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Sample records for tomato bacterial pathogens

  1. Pseudomonas floridensis sp. nov., a bacterial pathogen isolated from tomato.

    Science.gov (United States)

    Timilsina, Sujan; Minsavage, Gerald V; Preston, James; Newberry, Eric A; Paret, Matthews L; Goss, Erica M; Jones, Jeffrey B; Vallad, Gary E

    2018-01-01

    An unusual fluorescent pseudomonad was isolated from tomato exhibiting leaf spot symptoms similar to bacterial speck. Strains were fluorescent, oxidase- and arginine-dihydrolase-negative, elicited a hypersensitive reaction on tobacco and produced a soft rot on potato slices. However, the strains produced an unusual yellow, mucoid growth on media containing 5 % sucrose that is not typical of levan. Based on multilocus sequence analysis using 16S rRNA, gap1, gltA, gyrB and rpoD, these strains formed a distinct phylogenetic group in the genus Pseudomonas and were most closely related to Pseudomonas viridiflava within the Pseudomonassyringae complex. Whole-genome comparisons, using average nucleotide identity based on blast, of representative strain GEV388 T and publicly available genomes representing the genus Pseudomonas revealed phylogroup 7 P. viridiflava strain UASW0038 and P. viridiflava type strain ICMP 2848 T as the closest relatives with 86.59 and 86.56 % nucleotide identity, respectively. In silico DNA-DNA hybridization using the genome-to-genome distance calculation method estimated 31.1 % DNA relatedness between GEV388 T and P. viridiflava ATCC 13223 T , strongly suggesting the strains are representatives of different species. These results together with Biolog GEN III tests, fatty acid methyl ester profiles and phylogenetic analysis using 16S rRNA and multiple housekeeping gene sequences demonstrated that this group represents a novel species member of the genus Pseudomonas. The name Pseudomonas floridensis sp. nov. is proposed with GEV388 T (=LMG 30013 T =ATCC TSD-90 T ) as the type strain.

  2. Root-associated bacterial endophytes from Ralstonia solanacearum resistant and susceptible tomato cultivars and their pathogen antagonistic effects

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    Reshmi eUpreti

    2015-04-01

    Full Text Available This study was undertaken to assess if the root-associated native bacterial endophytes in tomato have any bearing in governing the host resistance to the wilt pathogen Ralstonia solanacearum. Internal colonization of roots by bacterial endophytes was confirmed through confocal imaging after SYTO-9 staining. Endophytes were isolated from surface-sterilized roots of 4-week old seedlings of known wilt resistant (R tomato cultivar Arka Abha and susceptible (S cv. Arka Vikas on nutrient agar after plating the tissue homogenate. Arka Abha displayed more diversity with nine distinct organisms while Arka Vikas showed five species with two common organisms (Pseudomonas oleovorans and Agrobacterium tumefaciens. Screening for general indicators of biocontrol potential showed more isolates from Arka Abha positive for siderophore, HCN and antibiotic biosynthesis than from Arka Vikas. Direct challenge against the pathogen indicated strong antagonism by three Arka Abha isolates (P. oleovorans, Pantoea ananatis and Enterobacter cloacae and moderate activity by three others, while just one isolate from Arka Vikas (P. oleovorans showed strong antagonism. Validation for the presence of bacterial endophytes on three R cultivars (Arka Alok, Arka Ananya, Arka Samrat showed 8-9 antagonistic bacteria in them in comparison with four species in the three S cultivars (Arka Ashish, Arka Meghali, Arka Saurabhav. Altogether 34 isolates belonging to five classes, 16 genera and 27 species with 23 of them exhibiting pathogen antagonism were isolated from the four R cultivars against 17 isolates under three classes, seven genera and 13 species from the four S cultivars with eight isolates displaying antagonistic effects. The prevalence of higher endophytic bacterial diversity and more antagonistic organisms associated with the seedling roots of resistant cultivars over susceptible genotypes suggest a possible role by the root-associated endophytes in natural defense against the

  3. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

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    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  4. Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis

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    Geun Cheol eSong

    2015-10-01

    Full Text Available 3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 M and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR gene expression levels associated with defense signaling through SA, JA, and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved salicylic acid (SA and jasmonic acid (JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

  5. Molecular characterization of Xanthomonas strains responsible for bacterial leaf spot of tomato in Ethiopia

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    Bacterial spot of tomato (BST) is a major constraint to tomato production in Ethiopia and many other countries leading to significant crop losses. In the present study, using pathogenicity tests, sensitivity to copper and streptomycin, and multilocus sequence analysis, a diverse group of Xanthomonas...

  6. Role of soil, crop debris, and a plant pathogen in Salmonella enterica contamination of tomato plants.

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    Jeri D Barak

    Full Text Available BACKGROUND: In the U.S., tomatoes have become the most implicated vehicle for produce-associated Salmonellosis with 12 outbreaks since 1998. Although unconfirmed, trace backs suggest pre-harvest contamination with Salmonella enterica. Routes of tomato crop contamination by S. enterica in the absence of direct artificial inoculation have not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: This work examined the role of contaminated soil, the potential for crop debris to act as inoculum from one crop to the next, and any interaction between the seedbourne plant pathogen Xanthomonas campestris pv. vesicatoria and S. enterica on tomato plants. Our results show S. enterica can survive for up to six weeks in fallow soil with the ability to contaminate tomato plants. We found S. enterica can contaminate a subsequent crop via crop debris; however a fallow period between crop incorporation and subsequent seeding can affect contamination patterns. Throughout these studies, populations of S. enterica declined over time and there was no bacterial growth in either the phyllosphere or rhizoplane. The presence of X. campestris pv. vesicatoria on co-colonized tomato plants had no effect on the incidence of S. enterica tomato phyllosphere contamination. However, growth of S. enterica in the tomato phyllosphere occurred on co-colonized plants in the absence of plant disease. CONCLUSIONS/SIGNIFICANCE: S. enterica contaminated soil can lead to contamination of the tomato phyllosphere. A six week lag period between soil contamination and tomato seeding did not deter subsequent crop contamination. In the absence of plant disease, presence of the bacterial plant pathogen, X. campestris pv. vesicatoria was beneficial to S. enterica allowing multiplication of the human pathogen population. Any event leading to soil contamination with S. enterica could pose a public health risk with subsequent tomato production, especially in areas prone to bacterial spot disease.

  7. Molecular detection of human bacterial pathogens

    National Research Council Canada - National Science Library

    Liu, Dongyou

    2011-01-01

    .... Molecular Detection of Human Bacterial Pathogens addresses this issue, with international scientists in respective bacterial pathogen research and diagnosis providing expert summaries on current...

  8. Plant-derived Antibacterial Metabolites Suppressing Tomato Bacterial Wilt Caused by Ralstonia solanacearum

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    Thuy Thu Vu

    2017-06-01

    Full Text Available Ralstonia solanacearum species complex (RSSC causes bacterial wilt, and it is one of the most important soil-borne plant pathogenic bacteria. RSSC has a large host range of more than 50 botanical families, which represent more than 200 plant species, including tomato. It is difficult to control bacterial wilt due to following reasons: the bacterial wilt pathogen can grow inside the plant tissue, and it can also survive in soil for a long period; moreover, it has a wide host range and biological diversity. In most previous studies, scientists have focused on developing biological control agents, such as antagonistic microorganisms and botanical materials. However, biocontrol attempts are not successful. Plant-derived metabolites and extracts have been promising candidates to environmentally friendly control bacterial wilt diseases. Therefore, we review the plant extracts, essential oils, and secondary metabolites that show potent in vivo antibacterial activities (in potted plants or in field against tomato bacterial wilt, which is caused by RSSC.

  9. The plant pathogen Pseudomonas syringae pv. tomato is genetically monomorphic and under strong selection to evade tomato immunity.

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    Rongman Cai

    2011-08-01

    Full Text Available Recently, genome sequencing of many isolates of genetically monomorphic bacterial human pathogens has given new insights into pathogen microevolution and phylogeography. Here, we report a genome-based micro-evolutionary study of a bacterial plant pathogen, Pseudomonas syringae pv. tomato. Only 267 mutations were identified between five sequenced isolates in 3,543,009 nt of analyzed genome sequence, which suggests a recent evolutionary origin of this pathogen. Further analysis with genome-derived markers of 89 world-wide isolates showed that several genotypes exist in North America and in Europe indicating frequent pathogen movement between these world regions. Genome-derived markers and molecular analyses of key pathogen loci important for virulence and motility both suggest ongoing adaptation to the tomato host. A mutational hotspot was found in the type III-secreted effector gene hopM1. These mutations abolish the cell death triggering activity of the full-length protein indicating strong selection for loss of function of this effector, which was previously considered a virulence factor. Two non-synonymous mutations in the flagellin-encoding gene fliC allowed identifying a new microbe associated molecular pattern (MAMP in a region distinct from the known MAMP flg22. Interestingly, the ancestral allele of this MAMP induces a stronger tomato immune response than the derived alleles. The ancestral allele has largely disappeared from today's Pto populations suggesting that flagellin-triggered immunity limits pathogen fitness even in highly virulent pathogens. An additional non-synonymous mutation was identified in flg22 in South American isolates. Therefore, MAMPs are more variable than expected differing even between otherwise almost identical isolates of the same pathogen strain.

  10. Antagonistic activity of Bacillus subtilis SB1 and its biocontrol effect on tomato bacterial wilt

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    A potential biocontrol agent of bacterial wilt, Bacillus subtilis SB1, isolated from tomato roots, showed a broad-spectrum of antimicrobial activity in in vitro experiments. It inhibited the growth of many plant pathogens, including Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, Fusarium ox...

  11. The potential of endomycorrhizal fungi in controlling tomato bacterial ...

    African Journals Online (AJOL)

    The impact of colonization by three mycorrhizal fungi on tomato bacterial wilt caused by Ralstonia solanaceraum was investigated. Three species of arbuscular mycorrhizal fungal (AMF) were tested (Glomus mosseae, Scutellospora sp. and Gigaspora margarita). Siginificant differences in tomato growth based on plant ...

  12. Phosphorylation and proteome dynamics in pathogen-resistant tomato plants

    NARCIS (Netherlands)

    Stulemeijer, I.J.E.

    2008-01-01

    Microbial plant pathogens impose a continuous threat on global food production. Similar to disease resistance in mammals, an innate immune system allows plants to recognise pathogens and swiftly activate defence. For the work described in this thesis, the interaction between tomato and the

  13. Pathogenicity of «Phytophthora nicotianae» Isolates to Tobacco and Tomato Cultivars

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    Kalomira Elena

    2000-01-01

    Sixty-one isolates of Phytophthora nicotianae were tested for pathogenicity to tobacco and tomato. All the isolates but one from tobacco were pathogenic to tobacco but none of the isolates from tobacco were pathogenic to tomato. Of the 53 isolates from non tobacco hosts, 19 proved pathogenic to tomato. Seven isolates from different non tobacco hosts colonized the tobacco stem and produced necrosis but not black shank. Five isolates colonized the tomato stem without causing disease...

  14. Pseudomonas syringae pv. tomato: the right pathogen, of the right plant, at the right time.

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    Preston, G M

    2000-09-01

    Abstract Pseudomonas syringae pv. tomato and the closely related pathovar P. s. pv. maculicola have been the focus of intensive research in recent years, not only because of the diseases they cause on tomato and crucifers, but because strains such as P. s. pv. tomato DC3000 and P. s. pv. maculicola ES4326 are pathogens of the model plant Arabidopsis thaliana. Consequently, both P. s. pv. tomato and P. s. pv. maculicola have been widely used to study the molecular mechanisms of host responses to infection. Analyses of the molecular basis of pathogenesis in P. s. pv. tomato reveal a complex and intimate interaction between bacteria and plant cells that depends on the coordinated expression of multiple pathogenicity and virulence factors. These include toxins, extracellular proteins and polysaccharides, and the translocation of proteins into plant cells by the type III (Hrp) secretion system. The contribution of individual virulence factors to parasitism and disease development varies significantly between strains. Application of functional genomics and cell biology to both pathogen and host within the P. s. pv. tomato/A. thaliana pathosystem provides a unique opportunity to unravel the molecular interactions underlying plant pathogenesis. Taxonomic relationship: Bacteria; Proteobacteria; gamma subdivision; Pseudomonadaceae/Moraxellaceae group; Pseudomonadaceae family; Pseudomonas genus; Pseudomonas syringae species; tomato pathovar. Microbiological properties: Gram-negative, aerobic, motile, rod-shaped, polar flagella, oxidase negative, arginine dihydrolase negative, DNA 58-60 mol% GC, elicits the hypersensitive response on tobacco. Primarily studied as the causal agent of bacterial speck of tomato and as a model pathogen of A. thaliana, although it has been isolated from a wide range of crop and weed species. Disease symptoms: Tomato (Lycopersicon esculentum): Brown-black leaf spots sometimes surrounded by chlorotic margin; dark superficial specks on green fruit

  15. Bacterial reproductive pathogens of cats and dogs.

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    Graham, Elizabeth M; Taylor, David J

    2012-05-01

    With the notable exception of Brucella canis, exogenous bacterial pathogens are uncommon causes of reproductive disease in cats and dogs. Most bacterial reproductive infections are endogenous, and predisposing factors for infection are important. This article reviews the etiology, pathogenesis, clinical presentation, diagnosis, treatment, and public health significance of bacterial reproductive pathogens in cats and dogs.

  16. Characterization of resistant tomato mutants to bacterial canker ...

    African Journals Online (AJOL)

    Yomi

    2012-04-19

    Apr 19, 2012 ... A small scale ethylmethanesulfonate (EMS) mutation was used to obtain resistant mutant plants to bacterial canker disease caused by Clavibacter michiganensis subsp. michiganensis isolate 2 (Cmm2). Susceptible EBR3 tomato line (200) seeds were mutagenised with the chemical EMS. Of the ...

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

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

    2011-01-01

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

  18. Effects of simulated packing house operating conditions on pathogen internalization in tomatoes

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    Introduction: Food-borne illness outbreaks associated with Salmonella enterica have been traced back to tomatoes contaminated through bacterial attachment and possible internalization during post-harvest handling. However, no scientific information is available regarding the effect of current tomato...

  19. Novel components of leaf bacterial communities of field-grown tomato plants and their potential for plant growth promotion and biocontrol of tomato diseases.

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    Romero, Fernando M; Marina, María; Pieckenstain, Fernando L

    2016-04-01

    This work aimed to characterize potentially endophytic culturable bacteria from leaves of cultivated tomato and analyze their potential for growth promotion and biocontrol of diseases caused by Botrytis cinerea and Pseudomonas syringae. Bacteria were obtained from inner tissues of surface-disinfected tomato leaves of field-grown plants. Analysis of 16S rRNA gene sequences identified bacterial isolates related to Exiguobacterium aurantiacum (isolates BT3 and MT8), Exiguobacterium spp. (isolate GT4), Staphylococcus xylosus (isolate BT5), Pantoea eucalypti (isolate NT6), Bacillus methylotrophicus (isolate MT3), Pseudomonas veronii (isolates BT4 and NT2), Pseudomonas rhodesiae (isolate BT2) and Pseudomonas cichorii (isolate NT3). After seed inoculation, BT2, BT4, MT3, MT8, NT2 and NT6 were re-isolated from leaf extracts. NT2, BT2, MT3 and NT6 inhibited growth of Botrytis cinerea and Pseudomonas syringae pv. tomato in vitro, produced antimicrobial compounds and reduced leaf damage caused by B. cinerea. Some of these isolates also promoted growth of tomato plants, produced siderophores, the auxin indole-3-acetic and solubilized inorganic phosphate. Thus, bacterial communities of leaves from field-grown tomato plants were found to harbor potentially endophytic culturable beneficial bacteria capable of antagonizing pathogenic microorganisms and promoting plant growth, which could be used as biological control agents and biofertilizers/biostimulators for promotion of tomato plant growth. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  20. Heme Synthesis and Acquisition in Bacterial Pathogens

    OpenAIRE

    Choby, Jacob E.; Skaar, Eric P.

    2016-01-01

    Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host source...

  1. Heme Synthesis and Acquisition in Bacterial Pathogens.

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    Choby, Jacob E; Skaar, Eric P

    2016-08-28

    Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Selection and Characterization of Endophytic Bacteria as Biocontrol Agents of Tomato Bacterial Wilt Disease

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    ABDJAD ASIH NAWANGSIH

    2011-06-01

    Full Text Available Biological control of bacterial wilt pathogen (Ralstonia solanacearum of tomato using endophytic bacteria is one of the alternative control methods to support sustainable agriculture. This study was conducted to select and characterize endophytic bacteria isolated from healthy tomato stems and to test their ability to promote plant growth and suppress bacterial wilt disease. Among 49 isolates successfully isolated, 41 were non-plant pathogenic. Green house test on six selected isolates based on antagonistic effect on R. solanacearum or ability to suppress R. solanacearum population in dual culture assays obtained BC4 and BL10 isolates as promising biocontrol agents. At six weeks after transplanting, plants treated with BC4 isolate showed significantly lower disease incidence (33% than that of control (83%. Plants height was not significantly affected by endophytic bacterial treatments. Based on 16S rRNA sequence, BC4 isolate had 97% similarity with Staphylococcus epidermidis (accession number EU834240.1, while isolate BL10 had 98% similarity with Bacillus amyloliquefaciens strain JK-SD002 (accession number AB547229.1.

  3. Use of Bacteriophages to control bacterial pathogens

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    Lytic bacteriophages can provide a natural method and an effective alternative to antibiotics to reduce bacterial pathogens in animals, foods, and other environments. Bacteriophages (phages) are viruses which infect bacterial cells and eventually kill them through lysis, and represent the most abun...

  4. Plant Pathogen-Induced Water-Soaking Promotes Salmonella enterica Growth on Tomato Leaves

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    Potnis, Neha; Colee, James; Jones, Jeffrey B.

    2015-01-01

    Plant pathogen infection is a critical factor for the persistence of Salmonella enterica on plants. We investigated the mechanisms responsible for the persistence of S. enterica on diseased tomato plants by using four diverse bacterial spot Xanthomonas species that differ in disease severities. Xanthomonas euvesicatoria and X. gardneri infection fostered S. enterica growth, while X. perforans infection did not induce growth but supported the persistence of S. enterica. X. vesicatoria-infected leaves harbored S. enterica populations similar to those on healthy leaves. Growth of S. enterica was associated with extensive water-soaking and necrosis in X. euvesicatoria- and X. gardneri-infected plants. The contribution of water-soaking to the growth of S. enterica was corroborated by an increased growth of populations on water-saturated leaves in the absence of a plant pathogen. S. enterica aggregates were observed with bacterial spot lesions caused by either X. euvesicatoria or X. vesicatoria; however, more S. enterica aggregates formed on X. euvesicatoria-infected leaves as a result of larger lesion sizes per leaf area and extensive water-soaking. Sparsely distributed lesions caused by X. vesicatoria infection do not support the overall growth of S. enterica or aggregates in areas without lesions or water-soaking; S. enterica was observed as single cells and not aggregates. Thus, pathogen-induced water-soaking and necrosis allow S. enterica to replicate and proliferate on tomato leaves. The finding that the pathogen-induced virulence phenotype affects the fate of S. enterica populations in diseased plants suggests that targeting of plant pathogen disease is important in controlling S. enterica populations on plants. PMID:26386057

  5. Application of low frequency pulsed ohmic heating for inactivation of foodborne pathogens and MS-2 phage in buffered peptone water and tomato juice.

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    Kim, Sang-Soon; Choi, Won; Kang, Dong-Hyun

    2017-05-01

    The purpose of this study was to inactivate foodborne pathogens effectively by ohmic heating in buffered peptone water and tomato juice without causing electrode corrosion and quality degradation. Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes were used as representative foodborne pathogens and MS-2 phage was used as a norovirus surrogate. Buffered peptone water and tomato juice inoculated with pathogens were treated with pulsed ohmic heating at different frequencies (0.06-1 kHz). Propidium iodide uptake values of bacterial pathogens were significantly (p heating is applicable to inactivate foodborne pathogens effectively without causing electrode corrosion and quality degradation in tomato juice. Copyright © 2016. Published by Elsevier Ltd.

  6. Photoinactivation of major bacterial pathogens in aquaculture

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    Heyong Jin Roh

    2016-08-01

    Full Text Available Abstract Background Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and 68.4 J cm−2, respectively, produced one log reduction in the bacterial populations, whereas Streptococcus parauberis was the least susceptible (153.8 J cm−2 per one log reduction. In general, optical density (OD values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

  7. Phytobiocidal management of bacterial wilt of tomato caused by Ralstonia solanacearum (Smith) Yabuuchi

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    Din, N.; Ahmad, M.; Siddique, M.; Ali, A.; Naz, I.; Ullah, N.; Ahmad, F.

    2016-11-01

    Phytobiocides are a good alternative to chemicals in managing bacterial diseases including bacterial wilt of tomato caused by Ralstonia solanacearum. In the present research study, finely ground dried powders of seven widely available medicinal plants/weeds species viz., Peganum harmala (esfand or wild rue), Calotropis procera (sodom apple), Melia azedarach (white cedar), Allium sativum (garlic), Adhatoda vasica (malabar nut), Tagetes patula (marigold) and Nerium oleander (oleander) were assessed for their anti-microbial activity, both in-vitro (10% w/v) and in-vivo (10, 20, 30, and 40 g/kg of potted soil) against R. solanacearum. Aqueous extracts (prepared as 10% w/v, soaking for 48-72 h and filtering) of C. procera, A. vasica, and T. patula inhibited the in-vitro growth of the bacterial pathogen over 60% of that produced by the standard antibiotic streptomycin. A. sativum, N. oleander and P. harmala aqueous extracts were less effective while M. azedarach showed no effect against R. solanacearum. The higher dose (40 g/kg of soil) of C. procera, A. vasica and T. patula decreased disease severity quite effectively and increased yield and plant growth characters as much as the standard antibiotic did. No phytotoxicity of medicinal plants powder was observed on tomato plants. Alkaloids, flavonoids, tannins, saponins and terpenoids were detected in the aqueous extracts of T. patula and A. vasica whereas C. procera was found to have only alkaloids, flavonoids, tannins and saponins. Our data suggest that dried powders of T. patula, C. procera and A. vasica (40 g/kg of soil) could be used as an effective component in the integrated disease management programs against bacterial wilt of tomato. (Author)

  8. Phytobiocidal management of bacterial wilt of tomato caused by Ralstonia solanacearum (Smith Yabuuchi

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    Naseerud Din

    2016-08-01

    Full Text Available Phytobiocides are a good alternative to chemicals in managing bacterial diseases including bacterial wilt of tomato caused by Ralstonia solanacearum. In the present research study, finely ground dried powders of seven widely available medicinal plants/weeds species viz., Peganum harmala (esfand or wild rue, Calotropis procera (sodom apple, Melia azedarach (white cedar, Allium sativum (garlic, Adhatoda vasica (malabar nut, Tagetes patula (marigold and Nerium oleander (oleander were assessed for their anti-microbial activity, both in-vitro (10% w/v and in-vivo (10, 20, 30, and 40 g/kg of potted soil against R. solanacearum. Aqueous extracts (prepared as 10% w/v, soaking for 48-72 h and filtering of C. procera, A. vasica, and T. patula inhibited the in-vitro growth of the bacterial pathogen over 60% of that produced by the standard antibiotic streptomycin. A. sativum, N. oleander and P. harmala aqueous extracts were less effective while M. azedarach showed no effect against R. solanacearum. The higher dose (40 g/kg of soil of C. procera, A. vasica and T. patula decreased disease severity quite effectively and increased yield and plant growth characters as much as the standard antibiotic did. No phytotoxicity of medicinal plants powder was observed on tomato plants. Alkaloids, flavonoids, tannins, saponins and terpenoids were detected in the aqueous extracts of T. patula and A. vasica whereas C. procera was found to have only alkaloids, flavonoids, tannins and saponins. Our data suggest that dried powders of T. patula, C. procera and A. vasica (40 g/kg of soil could be used as an effective component in the integrated disease management programs against bacterial wilt of tomato.

  9. Molecular Mechanisms of Bacterial Pathogenicity

    Science.gov (United States)

    Fuchs, Thilo Martin

    Cautious optimism has arisen over recent decades with respect to the long struggle against bacteria, viruses, and parasites. This has been offset, however, by a fatal complacency stemming from previous successes such as the development of antimicrobial drugs, the eradication of smallpox, and global immunization programs. Infectious diseases nevertheless remain the world's leading cause of death, killing at least 17 million persons annually [61]. Diarrheal diseases caused by Vibrio cholerae or Shigella dysenteriae kill about 3 million persons every year, most of them young children: Another 4 million die of tuberculosis or tetanus. Outbreaks of diphtheria in Eastern Europe threatens the population with a disease that had previously seemed to be overcome. Efforts to control infectious diseases more comprehensively are undermined not only by socioeconomic conditions but also by the nature of the pathogenic organisms itself; some isolates of Staphylococcus aureus and Enterobacter have become so resistant to drugs by horizontal gene transfer that they are almost untreatable. In addition, the mechanism of genetic variability helps pathogens to evade the human immune system, thus compromising the development of powerful vaccines. Therefore detailed knowledge of the molecular mechanisms of microbial pathogenicity is absolutely necessary to develop new strategies against infectious diseases and thus to lower their impact on human health and social development.

  10. Coronatine inhibits stomatal closure and delays hypersensitive response cell death induced by nonhost bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Seonghee Lee

    2013-02-01

    Full Text Available Pseudomonas syringae is the most widespread bacterial pathogen in plants. Several strains of P. syringae produce a phytotoxin, coronatine (COR, which acts as a jasmonic acid mimic and inhibits plant defense responses and contributes to disease symptom development. In this study, we found that COR inhibits early defense responses during nonhost disease resistance. Stomatal closure induced by a nonhost pathogen, P. syringae pv. tabaci, was disrupted by COR in tomato epidermal peels. In addition, nonhost HR cell death triggered by P. syringae pv. tabaci on tomato was remarkably delayed when COR was supplemented along with P. syringae pv. tabaci inoculation. Using isochorismate synthase (ICS-silenced tomato plants and transcript profiles of genes in SA- and JA-related defense pathways, we show that COR suppresses SA-mediated defense during nonhost resistance.

  11. Transgenic resistance confers effective field level control of bacterial spot disease in tomato.

    Directory of Open Access Journals (Sweden)

    Diana M Horvath

    Full Text Available We investigated whether lines of transgenic tomato (Solanum lycopersicum expressing the Bs2 resistance gene from pepper, a close relative of tomato, demonstrate improved resistance to bacterial spot disease caused by Xanthomonas species in replicated multi-year field trials under commercial type growing conditions. We report that the presence of the Bs2 gene in the highly susceptible VF 36 background reduced disease to extremely low levels, and VF 36-Bs2 plants displayed the lowest disease severity amongst all tomato varieties tested, including commercial and breeding lines with host resistance. Yields of marketable fruit from transgenic lines were typically 2.5 times that of the non-transformed parent line, but varied between 1.5 and 11.5 fold depending on weather conditions and disease pressure. Trials were conducted without application of any copper-based bactericides, presently in wide use despite negative impacts on the environment. This is the first demonstration of effective field resistance in a transgenic genotype based on a plant R gene and provides an opportunity for control of a devastating pathogen while eliminating ineffective copper pesticides.

  12. Incidence of Bacterial Pathogens following Biomechanical ...

    African Journals Online (AJOL)

    A correlation exists between endodontic microflora in pulpal disease and endodontic treatment failure. This study presents data on the recoverable bacterial pathogens following biomechanical treatment of infected root canals. Standard endodontic procedure were used to access tooth pulp cavity, processed and fluid ...

  13. teaching hospital: common bacterial pathogens seen.

    African Journals Online (AJOL)

    pathogens in pyogenic meningitis. Most of the delivery occurred outside the teaching hospital, even those that delivered in the hospital, some come in during labour. ' _ Conclusion: Neonatal bacterial infections are still a cause of high morbidity and mortality of the newborn in our setting. To reduce the morbidity and mortality ...

  14. Microbial minimalism: genome reduction in bacterial pathogens.

    Science.gov (United States)

    Moran, Nancy A

    2002-03-08

    When bacterial lineages make the transition from free-living or facultatively parasitic life cycles to permanent associations with hosts, they undergo a major loss of genes and DNA. Complete genome sequences are providing an understanding of how extreme genome reduction affects evolutionary directions and metabolic capabilities of obligate pathogens and symbionts.

  15. Tomato SlGGP-LIKE gene participates in plant responses to chilling stress and pathogenic infection.

    Science.gov (United States)

    Yang, Dong-Yue; Li, Meng; Ma, Na-Na; Yang, Xing-Hong; Meng, Qing-Wei

    2017-03-01

    Plants are always exposed to abiotic and biotic stresses which can adversely affect their growth and development. As an important antioxidant, AsA plays a vital role in plant defence against damage caused by stresses. In this study, we cloned a tomato GDP- L -galactose phosphorylase-like (SlGGP-LIKE) gene and investigated its role in resistance to abiotic and biotic stresses by using antisense transgenic (AS) tomato lines. The AsA content in AS plants was lower than that in WT plants. Under chilling stress, the growth of AS plants was inhibited significantly, and they yielded higher levels of ROS, REC and MDA but demonstrated weaker APX activity than that shown by WT plants. Additionally, the declined values of Pn, Fv/Fm, oxidisable P700, and D1 protein content of PSII in AS lines were significant. Furthermore, the effect on xanthophyll cycle of AS plants was more severe than that on WT plants, and the ratio of zeaxanthin (Z)/(V + A + Z) and (Z + 0.5 A)/(V + A + Z) in AS lines was lower than that in WT plants. In spite of chilling stress, under Pseudomonas syringae pv.tomato (Pst) DC3000 strain infection, AS plants showed lesser bacterial cell growth and dead cells than those shown by WT plants. This finding indicated that AS plants demonstrated stronger resistance against pathogenic infection. Results suggest that SlGGP-LIKE gene played an important role in plant defence against chilling stress and pathogenic infection. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Exploiting Quorum Sensing To Confuse Bacterial Pathogens

    Science.gov (United States)

    LaSarre, Breah

    2013-01-01

    SUMMARY Cell-cell communication, or quorum sensing, is a widespread phenomenon in bacteria that is used to coordinate gene expression among local populations. Its use by bacterial pathogens to regulate genes that promote invasion, defense, and spread has been particularly well documented. With the ongoing emergence of antibiotic-resistant pathogens, there is a current need for development of alternative therapeutic strategies. An antivirulence approach by which quorum sensing is impeded has caught on as a viable means to manipulate bacterial processes, especially pathogenic traits that are harmful to human and animal health and agricultural productivity. The identification and development of chemical compounds and enzymes that facilitate quorum-sensing inhibition (QSI) by targeting signaling molecules, signal biogenesis, or signal detection are reviewed here. Overall, the evidence suggests that QSI therapy may be efficacious against some, but not necessarily all, bacterial pathogens, and several failures and ongoing concerns that may steer future studies in productive directions are discussed. Nevertheless, various QSI successes have rightfully perpetuated excitement surrounding new potential therapies, and this review highlights promising QSI leads in disrupting pathogenesis in both plants and animals. PMID:23471618

  17. Bacteriophages for detection of bacterial pathogens

    International Nuclear Information System (INIS)

    Kutateladze, M.

    2009-01-01

    The G. Eliava Institute of Bacteriophages, Microbiology and Virology (Tbilisi, Georgia) is one of the most famous institutions focused on bacteriophage research for the elaboration of appropriate phage methodologies for human and animal protection. The main direction of the institute is the study and production of bacteriophages against intestinal disorders (dysentery, typhoid, intesti) and purulent-septic infections (staphylococcus, streptococcus, pyophage, etc.). These preparations were successfully introduced during the Soviet era, and for decades were used throughout the former Soviet Union and in other Socialist countries for the treatment, prophylaxis, and diagnosis of various infectious diseases, including those caused by antibiotic-resistant bacterial strains. Bacteriophages were widely used for identifying and detecting infections caused by the most dangerous pathogens and causative agents of epidemiological outbreaks. The specific topic of this presentation is the phage typing of bacterial species, which can be an important method for epidemiological diagnostics. Together with different genetic methodologies - such as PCR-based methods, PFGE, plasmid fingerprinting, and ribosomal typing - phage typing is one method for identifying bacterial pathogens. The method has a high percentage of determination of phage types, high specificity of reaction, and is easy for interpretation and use by health workers. Phage typing was applied for inter-species differentiation of different species of Salmonella, S. typhi, Brucella spp, Staphylococcus aureus, E. col,i Clostridium deficile, Vibrio cholerae, Yersinia pestis, Yersinia enterocolitica, Lysteria monocytogenes, Clostridium perfringens, Clostridium tetani, plant pathogens, and other bacterial pathogens. In addition to addressing the utility and efficacy of phage typing, the paper will discuss the isolation and selection of diagnostic typing phages for interspecies differentiation of pathogens that is necessary

  18. Effects of Biochar Amendment on Tomato Bacterial Wilt Resistance and Soil Microbial Amount and Activity

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2016-01-01

    Full Text Available Bacterial wilt is a serious soilborne disease of Solanaceae crops which is caused by Ralstonia solanacearum. The important role of biochar in enhancing disease resistance in plants has been verified; however, the underlying mechanism remains not fully understood. In this study, two different biochars, made from peanut shell (BC1 and wheat straw (BC2, were added to Ralstonia solanacearum-infected soil to explore the interrelation among biochar, tomato bacterial wilt, and soil microbial properties. The results showed that both BC1 and BC2 treatments significantly reduced the disease index of bacterial wilt by 28.6% and 65.7%, respectively. The populations of R. solanacearum in soil were also significantly decreased by biochar application. Ralstonia solanacearum infection significantly reduced the densities of soil bacteria and actinomycetes and increased the ratio of soil fungi/bacteria in the soil. By contrast, BC1 and BC2 addition to pathogen-infected soil significantly increased the densities of soil bacteria and actinomycetes but decreased the density of fungi and the ratios of soil fungi/bacteria and fungi/actinomycetes. Biochar treatments also increased soil neutral phosphatase and urease activity. Furthermore, higher metabolic capabilities of microorganisms by biochar application were found at 96 and 144 h in Biolog EcoPlates. These results suggest that both peanut and wheat biochar amendments were effective in inhibiting tomato bacterial wilt caused by R. solanacearum. The results suggest a relationship between the disease resistance of the plants and the changes in soil microbial population densities and activity.

  19. Formaldehyde stress responses in bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Nathan Houqian Chen

    2016-03-01

    Full Text Available Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed.

  20. Molecular identification of pathogenic Fusarium species, the causal agents of tomato wilt in western Iran

    Directory of Open Access Journals (Sweden)

    Chehri Khosrow

    2016-04-01

    Full Text Available Fusarium species are causal agents of fungal diseases occurring frequently in numerous agriculturally important plants, including potato, garlic and are one of the common pathogens of tomato, causing root rot in the west part of Iran. Therefore, the objectives of this study were to isolate and identify disease-causing Fusarium species from infected tomatoes based on the morphological and molecular characteristics. Twenty-five isolates of Fusarium were obtained from infected root of tomato plants collected from the fields in different regions of western Iran. Based on morphological features, the strains were classified into four following Fusarium species: F. oxysporum, F. redolens, F. proliferatum and F. verticillioides. The phylogenetic trees based on tef1 and tub2 dataset clearly distinguished closely related species. All of the isolates were evaluated for their pathogenicity on healthy tomato seedlings in the greenhouse. This is the first report on molecular identification of Fusarium species isolated from tomato plants cultivated in Iran.

  1. Cellphones A Modern Stayhouse For Bacterial Pathogens

    OpenAIRE

    Usha Arora; Pushpa Devi; Aarti Chadha; Sita Malhotra

    2009-01-01

    Cellphones are increasingly used by health care personnels for communication. These can harbour variouspotential pathogens and become an exogenous source of nosocomial infections. A total of 160 cellphonesbelonging to doctors and paramedical staff working in various departments at govt. medical college andhospital, Amritsar were screened for bacterial isolates. Sterile swabs moistened with nutrient broth wereused to swab the front, back and the sides of the cellphones and were subjected to cu...

  2. The intrinsic resistome of bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Jorge Andrés Olivares Pacheco

    2013-04-01

    Full Text Available Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally a low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyse recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.

  3. The SA-dependent defense pathway is active against different pathogens in tomato and tobacco.

    Science.gov (United States)

    Achuo, A E; Audenaert, K; Meziane, H; Höfte, M

    2002-01-01

    The importance of salicylic acid (SA) in plant defense against pathogen attack has been elaborately documented. Benzothiadiazole (BTH, BION), a chemical analogue of SA, also induces resistance through the SA-dependent pathway. We investigated the role of SA in both basal defense and induced resistance of tomato (Lycopersicon esculentum) and tobacco (Nicotiana tabacum) against Oidium neolycopersici (a biotrophic pathogen) and Botrytis cinerea (a necrotrophic pathogen). A comparison of NahG transgenic tomato and tobacco (unable to accumulate SA) to their respective wild types revealed that in both crops, SA was not involved in basal defense against O. neolycopersici. SA also played no role in the basal defense of tobacco against B. cinerea but NahG tomato plants were significantly more sensitive to B. cinerea than wild type plants. Activation of the SA-dependent defense pathway via BTH resulted in induced resistance against B. cinerea in tomato but not in tobacco. In contrast, BTH induced resistance against O. neolycopersci in tobacco but not in tomato. Microscopic analysis revealed that BTH treatment could prevent penetration of the odium germ tube through the epidermal cell wall of tobacco leaves whereas penetration was successful on tomato leaves, irrespective of BTH treatment. We conclude that even in two related plant species such as tomato and tobacco, the SA-dependent defense pathway does not trigger the same defense responses. It also means that the outcome of a BTH treatment cannot be predicted and has to be tested for each plant-pathogen combination.

  4. Bacterial diseases of tomato plants in terms of open and covered growing of Ukraine

    Directory of Open Access Journals (Sweden)

    J.V. Kolomiets

    2017-06-01

    Full Text Available It was established that the main causes of mass diseases of tomato in covered ground in Ukraine are agents of bacterial black spotting, bacterial speck and in open ground are agent of bacterial cancer of tomato plants. Typical symptoms of diseases are wilting and die-off of young plants, blackening of fiber vascular bundles, black spotting of leaves and fruits, and fruit stem rot. It was studied morphological and cultural, as well as physiological and biochemical properties of the selected strains of the agents of tomato bacterial diseases. We recommended biological preparations Phytocide and Phytohelp based on the bacteria Bacillus subtilis, to restrict the development of the agents of bacterial black spotting Xanthomonas vesicatoria and bacterial cancer Clavibacter michiganensis subsp. michiganensis.

  5. Effect of a Bacterial Grass Culture on the Plant Growth and Disease Control in Tomato

    Directory of Open Access Journals (Sweden)

    Yong Seong Lee

    2017-12-01

    Full Text Available This study aimed to investigate the plant growth-promoting and biocontrol potential of a grass culture with Paenibacillus ehimensis KWN8 on tomato. For this experiment, treatments of a chemical fertilizer (F, a bacterial grass culture (G, a 1/3 volume of G plus 2/3 F (GF, and F plus a synthetic fungicide (FSf were applied to tomato leaves and roots. The result showed that the severity of Alternariasolani and Botrytiscinerea symptoms were significantly reduced after the application of the bacterial grass culture (G and GF and FSf. In addition, root mortality in G and GF was lower compared to F. Tomato plants treated with G or GF had better vegetative growth and yield compared to F. Application of G affected the fungal and bacterial populations in the soil. In conclusion, treatment with a bacterial grass culture decreased disease severity and increased tomato growth parameters. However, there were no statistically significant correlations between disease occurrence and tomato yields. This experiment presents the possibility to manage diseases of tomato in an environmentally friendly manner and to also increase the yield of tomato by using a grass culture broth containing P. ehimensis KWN38.

  6. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  7. Differential Control Efficacies of Vitamin Treatments against Bacterial Wilt and Grey Mould Diseases in Tomato Plants

    Directory of Open Access Journals (Sweden)

    Jeum Kyu Hong

    2016-10-01

    Full Text Available Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea, respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1, niacin (vitamin B3, pyridoxine (vitamin B6, and menadione (vitamin K3. In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure (10⁶ colony-forming unit [cfu]/ml. Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea. The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea. Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.

  8. Bacterial toxins as pathogen weapons against phagocytes

    Directory of Open Access Journals (Sweden)

    Ana edo Vale

    2016-02-01

    Full Text Available Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favour microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signalling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.

  9. The AVR9 elicitor peptide of the tomato pathogen Cladosporium fulvum : molecular aspects of recognition

    NARCIS (Netherlands)

    Kooman - Gersmann, M.

    1998-01-01

    The interaction between the fungal pathogen Cladosporium fulvum and tomato has been used as a model system to study the molecular basis of gene-for-gene relationships. C. fulvum is a specialized, biotrophic pathogen, which causes leaf mold on

  10. Bacterial community diversity and variation in spray water sources and the tomato fruit surface

    Directory of Open Access Journals (Sweden)

    Ottesen Andrea R

    2011-04-01

    Full Text Available Abstract Background Tomato (Solanum lycopersicum consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. Results The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Conclusions Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an

  11. Control of wilt and rot pathogens of tomato by antagonistic pink pigmented facultative methylotrophic Delftia lacustris and Bacillus spp.

    Directory of Open Access Journals (Sweden)

    Veeranan Janahiraman

    2016-11-01

    Full Text Available The studies on the biocontrol potential of pink pigmented facultative methylotrophic (PPFM bacteria other than the genus Methylobacterium are scarce. In the present study, we report three facultative methylotrophic isolates; PPO-1, PPT-1 and PPB-1, respectively identified as Delftia lacustris, Bacillus subtilis and Bacillus cereus by 16S rRNA gene sequence analysis. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicates that the isolates PPO-1, PPT-1 and PPB-1 are not pathogenic strains. Under in vitro conditions, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 showed direct antagonistic effect by inhibiting the mycelial growth of fungal pathogens; Fusarium oxysporum f. sp. lycopersici (2.15, 2.05 and 1.95 cm, Sclerotium rolfsii (2.14, 2.04 and1.94 cm, Pythium ultimum (2.12, 2.02 and 1.92cm, and Rhizoctonia solani (2.18, 2.08 and 1.98 cm and also produced volatile inhibitory compounds. Under plant growth chamber condition methylotrophic bacterial isolates; D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 significantly reduced the disease incidence of tomato. Under greenhouse condition, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 inoculated tomato plants, when challenged with F. oxysporum f. sp. lycopersici, S. rolfsii, P. ultimum and R. solani, increased the pathogenesis related proteins (β-1, 3-glucanase and chitinase and defense enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and catalase on day 5 after inoculation. In the current study, we first report the facultative methylotrophy in pink pigmented Delftia lacustris, B. subtilis, and B. cereus and their antagonistic potential against fungal pathogens. Direct antagonistic and ISR effects of these isolates against fungal pathogens of tomato evidenced their possible use as a biocontrol agent.

  12. Water microbiology. Bacterial pathogens and water.

    Science.gov (United States)

    Cabral, João P S

    2010-10-01

    Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water-cholera, typhoid fever and bacillary dysentery-is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  13. Water Microbiology. Bacterial Pathogens and Water

    Directory of Open Access Journals (Sweden)

    João P. S. Cabral

    2010-10-01

    Full Text Available Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers. Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  14. Effects of colonization of a bacterial endophyte, Azospirillum sp. B510, on disease resistance in tomato.

    Science.gov (United States)

    Fujita, Moeka; Kusajima, Miyuki; Okumura, Yasuko; Nakajima, Masami; Minamisawa, Kiwamu; Nakashita, Hideo

    2017-08-01

    A plant growth-promoting bacteria, Azospirillum sp. B510, isolated from rice, can enhance growth and yield and induce disease resistance against various types of diseases in rice. Because little is known about the interaction between other plant species and this strain, we have investigated the effect of its colonization on disease resistance in tomato plants. Treatment with this strain by soil-drenching method established endophytic colonization in root tissues in tomato plant. The endophytic colonization with this strain-induced disease resistance in tomato plant against bacterial leaf spot caused by Pseudomonas syringae pv. tomato and gray mold caused by Botrytis cinerea. In Azospirillum-treated plants, neither the accumulation of SA nor the expression of defense-related genes was observed. These indicate that endophytic colonization with Azospirillum sp. B510 is able to activate the innate immune system also in tomato, which does not seem to be systemic acquired resistance.

  15. Pathogenic bacterial contaminations in hospital cafeteria foods.

    Science.gov (United States)

    Rattanasena, Paweena; Somboonwatthanakul, Issaraporn

    2010-02-01

    This study aims to examine the pathogenic bacterial contaminations in foods sold in hospital cafeteria. A study was conducted between April and September of 2008 using cafeteria located in Mahasarakham provincial hospital, Thailand, as a study area. The cafeteria foods were evaluated for contaminations with Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Streptococcus faecalis, which have been earlier reported to cause nosocomial outbreaks. Of 33 different types of ready-to-eat foods, the majority (54.54%) were found to have bacteria >10(7) colony forming units per gram of food (cfu g(-1)), whereas 36.36% and only 9.10% of them were found to have bacteria at 10(6)-10(7) and foods were also shown to be contaminated with Escherichia coli (57.57%), followed by Streptococcus faecalis (51.51%), Staphylococcus aureus (48.48%) and Salmonella typhimurium (27.27%), respectively. In contrast, of 7 different types of freshly-made foods, the majority (71.42%) were found to have bacterial foods (42.85%), followed by Escherichia coli and Streptococcus faecalis at equal percentages (14.28%). None of the freshly-made foods were found to be contaminated with Streptococcus typhimurium. The results concluded that a number of ready-to-eat foods sold in the Mahasarakham hospital cafeteria were contaminated with several pathogenic bacteria at unacceptable levels. Healthcare authorities should be more aware that ready-to-eat cafeteria foods that are heavily contaminated with pathogenic bacteria may be harmful to healthcare workers and visitors and may result in nosocomial infections of the patients.

  16. Shellfish as reservoirs of bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Harry Hariharan

    2016-04-01

    Full Text Available The objective of this article is to present an overview on bacterial pathogens associated with shellfish in Grenada and other countries including the authors’ experience. Although there have been considerable published work on vibrios, there is a lack of information on Salmonella serovars associated with various shellfish. In Grenada, for instance the blue land crabs collected from their habitats were found to harbor several Salmonella serovars. Also, it is notable that only minimal research has been done on shellfish such as conchs and whelks, which are common in the Caribbean and West Indies. Information on anaerobic bacteria, particularly, non-spore forming bacteria associated with shellfish, in general, is also scanty. This review re-examines this globally important topic based on the recent findings as well as past observations. Strategies for reduction of bacteria in oysters are briefly mentioned because of the fact that oysters are consumed commonly without complete cooking.

  17. AFLP variability, toxin production, and pathogenicity of Alternaria species from Argentinean tomato fruits and puree.

    Science.gov (United States)

    Somma, Stefania; Pose, Graciela; Pardo, Alejandro; Mulè, Giuseppina; Pinto, Virginia Fernandez; Moretti, Antonio; Logrieco, Antonio Francesco

    2011-02-28

    Large amounts of tomato fruits and derived products are produced in Argentina and may be contaminated by Alternaria toxins. Limited information is available on the genetic variability, toxigenicity, and pathogenicity of Alternaria strains occurring on tomato. We analyzed 65 Alternaria strains isolated in Argentina from tomato fruits affected by black mould and from tomato puree, using amplified fragment length polymorphisms (AFLPs) technique. AFLP analysis resolved the set of strains in 3 main clusters (DICE similarity values of 58 and 60%) corresponding to A. alternata/tenuissima (44 strains), A. arborescens (15 strains) and to an unknown group (6 strains). Most of the representative strains, belonging to each AFLP cluster, when cultured on rice, produced tenuazonic acid (up to 46,760 mg/kg), alternariol monomethyl ether (AME, up to 1860 mg/kg), and alternariol (up to 70 mg/kg). The toxin profile related to the strains was not related to any AFLP cluster, except for AME which was produced at lower level by A. arborescens. Most of strains were pathogenic on two types of commonly cultivated tomato fruits. These findings provide new information on the variability within the Alternaria species complex associated with tomato disease. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. The Neglected Intrinsic Resistome of Bacterial Pathogens

    Science.gov (United States)

    Fajardo, Alicia; Martínez-Martín, Nadia; Mercadillo, María; Galán, Juan C.; Ghysels, Bart; Matthijs, Sandra; Cornelis, Pierre; Wiehlmann, Lutz; Tümmler, Burkhard; Baquero, Fernando; Martínez, José L.

    2008-01-01

    Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature. PMID:18286176

  19. The neglected intrinsic resistome of bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Alicia Fajardo

    Full Text Available Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature.

  20. Biological control of necrotrophic plant pathogenic fungi: Tomato ...

    African Journals Online (AJOL)

    However, it was less effective against Phytophthora infestans (64.7 % RGI), Botrytis cinerea (58.3 % RGI), Sclerotinia sclerotiorum (57.4 % RGI) Rhizoctonia solani (42.7 % RGI). When B. subtilis was applied to Tomato field, it exhibited different efficiency in suppressing Fusarium wilt. Time of implementation was critical for ...

  1. Towards allele mining of bacterial wilt disease resistance gene in tomato

    International Nuclear Information System (INIS)

    Galvez, H.F.; Narciso, J.O.; Opina, N.L.; Canama, A.O.; Colle, M.G.; Latiza, M.A.; Caspillo, C.L.; Bituin, J.L.; Frankie, R.B.; Hautea, D.M.

    2005-01-01

    Tomato (Lycopersicon esculentum Mill.) is the most important vegetable commodity of the Philippines. Bacterial wilt caused by Ralstonia solanacearum is one serious constraint in tomato production particularly during off-season planting. A major locus derived from H7996 that confers resistance to bacterial wilt has been mapped in the tomato genome. To validate the biological function of the resistance locus and generate multiple allele -mimics-, targeted mutation was induced in tomato using gamma ray and ethyl methane sulfonate (EMS) mutagens. Suitable mutagen treatment was established by evaluating a wide range of mutagen doses/concentrations for a) percent seed germination, b) reduction in plant height, and c) loss of resistance. Six hundred Gy and 1.0% EMS were identified to generate large M1 families of H7996. From 10,000 initial seeds treated with either gamma ray or EMS, a total of 3,663 M1 plants were generated. M2 seeds were harvested from all surviving M1 plants. Several DNA markers have been resourced and are being developed specific to the bacterial wilt resistant gene. In the large M2 population, of H7996, both the phenotypic manifestation of bacterial wilt susceptibility and nucleotide changes in the resistance locus will be evaluated. Large M3 families for the different allele series of the bacterial wilt resistance gene will be established for future high throughput TILLING (Targeting Induced Local Lesions in Genomes) analysis in the gene region

  2. Imaging O2 changes induced in tomato roots by fungal pathogen

    Science.gov (United States)

    Rubol, S.; Turco, E.; Rodeghiero, M.; Bellin, A.

    2014-12-01

    In the last decade, planar optodes have demonstrated to be a useful non-invasive tool to monitor real time oxygen concentrations in a wide range of applications. However, only limited investigations have been carried out to explore the use of optodes in plant respiration studies. In particular, their use to study plant-pathogen interactions has been not deeply investigated. Here, we present for the first time an in vitro experimental setup capable to depict the dynamical effects of the fungal pathogen Fusarium oxysporum f.sp. lycopersici (Fol) on tomato roots by the use of a recently developed optical non-invasive optode oxygen sensor (Visisens, Presens, Germany). Fol is a soil-borne pathogen and the causal agent of wilt in tomato plants, a destructive worldwide disease. The interaction Fol-tomato is widely accepted as a model system in plant pathology. In this work, oxygen concentrations are monitored continuously in time and considered a proxy for root respiration and metabolic activity. The experimental procedure reveals three different dynamic stages: 1) a uniform oxygen consumption in tomato roots earlier before pathogen colonization, 2) a progressive decrease in the oxygen concentration indicating a high metabolic activity as soon as the roots were surrounded and colonized by the fungal mycelium, and 3) absence of root respiration, as a consequence of root death. Our results suggest the ability of the fungal mycelium to move preferentially towards and along the root as a consequence of the recognition event.

  3. Secondary metabolism and biotrophic lifestyle in the tomato pathogen Cladosporium fulvum

    NARCIS (Netherlands)

    Collemare, J.; Griffiths, S.A.; Iida, Y.; Karimi Jashni, M.; Battaglia, E.; Cox, R.J.; Wit, de P.J.G.M.

    2014-01-01

    Cladosporium fulvum is a biotrophic fungal pathogen that causes leaf mould of tomato. Analysis of its genome suggested a high potential for production of secondary metabolites (SM), which might be harmful to plants and animals. Here, we have analysed in detail the predicted SM gene clusters of C.

  4. Occurrence of Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker of tomato, in Syria

    Directory of Open Access Journals (Sweden)

    Radwan FTAYEH

    2010-09-01

    Full Text Available Several surveys were carried out to evaluate the occurrence of bacterial canker of tomato caused by Clavibacter michiganensis subsp. michiganensis (Cmm in Syria, especially in the North-West provinces Latakiaand Tartous. The surveys revealed typical disease symptoms in greenhouses where the tomato cvs. Dima, Huda and Astona were grown, such as dark brown to black lesions on the leaf margins, wilting of whole plants, stunting, and vascular discoloration. The disease incidence in such greenhouses was 15% in the spring of 2007, and up to 70% by the end of July. Ten isolates obtained from diseased plants at different locations in these two provinces were identified as Clavibacter michiganensis subsp. michiganensis using classical microbiological tests as well as PCR. This is the first detailed proof of the occurrence of bacterial canker of tomato in Syria.

  5. The potential of endomycorrhizal fungi in controlling tomato bacterial ...

    African Journals Online (AJOL)

    user

    2012-08-21

    Aug 21, 2012 ... The main objective of the present work was to determine the efficiency of a ... Streaming test. An infected plant was tested by taking sections from the lower part of tomato stem and placed in a test tube filled with distilled water. The presence of ... from the media was taken indicating that R. solanacearum was.

  6. Drought Impact on the Soilborne Fungal Pathogen of Tomato: Fusarium Oxysporum f. sp. Lycopersici Race 3

    Science.gov (United States)

    Raju, T.

    2016-12-01

    This paper reviews the drought impact on fungal pathogen of tomato. It presents the 11 Main Procedures used to conduct the experiments and discusses materials used. The 11 procedures are: Gather All the Soils, Sterilize the Soils Using Auto-Clave, Water Retention Test Using Auto-Clave, Cultivate Pathogen, Grow Tomato Plant, Count Pathogenic Cells, Inoculate the Pathogen, Conduct Root Dip, Grow Positive and Negative Samples, Test for Fusarium, and the Soil Separation Experiment with Pathogenic Soil. Experiments conducted on 6 Main Soils used in farming throughout California. The Yolo Series, Whiterock Series, Euic Soil, Potting Soil, Blacklock Series, and Henneke Series. The 6 Soils include amounts of clay, silt, sand, loam, and humus. It was crucial that these soils include these properties because deriving from last year's research I found that these particles in the soil has a role in the growth of the plant. Next, I tested the dry/wet weight of the soils, as this gave me a good estimate of how much water the soils can retain. This is very important because I found a direct correlation between the soil that retained the most amount of water and the soil that had the least harms done. Next, the other labs were completed to cultivate, inoculate, and test the pathogens in the soil, now these steps must be carried out with accuracy and precision because pathogens are a biological agent that causes disease or illness to its host, and if even 0.100 mL is changed in the pathogenic level it can make a large difference. Later, after I finished conducting the root dip, and raising the tomato plants. I counted the Fusarium count in the soil and plated the samples, where I was able to find the results on how much harm the pathogen had on the plant. In each of the 90 reps. the Fusarium (soilborne pathogen) decreased a little, which factors in the transfer from Potato Dextrose Agar Petri Dish to the Soils. After, this transfer the pathogen decreased and never increased, but

  7. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    OpenAIRE

    Che, Dongsheng; Hasan, Mohammad Shabbir; Chen, Bernard

    2014-01-01

    High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs). PAI...

  8. Diagnostics and Resistance Profiling of Bacterial Pathogens.

    Science.gov (United States)

    Hornischer, Klaus; Häußler, Susanne

    Worldwide infectious disease is one of the leading causes of death. Despite improvements in technology and healthcare services, morbidity and mortality due to infections have remained unchanged over the past few decades. The high and increasing rate of antibiotic resistance is further aggravating the situation. Growing resistance hampers the use of conventional antibiotics, and substantial higher mortality rates are reported in patients given ineffective empiric therapy mainly due to resistance to the agents used. These infections cause suffering, incapacity, and death and impose an enormous financial burden on both healthcare systems and on society in general. The accelerating development of multidrug resistance is one of the greatest diagnostic and therapeutic challenges to modern medicine. The lack of new antibiotic options underscores the need for optimization of current diagnostics, therapies, and prevention of the spread of multidrug-resistant organisms. The so-called -omics technologies (genomics, transcriptomics, proteomics, and metabolomics) have yielded large-scale datasets that advanced the search for biomarkers of infectious diseases in the last decade. One can imagine that in the future the implementation of biomarker-driven molecular test systems will transform diagnostics of infectious diseases and will significantly accelerate the identification of the bacterial pathogens at the infected host site. Furthermore, molecular tests based on the identification of markers of antibiotic resistance will dramatically change resistance profiling. The replacement of culturing methods by molecular test systems for early diagnosis will provide the basis not only for a prompt and targeted therapy, but also for a much more effective stewardship of antibiotic agents and a reduction of the spread of multidrug resistance as well as the appearance of new antibiotic resistances.

  9. Evolutionary biology of bacterial and fungal pathogens

    National Research Council Canada - National Science Library

    Cassell, Gail H; Gutierrez-Fuentes, Jose A; Barquero, Fernando; Nombela, Cesar

    2008-01-01

    ... and Evolutionary Dynamics of Pathogens * 21 Keith A. Crandall and Marcos Pérez-Losada II. Evolutionary Genetics of Microbial Pathogens 4. Environmental and Social Influences on Infectious Disea...

  10. Models of Caenorhabditis elegans infection by bacterial and fungal pathogens.

    Science.gov (United States)

    Powell, Jennifer R; Ausubel, Frederick M

    2008-01-01

    The nematode Caenorhabditis elegans is a simple model host for studying the relationship between the animal innate immune system and a variety of bacterial and fungal pathogens. Extensive genetic and molecular tools are available in C. elegans, facilitating an in-depth analysis of host defense factors and pathogen virulence factors. Many of these factors are conserved in insects and mammals, indicating the relevance of the nematode model to the vertebrate innate immune response. Here, we describe pathogen assays for a selection of the most commonly studied bacterial and fungal pathogens using the C. elegans model system.

  11. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    Directory of Open Access Journals (Sweden)

    Dongsheng Che

    2014-01-01

    Full Text Available High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs. PAIs have some detectable properties, such as having different genomic signatures than the rest of the host genomes, and containing mobility genes so that they can be integrated into the host genome. In this review, we will discuss various pathogenicity island-associated features and current computational approaches for the identification of PAIs. Existing pathogenicity island databases and related computational resources will also be discussed, so that researchers may find it to be useful for the studies of bacterial evolution and pathogenicity mechanisms.

  12. Sources of resistance to races R0 and R1 of Pseudomonas syringae PV. tomato - agent of bacterial speck on tomato

    Directory of Open Access Journals (Sweden)

    Ganeva Daniela

    2017-01-01

    Full Text Available Tomato breeding lines with fruit colour different from the traditional red colour were studied in order to search for sources of resistance to races R0 and R1 of Pseudomonas syringae pv. tomato. As a result of selection of healthy plants with hypersensitive response (HR, the resistance was stabilized and perspective lines gene-carriers of resistance to bacterial speck were chosen. Lines L1078 and L1083 with brown-red (black coloured fruits and line L1130 with purple-red fruits possess a complex resistance to races R0 and R1. It was established that two of the lines with rose-coloured tomato fruits (L1088 and L584 were resistant to race 1 of P. syringae pv. tomato. These lines possessed valuable economic and morphological characters and they could be used in combinative and heterosis breeding for development of resistance to bacterial speck varieties.

  13. Antibiotic resistance in bacterial pathogens causing meningitis in ...

    African Journals Online (AJOL)

    Antibiotic resistance in bacterial pathogens causing meningitis in children at Harare Central Hospital, Zimbabwe. M Gudza-Mugabe, R.T. Mavenyengwa, M.P. Mapingure, S Mtapuri-Zinyowera, A Tarupiwa, V.J. Robertson ...

  14. Bacterial pathogens associated with infected wounds in Ogun State ...

    African Journals Online (AJOL)

    OSUTH) between August 1999 and July 2000 in the Orthopaedics, Obstetrics and Gynaecological units to identify the bacterial pathogens associated with infected wounds as well as their antibiotic sensitivity profile. A total of 1670 patients were ...

  15. Endophytic Bacteria Suppress Bacterial Wilt of Tomato Caused by Ralstonia solanacearum and Activate Defense-related Metabolites

    Directory of Open Access Journals (Sweden)

    Fahime Safdarpour

    2017-12-01

    Full Text Available Introduction: Phytopathogenic microorganisms affect plant health and burden a major threat to food production and ecosystem stability. Increasing the use of chemical pesticides for plant diseases control causes several negative effects on human and environment health. Furthermore, increasing public awareness about the side effects of them led to a research to find alternatives for these products. One of the alternative methods is bio-control utilizing plant associated antagonistic microorganisms. Materials and methods: In this study, 80 endophytic bacteria were isolated from tomato tissues. Their antagonistic activity screened based on agar diffusion test, against tomato bacterial wilt disease (Ralstonia solanacearum. They were identified based on the morphological, biochemical properties and 16s rRNA sequence analyses. These strains were evaluated in greenhouse and tested for their ability to induce the production of defense-related enzymes in plants e.g. Peroxidase (PO, polyphenoloxidase (PPO and phenolics based on spectrophotometer method. Results: Results showed FS67, FS167 and FS184 strains had maximum inhibition zone forming. They identified as Pseudomonas mossellii, P. fuorescence and P. brassicacearum respectively. FS67 and FS167 strains significantly reduced disease in greenhouse. There was a significant increase in the activity of PO, PPO and phenolics in tomato plants treated with FS67, FS167 and pathogen. Discussion and conclusion: The present study has shown that P. mosselli and P. fuorescence might have the potential to control R. solanacearum. However, the good results obtained in vitro cannot be gained the same as those in greenhouse or field conditions. So, further experiments are needed to determine the effectiveness of these isolates under field conditions.This work support the view that increased defense enzymes activities could be involved, at least in part, in the beneficial effects of endophytic bacteria on plants growth

  16. Antibiotic Sensitivity of Bacterial Pathogens in Urinary Tract ...

    African Journals Online (AJOL)

    Antibiotic Sensitivity of Bacterial Pathogens in Urinary Tract Infections at Muhimbili National Hospital, Dar es Salaam, Tanzania. ... Prevalence and sensitivity trends of urinary tract bacterial isolates were determined through a cross sectional retrospective study at Muhimbili National Hospital in Dar es Salaam. Four hundred ...

  17. Methods to classify bacterial pathogens in cystic fibrosis

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Nielsen, Xiaohui Chen; Johansen, Ulla

    2011-01-01

    Many bacteria can be detected in CF sputum, pathogenic and commensal. Modified Koch's criteria for identification of established and emerging CF pathogens are therefore described. Methods are described to isolate bacteria and to detect bacterial biofilms in sputum or lung tissue from CF patients ...

  18. Occurrence Of Foodborne Bacterial Pathogens In Smoked Fish At ...

    African Journals Online (AJOL)

    Sixty five (65) smoked fish samples (30 catfish and 35 Tilapia) were obtained form three retail market locations in Jos South, Nigeria, and screened for foodborne bacterial pathogens. Potential human pathogens were isolated from all the samples studied through culture, growth characteristics, morphological, physiological ...

  19. Antibacterial activity of essential oils on Xanthomonas vesicatoria and control of bacterial spot in tomato

    Directory of Open Access Journals (Sweden)

    Gilvaine Ciavareli Lucas

    2012-03-01

    Full Text Available The objective of this work was to evaluate the effects of plant essential oils (EOs on the growth of Xanthomonas vesicatoria, on bacterial morphology and ultrastructure, and on the severity of tomato bacterial spot. EOs from citronella, clove, cinnamon, lemongrass, eucalyptus, thyme, and tea tree were evaluated in vitro at concentrations of 0.1, 1.0, 10, and 100% in 1.0% powdered milk. The effect of EOs, at 0.1%, on the severity of tomato bacterial spot was evaluated in tomato seedlings under greenhouse conditions. The effects of citronella, lemongrass, clove, and tea tree EOs, at 0.1%, on X. vesicatoria cells were evaluated by transmission electron microscopy. All EOs showed direct toxic effect on the bacteria at a 10%-concentration in vitro. Under greenhouse conditions, the EOs of clove, citronella, tea tree, and lemongrass reduced disease severity. EOs of clove and tea tree, and streptomycin sulfate promoted loss of electron-dense material and alterations in the cytoplasm, whereas EO of tea tree promoted cytoplasm vacuolation, and those of citronella, lemongrass, clove, and tea tree caused damage to the bacterial cell wall. The EOs at a concentration of 0.1% reduce the severity of the disease.

  20. Bacterial Metabolism Shapes the Host-Pathogen Interface.

    Science.gov (United States)

    Passalacqua, Karla D; Charbonneau, Marie-Eve; O'Riordan, Mary X D

    2016-06-01

    Bacterial pathogens have evolved to exploit humans as a rich source of nutrients to support survival and replication. The pathways of bacterial metabolism that permit successful colonization are surprisingly varied and highlight remarkable metabolic flexibility. The constraints and immune pressures of distinct niches within the human body set the stage for understanding the mechanisms by which bacteria acquire critical nutrients. In this article we discuss how different bacterial pathogens carry out carbon and energy metabolism in the host and how they obtain or use key nutrients for replication and immune evasion.

  1. Bacterial metabolism shapes the host:pathogen interface

    Science.gov (United States)

    Passalacqua, Karla D.; Charbonneau, Marie-Eve; O'Riordan, Mary X.D.

    2016-01-01

    Summary Bacterial pathogens have evolved to exploit humans as a rich source of nutrients to support survival and replication. The pathways of bacterial metabolism that permit successful colonization are surprisingly varied and highlight remarkable metabolic flexibility. The constraints and immune pressures of distinct niches within the human body set the stage for understanding the mechanisms by which bacteria acquire critical nutrients. Here we discuss how different bacterial pathogens carry out carbon and energy metabolism in the host, and how they obtain or use key nutrients for replication and immune evasion. PMID:27337445

  2. Mutation breeding for tomato bacterial with disease resistance through in vitro techniques

    International Nuclear Information System (INIS)

    Keoboonrueng, S.; Charaensatapon, R.; Panichsukpatana, C.; Jatisation, J.

    1994-01-01

    Cotyledons of half month and one month-old seedlings of tomato varieties Sida, SVRDC 4, Sidatip 2 and VF 137 irradiated with gamma rays at the dose of 10 Gy were cultured on most suitable medium found, MS supplemented with 0.01 mg/1 NAA and 2.0 mg/1 BAP. Sometimes calli and multiple shoots derived from normal seedlings were irradiated with gamma rays at the doses of 5 and 8 Gy, respectively. Plantlets from in vitro culture were screened in the greenhouse by soaking roots in bacterial suspension at transplanting time or by pouring bacterial suspension on injured roots at 2-3 wk. after transplant. The concentration of bacterial suspension was 10 5 -10 7 cells/ml. Total of 2541 tomato plantlets were screened and only 11 plants survived. They were, 5 plants from non-irradiated Sida, 1 and 2 plants from 5 and 10 Gy Sida, respectively, 2 plants from 5 Gy Sidatip 2 and single plant from non-irradiated VF 137. Most of the surviving plants were susceptible to tomato yellow leaf curl virus and only fruits from one Sida plant irradiated with 10 Gy could be harvested. Plants from these seeds will be further selected

  3. Common Bacterial Pathogens and their Antibiotic Sensitivity

    African Journals Online (AJOL)

    these three drugs can be used in treating most from this study suggest that these three drugs can be used in treating most bacterial infections. This would be particularly useful in health set-ups where culturing and sensitivity testing is impossible, although the availability and cost effectiveness of these antibiotics is in ...

  4. Cytosolic Access of Intracellular Bacterial Pathogens: The Shigella Paradigm.

    Science.gov (United States)

    Mellouk, Nora; Enninga, Jost

    2016-01-01

    Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.

  5. Cytosolic access of intracellular bacterial pathogens: the Shigella paradigm

    Directory of Open Access Journals (Sweden)

    Nora eMellouk

    2016-04-01

    Full Text Available Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.

  6. Residual polysaccharides from fungi reduce the bacterial spot in tomato plants

    Directory of Open Access Journals (Sweden)

    Tarsis Aguiar

    2018-03-01

    Full Text Available Abstract Polysaccharides from fungal wastes were partially characterized and evaluated for their protective effects against bacterial spot caused by Xanthomonas gardneri on four tomato cultivars: Santa Cruz Kada, Natália, BRS Sena and Forty. The polysaccharides were extracted from spent mushroom substrate of Pleurotus ostreatus, residual brewery yeast (Saccharomyces cerevisiae, and basidiocarps discarded from Lentinula edodes production. These polysaccharides were characterized for total carbohydrates, phenolics and proteins content, pH, scatter intensity, conductivity, Zeta potential, DPPH scavenging assay and infrared spectroscopy. The effects of time interval between treatment and inoculation (4 or 7 days and polysaccharide concentrations (0.5 or 1.5 mg.mL–1 were assessed for disease severity using a susceptible tomato cultivar. The polysaccharide action mode was investigated by determining the activity of peroxidases and phenylalanine ammonialyase and by quantifying flavonoids and total phenolics in the plants treated and challenged with X. gardneri. The polysaccharides obtained from Lentinula edodes (PSHII, Saccharomyces cerevisiae (PRC and Pleurotus ostreatus (PSPO (1.5 mg.mL-1 reduced bacterial spot severity by 50% on tomato cotyledons, leaflets and five-leaf plants. Furthermore, PRC and PSHII (1.5 mg.mL–1 could decrease disease severity in all tested cultivars. PSHII, the most effective, did not cause change in phenylalanine ammonia-lyase activity or flavonoid content on the cultivars Kada and Natália. However, an increase in peroxidase activity and total phenol content on cv. Kada was noted. The polysaccharides obtained from food industry wastes could provide protection against bacterial spot on tomato cultivars by inducing defense mechanisms and can be useful in formulating products with phytosanitary potential.

  7. Occurrence of antimicrobial resistance among bacterial pathogens

    OpenAIRE

    Hendriksen, Rene S.; Mevius, Dik J.; Schroeter, Andreas; Teale, Christopher; Jouy, Eric; Butaye, Patrick; Franco, Alessia; Utinane, Andra; Amado, Alice; Moreno, Miguel; Greko, Christina; Stärk, Katharina D.C.; Berghold, Christian; Myllyniemi, Anna-Liisa; Hoszowski, Andrzej

    2008-01-01

    Background: The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003–05. The aim of this project was to establish a program for the continuous monitoring of antimicrobial susceptibility of pathogenic and indicator bacteria from food animals using validated and harmonised methodologies. In this report the first data on the occurrence of antimicrobial resistance among bacteria cau...

  8. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms.

    Science.gov (United States)

    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.

  9. Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

    Science.gov (United States)

    Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6) colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized by

  10. Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

    Directory of Open Access Journals (Sweden)

    Bhabesh Dutta

    Full Text Available The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6 colony forming units (CFUs/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion. Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating, respectively and they were not significantly different (P = 0.67. The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03. None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be

  11. Metabolic host responses to infection by intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Wolfgang eEisenreich

    2013-07-01

    Full Text Available The interaction of bacterial pathogens with mammalian hosts leads to a variety of physiological responses of the interacting partners aimed at an adaptation to the new situation. These responses include multiple metabolic changes in the affected host cells which are most obvious when the pathogen replicates within host cells as in case of intracellular bacterial pathogens. While the pathogen tries to deprive nutrients from the host cell, the host cell in return takes various metabolic countermeasures against the nutrient theft. During this conflicting interaction, the pathogen triggers metabolic host cell responses by means of common cell envelope components and specific virulence-associated factors. These host reactions generally promote replication of the pathogen. There is growing evidence that pathogen-specific factors may interfere in different ways with the complex regulatory network that controls the carbon and nitrogen metabolism of mammalian cells. The host cell defence answers include general metabolic reactions, like the generation of oxygen- and/or nitrogen-reactive species, and more specific measures aimed to prevent access to essential nutrients for the respective pathogen. Accurate results on metabolic host cell responses are often hampered by the use of cancer cell lines that already exhibit various de-regulated reactions in the primary carbon metabolism. Hence, there is an urgent need for cellular models that more closely reflect the in vivo infection conditions. The exact knowledge of the metabolic host cell responses may provide new interesting concepts for antibacterial therapies.

  12. Bacterial pathogens in a reactor cooling reservoir

    International Nuclear Information System (INIS)

    Kasweck, K.L.; Fliermans, C.B.

    1978-01-01

    The results of the sampling in both Par Pond and Clark Hill Reservoir are given. The frequency of isolation is a qualitative parameter which indicates how often the specified bacterium was isolated from each habitat. Initial scoping experiments demonstrated that a wider variety of pathogenic bacteria occur in Par Pond than in Clark Hill Reservoir. Such findings are interesting because Par Pond does not receive any human wastes directly, yet bacteria generally associated with human wastes are more frequently isolated from Par Pond. Previous studies have demonstrated that certain non-spore-forming enteric bacteria do not survive the intense heat associated with the cooling water when the reactor is operating. However, even when the reactor is not operating, cooling water, consisting of 10% makeup water from Savannah River, continues to flow into Par Pond. This flow provides a source of bacteria which inoculate Par Pond. Once the reactor is again operating, these same bacteria appear to be able to survive and grow within the Par Pond system. Thus, Par Pond and the associated lakes and canals of the Par Pond system provide a pool of pathogens that normally would not survive in natural waters

  13. Kynetic resazurin assay (KRA) for bacterial quantification of foodborne pathogens

    Science.gov (United States)

    Arenas, Yaxal; Mandel, Arkady; Lilge, Lothar

    2012-03-01

    Fast detection of bacterial concentrations is important for the food industry and for healthcare. Early detection of infections and appropriate treatment is essential since, the delay of treatments for bacterial infections tends to be associated with higher mortality rates. In the food industry and in healthcare, standard procedures require the count of colony-forming units in order to quantify bacterial concentrations, however, this method is time consuming and reports require three days to be completed. An alternative is metabolic-colorimetric assays which provide time efficient in vitro bacterial concentrations. A colorimetric assay based on Resazurin was developed as a time kinetic assay (KRA) suitable for bacterial concentration measurements. An optimization was performed by finding excitation and emission wavelengths for fluorescent acquisition. A comparison of two non-related bacteria, foodborne pathogens Escherichia coli and Listeria monocytogenes, was performed in 96 well plates. A metabolic and clonogenic dependence was established for fluorescent kinetic signals.

  14. Characterization and evaluation of Bacillus amyloliquefaciens strain WF02 regarding its biocontrol activities and genetic responses against bacterial wilt in two different resistant tomato cultivars.

    Science.gov (United States)

    Huang, Chu-Ning; Lin, Chan-Pin; Hsieh, Feng-Chia; Lee, Sook-Kuan; Cheng, Kuan-Chen; Liu, Chi-Te

    2016-11-01

    Bacillus amyloliquefaciens strain WF02, isolated from soil collected at Wufeng Mountain, Taiwan, has siderophore-producing ability and in vitro antagonistic activity against bacterial wilt pathogen. To determine the impact of plant genotype on biocontrol effectiveness, we treated soil with this strain before infecting susceptible (L390) and moderately resistant (Micro-Tom) tomato cultivars with Ralstonia solanacearum strain Pss4. We also compared the efficacy of this strain with that of commercial Bacillus subtilis strain Y1336. Strain WF02 provided longer lasting protection against R. solanacearum than did strain Y1336 and controlled the development of wilt in both cultivars. To elucidate the genetic responses in these plants under WF02 treatment, we analyzed the temporal expression of defense-related genes in leaves. The salicylic acid pathway-related genes phenylalanine ammonia-lyase and pathogenesis-related protein 1a were up-regulated in both cultivars, whereas expression of the jasmonic acid pathway-related gene lipoxygenase was only elevated in the susceptible tomato cultivar (L390). These results suggest that WF02 can provide protection against bacterial wilt in tomato cultivars with different levels of disease resistance via direct and indirect modes of action.

  15. [Rapid identification of meningitis due to bacterial pathogens].

    Science.gov (United States)

    Ubukata, Kimiko

    2013-01-01

    We constructed a new real-time PCR method to detect causative pathogens in cerebrospinal fluid (CSF) from patient due to bacterial meningitis. The eight pathogens targeted in the PCR are Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus agalactiae, Staphylococcus aurues, Neisseria meningitides, Listeria monocytogenes, Esherichia coli, and Mycoplasma pneumoniae. The total time from DNA extraction from CSF to PCR analysis was 1.5 hour. The pathogens were detected in 72% of the CSF samples (n=115) by real-time PCR, but in only 48% by culture, although the microorganisms were completely concordant. The detection rate of pathogens with PCR was significantly better than that with cultures in patients with antibiotic administration.In conclusion, detection with real-time PCR is useful for rapidly identifying the causative pathogens of meningitis and for examining the clinical course of chemotherapy.

  16. Xanthomonads and other yellow-pigmented, Xanthomonas-like bacteria associated with tomato seeds in Tanzania

    DEFF Research Database (Denmark)

    Mbega, Ernest Rashid; Wulff, Ednar Gadelha; Mabagala, R.B.

    2012-01-01

    Tomato (Solanum lycopersicum L.) seeds habour unique bacterial community that can be pathogenic or beneficial to their host. Xanthomonas causing bacterial leaf spot (BLSX) on tomato and other yellow-pigmented xanthomonads-like bacteria (XLB) that closely resemble BLSX were obtained from tomato...... of Xanthomonas campestris pv. malvacearum, were pathogenic on tomato and pepper plants. Strains identified by Biolog as Sphingomonas sanguinis and Sphingomonas terrae also incited black rot symptoms on pepper leaves. However, bacterial strains belonging to the genus Stenotrophomonas, Chryseobacterium, Pantoea...... and Flavobacterium were not pathogenic on tomato and pepper. Phylogenetic analysis showed that strains of the genus Xanthomonas are more closely related to Stenotrophomonas and Pantoea compared to the other bacterial genera found in tomato seeds....

  17. Characterisation of bacterial brown spot pathogen from dry bean ...

    African Journals Online (AJOL)

    Pseudomonas syringae pv. syringae (Pss) causes bacterial brown spot (BBS) of beans (Phaseolus vulgaris L.), with yield losses of up to 55% in South Africa. Pss has a wide host range and for many of these, the pathogen has been biochemically and genetically characterised. However, few studies have been conducted on ...

  18. Mobile phone as potential reservoirs of bacterial pathogens ...

    African Journals Online (AJOL)

    Mobile phones are increasingly used by professionals, university staffs and health care personnel for communication. These can harbor various potential pathogens. This study evaluates and identifies the bacterial contamination rate of mobile phones in the university setting that are in frequent contact with faculty members, ...

  19. Bacterial Pathogens Associated with Tap and Well Waters in Lagos ...

    African Journals Online (AJOL)

    Results: Our finding revealed that all the well waters from the locations under study were contaminated with one or more of the following bacterial pathogens Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Enterobacter aerogenes, Shigella dysenteriae, Proteus vulgaris and Pseudomonas aeruginosa, with E coli ...

  20. Bacterial pathogens associated with secondary peritonitis in Lagos ...

    African Journals Online (AJOL)

    Secondary peritonitis is a common and serious form of intra-abdominal infection, often associated with high morbidity and mortality. The overall patient outcome has not markedly improved in spite of advances in patient management. There is therefore need to study the pattern of bacterial pathogens associated with ...

  1. Bithionol blocks pathogenicity of bacterial toxins, ricin, and Zika virus

    Science.gov (United States)

    Disease pathways form overlapping networks, and hub proteins represent attractive targets for broad-spectrum drugs. Using bacterial toxins as a proof of concept, we describe a new approach of discovering broad-spectrum therapies capable of inhibiting host proteins that mediate multiple pathogenic pa...

  2. Antibiogram of bacterial pathogens isolated from subclinical mastitis ...

    African Journals Online (AJOL)

    The present investigation was carried out to study the prevalence of bacterial pathogens responsible for subclinical mastitis in cattle and their antibiogram pattern to selected antibiotics. The study was carried out on lactating cows in small holder dairy farms in and around Kombolcha, South Wollo, Amhara region, Ethiopia.

  3. pathogenic intestinal parasites and bacterial agents in solid wastes

    African Journals Online (AJOL)

    2003-03-01

    Mar 1, 2003 ... INTRODUCTION. Refuse, soil, animal waste and sewage sludge are common sources of manure, used to fertilize agriculture. fie1ds(1-3). Studies have revealed the incidence and distribution of many pathogenic intestinal parasites and bacterial agents from refuse which infect both man and animals(4-6).

  4. Menaquinone analogs inhibit growth of bacterial pathogens.

    Science.gov (United States)

    Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R

    2013-11-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.

  5. Bacterial siderophores efficiently provide iron to iron-starved tomato plants in hydroponics culture.

    Science.gov (United States)

    Radzki, W; Gutierrez Mañero, F J; Algar, E; Lucas García, J A; García-Villaraco, A; Ramos Solano, B

    2013-09-01

    Iron is one of the essential elements for a proper plant development. Providing plants with an accessible form of iron is crucial when it is scant or unavailable in soils. Chemical chelates are the only current alternative and are highly stable in soils, therefore, posing a threat to drinking water. The aim of this investigation was to quantify siderophores produced by two bacterial strains and to determine if these bacterial siderophores would palliate chlorotic symptoms of iron-starved tomato plants. For this purpose, siderophore production in MM9 medium by two selected bacterial strains was quantified, and the best was used for biological assay. Bacterial culture media free of bacteria (S) and with bacterial cells (BS), both supplemented with Fe were delivered to 12-week-old plants grown under iron starvation in hydroponic conditions; controls with full Hoagland solution, iron-free Hoagland solution and water were also conducted. Treatments were applied twice along the experiment, with a week in between. At harvest, plant yield, chlorophyll content and nutritional status in leaves were measured. Both the bacterial siderophore treatments significantly increased plant yield, chlorophyll and iron content over the positive controls with full Hoagland solution, indicating that siderophores are effective in providing Fe to the plant, either with or without the presence of bacteria. In summary, siderophores from strain Chryseobacterium C138 are effective in supplying Fe to iron-starved tomato plants by the roots, either with or without the presence of bacteria. Based on the amount of siderophores produced, an effective and economically feasible organic Fe chelator could be developed.

  6. Methods to classify bacterial pathogens in cystic fibrosis

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Nielsen, Xiaohui Chen; Johansen, Ulla

    2011-01-01

    Many bacteria can be detected in CF sputum, pathogenic and commensal. Modified Koch's criteria for identification of established and emerging CF pathogens are therefore described. Methods are described to isolate bacteria and to detect bacterial biofilms in sputum or lung tissue from CF patients...... by means of conventional culturing and staining techniques and by the PNA FISH technique. Additionally, the confocal scanning laser microscopy technique is described for studying biofilms in vitro in a flow cell system. The recA-gene PCR and the RFLP-based identification methods are described...... for identification of isolates from the Burkholderia complex to the species level. DNA typing by PFGE, which can be used for any bacterial pathogen, is described as it is employed for Pseudomonas aeruginosa. A commercially available ELISA method is described for measuring IgG antibodies against P. aeruginosa in CF...

  7. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara

    2011-11-03

    Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

  8. Plant growth-promoting endophytic bacteria versus pathogenic infections: an example of Bacillus amyloliquefaciens RWL-1 and Fusarium oxysporum f. sp. lycopersici in tomato

    Directory of Open Access Journals (Sweden)

    Raheem Shahzad

    2017-03-01

    Full Text Available Fungal pathogenic attacks are one of the major threats to the growth and productivity of crop plants. Currently, instead of synthetic fungicides, the use of plant growth-promoting bacterial endophytes has been considered intriguingly eco-friendly in nature. Here, we aimed to investigate the in vitro and in vivo antagonistic approach by using seed-borne endophytic Bacillus amyloliquefaciens RWL-1 against pathogenic Fusarium oxysporum f. sp. lycopersici. The results revealed significant suppression of pathogenic fungal growth by Bacillus amyloliquefaciens in vitro. Further to this, we inoculated tomato plants with RWL-1 and F. oxysporum f. sp. lycopersici in the root zone. The results showed that the growth attributes and biomass were significantly enhanced by endophytic-inoculation during disease incidence as compared to F. oxysporum f. sp. lycopersici infected plants. Under pathogenic infection, the RWL-1-applied plants showed increased amino acid metabolism of cell wall related (e.g., aspartic acid, glutamic acid, serine (Ser, and proline (Pro as compared to diseased plants. In case of endogenous phytohormones, significantly lower amount of jasmonic acid (JA and higher amount of salicylic acid (SA contents was recorded in RWL-1-treated diseased plants. The phytohormones regulation in disease incidences might be correlated with the ability of RWL-1 to produce organic acids (e.g., succinic acid, acetic acid, propionic acid, and citric acid during the inoculation and infection of tomato plants. The current findings suggest that RWL-1 inoculation promoted and rescued plant growth by modulating defense hormones and regulating amino acids. This suggests that bacterial endophytes could be used for possible control of F. oxysporum f. sp. lycopersici in an eco-friendly way.

  9. Plant growth-promoting endophytic bacteria versus pathogenic infections: an example of Bacillus amyloliquefaciens RWL-1 and Fusarium oxysporum f. sp. lycopersici in tomato

    Science.gov (United States)

    Shahzad, Raheem; Khan, Abdul Latif; Bilal, Saqib

    2017-01-01

    Fungal pathogenic attacks are one of the major threats to the growth and productivity of crop plants. Currently, instead of synthetic fungicides, the use of plant growth-promoting bacterial endophytes has been considered intriguingly eco-friendly in nature. Here, we aimed to investigate the in vitro and in vivo antagonistic approach by using seed-borne endophytic Bacillus amyloliquefaciens RWL-1 against pathogenic Fusarium oxysporum f. sp. lycopersici. The results revealed significant suppression of pathogenic fungal growth by Bacillus amyloliquefaciens in vitro. Further to this, we inoculated tomato plants with RWL-1 and F. oxysporum f. sp. lycopersici in the root zone. The results showed that the growth attributes and biomass were significantly enhanced by endophytic-inoculation during disease incidence as compared to F. oxysporum f. sp. lycopersici infected plants. Under pathogenic infection, the RWL-1-applied plants showed increased amino acid metabolism of cell wall related (e.g., aspartic acid, glutamic acid, serine (Ser), and proline (Pro)) as compared to diseased plants. In case of endogenous phytohormones, significantly lower amount of jasmonic acid (JA) and higher amount of salicylic acid (SA) contents was recorded in RWL-1-treated diseased plants. The phytohormones regulation in disease incidences might be correlated with the ability of RWL-1 to produce organic acids (e.g., succinic acid, acetic acid, propionic acid, and citric acid) during the inoculation and infection of tomato plants. The current findings suggest that RWL-1 inoculation promoted and rescued plant growth by modulating defense hormones and regulating amino acids. This suggests that bacterial endophytes could be used for possible control of F. oxysporum f. sp. lycopersici in an eco-friendly way. PMID:28321368

  10. Plant growth-promoting endophytic bacteria versus pathogenic infections: an example ofBacillus amyloliquefaciensRWL-1 andFusarium oxysporumf. sp.lycopersiciin tomato.

    Science.gov (United States)

    Shahzad, Raheem; Khan, Abdul Latif; Bilal, Saqib; Asaf, Sajjad; Lee, In-Jung

    2017-01-01

    Fungal pathogenic attacks are one of the major threats to the growth and productivity of crop plants. Currently, instead of synthetic fungicides, the use of plant growth-promoting bacterial endophytes has been considered intriguingly eco-friendly in nature. Here, we aimed to investigate the in vitro and in vivo antagonistic approach by using seed-borne endophytic Bacillus amyloliquefaciens RWL-1 against pathogenic Fusarium oxysporum f. sp. lycopersici . The results revealed significant suppression of pathogenic fungal growth by Bacillus amyloliquefaciens in vitro. Further to this, we inoculated tomato plants with RWL-1 and F. oxysporum f. sp. lycopersici in the root zone. The results showed that the growth attributes and biomass were significantly enhanced by endophytic-inoculation during disease incidence as compared to F. oxysporum f. sp. lycopersici infected plants. Under pathogenic infection, the RWL-1-applied plants showed increased amino acid metabolism of cell wall related (e.g., aspartic acid, glutamic acid, serine (Ser), and proline (Pro)) as compared to diseased plants. In case of endogenous phytohormones, significantly lower amount of jasmonic acid (JA) and higher amount of salicylic acid (SA) contents was recorded in RWL-1-treated diseased plants. The phytohormones regulation in disease incidences might be correlated with the ability of RWL-1 to produce organic acids (e.g., succinic acid, acetic acid, propionic acid, and citric acid) during the inoculation and infection of tomato plants. The current findings suggest that RWL-1 inoculation promoted and rescued plant growth by modulating defense hormones and regulating amino acids. This suggests that bacterial endophytes could be used for possible control of F. oxysporum f. sp. lycopersici in an eco-friendly way.

  11. Application of cellular breeding method to assess the quality of tomato varieties (Lycopersicon esculentum Mill. and their resistance to bacterial diseases’ agents

    Directory of Open Access Journals (Sweden)

    Ю. В. Коломієць

    2015-12-01

    Full Text Available Purpose. Assessing under in vitro conditions the degree of resistance to agents of bacterial diseases of tomato varie­ties which are included into the State Register of plant varieties suitable for dissemination in Ukraine in 2015. Defining integrated biochemical indices of the quality of tomato fruits with different resistance to agents of bacterial disea­ses. Methods. In the course of performance biotechnological methods were used to select callus cells with increased resistance to the agents of bacterial diseases, biochemical ones – determine qualitative and quantitative indicators of the tomato fruit quality, statistical ones – analyse experimental data. Results. Studied tomato varieties of Ukrainian breeding had different resistance to warm cells of agents of bacterial speck, bacterial black spot and to exopolysaccharides of bacterial canker agents. ‘Chaika’, ‘Klondaik’, ‘Zoreslav’, ‘Flandriia’, ‘Legin’, ‘Oberig’, ‘Atlasnyi’, ‘Gospodar’ and ‘Kimmeriiets’ tomato varieties were distinguished by high palatability traits and quality. Conclusions. It was found that tomato varieties ‘Chaika’, ‘Klondaik’ and ‘Zoreslav’ are resistant to bacterial canker, bacterial speck and bacterial black spot; ‘Flandriia’ and ‘Legin’ – to bacterial black spot, ‘Oberig’, ‘Atlasnyi’, ‘Gospodar’ and ‘Kimmeriiets’ – to bacterial speck.

  12. Bacterial pathogens of the bovine respiratory disease complex.

    Science.gov (United States)

    Griffin, Dee; Chengappa, M M; Kuszak, Jennifer; McVey, D Scott

    2010-07-01

    Pneumonia caused by the bacterial pathogens discussed in this article is the most significant cause of morbidity and mortality of the BRDC. Most of these infectious bacteria are not capable of inducing significant disease without the presence of other predisposing environmental factors, physiologic stressors, or concurrent infections. Mannheimia haemolytica is the most common and serious of these bacterial agents and is therefore also the most highly characterized. There are other important bacterial pathogens of BRD, such as Pasteurella multocida, Histophulus somni, and Mycoplasma bovis. Mixed infections with these organisms do occur. These pathogens have unique and common virulence factors but the resulting pneumonic lesions may be similar. Although the amount and quality of research associated with BRD has increased, vaccination and therapeutic practices are not fully successful. A greater understanding of the virulence mechanisms of the infecting bacteria and pathogenesis of pneumonia, as well as the characteristics of the organisms that allow tissue persistence, may lead to improved management, therapeutics, and vaccines. Copyright 2010 Elsevier Inc. All rights reserved.

  13. Secondary Metabolism and Biotrophic Lifestyle in the Tomato Pathogen Cladosporium fulvum

    Science.gov (United States)

    Collemare, Jérôme; Griffiths, Scott; Iida, Yuichiro; Karimi Jashni, Mansoor; Battaglia, Evy; Cox, Russell J.; de Wit, Pierre J. G. M.

    2014-01-01

    Cladosporium fulvum is a biotrophic fungal pathogen that causes leaf mould of tomato. Analysis of its genome suggested a high potential for production of secondary metabolites (SM), which might be harmful to plants and animals. Here, we have analysed in detail the predicted SM gene clusters of C. fulvum employing phylogenetic and comparative genomic approaches. Expression of the SM core genes was measured by RT-qrtPCR and produced SMs were determined by LC-MS and NMR analyses. The genome of C. fulvum contains six gene clusters that are conserved in other fungal species, which have undergone rearrangements and gene losses associated with the presence of transposable elements. Although being a biotroph, C. fulvum has the potential to produce elsinochrome and cercosporin toxins. However, the corresponding core genes are not expressed during infection of tomato. Only two core genes, PKS6 and NPS9, show high expression in planta, but both are significantly down regulated during colonization of the mesophyll tissue. In vitro SM profiling detected only one major compound that was identified as cladofulvin. PKS6 is likely involved in the production of this pigment because it is the only core gene significantly expressed under these conditions. Cladofulvin does not cause necrosis on Solanaceae plants and does not show any antimicrobial activity. In contrast to other biotrophic fungi that have a reduced SM production capacity, our studies on C. fulvum suggest that down-regulation of SM biosynthetic pathways might represent another mechanism associated with a biotrophic lifestyle. PMID:24465762

  14. Melatonin induces nitric oxide and the potential mechanisms relate to innate immunity against bacterial pathogen infection in Arabidopsis.

    Science.gov (United States)

    Shi, Haitao; Chen, Yinhua; Tan, Dun-Xian; Reiter, Russel J; Chan, Zhulong; He, Chaozu

    2015-08-01

    Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring small molecule, serving as important secondary messenger in the response of plants to various biotic and abiotic stresses. However, the interactions between melatonin and other important molecules in the plant stress response, especially in plant immunity, are largely unknown. In this study, we found that both melatonin and nitric oxide (NO) levels in Arabidopsis leaves were significantly induced by bacterial pathogen (Pst DC3000) infection. The elevated NO production was caused by melatonin as melatonin application enhanced endogenous NO level with great efficacy. Moreover, both melatonin and NO conferred improved disease resistance against Pseudomonas syringe pv. tomato (Pst) DC3000 infection in Arabidopsis. NO scavenger significantly suppressed the rise of NO which was induced by exogenous application of melatonin. As a result, the beneficial effects of melatonin on the expression of salicylic acid (SA)-related genes and disease resistance against bacterial pathogen infection were jeopardized by use of a NO scavenger. Consistently, melatonin application significantly lost its effect on the innate immunity against P. syringe pv. tomato (Pst) DC3000 infection in NO-deficient mutants of Arabidopsis. The results indicate that melatonin-induced NO production is responsible for innate immunity response of Arabidopsis against Pst DC3000 infection. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Rhizosphere-associated Pseudomonas induce systemic resistance to herbivores at the cost of susceptibility to bacterial pathogens.

    Science.gov (United States)

    Haney, Cara H; Wiesmann, Christina L; Shapiro, Lori R; Melnyk, Ryan A; O'Sullivan, Lucy R; Khorasani, Sophie; Xiao, Li; Han, Jiatong; Bush, Jenifer; Carrillo, Juli; Pierce, Naomi E; Ausubel, Frederick M

    2017-10-31

    Plant-associated soil microbes are important mediators of plant defence responses to diverse above-ground pathogen and insect challengers. For example, closely related strains of beneficial rhizosphere Pseudomonas spp. can induce systemic resistance (ISR), systemic susceptibility (ISS) or neither against the bacterial foliar pathogen Pseudomonas syringae pv. tomato DC3000 (Pto DC3000). Using a model system composed of root-associated Pseudomonas spp. strains, the foliar pathogen Pto DC3000 and the herbivore Trichoplusia ni (cabbage looper), we found that rhizosphere-associated Pseudomonas spp. that induce either ISS and ISR against Pto DC3000 all increased resistance to herbivory by T. ni. We found that resistance to T. ni and resistance to Pto DC3000 are quantitative metrics of the jasmonic acid (JA)/salicylic acid (SA) trade-off and distinct strains of rhizosphere-associated Pseudomonas spp. have distinct effects on the JA/SA trade-off. Using genetic analysis and transcriptional profiling, we provide evidence that treatment of Arabidopsis with Pseudomonas sp. CH267, which induces ISS against bacterial pathogens, tips the JA/SA trade-off towards JA-dependent defences against herbivores at the cost of a subset of SA-mediated defences against bacterial pathogens. In contrast, treatment of Arabidopsis with the ISR strain Pseudomonas sp. WCS417 disrupts JA/SA antagonism and simultaneously primes plants for both JA- and SA-mediated defences. Our findings show that ISS against the bacterial foliar pathogens triggered by Pseudomonas sp. CH267, which is a seemingly deleterious phenotype, may in fact be an adaptive consequence of increased resistance to herbivory. Our work shows that pleiotropic effects of microbiome modulation of plant defences are important to consider when using microbes to modify plant traits in agriculture. © 2017 John Wiley & Sons Ltd.

  16. Metabolomics of tomato xylem sap during bacterial wilt reveals Ralstonia solanacearum produces abundant putrescine, a metabolite that accelerates wilt disease

    NARCIS (Netherlands)

    Lowe-Power, Tiffany M.; Hendrich, Connor G.; Roepenack-Lahaye, von Edda; Li, Bin; Wu, Dousheng; Mitra, Raka; Dalsing, Beth L.; Ricca, Patrizia; Naidoo, Jacinth; Cook, David; Jancewicz, Amy; Masson, Patrick; Thomma, Bart; Lahaye, Thomas; Michael, Anthony J.; Allen, Caitilyn

    2017-01-01

    Ralstonia solanacearum thrives in plant xylem vessels and causes bacterial wilt disease despite the low nutrient content of xylem sap. We found that R. solanacearum manipulates its host to increase nutrients in tomato xylem sap, enabling it to grow better in sap from infected plants than in sap from

  17. Metabolomics of tomato xylem sap during bacterial wilt reveals Ralstonia solanacearum produces abundant putrescine, a metabolite that accelerates wilt disease.

    Science.gov (United States)

    Lowe-Power, Tiffany M; Hendrich, Connor G; von Roepenack-Lahaye, Edda; Li, Bin; Wu, Dousheng; Mitra, Raka; Dalsing, Beth L; Ricca, Patrizia; Naidoo, Jacinth; Cook, David; Jancewicz, Amy; Masson, Patrick; Thomma, Bart; Lahaye, Thomas; Michael, Anthony J; Allen, Caitilyn

    2017-12-07

    Ralstonia solanacearum thrives in plant xylem vessels and causes bacterial wilt disease despite the low nutrient content of xylem sap. We found that R. solanacearum manipulates its host to increase nutrients in tomato xylem sap, enabling it to grow better in sap from infected plants than in sap from healthy plants. Untargeted GC/MS metabolomics identified 22 metabolites enriched in R. solanacearum-infected sap. Eight of these could serve as sole carbon or nitrogen sources for R. solanacearum. Putrescine, a polyamine that is not a sole carbon or nitrogen source for R. solanacearum, was enriched 76-fold to 37 µM in R. solanacearum-infected sap. R. solanacearum synthesized putrescine via a SpeC ornithine decarboxylase. A ΔspeC mutant required ≥ 15 µM exogenous putrescine to grow and could not grow alone in xylem even when plants were treated with putrescine. However, co-inoculation with wildtype rescued ΔspeC growth, indicating R. solanacearum produced and exported putrescine to xylem sap. Intriguingly, treating plants with putrescine before inoculation accelerated wilt symptom development and R. solanacearum growth and systemic spread. Xylem putrescine concentration was unchanged in putrescine-treated plants, so the exogenous putrescine likely accelerated disease indirectly by affecting host physiology. These results indicate that putrescine is a pathogen-produced virulence metabolite. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Genome Assembly and Computational Analysis Pipelines for Bacterial Pathogens

    KAUST Repository

    Rangkuti, Farania Gama Ardhina

    2011-06-01

    Pathogens lie behind the deadliest pandemics in history. To date, AIDS pandemic has resulted in more than 25 million fatal cases, while tuberculosis and malaria annually claim more than 2 million lives. Comparative genomic analyses are needed to gain insights into the molecular mechanisms of pathogens, but the abundance of biological data dictates that such studies cannot be performed without the assistance of computational approaches. This explains the significant need for computational pipelines for genome assembly and analyses. The aim of this research is to develop such pipelines. This work utilizes various bioinformatics approaches to analyze the high-­throughput genomic sequence data that has been obtained from several strains of bacterial pathogens. A pipeline has been compiled for quality control for sequencing and assembly, and several protocols have been developed to detect contaminations. Visualization has been generated of genomic data in various formats, in addition to alignment, homology detection and sequence variant detection. We have also implemented a metaheuristic algorithm that significantly improves bacterial genome assemblies compared to other known methods. Experiments on Mycobacterium tuberculosis H37Rv data showed that our method resulted in improvement of N50 value of up to 9697% while consistently maintaining high accuracy, covering around 98% of the published reference genome. Other improvement efforts were also implemented, consisting of iterative local assemblies and iterative correction of contiguated bases. Our result expedites the genomic analysis of virulent genes up to single base pair resolution. It is also applicable to virtually every pathogenic microorganism, propelling further research in the control of and protection from pathogen-­associated diseases.

  19. Partial stem and leaf resistance against the fungal pathogen Botrytis cinerea in wild relatives of tomato

    NARCIS (Netherlands)

    Have, ten A.; Berloo, van R.; Lindhout, P.; Kan, van J.A.L.

    2007-01-01

    Tomato (Solanum lycopersicum) is one of many greenhouse crops that can be infected by the necrotrophic ascomycete Botrytis cinerea. Commercial cultivation of tomato is hampered by the lack of resistance. Quantitative resistance has been reported in wild tomato relatives, mostly based on leaf assays.

  20. A single natural nucleotide mutation alters bacterial pathogen host tropism.

    Science.gov (United States)

    Viana, David; Comos, María; McAdam, Paul R; Ward, Melissa J; Selva, Laura; Guinane, Caitriona M; González-Muñoz, Beatriz M; Tristan, Anne; Foster, Simon J; Fitzgerald, J Ross; Penadés, José R

    2015-04-01

    The capacity of microbial pathogens to alter their host tropism leading to epidemics in distinct host species populations is a global public and veterinary health concern. To investigate the molecular basis of a bacterial host-switching event in a tractable host species, we traced the evolutionary trajectory of the common rabbit clone of Staphylococcus aureus. We report that it evolved through a likely human-to-rabbit host jump over 40 years ago and that only a single naturally occurring nucleotide mutation was required and sufficient to convert a human-specific S. aureus strain into one that could infect rabbits. Related mutations were identified at the same locus in other rabbit strains of distinct clonal origin, consistent with convergent evolution. This first report of a single mutation that was sufficient to alter the host tropism of a microorganism during its evolution highlights the capacity of some pathogens to readily expand into new host species populations.

  1. Diversity, Pathogenicity, and Current Occurrence of Bacterial Wilt Bacterium Ralstonia solanacearum in Peru

    Directory of Open Access Journals (Sweden)

    Liliam Gutarra

    2017-07-01

    Full Text Available The current bacterial wilt infestation level in the potato fields in the Peruvian Andes was investigated by collecting stem samples from wilted plants and detecting Ralstonia solanacearum. In total 39 farmers’ fields located in the central and northern Peru between the altitudes 2111 and 3742 m above sea level were sampled. R. solanacearum was detected in 19 fields, and in 153 out of the 358 samples analyzed. Phylogenetic analysis using the partial sequence of the endoglucanase gene on strains collected in Peru between 1966 and 2016 from potato, pepper, tomato, plantain or soil, divided the strains in phylotypes I, IIA, and IIB. The Phylotype IIB isolates formed seven sequevar groups including the previously identified sequevars 1, 2, 3, 4, and 25. In addition to this, three new sequevars of phylotype IIB were identified. Phylotype IIA isolates from Peru clustered together with reference strains previously assigned to sequevars 5, 39, 41, and 50, and additionally one new sequevar was identified. The Phylotype I strain was similar to the sequevar 18. Most of the Peruvian R. solanacearum isolates were IIB-1 strains. In the old collection sampled between 1966 and 2013, 72% were IIB-1 and in the new collection at 2016 no other strains were found. The pathogenicity of 25 isolates representing the IIA and IIB sequevar groups was tested on potato, tomato, eggplant and tobacco. All were highly aggressive on potato, but differed in pathogenicity on the other hosts, especially on tobacco. All IIA strains caused latent infection on tobacco and some strains also caused wilting, while IIB strains caused only few latent infections on this species. In conclusion, high molecular diversity was found among the R. solanacearum strains in Peru. Most of the variability was found in areas that are no longer used for potato cultivation and thus these strains do not pose a real threat for potato production in the country. Compared to the previous data from the 1990s

  2. Endoplasmic reticulum-quality control chaperones facilitate the biogenesis of cf receptor-like proteins involved in pathogen resistance of tomato

    NARCIS (Netherlands)

    Liebrand, T.W.H.; Smit, P.; Abd-El-Haliem, A.; Jonge, de R.; Cordewener, J.H.G.; America, A.H.P.; Sklenar, J.; Jones, A.M.; Robatzek, S.; Thomma, B.P.H.J.; Tameling, W.I.; Joosten, M.H.A.J.

    2012-01-01

    Cf proteins are receptor-like proteins (RLPs) that mediate resistance of tomato (Solanum lycopersicum) to the foliar pathogen Cladosporium fulvum. These transmembrane immune receptors, which carry extracellular leucine-rich repeats that are subjected to posttranslational glycosylation, perceive

  3. Bacterial food-borne pathogens in Indian food

    International Nuclear Information System (INIS)

    Bandekar, J.R.

    2015-01-01

    Food technology and food processing techniques have made tremendous advances in preservation of food and ensuring safety of food by killing food-borne pathogens. In addition to old techniques such as pasteurization, canning, dehydration, fermentation and salting, a number of new techniques such as radiation processing, high pressure technology and pulsed electric field technology are being applied for preservation of food and to ensure food safety. Total Quality Management (TQM) concepts have been developed to take care of food safety from farm to table. Hazard Analysis at Critical Control Points (HACCP) is being applied for mass scale production of food to make food free from pathogens. Despite these advances, food-borne diseases have become one of the most widespread public health problems in the world. About two thirds of all the outbreaks are traced to microbial contaminated food. According to World Health Organization (WHO) estimates, food-borne and waterborne diarrhoeal diseases kill an estimated 2 million people annually, including many children. Food safety is a major concern not only for developing countries but also for the developed countries. A number of factors such as emergence of new food-borne pathogens, development of drug resistance in pathogens, changing life style, globalization of the food supply etc. are responsible for the continuous persistence of food-borne diseases. The food-borne disease outbreaks due to E. coli O157:H7, Listeria monocytogenes, Salmonella and Campylobacter, are responsible for recall of many foods resulting in heavy losses to food industry. Due to consumer demand, a number of Ready-To-Eat (RTE) minimally processed foods are increasingly marketed; however, there is increased risk of foodborne diseases with these products. Food Technology Division of Bhabha Atomic Research Centre, Mumbai, has been working on food-borne bacterial pathogens particularly Salmonella, Campylobacter, Listeria monocytogenes, Vibrio and Aeromonasf

  4. Quorum sensing and bacterial pathogenicity: From molecules to disease

    Directory of Open Access Journals (Sweden)

    Antariksh Deep

    2011-01-01

    Full Text Available Quorum sensing in prokaryotic biology refers to the ability of a bacterium to sense information from other cells in the population when they reach a critical concentration (i.e. a Quorum and communicate with them. The "language" used for this intercellular communication is based on small, self-generated signal molecules called as autoinducers. Quorum sensing is thought to afford pathogenic bacteria a mechanism to minimize host immune responses by delaying the production of tissue-damaging virulence factors until sufficient bacteria have amassed and are prepared to overwhelm host defense mechanisms and establish infection. Quorum sensing systems are studied in a large number of gram-negative bacterial species belonging to α, β, and γ subclasses of proteobacteria. Among the pathogenic bacteria, Pseudomonas aeruginosa is perhaps the best understood in terms of the virulence factors regulated and the role the Quorum sensing plays in pathogenicity. Presently, Quorum sensing is considered as a potential novel target for antimicrobial therapy to control multi/all drug-resistant infections. This paper reviews Quorum sensing in gram positive and gram negative bacteria and its role in biofilm formation.

  5. Conventional and molecular methods to detect bacterial pathogens in mussels.

    Science.gov (United States)

    Gugliandolo, C; Lentini, V; Spanò, A; Maugeri, T L

    2011-01-01

    To detect Aeromonas spp., Salmonella spp., Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus in mussels and water samples from a farming area, conventional and molecular methods were applied to enrichment cultures. The aerolysin gene (aero) of Aeromonas spp., the invasion plasmid antigen B (ipaB) gene of Salmonella spp., the enterotoxin secretion protein (epsM) gene of V. cholerae, the species-specific region of 16S rRNA gene of V. vulnificus, the 16S-23S rDNA (IGS) gene of V. parahaemolyticus and the pR72H fragment of V. parahaemolyticus were amplified by multiplex polymerase chain reaction (PCR) assays on DNA extracted from enrichment cultures. The haemolysin gene (tdh) of pathogenic V. parahaemolyticus was also amplified. Conventional culture method allowed the isolation of V. parahaemolyticus and V. vulnificus from water and mussels. The genes aero, epsM and 16S rRNA of V. vulnificus were occasionally detected in the enrichment cultures. In mussels, the ipaB and IGS genes were detected from June to September and from April to November, respectively. All genes, except aero, were amplified from mussels collected in September, when pathogenic V. parahaemolyticus (tdh+) strains were also isolated. Multiplex-PCR assays were more sensitive and faster than conventional procedures. The results emphasize the need of an accurate and rapid detection of bacterial pathogens in mussels to protect human health. © 2010 The Authors. Letters in Applied Microbiology © 2010 The Society for Applied Microbiology.

  6. Over-expression of snakin-2 and extensin-like protein genes restricts pathogen invasiveness and enhances tolerance to Clavibacter michiganensis subsp. michiganensis in transgenic tomato (Solanum lycopersicum).

    Science.gov (United States)

    Balaji, Vasudevan; Smart, Christine D

    2012-02-01

    Two tomato proteins were evaluated by over-expression in transgenic tomato for their ability to confer resistance to Clavibacter michiganensis subsp. michiganensis (Cmm). Snakin-2 (SN2) is a cysteine-rich peptide with broad-spectrum antimicrobial activity in vitro while extensin-like protein (ELP) is a major cell-wall hydroxyproline-rich glycoprotein linked with plant response to pathogen attack and wounding. Tomato plants, cultivar Mountain Fresh, were transformed via Agrobacterium tumefaciens harboring a binary vector for expression of the full-length SN2 gene or ELP cDNA under the regulation of the CaMV 35S promoter. Molecular characterization of PCR-positive putative T(0) transgenic plants by Northern analysis revealed constitutive over-expression of SN2 and ELP mRNA. Junction fragment analysis by Southern blot showed that three of the four SN2 over-expressing T(0) lines had single copies of complete T-DNAs while the other line had two complete T-DNA copies. All four ELP over-expressing T(0) lines had a single copy T-DNA insertion. Semi-quantitative RT-PCR analysis of T(1) plants revealed constitutive over-expression of SN2 and ELP. Transgenic lines that accumulated high levels of SN2 or ELP mRNA showed enhanced tolerance to Cmm resulting in a significant delay in the development of wilt symptoms and a reduction in the size of canker lesions compared to non-transformed control plants. Furthermore, in transgenic lines over-expressing SN2 or ELP bacterial populations were significantly lower (100-10,000-fold) than in non-transformed control plants. These results demonstrate that SN2 and ELP over-expression limits Cmm invasiveness suggesting potential in vivo antibacterial activity and possible biotechnological application for these two defense proteins.

  7. Polylysogeny magnifies competitiveness of a bacterial pathogen in vivo.

    Science.gov (United States)

    Burns, Nicola; James, Chloe E; Harrison, Ellie

    2015-04-01

    The rise of next generation sequencing is revealing a hidden diversity of temperate phages within the microbial community. While a handful of these phages have been well characterized, for the vast majority, the role of phage carriage, and especially multiple phage carriage, is poorly understood. The Liverpool epidemic strain of Pseudomonas aeruginosa is an aggressive pathogen in cystic fibrosis lung infections that has recently been found to contain several unique prophages within its genome. Here, we experimentally investigate the role of two of these phages in vivo, using an insect model of infection. We find that while no benefit is conferred by phage carriage in single bacterial infections, phages confer a large fitness advantage during mixed infections by mediating bacteria-bacteria competition. Differences between the two phages appeared to be associated with the rate at which the competitor acquired the phage, and therefore resistance. However, the advantage was greatest in the polylysogen, carrying both phages. These findings suggest that the LES phages may play an important role in host invasions and more generally show that the carriage of multiple phages may itself be beneficial by hindering the spread of resistance in rival bacterial populations.

  8. Canine bacterial urinary tract infections: new developments in old pathogens.

    Science.gov (United States)

    Thompson, Mary F; Litster, Annette L; Platell, Joanne L; Trott, Darren J

    2011-10-01

    Uncomplicated bacterial urinary tract infections (UTIs) occur commonly in dogs. Persistent or recurrent infections are reported less frequently. They typically occur in dogs with an underlying disease and are sometimes asymptomatic, especially in dogs with predisposing chronic disease. Escherichia coli is the organism most frequently cultured in both simple and complicated UTIs. Organisms such as Enterococcus spp. and Pseudomonas spp. are less common in uncomplicated UTI, but become increasingly prominent in dogs with recurrent UTI. The ability of bacteria to acquire resistance to antimicrobials and/or to evade host immune defence mechanisms is vital for persistence in the urinary tract. Antimicrobial therapy limitations and bacterial strains with such abilities require novel control strategies. Sharing of resistant bacteria between humans and dogs has been recently documented and is of particular concern for E. coli O25b:H4-ST131 strains that are both virulent and multi-drug resistant. The epidemiology of complicated UTIs, pathogenic traits of uropathogens and new therapeutic concepts are outlined in this review. Copyright © 2011. Published by Elsevier Ltd.

  9. Advances in genetic manipulation of obligate intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Paul eBeare

    2011-05-01

    Full Text Available Infections by obligate intracellular bacterial pathogens result in significant morbidity and mortality worldwide. These bacteria include Chlamydia spp., which causes millions of cases of sexually transmitted disease and blinding trachoma annually, and members of the α-proteobacterial genera Anaplasma, Ehrlichia, Orientia and Rickettsia, agents of serious human illnesses including epidemic typhus. Coxiella burnetii, the agent of human Q fever, has also been considered a prototypical obligate intracellular bacterium, but recent host cell-free (axenic growth has rescued it from obligatism. The historic genetic intractability of obligate intracellular bacteria has severely limited molecular dissection of their unique lifestyles and virulence factors involved in pathogenesis. Host cell restricted growth is a significant barrier to genetic transformation that can make simple procedures for free-living bacteria, such as cloning, exceedingly difficult. Low transformation efficiency requiring long term culture in host cells to expand small transformant populations is another obstacle. Despite numerous technical limitations, the last decade has witnessed significant gains in genetic manipulation of obligate intracellular bacteria including allelic exchange. Continued development of genetic tools should soon enable routine mutation and complementation strategies for virulence factor discovery and stimulate renewed interest in these refractory pathogens. In this review, we discuss the technical challenges associated with genetic transformation of obligate intracellular bacteria and highlight advances made with individual genera.

  10. Effects of post-harvest handling conditions on internalization and growth of Salmonella enterica in tomatoes

    Science.gov (United States)

    Internalization during post-harvest handling is a significant route of tomato contamination by phytopathogens and foodborne human pathogens. This study was conducted to determine the effect of immersion time, immersion depth, and the temperature differential between bacterial suspension and tomato p...

  11. Comparative genomics of pseudomonas syringae pathovar tomato reveals novel chemotaxis pathways associated with motility and plant pathogenicity

    Science.gov (United States)

    The majority of bacterial foliar plant pathogens must invade the apoplast of host plants through points of ingress, such as stomata or wounds, replicate to high population density and cause disease. How pathogens navigate plant surfaces to locate invasion sites remains poorly understood. Many bacter...

  12. Factors that affect proliferation of Salmonella in tomatoes post-harvest: the roles of seasonal effects, irrigation regime, crop and pathogen genotype.

    Science.gov (United States)

    Marvasi, Massimiliano; Hochmuth, George J; Giurcanu, Mihai C; George, Andrée S; Noel, Jason T; Bartz, Jerry; Teplitski, Max

    2013-01-01

    Fresh fruits and vegetables become increasingly recognized as vehicles of human salmonellosis. Physiological, ecological, and environmental factors are all thought to contribute to the ability of Salmonella to colonize fruits and vegetables pre- and post-harvest. The goal of this study was to test how irrigation levels, fruit water congestion, crop and pathogen genotypes affect the ability of Salmonella to multiply in tomatoes post-harvest. Fruits from three tomato varieties, grown over three production seasons in two Florida locations, were infected with seven strains of Salmonella and their ability to multiply post-harvest in field-grown tomatoes was tested. The field experiments were set up as a two-factor factorial split plot experiment, with the whole-plot treatments arranged in a randomized complete-block design. The irrigation treatment (at three levels) was the whole-plot factor, and the split-plot factor was tomato variety, with three levels. The significance of the main, two-way, and three-way interaction effects was tested using the (type III) F-tests for fixed effects. Mean separation for each significant fixed effect in the model was performed using Tukey's multiple comparison testing procedure. The irrigation regime per se did not affect susceptibility of the crop to post-harvest proliferation of Salmonella. However, Salmonella grew significantly better in water-congested tissues of green tomatoes. Tomato maturity and genotype, Salmonella genotype, and inter-seasonal differences were the strongest factors affecting proliferation. Red ripe tomatoes were significantly and consistently more conducive to proliferation of Salmonella. Tomatoes harvested in the driest, sunniest season were the most conducive to post-harvest proliferation of the pathogen. Statistically significant interactions between production conditions affected post-harvest susceptibility of the crop to the pathogen. UV irradiation of tomatoes post-harvest promoted Salmonella growth.

  13. Manipulation of host membranes by the bacterial pathogens Listeria, Francisella, Shigella and Yersinia.

    Science.gov (United States)

    Pizarro-Cerdá, Javier; Charbit, Alain; Enninga, Jost; Lafont, Frank; Cossart, Pascale

    2016-12-01

    Bacterial pathogens display an impressive arsenal of molecular mechanisms that allow survival in diverse host niches. Subversion of plasma membrane and cytoskeletal functions are common themes associated to infection by both extracellular and intracellular pathogens. Moreover, intracellular pathogens modify the structure/stability of their membrane-bound compartments and escape degradation from phagocytic or autophagic pathways. Here, we review the manipulation of host membranes by Listeria monocytogenes, Francisella tularensis, Shigella flexneri and Yersinia spp. These four bacterial model pathogens exemplify generalized strategies as well as specific features observed during bacterial infection processes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Agrobacterium-mediated transformation of tomato with rolB gene results in enhancement of fruit quality and foliar resistance against fungal pathogens.

    Science.gov (United States)

    Arshad, Waheed; Haq, Ihsan-ul-; Waheed, Mohammad Tahir; Mysore, Kirankumar S; Mirza, Bushra

    2014-01-01

    Tomato (Solanum lycopersicum L.) is the second most important cultivated crop next to potato, worldwide. Tomato serves as an important source of antioxidants in human diet. Alternaria solani and Fusarium oxysporum cause early blight and vascular wilt of tomato, respectively, resulting in severe crop losses. The foremost objective of the present study was to generate transgenic tomato plants with rolB gene and evaluate its effect on plant morphology, nutritional contents, yield and resistance against fungal infection. Tomato cv. Rio Grande was transformed via Agrobacterium tumefaciens harbouring rolB gene of Agrobacterium rhizogenes. rolB. Biochemical analyses showed considerable improvement in nutritional quality of transgenic tomato fruits as indicated by 62% increase in lycopene content, 225% in ascorbic acid content, 58% in total phenolics and 26% in free radical scavenging activity. Furthermore, rolB gene significantly improved the defence response of leaves of transgenic plants against two pathogenic fungal strains A. solani and F. oxysporum. Contrarily, transformed plants exhibited altered morphology and reduced fruit yield. In conclusion, rolB gene from A. rhizogenes can be used to generate transgenic tomato with increased nutritional contents of fruits as well as improved foliar tolerance against fungal pathogens.

  15. Agrobacterium-mediated transformation of tomato with rolB gene results in enhancement of fruit quality and foliar resistance against fungal pathogens.

    Directory of Open Access Journals (Sweden)

    Waheed Arshad

    Full Text Available Tomato (Solanum lycopersicum L. is the second most important cultivated crop next to potato, worldwide. Tomato serves as an important source of antioxidants in human diet. Alternaria solani and Fusarium oxysporum cause early blight and vascular wilt of tomato, respectively, resulting in severe crop losses. The foremost objective of the present study was to generate transgenic tomato plants with rolB gene and evaluate its effect on plant morphology, nutritional contents, yield and resistance against fungal infection. Tomato cv. Rio Grande was transformed via Agrobacterium tumefaciens harbouring rolB gene of Agrobacterium rhizogenes. rolB. Biochemical analyses showed considerable improvement in nutritional quality of transgenic tomato fruits as indicated by 62% increase in lycopene content, 225% in ascorbic acid content, 58% in total phenolics and 26% in free radical scavenging activity. Furthermore, rolB gene significantly improved the defence response of leaves of transgenic plants against two pathogenic fungal strains A. solani and F. oxysporum. Contrarily, transformed plants exhibited altered morphology and reduced fruit yield. In conclusion, rolB gene from A. rhizogenes can be used to generate transgenic tomato with increased nutritional contents of fruits as well as improved foliar tolerance against fungal pathogens.

  16. [Bacterial enteric pathogens' resistance to fluoroquinolones and last generation cephalosporines].

    Science.gov (United States)

    Damian, Maria; Usein, Codruţa-Romanita; Palade, Andi Marian; Băltoiu, Mădălina; Condei, Maria; Ciontea, Simona; Tatu-Chiţoiu, Dorina

    2010-01-01

    The increase of incidence of resistance to the antibiotics became the most worrisome subject within the clinical and research communities in the medical fields. Intrinsic resistance genetic mutations, horizontal transfer of mobile structures carrying genes coding for resistance to the antibiotics within the pan-microbial genome are representing the bacterial resistome which is bearing the genetic information regarding the defensive mechanisms developed by micro-organisms to protect themselves against antibiotics. Rice in the resistance of enteric bacteria, pathogens involved in a large number of human infections, to the cephalosporin of last generation and to the fluoroquinolones is a very actual subject in the medical area. Production of beta-lactamases with extended spectrum is the most important enzymatic defence system, developed by micro-organisms, consisting in the inactivation of beta-lactam antibiotics by destroying the beta-lactam ring. Enterobacteria are able to produce beta-lactamases of type TEM, SHV and/or CTX-M. Punctual mutations in nucleotide structure of bla genes, coding for beta-lactamases synthesis, are leading on production of a large diversity of enzymes with enlarged spectrum of activity (ESBL). At the beginning of 90's the first beta-lactamases resistance to clavulanic acid were detected and in our days more then 170 TEM, 120 SVH and 90 CTX-MESBLs are known. Escherichia coli strains are producing, firstly, TEM ESBLs, Klebsiella pneumoniae SHV ESBLs. and both are producing CTX-M type ESBLs, are resistant to the fluoroquinolones due to punctual mutations in nucleotide structure of gyr gene coding for gyrases production, enzymes involved in nucleic acids replication. Resistance to the antibiotics with extended activity is a public health threat due to their capacity of large spreading within bacterial population, when the coding structures are located on mobile genetic structures. The menace increase when genes coding for fluoroquinolones

  17. The Arabidopsis ATAF1, a NAC transcription factor, is a negative regulator of defense responses against necrotrophic fungal and bacterial pathogens.

    Science.gov (United States)

    Wang, Xiao'e; Basnayake, B M Vindhya S; Zhang, Huijuan; Li, Guojun; Li, Wei; Virk, Nasar; Mengiste, Tesfaye; Song, Fengming

    2009-10-01

    Transcription factors of the NAC family are known to be involved in various growth or developmental processes and in regulation of response to environmental stresses. In the present study, we report that Arabidopsis ATAF1 is a negative regulator of defense responses against both necrotrophic fungal and bacterial pathogens. Expression of ATAF1 was downregulated after infection with Botrytis cinerea or Pseudomonas syringae pv. tomato or after treatment with salicylic acid (SA), jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (the precursor of ethylene biosynthesis). Transgenic plants that overexpress the ATAF1 gene (ATAF1-OE) showed increased susceptibility while expression of an ATAF1 chimeric repressor construct (ATAF1-SRDX) exhibited enhanced resistance to P. syringae pv. tomato DC3000, B. cinerea, and Alternaria brassicicola. The ataf1 mutant plants showed no significant resistance against the pathogens tested. After inoculation with B. cinerea or P. syringae pv. tomato DC3000, expressions of defense-related genes PR-1, PR-5. and PDF1.2 were upregulated in the ATAF1-SRDX plants but attenuated or unchanged in the ATAF1-OE plants. In ATAF1-OE plants, SA-induced expression of pathogenesis-related genes and disease resistance against P. syringae pv. tomato DC3000 was partially suppressed. Increased levels of reactive oxygen species (i.e., H(2)O(2) and superoxide anion) accumulated only in the ATAF1-OE but not in the ATAF1-SRDX plants after Botrytis spp. infection. Our studies provide direct genetic evidence for the role of ATAF1 as a negative regulator of defense response against different type of pathogens.

  18. Effect of essential oil of Origanum rotundifolium on some plant pathogenic bacteria, seed germination and plant growth of tomato

    Science.gov (United States)

    Dadaşoǧlu, Fatih; Kotan, Recep; Karagöz, Kenan; Dikbaş, Neslihan; Ćakmakçi, Ramazan; Ćakir, Ahmet; Kordali, Şaban; Özer, Hakan

    2016-04-01

    The aim of this study is to determine effect of Origanum rotundifolium's essential oil on some plant pathogenic bacterias, seed germination and plant growth of tomato. Xanthomonas axanopodis pv. vesicatoria strain (Xcv-761) and Clavibacter michiganensis ssp. michiganensis strain (Cmm) inoculated to tomato seed. The seeds were tested for germination in vitro and disease severity and some plant growth parameters in vivo. In vitro assay, maximum seed germination was observed at 62,5 µl/ml essential oil treatment in seeds inoculated with Xcv-761 and at 62,5 µl/ml essential oil and streptomycin treatment in seeds inoculated with Cmm. The least infected cotiledon number was observed at 500 µg/ml streptomycin treatment in seeds inoculated with Cmm. In vivo assay, maximum seed germination was observed at 250 µl/ml essential oil teratment in tomato inoculated with Cmm. Lowest disease severity, is seen in the CMM infected seeds with 250 µl/ml essential oil application these results were statistically significant when compared with pathogen infected seeds. Similarly, in application conducted with XCV-761 infected seed, the lowest disease severity was observed for seeds as a result of 250 µl/ml essential oil application. Also according to the results obtained from essential oil application of CMM infected seeds conducted with 62,5 µl/ml dose; while disease severity was found statistically insignificant compared to 250 µl/ml to essential oil application, ıt was found statistically significant compared to pathogen infected seeds. The results showed that essential oil of O. rotundifolium has a potential for some suppressed plant disease when it is used in appropriate dose.

  19. Assessment of bacterial pathogens in fresh rainwater and airborne particulate matter using Real-Time PCR

    Science.gov (United States)

    Kaushik, Rajni; Balasubramanian, Rajasekhar

    2012-01-01

    Bacterial pathogens in airborne particulate matter (PM) and in rainwater (RW) were detected using a robust and sensitive Real-Time PCR method. Both RW and PM were collected simultaneously in the tropical atmosphere of Singapore, which were then subjected to analysis for the presence of selected bacterial pathogens and potential pathogen of health concern ( Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Aeromonas hydrophila). These pathogens were found to be prevalent in both PM and RW samples with E. coli being the most prevalent potential pathogen in both types of samples. The temporal distribution of these pathogens in PM and RW was found to be similar to each other. Using the proposed microbiological technique, the atmospheric deposition (dry and wet deposition) of bacterial pathogens to lakes and reservoirs can be studied in view of growing concerns about the outbreak of waterborne diseases.

  20. PathogenFinder - Distinguishing Friend from Foe Using Bacterial Whole Genome Sequence Data

    DEFF Research Database (Denmark)

    Cosentino, Salvatore; Larsen, Mette Voldby; Aarestrup, Frank Møller

    2013-01-01

    approaches. We describe PathogenFinder (http://cge.cbs.dtu.dk/services/PathogenFinder/), a web-server for the prediction of bacterial pathogenicity by analysing the input proteome, genome, or raw reads provided by the user. The method relies on groups of proteins, created without regard to their annotated...

  1. Culture -independent Pathogenic Bacterial Communities in Bottled Mineral Water

    Directory of Open Access Journals (Sweden)

    Hamdy A. Hassan

    2015-08-01

    Full Text Available Bottled mineral water (BMW is an alternative to mains water and consider it to be better and safer. Access to safe BMW from the bacteria involving potential health hazard is essential to health. Cultivation-independent technique PCR-based single-strand conformation polymorphism (SSCP for genetic profiling of PCR-amplified 16S rRNA genes was performed using Com primer set targeting the 16S rRNA genes for detection of pathogenic bacteria in bottled mineral water from the final product of six factories for bottled mineral drinking water in Wadi El-natron region- Egypt. These factories use often ozone technology to treat large quantities of water because of its effectiveness in purifying and conditioning water. A total of 27 single products were isolated from the profiles by PCR re-amplification and cloning. Sequence analysis of 27 SSCP bands revealed that the 16S rRNA sequences were clustered into seven operational taxonomic units (OTUs and the compositions of the communities of the six samples were all common. The results showed that most communities from phyla Alphaproteobacteria and certainly in the Sphingomonas sp. Culture-independent approaches produced complementary information, thus generating a more accurate view for the bacterial community in the BMW, particularly in the disinfection step, as it constitutes the final barrier before BMW distribution to the consumer

  2. Host-pathogen interactions and bacterial survival under phage fluctuations

    Science.gov (United States)

    Skanata, Antun; Kussell, Edo

    Environmental changes can have profound effects on ecosystems, leading to drastic outcomes such as extinction and desertification. Quantifying, predicting, and ultimately preventing those transitions is a key problem in the field. Our previous work in microbial systems has shown that fluctuations in environments drive transitions to alternate evolutionary optima, which can be either smooth or abrupt. The long term growth rate, an analog of free energy for population dynamics, has been used to distinguish under what conditions those transitions will occur. Our framework, which uses the mean field approximation to compute the long term growth rate in fluctuating environments, is uniquely positioned to treat more complex dependencies that allow coexistence among species sharing resources or infected by common pathogens. Here we present a simple model of a bacterial community subjected to fluctuating phage infections that outlines the regimes where species diversity results in long-term stability. We identify prevalent, but often counter-intuitive, strategies that bacteria use to protect against infection, and find a new general principle in the evolution of phage resistance. Our results, which predict the transition regimes, have implications for a broad range of ecological models.

  3. Combination treatment of chlorine dioxide gas and aerosolized sanitizer for inactivating foodborne pathogens on spinach leaves and tomatoes.

    Science.gov (United States)

    Park, Sang-Hyun; Kang, Dong-Hyun

    2015-08-17

    The objective of this study was to evaluate the antimicrobial effect of chlorine dioxide (ClO2) gas and aerosolized sanitizer, when applied alone or in combination, on the survival of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes inoculated onto spinach leaves and tomato surfaces. Spinach leaves and tomatoes were inoculated with a cocktail of three strains each of the three foodborne pathogens. ClO2 gas (5 or 10 ppmv) and aerosolized peracetic acid (PAA) (80 ppm) were applied alone or in combination for 20 min. Exposure to 10 ppmv of ClO2 gas for 20 min resulted in 3.4, 3.3, and 3.4 log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes on spinach leaves, respectively. Treatment with 80 ppm of aerosolized PAA for 20 min caused 2.3, 1.9, and 0.8 log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. Combined treatment of ClO2 gas (10 ppmv) and aerosolized PAA (80 ppm) for 20 min caused 5.4, 5.1, and 4.1 log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. E. coli O157:H7, S. Typhimurium, and L. monocytogenes on tomatoes experienced similar reduction patterns to those on spinach leaves. As treatment time increased, most combinations of ClO2 gas and aerosolized PAA showed additive effects in the inactivation of the three pathogens. Combined treatment of ClO2 gas and aerosolized PAA produced injured cells of three pathogens on spinach leaves while generally did not produce injured cells of these pathogens on tomatoes. Combined treatment of ClO2 gas (10 ppmv) and aerosolized PAA (80 ppm) did not significantly (p>0.05) affect the color and texture of samples during 7 days of storage. Copyright © 2015. Published by Elsevier B.V.

  4. Rhizosphere Microbiome Recruited from a Suppressive Compost Improves Plant Fitness and Increases Protection against Vascular Wilt Pathogens of Tomato

    Science.gov (United States)

    Antoniou, Anastasis; Tsolakidou, Maria-Dimitra; Stringlis, Ioannis A.; Pantelides, Iakovos S.

    2017-01-01

    Suppressive composts represent a sustainable approach to combat soilborne plant pathogens and an alternative to the ineffective chemical fungicides used against those. Nevertheless, suppressiveness to plant pathogens and reliability of composts are often inconsistent with unpredictable effects. While suppressiveness is usually attributed to the compost’s microorganisms, the mechanisms governing microbial recruitment by the roots and the composition of selected microbial communities are not fully elucidated. Herein, the purpose of the study was to evaluate the impact of a compost on tomato plant growth and its suppressiveness against Fusarium oxysporum f. sp. lycopersici (Foxl) and Verticillium dahliae (Vd). First, growth parameters of tomato plants grown in sterile peat-based substrates including 20 and 30% sterile compost (80P/20C-ST and 70P/30C-ST) or non-sterile compost (80P/20C and 70P/30C) were evaluated in a growth room experiment. Plant height, total leaf surface, and fresh and dry weight of plants grown in the non-sterile compost mixes were increased compared to the plants grown in the sterile compost substrates, indicating the plant growth promoting activity of the compost’s microorganisms. Subsequently, compost’s suppressiveness against Foxl and Vd was evaluated with pathogenicity experiments on tomato plants grown in 70P/30C-ST and 70P/30C substrates. Disease intensity was significantly less in plants grown in the non-sterile compost than in those grown in the sterile compost substrate; AUDPC was 2.3- and 1.4-fold less for Foxl and Vd, respectively. Moreover, fungal quantification in planta demonstrated reduced colonization in plants grown in the non-sterile mixture. To further investigate these findings, we characterized the culturable microbiome attracted by the roots compared to the unplanted compost. Bacteria and fungi isolated from unplanted compost and the rhizosphere of plants were sequence-identified. Community-level analysis revealed

  5. Ceftaroline activity tested against contemporary Latin American bacterial pathogens (2011

    Directory of Open Access Journals (Sweden)

    Robert K. Flamm

    2014-03-01

    Full Text Available A total of 2484 target bacterial pathogens were collected (one per patient episode from patients in 16 Latin American medical centers located in seven nations during 2011. Isolate identity was confirmed at a coordinating laboratory and susceptibility testing was performed for ceftaroline and comparator agents according to reference broth microdilution methods. A total of 30.0% of isolates were from respiratory tract, 29.4% from skin and skin structure, 21.4% from blood stream, 7.9% from urinary tract and 11.3% from other sites. Ceftaroline was active against Staphylococcus aureus (42.8% MRSA with 83.6% of the isolates at ≤1 mg/L and all isolates at ≤2 mg/L (MIC5090, 0.25/2 mg/L. National MRSA rates ranged from a low of 28.8% in Colombia to a high of 68.1% in Chile. All Streptococcus pyogenes and Streptococcus agalactiae were susceptible to ceftaroline (MIC50/90 values were at ≤0.015/≤0.015 mg/L for both. All Streptococcus pneumoniae were susceptible to ceftaroline, linezolid, tigecycline and vancomycin. Susceptibility to ceftriaxone was at 88.4% (CLSI non-meningitis interpretive criteria and 73.9% (CLSI meningitis interpretive criteria for all S. pneumoniae. Ceftriaxone susceptibility was only at 33.3% (CLSI non-meningitis interpretive criteria and 0.0% (CLSI meningitis interpretive criteria for penicillin-intermediate (penicillin MIC, 4 mg/L strains. All Haemophilus influenzae (29.4% β-lactamase-positive isolates were susceptible to ceftaroline, amoxicillin–clavulanate, ceftriaxone, and levofloxacin. For the Latin American region, the ESBL-phenotype rate was 37.6% for Escherichia coli and 53.3% for Klebsiella pneumoniae. Ceftaroline was not active against ESBL-phenotype strains but was active against >90.0% of the non-ESBL-phenotype. The spectrum of activity of ceftaroline against pathogens from Latin America indicates that it merits further study for its potential use in the Latin American region.

  6. Molecular marker-assisted selection for resistance to pathogens in tomato

    International Nuclear Information System (INIS)

    Barone, A.; Frusciante, L.

    2007-01-01

    Since the 1980s, the use of molecular markers has been suggested to improve the efficiency of releasing resistant varieties, thus overcoming difficulties met with classical breeding. For tomato, a high-density molecular map is available in which more than 40 resistance genes are localized. Markers linked to these genes can be used to speed up gene transfer and pyramiding. Suitable PCR markers targeting resistance genes were constructed directly on the sequences of resistance genes or on restriction fragment length polymorphisms (RFLPs) tightly linked to them, and used to select resistant genotypes in backcross schemes. In some cases, the BC 5 generation was reached, and genotypes that cumulated two homozygous resistant genes were also obtained. These results supported the feasibility of using marker-assisted selection (MAS) in tomato and reinforcing the potential of this approach for other genes, which is today also driven by the development of new techniques and increasing knowledge about the tomato genome. (author)

  7. Genetic transformation of the tomato pathogen Pyrenochaeta lycopersici allowed gene knockout using a split-marker approach.

    Science.gov (United States)

    Aragona, Maria; Valente, Maria Teresa

    2015-05-01

    Pyrenochaeta lycopersici, as other soil-transmitted fungal pathogens, generally received little attention compared to the pathogens affecting the aerial parts of the plants, although causing stunt and important fruit yield reduction of agronomic relevant crops. The scope of this study was to develop a system allowing to investigate the functional role of P. lycopersici genes putatively involved in the corky root rot of tomato. A genetic transformation system based on a split-marker approach was developed and tested to knock out a P. lycopersici gene encoding for a lytic polysaccharide monooxygenase (Plegl1) induced during the disease development. The regions flanking Plegl1 gene were fused with the overlapping parts of hygromycin marker gene, to favour homologous recombination. We were able to obtain four mutants not expressing the Plegl1 gene though, when tested on a susceptible tomato cultivar, Plegl1 mutants showed unaltered virulence, compared with the wild-type strain. The strategy illustrated in the present work demonstrated for the first time that homologous recombination occurs in P. lycopersici. Moreover, a transformation system mediated by Agrobacterium tumefaciens was established and stable genetic transformants have been obtained. The transformation systems developed represent important tools for investigating both the role of genes putatively involved in P. lycopersici interaction with host plant and the function of other physiological traits which emerged to be genetically expanded from the recent genome sequencing of this fungus.

  8. Balancing selection at the tomato RCR3 Guardee gene family maintains variation in strength of pathogen defense.

    Directory of Open Access Journals (Sweden)

    Anja C Hörger

    Full Text Available Coevolution between hosts and pathogens is thought to occur between interacting molecules of both species. This results in the maintenance of genetic diversity at pathogen antigens (or so-called effectors and host resistance genes such as the major histocompatibility complex (MHC in mammals or resistance (R genes in plants. In plant-pathogen interactions, the current paradigm posits that a specific defense response is activated upon recognition of pathogen effectors via interaction with their corresponding R proteins. According to the "Guard-Hypothesis," R proteins (the "guards" can sense modification of target molecules in the host (the "guardees" by pathogen effectors and subsequently trigger the defense response. Multiple studies have reported high genetic diversity at R genes maintained by balancing selection. In contrast, little is known about the evolutionary mechanisms shaping the guardee, which may be subject to contrasting evolutionary forces. Here we show that the evolution of the guardee RCR3 is characterized by gene duplication, frequent gene conversion, and balancing selection in the wild tomato species Solanum peruvianum. Investigating the functional characteristics of 54 natural variants through in vitro and in planta assays, we detected differences in recognition of the pathogen effector through interaction with the guardee, as well as substantial variation in the strength of the defense response. This variation is maintained by balancing selection at each copy of the RCR3 gene. Our analyses pinpoint three amino acid polymorphisms with key functional consequences for the coevolution between the guardee (RCR3 and its guard (Cf-2. We conclude that, in addition to coevolution at the "guardee-effector" interface for pathogen recognition, natural selection acts on the "guard-guardee" interface. Guardee evolution may be governed by a counterbalance between improved activation in the presence and prevention of auto-immune responses in

  9. High temperature and bacteriophages can indirectly select for bacterial pathogenicity in environmental reservoirs.

    Directory of Open Access Journals (Sweden)

    Ville-Petri Friman

    2011-03-01

    Full Text Available The coincidental evolution hypothesis predicts that traits connected to bacterial pathogenicity could be indirectly selected outside the host as a correlated response to abiotic environmental conditions or different biotic species interactions. To investigate this, an opportunistic bacterial pathogen, Serratia marcescens, was cultured in the absence and presence of the lytic bacteriophage PPV (Podoviridae at 25°C and 37°C for four weeks (N = 5. At the end, we measured changes in bacterial phage-resistance and potential virulence traits, and determined the pathogenicity of all bacterial selection lines in the Parasemia plantaginis insect model in vivo. Selection at 37°C increased bacterial motility and pathogenicity but only in the absence of phages. Exposure to phages increased the phage-resistance of bacteria, and this was costly in terms of decreased maximum population size in the absence of phages. However, this small-magnitude growth cost was not greater with bacteria that had evolved in high temperature regime, and no trade-off was found between phage-resistance and growth rate. As a result, phages constrained the evolution of a temperature-mediated increase in bacterial pathogenicity presumably by preferably infecting the highly motile and virulent bacteria. In more general perspective, our results suggest that the traits connected to bacterial pathogenicity could be indirectly selected as a correlated response by abiotic and biotic factors in environmental reservoirs.

  10. Construction of a tomato leaf cDNA expression library and immunoscreening for the Pseudomonas syringae pv. tomato DC3000 HrpZ1 target protein

    OpenAIRE

    Österman, Janina

    2009-01-01

    Pseudomonas syringae pv. tomato DC3000 is a Gram-negative plant pathogen that causes bacterial speck disease on tomato. The virulence of this bacterium is based on the type III secretion system (T3SS). Similar systems are also used by many other plant and animal pathogens, as well as symbiotic bacteria. The T3SS enables the transfer of specific bacterial virulence proteins from the bacterial cytoplasm into the host cell. This secretion is mediated by a needle-like structure that penetrates th...

  11. Bacterial contamination of platelet concentrates: pathogen detection and inactivation methods

    Directory of Open Access Journals (Sweden)

    Dana Védy

    2009-04-01

    Full Text Available Whereas the reduction of transfusion related viral transmission has been a priority during the last decade, bacterial infection transmitted by transfusion still remains associated to a high morbidity and mortality, and constitutes the most frequent infectious risk of transfusion. This problem especially concerns platelet concentrates because of their favorable bacterial growth conditions. This review gives an overview of platelet transfusion-related bacterial contamination as well as on the different strategies to reduce this problem by using either bacterial detection or inactivation methods.

  12. Identification of Bacterial Plant Pathogens Using Multilocus Polymerase Chain Reaction/Electrospray Ionization-Mass Spectrometry

    Science.gov (United States)

    2008-01-01

    1156 PHYTOPATHOLOGY Techniques Identification of Bacterial Plant Pathogens Using Multilocus Polymerase Chain Reaction/Electrospray Ionization... Phytopathology 98:1156-1164. Polymerase chain reaction/electrospray ionization-mass spectrometry (PCR/ESI-MS, previously known as “TIGER”) utilizes PCR with...based assays have been developed for bacterial plant pathogens (6,12,13,16,18, reviewed in 19). PCR-based diagnos- tics can be highly specific and are

  13. Inhibitory Effect of Lactobacillus reuteri on Some Pathogenic Bacteria Isolated From Women With Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Eslami

    2014-08-01

    Full Text Available Background Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. Objectives The purpose of this study was to investigate the inhibitory effect of Lactobacillus reuteri on pathogenic bacteria isolated from women with bacterial vaginosis. Materials and Methods Ninety-six samples were obtained from vaginal discharge of women with bacterial vaginosis by a gynecologist with a Dacron swab and put in sterile tubes containing TSB broth and Thioglycollate broth. Then were immediately sent to the laboratory in cold chain for further assessment. Afterward, culture was transferred on blood agar, EMB, Palcam and differential diagnosis environments. Then cultures were incubated for 24 hours at 37 °C. Lactobacillus reuteri strains were cultured in MRS environment and transferred to laboratory. After purification of pathogenic bacteria, Lactobacillus reuteri inhibitory effect on pathogenic bacteria was evaluated by minimum inhibitory concentration (MIC and antibiogram. Statistical analysis was performed using SPSS software v.16. Results The results of this study demonstrated the inhibitory effect of Lactobacillus reuteri on some pathogenic bacteria that cause bacterial, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus agalactiae, Enterococcus, Listeria monocytogenes and E. coli. Microscopic examination of stained smears of most Lactobacillus and pathogenic bacteria showed reduced. The prevalence of abnormal vaginal discharge, history of drug use, contraceptive methods and douching were 61%, 55%, 42% and 13%, respectively. Significant difference was observed between the use and non-use of IUD in women with bacterial. Conclusions Our findings indicated the inhibitory effect of Lactobacillus reuteri on pathogenic bacteria that

  14. Survey of bacterial pathogens on leaves and seeds of red mangrove ...

    African Journals Online (AJOL)

    Bacterial pathogens of red mangrove (Rhizophora mangle) were investigated. 50 samples each of leaves and seeds (healthy and diseased) were randomly collected and used for the analysis. Mean bacterial counts obtained were: healthy and diseased leaves; 8.26 x 103 and 5.9 l x l03 cfu/ml respectively; healthy seeds ...

  15. Costs and benefits of bacterial culturing and pathogen reduction in the Netherlands

    NARCIS (Netherlands)

    Janssen, M.P.; van der Poel, C.L.; Buskens, E.; Bonneux, L.; Bonsel, G.J.; van Hout, B.A.

    2006-01-01

    BACKGROUND: Bacterial contamination is a life-threatening risk of blood transfusion, especially with platelet (PLT) transfusions. Bacterial culturing (BCU) of PLTs as well as pathogen reduction (PRT) reduce the likelihood of such contamination. The cost-effectiveness (CE) of these interventions was

  16. Bacterial pathogens in rainbow trout, Oncorhynchus mykiss (Walbaum), reared at Danish freshwater farms

    DEFF Research Database (Denmark)

    Dalsgaard, Inger; Madsen, Lone

    2000-01-01

    During a 2-year period, bacterial fish pathogens were monitored on five rainbow trout, Oncorhynchus mykirs (Walbaum), freshwater farms in Denmark. A total of 1206 fish were examined and 361 bacterial isolates were identified phenotypically. Enteric redmouth disease, furunculosis and rainbow trout...

  17. Tomato Cf resistance proteins mediate recognition of cognate homologous effectors from fungi pathogenic on dicots and monocots.

    Science.gov (United States)

    Stergiopoulos, Ioannis; van den Burg, Harrold A; Okmen, Bilal; Beenen, Henriek G; van Liere, Sabine; Kema, Gert H J; de Wit, Pierre J G M

    2010-04-20

    Most fungal effectors characterized so far are species-specific and facilitate virulence on a particular host plant. During infection of its host tomato, Cladosporium fulvum secretes effectors that function as virulence factors in the absence of cognate Cf resistance proteins and induce effector-triggered immunity in their presence. Here we show that homologs of the C. fulvum Avr4 and Ecp2 effectors are present in other pathogenic fungi of the Dothideomycete class, including Mycosphaerella fijiensis, the causal agent of black Sigatoka disease of banana. We demonstrate that the Avr4 homolog of M. fijiensis is a functional ortholog of C. fulvum Avr4 that protects fungal cell walls against hydrolysis by plant chitinases through binding to chitin and, despite the low overall sequence homology, triggers a Cf-4-mediated hypersensitive response (HR) in tomato. Furthermore, three homologs of C. fulvum Ecp2 are found in M. fijiensis, one of which induces different levels of necrosis or HR in tomato lines that lack or contain a putative cognate Cf-Ecp2 protein, respectively. In contrast to Avr4, which acts as a defensive virulence factor, M. fijiensis Ecp2 likely promotes virulence by interacting with a putative host target causing host cell necrosis, whereas Cf-Ecp2 could possibly guard the virulence target of Ecp2 and trigger a Cf-Ecp2-mediated HR. Overall our data suggest that Avr4 and Ecp2 represent core effectors that are collectively recognized by single cognate Cf-proteins. Transfer of these Cf genes to plant species that are attacked by fungi containing these cognate core effectors provides unique ways for breeding disease-resistant crops.

  18. Global analysis of the HrpL regulon in the plant pathogen Pseudomonas syringae pv. tomato DC3000 reveals new regulon members with diverse functions

    Science.gov (United States)

    The type III secretion system (T3SS) is required for virulence in the gram-negative plant pathogen Pseudomonas syringae pv. tomato DC3000. The alternative sigma factor HrpL directly regulates expression of T3SS genes via a consensus promoter sequence, often designated as the “hrp promoter.” Although...

  19. Atypical bacterial pathogens in community-acquired pneumonia in children: a hospital-based study.

    Science.gov (United States)

    Agarwal, Jyotsna; Awasthi, Shally; Rajput, Anuradha; Tiwari, Manoj; Jain, Amita

    2009-04-01

    A total of 243 children aged one month to five years with World Health Organization defined severe community acquired pneumonia were studied for the presence of atypical bacterial pathogens: 24 were found positive for mycoplasma infection. There was no significant association with any of the clinical, laboratory and radiological variables in children with pneumonia by the atypical pathogen.

  20. Xanthomonads and other yellow-pigmented, Xanthomonas-like bacteria associated with tomato seeds in Tanzania

    DEFF Research Database (Denmark)

    Mbega, Ernest Rashid; Wulff, Ednar Gadelha; Mabagala, R.B.

    2012-01-01

    Tomato (Solanum lycopersicum L.) seeds habour unique bacterial community that can be pathogenic or beneficial to their host. Xanthomonas causing bacterial leaf spot (BLSX) on tomato and other yellow-pigmented xanthomonads-like bacteria (XLB) that closely resemble BLSX were obtained from tomato...... seeds collected from Northern, Central and Southern highland regions of Tanzania. A total of 73 strains were isolated from 52 seed samples of 15 tomato cultivars. Results obtained with Biolog and sequence analysis of the 16S rRNA gene showed that samples originating from Central Tanzania harbored...... the most diverse populations of XLB and BLSX as compared to Northern and Southern Tanzania. The predominant bacterial genera in tomato seeds were Stenotrophomonas, Sphingomonas, Chryseobacterium, Xanthomonas, Pantoea and Flavobacterium. All strains identified by Biolog as Xanthomonas with exception...

  1. Analysis of bacterial communities and bacterial pathogens in a biogas plant by the combination of ethidium monoazide, PCR and Ion Torrent sequencing

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2014-01-01

    in the biogas reactor. It was found in batch experiments that bacterial pathogens showed the highest relative abundance and richness after 30days' post-digestion. Streptococcus bovis was found in all the samples. Our results showed that special attention should be paid to the post-digestion since the increase...... had a significant effect on the changes of bacterial community composition. The changes of bacterial community composition were also reflected in the changes of relative abundance of bacterial pathogens. The richness and relative abundance of bacterial pathogens were reduced after anaerobic digestion...... in relative abundance of bacterial pathogens after post-digestion might reflect regrowth of bacterial pathogens and limit biosolids disposal vectors. © 2014 Elsevier Ltd....

  2. Molecular assessment of bacterial pathogens - a contribution to drinking water safety.

    Science.gov (United States)

    Brettar, Ingrid; Höfle, Manfred G

    2008-06-01

    Human bacterial pathogens are considered as an increasing threat to drinking water supplies worldwide because of the growing demand of high-quality drinking water and the decreasing quality and quantity of available raw water. Moreover, a negative impact of climate change on freshwater resources is expected. Recent advances in molecular detection technologies for bacterial pathogens in drinking water bear the promise in improving the safety of drinking water supplies by precise detection and identification of the pathogens. More importantly, the array of molecular approaches allows understanding details of infection routes of waterborne diseases, the effects of changes in drinking water treatment, and management of freshwater resources.

  3. Rapid detection of bacterial pathogens using flourescence spectroscopy and chemometrics

    Science.gov (United States)

    This work presents the development of a method for rapid bacterial identification based on the fluorescence spectroscopy combined with multivariate analysis. Fluorescence spectra of pure three different genera of bacteria (Escherichia coli, Salmonella, and Campylobacter) were collected from 200...

  4. Surveillance of bacterial pathogens of diarrhoea in two selected sub ...

    African Journals Online (AJOL)

    GAR) have witnessed several episodes of cholera outbreaks, with some deaths. Compared to previous epidemics, which usually followed heavy rains, recent outbreaks show no seasonality. Objectives: To investigate infective bacterial diseases ...

  5. Detection of mastitis pathogens by analysis of volatile bacterial metabolites

    NARCIS (Netherlands)

    Hettinga, K.A.; Valenberg, van H.J.F.; Lam, T.J.G.M.; Hooijdonk, van A.C.M.

    2008-01-01

    The ability to detect mastitis pathogens based on their volatile metabolites was studied. Milk samples from cows with clinical mastitis, caused by Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus uberis, Streptococcus dysgalactiae, and Escherichia coli were collected. In

  6. Bacterial effect of accelerated electrons on several pathogens

    International Nuclear Information System (INIS)

    Butaev, M.K.; Bulkhanov, R.U.; Ryasnyanskii, I.V.; Mirzaev, B.Sh.; Safarov, A.N.; Suleymanov, R.D.

    2006-01-01

    colibacterillesis and salmonellosis of calves' were developed in RIVU. By widening the application field of developed radiation biotechnology the 'Polyvalent vaccine against pasteurellesis, salmonellosis and colibacterillesis of farm animals' was created in recent years. The mentioned radio vaccines were successfully tested in laboratory and working environment and are widely used in veterinary practice in the farms of the Republic of Uzbekistan [3].For further broadening of the possibility to use the radiation biotechnology and to enrich the native arsenal of veterinary bio medication, it is presently planned to conduct large-scale research on the use of accelerated electrons (AE) to obtain in perspective new preventive materials. Several results of the beginning stage of this research are given in the present report.The suspensions of pathogenic strains of pasteurellesis, salmonellosis and Escherichia Coli strains were exposed to irradiation by accelerated electrons of microtron MT-22C. Taking into account the slightly higher resistance of bacteria against irradiation by accelerated electrons as compared to gamma-irradiation, the doses from 400 to 1100 kRad were used. At this, the special attention was paid to control the distribution of linear density of the current in scanning of AE beam, the distribution of linear density of the current in perpendicular scanning of AE beam and the value of absorbed dose. The studies showed that at AE irradiation by 400 kRad dose the bacterial survival rate is about 10 %, at 500 kRad-2-3 %, 600 kRad- less than 1 %. At the dose of 800 kRad only isolated colonies of bacteria survived. At AE irradiation by 900 kRad- 1.1 MRad dose, there was no increase the growth of bacteria's number. Since these data were obtained at the multiple repetition of results, it can be supposed that the minimal absolute devitalizing AE irradiation dose of bacteria lies in the region 0.9-1.0 MRad. At this, some inter-species and even intra species peculiarities in the

  7. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    Science.gov (United States)

    Fouts, Derrick E; Matthias, Michael A; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L; Haake, David A; Haft, Daniel H; Hartskeerl, Rudy; Ko, Albert I; Levett, Paul N; Matsunaga, James; Mechaly, Ariel E; Monk, Jonathan M; Nascimento, Ana L T; Nelson, Karen E; Palsson, Bernhard; Peacock, Sharon J; Picardeau, Mathieu; Ricaldi, Jessica N; Thaipandungpanit, Janjira; Wunder, Elsio A; Yang, X Frank; Zhang, Jun-Jie; Vinetz, Joseph M

    2016-02-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  8. Molecular analysis of bacterial pathogens in otitis media with effusion.

    Science.gov (United States)

    Post, J C; Preston, R A; Aul, J J; Larkins-Pettigrew, M; Rydquist-White, J; Anderson, K W; Wadowsky, R M; Reagan, D R; Walker, E S; Kingsley, L A; Magit, A E; Ehrlich, G D

    To determine if the polymerase chain reaction (PCR) can detect bacterial DNA in pediatric middle ear effusions that are sterile by standard cultural methods. Single-center, blinded, comparative study of diagnostic assays. The PCR-based detection systems for Moraxella catarrhalis, Haemophilus influenzae, and Streptococcus pneumoniae were designed and validated using a battery of DNAs obtained from cultured bacteria. Chronic middle ear effusion specimens were collected and comparatively analyzed by culture and the PCR. Tertiary care pediatric hospital. A total of 97 middle ear effusions were collected from pediatric outpatients at Children's Hospital of Pittsburgh (Pa) during myringotomy and tube placement for chronic otitis media with effusion (duration > 3 months). All patients had failed multiple courses of antimicrobial therapy and were diagnosed by a combination of validated otoscopy and tympanograms. Differences in the percentage of positive test results between PCR-based assays and culture for M catarrhalis, H influenzae, and S pneumoniae. Of the 97 specimens of otitis media with effusion, 28 (28.9%) tested positive by both culture and PCR for M catarrhalis, H influenzae, or S pneumoniae. An additional 47 specimens (48%) were PCR positive/culture negative for these three bacterial species. Thus, 75 (77.3%) of the 97 specimens tested PCR positive for one or more of the three test organisms. The minimum number of bacterial genomic equivalents present in the average culture-negative ear was estimated to be greater than 10(4) based on dilutional experiments. The PCR-based assay systems can detect the presence of bacterial DNA in a significant percentage of culturally sterile middle ear effusions. While this finding is not proof of an active bacterial infectious process, the large number of bacterial genomic equivalents present in the ears is suggestive of an active process.

  9. From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen

    KAUST Repository

    Weynberg, Karen D.

    2015-12-08

    Disease is an increasing threat to reef-building corals. One of the few identified pathogens of coral disease is the bacterium Vibrio coralliilyticus. In Vibrio cholerae, infection by a bacterial virus (bacteriophage) results in the conversion of non-pathogenic strains to pathogenic strains and this can lead to cholera pandemics. Pathogenicity islands encoded in the V. cholerae genome play an important role in pathogenesis. Here we analyse five whole genome sequences of V. coralliilyticus to examine whether virulence is similarly driven by horizontally acquired elements. We demonstrate that bacteriophage genomes encoding toxin genes with homology to those found in pathogenic V. cholerae are integrated in V. coralliilyticus genomes. Virulence factors located on chromosomal pathogenicity islands also exist in some strains of V. coralliilyticus. The presence of these genetic signatures indicates virulence in V. coralliilyticus is driven by prophages and other horizontally acquired elements. Screening for pathogens of coral disease should target conserved regions in these elements.

  10. A pathogen-inducible patatin-like lipid acyl hydrolase facilitates fungal and bacterial host colonization in Arabidopsis.

    Science.gov (United States)

    La Camera, Sylvain; Geoffroy, Pierrette; Samaha, Hala; Ndiaye, Abdoulaye; Rahim, Gwendoline; Legrand, Michel; Heitz, Thierry

    2005-12-01

    Genes and proteins related to patatin, the major storage protein of potato tubers, have been identified in many plant species and shown to be induced by a variety of environmental stresses. The Arabidopsis patatin-like gene family (PLPs) comprises nine members, two of which (PLP2 and PLP7) are strongly induced in leaves challenged with fungal and bacterial pathogens. Here we show that accumulation of PLP2 protein in response to Botrytis cinerea or Pseudomonas syringae pv. tomato (avrRpt2) is dependent on jasmonic acid and ethylene signaling, but is not dependent on salicylic acid. Expression of a PLP2-green fluorescent protein (GFP) fusion protein and analysis of recombinant PLP2 indicates that PLP2 encodes a cytoplasmic lipid acyl hydrolase with wide substrate specificity. Transgenic plants with altered levels of PLP2 protein were generated and assayed for pathogen resistance. Plants silenced for PLP2 expression displayed enhanced resistance to B. cinerea, whereas plants overexpressing PLP2 were much more sensitive to this necrotrophic fungus. We also established a positive correlation between the level of PLP2 expression in transgenic plants and cell death or damage in response to paraquat treatment or infection by avirulent P. syringae. Interestingly, repression of PLP2 expression increased resistance to avirulent bacteria, while PLP2-overexpressing plants multiplied avirulent bacteria close to the titers reached by virulent bacteria. Collectively, the data indicate that PLP2-encoded lipolytic activity can be exploited by pathogens with different lifestyles to facilitate host colonization. In particular PLP2 potentiates plant cell death inflicted by Botrytis and reduces the efficiency of the hypersensitive response in restricting the multiplication of avirulent bacteria. Both effects are possibly mediated by providing fatty acid precursors of bioactive oxylipins.

  11. Vaccine strategies against bacterial pathogens in cystic fibrosis patients.

    Science.gov (United States)

    Le Moigne, V; Gaillard, J-L; Herrmann, J-L

    2016-02-01

    A large number of cystic fibrosis pathogens such as bacteria of the Burkholderia cepacia complex, Pseudomonas aeruginosa, or Mycobacterium abscessus are associated with complex therapeutic problems due to their inherent resistance to antibiotics. No vaccine is currently available against those pathogens. Vaccines are therefore crucial to combat these multidrug-resistant bacteria in specific clinical situations including cystic fibrosis. Various strategies may be considered to develop these vaccines. Similar virulence factors are expressed during the infection with various pathogens; they could thus be used as antigen to assess cross-protection. Many clinical trials are currently being conducted to try and develop a prophylactic treatment for patients presenting with cystic fibrosis. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  12. Camel Mastitis, associated Bacterial Pathogens and its impact on ...

    African Journals Online (AJOL)

    The present study was conducted between September 2006 and April 2007 with the aim of assessing the occurrence of camel mastitis and bacterial causes associated with it and evaluating Fat and Protein content of camel milk in Gewane district, Afar Regional State, Northeastern Ethiopia. Lactating camels which are ...

  13. Hijacking host cell highways: manipulation of the host actin cytoskeleton by obligate intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Punsiri M Colonne

    2016-09-01

    Full Text Available Intracellular bacterial pathogens replicate within eukaryotic cells and display unique adaptations that support key infection events including invasion, replication, immune evasion, and dissemination. From invasion to dissemination, all stages of the intracellular bacterial life cycle share the same three-dimensional cytosolic space containing the host cytoskeleton. For successful infection and replication, many pathogens hijack the cytoskeleton using effector proteins introduced into the host cytosol by specialized secretion systems. A subset of effectors contains eukaryotic-like motifs that mimic host proteins to exploit signaling and modify specific cytoskeletal components such as actin and microtubules. Cytoskeletal rearrangement promotes numerous events that are beneficial to the pathogen, including internalization of bacteria, subversion of cell intrinsic immunity, structural support for bacteria-containing vacuoles, altered vesicular trafficking, actin-dependent bacterial movement, and pathogen dissemination. This review highlights a diverse group of obligate intracellular bacterial pathogens that manipulate the host cytoskeleton to thrive within eukaryotic cells and discusses underlying molecular mechanisms that promote these dynamic host-pathogen interactions.

  14. COMPARATIVE ACTIVITY OF CECROPIN A AND POLYMYXIN B AGAINST FROG BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    Ermin Schadich

    2013-03-01

    Full Text Available The antimicrobial activity of two antimicrobial peptides, cecropin A and polymyxin B against different bacterial pathogens associated with bacterial dermatosepticemia, a fatal bacterial infectious disease of frogs was investigated. The peptides were tested in serial of concentrations (100-0.19 µg/ml for growth inhibition of seven pathogens: Aeromonas hydrophila, Chryseobacterium meningosepticum, Citrobacter freundii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis and Serratia liquefaciens. Their antimicrobial activity was compared with that of two antimicrobial peptides from frog skin, magainin 2 and aurein 2.1. Both cecropin A and polymyxin B, completely inhibited the growth of three pathogens: C. freundii, K. pneumoniae and P. aeruginosa at a concentration some sixteen times less than two skin peptides. Furthermore, cecropin A inhibited the growth of three pathogens resistant to the two skin peptides, A. hydrophila, C. meningosepticum and P. mirabilis. Polymyxin B also inhibited the growth of three pathogens resistant to the skin peptides, A. hydrophila, C. meningosepticum and S. liquefaciens. Cecropin A and polymyxin B have marked antibacterial activity against different frog bacterial pathogens indicating potential for therapeutic measures.Keywords: frogs, antimicrobial, bacteria, cecropin, polymyxin, resistance

  15. Hard ticks and their bacterial endosymbionts (or would be pathogens)

    Czech Academy of Sciences Publication Activity Database

    Ahantarig, A.; Trinachartvanit, W.; Baimai, V.; Grubhoffer, Libor

    2013-01-01

    Roč. 58, č. 5 (2013), s. 419-428 ISSN 0015-5632 Institutional support: RVO:60077344 Keywords : Ixodes ricinus * Candidatus Midichloria mitochondrii * Francisella-like endosymbionts * vector Ambylomma americanum * fever group Rickettsiae * Dermacentor and ersoni * spotted fever * borne pathogens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.145, year: 2013

  16. Cf-dependent early defence responses induced by avirulence proteins of the tomato pathogen : Cladosporium fulvum

    NARCIS (Netherlands)

    Jong, de C.F.

    2002-01-01

    The outcome of a plant-pathogen interaction is determined by both the presence of resistance ( R ) genes in the plant and matching avirulence ( Avr ) genes in the pathogen. According to the gene-for-gene concept, for a dominant

  17. The FUN of identifying gene function in bacterial pathogens; insights from Salmonella functional genomics.

    Science.gov (United States)

    Hammarlöf, Disa L; Canals, Rocío; Hinton, Jay C D

    2013-10-01

    The availability of thousands of genome sequences of bacterial pathogens poses a particular challenge because each genome contains hundreds of genes of unknown function (FUN). How can we easily discover which FUN genes encode important virulence factors? One solution is to combine two different functional genomic approaches. First, transcriptomics identifies bacterial FUN genes that show differential expression during the process of mammalian infection. Second, global mutagenesis identifies individual FUN genes that the pathogen requires to cause disease. The intersection of these datasets can reveal a small set of candidate genes most likely to encode novel virulence attributes. We demonstrate this approach with the Salmonella infection model, and propose that a similar strategy could be used for other bacterial pathogens. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. The Clavibacter michiganensis subsp. michiganensis-tomato interactome reveals the perception of pathogen by the host and suggests mechanisms of infection

    Energy Technology Data Exchange (ETDEWEB)

    Savidor, Alon [Tel Aviv University; Teper, [Tel Aviv University; Gartemann, KH [Tel Aviv University; Eichenlaub, R [Tel Aviv University; Chalupowicz, L [Tel Aviv University; Manulis-Sasson, S [Tel Aviv University; Barash, I [Tel Aviv University; Tews, H [Tel Aviv University; Mayer, K [Tel Aviv University; Giannone, Richard J [ORNL; Hettich, Robert {Bob} L [ORNL; Sessa, G [Tel Aviv University

    2012-01-01

    The Gram-positive bacterium Clavibacter michiganensis subsp. michiganensis (Cmm) causes wilt and canker disease of tomato (Solanum lycopersicum). Mechanisms of Cmm pathogenicity and tomato response to Cmm infection are not well understood. To explore the interaction between Cmm and tomato, multidimensional protein identification technology (MudPIT) and tandem mass spectrometry were used to analyze in vitro and in planta generated samples. The results show that during infection Cmm senses the plant environment, transmits signals, induces, and then secretes multiple hydrolytic enzymes, including serine proteases of the Pat-1, Ppa, and Sbt familes, the CelA, XysA, and NagA glycosyl hydrolases, and other cell wall-degrading enzymes. Tomato induction of pathogenesis-related (PR) proteins, LOX1, and other defense-related proteins during infection indicates that the plant senses the invading bacterium and mounts a basal defense response, although partial with some suppressed components including class III peroxidases and a secreted serine peptidase. The tomato ethylene-synthesizing enzyme ACC-oxidase was induced during infection with the wild-type Cmm but not during infection with an endophytic Cmm strain, identifying Cmm-triggered host synthesis of ethylene as an important factor in disease symptom development. The proteomic data were also used to improve Cmm genome annotation, and thousands of Cmm gene models were confirmed or expanded.

  19. O antigen modulates insect vector acquisition of the bacterial plant pathogen Xylella fastidiosa.

    Science.gov (United States)

    Rapicavoli, Jeannette N; Kinsinger, Nichola; Perring, Thomas M; Backus, Elaine A; Shugart, Holly J; Walker, Sharon; Roper, M Caroline

    2015-12-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. Inhibitory effect of Lactobacillus rhamnosus on pathogenic bacteria isolated from women with bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    Gita Eslami

    2014-06-01

    Full Text Available Background: Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. The purpose of this study is to investigate the inhibitory effect of Lactobacillus rhamnosus on pathogenic bacteria isolated from women with bacterial vaginosis, respectively.Materials and Methods: 96 samples from women with bacterial vaginosis discharge referred to health centers dependent Shahid Beheshti University in 91-92 were taken by a gynecologist with a dacron swab and put in sterile tubes containing TSB broth and Thioglycollate broth and were immediately sent to the lab location in cold chain for the next stages of investigation. From Thioglycollate and TSB medium was cultured on blood agar and EMB and Palkam and Differential diagnosis environments, and then incubated for 24 h at 37°C. Strains of Lactobacillus rhamnosus were cultured in MRSA environment and were transfered to the lab. After purification of pathogenic bacteria, MIC methods and antibiogram, Lactobacillus rhamnosus inhibitory effect on pathogenic bacteria is checked. Statistical analysis was done by SPSS software v.16.Results: The results of this study show the inhibitory effect of Lactobacillus rhamnosus on some pathogenic bacteria that cause bacterial vaginosis, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus agalactiae, Entrococcus, Listeria monocytogenes and E.Coli. Microscopic examination of stained smears of the large number of Lactobacillus and pathogenic bacteria showed reduced. The prevalence of abnormal vaginal discharge, history of drug use means of preventing pregnancy and douching, respectively, 61%, 55%, 42% and 13% respectively. Significant difference was observed between the use and non-use of IUD in women with bacterial vaginosis infection

  1. Bacterial endophytes from wild and ancient maize are able to suppress the fungal pathogen Sclerotinia homoeocarpa.

    Science.gov (United States)

    Shehata, H R; Lyons, E M; Jordan, K S; Raizada, M N

    2016-03-01

    The aim of this study was to determine if endophytes from wild and ancient Zea plants (corn family) have anti-fungal activities, specifically against the most important fungal pathogen (Sclerotinia homoeocarpa) of creeping bentgrass, a relative of Zea, used here as a model grass. A library of 190 bacterial endophytes from wild, ancient and modern Zea plants were tested for their ability to suppress S. homoeocarpa in vitro, followed by in planta testing of candidates using greenhouse trials. Three endophytes could suppress S. homoeocarpa, originating from wild maize and an ancient Mexican landrace, consistent with our hypothesis. 16S phylogenetic analysis and BOX-PCR DNA fingerprinting suggest that the anti-fungal endophytes are distinct strains of Burkholderia gladioli. One strain (3A12) was confirmed to colonize creeping bentgrass using green fluorescent protein (GFP) tagging. Evans blue vitality staining demonstrated that the bacterial endophytes exhibited fungicidal activities against the pathogen. The endophytes inhibited a wide spectrum of plant-associated fungi including diverse crop pathogens. The results support the hypothesis that wild and ancient Zea genotypes host bacterial endophytes that can control fungal pathogen(s). These results suggest that wild and ancient crops may be an unexplored reservoir of anti-fungal bacterial endophytes. © 2016 The Society for Applied Microbiology.

  2. The human-bacterial pathogen protein interaction networks of Bacillus anthracis, Francisella tularensis, and Yersinia pestis.

    Directory of Open Access Journals (Sweden)

    Matthew D Dyer

    2010-08-01

    Full Text Available Bacillus anthracis, Francisella tularensis, and Yersinia pestis are bacterial pathogens that can cause anthrax, lethal acute pneumonic disease, and bubonic plague, respectively, and are listed as NIAID Category A priority pathogens for possible use as biological weapons. However, the interactions between human proteins and proteins in these bacteria remain poorly characterized leading to an incomplete understanding of their pathogenesis and mechanisms of immune evasion.In this study, we used a high-throughput yeast two-hybrid assay to identify physical interactions between human proteins and proteins from each of these three pathogens. From more than 250,000 screens performed, we identified 3,073 human-B. anthracis, 1,383 human-F. tularensis, and 4,059 human-Y. pestis protein-protein interactions including interactions involving 304 B. anthracis, 52 F. tularensis, and 330 Y. pestis proteins that are uncharacterized. Computational analysis revealed that pathogen proteins preferentially interact with human proteins that are hubs and bottlenecks in the human PPI network. In addition, we computed modules of human-pathogen PPIs that are conserved amongst the three networks. Functionally, such conserved modules reveal commonalities between how the different pathogens interact with crucial host pathways involved in inflammation and immunity.These data constitute the first extensive protein interaction networks constructed for bacterial pathogens and their human hosts. This study provides novel insights into host-pathogen interactions.

  3. Detection of a pathogen shift among the pectolytic bacterial pathogens of potato in Washington State

    Science.gov (United States)

    Bacterial tuber soft rot, aerial stem rot and blackleg are significant diseases of potatoes in Washington State. These diseases are caused by Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, and Dickeya chrysanthemi, all characterized by the ability to produce pectolytic ...

  4. Photodynamic therapy induces an immune response against a bacterial pathogen

    Science.gov (United States)

    Huang, Ying-Ying; Tanaka, Masamitsu; Vecchio, Daniela; Garcia-Diaz, Maria; Chang, Julie; Morimoto, Yuji; Hamblin, Michael R

    2012-01-01

    Photodynamic therapy (PDT) employs the triple combination of photosensitizers, visible light and ambient oxygen. When PDT is used for cancer, it has been observed that both arms of the host immune system (innate and adaptive) are activated. When PDT is used for infectious disease, however, it has been assumed that the direct antimicrobial PDT effect dominates. Murine arthritis caused by methicillin-resistant Staphylococcus aureus in the knee failed to respond to PDT with intravenously injected Photofrin®. PDT with intra-articular Photofrin produced a biphasic dose response that killed bacteria without destroying host neutrophils. Methylene blue was the optimum photosensitizer to kill bacteria while preserving neutrophils. We used bioluminescence imaging to noninvasively monitor murine bacterial arthritis and found that PDT with intra-articular methylene blue was not only effective, but when used before infection, could protect the mice against a subsequent bacterial challenge. The data emphasize the importance of considering the host immune response in PDT for infectious disease. PMID:22882222

  5. Analysis of bacterial communities and bacterial pathogens in a biogas plant by the combination of ethidium monoazide, PCR and Ion Torrent sequencing.

    Science.gov (United States)

    Luo, Gang; Angelidaki, Irini

    2014-09-01

    The present study investigated the changes of bacterial community composition including bacterial pathogens along a biogas plant, i.e. from the influent, to the biogas reactor and to the post-digester. The effects of post-digestion temperature and time on the changes of bacterial community composition and bacterial pathogens were also studied. Microbial analysis was made by Ion Torrent sequencing of the PCR amplicons from ethidium monoazide treated samples, and ethidium monoazide was used to cleave DNA from dead cells and exclude it from PCR amplification. Both similarity and taxonomic analysis showed that the bacterial community composition in the influent was changed after anaerobic digestion. Firmicutes were dominant in all the samples, while Proteobacteria decreased in the biogas reactor compared with the influent. Variations of bacterial community composition in the biogas reactor with time were also observed. This could be attributed to varying composition of the influent. Batch experiments showed that the methane recovery from the digested residues (obtained from biogas reactor) was mainly related with post-digestion temperature. However, post-digestion time rather than temperature had a significant effect on the changes of bacterial community composition. The changes of bacterial community composition were also reflected in the changes of relative abundance of bacterial pathogens. The richness and relative abundance of bacterial pathogens were reduced after anaerobic digestion in the biogas reactor. It was found in batch experiments that bacterial pathogens showed the highest relative abundance and richness after 30 days' post-digestion. Streptococcus bovis was found in all the samples. Our results showed that special attention should be paid to the post-digestion since the increase in relative abundance of bacterial pathogens after post-digestion might reflect regrowth of bacterial pathogens and limit biosolids disposal vectors. Copyright © 2014 Elsevier

  6. Viral and Bacterial Pathogens in Bovine Respiratory Disease in Finland

    Directory of Open Access Journals (Sweden)

    Soveri T

    2004-12-01

    Full Text Available Pathogens causing bovine respiratory tract disease in Finland were investigated. Eighteen cattle herds with bovine respiratory disease were included. Five diseased calves from each farm were chosen for closer examination and tracheobronchial lavage. Blood samples were taken from the calves at the time of the investigation and from 86 calves 3–4 weeks later. In addition, 6–10 blood samples from animals of different ages were collected from each herd, resulting in 169 samples. Serum samples were tested for antibodies to bovine parainfluenza virus-3 (PIV-3, bovine respiratory syncytial virus (BRSV, bovine coronavirus (BCV, bovine adenovirus-3 (BAV-3 and bovine adenovirus-7 (BAV-7. About one third of the samples were also tested for antibodies to bovine virus diarrhoea virus (BVDV with negative results. Bacteria were cultured from lavage fluid and in vitro susceptibility to selected antimicrobials was tested. According to serological findings, PIV-3, BAV-7, BAV-3, BCV and BRSV are common pathogens in Finnish cattle with respiratory problems. A titre rise especially for BAV-7 and BAV-3, the dual growth of Mycoplasma dispar and Pasteurella multocida, were typical findings in diseased calves. Pasteurella sp. strains showed no resistance to tested antimicrobials. Mycoplasma bovis and Mannheimia haemolytica were not found.

  7. Plasticity in early immune evasion strategies of a bacterial pathogen.

    Science.gov (United States)

    Bernard, Quentin; Smith, Alexis A; Yang, Xiuli; Koci, Juraj; Foor, Shelby D; Cramer, Sarah D; Zhuang, Xuran; Dwyer, Jennifer E; Lin, Yi-Pin; Mongodin, Emmanuel F; Marques, Adriana; Leong, John M; Anguita, Juan; Pal, Utpal

    2018-04-17

    Borrelia burgdorferi is one of the few extracellular pathogens capable of establishing persistent infection in mammals. The mechanisms that sustain long-term survival of this bacterium are largely unknown. Here we report a unique innate immune evasion strategy of B. burgdorferi , orchestrated by a surface protein annotated as BBA57, through its modulation of multiple spirochete virulent determinants. BBA57 function is critical for early infection but largely redundant for later stages of spirochetal persistence, either in mammals or in ticks. The protein influences host IFN responses as well as suppresses multiple host microbicidal activities involving serum complement, neutrophils, and antimicrobial peptides. We also discovered a remarkable plasticity in BBA57-mediated spirochete immune evasion strategy because its loss, although resulting in near clearance of pathogens at the inoculum site, triggers nonheritable adaptive changes that exclude detectable nucleotide alterations in the genome but incorporate transcriptional reprograming events. Understanding the malleability in spirochetal immune evasion mechanisms that ensures their host persistence is critical for the development of novel therapeutic and preventive approaches to combat long-term infections like Lyme borreliosis.

  8. Protection of Tomato Seedlings against Infection by Pseudomonas syringae pv. Tomato by Using the Plant Growth-Promoting Bacterium Azospirillum brasilense†

    Science.gov (United States)

    Bashan, Yoav; de-Bashan, Luz E.

    2002-01-01

    Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (107 versus 105 CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (107 versus 106 CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (105 to 106 CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications

  9. Evaluation of PCR based assays for the improvement of proportion estimation of bacterial and viral pathogens in diarrheal surveillance

    Directory of Open Access Journals (Sweden)

    Hongxia eGuan

    2016-03-01

    Full Text Available AbstractDiarrhea can be caused by a variety of bacterial, viral and parasitic organisms. Laboratory diagnosis is essential in the pathogen-specific burden assessment. In the pathogen spectrum monitoring in the diarrheal surveillance, culture methods are commonly used for the bacterial pathogens’ detection whereas nucleic acid based amplification, the non-cultural methods are used for the viral pathogens. Different methodology may cause the inaccurate pathogen spectrum for the bacterial pathogens because of their different culture abilities with the different media, and for the comparison of bacterial vs. viral pathogens. The application of nucleic acid-based methods in the detection of viral and bacterial pathogens will likely increase the number of confirmed positive diagnoses, and will be comparable since all pathogens will be detected based on the same nucleic acid extracts from the same sample. In this study, bacterial pathogens, including diarrheagenic Escherichia coli (DEC, Salmonella spp., Shigella spp., Vibrio parahaemolyticus and V. cholerae, were detected in 334 diarrheal samples by PCR-based methods using nucleic acid extracted from stool samples and associated enrichment cultures. A protocol was established to facilitate the consistent identification of bacterial pathogens in diarrheal patients. Five common enteric viruses were also detected by RT-PCR, including rotavirus, sapovirus, norovirus (I and II, human astrovirus, and enteric adenovirus. Higher positive rates were found for the bacterial pathogens, showing the lower proportion estimation if only using culture methods. This application will improve the quality of bacterial diarrheagenic pathogen survey, providing more accurate information pertaining to the pathogen spectrum associated with finding of food safety problems and disease burden evaluation.

  10. Multiplex PCR assay for simultaneous detection of six major bacterial pathogens of rice.

    Science.gov (United States)

    Cui, Z; Ojaghian, M R; Tao, Z; Kakar, K U; Zeng, J; Zhao, W; Duan, Y; Vera Cruz, C M; Li, B; Zhu, B; Xie, G

    2016-05-01

    The aim of this study was to develop a multiplex PCR (mPCR) assay for rapid, sensitive and simultaneous detection of six important rice pathogens: Xanthomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, Pseudomonas fuscovaginae, Burkholderia glumae, Burkholderia gladioli and Acidovorax avenae subsp. avenae. Specific primers were designed through a bioinformatics pipeline. Sensitivity of detection was established using both traditional PCR and quantitative real-time PCR on isolated DNA and on bacterial cells both in vitro and in simulated diseased seeds and the parameters were optimized for an mPCR assay. A total of 150 bacterial strains were tested for specificity. The mPCR assay accurately predicted the presence of pathogens among 44 symptomatic and asymptomatic rice seed, sheath and leaf samples. This study confirmed that this mPCR assay is a rapid, reliable and simple tool for the simultaneous detection of six important rice bacterial pathogens. This study is the first report of a method allowing simultaneous detection of six major rice pathogens. The ability to use crude extracts from plants without bacterial isolation or DNA extraction enhances the value of this mPCR technology for rapid detection and aetiological/epidemiological studies. © 2016 The Society for Applied Microbiology.

  11. A Bacterial Pathogen uses Distinct Type III Secretion Systems to Alternate between Host Kingdom

    Science.gov (United States)

    Gram-negative bacterial pathogens of eukaryotes often secrete proteins directly into host cells via a needle-like protein channel called a ‘type III secretion system’ (T3SS). Bacteria that are adapted to either animal or plant hosts use phylogenetically distinct T3SSs for secreting proteins. Here, ...

  12. Analysis of apple (Malus) responses to bacterial pathogens using an oligo microarray

    Science.gov (United States)

    Fire blight is a devastating disease of apple (Malus x domestica) caused by the bacterial pathogen Erwinia amylovora (Ea). When infiltrated into host leaves, Ea induces reactions similar to a hypersensitive response (HR). Type III (T3SS) associated effectors, especially DspA/E, are suspected to ha...

  13. A bacterial pathogen uses distinct type III secretion systems to alternate between host kingdoms

    Science.gov (United States)

    Plant and animal-pathogenic bacteria utilize phylogenetically distinct type III secretion systems (T3SS) that produce needle-like injectisomes or pili for the delivery of effector proteins into host cells. Pantoea stewartii subsp. stewartii (Pnss), the causative agent of Stewart’s bacterial wilt and...

  14. Bacterial pathogens of acute sinusitis in the osteomeatal complex during common colds and wellness.

    Science.gov (United States)

    Han, Joseph K; Hendley, J Owen; Winther, Birgit

    2011-01-01

    Pathogenic bacteria have been cultured from the osteomeatal complex (OMC) in one-third of adults with apparent acute bacterial sinusitis; however, it is not known whether bacteria are present in the OMC during uncomplicated viral colds in adults. Adult volunteers were recruited for a study during wellness and at the time of acute common cold. Swab cultures were obtained from the OMC and from the nasopharynx by 2 routes (through the nose and through the mouth). Swab eluates were inoculated on selective agars to detect S. pneumoniae, H. influenzae, and M. catarrhalis. Bacterial pathogens were detected in the OMC more frequently during common colds than during wellness (31% vs 8%, p OMC were always present in the nasopharynx of the subject. Bacterial pathogens are present in the OMC in a subgroup of adult patients with uncomplicated upper respiratory illness/common cold. The nasopharynx appears to be the reservoir for bacterial pathogens in the OMC. Copyright © 2011 American Rhinologic Society-American Academy of Otolaryngic Allergy, LLC.

  15. The effect of nitrogen on disease development and gene expression in bacterial and fungal plant pathogens

    NARCIS (Netherlands)

    Snoeijers, S.S.; Pérez-García, A.; Joosten, M.H.A.J.; Wit, de P.J.G.M.

    2000-01-01

    Successful colonisation of plants by pathogens requires efficient utilisation of nutrient resources available in host tissues. Several bacterial and fungal genes are specifically induced during pathogenesis and under nitrogen-limiting conditions in vitro. This suggests that a nitrogen-limiting

  16. Chemical inhibitors of the type three secretion system: disarming bacterial pathogens.

    Science.gov (United States)

    Duncan, Miles C; Linington, Roger G; Auerbuch, Victoria

    2012-11-01

    The recent and dramatic rise of antibiotic resistance among bacterial pathogens underlies the fear that standard treatments for infectious disease will soon be largely ineffective. Resistance has evolved against nearly every clinically used antibiotic, and in the near future, we may be hard-pressed to treat bacterial infections previously conquered by "magic bullet" drugs. While traditional antibiotics kill or slow bacterial growth, an important emerging strategy to combat pathogens seeks to block the ability of bacteria to harm the host by inhibiting bacterial virulence factors. One such virulence factor, the type three secretion system (T3SS), is found in over two dozen Gram-negative pathogens and functions by injecting effector proteins directly into the cytosol of host cells. Without T3SSs, many pathogenic bacteria are unable to cause disease, making the T3SS an attractive target for novel antimicrobial drugs. Interdisciplinary efforts between chemists and microbiologists have yielded several T3SS inhibitors, including the relatively well-studied salicylidene acylhydrazides. This review highlights the discovery and characterization of T3SS inhibitors in the primary literature over the past 10 years and discusses the future of these drugs as both research tools and a new class of therapeutic agents.

  17. Bacterial siderophores efficiently provide iron to iron-starved tomato plants in hydroponics culture

    OpenAIRE

    Radzki, W.; Gutierrez Ma?ero, F. J.; Algar, E.; Lucas Garc?a, J. A.; Garc?a-Villaraco, A.; Ramos Solano, B.

    2013-01-01

    Iron is one of the essential elements for a proper plant development. Providing plants with an accessible form of iron is crucial when it is scant or unavailable in soils. Chemical chelates are the only current alternative and are highly stable in soils, therefore, posing a threat to drinking water. The aim of this investigation was to quantify siderophores produced by two bacterial strains and to determine if these bacterial siderophores would palliate chlorotic symptoms of iron-starved toma...

  18. Quorum-Sensing Blockade As A Strategy for Enhancing Host Defences Against Bacterial Pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    is likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi......Conventional antibiotics target the growth and the basal life processes of bacteria leading to growth arrest and cell death. The selective force that is inherently linked to this mode of action eventually selects out antibiotic-resistant variants. The most obvious alternative to antibiotic......-mediated killing or growth inhibition would be to attenuate the bacteria with respect to pathogenicity. The realization that Pseudomonas aeruginosa, and a number of other pathogens, controls much of their virulence arsenal by means of extracellular signal molecules in a process denoted quorum sensing (QS) gave...

  19. The role and regulation of catalase in respiratory tract opportunistic bacterial pathogens.

    Science.gov (United States)

    Eason, Mia M; Fan, Xin

    2014-09-01

    Respiratory tract bacterial pathogens are the etiologic agents of a variety of illnesses. The ability of these bacteria to cause disease is imparted through survival within the host and avoidance of pathogen clearance by the immune system. Respiratory tract pathogens are continually bombarded by reactive oxygen species (ROS), which may be produced by competing bacteria, normal metabolic function, or host immunological responses. In order to survive and proliferate, bacteria have adapted defense mechanisms to circumvent the effects of ROS. Bacteria employ the use of anti-oxidant enzymes, catalases and catalase-peroxidases, to relieve the effects of the oxidative stressors to which they are continually exposed. The decomposition of ROS has been shown to provide favorable conditions in which respiratory tract opportunistic bacterial pathogens such as Haemophilus influenzae, Mycobacterium tuberculosis, Legionella pneumophila, and Neisseria meningitidis are able to withstand exposure to highly reactive molecules and yet survive. Bacteria possessing mutations in the catalase gene have a decreased survival rate, yet may be able to compensate for the lack of catalatic activity if peroxidatic activity is present. An incomplete knowledge of the mechanisms by which catalase and catalase-peroxidases are regulated still persists, however, in some bacterial species, a regulatory factor known as OxyR has been shown to either up-regulate or down-regulate catalase gene expression. Yet, more research is still needed to increase the knowledge base in relation to this enzyme class. As with this review, we focus on major respiratory tract opportunistic bacterial pathogens in order to elucidate the function and regulation of catalases. The importance of the research could lead to the development of novel treatments against respiratory bacterial infections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Detection of respiratory bacterial pathogens causing atypical pneumonia by multiplex Lightmix®RT-PCR.

    Science.gov (United States)

    Wagner, Karoline; Springer, Burkard; Imkamp, Frank; Opota, Onya; Greub, Gilbert; Keller, Peter M

    2018-04-01

    Pneumonia is a severe infectious disease. In addition to common viruses and bacterial pathogens (e.g. Streptococcus pneumoniae), fastidious respiratory pathogens like Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella spp. can cause severe atypical pneumonia. They do not respond to penicillin derivatives, which may cause failure of antibiotic empirical therapy. The same applies for infections with B. pertussis and B. parapertussis, the cause of pertussis disease, that may present atypically and need to be treated with macrolides. Moreover, these fastidious bacteria are difficult to identify by culture or serology, and therefore often remain undetected. Thus, rapid and accurate identification of bacterial pathogens causing atypical pneumonia is crucial. We performed a retrospective method evaluation study to evaluate the diagnostic performance of the new, commercially available Lightmix ® multiplex RT-PCR assay that detects these fastidious bacterial pathogens causing atypical pneumonia. In this retrospective study, 368 clinical respiratory specimens, obtained from patients suffering from atypical pneumonia that have been tested negative for the presence of common agents of pneumonia by culture and viral PCR, were investigated. These clinical specimens have been previously characterized by singleplex RT-PCR assays in our diagnostic laboratory and were used to evaluate the diagnostic performance of the respiratory multiplex Lightmix ® RT-PCR. The multiplex RT-PCR displayed a limit of detection between 5 and 10 DNA copies for different in-panel organisms and showed identical performance characteristics with respect to specificity and sensitivity as in-house singleplex RT-PCRs for pathogen detection. The Lightmix ® multiplex RT-PCR assay represents a low-cost, time-saving and accurate diagnostic tool with high throughput potential. The time-to-result using an automated DNA extraction device for respiratory specimens followed by multiplex RT-PCR detection was

  1. Bacterial-like PPP protein phosphatases: novel sequence alterations in pathogenic eukaryotes and peculiar features of bacterial sequence similarity.

    Science.gov (United States)

    Kerk, David; Uhrig, R Glen; Moorhead, Greg B

    2013-01-01

    Reversible phosphorylation is a widespread modification affecting the great majority of eukaryotic cellular proteins, and whose effects influence nearly every cellular function. Protein phosphatases are increasingly recognized as exquisitely regulated contributors to these changes. The PPP (phosphoprotein phosphatase) family comprises enzymes, which catalyze dephosphorylation at serine and threonine residues. Nearly a decade ago, "bacterial-like" enzymes were recognized with similarity to proteins from various bacterial sources: SLPs (Shewanella-like phosphatases), RLPHs (Rhizobiales-like phosphatases), and ALPHs (ApaH-like phosphatases). A recent article from our laboratory appearing in Plant Physiology characterizes their extensive organismal distribution, abundance in plant species, predicted subcellular localization, motif organization, and sequence evolution. One salient observation is the distinct evolutionary trajectory followed by SLP genes and proteins in photosynthetic eukaryotes vs. animal and plant pathogens derived from photosynthetic ancestors. We present here a closer look at sequence data that emphasizes the distinctiveness of pathogen SLP proteins and that suggests that they might represent novel drug targets. A second observation in our original report was the high degree of similarity between the bacterial-like PPPs of eukaryotes and closely related proteins of the "eukaryotic-like" phyla Myxococcales and Planctomycetes. We here reflect on the possible implications of these observations and their importance for future research.

  2. Public health genomics and the new molecular epidemiology of bacterial pathogens.

    Science.gov (United States)

    Gilmour, M W; Graham, M; Reimer, A; Van Domselaar, G

    2013-01-01

    Laboratory methods that can unambiguously fingerprint pathogenic microbes are needed to investigate the transmission of human infectious diseases from diverse sources, such as from the community, from the environment, within hospitals, or from contaminated food or water sources. Public health investigations currently rely on laboratory subtyping methods that ultimately provide only a fraction of the total genetic information of a pathogen, and although there is widespread success using existing subtyping methods, they do not always provide sufficient evidence to link disease cases together into outbreaks or to link these human cases to the culprit source. Alternatively, whole-genome sequencing of bacterial pathogens provides an unabridged examination of the genetic content of individual pathogen isolates, enabling public health laboratories to benefit from comparative analyses of total genetic content. In this context, whole-genome sequencing represents the ultimate epidemiological typing method - a universally applicable, highly detailed typing platform capable of providing the entire genetic blueprint of a pathogen and distinguishing strains to the single nucleotide level. These new genomic methods, if implemented within existing public health laboratory response programs, promise to revolutionize the ability of the laboratory to provide information and evidence on the evolution, transmission and virulence for bacterial pathogens - and this revolution is launching the new field of 'genomicepidemiology'. Copyright © 2013 S. Karger AG, Basel.

  3. Intracellular phase for an extracellular bacterial pathogen: MgtC shows the way

    Directory of Open Access Journals (Sweden)

    Audrey Bernut

    2015-08-01

    Full Text Available Pseudomonas aeruginosa is an extracellular pathogen known to impair host phagocytic functions. However, our recent results identify MgtC as a novel actor in P. aeruginosa virulence, which plays a role in an intramacrophage phase of this pathogen. In agreement with its intracellular function, P. aeruginosa mgtC gene expression is strongly induced when the bacteria reside within macrophages. MgtC was previously known as a horizontally-acquired virulence factor important for multiplication inside macrophages in several intracellular bacterial pathogens. MgtC thus provides a singular example of a virulence determinant that subverts macrophages both in intracellular and extracellular pathogens. Moreover, we demonstrate that P. aeru-ginosa MgtC is required for optimal growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens and, under Mg2+ limitation, P. aeruginosaMgtC prevents biofilm formation. We propose that MgtC has a similar function in intracellular and extracellular pathogens, which contributes to macrophage resistance and fine-tune adaptation to the host in relation to the different bacterial lifestyles. MgtC thus appears as an attractive target for antivirulence strategies and our work provides a natural peptide as MgtC antagonist, which paves the way for the development of MgtC inhibitors.

  4. Development of a Selective Medium for the Fungal Pathogen Fusarium graminearum Using Toxoflavin Produced by the Bacterial Pathogen Burkholderia glumae

    Directory of Open Access Journals (Sweden)

    Boknam Jung

    2013-12-01

    Full Text Available The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

  5. The host-encoded Heme Regulated Inhibitor (HRI facilitates virulence-associated activities of bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Niraj Shrestha

    Full Text Available Here we show that cells lacking the heme-regulated inhibitor (HRI are highly resistant to infection by bacterial pathogens. By examining the infection process in wild-type and HRI null cells, we found that HRI is required for pathogens to execute their virulence-associated cellular activities. Specifically, unlike wild-type cells, HRI null cells infected with the gram-negative bacterial pathogen Yersinia are essentially impervious to the cytoskeleton-damaging effects of the Yop virulence factors. This effect is due to reduced functioning of the Yersinia type 3 secretion (T3S system which injects virulence factors directly into the host cell cytosol. Reduced T3S activity is also observed in HRI null cells infected with the bacterial pathogen Chlamydia which results in a dramatic reduction in its intracellular proliferation. We go on to show that a HRI-mediated process plays a central role in the cellular infection cycle of the Gram-positive pathogen Listeria. For this pathogen, HRI is required for the post-invasion trafficking of the bacterium to the infected host cytosol. Thus by depriving Listeria of its intracellular niche, there is a highly reduced proliferation of Listeria in HRI null cells. We provide evidence that these infection-associated functions of HRI (an eIF2α kinase are independent of its activity as a regulator of protein synthesis. This is the first report of a host factor whose absence interferes with the function of T3S secretion and cytosolic access by pathogens and makes HRI an excellent target for inhibitors due to its broad virulence-associated activities.

  6. Bacterial genomics reveal the complex epidemiology of an emerging pathogen in arctic and boreal ungulates

    Science.gov (United States)

    Forde, Taya L.; Orsel, Karin; Zadoks, Ruth N.; Biek, Roman; Adams, Layne G.; Checkley, Sylvia L.; Davison, Tracy; De Buck, Jeroen; Dumond, Mathieu; Elkin, Brett T.; Finnegan, Laura; Macbeth, Bryan J.; Nelson, Cait; Niptanatiak, Amanda; Sather, Shane; Schwantje, Helen M.; van der Meer, Frank; Kutz, Susan J.

    2016-01-01

    Northern ecosystems are currently experiencing unprecedented ecological change, largely driven by a rapidly changing climate. Pathogen range expansion, and emergence and altered patterns of infectious disease, are increasingly reported in wildlife at high latitudes. Understanding the causes and consequences of shifting pathogen diversity and host-pathogen interactions in these ecosystems is important for wildlife conservation, and for indigenous populations that depend on wildlife. Among the key questions are whether disease events are associated with endemic or recently introduced pathogens, and whether emerging strains are spreading throughout the region. In this study, we used a phylogenomic approach to address these questions of pathogen endemicity and spread for Erysipelothrix rhusiopathiae, an opportunistic multi-host bacterial pathogen associated with recent mortalities in arctic and boreal ungulate populations in North America. We isolated E. rhusiopathiae from carcasses associated with large-scale die-offs of muskoxen in the Canadian Arctic Archipelago, and from contemporaneous mortality events and/or population declines among muskoxen in northwestern Alaska and caribou and moose in western Canada. Bacterial genomic diversity differed markedly among these locations; minimal divergence was present among isolates from muskoxen in the Canadian Arctic, while in caribou and moose populations, strains from highly divergent clades were isolated from the same location, or even from within a single carcass. These results indicate that mortalities among northern ungulates are not associated with a single emerging strain of E. rhusiopathiae, and that alternate hypotheses need to be explored. Our study illustrates the value and limitations of bacterial genomic data for discriminating between ecological hypotheses of disease emergence, and highlights the importance of studying emerging pathogens within the broader context of environmental and host factors.

  7. Bacterial Genomics Reveal the Complex Epidemiology of an Emerging Pathogen in Arctic and Boreal Ungulates.

    Science.gov (United States)

    Forde, Taya L; Orsel, Karin; Zadoks, Ruth N; Biek, Roman; Adams, Layne G; Checkley, Sylvia L; Davison, Tracy; De Buck, Jeroen; Dumond, Mathieu; Elkin, Brett T; Finnegan, Laura; Macbeth, Bryan J; Nelson, Cait; Niptanatiak, Amanda; Sather, Shane; Schwantje, Helen M; van der Meer, Frank; Kutz, Susan J

    2016-01-01

    Northern ecosystems are currently experiencing unprecedented ecological change, largely driven by a rapidly changing climate. Pathogen range expansion, and emergence and altered patterns of infectious disease, are increasingly reported in wildlife at high latitudes. Understanding the causes and consequences of shifting pathogen diversity and host-pathogen interactions in these ecosystems is important for wildlife conservation, and for indigenous populations that depend on wildlife. Among the key questions are whether disease events are associated with endemic or recently introduced pathogens, and whether emerging strains are spreading throughout the region. In this study, we used a phylogenomic approach to address these questions of pathogen endemicity and spread for Erysipelothrix rhusiopathiae , an opportunistic multi-host bacterial pathogen associated with recent mortalities in arctic and boreal ungulate populations in North America. We isolated E. rhusiopathiae from carcasses associated with large-scale die-offs of muskoxen in the Canadian Arctic Archipelago, and from contemporaneous mortality events and/or population declines among muskoxen in northwestern Alaska and caribou and moose in western Canada. Bacterial genomic diversity differed markedly among these locations; minimal divergence was present among isolates from muskoxen in the Canadian Arctic, while in caribou and moose populations, strains from highly divergent clades were isolated from the same location, or even from within a single carcass. These results indicate that mortalities among northern ungulates are not associated with a single emerging strain of E. rhusiopathiae , and that alternate hypotheses need to be explored. Our study illustrates the value and limitations of bacterial genomic data for discriminating between ecological hypotheses of disease emergence, and highlights the importance of studying emerging pathogens within the broader context of environmental and host factors.

  8. A Window of Opportunity to Control the Bacterial Pathogen Pseudomonas aeruginosa Combining Antibiotics and Phages

    Science.gov (United States)

    Torres-Barceló, Clara; Arias-Sánchez, Flor I.; Vasse, Marie; Ramsayer, Johan

    2014-01-01

    The evolution of antibiotic resistance in bacteria is a global concern and the use of bacteriophages alone or in combined therapies is attracting increasing attention as an alternative. Evolutionary theory predicts that the probability of bacterial resistance to both phages and antibiotics will be lower than to either separately, due for example to fitness costs or to trade-offs between phage resistance mechanisms and bacterial growth. In this study, we assess the population impacts of either individual or combined treatments of a bacteriophage and streptomycin on the nosocomial pathogen Pseudomonas aeruginosa. We show that combining phage and antibiotics substantially increases bacterial control compared to either separately, and that there is a specific time delay in antibiotic introduction independent of antibiotic dose, that minimizes both bacterial density and resistance to either antibiotics or phage. These results have implications for optimal combined therapeutic approaches. PMID:25259735

  9. Distribution of indigenous bacterial pathogens and potential pathogens associated with roof-harvested rainwater.

    Science.gov (United States)

    Dobrowsky, P H; De Kwaadsteniet, M; Cloete, T E; Khan, W

    2014-04-01

    The harvesting of rainwater is gaining acceptance among many governmental authorities in countries such as Australia, Germany, and South Africa, among others. However, conflicting reports on the microbial quality of harvested rainwater have been published. To monitor the presence of potential pathogenic bacteria during high-rainfall periods, rainwater from 29 rainwater tanks was sampled on four occasions (during June and August 2012) in a sustainable housing project in Kleinmond, South Africa. This resulted in the collection of 116 harvested rainwater samples in total throughout the sampling period. The identities of the dominant, indigenous, presumptive pathogenic isolates obtained from the rainwater samples throughout the sampling period were confirmed through universal 16S rRNA PCR, and the results revealed that Pseudomonas (19% of samples) was the dominant genus isolated, followed by Aeromonas (16%), Klebsiella (11%), and Enterobacter (9%). PCR assays employing genus-specific primers also confirmed the presence of Aeromonas spp. (16%), Klebsiella spp. (47%), Legionella spp. (73%), Pseudomonas spp. (13%), Salmonella spp. (6%), Shigella spp. (27%), and Yersinia spp. (28%) in the harvested rainwater samples. In addition, on one sampling occasion, Giardia spp. were detected in 25% of the eight tank water samples analyzed. This study highlights the diverse array of pathogenic bacteria that persist in harvested rainwater during high-rainfall periods. The consumption of untreated harvested rainwater could thus pose a potential significant health threat to consumers, especially children and immunocompromised individuals, and it is recommended that harvested rainwater be treated for safe usage as an alternative water source.

  10. Clinical and pathogenic analysis of 507 children with bacterial meningitis in Beijing, 2010-2014.

    Science.gov (United States)

    Guo, Ling-Yun; Zhang, Zhi-Xiao; Wang, Xi; Zhang, Ping-Ping; Shi, Wei; Yao, Kai-Hu; Liu, Lin-Lin; Liu, Gang; Yang, Yong-Hong

    2016-09-01

    To explore the clinical characteristics and analyze the pathogens of bacterial meningitis in children. Bacterial meningitis cases occurring from January 2010 through December 2014 at Beijing Children's Hospital were reviewed retrospectively. The records of all patients, including data on clinical features and laboratory information, were obtained and analyzed. In total, the cases of 507 pediatric patients seen over a 5-year period were analyzed; 220 of these cases were etiologically confirmed. These patients were classified into four age groups: 29 days to 1 year (n=373, 73.6%), 1-3 years (n=61, 12.0%), 3-6 years (n=41, 8.1%), and >6 years (n=32, 6.3%). The main pathogens identified in this study were Streptococcus pneumoniae (n=73, 33.2%), Escherichia coli (n=24, 10.9%), Enterococcus (n=22, 10.0%), and group B Streptococcus (n=18, 8.2%). All Gram-positive bacteria were sensitive to vancomycin and linezolid. All Gram-negative bacteria were sensitive to meropenem. The total non-susceptibility rate of S. pneumoniae to penicillin was 47.6% (20/42). The resistance rates to ceftriaxone, cefepime, and ceftazidime were 75% (9/12), 55.6% (5/9), and 40% (4/10), respectively. The main pathogen of bacterial meningitis in this study was S. pneumoniae. The antibiotic resistance rates among children with bacterial meningitis are of serious concern. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  11. The BER necessities: the repair of DNA damage in human-adapted bacterial pathogens.

    Science.gov (United States)

    van der Veen, Stijn; Tang, Christoph M

    2015-02-01

    During colonization and disease, bacterial pathogens must survive the onslaught of the host immune system. A key component of the innate immune response is the generation of reactive oxygen and nitrogen species by phagocytic cells, which target and disrupt pathogen molecules, particularly DNA, and the base excision repair (BER) pathway is the most important mechanism for the repair of such oxidative DNA damage. In this Review, we discuss how the human-specific pathogens Mycobacterium tuberculosis, Helicobacter pylori and Neisseria meningitidis have evolved specialized mechanisms of DNA repair, particularly their BER pathways, compared with model organisms such as Escherichia coli. This specialization in DNA repair is likely to reflect the distinct niches occupied by these important human pathogens in the host.

  12. Bottlenecks in the transmission of antibiotic resistance from natural ecosystems to human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Jose L Martinez

    2012-01-01

    Full Text Available It is generally accepted that resistance genes acquired by human pathogens trough horizontal gene transfer have been originated in environmental, non pathogenic bacteria. As the consequence, there exists an increasing concern on the role that natural, non-clinical ecosystems, may play on the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance upon their expression in a heterologous host is much larger than what is actually found in human pathogens. Along the review, the role that different processes as founder effect, ecological connectivity, fitness costs or second-order selection may have on the establishment of a specific resistance determinant in the population of bacterial pathogens is analysed.

  13. Shotgun metagenomic sequencing reveals freshwater beach sands as reservoir of bacterial pathogens.

    Science.gov (United States)

    Mohiuddin, Mahi M; Salama, Yasser; Schellhorn, Herb E; Golding, G Brian

    2017-05-15

    Recreational waters and adjacent beach sands harbor complex microbial communities which may contain human pathogens that cannot be detected by conventional methods. Here, we investigate the diversity of bacterial populations inhabiting four freshwater beaches of the Great Lakes region using shotgun metagenomic sequencing approach. Our analysis suggests that average taxonomic richness and alpha diversity are significantly higher (P beach sands compared to the corresponding water environments. Compared to the water environments, beach sands harbored taxa from a more diverse range of phyla, including a higher proportion of sequences from unclassified phyla. Unique phyla were also identified in sand which included species from Aquificae, Candidatus Microgenomates, Latescibacteria, and Candidatus Aminicenantes. Sequences originating from pathogens were detected in both sand and water, with some pathogens enriched in both environments. Both lakes exhibited similar community composition suggesting that geographic location did not appear to have any major impact on bacterial diversity. These findings reveal the diversity of bacterial communities of freshwater beaches and highlight the importance of monitoring pathogens in recreational beaches, especially in the sand environment of these beaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Development of Quorum-Based Anti-Virulence Therapeutics Targeting Gram-Negative Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Wen Shan Yew

    2013-08-01

    Full Text Available Quorum sensing is a cell density-dependent signaling phenomenon used by bacteria for coordination of population-wide phenotypes, such as expression of virulence genes, antibiotic resistance and biofilm formation. Lately, disruption of bacterial communication has emerged as an anti-virulence strategy with enormous therapeutic potential given the increasing incidences of drug resistance in pathogenic bacteria. The quorum quenching therapeutic approach promises a lower risk of resistance development, since interference with virulence generally does not affect the growth and fitness of the bacteria and, hence, does not exert an associated selection pressure for drug-resistant strains. With better understanding of bacterial communication networks and mechanisms, many quorum quenching methods have been developed against various clinically significant bacterial pathogens. In particular, Gram-negative bacteria are an important group of pathogens, because, collectively, they are responsible for the majority of hospital-acquired infections. Here, we discuss the current understanding of existing quorum sensing mechanisms and present important inhibitory strategies that have been developed against this group of pathogenic bacteria.

  15. Titanium dioxide nanoparticles enhance mortality of fish exposed to bacterial pathogens

    International Nuclear Information System (INIS)

    Jovanović, Boris; Whitley, Elizabeth M.; Kimura, Kayoko; Crumpton, Adam; Palić, Dušan

    2015-01-01

    Nano-TiO 2 is immunotoxic to fish and reduces the bactericidal function of fish neutrophils. Here, fathead minnows (Pimephales promelas) were exposed to low and high environmentally relevant concentration of nano-TiO 2 (2 ng g −1 and 10 μg g −1 body weight, respectively), and were challenged with common fish bacterial pathogens, Aeromonas hydrophila or Edwardsiella ictaluri. Pre-exposure to nano-TiO 2 significantly increased fish mortality during bacterial challenge. Nano-TiO 2 concentrated in the kidney and spleen. Phagocytosis assay demonstrated that nano-TiO 2 has the ability to diminish neutrophil phagocytosis of A. hydrophila. Fish injected with TiO 2 nanoparticles displayed significant histopathology when compared to control fish. The interplay between nanoparticle exposure, immune system, histopathology, and infectious disease pathogenesis in any animal model has not been described before. By modulating fish immune responses and interfering with resistance to bacterial pathogens, manufactured nano-TiO 2 has the potential to affect fish survival in a disease outbreak. - Highlights: • First data on the effect of nano-TiO 2 pre-exposure on responses to bacterial pathogens. • Interplay between nano-TiO 2 , immune system, histopathology, and bacteria is described. • Nano-TiO 2 has the potential to affect fish population survival in a disease outbreak. - By modulating fish immune responses and interfering with resistance to bacterial pathogens, internalized environmentally relevant concentrations of nano-TiO 2 have potential to increase mortality of fish exposed to infectious disease challenge

  16. Solanum lycopersicum (tomato) hosts robust phyllosphere and rhizosphere bacterial communities when grown in soil amended with various organic and synthetic fertilizers.

    Science.gov (United States)

    Allard, Sarah M; Walsh, Christopher S; Wallis, Anna E; Ottesen, Andrea R; Brown, Eric W; Micallef, Shirley A

    2016-12-15

    Due to the intimate association between plants and their microbial symbionts, an examination of the influence of agricultural practices on phytobiome structure and diversity could foster a more comprehensive understanding of plant health and produce safety. Indeed, the impact of upstream crop producti006Fn practices cannot be overstated in their role in assuring an abundant and safe food supply. To assess whether fertilizer type impacted rhizosphere and phyllosphere bacterial communities associating with tomato plants, the bacterial microbiome of tomato cv. 'BHN602' grown in soils amended with fresh poultry litter, commercially available sterilized poultry litter pellets, vermicompost or synthetic fertilizer was described. Culture independent DNA was extracted from bulk and rhizosphere soils, and washes of tomato blossoms and ripe fruit. PCR amplicons of hypervariable regions of the 16S rRNA gene were sequenced and profiled using the QIIME pipeline. Bulk and rhizosphere soil, and blossom and fruit surfaces all supported distinct bacterial communities according to principal coordinate analysis and ANOSIM (R=0.87, p=0.001 in year 1; R=0.93, p=0.001 in year 2). Use of microbiologically diverse organic fertilizers generally did not influence bacterial diversity, community structure or relative abundance of specific taxa on any plant organ surface. However, statistically significant differences in sand and silt contents of soil (pwater activity were positively (R 2 =0.52, p=0.005) and negatively (R 2 =0.48, p=0.009) correlated with changes in bacterial community structure in the rhizosphere, respectively. Over two harvest seasons, this study demonstrated that the application of raw poultry manure, poultry litter pellets and vermicompost had little effect on the tomato microbiome in the rhizosphere and phyllosphere, when compared to synthetically fertilized plants. Plant anatomy, and other factors related to field location, possibly associated with edaphic and air

  17. Detection of multi-tomato leaf diseases (late blight, target and bacterial spots) in different stages by using a spectral-based sensor.

    Science.gov (United States)

    Lu, Jinzhu; Ehsani, Reza; Shi, Yeyin; de Castro, Ana Isabel; Wang, Shuang

    2018-02-12

    Several diseases have threatened tomato production in Florida, resulting in large losses, especially in fresh markets. In this study, a high-resolution portable spectral sensor was used to investigate the feasibility of detecting multi-diseased tomato leaves in different stages, including early or asymptomatic stages. One healthy leaf and three diseased tomato leaves (late blight, target and bacterial spots) were defined into four stages (healthy, asymptomatic, early stage and late stage) and collected from a field. Fifty-seven spectral vegetation indices (SVIs) were calculated in accordance with methods published in previous studies and established in this study. Principal component analysis was conducted to evaluate SVIs. Results revealed six principal components (PCs) whose eigenvalues were greater than 1. SVIs with weight coefficients ranking from 1 to 30 in each selected PC were applied to a K-nearest neighbour for classification. Amongst the examined leaves, the healthy ones had the highest accuracy (100%) and the lowest error rate (0) because of their uniform tissues. Late stage leaves could be distinguished more easily than the two other disease categories caused by similar symptoms on the multi-diseased leaves. Further work may incorporate the proposed technique into an image system that can be operated to monitor multi-diseased tomato plants in fields.

  18. Host-directed antimicrobial drugs with broad-spectrum efficacy against intracellular bacterial pathogens.

    Science.gov (United States)

    Czyż, Daniel M; Potluri, Lakshmi-Prasad; Jain-Gupta, Neeta; Riley, Sean P; Martinez, Juan J; Steck, Theodore L; Crosson, Sean; Shuman, Howard A; Gabay, Joëlle E

    2014-07-29

    We sought a new approach to treating infections by intracellular bacteria, namely, by altering host cell functions that support their growth. We screened a library of 640 Food and Drug Administration (FDA)-approved compounds for agents that render THP-1 cells resistant to infection by four intracellular pathogens. We identified numerous drugs that are not antibiotics but were highly effective in inhibiting intracellular bacterial growth with limited toxicity to host cells. These compounds are likely to target three kinds of host functions: (i) G protein-coupled receptors, (ii) intracellular calcium signals, and (iii) membrane cholesterol distribution. The compounds that targeted G protein receptor signaling and calcium fluxes broadly inhibited Coxiella burnetii, Legionella pneumophila, Brucella abortus, and Rickettsia conorii, while those directed against cholesterol traffic strongly attenuated the intracellular growth of C. burnetii and L. pneumophila. These pathways probably support intracellular pathogen growth so that drugs that perturb them may be therapeutic candidates. Combining host- and pathogen-directed treatments is a strategy to decrease the emergence of drug-resistant intracellular bacterial pathogens. Importance: Although antibiotic treatment is often successful, it is becoming clear that alternatives to conventional pathogen-directed therapy must be developed in the face of increasing antibiotic resistance. Moreover, the costs and timing associated with the development of novel antimicrobials make repurposed FDA-approved drugs attractive host-targeted therapeutics. This paper describes a novel approach of identifying such host-targeted therapeutics against intracellular bacterial pathogens. We identified several FDA-approved drugs that inhibit the growth of intracellular bacteria, thereby implicating host intracellular pathways presumably utilized by bacteria during infection. Copyright © 2014 Czyż et al.

  19. Clinical characteristics, pathogens implicated and therapeutic outcomes of mixed infection in adult bacterial meningitis

    Directory of Open Access Journals (Sweden)

    Wan-Chen Tsai

    2012-10-01

    Full Text Available We reviewed retrospectively the data for adult patients with bacterial meningitis over a period of 10.5 years in our hospital. The clinical characteristics and laboratory data of the 21 cases (52 strains of mixed infection were analyzed. Two hundred and fifteen cases of single pathogen adult bacterial meningitis (ABM were also included for comparison. Post-neurosurgical type of ABM was presented in 86% of the mixed infection group. Brain abscess was found in three patients. Fourteen patients survived and seven cases died. The analysis showed a statistical significance for the mixed infection group having a higher rate of nosocomially-acquired, post-neurosurgical condition, hydrocephalus, and lower level of cerebrospinal fluid white cell count, protein and lactate than the single pathogen group. Logistic regression analysis showed the independent factor of “hydrocephalus” (p = 0.002. Presence of hydrocephalus is a significant neuroimaging feature when compared with the single pathogen group. As compared with the previous study results of mixed infection in ABM, the present study showed a change of pathogens implicated of increasing Pseudomonas spp. and Acinetobacter spp. infections, and an emergence of anaerobic pathogens. All these changes deserve special attention because of the need for an appropriate choice of empirical antibiotics and choice of culture method.

  20. Genetically Engineered Broad-Spectrum Disease Resistance in Tomato

    Science.gov (United States)

    Oldroyd, Giles E. D.; Staskawicz, Brian J.

    1998-08-01

    Resistance in tomato to the bacterial pathogen Pseudomonas syringae pathovar tomato requires Pto and Prf. Mutations that eliminate Prf show a loss of both Pto resistance and sensitivity to the organophosphate insecticide fenthion, suggesting that Prf controls both phenotypes. Herein, we report that the overexpression of Prf leads to enhanced resistance to a number of normally virulent bacterial and viral pathogens and leads to increased sensitivity to fenthion. These plants express levels of salicylic acid comparable to plants induced for systemic acquired resistance (SAR) and constitutively express pathogenesis related genes. These results suggest that the overexpression of Prf activates the Pto and Fen pathways in a pathogen-independent manner and leads to the activation of SAR. Transgene-induced SAR has implications for the generation of broad spectrum disease resistance in agricultural crop plants.

  1. Resistance to fungal pathogens triggered by the Cf9-Avr9 response in tomato and oilseed rape in the absence of hypersensitive cell death.

    Science.gov (United States)

    Hennin, Caroline; Diederichsen, Elke; Höfte, Monica

    2002-01-01

    summary In tomato and related species, the Cf9 resistance gene induces hypersensitive cell death and activates downstream defence pathways upon recognition of the Avr9 elicitor. We investigated whether the Cf9-Avr9 response without hypersensitive cell death symptoms increases resistance to several fungi. A low Avr9 dose that does not cause hypersensitive cell death was injected in Cf9 tomato and transgenic Cf9 oilseed rape plants. Subsequently, the injected leaves were infected with different fungal pathogens. The disease development of Botrytis cinerea was delayed in Cf9 tomato when the pathogen was inoculated on, or around, the Avr9 injection site. Disease development of Leptosphaeria maculans and Sclerotinia sclerotiorum was delayed on Cf9 oilseed rape plant parts located around the Avr9 injection site. Disease development of Oidium lycopersicum in Cf9 tomato or Erysiphe polygoni in Cf9 oilseed rape was not restricted on leaves injected with Avr9. The Avr9 injection induced systemic resistance to L. maculans and E. polygoni in Cf9 oilseed rape. F(1)(Cf9xAvr9) oilseed rape plants, obtained from crosses of transgenic Cf9x transgenic Avr9 oilseed rape, exhibited higher levels of resistance to L. maculans and E. polygoni but not to S. sclerotiorum, than wild-type plants. F(1)(Cf9xAvr9) plants treated with benzothiadiazole (BTH) did not show elevated levels of expression of some pathogenesis-related genes but developed higher levels of resistance to L. maculans than BTH-treated wild-type plants. This report demonstrates that the hypersensitive cell death which is associated with the Cf9-Avr9 response is not required for quantitative disease resistance.

  2. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Science.gov (United States)

    Furuse, Yuki; Finethy, Ryan; Saka, Hector A; Xet-Mull, Ana M; Sisk, Dana M; Smith, Kristen L Jurcic; Lee, Sunhee; Coers, Jörn; Valdivia, Raphael H; Tobin, David M; Cullen, Bryan R

    2014-01-01

    MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼ 23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin.

  3. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Directory of Open Access Journals (Sweden)

    Yuki Furuse

    Full Text Available MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼ 23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin.

  4. Antibacterial screening of traditional herbal plants and standard antibiotics against some human bacterial pathogens.

    Science.gov (United States)

    Awan, Uzma Azeem; Andleeb, Saiqa; Kiyani, Ayesha; Zafar, Atiya; Shafique, Irsa; Riaz, Nazia; Azhar, Muhammad Tehseen; Uddin, Hafeez

    2013-11-01

    Chloroformic and isoamyl alcohol extracts of Cinnnamomum zylanicum, Cuminum cyminum, Curcuma long Linn, Trachyspermum ammi and selected standard antibiotics were investigated for their in vitro antibacterial activity against six human bacterial pathogens. The antibacterial activity was evaluated and based on the zone of inhibition using agar disc diffusion method. The tested bacterial strains were Streptococcus pyogenes, Staphylococcus epidermidis, Klebsiella pneumonia, Staphylococcus aurues, Serratia marcesnces, and Pseudomonas aeruginosa. Ciprofloxacin showed highly significant action against K. pneumonia and S. epidermidis while Ampicillin and Amoxicillin indicated lowest antibacterial activity against tested pathogens. Among the plants chloroform and isoamyl alcohol extracts of C. cyminum, S. aromaticum and C. long Linn had significant effect against P. aeruginosa, S. marcesnces and S. pyogenes. Comparison of antibacterial activity of medicinal herbs and standard antibiotics was also recorded via activity index. Used medicinal plants have various phytochemicals which reasonably justify their use as antibacterial agent.

  5. Phage-based biomolecular filter for the capture of bacterial pathogens in liquid streams

    Science.gov (United States)

    Du, Songtao; Chen, I.-Hsuan; Horikawa, Shin; Lu, Xu; Liu, Yuzhe; Wikle, Howard C.; Suh, Sang Jin; Chin, Bryan A.

    2017-05-01

    This paper investigates a phage-based biomolecular filter that enables the evaluation of large volumes of liquids for the presence of small quantities of bacterial pathogens. The filter is a planar arrangement of phage-coated, strip-shaped magnetoelastic (ME) biosensors (4 mm × 0.8 mm × 0.03 mm), magnetically coupled to a filter frame structure, through which a liquid of interest flows. This "phage filter" is designed to capture specific bacterial pathogens and allow non-specific debris to pass, eliminating the common clogging issue in conventional bead filters. ANSYS Maxwell was used to simulate the magnetic field pattern required to hold ME biosensors densely and to optimize the frame design. Based on the simulation results, a phage filter structure was constructed, and a proof-in-concept experiment was conducted where a Salmonella solution of known concentration were passed through the filter, and the number of captured Salmonella was quantified by plate counting.

  6. A Genoproteomic Approach to Detect Peptide Markers of Bacterial Respiratory Pathogens.

    Science.gov (United States)

    Wang, Honghui; Drake, Steven K; Yong, Chen; Gucek, Marjan; Lyes, Matthew A; Rosenberg, Avi Z; Soderblom, Erik; Arthur Moseley, M; Dekker, John P; Suffredini, Anthony F

    2017-08-01

    Rapid identification of respiratory pathogens may facilitate targeted antimicrobial therapy. Direct identification of bacteria in bronchoalveolar lavage (BAL) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is confounded by interfering substances. We describe a method to identify unique peptide markers of 5 gram-negative bacteria by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for direct pathogen identification in BAL. In silico translation and digestion were performed on 14-25 whole genomes representing strains of Acinetobacter baumannii , Moraxella catarrhalis , Pseudomonas aeruginosa , Stenotrophomonas maltophilia , and Klebsiella pneumoniae . Peptides constituting theoretical core peptidomes in each were identified. Rapid tryptic digestion was performed; peptides were analyzed by LC-MS/MS and compared with the theoretical core peptidomes. High-confidence core peptides (false discovery rate identified and analyzed with the lowest common ancestor search to yield potential species-specific peptide markers. The species specificity of each peptide was verified with protein BLAST. Further, 1 or 2 pathogens were serially diluted into pooled inflamed BAL, and a targeted LC-MS/MS assay was used to detect 25 peptides simultaneously. Five unique peptides with the highest abundance for each pathogen distinguished these pathogens with varied detection sensitivities. Peptide markers for A. baumannii and P. aeruginosa , when spiked simultaneously into inflamed BAL, were detected with as few as 3.6 (0.2) × 10 3 and 2.2 (0.6) × 10 3 colony-forming units, respectively, by targeted LC-MS/MS. This proof-of-concept study shows the feasibility of identifying unique peptides in BAL for 5 gram-negative bacterial pathogens, and it may provide a novel approach for rapid direct identification of bacterial pathogens in BAL. © 2017 American Association for Clinical Chemistry.

  7. A Novel Bacterial Pathogen of Biomphalaria glabrata: A Potential Weapon for Schistosomiasis Control?

    OpenAIRE

    Duval, David; Galinier, Richard; Mouahid, Gabriel; Toulza, Eve; Allienne, Jean-François,; Portela, Julien; Calvayrac, Christophe; Rognon, Anne; Arancibia, Nathalie; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

    2015-01-01

    International audience; The present paper reports the isolation and the characterization of a new microbial pathogen of the freshwater snail, Biomphalaria glabrata. Genetic analyses revealed that the species has not been previously described and could be classified into the Paenibacillus genus. These bacteria invade most snail tissues and proliferate, causing massive lethality. Moreover, the bacterial infection can be transmitted both vertically and horizontally to other snails, causing their...

  8. The role of phagocytes and specific antibodies in gamma irradiated mice infected by intracellular bacterial pathogens

    International Nuclear Information System (INIS)

    Kovarova, H.; Stulik, J.; Ledvina, M.

    1987-01-01

    The activation of oxygen metabolism in peritoneal macrophages during the defence against Francisella tularensis infection was inhibited by gamma irradiation of mice with 4.0 Gy. The application of specific antibodies protected the irradiated mice from the lethal infection without reactivation of oxygen metabolism in mononuclear phagocytes. These results demonstrated that the protecting function of the specific antibodies in the defence system against intracellular bacterial pathogens will be mediated by the oxygen-independent mechanisms. (author)

  9. Nested PCR Assay for Eight Pathogens: A Rapid Tool for Diagnosis of Bacterial Meningitis.

    Science.gov (United States)

    Bhagchandani, Sharda P; Kubade, Sushant; Nikhare, Priyanka P; Manke, Sonali; Chandak, Nitin H; Kabra, Dinesh; Baheti, Neeraj N; Agrawal, Vijay S; Sarda, Pankaj; Mahajan, Parikshit; Ganjre, Ashish; Purohit, Hemant J; Singh, Lokendra; Taori, Girdhar M; Daginawala, Hatim F; Kashyap, Rajpal S

    2016-02-01

    Bacterial meningitis is a dreadful infectious disease with a high mortality and morbidity if remained undiagnosed. Traditional diagnostic methods for bacterial meningitis pose a challenge in accurate identification of pathogen, making prognosis difficult. The present study is therefore aimed to design and evaluate a specific and sensitive nested 16S rDNA genus-based polymerase chain reaction (PCR) assay using clinical cerebrospinal fluid (CSF) for rapid diagnosis of eight pathogens causing the disease. The present work was dedicated to development of an in-house genus specific 16S rDNA nested PCR covering pathogens of eight genera responsible for causing bacterial meningitis using newly designed as well as literature based primers for respective genus. A total 150 suspected meningitis CSF obtained from the patients admitted to Central India Institute of Medical Sciences (CIIMS), India during the period from August 2011 to May 2014, were used to evaluate clinical sensitivity and clinical specificity of optimized PCR assays. The analytical sensitivity and specificity of our newly designed genus-specific 16S rDNA PCR were found to be ≥92%. With such a high sensitivity and specificity, our in-house nested PCR was able to give 100% sensitivity in clinically confirmed positive cases and 100% specificity in clinically confirmed negative cases indicating its applicability in clinical diagnosis. Our in-house nested PCR system therefore can diagnose the accurate pathogen causing bacterial meningitis and therefore be useful in selecting a specific treatment line to minimize morbidity. Results are obtained within 24 h and high sensitivity makes this nested PCR assay a rapid and accurate diagnostic tool compared to traditional culture-based methods.

  10. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F; Velvis, H; Zachow, C; Berg, G; Van Elsas, JD; Sessitsch, A

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4

  11. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F.; Velvis, H.; Zachow, C.; Berg, G.; Elsas, van J.D.; Sessitsch, A.

    2006-01-01

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4

  12. Intestinal bacterial overgrowth includes potential pathogens in the carbohydrate overload models of equine acute laminitis.

    Science.gov (United States)

    Onishi, Janet C; Park, Joong-Wook; Prado, Julio; Eades, Susan C; Mirza, Mustajab H; Fugaro, Michael N; Häggblom, Max M; Reinemeyer, Craig R

    2012-10-12

    Carbohydrate overload models of equine acute laminitis are used to study the development of lameness. It is hypothesized that a diet-induced shift in cecal bacterial communities contributes to the development of the pro-inflammatory state that progresses to laminar failure. It is proposed that vasoactive amines, protease activators and endotoxin, all bacterial derived bioactive metabolites, play a role in disease development. Questions regarding the oral bioavailability of many of the bacterial derived bioactive metabolites remain. This study evaluates the possibility that a carbohydrate-induced overgrowth of potentially pathogenic cecal bacteria occurs and that bacterial translocation contributes toward the development of the pro-inflammatory state. Two groups of mixed-breed horses were used, those with laminitis induced by cornstarch (n=6) or oligofructan (n=6) and non-laminitic controls (n=8). Cecal fluid and tissue homogenates of extra-intestinal sites including the laminae were used to enumerate Gram-negative and -positive bacteria. Horses that developed Obel grade2 lameness, revealed a significant overgrowth of potentially pathogenic Gram-positive and Gram-negative intestinal bacteria within the cecal fluid. Although colonization of extra-intestinal sites with potentially pathogenic bacteria was not detected, results of this study indicate that cecal/colonic lymphadenopathy and eosinophilia develop in horses progressing to lameness. It is hypothesized that the pro-inflammatory state in carbohydrate overload models of equine acute laminitis is driven by an immune response to the rapid overgrowth of Gram-positive and Gram-negative cecal bacterial communities in the gut. Further equine research is indicated to study the immunological response, involving the lymphatic system that develops in the model. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Convergent use of RhoGAP toxins by eukaryotic parasites and bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Dominique Colinet

    2007-12-01

    Full Text Available Inactivation of host Rho GTPases is a widespread strategy employed by bacterial pathogens to manipulate mammalian cellular functions and avoid immune defenses. Some bacterial toxins mimic eukaryotic Rho GTPase-activating proteins (GAPs to inactivate mammalian GTPases, probably as a result of evolutionary convergence. An intriguing question remains whether eukaryotic pathogens or parasites may use endogenous GAPs as immune-suppressive toxins to target the same key genes as bacterial pathogens. Interestingly, a RhoGAP domain-containing protein, LbGAP, was recently characterized from the parasitoid wasp Leptopilina boulardi, and shown to protect parasitoid eggs from the immune response of Drosophila host larvae. We demonstrate here that LbGAP has structural characteristics of eukaryotic RhoGAPs but that it acts similarly to bacterial RhoGAP toxins in mammals. First, we show by immunocytochemistry that LbGAP enters Drosophila immune cells, plasmatocytes and lamellocytes, and that morphological changes in lamellocytes are correlated with the quantity of LbGAP they contain. Demonstration that LbGAP displays a GAP activity and specifically interacts with the active, GTP-bound form of the two Drosophila Rho GTPases Rac1 and Rac2, both required for successful encapsulation of Leptopilina eggs, was then achieved using biochemical tests, yeast two-hybrid analysis, and GST pull-down assays. In addition, we show that the overall structure of LbGAP is similar to that of eukaryotic RhoGAP domains, and we identify distinct residues involved in its interaction with Rac GTPases. Altogether, these results show that eukaryotic parasites can use endogenous RhoGAPs as virulence factors and that despite their differences in sequence and structure, eukaryotic and bacterial RhoGAP toxins are similarly used to target the same immune pathways in insects and mammals.

  14. General and specialized media routinely employed for primary isolation of bacterial pathogens of fishes

    Science.gov (United States)

    Starliper, C.E.

    2008-01-01

    There are a number of significant diseases among cultured and free-ranging freshwater fishes that have a bacterial etiology; these represent a variety of gram-negative and gram-positive genera. Confirmatory diagnosis of these diseases involves primary isolation of the causative bacterium on bacteriologic media. Frequently used "general" bacteriologic media simply provide the essential nutrients for growth. For most of the major pathogens, however, there are differential and/or selective media that facilitate primary recovery. Some specialized media are available as "ready-to-use" from suppliers, while others must be prepared. Differential media employ various types of indicator systems, such as pH indicators, that allow diagnosticians to observe assimilation of selected substrates. An advantage to the use of differential media for primary isolation is that they hasten bacterial characterization by yielding the appropriate positive or negative result for a particular substrate, often leading to a presumptive identification. Selective media also incorporate agent(s) that inhibit the growth of contaminants typically encountered with samples from aquatic environments. Media that incorporate differential and/or selective components are ideally based on characters that are unique to the targeted bacterium, and their use can reduce the time associated with diagnosis and facilitate early intervention in affected fish populations. In this review, the concepts of general and differential/selective bacteriologic media and their use and development for fish pathogens are discussed. The media routinely employed for primary isolation of the significant bacterial pathogens of fishes are presented. ?? Wildlife Disease Association 2008.

  15. EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), 2014. Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 2 (Salmonella and Norovirus in tomatoes)

    DEFF Research Database (Denmark)

    Hald, Tine; Baggesen, Dorte Lau

    consumption between 2007 and 2012. Risk factors for tomato contamination by Salmonella and Norovirus were considered in the context of the whole food chain. Available estimates of the Salmonella and Norovirus occurrence in tomatoes were evaluated together with mitigation options relating to prevention...... of contamination and the relevance of microbiological criteria. It was concluded that each farm environment represents a unique combination of risk factors that can influence occurrence and persistence of pathogens in tomato production. Appropriate implementation of food safety management systems including Good...... to provide a risk base for establishing a Norovirus Food Safety Criterion for these foods....

  16. Microplastics as a vector for the transport of the bacterial fish pathogen species Aeromonas salmonicida.

    Science.gov (United States)

    Viršek, Manca Kovač; Lovšin, Marija Nika; Koren, Špela; Kržan, Andrej; Peterlin, Monika

    2017-12-15

    Microplastics is widespread in the marine environment where it can cause numerous negative effects. It can provide space for the growth of organisms and serves as a vector for the long distance transfer of marine microorganisms. In this study, we examined the sea surface concentrations of microplastics in the North Adriatic and characterized bacterial communities living on the microplastics. DNA from microplastics particles was isolated by three different methods, followed by PCR amplification of 16S rDNA, clone libraries preparation and phylogenetic analysis. 28 bacterial species were identified on the microplastics particles including Aeromonas spp. and hydrocarbon-degrading bacterial species. Based on the 16S rDNA sequences the pathogenic fish bacteria Aeromonas salmonicida was identified for the first time on microplastics. Because A. salmonicida is responsible for illnesses in fish, it is crucial to get answers if and how microplastics pollution is responsible for spreading of diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. A retrospective analysis of antimicrobial resistance in bacterial pathogens in an equine hospital (2012-2015).

    Science.gov (United States)

    van Spijk, J N; Schmitt, S; Fürst, A E; Schoster, A

    2016-06-01

    Antimicrobial resistance has become an important concern in veterinary medicine. The aim of this study was to describe the rate of antimicrobial resistance in common equine pathogens and to determine the occurrence of multidrug-resistant isolates. A retrospective analysis of all susceptibility testing results from bacterial pathogens cultured from horses at the University of Zurich Equine Hospital (2012-2015) was performed. Strains exhibiting resistance to 3 or more antimicrobial categories were defined as multidrug-resistant. Susceptibility results from 303 bacterial pathogens were analyzed, most commonly Escherichia coli (60/303, 20%) and Staphylococcus aureus (40/303, 13%). High rates of acquired resistance against commonly used antimicrobials were found in most of the frequently isolated equine pathogens. The highest rate of multidrug resistance was found in isolates of Acinetobacter baumannii (23/24, 96%), followed by Enterobacter cloacae complex (24/28, 86%) and Escherichia coli (48/60, 80%). Overall, 60% of Escherichia coli isolates were phenotypically ESBL-producing and 68% of Staphylococcus spp. were phenotypically methicillin-resistant. High rates of acquired antimicrobial resistance towards commonly used antibiotics are concerning and underline the importance of individual bacteriological and antimicrobial susceptibility testing to guide antimicrobial therapy. Minimizing and optimizing antimicrobial therapy in horses is needed.

  18. Analysis of bacterial metagenomes from the Southwestern Gulf of Mexico for pathogens detection.

    Science.gov (United States)

    Escobedo-Hinojosa, Wendy; Pardo-López, Liliana

    2017-07-31

    Little is known about the diversity of bacteria in the Southwestern Gulf of Mexico. The aim of the study illustrated in this perspective was to search for the presence of bacterial pathogens in this ecosystem, using metagenomic data recently generated by the Mexican research group known as the Gulf of Mexico Research Consortium. Several genera of bacteria annotated as pathogens were detected in water and sediment marine samples. As expected, native and ubiquitous pathogenic bacteria genera such as Burkolderia, Halomonas, Pseudomonas, Shewanella and Vibrio were highly represented. Surprisingly, non-native genera of public health concern were also detected, including Borrelia, Ehrlichia, Leptospira, Mycobacterium, Mycoplasma, Salmonella, Staphylococcus, Streptococcus and Treponema. While there are no previous metagenomics studies of this environment, the potential influences of natural, anthropogenic and ecological factors on the diversity of putative pathogenic bacteria found in it are reviewed. The taxonomic annotation herein reported provides a starting point for an improved understanding of bacterial biodiversity in the Southwestern Gulf of Mexico. It also represents a useful tool in public health as it may help identify infectious diseases associated with exposure to marine water and ingestion of fish or shellfish, and thus may be useful in predicting and preventing waterborne disease outbreaks. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Bacterial and viral pathogens detected in sea turtles stranded along the coast of Tuscany, Italy.

    Science.gov (United States)

    Fichi, G; Cardeti, G; Cersini, A; Mancusi, C; Guarducci, M; Di Guardo, G; Terracciano, G

    2016-03-15

    During 2014, six loggerhead turtles, Caretta caretta and one green turtle, Chelonia mydas, found stranded on the Tuscany coast of Italy, were examined for the presence of specific bacterial and viral agents, along with their role as carriers of fish and human pathogens. Thirteen different species of bacteria, 10 Gram negative and 3 Gram positive, were identified. Among them, two strains of Vibrio parahaemolyticus and one strain of Lactococcus garviae were recovered and confirmed by specific PCR protocols. No trh and tdh genes were detected in V. parahaemolyticus. The first isolation of L. garviae and the first detection of Betanodavirus in sea turtles indicate the possibility for sea turtles to act as carriers of fish pathogens. Furthermore, the isolation of two strains of V. parahaemolyticus highlights the possible role of these animals in human pathogens' diffusion. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Evaluation of tomato rootstocks and its use to control bacterial wilt diseaseAvaliação de porta-enxertos de tomateiro e o uso da enxertia no controle da murcha bacteriana

    Directory of Open Access Journals (Sweden)

    Francisco Ferraz Laranjeira

    2012-05-01

    Full Text Available Tomato plants are susceptible to bacterial wilting, which causes production losses varying from 10 to 100 %. A method for controlling this disease is the use of grafting on resistant rootstocks. This work had the objective of evaluating tomato genotypes for the resistance to Ralstonia solanacearum and the grafting technique as an alternative for the bacterial wilt control in the region of Recôncavo Baiano, Brazil. To evaluate the resistance to R. solanacearum, four local genotypes, collected in different regions of Bahia, the cv. Santa Clara as a susceptible treatment, and the Hawaii 7996 (H7996, as a resistant treatment were studied. For the evaluation of grafting method for control of bacterial wilt, the H7996 was used as rootstock, and the cvs. Santa Clara, Santa Cruz Kada, and Débora Plus were used as the scion plants. Both experiments were evaluated in an area infested with R. solanacearum, for a period of 65 days for the selection of the rootstocks and 45 days for the evaluation of the grafting method. Only the H7996 can be recommended as a R. solanacearum resistant rootstock. The other genotypes showed susceptibility to the pathogen. The grafting on the H7996 did not show incompatibility with the scion tomato cultivars tested and reached 100 % control of the bacterial wilt disease, for all treatments, suggesting that this method can be used as an alternative for the bacterial wilt control, allowing the production of susceptible tomato cultivars in areas infested with R. solanacearum A suscetibilidade do tomateiro à murcha bacteriana (Ralstonia solanacearum causa perdas que vão de 10 a 100 % na produção e uma das alternativas de controle que vem sendo utilizada é a enxertia com porta-enxerto resistente. Este trabalho teve o objetivo avaliar genótipos de tomateiro quanto à resistência a R. solanacearum e a enxertia como alternativa para o controle da murcha bacteriana do tomateiro na região do Recôncavo Baiano. Para avalia

  1. Occurrence and antibacterial susceptibility pattern of bacterial pathogens isolated from diarrheal patients in Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad H. Rasool

    2016-03-01

    Full Text Available Objective: To determine the occurrence of bacterial pathogens responsible for diarrhea and to engender information regarding the effectiveness of commonly used antibiotic against diarrhea. Methods: This cross-sectional study was conducted between April and July 2014. Samples were collected from the Divisional Headquarter and Allied Hospital, Faisalabad, Pakistan. The differential and selective media were used to isolate bacterial pathogens, which were identified through cultural characteristics, microscopy, and biochemical tests. Disc diffusion assay was carried out using Muller Hinton agar medium, and minimum inhibitory concentration was determined using broth dilution method against isolated pathogens. Results: One hundred and forty-one (100% samples were positive for some bacteria. Frequency of occurrence was Bacillus cereus (B. cereus (66%, Escherichia coli (E. coli (48.5%, Salmonella typhi (S. Typhi (27.7%, Pseudomonas aeruginosa (P. aeruginosa (8.5%, and Staphylococcus aureus (S. aureus (4.3%. Single pathogen was detected in 20 (14.2% samples whereas combinations were found in 121 (85.8% samples. Bacillus cereus and E. coli were the most frequently detected pathogens followed by the S. Typhi, P. aeruginosa, and Staph. aureus. The percentage occurrence of isolated pathogens was 31% in B. cereus, 31% in E. coli, 18% in S. Typhi, 5% in P. aeruginosa, and 3% in Staph. aureus. Conclusion: Pseudomonas aeruginosa showed resistance against Amoxicillin and Cefotaxime, whereas S. aureus was found resistant against Cefotaxime. Statistical analysis using one way Analysis of Variance revealed that Ofloxacin and Gentamicin had significant (p<0.05 differences against all isolates as compared with other antibiotics used in this study.

  2. [Pathogen distribution and bacterial resistance in children with severe community-acquired pneumonia].

    Science.gov (United States)

    Lu, Yun-Yun; Luo, Rong; Fu, Zhou

    2017-09-01

    To investigate the distribution of pathogens and bacterial resistance in children with severe community-acquired pneumonia (CAP). A total of 522 children with severe CAP who were hospitalized in 2016 were enrolled as study subjects. According to their age, they were divided into infant group (402 infants aged 28 days to 1 year), young children group (73 children aged 1 to 3 years), preschool children group (35 children aged 3 to 6 years), and school-aged children group (12 children aged ≥6 years). According to the onset season, all children were divided into spring group (March to May, 120 children), summer group (June to August, 93 children), autumn group (September to November, 105 children), and winter group (December to February, 204 children). Sputum specimens from the deep airway were collected from all patients. The phoenix-100 automatic bacterial identification system was used for bacterial identification and drug sensitivity test. The direct immunofluorescence assay was used to detect seven common respiratory viruses. The quantitative real-time PCR was used to detect Mycoplasma pneumoniae (MP) and Chlamydia trachomatis (CT). Of all the 522 children with severe CAP, 419 (80.3%) were found to have pathogens, among whom 190 (45.3%) had mixed infection. A total of 681 strains of pathogens were identified, including 371 bacterial strains (54.5%), 259 viral strains (38.0%), 12 fungal strains (1.8%), 15 MP strains (2.2%), and 24 CT strains (3.5%). There were significant differences in the distribution of bacterial, viral, MP, and fungal infections between different age groups (Presistance rates of Streptococcus pneumoniae to erythromycin, tetracycline, and clindamycin reached above 85%, and the drug-resistance rates of Staphylococcus aureus to penicillin, erythromycin, and clindamycin were above 50%; they were all sensitive to vancomycin and linezolid. The drug-resistance rates of Haemophilus influenzae to cefaclor and cefuroxime were above 60%, but it was

  3. Studies on the O-specific polysaccharide of the lipopolysaccharide from the Pseudomonas mediterranea strain C5P1rad1, a bacterium pathogenic of tomato and chrysanthemum.

    Science.gov (United States)

    Zdorovenko, Evelina L; Cimmino, Alessio; Marchi, Guido; Shashkov, Alexander S; Fiori, Mario; Knirel, Yuriy A; Evidente, Antonio

    2017-08-07

    An O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Pseudomonas mediterranea strain C5P1rad1, the causal agents of tomato pith necrosis and Chrysanthemum stem rot, and studied by one- and two-dimensional 1 H and 13 C NMR spectroscopy. The following structure of the trisaccharide repeating unit of the OPS was established, which, to our knowledge, is unique among the known bacterial polysaccharide structures: →4)-β-d-ManpNAc3NAcA-(1 → 4)-β-d-ManpNAc3NAcA-(1 → 3)-α-d-QuipNAc4NAc-(1→ where QuiNAc4NAc and ManNAc3NAcA indicate 2,4-diacetamido-2,4,6-trideoxyglucose and 2,3-diacetamido-2,3-dideoxymannuronic acid, respectively. Pre-treatment of leaves with LPS or OPS preparations at 250 and 50 μg mL -1 did not inhibit development of a hypersensitivity reaction induced by P. mediterranea C5P1rad1 on tobacco, tomato and chrysanthemum plants. The same preparations at 250 μg mL -1 partially prevented elicitation of the hypersensitivity reaction by Pseudomonas syringae KVPT7RC on chrysanthemum but not tobacco and tomato. Copyright © 2017. Published by Elsevier Ltd.

  4. Microbial population profiles of the microflora associated with pre- and postharvest tomatoes contaminated with Salmonella typhimurium or Salmonella montevideo.

    Science.gov (United States)

    Shi, X; Wu, Z; Namvar, A; Kostrzynska, M; Dunfield, K; Warriner, K

    2009-07-01

    To determine the microflora profiles of pre- and postharvest tomatoes contaminated with Salmonella montevideo or S. typhimurium DT104. Salmonella montevideo or S. typhimurium was inoculated onto the flowers of tomato plants with the microflora of the subsequent fruit examined using a combination of Source Carbon Utilization and 16S rDNA-PCR profiling. From 16S rDNA profiles it was evident that tomatoes derived from Salmonella inoculated plants harboured a different microbial population compared to nontreated controls. The same result was observed for tomatoes inoculated at postharvest and subsequently stored for 14 days at 15 degrees C. From sequencing analysis it was found that tomatoes derived from Salmonella inoculated plants but testing negative for the enteric pathogen, frequently harboured Enterobacter and Bacillus spp. In contrast, both bacterial types were not found associated with tomatoes testing positive for Salmonella. Salmonella introduced onto tomatoes at pre- or postharvest alters the composition of the microbial community. The presence of Enterobacter and Bacillus spp negatively affects the persistence of Salmonella on preharvest tomatoes. Salmonella appears to modify rather than become integrated into the microbial communities associated with tomatoes. Yet, the presence of antagonistic bacteria appears to reduce the persistence of the enteric pathogen.

  5. Mutant lines of currant tomato, valuable germplasm with multiple disease resistance

    International Nuclear Information System (INIS)

    Govorova, G.F.; Khrustaleva, V.V.; Shcherbakov, V.K.

    1987-01-01

    Studies were carried out for two years on eight mutant lines of currant tomato at the Krymsk Experimental Breeding Station of the N.I. Vavilov All-Union Scientific Research Institute of Plant-Growing (VIR). The station is situated in an area of commercial field tomato growing (Krasnodar region). The mutant lines of currant tomato (VIR specimen No. k-4053) were obtained through chronic gamma-irradiation. A disease resistance evaluation of the mutants was carried out for Verticillium wilt (Verticillium albo-atrum Rein. and Berth.), for black bacterial spotting (Xanthomonas vesicatoria Dows.), for tobacco mosaic virus Nicotiana 1 Smith), for streak virus (Nicotiana 1), for the combination TMV with X and Y potato viruses, for cucumber virus (Cucumis 1), and also for top rot. Fifty plants of each mutant line were evaluated and checks were made three times in each season. A comparison of the currant tomato mutants with the standard tomato varieties demonstrates the better resistance shown by the mutant germplasm to the main pathogens. The degree to which some currant tomato mutants were affected by Verticillium was lower than that of the most VerticiIlium-resistant samples of tomato evaluated between 1975 and 1981. The mutants of currant tomato should therefore be of interest as germplasm in breeding tomatoes for improved multiple disease resistance

  6. Hemolysin, Protease, and EPS Producing Pathogenic Aeromonas hydrophila Strain An4 Shows Antibacterial Activity against Marine Bacterial Fish Pathogens

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    Anju Pandey

    2010-01-01

    Full Text Available A pathogenic Aeromonas hydrophila strain An4 was isolated from marine catfish and characterized with reference to its proteolytic and hemolytic activity along with SDS-PAGE profile (sodium dodecyl sulphate-Polyacrylamide gel electrophoresis of ECPs (extracellular proteins showing hemolysin (approximately 50 kDa. Agar well diffusion assay using crude cell extract of the bacterial isolate clearly demonstrated antibacterial activity against indicator pathogenic bacteria, Staphylococcus arlettae strain An1, Acinetobacter sp. strain An2, Vibrio parahaemolyticus strain An3, and Alteromonas aurentia SE3 showing inhibitory zone >10 mm well comparable to common antibiotics. Further GC-MS analysis of crude cell extract revealed several metabolites, namely, phenolics, pyrrolo-pyrazines, pyrrolo-pyridine, and butylated hydroxytoluene (well-known antimicrobials. Characterization of EPS using FTIR indicated presence of several protein-related amine and amide groups along with peaks corresponding to carboxylic and phenyl rings which may be attributed to its virulent and antibacterial properties, respectively. Besides hemolysin, EPS, and protease, Aeromonas hydrophila strain An4 also produced several antibacterial metabolites.

  7. Encyclopedia of bacterial gene circuits whose presence or absence correlate with pathogenicity--a large-scale system analysis of decoded bacterial genomes.

    Science.gov (United States)

    Shestov, Maksim; Ontañón, Santiago; Tozeren, Aydin

    2015-10-13

    Bacterial infections comprise a global health challenge as the incidences of antibiotic resistance increase. Pathogenic potential of bacteria has been shown to be context dependent, varying in response to environment and even within the strains of the same genus. We used the KEGG repository and extensive literature searches to identify among the 2527 bacterial genomes in the literature those implicated as pathogenic to the host, including those which show pathogenicity in a context dependent manner. Using data on the gene contents of these genomes, we identified sets of genes highly abundant in pathogenic but relatively absent in commensal strains and vice versa. In addition, we carried out genome comparison within a genus for the seventeen largest genera in our genome collection. We projected the resultant lists of ortholog genes onto KEGG bacterial pathways to identify clusters and circuits, which can be linked to either pathogenicity or synergy. Gene circuits relatively abundant in nonpathogenic bacteria often mediated biosynthesis of antibiotics. Other synergy-linked circuits reduced drug-induced toxicity. Pathogen-abundant gene circuits included modules in one-carbon folate, two-component system, type-3 secretion system, and peptidoglycan biosynthesis. Antibiotics-resistant bacterial strains possessed genes modulating phagocytosis, vesicle trafficking, cytoskeletal reorganization, and regulation of the inflammatory response. Our study also identified bacterial genera containing a circuit, elements of which were previously linked to Alzheimer's disease. Present study produces for the first time, a signature, in the form of a robust list of gene circuitry whose presence or absence could potentially define the pathogenicity of a microbiome. Extensive literature search substantiated a bulk majority of the commensal and pathogenic circuitry in our predicted list. Scanning microbiome libraries for these circuitry motifs will provide further insights into the complex

  8. Rapid methods for the detection of foodborne bacterial pathogens: principles, applications, advantages and limitations

    Science.gov (United States)

    Law, Jodi Woan-Fei; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan; Lee, Learn-Han

    2015-01-01

    The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR), multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases. PMID:25628612

  9. Rapid Methods for the Detection of Foodborne Bacterial Pathogens: Principles, Applications, Advantages and Limitations

    Directory of Open Access Journals (Sweden)

    Law eJodi Woan-Fei

    2015-01-01

    Full Text Available The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR, multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA, loop-mediated isothermal amplification (LAMP and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases.

  10. Isolation and identification of bacterial pathogen from mastitis milk in Central Java Indonesia

    Science.gov (United States)

    Harjanti, D. W.; Ciptaningtyas, R.; Wahyono, F.; Setiatin, ET

    2018-01-01

    Mastitis is a multi-etiologic disease of the mammary gland characterized mainly by reduction in milk production and milk quality due to intramammary infection by pathogenic bacteria. Nearly 83% of lactating dairy cows in Indonesia are infected with mastitis in various inflammation degrees. This study was conducted to isolate and identify the pathogen in milk collected from mastitis-infected dairy cows. The study was carried out in ten smallholder dairy farms in Central Java Indonesia based on animal examination, California mastitis test, isolation bacterial pathogens, Gram staining, Catalase and Coagulase test, and identification of bacteria species using Vitek. Bacteriological examination of milk samples revealed 15 isolates where Streptococcus was predominant species (73.3%) and the coagulase negative Staphylococcus species was identified at the least bacteria (26.7%). The Streptococcus bacteria found were Streptococcus uberis (2 isolates), Streptococcus sanguinis(6 isolates), Streptococcus dysgalactiaessp dysgalactiae(1 isolate) , Streptococcus mitis (1 isolate) and Streptococcus agalactiae (1 isolate). The Staphylococcus isolates comprising of Staphylococcus simulans (1 isolate) and Staphylococcus chromogens (3 isolates). Contamination of raw milkwith pathogenic bacteria can cause outbreaks of human disease (milk borne disease). Thus, proper milk processing method that couldinhibit the growth or kill these pathogenic bacteria is important to ensure the safety of milk and milk products.

  11. Liquid based formulations of bacteriophages for the management of waterborne bacterial pathogens in water microcosms.

    Science.gov (United States)

    Ahiwale, Sangeeta; Tagunde, Sujata; Khopkar, Sushama; Karni, Mrudula; Gajbhiye, Milind; Kapadnis, Balasaheb

    2013-11-01

    Water resources are contaminated by life-threatening multidrug resistant pathogenic bacteria. Unfortunately, these pathogenic bacteria do not respond to the traditional water purification methods. Therefore, there is a need of environmentally friendly strategies to overcome the problems associated with the antimicrobial resistant bacterial pathogens. In the present study, highly potent lytic phages against multidrug-resistant Salmonella enterica serovar Paratyphi B, Pseudomonas aeruginosa and Klebsiella pneumoniae were isolated from the Pavana river water. They belonged to the Podoviridae and Siphoviridae families. These phages were purified and enriched in the laboratory. Monovalent formulations of phiSPB, BVPaP-3 and KPP phages were prepared in three different liquids viz., phage broth, saline and distilled water. The phages were stable for almost 8-10 months in the phage broth at 4 degrees C. The stability of the phages in saline and distilled water was 5-6 months at 4 degrees C. All of the phages were stable only for 4-6 months in the phage broth at 30 degrees C. The monovalent phage formulation of psiSPB was applied at MOI Salmonella enterica serovar Paratyphi B in various water microcosms. The results indicated that there was almost 80 % reduction in the log phase cells of Salmonella serovar Paratyphi B in 24 h. In stationary phase cells, the reduction was comparatively less within same period. At the same time, there was concomitant increase in the phage population by 80% in all the microcosms indicating that psiSPB phage is highly potent in killing pathogen in water. Results strongly support that the formulation of psiSPB in the phage broth in monovalent form could be used as an effective biological disinfectant for preventing transmission of water-borne bacterial pathogens, including antimicrobial resistant ones.

  12. Short term memory of Caenorhabditis elegans against bacterial pathogens involves CREB transcription factor.

    Science.gov (United States)

    Prithika, Udayakumar; Vikneswari, Ramaraj; Balamurugan, Krishnaswamy

    2017-04-01

    One of the key issues pertaining to the control of memory is to respond to a consistently changing environment or microbial niche present in it. Human cyclic AMP response element binding protein (CREB) transcription factor which plays a crucial role in memory has a homolog in C. elegans, crh-1. crh-1 appears to influence memory processes to certain extent by habituation of the host to a particular environment. The discrimination between the pathogen and a non-pathogen is essential for C. elegans in a microbial niche which determines its survival. Training the nematodes in the presence of a virulent pathogen (S. aureus) and an opportunistic pathogen (P. mirabilis) separately exhibits a different behavioural paradigm. This appears to be dependent on the CREB transcription factor. Here we show that C. elegans homolog crh-1 helps in memory response for a short term against the interacting pathogens. Following conditioning of the nematodes to S. aureus and P. mirabilis, the wild type nematodes exhibited a positive response towards the respective pathogens which diminished slowly after 2h. By contrast, the crh-1 deficient nematodes had a defective memory post conditioning. The molecular data reinforces the importance of crh-1 gene in retaining the memory of nematode. Our results also suggest that involvement of neurotransmitters play a crucial role in modulating the memory of the nematode with the assistance of CREB. Therefore, we elucidate that CREB is responsible for the short term memory response in C. elegans against bacterial pathogens. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Inhibitory Effect of Camptothecin against Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae RS-2.

    Science.gov (United States)

    Dong, Qiaolin; Luo, Ju; Qiu, Wen; Cai, Li; Anjum, Syed Ishtiaq; Li, Bin; Hou, Mingsheng; Xie, Guanlin; Sun, Guochang

    2016-07-27

    Camptothecin (CPT) has anticancer, antiviral, and antifungal properties. However, there is a dearth of information about antibacterial activity of CPT. Therefore, in this study, we investigated the inhibitory effect of CPT on Acidovorax avenae subsp. avenae strain RS-2, the pathogen of rice bacterial brown stripe, by measuring cell growth, DNA damage, cell membrane integrity, the expression of secretion systems, and topoisomerase-related genes, as well as the secretion of effector protein Hcp. Results indicated that CPT solutions at 0.05, 0.25, and 0.50 mg/mL inhibited the growth of strain RS-2 in vitro, while the inhibitory efficiency increased with an increase in CPT concentration, pH, and incubation time. Furthermore, CPT treatment affected bacterial growth and replication by causing membrane damage, which was evidenced by transmission electron microscopic observation and live/dead cell staining. In addition, quantitative real-time PCR analysis indicated that CPT treatment caused differential expression of eight secretion system-related genes and one topoisomerase-related gene, while the up-regulated expression of hcp could be justified by the increased secretion of Hcp based on the ELISA test. Overall, this study indicated that CPT has the potential to control the bacterial brown stripe pathogen of rice.

  14. Inhibitory Effect of Camptothecin against Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae RS-2

    Directory of Open Access Journals (Sweden)

    Qiaolin Dong

    2016-07-01

    Full Text Available Camptothecin (CPT has anticancer, antiviral, and antifungal properties. However, there is a dearth of information about antibacterial activity of CPT. Therefore, in this study, we investigated the inhibitory effect of CPT on Acidovorax avenae subsp. avenae strain RS-2, the pathogen of rice bacterial brown stripe, by measuring cell growth, DNA damage, cell membrane integrity, the expression of secretion systems, and topoisomerase-related genes, as well as the secretion of effector protein Hcp. Results indicated that CPT solutions at 0.05, 0.25, and 0.50 mg/mL inhibited the growth of strain RS-2 in vitro, while the inhibitory efficiency increased with an increase in CPT concentration, pH, and incubation time. Furthermore, CPT treatment affected bacterial growth and replication by causing membrane damage, which was evidenced by transmission electron microscopic observation and live/dead cell staining. In addition, quantitative real-time PCR analysis indicated that CPT treatment caused differential expression of eight secretion system-related genes and one topoisomerase-related gene, while the up-regulated expression of hcp could be justified by the increased secretion of Hcp based on the ELISA test. Overall, this study indicated that CPT has the potential to control the bacterial brown stripe pathogen of rice.

  15. Isolation of Biosurfactant–Producing Bacteria with Antimicrobial Activity against Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Siripun Sarin

    2011-01-01

    Full Text Available The aims of this research were to study biosurfactant producing bacteria isolated from soil and to determine their property and efficiency as biosurfactants in order to inhibit bacterial pathogens. The result showed that there were 8 bacterial isolates out of 136 isolates of the total biosurfactant producing bacteria screened that exhibited the diameter of clear zone more than 1.5 cm. in the oil spreading test. The highest potential of emulsifying activity (%EA24 of 54.4 and the maximum additive concentration, (%MAC of 24.2 was obtained from the fermentation broth of the G7 isolate which the G7 isolate was later identified as Pseudomonas fluorescens. Escherichia coli, Staphylococcus aureus and Psuedomonas aeruginosa were the tested bacterial pathogens that were most sensitive to the acid precipitated biosurfactant obtained from P. fluorescens G7 with the lowest minimum inhibitory concentration (MIC of 41.6 mg/ml and minimum bactericidal concentration (MBC of 41.6 mg/ml compared with the acid precipitated bisurfactants of the other isolates used in the antimicrobial activity test. The type of the separated crude biosurfactant produced by P. fluorescens G7 analyzed later by using the rhamose test, TLC and FT-IR techniques was rhamnolipid.

  16. Comparison of individual and pooled sampling methods for detecting bacterial pathogens of fish

    Science.gov (United States)

    Mumford, Sonia; Patterson, Chris; Evered, J.; Brunson, Ray; Levine, J.; Winton, J.

    2005-01-01

    Examination of finfish populations for viral and bacterial pathogens is an important component of fish disease control programs worldwide. Two methods are commonly used for collecting tissue samples for bacteriological culture, the currently accepted standards for detection of bacterial fish pathogens. The method specified in the Office International des Epizooties Manual of Diagnostic Tests for Aquatic Animals permits combining renal and splenic tissues from as many as 5 fish into pooled samples. The American Fisheries Society (AFS) Blue Book/US Fish and Wildlife Service (USFWS) Inspection Manual specifies the use of a bacteriological loop for collecting samples from the kidney of individual fish. An alternative would be to more fully utilize the pooled samples taken for virology. If implemented, this approach would provide substantial savings in labor and materials. To compare the relative performance of the AFS/USFWS method and this alternative approach, cultures of Yersinia ruckeri were used to establish low-level infections in groups of rainbow trout (Oncorhynchus mykiss) that were sampled by both methods. Yersinia ruckeri was cultured from 22 of 37 groups by at least 1 method. The loop method yielded 18 positive groups, with 1 group positive in the loop samples but negative in the pooled samples. The pooled samples produced 21 positive groups, with 4 groups positive in the pooled samples but negative in the loop samples. There was statistically significant agreement (Spearman coefficient 0.80, P methods to permit detection of low-level bacterial infections of rainbow trout.

  17. The Sit-and-Wait Hypothesis in Bacterial Pathogens: A Theoretical Study of Durability and Virulence

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    Liang Wang

    2017-11-01

    Full Text Available The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald’s (2004 review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/- and durability (+/- phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++, vector-borne pathogens (+-, obligate-intracellular bacteria (--, and free-living bacteria (-+. After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher

  18. Antibacterial synergy between quercetin and polyphenolic acids against bacterial pathogens of fish

    Directory of Open Access Journals (Sweden)

    Vinnakota Gangadhara Naga Vara Prasad

    2014-02-01

    Full Text Available Objective: To evaluate combinations of quercetin with gallic acid, p-anisic acid and cinnamic acid in vitro for synergistic activity against common Gram-negative bacterial pathogens of fish viz., Aeromonas hydrophila, Aeromonas salmonicida and Edwardsiella tarda. Methods: Antibacterial activity of quercetin, gallic acid, p-anisic acid and cinnamic acid was determined against selected bacterial pathogens individually, followed by combination of quercetin with polyphenolic acids using serial microplate dilution method measuring minimum inhibitory concentrations. Fractional inhibitory concentration indices were calculated. Results: Quercetin and other polyphenolic compounds exhibited antibacterial action against the selected fish pathogens with mean minimum inhibitory concentrations ranging from 0.83 to 2.5 mg/mL. It was observed that fractional inhibitory concentration indices for combination of quercetin with gallic acid, p-anisic acid or cinnamic acid against Aeromonas salmonicida were less than 0.5, indicating synergistic interaction. However, the above combinations produced additive antimicrobial activity against Aeromonas hydrophila and Edwardsiella tarda. Conclusions: Positive antibacterial interaction was evident between quercetin and selected polyphenolic acids in vitro.

  19. Directed antigen delivery as a vaccine strategy for an intracellular bacterial pathogen

    Science.gov (United States)

    Bouwer, H. G. Archie; Alberti-Segui, Christine; Montfort, Megan J.; Berkowitz, Nathan D.; Higgins, Darren E.

    2006-03-01

    We have developed a vaccine strategy for generating an attenuated strain of an intracellular bacterial pathogen that, after uptake by professional antigen-presenting cells, does not replicate intracellularly and is readily killed. However, after degradation of the vaccine strain within the phagolysosome, target antigens are released into the cytosol for endogenous processing and presentation for stimulation of CD8+ effector T cells. Applying this strategy to the model intracellular pathogen Listeria monocytogenes, we show that an intracellular replication-deficient vaccine strain is cleared rapidly in normal and immunocompromised animals, yet antigen-specific CD8+ effector T cells are stimulated after immunization. Furthermore, animals immunized with the intracellular replication-deficient vaccine strain are resistant to lethal challenge with a virulent WT strain of L. monocytogenes. These studies suggest a general strategy for developing safe and effective, attenuated intracellular replication-deficient vaccine strains for stimulation of protective immune responses against intracellular bacterial pathogens. CD8+ T cell | replication-deficient | Listeria monocytogenes

  20. Aquaporins contribute to diarrhoea caused by attaching and effacing bacterial pathogens.

    Science.gov (United States)

    Guttman, Julian A; Samji, Fereshte N; Li, Yuling; Deng, Wanyin; Lin, Ann; Finlay, B Brett

    2007-01-01

    Attaching and effacing (A/E) pathogens such as enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) cause serious global health problems. These bacteria colonize the gastrointestinal system, attach to intestinal epithelial cells, efface (collapse) infected cell microvilli and cause overt diarrhoea that may ultimately result in death of the host. Although pathogenically induced diarrhoea is a significant global health issue, the molecular mechanisms that underlie this disease remain largely unknown. A natural murine infection model, employing the A/E pathogen Citrobacter rodentium, has been helpful in studying the diseases in vivo. C. rodentium colonize the colon at high levels, attach to colonocytes, efface microvilli and cause hyperplasia and inflammation in infected mice. As the disease progresses, the mice develop a diarrhoea-like phenotype. Aquaporin (AQP) water channels have been proposed to play a role in the normal dehydration of faecal contents. Here we examine whether C. rodentium infection may alter AQP localization in colonocytes. We demonstrate that during infection, AQP2 and AQP3 are mislocalized from their normal location along cell membranes to the cell cytoplasm. The change in localization of these proteins correlates with the diarrhoea-like phenotype present in infected mice. Mice that recover from the infection at 28-35 days post inoculum regain their normal membrane AQP localization. The altered localization of AQPs is partially dependent on the bacterial type III effector proteins EspF and EspG. We conclude that altered AQP localization may be a contributing factor to diarrhoea during bacterial infection.

  1. Animals devoid of pulmonary system as infection models in the study of lung bacterial pathogens

    Science.gov (United States)

    López Hernández, Yamilé; Yero, Daniel; Pinos-Rodríguez, Juan M.; Gibert, Isidre

    2015-01-01

    Biological disease models can be difficult and costly to develop and use on a routine basis. Particularly, in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed to test the virulence of bacterial lung pathogens. Because non-mammalian models have less ethical and cost constraints as a subjects for experimentation, in some cases would be appropriated to include these models as valuable tools to explore host–pathogen interactions. Numerous scientific data have been argued to the more extensive use of several kinds of alternative models, such as, the vertebrate zebrafish (Danio rerio), and non-vertebrate insects and nematodes (e.g., Caenorhabditis elegans) in the study of diverse infectious agents that affect humans. Here, we review the use of these vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favor of the use of these alternative animal models of infection to reveal the molecular signatures of host–pathogen interactions. PMID:25699030

  2. Molecular Epidemiologic Typing Systems of Bacterial Pathogens: Current Issues and Perpectives

    Directory of Open Access Journals (Sweden)

    Struelens Marc J

    1998-01-01

    Full Text Available The epidemiologic typing of bacterial pathogens can be applied to answer a number of different questions: in case of outbreak, what is the extent and mode of transmission of epidemic clone(s ? In case of long-term surveillance, what is the prevalence over time and the geographic spread of epidemic and endemic clones in the population? A number of molecular typing methods can be used to classify bacteria based on genomic diversity into groups of closely-related isolates (presumed to arise from a common ancestor in the same chain of transmission and divergent, epidemiologically-unrelated isolates (arising from independent sources of infection. Ribotyping, IS-RFLP fingerprinting, macrorestriction analysis of chromosomal DNA and PCR-fingerprinting using arbitrary sequence or repeat element primers are useful methods for outbreak investigations and regional surveillance. Library typing systems based on multilocus sequence-based analysis and strain-specific probe hybridization schemes are in development for the international surveillance of major pathogens like Mycobacterium tuberculosis. Accurate epidemiological interpretation of data obtained with molecular typing systems still requires additional research on the evolution rate of polymorphic loci in bacterial pathogens.

  3. Short chain and polyunsaturated fatty acids in host gut health and foodborne bacterial pathogen inhibition.

    Science.gov (United States)

    Peng, Mengfei; Biswas, Debabrata

    2017-12-12

    As a major source of microbes and their numerous beneficial effects, the gut microflora/microbiome is intimately linked to human health and disease. The exclusion of enteric pathogens by these commensal microbes partially depends upon the production of bioactive compounds such as short-chain fatty acids (SCFAs) and polyunsaturated fatty acids (PUFAs). These key intestinal microbial byproducts are crucial to the maintenance of a healthy gut microbial community. Moreover, SCFAs and PUFAs play multiple critical roles in host defense and immunity, including anti-cancer, anti-inflammation, and anti-oxidant activities, as well as out-competition of enteric bacterial pathogens. In this review article, we hereby aim to highlight the importance of SCFAs and PUFAs and the microbes involved in production of these beneficial intestinal components, and their biological functions, specifically as to their immunomodulation and interactions with enteric bacterial pathogens. Finally, we also advance potential applications of these fatty acids with regards to food safety and human gut health.

  4. An Overview of the Control of Bacterial Pathogens in Cattle Manure

    Directory of Open Access Journals (Sweden)

    Christy E. Manyi-Loh

    2016-08-01

    Full Text Available Cattle manure harbors microbial constituents that make it a potential source of pollution in the environment and infections in humans. Knowledge of, and microbial assessment of, manure is crucial in a bid to prevent public health and environmental hazards through the development of better management practices and policies that should govern manure handling. Physical, chemical and biological methods to reduce pathogen population in manure do exist, but are faced with challenges such as cost, odor pollution, green house gas emission, etc. Consequently, anaerobic digestion of animal manure is currently one of the most widely used treatment method that can help to salvage the above-mentioned adverse effects and in addition, produces biogas that can serve as an alternative/complementary source of energy. However, this method has to be monitored closely as it could be fraught with challenges during operation, caused by the inherent characteristics of the manure. In addition, to further reduce bacterial pathogens to a significant level, anaerobic digestion can be combined with other methods such as thermal, aerobic and physical methods. In this paper, we review the bacterial composition of cattle manure as well as methods engaged in the control of pathogenic microbes present in manure and recommendations that need to be respected and implemented in order to prevent microbial contamination of the environment, animals and humans.

  5. Inactivation of selected bacterial pathogens in dairy cattle manure by mesophilic anaerobic digestion (balloon type digester).

    Science.gov (United States)

    Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael

    2014-07-14

    Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.

  6. Genetic diversity of citrus bacterial canker pathogens preserved in herbarium specimens.

    Science.gov (United States)

    Li, Wenbin; Song, Qijian; Brlansky, Ronald H; Hartung, John S

    2007-11-20

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) was first documented in India and Java in the mid 19th century. Since that time, the known distribution of the disease has steadily increased. Concurrent with the dispersion of the pathogen, the diversity of described strains continues to increase, with novel strains appearing in Saudi Arabia, Iran, and Florida in the last decade. Herbarium specimens of infected plants provide an historical record documenting both the geographic distribution and genetic diversity of the pathogen in the past. However, no method was available to assess the genetic diversity within these herbarium samples. We have developed a method, insertion event scanning (IES), and applied the method to characterize the diversity present within CBC populations documented as herbarium specimens over the past century. IES is based on the specific amplification of junction fragments that define insertion events. The potential for IES in current forensic applications is demonstrated by finding an exact match of pathogen genotypes preserved in herbarium specimens from Japan and Florida, demonstrating the source of the original outbreak of citrus canker in Florida in 1911. IES is a very sensitive technique for differentiating bacterial strains and can be applied to any of the several hundred bacteria for which full genomic sequence data are available.

  7. Avoidance and Subversion of Eukaryotic Homeostatic Autophagy Mechanisms by Bacterial Pathogens.

    Science.gov (United States)

    Miller, Cheryl; Celli, Jean

    2016-08-28

    Autophagy is a conserved lysosomal recycling process, which maintains cellular homeostasis during stress and starvation conditions by degrading and recycling proteins, lipids, and carbohydrates, ultimately increasing nutrient availability in eukaryotes. An additional function of autophagy, termed xenophagy, is to detect, capture, and destroy invading microorganisms, such as viruses, bacteria, and protozoa, providing autophagy with a role in innate immunity. Many intracellular pathogens have, however, developed mechanisms to avoid xenophagy and have evolved strategies to take advantage of select autophagic processes to undergo their intracellular life cycle. This review article will discuss the molecular mechanisms used by the intracellular bacterial pathogens Francisella spp. and Brucella spp. to manipulate components of the autophagic pathway, promoting cytosolic growth in the case of Francisella spp. and facilitating cellular egress and cell-to-cell spread in the case of Brucella spp. These examples highlight how successful, highly infectious bacterial pathogens avoid or subvert host autophagy mechanisms normally employed to maintain eukaryotic homeostasis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Identification and Characterization of Novel Biocontrol Bacterial

    Directory of Open Access Journals (Sweden)

    Young Cheol Kim

    2014-09-01

    Full Text Available Because bacterial isolates from only a few genera have been developed commercially as biopesticides, discovery and characterization of novel bacterial strains will be a key to market expansion. Our previous screen using plant bioassays identified 24 novel biocontrol isolates representing 12 different genera. In this study, we characterized the 3 isolates showing the best biocontrol activities. The isolates were Pantoea dispersa WCU35, Proteus myxofaciens WCU244, and Exiguobacterium acetylicum WCU292 based on 16S rRNA sequence analysis. The isolates showed differential production of extracellular enzymes, antimicrobial activity against various fungal or bacterial plant pathogens, and induced systemic resistance activity against tomato gray mold disease caused by Botrytis cinerea. E. acetylicum WCU292 lacked strong in vitro antimicrobial activity against plant pathogens, but induced systemic resistance against tomato gray mold disease. These results confirm that the trait of biological control is found in a wide variety of bacterial genera

  9. Possibilities of avoidance and control of bacterial plant diseases when using pathogen-tested (certified) or - treated planting material

    NARCIS (Netherlands)

    Janse, J.; Wenneker, M.

    2002-01-01

    Testing of planting material for freedom from phytopathogenic bacteria is an important, although not exclusive, method for control of bacterial diseases of plants. Ideally, pathogen-free or pathogen-/disease-resistant planting material is desirable, but this situation is not always possible on a

  10. Diagnostic clinical and laboratory findings in response to predetermining bacterial pathogen: data from the Meningitis Registry.

    Directory of Open Access Journals (Sweden)

    Maria Karanika

    Full Text Available BACKGROUND: Childhood meningitis continues to be an important cause of mortality in many countries. The search for rapid diagnosis of acute bacterial meningitis has lead to the further exploration of prognostic factors. This study was scheduled in an attempt to analyze various clinical symptoms as well as rapid laboratory results and provide an algorithm for the prediction of specific bacterial aetiology of childhood bacterial meningitis. METHODOLOGY AND PRINCIPAL FINDINGS: During the 32 year period, 2477 cases of probable bacterial meningitis (BM were collected from the Meningitis Registry (MR. Analysis was performed on a total of 1331 confirmed bacterial meningitis cases of patients aged 1 month to 14 years. Data was analysed using EPI INFO (version 3.4.3-CDC-Atlanta and SPSS (version 15.0-Chicago software. Statistically significant (p or = 15000/microL (OR 2.19 with a PPV of 77.8% (95%CI 40.0-97.2. For the diagnosis of Haemophilus influenzae, the most significant group of diagnostic criteria included, absence of haemorrhagic rash (OR 13.61, age > or = 1 year (OR 2.04, absence of headache (OR 3.01, CSF Glu < 40 mg/dL (OR 3.62 and peripheral WBC < 15,000/microL (OR 1.74 with a PPV of 58.5% (95%CI 42.1-73.7. CONCLUSIONS: The use of clinical and laboratory predictors for the assessment of the causative bacterial pathogen rather than just for predicting outcome of mortality seems to be a useful tool in the clinical management and specific treatment of BM. These findings should be further explored and studied.

  11. Detection of human bacterial pathogens in ticks collected from Louisiana black bears (Ursus americanus luteolus).

    Science.gov (United States)

    Leydet, Brian F; Liang, Fang-Ting

    2013-04-01

    There are 4 major human-biting tick species in the northeastern United States, which include: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis. The black bear is a large mammal that has been shown to be parasitized by all the aforementioned ticks. We investigated the bacterial infections in ticks collected from Louisiana black bears (Ursus americanus subspecies luteolus). Eighty-six ticks were collected from 17 black bears in Louisiana from June 2010 to March 2011. All 4 common human-biting tick species were represented. Each tick was subjected to polymerase chain reaction (PCR) targeting select bacterial pathogens and symbionts. Bacterial DNA was detected in 62% of ticks (n=53). Rickettsia parkeri, the causative agent of an emerging spotted fever group rickettsiosis, was identified in 66% of A. maculatum, 28% of D. variabilis, and 11% of I. scapularis. The Lyme disease bacterium, Borrelia burgdorferi, was detected in 2 I. scapularis, while one A. americanum was positive for Borrelia bissettii, a putative human pathogen. The rickettsial endosymbionts Candidatus Rickettsia andeanae, rickettsial endosymbiont of I. scapularis, and Rickettsia amblyommii were detected in their common tick hosts at 21%, 39%, and 60%, respectively. All ticks were PCR-negative for Anaplasma phagocytophilum, Ehrlichia spp., and Babesia microti. This is the first reported detection of R. parkeri in vector ticks in Louisiana; we also report the novel association of R. parkeri with I. scapularis. Detection of both R. parkeri and B. burgdorferi in their respective vectors in Louisiana demands further investigation to determine potential for human exposure to these pathogens. Copyright © 2013 Elsevier GmbH. All rights reserved.

  12. Arabidopsis nonhost resistance gene PSS1 confers immunity against an oomycete and a fungal pathogen but not a bacterial pathogen that cause diseases in soybean

    Directory of Open Access Journals (Sweden)

    Sumit Rishi

    2012-06-01

    Full Text Available Abstract Background Nonhost resistance (NHR provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. Three Arabidopsis thaliana PEN (penetration deficient genes, PEN1, 2 and 3 have been shown to provide NHR against the barley pathogen Blumeria graminis f. sp. hordei at the prehaustorial level. Arabidopsis pen1-1 mutant lacking the PEN1 gene is penetrated by the hemibiotrophic oomycete pathogen Phytophthora sojae, the causal organism of the root and stem rot disease in soybean. We investigated if there is any novel nonhost resistance mechanism in Arabidopsis against the soybean pathogen, P. sojae. Results The P.sojaesusceptible (pss 1 mutant was identified by screening a mutant population created in the Arabidopsis pen1-1 mutant that lacks penetration resistance against the non adapted barley biotrophic fungal pathogen, Blumeria graminis f. sp. hordei. Segregation data suggested that PEN1 is not epistatic to PSS1. Responses of pss1 and pen1-1 to P. sojae invasion were distinct and suggest that PSS1 may act at both pre- and post-haustorial levels, while PEN1 acts at the pre-haustorial level against this soybean pathogen. Therefore, PSS1 encodes a new form of nonhost resistance. The pss1 mutant is also infected by the necrotrophic fungal pathogen, Fusarium virguliforme, which causes sudden death syndrome in soybean. Thus, a common NHR mechanism is operative in Arabidopsis against both hemibiotrophic oomycetes and necrotrophic fungal pathogens that are pathogenic to soybean. However, PSS1 does not play any role in immunity against the bacterial pathogen, Pseudomonas syringae pv. glycinea, that causes bacterial blight in soybean. We mapped PSS1 to a region very close to the southern telomere of chromosome 3 that carries no known disease resistance genes. Conclusions The study revealed that Arabidopsis PSS1 is a novel nonhost resistance gene that confers a new form of

  13. Arabidopsis nonhost resistance gene PSS1 confers immunity against an oomycete and a fungal pathogen but not a bacterial pathogen that cause diseases in soybean.

    Science.gov (United States)

    Sumit, Rishi; Sahu, Binod B; Xu, Min; Sandhu, Devinder; Bhattacharyya, Madan K

    2012-06-13

    Nonhost resistance (NHR) provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. Three Arabidopsis thaliana PEN (penetration deficient) genes, PEN1, 2 and 3 have been shown to provide NHR against the barley pathogen Blumeria graminis f. sp. hordei at the prehaustorial level. Arabidopsis pen1-1 mutant lacking the PEN1 gene is penetrated by the hemibiotrophic oomycete pathogen Phytophthora sojae, the causal organism of the root and stem rot disease in soybean. We investigated if there is any novel nonhost resistance mechanism in Arabidopsis against the soybean pathogen, P. sojae. The P.sojaesusceptible (pss) 1 mutant was identified by screening a mutant population created in the Arabidopsis pen1-1 mutant that lacks penetration resistance against the non adapted barley biotrophic fungal pathogen, Blumeria graminis f. sp. hordei. Segregation data suggested that PEN1 is not epistatic to PSS1. Responses of pss1 and pen1-1 to P. sojae invasion were distinct and suggest that PSS1 may act at both pre- and post-haustorial levels, while PEN1 acts at the pre-haustorial level against this soybean pathogen. Therefore, PSS1 encodes a new form of nonhost resistance. The pss1 mutant is also infected by the necrotrophic fungal pathogen, Fusarium virguliforme, which causes sudden death syndrome in soybean. Thus, a common NHR mechanism is operative in Arabidopsis against both hemibiotrophic oomycetes and necrotrophic fungal pathogens that are pathogenic to soybean. However, PSS1 does not play any role in immunity against the bacterial pathogen, Pseudomonas syringae pv. glycinea, that causes bacterial blight in soybean. We mapped PSS1 to a region very close to the southern telomere of chromosome 3 that carries no known disease resistance genes. The study revealed that Arabidopsis PSS1 is a novel nonhost resistance gene that confers a new form of nonhost resistance against both a hemibiotrophic oomycete

  14. Contribution of bacterial pathogens to evoking serological disease markers and aggravating disease activity in rheumatoid arthritis

    Science.gov (United States)

    Waritani, Takaki; Fukai, Richio; Shionoya, Hiroshi; Itoh, Hiroshi

    2018-01-01

    Commensal bacteria and their pathogenic components in the gastrointestinal tract and oral cavity may play pathological roles in autoimmune diseases. To study the possible involvement of bacterial pathogens in autoimmune diseases, IgG and IgA antibodies against pathogenic components produced by three strains of commensal bacteria, Escherichia coli-lipopolysaccharide (E. coli-LPS), Porphyromonas gingivalis-LPS (Pg-LPS) and peptidoglycan polysaccharide (PG-PS) from Streptococcus pyogenes, were determined by an improved ELISA system for sera from two groups of patients with rheumatoid arthritis (RA), who met rapid radiographic progression (RRP) criteria and non-RRP, and compared to normal (NL) controls. Antibody responses to these bacterial pathogens are unique and consistent in individuals, and no fundamental difference was observed between RA and NL controls. Despite the similar antibody responses to pathogens, lower IgG or higher IgA and consequent higher IgA/IgG antibody ratio among the patients with RA related to disease marker levels and disease activity. Peculiarly, the IgA/IgG anti-Pg-LPS antibody ratio resulted from lower IgG and higher IgA antibody responses to Pg-LPS strongly correlated not only with rheumatoid factor (RF), but also correlated with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and disease activity score of 28 joints with ESR (DAS28-ESR) in the RRP group. In contrast, the IgA/IgG anti-E. coli-LPS and anti-PG-PS antibody ratio correlated or tended to correlate with RF, ESR, CRP, and DAS28-ESR in the non-RRP group, whereas either the IgG or IgA anti-Pg-LPS antibody levels and consequent IgA/IgG anti-Pg-LPS antibody ratio did not correlate with any clinical marker levels in this group. Notably, anti-circular-citrullinated peptide (CCP) antibody levels, which did not correlate with either IgG or IgA antibody levels to any pathogens, did not correlate with severity of arthritis in both RRP and non-RRP. Taken together, we propose

  15. Contribution of bacterial pathogens to evoking serological disease markers and aggravating disease activity in rheumatoid arthritis.

    Science.gov (United States)

    Terato, Kuniaki; Waritani, Takaki; Fukai, Richio; Shionoya, Hiroshi; Itoh, Hiroshi; Katayama, Kou

    2018-01-01

    Commensal bacteria and their pathogenic components in the gastrointestinal tract and oral cavity may play pathological roles in autoimmune diseases. To study the possible involvement of bacterial pathogens in autoimmune diseases, IgG and IgA antibodies against pathogenic components produced by three strains of commensal bacteria, Escherichia coli-lipopolysaccharide (E. coli-LPS), Porphyromonas gingivalis-LPS (Pg-LPS) and peptidoglycan polysaccharide (PG-PS) from Streptococcus pyogenes, were determined by an improved ELISA system for sera from two groups of patients with rheumatoid arthritis (RA), who met rapid radiographic progression (RRP) criteria and non-RRP, and compared to normal (NL) controls. Antibody responses to these bacterial pathogens are unique and consistent in individuals, and no fundamental difference was observed between RA and NL controls. Despite the similar antibody responses to pathogens, lower IgG or higher IgA and consequent higher IgA/IgG antibody ratio among the patients with RA related to disease marker levels and disease activity. Peculiarly, the IgA/IgG anti-Pg-LPS antibody ratio resulted from lower IgG and higher IgA antibody responses to Pg-LPS strongly correlated not only with rheumatoid factor (RF), but also correlated with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and disease activity score of 28 joints with ESR (DAS28-ESR) in the RRP group. In contrast, the IgA/IgG anti-E. coli-LPS and anti-PG-PS antibody ratio correlated or tended to correlate with RF, ESR, CRP, and DAS28-ESR in the non-RRP group, whereas either the IgG or IgA anti-Pg-LPS antibody levels and consequent IgA/IgG anti-Pg-LPS antibody ratio did not correlate with any clinical marker levels in this group. Notably, anti-circular-citrullinated peptide (CCP) antibody levels, which did not correlate with either IgG or IgA antibody levels to any pathogens, did not correlate with severity of arthritis in both RRP and non-RRP. Taken together, we propose

  16. A Bacteriophage Capsid Protein Is an Inhibitor of a Conserved Transcription Terminator of Various Bacterial Pathogens.

    Science.gov (United States)

    Ghosh, Gairika; Reddy, Jayavardhana; Sambhare, Susmit; Sen, Ranjan

    2018-01-01

    Rho is a hexameric molecular motor that functions as a conserved transcription terminator in the majority of bacterial species and is a potential drug target. Psu is a bacteriophage P4 capsid protein that inhibits Escherichia coli Rho by obstructing its ATPase and translocase activities. In this study, we explored the anti-Rho activity of Psu for Rho proteins from different pathogens. Sequence alignment and homology modeling of Rho proteins from pathogenic bacteria revealed the conserved nature of the Psu-interacting regions in all these proteins. We chose Rho proteins from various pathogens, including Mycobacterium smegmatis , Mycobacterium bovis , Mycobacterium tuberculosis , Xanthomonas campestris , Xanthomonas oryzae , Corynebacterium glutamicum , Vibrio cholerae , Salmonella enterica , and Pseudomonas syringae The purified recombinant Rho proteins of these organisms showed variable rates of ATP hydrolysis on poly(rC) as the substrate and were capable of releasing RNA from the E. coli transcription elongation complexes. Psu was capable of inhibiting these two functions of all these Rho proteins. In vivo pulldown assays revealed direct binding of Psu with many of these Rho proteins. In vivo expression of psu induced killing of M. smegmatis , M. bovis , X. campestris , and E. coli expressing S. enterica Rho indicating Psu-induced inhibition of Rho proteins of these strains under physiological conditions. We propose that the "universal" inhibitory function of the Psu protein against the Rho proteins from both Gram-negative and Gram-positive bacteria could be useful for designing peptides with antimicrobial functions and that these peptides could contribute to synergistic antibiotic treatment of the pathogens by compromising the Rho functions. IMPORTANCE Bacteriophage-derived protein factors modulating different bacterial processes could be converted into unique antimicrobial agents. Bacteriophage P4 capsid protein Psu is an inhibitor of the E. coli transcription

  17. Quorum-sensing blockade as a strategy for enhancing host defences against bacterial pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    rise to a new 'drug target rush'. Recently, QS has been shown to be involved in the development of tolerance to various antimicrobial treatments and immune modulation. The regulation of virulence via QS confers a strategic advantage over host defences. Consequently, a drug capable of blocking QS......Conventional antibiotics target the growth and the basal life processes of bacteria leading to growth arrest and cell death. The selective force that is inherently linked to this mode of action eventually selects out antibiotic-resistant variants. The most obvious alternative to antibiotic...... is likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi-antibiotic...

  18. Antibacterial activity of some Indian ayurvedic preparations against enteric bacterial pathogens

    Directory of Open Access Journals (Sweden)

    D H Tambekar

    2011-01-01

    Full Text Available In Ayurveda, various herbal preparations are clinically used to prevent or cure infectious diseases. Herbal preparations such as Triphala churna, Hareetaki churna, Dashmula churna, Manjistadi churna, Sukhsarak churna, Ajmodadi churna, Shivkshar pachan churna, Mahasudarshan churna, Swadist Virechan churna and Pipramool churna were investigated by preparing their organic solvent extract for antibacterial potential against enteric bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Enterobacter aerogenes, Pseudomonas aeruginosa, Bacillus subtilis, Klebsiella pneumoniae, Salmonella typhi, Staphylococcus epidermidis, Salmonella typhimurium and Proteus vulgaris, respectively. In the present study, Triphala churna, Hareetaki churna, Dashmula churna were potent antibacterial agents against S. epidermidis, P. vulgaris, S. aureus, E. coli, P. aeruginosa and S. typhi. The study supports the use of these herbal preparations not only as dietary supplements but also as agents to prevent or control enteric bacterial infections.

  19. Enterobacter aerogenes and Enterobacter cloacae; versatile bacterial pathogens confronting antibiotic treatment

    Science.gov (United States)

    Davin-Regli, Anne; Pagès, Jean-Marie

    2015-01-01

    Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution. PMID:26042091

  20. Active Transport of Phosphorylated Carbohydrates Promotes Intestinal Colonization and Transmission of a Bacterial Pathogen.

    Directory of Open Access Journals (Sweden)

    Brandon Sit

    2015-08-01

    Full Text Available Efficient acquisition of extracellular nutrients is essential for bacterial pathogenesis, however the identities and mechanisms for transport of many of these substrates remain unclear. Here, we investigate the predicted iron-binding transporter AfuABC and its role in bacterial pathogenesis in vivo. By crystallographic, biophysical and in vivo approaches, we show that AfuABC is in fact a cyclic hexose/heptose-phosphate transporter with high selectivity and specificity for a set of ubiquitous metabolites (glucose-6-phosphate, fructose-6-phosphate and sedoheptulose-7-phosphate. AfuABC is conserved across a wide range of bacterial genera, including the enteric pathogens EHEC O157:H7 and its murine-specific relative Citrobacter rodentium, where it lies adjacent to genes implicated in sugar sensing and acquisition. C. rodentium ΔafuA was significantly impaired in an in vivo murine competitive assay as well as its ability to transmit infection from an afflicted to a naïve murine host. Sugar-phosphates were present in normal and infected intestinal mucus and stool samples, indicating that these metabolites are available within the intestinal lumen for enteric bacteria to import during infection. Our study shows that AfuABC-dependent uptake of sugar-phosphates plays a critical role during enteric bacterial infection and uncovers previously unrecognized roles for these metabolites as important contributors to successful pathogenesis.

  1. Contamination of knives and graters by bacterial foodborne pathogens during slicing and grating of produce.

    Science.gov (United States)

    Erickson, Marilyn C; Liao, Jean; Cannon, Jennifer L; Ortega, Ynes R

    2015-12-01

    Poor hygiene and improper food preparation practices in consumers' homes have previously been demonstrated as contributing to foodborne diseases. To address potential cross-contamination by kitchen utensils in the home, a series of studies was conducted to determine the extent to which the use of a knife or grater on fresh produce would lead to the utensil's contamination with Escherichia coli O157:H7 or Salmonella enterica. When shredding inoculated carrots (ca. 5.3 log CFU/carrot), all graters became contaminated and the number of E. coli O157:H7 present on the utensil was significantly greater than Salmonella (p Contamination of knives after slicing inoculated produce (4.9-5.4 log CFU/produce item) could only be detected by enrichment culture. After slicing tomatoes, honeydew melons, strawberries, cucumbers, and cantaloupes, the average prevalence of knife contamination by the two pathogens was 43%, 17%, 15%, 7%, and 3%, respectively. No significant increase in the incidence or level of contamination occurred on the utensils when residues were present (p > 0.05); however, subsequent contamination of 7 produce items processed with the contaminated utensils did occur. These results highlight the necessity of proper sanitization of these utensils when used in preparation of raw produce. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Origin and Proliferation of Multiple-Drug Resistance in Bacterial Pathogens

    Science.gov (United States)

    Chang, Hsiao-Han; Cohen, Ted; Grad, Yonatan H.; Hanage, William P.; O'Brien, Thomas F.

    2015-01-01

    SUMMARY Many studies report the high prevalence of multiply drug-resistant (MDR) strains. Because MDR infections are often significantly harder and more expensive to treat, they represent a growing public health threat. However, for different pathogens, different underlying mechanisms are traditionally used to explain these observations, and it is unclear whether each bacterial taxon has its own mechanism(s) for multidrug resistance or whether there are common mechanisms between distantly related pathogens. In this review, we provide a systematic overview of the causes of the excess of MDR infections and define testable predictions made by each hypothetical mechanism, including experimental, epidemiological, population genomic, and other tests of these hypotheses. Better understanding the cause(s) of the excess of MDR is the first step to rational design of more effective interventions to prevent the origin and/or proliferation of MDR. PMID:25652543

  3. Comparative Resistance of Bacterial Foodborne Pathogens to Non-thermal Technologies for Food Preservation

    Science.gov (United States)

    Cebrián, Guillermo; Mañas, Pilar; Condón, Santiago

    2016-01-01

    In this paper the resistance of bacterial foodborne pathogens to manosonication (MS), pulsed electric fields (PEFs), high hydrostatic pressure (HHP), and UV-light (UV) is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni) would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could also be

  4. COMPARATIVE RESISTANCE OF BACTERIAL FOODBORNE PATHOGENS TO NON-THERMAL TECHNOLOGIES FOR FOOD PRESERVATION

    Directory of Open Access Journals (Sweden)

    Guillermo eCebrián

    2016-05-01

    Full Text Available In this paper the resistance of bacterial foodborne pathogens to manosonication (MS, pulsed electric fields (PEF, high hydrostatic pressure (HHP and UV-light (UV is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could

  5. Genomic Epidemiology: Whole-Genome-Sequencing–Powered Surveillance and Outbreak Investigation of Foodborne Bacterial Pathogens

    DEFF Research Database (Denmark)

    Deng, Xiangyu; den Bakker, Henk C.; Hendriksen, Rene S.

    2016-01-01

    As we are approaching the twentieth anniversary of PulseNet, a network of public health and regulatory laboratories that has changed the landscape of foodborne illness surveillance through molecular subtyping, public health microbiology is undergoing another transformation brought about by so......-called next-generation sequencing (NGS) technologies that have made whole-genome sequencing (WGS) of foodborne bacterial pathogens a realistic and superior alternative to traditional subtyping methods. Routine, real-time, and widespread application of WGS in food safety and public health is on the horizon...

  6. Subversion of actin dynamics by EspM effectors of attaching and effacing bacterial pathogens

    OpenAIRE

    Arbeloa, Ana; Bulgin, Richard R; MacKenzie, Georgina; Shaw, Robert K; Pallen, Mark J; Crepin, Valerie F; Berger, Cedric N; Frankel, Gad

    2008-01-01

    Rho GTPases are common targets of bacterial toxins and type III secretion system effectors. IpgB1 and IpgB2 of Shigella and Map of enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli were recently grouped together on the basis that they share a conserved WxxxE motif. In this study, we characterized six WxxxE effectors from attaching and effacing pathogens: TrcA and EspM1 of EPEC strain B171, EspM1 and EspM2 of EHEC strain Sakai and EspM2 and EspM3 of Citrobacter rodentium. W...

  7. Spaceflight and Simulated Microgravity Increases Virulence of the Known Bacterial Pathogen S. Marcescens

    Science.gov (United States)

    Clemens-Grisham, Rachel Andrea; Bhattacharya, Sharmila; Wade, William

    2016-01-01

    After spaceflight, the number of immune cells is reduced in humans. In other research models, including Drosophila, not only is there a reduction in the number of plasmatocytes, but expression of immune-related genes is also changed after spaceflight. These observations suggest that the immune system is compromised after exposure to microgravity. It has also been reported that there is a change in virulence of some bacterial pathogens after spaceflight. We recently observed that samples of gram-negative S. marcescens retrieved from spaceflight is more virulent than ground controls, as determined by reduced survival and increased bacterial growth in the host. We were able to repeat this finding of increased virulence after exposure to simulated microgravity using the rotating wall vessel, a ground based analog to microgravity. With the ground and spaceflight samples, we looked at involvement of the Toll and Imd pathways in the Drosophila host in fighting infection by ground and spaceflight samples. We observed that Imd-pathway mutants were more susceptible to infection by the ground bacterial samples, which aligns with the known role of this pathway in fighting infections by gram-negative bacteria. When the Imd-pathway mutants were infected with the spaceflight sample, however, they exhibited the same susceptibility as seen with the ground control bacteria. Interestingly, all mutant flies show the same susceptibility to the spaceflight bacterial sample as do wild type flies. This suggests that neither humoral immunity pathway is effectively able to counter the increased pathogenicity of the space-flown S. marcescens bacteria.

  8. A Bacterial Pathogen Targets a Host Rab-Family GTPase Defense Pathway with a GAP.

    Science.gov (United States)

    Spanò, Stefania; Gao, Xiang; Hannemann, Sebastian; Lara-Tejero, María; Galán, Jorge E

    2016-02-10

    Cell-autonomous defense mechanisms are potent strategies that protect individual cells against intracellular pathogens. The Rab-family GTPase Rab32 was previously shown to restrict the intracellular human pathogen Salmonella Typhi, but its potential broader role in antimicrobial defense remains unknown. We show that Rab32 represents a general cell-autonomous, antimicrobial defense that is counteracted by two Salmonella effectors. Mice lacking Rab-32 or its nucleotide exchange factor BLOC-3 are permissive to S. Typhi infection and exhibit increased susceptibility to S. Typhimurium. S. Typhimurium counters this defense pathway by delivering two type III secretion effectors, SopD2, a Rab32 GAP, and GtgE, a specific Rab32 protease. An S. Typhimurium mutant strain lacking these two effectors exhibits markedly reduced virulence, which is fully restored in BLOC-3-deficient mice. These results demonstrate that a cell-autonomous, Rab32-dependent host defense pathway plays a central role in the defense against vacuolar pathogens and describe a mechanism evolved by a bacterial pathogen to counter it. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Transport of selected bacterial pathogens in agricultural soil and quartz sand.

    Science.gov (United States)

    Schinner, Tim; Letzner, Adrian; Liedtke, Stefan; Castro, Felipe D; Eydelnant, Irwin A; Tufenkji, Nathalie

    2010-02-01

    The protection of groundwater supplies from microbial contamination necessitates a solid understanding of the key factors controlling the migration and retention of pathogenic organisms through the subsurface environment. The transport behavior of five waterborne pathogens was examined using laboratory-scale columns packed with clean quartz at two solution ionic strengths (10 mM and 30 mM). Escherichia coli O157:H7 and Yersinia enterocolitica were selected as representative Gram-negative pathogens, Enterococcus faecalis was selected as a representative Gram-positive organism, and two cyanobacteria (Microcystis aeruginosa and Anabaena flos-aquae) were also studied. The five organisms exhibit differing attachment efficiencies to the quartz sand. The surface (zeta) potential of the microorganisms was characterized over a broad range of pH values (2-8) at two ionic strengths (10 mM and 30 mM). These measurements are used to evaluate the observed attachment behavior within the context of the DLVO theory of colloidal stability. To better understand the possible link between bacterial transport in model quartz sand systems and natural soil matrices, additional experiments were conducted with two of the selected organisms using columns packed with loamy sand obtained from an agricultural field. This investigation highlights the need for further characterization of waterborne pathogen surface properties and transport behavior over a broader range of environmentally relevant conditions. Copyright 2008 Elsevier Ltd. All rights reserved.

  10. Investigating the Antimicrobial Bioactivity of Cyano bacterial Extracts on Some Plant and Human Pathogens

    International Nuclear Information System (INIS)

    El-Semary, N.A.; Osman, M.E.; Ahmed, A.S.; Botros, H.W.; Farag, A.T.

    2014-01-01

    The search for broad spectrum antimicrobial agents against microbial pathogens, as the available bioactive compounds, has decreasing efficacy and the multidrug resistance trait is spreading among pathogens. Accordingly, the study was carried out to investigate the antimicrobial bioactivity of extracts derived from a cyano bacterial strain from Egypt. The solvents used were diethyl ether, chloroform and methanol. The antimicrobial bioassay of the lipophilic fraction dissolved in diethyl ether of Synechococcus spp. (isolated from Wadi El-Natroun, Egypt) showed the highest broad spectrum bioactivity as it inhibited the growth of both plant and human pathogens. The extract was also effective on the filamentous plant pathogenic fungi Aspergillus flavus and Aspergillus niger. The effects of incubation periods, growth media and pH values on both growth and antimicrobial activity of Synechococcus spp. were investigated. Chu medium was the medium that gave the highest growth followed by BG11 medium then Oscillatoria medium and all these three media showed antibacterial activities but only BG11 showed both antibacterial and antifungal activities after 18 days of incubation. The pH value 10 proved to be the best for growth and antimicrobial activities of Synechococcus spp. in BG11 medium

  11. Simultaneous Detection of 13 Key Bacterial Respiratory Pathogens by Combination of Multiplex PCR and Capillary Electrophoresis.

    Science.gov (United States)

    Jiang, Lu Xi; Ren, Hong Yu; Zhou, Hai Jian; Zhao, Si Hong; Hou, Bo Yan; Yan, Jian Ping; Qin, Tian; Chen, Yu

    2017-08-01

    Lower respiratory tract infections continue to pose a significant threat to human health. It is important to accurately and rapidly detect respiratory bacteria. To compensate for the limits of current respiratory bacteria detection methods, we developed a combination of multiplex polymerase chain reaction (PCR) and capillary electrophoresis (MPCE) assay to detect thirteen bacterial pathogens responsible for lower respiratory tract infections, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Mycoplasma pneumoniae, Legionella spp., Bordetella pertussis, Mycobacterium tuberculosis complex, Corynebacterium diphtheriae, and Streptococcus pyogenes. Three multiplex PCR reactions were built, and the products were analyzed by capillary electrophoresis using the high-throughput DNA analyzer. The specificity of the MPCE assay was examined and the detection limit was evaluated using DNA samples from each bacterial strain and the simulative samples of each strain. This assay was further evaluated using 152 clinical specimens and compared with real-time PCR reactions. For this assay, three nested-multiplex-PCRs were used to detect these clinical specimens. The detection limits of the MPCE assay for the 13 pathogens were very low and ranged from 10-7 to 10-2 ng/μL. Furthermore, analysis of the 152 clinical specimens yielded a specificity ranging from 96.5%-100.0%, and a sensitivity of 100.0% for the 13 pathogens. This study revealed that the MPCE assay is a rapid, reliable, and high-throughput method with high specificity and sensitivity. This assay has great potential in the molecular epidemiological survey of respiratory pathogens. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  12. The Opportunistic Pathogen Serratia marcescens Utilizes Type VI Secretion To Target Bacterial Competitors ▿†

    Science.gov (United States)

    Murdoch, Sarah L.; Trunk, Katharina; English, Grant; Fritsch, Maximilian J.; Pourkarimi, Ehsan; Coulthurst, Sarah J.

    2011-01-01

    The type VI secretion system (T6SS) is the most recently described and least understood of the protein secretion systems of Gram-negative bacteria. It is widely distributed and has been implicated in the virulence of various pathogens, but its mechanism and exact mode of action remain to be defined. Additionally there have been several very recent reports that some T6SSs can target bacteria rather than eukaryotic cells. Serratia marcescens is an opportunistic enteric pathogen, a class of bacteria responsible for a significant proportion of hospital-acquired infections. We describe the identification of a functional T6SS in S. marcescens strain Db10, the first report of type VI secretion by an opportunist enteric bacterium. The T6SS of S. marcescens Db10 is active, with secretion of Hcp to the culture medium readily detected, and is expressed constitutively under normal growth conditions from a large transcriptional unit. Expression of the T6SS genes did not appear to be dependent on the integrity of the T6SS. The S. marcescens Db10 T6SS is not required for virulence in three nonmammalian virulence models. It does, however, exhibit dramatic antibacterial killing activity against several other bacterial species and is required for S. marcescens to persist in a mixed culture with another opportunist pathogen, Enterobacter cloacae. Importantly, this antibacterial killing activity is highly strain specific, with the S. marcescens Db10 T6SS being highly effective against another strain of S. marcescens with a very similar and active T6SS. We conclude that type VI secretion plays a crucial role in the competitiveness, and thus indirectly the virulence, of S. marcescens and other opportunistic bacterial pathogens. PMID:21890705

  13. Novel aptamer-linked nanoconjugate approach for detection of waterborne bacterial pathogens: an update

    Science.gov (United States)

    Singh, Gulshan; Manohar, Murli; Adegoke, Anthony Ayodeji; Stenström, Thor Axel; Shanker, Rishi

    2017-01-01

    The lack of microbiologically safe water in underdeveloped nations is the prime cause of infectious disease outbreaks. The need for the specific identification and detection of microorganisms encourages the development of advanced, rapid, sensitive and highly specific methods for the monitoring of pathogens and management of potential risk to human health. The rapid molecular assays based on detection of specific molecular signatures offer advantages over conventional methods in terms of specificity and sensitivity but require complex instrumentation and skilled personnel. Nanotechnology is an emerging area and provides a robust approach for the identification of pathogenic microorganism utilizing the peculiar properties of nanomaterials, i.e. small size (1-100 nm) and large surface area. This emerging technology promises to fulfill the urgent need of a novel strategy to enhance the bacterial identification and quantitation in the environment. In this context, the peculiar properties of gold nanoparticles, their plasmonic shifts, and changes in magnetic properties have been utilized for the simple and cost-effective detection of bacterial nucleic acids, antigens and toxins with quite improved sensitivity. One of the promising leads to develop an advance detection method might be the coupling of nucleic acid aptamers (capable of interacting specifically with bacteria, protozoa, and viruses) with nanomaterials. Such aptamer-nano conjugate can be used for the specific recognition of infectious agents in different environmental matrices. This review summarizes the application of nanotechnology in the area of pathogen detection and discusses the prospects of coupling nucleic acid aptamers with nanoparticles for the specific detection of targeted pathogens.

  14. Novel aptamer-linked nanoconjugate approach for detection of waterborne bacterial pathogens: an update

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Gulshan, E-mail: gsingh.gulshan@gmail.com [Durban University of Technology, Institute for Water and Wastewater Technology (IWWT) (South Africa); Manohar, Murli [Jamia Hamdard (Hamdard University), Department of Biochemistry (India); Adegoke, Anthony Ayodeji; Stenström, Thor Axel [Durban University of Technology, Institute for Water and Wastewater Technology (IWWT) (South Africa); Shanker, Rishi [Ahmedabad University, Division of Biological & Life Sciences, School of Arts & Sciences (India)

    2017-01-15

    The lack of microbiologically safe water in underdeveloped nations is the prime cause of infectious disease outbreaks. The need for the specific identification and detection of microorganisms encourages the development of advanced, rapid, sensitive and highly specific methods for the monitoring of pathogens and management of potential risk to human health. The rapid molecular assays based on detection of specific molecular signatures offer advantages over conventional methods in terms of specificity and sensitivity but require complex instrumentation and skilled personnel. Nanotechnology is an emerging area and provides a robust approach for the identification of pathogenic microorganism utilizing the peculiar properties of nanomaterials, i.e. small size (1–100 nm) and large surface area. This emerging technology promises to fulfill the urgent need of a novel strategy to enhance the bacterial identification and quantitation in the environment. In this context, the peculiar properties of gold nanoparticles, their plasmonic shifts, and changes in magnetic properties have been utilized for the simple and cost-effective detection of bacterial nucleic acids, antigens and toxins with quite improved sensitivity. One of the promising leads to develop an advance detection method might be the coupling of nucleic acid aptamers (capable of interacting specifically with bacteria, protozoa, and viruses) with nanomaterials. Such aptamer-nano conjugate can be used for the specific recognition of infectious agents in different environmental matrices. This review summarizes the application of nanotechnology in the area of pathogen detection and discusses the prospects of coupling nucleic acid aptamers with nanoparticles for the specific detection of targeted pathogens.

  15. Tomato Cf resistance proteins mediate recognition of cognate homologous effectors from fungi pathogenic on diots and monocots

    NARCIS (Netherlands)

    Stergiopoulos, I.; Burg, van den H.A.; Ökmen, B.; Beenen, H.G.; Liere, van S.; Kema, G.H.J.; Wit, de P.J.G.M.

    2010-01-01

    Most fungal effectors characterized so far are species-specific and facilitate virulence on a particular host plant. During infection of its host tomato, Cladosporium fulvum secretes effectors that function as virulence factors in the absence of cognate Cf resistance proteins and induce

  16. Clinical differences between respiratory viral and bacterial mono- and dual pathogen detected among Singapore military servicemen with febrile respiratory illness.

    Science.gov (United States)

    Ho, Zheng Jie Marc; Zhao, Xiahong; Cook, Alex R; Loh, Jin Phang; Ng, Sock Hoon; Tan, Boon Huan; Lee, Vernon J

    2015-07-01

    Although it is known that febrile respiratory illnesses (FRI) may be caused by multiple respiratory pathogens, there are no population-level studies describing its impact on clinical disease. Between May 2009 and October 2012, 7733 FRI patients and controls in the Singapore military had clinical data and nasal wash samples collected prospectively and sent for PCR testing. Patients with one pathogen detected (mono-pathogen) were compared with those with two pathogens (dual pathogen) for differences in basic demographics and clinical presentation. In total, 45.8% had one pathogen detected, 20.2% had two pathogens detected, 30.9% had no pathogens detected, and 3.1% had more than two pathogens. Multiple pathogens were associated with recruits, those with asthma and non-smokers. Influenza A (80.0%), influenza B (73.0%) and mycoplasma (70.6%) were most commonly associated with mono-infections, while adenovirus was most commonly associated with dual infections (62.9%). Influenza A paired with S. pneumoniae had higher proportions of chills and rigors than their respective mono-pathogens (P = 0.03, P = 0.009). H. influenzae paired with either enterovirus or parainfluenzae had higher proportions of cough with phlegm than their respective mono-pathogens. Although there were observed differences in mean proportions of body temperature, nasal symptoms, sore throat, body aches and joint pains between viral and bacterial mono-pathogens, there were few differences between distinct dual-pathogen pairs and their respective mono-pathogen counterparts. A substantial number of FRI patients have multiple pathogens detected. Observed clinical differences between patients of dual pathogen and mono-pathogen indicate the likely presence of complex microbial interactions between the various pathogens. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  17. Characterization and purification of a bacterial chlorogenic acid esterase detected during the extraction of chlorogenic acid from arbuscular mycorrhizal tomato roots.

    Science.gov (United States)

    Negrel, Jonathan; Javelle, Francine; Morandi, Dominique; Lucchi, Géraldine

    2016-12-01

    A Gram-negative bacterium able to grow using chlorogenic acid (5-caffeoylquinic acid) as sole carbon source has been isolated from the roots of tomato plants inoculated with the arbuscular mycorrhizal fungus Rhizophagus irregularis. An intracellular esterase exhibiting very high affinity (K m  = 2 μM) for chlorogenic acid has been extracted and purified by FPLC from the chlorogenate-grown cultures of this bacterium. The molecular mass of the purified esterase determined by SDS-PAGE was 61 kDa and its isoelectric point determined by chromatofocusing was 7.75. The esterase hydrolysed chlorogenic acid analogues (caffeoylshikimate, and the 4- and 3-caffeoylquinic acid isomers), feruloyl esterases substrates (methyl caffeate and methyl ferulate), and even caffeoyl-CoA in vitro but all of them were less active than chlorogenic acid, demonstrating that the esterase is a genuine chlorogenic acid esterase. It was also induced when the bacterial strain was cultured in the presence of hydroxycinnamic acids (caffeic, p-coumaric or ferulic acid) as sole carbon source, but not in the presence of simple phenolics such as catechol or protocatechuic acid, nor in the presence of organic acids such as succinic or quinic acids. The purified esterase was remarkably stable in the presence of methanol, rapid formation of methyl caffeate occurring when its activity was measured in aqueous solutions containing 10-60% methanol. Our results therefore show that this bacterial chlorogenase can catalyse the transesterification reaction previously detected during the methanolic extraction of chlorogenic acid from arbuscular mycorrhizal tomato roots. Data are presented suggesting that colonisation by Rhizophagus irregularis could increase chlorogenic acid exudation from tomato roots, especially in nutrient-deprived plants, and thus favour the growth of chlorogenate-metabolizing bacteria on the root surface or in the mycorhizosphere. Copyright © 2016 Elsevier Masson SAS. All rights

  18. Characterization of plant growth promoting traits of bacterial isolates from the rhizosphere of barley (Hordeum vulgare L.) and tomato (Solanum lycopersicon L.) grown under Fe sufficiency and deficiency.

    Science.gov (United States)

    Scagliola, M; Pii, Y; Mimmo, T; Cesco, S; Ricciuti, P; Crecchio, C

    2016-10-01

    Plant Growth Promoting Bacteria (PGPB) are considered a promising approach to replace the conventional agricultural practices, since they have been shown to affect plant nutrient-acquisition processes by influencing nutrient availability in the rhizosphere and/or those biochemical processes determining the uptake at root level of nitrogen (N), phosphorus (P), and iron (Fe), that represent the major constraints for crop productivity worldwide. We have isolated novel bacterial strains from the rhizosphere of barley (Hordeum vulgare L.) and tomato (Solanum lycopersicon L.) plants, previously grown in hydroponic solution (either Fe deficient or Fe sufficient) and subsequently transferred onto an agricultural calcareous soil. PGPB have been identified by molecular tools and characterized for their capacity to produce siderophores and indole-3-acetic acid (IAA), and to solubilize phosphate. Selected bacterial isolates, showing contemporarily high levels of the three activities investigated, were finally tested for their capacity to induce Fe reduction in cucumber roots two isolates, from barley and tomato plants under Fe deficiency, significantly increased the root Fe-chelate reductase activity; interestingly, another isolate enhanced the reduction of Fe-chelate reductase activity in cucumber plant roots, although grown under Fe sufficiency. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Gram stains: a resource for retrospective analysis of bacterial pathogens in clinical studies.

    Science.gov (United States)

    Srinivasan, Usha; Ponnaluri, Sreelatha; Villareal, Lisa; Gillespie, Brenda; Wen, Ai; Miles, Arianna; Bucholz, Brigette; Marrs, Carl F; Iyer, Ram K; Misra, Dawn; Foxman, Betsy

    2012-01-01

    We demonstrate the feasibility of using qPCR on DNA extracted from vaginal Gram stain slides to estimate the presence and relative abundance of specific bacterial pathogens. We first tested Gram stained slides spiked with a mix of 10(8) cfu/ml of Escherichia coli and 10(5) cfu/ml of Lactobacillus acidophilus. Primers were designed for amplification of total and species-specific bacterial DNA based on 16S ribosomal gene regions. Sample DNA was pre-amplified with nearly full length 16S rDNA ribosomal gene fragment, followed by quantitative PCR with genera and species-specific 16S rDNA primers. Pre-amplification PCR increased the bacterial amounts; relative proportions of Escherichia coli and Lactobacillus recovered from spiked slides remained unchanged. We applied this method to forty two archived Gram stained slides available from a clinical trial of cerclage in pregnant women at high risk of preterm birth. We found a high correlation between Nugent scores based on bacterial morphology of Lactobacillus, Gardenerella and Mobiluncus and amounts of quantitative PCR estimated genus specific DNA (rrn copies) from Gram stained slides. Testing of a convenience sample of eight paired vaginal swabs and Gram stains freshly collected from healthy women found similar qPCR generated estimates of Lactobacillus proportions from Gram stained slides and vaginal swabs. Archived Gram stained slides collected from large scale epidemiologic and clinical studies represent a valuable, untapped resource for research on the composition of bacterial communities that colonize human mucosal surfaces.

  20. Spatial and temporal occurrence of bacterial pathogens in rural water supplies, Southern Alberta, Canada

    Science.gov (United States)

    Gannon, V.; Graham, T. A.; Read, S.; Ziebell, K.; Muckle, A.; Thomas, J.; Selinger, B.; Kienzle, S.; Lapp, S. L.; Townshend, I.; Byrne, J.

    2002-12-01

    Southern Alberta has the highest rate of gastrointestinal illness in the province, and some of the highest infection rates in Canada. The region has extensive field crop irrigation system supporting a rapidly expanding animal agriculture industry. Recently, there has been much public concern about the safety and quality of water in this region, particularly with respect to drinking water supplies for farm residences and rural communities, where water treatment may be less than optimal. We have tested raw river and irrigation water in the Oldman River Basin in southern Alberta for the presence of bacterial pathogens (E. coli O157:H7 and Salmonella spp ) as well as made counts of total and faecal coliforms over the last two years (2000-2001). E. coli O157:H7 and Salmonella spp. isolations and coliform counts peak in raw water from this system during the summer months. E. coli O157:H7 was only isolated from 27/1624 (1.7%) and Salmonella was isolated from 158/1624 (9.7%) of raw water samples over the two year period. Certain sites had multiple pathogen isolations and high indicator bacteria counts in the same year and from year to year. Certain sites had multiple pathogen isolations and high indicator bacteria counts in the same year and from year to year. S. Rublislaw was the most common Salmonella serovar isolated in both years. While this serovar is rarely associated with human or animal disease in Alberta, other Salmonella serovars isolated, such as Typhimurium, are commonly disease-associated. This poster presents initial analyses of the spatial and temporal properties of pathogen occurrences in the Oldman Basin in 2000 and 2001. Seasonal variability in the occurrence of pathogens is particularly interesting and of concern. Early results demonstrate the pathogen occurrences peak during the height of the summer recreation season; posing a substantial infection risk for the public and tourism populations. Human consumption of inadequately treated water in this

  1. Inactivation of bacterial pathogenic load in compost against vermicompost of organic solid waste aiming to achieve sanitation goals: A review.

    Science.gov (United States)

    Soobhany, Nuhaa; Mohee, Romeela; Garg, Vinod Kumar

    2017-06-01

    Waste management strategies for organic residues, such as composting and vermicomposting, have been implemented in some developed and developing countries to solve the problem of organic solid waste (OSW). Yet, these biological treatment technologies do not always result in good quality compost or vermicompost with regards to sanitation capacity owing to the presence of bacterial pathogenic substances in objectionable concentrations. The presence of pathogens in soil conditioners poses a potential health hazard and their occurrence is of particular significance in composts and/or vermicomposts produced from organic materials. Past and present researches demonstrated a high-degree of agreement that various pathogens survive after the composting of certain OSW but whether similar changes in bacterial pathogenic loads arise during vermitechnology has not been thoroughly elucidated. This review garners information regarding the status of various pathogenic bacteria which survived or diffused after the composting process compared to the status of these pathogens after the vermicomposting of OSW with the aim of achieving sanitation goals. This work is also indispensable for the specification of compost quality guidelines concerning pathogen loads which would be specific to treatment technology. It was hypothesized that vermicomposting process for OSW can be efficacious in sustaining the existence of pathogenic organisms most specifically; human pathogens under safety levels. In summary, earthworms can be regarded as a way of obliterating pathogenic bacteria from OSW in a manner equivalent to earthworm gut transit mechanism which classifies vermicomposting as a promising sanitation technique in comparison to composting processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Antibacterial Activity of Polyphenolic Fraction of Kombucha Against Enteric Bacterial Pathogens.

    Science.gov (United States)

    Bhattacharya, Debanjana; Bhattacharya, Semantee; Patra, Madhu Manti; Chakravorty, Somnath; Sarkar, Soumyadev; Chakraborty, Writachit; Koley, Hemanta; Gachhui, Ratan

    2016-12-01

    The emergence of multi-drug-resistant enteric pathogens has prompted the scientist community to explore the therapeutic potentials of traditional foods and beverages. The present study was undertaken to investigate the efficacy of Kombucha, a fermented beverage of sugared black tea, against enterotoxigenic Escherichia coli, Vibrio cholerae, Shigella flexneri and Salmonella Typhimurium followed by the identification of the antibacterial components present in Kombucha. The antibacterial activity was evaluated by determining the inhibition zone diameter, minimal inhibitory concentration and minimal bactericidal concentration. Kombucha fermented for 14 days showed maximum activity against the bacterial strains. Its ethyl acetate extract was found to be the most effective upon sequential solvent extraction of the 14-day Kombucha. This potent ethyl acetate extract was then subjected to thin layer chromatography for further purification of antibacterial ingredients which led to the isolation of an active polyphenolic fraction. Catechin and isorhamnetin were detected as the major antibacterial compounds present in this polyphenolic fraction of Kombucha by High Performance Liquid Chromatography. Catechin, one of the primary antibacterial polyphenols in tea was also found to be present in Kombucha. But isorhamnetin is not reported to be present in tea, which may thereby suggest the role of fermentation process of black tea for its production in Kombucha. To the best of our knowledge, this is the first report on the presence of isorhamnetin in Kombucha. The overall study suggests that Kombucha can be used as a potent antibacterial agent against entero-pathogenic bacterial infections, which mainly is attributed to its polyphenolic content.

  3. Studies on antimicrobial and antifungal activities of ziziphus mauritiana human clinical bacterial and fungal pathogens

    International Nuclear Information System (INIS)

    Amin, A.; Shah, S.; Khan, M.A.; Khan, M.M.

    2012-01-01

    The antimicrobial and antifungal activities of crude extracts of Ziziphus mauritiana leaves were investigated against six selected bacterial (Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella pneumoniae) and one fungal pathogen (Aspel-gillus niger). The crude extract was further fractionated in butanol, choloroform, n-hexane and methanol. Agar well diffusion and agar dilution assay were employed for determination of zones of inhibition and MICs, respectively, whereas MBC was determined using broth dilution test. The butanol fraction presented encouraging antimicrobial activity (15.0%0.02), while methanol (7.03:1:0.05) and chloroform (7.0%0,05) fractions emerged with significantly low susceptibility. The n-hexane fraction was recorded as almost inactive (0%0) against all bacterial pathogens. Unlike the antibacterial activities, all fractions possessed momentous antifungal activities except the methanol fraction (0%0). The n-hexane fraction showed widest zone of inhibition (11:1:0.05) followed by butanol (8.0%0.02) and chloroform (7.0%0.02). (author)

  4. Stacking of antimicrobial genes in potato transgenic plants confers increased resistance to bacterial and fungal pathogens.

    Science.gov (United States)

    Rivero, Mercedes; Furman, Nicolás; Mencacci, Nicolás; Picca, Pablo; Toum, Laila; Lentz, Ezequiel; Bravo-Almonacid, Fernando; Mentaberry, Alejandro

    2012-01-20

    Solanum tuberosum plants were transformed with three genetic constructions expressing the Nicotiana tabacum AP24 osmotine, Phyllomedusa sauvagii dermaseptin and Gallus gallus lysozyme, and with a double-transgene construction expressing the AP24 and lysozyme sequences. Re-transformation of dermaseptin-transformed plants with the AP24/lysozyme construction allowed selection of plants simultaneously expressing the three transgenes. Potato lines expressing individual transgenes or double- and triple-transgene combinations were assayed for resistance to Erwinia carotovora using whole-plant and tuber infection assays. Resistance levels for both infection tests compared consistently for most potato lines and allowed selection of highly resistant phenotypes. Higher resistance levels were found in lines carrying the dermaseptin and lysozyme sequences, indicating that theses proteins are the major contributors to antibacterial activity. Similar results were obtained in tuber infection tests conducted with Streptomyces scabies. Plant lines showing the higher resistance to bacterial infections were challenged with Phytophthora infestans, Rhizoctonia solani and Fusarium solani. Considerable levels of resistance to each of these pathogens were evidenced employing semi-quantitative tests based in detached-leaf inoculation, fungal growth inhibition and in vitro plant inoculation. On the basis of these results, we propose that stacking of these transgenes is a promising approach to achieve resistance to both bacterial and fungal pathogens. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    Directory of Open Access Journals (Sweden)

    Jordan Lee Harris

    Full Text Available Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.

  6. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    Science.gov (United States)

    Harris, Jordan Lee; Balci, Yilmaz

    2015-01-01

    Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.

  7. The efficacy of cough plates in the identification of bacterial pathogens in children with cystic fibrosis.

    Science.gov (United States)

    Byrne, N M; O'Brien, C; Spencer, D A

    2013-10-01

    Identification of bacterial pathogens is paramount for prompt and effective treatment of respiratory exacerbations in children with cystic fibrosis (CF). This can be a challenge in non-expectorating patients as reliability of cough swabs (CS) is poor. More recently, cough plates (CP) have been reported to give high yields in some series. The aim of the study was to ascertain their effectiveness compared to CS and to assess the impact of cough strength on efficacy of CP. Non-expectorating children with CF aged 3-16 years were recruited. Baseline data was recorded and peak cough flow measured. Specimens were obtained with CP and a cough swab in a randomised order and repeated at up to four clinic visits to obtain multiple measurements. Subjects completed a short questionnaire. Number of subjects was 95, mean age 8.8±4.1 years, 45 males. Mean baseline % predicted FEV1 was 90.8±18. In total, 324 sets of specimens were collected. Pathogens were isolated in 18.2% of CS and 8% of CP. Agreement between the two specimens occurred in only 5.5% of cases. CP isolated pathogens on six occasions when the CS was negative while 40 CS were positive with a corresponding negative CP. Cough strength increased with age, and there was a trend towards older children isolating more pathogens on CP. However, this was not statistically significant. The majority of subjects preferred the CP. CP are less effective than CS in identifying respiratory pathogens in children with CF.

  8. Cladophora (Chlorophyta) spp. harbor human bacterial pathogens in nearshore water of Lake Michigan

    Science.gov (United States)

    Ishii, S.; Yan, T.; Shively, D.A.; Byappanahalli, M.N.; Whitman, R.L.; Sadowsky, M.J.

    2006-01-01

    Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attachedCladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC),Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. WhileShigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 × 103 cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 × 102 Campylobacter cells/gCladophora in 60 to 100% of lake- and ditchside samples. The Campylobacterdensities were significantly higher (P pathogenic bacteria in Lake Michigan and that the association of these bacteria with Cladophora warrants additional studies to assess the potential health impact on beach users.

  9. Nucleic Acid-Based Detection and Identification of Bacterial and Fungal Plant Pathogens - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, Mark T.

    2001-03-13

    The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysis of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.

  10. Analysis of Sequenced Genomes of Xanthomonas perforans Identifies Candidate Targets for Resistance Breeding in Tomato.

    Science.gov (United States)

    Timilsina, Sujan; Abrahamian, Peter; Potnis, Neha; Minsavage, Gerald V; White, Frank F; Staskawicz, Brian J; Jones, Jeffrey B; Vallad, Gary E; Goss, Erica M

    2016-10-01

    Bacterial disease management is a challenge for modern agriculture due to rapid changes in pathogen populations. Genome sequences for hosts and pathogens provide detailed information that facilitates effector-based breeding strategies. Tomato genotypes have gene-for-gene resistance to the bacterial spot pathogen Xanthomonas perforans. The bacterial spot populations in Florida shifted from tomato race 3 to 4, such that the corresponding tomato resistance gene no longer recognizes the effector protein AvrXv3. Genome sequencing showed variation in effector profiles among race 4 strains collected in 2006 and 2012 and compared with a race 3 strain collected in 1991. We examined variation in putative targets of resistance among Florida strains of X. perforans collected from 1991 to 2006. Consistent with race change, avrXv3 was present in race 3 strains but nonfunctional in race 4 strains due to multiple independent mutations. Effectors xopJ4 and avrBs2 were unchanged in all strains. The effector avrBsT was absent in race 3 strains collected in the 1990s but present in race 3 strains collected in 2006 and nearly all race 4 strains. These changes in effector profiles suggest that xopJ4 and avrBsT are currently the best targets for resistance breeding against bacterial spot in tomato.

  11. Co-transcriptomic Analysis by RNA Sequencing to Simultaneously Measure Regulated Gene Expression in Host and Bacterial Pathogen

    KAUST Repository

    Ravasi, Timothy

    2016-01-24

    Intramacrophage pathogens subvert antimicrobial defence pathways using various mechanisms, including the targeting of host TLR-mediated transcriptional responses. Conversely, TLR-inducible host defence mechanisms subject intramacrophage pathogens to stress, thus altering pathogen gene expression programs. Important biological insights can thus be gained through the analysis of gene expression changes in both the host and the pathogen during an infection. Traditionally, research methods have involved the use of qPCR, microarrays and/or RNA sequencing to identify transcriptional changes in either the host or the pathogen. Here we describe the application of RNA sequencing using samples obtained from in vitro infection assays to simultaneously quantify both host and bacterial pathogen gene expression changes, as well as general approaches that can be undertaken to interpret the RNA sequencing data that is generated. These methods can be used to provide insights into host TLR-regulated transcriptional responses to microbial challenge, as well as pathogen subversion mechanisms against such responses.

  12. Treatment of catheter-related bacteraemia with an antibiotic lock protocol: effect of bacterial pathogen.

    Science.gov (United States)

    Poole, Christopher V; Carlton, Donna; Bimbo, Lisa; Allon, Michael

    2004-05-01

    The standard therapy of dialysis catheter-related bacteraemia involves both systemic antibiotics and catheter replacement. We reported recently that instillation of an antibiotic lock (highly concentrated antibiotic solution) into the catheter lumen after dialysis sessions, in conjunction with systemic antibiotics, can successfully treat many episodes of catheter-related bacteraemia without requiring catheter removal. The present study evaluated whether the likelihood of achieving a cure with this protocol depends on the type of pathogen. This was a historically controlled interventional study of an antibiotic lock protocol for the treatment of catheter-related bacteraemia. We analysed prospectively the likelihood of clinical cure (fever resolution and negative surveillance cultures) with an antibiotic lock protocol among patients with dialysis catheter-related bacteraemia. In addition, infection-free catheter survival was evaluated for up to 150 days, and compared with that observed among patients managed with routine catheter replacement. Overall, the antibiotic lock protocol was successful in 33 of 47 infected patients (70%) with catheter-related bacteraemia. The likelihood of a clinical cure was 87% for Gram-negative infections, 75% for Staphylococcus epidermidis infections, and only 40% for Staphylococcus aureus infections (P = 0.04). The median infection-free catheter survival with the antibiotic lock protocol was longer than that observed among patients with routine catheter replacement (154 vs 71 days, P = 0.02). The clinical success of an antibiotic lock protocol in eradicating catheter-related bacteraemia while salvaging the catheter is highly dependent on the bacterial pathogen. Thus, the overall success rate in an individual dialysis programme will depend on the relative frequencies of different bacterial pathogens.

  13. Metabolic pathways of Pseudomonas aeruginosa involved in competition with respiratory bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Marie eBeaume

    2015-04-01

    Full Text Available Background: Chronic airway infection by Pseudomonas aeruginosa considerably contributes to lung tissue destruction and impairment of pulmonary function in cystic-fibrosis (CF patients. Complex interplays between P. aeruginosa and other co-colonizing pathogens including Staphylococcus aureus, Burkholderia spp and Klebsiella pneumoniae may be crucial for pathogenesis and disease progression.Methods: We generated a library of PA14 transposon insertion mutants to identify P. aeruginosa genes required for exploitative and direct competitions with S. aureus, B. cenocepacia, and K. pneumoniae. Results: Whereas wild type PA14 inhibited S. aureus growth, two transposon insertions located in pqsC and carB, resulted in reduced growth inhibition. PqsC is involved in the synthesis of 4-hydroxy-2-alkylquinolines (HAQs, a family of molecules having antibacterial properties, while carB is a key gene in pyrimidine biosynthesis. The carB mutant was also unable to grow in the presence of B. cepacia and K. pneumoniae but not E. coli and S. epidermidis. We further identified a transposon insertion in purF, encoding a key enzyme of purine metabolism. This mutant displayed a severe growth deficiency in the presence of Gram-negative but not of Gram-positive bacteria. We identified a beneficial interaction in a bioA transposon mutant, unable to grow on rich medium. This growth defect could be restored either by addition of biotin or by co-culturing the mutant in the presence of K. pneumoniae or E. coli.Conclusions: Complex interactions take place between the various bacterial species colonizing CF-lungs. This work identified both detrimental and beneficial interactions occurring between P. aeruginosa and three other respiratory pathogens involving several major metabolic pathways. Manipulating these pathways could be used to interfere with bacterial interactions and influence the colonization by respiratory pathogens.

  14. Cockroaches as a Source of High Bacterial Pathogens with Multidrug Resistant Strains in Gondar Town, Ethiopia.

    Science.gov (United States)

    Moges, Feleke; Eshetie, Setegn; Endris, Mengistu; Huruy, Kahsay; Muluye, Dagnachew; Feleke, Tigist; G/Silassie, Fisha; Ayalew, Getenet; Nagappan, Raja

    2016-01-01

    Background. Cockroaches are source of bacterial infections and this study was aimed to assess bacterial isolates and their antimicrobial profiles from cockroaches in Gondar town, Ethiopia. Methods. A total of 60 cockroaches were collected from March 1 to May 30, 2014, in Gondar town. Bacterial species were isolated from external and internal parts of cockroaches. Disk diffusion method was used to determine antibiotic susceptibility patterns. Data were entered and analyzed by using SPSS version 20; P values cockroaches, respectively. Klebsiella pneumoniae 32 (17.7%), Escherichia coli 29 (16%), and Citrobacter spp. 27 (15%) were the predominant isolates. High resistance rate was observed to cotrimoxazole, 60 (33.1%), and least resistance rate was noted to ciprofloxacin, 2 (1.1%). Additionally, 116 (64.1%) of the isolates were MDR strains; Salmonella spp. were the leading MDR isolates (100%) followed by Enterobacter (90.5%) and Shigella spp. (76.9%). Conclusion. Cockroaches are the potential source of bacteria pathogens with multidrug resistant strains and hence effective preventive and control measures are required to minimize cockroach related infections.

  15. A novel bacterial pathogen of Biomphalaria glabrata: a potential weapon for schistosomiasis control?

    Science.gov (United States)

    Duval, David; Galinier, Richard; Mouahid, Gabriel; Toulza, Eve; Allienne, Jean François; Portela, Julien; Calvayrac, Christophe; Rognon, Anne; Arancibia, Nathalie; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

    2015-02-01

    Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects. In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs. This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field.

  16. A novel bacterial pathogen of Biomphalaria glabrata: a potential weapon for schistosomiasis control?

    Directory of Open Access Journals (Sweden)

    David Duval

    2015-02-01

    Full Text Available Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects.In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs.This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field.

  17. A human pathogenic bacterial infection model using the two-spotted cricket, Gryllus bimaculatus.

    Science.gov (United States)

    Kochi, Yuto; Miyashita, Atsushi; Tsuchiya, Kohsuke; Mitsuyama, Masao; Sekimizu, Kazuhisa; Kaito, Chikara

    2016-08-01

    Invertebrate animal species that can withstand temperatures as high as 37°C, the human body temperature, are limited. In the present study, we utilized the two-spotted cricket, Gryllus bimaculatus, which lives in tropical and subtropical regions, as an animal model of human pathogenic bacterial infection. Injection of Pseudomonas aeruginosa or Staphylococcus aureus into the hemolymph killed crickets. Injected P. aeruginosa or S. aureus proliferated in the hemolymph until the cricket died. The ability of these pathogenic bacteria to kill the crickets was blocked by the administration of antibiotics. S. aureus gene-knockout mutants of virulence factors, including cvfA, agr and srtA, exhibited decreased killing ability compared with the parent strain. The dose at which 50% of crickets were killed by P. aeruginosa or S. aureus was not decreased at 37°C compared with that at 27°C. Injection of Listeria monocytogenes, which upregulates toxin expression at 37°C, killed crickets, and the dose at which 50% of crickets were killed was decreased at 37°C compared with that at 27°C. These findings suggest that the two-spotted cricket is a useful model animal for evaluating the virulence properties of various human pathogenic bacteria at variable temperature including 37°C. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Transmission of Bacterial Zoonotic Pathogens between Pets and Humans: The Role of Pet Food.

    Science.gov (United States)

    Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Pradhan, Abani K

    2016-01-01

    Recent Salmonella outbreaks associated with dry pet food and treats raised the level of concern for these products as vehicle of pathogen exposure for both pets and their owners. The need to characterize the microbiological and risk profiles of this class of products is currently not supported by sufficient specific data. This systematic review summarizes existing data on the main variables needed to support an ingredients-to-consumer quantitative risk model to (1) describe the microbial ecology of bacterial pathogens in the dry pet food production chain, (2) estimate pet exposure to pathogens through dry food consumption, and (3) assess human exposure and illness incidence due to contact with pet food and pets in the household. Risk models populated with the data here summarized will provide a tool to quantitatively address the emerging public health concerns associated with pet food and the effectiveness of mitigation measures. Results of such models can provide a basis for improvements in production processes, risk communication to consumers, and regulatory action.

  19. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    Directory of Open Access Journals (Sweden)

    Leonardo De La Fuente

    Full Text Available Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen.

  20. The Bacterial Pathogen Xylella fastidiosa Affects the Leaf Ionome of Plant Hosts during Infection

    Science.gov (United States)

    De La Fuente, Leonardo; Parker, Jennifer K.; Oliver, Jonathan E.; Granger, Shea; Brannen, Phillip M.; van Santen, Edzard; Cobine, Paul A.

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

  1. First report of bacterial stem rot of ‘heirloom’ tomatoes caused by Pectobacterium carotovorum subsp. brasiliensis in Florida

    Science.gov (United States)

    In the spring of 2014, a field experiment was established to evaluate the growth of ‘heirloom’ tomato types in a vertical garden hydroponic system. During bloom, approximately 40% of the established plants of the variety ‘Black Prince’ were severely wilted with necrotic upper leaves. Stems of infe...

  2. Peptidomimetic Small Molecules Disrupt Type IV Secretion System Activity in Diverse Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Carrie L. Shaffer

    2016-04-01

    Full Text Available Bacteria utilize complex type IV secretion systems (T4SSs to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85 that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA and peptidoglycan into gastric epithelial cells. In H. pylori, KSK85 impedes biogenesis of the pilus appendage associated with the cag T4SS, while C10 disrupts cag T4SS activity without perturbing pilus assembly. In addition to the effects in H. pylori, we demonstrate that these compounds disrupt interbacterial DNA transfer by conjugative T4SSs in Escherichia coli and impede vir T4SS-mediated DNA delivery by Agrobacterium tumefaciens in a plant model of infection. Of note, C10 effectively disarmed dissemination of a derepressed IncF plasmid into a recipient bacterial population, thus demonstrating the potential of these compounds in mitigating the spread of antibiotic resistance determinants driven by conjugation. To our knowledge, this study is the first report of synthetic small molecules that impair delivery of both effector protein and DNA cargos by diverse T4SSs.

  3. Rapid identification of bacterial pathogens using a PCR- and microarray-based assay

    Directory of Open Access Journals (Sweden)

    Aittakorpi Anne

    2009-08-01

    Full Text Available Abstract Background During the course of a bacterial infection, the rapid identification of the causative agent(s is necessary for the determination of effective treatment options. We have developed a method based on a modified broad-range PCR and an oligonucleotide microarray for the simultaneous detection and identification of 12 bacterial pathogens at the species level. The broad-range PCR primer mixture was designed using conserved regions of the bacterial topoisomerase genes gyrB and parE. The primer design allowed the use of a novel DNA amplification method, which produced labeled, single-stranded DNA suitable for microarray hybridization. The probes on the microarray were designed from the alignments of species- or genus-specific variable regions of the gyrB and parE genes flanked by the primers. We included mecA-specific primers and probes in the same assay to indicate the presence of methicillin resistance in the bacterial species. The feasibility of this assay in routine diagnostic testing was evaluated using 146 blood culture positive and 40 blood culture negative samples. Results Comparison of our results with those of a conventional culture-based method revealed a sensitivity of 96% (initial sensitivity of 82% and specificity of 98%. Furthermore, only one cross-reaction was observed upon investigating 102 culture isolates from 70 untargeted bacteria. The total assay time was only three hours, including the time required for the DNA extraction, PCR and microarray steps in sequence. Conclusion The assay rapidly provides reliable data, which can guide optimal antimicrobial treatment decisions in a timely manner.

  4. Molecular viability testing of bacterial pathogens from a complex human sample matrix.

    Directory of Open Access Journals (Sweden)

    Kris M Weigel

    Full Text Available Assays for bacterial ribosomal RNA precursors (pre-rRNA have been shown to distinguish viable from inactivated bacterial cells in drinking water samples. Because the synthesis of pre-rRNA is rapidly induced by nutritional stimulation, viable bacteria can be distinguished from inactivated cells and free nucleic acids by measuring the production of species-specific pre-rRNA in samples that have been briefly stimulated with nutrients. Here, pre-rRNA analysis was applied to bacteria from serum, a human sample matrix. In contrast to drinking water, serum is rich in nutrients that might be expected to mask the effects of nutritional stimulation. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR assays were used to detect pre-rRNA of four bacterial species: Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, and the Mycobacterium tuberculosis complex. These species were chosen for their clinical significance and phylogenetic diversity (Proteobacteria, Firmicutes, and Actinobacteria. To maximize resolving power, pre-rRNA was normalized to genomic DNA of each pathogen. When viable cells were shifted from serum to bacteriological culture medium, rapid replenishment of pre-rRNA was always observed. Cells of P. aeruginosa that were inactivated in the presence of serum exhibited no pre-rRNA response to nutritional stimulation, despite strong genomic DNA signals in these samples. When semi-automated methods were used, pre-rRNA analysis detected viable A. baumannii cells in serum at densities of ≤100 CFU/mL in <5.5 hours. Originally developed for rapid microbiological analysis of drinking water, ratiometric pre-rRNA analysis can also assess the viability of bacterial cells derived from human specimens, without requiring bacteriological culture.

  5. Rhizosphere Microbiome Recruited from a Suppressive Compost Improves Plant Fitness and Increases Protection against Vascular Wilt Pathogens of Tomato

    NARCIS (Netherlands)

    Antoniou, Anastasis; Tsolakidou, Maria; Stringlis, I.; Pantelides, Iakovos

    2017-01-01

    Suppressive composts represent a sustainable approach to combat soilborne plant pathogens and an alternative to the ineffective chemical fungicides used against those. Nevertheless, suppressiveness to plant pathogens and reliability of composts are often inconsistent with unpredictable effects.

  6. Pathogenic triad in bacterial meningitis: pathogen invasion, NF-κB activation and leukocyte transmigration that occur at the Blood-Brain Barrier

    Directory of Open Access Journals (Sweden)

    Sheng-He eHuang

    2016-02-01

    Full Text Available Bacterial meningitis remains the leading cause of disabilities worldwide. This life-threatening disease has a high mortality rate despite the availability of antibiotics and improved critical care. The interactions between bacterial surface components and host defense systems that initiate bacterial meningitis have been studied in molecular and cellular detail over the past several decades. Bacterial meningitis commonly exhibits triad hallmark features (THFs: pathogen penetration, nuclear factor-kappaB (NF-B activation in coordination with type 1 interferon (IFN signaling and leukocyte transmigration that occur at the blood-brain barrier (BBB, which consists mainly of brain microvascular endothelial cells (BMEC. This review outlines the progression of these early inter-correlated events contributing to the central nervous system (CNS inflammation and injury during the pathogenesis of bacterial meningitis. A better understanding of these issues is not only imperative to elucidating the pathogenic mechanism of bacterial meningitis, but may also provide the in-depth insight into the development of novel therapeutic interventions against this disease.

  7. TALE-induced bHLH transcription factors that activate a pectate lyase contribute to water soaking in bacterial spot of tomato.

    Science.gov (United States)

    Schwartz, Allison R; Morbitzer, Robert; Lahaye, Thomas; Staskawicz, Brian J

    2017-01-31

    AvrHah1 [avirulence (avr) gene homologous to avrBs3 and hax2, no. 1] is a transcription activator-like (TAL) effector (TALE) in Xanthomonas gardneri that induces water-soaked disease lesions on fruits and leaves during bacterial spot of tomato. We observe that water from outside the leaf is drawn into the apoplast in X. gardneri-infected, but not X. gardneriΔavrHah1 (XgΔavrHah1)-infected, plants, conferring a dark, water-soaked appearance. The pull of water can facilitate entry of additional bacterial cells into the apoplast. Comparing the transcriptomes of tomato infected with X. gardneri vs. XgΔavrHah1 revealed the differential up-regulation of two basic helix-loop-helix (bHLH) transcription factors with predicted effector binding elements (EBEs) for AvrHah1. We mined our RNA-sequencing data for differentially up-regulated genes that could be direct targets of the bHLH transcription factors and therefore indirect targets of AvrHah1. We show that two pectin modification genes, a pectate lyase and pectinesterase, are targets of both bHLH transcription factors. Designer TALEs (dTALEs) for the bHLH transcription factors and the pectate lyase, but not for the pectinesterase, complement water soaking when delivered by XgΔavrHah1 By perturbing transcriptional networks and/or modifying the plant cell wall, AvrHah1 may promote water uptake to enhance tissue damage and eventual bacterial egression from the apoplast to the leaf surface. Understanding how disease symptoms develop may be a useful tool for improving the tolerance of crops from damaging disease lesions.

  8. 'Bioluminescent' reporter phage for the detection of Category A bacterial pathogens.

    Science.gov (United States)

    Schofield, David A; Molineux, Ian J; Westwater, Caroline

    2011-07-08

    Yersinia pestis and Bacillus anthracis are Category A bacterial pathogens that are the causative agents of the plague and anthrax, respectively. Although the natural occurrence of both diseases' is now relatively rare, the possibility of terrorist groups using these pathogens as a bioweapon is real. Because of the disease's inherent communicability, rapid clinical course, and high mortality rate, it is critical that an outbreak be detected quickly. Therefore methodologies that provide rapid detection and diagnosis are essential to ensure immediate implementation of public health measures and activation of crisis management. Recombinant reporter phage may provide a rapid and specific approach for the detection of Y. pestis and B. anthracis. The Centers for Disease Control and Prevention currently use the classical phage lysis assays for the confirmed identification of these bacterial pathogens. These assays take advantage of naturally occurring phage which are specific and lytic for their bacterial hosts. After overnight growth of the cultivated bacterium in the presence of the specific phage, the formation of plaques (bacterial lysis) provides a positive identification of the bacterial target. Although these assays are robust, they suffer from three shortcomings: 1) they are laboratory based; 2) they require bacterial isolation and cultivation from the suspected sample, and 3) they take 24-36 h to complete. To address these issues, recombinant "light-tagged" reporter phage were genetically engineered by integrating the Vibrio harveyi luxAB genes into the genome of Y. pestis and B. anthracis specific phage. The resulting luxAB reporter phage were able to detect their specific target by rapidly (within minutes) and sensitively conferring a bioluminescent phenotype to recipient cells. Importantly, detection was obtained either with cultivated recipient cells or with mock-infected clinical specimens. For demonstration purposes, here we describe the method for the phage

  9. Bacterial Seed Endophytes of Domesticated Cucurbits Antagonize Fungal and Oomycete Pathogens Including Powdery Mildew

    Directory of Open Access Journals (Sweden)

    Eman M. Khalaf

    2018-02-01

    Full Text Available The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits. We hypothesized that these endophytes can antagonize major fungal and oomycete pathogens. Here we tested the endophytes for in vitro antagonism (dual culture assays against important soil-borne pathogens (Rhizoctonia solani, Fusarium graminearum, Phytophthora capsici, Pythium aphanideratum. The endophytes were also assayed in planta (leaf disk and detached leaf bioassays for antagonism against a foliar pathogen of global importance, Podosphaera fuliginea, the causative agent of cucurbit powdery mildew. The endophytes were further tested in vitro for secretion of volatile organic compounds (VOCs known to induce plant defense. Extracellular ribonuclease activity was also tested, as a subset of pathogenesis-related (PR proteins of plant hosts implicated in suppression of fungal pathogens, displays ribonuclease activity. An unexpected majority of the endophytes (70%, 118/169 exhibited antagonism to the five phytopathogens, of which 68% (50/73 of in vitro antagonists belong to the genera Bacillus and Paenibacillus. All Lactococcus and Pantoea endophytes exhibited anti-oomycete activity. However, amongst the most effective inoculants against Podosphaera fuliginea were Pediococcus and Pantoea endophytes. Interestingly, 67% (113/169 of endophytes emitted host defense inducing VOCs (acetoin/diacetyl and 62% (104/169 secreted extracellular ribonucleases in vitro, respectively. These results show that seeds of cultivated

  10. Effeciency of fungal and bacterial biocontrol organisms for the ...

    African Journals Online (AJOL)

    Fungal and bacterial biocontrol organisms with known activity against soil borne fungal pathogens were tested for their efficacy in controlling Fusarium wilt of tomato in the screen house. The trial tested five organisms (Trichoderma virile, Trichoderma harzianum, Penicillium oxalicum, Bacilius subtilis and Pseudomonas ...

  11. Real-time qPCR improves meningitis pathogen detection in invasive bacterial-vaccine preventable disease surveillance in Fiji

    OpenAIRE

    Dunne, Eileen M.; Mantanitobua, Silivia; Singh, Shalini P.; Reyburn, Rita; Tuivaga, Evelyn; Rafai, Eric; Tikoduadua, Lisi; Porter, Barbara; Satzke, Catherine; Strachan, Janet E.; Fox, Kimberly K.; Jenkins, Kylie M.; Jenney, Adam; Baro, Silo; Mulholland, E. Kim

    2016-01-01

    As part of the World Health Organization Invasive Bacterial-Vaccine Preventable Diseases (IB-VPD) surveillance in Suva, Fiji, cerebrospinal fluid (CSF) samples from suspected meningitis patients of all ages were examined by traditional methods (culture, Gram stain, and latex agglutination for bacterial antigen) and qPCR for Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. Of 266 samples tested, pathogens were identified in 47 (17.7%). S. pneumoniae was the most co...

  12. Gold Nanoparticles: An Efficient Antimicrobial Agent against Enteric Bacterial Human Pathogen

    Directory of Open Access Journals (Sweden)

    Shahzadi Shamaila

    2016-04-01

    Full Text Available Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent. Ultra Violet (UV-visible spectroscopy revealed the size of chemically synthesized gold nanoparticle as 6–40 nm. Atomic force microscopy (AFM analysis confirmed the size and X-ray diffractometry (XRD analysis determined the polycrystalline nature of gold nanoparticles. The present findings explained how gold nanoparticles lyse Gram-negative and Gram-positive bacteria.

  13. A Review of Phage Therapy against Bacterial Pathogens of Aquatic and Terrestrial Organisms

    Directory of Open Access Journals (Sweden)

    Janis Doss

    2017-03-01

    Full Text Available Since the discovery of bacteriophage in the early 1900s, there have been numerous attempts to exploit their innate ability to kill bacteria. The purpose of this report is to review current findings and new developments in phage therapy with an emphasis on bacterial diseases of marine organisms, humans, and plants. The body of evidence includes data from studies investigating bacteriophage in marine and land environments as modern antimicrobial agents against harmful bacteria. The goal of this paper is to present an overview of the topic of phage therapy, the use of phage-derived protein therapy, and the hosts that bacteriophage are currently being used against, with an emphasis on the uses of bacteriophage against marine, human, animal and plant pathogens.

  14. DNA replication proteins as potential targets for antimicrobials in drug-resistant bacterial pathogens.

    Science.gov (United States)

    van Eijk, Erika; Wittekoek, Bert; Kuijper, Ed J; Smits, Wiep Klaas

    2017-05-01

    With the impending crisis of antimicrobial resistance, there is an urgent need to develop novel antimicrobials to combat difficult infections and MDR pathogenic microorganisms. DNA replication is essential for cell viability and is therefore an attractive target for antimicrobials. Although several antimicrobials targeting DNA replication proteins have been developed to date, gyrase/topoisomerase inhibitors are the only class widely used in the clinic. Given the numerous essential proteins in the bacterial replisome that may serve as a potential target for inhibitors and the relative paucity of suitable compounds, it is evident that antimicrobials targeting the replisome are underdeveloped so far. In this review, we report on the diversity of antimicrobial compounds targeting DNA replication and highlight some of the challenges in developing new drugs that target this process. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

  15. Molecular characterization of Pseudomonas syringae pv. tomato isolates from Tanzania

    DEFF Research Database (Denmark)

    Shenge, K.C.; Stephan, D.; Mabagala, R. B.

    2008-01-01

    Bacterial speck caused by Pseudomonas syringae pv. tomato is an emerging disease of tomato in Tanzania. Following reports of outbreaks of the disease in many locations in Tanzania, 56 isolates of P. syringae pv. tomato were collected from four tomato- producing areas and characterized using patho...

  16. Bacterial pathogen emergence required more than direct contact with a novel passerine host.

    Science.gov (United States)

    Staley, Molly; Hill, Geoffrey E; Josefson, Chloe C; Armbruster, Jonathan W; Bonneaud, Camille

    2018-01-08

    While direct contact may sometimes be sufficient to allow a pathogen to jump into a new host species, in other cases fortuitously adaptive mutations that arise in the original donor host are also necessary. Viruses have been the focus of most host shift studies, so less is known about the importance of ecological versus evolutionary processes to successful bacterial host shifts. Here we tested whether direct contact with the novel host was sufficient to enable the mid-1990s jump of the bacterium Mycoplasma gallisepticum from domestic poultry into house finches ( Haemorhous mexicanus ). We experimentally inoculated house finches with two genetically distinct M. gallisepticum strains obtained either from poultry (Rlow) or from house finches at epizootic outbreak (HF1995). All 15 house finches inoculated with HF1995 became infected, whereas Rlow successfully infected 12 of 15 (80%) inoculated house finches. Comparisons among infected birds showed that, relative to HF1995, Rlow achieved substantially lower bacterial loads in the host respiratory mucosa and was cleared faster. Furthermore, Rlow-infected finches were less likely to develop clinical symptoms than HF1995-infected birds and, when they did, displayed milder conjunctivitis. The lower infection success of Rlow relative to HF1995 was not, however, due to a heightened host antibody response to Rlow. Taken together, our results indicate that contact between infected poultry and house finches was not, by itself, sufficient to explain the jump of M. gallisepticum into house finches. Instead, mutations arising in the original poultry host would have been necessary for successful pathogen emergence in the novel finch host. Copyright © 2018 Staley et al.

  17. Effects of tomato variety, temperature differential and post-stem removal time on internalization of Salmonella Thompson into tomatoes

    Science.gov (United States)

    Tomatoes have been implicated in several Salmonellosis outbreaks due to possible contamination through bacterial infiltration into tomatoes during post-harvest handling. The aim of this study was to determine the effects of tomato variety, dump tank water to tomato pulp temperature differential, and...

  18. Clinical Epidemiology of Septic Arthritis Caused byBurkholderia pseudomalleiand Other Bacterial Pathogens in Northeast Thailand.

    Science.gov (United States)

    Teparrukkul, Prapit; Nilsakul, Jiraphorn; Dunachie, Susanna; Limmathurotsakul, Direk

    2017-12-01

    Septic arthritis is a medical emergency, and if not treated appropriately, it can be associated with high morbidity and mortality. Melioidosis, a serious infectious disease caused by the Gram-negative bacillus Burkholderia pseudomallei , is highly endemic in South and Southeast Asia and northern Australia. We reviewed the medical charts of adult patients admitted with bacterial septic arthritis at Sunpasitthiprasong Hospital, Ubon Ratchathani, northeast Thailand from January 2012 to December 2014. Bacterial septic arthritis was defined as one or more hot swollen joints with isolation of a pathogenic organism from an affected joint or from blood. A total of 154 patients with septic arthritis were retrospectively evaluated. The most common causes were B. pseudomallei (48%, N = 74), Streptococcus spp. (29%, N = 44), and Staphylococcus aureus (10%, N = 16). Prevalence of diabetes, bacteremia, and pneumonia was higher in B. pseudomallei septic arthritis than in septic arthritis caused by the other bacteria (all P septic arthritis is common and associated with high mortality in northeast Thailand. Emergence of Streptococcus arthritis is observed. Difficulty in diagnosing melioidosis and identifying B. pseudomallei in areas where health care workers are not familiar with the disease is discussed. In melioidosis-endemic regions, parenteral ceftazidime could be considered as empirical antimicrobial therapy for patients with septic arthritis and underlying diseases.

  19. Transcriptional responses of resistant and susceptible fish clones to the bacterial pathogen Flavobacterium psychrophilum.

    Directory of Open Access Journals (Sweden)

    Christelle Langevin

    Full Text Available Flavobacterium psychrophilum is a bacterial species that represents one of the most important pathogens for aquaculture worldwide, especially for salmonids. To gain insights into the genetic basis of the natural resistance to F. psychrophilum, we selected homozygous clones of rainbow trout with contrasted susceptibility to the infection. We compared the transcriptional response to the bacteria in the pronephros of a susceptible and a resistant line by micro-array analysis five days after infection. While the basal transcriptome of healthy fish was significantly different in the resistant and susceptible lines, the transcriptome modifications induced by the bacteria involved essentially the same genes and pathways. The response to F. psychrophilum involved antimicrobial peptides, complement, and a number of enzymes and chemokines. The matrix metalloproteases mmp9 and mmp13 were among the most highly induced genes in both genetic backgrounds. Key genes of both pro- and anti-inflammatory response such as IL1 and IL10, were up-regulated with a greater magnitude in susceptible animals where the bacterial load was also much higher. While higher resistance to F. psychrophilum does not seem to be based on extensive differences in the orientation of the immune response, several genes including complement C3 showed stronger induction in the resistant fish. They may be important for the variation of susceptibility to the infection.

  20. Hyperglycemia Impairs Neutrophil-Mediated Bacterial Clearance in Mice Infected with the Lyme Disease Pathogen.

    Directory of Open Access Journals (Sweden)

    Ashkan Javid

    Full Text Available Insulin-insufficient type 1 diabetes is associated with attenuated bactericidal function of neutrophils, which are key mediators of innate immune responses to microbes as well as pathological inflammatory processes. Neutrophils are central to immune responses to the Lyme pathogen Borrelia burgdorferi. The effect of hyperglycemia on host susceptibility to and outcomes of B. burgdorferi infection has not been examined. The present study investigated the impact of sustained obesity-independent hyperglycemia in mice on bacterial clearance, inflammatory pathology and neutrophil responses to B. burgdorferi. Hyperglycemia was associated with reduced arthritis incidence but more widespread tissue colonization and reduced clearance of bacterial DNA in multiple tissues including brain, heart, liver, lung and knee joint. B. burgdorferi uptake and killing were impaired in neutrophils isolated from hyperglycemic mice. Thus, attenuated neutrophil function in insulin-insufficient hyperglycemia was associated with reduced B. burgdorferi clearance in target organs. These data suggest that investigating the effects of comorbid conditions such as diabetes on outcomes of B. burgdorferi infections in humans may be warranted.

  1. Molecular genetic anatomy of inter- and intraserotype variation in the human bacterial pathogen group A Streptococcus.

    Science.gov (United States)

    Beres, Stephen B; Richter, Ellen W; Nagiec, Michal J; Sumby, Paul; Porcella, Stephen F; DeLeo, Frank R; Musser, James M

    2006-05-02

    In recent years we have studied the relationship between strain genotypes and patient phenotypes in group A Streptococcus (GAS), a model human bacterial pathogen that causes extensive morbidity and mortality worldwide. We have concentrated our efforts on serotype M3 organisms because these strains are common causes of pharyngeal and invasive infections, produce unusually severe invasive infections, and can exhibit epidemic behavior. Our studies have been hindered by the lack of genome-scale phylogenies of multiple GAS strains and whole-genome sequences of multiple serotype M3 strains recovered from individuals with defined clinical phenotypes. To remove some of these impediments, we sequenced to closure the genome of four additional GAS strains and conducted comparative genomic resequencing of 12 contemporary serotype M3 strains representing distinct genotypes and phenotypes. Serotype M3 strains are a single phylogenetic lineage. Strains from asymptomatic throat carriers were significantly less virulent for mice than sterile-site isolates and evolved to a less virulent phenotype by multiple genetic pathways. Strain persistence or extinction between epidemics was strongly associated with presence or absence, respectively, of the prophage encoding streptococcal pyrogenic exotoxin A. A serotype M3 clone significantly underrepresented among necrotizing fasciitis cases has a unique frameshift mutation that truncates MtsR, a transcriptional regulator controlling expression of genes encoding iron-acquisition proteins. Expression microarray analysis of this clone confirmed significant alteration in expression of genes encoding iron metabolism proteins. Our analysis provided unprecedented detail about the molecular anatomy of bacterial strain genotype-patient phenotype relationships.

  2. The bioactivity of plant extracts against representative bacterial pathogens of the lower respiratory tract.

    Science.gov (United States)

    Bocanegra-García, Virgilio; Del Rayo Camacho-Corona, María; Ramírez-Cabrera, Mónica; Rivera, Gildardo; Garza-González, Elvira

    2009-06-01

    Lower respiratory tract infections are a major cause of illness and death. Such infections are common in intensive care units (ICU) and their lethality persists despite advances in diagnosis, treatment and prevention. In Mexico, some plants are used in traditional medicine to treat respiratory diseases or ailments such as cough, bronchitis, tuberculosis and other infections. Medical knowledge derived from traditional societies has motivated searches for new bioactive molecules derived from plants that show potent activity against bacterial pathogens. Therefore, the aim of this study was to evaluate the effect of hexanic, chloroformic (CLO), methanolic (MET) and aqueous extracts from various plants used in Mexican traditional medicine on various microorganisms associated with respiratory disease. thirty-five extracts prepared from nine plants used in Mexican traditional medicine for the treatment of respiratory infections were evaluated against 15 control bacterial species and clinical isolates. Both chloroformic (CLO) and methanolic (MET) extracts of Larrea tridentata were active against Methicillin-resistant S. aureus, B. subtilis and L. monocytogenes. A MET extract of L. tridentata was also active against S. aureus, S. pneumoniae, S. maltophilia, E. faecalis and H. influenzae and the CLO extract was active against A. baumannii. An Aqueous extract of M. acumitata and a MET extract of N. officinale were active against S. pneumoniae. CLO and MET extracts of L. tridentata were active against clinical isolates of S. aureus, S. pneumoniae and E. faecalis. Overall, our results support the potential use of L. tridentata as a source of antibacterial compounds.

  3. Functional properties of peanut fractions on the growth of probiotics and foodborne bacterial pathogens.

    Science.gov (United States)

    Peng, Mengfei; Bitsko, Elizabeth; Biswas, Debabrata

    2015-03-01

    Various compounds found in peanut (Arachis hypogaea) have been shown to provide multiple benefits to human health and may influence the growth of a broad range of gut bacteria. In this study, we investigated the effects of peanut white kernel and peanut skin on 3 strains of Lactobacillus and 3 major foodborne enteric bacterial pathogens. Significant (P growth stimulation of Lactobacillus casei and Lactobacillus rhamnosus was observed in the presence of 0.5% peanut flour (PF) made from peanut white kernel, whereas 0.5% peanut skin extract (PSE) exerted the inhibitory effect on the growth of these beneficial microbes. We also found that within 72 h, PF inhibited growth of enterohemorrhagic Escherichia coli O157:H7 (EHEC), while PSE significantly (P growth of both EHEC and Salmonella Typhimurium. The cell adhesion and invasion abilities of 3 pathogens to the host cells were also significantly (P < 0.05) reduced by 0.5% PF and 0.5% PSE. These results suggest that peanut white kernel might assist in improving human gut flora as well as reducing EHEC, whereas the beneficial effects of peanut skins require further research and investigation. © 2015 Institute of Food Technologists®

  4. Inhibition of beta-carbonic anhydrases from the bacterial pathogen Brucella suis with inorganic anions.

    Science.gov (United States)

    Maresca, Alfonso; Scozzafava, Andrea; Köhler, Stephan; Winum, Jean-Yves; Supuran, Claudiu T

    2012-05-01

    The bacterial pathogen Brucella suis encodes two carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the β-class, bsCA1 and bsCA2, which are crucial for its life cycle. Sulfonamides, strong inhibitors of these enzymes, were shown to block the growth of the pathogen in vitro. Here we report the inhibition of these two CAs by inorganic and complex anions and other molecules interacting with zinc proteins, such as sulfamide, sulfamic acid, and phenylboronic/arsonic acids. The enzyme bsCA1 was inhibited in the low micromolar range by sulfamide, sulfamic acid, phenylboronic/arsonic acid, and in the submillimolar range by diethyldithiocarbamate. Isoform bsCA2 generally showed a stronger inhibition with most of these anions, with several low micromolar and many submillimolar inhibitors detected. Micromolar inhibition against bsCA2 was observed for sulfamide and sulfamic acid, whereas diethyldithiocarbamate, perruthenate, pyrovanadate, tellurate and phenylarsonic acid showed inhibition constants in the range of 0.29-1.52mM. These inhibitors may be used as leads for developing anti-Brucella agents with a diverse mechanism of action compared to clinically used antibiotics. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Viral and bacterial pathogens identification in children hospitalised for severe pneumonia and parapneumonic empyema

    Directory of Open Access Journals (Sweden)

    Jean-Noël Telles

    2012-12-01

    Full Text Available Pneumonia is caused by respiratory bacteria and/or viruses. Little is known if co-infections are an aggravating factor in hospitalised children with severe pneumonia. We studied the impact of respiratory pathogens on the severity of pneumonia. Between 2007 and 2009, 52 children hospitalised with a well-documented diagnosis of communityacquired pneumonia (CAP, with or without parapneumonic empyema (PPE, were enrolled in the study. The patients were classified into 2 groups: CAP + PPE (n = 28 and CAP (n = 24. The identification of respiratory viruses and bacteria in nasopharyngeal aspirates and pleural effusion samples were performed using conventional bacterial techniques and molecular assays. Using real-time multiplex PCR and antigen detection, Streptococcus pneumoniae was the main agent identified in 76% of the cases by molecular tests and BinaxNOW® in pleural fluid. A total of 8% of pleural fluid samples remained undiagnosed. In nasopharyngeal aspirates, rhinovirus, parainfluenza viruses, human metapneumovirus, and respiratory syncytial virus were detected in both CAP and CAP + PPE populations; however, the percentage of viral co-detection was significantly higher in nasopharyngeal aspirates from CAP + PPE patients (35% compared with CAP patients (5%. In conclusion, viral co-detection was observed mainly in patients with more severe pneumonia. Molecular biology assays improved the pathogens detection in pneumonia and confirmed the S. pneumoniae detection by BinaxNOW® in pleural effusion samples. Interestingly, the main S. pneumoniae serotypes found in PPE are not the ones targeted by the heptavalent pneumococcal conjugate vaccine.

  6. Viral and bacterial pathogens identification in children hospitalised for severe pneumonia and parapneumonic empyema

    Directory of Open Access Journals (Sweden)

    Jean-Noël Telles

    2012-05-01

    Full Text Available Pneumonia is caused by respiratory bacteria and/or viruses. Little is known if co-infections are an aggravating factor in hospitalised children with severe pneumonia. We studied the impact of respiratory pathogens on the severity of pneumonia. Between 2007 and 2009, 52 children hospitalised with a well-documented diagnosis of communityacquired pneumonia (CAP, with or without parapneumonic empyema (PPE, were enrolled in the study. The patients were classified into 2 groups: CAP + PPE (n = 28 and CAP (n = 24. The identification of respiratory viruses and bacteria in nasopharyngeal aspirates and pleural effusion samples were performed using conventional bacterial techniques and molecular assays. Using real-time multiplex PCR and antigen detection, Streptococcus pneumoniae was the main agent identified in 76% of the cases by molecular tests and BinaxNOW® in pleural fluid. A total of 8% of pleural fluid samples remained undiagnosed. In nasopharyngeal aspirates, rhinovirus, parainfluenza viruses, human metapneumovirus, and respiratory syncytial virus were detected in both CAP and CAP + PPE populations; however, the percentage of viral co-detection was significantly higher in nasopharyngeal aspirates from CAP + PPE patients (35% compared with CAP patients (5%. In conclusion, viral co-detection was observed mainly in patients with more severe pneumonia. Molecular biology assays improved the pathogens detection in pneumonia and confirmed the S. pneumoniae detection by BinaxNOW® in pleural effusion samples. Interestingly, the main S. pneumoniae serotypes found in PPE are not the ones targeted by the heptavalent pneumococcal conjugate vaccine.

  7. Antibiotic Resistance Pattern of Bacterial Pathogens Isolated from Cow Dung Used to Fertilize Nigerian Fish Ponds

    Directory of Open Access Journals (Sweden)

    Funso S. OMOJOWO

    2013-02-01

    Full Text Available This study was carried out to isolate and identify antibiotic resistant bacteria from cow dung used for pond fertilization. Cow dung from over 200 cows in NIFFR integrated farms, New-Bussa, Nigeria were collected. Six bacterial pathogens; Escherichia coli, E. coli O157:H7, Shigella dysentariae, Staphylococcus aureus, Salmonella typhi, and Aeromonas hydrophila were isolated. Antibiotic susceptibility testing by the disk diffusion method was conducted using ofloxacin, amoxicillin, tetracycline, ampicillin, erythromycin, gentamicin, nalidixic acid and chloramphenicol. All the isolated organisms were 100% sensitive to ofloxacin. The multiple resistance patterns revealed that 100% were resistant to tetracycline, ampicillin (85.6%, amoxicillin (83.3%, chloramphenicol (66%, gentamicin (47.6%, erythromycin (44.4% and nalidixic acid (18.3%. The Public Health risks posed by the cow dung manure include proliferation of ponds with these organisms that are pathogenic to fish and man, contamination of the environment and the possible retention of these organisms in the table size fish.

  8. Selenazolinium Salts as “Small Molecule Catalysts” with High Potency against ESKAPE Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Karolina Witek

    2017-12-01

    Full Text Available In view of the pressing need to identify new antibacterial agents able to combat multidrug-resistant bacteria, we investigated a series of fused selenazolinium derivatives (1–8 regarding their in vitro antimicrobial activities against 25 ESKAPE-pathogen strains. Ebselen was used as reference compound. Most of the selenocompounds demonstrated an excellent in vitro activity against all S. aureus strains, with activities comparable to or even exceeding the one of ebselen. In contrast to ebselen, some selenazolinium derivatives (1, 3, and 7 even displayed significant actions against all Gram-negative pathogens tested. The 3-bromo-2-(1-hydroxy-1-methylethyl[1,2]selenazolo[2,3-a]pyridinium chloride (1 was particularly active (minimum inhibitory concentrations, MICs: 0.31–1.24 µg/mL for MRSA, and 0.31–2.48 µg/mL for Gram-negative bacteria and devoid of any significant mutagenicity in the Ames assay. Our preliminary mechanistic studies in cell culture indicated that their mode of action is likely to be associated with an alteration of intracellular levels of glutathione and cysteine thiols of different proteins in the bacterial cells, hence supporting the idea that such compounds interact with the intracellular thiolstat. This alteration of pivotal cysteine residues is most likely the result of a direct or catalytic oxidative modification of such residues by the highly reactive selenium species (RSeS employed.

  9. The many forms of a pleomorphic bacterial pathogen – The developmental network of Legionella pneumophila

    Directory of Open Access Journals (Sweden)

    Peter eRobertson

    2014-12-01

    Full Text Available Legionella pneumophila is a natural intracellular bacterial parasite of free-living freshwater protozoa and an accidental human pathogen that causes Legionnaires’ disease. L. pneumophila differentiates, and does it in style. Recent experimental data on L. pneumophila’s differentiation point at the existence of a complex network that involves many developmental forms. We intend readers to: (i understand the biological relevance of L. pneumophila’s forms found in freshwater and their potential to transmit Legionnaires’ disease, and (ii learn that the common depiction of L. pneumophila’s differentiation as a biphasic developmental cycle that alternates between a replicative and a transmissive form is but an oversimplification of the actual process. Our specific objectives are to provide updates on the molecular factors that regulate L. pneumophila’s differentiation (section 2, and describe the developmental network of L. pneumophila (section 3, which for clarity’s sake we have dissected into five separate developmental cycles. Finally, since each developmental form seems to contribute differently to the human pathogenic process and the transmission of Legionnaires’ disease, readers are presented with a challenge to develop novel methods to detect the various L. pneumophila forms present in water (section 4, as a means to improve our assessment of risk and more effectively prevent legionellosis outbreaks.

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

    Directory of Open Access Journals (Sweden)

    Lorraine P. Smith

    2011-01-01

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

  11. Complete Genome Sequence and Immunoproteomic Analyses of the Bacterial Fish Pathogen Streptococcus parauberis▿†

    Science.gov (United States)

    Nho, Seong Won; Hikima, Jun-ichi; Cha, In Seok; Park, Seong Bin; Jang, Ho Bin; del Castillo, Carmelo S.; Kondo, Hidehiro; Hirono, Ikuo; Aoki, Takashi; Jung, Tae Sung

    2011-01-01

    Although Streptococcus parauberis is known as a bacterial pathogen associated with bovine udder mastitis, it has recently become one of the major causative agents of olive flounder (Paralichthys olivaceus) streptococcosis in northeast Asia, causing massive mortality resulting in severe economic losses. S. parauberis contains two serotypes, and it is likely that capsular polysaccharide antigens serve to differentiate the serotypes. In the present study, the complete genome sequence of S. parauberis (serotype I) was determined using the GS-FLX system to investigate its phylogeny, virulence factors, and antigenic proteins. S. parauberis possesses a single chromosome of 2,143,887 bp containing 1,868 predicted coding sequences (CDSs), with an average GC content of 35.6%. Whole-genome dot plot analysis and phylogenetic analysis of a 60-kDa chaperonin-encoding gene and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-encoding gene showed that the strain was evolutionarily closely related to Streptococcus uberis. S. parauberis antigenic proteins were analyzed using an immunoproteomic technique. Twenty-one antigenic protein spots were identified in S. parauberis, by reaction with an antiserum obtained from S. parauberis-challenged olive flounder. This work provides the foundation needed to understand more clearly the relationship between pathogen and host and develops new approaches toward prophylactic and therapeutic strategies to deal with streptococcosis in fish. The work also provides a better understanding of the physiology and evolution of a significant representative of the Streptococcaceae. PMID:21531805

  12. Antibiotic resistance and virulence traits of bacterial pathogens from infected freshwater fish, Labeo rohita.

    Science.gov (United States)

    Ramesh, Dharmaraj; Souissi, Sami

    2018-03-01

    Bacterial infectious diseases are a main dangerous problem in Aquaculture farming. It causes multiple diseases in fish as well as in human being and it has considerable virulence potential. In this connection, the moot of study focus to discriminate bacterial isolates recovered from naturally diseased Labeo rohita fish and their virulent characteristics. Based on the β-haemolysis factor, four isolates (KADR11, KADR12, KADR13 and KADR14) were selected for further delineation. These bacterial isolates showed high similarity with Providencia rettgeri, Aeromonas sp., Aeromonas sp. and Aeromonas enteropelogenes respectively, using partial 16S r-RNA gene amplification and biochemical characterizations were also supported. The further study investigates the virulence characteristics of isolates showed separation of outer membrane proteins (OMPs) and lipopolysaccharides (LPS) which appeared between 19 _ 80 kDa and 20 _ 100 kDa in SDS _ PAGE analysis respectively. All the four strains were complete resistant (100%) to β-lactam antibiotics. L. rohita were injected intraperitoneally with 0 (control), 2.0 × 10 4 , 2.0 × 10 5 , 2.0 × 10 6 , 2.0 × 10 7 and 2.0 × 10 8  cells/fish of Providencia rettgeri KADR11, Aeromonas sp. KADR12, Aeromonas sp. KADR13 and Aeromonas enteropelogenes KADR14 for the determination of lethal dose 50 (LD 50 ) values, which were 2.4 × 10 7 , 4.1 × 10 5 , 2.7 × 10 7 and 7.4 × 10 5  cells/fish respectively. The results indicated that isolated strains were possessed the high pathogenic potential for L. rohita. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Bacterial rRNA-Targeted Reverse Transcription-PCR Used To Identify Pathogens Responsible for Fever with Neutropenia▿

    OpenAIRE

    Sakaguchi, Sachi; Saito, Masahiro; Tsuji, Hirokazu; Asahara, Takashi; Takata, Oto; Fujimura, Junya; Nagata, Satoru; Nomoto, Koji; Shimizu, Toshiaki

    2010-01-01

    The purpose of this study was to evaluate the clinical utility of bacterial rRNA-targeted reverse transcription-quantitative PCR (BrRNA RT-qPCR) assays for identifying the bacterial pathogens that cause fever with neutropenia in pediatric cancer patients, by comparing the bacterial detection rate of this technique with that of blood culture. One milliliter of blood was collected from pediatric patients who developed fever with neutropenia following cancer chemotherapy. BrRNA RT-qPCR was perfo...

  14. Pathogens and diseases of freshwater mussels in the United States: Studies on bacterial transmission and depuration

    Science.gov (United States)

    Starliper, Clifford E.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

    2011-01-01

    Unionid mussels are recognized as important contributors to healthy aquatic ecosystems, as well as bioindicators of environmental perturbations. Because they are sedentary, filter feeding animals and require hosts (i.e., fishes) to transform embryonic glochidia, mussels are susceptible to direct adverse environmental parameters, and indirect parameters that restrict the timely presence of the host(s). Their numbers have declined in recent decades to a point that this fauna is regarded as one of the most imperiled in North America. The most significant threat to populations of native unionids in recent years has been the introduction and spread of zebra mussels Dreissena polymorpha. Many federal and state agencies, and private interests are now engaged in mussel conservation efforts, including collecting selected imperiled species from impacted rivers and lakes and propagating them at refuges for future population augmentations. One essential consideration with mussel propagation and their intensive culture at refugia is the prevention of pathogen introductions and control of diseases. Currently, there are few reports of etiological agents causing diseases among freshwater mussels; however, because of increased observations of mussel die-offs in conjunction with transfers of live animals between natural waters and refugia, disease problems can be anticipated to emerge. This review summarizes research to develop bacterial isolation techniques, study pathogen transmission between fish and mussels, identify causes of seasonal mussel die-offs, and develop non-destructive methods for pathogen detection. These efforts were done to develop disease preventative techniques for use by resource managers to avoid potential large-scale disease problems in restoration and population augmentation efforts among imperiled populations.

  15. Optimization of quantitative polymerase chain reactions for detection and quantification of eight periodontal bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Decat Ellen

    2012-12-01

    Full Text Available Abstract Background The aim of this study was to optimize quantitative (real-time polymerase chain reaction (qPCR assays for 8 major periodontal pathogens, i.e. Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Parvimonas micros, Porphyromonas gingivalis, Prevotella intermedia, Tanerella forsythia and Treponema denticola, and of the caries pathogen Streptococcus mutans. Results Eighteen different primer pairs were analyzed in silico regarding specificity (using BLAST analysis and the presence of secondary structures at primer binding sites (using mFOLD. The most specific and efficiently binding primer pairs, according to these analyses, were selected for qPCR-analysis to determine amplification efficiency, limit of quantification and intra-run reproducibility. For the selected primer pairs, one for each species, the specificity was confirmed by assessing amplification of DNA extracts from isolates of closely related species. For these primer pairs, the intercycler portability was evaluated on 3 different thermal cyclers (the Applied Biosystems 7300, the Bio-Rad iQ5 and the Roche Light Cycler 480. For all assays on the different cyclers, a good correlation of the standard series was obtained (i.e. r2 ≥ 0.98, but quantification limits varied among cyclers. The overall best quantification limit was obtained by using a 2 μl sample in a final volume of 10 μl on the Light Cycler 480. Conclusions In conclusion, the proposed assays allow to quantify the bacterial loads of S. mutans, 6 periodontal pathogenic species and the genus Fusobacterium.This can be of use in assessing periodontal risk, determination of the optimal periodontal therapy and evaluation of this treatment.

  16. Agrobacterium-Mediated Transformation of Tomato with rolB Gene Results in Enhancement of Fruit Quality and Foliar Resistance against Fungal Pathogens

    OpenAIRE

    Arshad, Waheed; Haq, Ihsan-ul-; Waheed, Mohammad Tahir; Mysore, Kirankumar S.; Mirza, Bushra

    2014-01-01

    Tomato (Solanum lycopersicum L.) is the second most important cultivated crop next to potato, worldwide. Tomato serves as an important source of antioxidants in human diet. Alternaria solani and Fusarium oxysporum cause early blight and vascular wilt of tomato, respectively, resulting in severe crop losses. The foremost objective of the present study was to generate transgenic tomato plants with rolB gene and evaluate its effect on plant morphology, nutritional contents, yield and resistance ...

  17. Bacteriophages with potential for inactivation of fish pathogenic bacteria: survival, host specificity and effect on bacterial community structure.

    Science.gov (United States)

    Pereira, Carla; Silva, Yolanda J; Santos, Ana L; Cunha, Angela; Gomes, Newton C M; Almeida, Adelaide

    2011-01-01

    Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

  18. Bacteriophages with Potential for Inactivation of Fish Pathogenic Bacteria: Survival, Host Specificity and Effect on Bacterial Community Structure

    Directory of Open Access Journals (Sweden)

    Yolanda J. Silva

    2011-11-01

    Full Text Available Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

  19. Investigation of environmental drivers of antimicrobial resistance in foodborne bacterial pathogens in antibiotic-free, all natural, pastured poultry flocks.

    Science.gov (United States)

    Question: In the absence of antibiotic use within pastured poultry production, what are potential environmental variables that drive the antimicrobial sensitivity patterns of bacterial foodborne pathogens isolated from these flocks? Purpose: The objective of this study is to examine environmental f...

  20. In vitro assessment of antimicrobial effect of methanolic extract of Peganum harmala against some important foodborne bacterial pathogens

    Directory of Open Access Journals (Sweden)

    T zeinali

    2016-01-01

    Full Text Available Foodborne bacterial pathogens play an important role in food infections/intoxications in human population. With ever increasing the number of antibiotic-resistant bacterial strains, there is an attempt to use the antimicrobial properties of herbs. Peganum harmala is a medicinal plant of Iraniantraditional medicine which was used as an antiseptic in the past. Amongthe foodborne bacterial pathogens, Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes are considered as the most important and hazardous pathogens. The aim of this study was to evaluate the antibacterial effect of methanolic extract of Peganum harmala against these bacteria in vitro. The minimum inhibitory concentration (MIC and minimum bactericidal concentrations (MBC of methanolic extract of Peganum harmala was determined against three foodborne bacterial pathogens by micro-dilution method in Muller-Hinton broth. According to the results, MIC for E. coli O157:H7 and S. Typhimurium was 1.56 mg/ml. In the case of L. monocytogenes, it was estimated at 0.78 mg/ml. Moreover, results revealed that MBC for these organisms was similar to MIC concentrations. Regarding the results, Peganum harmala can be used as an ingredient in the formula of the disinfectants applied in the food systems.

  1. Decay Of Bacterial Pathogens, Fecal Indicators, And Real-Time Quantitative PCR Genetic Markers In Manure-Amended Soils

    Science.gov (United States)

    This study examined persistence and decay of bacterial pathogens, fecal indicator bacteria (FIB), and emerging real-time quantitative PCR (qPCR) genetic markers for rapid detection of fecal pollution in manure-amended agricultural soils. Known concentrations of transformed green...

  2. Decay Of Bacterial Pathogen, Fecal Indicators, And Real-Time Quantitative PCR Genetic Markers In Manure Amended Soils

    Science.gov (United States)

    This study examined persistence and decay of bacterial pathogens, fecal indicator bacteria, and emerging real-time quantitative PCR (qPCR) genetic markers for rapid detection of fecal pollution in manre-amended agricultural soils. Known concentrations of transformed green fluore...

  3. Real-time PCR for detection and quantification of fungal and oomycete tomato pathogens in plant and soil samples

    NARCIS (Netherlands)

    Lievens, B.; Brouwer, M.; Vanachter, A.C.R.C.; Cammue, B.P.A.; Thomma, B.P.H.J.

    2006-01-01

    Although new, rapid detection and identification technologies are becoming available more and more for various plant pathogens, pathogen quantification remains one of the main challenges in the disease management of many crops. Currently, real-time polymerase chain reaction (PCR) is the most

  4. Bacterial and viral pathogen spectra of acute respiratory infections in under-5 children in hospital settings in Dhaka city.

    Directory of Open Access Journals (Sweden)

    Golam Sarower Bhuyan

    Full Text Available The study aimed to examine for the first time the spectra of viral and bacterial pathogens along with the antibiotic susceptibility of the isolated bacteria in under-5 children with acute respiratory infections (ARIs in hospital settings of Dhaka, Bangladesh. Nasal swabs were collected from 200 under-five children hospitalized with clinical signs of ARIs. Nasal swabs from 30 asymptomatic children were also collected. Screening of viral pathogens targeted ten respiratory viruses using RT-qPCR. Bacterial pathogens were identified by bacteriological culture methods and antimicrobial susceptibility of the isolates was determined following CLSI guidelines. About 82.5% (n = 165 of specimens were positive for pathogens. Of 165 infected cases, 3% (n = 6 had only single bacterial pathogens, whereas 43.5% (n = 87 cases had only single viral pathogens. The remaining 36% (n = 72 cases had coinfections. In symptomatic cases, human rhinovirus was detected as the predominant virus (31.5%, followed by RSV (31%, HMPV (13%, HBoV (11%, HPIV-3 (10.5%, and adenovirus (7%. Streptococcus pneumoniae was the most frequently isolated bacterial pathogen (9%, whereas Klebsiella pneumaniae, Streptococcus spp., Enterobacter agglomerans, and Haemophilus influenzae were 5.5%, 5%, 2%, and 1.5%, respectively. Of 15 multidrug-resistant bacteria, a Klebsiella pneumoniae isolate and an Enterobacter agglomerans isolate exhibited resistance against more than 10 different antibiotics. Both ARI incidence and predominant pathogen detection rates were higher during post-monsoon and winter, peaking in September. Pathogen detection rates and coinfection incidence in less than 1-year group were significantly higher (P = 0.0034 and 0.049, respectively than in 1-5 years age group. Pathogen detection rate (43% in asymptomatic cases was significantly lower compared to symptomatic group (P<0.0001. Human rhinovirus, HPIV-3, adenovirus, Streptococcus pneumonia, and Klebsiella pneumaniae had

  5. Concurrent Detection of Human Norovirus and Bacterial Pathogens in Water Samples from an Agricultural Region in Central California Coast

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    Peng Tian

    2017-08-01

    Full Text Available Bacterial pathogens and human norovirus (HuNoV are major cause for acute gastroenteritis caused by contaminated food and water. Public waterways can become contaminated from a variety of sources and flood after heavy rain events, leading to pathogen contamination of produce fields. We initiated a survey of several public watersheds in a major leafy green produce production region of the Central California Coast to determine the prevalence of HuNoV as well as bacterial pathogens. Moore swabs were used to collect environmental samples bi-monthly at over 30 sampling sites in the region. High prevalence of HuNoV and bacterial pathogens were detected in environmental water samples in the region. The overall detection rates of HuNoV, O157 Shiga toxin-producing Escherichia coli (STEC, non-O157 STEC, Salmonella, and Listeria were 25.58, 7.91, 9.42, 59.65, and 44.30%, respectively. The detection rates of Salmonella and L. monocytogenes were significantly higher in the spring. Fall and spring had elevated detection rates of O157 STEC. The overall detection rates of non-O157 STEC in the fall were lower than the other seasons but not significant. The overall detection rates of HuNoV were highest in fall, followed by spring and winter, with summer being lowest and significantly lower than other seasons. This study presented the first study of evaluating the correlation between the detection rate of HuNoV and the detection rates of four bacterial pathogens from environmental water. Overall, there was no significant difference in HuNoV detection rates between samples testing positive or negative for the four bacterial pathogens tested. Pathogens in animal-impacted and human-impacted areas were investigated. There were significant higher detection rates in animal-impacted areas than that of human-impacted areas for bacterial pathogens. However, there was no difference in HuNoV detection rates between these two areas. The overall detection levels of generic E

  6. Genetic Modulation of c-di-GMP Turnover Affects Multiple Virulence Traits and Bacterial Virulence in Rice Pathogen Dickeya zeae.

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    Yufan Chen

    Full Text Available The frequent outbreaks of rice foot rot disease caused by Dickeya zeae have become a significant concern in rice planting regions and countries, but the regulatory mechanisms that govern the virulence of this important pathogen remain vague. Given that the second messenger cyclic di-GMP (c-di-GMP is associated with modulation of various virulence-related traits in various microorganisms, here we set to investigate the role of the genes encoding c-di-GMP metabolism in the regulation of the bacterial physiology and virulence by construction all in-frame deletion mutants targeting the annotated c-di-GMP turnover genes in D. zeae strain EC1. Phenotype analyses identified individual mutants showing altered production of exoenzymes and phytotoxins, biofilm formation and bacterial motilities. The results provide useful clues and a valuable toolkit for further characterization and dissection of the regulatory complex that modulates the pathogenesis and persistence of this important bacterial pathogen.

  7. Genetic Modulation of c-di-GMP Turnover Affects Multiple Virulence Traits and Bacterial Virulence in Rice Pathogen Dickeya zeae.

    Science.gov (United States)

    Chen, Yufan; Lv, Mingfa; Liao, Lisheng; Gu, Yanfang; Liang, Zhibin; Shi, Zurong; Liu, Shiyin; Zhou, Jianuan; Zhang, Lianhui

    2016-01-01

    The frequent outbreaks of rice foot rot disease caused by Dickeya zeae have become a significant concern in rice planting regions and countries, but the regulatory mechanisms that govern the virulence of this important pathogen remain vague. Given that the second messenger cyclic di-GMP (c-di-GMP) is associated with modulation of various virulence-related traits in various microorganisms, here we set to investigate the role of the genes encoding c-di-GMP metabolism in the regulation of the bacterial physiology and virulence by construction all in-frame deletion mutants targeting the annotated c-di-GMP turnover genes in D. zeae strain EC1. Phenotype analyses identified individual mutants showing altered production of exoenzymes and phytotoxins, biofilm formation and bacterial motilities. The results provide useful clues and a valuable toolkit for further characterization and dissection of the regulatory complex that modulates the pathogenesis and persistence of this important bacterial pathogen.

  8. Neglected pathogens: bacterial infections in persons with human immunodeficiency virus infection. A review of the literature (1).

    Science.gov (United States)

    Fish, D N; Danziger, L H

    1993-01-01

    Bacterial infections, including those that cause infection in the healthy host as well as those that are more opportunistic, occur very commonly among persons infected with the human immunodeficiency virus (HIV). Bacterial infections are a direct result of the severe humoral and cellular immune defects found in these patients. Epidemiologic factors such as intravenous drug use and stage of HIV infection may also play important roles. Pulmonary, bloodstream, gastrointestinal, central nervous system, skin and soft tissue, and catheter-related infections are common, as are endocarditis, prostatitis, and others. Frequently reported pathogens are common organisms such as Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, and enteric gram-negative pathogens, as well as less typical ones such as Listeria monocytogenes and Nocardia sp. The frequency of infection is specific to organ system and pathogen, often being many times higher than in immunocompetent hosts. Prompt recognition and aggressive therapy are required to reduce morbidity and mortality due to these infections.

  9. One-step Multiplex RT-PCR Method for Simultaneous Detection of Seed Transmissible Bacteria and Viruses in Pepper and Tomato Seeds

    Directory of Open Access Journals (Sweden)

    Kyusik Jeong

    2011-04-01

    Full Text Available The aim of this study was to develop specific and sensitive PCR-based procedures for simultaneous detection of economically important plant seed infection pathogenic bacteria and virus, Xanthomonns campestris pv. vesicatoria (Xcv, Clavibacter michiganensis subsp. michiganensis (Cmm, Erwinia carotovora subsp. carotovora (Ecc, Pepper mild mottle virus (PMMoV and Tobacco mild green mosaic virus (TMGMV in pepper and tomato seeds. Most of pepper and tomato bacterial and virus diseases are responsible for germination and growth obstruction. PCR with arbitral primers: selection of specific primers, performance of PCR with specific primers and determination of the threshold level for pathogens detection. To detect simultaneously the Xcv, Cmm, Ecc, PMMoV and TMGMV in pepper and tomato seeds, five pairs (Cmm-F/R, Ecc-F/R, Xcv-F/R, PMMoV-F/R, TMGMV-F/R of specific primer were synthesized by primer-blast program. The multiplex PCR for the five pathogens in pepper and tomato seeds could detect specially without interference among primers and/or cDNA of plant seeds and other plant pathogens. The PCR result for pathogen detection using 20 commercial pepper and 10 tomato seed samples, Ecc was detected from 4 pepper and 2 tomato seed samples, PMMoV was detected from 1 pepper seed sample, and PMMoV and TMGMV were simultaneously detected from 1 pepper seed sample.

  10. An improved Agrobacterium mediated transformation in tomato ...

    African Journals Online (AJOL)

    Bacterial wilt is a devastating disease of tomato crop throughout the world. This disease is very dangerous in hot and humid regions, where it spreads with the irrigation water to whole field within days, which resulted in severe decline in yield. Two varieties of tomato were used for developing bacterial wilt resistance.

  11. Inflammasome-mediated cell death in response to bacterial pathogens that access the host cell cytosol: lessons from Legionella pneumophila

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    Cierra Nichole Casson

    2013-12-01

    Full Text Available Cell death can be critical for host defense against intracellular pathogens because it eliminates a crucial replicative niche, and pro-inflammatory cell death can alert neighboring cells to the presence of pathogenic organisms and enhance downstream immune responses. Pyroptosis is a pro-inflammatory form of cell death triggered by the inflammasome, a multi-protein complex that assembles in the cytosol to activate caspase-1. Inflammasome activation by pathogens hinges upon violation of the host cell cytosol by activities such as the use of pore-forming toxins, the use of specialized secretion systems, or the cytosolic presence of the pathogen itself. Recently, a non-canonical inflammasome has been described that activates caspase-11 and also leads to pro-inflammatory cell death. Caspase-11 is activated rapidly and robustly in response to violation of the cytosol by bacterial pathogens as well. In this mini-review, we describe the canonical and non-canonical inflammasome pathways that are critical for host defense against a model intracellular bacterial pathogen that accesses the host cytosol—Legionella pneumophila.

  12. COMPARATIVE EVALUATION OF CULTURE MEDIA FOR PATHOGEN ISOLATION OF PURULENT BACTERIAL MENINGITIS

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    Ya. V. Podkopaev

    2016-01-01

    Full Text Available The State Research Center for Applied Microbiology and Biotechnology has designed two nutrient media — chocolate agar and PBM-agar to isolate pathogens of purulent bacterial meningitis (PBM. In our previous research using collected microbial strains the media were shown to be highly susceptible and to provide the growth of Neisseria meningiti-dis, Streptococcus pneumoniae and Haemophilus influenzae strains, when inoculated with microbial suspensions containing single cells. When isolating Haemophilus influenzae, meningococci, and pneumococci the use of selective additives in both media assures selective isolation of required microorganisms, inhibiting contaminants. The objective of this research was to assess the media in bacteriological tests of clinical samples collected from the upper and lower respiratory tract in humans. The bacteriological plating of throat smear specimens (n = 90 from children and adults at the age of 0 to 66 with disorder of the upper respiratory tract on chocolate agar, PBM-agar and on a control medium in the absence of selective additives resulted in the equal amount of microbial cultures isolated. Of 154 isolated cultures 2, 23 and 9 were attributed to Neisseria meningitidis, Streptococcus pneumoniae and Haemophilus influenzae, respectively. The plating of throat smears (n = 10 from healthy people at the age of 30 to 55 on the analyzable and control media in the presence of additives allowed us to selectively isolate Haemophilus influenzae and Streptococcus pneumoniae cultures without a quantitative loss, with contaminants inhibited. By their growth characteristics chocolate agar and PBM-agar were highly competitive with reference media being used in clinical practice for isolating main causative agents of purulent bacterial meningitis.

  13. Prevalence of Gram-negative Pathogens and their antimicrobial susceptibility in bacterial meningitis in pediatric cases

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    Yash Pal Chugh

    2012-07-01

    Full Text Available The present study was conducted to find out the prevalence and spectrum of Gram negative pathogens causing bacterial meningitis and their antimicrobial susceptibility pattern in a tertiary care hospital. The cerebrospinal fluid (CSF (3-5 ml was collected from 638 admitted children clinically suspected of septic meningitis. Bacterial isolates were identified and antimicrobial susceptibility was assessed by the Kirby-Bauer disk diffusion method. Of the 638 samples tested 102 (15.99% were culture positive. Male to female (M:F ratio was 1.62:1. The maximum incidence of 45 (44.12% cases was found in children (1-12 yrs; in institutional deliveries the incidence was 58 (56.86% cases. Further, the incidence of 51 cases was found from May to August. Escherichia coli (E. coli were commonest, seen in 9 (25% cases followed by Acinetobacter spp., Citrobacter spp. and Klebsiella spp. with 6 (16.67% cases each. Enterobacter spp., Neisseria spp. and Pseudomonas aeruginosa were isolated in 3 (8.33% cases each. E. coli, Acinetobacter spp, Citrobacter spp and Klebsiella spp isolates were 100% susceptible to meropenem, piperacillin-tazobactam and cefoperazone-sulbactam and 100% resistant to cotrimoxazole and tetracycline. All strains of Neisseria spp, Enterobacter spp and Pseudomonas spp. were 100% susceptible to meropenem followed by gatifloxacin. These were 100% resistant to tetracycline and cotrimoxazole. Neisseria spp. were also 100% susceptible to pristinamycin. In septic meningitis Gram negative organisms are less common (35.29%. Of the isolates, more common Gram negative isolates included E. coli, Acinetobacter Spp., Citrobacter Spp., and Klebsiella spp. and these isolates were 100% susceptible to meropenem, piperacillin-tazobacatam and cefoperazone-sulbactam. Hence, empirical therapy should be formulated according to antimicrobial susceptibility patterns.

  14. The bioactivity of plant extracts against representative bacterial pathogens of the lower respiratory tract

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    Bocanegra-García Virgilio

    2009-06-01

    Full Text Available Abstract Background Lower respiratory tract infections are a major cause of illness and death. Such infections are common in intensive care units (ICU and their lethality persists despite advances in diagnosis, treatment and prevention. In Mexico, some plants are used in traditional medicine to treat respiratory diseases or ailments such as cough, bronchitis, tuberculosis and other infections. Medical knowledge derived from traditional societies has motivated searches for new bioactive molecules derived from plants that show potent activity against bacterial pathogens. Therefore, the aim of this study was to evaluate the effect of hexanic, chloroformic (CLO, methanolic (MET and aqueous extracts from various plants used in Mexican traditional medicine on various microorganisms associated with respiratory disease. Methods thirty-five extracts prepared from nine plants used in Mexican traditional medicine for the treatment of respiratory infections were evaluated against 15 control bacterial species and clinical isolates. Results Both chloroformic (CLO and methanolic (MET extracts of Larrea tridentata were active against Methicillin-resistant S. aureus, B. subtilis and L. monocytogenes. A MET extract of L. tridentata was also active against S. aureus, S. pneumoniae, S. maltophilia, E. faecalis and H. influenzae and the CLO extract was active against A. baumannii. An Aqueous extract of M. acumitata and a MET extract of N. officinale were active against S. pneumoniae. CLO and MET extracts of L. tridentata were active against clinical isolates of S. aureus, S. pneumoniae and E. faecalis. Conclusion Overall, our results support the potential use of L. tridentata as a source of antibacterial compounds.

  15. Prevalence and antibiotic resistance of bacterial pathogens isolated from childhood diarrhoea in four provinces of Kenya.

    Science.gov (United States)

    Sang, Willie Kipkemboi; Oundo, Valerie; Schnabel, David

    2012-07-23

    Diarrhoea is one of the main causes of morbidity and mortality among children in sub-Saharan Africa, and one of the main causes of hospital admissions in rural areas of Kenya. In Kenya, antimicrobial resistance surveillance has been conducted only at the institutional levels, with limited sharing of information and analysis of data. As a result, the actual scale of regional or national antimicrobial drug resistance is not well defined. Stool samples were collected between 1 October 2007 and 30 September 2008 from a total of 651 outpatients with diarrhoea who were under five years of age in four provinces of Kenya.  Conventional, biochemical methods, multiplex PCR and antimicrobial susceptibility were conducted to identify the bacterial causes and virulence factors in the isolates, respectively.  Of the 651 patients screened, we identified the causes of 115 cases (17.7%) as follows: Pathogenic E. coli (11.2%) [enteroaggregative (8.9%), enterotoxigenic (1.2%), enteroinvasive (0.6%), shigatoxigenic (0.5%)], Salmonella (3.5%), Shigella (2%) and Vibrio cholera O1 (0.7%). The highest levels of resistance among the E. coli isolates were observed in ampicillin and trimethoprim/sulphamethoxazole each at 95% followed by tetracycline at 81%. Shigella isolate levels of resistance ranged from 80% to 100% for ampicillin, tetracycline and trimethoprim/sulphamethoxazole. The highest prevalence of antimicrobial resistance was to ampicillin followed by trimethoprim/sulphamethoxazole and tetracycline. Though still at low levels, the major concern from our findings is the emerging resistance of enteric pathogens that was observed to quinolones (ciprofloxacin, nalidixic acid, norfloxacin) and gentamycin.

  16. Cronobacter, the emergent bacterial pathogen Enterobacter sakazakii comes of age; MLST and whole genome sequence analysis.

    Science.gov (United States)

    Forsythe, Stephen J; Dickins, Benjamin; Jolley, Keith A

    2014-12-16

    Following the association of Cronobacter spp. to several publicized fatal outbreaks in neonatal intensive care units of meningitis and necrotising enterocolitis, the World Health Organization (WHO) in 2004 requested the establishment of a molecular typing scheme to enable the international control of the organism. This paper presents the application of Next Generation Sequencing (NGS) to Cronobacter which has led to the establishment of the Cronobacter PubMLST genome and sequence definition database (http://pubmlst.org/cronobacter/) containing over 1000 isolates with metadata along with the recognition of specific clonal lineages linked to neonatal meningitis and adult infections Whole genome sequencing and multilocus sequence typing (MLST) has supports the formal recognition of the genus Cronobacter composed of seven species to replace the former single species Enterobacter sakazakii. Applying the 7-loci MLST scheme to 1007 strains revealed 298 definable sequence types, yet only C. sakazakii clonal complex 4 (CC4) was principally associated with neonatal meningitis. This clonal lineage has been confirmed using ribosomal-MLST (51-loci) and whole genome-MLST (1865 loci) to analyse 107 whole genomes via the Cronobacter PubMLST database. This database has enabled the retrospective analysis of historic cases and outbreaks following re-identification of those strains. The Cronobacter PubMLST database offers a central, open access, reliable sequence-based repository for researchers. It has the capacity to create new analysis schemes 'on the fly', and to integrate metadata (source, geographic distribution, clinical presentation). It is also expandable and adaptable to changes in taxonomy, and able to support the development of reliable detection methods of use to industry and regulatory authorities. Therefore it meets the WHO (2004) request for the establishment of a typing scheme for this emergent bacterial pathogen. Whole genome sequencing has additionally shown a range

  17. Bacterial pathogen gene abundance and relation to recreational water quality at seven Great Lakes beaches

    Science.gov (United States)

    Oster, Ryan J.; Wijesinghe, Rasanthi U.; Fogarty, Lisa Reynolds; Haack, Sheridan K.; Fogarty, Lisa R.; Tucker, Taaja R.; Riley, Stephen

    2014-01-01

    Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.

  18. Simultaneous Detection of Key Bacterial Pathogens Related to Pneumonia and Meningitis Using Multiplex PCR Coupled With Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2018-04-01

    Full Text Available Pneumonia and meningitis continue to present an enormous public health burden and pose a major threat to young children. Among the causative organisms of pneumonia and meningitis, bacteria are the most common causes of serious disease and deaths. It is challenging to accurately and rapidly identify these agents. To solve this problem, we developed and validated a 12-plex PCR coupled with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS method (bacterial pathogen-mass spectrometry, BP-MS that can be used to simultaneously screen for 11 key bacterial pathogens related to pneumonia and meningitis. Forty-six nasopharyngeal swabs and 12 isolates were used to determine the specificity of the method. The results showed that, using the BP-MS method, we could accurately identify the expected bacteria without cross-reactivity with other pathogens. For the 11 target bacterial pathogens, the analytical sensitivity of the BP-MS method was as low as 10 copies/reaction. To further evaluate the clinical effectiveness of this method, 204 nasopharyngeal swabs from hospitalized children with suspected pneumonia were tested using this method. In total, 81.9% (167/204 of the samples were positive for at least one of the 11 target pathogens. Among the 167 bacteria-positive samples, the rate of multiple infections was 55.7% (93/167, and the most frequent combination was Streptococcus pneumoniae with Haemophilus influenzae, representing 46.2% (43/93 two-pathogen mixed infections. We used real-time PCR and nested PCR to confirm positive results, with identical results obtained for 81.4% (136/167 of the samples. The BP-MS method is a sensitive and specific molecular detection technique in a multiplex format and with high sample throughput. Therefore, it will be a powerful tool for pathogen screening and antibiotic selection at an early stage of disease.

  19. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae-Young [National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 (Canada)], E-mail: daeyoung.lee@ec.gc.ca; Lauder, Heather; Cruwys, Heather; Falletta, Patricia [National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 (Canada); Beaudette, Lee A. [Environmental Science and Technology Centre, Environment Canada, 335 River Road South, Ottawa, Ontario, K1A 0H3 (Canada)], E-mail: lee.beaudette@ec.gc.ca

    2008-07-15

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 10{sup 3}A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater.

  20. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens

    International Nuclear Information System (INIS)

    Lee, Dae-Young; Lauder, Heather; Cruwys, Heather; Falletta, Patricia; Beaudette, Lee A.

    2008-01-01

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 10 3 A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater

  1. Chlorhexidine Digluconate Effects on Planktonic Growth and Biofilm Formation in Some Field Isolates of Animal Bacterial Pathogens

    Science.gov (United States)

    Ebrahimi, Azizollah; Hemati, Majid; Habibian Dehkordi, Saeed; Bahadoran, Shahab; Khoshnood, Sheida; Khubani, Shahin; Dokht Faraj, Mahdi; Hakimi Alni, Reza

    2014-01-01

    Background: To study chlorhexidine digluconate disinfectant effects on planktonic growth and biofilm formation in some bacterial field isolates from animals. Objectives: The current study investigated chlorhexidine digluconate effects on planktonic growth and biofilm formation in some field isolates of veterinary bacterial pathogens. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus. aureus and Streptococcus agalactiae (10 isolates for each) were examined for chlorhexidine digluconate effects on biofilm formation and planktonic growth using microtiter plates. In all of the examined strains in the presence of chlorhexidine digluconate, biofilm development and planktonic growth were affected at the same concentrations of the disinfectant. Results: Chlorhexidine digluconate inhibited the planktonic growth of different bacterial species at sub-MICs. But they were able to induce biofilm development of the E. coli, Salmonella spp., S. aureus and Str. agalactiae strains. Conclusions: Bacterial resistance against chlorhexidine is increasing. Sub-MIC doses of chlorhexidine digluconate can stimulate the formation of biofilm strains. PMID:24872940

  2. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

    Directory of Open Access Journals (Sweden)

    Mari Narusaka

    Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.

  3. Zoonotic vector-borne bacterial pathogens in California mountain lions (Puma concolor), 1987-2010.

    Science.gov (United States)

    Girard, Yvette A; Swift, Pamela; Chomel, Bruno B; Kasten, Rickie W; Fleer, Katryna; Foley, Janet E; Torres, Steven G; Johnson, Christine K

    2012-11-01

    Sera collected from 442 mountain lions in 48 California counties between the years of 1987 and 2010 were tested using immunofluorescence assays and agglutination tests for the presence of antibodies reactive to Yersinia pestis, Francisella tularensis, Bartonella henselae, Borrelia burgdorferi, and Anaplasma phagocytophilum antigens. Data were analyzed for spatial and temporal trends in seropositivity. Seroprevalences for B. burgdorferi (19.9%) and B. henselae (37.1%) were relatively high, with the highest exposure in the Central Coast region for B. henselae. B. henselae DNA amplified in mountain lion samples was genetically similar to human-derived Houston-1 and domestic cat-derived U4 B. henselae strains at the gltA and ftsZ loci. The statewide seroprevalences of Y. pestis (1.4%), F. tularensis (1.4%), and A. phagocytophilum (5.9%), were comparatively low. Sera from Y. pestis- and F. tularensis-seropositive mountain lions were primarily collected in the Eastern and Western Sierra Nevada, and samples reactive to Y. pestis antigen were collected exclusively from adult females. Adult age (≥ 2 years) was a risk factor for B. burgdorferi exposure. Over 70% of tested animals were killed on depredation permits, and therefore were active near areas with livestock and human residential communities. Surveillance of mountain lions for these bacterial vector-borne and zoonotic agents may be informative to public health authorities, and the data are useful for detecting enzootic and peridomestic pathogen transmission patterns, particularly in combination with molecular characterization of the infecting organisms.

  4. Antimicrobial potential of Halophilic actinomycetes against multi drug resistant (MDR) ventilator associated pneumonia causing bacterial pathogens.

    Science.gov (United States)

    Aslam, Sana; Sajid, Imran

    2016-03-01

    A collection of forty halophilic actinomycetes isolated from water and mud samples of the saline lake at Kalar Kahar, salt range, Pakistan, was screened to investigate their antimicrobial potential against multi drug resistant (MDR) ventilator associated pneumonia causing bacterial pathogens. The isolates exhibited significant tolerance to alkaline conditions and grew well at pH 9-11. The taxonomic status of the isolated strains was determined by morphological, biochemical and physiological characterization and by 16s rRNA gene sequencing. The results revealed that majority of the isolates (90%) belong to the genus Streptomyces. Most of the isolates exhibited remarkable antimicrobial activity up to 20mm zone of inhibition against MDR ventilator associated pneumonia causing bacteria including Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Enterobacter and Acinetobacter spp. Additionally the isolates showed moderate to high cytotoxicity in the range of 40 to 80% larval mortality against Artemia salina in a micro well cytotoxicity assay. The chemical screening or the so called metabolic fingerprinting of the methanolic extracts of each isolate, by thin layer chromatography (TLC) using various staining reagents and by high performance liquid chromatography (HPLC-UV), indicated an impressive diversity of the compounds produced by these strains. The study reveals that these halophilic actinomycetes are a promising source of bioactive compounds. The preparative scale fermentation, isolation, purification and structure elucidation of the compounds produced by them may yield novel antimicrobial or chemotherapeutic agents.

  5. Microfluidic system for the identification of bacterial pathogens causing urinary tract infections

    Science.gov (United States)

    Becker, Holger; Hlawatsch, Nadine; Haraldsson, Tommy; van der Wijngaart, Wouter; Lind, Anders; Malhotra-Kumar, Surbi; Turlej-Rogacka, Agata; Goossens, Herman

    2015-03-01

    Urinary tract infections (UTIs) are among the most common bacterial infections and pose a significant healthcare burden. The growing trend in antibiotic resistance makes it mandatory to develop diagnostic kits which allow not only the determination of a pathogen but also the antibiotic resistances. We have developed a microfluidic cartridge which takes a direct urine sample, extracts the DNA, performs an amplification using batch-PCR and flows the sample over a microarray which is printed into a microchannel for fluorescence detection. The cartridge is injection-molded out of COP and contains a set of two-component injection-molded rotary valves to switch between input and to isolate the PCR chamber during thermocycling. The hybridization probes were spotted directly onto a functionalized section of the outlet microchannel. We have been able to successfully perform PCR of E.coli in urine in this chip and perform a fluorescence detection of PCR products. An upgraded design of the cartridge contains the buffers and reagents in blisters stored on the chip.

  6. The role ofLinguatula serratanymph in transmission of enteric bacterial pathogens to internal organs in sheep.

    Science.gov (United States)

    Hajimohammadi, Bahador; Eslami, Gilda; Khalatbari-Limaki, Sepideh; Ehrampoush, Mohammad Hasan; Oryan, Ahmad; Zandi, Hengameh; Dehghan, Hamid Reza

    2017-09-01

    Linguatula serrata is a worldwide zoonotic parasite belong to phylum Athropoda. When the eggs are swallowed by intermediate host, the larvae are released in intestine and reach the mesenteric lymph nodes (MLNs) and occasionally liver, lungs, heart, kidneys, spleen, and other body organs by the blood and lymph circulation. There are a few evidences showing transmission of microorganisms by migrating L. serrata. The aim of this study was to determine the role of L. serrata nymph in transmission of enteric bacterial pathogens to internal organs of sheep. For this purpose 11 parasite positive and 11 parasite negative MLNs to L. serrata were obtained from the native slaughtered sheep and were examined microbiologically in terms of bacterial contamination. The average total bacterial count and Escherichia coli count in the parasite positive samples were respectively 6.7 and 3.3 times higher than parasite negative ones ( P  < 0.05). However no significant differences were found for Salmonella and intestinal enterococci between parasite positive/negative samples. This indicates that L. serrata nymphs play as vehicles for bacteria and so contaminate offal. L. serrata nymphs transfer some bacterial agents to internal organs and enhance post mortem spoilage of the infected organs. It is also able to transfer some bacterial pathogens to internal organs which could potentially be the etiology of severe infectious or even zoonotic diseases. Especially in some regions where the consumption of raw or semi-cooked lymph nodes and other visceral organs are common.

  7. Development and application of a multiplex PCR assay for rapid detection of 4 major bacterial pathogens in ducks.

    Science.gov (United States)

    Wei, B; Cha, S-Y; Kang, M; Park, I-J; Moon, O-K; Park, C-K; Jang, H-K

    2013-05-01

    Infections with Pasteurella multocida, Salmonella enterica, Riemerella anatipestifer, and Escherichia coli result in high morbidity and mortality, which cause significant economic loss in the poultry industry. It can be difficult to distinguish these pathogens based on clinical signs because these pathogens can cause similar clinical signs and coinfections can occur. Thus, rapid and sensitive detection of these 4 major bacterial pathogens are important in ducks. The aim of this study was to develop a multiplex PCR (mPCR) assay for simultaneously detecting and identifying these 4 pathogenic bacteria in a single tube reaction. The target genes used were KMT1 of P. multocida, the invasion protein gene of S. enterica, 16S rDNA of R. anatipestifer, and the alkaline phosphatase gene of E. coli. The detection limit of the assay for all bacterial DNA was 10 pg. The mPCR did not produce any nonspecific amplification products when tested against other related pathogens, including Staphylococcus aureus, Streptococcus pyogenes, Clostridium perfringens, Mycoplasma gallinarum, Mycoplasma synoviae, and Mycoplasma gallisepticum, which can also infect ducks. We applied mPCR to field samples, and the results were the same as the single PCR results. These results suggest that mPCR for the 4 bacteria is a useful and rapid technique to apply to field samples.

  8. Simultaneous Detection of Brown Rot- and Soft Rot-Causing Bacterial Pathogens from Potato Tubers Through Multiplex PCR.

    Science.gov (United States)

    Ranjan, R K; Singh, Dinesh; Baranwal, V K

    2016-11-01

    Ralstonia solanacearum (Smith) Yabuuchi et al. and Erwinia carotovora subsp. carotovora (Jones) Bergey et al. (Pectobacterium carotovorum subsp. carotovorum) are the two major bacterial pathogens of potato causing brown rot (wilt) and soft rot diseases, respectively, in the field and during storage. Reliable and early detection of these pathogens are keys to avoid occurrence of these diseases in potato crops and reduce yield loss. In the present study, multiplex polymerase chain reaction (PCR) protocol was developed for simultaneous detection of R. solanacearum and E. carotovora subsp. carotovora from potato tubers. A set of oligos targeting the pectatelyase (pel) gene of E. carotovora subsp. carotovora and the universal primers based on 16S r RNA gene of R. solanacearum were used. The standardized multiplex PCR protocol could detect R. solanacearum and E. carotovora subsp. carotovora up to 0.01 and 1.0 ng of genomic DNA, respectively. The protocol was further validated on 96 stored potato tuber samples, collected from different potato-growing states of India, viz. Uttarakhand, Odisha, Meghalaya and Delhi. 53.1 % tuber samples were positive for R. solanacearum, and 15.1 % of samples were positive for E. carotovora subsp. carotovora, and both the pathogens were positive in 26.0 % samples when BIO-PCR was used. This method offers sensitive, specific, reliable and fast detection of two major bacterial pathogens from potato tubers simultaneously, particularly pathogen-free seed certification in large scale.

  9. [Survey of the presence of bacterial pathogens in foods sold at retail stores in the city of Cassino].

    Science.gov (United States)

    Langiano, E; Atrei, P; La Torre, G; De Vito, E; Ricciardi, G

    2002-01-01

    The presence of bacterial food pathogens was evaluated in 154 food samples collected from supermarkets and butchers in the city of Cassino (South-Central Italy). Food pathogens were identified in 17.5% of the total food samples. In the raw meat samples, 24.6% tested positives for Listeria monocytogenes, 4.3% for Salmonella and 2.9% for Escherichia coli O157. Y. enterocolitica, only investigated in pork meat, was identified in 7.4% of the samples. In poultry, L. monocytogenes was identified in 55% of the samples.

  10. Presence of pathogenic Escherichia coli is correlated with bacterial community diversity and composition on pre-harvest cattle hides.

    Science.gov (United States)

    Chopyk, Jessica; Moore, Ryan M; DiSpirito, Zachary; Stromberg, Zachary R; Lewis, Gentry L; Renter, David G; Cernicchiaro, Natalia; Moxley, Rodney A; Wommack, K Eric

    2016-03-22

    Since 1982, specific serotypes of Shiga toxin-producing Escherichia coli (STEC) have been recognized as significant foodborne pathogens acquired from contaminated beef and, more recently, other food products. Cattle are the major reservoir hosts of these organisms, and while there have been advancements in food safety practices and industry standards, STEC still remains prevalent within beef cattle operations with cattle hides implicated as major sources of carcass contamination. To investigate whether the composition of hide-specific microbial communities are associated with STEC prevalence, 16S ribosomal RNA (rRNA) bacterial community profiles were obtained from hide and fecal samples collected from a large commercial feedlot over a 3-month period. These community data were examined amidst an extensive collection of prevalence data on a subgroup of STEC that cause illness in humans, referred to as enterohemorrhagic E. coli (EHEC). Fecal 16S rRNA gene OTUs (operational taxonomic units) were subtracted from the OTUs found within each hide 16S rRNA amplicon library to identify hide-specific bacterial populations. Comparative analysis of alpha diversity revealed a significant correlation between low bacterial diversity and samples positive for the presence of E. coli O157:H7 and/or the non-O157 groups: O26, O111, O103, O121, O45, and O145. This trend occurred regardless of diversity metric or fecal OTU presence. The number of EHEC serogroups present in the samples had a compounding effect on the inverse relationship between pathogen presence and bacterial diversity. Beta diversity data showed differences in bacterial community composition between samples containing O157 and non-O157 populations, with certain OTUs demonstrating significant changes in relative abundance. The cumulative prevalence of the targeted EHEC serogroups was correlated with low bacterial community diversity on pre-harvest cattle hides. Understanding the relationship between indigenous hide

  11. Inducible Expression of the De-Novo Designed Antimicrobial Peptide SP1-1 in Tomato Confers Resistance to Xanthomonas campestris pv. vesicatoria.

    Directory of Open Access Journals (Sweden)

    Areli Herrera Diaz

    Full Text Available Antimicrobial peptides (AMPs are small peptides with less than 50 amino acids and are part of the innate immune response in almost all organisms, including bacteria, vertebrates, invertebrates and plants. AMPs are active against a broad-spectrum of pathogens. The inducible expression of AMPs in plants is a promising approach to combat plant pathogens with minimal negative side effects, such as phytotoxicity or infertility. In this study, inducible expression of the de-novo designed AMP SP1-1 in Micro Tom tomato protected tomato fruits against bacterial spot disease caused by Xanthomonas campestris pv. vesicatoria. The peptide SP1-1 was targeted to the apoplast which is the primary infection site for plant pathogens, by fusing SP1-1 peptide to the signal peptide RsAFP1 of radish (Raphanus sativus. The pathogen inducibility of the expression was enabled by using an optimized inducible 4XW2/4XS promoter. As a result, the tomato fruits of independently generated SP1-1 transgenic lines were significantly more resistant to X. campestris pv. vesicatoria than WT tomato fruits. In transgenic lines, bacterial infection was reduced up to 65% in comparison to the infection of WT plants. Our study demonstrates that the combination of the 4XW2/4XS cis-element from parsley with the synthetic antimicrobial peptide SP1-1 is a good alternative to protect tomato fruits against infections with X. campestris pv. vesicatoria.

  12. A novel multiplex PCR assay for simultaneous detection of nine clinically significant bacterial pathogens associated with bovine mastitis.

    Science.gov (United States)

    Ashraf, Aqeela; Imran, Muhammad; Yaqub, Tahir; Tayyab, Muhammad; Shehzad, Wasim; Thomson, Peter C

    2017-06-01

    For rapid and simultaneous detection of nine bovine mastitic pathogens, a sensitive and specific multiplex PCR assay was developed. The assay was standardized using reference strains and validated on mastitic milk cultures which were identified to species level based on 16S rRNA sequencing. Multiplex PCR assay also efficiently detected the target bacterial strains directly from milk. The detection limit of the assay was up to 50 pg for DNA isolated from pure cultures and 10 4  CFU/ml for spiked milk samples. As estimated by latent class analysis, the assay was sensitive up to 88% and specific up to 98% for targeted mastitic pathogens, compared with the bacterial culture method and the 16S rRNA sequence analysis. This novel molecular assay could be useful for monitoring and maintaining the bovine udder health, ensuring the bacteriological safety of milk, and conducting epidemiological studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Small non-coding RNAs: new insights in modulation of host immune response by intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Waqas Ahmed

    2016-10-01

    Full Text Available Pathogenic bacteria possess intricate regulatory networks that temporally control the production of virulence factors, and enable the bacteria to survive and proliferate within host cell. Small non-coding RNAs (sRNAs have been identified as important regulators of gene expression in diverse biological contexts. Recent research has shown bacterial sRNAs involved in growth and development, cell proliferation, differentiation, metabolism, cell signaling and immune response through regulating protein–protein interactions or via their ability to base pair with RNA and DNA. In this review, we provide a brief overview of mechanism of action employed by immune-related sRNAs, their known functions in immunity, and how they can be integrated into regulatory circuits that govern virulence, which will facilitates to understand pathogenesis and the development of novel, more effective therapeutic approaches to treat infections caused by intracellular bacterial pathogens.

  14. Enteric bacterial pathogens in children with diarrhea in Niger: diversity and antimicrobial resistance.

    Directory of Open Access Journals (Sweden)

    Céline Langendorf

    Full Text Available Although rotavirus is the leading cause of severe diarrhea among children in sub-Saharan Africa, better knowledge of circulating enteric pathogenic bacteria and their antimicrobial resistance is crucial for prevention and treatment strategies.As a part of rotavirus gastroenteritis surveillance in Maradi, Niger, we performed stool culture on a sub-population of children under 5 with moderate-to-severe diarrhea between April 2010 and March 2012. Campylobacter, Shigella and Salmonella were sought with conventional culture and biochemical methods. Shigella and Salmonella were serotyped by slide agglutination. Enteropathogenic Escherichia coli (EPEC were screened by slide agglutination with EPEC O-typing antisera and confirmed by detection of virulence genes. Antimicrobial susceptibility was determined by disk diffusion. We enrolled 4020 children, including 230 with bloody diarrhea. At least one pathogenic bacterium was found in 28.0% of children with watery diarrhea and 42.2% with bloody diarrhea. Mixed infections were found in 10.3% of children. EPEC, Salmonella and Campylobacter spp. were similarly frequent in children with watery diarrhea (11.1%, 9.2% and 11.4% respectively and Shigella spp. were the most frequent among children with bloody diarrhea (22.1%. The most frequent Shigella serogroup was S. flexneri (69/122, 56.5%. The most frequent Salmonella serotypes were Typhimurimum (71/355, 20.0%, Enteritidis (56/355, 15.8% and Corvallis (46/355, 13.0%. The majority of putative EPEC isolates was confirmed to be EPEC (90/111, 81.1%. More than half of all Enterobacteriaceae were resistant to amoxicillin and co-trimoxazole. Around 13% (46/360 Salmonella exhibited an extended-spectrum beta-lactamase phenotype.This study provides updated information on enteric bacteria diversity and antibiotic resistance in the Sahel region, where such data are scarce. Whether they are or not the causative agent of diarrhea, bacterial infections and their antibiotic

  15. Demonstration of the metaphylactic use of gamithromycin against bacterial pathogens associated with bovine respiratory disease in a multicentre farm trial

    OpenAIRE

    Baggott, D.; Casartelli, A.; Fraisse, F.; Manavella, C.; Marteau, R.; Rehbein, S.; Wiedemann, M.; Yoon, S.

    2011-01-01

    On five commercial cattle rearing sites across Europe, a total of 802 young cattle at high risk of developing bovine respiratory disease (BRD) associated with the bacterial pathogens Mannheimia haemolytica or Pasteurella multocida and/or Mycoplasma bovis were enrolled into a multicentre, controlled field trial. Half were treated with a single dose of gamithromycin at 6 mg/kg bodyweight by subcutaneous injection and half received an injection of a saline placebo as the control. All animals wer...

  16. Implications of bacterial viruses on pathogenic bacteria: from natural microbial communities to therapeutic applications

    OpenAIRE

    Örmälä-Odegrip, Anni-Maria

    2015-01-01

    Bacterial viruses (i.e. phages) are ubiquitous intracellular parasites of bacteria, that along with protist grazers account for majority of bacterial mortality in nature. Phages impose strong selection for bacterial phage-resistance, which is often coupled with fitness costs on bacterial traits such as growth ability, virulence or motility. Traditionally phage-host interactions have been studied with two species systems in the laboratory, neglecting the complex web of interactions presen...

  17. Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators

    Science.gov (United States)

    Haack, S.K.; Duris, J.W.; Fogarty, L.R.; Kolpin, D.W.; Focazio, M.J.; Furlong, E.T.; Meyer, M.T.

    2009-01-01

    The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes. Genes tested included esp (indicating human-pathogenic ENT) and nine genes associated with various animal sources of shiga-toxin-producing EC (STEC). Fecal pollution was indicated by genes and/or chemicals for 14 of the 18 tested samples, with little relation to FIB standards. Of 13 samples with <50 EC 100 mL-1, human pharmaceuticals or chemical indicators of wastewater treatment plant effluent occurred in six, veterinary antibiotics were detected in three, and stx1 or stx2 genes (indicating varying animal sources of STEC) were detected in eight. Only the EC eaeA gene was positively correlated with FIB concentrations. Human-source fecal pollution was indicated by the esp gene and the human pharmaceutical carbamazepine in one of the nine samples that met all FIB recreational water quality standards. Escherichia coli rfbO157 and stx2c genes, which are typically associated with cattle sources and are of potential human health significance, were detected in one sample in the absence of tested chemicals. Chemical and gene-based indicators of fecal contamination may be present even when FIB standards are met, and some may, unlike FIB, indicate potential sources. Application of multiple water quality indicators with variable environmental persistence and fate may yield greater confidence in fecal pollution assessment and may inform remediation decisions. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  18. Innate immunity against Granulibacter bethesdensis, an emerging gram-negative bacterial pathogen.

    Science.gov (United States)

    Zarember, Kol A; Marshall-Batty, Kimberly R; Cruz, Anna R; Chu, Jessica; Fenster, Michael E; Shoffner, Adam R; Rogge, Larissa S; Whitney, Adeline R; Czapiga, Meggan; Song, Helen H; Shaw, Pamela A; Nagashima, Kunio; Malech, Harry L; DeLeo, Frank R; Holland, Steven M; Gallin, John I; Greenberg, David E

    2012-03-01

    Acetic acid bacteria were previously considered nonpathogenic in humans. However, over the past decade, five genera of Acetobacteraceae have been isolated from patients with inborn or iatrogenic immunodeficiencies. Here, we describe the first studies of the interactions of the human innate immune system with a member of this bacterial family, Granulibacter bethesdensis, an emerging pathogen in patients with chronic granulomatous disease (CGD). Efficient phagocytosis of G. bethesdensis by normal and CGD polymorphonuclear leukocytes (CGD PMN) required heat-labile serum components (e.g., C3), and binding of C3 and C9 to G. bethesdensis was detected by immunoblotting. However, this organism survived in human serum concentrations of ≥90%, indicating a high degree of serum resistance. Consistent with the clinical host tropism of G. bethesdensis, CGD PMN were unable to kill this organism, while normal PMN, in the presence of serum, reduced the number of CFU by about 50% after a 24-h coculture. This finding, together with the observations that G. bethesdensis was sensitive to H(2)O(2) but resistant to LL-37, a human cationic antimicrobial peptide, suggests an inherent resistance to O(2)-independent killing. Interestingly, 10 to 100 times greater numbers of G. bethesdensis were required to achieve the same level of reactive oxygen species (ROS) production induced by Escherichia coli in normal PMN. In addition to the relative inability of the organism to elicit production of PMN ROS, G. bethesdensis inhibited both constitutive and FAS-induced PMN apoptosis. These properties of reduced PMN activation and resistance to nonoxidative killing mechanisms likely play an important role in G. bethesdensis pathogenesis.

  19. In vitro and in vivo profiles of ACH-702, an isothiazoloquinolone, against bacterial pathogens.

    Science.gov (United States)

    Pucci, Michael J; Podos, Steven D; Thanassi, Jane A; Leggio, Melissa J; Bradbury, Barton J; Deshpande, Milind

    2011-06-01

    ACH-702, a novel isothiazoloquinolone (ITQ), was assessed for antibacterial activity against a panel of Gram-positive and Gram-negative clinical isolates and found to possess broad-spectrum activity, especially against antibiotic-resistant Gram-positive strains, including methicillin-resistant Staphylococcus aureus (MRSA). For Gram-negative bacteria, ACH-702 showed exceptional potency against Haemophilus influenzae, Moraxella catarrhalis, and a Neisseria sp. but was less active against members of the Enterobacteriaceae. Good antibacterial activity was also evident against several anaerobes as well as Legionella pneumophila and Mycoplasma pneumoniae. Excellent bactericidal activity was observed for ACH-702 against several bacterial pathogens in time-kill assays, and postantibiotic effects (PAEs) of >1 h were evident with both laboratory and clinical strains of staphylococci at 10 × MIC and similar in most cases to those observed for moxifloxacin at the same MIC multiple. In vivo efficacy was demonstrated against S. aureus with murine sepsis and thigh infection models, with decreases in the number of CFU/thigh equal to or greater than those observed after vancomycin treatment. Macromolecular synthesis assays showed specific dose-dependent inhibition of DNA replication in staphylococci, and biochemical analyses indicated potent dual inhibition of two essential DNA replication enzymes: DNA gyrase and topoisomerase IV. Additional biological data in support of an effective dual targeting mechanism of action include the following: low MIC values (≤0.25 μg/ml) against staphylococcal strains with single mutations in both gyrA and grlA (parC), retention of good antibacterial activity (MICs of ≤0.5 μg/ml) against staphylococcal strains with two mutations in both gyrA and grlA, and low frequencies for the selection of higher-level resistance (<10⁻¹⁰). These promising initial data support further study of isothiazoloquinolones as potential clinical candidates.

  20. Subversion of actin dynamics by EspM effectors of attaching and effacing bacterial pathogens.

    Science.gov (United States)

    Arbeloa, Ana; Bulgin, Richard R; MacKenzie, Georgina; Shaw, Robert K; Pallen, Mark J; Crepin, Valerie F; Berger, Cedric N; Frankel, Gad

    2008-07-01

    Rho GTPases are common targets of bacterial toxins and type III secretion system effectors. IpgB1 and IpgB2 of Shigella and Map of enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli were recently grouped together on the basis that they share a conserved WxxxE motif. In this study, we characterized six WxxxE effectors from attaching and effacing pathogens: TrcA and EspM1 of EPEC strain B171, EspM1 and EspM2 of EHEC strain Sakai and EspM2 and EspM3 of Citrobacter rodentium. We show that EspM2 triggers formation of global parallel stress fibres, TrcA and EspM1 induce formation of localized parallel stress fibres and EspM3 triggers formation of localized radial stress fibres. Using EspM2 and EspM3 as model effectors, we report that while substituting the conserved Trp with Ala abolished activity, conservative Trp to Tyr or Glu to Asp substitutions did not affect stress-fibre formation. We show, using dominant negative constructs and chemical inhibitors, that the activity of EspM2 and EspM3 is RhoA and ROCK-dependent. Using Rhotekin pull-downs, we have shown that EspM2 and EspM3 activate RhoA; translocation of EspM2 and EspM3 triggered phosphorylation of cofilin. These results suggest that the EspM effectors modulate actin dynamics by activating the RhoA signalling pathway.

  1. Endophytic Streptomyces spp. as Biocontrol Agents of Rice Bacterial Leaf Blight Pathogen (Xanthomonas oryzae pv. oryzae

    Directory of Open Access Journals (Sweden)

    RATIH DEWI HASTUTI

    2012-12-01

    Full Text Available Xanthomonas oryzae pv. oryzae (Xoo, a causal agent of bacterial leaf blight (BLB, is one of the most important pathogens of rice. The effectiveness of ten Streptomyces spp. isolates in suppressing Xoo disease was assessed in planta and in vitro. In planta experiments were carried out in a greenhouse and arranged in a randomized completely block design (RCBD with three replications. Twenty treatments were tested which included plants inoculated with both Streptomyces spp. and Xoo, and plants inoculated with only Streptomyces spp. Plants inoculated with Xoo and sprayed with a chemical bactericide, and plants inoculated with only Xoo served as positive controls, whereas plants not inoculated with either Streptomyces spp. or Xoo were used as negative controls. The results showed that the effect of endophytic Streptomyces spp. on BLB disease expressed as area under disease progress curve (AUDPC was not significantly different to that on control plants (P > 0.05. However, plants inoculated with endophytic Streptomyces spp. were significantly taller and produced higher tiller number than control plants (P < 0.05. Streptomyces spp. isolate AB131-1 gave the highest plant height. In vitro studies on biocontrol mechanisms of selected Streptomyces spp. isolates showed that isolate LBR02 gave the highest inhibition activity on Xoo growth, followed by AB131-1 and AB131-2. Two isolates (AB131-1 and LBR02 were able to produce chitinase, phosphatase, and siderophore which included biocontrol characteristics. Morphological and colonization studies under SEM and light microscopy confirmed that the three isolates were endophytic Streptomyces spp. from different species. These studies found that the paddy plant which was inoculated with endophytic Streptomyces spp. AB131-1 and infected by Xoo could increase the height of plant and number of tillers.

  2. Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators

    Science.gov (United States)

    Haack, S.K.; Duris, J.W.; Fogarty, L.R.; Kolpin, D.W.; Focazio, M.J.; Furlong, E.T.; Meyer, M.T.

    2009-01-01

    The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes. Genes tested included esp (indicating human-pathogenic ENT) and nine genes associated with various animal sources of shiga-toxin-producing EC (STEC). Fecal pollution was indicated by genes and/or chemicals for 14 of the 18 tested samples, with little relation to FIB standards. Of 13 samples with of wastewater treatment plant effluent occurred in six, veterinary antibiotics were detected in three, and stx1 or stx2 genes (indicating varying animal sources of STEC) were detected in eight. Only the EC eaeA gene was positively correlated with FIB concentrations. Human-source fecal pollution was indicated by the esp gene and the human pharmaceutical carbamazepine in one of the nine samples that met all FIB recreational water quality standards. Escherichia coli rfbO157 and stx2c genes, which are typically associated with cattle sources and are of potential human health significance, were detected in one sample in the absence of tested chemicals. Chemical and gene-based indicators of fecal contamination may be present even when FIB standards are met, and some may, unlike FIB, indicate potential sources. Application of multiple water quality indicators with variable environmental persistence and fate may yield greater confidence in fecal pollution assessment and may inform remediation decisions. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  3. High Frequency of Enteric Protozoan, Viral, and Bacterial Potential Pathogens in Community-Acquired Acute Diarrheal Episodes: Evidence Based on Results of Luminex Gastrointestinal Pathogen Panel Assay

    OpenAIRE

    Hawash, Yousry A.; Ismail, Khadiga A.; Almehmadi, Mazen

    2017-01-01

    Infectious diarrhea is endemic in most developing countries. We aimed to investigate the protozoan, viral, and bacterial causes of acute diarrhea in Taif, Saudi Arabia. A cross-sectional prospective 1-year study was conducted on 163 diarrheal patients of various ages. Stool samples were collected, 1 per patient, and tested for 3 protozoa, 3 viruses, and 9 bacteria with the Luminex Gastrointestinal Pathogen Panel. Overall, 53.4% (87/163) of samples were positives (20.8% protozoa, 19.6% viruses...

  4. In vitro antibacterial activity of venom protein isolated from sea snake Enhydrina schistosa against drugresistant human pathogenic bacterial strains

    Directory of Open Access Journals (Sweden)

    Palani Damotharan

    2015-06-01

    Full Text Available Objective: To evaluate the antibacterial activity of sea snake (Enhydrina schistosa venom protein against drug-resistant human pathogenic bacterial strains. Methods: The venom was collected by milking process from the live specimens of sea snake are using capillary tubes or glass plates. Venom was purified by ion exchange chromatography and it was tested for in-vitro antibacterial activity against 10 drug-resistant human pathogenic bacterial strains using the standard disc diffusion method. Results: The notable antibacterial activity was observed at 150 µg/mL concentration of purified venom and gave its minimum inhibitory concentrations values exhibited between 200-100 µg/mL against all the tested bacterial strains. The maximum zone of inhibition was observed at 16.4 mm against Salmonella boydii and the minimum activity was observed at 7.5 mm against Pseudomonas aeruginosa. After the sodium-dodecyl-sulfate-polyacrylamide gel electrophoresis there were a clear single band was detected in the gel that corresponding to purified venom protein molecular weight of 44 kDa. Conclusions: These results suggested that the sea snake venom might be a feasible source for searching potential antibiotics agents against human pathogenic diseases.

  5. Large scale genomic analysis shows no evidence for pathogen adaptation between the blood and cerebrospinal fluid niches during bacterial meningitis

    Science.gov (United States)

    Lees, John A.; Kremer, Philip H. C.; Manso, Ana S.; Croucher, Nicholas J.; Ferwerda, Bart; Serón, Mercedes Valls; Oggioni, Marco R.; Parkhill, Julian; Brouwer, Matthijs C.; van der Ende, Arie; van de Beek, Diederik

    2017-01-01

    Recent studies have provided evidence for rapid pathogen genome diversification, some of which could potentially affect the course of disease. We have previously described such variation seen between isolates infecting the blood and cerebrospinal fluid (CSF) of a single patient during a case of bacterial meningitis. Here, we performed whole-genome sequencing of paired isolates from the blood and CSF of 869 meningitis patients to determine whether such variation frequently occurs between these two niches in cases of bacterial meningitis. Using a combination of reference-free variant calling approaches, we show that no genetic adaptation occurs in either invaded niche during bacterial meningitis for two major pathogen species, Streptococcus pneumoniae and Neisseria meningitidis. This study therefore shows that the bacteria capable of causing meningitis are already able to do this upon entering the blood, and no further sequence change is necessary to cross the blood–brain barrier. Our findings place the focus back on bacterial evolution between nasopharyngeal carriage and invasion, or diversity of the host, as likely mechanisms for determining invasiveness. PMID:28348877

  6. Development of a panel of recombinase polymerase amplification assays for detection of common bacterial urinary tract infection pathogens.

    Science.gov (United States)

    Raja, B; Goux, H J; Marapadaga, A; Rajagopalan, S; Kourentzi, K; Willson, R C

    2017-08-01

    To develop and evaluate the performance of a panel of isothermal real-time recombinase polymerase amplification (RPA) assays for detection of common bacterial urinary tract infection (UTI) pathogens. The panel included RPAs for Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterococcus faecalis. All five RPAs required reaction times of under 12 min to reach their lower limit of detection of 100 genomes per reaction or less, and did not cross-react with high concentrations of nontarget bacterial genomic DNA. In a 50-sample retrospective clinical study, the five-RPA assay panel was found to have a specificity of 100% (95% CI, 78-100%) and a sensitivity of 89% (95% CI, 75-96%) for UTI detection. The analytical and clinical validity of RPA for the rapid and sensitive detection of common UTI pathogens was established. Rapid identification of the causative pathogens of UTIs can be valuable in preventing serious complications by helping avoid the empirical treatment necessitated by traditional urine culture's 48-72-h turnaround time. The routine and widespread use of RPA to supplement or replace culture-based methods could profoundly impact UTI management and the emergence of multidrug-resistant pathogens. © 2017 The Society for Applied Microbiology.

  7. Galleria mellonella as an in vivo model for assessing the protective activity of probiotics against gastrointestinal bacterial pathogens.

    Science.gov (United States)

    Scalfaro, Concetta; Iacobino, Angelo; Nardis, Chiara; Franciosa, Giovanna

    2017-04-01

    The antagonistic activity against gastrointestinal bacterial pathogens is an important property of probiotic bacteria and a desirable feature for pre-selection of novel strains with probiotic potential. Pre-screening of candidate probiotics for antibacterial activity should be based on in vitro and in vivo tests. This study investigated whether the protective activity of probiotic bacteria against gastrointestinal bacterial pathogens can be evaluated using Galleria mellonella larvae as an in vivo model. Larvae were pre-inoculated with either of two widely used probiotic bacteria, Lactobacillus rhamnosus GG or Clostridium butyricum Miyairi 588, and then challenged with Salmonella enterica Typhimurium, enteropathogenic Escherichia coli or Listeria monocytogenes. Survival rates increased in the probiotic pretreated larvae compared with control larvae inoculated with pathogens only. The hemocyte density increased as well in the probiotic pretreated larvae, indicating that both probiotics induce an immune response in the larvae. The antibacterial activity of probiotics against the pathogens was also assayed by an in vitro agar spot test: results were partially consistent with those obtained by the G. mellonella protection assay. The results obtained, as a whole, suggest that G. mellonella larvae are a potentially useful in vivo model that can complement in vitro assays for pre-screening of candidate probiotics. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Antibiotic resistance among bacterial pathogens in Central Africa: a review of the published literature between 1955 and 2008.

    Science.gov (United States)

    Vlieghe, E; Phoba, M F; Tamfun, J J Muyembe; Jacobs, J

    2009-10-01

    A systematic review of the published literature on bacterial resistance in Central Africa between 1955 and 2008 was performed. Eighty-three publications from seven countries were retrieved, the majority presenting data on enteric and other gram-negative pathogens. Despite methodological limitations in many studies, alarming resistance rates are noted in nearly all pathogens. Of special concern are multidrug resistance in Shigella and Salmonella spp. and the emergence of meticillin-resistant Staphylococcus aureus, high-level penicillin-resistant Streptococcus pneumoniae and extended-spectrum beta-lactamases among gram-negative pathogens. These findings make clear that the Central African region shares the worldwide trend of increasing antimicrobial resistance and is in urgent need of sound surveillance based on competent and affordable microbiology to provide clear data on antimicrobial resistance. These data could enable redaction of local treatment guidelines and fuel national and regional policies to contain antimicrobial resistance.

  9. Immunity induced shortly after DNA vaccination of rainbow trout against rhabdoviruses protects against heterologous virus but not against bacterial pathogens

    DEFF Research Database (Denmark)

    Lorenzen, Niels; Lorenzen, Ellen; Einer-Jensen, Katja

    2002-01-01

    It was recently reported that DNA vaccination of rainbow trout fingerlings against viral hemorrhagic septicaemia virus (VHSV) induced protection within 8 days after intramuscular injection of plasmid DNA. In order to analyse the specificity of this early immunity, fish were vaccinated with plasmid...... DNA encoding the VHSV or the infectious haematopoietic necrosis virus (IHNV) glycoprotein genes and later challenged with homologous or heterologous pathogens. Challenge experiments revealed that immunity established shortly after vaccination was cross-protective between the two viral pathogens...... whereas no increased survival was found upon challenge with bacterial pathogens. Within two months after vaccination, the cross-protection disappeared while the specific immunity to homologous virus remained high. The early immunity induced by the DNA vaccines thus appeared to involve short-lived non...

  10. Filtration effects of zebra mussels on pathogens and total bacterial burden in the Odra Lagoon (South Baltic).

    Science.gov (United States)

    Daeschlein, G; Fenske, C; Scholz, S; Dahlke, S; Jünger, M; Kramer, A

    2015-01-01

    As a result of their mode of filter feeding, zebra mussels (Dreissena polymorpha Pall.) have been observed to purify natural water bodies and in vitro. Therefore, the possibility of using zebra mussels for water purification was investigated in a slightly brackish water body of a large lagoon. In this study, water samples were taken above, near and at distance from zebra mussel beds (MB) in the Odra Lagoon in North East Germany. Near typical bacterial species like Aeromonas spp. pathogenic bacteria with potential relation to hospital wastewater pollution (Burkholderia cepacia, Staphylococcus aureus, Weeksella spp.) were detected. There were no correlations found between either total bacteria or pathogens and distance to MB and no antimicrobial effect of the mussels could be deduced. For bioremediation in larger water bodies like lagoons, natural zebra MB do not seem to play a major antimicrobial role and the effect of artificial mussel grids especially against hospital pathogens should be investigated.

  11. Profiling the extended phenotype of plant pathogens: Challenges in Bacterial Molecular Plant Pathology.

    Science.gov (United States)

    Preston, Gail M

    2017-04-01

    One of the most fundamental questions in plant pathology is what determines whether a pathogen grows within a plant? This question is frequently studied in terms of the role of elicitors and pathogenicity factors in the triggering or overcoming of host defences. However, this focus fails to address the basic question of how the environment in host tissues acts to support or restrict pathogen growth. Efforts to understand this aspect of host-pathogen interactions are commonly confounded by several issues, including the complexity of the plant environment, the artificial nature of many experimental infection systems and the fact that the physiological properties of a pathogen growing in association with a plant can be very different from the properties of the pathogen in culture. It is also important to recognize that the phenotype and evolution of pathogen and host are inextricably linked through their interactions, such that the environment experienced by a pathogen within a host, and its phenotype within the host, is a product of both its interaction with its host and its evolutionary history, including its co-evolution with host plants. As the phenotypic properties of a pathogen within a host cannot be defined in isolation from the host, it may be appropriate to think of pathogens as having an 'extended phenotype' that is the product of their genotype, host interactions and population structure within the host environment. This article reflects on the challenge of defining and studying this extended phenotype, in relation to the questions posed below, and considers how knowledge of the phenotype of pathogens in the host environment could be used to improve disease control. What determines whether a pathogen grows within a plant? What aspects of pathogen biology should be considered in describing the extended phenotype of a pathogen within a host? How can we study the extended phenotype in ways that provide insights into the phenotypic properties of pathogens

  12. Reação em campo à murcha bacteriana de cultivares de tomate em Roraima Bacterial wilt resistance in tomato cultivars in Roraima, Brazil

    Directory of Open Access Journals (Sweden)

    Hyanameyka E de Lima

    2010-06-01

    .The bacterial wilt caused by Ralstonia solanacearum is the most important bacterial disease of tomato in the Brazilian North Region. The objectives of this study were to evaluate (1 the resistance level of ten tomato cultivars; (2 the progress of bacterial wilt in these genotypes in order to know the disease behavior in different stages of development of the crop, and (3 determine the critical time to disease development in these cultivars, in Roraima. The experiment was carried out in a field naturally infested with biovar 1 of R. solanacearum, during two years. The area was infested by cultivating susceptible tomato plants to bacterial wilt. The cvs. Majestade, Nemonetta, Carmen, Liliane, Santa Clara, Sensação, San Vito, Gaúcho Melhorado, Hector and Laura were cultivated in the infested field. Six disease incidence evaluations were done in seven plants with irreversible wilt and/or death during the crop cycle. The following variables were determined: area under the disease progress curve (AUPDC and the progress rate (r, mean incidence (Y50, maximum incidence (Ymax and the final incidence of the disease. The values of AUDPC and the variable r to 'Majestade' were the lowest, although the level of resistance shown by this cultivar was not very high. Therefore, 'Majestade' is recommended for planting in the State of Roraima, especially considering the high prices of tomatoes, which are purchased from other regions in the country. However, only the level of resistance of 'Majestade' is not sufficient for disease control, being necessary other control measures.

  13. Differential Attachment of Salmonella enterica and Enterohemorrhagic Escherichia coli to Alfalfa, Fenugreek, Lettuce, and Tomato Seeds.

    Science.gov (United States)

    Cui, Yue; Walcott, Ronald; Chen, Jinru

    2017-04-01

    Vegetable seeds have the potential to disseminate and transmit foodborne bacterial pathogens. This study was undertaken to assess the abilities of selected Salmonella and enterohemorrhagic Escherichia coli (EHEC) strains to attach to fungicide-treated versus untreated, and intact versus mechanically damaged, seeds of alfalfa, fenugreek, lettuce, and tomato. Surface-sanitized seeds (2 g) were exposed to four individual strains of Salmonella or EHEC at 20°C for 5 h. Contaminated seeds were rinsed twice, each with 10 ml of sterilized water, before being soaked overnight in 5 ml of phosphate-buffered saline at 4°C. The seeds were then vortexed vigorously for 1 min, and pathogen populations in seed rinse water and soaking buffer were determined using a standard plate count assay. In general, the Salmonella cells had higher attachment ratios than the EHEC cells. Lettuce seeds by unit weight had the highest numbers of attached Salmonella or EHEC cells, followed by tomato, alfalfa, and fenugreek seeds. In contrast, individual fenugreek seeds had more attached pathogen cells, followed by lettuce, alfalfa, and tomato seeds. Significantly more Salmonella and EHEC cells attached to mechanically damaged seeds than to intact seeds ( P EHEC cells were recovered from untreated than fungicide-treated seeds ( P 0.05), with a few exceptions. This study fills gaps in the current body of literature and helps explain bacterial interactions with vegetable seeds with differing surface characteristics. IMPORTANCE Vegetable seeds, specifically sprout seeds, have the potential to disseminate and transmit foodborne bacterial pathogens. This study investigated the interaction between two important bacterial pathogens, i.e., Salmonella and EHEC, and vegetable seeds with differing surface characteristics. This research helps understand whether seed surface structure, integrity, and fungicide treatment affect the interaction between bacterial cells and vegetable seeds. Copyright © 2017

  14. Frontiers for research on the ecology of plant-pathogenic bacteria: fundamentals for sustainability: Challenges in Bacterial Molecular Plant Pathology.

    Science.gov (United States)

    Morris, Cindy E; Barny, Marie-Anne; Berge, Odile; Kinkel, Linda L; Lacroix, Christelle

    2017-02-01

    Methods to ensure the health of crops owe their efficacy to the extent to which we understand the ecology and biology of environmental microorganisms and the conditions under which their interactions with plants lead to losses in crop quality or yield. However, in the pursuit of this knowledge, notions of the ecology of plant-pathogenic microorganisms have been reduced to a plant-centric and agro-centric focus. With increasing global change, i.e. changes that encompass not only climate, but also biodiversity, the geographical distribution of biomes, human demographic and socio-economic adaptations and land use, new plant health problems will emerge via a range of processes influenced by these changes. Hence, knowledge of the ecology of plant pathogens will play an increasingly important role in the anticipation and response to disease emergence. Here, we present our opinion on the major challenges facing the study of the ecology of plant-pathogenic bacteria. We argue that the discovery of markedly novel insights into the ecology of plant-pathogenic bacteria is most likely to happen within a framework of more extensive scales of space, time and biotic interactions than those that currently guide much of the research on these bacteria. This will set a context that is more propitious for the discovery of unsuspected drivers of the survival and diversification of plant-pathogenic bacteria and of the factors most critical for disease emergence, and will set the foundation for new approaches to the sustainable management of plant health. We describe the contextual background of, justification for and specific research questions with regard to the following challenges: Development of terminology to describe plant-bacterial relationships in terms of bacterial fitness. Definition of the full scope of the environments in which plant-pathogenic bacteria reside or survive. Delineation of pertinent phylogenetic contours of plant-pathogenic bacteria and naming of strains

  15. Factor H-IgG Chimeric Proteins as a Therapeutic Approach against the Gram-Positive Bacterial Pathogen Streptococcus pyogenes.

    Science.gov (United States)

    Blom, Anna M; Magda, Michal; Kohl, Lisa; Shaughnessy, Jutamas; Lambris, John D; Ram, Sanjay; Ermert, David

    2017-12-01

    Bacteria can cause life-threatening infections, such as pneumonia, meningitis, or sepsis. Antibiotic therapy is a mainstay of treatment, although antimicrobial resistance has drastically increased over the years. Unfortunately, safe and effective vaccines against most pathogens have not yet been approved, and thus developing alternative treatments is important. We analyzed the efficiency of factor H (FH)6-7/Fc, a novel antibacterial immunotherapeutic protein against the Gram-positive bacterium Streptococcus pyogenes This protein is composed of two domains of complement inhibitor human FH (FH complement control protein modules 6 and 7) that bind to S. pyogenes , linked to the Fc region of IgG (FH6-7/Fc). FH6-7/Fc has previously been shown to enhance complement-dependent killing of, and facilitate bacterial clearance in, animal models of the Gram-negative pathogens Haemophilus influenzae and Neisseria meningitidis We hypothesized that activation of complement by FH6-7/Fc on the surface of Gram-positive bacteria such as S. pyogenes will enable professional phagocytes to eliminate the pathogen. We found that FH6-7/Fc alleviated S. pyogenes- induced sepsis in a transgenic mouse model expressing human FH ( S. pyogenes binds FH in a human-specific manner). Furthermore, FH6-7/Fc, which binds to protein H and selected M proteins, displaced FH from the bacterial surface, enhanced alternative pathway activation, and reduced bacterial blood burden by opsonophagocytosis in a C3-dependent manner in an ex vivo human whole-blood model. In conclusion, FH-Fc chimeric proteins could serve as adjunctive treatments against multidrug-resistant bacterial infections. Copyright © 2017 by The American Association of Immunologists, Inc.

  16. The Effect of Antibiotic Exposure and Specimen Volume on the Detection of Bacterial Pathogens in Children With Pneumonia.

    Science.gov (United States)

    Driscoll, Amanda J; Deloria Knoll, Maria; Hammitt, Laura L; Baggett, Henry C; Brooks, W Abdullah; Feikin, Daniel R; Kotloff, Karen L; Levine, Orin S; Madhi, Shabir A; O'Brien, Katherine L; Scott, J Anthony G; Thea, Donald M; Howie, Stephen R C; Adrian, Peter V; Ahmed, Dilruba; DeLuca, Andrea N; Ebruke, Bernard E; Gitahi, Caroline; Higdon, Melissa M; Kaewpan, Anek; Karani, Angela; Karron, Ruth A; Mazumder, Razib; McLellan, Jessica; Moore, David P; Mwananyanda, Lawrence; Park, Daniel E; Prosperi, Christine; Rhodes, Julia; Saifullah, Md; Seidenberg, Phil; Sow, Samba O; Tamboura, Boubou; Zeger, Scott L; Murdoch, David R

    2017-06-15

    Antibiotic exposure and specimen volume are known to affect pathogen detection by culture. Here we assess their effects on bacterial pathogen detection by both culture and polymerase chain reaction (PCR) in children. PERCH (Pneumonia Etiology Research for Child Health) is a case-control study of pneumonia in children aged 1-59 months investigating pathogens in blood, nasopharyngeal/oropharyngeal (NP/OP) swabs, and induced sputum by culture and PCR. Antibiotic exposure was ascertained by serum bioassay, and for cases, by a record of antibiotic treatment prior to specimen collection. Inoculated blood culture bottles were weighed to estimate volume. Antibiotic exposure ranged by specimen type from 43.5% to 81.7% in 4223 cases and was detected in 2.3% of 4863 controls. Antibiotics were associated with a 45% reduction in blood culture yield and approximately 20% reduction in yield from induced sputum culture. Reduction in yield of Streptococcus pneumoniae from NP culture was approximately 30% in cases and approximately 32% in controls. Several bacteria had significant but marginal reductions (by 5%-7%) in detection by PCR in NP/OP swabs from both cases and controls, with the exception of S. pneumoniae in exposed controls, which was detected 25% less frequently compared to nonexposed controls. Bacterial detection in induced sputum by PCR decreased 7% for exposed compared to nonexposed cases. For every additional 1 mL of blood culture specimen collected, microbial yield increased 0.51% (95% confidence interval, 0.47%-0.54%), from 2% when volume was ≤1 mL to approximately 6% for ≥3 mL. Antibiotic exposure and blood culture volume affect detection of bacterial pathogens in children with pneumonia and should be accounted for in studies of etiology and in clinical management. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  17. To Eat and to Be Eaten: Mutual Metabolic Adaptations of Immune Cells and Intracellular Bacterial Pathogens upon Infection

    Science.gov (United States)

    Eisenreich, Wolfgang; Rudel, Thomas; Heesemann, Jürgen; Goebel, Werner

    2017-01-01

    Intracellular bacterial pathogens (IBPs) invade and replicate in different cell types including immune cells, in particular of the innate immune system (IIS) during infection in the acute phase. However, immune cells primarily function as essential players in the highly effective and integrated host defense systems comprising the IIS and the adaptive immune system (AIS), which cooperatively protect the host against invading microbes including IBPs. As countermeasures, the bacterial pathogens (and in particular the IBPs) have developed strategies to evade or reprogram the IIS at various steps. The intracellular replication capacity and the anti-immune defense responses of the IBP's as well as the specific antimicrobial responses of the immune cells of the innate and the AIS depend on specific metabolic programs of the IBPs and their host cells. The metabolic programs of the immune cells supporting or counteracting replication of the IBPs appear to be mutually exclusive. Indeed, recent studies show that upon interaction of naïve, metabolically quiescent immune cells with IBPs, different metabolic activation processes occur which may result in the provision of a survival and replication niche for the pathogen or its eradication. It is therefore likely that within a possible host cell population subsets exist that are metabolically programmed for pro- or anti-microbial conditions. These metabolic programs may be triggered by the interactions between different bacterial agonistic components and host cell receptors. In this review, we summarize the current status in the field and discuss metabolic adaptation processes within immune cells of the IIS and the IBPs that support or restrict the intracellular replication of the pathogens. PMID:28752080

  18. Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

    Science.gov (United States)

    Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

    2003-01-01

    The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

  19. Transmission dynamics of gram-negative bacterial pathogens in the anesthesia work area.

    Science.gov (United States)

    Loftus, Randy W; Brown, Jeremiah R; Patel, Hetal M; Koff, Matthew D; Jensen, Jens T; Reddy, Sundara; Ruoff, Kathryn L; Heard, Stephen O; Dodds, Thomas M; Beach, Michael L; Yeager, Mark P

    2015-04-01

    Gram-negative organisms are a major health care concern with increasing prevalence of infection and community spread. Our primary aim was to characterize the transmission dynamics of frequently encountered gram-negative bacteria in the anesthesia work area environment (AWE). Our secondary aim was to examine links between these transmission events and 30-day postoperative health care-associated infections (HCAIs). Gram-negative isolates obtained from the AWE (patient nasopharynx and axilla, anesthesia provider hands, and the adjustable pressure-limiting valve and agent dial of the anesthesia machine) at 3 major academic medical centers were identified as possible intraoperative bacterial transmission events by class of pathogen, temporal association, and phenotypic analysis (analytical profile indexing). The top 5 frequently encountered genera were subjected to antibiotic disk diffusion sensitivity to identify epidemiologically related transmission events. Complete multivariable logistic regression analysis and binomial tests of proportion were then used to examine the relative contributions of reservoirs of origin and within- and between-case modes of transmission, respectively, to epidemiologically related transmission events. Analyses were conducted with and without the inclusion of duplicate transmission events of the same genera occurring in a given study unit (first and second case of the day in each operating room observed) to examine the potential effect of statistical dependency. Transmitted isolates were compared by pulsed-field gel electrophoresis to disease-causing bacteria for 30-day postoperative HCAIs. The top 5 frequently encountered gram-negative genera included Acinetobacter, Pseudomonas, Brevundimonas, Enterobacter, and Moraxella that together accounted for 81% (767/945) of possible transmission events. For all isolates, 22% (167/767) of possible transmission events were identified by antibiotic susceptibility patterns as epidemiologically related

  20. Conserved host-pathogen PPIs. Globally conserved inter-species bacterial PPIs based conserved host-pathogen interactome derived novel target in C. pseudotuberculosis, C. diphtheriae, M. tuberculosis, C. ulcerans, Y. pestis, and E. coli targeted by Piper betel compounds

    DEFF Research Database (Denmark)

    Barh, Debmalya; Gupta, Krishnakant; Jain, Neha

    2013-01-01

    -species bacterial PPI using conserved proteins in multiple pathogens (Y. pestis, M. tuberculosis, C. diphtheriae, C. ulcerans, E. coli, and all four Cp strains) and E. Coli based experimentally validated PPI data. Furthermore, the interacting proteins in the common conserved inter-species bacterial PPI were used...

  1. Prevalence of swine viral and bacterial pathogens in rodents and stray cats captured around pig farms in Korea.

    Science.gov (United States)

    Truong, Quang Lam; Seo, Tae Won; Yoon, Byung-Il; Kim, Hyeon-Cheol; Han, Jeong Hee; Hahn, Tae-Wook

    2013-12-30

    In 2008, 102 rodents and 24 stray cats from the areas around 9 pig farms in northeast South Korea were used to determine the prevalence of the following selected swine pathogens: ten viral pathogens [porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), rotavirus, classical swine fever virus (CSFV), porcine circovirus type 2 (PCV2), encephalomyocarditis virus (EMCV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine parvovirus (PPV), pseudorabies virus (PRV) and Japanese encephalitis virus (JEV)] and four bacterial pathogens (Brucella, Leptospira, Salmonella and Lawsonia intracellularis). In total, 1,260 tissue samples from 102 rodents and 24 stray cats were examined by specific PCR and RT-PCR assays, including tissue samples of the brain, tonsils, lungs, heart, liver, kidneys, spleen, small intestine, large intestine and mesenteric lymph nodes. The percentages of PCR-positive rodents for the porcine pathogens were as follows: 63.7% for Leptospira, 39.2% for Brucella, 6.8% for Salmonella, 15.7% for L. intracellularis, 14.7% for PCV2 and 3.9% for EMCV. The percentages of PCR-positive stray cats for the swine pathogens were as follows: 62.5% for Leptospira, 25% for Brucella, 12.5% for Salmonella, 12.5% for L. intracellularis and 4.2% for PEDV. These results may be helpful for developing control measures to prevent the spread of infectious diseases of pigs.

  2. Structured literature review of responses of cattle to viral and bacterial pathogens causing bovine respiratory disease complex.

    Science.gov (United States)

    Grissett, G P; White, B J; Larson, R L

    2015-01-01

    Bovine respiratory disease (BRD) is an economically important disease of cattle and continues to be an intensely studied topic. However, literature summarizing the time between pathogen exposure and clinical signs, shedding, and seroconversion is minimal. A structured literature review of the published literature was performed to determine cattle responses (time from pathogen exposure to clinical signs, shedding, and seroconversion) in challenge models using common BRD viral and bacterial pathogens. After review a descriptive analysis of published studies using common BRD pathogen challenge studies was performed. Inclusion criteria were single pathogen challenge studies with no treatment or vaccination evaluating outcomes of interest: clinical signs, shedding, and seroconversion. Pathogens of interest included: bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BHV-1), parainfluenza-3 virus, bovine respiratory syncytial virus, Mannheimia haemolytica, Mycoplasma bovis, Pastuerella multocida, and Histophilus somni. Thirty-five studies and 64 trials were included for analysis. The median days to the resolution of clinical signs after BVDV challenge was 15 and shedding was not detected on day 12 postchallenge. Resolution of BHV-1 shedding resolved on day 12 and clinical signs on day 12 postchallenge. Bovine respiratory syncytial virus ceased shedding on day 9 and median time to resolution of clinical signs was on day 12 postchallenge. M. haemolytica resolved clinical signs 8 days postchallenge. This literature review and descriptive analysis can serve as a resource to assist in designing challenge model studies and potentially aid in estimation of duration of clinical disease and shedding after natural pathogen exposure. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  3. Isolation, pathogenicity and characterization of a novel bacterial pathogen Streptococcus uberis from diseased mandarin fish Siniperca chuatsi.

    Science.gov (United States)

    Luo, Xia; Fu, Xiaozhe; Liao, Guoli; Chang, Ouqin; Huang, Zhibin; Li, Ningqiu

    2017-06-01

    In recent years, mandarin fish had a high mortality rate associated with abnormal swimming, exophthalmia, corneal opacity and eye hemorrhage on a fish farm located at Foshan city, Guangdong province, China. Three isolates of Gram-positive, chain-forming cocci were recovered from moribund fish, and designated as SS131025-1, SS131025-2, and SS131025-3. These isolates were identified as Streptococcus uberis according to their morphologic and physio-biochemical characteristics as well as phylogenetic analysis based on their 16S rRNA and GapC gene sequences. The pathogenicity of S. uberis to mandarin fish was determined by challenge experiments. Results of artificial challenge showed S. uberis infected healthy mandarin fish and lead to death by eyeball injection or immersion route, and the LD 50 of SS131025-1 with eyeball injection was 2.0 × 10 6.42  CFU per fish. Moreover extracellular product (ECP) of the isolated S.uberis induced CPB cell apoptosis and cause death of mandarin fish. In addition, these S. uberis strains could also infect tilapia, but not grass carp and crucian carp, and grew in brain-heart infusion broth with an optimal temperature of 37 °C, pH of 7.0, and salinity of 0%. Antibiotic sensitivity testing indicated that these isolates were susceptible to rifampicin and furazolidone but resistant to 20 kinds of antibiotics. Histopathologically, infection with S. uberis could cause serious pathological changes in brain tissues such as vacuoles in matrix, swollen mitochondria with lysis of cristae and disintegration, and lots of coccus was observed both under electron and light microscope. These results shed some light on the pathogenicity of the isolates and how to prevent and control S. uberis infection in mandarin fish. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Enhancing disease resistance against microbial pathogens by expression of Et-AMPs in Arabidopsis plants

    OpenAIRE

    Amran, Ammar Youssef

    2010-01-01

    The aim of the study was to detect the potency of the novel insect antimicrobial peptides Et-AMP1 and Et-AMP2 derived from drone fly Eristalis tenax to engineer disease resistance in the model plant Arabidopsis thaliana against the fungal pathogen grey mold Botrytis cinerea and the bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000. For the first antimicrobial peptide (Et-AMP1), a protocol for the production of recombinant protein in E. coli expression system was ...

  5. Bacterial Pathogens in Ixodid Ticks from a Piedmont County in North Carolina: Prevalence of Rickettsial Organisms

    Science.gov (United States)

    2010-01-01

    scapularis-Pathogen prevalence-Rickettsia-Rickettsia amblyommii. Introduction TICK-BORNE ILLNESSES (TBis) are zoonoses involving pathogens...white- tailed deer, and emergence of Amblyomma americanum- associated zoonoses in the United States. CTMI 2007; 315: 289-324. Papin, JF, Vahrson, W

  6. Genome Sequence of the Banana Pathogen Dickeya zeae Strain MS1, Which Causes Bacterial Soft Rot.

    Science.gov (United States)

    Zhang, Jing-Xin; Lin, Bi-Run; Shen, Hui-Fang; Pu, Xiao-Ming

    2013-06-13

    We report a draft genome sequence of Dickeya zeae strain MS1, which is the causative agent of banana soft rot in China, and we show several of its specific properties compared with those of other D. zeae strains. Genome sequencing provides a tool for understanding the genomic determination of the pathogenicity and phylogeny placement of this pathogen.

  7. Genome Sequence of the Banana Pathogen Dickeya zeae Strain MS1, Which Causes Bacterial Soft Rot

    OpenAIRE

    Zhang, Jing-Xin; Lin, Bi-Run; Shen, Hui-Fang; Pu, Xiao-Ming

    2013-01-01

    We report a draft genome sequence of Dickeya zeae strain MS1, which is the causative agent of banana soft rot in China, and we show several of its specific properties compared with those of other D.?zeae strains. Genome sequencing provides a tool for understanding the genomic determination of the pathogenicity and phylogeny placement of this pathogen.

  8. Mass spectrometry-based bacterial proteomics: focus on dermatological associated microbial pathogens

    Directory of Open Access Journals (Sweden)

    Youcef eSoufi

    2016-02-01

    Full Text Available The composition of human skin acts as a natural habitat for various bacterial species that function in a commensal and symbiotic fashion. In a healthy individual, bacterial flora serves to protect the host. Under certain conditions such as minor trauma, impaired host immunity, or environmental factors, the risk of developing skin infections is increased. Although a large majority of bacterial associated skin infections are common, a portion can potentially manifest into clinically significant morbidity. For example, Gram positive species that typically reside on the skin such as Staphylococcus and Streptococcus can cause numerous epidermal (impetigo, ecthyma and dermal (cellulitis, necrotizing fasciitis, erysipelas skin infections. Moreover, the increasing incidence of bacterial antibiotic resistance represents a serious challenge to modern medicine and threatens the health care system. Therefore, it is critical to develop tools and strategies that can allow us to better elucidate the nature and mechanism of bacterial virulence. To this end, mass spectrometry (MS-based proteomics has been revolutionizing biomedical research, and has positively impacted the microbiology field. Advances in MS technologies have paved the way for numerous bacterial proteomes and their respective post translational modifications (PTMs to be accurately identified and quantified in a high throughput and robust fashion. This technological platform offers critical information with regards to signal transduction, adherence, and microbial-host interactions associated with bacterial pathogenesis. This mini-review serves to highlight the current progress proteomics has contributed towards the understanding of bacteria that are associated with skin related diseases, infections, and antibiotic resistance.

  9. Morphological and molecular identification of Colletotrichum acutatum from tomato fruit

    OpenAIRE

    Živković Svetlana; Stojanović Saša; Ivanović Žarko; Trkulja Nenad; Dolovac Nenad; Aleksić Goran; Balaž Jelica

    2010-01-01

    Colletotrichum gloeosporioides, Colletotrichum acutatum, Colletotrichum coccodes, and Colletotrichum dematium are the four main species of Colletotrichum that cause tomato anthracnose. In Serbia, the occurrence of anthracnose on tomato fruit has been recorded during the last several years. Typical fruit symptoms include dark, sunken, and circular lesion with orange conidial masses. Pathogen isolates were obtained from a diseased tomato fruits, on PDA medium...

  10. Isolation and characterization of gut bacterial proteases involved in inducing pathogenicity of Bacillus thuringiensis toxin in cotton bollworm, Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Visweshwar Regode

    2016-10-01

    Full Text Available Bacillus thuringiensis (Bt toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation towards pro-Cry1Ac. Among twelve gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2 and IVS3 were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2 and IVS3 isolates were purified to 11.90-, 15.50- and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40 oC. Maximum inhibition of total proteolytic activity was exerted by PMSF followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65 and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity towards H. armigera. The gut bacterial isolates IVS1, IVS2 and IVS3 showed homology with Bacillus thuringiensis (CP003763.1, Vibrio fischeri (CP000020.2 and Escherichia coli (CP011342.1, respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of Bt protoxin and play a major role in inducing pathogenicity of Bt toxins in H. armigera.

  11. Mondini dysplasia with recurrent bacterial meningitis caused by three different pathogens.

    Science.gov (United States)

    Shikano, Hiroaki; Ohnishi, Hidenori; Fukutomi, Hisashi; Ito, Kimiko; Morimoto, Masahiro; Teramoto, Takahide; Aoki, Mitsuhiro; Nishihori, Takezumi; Akeda, Yukihiro; Oishi, Kazunori; Fukao, Toshiyuki

    2015-12-01

    Mondini dysplasia is rare, but has an important association with recurrent bacterial meningitis. We herein describe the case of a 3-year-old girl with unilateral sensorineural hearing loss who presented with three independent episodes of bacterial meningitis within 8 months. Temporal bone computed tomography indicated the characteristic features of Mondini dysplasia in the right inner ear. This was treated by surgical closure of the inner ear defect via oval window and additional vaccination was administered. Appropriate vaccination might prevent the recurrent bacterial meningitis associated with Mondini dysplasia. © 2015 Japan Pediatric Society.

  12. Parallel evolution of a type IV secretion system in radiating lineages of the host-restricted bacterial pathogen Bartonella.

    Science.gov (United States)

    Engel, Philipp; Salzburger, Walter; Liesch, Marius; Chang, Chao-Chin; Maruyama, Soichi; Lanz, Christa; Calteau, Alexandra; Lajus, Aurélie; Médigue, Claudine; Schuster, Stephan C; Dehio, Christoph

    2011-02-10

    Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS), and thereby translocated Bartonella effector proteins (Beps), evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial pathogens

  13. Parallel evolution of a type IV secretion system in radiating lineages of the host-restricted bacterial pathogen Bartonella.

    Directory of Open Access Journals (Sweden)

    Philipp Engel

    2011-02-01

    Full Text Available Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS, and thereby translocated Bartonella effector proteins (Beps, evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial

  14. Cytotoxic chromosomal targeting by CRISPR/Cas systems can reshape bacterial genomes and expel or remodel pathogenicity islands.

    Science.gov (United States)

    Vercoe, Reuben B; Chang, James T; Dy, Ron L; Taylor, Corinda; Gristwood, Tamzin; Clulow, James S; Richter, Corinna; Przybilski, Rita; Pitman, Andrew R; Fineran, Peter C

    2013-04-01

    In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs) and their associated (Cas) proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2) involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas-mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM) beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA-targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity.

  15. Cytotoxic Chromosomal Targeting by CRISPR/Cas Systems Can Reshape Bacterial Genomes and Expel or Remodel Pathogenicity Islands

    Science.gov (United States)

    Vercoe, Reuben B.; Chang, James T.; Dy, Ron L.; Taylor, Corinda; Gristwood, Tamzin; Clulow, James S.; Richter, Corinna; Przybilski, Rita; Pitman, Andrew R.; Fineran, Peter C.

    2013-01-01

    In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs) and their associated (Cas) proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2) involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas–mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM) beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA–targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity. PMID:23637624

  16. Quantitative, multiplexed detection of bacterial pathogens: DNA and protein applications of the Luminex LabMAP system.

    Science.gov (United States)

    Dunbar, Sherry A; Vander Zee, Coe A; Oliver, Kerry G; Karem, Kevin L; Jacobson, James W

    2003-05-01

    Escherichia coli, Salmonella, Listeria monocytogenes and Campylobacter jejuni are bacterial pathogens commonly implicated in foodborne illnesses. Generally used detection methods (i.e., culture, biochemical testing, ELISA and nucleic acid amplification) can be laborious, time-consuming and require multiple tests to detect all of the pathogens. Our objective was to develop rapid assays to simultaneously detect these four organisms through the presence of antigen or DNA using the Luminex LabMAP system. For nucleic acid detection, organism-specific capture probes corresponding to the 23S ribosomal RNA gene (rrl) were coupled covalently to LabMAP microspheres. Target molecules included synthetic complementary oligonucleotides and genomic DNA isolated from ATCC type strains or other well-characterized strains of each organism. Universal PCR primers were designed to amplify variable regions of bacterial 23S ribosomal DNA, yielding biotinylated amplicons of 86 to 109 bp in length. Varying quantities of targets were hybridized to the combined microsphere sets, labeled with streptavidin-R-phycoerythrin and analyzed on the Luminex(100) system. Results of nucleic acid detection assays, obtained in 30 to 40 min following amplification, correctly and specifically identified each bacterial species with a detection sensitivity of 10(3) to 10(5) genome copies. Capture-sandwich immunoassays were developed with organism-specific antibodies coupled to different microsphere sets. Microspheres were incubated with organism-specific standards and reactivity was assessed with biotinylated detection antibodies and streptavidin-R-phycoerythrin. In the immunoassays, microsphere-associated fluorescence was organism concentration dependent with detectable response at detection of pathogens. The practical significance of this multiplexing approach would be to provide more timely, economical and comprehensive information than is available with conventional isolation and identification

  17. Cytotoxic chromosomal targeting by CRISPR/Cas systems can reshape bacterial genomes and expel or remodel pathogenicity islands.

    Directory of Open Access Journals (Sweden)

    Reuben B Vercoe

    2013-04-01

    Full Text Available In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs and their associated (Cas proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2 involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas-mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA-targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity.

  18. Nanoparticle targeting of Gram-positive and Gram-negative bacteria for magnetic-based separations of bacterial pathogens

    Science.gov (United States)

    Lu, Hoang D.; Yang, Shirley S.; Wilson, Brian K.; McManus, Simon A.; Chen, Christopher V. H.-H.; Prud'homme, Robert K.

    2017-04-01

    Antimicrobial resistance is a healthcare problem of increasing significance, and there is increasing interest in developing new tools to address bacterial infections. Bacteria-targeting nanoparticles hold promise to improve drug efficacy, compliance, and safety. In addition, nanoparticles can also be used for novel applications, such as bacterial imaging or bioseperations. We here present the use of a scalable block-copolymer-directed self-assembly process, Flash NanoPrecipitation, to form zinc(II)-bis(dipicolylamine) modified nanoparticles that bind to both Gram-positive and Gram-negative bacteria with specificity. Particles have tunable surface ligand densities that change particle avidity and binding efficacy. A variety of materials can be encapsulated into the core of the particles, such as optical dyes or iron oxide colloids, to produce imageable and magnetically active bacterial targeting constructs. As a proof-of-concept, these particles are used to bind and separate bacteria from solution in a magnetic column. Magnetic manipulation and separation would translate to a platform for pathogen identification or removal. These magnetic and targeted nanoparticles enable new methods to address bacterial infections.

  19. Microfluidic quantification of multiple enteric and opportunistic bacterial pathogens in roof-harvested rainwater tank samples.

    Science.gov (United States)

    Ahmed, Warish; Zhang, Qian; Ishii, Satoshi; Hamilton, Kerry; Haas, Charles

    2018-01-30

    Potable and non-potable uses of roof-harvested rainwater (RHRW) are increasing due to water shortages. To protect human health risks, it is important to identify and quantify disease-causing pathogens in RHRW so that appropriate treatment options can be implemented. We used a microfluidic quantitative PCR (MFQPCR) system for the quantitative detection of a wide array of fecal indicator bacteria (FIB) and pathogens in RHRW tank samples along with culturable FIB and conventional qPCR analysis of selected pathogens. Among the nine pathogenic bacteria and their associated genes tested with the MFQPCR, 4.86 and 2.77% samples were positive for Legionella pneumophila and Shigella spp., respectively. The remaining seven pathogens were absent. MFQPCR and conventional qPCR results showed good agreement. Therefore, direct pathogen quantification by MFQPCR systems may be advantageous for circumstances where a thorough microbial analysis is required to assess the public health risks from multiple pathogens that occur simultaneously in the target water source.

  20. Genome-wide analysis of bacterial determinants of plant growth promotion and induced systemic resistance by Pseudomonas fluorescens

    NARCIS (Netherlands)

    Cheng, Xu; Etalo, Desalegn W.; van de Mortel, Judith E.; Dekkers, Ester; Nguyen, Linh; Medema, Marnix H; Raaijmakers, Jos M.

    2017-01-01

    Pseudomonas fluorescens strain SS101 (Pf.SS101) promotes growth of Arabidopsis thaliana, enhances greening and lateral root formation, and induces systemic resistance (ISR) against the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Here, targeted and untargeted approaches were adopted to

  1. The tomato leucine-rich repeat receptor-like kinases SlSERK3A and SlSERK3B have overlapping functions in bacterial and nematode innate immunity.

    Directory of Open Access Journals (Sweden)

    Hsuan-Chieh Peng

    Full Text Available The Somatic Embryogenesis Receptor Kinase 3 (SERK3/Brassinosteroid (BR Insensitive 1-Associated Kinase 1 (BAK1 is required for pattern-triggered immunity (PTI in Arabidopsis thaliana and Nicotiana benthamiana. Tomato (Solanum lycopersicum has three SlSERK members. Two of them exhibit particularly high levels of sequence similarity to AtSERK3 and, therefore, were named SlSERK3A and SlSERK3B. To characterize a role for SlSERK3A and SlSERK3B in defense, we suppressed each gene individually or co-silenced both using virus-induced gene silencing (VIGS in the tomato cv. Moneymaker. Co-silencing SlSERK3A and SlSERK3B resulted in spontaneous necrotic lesions and reduced sensitivity to exogenous BR treatment. Silencing either SlSERK3A or SlSERK3B resulted in enhanced susceptibility to root knot-nematode and to non-pathogenic Pseudomonas syringae pv. tomato (Pst DC3000 hrcC indicating that both SlSERK3s are positive regulators of defense. Interestingly, silencing SlSERK3B, but not SlSERK3A, resulted in enhanced susceptibility to the pathogenic strain Pst DC3000 indicating distinct roles for these two SlSERK3 paralogs. SlSERK3A and SlSERK3B are active kinases, localized to the plasma membrane, and interact in vivo with the Flagellin Sensing 2 receptor in a flg22-dependent manner. Complementation of the Atserk3/bak1-4 mutant with either SlSERK3A or SlSERK3B partially rescued the mutant phenotype. Thus, SlSERK3A and SlSERK3B are likely to constitute tomato orthologs of BAK1.

  2. Bacteriophage Resistance Mechanisms in the Fish Pathogen Flavobacterium psychrophilum: Linking Genomic Mutations to Changes in Bacterial Virulence Factors

    DEFF Research Database (Denmark)

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Dalsgaard, Inger

    2015-01-01

    requires overcoming the selection for phage resistance in the bacterial populations. Here, we analyzed resistance mechanisms in F. psychrophilum after phage exposure using whole-genome sequencing of the ancestral phage-sensitive strain 950106-1/1 and six phage-resistant isolates. The phage-resistant...... resistance and the genetic modifications were supported by direct measurements of bacteriophage adsorption rates, biofilm formation, and secretion of extracellular enzymes, which were all impaired in the resistant strains, probably due to superficial structural changes. The clustered regularly interspaced...... were associated with a number of derived effects on the physiological properties of the pathogen, including reduced virulence under in vitro conditions. Consequently, phage-driven physiological changes associated with resistance may have implications for the impact of the pathogen in aquaculture...

  3. Daily variations in pathogenic bacterial populations in a monsoon influenced tropical environment

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A; Naik, S.D.; Gaonkar, C.C.

    Changing climatic conditions have influenced the monsoon pattern in recent years. Variations in bacterial population in one such tropical environment were observed everyday over two years and point out intra and inter annual changes driven...

  4. Pseudomonas fluorescens filamentous hemagglutinin, an iron-regulated protein, is an important virulence factor that modulates bacterial pathogenicity

    Directory of Open Access Journals (Sweden)

    Yuan-yuan Sun

    2016-08-01

    Full Text Available Pseudomonas fluorescens is a common bacterial pathogen to a wide range of aquaculture animals including various species of fish. In this study, we employed proteomic analysis and identified filamentous hemagglutinin (FHA as an iron-responsive protein secreted by TSS, a pathogenic P. fluorescens isolate. In vitro study showed that compared to the wild type, the fha mutant TSSfha (i exhibited a largely similar vegetative growth profile but significantly retarded in the ability of biofilm growth and producing extracellular matrix, (ii displayed no apparent flagella and motility, (iii was defective in the attachment to host cells and unable to form self-aggregation, (iv displayed markedly reduced capacity of hemagglutination and surviving in host serum. In vivo infection analysis revealed that TSSfha was significantly attenuated in the ability of dissemination in fish tissues and inducing host mortality, and that antibody blocking of the natural FHA produced by the wild type TSS impaired the infectivity of the pathogen. Furthermore, when introduced into turbot as a subunit vaccine, recombinant FHA elicited a significant protection against lethal TSS challenge. Taken together, these results indicate for the first time that P. fluorescens FHA is a key virulence factor essential to multiple biological processes associated with pathogenicity.

  5. The application of loop-mediated isothermal amplification (LAMP) in food testing for bacterial pathogens and fungal contaminants.

    Science.gov (United States)

    Niessen, Ludwig; Luo, Jie; Denschlag, Carla; Vogel, Rudi F

    2013-12-01

    Bacterial pathogens and toxicants, parasites as well as mycotoxin producing fungi are the major biotic factors influencing the safety of food. Moreover, viral infections and prions may be present as quasi biotic challenging factors. A vast array of culture dependent analytical methods and protocols for food safety testing has been developed during the past decades. Presently, protocols involving molecular biological techniques such as PCR-based nucleic acid amplification and hybridization have become available for many of the known pathogens with their major advantages being rapidness, high sensitivity and specificity. However, this type of assays is still quite labor- and cost intensive and mostly cannot be operated directly in the field. Recently, loop-mediated isothermal amplification (LAMP) of DNA has emerged as an alternative to the use of PCR-based methods not only in food safety testing but also in a wide array of application. Its advantages over PCR-based techniques are even shorter reaction time, no need for specific equipment, high sensitivity and specificity as well as comparably low susceptibility to inhibitors present in sample materials which enables detection of the pathogens in sample materials even without time consuming sample preparation. The present article presents a critical review of the application of LAMP-based methods and their usefulness in detecting and identifying food borne bacterial pathogens and toxicants as well as mycotoxin producing food borne fungi as compared to other methods. Moreover does it elaborate on new developments in the design and automation of LAMP-based assays and their implications for the future developments of food testing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Tomato Preserves.

    Science.gov (United States)

    Stevens, Wendy Tessman

    1996-01-01

    Describes a project in which students selected seeds from two heirloom varieties of tomatoes, sowed the seeds, harvested the tomatoes, and fermented the seeds. Details are provided for each step of the project and the school address is included so that other students can begin similar projects. (DDR)

  7. Emergence of a resistance breaking TSWV strain in tomato in California

    Science.gov (United States)

    Tomato spotted wilt virus (TSWV) is a highly destructive pathogen of tomato in the central valley of California. During the 2016 tomato growing season, unusually early and severe symptoms of TSWV occurred in fields of TSWV-resistant fresh market tomato cultivars. Disease incidences of 50-80% were ob...

  8. A study of bacterial pathogens and antibiotic susceptibility patterns in chronic suppurative otitis media.

    Science.gov (United States)

    Mofatteh, M R; Shahabian Moghaddam, F; Yousefi, M; Namaei, M H

    2018-01-01

    To assess the frequency of bacterial agents in chronic suppurative otitis media and the antibiotic susceptibility patterns of isolates among patients. A total of 185 patients clinically diagnosed with chronic suppurative otitis media were interviewed and middle-ear effusion samples were collected using sterile swabs. All bacterial isolates were identified by conventional microbiological methods. Antibiotic susceptibility patterns of the isolates were determined by Kirby-Bauer disc diffusion. Staphylococci spp. (64.9 per cent) were the most prevalent bacteria isolated, followed by Klebsiella spp. (12.9 per cent) and Pseudomonas aeruginosa (10.3 per cent). The most effective antibiotic for treatment of bacterial chronic suppurative otitis media was ciprofloxacin. Statistical analysis showed no significant difference in bacterial infestations among chronic suppurative otitis media patients and the antimicrobial susceptibility patterns of the bacterial isolates based on gender and age (p > 0.05). Our findings highlight the importance of a continuous and periodic evaluation of the bacteriological profile and antibiotic susceptibility patterns in chronic suppurative otitis media patients for efficacious treatment of the infection.

  9. High Frequency of Enteric Protozoan, Viral, and Bacterial Potential Pathogens in Community-Acquired Acute Diarrheal Episodes: Evidence Based on Results of Luminex Gastrointestinal Pathogen Panel Assay.

    Science.gov (United States)

    Hawash, Yousry A; Ismail, Khadiga A; Almehmadi, Mazen

    2017-10-01

    Infectious diarrhea is endemic in most developing countries. We aimed to investigate the protozoan, viral, and bacterial causes of acute diarrhea in Taif, Saudi Arabia. A cross-sectional prospective 1-year study was conducted on 163 diarrheal patients of various ages. Stool samples were collected, 1 per patient, and tested for 3 protozoa, 3 viruses, and 9 bacteria with the Luminex Gastrointestinal Pathogen Panel. Overall, 53.4% (87/163) of samples were positives (20.8% protozoa, 19.6% viruses, 2.8% bacteria, and 9.8% mixed). Rotavirus (19.6%), Giardia duodenalis (16.5%), and Cryptosporidium spp. (8.5%) were the mostly detected pathogens. Adenovirus 40/41 (4.2%), Salmonella (3%), Shiga toxin-producing Escherichia coli (3%), and Entamoeba histolytica (2.4%) were also detected. Norovirus GI/II, Vibrio cholerae, Yersinia enterocolitica, and Clostridium difficile toxin A/B were not detected in any patients. All pathogens were involved in coinfections except E. histolytica. Giardia (5.5%) and rotavirus (3%) were the most commonly detected in co-infections. Enterotoxigenic E. coli (2.4%), Campylobacter spp. (2.4%), E. coli 0157 (1.8%), and Shigella spp. (1.2%) were detected in patients only as co-infections. Infections were more in children 0-4 years, less in adults 40 years, with statistically significant differences in risk across age groups observed with rotavirus (P<0.001), Giardia (P=0.006), and Cryptosporidium (P=0.036) infections. Lastly, infections were not significantly more in the spring. This report demonstrates the high burden of various enteropathogens in the setting. Further studies are needed to define the impact of these findings on the clinical course of the disease.

  10. Pattern of Bacterial Pathogens and Their Susceptibility Isolated from Surgical Site Infections at Selected Referral Hospitals, Addis Ababa, Ethiopia

    Directory of Open Access Journals (Sweden)

    Walelign Dessie

    2016-01-01

    Full Text Available Background. The emergence of multidrug resistant bacterial pathogens in hospitals is becoming a challenge for surgeons to treat hospital acquired infections. Objective. To determine bacterial pathogens and drug susceptibility isolated from surgical site infections at St. Paul Specialized Hospital Millennium Medical College and Yekatit 12 Referral Hospital Medical College, Addis Ababa, Ethiopia. Methods. A cross-sectional study was conducted between October 2013 and March 2014 on 107 surgical site infected patients. Wound specimens were collected using sterile cotton swab and processed as per standard operative procedures in appropriate culture media; and susceptibility testing was done using Kirby-Bauer disc diffusion technique. The data were analyzed by using SPSS version 20. Result. From a total of 107 swabs collected, 90 (84.1% were culture positive and 104 organisms were isolated. E. coli (24 (23.1% was the most common organism isolated followed by multidrug resistant Acinetobacter species (23 (22.1%. More than 58 (75% of the Gram negative isolates showed multiple antibiotic resistance (resistance ≥ 5 drugs. Pan-antibiotic resistance was noted among 8 (34.8% Acinetobacter species and 3 (12.5% E. coli. This calls for abstinence from antibiotic abuse. Conclusion. Gram negative bacteria were the most important isolates accounting for 76 (73.1%. Ampicillin, amoxicillin, penicillin, cephazoline, and tetracycline showed resistance while gentamicin and ciprofloxacin were relatively effective antimicrobials.

  11. Bacterial inclusion bodies as potential synthetic devices for pathogen recognition and a therapeutic substance release.

    Science.gov (United States)

    Talafová, Klaudia; Hrabárová, Eva; Chorvát, Dušan; Nahálka, Jozef

    2013-02-07

    Adhesins of pathogens recognise the glycans on the host cell and mediate adherence. They are also crucial for determining the tissue preferences of pathogens. Currently, glyco-nanomaterials provide potential tool for antimicrobial therapy. We demonstrate that properly glyco-tailored inclusion bodies can specifically bind pathogen adhesins and release therapeutic substances. In this paper, we describe the preparation of tailored inclusion bodies via the conjugation of indicator protein aggregated to form inclusion bodies with soluble proteins. Whereas the indicator protein represents a remedy, the soluble proteins play a role in pathogen recognition. For conjugation, glutaraldehyde was used as linker. The treatment of conjugates with polar lysine, which was used to inactivate the residual glutaraldehyde, inhibited unwanted hydrophobic interactions between inclusion bodies. The tailored inclusion bodies specifically interacted with the SabA adhesin from Helicobacter pylori aggregated to form inclusion bodies that were bound to the sialic acids decorating the surface of human erythrocytes. We also tested the release of indicator proteins from the inclusion bodies using sortase A and Ssp DNAB intein self-cleaving modules, respectively. Sortase A released proteins in a relatively short period of time, whereas the intein cleavage took several weeks. The tailored inclusion bodies are promising "nanopills" for biomedical applications. They are able to specifically target the pathogen, while a self-cleaving module releases a soluble remedy. Various self-cleaving modules can be enabled to achieve the diverse pace of remedy release.

  12. Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part I: Overview, vaccines for enteric viruses and Vibrio cholerae.

    Science.gov (United States)

    O'Ryan, Miguel; Vidal, Roberto; del Canto, Felipe; Salazar, Juan Carlos; Montero, David

    2015-01-01

    Efforts to develop vaccines for prevention of acute diarrhea have been going on for more than 40 y with partial success. The myriad of pathogens, more than 20, that have been identified as a cause of acute diarrhea throughout the years pose a significant challenge for selecting and further developing the most relevant vaccine candidates. Based on pathogen distribution as identified in epidemiological studies performed mostly in low-resource countries, rotavirus, Cryptosporidium, Shigella, diarrheogenic E. coli and V. cholerae are predominant, and thus the main targets for vaccine development and implementation. Vaccination against norovirus is most relevant in middle/high-income countries and possibly in resource-deprived countries, pending a more precise characterization of disease impact. Only a few licensed vaccines are currently available, of which rotavirus vaccines have been the most outstanding in demonstrating a significant impact in a short time period. This is a comprehensive review, divided into 2 articles, of nearly 50 vaccine candidates against the most relevant viral and bacterial pathogens that cause acute gastroenteritis. In order to facilitate reading, sections for each pathogen are organized as follows: i) a discussion of the main epidemiological and pathogenic features; and ii) a discussion of vaccines based on their stage of development, moving from current licensed vaccines to vaccines in advanced stage of development (in phase IIb or III trials) to vaccines in early stages of clinical development (in phase I/II) or preclinical development in animal models. In this first article we discuss rotavirus, norovirus and Vibrio cholerae. In the following article we will discuss Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic), and Campylobacter jejuni.

  13. Antibacterial and Antioxidant Activities of Liquidambar Orientalis Mill. Various Extracts Against Bacterial Pathogens Causing Mastitis

    Directory of Open Access Journals (Sweden)

    Gülten Ökmen

    2017-08-01

    Full Text Available Antibiotic resistance is being constantly developed worldwide. Coagulase Negative Staphylococci (CNS and Staphylococcus aureus are common causes of bovine subclinical mastitis. Bioactive compound of medicinal plants shows anti-microbial, anti-mutagenic and anti-oxidant effects. The anti-bacterial and anti-oxidant activities of Liquidambar orientalis (L. orientalis extracts on subclinical mastitis causing bacteria in cows have not been reported to date. The aim of the present study was to examine anti-bacterial and anti-oxidant effects of L. orientalis leaf extracts on S. aureus and CNS isolated from cows with subclinical mastitis symptoms. In this study, 3.2 mg/mL minimum inhibitory concentration (MIC of ethanol extracts of L. orientalis has shown to be a most potent anti-bacterial and anti-oxidant for all isolated bacterial species from mastitis cows. In this study, it was investigated anti-bacterial and anti-oxidant potentials of acetone, methanol and ethanol extracts of the L. orientalis. The acetone extract showed maximum inhibition zone against S. aureus numbered 17 (12 mm. In addition to anti-bacterial properties, anti-oxidant activity of L. orientalis extract was examined by ABTS [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid] free radical assay. Trolox was used as a positive control anti-oxidant. Ethanol extract exhibited a strong anti-oxidant activity like Trolox anti-oxidant which was effective at 2.58 mM concentration. Bioactive compounds of sweet gum may be useful to screening mastitis causing bacteria for clinical applications.

  14. Detection of the sour-rot pathogen Geotrichum candidum in tomato fruit and juice by using a highly specific monoclonal antibody-based ELISA.

    Science.gov (United States)

    Thornton, Christopher R; Slaughter, David C; Davis, R Michael

    2010-10-15

    Geotrichum candidum is a common soil-borne fungus that causes sour-rot of tomatoes, citrus fruits and vegetables, and is a major contaminant on tomato processing equipment. The aim of this work was to produce a monoclonal antibody and diagnostic assay for its detection in tomato fruit and juice. Using hybridoma technology, a cell line (FE10) was generated that produced a monoclonal antibody belonging to the immunoglobulin class M (IgM) that was specific to G. candidum and the closely related teleomorphic species Galactomyces geotrichum and anamorphic species Geotrichum europaeum and Geotrichum pseudocandidum in the G. geotrichum/G. candidum complex. The MAb did not cross-react with a wide range of unrelated fungi, including some likely to be encountered during crop production and processing. The MAb binds to an immunodominant high molecular mass (> 200 kDa) extracellular polysaccharide antigen that is present on the surface of arthroconidia and hyphae of G. candidum. The MAb was used in a highly specific enzyme-linked immunosorbent assay (ELISA) to accurately detect the fungus in infected tomato fruit and juice. Specificity of the ELISA was confirmed by sequencing of the internally transcribed spacer (ITS) 1-5.8S-ITS2 rRNA-encoding regions of fungi isolated from naturally-infected tomatoes. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Xanthomonas perforans Colonization Influences Salmonella enterica in the Tomato Phyllosphere

    Science.gov (United States)

    Potnis, Neha; Soto-Arias, José Pablo; Cowles, Kimberly N.; van Bruggen, Ariena H. C.; Jones, Jeffrey B.

    2014-01-01

    Salmonella enterica rarely grows on healthy, undamaged plants, but its persistence is influenced by bacterial plant pathogens. The interactions between S. enterica, Xanthomonas perforans (a tomato bacterial spot pathogen), and tomato were characterized. We observed that virulent X. perforans, which establishes disease by suppressing pathogen-associated molecular pattern (PAMP)-triggered immunity that leads to effector-triggered susceptibility, created a conducive environment for persistence of S. enterica in the tomato phyllosphere, while activation of effector-triggered immunity by avirulent X. perforans resulted in a dramatic reduction in S. enterica populations. S. enterica populations persisted at ∼10 times higher levels in leaves coinoculated with virulent X. perforans than in those where S. enterica was applied alone. In contrast, S. enterica populations were ∼5 times smaller in leaves coinoculated with avirulent X. perforans than in leaves inoculated with S. enterica alone. Coinoculation with virulent X. perforans increased S. enterica aggregate formation; however, S. enterica was not found in mixed aggregates with X. perforans. Increased aggregate formation by S. enterica may serve as the mechanism of persistence on leaves cocolonized by virulent X. perforans. S. enterica association with stomata was altered by X. perforans; however, it did not result in appreciable populations of S. enterica in the apoplast even in the presence of large virulent X. perforans populations. Gene-for-gene resistance against X. perforans successively restricted S. enterica populations. Given the effect of this interaction, breeding for disease-resistant cultivars may be an effective strategy to limit both plant disease and S. enterica populations and, consequently, human illness. PMID:24632252

  16. Foodborne Bacterial Pathogens in Retail Prepacked Ready-to-Eat Mixed Ingredient Salads.

    Science.gov (United States)

    Söderqvist, Karin; Thisted Lambertz, Susanne; Vågsholm, Ivar; Boqvist, Sofia

    2016-06-01

    Prepacked ready-to-eat mixed ingredient salads (RTE salads) are readily available whole meals that include a variety of ingredients such as raw vegetables, cooked meat, and pasta. As part of a trend toward healthy convenience foods, RTE salads have become an increasingly popular product among consumers. However, data on the incidence of foodborne pathogens in RTE salads are scarce. In this study, the microbiological safety of 141 RTE salads containing chicken, ham, or smoked salmon was investigated. Salad samples were collected at retail and analyzed using standard methods for Listeria monocytogenes, Shiga toxin-producing Escherichia coli (STEC), pathogenic Yersinia enterocolitica, Salmonella, and Campylobacter spp.L. monocytogenes was isolated from two (1.4%) of the RTE salad samples. Seven (5.0%) of the samples were positive for the ail gene (present in all human pathogenic Y. enterocolitica isolates) and three (2.1%) of the samples were positive for the Shiga toxin genes stx1 and/or stx2. However, no strains of pathogenic Y.enterocolitica or STEC were isolated. Thus, pathogens were found or suspected in almost 1 of 10 RTE salads investigated, and pathogenic bacteria probably are present in various RTE salads from retail premises in Sweden. Because RTE salads are intended to be consumed without heat treatment, control of the ingredients and production hygiene is essential to maintain consumer safety. The recommended maximum storage temperature for RTE salads varies among countries but can be up to 8°C (e.g., in Sweden). Even during a short shelf life (3 to 5 days), storage at 8°C can enable growth of psychrotrophs such as L. monocytogenes and Y. enterocolitica. The maximum storage temperature should therefore be reduced.

  17. Body lice of homeless people reveal the presence of several emerging bacterial pathogens in northern Algeria.

    Science.gov (United States)

    Louni, Meriem; Mana, Nassima; Bitam, Idir; Dahmani, Mustapha; Parola, Philippe; Fenollar, Florence; Raoult, Didier; Mediannikov, Oleg

    2018-04-17

    Human lice, Pediculus humanus, are obligate blood-sucking parasites. Body lice, Pediculus h. humanus, occur in two divergent mitochondrial clades (A and D) each exhibiting a particular geographic distribution. Currently, the body louse is recognized as the only vector for louse-borne diseases. In this study, we aimed to study the genetic diversity of body lice collected from homeless populations in three localities of northern Algeria, and to investigate louse-borne pathogens in these lice. In this study, 524 body lice specimens were collected from 44 homeless people in three localities: Algiers, Tizi Ouzou and Boumerdès located in northern Algeria. Duplex clade specific real-time PCRs (qPCR) and Cytochrome b (cytb) mitochondrial DNA (mtDNA) analysis were performed in order to identify the mitochondrial clade. Screening of louse-borne pathogens bacteria was based on targeting specific genes for each pathogen using qPCR supplemented by sequencing. All body lice belong to clade A. Through amplification and sequencing of the cytb gene we confirmed the presence of three haplotypes: A5, A9 and A63, which is novel. The molecular investigation of the 524 body lice samples revealed the presence of four human pathogens: Bartonella quintana (13.35%), Coxiella burnetii (10.52%), Anaplasma phagocytophilum (0.76%) and Acinetobacter species (A. baumannii, A. johnsonii, A. berezeniae, A. nosocomialis and A. variabilis, in total 46.94%). To the best of our knowledge, our study is the first to show the genetic diversity and presence of several emerging pathogenic bacteria in homeless' body lice from Algeria. We also report for the first time, the presence of several species of Acinetobacter in human body lice. Our results highlight the fact that body lice may be suspected as being a much broader vector of several pathogenic agents than previously thought. Nevertheless, other studies are needed to encourage epidemiological investigations and surveys of louse-associated infections.

  18. Expression and Purification of the Main Component Contained in Camel Milk and Its Antimicrobial Activities Against Bacterial Plant Pathogens.

    Science.gov (United States)

    Tanhaeian, Abbas; Shahriari Ahmadi, Farajollah; Sekhavati, Mohammad Hadi; Mamarabadi, Mojtaba

    2018-04-04

    Lactoferrin is the most dominant protein in milk after casein. This protein plays a crucial role in many biological processes including the regulation of iron metabolism, induction and modulation of the immune system, the primary defense against microorganisms, inhibiting lipid peroxidation and presenting antimicrobial activity against various pathogens such as parasites, fungi, bacteria, and viruses. The major antimicrobial effect of lactoferrin is related to its N-terminal tail where different peptides for instance lactoferricin and lactoferrampin which are important for their antimicrobial abilities are present. The growth rate of bacterial cells in camel milk is lower than that of the cow milk due to having more antimicrobial compounds. In this study, we have fused a codon-optimized partial camel lactoferrcin and lactoferrampin DNA sequences in order to construct a fused peptide via a lysine. This chimeric 42-mer peptide consists of complete and partial amino acid sequence of camel lactoferrampin and lactoferricin, respectively. Human embryonic kidney 293 (HEK-293) cells were used for synthesizing this recombinant peptide. Finally, the antibacterial activities of this constructed peptide were investigated under in vitro condition. The result showed that, all construction, cloning and expression processes were successfully performed in HEK-293. One His-tag tail was added to the chimera in order to optimize the isolation and purification processes and also reduce the cost of production. Additionally, His-tag retained the antimicrobial activity of the chimera. The antimicrobial tests showed that the growth rate in the majority of bacterial plant pathogens, including gram negative and positive bacteria, was inhibited by recombinant chimera as the level of MIC values were evaluated between 0.39 and 25.07 μg/ml for different bacterial isolates.

  19. Intracellular Bacterial Pathogens Trigger the Formation of U Small Nuclear RNA Bodies (U Bodies) through Metabolic Stress Induction.

    Science.gov (United States)

    Tsalikis, Jessica; Tattoli, Ivan; Ling, Arthur; Sorbara, Matthew T; Croitoru, David O; Philpott, Dana J; Girardin, Stephen E

    2015-08-21

    Invasive bacterial pathogens induce an amino acid starvation (AAS) response in infected host cells that controls host defense in part by promoting autophagy. However, whether AAS has additional significant effects on the host response to intracellular bacteria remains poorly characterized. Here we showed that Shigella, Salmonella, and Listeria interfere with spliceosomal U snRNA maturation in the cytosol. Bacterial infection resulted in the rerouting of U snRNAs and their cytoplasmic escort, the survival motor neuron (SMN) complex, to processing bodies, thus forming U snRNA bodies (U bodies). This process likely contributes to the decline in the cytosolic levels of U snRNAs and of the SMN complex proteins SMN and DDX20 that we observed in infected cells. U body formation was triggered by membrane damage in infected cells and was associated with the induction of metabolic stresses, such as AAS or endoplasmic reticulum stress. Mechanistically, targeting of U snRNAs to U bodies was regulated by translation initiation inhibition and the ATF4/ATF3 pathway, and U bodies rapidly disappeared upon removal of the stress, suggesting that their accumulation represented an adaptive response to metabolic stress. Importantly, this process likely contributed to shape the host response to invasive bacteria because down-regulation of DDX20 expression using short hairpin RNA (shRNA) amplified ATF3- and NF-κB-dependent signaling. Together, these results identify a critical role for metabolic stress and invasive bacterial pathogens in U body formation and suggest that this process contributes to host defense. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Specific detection of common pathogens of acute bacterial meningitis using an internally controlled tetraplex-PCR assay.

    Science.gov (United States)

    Farahani, Hamidreza; Ghaznavi-Rad, Ehsanollah; Mondanizadeh, Mahdieh; MirabSamiee, Siamak; Khansarinejad, Behzad

    2016-08-01

    Accurate and timely diagnosis of acute bacterial meningitis is critical for antimicrobial treatment of patients. Although PCR-based methods have been widely used for the diagnosis of acute meningitis caused by bacterial pathogens, the main disadvantage of these methods is their high cost. This disadvantage has hampered the widespread use of molecular assays in many developing countries. The application of multiplex assays and "in-house" protocols are two main approaches that can reduce the overall cost of a molecular test. In the present study, an internally controlled tetraplex-PCR was developed and validated for the specific detection of Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae in cerebrospinal fluid (CSF) samples. The analysis of a panel of other human pathogens showed no cross-reactivity in the assay. The analytical sensitivity of the in-house assay was 792.3 copies/ml, when all three bacteria were presentin the specimens. This value was calculated as 444.5, 283.7, 127.8 copies/ml when only S. pneumoniae, N. meningitidis and H. influenzae, respectively, were present. To demonstrate the diagnostic performance of the assay, a total of 150 archival CSF samples were tested and compared with a commercial multiplex real-time PCR kit. A diagnostic sensitivity of 92.8% and a specificity of 95.1% were determined for the present tetraplex-PCR assay. The results indicate that the established method is sensitive, specific and cost-effective, and can be used particularly in situations where the high cost of commercial kits prevents the use of molecular methods for the diagnosis of bacterial meningitis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. First characterization of bacterial pathogen, Vibrio alginolyticus, for Porites andrewsi White syndrome in the South China Sea.

    Directory of Open Access Journals (Sweden)

    Xie Zhenyu

    Full Text Available White syndrome, a term for scleractinian coral disease with progressive tissue loss, is known to cause depressed growth and increased morality of coral reefs in the major oceans around the world, and the occurrence of this disease has been frequently reported in the past few decades. Investigations during April to September in both 2010 and 2011 identified widespread Porites andrewsi White syndrome (PAWS in Xisha Archipelago, South China Sea. However, the causes and etiology of PAWS have been unknown.A transmission experiment was performed on P. andrewsi in the Qilianyu Subgroup (QLY. The results showed that there was a significant (P ≤ 0.05 difference between test and control groups after 28 days if the invalid replicates were excluded. Rates of tissue loss ranged from 0.90-10.76 cm(2 d(-1 with a mean of 5.40 ± 3.34 cm(2 d(-1 (mean ± SD. Bacterial strains were isolated from the PAWS corals at the disease outbreak sites in QLY of the Xisha Archipelago, South China Sea, and included in laboratory-based infection trials to satisfy Koch's postulates for establishing causality. Following exposure to bacterial concentrations of 10(5 cells mL(-1, the infected colonies exhibited similar signs to those observed in the field. Using phylogenetic 16S rRNA gene analysis, classical phenotypic trait comparison, Biolog automatic identification system, MALDI-TOF mass spectrometry and MALDI Biotyper method, two pathogenic strains were identified as Vibrio alginolyticus .This is the first report of V. alginolyticus as a pathogenic agent of PAWS in the South China Sea. Our results point out an urgent need to develop sensitive detection methods for V. alginolyticus virulence strains and robust diagnostics for coral disease caused by this and Vibrio pathogenic bacterium in the South China Sea.

  2. Multidrug Efflux Pumps from Enterobacteriaceae, Vibrio cholerae and Staphylococcus aureus Bacterial Food Pathogens

    Science.gov (United States)

    Andersen, Jody L.; He, Gui-Xin; Kakarla, Prathusha; KC, Ranjana; Kumar, Sanath; Lakra, Wazir Singh; Mukherjee, Mun Mun; Ranaweera, Indrika; Shrestha, Ugina; Tran, Thuy; Varela, Manuel F.

    2015-01-01

    Foodborne illnesses caused by bacterial microorganisms are common worldwide and constitute a serious public health concern. In particular, microorganisms belonging to the Enterobacteriaceae and Vibrionaceae families of Gram-negative bacteria, and to the Staphylococcus genus of Gram-positive bacteria are important causative agents of food poisoning and infection in the gastrointestinal tract of humans. Recently, variants of these bacteria have developed resistance to medically important chemotherapeutic agents. Multidrug resistant Escherichia coli, Salmonella enterica, Vibrio cholerae, Enterobacter spp., and Staphylococcus aureus are becoming increasingly recalcitrant to clinical treatment in human patients. Of the various bacterial resistance mechanisms against antimicrobial agents, multidrug efflux pumps comprise a major cause of multiple drug resistance. These multidrug efflux pump systems reside in the biological membrane of the bacteria and actively extrude antimicrobial agents from bacterial cells. This review article summarizes the evolution of these bacterial drug efflux pump systems from a molecular biological standpoint and provides a framework for future work aimed at reducing the conditions that foster dissemination of these multidrug resistant causative agents through human populations. PMID:25635914

  3. Rapid Identification of Bacterial Pathogens of Military Interest Using Surface-Enhanced Raman Spectroscopy

    Science.gov (United States)

    2014-06-11

    wound infections. Methods: A total of sixteen bacterial isolates including: six Acinetobacter baumannii , four Staphylococcus aureus, three... Acinetobacter baumannii -calcoaceticus complex, which remains a critical cause of infection. Additionally, there has been a dramatic increase of...manufacturer’s instructions. Lysozyme treatment was used for Acinetobacter baumannii prior to cell lysis, while lysostaphin and lysozyme were used for

  4. Multidrug Efflux Pumps from Enterobacteriaceae, Vibrio cholerae and Staphylococcus aureus Bacterial Food Pathogens

    Directory of Open Access Journals (Sweden)

    Jody L. Andersen

    2015-01-01

    Full Text Available Foodborne illnesses caused by bacterial microorganisms are common worldwide and constitute a serious public health concern. In particular, microorganisms belonging to the Enterobacteriaceae and Vibrionaceae families of Gram-negative bacteria, and to the Staphylococcus genus of Gram-positive bacteria are important causative agents of food poisoning and infection in the gastrointestinal tract of humans. Recently, variants of these bacteria have developed resistance to medically important chemotherapeutic agents. Multidrug resistant Escherichia coli, Salmonella enterica, Vibrio cholerae, Enterobacter spp., and Staphylococcus aureus are becoming increasingly recalcitrant to clinical treatment in human patients. Of the various bacterial resistance mechanisms against antimicrobial agents, multidrug efflux pumps comprise a major cause of multiple drug resistance. These multidrug efflux pump systems reside in the biological membrane of the bacteria and actively extrude antimicrobial agents from bacterial cells. This review article summarizes the evolution of these bacterial drug efflux pump systems from a molecular biological standpoint and provides a framework for future work aimed at reducing the conditions that foster dissemination of these multidrug resistant causative agents through human populations.

  5. Effects of climate change on the persistence and dispersal of foodborne bacterial pathogens in the outdoor environment: A review.

    Science.gov (United States)

    Hellberg, Rosalee S; Chu, Eric

    2016-08-01

    According to the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal. Over the coming century, warming trends such as increased duration and frequency of heat waves and hot extremes are expected in some areas, as well as increased intensity of some storm systems. Climate-induced trends will impact the persistence and dispersal of foodborne pathogens in myriad ways, especially for environmentally ubiquitous and/or zoonotic microorganisms. Animal hosts of foodborne pathogens are also expected to be impacted by climate change through the introduction of increased physiological stress and, in some cases, altered geographic ranges and seasonality. This review article examines the effects of climatic factors, such as temperature, rainfall, drought and wind, on the environmental dispersal and persistence of bacterial foodborne pathogens, namely, Bacillus cereus, Brucella, Campylobacter, Clostridium, Escherichia coli, Listeria monocytogenes, Salmonella, Staphylococcus aureus, Vibrio and Yersinia enterocolitica. These relationships are then used to predict how future climatic changes will impact the activity of these microorganisms in the outdoor environment and associated food safety issues. The development of predictive models that quantify these complex relationships will also be discussed, as well as the potential impacts of climate change on transmission of foodborne disease from animal hosts.

  6. Development of non-pathogenic bacterial biofilms on the surface of stainless steel which are inhibitory to Salmonella enterica.

    Science.gov (United States)

    Kim, Yoonbin; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

    2018-02-01

    Non-pathogenic bacterial biofilms were developed on the surface of stainless steel possessing desiccation tolerance and antimicrobial activity against Salmonella enterica. Three bacteria exhibiting strong antimicrobial activities against S. enterica were isolated from various soils, foods, and food-contact surfaces. Isolates were identified as Pseudomonas extremorientalis (strain Lettuce-28), Paenibacillus peoriae (strain Lettuce-7), and Streptomyces cirratus (strain Geumsan-207). These bacteria grew rapidly and formed biofilms within 24 h on the surface of stainless steel coupons (SSCs) immersed in laboratory media (tryptic soy broth or Bennet's broth) at 25 °C. Cells in biofilms had enhanced tolerance to desiccation (exposure to 43% atmospheric relative humidity [RH]) and retained antimicrobial activity against S. enterica. Populations of S. enterica deposited on SSCs containing biofilm formed by Ps. extremorientalis strain Lettuce-28, for example, decreased by > 2.5 log CFU/coupon within 24 h at 25 °C and 43% RH, while the number of cells inoculated on SSCs lacking biofilm decreased by 1.5 log CFU/coupon. Antimicrobial activities of the three antagonistic bacteria against S. enterica persisted in desiccated biofilms. This study provides insights to developing strategies to inactivate Salmonella and perhaps other foodborne pathogens on abiotic surfaces using non-pathogenic antagonistic bacteria. Copyright © 2017. Published by Elsevier Ltd.

  7. Prevalence of plant beneficial and human pathogenic bacteria isolated from salad vegetables in India.

    Science.gov (United States)

    Nithya, Angamuthu; Babu, Subramanian

    2017-03-14

    The study aimed at enumerating, identifying and categorizing the endophytic cultivable bacterial community in selected salad vegetables (carrot, cucumber, tomato and onion). Vegetable samples were collected from markets of two vegetable hot spot growing areas, during two different crop harvest seasons. Crude and diluted vegetable extracts were plated and the population of endophytic bacteria was assessed based on morphologically distinguishable colonies. The bacterial isolates were identified by growth in selective media, biochemical tests and 16S rRNA gene sequencing. The endophytic population was found to be comparably higher in cucumber and tomato in both of the sampling locations, whereas lower in carrot and onion. Bacterial isolates belonged to 5 classes covering 46 distinct species belonging to 19 genera. Human opportunistic pathogens were predominant in carrot and onion, whereas plant beneficial bacteria dominated in cucumber and tomato. Out of the 104 isolates, 16.25% are human pathogens and 26.5% are human opportunistic pathogens. Existence of a high population of plant beneficial bacteria was found to have suppressed the population of plant and human pathogens. There is a greater potential to study the native endophytic plant beneficial bacteria for developing them as biocontrol agents against human pathogens that are harboured by plants.

  8. Antimicrobial activity of Litchi chinensis and Nephelium lappaceum aqueous seed extracts against some pathogenic bacterial strains

    OpenAIRE

    Bhat, Ramesa Shafi; Al-daihan, Sooad

    2014-01-01

    Seeds aqueous extracts from Litchi chinensis and Nephelium lappaceum were investigated for antibacterial activity by disc diffusion method and protein profile. Both seed aqueous extracts show moderate inhibition against pathogenic bacteria, both gram positive including Staphylococcus aureus, Streptococcus pyogenes, and Bacilllus subtillis and gram negative bacteria including Escherichia coli and Pseudomonas aeruginosa. Overall analysis of the antibacterial activity of tested samples revealed ...

  9. Mild processing applied to the inactivation of the main foodborne bacterial pathogens

    DEFF Research Database (Denmark)

    Barba Orellana, Francisco Jose; Koubaa, Mohamed; do Prado-Silva, Leonardo

    2017-01-01

    such as high pressure processing, ultrasounds, pulsed electric fields, UV-light, and atmospheric cold plasma may serve, in some conditions, as useful alternatives to commercial sterilization and pasteurization aiming to destroy foodborne pathogens. Each of these mild technologies has a specific mode...

  10. Bacteriophage remediation of bacterial pathogens in aquaculture: a review of the technology

    Science.gov (United States)

    Bacteriophages have been proposed as an alternative to antibiotic usage and several studies on their application in aquaculture have been reported. This review highlights progress to date on phage therapies for the following fish and shellfish diseases and associated pathogens: hemorrhagic septicem...

  11. Parasites and competitors suppress bacterial pathogen synergistically due to evolutionary trade-offs