteria challenge. Results showed that the transcription level of anti-lipopolysaccharide factor was highly suppressed in Litopenaeus vannamei immune deficiency (LvIMD) silenced shrimps by gene specific dsRNA compared to Litopenaeus vannamei Toll (LvToll) silenced shrimps with or without Vibrio anguillarum and Micrococcus lysodeikticus challenge. Conversely the transcription level of penaeidin3a was significantly suppressed in LvToll silenced shrimps compared to LvIMD silenced shrimps. However, no obvious difference was found in regulating the transcription of CrustinP. Meanwhile, we found that silencing LvToll both down regulated the transcription of Dorsal and Relish while silencing LvIMD only down regulated the transcription of Relish. At last, shrimp survival experiment showed that post V. anguillarum challenge high mortality was found both in LvToll and LvIMD silenced groups while post M. lysodeikticus challenge we saw high mortality only in LvToll silenced group. Hence, we conclude that shrimp L. vannamei Toll pathway and IMD pathway might be different in regulating the transcription of NF-κB dependent AMPs and responding to bacteria challenge but not independent of each other.

  14. Antimicrobial Activity.

    Science.gov (United States)

    2016-01-01

    Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter.

  15. Detecção de genes toxigênicos, susceptibilidade antimicrobiana e antagonismo in vitro de Staphylococcus spp. isolados de queijos artesanais | Evaluation of toxicity genes, antimicrobial susceptibility, and in vitro antagonism of Staphylococcus spp. isolated from artisanal cheese

    Directory of Open Access Journals (Sweden)

    Dalila Lapinha Silva Oliveira Rosa

    2015-02-01

    Full Text Available Cepas de Staphylococcus spp. molecularmente identificadas foram submetidas à Reação em Cadeia da Polimerase (PCR, utilizando-se iniciadores específicos para a detecção de genes codificadores de enterotoxinas clássicas (SEA, SEB, SEC, SED, SEE e da Toxina-1 da Síndrome do Choque Tóxico (TSST-1. Foi realizada PCR-Multiplex para detecção dos genes sea, sec, sed e see. Para seb e tst, foram realizadas PCR-Uniplex. Além disso, foi analisado o perfil de susceptibilidade das cepas a antimicrobianos de diferentes classes e foi verificado antagonismo in vitro entre Lactobacillus spp. e as cepas estudadas. Genes codificadores de enteroxinas clássicas, assim como de TSST-1, não foram encontrados. Em relação ao antibiograma, Sulfonamida, Penicilina, Ceftazidima e Oxacilina apresentaram os maiores percentuais de resistência (100, 80, 60 e 40%, respectivamente. Os demais antimicrobianos foram eficientes em percentuais acima de 70%. Lactobacillus spp. foram capazes de inibir o desenvolvimento in vitro de Staphylococcus spp. Conclui-se que as cepas estudadas não possuem genes codificadores da produção de enterotoxinas clássicas e TSST-1, são sensíveis à maioria dos antimicrobianos e são inibidos por bactérias do gênero Lactobacillus. --------------------------------------------------------------------------------------------- Staphylococcus spp. isolated from samples of Minas cheese traditionally manufactured following artisan procedures were identified using molecular techniques and further analyzed using PCR and specific primers for the detection of classic enterotoxins (SEA, SEB, SEC, SED, and SEE and toxic shock syndrome toxin-1 (TSST-1. Specific sea, sec, sed, and see genes were identified using multiplex PCR, whereas seb and tst genes were detected by uniplex PCR. In vitro antagonism with Lactobacillus spp. was evaluated to assess antimicrobial susceptibility. Classic enterotoxins and TSST-1 genes were not detected. The

  16. Genetic diversity, virulence genes and antimicrobial resistance of Salmonella Enteritidis isolated from food and humans over a 24-year period in Brazil.

    Science.gov (United States)

    Campioni, Fábio; Moratto Bergamini, Alzira Maria; Falcão, Juliana P

    2012-12-01

    Salmonellosis is a major health problem worldwide. Serovar Enteritidis has been a primary cause of Salmonella outbreaks in many countries. In Brazil, few molecular typing studies have been performed. The aims of this study were to molecularly type Salmonella Enteritidis strains isolated in Brazil in order to determine the genetic relationship between strains of food and human origin, as well as, to assess their pathogenic potential and antimicrobial resistance. A total of 128 S. Enteritidis strains isolated from human feces (67) and food (61) between 1986 and 2010 were studied. The genotypic diversity was assessed by ERIC-PCR and PFGE using XbaI, the antimicrobial resistance by the disc-diffusion assay and the presence of the SPI-1, SPI-2 and pSTV virulence genes assessed by PCR. The ERIC-PCR results revealed that 112 strains exhibited a similarity of >85.4% and the PFGE that 96 strains exhibited a similarity of >80.0%. Almost all strains (97.6%) harbored all 13 virulence genes investigated. Thirty-six strains (28.12%) were resistant to nalidixic acid. In conclusion, the nalidixic acid resistance observed after 1996 is indicative of an increase in the use of this drug. It may be suggested that these 128 strains might have descended from a common ancestor that differed little over 24 years and has been both contaminating food and humans and causing disease for more than two decades in Brazil.

  17. Bacillus subtilis from Soybean Food Shows Antimicrobial Activity for Multidrug-Resistant Acinetobacter baumannii by Affecting the adeS Gene.

    Science.gov (United States)

    Wang, Tieshan; Su, Jianrong

    2016-12-28

    Exploring novel antibiotics is necessary for multidrug-resistant pathogenic bacteria. Because the probiotics in soybean food have antimicrobial activities, we investigated their effects on multidrug-resistant Acinetobacter baumannii. Nineteen multidrug-resistant A. baumannii strains were clinifcally isolated as an experimental group and 11 multidrug-sensitive strains as controls. The growth rates of all bacteria were determined by using the analysis for xCELLigence Real-Time Cell. The combination of antibiotics showed synergistic effects on the strains in the control group but no effect on the strains in the experimental group. Efflux pump gene adeS was absent in all the strains from the control group, whereas it exists in all the strains from the experimental group. Furthermore, all the strains lost multidrug resistance when an adeS inhibitor was used. One strain of probiotics isolated from soybean food showed high antimicrobial activity for multidrug-resistant A. baumannii. The isolated strain belongs to Bacillus subtilis according to 16S RNA analysis. Furthermore, E. coli showed multidrug resistance when it was transformed with the adeS gene from A. baumannii whereas the resistant bacteria could be inhibited completely by isolated Bacillus subtilis. Thus, probiotics from soybean food provide potential antibiotics against multidrug-resistant pathogenic bacteria.

  18. Comparative Genotypes, Staphylococcal Cassette Chromosome mec (SCCmec Genes and Antimicrobial Resistance amongst Staphylococcus epidermidis and Staphylococcus haemolyticus Isolates from Infections in Humans and Companion Animals.

    Directory of Open Access Journals (Sweden)

    Brenda A McManus

    Full Text Available This study compares the characteristics of Staphylococcus epidermidis (SE and Staphylococcus haemolyticus (SH isolates from epidemiologically unrelated infections in humans (Hu (28 SE-Hu; 8 SH-Hu and companion animals (CpA (12 SE-CpA; 13 SH-CpA. All isolates underwent antimicrobial susceptibility testing, multilocus sequence typing and DNA microarray profiling to detect antimicrobial resistance and SCCmec-associated genes. All methicillin-resistant (MR isolates (33/40 SE, 20/21 SH underwent dru and mecA allele typing. Isolates were predominantly assigned to sequence types (STs within a single clonal complex (CC2, SE, 84.8%; CC1, SH, 95.2%. SCCmec IV predominated among MRSE with ST2-MRSE-IVc common to both Hu (40.9% and CpA (54.5%. Identical mecA alleles and nontypeable dru types (dts were identified in one ST2-MRSE-IVc Hu and CpA isolate, however, all mecA alleles and 2/4 dts detected among 18 ST2-MRSE-IVc isolates were closely related, sharing >96.5% DNA sequence homology. Although only one ST-SCCmec type combination (ST1 with a non-typeable [NT] SCCmec NT9 [class C mec and ccrB4] was common to four MRSH-Hu and one MRSH-CpA, all MRSH isolates were closely related based on similar STs, SCCmec genes (V/VT or components thereof, mecA alleles and dts. Overall, 39.6% of MR isolates harbored NT SCCmec elements, and ACME was more common amongst MRSE and CpA isolates. Multidrug resistance (MDR was detected among 96.7% of isolates but they differed in the prevalence of specific macrolide, aminoglycoside and trimethoprim resistance genes amongst SE and SH isolates. Ciprofloxacin, rifampicin, chloramphenicol [fexA, cat-pC221], tetracycline [tet(K], aminoglycosides [aadD, aphA3] and fusidic acid [fusB] resistance was significantly more common amongst CpA isolates. SE and SH isolates causing infections in Hu and CpA hosts belong predominantly to STs within a single lineage, harboring similar but variable SCCmec genes, mecA alleles and dts. Host and

  19. Screening for Genes Coding for Putative Antitumor Compounds, Antimicrobial and Enzymatic Activities from Haloalkalitolerant and Haloalkaliphilic Bacteria Strains of Algerian Sahara Soils

    Directory of Open Access Journals (Sweden)

    Okba Selama

    2014-01-01

    Full Text Available Extreme environments may often contain unusual bacterial groups whose physiology is distinct from those of normal environments. To satisfy the need for new bioactive pharmaceuticals compounds and enzymes, we report here the isolation of novel bacteria from an extreme environment. Thirteen selected haloalkalitolerant and haloalkaliphilic bacteria were isolated from Algerian Sahara Desert soils. These isolates were screened for the presence of genes coding for putative antitumor compounds using PCR based methods. Enzymatic, antibacterial, and antifungal activities were determined by using cultural dependant methods. Several of these isolates are typical of desert and alkaline saline soils, but, in addition, we report for the first time the presence of a potential new member of the genus Nocardia with particular activity against the yeast Saccharomyces cerevisiae. In addition to their haloalkali character, the presence of genes coding for putative antitumor compounds, combined with the antimicrobial activity against a broad range of indicator strains and their enzymatic potential, makes them suitable for biotechnology applications.

  20. Screening for genes coding for putative antitumor compounds, antimicrobial and enzymatic activities from haloalkalitolerant and haloalkaliphilic bacteria strains of Algerian Sahara Soils.

    Science.gov (United States)

    Selama, Okba; Amos, Gregory C A; Djenane, Zahia; Borsetto, Chiara; Laidi, Rabah Forar; Porter, David; Nateche, Farida; Wellington, Elizabeth M H; Hacène, Hocine

    2014-01-01

    Extreme environments may often contain unusual bacterial groups whose physiology is distinct from those of normal environments. To satisfy the need for new bioactive pharmaceuticals compounds and enzymes, we report here the isolation of novel bacteria from an extreme environment. Thirteen selected haloalkalitolerant and haloalkaliphilic bacteria were isolated from Algerian Sahara Desert soils. These isolates were screened for the presence of genes coding for putative antitumor compounds using PCR based methods. Enzymatic, antibacterial, and antifungal activities were determined by using cultural dependant methods. Several of these isolates are typical of desert and alkaline saline soils, but, in addition, we report for the first time the presence of a potential new member of the genus Nocardia with particular activity against the yeast Saccharomyces cerevisiae. In addition to their haloalkali character, the presence of genes coding for putative antitumor compounds, combined with the antimicrobial activity against a broad range of indicator strains and their enzymatic potential, makes them suitable for biotechnology applications.

  1. Application of microarray and functional-based screening methods for the detection of antimicrobial resistance genes in the microbiomes of healthy humans.

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    Roderick M Card

    Full Text Available The aim of this study was to screen for the presence of antimicrobial resistance genes within the saliva and faecal microbiomes of healthy adult human volunteers from five European countries. Two non-culture based approaches were employed to obviate potential bias associated with difficult to culture members of the microbiota. In a gene target-based approach, a microarray was employed to screen for the presence of over 70 clinically important resistance genes in the saliva and faecal microbiomes. A total of 14 different resistance genes were detected encoding resistances to six antibiotic classes (aminoglycosides, β-lactams, macrolides, sulphonamides, tetracyclines and trimethoprim. The most commonly detected genes were erm(B, blaTEM, and sul2. In a functional-based approach, DNA prepared from pooled saliva samples was cloned into Escherichia coli and screened for expression of resistance to ampicillin or sulphonamide, two of the most common resistances found by array. The functional ampicillin resistance screen recovered genes encoding components of a predicted AcrRAB efflux pump. In the functional sulphonamide resistance screen, folP genes were recovered encoding mutant dihydropteroate synthase, the target of sulphonamide action. The genes recovered from the functional screens were from the chromosomes of commensal species that are opportunistically pathogenic and capable of exchanging DNA with related pathogenic species. Genes identified by microarray were not recovered in the activity-based screen, indicating that these two methods can be complementary in facilitating the identification of a range of resistance mechanisms present within the human microbiome. It also provides further evidence of the diverse reservoir of resistance mechanisms present in bacterial populations in the human gut and saliva. In future the methods described in this study can be used to monitor changes in the resistome in response to antibiotic therapy.

  2. Analysis of expressed sequence tags (ESTs) from avocado seed (Persea americana var. drymifolia) reveals abundant expression of the gene encoding the antimicrobial peptide snakin.

    Science.gov (United States)

    Guzmán-Rodríguez, Jaquelina J; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis; Ochoa-Zarzosa, Alejandra; Suárez-Rodríguez, Luis María; Rodríguez-Zapata, Luis C; Salgado-Garciglia, Rafael; Jimenez-Moraila, Beatriz; López-Meza, Joel E; López-Gómez, Rodolfo

    2013-09-01

    Avocado is one of the most important fruits in the world. Avocado "native mexicano" (Persea americana var. drymifolia) seeds are widely used in the propagation of this plant and are the primary source of rootstocks globally for a variety of avocado cultivars, such as the Hass avocado. Here, we report the isolation of 5005 ESTs from the 5' ends of P. americana var. drymifolia seed cDNA clones representing 1584 possible unigenes. These avocado seed ESTs were compared with the avocado flower EST library, and we detected several genes that are expressed either in both tissues or only in the seed. The snakin gene, which encodes an element of the innate immune response in plants, was one of those most frequently found among the seed ESTs, and this suggests that it is abundantly expressed in the avocado seed. We expressed the snakin gene in a heterologous system, namely the bovine endothelial cell line BVE-E6E7. Conditioned media from transfected BVE-E6E7 cells showed antimicrobial activity against strains of Escherichia coli and Staphylococcus aureus. This is the first study of the function of the snakin gene in plant seed tissue, and our observations suggest that this gene might play a protective role in the avocado seed.

  3. Gene cloning and functional characterization of four novel antimicrobial-like peptides from scorpions of the family Vaejovidae.

    Science.gov (United States)

    Ramírez-Carreto, Santos; Quintero-Hernández, Verónica; Jiménez-Vargas, Juana María; Corzo, Gerardo; Possani, Lourival D; Becerril, Baltazar; Ortiz, Ernesto

    2012-04-01

    From the cDNA libraries made from the venom glands of two scorpions belonging to the Vaejovidae family, four different putative non disulfide-bridged antimicrobial peptides were identified: VmCT1 and VmCT2 from Vaejovis mexicanus smithi plus VsCT1 and VsCT2 from Vaejovis subcristatus. These short peptides (with only 13 amino acid residues each) share important amino acid sequence similarities among themselves and with other reported antimicrobial peptides, but their biological activities vary dramatically. This communication reports the cloning, chemical synthesis and characterization of these peptides. Two peptides, VmCT1 and VmCT2 showed broad-spectrum antibacterial activity with minimum inhibitory concentrations MICs in the range of 5-25 μM and 10-20 μM respectively, whereas their hemolytic activity at these concentrations was low. Structure-function relationships that might determine the differences in activities are discussed.

  4. Genetic lineages, antimicrobial resistance, and virulence in Staphylococcus aureus of meat samples in Spain: analysis of immune evasion cluster (IEC) genes.

    Science.gov (United States)

    Benito, Daniel; Gómez, Paula; Lozano, Carmen; Estepa, Vanesa; Gómez-Sanz, Elena; Zarazaga, Myriam; Torres, Carmen

    2014-05-01

    The objective of this study was to determine the rate of contamination by Staphylococcus aureus in 100 meat samples obtained during 2011-2012 in La Rioja (Northern Spain), to analyze their content in antimicrobial resistance and virulence genes, as well as in immune evasion cluster (IEC) genes, and to type recovered isolates. Seven of 100 samples (7%) contained S. aureus: 6 samples harbored methicillin-susceptible S. aureus (MSSA) and 1 pork sample harbored methicillin-resistant S. aureus (MRSA). The MRSA isolate corresponded to the ST398 genetic lineage with a multidrug resistance profile and the absence of human IEC genes, which pointed to a typical livestock-associated MRSA profile. MRSA isolate was ascribed to the spa-type t011, agr-type I, and SCCmec-V and showed resistance to erythromycin, clindamycin, tetracycline, and streptomycin, in addition to β-lactams. The remaining six MSSA strains belonged to different sequence types and clonal complexes (three isolates ST45/CC45, one ST617/CC45, one ST5/CC5, and one ST109/CC9), being susceptible to most antibiotics tested but showing a wide virulence gene profile. Five of the six MSSA strains (except ST617/CC45) contained the enterotoxin egc-cluster or egc-like-cluster genes, and strain ST109/CC9 contained eta gene (encoding exfoliatin A). The presence of human IEC genes in MSSA strains (types B and D) points to a possible contamination of meat samples from an undefined human source. The presence of S. aureus with enterotoxin genes and MRSA in food samples might have implications in public health. The IEC system could be a good marker to follow the S. aureus contamination source in meat food products.

  5. Genotypic and Antimicrobial Susceptibility of Carbapenem-Resistant Acinetobacter baumannii: Analysis of ISAba Elements and blaOXA-23-like Genes Including A New Variant

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    Abbas eBahador

    2015-11-01

    Full Text Available Carbapenem-resistant Acinetobacter baumannii (CR-AB causes serious nosocomial infections, especially in ICU wards of hospitals, worldwide. Expression of blaOXA genes is the chief mechanism of conferring carbapenem resistance among CR-AB. Although some blaOXA genes have been studied among CR-AB isolates from Iran, their blaOXA-23-like genes have not been investigated. We used a multiplex-PCR to detect Ambler class A, B, and D carbapenemases of 85 isolates, and determined that 34 harbored blaOXA-23-like genes. Amplified fragment length polymorphism (AFLP genotyping, followed by DNA sequencing of blaOXA-23-like amplicons of CR-AB from each AFLP group was used to characterize their blaOXA-23-like genes. We also assessed the antimicrobial susceptibility pattern of CR-AB isolates, and tested whether they harbored insertion sequences ISAba1 and ISAba4. Sequence comparison with reference strain A. baumannii (NCTC12156 revealed five types of mutations in blaOXA-23-like genes; including one novel variant and four mutants that were already reported from China and the USA. All of the blaOXA-23-like genes mutations were associated with increased minimum inhibitory concentrations (MICs against imipenem. ISAba1 and ISAba4 sequences were detected upstream of blaOXA-23 genes in 19% and 7% of isolates, respectively. The isolation of CR-AB with new blaOXA-23 mutations including some that have been reported from the USA and China highlights CR-AB pervasive distribution, which underscores the importance of concerted national and global efforts to control the spread of CR-AB isolates worldwide.

  6. Antimicrobial resistance and molecular characterization of virulence genes, phylogenetic groups of Escherichia coli isolated from diarrheic and healthy camel-calves in Tunisia.

    Science.gov (United States)

    Bessalah, Salma; Fairbrother, John Morris; Salhi, Imed; Vanier, Ghyslaine; Khorchani, Touhami; Seddik, Mouldi Mabrouk; Hammadi, Mohamed

    2016-12-01

    This study was conducted to determine the prevalence of virulence genes, serogroups, antimicrobial resistance and phylogenetic groups of Escherichia coli strains isolated from diarrheic and healthy camel calves in Tunisia. From 120 fecal samples (62 healthy and 58 diarrheic camel calves aged less than 3 months), 70 E. coli isolates (53 from diarrheic herds and 17 from healthy herds) were examined by PCR for detection of the virulence genes associated with pathogenic E. coli in animals. A significantly greater frequency of the f17 gene was observed in individual camels and in herds with diarrhea, this gene being found in 44.7% and 41.5% of isolates from camels and herds with diarrhea versus 22.5% and 11.7% in camels (p=0.05) and herds without diarrhea (p=0.02). The aida, cnf1/2, f18, stx2 and paa genes were found only in isolates from camels with diarrhea, although at a low prevalence, 1.8%, 3.7%, 1.8%, 3.7% and 11.3%, respectively. Prevalence of afa8, cdtB, eae, east1, iroN, iss, kpsMTII, paa, sfa, tsh and papC genes did not differ significantly between herds with or without diarrhea. Genes coding for faeG, fanC, f41, estI, estII, CS31a and eltA were not detected in any isolates. All isolates were sensitive to amikacin, chloramphenicol, ciprofloxacin, gentamicin and ceftiofur and the highest frequency of resistance was observed to tetracycline, and ampicillin (52.8% and 37.1% respectively). The phylogenetic groups were identified by conventional triplex PCR. Results showed that E. coli strains segregated mainly in phylogenetic group B1, 52.8% in diarrheic herds and 52.9% in healthy herds.

  7. Antimicrobial Resistance

    Science.gov (United States)

    ... emergence and spread of antibacterial resistance, including optimal use of antibiotics in both humans and animals. A global action plan on antimicrobial resistance was adopted by Member States at the ...

  8. Cooperative Transcriptional Activation of Antimicrobial Genes by STAT and NF-κB Pathways by Concerted Recruitment of the Mediator Complex

    Directory of Open Access Journals (Sweden)

    Sebastian Wienerroither

    2015-07-01

    Full Text Available The transcriptional response to infection with the bacterium Listeria monocytogenes (Lm requires cooperative signals of the type I interferon (IFN-I-stimulated JAK-STAT and proinflammatory NF-κB pathways. Using ChIP-seq analysis, we define genes induced in Lm-infected macrophages through synergistic transcriptional activation by NF-κB and the IFN-I-activated transcription factor ISGF3. Using the Nos2 and IL6 genes as prime examples of this group, we show that NF-κB functions to recruit enzymes that establish histone marks of transcriptionally active genes. In addition, NF-κB regulates transcriptional elongation by employing the mediator kinase module for the recruitment of the pTEFb complex. ISGF3 has a major role in associating the core mediator with the transcription start as a prerequisite for TFIID and RNA polymerase II (Pol II binding. Our data suggest that the functional cooperation between two major antimicrobial pathways is based on promoter priming by NF-κB and the engagement of the core mediator for Pol II binding by ISGF3.

  9. Population structure and characterisation of Staphylococcus aureus from bacteraemia at multiple hospitals in China: association between antimicrobial resistance, toxin genes and genotypes.

    Science.gov (United States)

    He, Wenqiang; Chen, Hongbin; Zhao, Chunjiang; Zhang, Feifei; Li, Henan; Wang, Qi; Wang, Xiaojuan; Wang, Hui

    2013-09-01

    Staphylococcus aureus from bacteraemia at multiple hospitals in China were genetically characterised to improve understanding of its epidemiology. A total of 236 consecutive, non-duplicate S. aureus bacteraemia isolates were collected at 16 Chinese hospitals. Isolates were characterised by antimicrobial resistance, 19 toxin genes, agr alleles, multilocus sequence typing and spa typing. The prevalence of meticillin-resistant S. aureus (MRSA) was 47.5% (112/236). Forty-two sequence types (STs) and 63 spa types were identified, including 14 STs and 14 spa types for MRSA. Clonal complex (CC) 8, CC5, ST7 and CC188 accounted for 67.4% of the isolates. ST239-t030/t037-SCCmecIII-agrI was the predominant MRSA genotype (50%), followed by ST5-t002/t570-SCCmecII-agrII (8%). A vancomycin MIC ≥ 1mg/L was detected significantly more often in ST5-SCCmecII and ST239-t037-SCCmecIII, whereas rifampicin resistance was overwhelmingly associated with ST239-t030-SCCmecIII (Paureus (MSSA) were ST7-t091/t796-agrI (16.1%), ST188-t189-agrI (12.1%) and ST398-t571/t034-agrI (5.6%). Toxin genes were identified in 95.8% of isolates and formed 89 toxin gene profiles. The toxin genes sea, selk, selq and sell were significantly more common in MRSA, whilst tsst-1, seb, sed, selm, seln, selp and selj were more prevalent in MSSA (Ptoxin gene profiles.

  10. Gold nanoparticles-based electrochemical method for the detection of protein kinase with a peptide-like inhibitor as the bioreceptor

    Science.gov (United States)

    Sun, Kai; Chang, Yong; Zhou, Binbin; Wang, Xiaojin; Liu, Lin

    2017-01-01

    This article presents a general method for the detection of protein kinase with a peptide-like kinase inhibitor as the bioreceptor, and it was done by converting gold nanoparticles (AuNPs)-based colorimetric assay into sensitive electrochemical analysis. In the colorimetric assay, the kinase-specific aptameric peptide triggered the aggregation of AuNPs in solution. However, the specific binding of peptide to the target protein (kinase) inhibited its ability to trigger the assembly of AuNPs. In the electrochemical analysis, peptides immobilized on a gold electrode and presented as solution triggered together the in situ formation of AuNPs-based network architecture on the electrode surface. Nevertheless, the formation of peptide–kinase complex on the electrode surface made the peptide-triggered AuNPs assembly difficult. Electrochemical impedance spectroscopy was used to measure the change in surface property in the binding events. When a ferrocene-labeled peptide (Fc-peptide) was used in this design, the network of AuNPs/Fc-peptide produced a good voltammetric signal. The competitive assay allowed for the detection of protein kinase A with a detection limit of 20 mU/mL. This work should be valuable for designing novel optical or electronic biosensors and likely lead to many detection applications.

  11. The shrimp IKK-NF-κB signaling pathway regulates antimicrobial peptide expression and may be subverted by white spot syndrome virus to facilitate viral gene expression.

    Science.gov (United States)

    Wang, Pei-Hui; Gu, Zhi-Hua; Wan, Ding-Hui; Liu, Bo-Du; Huang, Xian-De; Weng, Shao-Ping; Yu, Xiao-Qiang; He, Jian-Guo

    2013-09-01

    The IκB kinases IKKα and IKKβ and the IKK-related kinases TANK-binding kinase 1 (TBK1) and IKKε are the master regulators of the NF-κB signaling pathway. Although this pathway has been extensively studied in mammals, less attention has been paid in crustaceans, which have significant economic value. Here, we report the cloning and functional studies of two IKK homologs, LvIKKβ and LvIKKε, from Pacific white shrimp, Litopenaeus vannamei. LvIKKβ and LvIKKε mRNAs are widely expressed in different tissues and are responsive to white spot syndrome virus (WSSV) infection. When overexpressed in Drosophila S2 cells, LvIKKβ but not LvIKKε activates the promoters of NF-κB pathway-controlled antimicrobial peptide genes (AMPs), such as the Penaeidins (PENs). In HEK 293T cells, both LvIKKβ and LvIKKε activate an NF-κB reporter. The silencing of LvIKKβ or LvIKKε using double-stranded RNA (dsRNA)-mediated RNA interference (RNAi) decreases the expression of L. vannamei AMPs, including PENs, lysozyme and crustins. Intriguingly, LvIKKβ- or LvIKKε-silenced L. vannamei are resistant to WSSV infection. We hypothesized that successful infection with WSSV requires the activation of the IKK-NF-κB signaling pathway to modulate viral gene expression. We constructed luciferase reporters for 147 WSSV genes. By screening, we found that the WSV051, WSV059, WSV069, WSV083, WSV090, WSV107, WSV244, WSV303, WSV371 and WSV445 promoters can be activated by LvIKKβ or LvIKKε in Drosophila S2 cells. Taken together, our results reveal that LvIKKβ and LvIKKε may participate in the regulation of shrimp AMPs and that WSSV may subvert the L. vannamei IKK-NF-κB signaling pathway to facilitate viral gene expression.

  12. The Erwinia amylovora PhoPQ system is involved in resistance to antimicrobial peptide and suppresses gene expression of two novel type III secretion systems.

    Science.gov (United States)

    Nakka, Sridevi; Qi, Mingsheng; Zhao, Youfu

    2010-10-20

    The PhoPQ system is a pleiotropic two-component signal transduction system that controls many pathogenic properties in several mammalian and plant pathogens. Three different cues have been demonstrated to activate the PhoPQ system including a mild acidic pH, antimicrobial peptides, and low Mg(2+). In this study, our results showed that phoPQ mutants were more resistant to strong acidic conditions (pH 4.5 or 5) than that of the wild-type (WT) strain, suggesting that this system in Erwinia amylovora may negatively regulate acid resistance gene expression. Furthermore, the PhoPQ system negatively regulated gene expression of two novel type III secretion systems in E. amylovora. These results are in contrast to those reported for the PhoPQ system in Salmonella and Xanthomonas, where it positively regulates type III secretion system and acid resistance. In addition, survival of phoPQ mutants was about 10-fold lower than that of WT when treated with cecropin A at pH 5.5, suggesting that the PhoPQ system renders the pathogen more resistant to cecropin A.

  13. Safety assessment of the Clostridium butyricum MIYAIRI 588® probiotic strain including evaluation of antimicrobial sensitivity and presence of Clostridium toxin genes in vitro and teratogenicity in vivo.

    Science.gov (United States)

    Isa, K; Oka, K; Beauchamp, N; Sato, M; Wada, K; Ohtani, K; Nakanishi, S; McCartney, E; Tanaka, M; Shimizu, T; Kamiya, S; Kruger, C; Takahashi, M

    2016-08-01

    Probiotics are live microorganisms ingested for the purpose of conferring a health benefit on the host. Development of new probiotics includes the need for safety evaluations that should consider factors such as pathogenicity, infectivity, virulence factors, toxicity, and metabolic activity. Clostridium butyricum MIYAIRI 588(®) (CBM 588(®)), an anaerobic spore-forming bacterium, has been developed as a probiotic for use by humans and food animals. Safety studies of this probiotic strain have been conducted and include assessment of antimicrobial sensitivity, documentation of the lack of Clostridium toxin genes, and evaluation of CBM 588(®) on reproductive and developmental toxicity in a rodent model. With the exception of aminoglycosides, to which anaerobes are intrinsically resistant, CBM 588(®) showed sensitivity to all antibiotic classes important in human and animal therapeutics. In addition, analysis of the CBM 588(®) genome established the absence of genes for encoding for α, β, or ε toxins and botulin neurotoxins types A, B, E, or F. There were no deleterious reproductive and developmental effects observed in mice associated with the administration of CBM 588(®) These data provide further support for the safety of CBM 588(®) for use as a probiotic in animals and humans.

  14. Antimicrobial polymers.

    Science.gov (United States)

    Jain, Anjali; Duvvuri, L Sailaja; Farah, Shady; Beyth, Nurit; Domb, Abraham J; Khan, Wahid

    2014-12-01

    Better health is basic requirement of human being, but the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern science. Infections by pathogenic microorganisms are of great concern in many fields such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications (e.g., water purification systems, textiles, food packaging and storage, major or domestic appliances etc.) Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Recently, they gained considerable interest for both academic research and industry and were found to be better than their small molecular counterparts in terms of enhanced efficacy, reduced toxicity, minimized environmental problems, resistance, and prolonged lifetime. Hence, efforts have focused on the development of antimicrobial polymers with all desired characters for optimum activity. In this Review, an overview of different antimicrobial polymers, their mechanism of action, factors affecting antimicrobial activity, and application in various fields are given. Recent advances and the current clinical status of these polymers are also discussed.

  15. Source-Related Effects of Wastewater on Transcription Factor (AhR, CAR and PXR-Mediated Induction of Gene Expression in Cultured Rat Hepatocytes and Their Association with the Prevalence of Antimicrobial-Resistant Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Keerthi S Guruge

    Full Text Available Extracts of wastewater collected from 4 sewage treatment plants (STPs receiving effluents from different sources in South India were investigated for their levels of transcription factor-mediated gene induction in primary cultured rat hepatocytes. In addition, the relation between gene induction levels and the prevalence of antimicrobial-resistant Escherichia coli (E. coli in wastewater was examined. STP-3, which treats only hospital wastewater, exhibited significantly greater induction potency of all 6 drug metabolizing cytochrome P450 (CYP genes examined, CYP1A1, 1A2, 1B1, 2B15, 3A1, and 3A2, whereas the wastewater at STP-1, which exclusively receives domestic sewage, showed significantly diminished levels of induction of 3 CYP genes when compared to the levels of CYP induction at STP-2, which receives mixed wastewater. Samples collected during the monsoon season showed a significantly altered gene induction capacity compared to that of samples from the pre-monsoon period. The data suggest that the toxicity of wastewater in STPs was not significantly diminished during the treatment process. The chemical-gene interaction data predicted that a vast number of chemicals present in the wastewater would stimulate the genes studied in the rat hepatocytes. The multivariable logistic regression analysis demonstrated that the prevalence of isolates resistant to cefotaxime, imipenem and streptomycin was significantly correlated with the levels of induction of at least three CYP-isozymes in STP wastewater. In addition, the resistance of isolates in treatment plants was not altered by the treatment steps, whereas the sampling season did have an impact on the resistance to specific antimicrobials. The identification of receptor-mediated gene regulation capacities offers important data not limited to the (synergistic physiological role of chemicals in biological systems but may provide new insight into the link between the effects of known/unknown drugs and

  16. Source-Related Effects of Wastewater on Transcription Factor (AhR, CAR and PXR)-Mediated Induction of Gene Expression in Cultured Rat Hepatocytes and Their Association with the Prevalence of Antimicrobial-Resistant Escherichia coli.

    Science.gov (United States)

    Guruge, Keerthi S; Yamanaka, Noriko; Sonobe, Miyuki; Fujizono, Wataru; Yoshioka, Miyako; Akiba, Masato; Yamamoto, Takehisa; Joshua, Derrick I; Balakrishna, Keshava; Yamashita, Nobuyoshi; Kannan, Kurunthachalam; Tsutsui, Toshiyuki

    2015-01-01

    Extracts of wastewater collected from 4 sewage treatment plants (STPs) receiving effluents from different sources in South India were investigated for their levels of transcription factor-mediated gene induction in primary cultured rat hepatocytes. In addition, the relation between gene induction levels and the prevalence of antimicrobial-resistant Escherichia coli (E. coli) in wastewater was examined. STP-3, which treats only hospital wastewater, exhibited significantly greater induction potency of all 6 drug metabolizing cytochrome P450 (CYP) genes examined, CYP1A1, 1A2, 1B1, 2B15, 3A1, and 3A2, whereas the wastewater at STP-1, which exclusively receives domestic sewage, showed significantly diminished levels of induction of 3 CYP genes when compared to the levels of CYP induction at STP-2, which receives mixed wastewater. Samples collected during the monsoon season showed a significantly altered gene induction capacity compared to that of samples from the pre-monsoon period. The data suggest that the toxicity of wastewater in STPs was not significantly diminished during the treatment process. The chemical-gene interaction data predicted that a vast number of chemicals present in the wastewater would stimulate the genes studied in the rat hepatocytes. The multivariable logistic regression analysis demonstrated that the prevalence of isolates resistant to cefotaxime, imipenem and streptomycin was significantly correlated with the levels of induction of at least three CYP-isozymes in STP wastewater. In addition, the resistance of isolates in treatment plants was not altered by the treatment steps, whereas the sampling season did have an impact on the resistance to specific antimicrobials. The identification of receptor-mediated gene regulation capacities offers important data not limited to the (synergistic) physiological role of chemicals in biological systems but may provide new insight into the link between the effects of known/unknown drugs and prevalence of

  17. Gold nanoparticles-based electrochemical method for the detection of protein kinase with a peptide-like inhibitor as the bioreceptor

    Directory of Open Access Journals (Sweden)

    Sun K

    2017-03-01

    Full Text Available Kai Sun, Yong Chang, Binbin Zhou, Xiaojin Wang, Lin Liu Henan Province of Key Laboratory of New Optoelectronic Functional Materials, College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan, People’s Republic of China Abstract: This article presents a general method for the detection of protein kinase with a peptide-like kinase inhibitor as the bioreceptor, and it was done by converting gold nanoparticles (AuNPs-based colorimetric assay into sensitive electrochemical analysis. In the colorimetric assay, the kinase-specific aptameric peptide triggered the aggregation of AuNPs in solution. However, the specific binding of peptide to the target protein (kinase inhibited its ability to trigger the assembly of AuNPs. In the electrochemical analysis, peptides immobilized on a gold electrode and presented as solution triggered together the in situ formation of AuNPs-based network architecture on the electrode surface. Nevertheless, the formation of peptide–kinase complex on the electrode surface made the peptide-triggered AuNPs assembly difficult. Electrochemical impedance spectroscopy was used to measure the change in surface property in the binding events. When a ferrocene-labeled peptide (Fc-peptide was used in this design, the network of AuNPs/Fc-peptide produced a good voltammetric signal. The competitive assay allowed for the detection of protein kinase A with a detection limit of 20 mU/mL. This work should be valuable for designing novel optical or electronic biosensors and likely lead to many detection applications. Keywords: electrochemical biosensor, colorimetric assay, gold nanoparticle, aptameric peptide, protein kinase A, signal amplification 

  18. Antimicrobial Resistance Pattern and Their Beta-Lactamase Encoding Genes among Pseudomonas aeruginosa Strains Isolated from Cancer Patients

    Directory of Open Access Journals (Sweden)

    Mai M. Zafer

    2014-01-01

    Full Text Available This study was designed to investigate the prevalence of metallo-β-lactamases (MBL and extended-spectrum β-lactamases (ESBL in P. aeruginosa isolates collected from two different hospitals in Cairo, Egypt. Antibiotic susceptibility testing and phenotypic screening for ESBLs and MBLs were performed on 122 P. aeruginosa isolates collected in the period from January 2011 to March 2012. MICs were determined. ESBLs and MBLs genes were sought by PCR. The resistant rate to imipenem was 39.34%. The resistance rates for P. aeruginosa to cefuroxime, cefoperazone, ceftazidime, aztreonam, and piperacillin/tazobactam were 87.7%, 80.3%, 60.6%, 45.1%, and 25.4%, respectively. Out of 122 P. aeruginosa, 27% and 7.4% were MBL and ESBL, respectively. The prevalence of blaVIM-2, blaOXA-10-, blaVEB-1, blaNDM-, and blaIMP-1-like genes were found in 58.3%, 41.7%, 10.4%, 4.2%, and 2.1%, respectively. GIM-, SPM-, SIM-, and OXA-2-like genes were not detected in this study. OXA-10-like gene was concomitant with VIM-2 and/or VEB. Twelve isolates harbored both OXA-10 and VIM-2; two isolates carried both OXA-10 and VEB. Only one strain contained OXA-10, VIM-2, and VEB. In conclusion, blaVIM-2- and blaOXA-10-like genes were the most prevalent genes in P. aeruginosa in Egypt. To our knowledge, this is the first report of blaVIM-2, blaIMP-1, blaNDM, and blaOXA-10 in P. aeruginosa in Egypt.

  19. Characterization of coagulase-negative staphylococcus species from cows' milk and environment based on bap, icaA, and mecA genes and phenotypic susceptibility to antimicrobials and teat dips.

    Science.gov (United States)

    Piessens, V; De Vliegher, S; Verbist, B; Braem, G; Van Nuffel, A; De Vuyst, L; Heyndrickx, M; Van Coillie, E

    2012-12-01

    The aim of this study was to investigate whether the main coagulase-negative staphylococci (CNS) species involved in bovine intramammary infections (IMI) possess specific characteristics that promote colonization of the udder. Virulence markers associated with biofilm formation, antimicrobial resistance, and biocide tolerance were compared between typically contagious CNS species (Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus simulans) and those rarely causing IMI (Staphylococcus sciuri, Staphylococcus equorum, and others) to find possible associations with pathogenicity. Coagulase-negative staphylococci isolates (n=366) belonging to 22 different species were analyzed by PCR for the presence of the biofilm-associated genes bap and icaA, and the methicillin resistance gene mecA. A selection of 82 isolates was additionally tested for their susceptibility to 5 antibiotics and 2 commercial teat dip products. Minimum inhibitory concentrations of antimicrobials were determined by Etest (AB bioMérieux, Marcy l'Etoile, France), and a microdilution method was optimized to determine minimum biocidal concentrations of teat dips. The bap, icaA, and mecA genes were detected significantly more in isolates from CNS species typically living in the cows' environment than in isolates from IMI-causing species. Antimicrobial resistance was mainly against erythromycin (23%) or oxacillin (16%), and was detected more often in the environmental species. The isolates least susceptible to the teat dips belonged to the IMI-causing species Staph. chromogenes and Staph. simulans. We concluded that carriage of biofilm genes and antimicrobial resistance were not associated with the ability to colonize the mammary gland because free-living CNS species constituted a more significant reservoir of biofilm and resistance determinants than did IMI-causing species. In contrast, increased tolerance to biocides may favor the establishment of

  20. Antimicrobial susceptibility and antibiotic resistance gene transfer analysis of foodborne, clinical, and environmental Listeria spp. isolates including Listeria monocytogenes.

    Science.gov (United States)

    Bertsch, David; Muelli, Mirjam; Weller, Monika; Uruty, Anaïs; Lacroix, Christophe; Meile, Leo

    2014-02-01

    The aims of this study were to assess antibiotic resistance pheno- and genotypes in foodborne, clinical, and environmental Listeria isolates, as well as to elucidate the horizontal gene transfer potential of detected resistance genes. A small fraction of in total 524 Listeria spp. isolates (3.1%) displayed acquired antibiotic resistance mainly to tetracycline (n = 11), but also to clindamycin (n = 4) and trimethoprim (n = 3), which was genotypically confirmed. In two cases, a tetracycline resistance phenotype was observed together with a trimethoprim resistance phenotype, namely in a clinical L. monocytogenes strain and in a foodborne L. innocua isolate. Depending on the applied guidelines, a differing number of isolates (n = 2 or n = 20) showed values for ampicillin that are on the edge between intermediate susceptibility and resistance. Transferability of the antibiotic resistance genes from the Listeria donors, elucidated in vitro by filter matings, was demonstrated for genes located on transposons of the Tn916 family and for an unknown clindamycin resistance determinant. Transfer rates of up to 10(-5) transconjugants per donor were obtained with a L. monocytogenes recipient and up to 10(-7) with an Enterococcus faecalis recipient, respectively. Although the prevalence of acquired antibiotic resistance in Listeria isolates from this study was rather low, the transferability of these resistances enables further spread in the future. This endorses the importance of surveillance of L. monocytogenes and other Listeria spp. in terms of antibiotic susceptibility.

  1. Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ali Adem Bahar

    2013-11-01

    Full Text Available The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill “superbugs” emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs, a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics.

  2. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Gottlieb, Caroline Trebbien; Vestergaard, Martin;

    2015-01-01

    The rapid rise in antibiotic-resistant pathogens is causing increased health concerns, and consequently there is an urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs), which have been isolated from a wide range of organisms, represent a very promising class of novel antimic...

  3. Antimicrobial susceptibility and rRNA gene restriction patterns among Staphylococcus intermedius from healthy dogs and from dogs suffering from pyoderma or otitis externa.

    Science.gov (United States)

    Pedersen, K; Wegener, H C

    1995-01-01

    A total of 60 Staphylococcus intermedius strains from dogs were investigated by their sensitivity to various antibiotics (50 strains) and by their rRNA gene restriction patterns (ribotyping) (60 strains). Fifteen isolates were from healthy dogs, 9 with otitis externa, and 36 with pyoderma, including 10 strains from a previous study. Sixty per cent of the 50 strains tested for antibiotic susceptibility demonstrated resistance to penicillin, 24% to spiramycin, 20% to tetracycline, 16% to chloramphenicol, and 2% to fucidic acid. All isolates were susceptible to amoxycillin with clavulanic acid, enrofloxacin, and sulphonamides with trimethoprim. There were no significant differences in antimicrobial susceptibility patterns observed among isolates from pyoderma, otitis externa or healthy dogs. Among the 60 strains studied by ribotyping, 10 different ribotypes were identified: 6 different ribotypes among isolates from otitis externa, 8 among isolates from pyoderma, and 5 among isolates from healthy dogs. One ribotype (profile C) was dominant among the isolates from healthy dogs while another ribotype (profile A) was dominant among strains from dogs suffering from pyoderma. This profile was not demonstrated in any of the strains from healthy dogs. From 5 different dogs suffering from pyoderma, 2 different clones were demonstrated based on their plasmid profile and antibiogram. In these dogs 1 of the clones always belonged to ribotype A. The results concerning strains of S. intermedius isolated from furunculosis suggest the existence of distinct subpopulations with different pathogenicity to dogs.

  4. Molecular cloning and expression analysis of liver-expressed antimicrobial peptide 1 (LEAP-1) and LEAP-2 genes in the blunt snout bream (Megalobrama amblycephala).

    Science.gov (United States)

    Liang, Tao; Ji, Wei; Zhang, Gui-Rong; Wei, Kai-Jian; Feng, Ke; Wang, Wei-Min; Zou, Gui-Wei

    2013-08-01

    Liver-expressed antimicrobial peptide 1 (LEAP-1) and LEAP-2 are widespread in fish and extremely important components of the host innate immune system. In this study, full-length cDNAs of LEAP-1 and LEAP-2 were cloned and sequenced from blunt snout bream, Megalobrama amblycephala. The open reading frames (ORF) of LEAP-1 and LEAP-2 genes encode putative peptides of 94 and 92 amino acids, which possess eight and four conserved cysteine residues, respectively. The homologous identities of deduced amino acid sequences show that the LEAP-1 and LEAP-2 of blunt snout bream share considerable similarity with those of grass carp. The mRNA expressions of LEAP-1 and LEAP-2 were detectable at different early developmental stages of blunt snout bream and varied with embryonic and larval growth. LEAP-1 and LEAP-2 were expressed in a wide range of adult tissues, with the highest expression levels in the liver and midgut, respectively. Bacterial challenge experiments showed that the levels of LEAP-1 and LEAP-2 mRNA expression were up-regulated in the liver, spleen, gill and brain of juvenile blunt snout bream. These results indicate that the LEAP-1 and LEAP-2 may play important roles in early development of embryos and fry, and may contribute to the defense against the pathogenic bacterial invasion. This study will further our understanding of the function of LEAP-1 and LEAP-2 and the molecular mechanism of innate immunity in teleosts.

  5. Antimicrobial agent of susceptibilities and antiseptic resistance gene distribution among methicillin-resistant Staphylococcus aureus isolates from patients with impetigo and staphylococcal scalded skin syndrome.

    Science.gov (United States)

    Noguchi, Norihisa; Nakaminami, Hidemasa; Nishijima, Setsuko; Kurokawa, Ichiro; So, Hiromu; Sasatsu, Masanori

    2006-06-01

    The susceptibilities to antimicrobial agents of and distributions of antiseptic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) strains isolated between 1999 and 2004 in Japan were examined. The data of MRSA strains that are causative agents of impetigo and staphylococcal scalded skin syndrome (SSSS) were compared with those of MRSA strains isolated from patients with other diseases. The susceptibilities to antiseptic agents in MRSA isolates from patients with impetigo and SSSS were higher than those in MRSA isolates from patients with other diseases. The distribution of the qacA/B genes in MRSA strains isolated from patients with impetigo and SSSS (1.3%, 1/76) was remarkably lower than that in MRSA strains isolated from patients with other diseases (45.9%, 95/207). Epidemiologic typings of staphylococcal cassette chromosome mec (SCCmec) and pulsed-field gel electrophoresis (PFGE) showed that MRSA strains isolated from patients with impetigo and SSSS had type IV SCCmec (75/76), except for one strain, and 64.5% (49/76) of the strains had different PFGE types. In addition, the patterns of restriction digestion of all tested qacA/B plasmid in MRSA isolates having different PFGE types were identical. The results showed that a specific MRSA clone carrying qacA/B was not prevalent, but qacA/B was spread among health care-associated MRSA strains. Therefore, it was concluded that the lower distribution rate of qacA/B resulted in higher susceptibilities to cationic antiseptic agents in MRSA isolated from patients with impetigo and SSSS.

  6. Effect of phosphoglucosamine mutase on biofilm formation and antimicrobial susceptibilities in M. smegmatis glmM gene knockdown strain.

    Directory of Open Access Journals (Sweden)

    Jian Kang

    Full Text Available UDP-N-acetylglucosamine (UDP-GlcNAc is a direct glycosyl donor of linker unit (L-Rhamnose-D-GlcNAc and an essential precursor of peptidoglycan in mycobacteria. Phosphoglucosamine mutase (GlmM is involved in the formation of glucosamine-1-phosphate from glucosamine-6-phosphate, the second step in UDP-GlcNAc biosynthetic pathway. We have demonstrated that GlmM protein is essential for the growth of M. smegmatis. To facilitate the analysis of the GlmM protein function in mycobacteria, a tetracycline inducible M. smegmatis glmM gene knockdown strain was constructed by using an antisense RNA technology. After induction with 20 ng/ml tetracycline, the expression of GlmM protein in glmM gene knockdown strain was significantly decreased, resulting in a decline of cell growth. The morphological changes of glmM gene knockdown strain induced with 20 ng/ml tetracycline have been observed by scanning electron microscope and transmission electron microscope. Furthermore, insufficient GlmM protein reduced the biofilm formation and increased the sensitivity to isoniazid and ethambutol in M. smegmatis, indicating that GlmM protein had effect on the biofilm formation and the senstivity to some anti-tuberculosis drugs targeting the cell wall. These results provide a new insight on GlmM functions in mycobacteria, suggesting that GlmM could be a potential target for development of new anti-tuberculosis drug.

  7. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... how antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial ...

  8. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it ... Veterinary Medicine is cited as the corporate author. Animation Animation of Antimicrobial Resistance (WMV - 19.2MB) 9: ...

  9. Animation of Antimicrobial Resistance

    Science.gov (United States)

    ... Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... produced a nine-minute animation explaining how antimicrobial resistance both emerges and proliferates among bacteria. Over time, ...

  10. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  11. Animation of Antimicrobial Resistance

    Science.gov (United States)

    ... Animal & Veterinary Cosmetics Tobacco Products Animal & ... antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development ...

  12. Tachykinin-Related Peptides Share a G Protein-Coupled Receptor with Ion Transport Peptide-Like in the Silkworm Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Chiaki Nagai-Okatani

    Full Text Available Recently, we identified an orphan Bombyx mori neuropeptide G protein-coupled receptor (BNGR-A24 as an ion transport peptide-like (ITPL receptor. BNGR-A24 belongs to the same clade as BNGR-A32 and -A33, which were recently identified as natalisin receptors. Since these three BNGRs share high similarities with known receptors for tachykinin-related peptides (TRPs, we examined whether these BNGRs can function as physiological receptors for five endogenous B. mori TRPs (TK-1-5. In a heterologous expression system, BNGR-A24 acted as a receptor for all five TRPs. In contrast, BNGR-A32 responded only to TK-5, and BNGR-A33 did not respond to any of the TRPs. These findings are consistent with recent studies on the ligand preferences for B. mori natalisins. Furthermore, we evaluated whether the binding of ITPL and TRPs to BNGR-A24 is competitive by using a Ca2+ imaging assay. Concomitant addition of a TRP receptor antagonist, spantide I, reduced the responses of BNGR-A24 not only to TK-4 but also to ITPL. The results of a binding assay using fluorescent-labeled BNGR-A24 and ligands demonstrated that the binding of ITPL to BNGR-A24 was inhibited by TK-4 as well as by spantide I, and vice versa. In addition, the ITPL-induced increase in cGMP levels of BNGR-A24-expressing BmN cells was suppressed by the addition of excess TK-4 or spantide I. The intracellular levels of cAMP and cGMP, as second messenger candidates of the TRP signaling, were not altered by the five TRPs, suggesting that these peptides act via different signaling pathways from cAMP and cGMP signaling at least in BmN cells. Taken together, the present findings suggest that ITPL and TRPs are endogenous orthosteric ligands of BNGR-A24 that may activate discrete signaling pathways. This receptor, which shares orthosteric ligands, may constitute an important model for studying ligand-biased signaling.

  13. Bombyx mori E26 transformation-specific 2 (BmEts2), an Ets family protein, represses Bombyx mori Rels (BmRels)-mediated promoter activation of antimicrobial peptide genes in the silkworm Bombyx mori.

    Science.gov (United States)

    Tanaka, H; Sagisaka, A; Suzuki, N; Yamakawa, M

    2016-10-01

    E26 transformation-specific (Ets) family transcription factors are known to play roles in various biological phenomena, including immunity, in vertebrates. However, the mechanisms by which Ets proteins contribute to immunity in invertebrates remain poorly understood. In this study, we identified a cDNA encoding BmEts2, which is a putative orthologue of Drosophila Yan and human translocation-ets-leukemia/Ets-variant gene 6, from the silkworm Bombyx mori. Expression of the BmEts2 gene was significantly increased in the fat bodies of silkworm larvae in response to injection with Escherichia coli and Staphylococcus aureus. BmEts2 overexpression dramatically repressed B. mori Rels (BmRels)-mediated promoter activation of antimicrobial peptide genes in silkworm cells. Conversely, gene knockdown of BmEts2 significantly enhanced BmRels activity. In addition, two κB sites located on the 5' upstream region of cecropin B1 were found to be involved in the repression of BmRels-mediated promoter activation. Protein-competition analysis further demonstrated that BmEts2 competitively inhibited binding of BmRels to κB sites. Overall, BmEts2 acts as a repressor of BmRels-mediated transactivation of antimicrobial protein genes by inhibiting the binding of BmRels to κB sites.

  14. The TIR Homologue Lies near Resistance Genes in Staphylococcus aureus, Coupling Modulation of Virulence and Antimicrobial Susceptibility

    Science.gov (United States)

    Patot, Sabine; RC Imbert, Paul; Baude, Jessica; Martins Simões, Patricia; Campergue, Jean-Baptiste; Louche, Arthur; Bès, Michèle; Tristan, Anne; Laurent, Frédéric; Fischer, Adrien; Schrenzel, Jacques; François, Patrice; Lina, Gérard

    2017-01-01

    Toll/interleukin-1 receptor (TIR) domains in Toll-like receptors are essential for initiating and propagating the eukaryotic innate immune signaling cascade. Here, we investigate TirS, a Staphylococcus aureus TIR mimic that is part of a novel bacterial invasion mechanism. Its ectopic expression in eukaryotic cells inhibited TLR signaling, downregulating the NF-kB pathway through inhibition of TLR2, TLR4, TLR5, and TLR9. Skin lesions induced by the S. aureus knockout tirS mutant increased in a mouse model compared with wild-type and restored strains even though the tirS-mutant and wild-type strains did not differ in bacterial load. TirS also was associated with lower neutrophil and macrophage activity, confirming a central role in virulence attenuation through local inflammatory responses. TirS invariably localizes within the staphylococcal chromosomal cassettes (SCC) containing the fusC gene for fusidic acid resistance but not always carrying the mecA gene. Of note, sub-inhibitory concentration of fusidic acid increased tirS expression. Epidemiological studies identified no link between this effector and clinical presentation but showed a selective advantage with a SCCmec element with SCC fusC/tirS. Thus, two key traits determining the success and spread of bacterial infections are linked. PMID:28060920

  15. Antimicrobial resistance

    DEFF Research Database (Denmark)

    Llor, Carl; Bjerrum, Lars

    2014-01-01

    is associated with an increased risk of adverse effects, more frequent re-attendance and increased medicalization of self-limiting conditions. Antibiotic overprescribing is a particular problem in primary care, where viruses cause most infections. About 90% of all antibiotic prescriptions are issued by general......-the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid...

  16. Resistance of potential probiotic lactic acid bacteria and bifidobacteria of African and European origin to antimicrobials: Determination and transferability of the resistance genes to other bacteria

    DEFF Research Database (Denmark)

    Ouoba, Labia Irene Ivette; Lei, Vicki; Jensen, Lars Bogø

    2008-01-01

    Probiotic bacteria and starter cultures of Lactobacillus, Weissella and Bifidobacterium of African and European origins were studied and compared for their susceptibility to antimicrobials. The study included, for all isolates, determination of MICs (Minimal Inhibitory Concentration) for 24...

  17. Uses of antimicrobials in plant agriculture.

    Science.gov (United States)

    Vidaver, Anne K

    2002-06-01

    Bacterial diseases of plants are less prevalent than diseases caused by fungi and viruses. Antimicrobials for prophylactic treatment of bacterial diseases of plants are limited in availability, use, and efficacy, and therapeutic use is largely ineffective. Most applications are by spray treatments in orchards. Monitoring and surveillance for drug resistance are not routinely done. In the United States, data on use of antimicrobials for treatment of bacterial diseases of plants are limited to streptomycin and oxytetracycline. Resistance to streptomycin has become widespread among bacterial phytopathogens; no resistance among these bacteria has yet been reported for oxytetracycline. No human health effects have been documented since inception of use of antimicrobials in plants in the 1950s. Transfer of antimicrobial resistance from marker genes in transgenic plants to bacteria has not been documented under natural conditions in field-grown plants. However, antimicrobial-resistance genes are being eliminated from use as marker genes because of concerns about possible transfer from plant genomes back to bacteria, with further horizontal transfer to the bacteria in the environment, or from plant genomes to animals by plant consumption. No new antimicrobials are expected to be used in plant agriculture because of high costs of development, regulatory constraints, and environmental and human health concerns. Alternatives to antimicrobials, such as biocontrol agents, transgenic plants, and novel chemicals, are being developed and marketed, although their efficacy remains to be determined.

  18. The comparison of genotyping, antibiogram, and antimicrobial resistance genes between carbapenem-susceptible and -resistant Acinetobacter baumannii.

    Science.gov (United States)

    Chen, Chih-Ming; Ke, Se-Chin; Li, Chia-Ru; Chang, Chao-Chin

    2014-12-01

    This study was conducted to explore the epidemiological and molecular differences between carbapenem-susceptible Acinetobacter baumannii (CSAB) and carbapenem-resistant A. baumannii (CRAB) isolates. Thirty-two CSAB and 55 CRAB isolates were collected in 2010. By multilocus sequence typing analysis, 31 (56%) CRAB isolates and 11 (34%) CSAB isolates belonged to ST2. Twenty-one (38%) CRAB isolates, and 4 (13%) CSAB isolates belonged to a new type, ST129. The blaIMP, blaVIM, and blaOXA-58-like were not detected in our study isolates. blaOXA-23 and blaOXA-24/40-like were not detected in all CSAB isolates. On the contrary, blaOXA-23 was detected in 51 (93%) CRAB isolates. Class 1 integron was detected in 19 (35%) CRAB isolates and 8 (25%) CSAB isolates (p>0.05). In conclusion, the ST2 and ST129 were the major sequence types in both CSAB and CRAB isolates. The blaOXA-23 is the primary carbapenem-resistance gene in CRAB isolates from hospitalized patients and the specimens collected from hospital environment.

  19. Overexpression of the trichodiene synthase gene tri5 increases trichodermin production and antimicrobial activity in Trichoderma brevicompactum.

    Science.gov (United States)

    Tijerino, Anamariela; Cardoza, R Elena; Moraga, Javier; Malmierca, Mónica G; Vicente, Francisca; Aleu, Josefina; Collado, Isidro G; Gutiérrez, Santiago; Monte, Enrique; Hermosa, Rosa

    2011-03-01

    Trichoderma brevicompactum produces trichodermin, a simple trichothecene-type toxin that shares the first steps of the sesquiterpene biosynthetic pathway with other phytotoxic trichothecenes from Fusarium spp. Trichodiene synthase catalyses the conversion of farnesyl pyrophosphate to trichodiene and it is encoded by the tri5 gene that was cloned and analysed functionally by homologous overexpression in T. brevicompactum. tri5 expression was up-regulated in media with glucose, H(2)O(2) or glycerol. tri5 repression was observed in cultures supplemented with the antioxidants ferulic acid and tyrosol. Acetone extracts of tri5-overexpressing transformants displayed higher antifungal activity than those from the wild-type. Chromatographic and spectroscopic analyses revealed that tri5 overexpression led to an increased production of trichodermin and tyrosol. Agar diffusion assays with these two purified metabolites from the tri5-overexpressing transformant T. brevicompactum Tb41tri5 showed that only trichodermin had antifungal activity against Saccharomyces cerevisiae, Kluyveromyces marxianus, Candida albicans, Candida glabrata, Candida tropicalis and Aspergillus fumigatus, in most cases such activity being higher than that observed for amphotericin B and hygromycin. Our results point to the significant role of tri5 in the production of trichodermin and in the antifungal activity of T. brevicompactum.

  20. Analysis of expression, cellular localization, and function of three inhibitors of apoptosis (IAPs from Litopenaeus vannamei during WSSV infection and in regulation of antimicrobial peptide genes (AMPs.

    Directory of Open Access Journals (Sweden)

    Pei-Hui Wang

    Full Text Available Inhibitors of apoptosis (IAPs play important roles in apoptosis and NF-κB activation. In this study, we cloned and characterized three IAPs (LvIAP1-3 from the Pacific white shrimp, Litopenaeusvannamei. LvIAP1-3 proteins shared signature domains and exhibited significant similarities with other IAP family proteins. The tissue distributions of LvIAP1-3 were studied. The expression of LvIAP1-3 was induced in the muscle after white spot syndrome virus (WSSV infection. LvIAP1 expression in the gill, hemocytes, hepatopancreas, and intestine was responsive to WSSV and Vibrioalginolyticus infections. LvIAP2 expression in the gill, hemocytes, and hepatopancreas was also responsive to WSSV infection. The expression of LvIAP3 in the gill, hemocytes, and intestine was reduced after V. alginolyticus infection. When overexpressed in Drosophila S2 cells, GFP labeled-LvIAP2 was distributed in the cytoplasm and appeared as speck-like aggregates in the nucleus. Both LvIAP1 and LvIAP3 were widely distributed throughout the cytoplasm and nucleus. The expression of LvIAP1, LvIAP2, and LvIAP3 was significantly knocked down by dsRNA-mediated gene silencing. In the gill of LvIAP1- or LvIAP3-silenced shrimp, the expression of WSSV VP28 was significantly higher than that of the dsGFP control group, suggesting that LvIAP1 and LvIAP3 may play protective roles in host defense against WSSV infection. Intriguingly, the LvIAP2-silenced shrimp all died within 48 hours after dsLvIAP2 injection. In the hemocytes of LvIAP2-silenced shrimps, the expression of antimicrobial peptide genes (AMPs, including Penaeidins, lysozyme, crustins, Vibriopenaeicidae-induced cysteine and proline-rich peptides (VICPs, was significantly downregulated, while the expression of anti-lipopolysaccharide factors (ALFs was upregulated. Moreover, LvIAP2 activated the promoters of the NF-κB pathway-controlled AMPs, such as shrimp Penaeidins and Drosophila drosomycin and attacin A, in Drosophila S2 cells

  1. Antimicrobial Resistance in the Food Chain: A Review

    Directory of Open Access Journals (Sweden)

    Lieve Herman

    2013-06-01

    Full Text Available Antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. Antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance traits. Food can be contaminated with antimicrobial resistant bacteria and/or antimicrobial resistance genes in several ways. A first way is the presence of antibiotic resistant bacteria on food selected by the use of antibiotics during agricultural production. A second route is the possible presence of resistance genes in bacteria that are intentionally added during the processing of food (starter cultures, probiotics, bioconserving microorganisms and bacteriophages. A last way is through cross-contamination with antimicrobial resistant bacteria during food processing. Raw food products can be consumed without having undergone prior processing or preservation and therefore hold a substantial risk for transfer of antimicrobial resistance to humans, as the eventually present resistant bacteria are not killed. As a consequence, transfer of antimicrobial resistance genes between bacteria after ingestion by humans may occur. Under minimal processing or preservation treatment conditions, sublethally damaged or stressed cells can be maintained in the food, inducing antimicrobial resistance build-up and enhancing the risk of resistance transfer. Food processes that kill bacteria in food products, decrease the risk of transmission of antimicrobial resistance.

  2. Antimicrobial Resistance in the Food Chain: A Review

    Science.gov (United States)

    Verraes, Claire; Van Boxstael, Sigrid; Van Meervenne, Eva; Van Coillie, Els; Butaye, Patrick; Catry, Boudewijn; de Schaetzen, Marie-Athénaïs; Van Huffel, Xavier; Imberechts, Hein; Dierick, Katelijne; Daube, George; Saegerman, Claude; De Block, Jan; Dewulf, Jeroen; Herman, Lieve

    2013-01-01

    Antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. Antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance traits. Food can be contaminated with antimicrobial resistant bacteria and/or antimicrobial resistance genes in several ways. A first way is the presence of antibiotic resistant bacteria on food selected by the use of antibiotics during agricultural production. A second route is the possible presence of resistance genes in bacteria that are intentionally added during the processing of food (starter cultures, probiotics, bioconserving microorganisms and bacteriophages). A last way is through cross-contamination with antimicrobial resistant bacteria during food processing. Raw food products can be consumed without having undergone prior processing or preservation and therefore hold a substantial risk for transfer of antimicrobial resistance to humans, as the eventually present resistant bacteria are not killed. As a consequence, transfer of antimicrobial resistance genes between bacteria after ingestion by humans may occur. Under minimal processing or preservation treatment conditions, sublethally damaged or stressed cells can be maintained in the food, inducing antimicrobial resistance build-up and enhancing the risk of resistance transfer. Food processes that kill bacteria in food products, decrease the risk of transmission of antimicrobial resistance. PMID:23812024

  3. Antimicrobial resistance in the food chain: a review.

    Science.gov (United States)

    Verraes, Claire; Van Boxstael, Sigrid; Van Meervenne, Eva; Van Coillie, Els; Butaye, Patrick; Catry, Boudewijn; de Schaetzen, Marie-Athénaïs; Van Huffel, Xavier; Imberechts, Hein; Dierick, Katelijne; Daube, George; Saegerman, Claude; De Block, Jan; Dewulf, Jeroen; Herman, Lieve

    2013-06-28

    Antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. Antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance traits. Food can be contaminated with antimicrobial resistant bacteria and/or antimicrobial resistance genes in several ways. A first way is the presence of antibiotic resistant bacteria on food selected by the use of antibiotics during agricultural production. A second route is the possible presence of resistance genes in bacteria that are intentionally added during the processing of food (starter cultures, probiotics, bioconserving microorganisms and bacteriophages). A last way is through cross-contamination with antimicrobial resistant bacteria during food processing. Raw food products can be consumed without having undergone prior processing or preservation and therefore hold a substantial risk for transfer of antimicrobial resistance to humans, as the eventually present resistant bacteria are not killed. As a consequence, transfer of antimicrobial resistance genes between bacteria after ingestion by humans may occur. Under minimal processing or preservation treatment conditions, sublethally damaged or stressed cells can be maintained in the food, inducing antimicrobial resistance build-up and enhancing the risk of resistance transfer. Food processes that kill bacteria in food products, decrease the risk of transmission of antimicrobial resistance.

  4. Determining the optimal number of individual samples to pool for quantification of average herd levels of antimicrobial resistance genes in Danish pig herds using high-throughput qPCR

    DEFF Research Database (Denmark)

    Clasen, Julie; Mellerup, Anders; Olsen, John Elmerdahl

    2016-01-01

    The primary objective of this study was to determine the minimum number of individual fecal samples to pool together in order to obtain a representative sample for herd level quantification of antimicrobial resistance (AMR) genes in a Danish pig herd, using a novel high-throughput qPCR assay....... The secondary objective was to assess the agreement between different methods of sample pooling. Quantification of AMR was achieved using a high-throughput qPCR method to quantify the levels of seven AMR genes (ermB, ermF, sulI, sulII, tet(M), tet(O) and tet(W)). A large variation in the levels of AMR genes...

  5. Molecular cloning and characterization of novel Morus alba germin-like protein gene which encodes for a silkworm gut digestion-resistant antimicrobial protein.

    Directory of Open Access Journals (Sweden)

    Bharat Bhusan Patnaik

    Full Text Available BACKGROUND: Silkworm fecal matter is considered one of the richest sources of antimicrobial and antiviral protein (substances and such economically feasible and eco-friendly proteins acting as secondary metabolites from the insect system can be explored for their practical utility in conferring broad spectrum disease resistance against pathogenic microbial specimens. METHODOLOGY/PRINCIPAL FINDINGS: Silkworm fecal matter extracts prepared in 0.02 M phosphate buffer saline (pH 7.4, at a temperature of 60°C was subjected to 40% saturated ammonium sulphate precipitation and purified by gel-filtration chromatography (GFC. SDS-PAGE under denaturing conditions showed a single band at about 21.5 kDa. The peak fraction, thus obtained by GFC wastested for homogeneityusing C18reverse-phase high performance liquid chromatography (HPLC. The activity of the purified protein was tested against selected Gram +/- bacteria and phytopathogenic Fusarium species with concentration-dependent inhibitionrelationship. The purified bioactive protein was subjected to matrix-assisted laser desorption and ionization-time of flight mass spectrometry (MALDI-TOF-MS and N-terminal sequencing by Edman degradation towards its identification. The N-terminal first 18 amino acid sequence following the predicted signal peptide showed homology to plant germin-like proteins (Glp. In order to characterize the full-length gene sequence in detail, the partial cDNA was cloned and sequenced using degenerate primers, followed by 5'- and 3'-rapid amplification of cDNA ends (RACE-PCR. The full-length cDNA sequence composed of 630 bp encoding 209 amino acids and corresponded to germin-like proteins (Glps involved in plant development and defense. CONCLUSIONS/SIGNIFICANCE: The study reports, characterization of novel Glpbelonging to subfamily 3 from M. alba by the purification of mature active protein from silkworm fecal matter. The N-terminal amino acid sequence of the purified protein was

  6. Evolutionary Pattern of Three Bombyx mori Antimicrobial Peptide Genes Under Influence of Domestication%驯化影响下的家蚕3种抗菌肽基因的进化模式

    Institute of Scientific and Technical Information of China (English)

    郭意; 孙伟; 程静; 沈以红; 张泽; 向仲怀

    2011-01-01

    As innate immune effectors, antimicrobial peptides play crucial roles in the evolution of insect species. In this study, three different antimicrobial peptide genes,DefA,CecE and MorB3, were sequenced from both Bombyx mori and its wild relative, Bombyx mandarina. Polymorphism analyses, neutrality tests, coalescent simulation analyses and linkage disequilibrium analysis to the obtained nucleotide sequences indicated that the three genes were subject to different evolutionary patterns: DefA was a target gene of artificial selection during domestication, CecE was a neutral gene that had undergone domestication bottleneck effect, and the major driven force of MorB3 was genetic drift. Despite of these varied evolutionary patterns, the three genes had higher levels of linkage disequilibrium in domesticated silkworm than those in wild silkworm, indicating that domesticated silkworm had experienced a recent bottleneck effect, and decrease of population size had led to the reduction in gene recombinant rate. Our results provide important information for understanding the evolution and function of different antimicrobial peptides in domesticated silkworm.%抗菌肽作为昆虫的先天性免疫效应因子在昆虫物种进化过程中起着至关重要的作用.测定了家蚕(Bombyx mori)和野桑蚕(Bombyx mandarina)群体的3种不同类型的抗茵肽基因DefA、CecE和MorB3的序列,通过序列核苷酸多态性分析、中性检验、溯祖模拟分析和连锁不平衡分析,发现这3种抗茵肽基因呈现不同的进化模式:DefA属于驯化过程中人工选择的靶基因;CecE是经历了驯化瓶颈效应的中性基因;MorB3的进化受遗传漂变影响.尽管进化模式不同,但家蚕的3种抗菌肽基因连锁不平衡程度均高于野桑蚕,反映家蚕经历了瓶颈效应,群体数量减小导致基因重组率降低.这些结果为理解家蚕不同抗茵肽的进化和功能提供了重要信息.

  7. Antimicrobial resistance of Staphylococcus pseudintermedius.

    Science.gov (United States)

    Kadlec, Kristina; Schwarz, Stefan

    2012-08-01

    Staphylococcus pseudintermedius, Staphylococcus intermedius and Staphylococcus delphini together comprise the S. intermedius group (SIG). Within the SIG, S. pseudintermedius represents the major pathogenic species and is involved in a wide variety of infections, mainly in dogs, but to a lesser degree also in other animal species and humans. Antimicrobial agents are commonly applied to control S. pseudintermedius infections; however, during recent years S. pseudintermedius isolates have been identified that are meticillin-resistant and have also proved to be resistant to most of the antimicrobial agents approved for veterinary applications. This review deals with the genetic basis of antimicrobial resistance properties in S. pseudintermedius and other SIG members. A summary of the known resistance genes and their association with mobile genetic elements is given, as well as an update of the known resistance-mediating mutations. These data show that, in contrast to other staphylococcal species, S. pseudintermedius seems to prefer transposon-borne resistance genes, which are then incorporated into the chromosomal DNA, over plasmid-located resistance genes.

  8. Animation of Antimicrobial Resistance

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    Full Text Available ... Animal & Veterinary Cosmetics Tobacco Products Animal & ... antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development ...

  9. Macrobrachium rosenbergii mannose binding lectin: synthesis of MrMBL-N20 and MrMBL-C16 peptides and their antimicrobial characterization, bioinformatics and relative gene expression analysis.

    Science.gov (United States)

    Arockiaraj, Jesu; Chaurasia, Mukesh Kumar; Kumaresan, Venkatesh; Palanisamy, Rajesh; Harikrishnan, Ramasamy; Pasupuleti, Mukesh; Kasi, Marimuthu

    2015-04-01

    Mannose-binding lectin (MBL), an antimicrobial protein, is an important component of innate immune system which recognizes repetitive sugar groups on the surface of bacteria and viruses leading to activation of the complement system. In this study, we reported a complete molecular characterization of cDNA encoded for MBL from freshwater prawn Macrobrachium rosenbergii (Mr). Two short peptides (MrMBL-N20: (20)AWNTYDYMKREHSLVKPYQG(39) and MrMBL-C16: (307)GGLFYVKHKEQQRKRF(322)) were synthesized from the MrMBL polypeptide. The purity of the MrMBL-N20 (89%) and MrMBL-C16 (93%) peptides were confirmed by MS analysis (MALDI-ToF). The purified peptides were used for further antimicrobial characterization including minimum inhibitory concentration (MIC) assay, kinetics of bactericidal efficiency and analysis of hemolytic capacity. The peptides exhibited antimicrobial activity towards all the Gram-negative bacteria taken for analysis, whereas they showed the activity towards only a few selected Gram-positive bacteria. MrMBL-C16 peptides produced the highest inhibition towards both the Gram-negative and Gram-positive bacteria compared to the MrMBL-N20. Both peptides do not produce any inhibition against Bacillus sps. The kinetics of bactericidal efficiency showed that the peptides drastically reduced the number of surviving bacterial colonies after 24 h incubation. The results of hemolytic activity showed that both peptides produced strong activity at higher concentration. However, MrMBL-C16 peptide produced the highest activity compared to the MrMBL-N20 peptide. Overall, the results indicated that the peptides can be used as bactericidal agents. The MrMBL protein sequence was characterized using various bioinformatics tools including phylogenetic analysis and structure prediction. We also reported the MrMBL gene expression pattern upon viral and bacterial infection in M. rosenbergii gills. It could be concluded that the prawn MBL may be one of the important molecule which

  10. Susceptibility to Infectious Diseases Based on Antimicrobial Peptide Production▿

    Science.gov (United States)

    Rivas-Santiago, Bruno; Serrano, Carmen J.; Enciso-Moreno, J. Antonio

    2009-01-01

    In the last few years, the great impact of antimicrobial peptides on infectious disease susceptibility and natural resistance has been reported. In some cases, susceptibility to diseases is related to antimicrobial peptide polymorphisms and gene copy numbers, but for the vast majority of infectious diseases, these phenomena need to be elucidated. This review is focused on the current knowledge about susceptibility and resistance conferred by genetic variations in antimicrobial peptide expression in infectious diseases. PMID:19703980

  11. Susceptibility to infectious diseases based on antimicrobial peptide production.

    Science.gov (United States)

    Rivas-Santiago, Bruno; Serrano, Carmen J; Enciso-Moreno, J Antonio

    2009-11-01

    In the last few years, the great impact of antimicrobial peptides on infectious disease susceptibility and natural resistance has been reported. In some cases, susceptibility to diseases is related to antimicrobial peptide polymorphisms and gene copy numbers, but for the vast majority of infectious diseases, these phenomena need to be elucidated. This review is focused on the current knowledge about susceptibility and resistance conferred by genetic variations in antimicrobial peptide expression in infectious diseases.

  12. Polymyxins resistance: old antimicrobials, last therapeutic options

    Directory of Open Access Journals (Sweden)

    Raquel Girardello

    2012-07-01

    Full Text Available Polymyxins are polypeptide antimicrobials that act in the cell membranes and promote decrease of the cell wall integrity. These antimicrobials are used in the clinical practice for treatment of the multi-drug resistant Gram negative bacilli infections as the last therapeutic option. The polymyxin resistance involves lipopolysaccharide modifi cations that decrease the affi nity of the antimicrobial with the cell surface. These modifi cations are regulated by two component systems that are active by environmental infl uences as cation presence, pH or polymyxin exposure. The environmental infl uences initiate the action of the genes that develop the polymyxins resistant phenotype. The polymyxins viability maintenance is essential for the treatment for multi-drug resistant bacilli infections, while new therapeutic options are not available.KEYWORDS polimixins antimicrobial resistance

  13. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Gottlieb, Caroline Trebbien; Vestergaard, Martin;

    2015-01-01

    antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around...... the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl2 concentrations......-encoded natural tolerance mechanisms included peptide cleavage and the addition of positive charge to the cell surface, both of which minimized the antimicrobial activity of FL9. Our results add new information about FL9 and its effect on S. aureus, which may aid in the future development of analogues...

  14. Anti-antimicrobial Peptides

    Science.gov (United States)

    Ryan, Lloyd; Lamarre, Baptiste; Diu, Ting; Ravi, Jascindra; Judge, Peter J.; Temple, Adam; Carr, Matthew; Cerasoli, Eleonora; Su, Bo; Jenkinson, Howard F.; Martyna, Glenn; Crain, Jason; Watts, Anthony; Ryadnov, Maxim G.

    2013-01-01

    Antimicrobial or host defense peptides are innate immune regulators found in all multicellular organisms. Many of them fold into membrane-bound α-helices and function by causing cell wall disruption in microorganisms. Herein we probe the possibility and functional implications of antimicrobial antagonism mediated by complementary coiled-coil interactions between antimicrobial peptides and de novo designed antagonists: anti-antimicrobial peptides. Using sequences from native helical families such as cathelicidins, cecropins, and magainins we demonstrate that designed antagonists can co-fold with antimicrobial peptides into functionally inert helical oligomers. The properties and function of the resulting assemblies were studied in solution, membrane environments, and in bacterial culture by a combination of chiroptical and solid-state NMR spectroscopies, microscopy, bioassays, and molecular dynamics simulations. The findings offer a molecular rationale for anti-antimicrobial responses with potential implications for antimicrobial resistance. PMID:23737519

  15. [Antimicrobial prophylaxis in surgery].

    Science.gov (United States)

    Cisneros, José Miguel; Rodríguez-Baño, Jesús; Mensa, José; Trilla, Antoni; Cainzos, Miguel

    2002-01-01

    Antimicrobial prophylaxis in surgery refers to a very brief course of an antimicrobial agent initiated just before the start of the procedure. The efficacy of antimicrobials to prevent postoperative infection at the site of surgery (incisional superficial, incisional deep, or organ/space infection) has been demonstrated for many surgical procedures. Nevertheless, the majority of studies centering on the quality of preoperative prophylaxis have found that a high percentage of the antimicrobials used are inappropriate for this purpose. This work discusses the scientific basis for antimicrobial prophylaxis, provides general recommendations for its correct use and specific recommendations for various types of surgery. The guidelines for surgical antimicrobial prophylaxis are based on results from well-designed studies, whenever possible. These guidelines are focussed on reducing the incidence of infection at the surgical site while minimizing the contribution of preoperative administration of antimicrobials to the development of bacterial resistance.

  16. Regulation of antimicrobial resistance by extracytoplasmic function (ECF) sigma factors.

    Science.gov (United States)

    Woods, Emily C; McBride, Shonna M

    2017-01-30

    Extracytoplasmic function (ECF) sigma factors are a subfamily of σ(70) sigma factors that activate genes involved in stress-response functions. In many bacteria, ECF sigma factors regulate resistance to antimicrobial compounds. This review will summarize the ECF sigma factors that regulate antimicrobial resistance in model organisms and clinically relevant pathogens.

  17. Salmon aquaculture and antimicrobial resistance in the marine environment.

    Science.gov (United States)

    Buschmann, Alejandro H; Tomova, Alexandra; López, Alejandra; Maldonado, Miguel A; Henríquez, Luis A; Ivanova, Larisa; Moy, Fred; Godfrey, Henry P; Cabello, Felipe C

    2012-01-01

    Antimicrobials used in salmon aquaculture pass into the marine environment. This could have negative impacts on marine environmental biodiversity, and on terrestrial animal and human health as a result of selection for bacteria containing antimicrobial resistance genes. We therefore measured the numbers of culturable bacteria and antimicrobial-resistant bacteria in marine sediments in the Calbuco Archipelago, Chile, over 12-month period at a salmon aquaculture site approximately 20 m from a salmon farm and at a control site 8 km distant without observable aquaculture activities. Three antimicrobials extensively used in Chilean salmon aquaculture (oxytetracycline, oxolinic acid, and florfenicol) were studied. Although none of these antimicrobials was detected in sediments from either site, traces of flumequine, a fluoroquinolone antimicrobial also widely used in Chile, were present in sediments from both sites during this period. There were significant increases in bacterial numbers and antimicrobial-resistant fractions to oxytetracycline, oxolinic acid, and florfenicol in sediments from the aquaculture site compared to those from the control site. Interestingly, there were similar numbers of presumably plasmid-mediated resistance genes for oxytetracycline, oxolinic acid and florfenicol in unselected marine bacteria isolated from both aquaculture and control sites. These preliminary findings in one location may suggest that the current use of large amounts of antimicrobials in Chilean aquaculture has the potential to select for antimicrobial-resistant bacteria in marine sediments.

  18. Human health risks associated with antimicrobial-resistant enterococci and Staphylococcus aureus on poultry meat

    DEFF Research Database (Denmark)

    Bortolaia, V.; Gongora, Carmen Espinosa; Guardabassi, L.

    2016-01-01

    and national reports on prevalence, bacterial load, antimicrobial resistance and clonal distribution of these three species on poultry meat. The risks associated with ingestion of antimicrobial-resistant enterococci of poultry origin comprise horizontal transfer of resistance genes and transmission...... interest to the human gut microbiota. Ingestion of poultry meat contaminated with S. aureus may lead to food poisoning. However, antimicrobial resistance in the toxin -producing strains does not have clinical implications because food poisoning is not managed by antimicrobial therapy. Recently methicillin...

  19. Aquaculture as yet another environmental gateway to the development and globalisation of antimicrobial resistance.

    Science.gov (United States)

    Cabello, Felipe C; Godfrey, Henry P; Buschmann, Alejandro H; Dölz, Humberto J

    2016-07-01

    Aquaculture uses hundreds of tonnes of antimicrobials annually to prevent and treat bacterial infection. The passage of these antimicrobials into the aquatic environment selects for resistant bacteria and resistance genes and stimulates bacterial mutation, recombination, and horizontal gene transfer. The potential bridging of aquatic and human pathogen resistomes leads to emergence of new antimicrobial-resistant bacteria and global dissemination of them and their antimicrobial resistance genes into animal and human populations. Efforts to prevent antimicrobial overuse in aquaculture must include education of all stakeholders about its detrimental effects on the health of fish, human beings, and the aquatic ecosystem (the notion of One Health), and encouragement of environmentally friendly measures of disease prevention, including vaccines, probiotics, and bacteriophages. Adoption of these measures is a crucial supplement to efforts dealing with antimicrobial resistance by developing new therapeutic agents, if headway is to be made against the increasing problem of antimicrobial resistance in human and veterinary medicine.

  20. Human Health Consequences of Use of Antimicrobial Agents in Aquaculture

    DEFF Research Database (Denmark)

    Heuer, Ole Eske; Kruse, H.; Grave, K.

    2009-01-01

    industry in many regions of the world and the widespread, intensive, and often unregulated use of antimicrobial agents in this area of animal production, efforts are needed to prevent development and spread of antimicrobial resistance in aquaculture to reduce the risk to human health.......Intensive use of antimicrobial agents in aquaculture provides a selective pressure creating reservoirs of drug-resistant bacteria and transferable resistance genes in fish pathogens and other bacteria in the aquatic environment. From these reservoirs, resistance genes may disseminate by horizontal...... gene transfer and reach human pathogens, or drug-resistant pathogens from the aquatic environment may reach humans directly. Horizontal gene transfer may occur in the aquaculture environment, in the food chain, or in the human intestinal tract. Among the antimicrobial agents commonly used...

  1. Antimicrobials in beekeeping.

    Science.gov (United States)

    Reybroeck, Wim; Daeseleire, Els; De Brabander, Hubert F; Herman, Lieve

    2012-07-06

    The bee diseases American and European foulbrood and nosemosis can be treated with anti-infectious agents. However, in the EU and the USA the use of these agents in beekeeping is strictly regulated due to the lack of tolerance (e.g. Maximum Residue Limit) for residues of antibiotics and chemotherapeutics in honey. This article reviews the literature dealing with antimicrobials of interest in apiculture, stability of these antimicrobials in honey, and disposition of the antimicrobials in honeybee hives.

  2. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Resistance National Antimicrobial Resistance Monitoring System 2014 NARMS ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  3. Animation of Antimicrobial Resistance

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    Full Text Available ... more understandable to non-scientists by showing how bacterial antimicrobial resistance can develop and spread. All FDA CVM ... Education Inspections & Compliance Federal, State & Local ...

  4. Animation of Antimicrobial Resistance

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    Full Text Available ... CVM produced material may be copied, reproduced, and distributed as long as FDA's Center for Veterinary Medicine ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  5. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  6. ANTIMICROBIAL HERBAL DRUGS

    Directory of Open Access Journals (Sweden)

    K. Nishteswar

    2011-12-01

    Full Text Available An anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes (microbiocidal or prevent the growth of microbes (microbiostatic. Sulphonamide drugs were the first antimicrobial drugs, and paved the way for the antibiotic revolution in medicine. The first sulfonamide, trade named Prontosil, was actually a prodrug. However, with the development of antimicrobials, microorganisms have adapted and become resistant to previous antimicrobial agents. In view of certain side effects caused due to usage of modern antimicrobial drugs and antibiotics scientists have made some attempts to screen some of the Ayurvedic herbs, which possess broader spectrum of safety. Some selected herbs which are used by tribal and rural people for curing various infective diseases caused due to bacteria, virus and fungi have been reported to possess anti-microbial properties. In the present paper and attempt is made to review about the indigenous medicinal plant which exhibited antimicrobial properties.

  7. Animation of Antimicrobial Resistance

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    Full Text Available ... Skip to common links HHS U.S. Department of Health and Human Services U.S. Food and Drug Administration ... Tobacco Products Animal & Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet ...

  8. Antimicrobial peptides in crustaceans

    Directory of Open Access Journals (Sweden)

    RD Rosa

    2010-11-01

    Full Text Available Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP families are currently recognized, although the great majority (14 families comes from members of the order Decapoda. Crustacean AMPs are generally cationic, gene-encoded molecules that are mainly produced by circulating immune-competent cells (hemocytes or are derived from unrelated proteins primarily involved in other biological functions. In this review, we tentatively classified the crustacean AMPs into four main groups based on their amino acid composition, structural features and multi-functionality. We also attempted to summarize the current knowledge on their implication both in an efficient response to microbial infections and in crustacean survival.

  9. Antimicrobial peptides in annelids

    Directory of Open Access Journals (Sweden)

    A Tasiemski

    2008-06-01

    Full Text Available Gene encoded antimicrobial peptides (AMPs are widely distributed among living organisms including plants, invertebrates and vertebrates. They constitute important effectors of the innate immune response by exerting multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis and immune induction. In invertebrates, most of the data describe the characterization and/or the function of AMPs in the numerically and economically most representative group which are arthropods. Annelids are among the first coelomates and are therefore of special phylogenetic interest. Compared to other invertebrate groups, data on annelid’s immunity reveal heavier emphasis on the cellular than on the humoral response suggesting that immune defense of annelids seems to be principally developed as cellular immunity.This paper gives an overview of the variety of AMPs identified in the three classes of annelids, i.e. polychaetes, oligochaetes and achaetes. Their functions, when they have been studied, in the humoral or cellular response of annelids are also mentioned.

  10. Alternative Antimicrobial Approach: Nano-Antimicrobial Materials

    Directory of Open Access Journals (Sweden)

    Nurit Beyth

    2015-01-01

    Full Text Available Despite numerous existing potent antibiotics and other antimicrobial means, bacterial infections are still a major cause of morbidity and mortality. Moreover, the need to develop additional bactericidal means has significantly increased due to the growing concern regarding multidrug-resistant bacterial strains and biofilm associated infections. Consequently, attention has been especially devoted to new and emerging nanoparticle-based materials in the field of antimicrobial chemotherapy. The present review discusses the activities of nanoparticles as an antimicrobial means, their mode of action, nanoparticle effect on drug-resistant bacteria, and the risks attendant on their use as antibacterial agents. Factors contributing to nanoparticle performance in the clinical setting, their unique properties, and mechanism of action as antibacterial agents are discussed in detail.

  11. Antimicrobial prophylaxis in adults.

    Science.gov (United States)

    Enzler, Mark J; Berbari, Elie; Osmon, Douglas R

    2011-07-01

    Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement, and bite wounds. Perioperative antimicrobial prophylaxis is recommended for various surgical procedures to prevent surgical site infections. Optimal antimicrobial agents for prophylaxis should be bactericidal, nontoxic, inexpensive, and active against the typical pathogens that can cause surgical site infection postoperatively. To maximize its effectiveness, intravenous perioperative prophylaxis should be administered within 30 to 60 minutes before the surgical incision. Antimicrobial prophylaxis should be of short duration to decrease toxicity and antimicrobial resistance and to reduce cost.

  12. Antimicrobial resistance profile analysis of MRSE with psm-mec gene%携带 psm-mec 基因耐甲氧西林表皮葡萄球菌的耐药谱研究

    Institute of Scientific and Technical Information of China (English)

    杨永长; 肖代雯; 喻华; 姜伟; 陈亮; 胡洪华; 周薇; 黄文芳

    2015-01-01

    目的:比较携带与未携带psm-mec基因耐甲氧西林表皮葡萄球菌( MRSE)的耐药谱,为治疗MRSE引起的感染提供理论依据。方法收集临床分离并经过全自动微生物奠定系统准确鉴定的表皮葡萄球菌( Staphylococcus epidermidis,S. epidermidis)165株,通过PCR扩增esp和mecA基因,准确鉴定和区分甲氧西林敏感表皮葡萄球菌( MSSE)和MRSE。扩增psm-mec,fudoh和p221片段确认携带psm-mec基因的MRSE菌株,比较分析携带与未携带psm-mec 基因MRSE的耐药谱。结果83.64%的临床分离S.epidermidis为MRSE,其中29株携带psm-mec基因,携带率为17.58%,且仅分布于MRSE中。临床分离MRSE易对苯唑西林、青霉素、红霉素、复方新诺明和克林霉素耐药,未发现对利奈唑胺、呋喃妥因、普丁/达福、万古霉素和替加环素耐药菌株。携带psm-mec基因MRSE对环丙沙星、庆大霉素、利福平和复方新诺明的耐药率明显高于未携带psm-mec基因MRSE。结论携带psm-mec基因MRSE易对苯唑西林、青霉素、红霉素、克林霉素、环丙沙星、庆大霉素、利福平和复方新诺明耐药。%Objective To compare the antimicrobial resistance profiles between MRSE with and without psm-mec gene in or-der to provide foundation for treatment of MRSE infection disease.Methods One hundred and sixty five strains of S.epidermidis iden-tified accurately by full automation microbiological identification system were collected.PCR was used to amplify esp and mecA gene to differentiate methicillin-resistant S.epidermidis ( MRSE) and methicillin-sensitive S.epidermidis ( MSSE) .Strains with psm-mec gene were validated by amplification of psm-mec,fudoh and p221 fragments,and antimicrobial resistance profile of MRSE with or without psm-mec gene was analyzed.Results MRSE accounted for 83.64%of clinical isolated S.epidermidis,and 29 strains were positive for psm-mec gene with a rate of 17.58%,which were

  13. Fast disinfecting antimicrobial surfaces.

    Science.gov (United States)

    Madkour, Ahmad E; Dabkowski, Jeffery M; Nusslein, Klaus; Tew, Gregory N

    2009-01-20

    Silicon wafers and glass surfaces were functionalized with facially amphiphilic antimicrobial copolymers using the "grafting from" technique. Surface-initiated atom transfer radical polymerization (ATRP) was used to grow poly(butylmethacrylate)-co-poly(Boc-aminoethyl methacrylate) from the surfaces. Upon Boc-deprotection, these surfaces became highly antimicrobial and killed S. aureus and E. coli 100% in less than 5 min. The molecular weight and grafting density of the polymer were controlled by varying the polymerization time and initiator surface density. Antimicrobial studies showed that the killing efficiency of these surfaces was independent of polymer layer thickness or grafting density within the range of surfaces studied.

  14. Novel antimicrobial textiles

    Science.gov (United States)

    Cho, Unchin

    2003-10-01

    Many microorganisms can survive, and perhaps proliferate on textiles, generating adverse effects such as: disease transmission, odor generation, pH changes, staining, discoloration and loss of performance. These adverse effects may threaten users' health, deteriorate textile properties and degrade service quality. It may, therefore, be desirable to incorporate antimicrobials on textiles for controlling the growth of microorganisms. This dissertation focuses on the development of antimicrobial fibers and fabrics by integration of antimicrobials with these textiles. The applications of hydantoin-based halamines were mainly investigated in the research. The typical process is that hydantoin containing compounds are grafted onto textiles and transformed to halamine by chlorination. Hydantoin-based halamines are usually chloramines that release chlorine (Cl+) via cleavage of the -NCl functional group which attacks and kills microbes. The antimicrobial behavior is rechargeable many times by rinsing the fiber or fabric with chlorine-containing solution. Some quaternary ammonium type antimicrobials were also investigated in this research. The choice of integrating techniques is dependant on both the textile and antimicrobial compounds. In this dissertation, the nine approaches were studied for incorporating antimicrobial with various textiles: (1) co-extrusion of fibers with halamine precursor additive; (2) grafting of the quaternary ammonium compounds onto ethylene-co-acrylic acid fiber for creating quaternary ammonium type antimicrobial fiber; (3) entrapment of the additives in thermally bonded bicomponent nonwoven fabrics; (4) attaching antimicrobial additives to surfaces with latex adhesive coating; (5) grafting of antimicrobial compounds onto rubber latex via UV exposure; (6) reaction of halamine with needle-punched melamine formaldehyde nonwoven fabric and laminates; (7) coating melamine resin onto tent fabrics and laminates; (8) synthesis of super absorbent polymer

  15. Antimicrobial compounds in tears.

    Science.gov (United States)

    McDermott, Alison M

    2013-12-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here.

  16. DNA microarray genotyping and virulence and antimicrobial resistance gene profiling of methicillin-resistant Staphylococcus aureus bloodstream isolates from renal patients.

    LENUS (Irish Health Repository)

    McNicholas, Sinead

    2012-02-01

    Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.

  17. DNA microarray genotyping and virulence and antimicrobial resistance gene profiling of methicillin-resistant Staphylococcus aureus bloodstream isolates from renal patients.

    LENUS (Irish Health Repository)

    McNicholas, Sinead

    2011-12-01

    Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29\\/36 (80%) and 33\\/36 (92%) isolates, respectively.

  18. -Genomic data mining of the marine actinobacteria Streptomyces sp. H-KF8 unveils insights into multi-stress related genes and metabolic pathways involved in antimicrobial synthesis.

    Science.gov (United States)

    Undabarrena, Agustina; Ugalde, Juan A; Seeger, Michael; Cámara, Beatriz

    2017-01-01

    Streptomyces sp. H-KF8 is an actinobacterial strain isolated from marine sediments of a Chilean Patagonian fjord. Morphological characterization together with antibacterial activity was assessed in various culture media, revealing a carbon-source dependent activity mainly against Gram-positive bacteria (S. aureus and L. monocytogenes). Genome mining of this antibacterial-producing bacterium revealed the presence of 26 biosynthetic gene clusters (BGCs) for secondary metabolites, where among them, 81% have low similarities with known BGCs. In addition, a genomic search in Streptomyces sp. H-KF8 unveiled the presence of a wide variety of genetic determinants related to heavy metal resistance (49 genes), oxidative stress (69 genes) and antibiotic resistance (97 genes). This study revealed that the marine-derived Streptomyces sp. H-KF8 bacterium has the capability to tolerate a diverse set of heavy metals such as copper, cobalt, mercury, chromate and nickel; as well as the highly toxic tellurite, a feature first time described for Streptomyces. In addition, Streptomyces sp. H-KF8 possesses a major resistance towards oxidative stress, in comparison to the soil reference strain Streptomyces violaceoruber A3(2). Moreover, Streptomyces sp. H-KF8 showed resistance to 88% of the antibiotics tested, indicating overall, a strong response to several abiotic stressors. The combination of these biological traits confirms the metabolic versatility of Streptomyces sp. H-KF8, a genetically well-prepared microorganism with the ability to confront the dynamics of the fjord-unique marine environment.

  19. Antimicrobial susceptibility and Ribosomal-RNA gene restriction patterns among Staphylococcus-intermedius from healthy dogs and from dogs sufferning from pyoderma or otitis-externa

    DEFF Research Database (Denmark)

    Pedersen, Karl; Wegener, Henrik Caspar

    1995-01-01

    A total of 60 Staphlococcus intermedius strains from dogs were investigated by their sensitivity to various antibiotics (50 strains) and by their rRNA gene restriction patterns (ribotyping) (60 strains). Fifteen isolates were from healthy dogs, 9 with otitis externa, and 36 with pyoderma, includi...

  20. Comparison of individual and pooled samples for quantification of antimicrobial resistance genes in swine feces by high-throughput qPCR

    DEFF Research Database (Denmark)

    Clasen, Julie; Mellerup, Anders; Olsen, John Elmerdahl

    2015-01-01

    samples were taken from each pen with respect to the number of pigs in the pen. A total of 48 pools were made of increasing number of individual samples. The levels of 9 different AMR-genes were quantified using dynamic qPCR arrays on the BioMark HD system(Fluidigm®).DNA was extracted using the Maxwell...

  1. Antimicrobial Susceptibility and Distribution of TEM and CTX-M Genes among ESBL-producing Klebsiella pneumoniae and Pseudomonas aeruginosa Causing Urinary Tract Infections

    Directory of Open Access Journals (Sweden)

    Roya Alavi-Naini

    2014-04-01

    Full Text Available Background: Extended spectrum beta lactamases (ESBLs have been observed in nearly all the species of family Enterobacteriaceae. The enzymes are plasmid mediated and are derived from broad-spectrum beta lactamase TEM and CTX- M by a limited number of mutations. This study was undertaken to characterize ESBL producers among Klebsiella pneumoniae and Pseudomonas aeruginosa by PCR, which were initially screened by phenotypic method. Materials and Methods: A cross-sectional study was performed to evaluate 180 strains (30 K. pneumoniae and 150 P. aeruginosa isolated from urine culture of hospitalized patients (Amir Al-Momenin Hospital, Zabol, south-eastern Iran suffered from urinary tract infections during a period of six months. The prevalence of ESBL producing K. pneumoniae and P. aeruginosa was evaluated by disk diffusion test and polymerase chain reaction (PCR by detecting TEM and CTX-M gene. Results: The results of the study revealed that the prevalence of ESBL producing P. aeruginosa and K. pneumoniae by disk diffusion test was 13.3% for P. aeruginosa and 66.6% for K. pneumoniae. Seventy five percent and 65% of K. pneumoniae harboured the gene TEM and CTX-M, respectively. Forty five percent of P. aeruginosa isolates harboured the gene TEM but none of them demonstrated the gene CTX-M using PCR method. Conclusion: ESBL producing P. aeruginosa and K. pneumoniae isolates showed a high prevalence in this study. Therefore it seems that continuous surveillance is essential to monitor the ESBLs producing microorganisms in hospitals and community

  2. Evaluation of feeding distiller's grains, containing virginiamycin, on antimicrobial susceptibilities in fecal isolates of Enterococcus and Escherichia coli and prevalence of resistance genes in cattle

    Science.gov (United States)

    Dried distiller’s grains (DG), produced from fermentations using no antibiotic (Control) or dosed with 2 or 20 ppm virginiamycin product and containing 0, 0.7, and 8.9 ppm virginiamycin, respectively, were fed to cattle and effects on antibiotic sensitivity and prevalence of resistance genes in comm...

  3. Construction of Eukaryotic Expression Vector with Rana Antimicrobial Peptides Gene Temporin-lCEa%中国林蛙抗菌肽Temporin-1CEa基因的真核表达载体构建。

    Institute of Scientific and Technical Information of China (English)

    张志崇; 王春生; 张秋婷; 朴善花; 苗向阳; 安铁洙

    2012-01-01

    In order to establish a method to get a large number of antimicrobial peptides from Rana chensinensis,a series of experiments were conducted as follows.According to Chinese frog skin antimicrobial peptides Temporin-1CEa gene mRNA sequence(EU624139) in GenBank,a pair of specific primers were designed and cDNA was obtained from Chinese forest frog skin RNA by reverse transcription.Temporin-1CEa gene coding sequence was amplified using the cDNA,and linked with pEASY-T3 cloning vector.The GFP gene was inserted into the recombinant plasmid Tem-T3 by molecular methods.The Tem-GFP fragment was linked with eukaryotic expression vector pcDNA3.1,and Tem-GFP-pcDNA3.1 recombinant plasmid was achieved finally.Using of lipid infection method,the plasmids were transfected into sheep fibroblast cells,the green fluorescence was observed under a fluorescence microscope after 48 h.qPCR data showed that Tem-GFP fusion protein expression level of transfected Tem-GFP-pcDNA3.1 sheep fibroblasts increased about 300 folds than that of the control group.This study supplied the technical basis for developing mammary gland bioreactor of expressing Temporin-1CEa gene.%为了建立大量获取中国林蛙抗菌肽的方法,根据GenBank中的中国林蛙皮肤抗菌肽Temporin-1CEa基因的mRNA序列(EU624139)设计一对特异性引物,以提取的中国林蛙皮肤总RNA反转录出的cDNA为模板,将扩增的编码序列与pEASY-T3克隆载体连接获得Tem-T3;利用酶切、连接等分子生物学手段,将GFP基因连入Tem-T3克隆载体,再经酶切获得Tem-GFP片段,并插入真核表达载体pcDNA3.1,最终得到Tem-GFP-pcD-NA3.1重组质粒;利用脂质体转染法将该质粒转入绵羊成纤维细胞,48 h后可在荧光倒置显微镜下观察到GFP的绿色荧光表达;qPCR数据分析显示,与对照组相比,转染Tem-GFP-pcDNA3.1的绵羊成纤维细胞中融合蛋白Tem-GFP的表达量可提高约300倍。本研究为构建Temporin-1CEa基因山羊乳腺特异表达载体提供依据。

  4. Influence of the yjiL-mdtM Gene Cluster on the Antibacterial Activity of Proline-Rich Antimicrobial Peptides Overcoming Escherichia coli Resistance Induced by the Missing SbmA Transporter System.

    Science.gov (United States)

    Krizsan, Andor; Knappe, Daniel; Hoffmann, Ralf

    2015-10-01

    In view of increasing health threats from multiresistant pathogens, antimicrobial peptides (AMPs) and, specifically, proline-rich AMPs (PrAMPs) have been investigated in animal models. PrAMPs enter bacteria via the ABC transporter SbmA and inhibit intracellular targets. We used phage transduction (Tn10 insertion) to screen by random mutagenesis for alternative uptake mechanisms for analogs of apidaecin 1b, a honeybee-derived PrAMP. All 24 apidaecin-resistant mutants had the Tn10 insertion in the sbmA gene. These sbmA::Tn10 insertion mutants and the Escherichia coli BW25113 ΔsbmA (JW0368) strain were still susceptible to the bactenecin PrAMP Bac7(1-35) and oncocin PrAMPs Onc18 and Onc112, as well as to Chex1-Arg20, despite significantly reduced internalizations. In a second round of random mutagenesis, the remaining susceptibility was linked to the yjiL-mdtM gene cluster. E. coli BW25113 and its ΔyjiL null mutant (JW5785) were equally susceptible to all PrAMPs tested, whereas the BW25113 ΔmdtM mutant was less susceptible to oncocins. The JW0368 yjiL::Tn10 transposon mutant (BS2) was resistant to all short PrAMPs and susceptible only to full-length Bac7 and A3-APO. Interestingly, PrAMPs appear to enter bacteria via MdtM, a multidrug resistance transporter (drug/H(+) antiporter) of the major facilitator superfamily (MFS) that can efflux antibiotics, biocides, and bile salts. In conclusion, PrAMPs enter bacteria via ABC and MFS transporters that efflux antibiotics and cytotoxic compounds from the cytoplasm to the periplasm.

  5. The prevalence of antimicrobial resistance and carriage of virulence genes in Staphylococcus aureus isolated from food handlers in Kuwait City restaurants

    Directory of Open Access Journals (Sweden)

    Al-Mufti Siham

    2009-06-01

    Full Text Available Abstract Background Staphylococcus aureus is a major cause of food poisoning due to their ability to produce enterotoxins which if ingested in sufficient amounts results in sickness. Food handlers carrying enterotoxin-producing S. aureus in their noses or hands can contaminate food leading to food poisoning. We characterized 200 S. aureus obtained from food handlers in different restaurants for antibacterial resistance and the carriage of virulence genes. Findings Susceptibility to antibacterial agents was determined by disk diffusion and Etest. PCR was used to detect genes for accessory gene regulator (agr; capsular polysaccharide (cap 5 and 8, staphylococcal enterotoxins (SE, toxic shock syndrome toxin-1 (TSST-1 and Panton-Valentine leukocidin (PVL. Isolates were typed using pulsed-field gel electrophoresis. In total 185 (92.5% of the 200 isolates expressed resistance to antibacterial agents. They were resistant to penicillin G (82.0%, tetracycline (19.0%, erythromycin (2.5%, clindamycin (2.0%, trimethoprim (7.5%, kanamycin (2.5%, streptomycin (1.5%, ciprofloxacin (1.5%, fusidic acid (1.0% and cadmium acetate (68.0%. Seventy-six (38.0% and 114 (57.0% isolates had type 5 and type 8 capsular polysaccharides respectively. The agr types I, II and III alleles were detected in 50.5%, 20.0% and 23.5% of the isolates respectively. They contained genes for SEI (38.5%, SEG (24.0%, SEC (23.0%, SEB (12.5%, SEH (21.5%, SEA (11.0, SED (1.5%, SEE (1.5%, TSST-1 (4.0% and PVL (9.0%. Conclusion This study revealed a high prevalence of antibacterial resistance and virulence determinants in S. aureus from food handlers in Kuwait restaurants justifying the screening of food handlers to detect and treat carriers and protect restaurant customers from staphylococcal food poisoning.

  6. Antimicrobial activity and the presence of virulence factors and bacteriocin structural genes in Enterococcus faecium CM33 isolated from ewe colostrum.

    Science.gov (United States)

    Nami, Yousef; Haghshenas, Babak; Haghshenas, Minoo; Yari Khosroushahi, Ahmad

    2015-01-01

    Screening of lactic acid bacteria (LAB) isolated from ewe colostrum led to the identification and isolation of Enterococcus faecium CM33 with interesting features like high survival rates under acidic or bile salts condition, high tolerance for the simulated gastrointestinal condition, and high adhesive potential to Caco-2 cells. According the inhibition of pathogen adhesion test results, this strain can reduce more than 50% adhesion capacity of Escherichia coli, Shigella flexneri, Klebsiella pneumoniae, Listeria monocytogenes, and Staphylococcus aureus to Caco-2 cells. Based on the antibiotic sensitivity test findings, E. faecium CM33 was susceptible to gentamycin, vancomycin, erythromycin, ampicillin, penicillin, tetracycline, and rifampicin, but resistant to chloramphenicol, clindamycin, and kanamycin. Upon assessment of the virulence determinants for E. faecium CM33, this strain was negative for all tested virulence genes. Furthermore, the genome of this strain was evaluated for the incidence of the known enterocin genes by specific PCR amplification and discovered the genes encoding enterocins A, 31, X, and Q. Based on this study findings, the strain E. faecium CM33 can be considered as a valuable nutraceutical and can be introduced as a new potential probiotic.

  7. Antimicrobial activity and the presence of virulence factors and bacteriocin structural genes in Enterococcus faecium CM33 isolated from ewe colostrum

    Directory of Open Access Journals (Sweden)

    YOUSEF eNAMI

    2015-07-01

    Full Text Available AbstractScreening of lactic acid bacteria isolated from ewe colostrum led to the identification and isolation of Enterococcus faecium CM33 with interesting features, such as high-survival rates under acidic or bile salt conditions, high tolerance to the simulated gastrointestinal condition, and high adhesive potential to Caco-2 cells. According to the inhibition of pathogen adhesion test results, this strain could reduce more than 50% adhesion capacity of Escherichia coli, Shigella flexneri, Klebsiella pneumoniae, Listeria monocytogenes, and Staphylococcus aureus to Caco-2 cells. Based on the antibiotic sensitivity test findings, E. faecium CM33 was susceptible to gentamycin, vancomycin, erythromycin, ampicillin, penicillin, tetracycline, and rifampicin, but resistant to chloramphenicol, clindamycin, and kanamycin. Upon the assessment of the virulence determinants for E. faecium CM33, this strain was negative for all tested virulence genes. Furthermore, the genome of this strain was evaluated for the incidence of the known enterocin genes by specific PCR amplification, and the genes encoding enterocins A, 31, X, and Q were discovered. The findings of this study showed that the strain E. faecium CM33 could be considered a valuable nutraceutical, and it can be introduced as a new potential probiotic.

  8. Functional divergence among silkworm antimicrobial peptide paralogs by the activities of recombinant proteins and the induced expression profiles.

    Directory of Open Access Journals (Sweden)

    Wanying Yang

    Full Text Available Antimicrobial peptides are small-molecule proteins that are usually encoded by multiple-gene families. They play crucial roles in the innate immune response, but reports on the functional divergence of antimicrobial peptide gene families are rare. In this study, 14 paralogs of antimicrobial peptides belonging to cecropin, moricin and gloverin families were recombinantly expressed in pET expression systems. By antimicrobial activity tests, peptides representing paralogs in the same family of cecropin and moricin families, displayed remarkable differences against 10 tested bacteria. The evolutionary rates were relatively fast in the two families, which presented obvious functional divergence among paralogs of each family. Four peptides of gloverin family had similar antimicrobial spectrum and activity against tested bacteria. The gloverin family showed similar antimicrobial function and slow evolutionary rates. By induced transcriptional activity, genes encoding active antimicrobial peptides were upregulated at obviously different levels when silkworm pupae were infected by three types of microbes. Association analysis of antimicrobial activities and induced transcriptional activities indicated that the antimicrobial activities might be positively correlated with induced transcriptional activities in the cecropin and moricin families. These results suggest that representative BmcecB6, BmcecD and Bmmor as the major effector genes have broad antimicrobial spectrum, strong antimicrobial activity and high microbe-induced expression among each family and maybe play crucial roles in eliminating microbial infection.

  9. Construction of Eukaryotic Expression Vector and Sequence Analysis of Antimicrobial Peptide Gene Shiva 1a%抗菌肽Shiva1a基因真核表达载体的构建及序列分析

    Institute of Scientific and Technical Information of China (English)

    宫晓炜; 郑福英; 蔺国珍; 曹小安; 王光华; 周继章; 才学鹏

    2011-01-01

    为了探讨天蚕类抗菌肽在动物早期抗感染过程中的作用机理,本研究以Shiva 1a基因的成熟肽为模板设计4条引物,利用重叠延伸PCR技术获得目的基因,并在C端添加6×His的标签.将此序列与真核表达载体pIRES2 -EGFP进行重组,构建pIRES2-EGFP-Shiva 1a重组表达质粒,对重组质粒进行酶切和测序鉴定后,采用阳离子脂质体转染将重组质粒转染到CHO-K1细胞,荧光显微镜观察其表达情况.通过生物信息学软件对抗菌肽Shiva 1a的二级结构和三级结构进行预测分析.其结果为进一步研究Shiva 1a的抗菌活性和在动物抗病育种方面的应用奠定了基础.%To explore the effect mechanism of cecropin-class lytic peptide at early stage of infection. The mat peptide of Shiva la was amplified by overlap extension PCR and the C-terminus contained 6×His-marker. The gene sequence were recombi-nant with eukaryotic expression vector pIRES2-EGFP. After being identified by restriction enzyme digestion and sequencing, the recombinant plasmid pIRES2-EGFP-Shiva la was transfected into CHO-K1 cells by liposomes. The expression of the the recombinant plasmid pIRES2-EGFP-Shiva 1a was observed by fluorescence microscope. At the same time, the secondary structure and 3D structure were predicted by bioinformatics tools. The results lay the foundation in research of antimicrobial activities and applications of the antimicrobial peptide Shiva la in breeding for disease resistance of animals.

  10. Antimicrobials, stress and mutagenesis.

    Directory of Open Access Journals (Sweden)

    Alexandro Rodríguez-Rojas

    2014-10-01

    Full Text Available Cationic antimicrobial peptides are ancient and ubiquitous immune effectors that multicellular organisms use to kill and police microbes whereas antibiotics are mostly employed by microorganisms. As antimicrobial peptides (AMPs mostly target the cell wall, a microbial 'Achilles heel', it has been proposed that bacterial resistance evolution is very unlikely and hence AMPs are ancient 'weapons' of multicellular organisms. Here we provide a new hypothesis to explain the widespread distribution of AMPs amongst multicellular organism. Studying five antimicrobial peptides from vertebrates and insects, we show, using a classic Luria-Delbrück fluctuation assay, that cationic antimicrobial peptides (AMPs do not increase bacterial mutation rates. Moreover, using rtPCR and disc diffusion assays we find that AMPs do not elicit SOS or rpoS bacterial stress pathways. This is in contrast to the main classes of antibiotics that elevate mutagenesis via eliciting the SOS and rpoS pathways. The notion of the 'Achilles heel' has been challenged by experimental selection for AMP-resistance, but our findings offer a new perspective on the evolutionary success of AMPs. Employing AMPs seems advantageous for multicellular organisms, as it does not fuel the adaptation of bacteria to their immune defenses. This has important consequences for our understanding of host-microbe interactions, the evolution of innate immune defenses, and also sheds new light on antimicrobial resistance evolution and the use of AMPs as drugs.

  11. Antimicrobial Resistant Streptococcus pneumoniae

    Directory of Open Access Journals (Sweden)

    B Khanal

    2010-09-01

    Full Text Available Introduction: Pneumococcal infections are important cause of morbidity and mortality. Knowledge of antimicrobial susceptibility patterns plays important role in the selection of appropriate therapy. Present study was undertaken to analyze the susceptibility patterns of pneumococcal isolates against commonly used antimicrobials with special reference to determination of minimum inhibitory concentration (MIC of penicillin in a tertiary care hospital in eastern Nepal. Methods: Twenty-six strains of S. pneumoniae isolated from various clinical specimens submitted to microbiology laboratory were evaluated. All isolates were tested for antimicrobial susceptibility by disk diffusion method. MIC of penicillin was tested by broth dilution method. Results: Of the total isolates 19 (73% were from invasive infections. Seven isolates were resistant to cotrimoxazole. No resistance to penicillin was seen in disk diffusion testing. Less susceptibility to penicillin (MIC 0.1-1.0 mg/L was observed in five (17% isolates. High level resistance to penicillin was not detected. One isolate was multidrug resistant. Conclusions: S. pneumoniaeisolates with intermediate resistance to penicillin prevail in Tertiary Care Hospital in eastern Nepal, causing invasive and noninvasive infections. As intermediate resistance is not detected in routine susceptibility testing, determination of MIC is important. It helps not only in the effective management of life threatening infections but is also essential in continuous monitoring and early detection of resistance. In addition, further study on pneumococcal infections, its antimicrobial resistance profile and correlation with clinical and epidemiological features including serotypes and group prevalence is recommended in future. Keywords: antimicrobial susceptibility pattern, penicillin, Streptococcus pneumoniae.

  12. General principles of antimicrobial therapy.

    Science.gov (United States)

    Leekha, Surbhi; Terrell, Christine L; Edson, Randall S

    2011-02-01

    Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community.

  13. Antimicrobial stewardship: Limits for implementation

    NARCIS (Netherlands)

    Sinha, Bhanu

    2014-01-01

    Antibiotic stewardship programme (ASP) is a multifaceted approach to improve patients' clinical outcomes, prevent the emergence of antimicrobial resistance, and reduce hospital costs by prudent and focused antimicrobial use. Development of local treatment guidelines according to local ecology, rapid

  14. Salmonella enterica in imported and domestic day-old turkey poults in Egypt: repertoire of virulence genes and their antimicrobial resistance profiles.

    Science.gov (United States)

    Osman, K M; Marouf, S H; Erfan, A M; AlAtfeehy, N

    2014-12-01

    Globalisation and international trade facilitate the rapid spread and transmission of foodborne pathogens. This study was designed to determine the serovars, distribution of virulence genes (invA, avrA, ssaQ, mgtC, siiD, sopB, gipA, sodC1, sopE1, spvC, bcfC) and antibiotic resistance profiles in salmonellae recovered from imported and domestic day-old turkey poults in Egypt. The prevalence of salmonellae in the imported poults was 4% (6/150): S. Enteritidis was the most frequent isolate (1.3%; 2/150), followed by Typhimurium, Virchow, Larochelle and a non-typeable strain, each with 0.7% (1/150) prevalence. The prevalence of salmonellae in the domestic poults was < 2% (2/150) and serotyping indicated a prevalence of 1.3% (1/150) for both Typhimurium and Altona. In polymerase chain reaction screening, the genes invA, sopB and bcfC were detected in all the Enteritidis, Typhimurium, Virchow, Larochelle, Altona and non-typeable isolates (100%); the gene gipA was absent from all isolates. Carriage of invA, sopB and bcfC among the Enteritidis, Typhimurium, Virchow, Larochelle, Altona and non-typeable isolates was associated with a core pattern of resistance to three antibiotics: streptomycin, nalidixic acid and chloramphenicol. The detection of S. Enteritidis, Typhimurium, Virchow, Larochelle, and Altona in turkey poults has important implications because these serovars are a significant cause of foodborne illness and enteric fever in humans.

  15. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  16. Genome-wide identification of antimicrobial intrinsic resistance determinants in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Martin Vestergaard

    2016-12-01

    Full Text Available The emergence of antimicrobial resistance severely threatens our ability to treat bacterial infections. While acquired resistance has received considerable attention, relatively little is known of intrinsic resistance that allows bacteria to naturally withstand antimicrobials. Gene products that confer intrinsic resistance to antimicrobial agents may be explored for alternative antimicrobial therapies, by potentiating the efficacy of existing antimicrobials. In this study, we identified the intrinsic resistome to a broad spectrum of antimicrobials in the human pathogen, Staphylococcus aureus. We screened the Nebraska Transposon Mutant Library of 1920 single-gene inactivations in S. aureus strain JE2, for increased susceptibility to the anti-staphylococcal antimicrobials (ciprofloxacin, oxacillin, linezolid, fosfomycin, daptomycin, mupirocin, vancomycin and gentamicin. 68 mutants were confirmed by E-test to display at least two-fold increased susceptibility to one or more antimicrobial agents. The majority of the identified genes have not previously been associated with antimicrobial susceptibility in S. aureus. For example, inactivation of genes encoding for subunits of the ATP synthase, atpA, atpB, atpG and atpH, reduced the minimum inhibitory concentration (MIC of gentamicin 16-fold. To elucidate the potential of the screen, we examined treatment efficacy in the Galleria mellonella infection model. Gentamicin efficacy was significantly improved, when treating larvae infected with the atpA mutant compared to wild type cells with gentamicin at a clinically relevant concentration. Our results demonstrate that many gene products contribute to the intrinsic antimicrobial resistance of S. aureus. Knowledge of these intrinsic resistance determinants provides alternative targets for compounds that may potentiate the efficacy of existing antimicrobial agents against this important pathogen.

  17. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    of antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which...

  18. Antimicrobial Prophylaxis in Adults

    OpenAIRE

    Enzler, Mark J.; Berbari, Elie; Osmon, Douglas R.

    2011-01-01

    Antimicrobial prophylaxis is commonly used by clinicians for the prevention of numerous infectious diseases, including herpes simplex infection, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, infective endocarditis, pertussis, and acute necrotizing pancreatitis, as well as infections associated with open fractures, recent prosthetic joint placement...

  19. Triclosan antimicrobial polymers

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2016-03-01

    Full Text Available Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers

  20. Triclosan antimicrobial polymers

    Science.gov (United States)

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers that set on cooling

  1. Human Health Hazards from Antimicrobial-Resistant Escherichia coli of Animal Origin

    DEFF Research Database (Denmark)

    Hammerum, A. M.; Heuer, Ole Eske

    2009-01-01

    Because of the intensive use of antimicrobial agents in food animal production, meat is frequently contaminated with antimicrobial-resistant Escherichia coli. Humans can be colonized with E. coli of animal origin, and because of resistance to commonly used antimicrobial agents, these bacteria may...... cause infections for which limited therapeutic options are available. This may lead to treatment failure and can have serious consequences for the patient. Furthermore, E. coli of animal origin may act as a donor of antimicrobial resistance genes for other pathogenic E. coli. Thus, the intensive use...

  2. Antimicrobial peptides in Echinoderms

    Directory of Open Access Journals (Sweden)

    C Li

    2010-05-01

    Full Text Available Antimicrobial peptides (AMPs are important immune effector molecules for invertebrates, including echinoderms, which lack a vertebrate-type adaptive immune system. Here we summarize the knowledge of such peptides in echinoderms. Strongylocins are a novel family of cysteine-rich AMPs, recently identified in the sea urchins, Strongylocentrotus droebachiensis and S. purpuratus. Although these molecules present diverse amino acid sequences, they share an identical cysteine arrangement pattern, dissimilar to other known AMPs. A family of heterodimeric AMPs, named centrocins, are also present in S. droebachiensis. Lysozymes and fragments of larger proteins, such as beta-thymocins, actin, histone 2A and filamin A have also been shown to display antimicrobial activities in echinoderms. Future studies on AMPs should be aimed in revealing how echinoderms use these AMPs in the immune response against microbial pathogens.

  3. Combating antimicrobial resistance: antimicrobial stewardship program in Taiwan.

    Science.gov (United States)

    Tseng, Shu-Hui; Lee, Chun-Ming; Lin, Tzou-Yien; Chang, Shan-Chwen; Chuang, Yin-Ching; Yen, Muh-Yong; Hwang, Kao-Pin; Leu, Hsieh-Shong; Yen, Che-Chieh; Chang, Feng-Yee

    2012-04-01

    Multi-drug-resistant organisms are increasingly recognized as a global public health issue. Healthcare-associated infection and antimicrobial resistance are also current challenges to the treatment of infectious diseases in Taiwan. Government health policies and the health care systems play a crucial role in determining the efficacy of interventions to contain antimicrobial resistance. National commitment to understand and address the problem is prerequisite. We analyzed and reviewed the antibiotic resistance related policies in Taiwan, USA, WHO and draft antimicrobial stewardship program to control effectively antibiotic resistance and spreading in Taiwan. Antimicrobial stewardship program in Taiwan includes establishment of national inter-sectoral antimicrobial stewardship task force, implementing antimicrobial-resistance management strategies, surveillance of HAI and antimicrobial resistance, conducting hospital infection control, enforcement of appropriate regulations and audit of antimicrobial use through hospital accreditation, inspection and national health insurance payment system. No action today, no cure tomorrow. Taiwan CDC would take a multifaceted, evidence-based approach and make every effort to combat antimicrobial resistance with stakeholders to limit the spread of multi-drug resistant strains and to reduce the generation of antibiotic resistant bacteria in Taiwan.

  4. Triclosan antimicrobial polymers

    OpenAIRE

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are ...

  5. Antimicrobial Peptides in Echinoderms

    OpenAIRE

    Li, C; Haug, T; K Stensvåg

    2010-01-01

    Antimicrobial peptides (AMPs) are important immune effector molecules for invertebrates, including echinoderms, which lack a vertebrate-type adaptive immune system. Here we summarize the knowledge of such peptides in echinoderms. Strongylocins are a novel family of cysteine-rich AMPs, recently identified in the sea urchins, Strongylocentrotus droebachiensis and S. purpuratus. Although these molecules present diverse amino acid sequences, they share an identical cysteine arrangement pattern, d...

  6. [Neruda and antimicrobial resistance].

    Science.gov (United States)

    Cotera, Alejandro

    2011-07-01

    Antimicrobial resistance has been a problem in medicine, since their incorporation to clinical practice. Numerous papers have been written on the subject. The analysis of two poems by Pablo Neruda "How much does a man live" and "Larynx", included in the volume "Estravagario" and published for the first time in 1957 and 1958, give us an incredible revelation about the concept of resistance. In these poems aureomycin, the first antimicrobial of the family of tetracyclines, was included as a poetic figure and the therapeutic action of antimicrobials was described. "Never so much bugs died I tons of them fell I but the few that remained olive I manifested their perversity". These writings incorporated novel concepts, even for physicians of that time and described the closeness of death that a patient may perceive during the course of a given disease. The capacity of Pablo Neruda to extract the essence of situations and to anticipate to conditions that only years later became clinically relevant problems, is noteworthy.

  7. [Antimicrobial mechanisms of action].

    Science.gov (United States)

    Calvo, Jorge; Martínez-Martínez, Luis

    2009-01-01

    A large number of families and groups of antimicrobial agents are of clinical interest. The mechanisms by which compounds with antibacterial activity inhibit growth or cause bacterial death are varied and depend on the affected targets. The bacterial cell wall-a unique structure in most bacteria that is absent in eukaryotic cells-can be affected in several ways: at different stages of synthesis (fosfomycin, cycloserine) or transport (bacitracin, mureidomycins) of its metabolic precursors, or by a direct action on its structural organization (beta-lactams, glycopeptides). The main drugs affecting the cytoplasmic membrane are polymyxins and daptomycin. Protein synthesis can be blocked by a large variety of compounds that affect any of the phases of this process, including activation (mupirocin), initiation (oxazolidinones, aminoglycosides), binding of the tRNA amino acid complex to ribosomes (tetracyclines, glycylcyclines) and elongation (amphenicols, lincosamides, macrolides, ketolides, streptogramins, fusidic acid). The metabolism of nucleic acids can be altered at the DNA-dependent RNA polymerase or in the process of DNA coiling (quinolones); some compounds affect DNA directly (nitroimidazoles, nitrofurans). Trimethoprim and sulfamides (often used in combination) are examples of antimicrobial agents that block bacterial metabolic pathways. Some compounds are unable to inhibit or kill bacteria in themselves, but can block bacterial mechanisms of resistance, enhancing the activity of other antimicrobials administered in combination. Among this group of agents, only certain beta-lactamase inhibitors are currently in clinical use.

  8. Human neutrophil antimicrobial activity.

    Science.gov (United States)

    Thomas, E L; Lehrer, R I; Rest, R F

    1988-01-01

    Polymorphonuclear neutrophilic leukocytes (PMNs) take up opsonized microorganisms into phagosomes that fuse with secretory granules in the PMN cytoplasm to form phagolysosomes. Killing and digestion of microorganisms take place within phagolysosomes. Antimicrobial activities in phagolysosomes are divided into two classes. Oxygen (O2)-dependent mechanisms are expressed when PMNs undergo the "respiratory burst." An NADPH oxidase in the phagolysosome membrane is activated and reduces O2 to superoxide (O2-). O2 reduction is the first step in a series of reactions that produce toxic oxidants. For example, .O2- dismutases to hydrogen peroxide (H2O2), and the azurophil granule enzyme myeloperoxidase catalyzes the oxidation of Cl- by H2O2 to yield hypochlorous acid (HOCl). The reaction of HOCl with ammonia and amines modulates the toxicity of this oxidant. O2-independent antimicrobial mechanisms include the activities of lysosomal proteases, other hydrolytic enzymes, and proteins and peptides that bind to microorganisms and disrupt essential processes or structural components. For example, the bactericidal/permeability-increasing protein, cathepsin G, and the defensins are released into phagolysosomes from the azurophil granules. Proposed mechanisms of action of neutrophil antimicrobial agents, their range of microbial targets, and their possible interactions within phagolysosomes are discussed.

  9. Human health hazard from antimicrobial-resistant enterococci in animals and food

    DEFF Research Database (Denmark)

    Heuer, Ole Eske; Hammerum, Anette Marie; Collignon, P.

    2006-01-01

    The use of antimicrobial agents in the modern farm industry has created a reservoir of resistant bacteria in food animals. Foods of animal origin are often contaminated with enterococci that are likely to contribute resistance genes, virulence factors, or other properties to enterococci IN humans....... The potential hazard to human health from antimicrobial-resistant enterococci in animals is questioned by some scientists because of evidence of host specificity of enterococci. Similarly, the occurrences of specific nosocomial clones of enterococci in hospitals have lead to the misconception that antimicrobial...... to change the current view that antimicrobial-resistant enterococci from animals pose a threat to human health. On the contrary, antimicrobial resistance genes appear to spread freely between enterococci from different reservoirs, irrespective of their apparent host association....

  10. Gene

    Data.gov (United States)

    U.S. Department of Health & Human Services — Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes,...

  11. Antimicrobial Drugs in the Home

    Centers for Disease Control (CDC) Podcasts

    2006-10-19

    Survey participants in the United Kingdom admitted keeping leftover antimicrobial drugs for future use and taking them without medical advice. Dr. J. Todd Weber, director of CDC's Office of Antimicrobial Resistance, advises against the practice, which can be dangerous and can promote antimicrobial drug resistance.  Created: 10/19/2006 by Emerging Infectious Diseases.   Date Released: 10/26/2006.

  12. Analysis of the Antimicrobial-Resistant Gene and Virulence Gene Carried by Staphylococcus Aureus Collected from Bloodstream Infections in Tianjin:2006-2011%2006-2011年60株血感染金黄色葡萄球菌毒素及耐药基因分析

    Institute of Scientific and Technical Information of China (English)

    王立新; 胡神明; 胡志东; 田彬; 李静; 王凤霞; 杨华

    2013-01-01

    Objective To investigate resistance profile, antimicrobial-resistant genes and virulence genes carried by 60 staphylococcus aureus collected from bloodstream infections in General Hospital of Tianjin Medical University from 2006 to 2011.Methods The bacteria identification and the antimicrobial susceptibility test were conducted by VITEK-2 compact automatic system.Methicillin resistant staphylococcus aureus (MRSA) were screened by disk diffusion method with cefoxitin.The polymerase chain reaction (PCR)was used to detect genes of mecA, qacA, pvl, sea, seb, secI, sed, see and TSST-1.Results The resistance rates of 60 isolates to penicillin, erythromycin, clindamycin and gentamicin were 91.7%, 65.0%, 65.0% and 40.0%, respectively.All of the isolates were susceptible to vancomycin, linezolid, and tigecycline.Among the 60 isolates, the positive rates of mecA and qacA werel3 (21.7%) and 3(5.0%) respectively.The positive rates of pvl, sea, seb,sec and sed were 4 (6.7%),20(33.3%), 3 (5%),9 (15.0%) and 7 (11.7%).Both see and tst were negative in all strains.Conclusion The resistance rates of staphylococcus aureus collected from bloodstream infections were high to penicillin , erythromycin, clindamycin and gentamicin.The various toxin and the antimicrobial-resistant genes were positive in staphylococcus aureus.We should pay attention to the detection of the antimicrobial-resistant gene and virulence gene.%目的 了解2006-2011年临床分离的60株血感染金黄色葡萄球菌的耐药情况及毒素基因和耐药基因的流行情况.方法 VITEK 2-compact全自动细菌鉴定仪及配套鉴定卡、药敏卡对细菌进行鉴定及药敏试验;头孢西丁纸片扩散法筛选耐甲氧西林金黄色葡萄球菌(MRSA);应用聚合酶链反应(PCR)检测mecA、耐消毒剂基因(qacA)、杀白细胞素基因(pvl)、肠毒素基因(sea、seb、secl、sed、see)及中毒休克综合征毒素-1基因(tst).结果 60株金黄色葡萄球菌

  13. Antimicrobial resistance among enterococci from pigs in three European countries

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Hasman, Henrik; Jensen, Lars Bogø;

    2002-01-01

    Enterococci from pigs in Denmark, Spain, and Sweden were examined for susceptibility to antimicrobial agents and copper and the presence of selected resistance genes. The greatest levels of resistance were found among isolates from Spain and Denmark compared to those from Sweden, which correspond...

  14. 直链烷基苯磺酸钠对中国林蛙抗菌肽基因表达的影响%The Effects of Linear Alkylbenzene Sulfonate on Antimicrobial Peptide Genes Expression in Rana chensinensis

    Institute of Scientific and Technical Information of China (English)

    谢晖; 孙燕; 李治; 宋婧

    2011-01-01

    近年来由于生境丧失及环境污染等原因,中国林蛙野生种群急剧减少.为深入研究水体中普遍存在的阴离子表面活性剂直链烷基苯磺酸钠(linear alkylbenzene sulfonate,LAS)对中国林蛙生存的影响,通过急毒实验确定LAS对分别处于发育阶段26、32、42、46期的中国林蛙的半致死浓度.同时利用1、4、8 mg/L LAS处理不同发育阶段中国林蛙,研究LAS对中国林蛙存活率、发育状态的影响,并利用real-time PCR技术检测中国林蛙抗菌肽基因表达水平变化.结果表明,当处理时间为96 h,LAS浓度达到12.33 mg/L以上时会对不同发育阶段中国林蛙产生较为严重的致死效应.1~8 mg/L浓度范围的LAS虽然对中国林蛙存活和发育没有明显影响,但是改变了其抗菌肽基因表达模式.特别是中国林蛙胚后发育后期(32期)和变态期(42期),4~8 mg/L LAS会在不同程度上抑制prepropalustrin-2CE3 、preprobrevinin-2CE1和preprotemporin-1 CEd1抗菌肽基因表达.总体而言,高浓度LAS对中国林蛙免疫系统造成一定影响,可能使该物种更易受到致病菌的侵袭.研究结果为化学污染物对中国林蛙免疫系统影响积累了实验数据,同时为研究中国林蛙抗菌肽基因表达的调控通路提供一定的理论依据.%Rana chensinensis has been suffered from a dramatic reduction in recent years due to the losing of habitat, environmental pollution and so on. To understand the influence of linear alkylbenzene sulfonate (LAS), which is one of the most important pollutants in water environment, on the survival of Rana chensinensis, the median lethal concentration of LAS had been calculated by explosion of the frogs at stage 26, 32, 42, 46 in different concentrations of LAS. The effects of 1, 4, 8 mg/L LAS on the survival and development of Rana chensinensis at different stages were also investigated. Also, the expressions of antimicrobial peptide genes were detected by real-time PCR. The

  15. Absorbent silver (I) antimicrobial fabrics

    Science.gov (United States)

    In recent years, silver in form of silver ions, has been gaining importance in the wound management as an effective broad-spectrum antimicrobial agent. Silver has a long history as an antimicrobial agent, especially in the treatment of wounds. Alginates and carboxymethyl (CM) cotton contain carboxyl...

  16. Antimicrobial stewardship: philosophy versus practice.

    Science.gov (United States)

    Dodds Ashley, Elizabeth S; Kaye, Keith S; DePestel, Daryl D; Hermsen, Elizabeth D

    2014-10-15

    To promote the judicious use of antimicrobials and preserve their usefulness in the setting of growing resistance, a number of policy-making bodies and professional societies have advocated the development of antimicrobial stewardship programs. Although these programs have been implemented at many institutions in the United States, their impact has been difficult to measure. Current recommendations advocate the use of both outcome and process measures as metrics for antimicrobial stewardship. Although patient outcome metrics have the greatest impact on the quality of care, the literature shows that antimicrobial use and costs are the indicators measured most frequently by institutions to justify the effectiveness of antimicrobial stewardship programs. The measurement of more meaningful outcomes has been constrained by difficulties inherent to these measures, lack of funding and resources, and inadequate study designs. Antimicrobial stewardship can be made more credible by refocusing the antimicrobial review process to target specific disease states, reassessing the usefulness of current metrics, and integrating antimicrobial stewardship program initiatives into institutional quality and safety efforts.

  17. How to fight antimicrobial resistance.

    Science.gov (United States)

    Foucault, Cédric; Brouqui, Philippe

    2007-03-01

    Antimicrobial misuse results in the development of resistance and superbugs. Over recent decades, resistance has been increasing despite continuing efforts to control it, resulting in increased mortality and cost. Many authorities have proposed local, regional and national guidelines to fight against this phenomenon, and the usefulness of these programmes has been evaluated. Multifaceted intervention seems to be the most efficient method to control antimicrobial resistance. Monitoring of bacterial resistance and antibiotic use is essential, and the methodology has now been homogenized. The implementation of guidelines and infection control measures does not control antimicrobial resistance and needs to be reinforced by associated measures. Educational programmes and rotation policies have not been evaluated sufficiently in the literature. Combination antimicrobial therapy is inefficient in controlling antimicrobial resistance.

  18. Antimicrobial screening of Mnium stellare

    Directory of Open Access Journals (Sweden)

    Kerem Canli

    2015-06-01

    Full Text Available Many plants contain active substances that are known to be effective in both enhancing the wound healing process and lowering the incidence of wound infections. Previous studies have shown that bryophytes produce a variety of secondary metabolites that present pharmaceutical activities including antimicrobial activity against various pathogenic bacteria and fungi. The aim of this study was to investigate the antimicrobial activity of Mnium stellare against 17 bacterial and 1 fungal strains. Our present study has shown that the ethanol extract of M. stellare has antimicrobial activity against several Gram positive and Gram negative microorganism tested, but its antimicrobial activity is notable especially against B. subtilis, S. typhimirium, S. aureus, S. carnosus, and S. epidermidis. These results are the very first report of the antimicrobial activity of M. stellare.

  19. Antimicrobial resistance of bacterial strains isolated from avian cellulitis

    Directory of Open Access Journals (Sweden)

    MM Santos

    2014-03-01

    Full Text Available Avian cellulitis is an inflammatory process in the subcutaneous tissue, mainly located in the abdomen and thighs. This problem is commonly observed in poultry at slaughter and it is considered one of the major causes of condemnation of carcasses in Brazil. The aim of this study was to perform the microbial isolation of lesions of avian cellulitis from a processing plant located in the State of Goiás in order to analyze antimicrobial resistance by antibiogram test and to detect resistance genes by polymerase chain reaction. A total of 25 samples of avian cellulitis lesions were analyzed, from which 30 bacterial strains were isolated. There were eleven (44% strains of Escherichia coli, nine (36% strains of Staphylococcus epidermidis, seven (28% strains of Proteus mirabilis and three (12% strains of Manheimiahaemolytica. The antibiogram test showed that all strains were resistant to at least one antimicrobial. The gene of antimicrobial resistance tetB was detected in E. coli, S. epidermidis and P. mirabilis strains, and was the most frequently observed gene. The gene of antimicrobial resistance Sul1 was detected in all bacterial species, while tetA was found in E. coli and S. epidermidis strains, SHV in E. coli strains, S. epidermidis and P. mirabilis,and cat1 in one P. mirabilis strain. The results suggest a potential public health hazard due to the ability of these microorganisms to transmit antimicrobial resistancegenes to other microorganisms present in the intestinal tract of humans and animals, which may affect clinical-medical usage of these drugs.

  20. 48株流感嗜血杆菌耐药性分析及β-内酰胺酶基因检测%Analysis on antimicrobial resistance and beta-lactamases gene detection of 48 haemophilus influenzae

    Institute of Scientific and Technical Information of China (English)

    桂和翠; 王中新; 沈继录

    2012-01-01

    目的 了解本地区流感嗜血杆菌的分布及耐药性,为指导临床合理用药提供依据.方法 k-B法进行药敏试验,玻片法测定β-内酰胺酶.PCR扩增TEM及ROB型β-内酰胺酶基因.结果 48株流感嗜血杆菌主要分布于呼吸内科和门诊.对复方新诺明、四环素和氨苄西林耐药率分别为62.50%、35.42% 和22 92%;阿莫西林/克拉维酸钾、氨曲南耐药率为12.50%;氨苄西林/舒巴坦、头孢噻肟、头孢拉定、头孢曲松、阿奇霉素、氯霉素耐药率为8.33%;头孢吡肟、头孢呋辛、环丙沙星、左氧氟沙星耐药率为6.25%.哌拉西林/三唑巴坦、亚胺培南敏感率高为100%.10株氨苄西林耐药菌株均产β-内酰胺酶,产酶率为20.83%,且均检测到TEM基因.结论 复方新诺明和四环素已不再适于临床治疗流感嗜血杆菌引起的感染.氨苄西林仍可作为临床经验用药.哌拉西林/三唑巴坦和亚胺培南抗菌活性高,可望作为治疗耐氨苄西林流感嗜血杆菌感染的理想用药.喹诺酮类药物耐药率高,应引起重视.流感嗜血杆菌对氨苄西林耐药的主要机制为产TEM型β-内酰胺酶.%To investigate antimicrobial resistance and genotypes of β-lactamase of in this erea , and guide clinical rational drug use effectively. Methods Kirby-Bauer method was applied for the drug susceptibility test and nitrocefin slide test was used to detect β-lactamase. The genotypes of β-lactamase were detected by PCR. Results A total of 48 strains of haemophilus influenzae were mainly distributed in department of respiratory and outpatient service. The resistant straint to compound sulf-amethoxazole, ampicillin and tetrocycline were 62. 50% , 35. 42% ,22. 92% respectively, the resistant rate to amoxicillin-clavulanic acid, ceftriaxome, aztreonam, ciprofloxa-cin and levofloxacin was 12.50% ,the resistant rate to ampicillin-sulbactam, cefotaxime, ceftazidime, cefuroxime, azithromycin, chlorampheniol was 8. 33% ;the

  1. Perfil de sensibilidade antimicrobiana e detecção do gene ISS pela reação em cadeia da polimerase na tipificação de Escherichia coli patogênica em codornas de corte sob inspeção sanitária Profile of antimicrobial resistance and detection of iss gene by the polymerase chain reaction in the typification of pathogenic Escherichia coli in meat type quails under sanitary inspection

    Directory of Open Access Journals (Sweden)

    Dayse Lima da Costa Abreu

    2010-05-01

    Full Text Available A patogenicidade das cepas de Escherichia coli está relacionada à expressão de fatores de virulência encontrados em elementos genéticos denominados plasmídios. O patotipo APEC, responsável por diferentes tipos de doenças em aves, pode apresentar o gene iss que aumenta a resistência das cepas de E. coli aos efeitos líticos do soro, além da resistência a diversos antimicrobianos. Este estudo foi conduzido para detectar E. coli em traquéias de codornas destinadas ao abate e avaliar, pela presença do gene iss e o perfil de susceptibilidade antimicrobiana, o potencial patogênico para aves e humanos dos isolados obtidos. Foram coletadas 180 traquéias de codornas para detecção de E. coli, determinação do perfil de resistência a agentes antimicrobianos e posterior detecção, por reação em cadeia da polimerase (PCR, do gene iss. Das traquéias analisadas, 8,9 % (16/180 foram positivas para E. coli, sendo obtidos 20 isolados deste agente. A maioria dos isolados foi resistente à Tetraciclina (16/20, seguida pela Ceftazidima (13/20 e Ácido Nalidíxico (12/20, sendo apenas um resistente à Amoxicilina. A detecção do gene iss ocorreu em 55% (11/20 dos isolados. A presença do gene iss e a resistência a múltiplos antimicrobianos dos isolados obtidos neste estudo pode indicar um possível potencial patogênico das cepas de E. coli tanto para codornas quanto para outros tipos de aves e animais e mesmo para o ser humano que fique em contato com as mesmas.The pathogenicity of Escherichia coli strains is partially related to the expression of virulence factors genes, present in genetic elements called plasmids. APEC strains responsible for diseases in birds may present the iss gene which increases the resistance of E. coli strains to the lityc effect of the host's serum, besides resistance to several antimicrobials. This study was conduced in order to detect E. coli in tracheae of meat-type quails and to evaluate, by the presence of

  2. Novel Formulations for Antimicrobial Peptides

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    Ana Maria Carmona-Ribeiro

    2014-10-01

    Full Text Available Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.

  3. [Antimicrobial susceptibility in Chile 2012].

    Science.gov (United States)

    Cifuentes-D, Marcela; Silva, Francisco; García, Patricia; Bello, Helia; Briceño, Isabel; Calvo-A, Mario; Labarca, Jaime

    2014-04-01

    Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.

  4. Antimicrobial resistance of thermophilic Campylobacter

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Engberg, J.

    2001-01-01

    Campylobacter has become the leading cause of zoonotic enteric infections in developed and developing countries world-wide. Antimicrobial resistance has emerged among Campylobacter mainly as a consequence of the use of antimicrobial agents in food animal production. Resistance to drugs of choice...... for the treatment of infections, macrolides and fluoroquinolones has emerged as a clinical problem and interventions to reduce this are recommended. Resistance to fluoroquinolones and macrolides is mediated by chromosomal mutations. Resistance to other relevant antimicrobial agents, mediated by acquired resistance...

  5. Antimicrobial properties of hemoglobin.

    Science.gov (United States)

    Sheshadri, Preethi; Abraham, Jayanthi

    2012-12-01

    Hemoglobin consists of a heme containing component and a globin unit. It exists as a tetramer with 2 α subunits and 2 β subunits in adults and with 2 α subunits and 2 γ chains in infants. On proteolytic cleavage, hemoglobin breaks down to produce many biologically active compounds, among which are hemocidins, those which exhibit antimicrobial property. The generation of these peptides does not depend on the blood group, Rhesus factor, age and sex of the healthy donors. The microbicidal activity has been observed against a variety of gram positive and Gram-negative bacteria, and against filamentous fungi, yeast and even certain parasites. The discovery of hemocidins opens a new field for research into the details of the peptides acting as second line of defence in boosting the innate immune system of the organisms.

  6. Association between the consumption of antimicrobial agents in animal husbandry and the occurrence of resistant bacteria among food animals

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller

    1999-01-01

    Antimicrobial agents are used in food animals for therapy and prophylaxis of bacterial infections and in feed to promote growth. The use of antimicrobial agents for food animals may cause problems in the therapy of infections by selecting for resistance among bacteria pathogenic for animals...... animals, the quantitative impact of the use of different antimicrobial agents on selection for resistance and the most appropriate treatment regimens to limit the development of resistance is incomplete. Surveillance programmes monitoring the occurrence and development of resistance and consumption...... or humans. The emergence of resistant bacteria and resistance genes following the use of antimicrobial agents is relatively well documented and it seems evident that all antimicrobial agents will select for resistance. However, current knowledge regarding the occurrence of antimicrobial resistance in food...

  7. The impact of different antibiotic regimens on the emergence of antimicrobial-resistant bacteria.

    Directory of Open Access Journals (Sweden)

    Erika M C D'Agata

    Full Text Available BACKGROUND: The emergence and ongoing spread of antimicrobial-resistant bacteria is a major public health threat. Infections caused by antimicrobial-resistant bacteria are associated with substantially higher rates of morbidity and mortality compared to infections caused by antimicrobial-susceptible bacteria. The emergence and spread of these bacteria is complex and requires incorporating numerous interrelated factors which clinical studies cannot adequately address. METHODS/PRINCIPAL FINDINGS: A model is created which incorporates several key factors contributing to the emergence and spread of resistant bacteria including the effects of the immune system, acquisition of resistance genes and antimicrobial exposure. The model identifies key strategies which would limit the emergence of antimicrobial-resistant bacterial strains. Specifically, the simulations show that early initiation of antimicrobial therapy and combination therapy with two antibiotics prevents the emergence of resistant bacteria, whereas shorter courses of therapy and sequential administration of antibiotics promote the emergence of resistant strains. CONCLUSIONS/SIGNIFICANCE: The principal findings suggest that (i shorter lengths of antibiotic therapy and early interruption of antibiotic therapy provide an advantage for the resistant strains, (ii combination therapy with two antibiotics prevents the emergence of resistance strains in contrast to sequential antibiotic therapy, and (iii early initiation of antibiotics is among the most important factors preventing the emergence of resistant strains. These findings provide new insights into strategies aimed at optimizing the administration of antimicrobials for the treatment of infections and the prevention of the emergence of antimicrobial resistance.

  8. Antimicrobial constituents of Foeniculum vulgare.

    Science.gov (United States)

    Kwon, Yong Soo; Choi, Won Gyu; Kim, Won Jun; Kim, Woo Kyung; Kim, Myong Jo; Kang, Won Hee; Kim, Chang Min

    2002-04-01

    A phenyl propanoid derivative, dillapional(1) was found to be a antimicrobial principle of the stems of Foeniculum vulgare (Umbelliferae) with MIC values of 125, 250 and 125/ against Bacillus subtilis, Aspergillus niger and Cladosporium cladosporioides, respectively. A coumarin derivative, scopoletin(2) was also isolated as marginally antimicrobial agent along with inactive compounds, dillapiol(3), bergapten(4), imperatorin(5) and psolaren(6) from this plant. The isolates 1-6 were not active against the Escherichia coli.

  9. Antimicrobials for bacterial bioterrorism agents.

    Science.gov (United States)

    Sarkar-Tyson, Mitali; Atkins, Helen S

    2011-06-01

    The limitations of current antimicrobials for highly virulent pathogens considered as potential bioterrorism agents drives the requirement for new antimicrobials that are suitable for use in populations in the event of a deliberate release. Strategies targeting bacterial virulence offer the potential for new countermeasures to combat bacterial bioterrorism agents, including those active against a broad spectrum of pathogens. Although early in the development of antivirulence approaches, inhibitors of bacterial type III secretion systems and cell division mechanisms show promise for the future.

  10. The safety of antimicrobial drugs

    OpenAIRE

    Ćupić Vitomir; Jezdimirović Milanka; Dobrić Silva; Ivanović Saša; Ćupić-Miladinović Dejana

    2016-01-01

    The discovery and introduction of antimicrobial drugs in clinical practice has been recorded as one of the greatest achievements in the history of medicine. The application of these drugs, made a big, almost revolutionary upheaval in treatment of many infectious diseases. Its significance for the humanity lies in the fact that hundreds of thousands of people, until then condemned to a certain death, has been saved now. However, it was shown that antimicrobi...

  11. [Role of antimicrobial peptides (AMP) and pattern recognition receptors (PRR) in the intestinal mucosa homeostasis].

    Science.gov (United States)

    Lapis, Károly

    2009-11-22

    Homeostasis and integrity of bowel mucosa is assured by well controlled mechanical, biochemical and immunological mechanisms. First line of defense is presented by the antimicrobial peptides (AMP), which form a continuous layer on the bowel surface, produced by intestinal specific (Paneth) and non-specific epithelial cells. AMPs have a significant antimicrobial, antifungal and antiviral, as well as immunomodulatory effects. Next line of defense is the pattern recognition receptors (PRR), which allows identifying conservative molecular patterns of different pathogens, and starts antimicrobial and inflammatory mechanisms through gene-expression induction. We review the most recent knowledge and studies concerning these mechanisms.

  12. Detection of essential genes in Streptococcus pneumoniae using bioinformatics and allelic replacement mutagenesis.

    Science.gov (United States)

    Song, Jae-Hoon; Ko, Kwan Soo

    2008-01-01

    Although the emergence and spread of antimicrobial resistance in major bacterial pathogens for the past decades poses a growing challenge to public health, discovery of novel antimicrobial agents from natural products or modification of existing antibiotics cannot circumvent the problem of antimicrobial resistance. The recent development of bacterial genomics and the availability of genome sequences allow the identification of potentially novel antimicrobial agents. The cellular targets of new antimicrobial agents must be essential for the growth, replication, or survival of the bacterium. Conserved genes among different bacterial genomes often turn out to be essential (1, 2). Thus, the combination of comparative genomics and the gene knock-out procedure can provide effective ways to identify the essential genes of bacterial pathogens (3). Identification of essential genes in bacteria may be utilized for the development of new antimicrobial agents because common essential genes in diverse pathogens could constitute novel targets for broad-spectrum antimicrobial agents.

  13. Responses of Pseudomonas aeruginosa to antimicrobials

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    Yuji eMorita

    2014-01-01

    Full Text Available Infections caused by Pseudomonas aeruginosa often are hard to treat; inappropriate chemotherapy readily selects multidrug-resistant P. aeruginosa. This organism can be exposed to a wide range of concentrations of antimicrobials during treatment; learning more about the responses of P. aeruginosa to antimicrobials is therefore important. We review here responses of the bacterium P. aeruginosa upon exposure to antimicrobials at levels below the inhibitory concentration.Carbapenems (e.g., imipenem have been shown to induce the formation of thicker and more robust biofilms, while fluoroquinolones (e.g., ciprofloxacin and aminoglycosides (e.g., tobramycin have been shown to induce biofilm formation. Ciprofloxacin also has been demonstrated to enhance the frequency of mutation to carbapenem resistance. Conversely, although macrolides (e.g., azithromycin typically are not effective against P. aeruginosa because of the pseudomonal outer-membrane impermeability and efflux, macrolides do lead to a reduction in virulence factor production. Similarly, tetracycline is not very effective against this organism, but is known to induce the type-III secretion system and consequently enhance cytotoxicity of P. aeruginosa in vivo. Of special note are the effects of antibacterials and disinfectants on pseudomonal efflux systems. Sub-inhibitory concentrations of protein synthesis inhibitors (aminoglycosides, tetracycline, chloramphenicol, etc. induce the MexXY multidrug efflux system. This response is known to be mediated by interference with the translation of the leader peptide PA5471.1, with consequent effects on expression of the PA5471 gene product. Additionally, induction of the MexCD-OprJ multidrug efflux system is observed upon exposure to sub-inhibitory concentrations of disinfectants such as chlorhexidine and benzalkonium. This response is known to be dependent upon the AlgU stress response factor.Altogether, these biological responses of P. aeruginosa

  14. Antimicrobial peptide LL-37 participates in the transcriptional regulation of melanoma cells

    Science.gov (United States)

    Muñoz, Mindy; Craske, Madeleine; Severino, Patricia; de Lima, Thais Martins; Labhart, Paul; Chammas, Roger; Velasco, Irineu Tadeu; Machado, Marcel Cerqueira César; Egan, Brian; Nakaya, Helder I; Pinheiro da Silva, Fabiano

    2016-01-01

    Antimicrobial peptides are an ancient family of molecules that emerged millions of years ago and have been strongly conserved during the evolutionary process of living organisms. Recently, our group described that the human antimicrobial peptide LL-37 migrates to the nucleus, raising the possibility that LL-37 could directly modulate transcription under certain conditions. Here, we showed evidence that LL-37 binds to gene promoter regions, and LL-37 gene silencing changed the transcriptional program of melanoma A375 cells genes associated with histone, metabolism, cellular stress, ubiquitination and mitochondria. PMID:27994673

  15. Toxin genes detection and antimicrobial susceptibility test of Staphylococcus aureus isolated from retail chicken in Shaanxi Province%陕西省市售鸡肉中金黄色葡萄球菌的毒力基因及其药敏检测

    Institute of Scientific and Technical Information of China (English)

    徐本锦; 张伟松; 王新; 杨保伟; 席美丽; 夏效东; 孟江洪; 李新平

    2012-01-01

    To investigate the prevalence of toxin genes and antimicrobial profiles of Staphylococcus aureus (S. aureus) strains isolated from retail chicken in Shaanxi Province , a total of 122 S . aureus isolates from retail chicken were tested for the prevalence of nine enterotoxin genes and four exotoxin genes by polymerase chain reaction , and tested for antimicrobial susceptibility with 14 antibiotics by the agar dilution method . In the 122 strains of S. aureus, 59 .84% were positive for one or more toxin genes . The 25 .41% of the isolates harbored pvl gene, 51 .64% harbored one or more ses genes, sej (37 .70% ) was the most common pattern , and 4 .92% were positive for mecA gene. None of the isolates harbored see, seg, sei, ets or tsst-1 genes . A total of 20 toxin gene profiles were obtained , and sej (21 .31% ) was the most common profile , following by pvl (8 .20% ) , sej+pvl (4 .92% ), seh+sej+pvl (3 .28% ) and seh+pvl (3 .28% ) . Of these S. aureus isolates , 100 .0% were resistant to at least one antimicrobial , and 88.52% to three or more antimicrobials . Resistance was most frequently observed on erythromycin (87. 70% ), following by trimethoprim/siilfamethoxazole (81.97%), tetracycline (67.21% ), amikacin (59.02%), ciprofloxacin(53 .28% ), oxacillin (52.46% ) and amoxicil-lin/clavulanic acid (40 .16% ) . While significantly fewer isolates were resistant to ampicillin (32 .79% ), chlorampheni-col (27 .05% ) , gentamicin (20 .49% ), cefoxitin (13 .11% ) and cefoperazone (2 .46%). None of the; isolates was resistant to vancomycin . These findings indicated that many S. aureus i-solates from retail chicken in Shaanxi Province harbored multiple toxin genes and exhibited multiple antimicrobial resistances . The presence of S. aureus strains and methicillin-resistant S. aureus (MRSA) in retail chicken poses a potential threat to consumer health , so relevant regulation should be established to strengthen hygiene management of the chicken products .%目的

  16. Editorial of the Special Issue Antimicrobial Polymers

    Directory of Open Access Journals (Sweden)

    Iolanda Francolini

    2013-09-01

    Full Text Available The special issue “Antimicrobial Polymers” includes research and review papers concerning the recent advances on preparation of antimicrobial polymers and their relevance to industrial settings and biomedical field. Antimicrobial polymers have recently emerged as promising candidates to fight microbial contamination onto surfaces thanks to their interesting properties. In this special issue, the main strategies pursued for developing antimicrobial polymers, including polymer impregnation with antimicrobial agents or synthesis of polymers bearing antimicrobial moieties, were discussed. The future application of these polymers either in industrial or healthcare settings could result in an extremely positive impact not only at the economic level but also for the improvement of quality of life.

  17. Meta-genomic analysis of toilet waste from long distance flights; a step towards global surveillance of infectious diseases and antimicrobial resistance

    DEFF Research Database (Denmark)

    Petersen, Thomas Nordahl; Rasmussen, Simon; Hasman, Henrik

    2015-01-01

    for bacteria and antimicrobial resistance genes. An average of 106,839 (0.06%) reads were assigned to resistance genes with genes encoding resistance to tetracycline, macrolide and beta-lactam resistance genes as the most abundant in all samples. We found significantly higher abundance and diversity of genes...

  18. Antimicrobial resistance in bacteria from horses: Epidemiology of antimicrobial resistance.

    Science.gov (United States)

    Maddox, T W; Clegg, P D; Williams, N J; Pinchbeck, G L

    2015-11-01

    Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections. While the epidemiology of antimicrobial resistance in bacteria from man has been studied extensively, less work has been undertaken in companion animals, particularly horses. Methicillin-resistant Staphylococcus aureus has been identified as a cause of infections, with a low prevalence of nasal carriage by horses in the community but higher for hospitalised horses. Molecular characterisation has shown methicillin-resistant Staphylococcus aureus strains either to be predominantly of types associated with horses or of sequence type ST398. Antimicrobial-resistant Escherichia coli (including multidrug-resistant and extended spectrum β-lactamase-producing isolates) have caused infections and been documented in faecal carriage by horses, with many significant resistance mechanisms identified. More sporadic reports and molecular characterisation exist for resistance in other bacteria such as enterococci, Salmonella, Acinetobacter and Pseudomonas species. Limited work has been undertaken evaluating risk factors and much of the epidemiology of antimicrobial resistance in bacteria from horses remains to be determined.

  19. De Novo Transcriptome Analysis and Detection of Antimicrobial Peptides of the American Cockroach Periplaneta americana (Linnaeus.

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    In-Woo Kim

    Full Text Available Cockroaches are surrogate hosts for microbes that cause many human diseases. In spite of their generally destructive nature, cockroaches have recently been found to harbor potentially beneficial and medically useful substances such as drugs and allergens. However, genomic information for the American cockroach (Periplaneta americana is currently unavailable; therefore, transcriptome and gene expression profiling is needed as an important resource to better understand the fundamental biological mechanisms of this species, which would be particularly useful for the selection of novel antimicrobial peptides. Thus, we performed de novo transcriptome analysis of P. americana that were or were not immunized with Escherichia coli. Using an Illumina HiSeq sequencer, we generated a total of 9.5 Gb of sequences, which were assembled into 85,984 contigs and functionally annotated using Basic Local Alignment Search Tool (BLAST, Gene Ontology (GO, and Kyoto Encyclopedia of Genes and Genomes (KEGG database terms. Finally, using an in silico antimicrobial peptide prediction method, 86 antimicrobial peptide candidates were predicted from the transcriptome, and 21 of these peptides were experimentally validated for their antimicrobial activity against yeast and gram positive and -negative bacteria by a radial diffusion assay. Notably, 11 peptides showed strong antimicrobial activities against these organisms and displayed little or no cytotoxic effects in the hemolysis and cell viability assay. This work provides prerequisite baseline data for the identification and development of novel antimicrobial peptides, which is expected to provide a better understanding of the phenomenon of innate immunity in similar species.

  20. Antimicrobial activity of flavonoids.

    Science.gov (United States)

    Cushnie, T P Tim; Lamb, Andrew J

    2005-11-01

    Flavonoids are ubiquitous in photosynthesising cells and are commonly found in fruit, vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. For centuries, preparations containing these compounds as the principal physiologically active constituents have been used to treat human diseases. Increasingly, this class of natural products is becoming the subject of anti-infective research, and many groups have isolated and identified the structures of flavonoids possessing antifungal, antiviral and antibacterial activity. Moreover, several groups have demonstrated synergy between active flavonoids as well as between flavonoids and existing chemotherapeutics. Reports of activity in the field of antibacterial flavonoid research are widely conflicting, probably owing to inter- and intra-assay variation in susceptibility testing. However, several high-quality investigations have examined the relationship between flavonoid structure and antibacterial activity and these are in close agreement. In addition, numerous research groups have sought to elucidate the antibacterial mechanisms of action of selected flavonoids. The activity of quercetin, for example, has been at least partially attributed to inhibition of DNA gyrase. It has also been proposed that sophoraflavone G and (-)-epigallocatechin gallate inhibit cytoplasmic membrane function, and that licochalcones A and C inhibit energy metabolism. Other flavonoids whose mechanisms of action have been investigated include robinetin, myricetin, apigenin, rutin, galangin, 2,4,2'-trihydroxy-5'-methylchalcone and lonchocarpol A. These compounds represent novel leads, and future studies may allow the development of a pharmacologically acceptable antimicrobial agent or class of agents.

  1. Prevalence of antimicrobial resistance and integrons in Escherichia Coli from Punjab, Pakistan

    Directory of Open Access Journals (Sweden)

    Idrees Muhammad

    2011-06-01

    Full Text Available Antimicrobial resistance was studied in Escherichia coli strains isolated from urine samples of 457 patients suffering from urinary tract infection. High prevalence of class 1 integrons (43.56%, sulfamethoxazole resistance genes sul1 (45.54% and sul2 (51.48% along with occurrence of quinolone resistance genes was detected in multi drug resistance isolates.

  2. Novel histone-derived antimicrobial peptides use different antimicrobial mechanisms.

    Science.gov (United States)

    Pavia, Kathryn E; Spinella, Sara A; Elmore, Donald E

    2012-03-01

    The increase in multidrug resistant bacteria has sparked an interest in the development of novel antibiotics. Antimicrobial peptides that operate by crossing the cell membrane may also have the potential to deliver drugs to intracellular targets. Buforin 2 (BF2) is an antimicrobial peptide that shares sequence identity with a fragment of histone subunit H2A and whose bactericidal mechanism depends on membrane translocation and DNA binding. Previously, novel histone-derived antimicrobial peptides (HDAPs) were designed based on properties of BF2, and DesHDAP1 and DesHDAP3 showed significant antibacterial activity. In this study, their DNA binding, permeabilization, and translocation abilities were assessed independently and compared to antibacterial activity to determine whether they share a mechanism with BF2. To investigate the importance of proline in determining the peptides' mechanisms of action, proline to alanine mutants of the novel peptides were generated. DesHDAP1, which shows significant similarities to BF2 in terms of secondary structure, translocates effectively across lipid vesicle and bacterial membranes, while the DesHDAP1 proline mutant shows reduced translocation abilities and antimicrobial potency. In contrast, both DesHDAP3 and its proline mutant translocate poorly, though the DesHDAP3 proline mutant is more potent. Our findings suggest that a proline hinge can promote membrane translocation in some peptides, but that the extent of its effect on permeabilization depends on the peptide's amphipathic properties. Our results also highlight the different antimicrobial mechanisms exhibited by histone-derived peptides and suggest that histones may serve as a source of novel antimicrobial peptides with varied properties.

  3. Analysis of Drug Resistance and Resistant Genes of Salmonella toβ-lactams Antimicrobial Agents Isolated from Pigs in Guizhou Province%贵州省猪源沙门氏菌对β-内酰胺类药耐药性及耐药基因分析

    Institute of Scientific and Technical Information of China (English)

    曹正花; 谭艾娟; 吕世明; 王雄; 杜国琴

    2016-01-01

    In order to analyse the resistance toβ-lactams antimicrobial agents and the prevalence of resistant genes of Salmonella in Guizhou province,130 Salmonella strains were isolated and iden-tified from 9 different regions of scale pig farms.The drug sensitivity to 8 kinds ofβ-lactams anti-microbial agents were determined by using the broth microdilution method.Allβ-lactams resistant isolates were detected for the presences of TEM,OXA,CTX-M and SHV genes by PCR.The re-sults showed that drug resistance of Salmonella to the commonly usedβ-lactams antimicrobial agents was very serious,and the resistance rate to ceftazidime was the highest (100%),followed by ampicillin and amoxicillin,were 76.15% and 80.77%,respectively.The resistance rates of ceft-iofur and cephalexin were the lowest (46.15%).Salmonella strains were all of multiple drug re-sistance,of which double resistance was at lowest (2.31%),and eightfold resistance was highest (4.62%),multidrug resistance mainly concentrated in fourfold to sevenfold,accounted for 88.46%.PCR results showed that TEM,OXA,CTX-M genes detection rate were 85%,75% and 46%,respectively,while the SHV gene was not inspected.Resistant phenotype was basically con-sistent with resistant genes.The results indicated that the resistance of Salmonella stains from pig toβ-lactams antimicrobial agents were widespread,and ceftazidime was particularly serious. The TEM,OXA and CTX-M genes were mainly carriedβ-lactams resistant genes in Salmonella isolates from Guizhou province.It had a great relationship between the prevalence of resistance genes and growth of antimicrobial resistance.%为了解贵州省猪源沙门氏菌对β-内酰胺类抗菌药物耐药性及其耐药基因的流行情况,本试验从贵州省9个地区规模养猪场中分离鉴定130株沙门氏菌,采用微量肉汤稀释法测定其对常用的8种β-内酰胺类抗菌药物的敏感性,并用PCR法对β-内酰胺酶耐药基因进行检测。结果显示,沙门氏菌对常

  4. Antimicrobial activities of squalamine mimics.

    Science.gov (United States)

    Kikuchi, K; Bernard, E M; Sadownik, A; Regen, S L; Armstrong, D

    1997-07-01

    We investigated the antimicrobial properties of compounds with structural features that were designed to mimic those of squalamine, an antibiotic isolated from the stomach of the dogfish shark. The mimics, like squalamine, are sterol-polyamine conjugates. Unlike squalamine, the mimics were simple to prepare, at high yield, from readily available starting materials. Several squalamine mimics showed activity against gram-negative rods, gram-positive cocci including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and fungi. Some had little or no hemolytic activity. The hydrophobicity of the sterol backbone and the length and the cationic charge of the side chains appeared to be critical determinants of activity. One of the squalamine mimics, SM-7, was bactericidal against Escherichia coli, Pseudomonas aeruginosa, and S. aureus; its activity was decreased by divalent or monovalent cations and by bovine serum albumin. Subinhibitory concentrations of SM-7 markedly enhanced the antimicrobial activity of rifampin against gram-negative rods. These results suggest that the compounds may disrupt an outer membrane of gram-negative rods. Squalamine mimics are a new class of broad-spectrum antimicrobial agents. The antagonism of their activity by serum and albumin and their hemolytic properties may limit their use as systemic agents. The squalamine mimics, because of their potencies, broad spectra of antimicrobial activity, and potential for systemic toxicity, appear to be good candidates for development as topical antimicrobial agents.

  5. Antimicrobial stewardship in small animal veterinary practice

    DEFF Research Database (Denmark)

    Guardabassi, Luca; Prescott, John F

    2015-01-01

    Despite the increasing recognition of the critical role for antimicrobial stewardship in preventing the spread of multidrug-resistant bacteria, examples of effective antimicrobial stewardship programs are rare in small animal veterinary practice. This article highlights the basic requirements...

  6. Antimicrobial resistances do not affect colonization parameters of intestinal E. coli in a small piglet group

    Directory of Open Access Journals (Sweden)

    Schierack Peter

    2009-10-01

    Full Text Available Abstract Background Although antimicrobial resistance and persistence of resistant bacteria in humans and animals are major health concerns worldwide, the impact of antimicrobial resistance on bacterial intestinal colonization in healthy domestic animals has only been rarely studied. We carried out a retrospective analysis of the antimicrobial susceptibility status and the presence of resistance genes in intestinal commensal E. coli clones from clinically healthy pigs from one production unit with particular focus on effects of pheno- and/or genotypic resistance on different nominal and numerical intestinal colonization parameters. In addition, we compared the occurrence of antimicrobial resistance phenotypes and genotypes with the occurrence of virulence associated genes typical for extraintestinal pathogenic E. coli. Results In general, up to 72.1% of all E. coli clones were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, sulfamethoxazole or tetracycline with a variety of different resistance genes involved. There was no significant correlation between one of the nominal or numerical colonization parameters and the absence or presence of antimicrobial resistance properties or resistance genes. However, there were several statistically significant associations between the occurrence of single resistance genes and single virulence associated genes. Conclusion The demonstrated resistance to the tested antibiotics might not play a dominant role for an intestinal colonization success in pigs in the absence of antimicrobial drugs, or cross-selection of other colonization factors e.g. virulence associated genes might compensate "the cost of antibiotic resistance". Nevertheless, resistant strains are not outcompeted by susceptible bacteria in the porcine intestine. Trial Registration The study was approved by the local animal welfare committee of the "Landesamt für Arbeitsschutz, Gesundheitsschutz und technische Sicherheit" Berlin

  7. Antimicrobial-resistant Shigella infections from Iran

    DEFF Research Database (Denmark)

    Tajbakhsh, Mercedeh; García Migura, Lourdes; Rahbar, Mohammad

    2012-01-01

    . ; Results: Of the isolates, 25 (68%) were S. sonnei phase II, with 5 (14%) S. flexneri, 5 (14%) Shigella dysenteriae type 2, and 2 (5%) Shigella boydii type 2. Resistance to at least threeclasses of antimicrobials was detected in all species. The presence of blaCTX-M-15 and the AmpC β-lactamase producer bla...... or the presence of an endemic clone in Iran. ; Conclusions: This is the first known description of ESBL-producing and AmpC β-lactamase-producing Shigella and of PMQR Shigella in Iran. The emergence of CTX-15, CMY-2 and qnrS1 genes may compromise the treatment of shigellosis. Strategies to minimize the spread...

  8. Antimicrobial resistance in India: A review

    OpenAIRE

    2013-01-01

    Antimicrobial resistance is an important concern for the public health authorities at global level. However, in developing countries like India, recent hospital and some community based data showed increase in burden of antimicrobial resistance. Research related to antimicrobial use, determinants and development of antimicrobial resistance, regional variation and interventional strategies according to the existing health care situation in each country is a big challenge. This paper discusses ...

  9. Antimicrobial Properties of Titanium Nanoparticles

    Science.gov (United States)

    Erdural, B. K.; Yurum, A.; Bakir, U.; Karakas, G.

    In the present study, nanostructured titania particles were synthesized using hydrothermal processing and their photocatalytic antimicrobial activities were characterized. Sol-gel synthesized TiO2 samples were treated with a two step hydrothermal treatment. The first stage treatment was the alkaline treatment with 10 M of NaOH for 48 h at 130°C, followed with the second step which applied with distilled water for 48 h at 200°C. Scanning Electron Microscope (SEM) images showed that alkaline treatment yields lamellar structure particles from the sol-gel synthesized anatase. Further treatment of nanoplates with distilled water results in crystal growth and the formation of nano structured thorn like particles. The photocatalytic antimicrobial activities of samples were determined against Escherichia coli under solar irradiation for 4 h. It was observed that the samples treated under alkaline conditions have higher antimicrobial activity than the untreated samples.

  10. [Isolation and antimicrobial activities of actinomycetes from vermicompost].

    Science.gov (United States)

    Wang, Xue-jun; Yan, Shuang-lin; Min, Chang-li; Yang, Yan

    2015-02-01

    In this paper, actinomycetes were isolated from vermicompost by tablet coating method. Antimicrobial activities of actinomycetes were measured by the agar block method. Strains with high activity were identified based on morphology and biochemical characteristics, as well as 16S rDNA gene sequence analysis. The results showed that 26 strains of actinomycetes were isolated, 16 of them had antimicrobial activities to the test strains which accounts for 61.54% of all strains. Among the 16 strains, the strain QYF12 and QYF22 had higher antimicrobial activity to Micrococcus luteus, with a formed inhibition zone of 27 mm and 31 mm, respectively. While the strain QYF26 had higher antimicrobial activity to Bacillus subtilis, and the inhibition zone diameter was 21 mm. Based on the identification of strains with high activity, the strain QYF12 was identified as Streptomyces chartreusis, the strain QYF22 was S. ossamyceticus and the strain QYF26 was S. gancidicus. This study provided a theoretical basis for further separate antibacterial product used for biological control.

  11. Sixty years of antimicrobial use in animals

    DEFF Research Database (Denmark)

    Guardabassi, Luca

    2013-01-01

    This, the last in our series of feature articles celebrating 125 years of Veterinary Record, aims to provide an overview of antimicrobial use in animals. Starting with a journey through the history of antimicrobial use in animals, Luca Guardabassi gives his opinion on the current zoonotic risks...... associated with antimicrobial resistance and on how these risks might be tackled in the years to come....

  12. Molecular characterization of multidrug resistant hospital isolates using the antimicrobial resistance determinant microarray.

    Directory of Open Access Journals (Sweden)

    Tomasz A Leski

    Full Text Available Molecular methods that enable the detection of antimicrobial resistance determinants are critical surveillance tools that are necessary to aid in curbing the spread of antibiotic resistance. In this study, we describe the use of the Antimicrobial Resistance Determinant Microarray (ARDM that targets 239 unique genes that confer resistance to 12 classes of antimicrobial compounds, quaternary amines and streptothricin for the determination of multidrug resistance (MDR gene profiles. Fourteen reference MDR strains, which either were genome, sequenced or possessed well characterized drug resistance profiles were used to optimize detection algorithms and threshold criteria to ensure the microarray's effectiveness for unbiased characterization of antimicrobial resistance determinants in MDR strains. The subsequent testing of Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae hospital isolates revealed the presence of several antibiotic resistance genes [e.g. belonging to TEM, SHV, OXA and CTX-M classes (and OXA and CTX-M subfamilies of β-lactamases] and their assemblages which were confirmed by PCR and DNA sequence analysis. When combined with results from the reference strains, ~25% of the ARDM content was confirmed as effective for representing allelic content from both Gram-positive and -negative species. Taken together, the ARDM identified MDR assemblages containing six to 18 unique resistance genes in each strain tested, demonstrating its utility as a powerful tool for molecular epidemiological investigations of antimicrobial resistance in clinically relevant bacterial pathogens.

  13. Immunohistochemical distribution of cocaine and amphetamine regulatory peptide-like immunoreactive (CART-LI) nerve fibers in the circular muscle layer and their relationship to other peptides in the human caecum.

    Science.gov (United States)

    Bulc, Michał; Gonkowski, Sławomir; Landowski, Piotr; Kamińska, Barbara; Całka, Jarosław

    2014-07-01

    Motor activity of the gastrointestinal tract is extensively controlled by the enteric nervous system (ENS). Numerous neurotransmitters and neuromodulators are responsible for this regulation. One of them is cocaine- and amphetamine-regulated transcript peptide (CART). So far, there are few reports available concerning the distribution, functions, and co-localization of CART in the human gastrointestinal tract. The aim of the present investigation was to study the distribution and degree of co-localization of CART with substances taking part in conducting sensory stimuli, such as: substance P (SP), neurokinin A (NKA), calcitonin gene related peptide (CGRP) and Leu 5 enkephalin (L-ENK) in the circular muscle layer of the human caecum. CART-like immunoreactive (CART-LI) nerve fibers formed a very dense meshwork in the circular muscle layer of the caecum in all patients studied. Moreover, all neuronal substances tested during the present investigation were observed in CART-LI processes, but the degree of co-localization depended on the type of substance. The highest number of CART-positive nerves also contained L-ENK. A slightly lower level of co-localization was observed in the case of CART and SP or NKA, while only single nerve fibers were simultaneously CART- and CGRP-positive.

  14. Distribution of antimicrobial-resistant lactic acid bacteria in natural cheese in Japan.

    Science.gov (United States)

    Ishihara, Kanako; Nakajima, Kumiko; Kishimoto, Satoko; Atarashi, Fumiaki; Muramatsu, Yasukazu; Hotta, Akitoyo; Ishii, Satomi; Takeda, Yasuyuki; Kikuchi, Masanori; Tamura, Yutaka

    2013-10-01

    To determine and compare the extent of contamination caused by antimicrobial-resistant lactic acid bacteria (LAB) in imported and domestic natural cheeses on the Japanese market, LAB were isolated using deMan, Rogosa and Sharpe (MRS) agar and MRS agar supplemented with six antimicrobials. From 38 imported and 24 Japanese cheeses, 409 LAB isolates were obtained and their antimicrobial resistance was tested. The percentage of LAB resistant to dihydrostreptomycin, erythromycin, and/or oxytetracycline isolated from imported cheeses (42.1%) was significantly higher than that of LAB resistant to dihydrostreptomycin or oxytetracycline from cheeses produced in Japan (16.7%; P=0.04). Antimicrobial resistance genes were detected in Enterococcus faecalis (tetL, tetM, and ermB; tetL and ermB; tetM) E. faecium (tetM), Lactococcus lactis (tetS), Lactobacillus (Lb.), casei/paracasei (tetM or tetW), and Lb. rhamnosus (ermB) isolated from seven imported cheeses. Moreover, these E. faecalis isolates were able to transfer antimicrobial resistance gene(s). Although antimicrobial resistance genes were not detected in any LAB isolates from Japanese cheeses, Lb. casei/paracasei and Lb. coryniformis isolates from a Japanese farm-made cheese were resistant to oxytetracycline (minimal inhibitory concentration [MIC], 32 µg/mL). Leuconostoc isolates from three Japanese farm-made cheeses were also resistant to dihydrostreptomycin (MIC, 32 to >512 µg/mL). In conclusion, the present study demonstrated contamination with antimicrobial-resistant LAB in imported and Japanese farm-made cheeses on the Japanese market, but not in Japanese commercial cheeses.

  15. Antimicrobial Activity of Subtilin from Bacillus Subtilis JDB-1 and Cloning spaS Gene%泡桐内生枯草芽孢杆菌JDB-1草菌素的抑菌活性及其spaS基因的克隆

    Institute of Scientific and Technical Information of China (English)

    吴瑞方; 龚凤娟; 杨镒蔓; 恩特马克·布拉提白

    2011-01-01

    用硫酸铵沉淀法从泡桐内生枯草芽孢杆菌JDB-1发酵液中粗提枯草菌素,采用纸片扩散法和琼脂糖扩散法分别检测枯草菌素对细菌和真菌的抑菌活性,采用PCR从菌株JDB-1基因组DNA中扩增出枯草菌素基因spaS,并克隆到pMD18-T载体,测定spaS基因的核苷酸序列.结果表明硫酸铵粗提的枯草菌素对大肠杆菌K12、恶臭假单胞杆菌AS1.1003、赤霉菌JSD-2、赤霉菌JSD-7和白色念珠菌ATCC10123等细菌和和真菌具有较强的抑制活性.DNA测序结果显示spaS基因大小为171bp,与已报道不同菌株spaS基因核苷酸序列的同源性为95%.%The bacterial subtilin was purified from the fermentation broth of Bacillus subtilis JDB-1 by using the ammonium sulfate precipitation,and its antimicrobial activity against five tested microorganisms was investigated by using the agar diffusion test or the paper disc test.The spaS gene encoding subtilin was amplified from genomic DNA of Bacillus subtilis JDB-1 by PCR,and the PCR products cloned into the pMD18-T vector and subsequently introduced the competent cells of E.coli DH5α.The recombinant plasmid pMD18-spaS was identified by PCR and then sequenced.The results showed that the purified subtilin displayed antimicrobial activities against E.coli K12,Pseudomonas putida AS1.1003,Gibberella moniliformis JSD-8 and Candida albicans ATCC10123,respectively.The sequence analysis showed that the coding region spaS gene of Bacillus subtilis JDB-1 was 171bp in length,and the nucleotide sequence similarity of the spaS genes between the JDB-1 strain and the previously reported other bacterial strains was 95%.

  16. Durable and Rechargeable Antimicrobial Textiles

    Science.gov (United States)

    2013-12-01

    investigator (PI), Dr. Zhengbing Cao, has 8 years of experience in the development of antimicrobial materials, such as silver, zinc , quaternary...for persons with diabetes , as well as other R&D activities. The PI is in close contact with other researchers exploring the N-halamine technique for

  17. Antimicrobial activity of Securidaca longipedunculata.

    Science.gov (United States)

    Ajali, U; Chukwurah, B K C

    2004-11-01

    The folk herbal uses of Securidaca longipedunculata in the treatment of diarrhea, boils, gonorrhea, and cough prompted phytochemical analyses and antimicrobial activity screening of extracts of the root. Some flavonoids isolated showed activity against many micro-organisms. These flavonoids were isolated using chromatographic methods.

  18. Helical Antimicrobial Sulfono- {gamma} -AApeptides

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yaqiong; Wu, Haifan; Teng, Peng; Bai, Ge; Lin, Xiaoyang; Zuo, Xiaobing; Cao, Chuanhai; Cai, Jianfeng

    2015-06-11

    Host-defense peptides (HDPs) such as magainin 2 have emerged as potential therapeutic agents combating antibiotic resistance. Inspired by their structures and mechanism of action, herein we report the fi rst example of antimicrobial helical sulfono- γ - AApeptide foldamers. The lead molecule displays broad-spectrum and potent antimicrobial activity against multi-drug-resistant Gram- positive and Gram-negative bacterial pathogens. Time-kill studies and fl uorescence microscopy suggest that sulfono- γ -AApeptides eradicate bacteria by taking a mode of action analogous to that of HDPs. Clear structure - function relationships exist in the studied sequences. Longer sequences, presumably adopting more-de fi ned helical structures, are more potent than shorter ones. Interestingly, the sequence with less helical propensity in solution could be more selective than the stronger helix-forming sequences. Moreover, this class of antimicrobial agents are resistant to proteolytic degradation. These results may lead to the development of a new class of antimicrobial foldamers combating emerging antibiotic-resistant pathogens.

  19. Antimicrobial Polymers with Metal Nanoparticles

    Directory of Open Access Journals (Sweden)

    Humberto Palza

    2015-01-01

    Full Text Available Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms.

  20. Antimicrobial Activity of Resveratrol Analogues

    Directory of Open Access Journals (Sweden)

    Malik Chalal

    2014-06-01

    Full Text Available Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew. Stilbenes displayed a spectrum of activity ranging from low to high. Six of them, including the most active ones, were subsequently tested on the development of Botrytis cinerea (fungus responsible for grey mold. The results obtained allowed us to identify the most active stilbenes against both grapevine pathogens, to compare the antimicrobial activity of the evaluated series of stilbenes, and to discuss the relationship between their chemical structure (number and position of methoxy and hydroxy groups and antimicrobial activity.

  1. Combating Antimicrobial Resistance in Foodborne Microorganisms.

    Science.gov (United States)

    Lai, Edward P C; Iqbal, Zafar; Avis, Tyler J

    2016-02-01

    This review addresses an important public health hazard affecting food safety. Antimicrobial agents are used in foods to reduce or eliminate microorganisms that cause disease. Many traditional organic compounds, novel synthetic organic agents, natural products, peptides, and proteins have been extensively studied for their effectiveness as antimicrobial agents against foodborne Campylobacter spp., Escherichia coli, Listeria spp. and Salmonella. However, antimicrobial resistance can develop in microorganisms, enhancing their ability to withstand the inhibiting or killing action of antimicrobial agents. Knowledge gaps still exist with regard to the actual chemical and microbiological mechanisms that must be identified to facilitate the search for new antimicrobial agents. Technical implementation of antimicrobial active packing films and coatings against target microorganisms must also be improved for extended product shelf life. Recent advances in antimicrobial susceptibility testing can provide researchers with new momentum to pursue their quest for a resistance panacea.

  2. Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

    Directory of Open Access Journals (Sweden)

    André Horta

    2014-03-01

    Full Text Available Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1 extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC, 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging activity and oxygen radical absorbance capacity (ORAC. Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%, Alteromonas sp. (12.82%, Shewanella sp. (12.26%, Serratia sp. (2.56%, Citricoccus sp. (2.56%, Cellulophaga sp. (2.56%, Ruegeria sp. (2.56% and Staphylococcus sp. (2.56%. Six (15.38% of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis was exhibited by strain 16 (Shewanella sp.. Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.

  3. Antimicrobial Activity of UV-Induced Phenylamides from Rice Leaves

    Directory of Open Access Journals (Sweden)

    Hye Lin Park

    2014-11-01

    Full Text Available Rice produces a wide array of phytoalexins in response to pathogen attacks and UV-irradiation. Except for the flavonoid sakuranetin, most phytoalexins identified in rice are diterpenoid compounds. Analysis of phenolic-enriched fractions from UV-treated rice leaves showed that several phenolic compounds in addition to sakuranetin accumulated remarkably in rice leaves. We isolated two compounds from UV-treated rice leaves using silica gel column chromatography and preparative HPLC. The isolated phenolic compounds were identified as phenylamide compounds: N-trans-cinnamoyltryptamine and N-p-coumaroylserotonin. Expression analysis of biosynthetic genes demonstrated that genes for arylamine biosynthesis were upregulated by UV irradiation. This result suggested that phenylamide biosynthetic pathways are activated in rice leaves by UV treatment. To unravel the role of UV-induced phenylamides as phytoalexins, we examined their antimicrobial activity against rice fungal and bacterial pathogens. N-trans-Cinnamoyltryptamine inhibited the growth of rice brown spot fungus (Bipolaris oryzae. In addition to the known antifungal activity to the blast fungus, sakuranetin had antimicrobial activity toward B. oryzae and Rhizoctonia solani (rice sheath blight fungus. UV-induced phenylamides and sakuranetin also had antimicrobial activity against rice bacterial pathogens for grain rot (Burkholderia glumae, blight (Xanthomonas oryzae pv. oryzae and leaf streak (X. oryzae pv. oryzicola diseases. These findings suggested that the UV-induced phenylamides in rice are phytoalexins against a diverse array of pathogens.

  4. Avian Antimicrobial Host Defense Peptides: From Biology to Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Guolong Zhang

    2014-02-01

    Full Text Available Host defense peptides (HDPs are an important first line of defense with antimicrobial and immunomoduatory properties. Because they act on the microbial membranes or host immune cells, HDPs pose a low risk of triggering microbial resistance and therefore, are being actively investigated as a novel class of antimicrobials and vaccine adjuvants. Cathelicidins and β-defensins are two major families of HDPs in avian species. More than a dozen HDPs exist in birds, with the genes in each HDP family clustered in a single chromosomal segment, apparently as a result of gene duplication and diversification. In contrast to their mammalian counterparts that adopt various spatial conformations, mature avian cathelicidins are mostly α-helical. Avian β-defensins, on the other hand, adopt triple-stranded β-sheet structures similar to their mammalian relatives. Besides classical β-defensins, a group of avian-specific β-defensin-related peptides, namely ovodefensins, exist with a different six-cysteine motif. Like their mammalian counterparts, avian cathelicidins and defensins are derived from either myeloid or epithelial origin expressed in a majority of tissues with broad-spectrum antibacterial and immune regulatory activities. Structure-function relationship studies with several avian HDPs have led to identification of the peptide analogs with potential for use as antimicrobials and vaccine adjuvants. Dietary modulation of endogenous HDP synthesis has also emerged as a promising alternative approach to disease control and prevention in chickens.

  5. Study of the nanomaterials and their antimicrobial activities

    Science.gov (United States)

    Ramadi, Muntaha

    In the last decade, the world faced huge problems associated with the spread of antimicrobial resistant infections that are essentially untreatable such as methicillin resistant Staphylococcus aureus (MRSA) infection. These infections have begun to occur in both hospital and community environments. Developing new antimicrobial surface coatings can hold a great promise to minimize and control various problems that associated with the spreading of infections and biofilms formation, these coatings can be used in medicine where medical devices associated with severe infections, in construction industry and the in food packaging industry. It has been established that single-walled CNTs exhibit a strong antimicrobial activity and can pierce bacterial cell walls. Recently, nanomaterial structures that made from pure carbon such as CNTs have been seen as promising candidates for many potential applications in Biotechnology and bioscience due to the combination of their extraordinary properties that arise from surface area, light weight, strength, flexibility, unique electrical conductivity and many more novel physical and chemical properties at nanoscale level. CNTs have been used widely in biomedical field including drug delivery, gene therapy and creating new biomedical devices with novel properties. Researchers have now made a first step to add carbon nanotubes to antimicrobial agents list. There are two types of CNTs have been used in biomedical research. The first one is a single-walled carbon nanotube (SWNT) and the second is a multi-walled carbon nanotube (MWNT). Recent in vitro studies suggest that carbon nanotubes have antimicrobial activity and coating CNTs with nickel nanoparticle could enhance the antimicrobial activity of cabon nanotubes. In order to test this hypothesis, nickel nanoparticles were deposited on carbon nanotubes (CNTs) by electrochemical deposition. The carbon nanotubes used in this study were XD-CNTs, SWNTs and Ni-coated CNTs. The structure and

  6. Molecular cloning, expression and in vitro analysis of soluble cationic synthetic antimicrobial peptide from salt-inducible Escherichia coli GJ1158

    Directory of Open Access Journals (Sweden)

    Jawahar Babu Peravali

    2013-01-01

    Full Text Available Antimicrobial peptides are the upcoming therapeutic molecules as alternative drugs to the existing antibiotics owing to their potent action against pathogenic microorganisms. In this study, to obtain an antimicrobial peptide with a broad range of activity, the synthetic cationic antimicrobial peptide was designed by using in silico tools viz., antimicrobial peptide database, protparam, hierarchical neural network. Later, the peptide was translated back into a core nucleotide sequence and the gene for the peptide was constructed by overlapping PCR. The amplified gene was cloned into pRSET–A vector and transformed into salt inducible expression host E. coli GJ1158. The expression results show high yields of soluble recombinant fusion peptide (0.52 g/L from salt-inducible E. coli. The recombinant peptide was purified by the IMAC purification system and cleaved by enterokinase. The digested product was further purified and 0.12 g/L of biologically active recombinant cationic antimicrobial peptide was obtained. In vitro analysis of the purified peptide demonstrated high antimicrobial activity against both Gram positive and Gram negative bacteria devoid of hemolytic activity. Therefore, this synthetic cationic antimicrobial peptide could serves as an promising agent over chemical antibiotics. In this study, a synthetic cationic antimicrobial peptide was designed, cloned and expressed from salt-inducible E. coli GJ1158 using cost effective media in the large scale production of antimicrobial peptide and its biological activity was analysed against different Gram positive and negative organisms.

  7. Detection of a New cfr-Like Gene, cfr(B), in Enterococcus faecium Isolates Recovered from Human Specimens in the United States as Part of the SENTRY Antimicrobial Surveillance Program.

    Science.gov (United States)

    Deshpande, Lalitagauri M; Ashcraft, Deborah S; Kahn, Heather P; Pankey, George; Jones, Ronald N; Farrell, David J; Mendes, Rodrigo E

    2015-10-01

    Two linezolid-resistant Enterococcus faecium isolates (MICs, 8 μg/ml) from unique patients of a medical center in New Orleans were included in this study. Isolates were initially investigated for the presence of mutations in the V domain of 23S rRNA genes and L3, L4, and L22 ribosomal proteins, as well as cfr. Isolates were subjected to pulsed-field gel electrophoresis (just one band difference), and one representative strain was submitted to whole-genome sequencing. Gene location was also determined by hybridization, and cfr genes were cloned and expressed in a Staphylococcus aureus background. The two isolates had one out of six 23S rRNA alleles mutated (G2576T), had wild-type L3, L4, and L22 sequences, and were positive for a cfr-like gene. The sequence of the protein encoded by the cfr-like gene was most similar (99.7%) to that found in Peptoclostridium difficile, which shared only 74.9% amino acid identity with the proteins encoded by genes previously identified in staphylococci and non-faecium enterococci and was, therefore, denominated Cfr(B). When expressed in S. aureus, the protein conferred a resistance profile similar to that of Cfr. Two copies of cfr(B) were chromosomally located and embedded in a Tn6218 similar to the cfr-carrying transposon described in P. difficile. This study reports the first detection of cfr genes in E. faecium clinical isolates in the United States and characterization of a new cfr variant, cfr(B). cfr(B) has been observed in mobile genetic elements in E. faecium and P. difficile, suggesting potential for dissemination. However, further analysis is necessary to access the resistance levels conferred by cfr(B) when expressed in enterococci.

  8. A brief multi-disciplinary review on antimicrobial resistance in medicine and its linkage to the global environmental microbiota

    Directory of Open Access Journals (Sweden)

    Leon eCantas

    2013-05-01

    Full Text Available The discovery and introduction of antimicrobial agents to clinical medicine was one of the greatest medical triumphs of the 20th century that revolutionized the treatment of bacterial infections. However, the gradual emergence of populations of antimicrobial-resistant pathogenic bacteria resulting from use, misuse and abuse of antimicrobials has today become a major global health concern. Antimicrobial resistance genes have been suggested to originate from environmental bacteria, as clinically relevant resistance genes have been detected on the chromosome of environmental bacteria. As only a few new antimicrobials have been developed in the last decade, the further evolution of resistance poses a serious threat to public health. Urgent measures are required not only to minimize the use of antimicrobials for prophylactic and therapeutic purposes but also to look for alternative strategies for the control of bacterial infections. This review examines the global picture of antibacterial resistance, factors that favor its spread, strategies and limitations for its control and the need for continuous training of all stake-holders i.e. medical, veterinary, public health and other relevant professionals as well as human consumers of antibiotic drugs, in the appropriate use of antimicrobials.

  9. Differential expression of antimicrobial peptides in active and latent tuberculosis and its relationship with diabetes mellitus.

    Science.gov (United States)

    Gonzalez-Curiel, Irma; Castañeda-Delgado, Julio; Lopez-Lopez, Nallely; Araujo, Zaida; Hernandez-Pando, Rogelio; Gandara-Jasso, Benjamin; Macias-Segura, Noe; Enciso-Moreno, Antonio; Rivas-Santiago, Bruno

    2011-08-01

    Tuberculosis (TB) is one of the most important infectious diseases, causing 1.8 million deaths annually worldwide. This problem has increased because of the association with human immmunodeficiency virus and diabetes mellitus type 2, mainly in developing countries. In the past few years it has been highlighted the significance of antimicrobial peptides in the immunopathogenesis of TB ex vivo and in experimental models studies. In this study we analyzed the expression of CAMP, DEFA1, DEFB4, and DEFB103A in patients with latent TB and progressive TB with and without comorbidity with diabetes mellitus type 2. Antimicrobial peptide gene expression increased during progressive TB, which could be used as a biomarker for reactivation. By contrast, patients with diabetes mellitus type 2 have lower antimicrobial peptides gene expression, suggesting that the lack of its proper production in these patients contribute to enhance the risk for TB reactivation.

  10. Antimicrobial-Resistant Enterococci in Animals and Meat: A Human Health Hazard?

    DEFF Research Database (Denmark)

    Hammerum, A.M.; Lester, C.H.; Heuer, Ole Eske

    2010-01-01

    Enterococcus faecium and Enterococcus faecalis belong to the gastrointestinal flora of humans and animals. Although normally regarded harmless commensals, enterococci may cause a range of different infections in humans, including urinary tract infections, sepsis, and endocarditis. The use...... clones predominate in certain animal species. This may suggest that antimicrobial-resistant E. faecium from animals could be regarded less hazardous to humans; however, due to their excellent ability to acquire and transfer resistance genes, E. faecium of animal origin may act as donors of antimicrobial...... resistance genes for other more virulent enterococci. For E. faecalis, the situation appears different, as similar clones of, for example, vancomycin-and gentamicin-resistant E. faecalis have been obtained from animals and from human patients. Continuous surveillance of antimicrobial resistance...

  11. Cholic acid derivatives: novel antimicrobials.

    Science.gov (United States)

    Savage, P B; Li, C

    2000-02-01

    Mimics of squalamine and polymyxin B (PMB) have been prepared from cholic acid in hope of finding new antimicrobial agents. The squalamine mimics include the polyamine and sulphate functionalities found in the parent antibiotic, however, the positions relative to the steroid nucleus have been exchanged. The PMB mimics include the conservation of functionality among the polymyxin family of antibiotics, the primary amine groups and a hydrophobic chain. Although the squalamine and PMB mimics are morphologically dissimilar, they display similar activities. Both are simple to prepare and demonstrate broad spectrum antimicrobial activity against Gram-negative and Gram-positive organisms. Specific examples may be inactive alone, yet effectively permeabilise the outer membranes of Gram-negative bacteria rendering them sensitive to hydrophobic antibiotics. Problems associated with some of the squalamine and PMB mimics stem from their haemolytic activity and interactions with serum proteins, however, examples exist without these side effects which can sensitise Gram-negative bacteria to hydrophobic antibiotics.

  12. Antimicrobial Activity of Commercial Nanoparticles

    Science.gov (United States)

    Gajjar, Priyanka; Pettee, Brian; Britt, David W.; Huang, Wenjie; Johnson, William P.; Anderson, Anne J.

    2009-07-01

    Engineered nanoparticles are finding increased use in applications ranging from biosensors to prophylactic antimicrobials embedded in socks. The release of heavy metal-containing nanoparticles (NP) into the environment may be harmful to the efficacy of beneficial microbes that function in element cycling, pollutant degradation, and plant growth. Antimicrobial activity of commercial NP of Ag, CuO, and ZnO is demonstrated here against the beneficial soil microbe, Pseudomonas putida KT2440, which was modified to serve as a bioluminescent sentinel organism. "As manufactured" preparations of nano- Ag, -CuO, and -ZnO caused rapid, dose dependent loss of light output in the biosensor. Bulk equivalents of these products showed no inhibitory activity, indicating that particle size was determinant in activity.

  13. APD: the Antimicrobial Peptide Database.

    Science.gov (United States)

    Wang, Zhe; Wang, Guangshun

    2004-01-01

    An antimicrobial peptide database (APD) has been established based on an extensive literature search. It contains detailed information for 525 peptides (498 antibacterial, 155 antifungal, 28 antiviral and 18 antitumor). APD provides interactive interfaces for peptide query, prediction and design. It also provides statistical data for a select group of or all the peptides in the database. Peptide information can be searched using keywords such as peptide name, ID, length, net charge, hydrophobic percentage, key residue, unique sequence motif, structure and activity. APD is a useful tool for studying the structure-function relationship of antimicrobial peptides. The database can be accessed via a web-based browser at the URL: http://aps.unmc.edu/AP/main.html.

  14. Antimicrobial peptides in the brain.

    Science.gov (United States)

    Su, Yanhua; Zhang, Kai; Schluesener, Hermann J

    2010-10-01

    Antimicrobial peptides (AMPs) are an evolutionarily conserved component of the innate immune system of many species. The brain is an immunologically privileged organ but can produce a robust immune response against pathogens and cell debris, promoting rapid and efficient clearance. AMPs may be critically involved in the innate immune system of the brain. Though the mechanisms of AMPs' action in the brain still need further elucidation, many studies have shown that AMPs are multifunctional molecules in the brain. In addition to antimicrobial action, they take part in congenital and adaptive immune reactions (immunoregulation), function as signaling molecules in tissue repair, inflammation and other important processes through different mechanisms, and they might, in addition, become diagnostic markers of brain disease.

  15. 检测家蝇抗菌肽基因diptericin时间表达模式的实时荧光定量方法的建立%Establishing Real-time Quantitative PCR Assay for Detecting Expression Pattern of The Antimicrobial Peptide gene Diptericin from the Musca domestica

    Institute of Scientific and Technical Information of China (English)

    杨小蓉; 金小宝; 朱家勇; 丁彩屏

    2012-01-01

    OBJECTIVE To establish a fluorescent dye (SYBR Green I) real-time quantitative PCR (real-timePCR) to detect antimicrobial peptide gene diptericin expression patterns method from Musca domestica. METHODS Based on the cloned diptericin gene, software Prmier 5.0 was used for designing primers for non-induced, different developmental stages and different times (2h, 4h, 8h, 12h, 24h, 36h and 48h) of Musca domestica were induced by real-time PCR. 10 times of serial dilution of plasmid with target gene was used. Real-time PCR was used for standard curve. RESULTS The gene expression level that Uninduced third-instar was low compared with that induced. The greatest level of mRNA for all nine infection time was in 12 hours. After induced 2 hours, a significantly transcript level 107 was reflected. After 36 hours, mRNA levels were significantly descend. In different stages of development, the greatest level of mRNA for all six stages was in the 3rd- instars and adult. The lowest level of transcript detected was in the eggs and 1st- instars. A 102 -fold increased in mRNA was revealed between the 3rd- and eggs, 1st-, 2nd- instar and pupae. Almost no change was found between the 3rd- instar and adult. CONCLUSION Real-time PCR detection method housefly gene diptericin specificity, high sensitivity, in order to further explore the biological activity of antimicrobial peptides housefly to the study of new antibiotics to lay the initial foundation.%目的 建立荧光染料(SYBR Green Ⅰ)实时荧光定量PCR(real-timePCR)方法检测的家蝇抗菌肽基因diptericin 时间表达模式方法.方法 基于已克隆出的diptericin基因,利用软件Prmier5.0设计上下游引物,对未诱导,诱导后2h、4h、8h、12 h、24 h、36 h、48 h及不同发育阶段的家蝇三龄幼虫进行real-time PCR设计引物,然后利用10倍系列稀释含有目的基因的质粒,进行实时荧光定量PCR反应,制作标准曲线.结果 未刺激的三龄幼虫diptericin基因

  16. A European study on the relationship between antimicrobial use and antimicrobial resistance

    NARCIS (Netherlands)

    Bronzwaer, SLAM; Cars, O; Buchholz, U; Molstad, S; Goettsch, W; Veldhuijzen, IK; Kool, JL; Sprenger, MJW; Degener, JE

    2002-01-01

    In Europe, antimicrobial resistance has been monitored since 1998 by the European Antimicrobial Resistance Surveillance System (EARSS). We examined the relationship between penicillin nonsusceptibility of invasive isolates of Streptococcus pneumoniae and antibiotic sales. Information was collected o

  17. Antimicrobial activities of squalamine mimics.

    OpenAIRE

    1997-01-01

    We investigated the antimicrobial properties of compounds with structural features that were designed to mimic those of squalamine, an antibiotic isolated from the stomach of the dogfish shark. The mimics, like squalamine, are sterol-polyamine conjugates. Unlike squalamine, the mimics were simple to prepare, at high yield, from readily available starting materials. Several squalamine mimics showed activity against gram-negative rods, gram-positive cocci including methicillin-resistant Staphyl...

  18. Antimicrobial resistance: a global response.

    OpenAIRE

    Smith, R.; Coast, J.

    2002-01-01

    Resistance to antimicrobial therapies reduces the effectiveness of these drugs, leading to increased morbidity, mortality, and health care expenditure. Because globalization increases the vulnerability of any country to diseases occurring in other countries, resistance presents a major threat to global public health, and no country acting on its own can adequately protect the health of its population against it. International collective action is therefore essential. Nevertheless, responsibil...

  19. APD: the Antimicrobial Peptide Database

    OpenAIRE

    Wang, Zhe; Wang, Guangshun

    2004-01-01

    An antimicrobial peptide database (APD) has been established based on an extensive literature search. It contains detailed information for 525 peptides (498 antibacterial, 155 antifungal, 28 antiviral and 18 antitumor). APD provides interactive interfaces for peptide query, prediction and design. It also provides statistical data for a select group of or all the peptides in the database. Peptide information can be searched using keywords such as peptide name, ID, length, net charge, hydrophob...

  20. Antimicrobial stewardship in wound care

    DEFF Research Database (Denmark)

    Lipsky, Benjamin A; Dryden, Matthew; Gottrup, Finn

    2016-01-01

    of experts in infectious diseases/clinical microbiology (from the British Society for Antimicrobial Chemotherapy) and wound management (from the European Wound Management Association) who, after thoroughly reviewing the available literature and holding teleconferences, jointly produced this guidance document...... be as narrowly focused, and administered for the shortest duration, as possible. AMS teams should be interdisciplinary, especially including specialists in infection and pharmacy, with input from administrative personnel, the treating clinicians and their patients. CONCLUSIONS: Available evidence is limited...

  1. Antimicrobial hydrogels for the treatment of infection.

    Science.gov (United States)

    Veiga, Ana Salomé; Schneider, Joel P

    2013-11-01

    The increasing prevalence of microbial infections, especially those associated with impaired wound healing and biomedical implant failure has spurred the development of new materials having antimicrobial activity. Hydrogels are a class of highly hydrated material finding use in diverse medical applications such as drug delivery, tissue engineering, as wound fillers, and as implant coatings, to name a few. The biocompatible nature of many gels make them a convenient starting platform to develop selectively active antimicrobial materials. Hydrogels with antimicrobial properties can be obtained through the encapsulation or covalent immobilization of known antimicrobial agents, or the material itself can be designed to possess inherent antimicrobial activity. In this review we present an overview of antimicrobial hydrogels that have recently been developed and when possible provide a discussion relevant to their mechanism of action.

  2. Antimicrobial polymer films for food packaging

    Science.gov (United States)

    Concilio, S.; Piotto, S.; Sessa, L.; Iannelli, P.; Porta, A.; Calabrese, E. C.; Galdi, M. R.; Incarnato, L.

    2012-07-01

    New antimicrobial polymeric systems were realized introducing new antimicrobial azo compounds in PP and LDPE matrices. The polymeric materials containing different percentage of azo compounds were mold-casted and the obtained film were tested in vitro against Gram+ and Gram- bacteria and fungi. These results hold promise for the fabrication of bacteria-resistant polymer films by means of simple melt processing with antimicrobial azo-dyes.

  3. Antimicrobial technology in orthopedic and spinal implants

    Science.gov (United States)

    Eltorai, Adam EM; Haglin, Jack; Perera, Sudheesha; Brea, Bielinsky A; Ruttiman, Roy; Garcia, Dioscaris R; Born, Christopher T; Daniels, Alan H

    2016-01-01

    Infections can hinder orthopedic implant function and retention. Current implant-based antimicrobial strategies largely utilize coating-based approaches in order to reduce biofilm formation and bacterial adhesion. Several emerging antimicrobial technologies that integrate a multidisciplinary combination of drug delivery systems, material science, immunology, and polymer chemistry are in development and early clinical use. This review outlines orthopedic implant antimicrobial technology, its current applications and supporting evidence, and clinically promising future directions. PMID:27335811

  4. Insect inducible antimicrobial peptides and their applications.

    Science.gov (United States)

    Ezzati-Tabrizi, Reyhaneh; Farrokhi, Naser; Talaei-Hassanloui, Reza; Alavi, Seyed Mehdi; Hosseininaveh, Vahid

    2013-12-01

    Antimicrobial peptides (AMPs) are found as important components of the innate immune system (host defense) of all invertebrates. These peptides can be constitutively expressed or induced in response to microbial infections. Indeed, they vary in their amino acid sequences, potency and antimicrobial activity spectra. The smaller AMPs act greatly by disrupting the structure or function of microbial cell membranes. Here, the insect innate immune system with emphasis on inducible antimicrobial peptide properties against microbial invaders has been discussed.

  5. Identification and Antimicrobial Activity Detection of Lactic Acid Bacteria Isolated from Corn Stover Silage

    Science.gov (United States)

    Li, Dongxia; Ni, Kuikui; Pang, Huili; Wang, Yanping; Cai, Yimin; Jin, Qingsheng

    2015-01-01

    A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC 43971T, Micrococcus luteus ATCC 4698T and Escherichia coli ATCC 11775T were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at 100°C), but the antimicrobial activity was eliminated after treatment at 121°C for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory. PMID:25924957

  6. Identification and antimicrobial activity detection of lactic Acid bacteria isolated from corn stover silage.

    Science.gov (United States)

    Li, Dongxia; Ni, Kuikui; Pang, Huili; Wang, Yanping; Cai, Yimin; Jin, Qingsheng

    2015-05-01

    A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC 43971(T), Micrococcus luteus ATCC 4698(T) and Escherichia coli ATCC 11775(T) were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at 100°C), but the antimicrobial activity was eliminated after treatment at 121°C for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory.

  7. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture.

    Science.gov (United States)

    Noor Uddin, Gazi Md; Larsen, Marianne Halberg; Christensen, Henrik; Aarestrup, Frank M; Phu, Tran Minh; Dalsgaard, Anders

    2015-01-01

    Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic antimicrobial resistance and associated transferable resistance genes. The bacterial species was established by 16S rRNA sequence analysis of 125 representative bacterial isolates. MIC testing was done for a range of antimicrobials and whole genome sequencing of six multiple antimicrobial resistant Bacillus spp. used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have missed a few bacterial species present in the tested products this would represent minor bias, but future studies may apply culture independent identification methods like pyro sequencing. Only 6/60 isolates were resistant to more than four antimicrobials and whole genome sequencing showed that they contained macrolide (ermD), tetracycline (tetL), phenicol (fexA) and trimethoprim (dfrD, dfrG and dfrK) resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers of resistance genes compared to the naturally occurring bacterial species in aquaculture environments. Approval procedures of probiotic products must be strengthened

  8. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture.

    Directory of Open Access Journals (Sweden)

    Gazi Md Noor Uddin

    Full Text Available Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic antimicrobial resistance and associated transferable resistance genes. The bacterial species was established by 16S rRNA sequence analysis of 125 representative bacterial isolates. MIC testing was done for a range of antimicrobials and whole genome sequencing of six multiple antimicrobial resistant Bacillus spp. used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have missed a few bacterial species present in the tested products this would represent minor bias, but future studies may apply culture independent identification methods like pyro sequencing. Only 6/60 isolates were resistant to more than four antimicrobials and whole genome sequencing showed that they contained macrolide (ermD, tetracycline (tetL, phenicol (fexA and trimethoprim (dfrD, dfrG and dfrK resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers of resistance genes compared to the naturally occurring bacterial species in aquaculture environments. Approval procedures of probiotic products must be

  9. Antimicrobial activity of Gymnema sylvestre leaf extract.

    Science.gov (United States)

    Satdive, R K; Abhilash, P; Fulzele, Devanand P

    2003-12-01

    The ethanolic extract of Gymnema sylvestre leaves demonstrated antimicrobial activity against Bacillus pumilis, B. subtilis, Pseudomonas aeruginosa and Staphylococcus aureus and inactivity against Proteus vulgaris and Escherichia coli.

  10. Synthesis of Aminolaurylpyridinium Chloride as Antimicrobial Agent

    Institute of Scientific and Technical Information of China (English)

    ZHAO Tao; SONG Xin-yuan; SUN Gang

    2008-01-01

    4-amino-laurylpyridinium chloride (ALPC) was synthesized and employed in antimicrobial finishing of wool fabrics. The structures of the salt was fully characterized by using FTIR, 1 H-NMR and 13 C-NMR analysis. The effects of pH conditions of finishing baths, finishing time and temperature, and salt concentrations were investigated. ALPC could form ionic interactions with anionic groups on wool, which contribute to durable antimicrobial functions. The finished wool fabrics exhibited antimicrobial efficacy against Escherichia coli. The washing durability of antimicrobial functions on the finished wool fabrics was also studied.

  11. Antimicrobial use in food and companion animals.

    Science.gov (United States)

    Prescott, John F

    2008-12-01

    The vast literature on antimicrobial drug use in animals has expanded considerably recently as the antimicrobial resistance (AMR) crisis in human medicine leads to questions about all usage of antimicrobial drugs, including long-term usage in intensively managed food animals for growth promotion and disease prevention. Attention is also increasingly focusing on antimicrobial use and on bacterial resistance in companion animals, which are in intimate contact with the human population. They may share resistant bacteria with their owners, amplify resistant bacteria acquired from their owners, and act as a reservoir for human infection. Considerable effort is being made to describe the basis of AMR in bacterial pathogens of animals. Documentation of many aspects of use of antimicrobials in animals is, however, generally less developed and only a few countries can describe quantities of drugs used in animals to kg levels annually. In recent years, many national veterinary associations have produced 'prudent use guidelines' to try to improve antimicrobial drug use and decrease resistance, but the impact of guidelines is unknown. Within the evolving global movement for 'antimicrobial stewardship', there is considerable scope to improve many aspects of antimicrobial use in animals, including infection control and reduction of use, with a view to reducing resistance and its spread, and to preserving antimicrobial drugs for the future.

  12. Phenotypic and genotypic characteristics of antimicrobial resistant Escherichia coli isolated from symbovine flies, cattle and sympatric insectivorous house martins from a farm in the Czech Republic (2006-2007).

    Science.gov (United States)

    Rybaríková, Jana; Dolejská, Monika; Materna, David; Literák, Ivan; Cízek, Alois

    2010-10-01

    The prevalence of antimicrobial resistant Escherichia coli was tested in symbovine flies and sympatric house martins (Delichon urbica) at a dairy farm. Antimicrobial resistant E. coli was detected in 89% (n=147) of isolates from flies within a calf barn. Isolates with the same antimicrobial resistance phenotypes, genes, and pulsotypes were found between both fly and calf E. coli isolates, suggesting that the calves were the initial source of the antimicrobial resistant strains in fly isolates. Symbovine flies were considered as important reservoirs of antimicrobial resistant E. coli strains at a dairy farm, due to their intensive contact with cattle feces and manure. House martin fecal samples from the same farm contained 4.5% (n=393) of antimicrobial resistant E. coli. House martin isolates displayed different macrorestriction profiles than fly isolates and the significance of house martins as a reservoir and vector of antimicrobial resistant E. coli appears low.

  13. A systems biology approach to investigate the antimicrobial activity of oleuropein

    Science.gov (United States)

    Oleuropein and its hydrolysis products are olive phenolic compounds that have antimicrobial effects on a variety of pathogens, with the potential to be utilized in food and pharmaceutical products. While the existing research is mainly focused on individual genes or enzymes that are regulated by ole...

  14. [High expression of antimicrobial peptide Cecropin AD in Escherichia coli by fusion with EDDIE].

    Science.gov (United States)

    Zhang, Zhen; Ke, Tao; Zhou, Yuling; Ma, Xiangdong; Ma, Lixin

    2009-08-01

    In this study, we efficiently expressed the active antimicrobial peptide (CAD), which fused with the site-mutated coat protein (EDDIE) of the classical swine fever virus, in Escherichia coli. First, we obtained the e-cad fusion gene from the CAD gene and the EDDIE gene using overlapping PCR. Then to get the recombinant expression vector (pETED), the e-cad fusion gene was cloned into the pET30a vector by a site-directed homologous recombination technique. The EDDIE-CAD fusion protein expressed in E. coli as inclusion bodies, and its yield was more than 40% of total bacterial proteins. After renaturated in vitro and self-cleavage of the fusion protein, we obtained the antimicrobial peptide Cecropin AD. Antimicrobial experiments showed that the Cecropin AD efficiently inhibited the growth of G+ and G- bacteria, but it weakly inhibited the growth of Saccharomyces. This method provides an excellent way for high expression of antimicrobial peptides when fused with EDDIE.

  15. Antimicrobial resistance in zoonotic nontyphoidal Salmonella: an alarming trend?

    Science.gov (United States)

    Michael, G B; Schwarz, S

    2016-12-01

    Zoonotic bacteria of the genus Salmonella have acquired various antimicrobial resistance properties over the years. The corresponding resistance genes are commonly located on plasmids, transposons, gene cassettes, or variants of the Salmonella Genomic Islands SGI1 and SGI2. Human infections by nontyphoidal Salmonella isolates mainly result from ingestion of contaminated food. The two predominantly found Salmonella enterica subsp. enterica serovars in the USA and in Europe are S. Enteritidis and S. Typhimurium. Many other nontyphoidal Salmonella serovars have been implicated in foodborne Salmonella outbreaks. Summary reports of the antimicrobial susceptibility patterns of nontyphoidal Salmonella isolates over time suggest a moderate to low level of antimicrobial resistance and multidrug-resistance. However, serovar-specific analyses showed in part a steady state, a continuous decline, or a recent increase in resistance to certain antimicrobial agents. Resistance to critically important antimicrobial agents, e.g. third-generation cephalosporins and (fluoro)quinolones is part of many monitoring programmes and the corresponding results confirm that extended-spectrum β-lactamases are still rarely found in nontyphoidal Salmonella serovars, whereas resistance to (fluoro)quinolones is prevalent at variable frequencies among different serovars from humans and animals in different countries. Although it is likely that nontyphoidal Salmonella isolates from animals represent a reservoir for resistance determinants, it is mostly unknown where and when Salmonella isolates acquired resistance properties and which exchange processes have happened since then.

  16. Antimicrobial effectors in the nematode Caenorhabditis elegans: an outgroup to the Arthropoda.

    Science.gov (United States)

    Dierking, Katja; Yang, Wentao; Schulenburg, Hinrich

    2016-05-26

    Nematodes and arthropods likely form the taxon Ecdysozoa. Information on antimicrobial effectors from the model nematode Caenorhabditis elegans may thus shed light on the evolutionary origin of these defences in arthropods. This nematode species possesses an extensive armory of putative antimicrobial effector proteins, such as lysozymes, caenopores (or saposin-like proteins), defensin-like peptides, caenacins and neuropeptide-like proteins, in addition to the production of reactive oxygen species and autophagy. As C. elegans is a bacterivore that lives in microbe-rich environments, some of its effector peptides and proteins likely function in both digestion of bacterial food and pathogen elimination. In this review, we provide an overview of C. elegans immune effector proteins and mechanisms. We summarize the experimental evidence of their antimicrobial function and involvement in the response to pathogen infection. We further evaluate the microbe-induced expression of effector genes using WormExp, a recently established database for C. elegans gene expression analysis. We emphasize the need for further analysis at the protein level to demonstrate an antimicrobial activity of these molecules both in vitro and in vivoThis article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.

  17. Antimicrobial resistance in Enterococcus strains isolated from healthy domestic dogs.

    Science.gov (United States)

    Bertelloni, Fabrizio; Salvadori, Claudia; Lotti, Giulia; Cerri, Domenico; Ebani, Valentina Virginia

    2016-12-15

    Enterococci are opportunistic bacteria that cause severe infections in animals and humans, capable to acquire, express, and transfer antimicrobial resistance. Susceptibility to 21 antimicrobial agents was tested by the disk diffusion method in 222 Enterococcus spp. strains isolated from the fecal samples of 287 healthy domestic dogs. Vancomycin and ampicillin minimum inhibitory concentrations (MICs) and high-level aminoglycoside resistance (HLAR) tests were also performed. Isolates showed resistance mainly to streptomycin (88.7%), neomycin (80.6%), and tetracycline (69.4%). Forty-two (18.9%) isolates showed an HLAR to streptomycin and 15 (6.7%) to gentamicin. Vancomycin and ampicillin MIC values showed 1 and 18 resistant strains, respectively. One hundred and thirty-six (61.2%) strains were classified as multidrug resistant and six (2.7%) strains as possibly extensively drug-resistant bacteria. Enterococcus faecium and Enterococcus faecalis were the most prevalent antimicrobial resistant species. Companion animals, which often live in close contact with their owners and share the same environment, represent a serious source of enterococci resistant to several antibiotics; for this reason, they may be a hazard for public health by providing a conduit for the entrance of resistance genes into the community.

  18. Antimicrobial peptides: key components of the innate immune system.

    Science.gov (United States)

    Pasupuleti, Mukesh; Schmidtchen, Artur; Malmsten, Martin

    2012-06-01

    Life-threatening infectious diseases are on their way to cause a worldwide crisis, as treating them effectively is becoming increasingly difficult due to the emergence of antibiotic resistant strains. Antimicrobial peptides (AMPs) form an ancient type of innate immunity found universally in all living organisms, providing a principal first-line of defense against the invading pathogens. The unique diverse function and architecture of AMPs has attracted considerable attention by scientists, both in terms of understanding the basic biology of the innate immune system, and as a tool in the design of molecular templates for new anti-infective drugs. AMPs are gene-encoded short (antimicrobial activity. AMPs have been the subject of natural evolution, as have the microbes, for hundreds of millions of years. Despite this long history of co-evolution, AMPs have not lost their ability to kill or inhibit the microbes totally, nor have the microbes learnt to avoid the lethal punch of AMPs. AMPs therefore have potential to provide an important breakthrough and form the basis for a new class of antibiotics. In this review, we would like to give an overview of cationic antimicrobial peptides, origin, structure, functions, and mode of action of AMPs, which are highly expressed and found in humans, as well as a brief discussion about widely abundant, well characterized AMPs in mammals, in addition to pharmaceutical aspects and the additional functions of AMPs.

  19. Occurrence of integrons and resistance genes among sulphonamide-resistant Shigella spp. from Brazil

    DEFF Research Database (Denmark)

    Peirano, G.; Agersø, Yvonne; Aarestrup, Frank Møller

    2005-01-01

    Objectives: To determine the occurrence of class 1 and 2 integrons and antimicrobial resistance genes among sulphonamide-resistant Shigella strains isolated in Brazil during 1999-2003. Methods: Sixty-two Shigella (Shigella flexneri, n = 47 and Shigella sonnei, n = 15) were tested against 21....... Conclusions: The detection of class 1 and 2 integrons and additional antimicrobial resistance genes allowed us to identify the most frequent antimicrobial resistance patterns of Shigella spp. isolated in Brazil....

  20. Antimicrobial Susceptibility of Autochthonous Aquatic Vibrio cholerae in Haiti

    Science.gov (United States)

    Baron, Sandrine; Lesne, Jean; Jouy, Eric; Larvor, Emeline; Kempf, Isabelle; Boncy, Jacques; Rebaudet, Stanilas; Piarroux, Renaud

    2016-01-01

    We investigated the antimicrobial susceptibility of 50 environmental isolates of Vibrio cholerae non-O1/non-O139 collected in surface waters in Haiti in July 2012, during an active cholera outbreak. A panel of 16 antibiotics was tested on the isolates using the disk diffusion method and PCR detection of seven resistance-associated genes (strA/B, sul1/2, ermA/B, and mefA). All isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, imipenem, ciprofloxacin, norfloxacin, amikacin, and gentamicin. Nearly a quarter (22.0%) of the isolates were susceptible to all 16 antimicrobials tested and only 8.0% of the isolates (n = 4) were multidrug-resistant. The highest proportions of resistant isolates were observed for sulfonamide (70.0%), amoxicillin (12.0%), and trimethoprim-sulfamethoxazole (10.0%). One strain was resistant to erythromycin and one to doxycycline, two antibiotics used to treat cholera in Haiti. Among the 50 isolates, 78% possessed at least two resistance-associated genes, and the genes sul1, ermA, and strB were detected in all four multidrug-resistant isolates. Our results clearly indicate that the autochthonous population of V. cholerae non-O1/non-O139 found in surface waters in Haiti shows antimicrobial patterns different from that of the outbreak strain. The presence in the Haitian aquatic environment of V. cholerae non-O1/non-O139 with reduced susceptibility or resistance to antibiotics used in human medicine may constitute a mild public health threat. PMID:27818656

  1. Participatory eHealth development to support nurses in antimicrobial stewardship

    NARCIS (Netherlands)

    Wentzel, Jobke; van Velsen, Lex; van Limburg, Maarten; de Jong, Nienke; Karreman, Joyce; Hendrix, Ron; van Gemert-Pi, Julia Elisabeth Wilhelmina Cornelia

    2014-01-01

    Background: Antimicrobial resistance poses a threat to patient safety worldwide. To stop antimicrobial resistance, Antimicrobial Stewardship Programs (ASPs; programs for optimizing antimicrobial use), need to be implemented. Within these programs, nurses are important actors, as they put antimicrobi

  2. The role of amphibian antimicrobial peptides in protection of amphibians from pathogens linked to global amphibian declines.

    Science.gov (United States)

    Rollins-Smith, Louise A

    2009-08-01

    Amphibian species have experienced population declines and extinctions worldwide that are unprecedented in recent history. Many of these recent declines have been linked to a pathogenic skin fungus, Batrachochytrium dendrobatidis, or to iridoviruses of the genus Ranavirus. One of the first lines of defense against pathogens that enter by way of the skin are antimicrobial peptides synthesized and stored in dermal granular glands and secreted into the mucus following alarm or injury. Here, I review what is known about the capacity of amphibian antimicrobial peptides from diverse amphibians to inhibit B. dendrobatidis or ranavirus infections. When multiple species were compared for the effectiveness of their in vitro antimicrobial peptides defenses against B. dendrobatidis, non-declining species of rainforest amphibians had more effective antimicrobial peptides than species in the same habitat that had recently experienced population declines. Further, there was a significant correlation between the effectiveness of the antimicrobial peptides and resistance of the species to experimental infection. These studies support the hypothesis that antimicrobial peptides are an important component of innate defenses against B. dendrobatidis. Some amphibian antimicrobial peptides inhibit ranavirus infections and infection of human T lymphocytes by the human immunodeficiency virus (HIV). An effective antimicrobial peptide defense against skin pathogens appears to depend on a diverse array of genes expressing antimicrobial peptides. The production of antimicrobial peptides may be regulated by signals from the pathogens. However, this defense must also accommodate potentially beneficial microbes on the skin that compete or inhibit growth of the pathogens. How this delicate balancing act is accomplished is an important area of future research.

  3. Antimicrobial resistance risk factors and characterisation of faecal E. coli isolated from healthy Labrador retrievers in the United Kingdom.

    Science.gov (United States)

    Schmidt, Vanessa M; Pinchbeck, Gina L; Nuttall, Tim; McEwan, Neil; Dawson, Susan; Williams, Nicola J

    2015-04-01

    Antimicrobial resistant bacteria are increasingly detected from canine samples but few studies have examined commensal isolates in healthy community dogs. We aimed to characterise faecal Escherichia coli from 73 healthy non-veterinarian-visiting and non-antimicrobial treated Labrador retrievers, recruited from dog shows in the North West United Kingdom between November 2010 and June 2011. Each enrolled dog provided one faecal sample for our study. E. coli were isolated from 72/73 (99%) faecal samples. Disc diffusion susceptibility tests were determined for a range of antimicrobials, including phenotypic extended-spectrum beta-lactamase (ESBL) and AmpC-production. PCR assay detected phylogenetic groups and resistance genes (blaCTX-M, blaSHV, blaTEM, blaOXA, blaCIT, qnr), and conjugation experiments were performed to investigate potential transfer of mobile genetic elements. Multivariable logistic regression examined potential risk factors from owner-questionnaires for the presence of antimicrobial resistant faecal E. coli. Antimicrobial resistant, multi-drug resistant (≥3 antimicrobial classes; MDR) and AmpC-producing E. coli were detected in 63%, 30% and 16% of samples, respectively. ESBL-producing E. coli was detected from only one sample and conjugation experiments found that blaCTX-M and blaCIT were transferred from commensal E. coli to a recipient strain. Most isolates were phylogenetic groups B1 and A. Group B2 isolates were associated with lower prevalence of resistance to at least one antimicrobial (PE. coli were surprisingly prevalent in this group of non-antimicrobial treated and non-veterinarian-visiting dogs and consumption of raw meat was a significant risk factor for antimicrobial resistance. These findings are of concern due to the increasing popularity of raw-meat canine diets, and the potential for opportunistic infection, zoonotic transmission and transmission of antimicrobial resistant determinants from commensal isolates to potential pathogenic

  4. ­Genomic data mining of the marine actinobacteria Streptomyces sp. H-KF8 unveils insights into multi-stress related genes and metabolic pathways involved in antimicrobial synthesis

    Directory of Open Access Journals (Sweden)

    Agustina Undabarrena

    2017-02-01

    Full Text Available Streptomyces sp. H-KF8 is an actinobacterial strain isolated from marine sediments of a Chilean Patagonian fjord. Morphological characterization together with antibacterial activity was assessed in various culture media, revealing a carbon-source dependent activity mainly against Gram-positive bacteria (S. aureus and L. monocytogenes. Genome mining of this antibacterial-producing bacterium revealed the presence of 26 biosynthetic gene clusters (BGCs for secondary metabolites, where among them, 81% have low similarities with known BGCs. In addition, a genomic search in Streptomyces sp. H-KF8 unveiled the presence of a wide variety of genetic determinants related to heavy metal resistance (49 genes, oxidative stress (69 genes and antibiotic resistance (97 genes. This study revealed that the marine-derived Streptomyces sp. H-KF8 bacterium has the capability to tolerate a diverse set of heavy metals such as copper, cobalt, mercury, chromate and nickel; as well as the highly toxic tellurite, a feature first time described for Streptomyces. In addition, Streptomyces sp. H-KF8 possesses a major resistance towards oxidative stress, in comparison to the soil reference strain Streptomyces violaceoruber A3(2. Moreover, Streptomyces sp. H-KF8 showed resistance to 88% of the antibiotics tested, indicating overall, a strong response to several abiotic stressors. The combination of these biological traits confirms the metabolic versatility of Streptomyces sp. H-KF8, a genetically well-prepared microorganism with the ability to confront the dynamics of the fjord-unique marine environment.

  5. ­Genomic data mining of the marine actinobacteria Streptomyces sp. H-KF8 unveils insights into multi-stress related genes and metabolic pathways involved in antimicrobial synthesis

    Science.gov (United States)

    Undabarrena, Agustina; Ugalde, Juan A.; Seeger, Michael

    2017-01-01

    Streptomyces sp. H-KF8 is an actinobacterial strain isolated from marine sediments of a Chilean Patagonian fjord. Morphological characterization together with antibacterial activity was assessed in various culture media, revealing a carbon-source dependent activity mainly against Gram-positive bacteria (S. aureus and L. monocytogenes). Genome mining of this antibacterial-producing bacterium revealed the presence of 26 biosynthetic gene clusters (BGCs) for secondary metabolites, where among them, 81% have low similarities with known BGCs. In addition, a genomic search in Streptomyces sp. H-KF8 unveiled the presence of a wide variety of genetic determinants related to heavy metal resistance (49 genes), oxidative stress (69 genes) and antibiotic resistance (97 genes). This study revealed that the marine-derived Streptomyces sp. H-KF8 bacterium has the capability to tolerate a diverse set of heavy metals such as copper, cobalt, mercury, chromate and nickel; as well as the highly toxic tellurite, a feature first time described for Streptomyces. In addition, Streptomyces sp. H-KF8 possesses a major resistance towards oxidative stress, in comparison to the soil reference strain Streptomyces violaceoruber A3(2). Moreover, Streptomyces sp. H-KF8 showed resistance to 88% of the antibiotics tested, indicating overall, a strong response to several abiotic stressors. The combination of these biological traits confirms the metabolic versatility of Streptomyces sp. H-KF8, a genetically well-prepared microorganism with the ability to confront the dynamics of the fjord-unique marine environment. PMID:28229018

  6. Chemical and genetic characterization of bacteriocins: antimicrobial peptides for food safety.

    Science.gov (United States)

    Snyder, Abigail B; Worobo, Randy W

    2014-01-15

    Antimicrobial peptides are produced across all domains of life. Among these diverse compounds, those produced by bacteria have been most successfully applied as agents of biocontrol in food and agriculture. Bacteriocins are ribosomally synthesized, proteinaceous compounds that inhibit the growth of closely related bacteria. Even within the subcategory of bacteriocins, the peptides vary significantly in terms of the gene cluster responsible for expression, and chemical and structural composition. The polycistronic gene cluster generally includes a structural gene and various combinations of immunity, secretion, and regulatory genes and modifying enzymes. Chemical variation can exist in amino acid identity, chain length, secondary and tertiary structural features, as well as specificity of active sites. This diversity posits bacteriocins as potential antimicrobial agents with a range of functions and applications. Those produced by food-grade bacteria and applied in normally occurring concentrations can be used as GRAS-status food additives. However, successful application requires thorough characterization.

  7. Shiva-1a基因在杆状病毒中的表达及其表达产物抑菌活性的检测%Expression of the Shiva-1a Gene in Recombinant Baculovirus System and Analysis of the Peptide Antimicrobial Activity

    Institute of Scientific and Technical Information of China (English)

    许丹; 许信刚; 王志昇; 闫东东; 童德文

    2011-01-01

    Based on the sequences of shiva-1a lytic peptide registered in GenBank, the fragment of the preferred codons of insect, shiva-1a gene sequence was designed and artificial synthesized, and then cloned into the pBacFast Dual vector of BAC-TO-BACTM recombinant baculovirus expression system.The recombinant plasmid was transformed into DH10Bac competent cell.By transfecting spodoptera fragiperda 9 (Sf-9) ceils with cellfectin and prepared recombinant bacmid, the recombinant baculovirus from the supernatant was obtained.PCR showed that the recombinant baculovirus was constructed successfully.Western blot showed that shiva-1a peptide with a molecular weight of 5 ku was expressed.In vitro antimicrobial test showed that shiva-1a antimicrobial had activity against E.coli.%根据GenBank上公布的shiva-1a的成熟肽基因序列,人工合成shiva-1a基因并加入6×His标签.将shiva-1a基因克隆到杆状病毒转座载体pBacFast-Dual中,筛选重组质粒,转化大肠杆菌DH10Bac感受态细胞,经蓝白斑筛选得到重组杆状病毒DNA,以脂质体介导法转染Sf-9昆虫细胞,待细胞出现病变后,收集上清液从而获得重组杆状病毒.用此杆状病毒感染的Sf-9细胞,Western blot检测出分子量约5 ku的shiva-1a多肽,与预期结果大小一致.体外抑菌试验证明,表达的shiva-1a多肽对大肠杆菌(DE3菌株)具有抑菌活性.

  8. Distribution of virulence determinants among antimicrobial-resistant and antimicrobial-susceptible Escherichia coli implicated in urinary tract infections

    Directory of Open Access Journals (Sweden)

    SAM Stephenson

    2016-01-01

    Full Text Available Introduction: Uropathogenic Escherichia coli (UPEC rely on the correlation of virulence expression with antimicrobial resistance to persist and cause severe urinary tract infections (UTIs. Objectives: We assessed the virulence pattern and prevalence among UPEC strains susceptible and resistant to multiple antimicrobial classes. Methods: A total of 174 non-duplicate UPEC strains from patients with clinically significant UTIs were analysed for susceptibility to aminoglycoside, antifolate, cephalosporin, nitrofuran and quinolone antibiotics for the production of extended-spectrum β-lactamases and for the presence of six virulence determinants encoding adhesins (afimbrial, Type 1 fimbriae, P and S-fimbriae and toxins (cytotoxic necrotising factor and haemolysin. Results: Relatively high resistance rates to nalidixic acid, ciprofloxacin, cephalothin and trimethoprim-sulfamethoxazole (82%, 78%, 62% and 59%, respectively were observed. Fourteen distinct patterns were identified for the virulence determinants such as afaBC, cnfI, fimH, hylA, papEF and sfaDE. The toxin gene, cnfI (75.3%, was the second most prevalent marker to the adhesin, fimH (97.1%. The significant association of sfaDE/hylA (P < 0.01 among antimicrobial resistant and susceptible strains was also observed notwithstanding an overall greater occurrence of virulence factors among the latter. Conclusions: This study provides a snapshot of UPEC complexity in Jamaica and highlights the significant clonal heterogeneity among strains. Such outcomes emphasise the need for evidence-based strategies in the effective management and control of UTIs.

  9. Antimicrobial resistance in Dschang, Cameroon

    Directory of Open Access Journals (Sweden)

    Fusi-Ngwa Catherine Kesah

    2013-01-01

    Full Text Available Background: Health-care-associated and community infections remain problematic in most of Africa where the increasing incidences of diseases, wars, poverty, malnutrition, and general environmental deterioration have led to the gradual collapse of the health-care system. Detection of antimicrobial resistance (AMR remains imperative for the surveillance purposes and optimal management of infectious diseases. This study reports the status of AMR in pathogens in Dschang. Materials and Methods: From May 2009 to March 2010, the clinical specimens collected at two hospitals were processed accorded to the standard procedures. Antibiotic testing was performed by E test, and antimycotics by disc-agar diffusion, as recommended by the Clinical and Laboratory Standards Institute on pathogens comprising Staphylococcus aureus (100 strains, Enterococcus faecalis (35, Klebsiella pneumoniae (75, Escherichia coli (50, Proteus mirabilis (30, Pseudomonas aruginosa (50, Acinetobacter species (20, and Candida albicans (150 against common antimicrobials. Results: There was no vancomycin resistance in the cocci, the minimum inhibitory concentration for 90% of these strains MIC 90 was 3 μg/ml, methicillin-resistant S. aureus (MRSA was 43%, benzyl penicillin 89% resistance in S. aureus as opposed to 5.7% in E. faecalis. Low resistance (<10% was recorded to cefoxitin, cefotaxime, and nalidixic acid (MIC 90 3-8 μg/ml against the coliforms, and to ticarcillin, aztreonam, imipenem, gentamicin, and ciprofloxacin among the non-enterobacteria; tetracycline, amoxicillin, piperacillin, and chloramphenicol were generally ineffective. Resistance rates to fluconazole, clotrimazole, econazole, and miconazole were <55% against C. albicans. The pathogens tested exhibited multidrug-resistance. Conclusion: The present findings were intended to support antimicrobial stewardship endeavors and empiric therapy. The past, present, and the future investigations in drug efficacy will continue

  10. Antimicrobial edible films and coatings.

    Science.gov (United States)

    Cagri, Arzu; Ustunol, Zeynep; Ryser, Elliot T

    2004-04-01

    Increasing consumer demand for microbiologically safer foods, greater convenience, smaller packages, and longer product shelf life is forcing the industry to develop new food-processing, cooking, handling, and packaging strategies. Nonfluid ready-to-eat foods are frequently exposed to postprocess surface contamination, leading to a reduction in shelf life. The food industry has at its disposal a wide range of nonedible polypropylene- and polyethylene-based packaging materials and various biodegradable protein- and polysaccharide-based edible films that can potentially serve as packaging materials. Research on the use of edible films as packaging materials continues because of the potential for these films to enhance food quality, food safety, and product shelf life. Besides acting as a barrier against mass diffusion (moisture, gases, and volatiles), edible films can serve as carriers for a wide range of food additives, including flavoring agents, antioxidants, vitamins, and colorants. When antimicrobial agents such as benzoic acid, sorbic acid, propionic acid, lactic acid, nisin, and lysozyme have been incorporated into edible films, such films retarded surface growth of bacteria, yeasts, and molds on a wide range of products, including meats and cheeses. Various antimicrobial edible films have been developed to minimize growth of spoilage and pathogenic microorganisms, including Listeria monocytogenes, which may contaminate the surface of cooked ready-to-eat foods after processing. Here, we review the various types of protein-based (wheat gluten, collagen, corn zein, soy, casein, and whey protein), polysaccharide-based (cellulose, chitosan, alginate, starch, pectin, and dextrin), and lipid-based (waxes, acylglycerols, and fatty acids) edible films and a wide range of antimicrobial agents that have been or could potentially be incorporated into such films during manufacture to enhance the safety and shelf life of ready-to-eat foods.

  11. Antimicrobial and biofilm inhibiting diketopiperazines.

    Science.gov (United States)

    de Carvalho, M P; Abraham, W-R

    2012-01-01

    Diketopiperazines are the smallest cyclic peptides known. 90% of Gram-negative bacteria produce diketopiperazines and they have also been isolated from Gram-positive bacteria, fungi and higher organisms. Biosynthesis of cyclodipeptides can be achieved by dedicated nonribosomal peptide synthetases or by a novel type of synthetases named cyclopeptide synthases. Since the first report in 1924 a large number of bioactive diketopiperazines was discovered spanning activities as antitumor, antiviral, antifungal, antibacterial, antiprion, antihyperglycemic or glycosidase inhibitor agents. As infections are of increasing concern for human health and resistances against existing antibiotics are growing this review focuses on the antimicrobial activities of diketopiperazines. The antibiotic bicyclomycin is a diketopiperazine and structure activity studies revealed the unique nature of this compound which was finally developed for clinical applications. The antimicrobial activities of a number of other diketopiperazines along with structure activity relationships are discussed. Here a special focus is on the activity-toxicity problem of many compounds setting tight limitations to their application as drugs. Not only these classical antimicrobial activities but also proposed action in modulating bacterial communication as a new target to control biofilms will be evaluated. Pathogens organized in biofilms are difficult to eradicate because of the increase of their tolerance for antibiotics for several orders. Diketopiperazines were reported to modulate LuxR-mediated quorum-sensing systems of bacteria, and they are considered to influence cell-cell signaling offering alternative ways of biofilm control by interfering with microbial communication. Concluding the review we will finally discuss the potential of diketopiperazines in the clinic to erase biofilm infections.

  12. Control of the development and prevalence of antimicrobial resistance in bacteria of food animal origin in Japan: a new approach for risk management of antimicrobial veterinary medicinal products in Japan.

    Science.gov (United States)

    Asai, Tetsuo; Hiki, Mototaka; Ozawa, Manao; Koike, Ryoji; Eguchi, Kaoru; Kawanishi, Michiko; Kojima, Akemi; Endoh, Yuuko S; Hamamoto, Shuichi; Sakai, Masato; Sekiya, Tatsuro

    2014-03-01

    Antimicrobial agents are essential for controlling bacterial disease in food-producing animals and contribute to the stable production of safe animal products. The use of antimicrobial agents in these animals affects the emergence and prevalence of antimicrobial resistance in bacteria isolated from animals and animal products. As disease-causing bacteria are often transferred from food-producing animals to humans, the food chain is considered a route of transmission for the resistant bacteria and/or resistance genes. The Food Safety Commission of Japan (FSC) has been assessing the risk posed to human health by the transmission of antimicrobial-resistant bacteria from livestock products via the food chain. In addition to the FSC's risk assessments, the Japanese Ministry of Agriculture, Forestry and Fisheries has developed risk-management guidelines to determine feasible risk-management options for the use of antimicrobial veterinary medicinal products during farming practices. This report includes information on risk assessment and novel approaches for risk management of antimicrobial veterinary medicinal products for mitigating the risk of development and prevalence of antimicrobial resistance in bacteria originating from food-producing animals in Japan.

  13. [Antimicrobial activity of Calendula L. plants].

    Science.gov (United States)

    Radioza, S A; Iurchak, L D

    2007-01-01

    The sap of different organs of genus Calendula plant species has been studied for antimicrobial activity. The sap of racemes demonstrated the most expressed antimicrobial effect while that of the roots - the least one. Calendula species inhibited all tested pathogenic microorganisms, especially Pseudomonas syringae, P. fluorescens, Xanthomonas campestris, Agrobacterium tumefaciens. Calendula suffruticosa was the most active to all investigated microorganisms.

  14. Synthesis and antimicrobial activity of squalamine analogue.

    Science.gov (United States)

    Kim, H S; Choi, B S; Kwon, K C; Lee, S O; Kwak, H J; Lee, C H

    2000-08-01

    Synthesis and antimicrobial activity of squalamine analogue 2 are reported. The synthesis of 2 was accomplished from bisnoralcohol 3. The spermidine moiety was introduced via reductive amination of an appropriately functionalized 3beta-aminosterol with spermidinyl aldehyde 17 utilizing sodium triacetoxyborohydride as the reducing agent. Compound 2 shows weaker antimicrobial activity than squalamine.

  15. Antimicrobial peptides in innate immune responses

    DEFF Research Database (Denmark)

    Sorensen, O.E.; Borregaard, N.; Cole, A.M.

    2008-01-01

    Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de ...

  16. Cationic Antimicrobial Polymers and Their Assemblies

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2013-05-01

    Full Text Available Cationic compounds are promising candidates for development of antimicrobial agents. Positive charges attached to surfaces, particles, polymers, peptides or bilayers have been used as antimicrobial agents by themselves or in sophisticated formulations. The main positively charged moieties in these natural or synthetic structures are quaternary ammonium groups, resulting in quaternary ammonium compounds (QACs. The advantage of amphiphilic cationic polymers when compared to small amphiphilic molecules is their enhanced microbicidal activity. Besides, many of these polymeric structures also show low toxicity to human cells; a major requirement for biomedical applications. Determination of the specific elements in polymers, which affect their antimicrobial activity, has been previously difficult due to broad molecular weight distributions and random sequences characteristic of radical polymerization. With the advances in polymerization control, selection of well defined polymers and structures are allowing greater insight into their structure-antimicrobial activity relationship. On the other hand, antimicrobial polymers grafted or self-assembled to inert or non inert vehicles can yield hybrid antimicrobial nanostructures or films, which can act as antimicrobials by themselves or deliver bioactive molecules for a variety of applications, such as wound dressing, photodynamic antimicrobial therapy, food packing and preservation and antifouling applications.

  17. Antimicrobial Activities of Dorema Auchri

    Directory of Open Access Journals (Sweden)

    A Sharifi

    2011-01-01

    Full Text Available Introduction & Objective: Due to emerging of resistance of microorganisms to antibiotics, investigations for novel antimicrobial agents have always been one of the major preoccupations of the medical society. Traditional medicine systems have played an important role during human evolution and development. Today, a number of medical herbs around the world have been studied for their medicinal activities. Amongst the several herbal medicine used as a medicine, Dorema auchri is yet another potent herbal medicine which has not been extensively studied for the medicinal uses in comparison with other herbal medicine. Dorema auchri has a long history of use as a sore and food additive in Yasuj, Iran. However, not much scientific work has been conducted on Dorema auchri antimicrobial activities. The present study aimed to study the antimicrobial properties of Dorema auchri on some pathogen microorganisms. Materials & Methods: In the present study was conducted at Yasuj University of Medical Sciences in 2009. After collection and preparation of hydro alcoholic extract of Dorena auchri, the extract was used to study its activities against human pathogen microorganisms (overall 10 microorganisms. The determination of minimal inhibitory concentration (MIC and minimum lethal concentration were evaluated for this extract. The antimicrobial potent of Dorema auchri extract was compared with commercial antibiotics. Each experiment was done three times and collected data were analyzed by SPSS using ANOVA and Chi-Square tests. Results: Findings of this study showed that in 10 mg/ml concentration, all bacteria were resistant to Dorema auchri extract. In 20 mg/ml concentration, only Staphylococcus areus and Staphylococcus epidermis showed zone of inhibition (ZOI 10 mm and 13 mm respectively. In 40 mg/ml concentration, the maximum ZOI was 15 mm in Staphylococcus areus and 80 mg/ml concentration, the maximum ZOI was 20 mm in Staphylococcus areus. The acceptable MIC

  18. Antimicrobial evaluation of mangiferin analogues

    Directory of Open Access Journals (Sweden)

    Singh S

    2009-01-01

    Full Text Available The naturally occurring xanthone glycoside mangiferin has been isolated by column chromatography from the ethanol extract of stem bark of Mangifera indica. Mangiferin was further converted to 5-(N-phenylaminomethylenomangiferin, 5-(N-p-chlorophenylaminomethyleno mangiferin, 5-(N-2-methylphenylaminomethyleno mangiferin, 5-(N-p-methoxyphenylaminomethyleno mangiferin, 5-(N,N-diphenylaminomethyleno mangiferin, 5-(N--napthylaminomethyleno mangiferin and 5-(N-4-methylphenylaminomethyleno mangiferin. Mangiferin and its analogues were characterized by melting point and R f value determination and through spectral technique like UV, IR, and NMR spectral analysis. The synthesized compounds were screened for antimicrobial activity.

  19. Antimicrobial Evaluation of Mangiferin Analogues

    Science.gov (United States)

    Singh, S. K.; Kumar, Y.; Kumar, S. Sadish; Sharma, V. K.; Dua, K.; Samad, A.

    2009-01-01

    The naturally occurring xanthone glycoside mangiferin has been isolated by column chromatography from the ethanol extract of stem bark of Mangifera indica. Mangiferin was further converted to 5-(N-phenylaminomethyleno)mangiferin, 5-(N-p-chlorophenylaminomethyleno) mangiferin, 5-(N-2-methylphenylaminomethyleno) mangiferin, 5-(N-p-methoxyphenylaminomethyleno) mangiferin, 5-(N, N-diphenylaminomethyleno) mangiferin, 5-(N--napthylaminomethyleno) mangiferin and 5-(N-4-methylphenylaminomethyleno) mangiferin. Mangiferin and its analogues were characterized by melting point and Rf value determination and through spectral technique like UV, IR, and NMR spectral analysis. The synthesized compounds were screened for antimicrobial activity. PMID:20490307

  20. [Antimicrobial sensitive of Morganella morganii].

    Science.gov (United States)

    Zalas-Wiecek, Patrycja; Michalska, Anna; Sielska, Barbara; Gospodarek, Eugenia

    2011-01-01

    The aim of this study was the evaluation of the antimicrobial sensitive of Morganella morganii rods isolated from clinical samples. This study included 50 of M. morganii strains isolated in the Clinical Microbiology Department of dr. A. Jurasz University Hospital in 2008-2009. All of strains were sensitive to carbapenems (imipenem, meropenem, ertapenem, doripenem) and piperacillin/tazobactam and most of them to beta-lactam antibiotics, aminoglycosides and fluorochinolons. Resistance to tetracyclines demonstrated 38,0% strains and to doxycycline - 40,0%. One out of 6 strains isolated from urine samples were sensitive to nitrofurantoin. Extended Spectrum Beta-Lactamases were produced by 5 (10,0%) strains.

  1. Evaluation of the profile of antimicrobial resistance and the presence of the genes mecA and qacA/B in staphylococcus spp. isolated from minas frescal type cheese

    OpenAIRE

    Costa, Juliana de Castro Beltrão

    2010-01-01

    Diversos relatos indicam que queijos Minas Frescal comercializados no Brasil são amplamente contaminados, sendo o gênero Staphylococcus spp. incriminado em diversos surtos de toxinfecção alimentar. Os objetivos deste estudo são a pesquisa de características fenotípicas e genotípicas de resistência a antimicrobianos de Staphylococcus spp. isolados a partir de queijo Minas Frescal, verificando a presença dos genes mecA e qacA/B através da técnica de reação em cadeia da polimerase (PCR). Es...

  2. Antimicrobial resistance and virulence factors in Escherichia coli from swedish dairy calves

    Directory of Open Access Journals (Sweden)

    de Verdier Kerstin

    2012-01-01

    Full Text Available Abstract Background In Sweden, knowledge about the role of enteropathogenic Escherichia coli in neonatal calf diarrhea and the occurrence of antimicrobial resistance in E. coli from young calves is largely unknown. This has therapeutic concern and such knowledge is also required for prudent use of antimicrobials. Methods In a case control study Esherichia coli isolated from faecal samples from dairy calves were phenotyped by biochemical fingerprinting and analyzed for virulence genes by PCR. Antimicrobial susceptibility was tested by determination of minimum inhibitory concentration (MIC. Farm management data were collected and Fisher's exact test and univariable and multivariable logistic regression analysis were performed. Results Of 95 E. coli tested for antimicrobial susceptibility 61% were resistant to one or more substances and 28% were multi-resistant. The virulence gene F5 (K99 was not found in any isolate. In total, 21 out of 40 of the investigated virulence genes were not detected or rarely detected. The virulence genes espP, irp, and fyuA were more common in resistant E. coli than in fully susceptible isolates (P terZ was associated with calf diarrhea (P ≤ 0.01. The participating 85 herds had a median herd size of 80 lactating cows. Herds with calf diarrhea problems were larger (> 55 cows; P P There was no association between calf diarrhea and diversity of enteric E. coli. Conclusions Antimicrobial resistance was common in E. coli from pre-weaned dairy calves, occurring particularly in calves from herds experiencing calf diarrhea problems. The results indicate that more factors than use of antimicrobials influence the epidemiology of resistant E. coli. Enteropathogenic E. coli seems to be an uncommon cause of neonatal calf diarrhea in Swedish dairy herds. In practice, calf diarrhea should be regarded holistically in a context of infectious agents, calf immunity, management practices etc. We therefore advice against routine

  3. Antimicrobial resistance of Staphylococcus spp. from small ruminant mastitis in Brazil

    OpenAIRE

    Chirles A. de França; Peixoto,Rodolfo de M.; Cavalcante,Marielly B.; Melo, Natoniel F. de; Oliveira,Celso José B.; Josir Laine A. Veschi; Mota,Rinaldo A.; Mateus M. Costa

    2012-01-01

    The study aimed to determine the antimicrobial resistance patterns and to identify molecular resistance markers in Staphylococcus spp. (n=210) isolated from small ruminant mastitis in Brazil. The antimicrobial resistance patterns were evaluated by the disk diffusion test and by detection of the presence of mecA, blaZ, ermA, ermB, ermC and msrA genes by PCR. The efflux pump test was performed using ethidium bromide and biofilm production was determined by Congo red agar test along with PCR for...

  4. Genome-Wide Identification of Antimicrobial Intrinsic Resistance Determinants in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Vestergaard, Martin; Leng, Bingfeng; Haaber, Jakob

    2016-01-01

    The emergence of antimicrobial resistance severely threatens our ability to treat bacterial infections. While acquired resistance has received considerable attention, relatively little is known of intrinsic resistance that allows bacteria to naturally withstand antimicrobials. Gene products......, atpA, atpB, atpG and atpH, reduced the minimum inhibitory concentration (MIC) of gentamicin 16-fold. To elucidate the potential of the screen, we examined treatment efficacy in the Galleria mellonella infection model. Gentamicin efficacy was significantly improved, when treating larvae infected...

  5. Application of natural antimicrobials for food preservation.

    Science.gov (United States)

    Tiwari, Brijesh K; Valdramidis, Vasilis P; O'Donnell, Colm P; Muthukumarappan, Kasiviswanathan; Bourke, Paula; Cullen, P J

    2009-07-22

    In this review, antimicrobials from a range of plant, animal, and microbial sources are reviewed along with their potential applications in food systems. Chemical and biochemical antimicrobial compounds derived from these natural sources and their activity against a range of pathogenic and spoilage microorganisms pertinent to food, together with their effects on food organoleptic properties, are outlined. Factors influencing the antimicrobial activity of such agents are discussed including extraction methods, molecular weight, and agent origin. These issues are considered in conjunction with the latest developments in the quantification of the minimum inhibitory (and noninhibitory) concentration of antimicrobials and/or their components. Natural antimicrobials can be used alone or in combination with other novel preservation technologies to facilitate the replacement of traditional approaches. Research priorities and future trends focusing on the impact of product formulation, intrinsic product parameters, and extrinsic storage parameters on the design of efficient food preservation systems are also presented.

  6. Antimicrobial Peptides: Multifunctional Drugs for Different Applications

    Directory of Open Access Journals (Sweden)

    Lea-Jessica Albrecht

    2012-02-01

    Full Text Available Antimicrobial peptides (APs are an important part of the innate immune system in epithelial and non-epithelial surfaces. So far, many different antimicrobial peptides from various families have been discovered in non-vertebrates and vertebrates. They are characterized by antibiotic, antifungal and antiviral activities against a variety of microorganisms. In addition to their role as endogenous antimicrobials, APs participate in multiple aspects of immunity. They are involved in septic and non-septic inflammation, wound repair, angiogenesis, regulation of the adaptive immune system and in maintaining homeostasis. Due to those characteristics AP could play an important role in many practical applications. Limited therapeutic efficiency of current antimicrobial agents and the emerging resistance of pathogens require alternate antimicrobial drugs. The purpose of this review is to highlight recent literature on functions and mechanisms of APs. It also shows their current practical applications as peptide therapeutics and bioactive polymers and discusses the possibilities of future clinical developments.

  7. Methods of Antimicrobial Coating of Diverse Materials

    Science.gov (United States)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of coating diverse substrate materials with antimicrobial agents have been developed. Originally intended to reduce health risks to astronauts posed by pathogenic microorganisms that can grow on surfaces in spacecraft, these methods could also be used on Earth for example, to ensure sterility of surgical inserts and other medical equipment. The methods involve, generally, chemical preparation of substrate surfaces to enable attachment of antimicrobial molecules to the substrate surfaces via covalent bonds. Substrate materials that have been treated successfully include aluminum, glass, a corrosion-resistant nickel alloy, stainless steel, titanium, and poly(tetrafluoroethylene). Antimicrobial agents that have been successfully immobilized include antibiotics, enzymes, bacteriocins, bactericides, and fungicides. A variety of linkage chem istries were employed. Activity of antimicrobial coatings against gram-positive bacteria, gram-negative bacteria, and fungi was demonstrated. Results of investigations indicate that the most suitable combination of antimicrobial agent, substrate, and coating method depends upon the intended application.

  8. Antimicrobial resistant bacteria in the food chain

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar

    2003-01-01

    Antimicrobials are used for treatment and prevention of disease in food animals and as feed additives for growth promotion. All uses lead to the development of resistant bacteria, some of which are pathogenic to humans. Current main concerns are with resistance in Salmonella and Campylobacter...... to fluoroquinolones, which are used for empirical treatment of diarrhea in humans. Resistance to vancomycin and Synercid((R)) in enterococci is associated with use of similar drugs as growth promoters in food animals. Danish food animal producers have terminated the use of antimicrobial growth promoters. This has...... reduced the total use of antimicrobials by more than 50% and markedly reduced levels of resistance. There is an urgent need to implement globally, WHO principles for prudent use of antimicrobials in food animals. Use of antimicrobials as growth promoters could and should be terminated completely....

  9. Antimicrobial peptides important in innate immunity.

    Science.gov (United States)

    Cederlund, Andreas; Gudmundsson, Gudmundur H; Agerberth, Birgitta

    2011-10-01

    Antimicrobial peptides are present in all walks of life, from plants to animals, and they are considered to be endogenous antibiotics. In general, antimicrobial peptides are determinants of the composition of the microbiota and they function to fend off microbes and prevent infections. Antimicrobial peptides eliminate micro-organisms through disruption of their cell membranes. Their importance in human immunity, and in health as well as disease, has only recently been appreciated. The present review provides an introduction to the field of antimicrobial peptides in general and discusses two of the major classes of mammalian antimicrobial peptides: the defensins and the cathelicidins. The review focuses on their structures, their main modes of action and their regulation.

  10. Extracellular DNA-induced antimicrobial peptide resistance mechanisms in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Shawn eLewenza

    2013-02-01

    Full Text Available Extracellular DNA (eDNA is in the environment, bodily fluids, in the matrix of biofilms, and accumulates at infection sites. Extracellular DNA can function as a nutrient source, a universal biofilm matrix component and an innate immune effector in extracellular DNA traps. In biofilms, eDNA is required for attachment, aggregation and stabilization of microcolonies. We have recently shown that eDNA can sequester divalent metal cations, which has interesting implications on antibiotic resistance. Extracellular DNA binds metal cations and thus activates the Mg2+-responsive PhoPQ and PmrAB two-component systems. In Pseudomonas aeruginosa and many other Gram-negative bacteria, the PhoPQ/PmrAB systems control various genes required for virulence and resisting killing by antimicrobial peptides, including the pmr genes (PA3552-PA3559 that are responsible for the addition of aminoarabinose to lipid A. The PA4773-PA4775 genes are a second DNA-induced cluster and are required for the production of spermidine on the outer surface, which protects the outer membrane from antimicrobial peptide treatment. Both modifications mask the negative surface charges and limit membrane damage by antimicrobial peptides. DNA-enriched biofilms or planktonic cultures have increased antibiotic resistance phenotypes to antimicrobial peptides and aminoglycosides. These dual antibiotic resistance and immune evasion strategies may be expressed in DNA-rich environments and contribute to long-term survival.

  11. Antimicrobial resistance and its association with tolerance to heavy metals in agriculture production.

    Science.gov (United States)

    Yu, Zhongyi; Gunn, Lynda; Wall, Patrick; Fanning, Séamus

    2017-06-01

    Antimicrobial resistance is a recognized public health challenge that since its emergence limits the therapeutic options available to veterinarians and clinicians alike, when treatment is warranted. This development is further compounded by the paucity of new antibiotics. The agri-food industry benefits from the availability of antimicrobial compounds for food-animal production and crop protection. Nonetheless, their improper use can result in the selection for bacteria that are phenotypically resistant to these compounds. Another class of agents used in agriculture includes various cationic metals that can be included in animal diets as nutritional supplements or spread on pastures to support crop growth and protection. Heavy metals, in particular, are giving rise to concerns among public health professionals, as they can persist in the environment remaining stable for prolonged periods. Moreover, bacteria can also exhibit resistance to these chemical elements and the genes encoding this phenotype can be physically localized to plasmids that may also contain one or more antimicrobial resistance-encoding gene(s). This paper reviews our current understanding of the role that bacteria play in expressing resistance to heavy metals. It will describe how heavy metals are used in agri-food production, and explore evidence available to link resistance to heavy metals and antimicrobial compounds. In addition, possible solutions to reduce the impact of heavy metal resistance are also discussed, including using organic minerals and reducing the level of trace minerals in animal feed rations.

  12. Antimicrobial resistance: cost and containment.

    Science.gov (United States)

    Coast, Joanna; Smith, Richard D

    2003-08-01

    There is growing evidence that antimicrobial resistance causes serious consequences for individuals as well as leading to increased healthcare costs. The containment of resistance is therefore a policy problem which will impact on all health systems in the next few years. Unfortunately, there is, as yet, no definitive evidence suggesting that particular control measures are successful in containing either the emergence or transmission of antimicrobial resistance. Furthermore, few studies contain information about costs and even where there is such information it is generally inadequate because of the narrow perspectives from which analyses are conducted. In part, this is due to methodological problems associated with the inclusion of cost data: measuring and valuing what are often intangible costs; identifying costs associated with organizational change; and accounting for interaction between costs at levels from the individual to the international. Good quality research, including both economic evaluation and comprehensive economic modelling, is required to determine the most cost-effective combination of strategies to pursue in combating resistance, and to find ways around these methodological difficulties.

  13. Antimicrobial peptide action on parasites.

    Science.gov (United States)

    Torrent, Marc; Pulido, David; Rivas, Luis; Andreu, David

    2012-08-01

    Diseases caused by protozoan parasites can pose a severe thread to human health and are behind some serious neglected tropical diseases like malaria and leishmaniasis. Though several different drugs have been developed in order to eradicate these diseases, a successful candidate has not yet been discovered. Among the most active compounds tested, antimicrobial peptides (AMPs) are particularly appealing because of their wide spectrum of action. AMPs have been described to perturb protozoan homeostasis by disrupting the cellular membranes but also by interfering with key processes in the parasite metabolism. In this review we describe the diverse mechanisms of action of AMPs on protozoan targets and how they can be exploited to treat diseases. Moreover, we describe with detail the antimicrobial action of AMPs on two major parasitical infections: leishmaniasis and malaria. All the features reviewed here show that AMPs are promising drugs to target protozoan parasites and that further understanding of the mechanism of action of these compounds will lead to improved drugs that could be worth to test in a clinical phase.

  14. Antimicrobial outcomes in plasma medicine

    Science.gov (United States)

    Ryan, Thomas P.; Stalder, Kenneth R.; Woloszko, Jean

    2015-03-01

    Plasma is referred to as the fourth state of matter and is frequently generated in the environment of a strong electric field. The result consists of highly reactive species--ions, electrons, reactive atoms and molecules, and UV radiation. Plasma Medicine unites a number of fields, including Physics, Plasma Chemistry, Cell Biology, Biochemistry, and Medicine. The treatment modality utilizes Cold Atmospheric Plasma (CAP), which is able to sterilize and treat microbes in a nonthermal manner. These gas-based plasma systems operate at close to room temperature and atmospheric pressure, making them very practical for a range of potential treatments and are highly portable for clinical use throughout the health care system. The hypothesis is that gas based plasma kills bacteria, fungus, and viruses but spares mammalian cells. This paper will review systematic work which shows examples of systems and performance in regards to antimicrobial effects and the sparing of mammalian cells. The mechanism of action will be discussed, as well as dosing for the treatment of microbial targets, including sterilization processes, another important healthcare need. In addition, commercial systems will be overviewed and compared, along with evidence-based, patient results. The range of treatments cover wound treatment and biofilms, as well as antimicrobial treatment, with little chance for resistance and tolerance, as in drug regimens. Current clinical studies include applications in dentistry, food treatment, cancer treatment, wound treatment for bacteria and biofilms, and systems to combat health care related infections.

  15. The safety of antimicrobial drugs

    Directory of Open Access Journals (Sweden)

    Ćupić Vitomir

    2016-01-01

    Full Text Available The discovery and introduction of antimicrobial drugs in clinical practice has been recorded as one of the greatest achievements in the history of medicine. The application of these drugs, made a big, almost revolutionary upheaval in treatment of many infectious diseases. Its significance for the humanity lies in the fact that hundreds of thousands of people, until then condemned to a certain death, has been saved now. However, it was shown that antimicrobial therapy carries some risk of possible occurrence of undesirable and toxic effects, such as direct toxic effects, development of resistance, the impact on the normal microflora or disorder of micropopulation metabolic functions in digestive tract of ruminants, unwanted interactions with other drugs, damage or necrosis of the tissue at the injection site, residues in foodstuff intended for human consumption, suppression of immune system or defense mechanisms of the body, and damage of fetal or neonatal tissue. All mentioned, directly or indirectly, to a greater or lesser degree can reduce the safety of these drugs.

  16. Antimicrobial peptides in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    A Bogaerts

    2010-01-01

    Full Text Available The nematode Caenorhabditis elegans is one of the most successful model species for experimental research because of its sequenced genome, the versatile genetic toolkit and the straightforward breeding among others. In natural conditions however, this tiny worm is constantly surrounded by micro-organisms, simultaneously a source of indispensable nutrition and inevitable pathogens. Lacking an adaptive immune system, the worm solely relies on its innate immune defence to cope with its challenging life style. Hence C. elegans is an excellent model to gain more insight in innate immunity, which is remarkably preserved between invertebrate and vertebrate animals. The innate defence consists of receptors to detect potential pathogens, a complex network of signalling pathways and last but not least, effector molecules to abolish harmful microbes. In this review, we focus on the antimicrobial peptides, a vital subgroup of effector molecules. We summarise the current knowledge of the different families of C. elegans antimicrobial peptides, comprising NLPs, caenacins, ABFs, caenopores, and a recently discovered group with antifungal activity among which thaumatin-like proteins.

  17. Azorean wild rabbits as reservoirs of antimicrobial resistant Escherichia coli.

    Science.gov (United States)

    Marinho, Catarina; Igrejas, Gilberto; Gonçalves, Alexandre; Silva, Nuno; Santos, Tiago; Monteiro, Ricardo; Gonçalves, David; Rodrigues, Tiago; Poeta, Patrícia

    2014-12-01

    Antibiotic resistance in bacteria is an increasing problem that is not only constrained to the clinical setting but also to other environments that can lodge antibiotic resistant bacteria and therefore they may serve as reservoirs of genetic determinants of antibiotic resistance. One hundred and thirty-six faecal samples from European wild rabbits (Oryctolagus cuniculus algirus) were collected on São Jorge Island in Azores Archipelago, and analysed for Escherichia coli isolates. Seventy-seven isolates (56.6%) were recovered and studied for antimicrobial resistance, one isolate per positive sample. Thirteen (16.9%), 19 (24.7%), 25 (32.4%) and 20 (26%) isolates were ascribed to A, B1, B2 and D phylogenetic groups, respectively, by specific primer polymerase chain reaction. Different E. coli isolates were found to be resistant to ampicillin (16.9%), tetracycline (1.3%), streptomycin (42.9%), sulfamethoxazole-trimethoprim (1.3%), amikacin (1.3%), tobramycin (2.6%) and nalidixic acid (1.3%). Additionally, the blaTEM, tetA, strA/strB, aadA, sul1, intI, intI2 and qacEΔ+sul1 genes were found in most resistant isolates. This study showed that E. coli from the intestinal tract of wild rabbits from Azores Archipelago are resistant to widely prescribed antibiotics in medicine and they constitute a reservoir of antimicrobial resistant genes, which may play a significant role in the spread of antimicrobial resistance. Therefore, antibiotic resistant E. coli from Azorean wild rabbits may represent an ecological and public health problem.

  18. Genotyping using whole-genome sequencing is a realistic alternative to surveillance based on phenotypic antimicrobial susceptibility testing

    DEFF Research Database (Denmark)

    Zankari, Ea; Hasman, Henrik; Kaas, Rolf Sommer;

    2013-01-01

    genes and MLST types (where MLST stands for multilocus sequence typing). ResFinder results were compared with phenotypic antimicrobial susceptibility testing results using EUCAST epidemiological cut-off values and MLST types. Results: A total of 3051 different phenotypic tests were performed; 482 led......-genome sequencing (WGS) may soon be within reach even for routine surveillance and clinical diagnostics. The aim of this study was to evaluate WGS as a routine tool for surveillance of antimicrobial resistance compared with current phenotypic procedures. Methods: Antimicrobial susceptibility tests were performed...... on 200 isolates originating from Danish pigs, covering four bacterial species. Genomic DNA was purified from all isolates and sequenced as paired-end reads on the Illumina platform. The web servers ResFinder and MLST (www.genomicepidemiology.org) were used to identify acquired antimicrobial resistance...

  19. Peptidomics and genomics analysis of novel antimicrobial peptides from the frog, Rana nigrovittata.

    Science.gov (United States)

    Ma, Yufang; Liu, Cunbao; Liu, Xiuhong; Wu, Jing; Yang, Hailong; Wang, Yipeng; Li, Jianxu; Yu, Haining; Lai, Ren

    2010-01-01

    Much attention has been paid on amphibian peptides for their wide-ranging pharmacological properties, clinical potential, and gene-encoded origin. More than 300 antimicrobial peptides (AMPs) from amphibians have been studied. Peptidomics and genomics analysis combined with functional test including microorganism killing, histamine-releasing, and mast cell degranulation was used to investigate antimicrobial peptide diversity. Thirty-four novel AMPs from skin secretions of Rana nigrovittata were identified in current work, and they belong to 9 families, including 6 novel families. Other three families are classified into rugosin, gaegurin, and temporin family of amphibian AMP, respectively. These AMPs share highly conserved preproregions including signal peptides and spacer acidic peptides, while greatly diversified on mature peptides structures. In this work, peptidomics combined with genomics analysis was confirmed to be an effective way to identify amphibian AMPs, especially novel families. Some AMPs reported here will provide leading molecules for designing novel antimicrobial agents.

  20. Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria

    Directory of Open Access Journals (Sweden)

    Palloma Rodrigues Marinho

    2009-08-01

    Full Text Available Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3 isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

  1. Flagellin stimulates protective lung mucosal immunity: role of cathelicidin-related antimicrobial peptide.

    Science.gov (United States)

    Yu, Fu-shin; Cornicelli, Matthew D; Kovach, Melissa A; Newstead, Michael W; Zeng, Xianying; Kumar, Ashok; Gao, Nan; Yoon, Sang Gi; Gallo, Richard L; Standiford, Theodore J

    2010-07-15

    TLRs are required for generation of protective lung mucosal immune responses against microbial pathogens. In this study, we evaluated the effect of the TLR5 ligand flagellin on stimulation of antibacterial mucosal immunity in a lethal murine Pseudomonas aeruginosa pneumonia model. The intranasal pretreatment of mice with purified P. aeruginosa flagellin induced strong protection against intratracheal P. aeruginosa-induced lethality, which was attributable to markedly improved bacterial clearance, reduced dissemination, and decreased alveolar permeability. The protective effects of flagellin on survival required TLR5 and were observed even in the absence of neutrophils. Flagellin induced strong induction of innate genes, most notably the antimicrobial peptide cathelicidin-related antimicrobial peptide. Finally, flagellin-induced protection was partially abrogated in cathelicidin-related antimicrobial peptide-deficient mice. Our findings illustrate the profound stimulatory effect of flagellin on lung mucosal innate immunity, a response that might be exploited therapeutically to prevent the development of gram-negative bacterial infection of the respiratory tract.

  2. [In vitro study of antimicrobial activity of lactoferrins from various sources].

    Science.gov (United States)

    Grammatikova, N E; Rezvan, S P; Nemtsova, E R; Bezborodova, O A; Tutykhina, I L; Naroditskiĭ, B S; Iakubovskaia, R I

    2010-01-01

    Comparative antimicrobial activity of lactoferrins from various sources (native lactoferrin from Laprot, human hololactoferrin, recombinant human lactoferrin isolated from the cultural medium of permissive cell culture transfected using pseudoadenovirus nanostructure with the human lactoferrin gene, and native bovine lactoferrin) was studied to prove the possibility of their use for development of antimicrobial drugs. It was shown that all the substances were active against the Bacillus standard strains. The antibacterial activity was almost independent of the degree of saturation the lactoferrin molecules with Fe3+. The native human lactoferrin was more active than hololactoferrin against Candida when evaluated by the minimum inhibitory concentration (MIC). Fe(3+)-Non aturated recombinant human lactoferrin demonstrated the antimicrobial activity (by MIC) similar to that of the native human lactoferrin. The results showed that native and recombinant human lactoferrins might be used for the development of intravenous and intracavitary dosage forms, while the native bovine lactoferrin could be useful in development of oral drugs.

  3. Heat stable antimicrobial activity of Burkholderia gladioli OR1 against clinical drug resistant isolates

    Science.gov (United States)

    Bharti, Pratibha; Anand, Vivek; Chander, Jagdish; Singh, Inder Pal; Singh, Tej Vir; Tewari, Rupinder

    2012-01-01

    Background & objectives: Drug resistant microbes are a serious challenge to human health. During the search for novel antibiotics/inhibitors from the agricultural soil, a bacterial colony was found to inhibit the growth of clinical isolates including Staphylococcus (resistant to amikacin, ciprofloxacin, clindamycin, clinafloxacin, erythromycin, gentamicin and methicillin) and Candida (resistant to fluconazole and itraconazole). The culture was identified as Burkholderia gladioli and produced at least five different antimicrobial compounds which were highly stable at high temperature (121°C) and in the broad pH range (3.0-11.0). We report here the antimicrobial activity of B. gladioli against drug resistant bacterial pathogens. Methods: The bacterial culture was identified using morphological, biochemical and 16S rRNA gene sequencing techniques. The antimicrobial activity of the identified organism against a range of microbial pathogens was checked by Kirby-Bauer's disc diffusion method. The antimicrobial compounds in the cell free supernatant were chloroform-extracted and separated by thin layer chromatography (TLC). Results: B. gladioli OR1 exhibited broad spectrum antimicrobial activity against drug resistant clinical isolates belonging to various genera of bacteria (Staphylococcus, Enterobacter, Enterococcus, Acinetobacter and Citrobacter) and a fungus (Candida). Based on TLC profile and bioautography studies, the chloroform extract of B. gladioli OR1 consisted of at least three anti-staphylococcal and two anti-Candida metabolites. The antimicrobial activity was heat stable (121°C/20 min) as well as pH stable (3.0-11.0). Interpretation & conclusions: The bacterial soil isolate, B. gladioli OR1 possessed the ability to kill various drug resistant bacteria and a fungus. This organism produced many antimicrobial metabolites which might have the potential to be used as antibiotics in future. PMID:22771597

  4. Antimicrobial use in long-term-care facilities

    NARCIS (Netherlands)

    Nicolle, LE; Bentley, DW; Garibaldi, R; Neuhaus, EG; Smith, PW

    2000-01-01

    There is intense antimicrobial use in long-term-care facilities (LTCFs), and studies repeatedly document that much of this use is inappropriate. The current crisis in antimicrobial resistance, which encompasses the LTCF, heightens concerns of antimicrobial use. Attempts to improve antimicrobial use

  5. 鲍曼不动杆菌生物膜形成能力与生物膜相关基因及耐药性之间的关系%Correlation between the biofilm-forming ability, biofilm-related genes and antimicrobial resistance of Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    韩欣欣; 李庆淑; 申丽婷; 胡丹; 曲彦

    2014-01-01

    Objective To study the biofilm-forming ability and the distribution of biofilm-related genes in Acinetobacter baumannii clinical isolates as well as antimicrobial resistance,to analyze their relationships with the bacterial resistance phenotype.Methods A prospective study was conducted.Biofilm models of 70 strains Acinetobacter baumannii collected in Chengwu County People's Hospital from October 2012 to October 2013 were constructed using 96-well polystyrene plate.In order to analyze the biofilm-forming ability,a qualitative and quantitative analysis was conduct by crystal violet staining assay.And the antimicrobial resistance of different biofilm-forming ability strains was compared including imipenem,amikacin,meropenem,cefepime,sulbactam cefoperazone,trimethoprim,levofloxacin,gentamicin,ciprofloxacin,cefotaxime,ceftizoxime,aztreonam,piperacillin,ceftriaxone,cefuroxime.In addition,the expressions of biofilm-related gene Bap,bfs and intI1 were tested with polymerase chain reaction (PCR) assay.Results Among 70 strains Acinetobacter baumannii,40 strains were multi-drug resistant (57.14%) and 6 strains were pan-drug resistant (8.57%); 68 strains had biofilm-forming ability (97.14%),14 of which were weakly positive,20 were positive and 34 were strongly positive.The antimicrobial resistant rate of Acinetobacter baumannii to imipenem,amikacin,meropenem and cefepime was decreased,it was 30.00%,32.86%,38.57% and 41.43%,respectively.However,the antimicrobial resistant rates to other commonly used antibiotics were all higher than 50%.The drug resistance of Acinetobacter baumannii to levofloxacin (85.71%,45.00%,38.24%,x2=9.225,P=0.010),cefepime (71.43%,45.00%,29.41%,x2=7.222,P=0.027),gentamicin (78.57%,55.00%,38.24%,x2 =6.601,P=0.037) was significantly decreased when biofilm-forming ability reinforced (weakly positive,positive,hadro-positive).Bap gene positive rate of weakly positive,positive and strong positive biofilm-forming strains

  6. A maritime pine antimicrobial peptide involved in ammonium nutrition.

    Science.gov (United States)

    Canales, Javier; Avila, Concepción; Cánovas, Francisco M

    2011-09-01

    A large family of small cysteine-rich antimicrobial peptides (AMPs) is involved in the innate defence of plants against pathogens. Recently, it has been shown that AMPs may also play important roles in plant growth and development. In previous work, we have identified a gene of the AMP β-barrelin family that was differentially regulated in the roots of maritime pine (Pinus pinaster Ait.) in response to changes in ammonium nutrition. Here, we present the molecular characterization of two AMP genes, PpAMP1 and PpAMP2, showing different molecular structure and physicochemical properties. PpAMP1 and PpAMP2 displayed different expression patterns in maritime pine seedlings and adult trees. Furthermore, our expression analyses indicate that PpAMP1 is the major form of AMP in the tree, and its relative abundance is regulated by ammonium availability. In contrast, PpAMP2 is expressed at much lower levels and it is not regulated by ammonium. To gain new insights into the function of PpAMP1, we over-expressed the recombinant protein in Escherichia coli and demonstrated that PpAMP1 strongly inhibited yeast growth, indicating that it exhibits antimicrobial activity. We have also found that PpAMP1 alters ammonium uptake, suggesting that it is involved in the regulation of ammonium ion flux into pine roots.

  7. Proteomics as the final step in the functional metagenomics study of antimicrobial resistance

    Directory of Open Access Journals (Sweden)

    Fiona eFouhy

    2015-03-01

    Full Text Available The majority of clinically applied antimicrobial agents are derived from natural products generated by soil microorganisms and therefore resistance is likely to be ubiquitous in such environments. This is supported by the fact that numerous clinically important resistance mechanisms are encoded within the chromosomes of such bacteria. Advances in genomic sequencing have enabled the in silico identification of putative resistance genes present in these microorganisms. However, it is not sufficient to rely on the identification of putative resistance genes, we must also determine if the resultant proteins confer a resistant phenotype. This will require an analysis pipeline that extends from the extraction of environmental DNA, to the identification and analysis of potential resistance genes and their resultant proteins and phenotypes. This review focuses on the application of functional metagenomics and proteomics to study antimicrobial resistance in diverse environments.

  8. Antimicrobial resistance in India: A review.

    Science.gov (United States)

    Kumar, S Ganesh; Adithan, C; Harish, B N; Sujatha, S; Roy, Gautam; Malini, A

    2013-07-01

    Antimicrobial resistance is an important concern for the public health authorities at global level. However, in developing countries like India, recent hospital and some community based data showed increase in burden of antimicrobial resistance. Research related to antimicrobial use, determinants and development of antimicrobial resistance, regional variation and interventional strategies according to the existing health care situation in each country is a big challenge. This paper discusses the situational analysis of antimicrobial resistance with respect to its problem, determinants and challenges ahead with strategies required in future to reduce the burden in India. Recent data from Google search, Medline and other sources were collected which was reviewed and analyzed by the authors. Hospital based studies showed higher and varied spectrum of resistance in different regions while there are limited number of community based studies at country level. There exists lacunae in the structure and functioning of public health care delivery system with regard to quantification of the problem and various determining factors related to antimicrobial resistance. There is an urgent need to develop and strengthen antimicrobial policy, standard treatment guidelines, national plan for containment of AMR and research related to public health aspects of AMR at community and hospital level in India.

  9. Molecular and antimicrobial susceptibility analyses distinguish clinical from bovine Escherichia coli O157 strains.

    Science.gov (United States)

    Vidovic, Sinisa; Tsoi, Sarah; Medihala, Prabhakara; Liu, Juxin; Wylie, John L; Levett, Paul N; Korber, Darren R

    2013-07-01

    A population-based study combining (i) antimicrobial, (ii) genetic, and (iii) virulence analyses with molecular evolutionary analyses revealed segregative characteristics distinguishing human clinical and bovine Escherichia coli O157 strains from western Canada. Human (n = 50) and bovine (n = 50) strains of E. coli O157 were collected from Saskatchewan and Manitoba in 2006 and were analyzed by using the six-marker lineage-specific polymorphism assay (LSPA6), antimicrobial susceptibility analysis, the colicin assay, plasmid and virulence profiling including the eae, ehxA, espA, iha, stx1, stx2, stx2c, stx2d, stx2d-activatable, stx2e, and stx2f virulence-associated genes, and structure analyses. Multivariate logistic regression and Fisher's exact test strongly suggested that antimicrobial susceptibility was the most distinctive characteristic (P = 0.00487) associated with human strains. Among all genetic, virulence, and antimicrobial determinants, resistance to tetracycline (P coli O157 strains. Among 11 virulence-associated genes, stx2c showed the strongest association with E. coli O157 strains of bovine origin. LSPA6 genotyping showed the dominance of the lineage I genotype among clinical (90%) and bovine (70%) strains, indicating the importance of lineage I in O157 epidemiology and ecology. Population structure analysis revealed that the more-diverse bovine strains came from a unique group of strains characterized by a high degree of antimicrobial resistance and high frequencies of lineage II genotypes and stx2c variants. These findings imply that antimicrobial resistance generated among bovine strains of E. coli O157 has a large impact on the population of this human pathogen.

  10. Antimicrobial susceptibility and genetic characterization of Escherichia coli recovered from frozen game meat.

    Science.gov (United States)

    Mateus-Vargas, Rafael H; Atanassova, Viktoria; Reich, Felix; Klein, Günter

    2017-05-01

    The increasing number of antimicrobial resistant Enterobacteriaceae both in veterinary and human medicine, the dissemination of these bacteria in several environments and their possible repercussions on human health is causing concern. Game meat is usually seen as free of antimicrobial resistant bacteria. The objective of this study was to evaluate the current antimicrobial susceptibility status in generic Escherichia coli isolated from packed frozen game meat from a game handling establishment in Germany. A total of 229 E. coli isolates were obtained from cuts of red deer, roe deer and wild boar. The susceptibility to 12 antimicrobial agents was evaluated by a broth microdilution method according to ISO 20776-1:2006. Minimal Inhibitory Concentration (MIC) values were compared to breakpoints and cut-off values published by the EUCAST. Isolates showing MICs above the reference values were further studied for associated resistance determinants and phylogrouping by PCR. Overall, 16 E. coli isolates (7.0%) showed resistance (microbiological or clinical) to at least one antimicrobial agent tested. Clinical resistance was recorded to ampicillin (5/229) and chloramphenicol (4/229), whereas the MIC of 9 isolates exceeded the epidemiological cut-off value for doxycycline. One of the ampicillin-resistant isolates showed resistance to the β-lactam antibiotic derivatives tested, cephalosporines and aztreonam. Three of 9 non-wild-type isolates for doxycycline were positive for tet (B) genes. The ß-lactam-resistant isolate was found to harbour blaCTX-M-1 gene. These data show a low prevalence of resistant E. coli in packed game meat compared to studies on conventional meat. Although isolates obtained in this study may also be originating from the processing environment and not necessarily from animals, based on our results, it is important to monitor the development of antimicrobial resistance in game animals and products in order to identify future threats for the

  11. Danish Integrated Antimicrobial Resistance Monitoring and Research Program

    Science.gov (United States)

    Heuer, Ole E.; Emborg, Hanne-Dorthe; Bagger-Skjøt, Line; Jensen, Vibeke F.; Rogues, Anne-Marie; Skov, Robert L.; Agersø, Yvonne; Brandt, Christian T.; Seyfarth, Anne Mette; Muller, Arno; Hovgaard, Karin; Ajufo, Justin; Bager, Flemming; Aarestrup, Frank M.; Frimodt-Møller, Niels; Wegener, Henrik C.; Monnet, Dominique L.

    2007-01-01

    Resistance to antimicrobial agents is an emerging problem worldwide. Awareness of the undesirable consequences of its widespread occurrence has led to the initiation of antimicrobial agent resistance monitoring programs in several countries. In 1995, Denmark was the first country to establish a systematic and continuous monitoring program of antimicrobial drug consumption and antimicrobial agent resistance in animals, food, and humans, the Danish Integrated Antimicrobial Resistance Monitoring and Research Program (DANMAP). Monitoring of antimicrobial drug resistance and a range of research activities related to DANMAP have contributed to restrictions or bans of use of several antimicrobial agents in food animals in Denmark and other European Union countries. PMID:18217544

  12. Recent Advances in Antimicrobial Polymers: A Mini-Review

    Directory of Open Access Journals (Sweden)

    Keng-Shiang Huang

    2016-09-01

    Full Text Available Human safety and well-being is threatened by microbes causing numerous infectious diseases resulting in a large number of deaths every year. Despite substantial progress in antimicrobial drugs, many infectious diseases remain difficult to treat. Antimicrobial polymers offer a promising antimicrobial strategy for fighting pathogens and have received considerable attention in both academic and industrial research. This mini-review presents the advances made in antimicrobial polymers since 2013. Antimicrobial mechanisms exhibiting either passive or active action and polymer material types containing bound or leaching antimicrobials are introduced. This article also addresses the applications of these antimicrobial polymers in the medical, food, and textile industries.

  13. Recent Advances in Antimicrobial Polymers: A Mini-Review.

    Science.gov (United States)

    Huang, Keng-Shiang; Yang, Chih-Hui; Huang, Shu-Ling; Chen, Cheng-You; Lu, Yuan-Yi; Lin, Yung-Sheng

    2016-09-20

    Human safety and well-being is threatened by microbes causing numerous infectious diseases resulting in a large number of deaths every year. Despite substantial progress in antimicrobial drugs, many infectious diseases remain difficult to treat. Antimicrobial polymers offer a promising antimicrobial strategy for fighting pathogens and have received considerable attention in both academic and industrial research. This mini-review presents the advances made in antimicrobial polymers since 2013. Antimicrobial mechanisms exhibiting either passive or active action and polymer material types containing bound or leaching antimicrobials are introduced. This article also addresses the applications of these antimicrobial polymers in the medical, food, and textile industries.

  14. Bacteriocins with a broader antimicrobial spectrum prevail in enterococcal symbionts isolated from the hoopoe's uropygial gland.

    Science.gov (United States)

    Ruiz-Rodríguez, Magdalena; Martínez-Bueno, Manuel; Martín-Vivaldi, Manuel; Valdivia, Eva; Soler, Juan J

    2013-09-01

    The use of compounds produced by symbiotic bacteria against pathogens in animals is one of the most exciting discoveries in ecological immunology. The study of those antibiotic metabolites will enable an understanding of the defensive strategies against pathogenic infections. Here, we explore the role of bacteriocins explaining the antimicrobial properties of symbiotic bacteria isolated from the uropygial gland of the hoopoe (Upupa epops). The antagonistic activity of 187 strains was assayed against eight indicator bacteria, and the presence of six bacteriocin genes was detected in the genomic DNA. The presence of bacteriocin genes correlated with the antimicrobial activity of isolates. The most frequently detected bacteriocin genes were those encoding for the MR10 and AS-48 enterocins, which confer the highest inhibition capacity. All the isolates belonged to the genus Enterococcus, with E. faecalis as the most abundant species, with the broadest antimicrobial spectrum and the highest antagonistic activity. The vast majority of E. faecalis strains carried the genes of MR10 and AS-48 in their genome. Therefore, we suggest that fitness-related benefits for hoopoes associated with harbouring the most bactericidal symbionts cause the highest frequency of strains carrying MR10 and AS-48 genes. The study of mechanisms associated with the acquisition and selection of bacterial symbionts by hoopoes is necessary, however, to reach further conclusions.

  15. Species-selective killing of bacteria by antimicrobial peptide-PNAs.

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    Madhav Mondhe

    Full Text Available Broad-spectrum antimicrobials kill indiscriminately, a property that can lead to negative clinical consequences and an increase in the incidence of resistance. Species-specific antimicrobials that could selectively kill pathogenic bacteria without targeting other species in the microbiome could limit these problems. The pathogen genome presents an excellent target for the development of such antimicrobials. In this study we report the design and evaluation of species-selective peptide nucleic acid (PNA antibacterials. Selective growth inhibition of B. subtilis, E. coli, K. pnuemoniae and S. enterica serovar Typhimurium in axenic or mixed culture could be achieved with PNAs that exploit species differences in the translation initiation region of essential genes. An S. Typhimurium-specific PNA targeting ftsZ resulted in elongated cells that were not observed in E. coli, providing phenotypic evidence of the selectivity of PNA-based antimicrobials. Analysis of the genomes of E. coli and S. Typhimurium gave a conservative estimate of >150 PNA targets that could potentially discriminate between these two closely related species. This work provides a basis for the development of a new class of antimicrobial with a tuneable spectrum of activity.

  16. Antimicrobial resistance of Listeria monocytogenes and Listeria innocua from meat products and meat-processing environment.

    Science.gov (United States)

    Gómez, Diego; Azón, Ester; Marco, Noelia; Carramiñana, Juan J; Rota, Carmina; Ariño, Agustín; Yangüela, Javier

    2014-09-01

    A total of 336 Listeria isolates from ready-to-eat (RTE) meat products and meat-processing environments, consisting of 206 Listeria monocytogenes, and 130 Listeria innocua isolates, were characterized by disc diffusion assay and minimum inhibitory concentration (MIC) values for antimicrobial susceptibility against twenty antimicrobials. Resistance to one or two antimicrobials was observed in 71 L. monocytogenes isolates (34.5%), and 56 L. innocua isolates (43.1%). Multidrug resistance was identified in 24 Listeria isolates, 18 belonging to L. innocua (13.9%) and 6 to L. monocytogenes (2.9%). Oxacillin resistance was the most common resistance phenotype and was identified in 100% Listeria isolates. A medium prevalence of resistance to clindamycin (39.3% isolates) and low incidence of resistance to tetracycline (3.9% isolates) were also detected. Listeria isolates from RTE meat products displayed higher overall antimicrobial resistance (31.3%) than those from the environment (13.4%). All the strains assayed were sensitive to the preferred antibiotics used to treat listeriosis. Results showed that although antimicrobial resistance in L. monocytogenes still occurs at a low prevalence, L. innocua can form a reservoir of resistance genes which may transfer between bacterial species, including transference to organisms capable of causing disease in humans.

  17. Human Antimicrobial Peptides and Proteins

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2014-05-01

    Full Text Available As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32 can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized

  18. Bacteriological Analysis, Antimicrobial Susceptibility and Detection of 16S rRNA gene of Helicobacter pylori by PCR in Drinking Water Samples of Earthquake Affected Areas and Other Parts of Pakistan

    Directory of Open Access Journals (Sweden)

    Rasheed, F.

    2009-01-01

    Full Text Available In Pakistan, clean drinking water is not available to most of the population. Main source of drinking water in Hazara, Azad Jammu and Kashmir-Pakistan is underground and spring water, due to earthquake water reservoirs in these areas were immensely contaminated. Moreover, drinking water treatment and proper sanitary facilities were also lacking. This study was conducted to analyze the quality of drinking water available in most of the cities of Pakistan including earthquake hit areas. For this purpose, 112 water samples were collected and analyzed by membrane filtration method. Microbial isolates were identified using QTS-10 and biochemical tests. Almost all samples were found to be contaminated but in earthquake affected areas quality of drinking water was substandard than other areas of Pakistan. Results revealed the detection of following bacterial pathogens among the water samples: Enterobacter sp., Klebsiellasp., Stenotrophomonas sp., Salmonella sp., Proteus sp., Edwardsiella tarda, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Vibrio cholerae, Escherichia coli, Acinetobacter baumanii, Aeromonas hydrophila, Citrobacter freundii, Shigella dysenteriae, Staphylococcus aureus, Staphylococcus sp. and Streptococcus sp. Furthermore, these bacterial isolates were found to be resistant to ampicillin (32.1%, amoxicillin (30.4%, sulphometoxazole (20.5% and cefaclor (31.3%. All drinking water samples were analyzed for 16S rRNA gene of Helicobacter pylori by using PCR, however no positive result was found in these samples. Based on our results it is suggested that authorities should pay attention to supply safe water and proper sanitary facilities to avoid epidemics of infectious diseases in future.

  19. The roles of antimicrobial peptides in innate host defense.

    Science.gov (United States)

    Diamond, Gill; Beckloff, Nicholas; Weinberg, Aaron; Kisich, Kevin O

    2009-01-01

    Antimicrobial peptides (AMPs) are multi-functional peptides whose fundamental biological role in vivo has been proposed to be the elimination of pathogenic microorganisms, including Gram-positive and -negative bacteria, fungi, and viruses. Genes encoding these peptides are expressed in a variety of cells in the host, including circulating phagocytic cells and mucosal epithelial cells, demonstrating a wide range of utility in the innate immune system. Expression of these genes is tightly regulated; they are induced by pathogens and cytokines as part of the host defense response, and they can be suppressed by bacterial virulence factors and environmental factors which can lead to increased susceptibility to infection. New research has also cast light on alternative functionalities, including immunomodulatory activities, which are related to their unique structural characteristics. These peptides represent not only an important component of innate host defense against microbial colonization and a link between innate and adaptive immunity, but also form a foundation for the development of new therapeutic agents.

  20. Marine echinoderms as reservoirs of antimicrobial resistant bacteria

    Directory of Open Access Journals (Sweden)

    Catarina Marinho

    2014-06-01

    able to spread their genes into aquatic microorganisms, which may also contain resistance genes. Furthermore, it is known that several antibiotics from industrial sources circulate in water environments, potentially altering microbial ecosystems (Baquero et al., 2008. Once antibiotics enter the ecosystem, they can act as an ecological factor, eradicating susceptible and promoting resistant species and strains (Aminov and Mackie, 2007. The study of antibiotic resistance in aquatic organisms is pertinent, as it might indicate the variation amount of aquatic ecosystems with presumable human action. Aquatic environment play an important role in the spreading and evolution of antibiotic resistant bacteria. In this way, bacteria from different origins are able to interact, and antibiotic resistance improves as a consequence of uncontrolled exchange and shuffling of genes, genetic elements, and genetic vectors (Baquero et al., 2008. The need for monitoring and evaluate bacteria susceptibility to antibiotics in humans, animals and the environment is considered as a measure to contest the increasing of antimicrobial resistance (WHO, 2001. Enterococcus spp. and Escherichia coli mostly do not cause disease, but they may act as a reservoir of antimicrobial-resistance genes that could be transmitted to other pathogenic bacteria. In fact, both Enterococcus spp. and E. coli are experts in acquiring and transmitting resistance genes, even to phylogenetically distant bacteria, representing a worldwide concern (Martel et al., 2003, Costa et al., 2006. Enterococcus spp. is more frequently isolated from echinoderms fecal samples than E. coli bacteria, which may be due to the fact that E. coli are Gram-negative bacteria that typically are more susceptible to adverse conditions than Gram-positive bacteria (Marinho et al., 2013, Wan et al., 2009. The highest percentage of antibiotic resistance exhibited on enterococci isolates was to erythromycin, ampicillin, tetracycline, and ciprofloxacin

  1. Comparative evaluation of antimicrobials for textile applications.

    Science.gov (United States)

    Windler, Lena; Height, Murray; Nowack, Bernd

    2013-03-01

    Many antimicrobial technologies are available for textiles. They may be used in many different textile applications to prevent the growth of microorganisms. Due to the biological activity of the antimicrobial compounds, the assessment of the safety of these substances is an ongoing subject of research and regulatory scrutiny. This review aims to give an overview on the main compounds used today for antimicrobial textile functionalization. Based on an evaluation of scientific publications, market data as well as regulatory documents, the potential effects of antimicrobials on the environment and on human health were considered and also life cycle perspectives were taken into account. The characteristics of each compound were summarized according to technical, environmental and human health criteria. Triclosan, silane quaternary ammonium compounds, zinc pyrithione and silver-based compounds are the main antimicrobials used in textiles. The synthetic organic compounds dominate the antimicrobials market on a weight basis. On the technical side the application rates of the antimicrobials used to functionalize a textile product are an important parameter with treatments requiring lower dosage rates offering clear benefits in terms of less active substance required to achieve the functionality. The durability of the antimicrobial treatment has a strong influence on the potential for release and subsequent environmental effects. In terms of environmental criteria, all compounds were rated similarly in effective removal in wastewater treatment processes. The extent of published information about environmental behavior for each compound varies, limiting the possibility for an in-depth comparison of all textile-relevant parameters across the antimicrobials. Nevertheless the comparative evaluation showed that each antimicrobial technology has specific risks and benefits that should be taken into account in evaluating the suitability of different antimicrobial products. The

  2. Whole Genome Sequencing for Surveillance of Antimicrobial Resistance in Actinobacillus pleuropneumoniae

    Science.gov (United States)

    Bossé, Janine T.; Li, Yanwen; Rogers, Jon; Fernandez Crespo, Roberto; Li, Yinghui; Chaudhuri, Roy R.; Holden, Matthew T. G.; Maskell, Duncan J.; Tucker, Alexander W.; Wren, Brendan W.; Rycroft, Andrew N.; Langford, Paul R.

    2017-01-01

    The aim of this study was to evaluate the correlation between antimicrobial resistance (AMR) profiles of 96 clinical isolates of Actinobacillus pleuropneumoniae, an important porcine respiratory pathogen, and the identification of AMR genes in whole genome sequence (wgs) data. Susceptibility of the isolates to nine antimicrobial agents (ampicillin, enrofloxacin, erythromycin, florfenicol, sulfisoxazole, tetracycline, tilmicosin, trimethoprim, and tylosin) was determined by agar dilution susceptibility test. Except for the macrolides tested, elevated MICs were highly correlated to the presence of AMR genes identified in wgs data using ResFinder or BLASTn. Of the isolates tested, 57% were resistant to tetracycline [MIC ≥ 4 mg/L; 94.8% with either tet(B) or tet(H)]; 48% to sulfisoxazole (MIC ≥ 256 mg/L or DD = 6; 100% with sul2), 20% to ampicillin (MIC ≥ 4 mg/L; 100% with blaROB-1), 17% to trimethoprim (MIC ≥ 32 mg/L; 100% with dfrA14), and 6% to enrofloxacin (MIC ≥ 0.25 mg/L; 100% with GyrAS83F). Only 33% of the isolates did not have detectable AMR genes, and were sensitive by MICs for the antimicrobial agents tested. Although 23 isolates had MIC ≥ 32 mg/L for tylosin, all isolates had MIC ≤ 16 mg/L for both erythromycin and tilmicosin, and no macrolide resistance genes or known point mutations were detected. Other than the GyrAS83F mutation, the AMR genes detected were mapped to potential plasmids. In addition to presence on plasmid(s), the tet(B) gene was also found chromosomally either as part of a 56 kb integrative conjugative element (ICEApl1) in 21, or as part of a Tn7 insertion in 15 isolates. Our results indicate that, with the exception of macrolides, wgs data can be used to accurately predict resistance of A. pleuropneumoniae to the tested antimicrobial agents and provides added value for routine surveillance.

  3. Antimicrobial Stewardship: The Need to Cover All Bases

    OpenAIRE

    N Deborah Friedman

    2013-01-01

    Increasing antimicrobial resistance has necessitated an approach to guide the use of antibiotics. The necessity to guide antimicrobial use via stewardship has never been more urgent. The decline in anti-infective innovation and the failure of currently available antimicrobials to treat some serious infections forces clinicians to change those behaviors that drive antimicrobial resistance. The majority of antimicrobial stewardship (AMS) programs function in acute-care hospitals, however, hospi...

  4. Antimicrobial peptides of multicellular organisms

    Science.gov (United States)

    Zasloff, Michael

    2002-01-01

    Multicellular organisms live, by and large, harmoniously with microbes. The cornea of the eye of an animal is almost always free of signs of infection. The insect flourishes without lymphocytes or antibodies. A plant seed germinates successfully in the midst of soil microbes. How is this accomplished? Both animals and plants possess potent, broad-spectrum antimicrobial peptides, which they use to fend off a wide range of microbes, including bacteria, fungi, viruses and protozoa. What sorts of molecules are they? How are they employed by animals in their defence? As our need for new antibiotics becomes more pressing, could we design anti-infective drugs based on the design principles these molecules teach us?

  5. [Heterogenous expression of antimicrobial peptides].

    Science.gov (United States)

    Song, Shanshan; Hu, Guobin; Dong, Xianzhi

    2009-12-01

    Antimicrobial peptides (AMPs), a class of short proteins with a broad spectrum of antibacterial activities, are isolated from a wide variety of animals, both vertebrates and invertebrates, and plants as well as from bacteria and fungi. They are a key component of the innate immune response in most multicellular organisms. Owing to their potent, broad-spectrum antibacterial activities and uneasy developing of drug resistance, these peptides are of great clinical significance. However, preparation of AMPs at a large scale is a severe challenge to the development of the commercial products. Undoubtedly, construction of high-level biological expression systems for the production of AMPs is the key in its clinical application process. Herein, we summarize the progress in researches on heterogenous expression of AMPs in prokaryotic expression systems and eukaryotic expression systems.

  6. Antimicrobial resistance in typhoidal salmonellae

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    B N Harish

    2011-01-01

    Full Text Available Infections with Salmonella are an important public health problem worldwide. On a global scale, it has been appraised that Salmonella is responsible for an estimated 3 billion human infections each year. The World Health Organization (WHO has estimated that annually typhoid fever accounts for 21.7 million illnesses (217,000 deaths and paratyphoid fever accounts for 5.4 million of these cases. Infants, children, and adolescents in south-central and South-eastern Asia experience the greatest burden of illness. In cases of enteric fever, including infections with S. Typhi and S. Paratyphi A and B, it is often necessary to commence treatment before the results of laboratory sensitivity tests are available. Hence, it is important to be aware of options and possible problems before beginning treatment. Ciprofloxacin has become the first-line drug of choice since the widespread emergence and spread of strains resistant to chloramphenicol, ampicillin, and trimethoprim. There is increase in the occurrence of strains resistant to ciprofloxacin. Reports of typhoidal salmonellae with increasing minimum inhibitory concentration (MIC and resistance to newer quinolones raise the fear of potential treatment failures and necessitate the need for new, alternative antimicrobials. Extended-spectrum cephalosporins and azithromycin are the options available for the treatment of enteric fever. The emergence of broad spectrum β-lactamases in typhoidal salmonellae constitutes a new challenge. Already there are rare reports of azithromycin resistance in typhoidal salmonellae leading to treatment failure. This review is based on published research from our centre and literature from elsewhere in the world. This brief review tries to summarize the history and recent trends in antimicrobial resistance in typhoidal salmonellae.

  7. Antimicrobial peptides in human sepsis

    Directory of Open Access Journals (Sweden)

    Lukas eMartin

    2015-08-01

    Full Text Available Nearly 100 years ago, antimicrobial peptides (AMPs were identified as an important part of innate immunity. They exist in species from bacteria to mammals and can be isolated in body fluids and on surfaces constitutively or induced by inflammation. Defensins have anti-bacterial effects against Gram-positive and Gram-negative bacteria as well as anti-viral and anti-yeast effects. Human neutrophil peptides (HNP 1-3 and human beta-defensins (HBDs 1-3 are some of the most important defensins in humans. Recent studies have demonstrated higher levels of HNP -1-3 and HBD-2 in sepsis. The bactericidal/permeability increasing protein (BPI attenuates local inflammatory response and decreases systemic toxicity of endotoxins. Moreover, BPI might reflect the severity of organ dysfunction in sepsis. Elevated plasma lactoferrin is detected in patients with organ failure. HNP-1-3, lactoferrin, BPI and heparin-binding protein (HBP are increased in sepsis. Human lactoferrin peptide 1-11 (hLF 1-11 possesses antimicrobial activity and modulates inflammation. The recombinant form of lactoferrin (talactoferrin alpha, TLF has been shown to decrease mortality in critically ill patients. A phase II/III study with TLF in sepsis did not confirm this result. The growing number of multiresistant bacteria is an ongoing problem in sepsis therapy. Furthermore, antibiotics are known to promote the liberation of pro-inflammatory cell components and thus augment the severity of sepsis. Compared to antibiotics, AMPs kill bacteria but also neutralize pathogenic factors such as lipopolysaccharide (LPS. The obstacle to applying naturally occurring AMPs is their high nephro- and neurotoxicity. Therefore, the challenge is to develop peptides to treat septic patients effectively without causing harm. This overview focuses on natural and synthetic AMPs in human and experimental sepsis and their potential to provide significant improvements in the treatment of critically ill with severe

  8. Evolution of the avian β-defensin and cathelicidin genes

    OpenAIRE

    Cheng, Yuanyuan; Prickett, Michael Dennis; Gutowska, Maria; Kuo, Richard; Belov, Katherine; Burt, David W.

    2015-01-01

    Background β-defensins and cathelicidins are two families of cationic antimicrobial peptides (AMPs) with a broad range of antimicrobial activities that are key components of the innate immune system. Due to their important roles in host defense against rapidly evolving pathogens, the two gene families provide an ideal system for studying adaptive gene evolution. In this study we performed phylogenetic and selection analyses on β-defensins and cathelicidins from 53 avian species representing 3...

  9. Antimicrobial activity of some Iranian medicinal plants

    Directory of Open Access Journals (Sweden)

    Ghasemi Pirbalouti Abdollah

    2010-01-01

    Full Text Available The major aim of this study was to determine the antimicrobial activity of the extracts of eight plant species which are endemic in Iran. The antimicrobial activities of the extracts of eight Iranian traditional plants, including Hypericum scabrum, Myrtus communis, Pistachia atlantica, Arnebia euchroma, Salvia hydrangea, Satureja bachtiarica, Thymus daenensis and Kelussia odoratissima, were investigated against Escherichia coli O157:H7, Bacillus cereus, Listeria monocytogenes and Candida albicans by agar disc diffusion and serial dilution assays. Most of the extracts showed a relatively high antimicrobial activity against all the tested bacteria and fungi. Of the plants studied, the most active extracts were those obtained from the essential oils of M. communis and T. daenensis. The MIC values for active extract and essential oil ranged between 0.039 and 10 mg/ml. It can be said that the extract and essential oil of some medicinal plants could be used as natural antimicrobial agents in food preservation. .

  10. SecA inhibitors: next generation antimicrobials

    Institute of Scientific and Technical Information of China (English)

    Weixuan Chen; Arpana Chaudhary; Jianmei Cui; Jinshan Jin; Yinghsin Hsieh; Hsiuchin Yang; Yingju Huang; Phang C. Tai; Binghe Wang

    2012-01-01

    Health problems caused by bacterial infection have become a major public health concern in recent years due to the widespread emergence of drug-resistant bacterial strains.Therefore,the need for the development of new types of antimicrobial agents,especially those with a novel mechanism of action,is urgent.SecA,one of the key components of the secretion (Sec) pathway,is a new promising target for antimicrobial agent design.In recent years,promising leads targeting SecA have been identified and the feasibility of developing antimicrobial agents through the inhibition of SecA has been demonstrated.We hope this review will help stimulate more research in this area so that new antimicrobials can be obtained by targeting SecA.

  11. Antimicrobial activity of Gymnema sylvestre (Asclepiadaceae

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    Beverly C. David

    2013-01-01

    Conclusions: The dried scale leaves of G. sylvestre might represent a new antimicrobial source with stable, biologically active components that can establish a scientific base for the use in modern medicine.

  12. Antimicrobial-Coated Granules for Disinfecting Water

    Science.gov (United States)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

  13. The first salamander defensin antimicrobial peptide.

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    Ping Meng

    Full Text Available Antimicrobial peptides have been widely identified from amphibian skins except salamanders. A novel antimicrobial peptide (CFBD was isolated and characterized from skin secretions of the salamander, Cynops fudingensis. The cDNA encoding CFBD precursor was cloned from the skin cDNA library of C. fudingensis. The precursor was composed of three domains: signal peptide of 17 residues, mature peptide of 41 residues and intervening propeptide of 3 residues. There are six cysteines in the sequence of mature CFBD peptide, which possibly form three disulfide-bridges. CFBD showed antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli. This peptide could be classified into family of β-defensin based on its sequence similarity with β-defensins from other vertebrates. Evolution analysis indicated that CFBD was close to fish β-defensin. As far as we know, CFBD is the first β-defensin antimicrobial peptide from salamanders.

  14. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

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    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  15. Antimicrobial screening of Cichorium intybus seed extracts

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    Tauseef shaikh

    2016-11-01

    Full Text Available Medicinal plants play an important role in the field of natural products and human health care system. Chemical constituents present in the various parts of the plants can resist to parasitic attack by using several defense mechanisms. One such mechanism is the synthesis of antimicrobial compound. Cichorium intybus is one of the important medicinal plants which belong to Asteraceae family. In the present work, antimicrobial screening of C. intybus seed extract was studied by agar well diffusion assay by using aqueous and organic extracts. The pathogenic microorganisms tested include Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Escherichia coli. All the seed extracts showed antimicrobial activity against tested microorganisms whereas S. aureus was found to be most sensitive against aqueous extract and had the widest zone of inhibition. Ethyl acetate and ethanol extract were found to be significant against P. aeruginosa and S. aureus. The results obtained from antimicrobial screening scientifically support the effectiveness of the medicinal plant.

  16. Comparing antimicrobial exposure based on sales data

    DEFF Research Database (Denmark)

    Bondt, Nico; Jensen, Vibeke Frøkjær; Puister-Jansen, Linda F.

    2013-01-01

    This paper explores the possibilities of making meaningful comparisons of the veterinary use of antimicrobial agents among countries, based on national total sales data. Veterinary antimicrobial sales data on country level and animal census data in both Denmark and the Netherlands were combined...... incidences calculated from detailed use data per animal species from the national surveillance programmes in these two countries, to assess their accuracy and relevancy.In Denmark and in the Netherlands, although the computed antimicrobial exposure would seem to be a reasonable estimation of the exposure...... influenced by animal demographics and a very inaccurate indication of the true differences in exposure, per animal species. To get an appropriate certainty about the true differences in antimicrobial exposure between countries it is an absolute necessity to have reliable information about the use per animal...

  17. In vitro assessment of the antimicrobial susceptibility of caprine isolates of Mycoplasma mycoides subsp. capri.

    Science.gov (United States)

    Paterna, A; Tatay-Dualde, J; Amores, J; Prats-van der Ham, M; Sánchez, A; de la Fe, C; Contreras, A; Corrales, J C; Gómez-Martín, Á

    2016-08-01

    The minimum inhibitory concentration (MIC) and minimum mycoplasmacidal concentration (MMC) of 17 antimicrobials against 41 Spanish caprine isolates of Mycoplasma mycoides subsp. capri (Mmc) obtained from different specimens (milk, external auricular canal and semen) were determined using a liquid microdilution method. For half of the isolates, the MIC was also estimated for seven of the antimicrobials using an epsilometric test (ET), in order to compare both methods and assess the validity of ET. Mutations in genes gyrA, gyrB, parC and parE conferring fluoroquinolone resistance, which have been recently described in Mmc, were investigated using PCR. The anatomical origin of the isolate had no effect on its antimicrobial susceptibility. Moxifloxacin and doxycycline had the lowest MIC values. The rest of the fluoroquinolones studied (except norfloxacin), together with tylosin and clindamycin, also had low MIC values, although the MMC obtained for clindamycin was higher than for the other antimicrobials. For all the aminoglycosides, spiramycin and erythromycin, a notable level of resistance was observed. The ET was in close agreement with broth microdilution at low MICs, but not at intermediate or high MICs. The analysis of the genomic sequences revealed the presence of an amino acid substitution in codon 83 of the gene gyrA, which has not been described previously in Mmc.

  18. Oral biofilms: a reservoir of transferable, bacterial, antimicrobial resistance.

    Science.gov (United States)

    Roberts, Adam P; Mullany, Peter

    2010-12-01

    Oral microbes are responsible for dental caries and periodontal diseases and have also been implicated in a range of other diseases beyond the oral cavity. These bacteria live primarily as complex, polymicrobial biofilms commonly called dental plaque. Cells growing within a biofilm often exhibit altered phenotypes, such as increased antibiotic resistance. The stable structural properties and close proximity of the bacterial cells within the biofilm appears to be an excellent environment for horizontal gene transfer, which can lead to the spread of antibiotic resistance genes amongst the biofilm inhabitants. This article will present an overview of the different types and amount of resistance to antibiotics that have been found in the human oral microbiota and will discuss the oral inhabitants' role as a reservoir of antimicrobial resistance genes. In addition, data on the genetic support for these resistance genes will be detailed and the evidence for horizontal gene transfer reviewed, demonstrating that the bacteria inhabiting the oral cavity are a reservoir of transferable antibiotic resistance.

  19. Microarray Evaluation of Antimicrobial Resistance and Virulence of Escherichia coli Isolates from Portuguese Poultry

    Directory of Open Access Journals (Sweden)

    Nuno Mendonça

    2016-01-01

    Full Text Available The presence of antimicrobial resistance and virulence factors of 174 Escherichia coli strains isolated from healthy Portuguese Gallus gallus was evaluated. Resistance profiles were determined against 33 antimicrobials by microbroth dilution. Resistance was prevalent for tetracycline (70% and ampicillin (63%. Extended-spectrum beta-lactamase (ESBL phenotype was observed in 18% of the isolates. Multidrug resistance was found in 56% of isolates. A subset of 74 isolates were screened by DNA microarrays for the carriage of 88 antibiotic resistance genes and 62 virulence genes. Overall, 37 different resistance genes were detected. The most common were tet(A (72%, blaTEM (68%, and sul1 (47%, while 21% isolates harbored an ESBL gene (blaCTX-M group 1, group 2, or group 9. Of these, 96% carried the increased serum survival (iss virulence gene, while 89% presented the enterobactin siderophore receptor protein (iroN, 70% the temperature-sensitive hemagglutinin (tsh, and 68% the long polar fimbriae (lpfA virulence genes associated with extraintestinal pathogenic E. coli. In conclusion, prevalence of antibiotic resistant E. coli from the microbiota of Portuguese chickens was high, including to extended spectrum cephalosporins. The majority of isolates seems to have the potential to trigger extraintestinal human infection due to the presence of some virulence genes. However, the absence of genes specific for enteropathogenic E. coli reduces the risk for human intestinal infection.

  20. Antimicrobial activity of Tridax procumbens leaf

    OpenAIRE

    S. Santhosh Kumar; John, R.; G.Lakshmi Narayanan

    2015-01-01

    Estimation of the antimicrobial property of Tridax procumbens’s leaf was carried out by the use of chloroform, petroleum ether, ethyl alcohol and hexaneas solvents. Leaf extract of Tridax procumbens obtained by soxhlet extractor, using the above mentioned solvents were examined against Escherichia coli, Bacillus subtilis, and Pseudomonas vulgaris. The antimicrobial activity of Tridax procumbens performed by using agarwell diffusion method showed a result showcasing an effective limit when as ...

  1. Remote Antimicrobial Stewardship in Community Hospitals

    OpenAIRE

    Zachary H. Wood; Nicolsen, Nicole C.; Nichole Allen; Cook, Paul P.

    2015-01-01

    Antimicrobial stewardship has become standard practice at university medical centers, but the practice is more difficult to implement in remote community hospitals that lack infectious diseases trained practitioners. Starting in 2011, six community hospitals within the Vidant Health system began an antimicrobial stewardship program utilizing pharmacists who reviewed charts remotely from Vidant Medical Center. Pharmacists made recommendations within the electronic medical record (EMR) to strea...

  2. Antimicrobials of Bacillus species: mining and engineering

    OpenAIRE

    Zhao, Xin

    2016-01-01

    Bacillus sp. have been successfully used to suppress various bacterial and fungal pathogens. Due to the wide availability of whole genome sequence data and the development of genome mining tools, novel antimicrobials are being discovered and updated,;not only bacteriocins, but also NRPs and PKs. A new classification system of known and putative antimicrobial compounds of Bacillus by genome mining is presented in Chapter 2. Importantly, predicting, isolating and screening of Bacillus strains w...

  3. Structure-Activity Relationships of the Antimicrobial Peptide Arasin 1 — And Mode of Action Studies of the N-Terminal, Proline-Rich Region

    Science.gov (United States)

    Paulsen, Victoria S.; Blencke, Hans-Matti; Benincasa, Monica; Haug, Tor; Eksteen, Jacobus J.; Styrvold, Olaf B.; Scocchi, Marco; Stensvåg, Klara

    2013-01-01

    Arasin 1 is a 37 amino acid long proline-rich antimicrobial peptide isolated from the spider crab, Hyas araneus. In this work the active region of arasin 1 was identified through structure-activity studies using different peptide fragments derived from the arasin 1 sequence. The pharmacophore was found to be located in the proline/arginine-rich NH2 terminus of the peptide and the fragment arasin 1(1–23) was almost equally active to the full length peptide. Arasin 1 and its active fragment arasin 1(1–23) were shown to be non-toxic to human red blood cells and arasin 1(1–23) was able to bind chitin, a component of fungal cell walls and the crustacean shell. The mode of action of the fully active N-terminal arasin 1(1–23) was explored through killing kinetic and membrane permeabilization studies. At the minimal inhibitory concentration (MIC), arasin 1(1–23) was not bactericidal and had no membrane disruptive effect. In contrast, at concentrations of 5×MIC and above it was bactericidal and interfered with membrane integrity. We conclude that arasin 1(1–23) has a different mode of action than lytic peptides, like cecropin P1. Thus, we suggest a dual mode of action for arasin 1(1–23) involving membrane disruption at peptide concentrations above MIC, and an alternative mechanism of action, possibly involving intracellular targets, at MIC. PMID:23326415

  4. Structure-activity relationships of the antimicrobial peptide arasin 1 - and mode of action studies of the N-terminal, proline-rich region.

    Directory of Open Access Journals (Sweden)

    Victoria S Paulsen

    Full Text Available Arasin 1 is a 37 amino acid long proline-rich antimicrobial peptide isolated from the spider crab, Hyas araneus. In this work the active region of arasin 1 was identified through structure-activity studies using different peptide fragments derived from the arasin 1 sequence. The pharmacophore was found to be located in the proline/arginine-rich NH(2 terminus of the peptide and the fragment arasin 1(1-23 was almost equally active to the full length peptide. Arasin 1 and its active fragment arasin 1(1-23 were shown to be non-toxic to human red blood cells and arasin 1(1-23 was able to bind chitin, a component of fungal cell walls and the crustacean shell. The mode of action of the fully active N-terminal arasin 1(1-23 was explored through killing kinetic and membrane permeabilization studies. At the minimal inhibitory concentration (MIC, arasin 1(1-23 was not bactericidal and had no membrane disruptive effect. In contrast, at concentrations of 5×MIC and above it was bactericidal and interfered with membrane integrity. We conclude that arasin 1(1-23 has a different mode of action than lytic peptides, like cecropin P1. Thus, we suggest a dual mode of action for arasin 1(1-23 involving membrane disruption at peptide concentrations above MIC, and an alternative mechanism of action, possibly involving intracellular targets, at MIC.

  5. Structure-activity relationships of the antimicrobial peptide arasin 1 - and mode of action studies of the N-terminal, proline-rich region.

    Science.gov (United States)

    Paulsen, Victoria S; Blencke, Hans-Matti; Benincasa, Monica; Haug, Tor; Eksteen, Jacobus J; Styrvold, Olaf B; Scocchi, Marco; Stensvåg, Klara

    2013-01-01

    Arasin 1 is a 37 amino acid long proline-rich antimicrobial peptide isolated from the spider crab, Hyas araneus. In this work the active region of arasin 1 was identified through structure-activity studies using different peptide fragments derived from the arasin 1 sequence. The pharmacophore was found to be located in the proline/arginine-rich NH(2) terminus of the peptide and the fragment arasin 1(1-23) was almost equally active to the full length peptide. Arasin 1 and its active fragment arasin 1(1-23) were shown to be non-toxic to human red blood cells and arasin 1(1-23) was able to bind chitin, a component of fungal cell walls and the crustacean shell. The mode of action of the fully active N-terminal arasin 1(1-23) was explored through killing kinetic and membrane permeabilization studies. At the minimal inhibitory concentration (MIC), arasin 1(1-23) was not bactericidal and had no membrane disruptive effect. In contrast, at concentrations of 5×MIC and above it was bactericidal and interfered with membrane integrity. We conclude that arasin 1(1-23) has a different mode of action than lytic peptides, like cecropin P1. Thus, we suggest a dual mode of action for arasin 1(1-23) involving membrane disruption at peptide concentrations above MIC, and an alternative mechanism of action, possibly involving intracellular targets, at MIC.

  6. The antimicrobial possibilities of green tea

    Directory of Open Access Journals (Sweden)

    Wanda C Reygaert

    2014-08-01

    Full Text Available Green tea is a popular drink, especially in Asian countries, although its popularity continues to spread across the globe. The health benefits of green tea, derived from the leaves of the Camellia sinensis plant, have been studied for many years. Fairly recently, researchers have begun to look at the possibility of using green tea in antimicrobial therapy, and the potential prevention of infections. The particular properties of catechins found in the tea have shown promise for having antimicrobial effects. There are four main catechins (polyphenols found in green tea: (--epicatechin (EC, (--epicatechin-3-gallate (ECG, (--epigallocatechin (EGC, and (--epigallocatechin-3-gallate (EGCG. Three of these, ECG, EGC, and EGCG have been shown to have antimicrobial effects against a variety of organisms. These catechins have exhibited a variety of antimicrobial mechanisms. The results of studies on the antimicrobial effects of green tea have shown that the potential for preventive and therapeutic purposes is present. Further data collection on studies performed with human consumption during the course of infections, and studies on the occurrence of infections in populations that consume regular amounts of green tea will be necessary to complete the picture of its antimicrobial possibilities.

  7. The Scottish approach to enhancing antimicrobial stewardship.

    Science.gov (United States)

    Nathwani, Dilip; Christie, Peter

    2007-08-01

    In 2002, the Scottish Executive produced the Antimicrobial Resistance Strategy and Scottish Action Plan, which highlighted antimicrobial stewardship as a key objective in combating resistance. An important response, as a part of the Ministerial Healthcare Associated Infection Task Force work programme was the publication of 'Antimicrobial Prescribing Policy and Practice in Scotland: recommendations for good antimicrobial practice in acute hospitals' in 2005. This article briefly reviews the core components of the Scottish approach, reviews progress with some key goals and explores how many of these goals are being taken forward through a cohesive Scottish national multifaceted strategy, which incorporates primary and secondary care. Much of this will spring from the current review of the Scottish Action Plan. While recognizing the significant progress achieved by the Appropriate Antimicrobial Prescribing for Tomorrow's Doctors Project Group in the education of undergraduate medical students, the article also reviews the NHS Education Scotland-supported Scottish National Antimicrobial Prescribing Project, aimed at foundation training doctors in Scotland. We hope that this experience can be shared and further developed with colleagues within the United Kingdom and European Union.

  8. Antimicrobial and osteogenic effect of Ag-implanted titanium with a nanostructured surface

    Directory of Open Access Journals (Sweden)

    Zheng Y

    2012-02-01

    Full Text Available Yanhua Zheng1, Jinbo Li2, Xuanyong Liu2, Jiao Sun11Shanghai Biomaterials Research and Testing Center, Shanghai Key Laboratory of Stomatology, Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, People’s Republic of China; 2State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People’s Republic of ChinaAbstract: Ag-implanted titanium with a nanostructured surface was prepared by hydrothermal treatment with H2O2 followed by Ag plasma immersion ion implantation. Streptococcus mutans, Porphyromonas gingivalis and Candida albicans were chosen for antimicrobial tests. Genes related to microbial structure or adhesion, namely glucan-binding proteins B (GbpB, fimbria protein A (FimA, and agglutinin-like sequence4 (Als4, were examined. The osteoblast’s attachment, viability, and quantitative analysis of osteogenic gene expression (Alp, Ocn, RunX2 on titanium surfaces were evaluated. Scanning electron microscopy (SEM revealed that Ag nanoparticles of approximately 10 nm were incorporated on the nanostructured surface of titanium after Ag plasma immersion ion implantation. Trials showed that 93.99% of S. mutans, 93.57% of P. g, and 89.78% of C. albicans were killed on the Ag-implanted titanium with a nanostructured surface. Gene expressions from the three microorganisms confirmed the antimicrobial activities of the Ag-implanted titanium with a nanostructured surface. Furthermore, the adhesive images and viability assays indicated that the Ag-implanted titanium with a nanostructured surface did not impair osteoblasts. The expressions of osteoblast phenotype genes in cells grown on the Ag-implanted titanium surface were significantly increased. The results of this study suggest that the Ag-implanted titanium with a nanostructured surface displays good antimicrobial properties, reducing gene expressions of

  9. Danish integrated antimicrobial in resistance monitoring and research program

    DEFF Research Database (Denmark)

    Hammerum, Anette Marie; Heuer, Ole Eske; Emborg, Hanne-Dorthe

    2007-01-01

    Resistance to antimicrobial agents is an emerging problem worldwide. Awareness of the undesirable consequences of its widespread occurrence has led to the initiation of antimicrobial agent resistance monitoring programs in several countries. In 1995, Denmark was the first country to establish a s...... activities related to DANMAP have contributed to restrictions or bans of use of several antimicrobial agents in food animals in Denmark and other European Union countries....... a systematic and continuous monitoring program of antimicrobial drug consumption and antimicrobial agent resistance in animals, food, and humans, the Danish Integrated Antimicrobial Resistance Monitoring and Research Program (DANMAP). Monitoring of antimicrobial drug resistance and a range of research......Resistance to antimicrobial agents is an emerging problem worldwide. Awareness of the undesirable consequences of its widespread occurrence has led to the initiation of antimicrobial agent resistance monitoring programs in several countries. In 1995, Denmark was the first country to establish...

  10. Prevalence and Antimicrobial Resistance of Enterococcus Species: A Hospital-Based Study in China

    Directory of Open Access Journals (Sweden)

    Wei Jia

    2014-03-01

    Full Text Available Objective: to investigate the prevalence and antimicrobial resistance of Enterococcus species isolated from a university hospital, and explore the mechanisms underlying the antimicrobial resistance, so as to provide clinical evidence for the inappropriate clinical use of antimicrobial agents and the control and prevention of enterococcal infections. Methods: a total of 1,157 enterococcal strains isolated from various clinical specimens from January 2010 to December 2012 in the General Hospital of Ningxia Medical University were identified to species level with a VITEK-2 COMPACT fully automated microbiological system, and the antimicrobial susceptibility of Enterococcus species was determined using the Kirby-Bauer disc diffusion method. The multiple-drug resistant enterococcal isolates were screened from the clinical isolates of Enterococcus species from the burns department. The minimal inhibitory concentration (MIC of Enterococcus species to the three fluoroquinolones, including ciprofloxacin, gatifloxacin and levofloxacin was determined with the agar dilution method, and the changes in the MIC of Enterococcus species to the three fluoroquinolones following reserpine treatment were evaluated. The β-lactam, aminoglycoside, tetracycline, macrolide, glycopeptide resistance genes and the efflux pump emeA genes were detected in the enterococcal isolates using a polymerase chain reaction (PCR assay. Results: the 1,157 clinical isolates of Enterococcus species included 679 E. faecium isolates (58.7%, 382 E. faecalis isolates (33%, 26 E. casseliflavus isolates (2.2%, 24 E. avium isolates (2.1%, and 46 isolates of other Enterococcus species (4%. The prevalence of antimicrobial resistance varied significantly between E. faecium and E. faecalis, and ≤1.1% of these two Enterococcus species were found to be resistant to vancomycin, teicoplanin or linezolid. In addition, the Enterococcus species isolated from different departments of the hospital

  11. Use of Aeromonas spp. as general indicators of antimicrobial susceptibility among bacteria in aquatic environments in Thailand

    Directory of Open Access Journals (Sweden)

    Masaru eUsui

    2016-05-01

    Full Text Available Antimicrobials are widely used, not only for treating human infections, but also for treatment of livestock and in fish farms. Human habitats in Southeastern Asian countries are located in close proximity to aquatic environments. As such, the human populations within these regions are at risk of exposure to antimicrobial resistant bacteria (ARB, and thereby disseminating antimicrobial resistance genes (ARGs. In this study, we collected water samples from 15 sites (5 sites in Chao Phraya River, 2 sites at the mouth of Chao Phraya River, 3 sites in Ta Chin River, and 5 sites at city canals and 12 sites (6 sites at city canals, 2 sites at chicken farms, 2 sites at pig farms, and 2 samples from sites at pig farms that were subsequently treated at a biogas plant in Thailand in 2013 and 2014, respectively. In total, 117 Aeromonas spp. were isolated from the water samples, and these organisms exhibited various antimicrobial susceptibility profiles. Moreover, there was a significant correlation between the environmental concentration of tetracyclines and the rates of tetracycline resistance in the isolated Aeromonas spp. Notably, however, the concentration and resistance rates of tetracycline in samples derived from pig farms were higher than those of samples harvested from other aquatic environments. These findings suggest that the high concentrations of antimicrobials observed in these aquatic environments likely select for ARGs. Furthermore, they indicate that Aeromonas spp. comprise an effective marker for monitoring antimicrobial resistance in aquatic environments.

  12. Use of Aeromonas spp. as General Indicators of Antimicrobial Susceptibility among Bacteria in Aquatic Environments in Thailand.

    Science.gov (United States)

    Usui, Masaru; Tagaki, Chie; Fukuda, Akira; Okubo, Torahiko; Boonla, Chanchai; Suzuki, Satoru; Seki, Kanako; Takada, Hideshige; Tamura, Yutaka

    2016-01-01

    Antimicrobials are widely used, not only for treating human infections, but also for treatment of livestock and in fish farms. Human habitats in Southeastern Asian countries are located in close proximity to aquatic environments. As such, the human populations within these regions are at risk of exposure to antimicrobial resistant bacteria, and thereby disseminating antimicrobial resistance genes (ARGs). In this study, we collected water samples from 15 sites (5 sites in Chao Phraya River, 2 sites at the mouth of Chao Phraya River, 3 sites in Ta Chin River, and 5 sites at city canals) and 12 sites (6 sites at city canals; 2 sites at chicken farms; 2 sites at pig farms; and 2 samples from sites at pig farms, which were subsequently treated at a biogas plant) in Thailand in 2013 and 2014, respectively. In total, 117 Aeromonas spp. were isolated from the water samples, and these organisms exhibited various antimicrobial susceptibility profiles. Notably, there was a significant correlation between the environmental concentration of tetracyclines and the rates of tetracycline resistance in the isolated Aeromonas spp.; however, both the concentration and rates of tetracycline resistance in samples derived from pig farms were higher than those of samples harvested from other aquatic environments. These findings suggest that the high concentrations of antimicrobials observed in these aquatic environments likely select for ARGs. Furthermore, they indicate that Aeromonas spp. comprise an effective marker for monitoring antimicrobial resistance in aquatic environments.

  13. The role of antimicrobial peptides in animal defenses

    Science.gov (United States)

    Hancock, Robert E. W.; Scott, Monisha G.

    2000-08-01

    It is becoming clear that the cationic antimicrobial peptides are an important component of the innate defenses of all species of life. Such peptides can be constitutively expressed or induced by bacteria or their products. The best peptides have good activities vs. a broad range of bacterial strains, including antibiotic-resistant isolates. They kill very rapidly, do not easily select resistant mutants, are synergistic with conventional antibiotics, other peptides, and lysozyme, and are able to kill bacteria in animal models. It is known that bacterial infections, especially when treated with antibiotics, can lead to the release of bacterial products such as lipopolysaccharide (LPS) and lipoteichoic acid, resulting in potentially lethal sepsis. In contrast to antibiotics, the peptides actually prevent cytokine induction by bacterial products in tissue culture and human blood, and they block the onset of sepsis in mouse models of endotoxemia. Consistent with this, transcriptional gene array experiments using a macrophage cell line demonstrated that a model peptide, CEMA, blocks the expression of many genes whose transcription was induced by LPS. The peptides do this in part by blocking LPS interaction with the serum protein LBP. In addition, CEMA itself has a direct effect on macrophage gene expression. Because cationic antimicrobial peptides are induced by LPS and are able to dampen the septic response of animal cells to LPS, we propose that, in addition to their role in direct and lysozyme-assisted killing of microbes, they have a role in feedback regulation of cytokine responses. We are currently developing variant peptides as therapeutics against antibiotic-resistant infections.

  14. Improving antimicrobial prescribing: implementation of an antimicrobial i.v.-to-oral switch policy.

    Science.gov (United States)

    McCallum, A D; Sutherland, R K; Mackintosh, C L

    2013-01-01

    Antimicrobial stewardship programmes reduce the risk of hospital associated infections (HAI) and antimicrobial resistance, and include early intravenous-to-oral switch (IVOS) as a key stewardship measure. We audited the number of patients on intravenous antimicrobials suitable for oral switch, assessed whether prescribing guidelines were followed and reviewed prescribing documentation in three clinical areas in the Western General Hospital, Edinburgh, in late 2012. Following this, the first cycle results and local guidelines were presented at a local level and at the hospital grand rounds, posters with recommendations were distributed, joint infection consult and antimicrobial rounds commenced and an alert antimicrobial policy was introduced before re-auditing in early 2013. We demonstrate suboptimal prescribing of intravenous antimicrobials, with 43.9% (43/98) of patients eligible for IVOS at the time of auditing. Only 56.1% (55/98) followed empiric prescribing recommendations. Documentation of antimicrobial prescribing was poor with stop dates recorded in 14.3%, indication on prescription charts in 18.4% and in the notes in 90.8%. The commonest reason for deferring IVOS was deteriorating clinical condition or severe sepsis. Further work to encourage prudent antimicrobial prescribing and earlier consideration of IVOS is required.

  15. Review of immobilized antimicrobial agents and methods for testing.

    Science.gov (United States)

    Green, John-Bruce D; Fulghum, Timothy; Nordhaus, Mark A

    2011-12-01

    Antimicrobial surfaces for food and medical applications have historically involved antimicrobial coatings that elute biocides for effective kill in solution or at surfaces. However, recent efforts have focused on immobilized antimicrobial agents in order to avoid toxicity and the compatibility and reservoir limitations common to elutable agents. This review critically examines the assorted antimicrobial agents reported to have been immobilized, with an emphasis on the interpretation of antimicrobial testing as it pertains to discriminating between eluting and immobilized agents. Immobilization techniques and modes of antimicrobial action are also discussed.

  16. Prevalence and Antimicrobial Resistance of Campylobacter Isolated from Dressed Beef Carcasses and Raw Milk in Tanzania.

    Science.gov (United States)

    Kashoma, Isaac P; Kassem, Issmat I; John, Julius; Kessy, Beda M; Gebreyes, Wondwossen; Kazwala, Rudovick R; Rajashekara, Gireesh

    2016-01-01

    Campylobacter species are commonly transmitted to humans through consumption of contaminated foods such as milk and meat. The aim of this study was to investigate the prevalence, antimicrobial resistance, and genetic determinants of resistance of Campylobacter isolated from raw milk and beef carcasses in Tanzania. The antimicrobial resistance genes tested included blaOXA-61 (ampicillin), aph-3-1 (aminoglycoside), tet(O) (tetracycline), and cmeB (multi-drug efflux pump). The prevalence of Campylobacter was 9.5% in beef carcasses and 13.4% in raw milk, respectively. Using multiplex-polymerase chain reaction (PCR), we identified 58.1% of the isolates as Campylobacter jejuni, 30.7% as Campylobacter coli, and 9.7% as other Campylobacter spp. One isolate (1.6%) was positive for both C. jejuni and C. coli specific PCR. Antimicrobial susceptibility testing using the disk diffusion assay and the broth microdilution method showed resistance to: ampicillin (63% and 94.1%), ciprofloxacin (9.3% and 11.8%), erythromycin (53.7% and 70.6%), gentamicin (0% and 15.7%), streptomycin (35.2% and 84.3%), and tetracycline (18.5% and 17.7%), respectively. Resistance to azithromycin (42.6%), nalidixic acid (64.8%), and chloramphenicol (13%) was determined using the disk diffusion assay only, while resistance to tylosin (90.2%) was quantified using the broth microdilution method. The blaOXA-61 (52.6% and 28.1%), cmeB (26.3% and 31.3%), tet(O) (26.3% and 31.3%), and aph-3-1 (5.3% and 3.0%) were detected in C. coli and C. jejuni. These findings highlight the extent of antimicrobial resistance in Campylobacter occurring in important foods in Tanzania. The potential risks to consumers emphasize the need for adequate control approaches, including the prudent use of antimicrobials to minimize the spread of antimicrobial-resistant Campylobacter.

  17. Salmonella contamination, serovars and antimicrobial resistance profiles of cattle slaughtered in South Africa.

    Science.gov (United States)

    Madoroba, Evelyn; Kapeta, Daniel; Gelaw, Awoke K

    2016-05-26

    Antimicrobial resistant Salmonella are among the leading causes of foodborne infections. Our aim was to determine Salmonella contamination during cattle slaughter in South African rural abattoirs (n = 23) and environmental samples. Furthermore, antimicrobial resistance patterns of the Salmonella isolates were determined. Samples of cattle faeces (n = 400), carcass sponges (n = 100), intestinal contents (n = 62), hides (n = 67), and water from the abattoirs (n = 75) were investigated for Salmonella species using microbiological techniques and species-specific polymerase chain reaction targeting the invA gene. In total 92 Salmonella species isolates were recovered. The Salmonella mean frequency of occurrence on hides, carcasses, and intestinal contents was 35.37% (n = 81). Eleven faecal samples (2.75%) tested positive for Salmonella. The predominant serovar was Salmonella Enteritidis. Diverse serovars that were identified on carcasses were not necessarily found on the hides and intestinal contents. The inconsistent occurrence of the diverse Salmonella serovars on hides, carcasses, and intestinal contents implies that in addition to carriage on hides and in intestinal contents, other external factors also play an important role regarding carcass contamination. The 92 Salmonella were serotyped and tested for susceptibility towards the following antimicrobials: ampicillin, cefotaxime, enrofloxacin, kanamycin, and oxytetracycline using the disk diffusion method. Most Salmonella (n = 66; 71.7%) isolates were resistant to at least one antimicrobial with highest resistance observed towards oxytetracycline (51.90%), which highlights the need for strict hygiene during slaughter and prudent antimicrobial use during animal production. In conclusion, cattle slaughtered in South African rural abattoirs harbour diverse Salmonella serovars that are resistant to antimicrobials, which could be a public health risk. The findings should assist policymakers with improving implementation

  18. Bacterial flora and antimicrobial resistance in raw frozen cultured seafood imported to Denmark.

    Science.gov (United States)

    Noor Uddin, Gazi M; Larsen, Marianne Halberg; Guardabassi, Luca; Dalsgaard, Anders

    2013-03-01

    Intensified aquaculture includes the use of antimicrobials for disease control. In contrast to the situation in livestock, Escherichia coli and enterococci are not part of the normal gastrointestinal flora of fish and shrimp and therefore not suitable indicators of antimicrobial resistance in seafood. In this study, the diversity and phenotypic characteristics of the bacterial flora in raw frozen cultured and wild-caught shrimp and fish were evaluated to identify potential indicators of antimicrobial resistance. The bacterial flora cultured on various agar media at different temperatures yielded total viable counts of 4.0 × 10(4) to 3.0 × 10(5) CFU g(-1). Bacterial diversity was indicated by 16S rRNA sequence analysis of 84 isolates representing different colony types; 24 genera and 51 species were identified. Pseudomonas spp. (23% of isolates), Psychrobacter spp. (17%), Serratia spp. (13%), Exiguobacterium spp. (7%), Staphylococcus spp. (6%), and Micrococcus spp. (6%) dominated. Disk susceptibility testing of 39 bacterial isolates to 11 antimicrobials revealed resistance to ampicillin, amoxicillin-clavulanic acid, erythromycin, and third generation cephalosporins. Resistance to third generation cephalosporins was found in Pseudomonas, a genus naturally resistant to most β-lactam antibiotics, and in Staphylococcus hominis. Half of the isolates were susceptible to all antimicrobials tested. Results indicate that identification of a single bacterial resistance indicator naturally present in seafood at point of harvest is unlikely. The bacterial flora found likely represents a processing rather than a raw fish flora because of repeated exposure of raw material to water during processing. Methods and appropriate indicators, such as quantitative PCR of resistance genes, are needed to determine how antimicrobials used in aquaculture affect resistance of bacteria in retailed products.

  19. Salmonella contamination, serovars and antimicrobial resistance profiles of cattle slaughtered in South Africa

    Directory of Open Access Journals (Sweden)

    Evelyn Madoroba

    2016-03-01

    Full Text Available Antimicrobial resistant Salmonella are among the leading causes of foodborne infections. Our aim was to determine Salmonella contamination during cattle slaughter in South African rural abattoirs (n = 23 and environmental samples. Furthermore, antimicrobial resistance patterns of the Salmonella isolates were determined. Samples of cattle faeces (n = 400, carcass sponges (n = 100, intestinal contents (n = 62, hides (n = 67, and water from the abattoirs (n = 75 were investigated for Salmonella species using microbiological techniques and species-specific polymerase chain reaction targeting the invA gene. In total 92 Salmonella species isolates were recovered. The Salmonella mean frequency of occurrence on hides, carcasses, and intestinal contents was 35.37% (n = 81. Eleven faecal samples (2.75% tested positive for Salmonella. The predominant serovar was Salmonella Enteritidis. Diverse serovars that were identified on carcasses were not necessarily found on the hides and intestinal contents. The inconsistent occurrence of the diverse Salmonella serovars on hides, carcasses, and intestinal contents implies that in addition to carriage on hides and in intestinal contents, other external factors also play an important role regarding carcass contamination. The 92 Salmonella were serotyped and tested for susceptibility towards the following antimicrobials: ampicillin, cefotaxime, enrofloxacin, kanamycin, and oxytetracycline using the disk diffusion method. Most Salmonella (n = 66; 71.7% isolates were resistant to at least one antimicrobial with highest resistance observed towards oxytetracycline (51.90%, which highlights the need for strict hygiene during slaughter and prudent antimicrobial use during animal production. In conclusion, cattle slaughtered in South African rural abattoirs harbour diverse Salmonella serovars that are resistant to antimicrobials, which could be a public health risk. The findings should assist policymakers with improving

  20. Participatory eHealth development to support nurses in antimicrobial stewardship

    NARCIS (Netherlands)

    Wentzel, Jobke; Velsen, van Lex; Limburg, van Maarten; Jong, de Nienke; Karreman, Joyce; Hendrix, Ron; Gemert-Pijnen, van Julia Elisabeth Wilhelmina Cornelia

    2014-01-01

    Background Antimicrobial resistance poses a threat to patient safety worldwide. To stop antimicrobial resistance, Antimicrobial Stewardship Programs (ASPs; programs for optimizing antimicrobial use), need to be implemented. Within these programs, nurses are important actors, as they put antimicrobia

  1. The In Vitro Antimicrobial Effects of Lavandula angustifolia Essential Oil in Combination with Conventional Antimicrobial Agents

    Directory of Open Access Journals (Sweden)

    Stephanie de Rapper

    2016-01-01

    Full Text Available The paper focuses on the in vitro antimicrobial activity of Lavandula angustifolia Mill. (lavender essential oil in combination with four commercial antimicrobial agents. Stock solutions of chloramphenicol, ciprofloxacin, nystatin, and fusidic acid were tested in combination with L. angustifolia essential oil. The antimicrobial activities of the combinations were investigated against the Gram-positive bacterial strain Staphylococcus aureus (ATCC 6538 and Gram-negative Pseudomonas aeruginosa (ATCC 27858 and Candida albicans (ATCC 10231 was selected to represent the yeasts. The antimicrobial effect was performed using the minimum inhibitory concentration (MIC microdilution assay. Isobolograms were constructed for varying ratios. The most prominent interaction was noted when L. angustifolia essential oil was combined with chloramphenicol and tested against the pathogen P. aeruginosa (ΣFIC of 0.29. Lavendula angustifolia essential oil was shown in most cases to interact synergistically with conventional antimicrobials when combined in ratios where higher volumes of L. angustifolia essential oil were incorporated into the combination.

  2. Impact of medicated feed along with clay mineral supplementation on Escherichia coli resistance to antimicrobial agents in pigs after weaning in field conditions.

    Science.gov (United States)

    Jahanbakhsh, Seyedehameneh; Kabore, Kiswendsida Paul; Fravalo, Philippe; Letellier, Ann; Fairbrother, John Morris

    2015-10-01

    The aim of this study was to examine changes in antimicrobial resistance (AMR) phenotype and virulence and AMR gene profiles in Escherichia coli from pigs receiving in-feed antimicrobial medication following weaning and the effect of feed supplementation with a clay mineral, clinoptilolite, on this dynamic. Eighty E. coli strains isolated from fecal samples of pigs receiving a diet containing chlortetracycline and penicillin, with or without 2% clinoptilolite, were examined for antimicrobial resistance to 15 antimicrobial agents. Overall, an increased resistance to 10 antimicrobials was observed with time. Supplementation with clinoptilolite was associated with an early increase but later decrease in blaCMY-2, in isolates, as shown by DNA probe. Concurrently, a later increase in the frequency of blaCMY-2 and the virulence genes iucD and tsh was observed in the control pig isolates, being significantly greater than in the supplemented pigs at day 28. Our results suggest that, in the long term, supplementation with clinoptilolite could decrease the prevalence of E. coli carrying certain antimicrobial resistance and virulence genes.

  3. 住院患者产CTX-M型ESBLs和KPC的大肠埃希菌感染分布与耐药基因分析%Distribution and antimicrobial resistance genes of CTX-M extended-spec-trum β-lactamase-and Klebsiella pneumoniae carbapenemases-producing Escherichia coli isolated from patients with infection

    Institute of Scientific and Technical Information of China (English)

    蒋伟; 王思淼; 金鑫; 李佳佳

    2016-01-01

    Objective To investigate clinical distribution and antimicrobial resistance genes of CTX-M extended-spectrumβ-lactamases (ESBLs)- and Klebsiella pneumoniae carbapenemases (KPCs)-producing Escherichia coli (E.coli)isolated from patients with infection.Methods Multidrug-resistant E.coli (MDR-E.coli)isolated from clinical specimens in a hospital in 2011 -2012 were collected,minimal inhibitory concentrations (MICs)were detec-ted by micro-broth dilution method;ESBLs and KPC genes were amplified by polymerase chain reaction (PCR), CTX-M and KPC genotypes,as well as multilocus sequence types (MLST)were identified.Results Of 48 MDR-E. coli,45(93.75%)only produced ESBLs,44(91 .67%)carried bla CTX-M gene,20(41 .67%)of which were bla CTX-M-1 gene and 32(66.67%)were bla CTX-M-9 gene,8 (16.67%)carried both genes.The following subtypes were identified through gene sequencing:CTX-M-14(65.91 %,29/44),CTX-M-55(31 .82%,14/44),CTX-M-15(11 .36%,5/44), CTX-M-3(2.27%,1/44),CTX-M-24(2.27%,1/44),and CTX-M-65(2.27%,1/44).The detection rates of CTX-M-14+CTX-M-55,CTX-M-14+CTX-M-15,and CTX-M-55+CTX-M-65 were 11 .36% (5/44),4.55%(2/44), and 2.27%(1/44)respectively.PCR showed that 2 (4.17%)ESBLs +KPC-producing strains carried bla KPC and bla CTX-M genes,sequencing analysis showed that 1 was CTX-M-14 +KPC-2,and the other was CTX-M-3 +KPC-2.ST 131 (53.66%)was the main type of MLST,ST648,ST405,ST167,and ST1193 were also detected. Conclusion CTX-M-14,CTX-M-55 and CTX-M-15 are the most common genotypes of ESBLs-producing E.coli isolates,different subtypes exists,ST131 is the predominant MLST,KPC-2-producing isolate of E.coli has been detected.%目的:了解住院患者产 CTX-M 型超广谱β-内酰胺酶(ESBLs)和碳青霉烯酶(KPC)大肠埃希菌感染的临床分布与耐药情况。方法收集某院2011—2012年临床送检标本分离的多重耐药大肠埃希菌,采用微量肉汤稀释法检测抗菌药物最低抑菌浓度(MIC);聚合酶链反应(PCR)扩增 ESBLs

  4. All-trans retinoic acid-triggered antimicrobial activity against Mycobacterium tuberculosis is dependent on NPC2.

    Science.gov (United States)

    Wheelwright, Matthew; Kim, Elliot W; Inkeles, Megan S; De Leon, Avelino; Pellegrini, Matteo; Krutzik, Stephan R; Liu, Philip T

    2014-03-01

    A role for vitamin A in host defense against Mycobacterium tuberculosis has been suggested through epidemiological and in vitro studies; however, the mechanism is unclear. In this study, we demonstrate that vitamin A-triggered antimicrobial activity against M. tuberculosis requires expression of NPC2. Comparison of monocytes stimulated with all-trans retinoic acid (ATRA) or 1,25-dihydroxyvitamin D3 (1,25D3), the biologically active forms of vitamin A and vitamin D, respectively, indicates that ATRA and 1,25D3 induce mechanistically distinct antimicrobial activities. Stimulation of primary human monocytes with ATRA did not result in expression of the antimicrobial peptide cathelicidin, which is required for 1,25D3 antimicrobial activity. In contrast, ATRA triggered a reduction in the total cellular cholesterol concentration, whereas 1,25D3 did not. Blocking ATRA-induced cellular cholesterol reduction inhibits antimicrobial activity as well. Bioinformatic analysis of ATRA- and 1,25D3-induced gene profiles suggests that NPC2 is a key gene in ATRA-induced cholesterol regulation. Knockdown experiments demonstrate that ATRA-mediated decrease in total cellular cholesterol content and increase in lysosomal acidification are both dependent upon expression of NPC2. Expression of NPC2 was lower in caseous tuberculosis granulomas and M. tuberculosis-infected monocytes compared with normal lung and uninfected cells, respectively. Loss of NPC2 expression ablated ATRA-induced antimicrobial activity. Taken together, these results suggest that the vitamin A-mediated antimicrobial mechanism against M. tuberculosis requires NPC2-dependent expression and function, indicating a key role for cellular cholesterol regulation in the innate immune response.

  5. Use of antimicrobial agents during supportive periodontal therapy.

    Science.gov (United States)

    Venezia, E; Shapira, L

    2003-01-01

    Individual susceptibility to periodontal breakdown involves an interplay of genes, periodontal pathogens and other modulating factors. Anti-infective treatment, which includes oral hygiene measures, mechanical debridement, pharmacologic intervention and surgery, has been shown to be effective in arresting the progression of periodontal disease. Nevertheless, due to the chronic nature of the disease, susceptible individuals who are not maintained in a supervised recall program subsequent to the active treatment phase, show signs of recurrent destruction. Supportive periodontal therapy (SPT) is an integral part of periodontal treatment for patients with history of periodontitis, and is needed to prevent recurrence of disease in susceptible individuals. To prevent re-infection with periodontal pathogens, SPT includes elimination of dental plaque and bacteria from the oral cavity, thereby preventing the recurrence of pathogens into the gingival area. For individuals at risk of developing periodontitis, SPT should combine self-performed and professional anti-infective therapy, using mechanical and pharmacological means. The existing evidence suggests that the adjunctive use of antimicrobial pharmacologic therapy during SPT may enhance the results of mechanical debridement. The use of antimicrobials varies between patients, and is dependent on risk assessment and longitudinal monitoring of the clinical status of the periodontium.

  6. Antimicrobial Susceptibilities, Phage Types, and Molecular Characterization of Salmonella enterica Serovar Enteritidis from Chickens and Chicken Meat in Turkey

    DEFF Research Database (Denmark)

    Kalender, H.; Sen, S.; Hasman, Henrik

    2009-01-01

    Thirty-eight Salmonella Enteritidis isolates from chickens and chicken meat in Turkey were examined for antimicrobial susceptibility, XbaI pulsed-field gel electrophoresis (PFGE) patterns, phage types, plasmid profiles, and resistance genes. Seven different PFGE patterns were observed...

  7. Draft Genome Sequence of Pseudomonas sp. Strain In5 Isolated from a Greenlandic Disease Suppressive Soil with Potent Antimicrobial Activity

    DEFF Research Database (Denmark)

    Hennessy, Rosanna C.; Glaring, Mikkel Andreas; Frydenlund Michelsen, Charlotte;

    2015-01-01

    Pseudomonas sp. In5 is an isolate of disease suppressive soil with potent activity against pathogens. Its antifungal activity has been linked to a gene cluster encoding nonribosomal peptide synthetases producing the peptides nunamycin and nunapeptin. The genome sequence will provide insight...... into the genetics behind the antimicrobial activity of this strain....

  8. Molecular Characterization and Antimicrobial Susceptibility Testing of Escherichia coli Isolates from Patients with Urinary Tract Infections in 20 Chinese Hospitals

    DEFF Research Database (Denmark)

    Cao, Xiaoli; Cavaco, Lina; Lv, Yuan

    2011-01-01

    A total of 222 urinary Escherichia coli isolates from 20 tertiary hospitals in 15 different provinces and 4 municipalities in mainland China were characterized by antimicrobial susceptibility, phylogrouping, and the presence of plasmid-mediated quinolone resistance genes. A subset of 138 suspecte...

  9. Susceptibility of Pediococcus isolates to antimicrobial compounds in relation to hop-resistance and beer-spoilage

    Science.gov (United States)

    2009-01-01

    Background Though important in the context of food microbiology and as potential pathogens in immuno-compromised humans, bacterial isolates belonging to the genus Pediococcus are best known for their association with contamination of ethanol fermentation processes (beer, wine, or fuel ethanol). Use of antimicrobial compounds (e.g., hop-compounds, Penicillin) by some industries to combat Pediococcus contaminants is long-standing, yet knowledge about the resistance of pediococci to antimicrobial agents is minimal. Here we examined Pediococcus isolates to determine whether antibiotic resistance is associated with resistance to hops, presence of genes known to correlate with beer spoilage, or with ability to grow in beer. Results Lactic acid bacteria susceptibility test broth medium (LSM) used in combination with commercially available GPN3F antimicrobial susceptibility plates was an effective method for assessing antimicrobial susceptibility of Pediococcus isolates. We report the finding of Vancomycin-susceptible Pediococcus isolates from four species. Interestingly, we found that hop-resistant, beer-spoilage, and beer-spoilage gene-harbouring isolates had a tendency to be more susceptible, rather than more resistant, to antimicrobial compounds. Conclusion Our findings indicate that the mechanisms involved in conferring hop-resistance or ability to spoil beer by Pediococcus isolates are not associated with resistance to antibiotics commonly used for treatment of human infections. Also, Vancomycin-resistance was found to be isolate-specific and not intrinsic to the genus as previously believed. PMID:19735560

  10. Susceptibility of Pediococcus isolates to antimicrobial compounds in relation to hop-resistance and beer-spoilage

    Directory of Open Access Journals (Sweden)

    Ziola Barry

    2009-09-01

    Full Text Available Abstract Background Though important in the context of food microbiology and as potential pathogens in immuno-compromised humans, bacterial isolates belonging to the genus Pediococcus are best known for their association with contamination of ethanol fermentation processes (beer, wine, or fuel ethanol. Use of antimicrobial compounds (e.g., hop-compounds, Penicillin by some industries to combat Pediococcus contaminants is long-standing, yet knowledge about the resistance of pediococci to antimicrobial agents is minimal. Here we examined Pediococcus isolates to determine whether antibiotic resistance is associated with resistance to hops, presence of genes known to correlate with beer spoilage, or with ability to grow in beer. Results Lactic acid bacteria susceptibility test broth medium (LSM used in combination with commercially available GPN3F antimicrobial susceptibility plates was an effective method for assessing antimicrobial susceptibility of Pediococcus isolates. We report the finding of Vancomycin-susceptible Pediococcus isolates from four species. Interestingly, we found that hop-resistant, beer-spoilage, and beer-spoilage gene-harbouring isolates had a tendency to be more susceptible, rather than more resistant, to antimicrobial compounds. Conclusion Our findings indicate that the mechanisms involved in conferring hop-resistance or ability to spoil beer by Pediococcus isolates are not associated with resistance to antibiotics commonly used for treatment of human infections. Also, Vancomycin-resistance was found to be isolate-specific and not intrinsic to the genus as previously believed.

  11. Effects of Menthol Supplementation in Feedlot Cattle Diets on the Fecal Prevalence of Antimicrobial-Resistant Escherichia coli

    Science.gov (United States)

    Aperce, C. C.; Amachawadi, R.; Van Bibber-Krueger, C. L.; Nagaraja, T. G.; Scott, H. M.; Vinasco-Torre, J.; Drouillard, J. S.

    2016-01-01

    The pool of antimicrobial resistance determinants in the environment and in the gut flora of cattle is a serious public health concern. In addition to being a source of human exposure, these bacteria can transfer antibiotic resistance determinants to pathogenic bacteria and endanger the future of antimicrobial therapy. The occurrence of antimicrobial resistance genes on mobile genetic elements, such as plasmids, facilitates spread of resistance. Recent work has shown in vitro anti-plasmid activity of menthol, a plant-based compound with the potential to be used as a feed additive to beneficially alter ruminal fermentation. The present study aimed to determine if menthol supplementation in diets of feedlot cattle decreases the prevalence of multidrug-resistant bacteria in feces. Menthol was included in diets of steers at 0.3% of diet dry matter. Fecal samples were collected weekly for 4 weeks and analyzed for total coliforms counts, antimicrobial susceptibilities, and the prevalence of tet genes in E. coli isolates. Results revealed no effect of menthol supplementation on total coliforms counts or prevalence of E. coli resistant to amoxicillin, ampicillin, azithromycin, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfisoxazole, and sulfamethoxazole; however, 30 days of menthol addition to steer diets increased the prevalence of tetracycline-resistant E. coli (P menthol exerts its effects remains unclear, results of our study suggest that menthol may have an impact on antimicrobial resistance in gut bacteria. PMID:28030622

  12. Antimicrobial resistance in equine faecal Escherichia coli isolates from North West England

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    Williams Nicola J

    2010-04-01

    Full Text Available Abstract Background Escherichia coli isolates of equine faecal origin were investigated for antibiotic resistance, resistance genes and their ability to perform horizontal transfer. Methods In total, 264 faecal samples were collected from 138 horses in hospital and community livery premises in northwest England, yielding 296 resistant E. coli isolates. Isolates were tested for susceptibility to antimicrobial drugs by disc diffusion and agar dilution methods in order to determine minimum inhibitory concentrations (MIC. PCR amplification was used to detect genes conferring resistance to: ampicillin (TEM and SHV beta-lactamase, chloramphenicol (catI, catII, catIII and cml, tetracycline (tetA, tetB, tetC, tetD, tet E and tetG, and trimethoprim (dfrA1, dfrA9, dfrA12, dfrA13, dfr7, and dfr17. Results The proportion of antibiotic resistant isolates, and multidrug resistant isolates (MDR was significantly higher in hospital samples compared to livery samples (MDR: 48% of hospital isolates; 12% of livery isolates, p dfr, TEM beta-lactamase, tet and cat, conferring resistance to trimethoprim, ampicillin, tetracycline and chloramphenicol, respectively. Within each antimicrobial resistance group, these genes occurred at frequencies of 93% (260/279, 91%, 86.8% and 73.5%, respectively; with 115/296 (38.8% found to be MDR isolates. Conjugation experiments were performed on selected isolates and MDR phenotypes were readily transferred. Conclusions Our findings demonstrate that E. coli of equine faecal origin are commonly resistant to antibiotics used in human and veterinary medicine. Furthermore, our results suggest that most antibiotic resistance observed in equine E. coli is encoded by well-known and well-characterized resistant genes common to E. coli from man and domestic animals. These data support the ongoing concern about antimicrobial resistance, MDR, antimicrobial use in veterinary medicine and the zoonotic risk that horses could potentially pose to

  13. Antimicrobial Activity of Carbon-Based Nanoparticles

    Directory of Open Access Journals (Sweden)

    Solmaz Maleki Dizaj

    2015-03-01

    Full Text Available Due to the vast and inappropriate use of the antibiotics, microorganisms have begun to develop resistance to the commonly used antimicrobial agents. So therefore, development of the new and effective antimicrobial agents seems to be necessary. According to some recent reports, carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs (especially single-walled carbon nanotubes (SWCNTs and graphene oxide (GO nanoparticles show potent antimicrobial properties. In present review, we have briefly summarized the antimicrobial activity of carbon-based nanoparticles together with their mechanism of action. Reviewed literature show that the size of carbon nanoparticles plays an important role in the inactivation of the microorganisms. As major mechanism, direct contact of microorganisms with carbon nanostructures seriously affects their cellular membrane integrity, metabolic processes and morphology. The antimicrobial activity of carbon-based nanostructures may interestingly be investigated in the near future owing to their high surface/volume ratio, large inner volume and other unique chemical and physical properties. In addition, application of functionalized carbon nanomaterials as carriers for the ordinary antibiotics possibly will decrease the associated resistance, enhance their bioavailability and provide their targeted delivery.

  14. Evaluation of antimicrobial properties of cork.

    Science.gov (United States)

    Gonçalves, Filipa; Correia, Patrícia; Silva, Susana P; Almeida-Aguiar, Cristina

    2016-02-01

    Cork presents a range of diverse and versatile properties making this material suitable for several and extremely diverse industrial applications. Despite the wide uses of cork, its antimicrobial properties and potential applications have deserved little attention from industry and the scientific community. Thus, the main purpose of this work was the evaluation of the antibacterial properties of cork, by comparison with commercially available antimicrobial materials (Ethylene-Vinyl Acetate copolymer and a currently used antimicrobial commercial additive (ACA)), following the previous development and optimization of a method for such antimicrobial assay. The AATCC 100-2004 standard method, a quantitative procedure developed for the assessment of antimicrobial properties in textile materials, was used as reference and optimized to assess cork antibacterial activity. Cork displayed high antibacterial activity against Staphylococcus aureus, with a bacterial reduction of almost 100% (96.93%) after 90 minutes of incubation, similar to the one obtained with ACA. A more reduced but time-constant antibacterial action was observed against Escherichia coli (36% reduction of the initial number of bacterial colonies). To complement this study, antibacterial activity was further evaluated for a water extract of cork and an MIC of 6 mg mL(-1) was obtained against the reference strain S. aureus.

  15. Protease Inhibitors from Plants with Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Yoonkyung Park

    2009-06-01

    Full Text Available Antimicrobial proteins (peptides are known to play important roles in the innate host defense mechanisms of most living organisms, including plants, insects, amphibians and mammals. They are also known to possess potent antibiotic activity against bacteria, fungi, and even certain viruses. Recently, the rapid emergence of microbial pathogens that are resistant to currently available antibiotics has triggered considerable interest in the isolation and investigation of the mode of action of antimicrobial proteins (peptides. Plants produce a variety of proteins (peptides that are involved in the defense against pathogens and invading organisms, including ribosome-inactivating proteins, lectins, protease inhibitors and antifungal peptides (proteins. Specially, the protease inhibitors can inhibit aspartic, serine and cysteine proteinases. Increased levels of trypsin and chymotrypsin inhibitors correlated with the plants resistance to the pathogen. Usually, the purification of antimicrobial proteins (peptides with protease inhibitor activity was accomplished by salt-extraction, ultrafiltration and C18 reverse phase chromatography, successfully. We discuss the relation between antimicrobial and anti-protease activity in this review. Protease inhibitors from plants potently inhibited the growth of a variety of pathogenic bacterial and fungal strains and are therefore excellent candidates for use as the lead compounds for the development of novel antimicrobial agents.

  16. Antimicrobial cyclic peptides for plant disease control.

    Science.gov (United States)

    Lee, Dong Wan; Kim, Beom Seok

    2015-03-01

    Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources.

  17. Antimicrobial Cyclic Peptides for Plant Disease Control

    Directory of Open Access Journals (Sweden)

    Dong Wan Lee

    2015-03-01

    Full Text Available Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources.

  18. 原料乳和临床乳房炎金黄色葡萄球菌毒力基因检测及药敏分析%Characterization of toxin genes and antimicrobial susceptibility of Staphylococcus aureus isolated from raw milk and milk of clinical mastitis

    Institute of Scientific and Technical Information of China (English)

    张静; 于三科; 王新; 孙全才

    2012-01-01

    乳房炎加以重视。%A total of 101 Staphylococcus aureus isolates from raw milk(44 isolates) and milk of clinical mastitis(57 isolates) were tested,for the prevalence of nine enterotoxin and four other exotoxin genes by polymerase chain reaction and antimicrobial susceptibility testing by the agar dilution method.It shows that in the 44 strains of S.aureus from raw milk,84.09% were positive for one or more toxin genes,84.09% isolates harbored PVL gene,52.27% isolates harbored one or more SE genes,and sea(56.82%) was the most common pattern,mecA,ETs,TSST-1 sei and sej genes were not detected.Resistance was most frequently observed to trimethoprim(100%),followed by cefoxitin(86.36%),chloramphenicol(11.36%),erythromycin(4.55%),oxacillin(2.27%),cefoperazone(2.27%) and gentamicin(6.82%).All S.aureus isolates from raw milk were susceptible to amikacin,ciprofloxacin and vancomycin.Of the 57 strains of S.aureus from milk of clinical mastitis,78.95% were positive for one or more toxin genes,28.07% isolates harbored PVL gene,77.19% isolates harbored one or more SE genes,and sea(47.37%) was the most common pattern,10.53% mecA gene was detected,ETs,TSST-1 and seh genes were not detected.Resistance was most frequently observed to erythromycin(100%),followed by trimethoprim(71.93%),chloramphenicol(28.07%),gentamicin(26.07%),ciprofloxacin(24.56%),cefoxitin(19.30%) and oxacillin(7.02%).All isolates of S.aureus from milk of clinical mastitis were susceptible to amikacin,cefoperazone,vancomycin and tetracycline.Many S.aureus isolates from raw milk and milk of clinical mastitis contained different multiple resistance and various toxin genes,MRSA was only isolated from cows with clinical mastitis.Our results may provide useful information for assessment of the possible risk posed to milk products.

  19. Bioprospecting Red Sea Coastal Ecosystems for Culturable Microorganisms and Their Antimicrobial Potential

    KAUST Repository

    Al Amoudi, Soha

    2016-09-10

    Microorganisms that inhabit unchartered unique soil such as in the highly saline and hot Red Sea lagoons on the Saudi Arabian coastline, represent untapped sources of potentially new bioactive compounds. In this study, a culture-dependent approach was applied to three types of sediments: mangrove mud (MN), microbial mat (MM), and barren soil (BS), collected from Rabigh harbor lagoon (RHL) and Al-Kharrar lagoon (AKL). The isolated bacteria were evaluated for their potential to produce bioactive compounds. The phylogenetic characterization of 251 bacterial isolates based on the 16S rRNA gene sequencing, supported their assignment to five different phyla: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Planctomycetes. Fifteen putative novel species were identified based on a 16S rRNA gene sequence similarity to other strain sequences in the NCBI database, being ≤98%. We demonstrate that 49 of the 251 isolates exhibit the potential to produce antimicrobial compounds. Additionally, at least one type of biosynthetic gene sequence, responsible for the synthesis of secondary metabolites, was recovered from 25 of the 49 isolates. Moreover, 10 of the isolates had a growth inhibition effect towards Staphylococcus aureus, Salmonella typhimurium and Pseudomonas syringae. We report the previously unknown antimicrobial activity of B. borstelensis, P. dendritiformis and M. salipaludis against all three indicator pathogens. Our study demonstrates the evidence of diverse cultured microbes associated with the Red Sea harbor/lagoon environments and their potential to produce antimicrobial compounds.

  20. Bioprospecting Red Sea Coastal Ecosystems for Culturable Microorganisms and Their Antimicrobial Potential.

    Science.gov (United States)

    Al-Amoudi, Soha; Essack, Magbubah; Simões, Marta F; Bougouffa, Salim; Soloviev, Irina; Archer, John A C; Lafi, Feras F; Bajic, Vladimir B

    2016-09-10

    Microorganisms that inhabit unchartered unique soil such as in the highly saline and hot Red Sea lagoons on the Saudi Arabian coastline, represent untapped sources of potentially new bioactive compounds. In this study, a culture-dependent approach was applied to three types of sediments: mangrove mud (MN), microbial mat (MM), and barren soil (BS), collected from Rabigh harbor lagoon (RHL) and Al-Kharrar lagoon (AKL). The isolated bacteria were evaluated for their potential to produce bioactive compounds. The phylogenetic characterization of 251 bacterial isolates based on the 16S rRNA gene sequencing, supported their assignment to five different phyla: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Planctomycetes. Fifteen putative novel species were identified based on a 16S rRNA gene sequence similarity to other strain sequences in the NCBI database, being ≤98%. We demonstrate that 49 of the 251 isolates exhibit the potential to produce antimicrobial compounds. Additionally, at least one type of biosynthetic gene sequence, responsible for the synthesis of secondary metabolites, was recovered from 25 of the 49 isolates. Moreover, 10 of the isolates had a growth inhibition effect towards Staphylococcus aureus, Salmonella typhimurium and Pseudomonas syringae. We report the previously unknown antimicrobial activity of B. borstelensis, P. dendritiformis and M. salipaludis against all three indicator pathogens. Our study demonstrates the evidence of diverse cultured microbes associated with the Red Sea harbor/lagoon environments and their potential to produce antimicrobial compounds.

  1. Bioprospecting Red Sea Coastal Ecosystems for Culturable Microorganisms and Their Antimicrobial Potential

    Directory of Open Access Journals (Sweden)

    Soha Al-Amoudi

    2016-09-01

    Full Text Available Microorganisms that inhabit unchartered unique soil such as in the highly saline and hot Red Sea lagoons on the Saudi Arabian coastline, represent untapped sources of potentially new bioactive compounds. In this study, a culture-dependent approach was applied to three types of sediments: mangrove mud (MN, microbial mat (MM, and barren soil (BS, collected from Rabigh harbor lagoon (RHL and Al-Kharrar lagoon (AKL. The isolated bacteria were evaluated for their potential to produce bioactive compounds. The phylogenetic characterization of 251 bacterial isolates based on the 16S rRNA gene sequencing, supported their assignment to five different phyla: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Planctomycetes. Fifteen putative novel species were identified based on a 16S rRNA gene sequence similarity to other strain sequences in the NCBI database, being ≤98%. We demonstrate that 49 of the 251 isolates exhibit the potential to produce antimicrobial compounds. Additionally, at least one type of biosynthetic gene sequence, responsible for the synthesis of secondary metabolites, was recovered from 25 of the 49 isolates. Moreover, 10 of the isolates had a growth inhibition effect towards Staphylococcus aureus, Salmonella typhimurium and Pseudomonas syringae. We report the previously unknown antimicrobial activity of B. borstelensis, P. dendritiformis and M. salipaludis against all three indicator pathogens. Our study demonstrates the evidence of diverse cultured microbes associated with the Red Sea harbor/lagoon environments and their potential to produce antimicrobial compounds.

  2. Bioprospecting Red Sea Coastal Ecosystems for Culturable Microorganisms and Their Antimicrobial Potential

    Science.gov (United States)

    Al-Amoudi, Soha; Essack, Magbubah; Simões, Marta F.; Bougouffa, Salim; Soloviev, Irina; Archer, John A. C.; Lafi, Feras F.; Bajic, Vladimir B.

    2016-01-01

    Microorganisms that inhabit unchartered unique soil such as in the highly saline and hot Red Sea lagoons on the Saudi Arabian coastline, represent untapped sources of potentially new bioactive compounds. In this study, a culture-dependent approach was applied to three types of sediments: mangrove mud (MN), microbial mat (MM), and barren soil (BS), collected from Rabigh harbor lagoon (RHL) and Al-Kharrar lagoon (AKL). The isolated bacteria were evaluated for their potential to produce bioactive compounds. The phylogenetic characterization of 251 bacterial isolates based on the 16S rRNA gene sequencing, supported their assignment to five different phyla: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Planctomycetes. Fifteen putative novel species were identified based on a 16S rRNA gene sequence similarity to other strain sequences in the NCBI database, being ≤98%. We demonstrate that 49 of the 251 isolates exhibit the potential to produce antimicrobial compounds. Additionally, at least one type of biosynthetic gene sequence, responsible for the synthesis of secondary metabolites, was recovered from 25 of the 49 isolates. Moreover, 10 of the isolates had a growth inhibition effect towards Staphylococcus aureus, Salmonella typhimurium and Pseudomonas syringae. We report the previously unknown antimicrobial activity of B. borstelensis, P. dendritiformis and M. salipaludis against all three indicator pathogens. Our study demonstrates the evidence of diverse cultured microbes associated with the Red Sea harbor/lagoon environments and their potential to produce antimicrobial compounds. PMID:27626430

  3. Actinobacterial diversity in limestone deposit sites in Hundung, Manipur (India and their antimicrobial activities

    Directory of Open Access Journals (Sweden)

    Salam eNimaichand

    2015-05-01

    Full Text Available Studies on actinobacterial diversity in limestone habitats are scarce. This paper reports profiling of actinobacteria isolated from Hundung limestone samples in Manipur, India using ARDRA as the molecular tool for preliminary classification. A total of 137 actinobacteria were clustered into 31 phylotypic groups based on the ARDRA pattern generated and representative of each group was subjected to 16S rRNA gene sequencing. Generic diversity of the limestone isolates consisted of Streptomyces (15 phylotypic groups, Micromonospora (4, Amycolatopsis (3, Arthrobacter (3, Kitasatospora (2, Janibacter (1, Nocardia (1, Pseudonocardia (1 and Rhodococcus (1. Considering the antimicrobial potential of these actinobacteria, 19 showed antimicrobial activities against at least one of the bacterial and candidal test pathogens, while 45 exhibit biocontrol activities against at least one of the rice fungal pathogens. Out of the 137 actinobacterial isolates, 118 were found to have at least one of the three biosynthetic gene clusters (PKS-I, PKS-II, NRPS. The results indicate that 86% of the strains isolated from Hundung limestone deposit sites possessed biosynthetic gene clusters of which 40% exhibited antimicrobial activities. It can, therefore, be concluded that limestone habitat is a promising source for search of novel secondary metabolites.

  4. Actinobacterial diversity in limestone deposit sites in Hundung, Manipur (India) and their antimicrobial activities.

    Science.gov (United States)

    Nimaichand, Salam; Devi, Asem Mipeshwaree; Tamreihao, K; Ningthoujam, Debananda S; Li, Wen-Jun

    2015-01-01

    Studies on actinobacterial diversity in limestone habitats are scarce. This paper reports profiling of actinobacteria isolated from Hundung limestone samples in Manipur, India using ARDRA as the molecular tool for preliminary classification. A total of 137 actinobacteria were clustered into 31 phylotypic groups based on the ARDRA pattern generated and representative of each group was subjected to 16S rRNA gene sequencing. Generic diversity of the limestone isolates consisted of Streptomyces (15 phylotypic groups), Micromonospora (4), Amycolatopsis (3), Arthrobacter (3), Kitasatospora (2), Janibacter (1), Nocardia (1), Pseudonocardia (1) and Rhodococcus (1). Considering the antimicrobial potential of these actinobacteria, 19 showed antimicrobial activities against at least one of the bacterial and candidal test pathogens, while 45 exhibit biocontrol activities against at least one of the rice fungal pathogens. Out of the 137 actinobacterial isolates, 118 were found to have at least one of the three biosynthetic gene clusters (PKS-I, PKS-II, NRPS). The results indicate that 86% of the strains isolated from Hundung limestone deposit sites possessed biosynthetic gene clusters of which 40% exhibited antimicrobial activities. It can, therefore, be concluded that limestone habitat is a promising source for search of novel secondary metabolites.

  5. From microbial gene essentiality to novel antimicrobial drug targets

    NARCIS (Netherlands)

    Mobegi, Fredrick M; van Hijum, Sacha Aft; Burghout, Peter; Bootsma, Hester J; de Vries, Stefan Pw; Jongh, Christa E van der Gaast-de; Simonetti, Elles; Langereis, Jeroen D; Hermans, Peter Wm; de Jonge, Marien I; Zomer, Aldert

    2014-01-01

    BACKGROUND: Bacterial respiratory tract infections, mainly caused by Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are among the leading causes of global mortality and morbidity. Increased resistance of these pathogens to existing antibiotics necessitates the search for

  6. Antimicrobial Testing Methods & Procedures Developed by EPA's Microbiology Laboratory

    Science.gov (United States)

    We develop antimicrobial testing methods and standard operating procedures to measure the effectiveness of hard surface disinfectants against a variety of microorganisms. Find methods and procedures for antimicrobial testing.

  7. [Antimicrobial properties of antiseptic composite with prolonged action].

    Science.gov (United States)

    Paliĭ, G K; Nazarchuk, A A; Paliĭ, D V; Nazarchuk, G G; Gonchar, O O; Sukhliak, V V; Trofimenko, Iu Iu; Zadereĭ, N V; Stukan, O K

    2013-01-01

    Antimicrobial properties of a composite based on decamethoxine and modified polysaccharides (carboxymethylamylum, oxyethyl-cellulose) were studied. The composite was shown to have high antimicrobial activity against grampositive and gramnegative bacteria under different conditions of the experiment.

  8. Measuring Appropriate Antimicrobial Use: Attempts at Opening the Black Box.

    Science.gov (United States)

    Spivak, Emily S; Cosgrove, Sara E; Srinivasan, Arjun

    2016-12-15

    Indiscriminate antimicrobial use has plagued medicine since antibiotics were first introduced into clinical practice >70 years ago. Infectious diseases physicians and public health officials have advocated for preservation of these life-saving drugs for many years. With rising burden of antimicrobial-resistant organisms and Clostridium difficile infections, halting unnecessary antimicrobial use has become one of the largest public health concerns of our time. Inappropriate antimicrobial use has been quantified in various settings using numerous definitions; however, no established reference standard exists. With mounting national efforts to improve antimicrobial use, a consensus definition and standard method of measuring appropriate antimicrobial use is imperative. We review existing literature on systematic approaches to define and measure appropriate antimicrobial use, and describe a collaborative effort at developing standardized audit tools for assessing the quality of antimicrobial prescribing.

  9. Insights into Animal and Plant Lectins with Antimicrobial Activities

    Directory of Open Access Journals (Sweden)

    Renata de Oliveira Dias

    2015-01-01

    Full Text Available Lectins are multivalent proteins with the ability to recognize and bind diverse carbohydrate structures. The glyco -binding and diverse molecular structures observed in these protein classes make them a large and heterogeneous group with a wide range of biological activities in microorganisms, animals and plants. Lectins from plants and animals are commonly used in direct defense against pathogens and in immune regulation. This review focuses on sources of animal and plant lectins, describing their functional classification and tridimensional structures, relating these properties with biotechnological purposes, including antimicrobial activities. In summary, this work focuses on structural-functional elucidation of diverse lectin groups, shedding some light on host-pathogen interactions; it also examines their emergence as biotechnological tools through gene manipulation and development of new drugs.

  10. Prevalence of Yersinia enterocolitica in antimicrobial-free and conventional antimicrobial use swine production.

    Science.gov (United States)

    Funk, Julie A; Abley, Melanie J; Bowman, Andrew S; Gebreyes, Wondwossen A; Morrow, William E Morgan; Tadesse, Daniel A

    2013-06-01

    Swine are the primary reservoir for foodborne illness associated with Yersinia enterocolitica. The use of antimicrobials in animal agriculture has been hypothesized as having a potential role in the increase in prevalence of zoonotic pathogens. The objective of this study was to compare the frequency of Y. enterocolitica fecal shedding in swine reared on farms with conventional antimicrobial use policies to farms that were antimicrobial free (ABF). Swine farms were selected from three regions in the United States. In each region, farms were categorized based on antimicrobial use policy. Fecal samples were collected from pigs on-farm within 48 h of harvest. The overall proportion of Y. enterocolitica and ail-harboring Y. enterocolitica-positive pigs was 10.9% and 4.0%, respectively. There were increased odds (odds ratio [OR] 6.8, 95% confidence interval [CI] 3.46-13.28) for a pig to be Y. enterocolitica positive if it was reared on an ABF farm as compared to a conventional farm. There was no significant association between farm antimicrobial use policy and isolation of an ail-harboring Y. enterocolitica from an individual pig (OR 1.8, 95% CI 0.90-3.61). The association of antimicrobial use policy with Y. enterocolitica shedding in feces should be interpreted cautiously, as antimicrobial use cannot be separated from other management factors (e.g., confinement or outdoor housing), which may be associated with risk of Y. enterocolitica in swine.

  11. Use and Misuse of Antimicrobial Drugs in Poultry and Livestock: Mechanisms of Antimicrobial Resistance

    Directory of Open Access Journals (Sweden)

    Toni Poole* and Cynthia Sheffield

    2013-07-01

    Full Text Available Food safety begins on the farm with management practices that contribute to an abundant, safe, and affordable food supply. To attain this goal antimicrobials have been used in all stages of food animal production in the United States and elsewhere around the world at one time or another. Among food–production animals antimicrobials are used for growth promotion, disease prophylaxis or disease treatment, and are generally administered to the entire flock or herd. Over many decades bacteria have become resistant to multiple antimicrobial classes in a cumulative manner. Bacteria exhibit a number of well characterized mechanisms of resistance to antimicrobials that include: 1 modification of the antimicrobial; 2 alteration of the drug target; 3 decreased access of drug to target; and 4 implementation of an alternative metabolic pathway not affected by the drug. The mechanisms of resistance are complex and depend on the type of bacterium involved (e.g. Gram–positive or Gram–negative and the class of drug. Some bacterial species have accumulated resistance to nearly all antimicrobial classes due to a combination of intrinsic and acquired processes. This has and will continue to lead to clinical failures of antimicrobial treatment in both human and animal medicine.

  12. Availability and estimates of veterinary antimicrobial use in British Columbia

    OpenAIRE

    2004-01-01

    The amount of antimicrobial use is a significant selection pressure that alters the frequency of antimicrobial resistance. This paper summarizes attempts to estimate the weight of antimicrobial purchases in British Columbia for use in animals. The data reported here do not capture all sources of veterinary antimicrobial use in British Columbia. This paper highlights how information deficits on veterinary drug use complicate the development of an evidence-based policy framework for combating a...

  13. Curbing the menace of antimicrobial resistance in developing countries

    OpenAIRE

    Sosa Anibal; Tapha-Sosseh Ndey; Nweneka Chidi

    2009-01-01

    Abstract Several reports suggest that antimicrobial resistance is an increasing global problem; but like most pandemics, the greatest toll is in the less developed countries. The dismally low rate of discovery of antimicrobials compared to the rate of development of antimicrobial resistance places humanity on a very dangerous precipice. Since antimicrobial resistance is part of an organism's natural survival instinct, total eradication might be unachievable; however, it can be reduced to a le...

  14. Recent Advances in Antimicrobial Polymers: A Mini-Review

    OpenAIRE

    Huang, Keng-Shiang; Yang, Chih-Hui; Huang, Shu-Ling; Chen, Cheng-You; Lu, Yuan-Yi; Lin, Yung-Sheng

    2016-01-01

    Human safety and well-being is threatened by microbes causing numerous infectious diseases resulting in a large number of deaths every year. Despite substantial progress in antimicrobial drugs, many infectious diseases remain difficult to treat. Antimicrobial polymers offer a promising antimicrobial strategy for fighting pathogens and have received considerable attention in both academic and industrial research. This mini-review presents the advances made in antimicrobial polymers since 2013....

  15. Effect of Fatty Acid Conjugation on Antimicrobial Peptide Activity

    Science.gov (United States)

    2004-12-01

    killing mechanism of antimicrobial peptides makes them an interesting alternative to traditional antibiotics, as target bacteria may be less able...C14-AKK and C16-AKK to within a 7% error are 220 and 16mM respectively. Since amphipathicity is requisite for antimicrobial action KAK is not...Schnaare, 2000: Antimicrobial evaluation of N-alkyl betaines and N-alkyl-N,N-dimethylamine oxides with variations in chain length. Antimicrobial Agents

  16. Antimicrobial resistance of Salmonella spp. isolated from food

    Science.gov (United States)

    Mąka, Łukasz; Popowska, Magdalena

    This review summarizes current data on resistance among Salmonella spp. isolates of food origin from countries in different regions of the world. The mechanisms of resistance to different groups of antimicrobial compounds are also considered. Among strains resistant to quinolones and/or fluoroquinolones the most prevalent mechanism is amino acid substitutions in quinolone resistance-determining region (QRDR) of genes gyrA, parC but mechanism of growing importance is plasmid-mediated quinolone resistance (PMQR) associated with genes qnrA, qnrB, qnrC, qnrD, qnrS but frequency of their detection is different. Resistance to sulfonamides is mostly associated with genes sul1 and sul2, while resistance to trimethoprim is associated with various variants of dhfr ( dfr) genes. Taking into account Salmonella spp. strains isolated from food, resistance to β-lactams is commonly associated with β-lactamases encoding by blaTEM genes. However strains ESBL and AmpC – positive are also detected. Resistance to aminoglicosides is commonly result of enzymatic inactivation. Three types of aminoglycoside modifying enzyme are: acetyltransferases (AAC), adenyltransferases (ANT) and phosphotransferases (APH). Resistance to tetracyclines among Salmonella spp. isolated from food is most commonly associated with active efflux. Among numerous genetic determinants encoding efflux pumps tetA, tetB, tetC, tetD, tetE and tetG are reported predominatingly. One of the most common mechanisms of resistance against chloramphenicol is its inactivation by chloramphenicol acetyltrasferases (CATs), but resistance to this compound can be also mediated by chloramphenicol efflux pumps encoded by the genes cmlA and floR. It is important to monitor resistance of Salmonella isolated from food, because the globalization of trade, leading to the long-distance

  17. Antimicrobial Resistance of Escherichia fergusonii Isolated from Broiler Chickens.

    Science.gov (United States)

    Simmons, Karen; Islam, M Rashedul; Rempel, Heidi; Block, Glenn; Topp, Edward; Diarra, Moussa S

    2016-06-01

    The objective of this study was to investigate the antibiotic resistance of Escherichia fergusonii isolated from commercial broiler chicken farms. A total of 245 isolates from cloacal and cecal samples of 28- to 36-day-old chickens were collected from 32 farms. Isolates were identified using PCR, and their susceptibility to 16 antibiotics was determined by disk diffusion assay. All isolates were susceptible to meropenem, amikacin, and ciprofloxacin. The most common resistances were against ampicillin (75.1%), streptomycin (62.9%), and tetracycline (57.1%). Of the 184 ampicillin-resistant isolates, 127 were investigated using a DNA microarray carrying 75 probes for antibiotic resistance genetic determinants. Of these 127 isolates, the β-lactamase blaCMY2, blaTEM, blaACT, blaSHV, and blaCTX-M-15 genes were detected in 120 (94.5%), 31 (24.4%), 8 (6.3%), 6 (4.7%), and 4 (3.2%) isolates, respectively. Other detected genes included those conferring resistance to aminoglycosides (aadA1, strA, strB), trimethoprims (dfrV, dfrA1), tetracyclines (tetA, tetB, tetC, tetE), and sulfonamides (sul1, sul2). Class 1 integron was found in 35 (27.6%) of the ampicillin-resistant isolates. However, our data showed that the tested E. fergusonii did not carry any carbapenemase blaOXA genes. Pulsed-field gel electrophoresis revealed that the selected ampicillin-resistant E. fergusonii isolates were genetically diverse. The present study indicates that the monitoring of antimicrobial-resistant bacteria should include enteric bacteria such as E. fergusonii, which could be a reservoir of antibiotic resistance genes. The detection of isolates harboring extended-spectrum β-lactamase genes, particularly blaCTX-M-15, in this work suggests that further investigations on the occurrence of such genes in broilers are warranted.

  18. Mechanisms of Antimicrobial Resistance in ESKAPE Pathogens

    Directory of Open Access Journals (Sweden)

    Sirijan Santajit

    2016-01-01

    Full Text Available The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species are the leading cause of nosocomial infections throughout the world. Most of them are multidrug resistant isolates, which is one of the greatest challenges in clinical practice. Multidrug resistance is amongst the top three threats to global public health and is usually caused by excessive drug usage or prescription, inappropriate use of antimicrobials, and substandard pharmaceuticals. Understanding the resistance mechanisms of these bacteria is crucial for the development of novel antimicrobial agents or other alternative tools to combat these public health challenges. Greater mechanistic understanding would also aid in the prediction of underlying or even unknown mechanisms of resistance, which could be applied to other emerging multidrug resistant pathogens. In this review, we summarize the known antimicrobial resistance mechanisms of ESKAPE pathogens.

  19. In vitro antimicrobial activity of olive leaves.

    Science.gov (United States)

    Markin, D; Duek, L; Berdicevsky, I

    2003-04-01

    We investigated the antimicrobial effect of olive leaves against bacteria and fungi. The microorganisms tested were inoculated in various concentrations of olive leaf water extract. Olive leaf 0.6% (w/v) water extract killed almost all bacteria tested, within 3 h. Dermatophytes were inhibited by 1.25% (w/v) plant extract following a 3-day exposure whereas Candida albicans was killed following a 24 h incubation in the presence of 15% (w/v) plant extract. Olive leaf extract fractions, obtained by dialysis, that showed antimicrobial activity consisted of particles smaller than 1000 molecular rate cutoffs. Scanning electron microscopic observations of C. albicans, exposed to 40% (w/v) olive leaf extract, showed invaginated and amorphous cells. Escherichia coli cells, subjected to a similar treatment but exposed to only 0.6% (w/v) olive leaf extract showed complete destruction. These findings suggest an antimicrobial potential for olive leaves.

  20. The Antimicrobial Activity of Porphyrin Attached Polymers

    Science.gov (United States)

    Thompson, Lesley

    2008-03-01

    We are interested in testing the antimicrobial activity of a porphyrin that is attached to a polymer. The porphyrin (5-(4-carboxyphenyl)-10,15,20-tris-(4-pryridyl)) was synthesized from methyl 4-formyl benzoate, 4-pyridinecarboxaldehyde, and pyrrole and attached to a copolymer of polystyrene/poly(vinyl benzyl chloride), which was synthesized by free radical polymerization. The antimicrobial activity of the polymer-attached porphyrin was then determined for gram-negative E. Coli grown to 0.80 OD. In this procedure, glass slides were coated with polymer-attached porphyrin via dip-coating, and the E. Coli bacteria were plated in Luria Broth media. The plates were subsequently exposed to light overnight before they were incubated as porphyrins act as photo-sensitizers when irradiated with light. The polymer-attached porphyrin did exhibit antimicrobial activity and parameters that affect its efficiency will be discussed.

  1. Real-Time Optical Antimicrobial Susceptibility Testing

    DEFF Research Database (Denmark)

    Fredborg, Marlene; Andersen, Klaus R; Jørgensen, Erik;

    2013-01-01

    Rapid antibiotic susceptibility testing is in highly demand in health-care fields as antimicrobial resistant bacterial strains emerge and spread. Here we describe an optical screening system (oCelloScope), which based on time-lapse imaging of 96 bacteria-antibiotic combinations at a time, introdu......Rapid antibiotic susceptibility testing is in highly demand in health-care fields as antimicrobial resistant bacterial strains emerge and spread. Here we describe an optical screening system (oCelloScope), which based on time-lapse imaging of 96 bacteria-antibiotic combinations at a time......, introduces real-time detection of bacterial growth and antimicrobial susceptibility, with imaging material to support the automatically generated graphs. Automated antibiotic susceptibility tests of a monoculture showed statistically significant antibiotic effect within 6 minutes and within 30 minutes...

  2. ANTIMICROBIAL ACTIVITY OF FICUS GLOMERATA LINN. BARK

    Directory of Open Access Journals (Sweden)

    Jagtap Supriya G.

    2012-05-01

    Full Text Available Ficus glomerata Linn. (Moraceae, commonly known as Ficus racemosa. A large deciduous tree distributed all over India and Ceylon, found throughout the year, grows in evergreen forest, moist localities, along the sides of ravines and banks of streams. Gular (Ficus glomerata Linn. is well known, commonly used plant in various disorders. It has been traditionally claimed to be useful in asthmatic condition, as an antitussive and anti-inflammatory. Successive soxhlet extractions of dried powdered bark were carried out using petroleum ether and methanol as a solvent. The antimicrobial activity of the extracts were tested in vitro against two different bacterial species Bacillus substilis and Escherichia coli by cup plate diffusion method were used in this investigation. The results of antimicrobial activity revealed that methanolic extract showed good activity as compared to petroleum ether extract. Methanolic extract is more potent towards gram - positive bacteria. The antimicrobial activities of the extracts were compared with standard antibiotics.

  3. Recent Developments in Antimicrobial Polymers: A Review

    Directory of Open Access Journals (Sweden)

    Madson R. E. Santos

    2016-07-01

    Full Text Available Antimicrobial polymers represent a very promising class of therapeutics with unique characteristics for fighting microbial infections. As the classic antibiotics exhibit an increasingly low capacity to effectively act on microorganisms, new solutions must be developed. The importance of this class of materials emerged from the uncontrolled use of antibiotics, which led to the advent of multidrug-resistant microbes, being nowadays one of the most serious public health problems. This review presents a critical discussion of the latest developments involving the use of different classes of antimicrobial polymers. The synthesis pathways used to afford macromolecules with antimicrobial properties, as well as the relationship between the structure and performance of these materials are discussed.

  4. Antimicrobial peptides in innate immune responses.

    Science.gov (United States)

    Sørensen, Ole E; Borregaard, Niels; Cole, Alexander M

    2008-01-01

    Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de novo synthesis or by proteolytic cleavage from antimicrobially inactive proproteins. Studies of human diseases and animal studies have given important clues to the in vivo role of AMPs. It is now evident that dysregulation of the generation of AMPs in innate immune responses plays a role in certain diseases like Crohn's disease and atopic dermatitis. AMPs are attractive candidates for development of novel antibiotics due to their in vivo activity profile and some peptides may serve as templates for further drug development.

  5. Isolation of an antimicrobial compound produced by bacteria associated with reef-building corals

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Raina

    2016-08-01

    Full Text Available Bacterial communities associated with healthy corals produce antimicrobial compounds that inhibit the colonization and growth of invasive microbes and potential pathogens. To date, however, bacteria-derived antimicrobial molecules have not been identified in reef-building corals. Here, we report the isolation of an antimicrobial compound produced by Pseudovibrio sp. P12, a common and abundant coral-associated bacterium. This strain was capable of metabolizing dimethylsulfoniopropionate (DMSP, a sulfur molecule produced in high concentrations by reef-building corals and playing a role in structuring their bacterial communities. Bioassay-guided fractionation coupled with nuclear magnetic resonance (NMR and mass spectrometry (MS, identified the antimicrobial as tropodithietic acid (TDA, a sulfur-containing compound likely derived from DMSP catabolism. TDA was produced in large quantities by Pseudovibrio sp., and prevented the growth of two previously identified coral pathogens, Vibrio coralliilyticus and V. owensii, at very low concentrations (0.5 μg/mL in agar diffusion assays. Genome sequencing of Pseudovibrio sp. P12 identified gene homologs likely involved in the metabolism of DMSP and production of TDA. These results provide additional evidence for the integral role of DMSP in structuring coral-associated bacterial communities and underline the potential of these DMSP-metabolizing microbes to contribute to coral disease prevention.

  6. Changes in antimicrobial susceptibility of native Enterococcus faecium in chickens fed virginiamycin.

    Science.gov (United States)

    McDermott, Patrick F; Cullen, Patti; Hubert, Susannah K; McDermott, Shawn D; Bartholomew, Mary; Simjee, Shabbir; Wagner, David D

    2005-09-01

    The extent of transfer of antimicrobial resistance from agricultural environments to humans is controversial. To assess the potential hazard posed by streptogramin use in food animals, this study evaluated the effect of virginiamycin exposure on antimicrobial resistance in Enterococcus faecium recovered from treated broilers. Four consecutive broiler feeding trials were conducted using animals raised on common litter. In the first three trials, one group of birds was fed virginiamycin continuously in feed at 20 g/ton, and a second group served as the nontreated control. In the fourth trial, antimicrobial-free feed was given to both groups. Fecal samples were cultured 1 day after chickens hatched and then at 1, 3, 5, and 7 weeks of age. Isolates from each time point were tested for susceptibility to a panel of different antimicrobials. Quinupristin/dalfopristin-resistant E. faecium appeared after 5 weeks of treatment in trial 1 and within 7 days of trials 2 to 4. Following removal of virginiamycin in trial 4, no resistant isolates were detected after 5 weeks. PCR failed to detect vat, vgb, or erm(B) in any of the streptogramin-resistant E. faecium isolates, whereas the msr(C) gene was detected in 97% of resistant isolates. In an experimental setting using broiler chickens, continuous virginiamycin exposure was required to maintain a stable streptogramin-resistant population of E. faecium in the animals. The bases of resistance could not be explained by known genetic determinants.

  7. Molecular Identification of Lactic Acid Bacteria Producing Antimicrobial Agents from Bakasang, An Indonesian Traditional Fermented Fish Product

    Directory of Open Access Journals (Sweden)

    Helen Joan Lawalata

    2015-11-01

    Full Text Available AbstractTwenty seven strains of lactic acid bacteria (LAB were isolated from bakasang, Indonesian traditional fermented fish product. In general, LAB have inhibitory activity againts pathogenic bacteria and spoilage bacteria. Screening for antimicrobia activity of isolates were performed with well-diffusion method. One isolate that was designed as Pediococcus BksC24 was the strongest against bacteria pathogenic and spoilage bacteria. This strain was further identified by 16S rRNA gen sequence comparison. Isolates LAB producing antimicrobial agents from bakasang were identified as Pediococcus acidilactici.Keywords : Bakasang, LAB, antimicrobial, phenotypic characteristics, 16S rRNA gene

  8. Antimicrobials in animal agriculture: parables and policy.

    Science.gov (United States)

    Scott, H M; Midgley, G; Loneragan, G H

    2015-04-01

    In addition to the scientific, economic, regulatory and other policy factors that impact on antimicrobial decision-making in different jurisdictions around the world, there exist ethical, social and cultural bases for the contemporary use of these products in animal agriculture. Thus, the use of the word 'parable' to describe the contemporary moral stories that help to guide ethical antimicrobial use practices and broader policy decisions in animal agriculture is appropriate. Several of these stories reflect difficult decisions that arise from conflicting moral imperatives (i.e. both towards animal welfare and towards human health). Understanding the factors that combine to define the past and present paradigms of antimicrobial usage is crucial to mapping a path forward. There exist barriers, as well as opportunities, for advancing scenarios for reducing antimicrobial usage under a variety of voluntary, regulatory and legal policy frameworks. Any new approaches will ideally be structured to extend the use of present-day antimicrobials into the future, to provide novel alternatives for regulating any newly introduced antimicrobial products so as to maximize their useful life span and to ensure the optimal use of these products in animal agriculture to protect not only the health of animals and the interests of animal health/agriculture stakeholders, but also the human health and the interests of the public at large. A full range of policy approaches, which span the realm from strictly enforced regulations and laws to voluntary guidelines and compliance, should be explored with respect to their risks and benefits in a variety of worldwide settings and in full consideration of a range of stakeholder values.

  9. 77 FR 44177 - Antimicrobial Animal Drug Sales and Distribution Reporting

    Science.gov (United States)

    2012-07-27

    ... addressing the judicious use of medically important antimicrobial drugs in food-producing animals (Ref. 2... information about the extent of antimicrobial drug use in food-producing animals. Specifically, the Agency is... HUMAN SERVICES Food and Drug Administration 21 CFR Part 514 Antimicrobial Animal Drug Sales...

  10. Antimicrobial potential of Glycyrrhiza glabra roots.

    Science.gov (United States)

    Gupta, Vivek K; Fatima, Atiya; Faridi, Uzma; Negi, Arvind S; Shanker, Karuna; Kumar, J K; Rahuja, Neha; Luqman, Suaib; Sisodia, Brijesh S; Saikia, Dharmendra; Darokar, M P; Khanuja, Suman P S

    2008-03-05

    The present study was aimed to investigate antimicrobial potential of Glycyrrhiza glabra roots. Antimycobacterial activity of Glycyrrhiza glabra was found at 500 microg/mL concentration. Bioactivity guided phytochemical analysis identified glabridin as potentially active against both Mycobacterium tuberculosis H(37)Ra and H(37)Rv strains at 29.16 microg/mL concentration. It exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria. Our results indicate potential use of licorice as antitubercular agent through systemic experiments and sophisticated anti-TB assay.

  11. Antimicrobial Action of Compounds from Marine Seaweed

    Directory of Open Access Journals (Sweden)

    María José Pérez

    2016-03-01

    Full Text Available Seaweed produces metabolites aiding in the protection against different environmental stresses. These compounds show antiviral, antiprotozoal, antifungal, and antibacterial properties. Macroalgae can be cultured in high volumes and would represent an attractive source of potential compounds useful for unconventional drugs able to control new diseases or multiresistant strains of pathogenic microorganisms. The substances isolated from green, brown and red algae showing potent antimicrobial activity belong to polysaccharides, fatty acids, phlorotannins, pigments, lectins, alkaloids, terpenoids and halogenated compounds. This review presents the major compounds found in macroalga showing antimicrobial activities and their most promising applications.

  12. Antimicrobial coatings — obtaining and characterization

    Indian Academy of Sciences (India)

    Cornelia Guran; Alexandra Pica; Denisa Ficai; Anton Ficai; Cezar Comanescu

    2013-04-01

    In this paper, we present inorganic–organic hybrid coatings with polymer matrix (water soluble) that contain silver nanoparticles (AgNPs). The structure and morphology of coating materials were determined by infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). Therefore, the antimicrobial activities and mechanisms of coatings for several pathogenic bacteria (Bacilius cereus and Staphylococcus aureus) were investigated. It was demonstrated that the obtained material with silver nanoparticles keep their antimicrobial effect even if they are subjected to several cycles of washing with water and detergent.

  13. Antimicrobial activity of Tridax procumbens