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Sample records for pathogenic bacteria inoculated

  1. Behaviour of co-inoculated pathogenic and spoilage bacteria on poultry following several decontamination treatments.

    PubMed

    Alonso-Hernando, Alicia; Capita, Rosa; Alonso-Calleja, Carlos

    2012-10-01

    The potential of chemical decontaminants to cause harmful effects on human health is among the causes of the rejection of antimicrobial treatments for removing surface contamination from poultry carcasses in the European Union. This study was undertaken to determine whether decontaminants might give a competitive advantage to pathogenic bacteria on poultry and involve a potential risk to consumer. A total of 144 chicken legs were co-inoculated with similar concentrations of pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica serotype Enteritidis or Escherichia coli) and spoilage bacteria (Brochothrix thermosphacta or Pseudomonas fluorescens). Samples were dipped for 15min in solutions (w/v) of trisodium phosphate (12%; TSP), acidified sodium chlorite (1200ppm; ASC), citric acid (2%; CA), peroxyacids (220ppm; PA) or chlorine dioxide (50ppm; CD), or were left untreated (control). Microbiological analyses were carried out on day 0 and every 24h until day 7 of storage (at 10±1°C). The modified Gompertz equation was used as the primary model to fit observed data. TSP, ASC and CA were effective in extending the lag phase (L, ranging from 1.47±1.34days to 4.06±1.16days) and in decreasing the concentration of bacteria during the stationary phase (D, ranging from 2.46±0.51 log(10) cfu/cm(2) to 8.64±0.53 log(10) cfu/cm(2)), relative to the control samples (L values ranging from 0.59±0.38days and 2.52±2.28days, and D values ranging from 6.32±0.89 log(10) cfu/cm(2) to 9.39±0.39 log(10) cfu/cm(2), respectively). Both on untreated and on most decontaminated samples the overgrowth of spoilage bacteria among the species tested was observed throughout storage, suggesting that spoilage would occur prior to any noteworthy increase in the levels of pathogenic microorganisms. However, L. monocytogenes counts similar to, or higher than, those for spoilage bacteria were observed on samples treated with TSP, ASC or CA, suggesting that these

  2. Application of gamma irradiation for inactivation of three pathogenic bacteria inoculated into meatballs

    NASA Astrophysics Data System (ADS)

    Gumus, Tuncay; Şukru Demirci, A.; Murat Velioglu, H.; Velioglu, Serap D.; Yilmaz, Ismail; Sagdic, Osman

    2008-09-01

    In this research, the effect of gamma irradiation on the inactivation of Escherichia coli O157:H7 (ATCC 33150), Staphylococcus aureus (ATCC 2392) and Salmonella typhimurium (NRRL 4463) inoculated into Tekirdag meatballs was investigated. The meatball samples were inoculated with pathogens and irradiated at the absorbed doses of 1, 2.2, 3.2, 4.5 and 5.2 kGy. E. coli O157:H7 count in 1 kGy irradiated meatballs stored in the refrigerator for 7 days was detected to be 4 log cfu/g lower than the count in nonirradiated samples ( p<0.05). S. aureus counts were decreased to 4 log cfu/g after being exposed to irradiation at a dose of 1 kGy. Although it was ineffective on elimination of S. typhimurium, irradiation at a dose of 3.2 kGy reduced E. coli O157:H7 and S. aureus counts under detectable values in the meatballs. However, none of the test organisms were detected in the samples after irradiation with 4.5 kGy doses.

  3. A gaseous acetic acid treatment to disinfect fenugreek seeds and black pepper inoculated with pathogenic and spoilage bacteria.

    PubMed

    Nei, Daisuke; Enomoto, Katsuyoshi; Nakamura, Nobutaka

    2015-08-01

    Contamination of spices by pathogenic and/or spoilage bacteria can be deleterious to consumer's health and cause deterioration of foods, and inactivation of such bacteria is necessary for the food industry. The present study examined the effect of gaseous acetic acid treatment in reducing Escherichia coli O157:H7, Salmonella Enteritidis and Bacillus subtilis populations inoculated on fenugreek seeds and black pepper. Treatment with gaseous acetic acid at 0.3 mmol/L, 0.6 mmol/L and 4.7 mmol/L for 1-3 h significantly reduced the populations of E. coli O157:H7 and Salmonella Enteritidis on black pepper and fenugreek seeds at 55 °C (p < 0.05). The gas treatments at 4.7 mmol/L were more effective in inactivating the pathogens than the treatment at 0.3 mmol/L. An approximately 5.0 log reduction was obtained after 3 h of treatment with 4.7 mmol/L acetic acid. No significant reductions in the population of B. subtilis spores inoculated on fenugreek seeds and black pepper were obtained after the gas treatments at 0.3 mmol/L or 0.6 mmol/L (p > 0.05). However, the gas treatment at 4.7 mmol/L significantly reduced B. subtilis spores (p < 0.05), and 4.0 log CFU/g and 3.5 log CFU/g reductions on fenugreek seeds and black pepper, respectively, were obtained after 3 h of treatment. PMID:25846935

  4. A gaseous acetic acid treatment to disinfect fenugreek seeds and black pepper inoculated with pathogenic and spoilage bacteria.

    PubMed

    Nei, Daisuke; Enomoto, Katsuyoshi; Nakamura, Nobutaka

    2015-08-01

    Contamination of spices by pathogenic and/or spoilage bacteria can be deleterious to consumer's health and cause deterioration of foods, and inactivation of such bacteria is necessary for the food industry. The present study examined the effect of gaseous acetic acid treatment in reducing Escherichia coli O157:H7, Salmonella Enteritidis and Bacillus subtilis populations inoculated on fenugreek seeds and black pepper. Treatment with gaseous acetic acid at 0.3 mmol/L, 0.6 mmol/L and 4.7 mmol/L for 1-3 h significantly reduced the populations of E. coli O157:H7 and Salmonella Enteritidis on black pepper and fenugreek seeds at 55 °C (p < 0.05). The gas treatments at 4.7 mmol/L were more effective in inactivating the pathogens than the treatment at 0.3 mmol/L. An approximately 5.0 log reduction was obtained after 3 h of treatment with 4.7 mmol/L acetic acid. No significant reductions in the population of B. subtilis spores inoculated on fenugreek seeds and black pepper were obtained after the gas treatments at 0.3 mmol/L or 0.6 mmol/L (p > 0.05). However, the gas treatment at 4.7 mmol/L significantly reduced B. subtilis spores (p < 0.05), and 4.0 log CFU/g and 3.5 log CFU/g reductions on fenugreek seeds and black pepper, respectively, were obtained after 3 h of treatment.

  5. PATHOGENICITY OF BIOFILM BACTERIA

    EPA Science Inventory

    There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

  6. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria.

    PubMed

    Yasmin, Sumera; Zaka, Abha; Imran, Asma; Zahid, Muhammad Awais; Yousaf, Sumaira; Rasul, Ghulam; Arif, Muhammad; Mirza, Muhammad Sajjad

    2016-01-01

    The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB). A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo) of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1-19 mm). Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82-116 μg mL-1) and produced indole acetic acid (0.48-1.85 mg L-1) in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%), improved shoot length (31%), root length (41%) and plant dry weight (60%) as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice. PMID:27532545

  7. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria

    PubMed Central

    Zaka, Abha; Imran, Asma; Zahid, Muhammad Awais; Yousaf, Sumaira; Rasul, Ghulam; Arif, Muhammad; Mirza, Muhammad Sajjad

    2016-01-01

    The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB). A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo) of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1–19 mm). Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82–116 μg mL-1) and produced indole acetic acid (0.48–1.85 mg L-1) in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%), improved shoot length (31%), root length (41%) and plant dry weight (60%) as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice. PMID:27532545

  8. Plant growth-promoting bacteria as inoculants in agricultural soils.

    PubMed

    Souza, Rocheli de; Ambrosini, Adriana; Passaglia, Luciane M P

    2015-12-01

    Plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promotion (PGP) traits. Bacterial inoculants can contribute to increase agronomic efficiency by reducing production costs and environmental pollution, once the use of chemical fertilizers can be reduced or eliminated if the inoculants are efficient. For bacterial inoculants to obtain success in improving plant growth and productivity, several processes involved can influence the efficiency of inoculation, as for example the exudation by plant roots, the bacterial colonization in the roots, and soil health. This review presents an overview of the importance of soil-plant-microbe interactions to the development of efficient inoculants, once PGPB are extensively studied microorganisms, representing a very diverse group of easily accessible beneficial bacteria.

  9. Plant growth-promoting bacteria as inoculants in agricultural soils

    PubMed Central

    de Souza, Rocheli; Ambrosini, Adriana; Passaglia, Luciane M.P.

    2015-01-01

    Abstract Plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promotion (PGP) traits. Bacterial inoculants can contribute to increase agronomic efficiency by reducing production costs and environmental pollution, once the use of chemical fertilizers can be reduced or eliminated if the inoculants are efficient. For bacterial inoculants to obtain success in improving plant growth and productivity, several processes involved can influence the efficiency of inoculation, as for example the exudation by plant roots, the bacterial colonization in the roots, and soil health. This review presents an overview of the importance of soil-plant-microbe interactions to the development of efficient inoculants, once PGPB are extensively studied microorganisms, representing a very diverse group of easily accessible beneficial bacteria. PMID:26537605

  10. Sociomicrobiology and pathogenic bacteria

    PubMed Central

    Xavier, Joao B.

    2015-01-01

    The study of microbial pathogenesis has been primarily a reductionist science since Koch's principles. Reductionist approaches are essential to identify the causal agents of infectious disease, their molecular mechanisms of action and potential drug targets, and much of medicine's success in the treatment of infectious disease comes from this approach. But many bacterial caused diseases cannot be explained by focusing on a single bacterium. Many aspects of bacterial pathogenesis will benefit from a more holistic approach that takes into account social interaction within bacteria of the same species and between different species in consortia such as the human microbiome. I discuss recent advances in the emerging discipline of sociomicrobiology and how it provides a framework to dissect microbial interactions in single and multispecies communities without compromising mechanistic detail. The study of bacterial pathogenesis can benefit greatly from incorporating concepts from other disciplines such as social evolution theory and microbial ecology where communities, their interactions with hosts and with the environment play key roles. PMID:27337482

  11. Multistep introduction of bacteria to natural substrates at different initial inoculation doses

    NASA Astrophysics Data System (ADS)

    Kupriyanov, A. A.; Semenov, A. M.; Kunenkova, N. N.; van Bruggen, A. H. C.

    2009-09-01

    The population dynamics of the saprotrophic Pseudomonas fluorescens 32 gfp bacteria and two conventionally pathogenic enterobacteria ( Escherichia coli 0157:H7 and Salmonella enterica var. Typhimurium) were investigated in their inoculation at different doses into cattle excreta and their subsequent entering soil and plants and migration through the gastroenteric tract of invertebrates. All the introduced bacteria investigated are shown to be able to overcome ecological barriers as they migrate through the natural substrates and habitats. The introduce microorganisms maintain their high population density even at the lowest initial inoculation dose—105 CFU/g of dry matter. Plants were found to be a favorable substrate for the survival of the bacteria investigated (for enteropathogens, in particular). Enteropathogens are able to pass through the gastroenteric tract of invertebrates. Therefore, these organisms can function as incubators and carriers of enteroinfections in nature.

  12. Degradation of PAHs in soil by indigenous and inoculated bacteria

    SciTech Connect

    Aamand, J.; Bruntse, G.; Jepsen, M.; Joergensen, C.; Jensen, B.K.

    1995-12-31

    In soil heavily polluted by coal tar, the inherent mineralization of radio-labeled phenanthrene to {sup 14}CO{sub 2} was relatively slow, and a stimulation of degradation was observed by inoculation with a mixed population of PAH-degrading bacteria. A much faster inherent mineralization of phenanthrene was observed in soil slightly polluted by coal tar, and inoculation of this soil had no effect. Several phenanthrene-degrading bacteria were isolated from different soils. Two strains were further characterized as an Arthrobacter sp. and a Pseudomonas sp. In an organic medium without phenanthrene, growth rates of 0.52 h{sup {minus}1} and 0.71 h{sup {minus}1} were measured for the Arthrobacter sp. and the Pseudomonas sp., respectively. Most isolates grown in the phenanthrene-free medium, including the Arthrobacter sp., rapidly adapted to phenanthrene degradation following transfer to a phenanthrene-containing medium. In contrast, the phenanthrene-degrading capability of other strains, including the Pseudomonas sp., was lost during growth in the phenanthrene-free medium. Growth in an organic medium without phenanthrene of strains that retain the ability to degrade phenanthrene could prove to be a useful technique for production of PAH-degrading bacteria on a larger scale for soil inoculation.

  13. The dynamics of apoplast phenolics in tobacco leaves following inoculation with bacteria

    PubMed Central

    Baker, Con J.; Mock, Norton M.; Smith, Jodi M.; Aver'yanov, Andrey A.

    2015-01-01

    This study demonstrates that the accumulation of apoplastic phenolics is stimulated in planta in response to bacterial inoculation. Past studies have shown that levels of extracellular phenolics are elicited in plant cell suspensions in response to bacteria, and that tomato plants infected with viroids showed changes in apoplastic phenolics. The method described here monitored changes in apoplastic phenolics in tobacco leaves following bacterial inoculation of the same tissue. Inoculation with a saprophyte, Pseudomonas fluorescens, which does not cause visible symptoms or physical damage, was used to elicit phenolics and examine the effects of variable parameters on phenolic composition. Location of the inoculation on the leaf, position, or developmental age of the leaf on the plant, and inoculum concentration were standardized for further experiments. The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms. Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives. The latter metabolites appear to have come from the intracellular stores, which could indicate a weakening of the apoplast/symplast barrier. This unexpected aspect will require further study of intracellular phenolics. PMID:26347765

  14. Pathogenic bacteria and timing of laying

    PubMed Central

    Møller, Anders Pape; Soler, Juan J; Nielsen, Jan Tøttrup; Galván, Ismael

    2015-01-01

    Pathogenic bacteria constitute a serious threat to viability of many organisms. Because growth of most bacteria is favored by humid and warm environmental conditions, earlier reproducers in seasonal environments should suffer less from the negative consequences of pathogenic bacteria. These relationships, and the effects on reproductive success, should be particularly prominent in predators because they are frequently exposed to pathogenic microorganisms from sick prey. Here, we presented and tested this hypothesis by sampling bacteria on adult and nestling goshawks Accipiter gentilis. We predicted that early breeders and their offspring should have fewer bacteria than those reproducing later during the breeding season. Adult goshawks with a high abundance of Staphylococcus on their beak and claws were easier to capture and their laying date was delayed. Moreover, goshawks that laid their eggs later had offspring with more Staphylococcus on their beaks and claws. The strength of the association between laying date and bacterial density of nestlings was stronger during the warm spring of 2013, when nestlings suffered from a higher abundance of pathogenic bacteria. Hatching failure and fledging failure were more common in nests with a higher abundance of Staphylococcus independently of the number of years occupied, laying date, and age of the female nest owner. These findings imply that timing of reproduction may be under the influence of pathogenic bacteria. Because early breeding goshawks produce more recruits than later breeders, our results suggest a role for pathogenic bacteria in the optimal timing of reproduction. PMID:25937910

  15. HIV-Enhancing Factors Are Secreted by Reproductive Epithelia upon Inoculation with Bacterial Vaginosis-Associated Bacteria.

    PubMed

    Eade, Colleen R; Diaz, Camila; Chen, Sixue; Cole, Amy L; Cole, Alexander M

    2015-01-01

    Bacterial vaginosis is a common reproductive infection in which commensal vaginal lactobacilli are displaced by a mixed population of pathogenic bacteria. Bacterial vaginosis increases susceptibility to HIV, and it has been suggested that host innate immune responses to pathogenic bacteria contribute to enhanced infection, yet the cellular mechanisms mediating the increased HIV susceptibility remain uncharacterized. We evaluated the HIV-enhancing effects of bacterial vaginosis by inoculating endocervical epithelia with Atopobium vaginae, a bacterial vaginosis-associated bacteria, and assaying secreted factors for HIV-enhancing activity. When epithelia and A. vaginae were cocultured, we observed increased HIV-enhancing activity mediated by secreted low molecular weight factors. From this complex mixture we identified several upregulated host proteins, which functioned in combination to enhance HIV infection. These studies suggest that the host immune response to bacterial vaginosis-associated bacteria results in the release of HIV-enhancing factors. The combined activity of bacterial vaginosis-induced proteins likely mediates HIV enhancement.

  16. Functional genomics of pathogenic bacteria.

    PubMed Central

    Moxon, E R; Hood, D W; Saunders, N J; Schweda, E K H; Richards, J C

    2002-01-01

    Microbial diseases remain the commonest cause of global mortality and morbidity. Automated-DNA sequencing has revolutionized the investigation of pathogenic microbes by making the immense fund of information contained in their genomes available at reasonable cost. The challenge is how this information can be used to increase current understanding of the biology of commensal and virulence behaviour of pathogens with particular emphasis on in vivo function and novel approaches to prevention. One example of the application of whole-genome-sequence information is afforded by investigations of the pathogenic role of Haemophilus influenzae lipopolysaccharide and its candidacy as a vaccine. PMID:11839188

  17. Defense mechanisms of Solanum tuberosum L. in response to attack by plant-pathogenic bacteria.

    PubMed

    Poiatti, Vera A D; Dalmas, Fernando R; Astarita, Leandro V

    2009-01-01

    The natural resistance of plants to disease is based not only on preformed mechanisms, but also on induced mechanisms. The defense mechanisms present in resistant plants may also be found in susceptible ones. This study attempted to analyze the metabolic alterations in plants of the potato Solanum tuberosum L. cv. Agata that were inoculated with the incompatible plant-pathogenic bacteria X. axonopodis and R. solanacearum, and the compatible bacterium E. carotovora. Levels of total phenolic compounds, including the flavonoid group, and the activities of polyphenol oxidase (PPO) and peroxidase (POX) were evaluated. Bacteria compatibility was evaluated by means of infiltration of tubers. The defense response was evaluated in the leaves of the potato plants. Leaves were inoculated depending on their number and location on the stem. Multiple-leaf inoculation was carried out on basal, intermediate, and apical leaves, and single inoculations on intermediate leaves. Leaves inoculated with X. axonopodis and with R. solanacearum showed hypersensitive responses within 24 hours post-inoculation, whereas leaves inoculated with E. carotovora showed disease symptoms. Therefore, the R. solanacearum isolate used in the experiments did not exhibit virulence to this potato cultivar. Regardless of the bacterial treatments, the basal leaves showed higher PPO and POX activities and lower levels of total phenolic compounds and flavonoids, compared to the apical leaves. However, basal and intermediate leaves inoculated with R. solanacearum and X. axonopodis showed increases in total phenolic compounds and flavonoid levels. In general, multiple-leaf inoculation showed the highest levels of total phenolics and flavonoids, whereas the single inoculations resulted in the highest increase in PPO activity. The POX activity showed no significant difference between single- and multiple-leaf inoculations. Plants inoculated with E. carotovora showed no significant increase in defense mechanisms

  18. RNA-Mediated Regulation in Pathogenic Bacteria

    PubMed Central

    Caldelari, Isabelle; Chao, Yanjie; Romby, Pascale; Vogel, Jörg

    2013-01-01

    Pathogenic bacteria possess intricate regulatory networks that temporally control the production of virulence factors, and enable the bacteria to survive and proliferate after host infection. Regulatory RNAs are now recognized as important components of these networks, and their study may not only identify new approaches to combat infectious diseases but also reveal new general control mechanisms involved in bacterial gene expression. In this review, we illustrate the diversity of regulatory RNAs in bacterial pathogens, their mechanism of action, and how they can be integrated into the regulatory circuits that govern virulence-factor production. PMID:24003243

  19. The fate of potentially pathogenic bacteria in Swiss hard and semihard cheeses made from raw milk.

    PubMed

    Bachmann, H P; Spahr, U

    1995-03-01

    This study examined the ability of potentially pathogenic bacteria to grow and to survive during the manufacture and ripening of Swiss hard and semihard cheese varieties made from raw milk. The results show that hard cheeses are hygienically safe; 1 wk after fabrication, the inoculated pathogens (Aeromonas hydrophila. Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella spp., Staphylococcus aureus, and Yersinia enterocolitica) could no longer be detected. At the age of commercial ripeness, the semihard cheeses were free from the inoculated pathogens and their toxic metabolites, except for L. monocytogenes, which survived the manufacturing and ripening process.

  20. Histopathological Studies on Rabbits Infected by Bacteria Causing Infectious Keratitis in Human through Eye Inoculation

    PubMed Central

    Aldebasi, Yousef H.; Mohamed, Hala A.; Aly, Salah M.

    2014-01-01

    Aim This study aimed to investigate the pathogenic effect of bacteria causing infectious keratitis among patients through experimental study conducted on rabbits’ eyes with the aid of histopathology as eye infection is a common disease in developing countries that may complicate to loss of vision. Methodology 100 swab samples were collected from human infected eyes, at Qassim region during 2012, for the isolation of Pseudomonas aeruginosa and Staphylococcus aureus. The isolated pathogenic bacteria were tested to various antibiotics using some selected antibiotics discs through agar-well diffusion method. Then, experimental study conducted on 27 rabbits. The rabbits were divided randomly into three equal groups, each containing 9 rabbits. Rabbits of group (1) served as control group (Negative Control) and their eyes were inoculated with the buffer only. Rabbits of group (2) were inoculated through eyes with the isolated Pseudomonas aeruginosa. Rabbits of group (3) were inoculated through eyes with the isolated Staphylococcus aureus. Results Out of 100 collected swab samples from human infected eyes, Pseudomonas aeruginosa and Staphylococcus aureus were isolated with a total percentage of 25.21% and 15.65%; respectively and used in this study. Both bacterial isolates were sensitive to Gentamicin and Cefuroxime. Clinically, experimentally infected rabbits by Pseudomonas aeruginosa, revealed varying degree corneal abrasions, corneal abscess and dense corneal opacity. Histopathologically, at 3rd day post-infection (PI), the cornea revealed polymorpho-nuclear cells infiltration with loss of the outer epithelial lining. At 7th day PI, neutrophils were seen in the stroma. At 15th day PI, proliferation of fibroblasts and new vascularisation were seen in the stroma. Clinically, rabbits experimentally infected with Staphylococcus aureus, revealed corneal ulcers and focal abscesses. Histopathologically, at 3rd and 7th day PI, the cornea revealed edema and infiltration of

  1. 9 CFR 113.36 - Detection of pathogens by the chicken inoculation test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Detection of pathogens by the chicken... REQUIREMENTS Standard Procedures § 113.36 Detection of pathogens by the chicken inoculation test. The test for...,000 doses. (b) At least 25 healthy susceptible young chickens, properly identified and obtained...

  2. Colonization of plants by human pathogenic bacteria in the course of organic vegetable production

    PubMed Central

    Hofmann, Andreas; Fischer, Doreen; Hartmann, Anton; Schmid, Michael

    2014-01-01

    In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identify possible factors like bacterial species or serovariation, plant species or organic fertilizer types used, influencing the success of plant colonization by human pathogenic bacteria. Spinach and corn salad were chosen as model plants and were inoculated with different concentrations of Salmonella enterica sv. Weltevreden, Listeria monocytogenes sv. 4b and EGD-E sv. 1/2a either directly (axenic system) or via agricultural soil amended with spiked organic fertilizers (soil system). In addition to PCR- and culture-based detection methods, fluorescence in situ hybridization (FISH) was applied in order to localize bacteria on or in plant tissues. Our results demonstrate that shoots were colonized by the pathogenic bacteria at inoculation doses as low as 4 × 10 CFU/ml in the axenic system or 4 × 105 CFU/g in the soil system. In addition, plant species dependent effects were observed. Spinach was colonized more often and at lower inoculation doses compared to corn salad. Differential colonization sites on roots, depending on the plant species could be detected using FISH-CLSM analysis. Furthermore, the transfer of pathogenic bacteria to plants via organic fertilizers was observed more often and at lower initial inoculation doses when fertilization was performed with inoculated slurry compared to inoculated manure. Finally, it could be shown that by introducing a simple washing step, the bacterial contamination was reduced in most cases or even was removed completely in some cases

  3. 9 CFR 113.36 - Detection of pathogens by the chicken inoculation test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Detection of pathogens by the chicken inoculation test. 113.36 Section 113.36 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS...

  4. Fate of pathogenic bacteria in microcosms mimicking human body sites.

    PubMed

    Castellani, Francesco; Ghidini, Valentina; Tafi, Maria Carla; Boaretti, Marzia; Lleo, Maria M

    2013-07-01

    During the infectious process, pathogens may reach anatomical sites where they are exposed to substances interfering with their growth. These substances can include molecules produced by the host, and his resident microbial population, as well as exogenous antibacterial drugs. Suboptimal concentrations of inhibitory molecules and stress conditions found in vivo (high or low temperatures, lack of oxygen, extreme pH) might induce in bacteria the activation of survival mechanisms blocking their division capability but allowing them to stay alive. These "dormant" bacteria can be reactivated in particular circumstances and would be able to express their virulence traits. In this study, it was evaluated the effect of some environmental conditions, such as optimal and suboptimal temperatures, direct light and antibiotic sub-inhibitory concentrations doses of antibiotic, on the human pathogens Escherichia coli and Enterococcus faecalis when incubated in fluids accumulated in the body of patients with different pathologies. It is shown that inoculation in a number of accumulated body fluids and the presence of gentamicin, reliable conditions encountered during pathological states, induce stress-responding strategies enabling bacteria to persist in microcosms mimicking the human body. Significant differences were detected in Gram-negative and Gram-positive species with E. faecalis surviving, as starved or viable but non-culturable forms, in any microcosm and condition tested and E. coli activating a viable but non-culturable state only in some clinical samples. The persistence of bacteria under these conditions, being non-culturable, might explain some recurrent infections without isolation of the causative agent after application of the standard microbiological methods.

  5. The dynamics of apoplast phenolics in tobacco leaves following inoculation with bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study demonstrates that the accumulation of apoplastic phenolics is stimulated in planta in response to bacterial inoculation. Past studies have shown that levels of extracellular phenolics are elicited in plant cell suspensions in response to bacteria, and that tomato plants infected with vir...

  6. When pathogenic bacteria meet the intestinal microbiota.

    PubMed

    Rolhion, Nathalie; Chassaing, Benoit

    2016-11-01

    The intestinal microbiota is a large and diverse microbial community that inhabits the intestinal tract, containing about 100 trillion bacteria from 500-1000 distinct species that, collectively, provide multiple benefits to the host. The gut microbiota contributes to nutrient absorption and maturation of the immune system, and also plays a central role in protection of the host from enteric bacterial infection. On the other hand, many enteric pathogens have developed strategies in order to be able to outcompete the intestinal community, leading to infection and/or chronic diseases. This review will summarize findings describing the complex relationship occurring between the intestinal microbiota and enteric pathogens, as well as how future therapies can ultimately benefit from such discoveries.This article is part of the themed issue 'The new bacteriology'. PMID:27672153

  7. Effect of Essential Oils on Pathogenic Bacteria

    PubMed Central

    Nazzaro, Filomena; Fratianni, Florinda; De Martino, Laura; Coppola, Raffaele; De Feo, Vincenzo

    2013-01-01

    The increasing resistance of microorganisms to conventional chemicals and drugs is a serious and evident worldwide problem that has prompted research into the identification of new biocides with broad activity. Plants and their derivatives, such as essential oils, are often used in folk medicine. In nature, essential oils play an important role in the protection of plants. Essential oils contain a wide variety of secondary metabolites that are capable of inhibiting or slowing the growth of bacteria, yeasts and moulds. Essential oils and their components have activity against a variety of targets, particularly the membrane and cytoplasm, and in some cases, they completely change the morphology of the cells. This brief review describes the activity of essential oils against pathogenic bacteria. PMID:24287491

  8. RNA-Seq for Plant Pathogenic Bacteria

    PubMed Central

    Kimbrel, Jeffrey A.; Di, Yanming; Cumbie, Jason S.; Chang, Jeff H.

    2011-01-01

    The throughput and single-base resolution of RNA-Sequencing (RNA-Seq) have contributed to a dramatic change in transcriptomic-based inquiries and resulted in many new insights into the complexities of bacterial transcriptomes. RNA-Seq could contribute to similar advances in our understanding of plant pathogenic bacteria but it is still a technology under development with limitations and unknowns that need to be considered. Here, we review some new developments for RNA-Seq and highlight recent findings for host-associated bacteria. We also discuss the technical and statistical challenges in the practical application of RNA-Seq for studying bacterial transcriptomes and describe some of the currently available solutions. PMID:24710287

  9. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Joo; Ham, Jun-Sang; Lee, Ju-Woon; Kim, Keehyuk; Ha, Sang-Do; Jo, Cheorun

    2010-06-01

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens ( Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10 2 to 10 3 Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10 1 CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D 10 values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  10. Inoculation of Lens culinaris with Pb-resistant bacteria shows potential for phytostabilization.

    PubMed

    Jebara, Salwa Harzalli; Saadani, Omar; Fatnassi, Imen Challougui; Chiboub, Manel; Abdelkrim, Souhir; Jebara, Moez

    2015-02-01

    Phytoremediation comprises a set of plant and microbe-based technologies for remediation of soil heavy metal contamination. In this work, four Pb-resistant bacteria (Agrobacterium tumefaciens, Rahnella aquatilis, and two Pseudomonas sp.) were selected among a collection of isolates from root nodule of Lens culinaris. They had a high degree of bioaccumulation ability in nutrient medium containing 2 mM Pb, and the maximum Pb accumulation of whole cell was found after 48-h incubation. These Pb-resistant bacteria synthesized plant growth promoting substances such as indole acetic acid and siderophore. The presence of the Pb resistance genes (pbrA) in these bacteria has been confirmed by PCR. L. culinaris cultivated in two experimental soils with different levels of contamination showed that Pb contamination affected plant growth; therefore, it's co-inoculation with the consortium of Pb-resistant bacteria improved plant biomass. The present study demonstrated that lentil accumulated Pb primarily in their roots and poorly in their shoots; in addition, it's co-inoculation in moderately Pb-contaminated soil induced a reduction in Pb accumulation in roots and shoots by 22 and 80 %, respectively. Whereas in highly Pb-contaminated soil, we registered a diminution in concentration of Pb in shoots (66 %) and an augmentation in roots (21 %). The contamination of soil by Pb caused an oxidative stress in lentil plant, inducing modulation in antioxidant enzymes activities, essentially in superoxide dismutase (SOD) and peroxidase (GPOX) activities which were more pronounced in lentil cultivated in highly Pb-contaminated soil, in addition, co-inoculation enhanced these activities, suggesting the protective role of enzymatic antioxidant against Pb-induced plant stress.Thus, the present study demonstrated that co-inoculation of lentil with A. tumefaciens, R. aquatilis, and Pseudomonas sp. formed a symbiotic system useful for phytostabilization of highly and moderately Pb

  11. Inoculation of Lens culinaris with Pb-resistant bacteria shows potential for phytostabilization.

    PubMed

    Jebara, Salwa Harzalli; Saadani, Omar; Fatnassi, Imen Challougui; Chiboub, Manel; Abdelkrim, Souhir; Jebara, Moez

    2015-02-01

    Phytoremediation comprises a set of plant and microbe-based technologies for remediation of soil heavy metal contamination. In this work, four Pb-resistant bacteria (Agrobacterium tumefaciens, Rahnella aquatilis, and two Pseudomonas sp.) were selected among a collection of isolates from root nodule of Lens culinaris. They had a high degree of bioaccumulation ability in nutrient medium containing 2 mM Pb, and the maximum Pb accumulation of whole cell was found after 48-h incubation. These Pb-resistant bacteria synthesized plant growth promoting substances such as indole acetic acid and siderophore. The presence of the Pb resistance genes (pbrA) in these bacteria has been confirmed by PCR. L. culinaris cultivated in two experimental soils with different levels of contamination showed that Pb contamination affected plant growth; therefore, it's co-inoculation with the consortium of Pb-resistant bacteria improved plant biomass. The present study demonstrated that lentil accumulated Pb primarily in their roots and poorly in their shoots; in addition, it's co-inoculation in moderately Pb-contaminated soil induced a reduction in Pb accumulation in roots and shoots by 22 and 80 %, respectively. Whereas in highly Pb-contaminated soil, we registered a diminution in concentration of Pb in shoots (66 %) and an augmentation in roots (21 %). The contamination of soil by Pb caused an oxidative stress in lentil plant, inducing modulation in antioxidant enzymes activities, essentially in superoxide dismutase (SOD) and peroxidase (GPOX) activities which were more pronounced in lentil cultivated in highly Pb-contaminated soil, in addition, co-inoculation enhanced these activities, suggesting the protective role of enzymatic antioxidant against Pb-induced plant stress.Thus, the present study demonstrated that co-inoculation of lentil with A. tumefaciens, R. aquatilis, and Pseudomonas sp. formed a symbiotic system useful for phytostabilization of highly and moderately Pb

  12. Potent antibacterial nanoparticles for pathogenic bacteria.

    PubMed

    Lai, Hong-Zheng; Chen, Wei-Yu; Wu, Ching-Yi; Chen, Yu-Chie

    2015-01-28

    Antibiotic-resistant bacteria have emerged because of the prevalent use of antibacterial agents. Thus, new antibacterial agents and therapeutics that can treat bacterial infections are necessary. Vancomycin is a potent antibiotic. Unfortunately, some bacterial strains have developed their resistance toward vancomycin. Nevertheless, it has been demonstrated that vancomycin-immobilized nanoparticles (NPs) are capable to be used in inhibition of the cell growth of vancomycin-resistant bacterial strains through multivalent interactions. However, multistep syntheses are usually necessary to generate vancomycin-immobilized NPs. Thus, maintaining the antibiotic activity of vancomycin when the drug is immobilized on the surface of NPs is challenging. In this study, a facile approach to generate vancomycin immobilized gold (Van-Au) NPs through one-pot stirring of vancomycin with aqueous tetrachloroauric acid at pH 12 and 25 °C for 24 h was demonstrated. Van-Au NPs (8.4 ± 1.3 nm in size) were readily generated. The generated Van-Au NPs maintained their antibiotic activities and inhibited the cell growth of pathogens, which included Gram-positive and Gram-negative bacteria as well as antibiotic-resistant bacterial strains. Furthermore, the minimum inhibitory concentration of the Van-Au NPs against bacteria was lower than that of free-form vancomycin. Staphylococcus aureus-infected macrophages were used as the model samples to examine the antibacterial activity of the Van-Au NPs. Macrophages have the tendency to engulf Van-Au NPs through endocytosis. The results showed that the cell growth of S. aureus in the macrophages was effectively inhibited, suggesting the potential of using the generated Van-Au NPs as antibacterial agents for bacterial infectious diseases.

  13. Effect of microalgae inoculation on the start-up of microalgae-bacteria systems treating municipal, piggery and digestate wastewaters.

    PubMed

    Arango, Liz; Cuervo, Flor M; González-Sánchez, Armando; Buitrón, Germán

    2016-01-01

    The effect of the inoculation of a microalgae-bacteria system on the removal of nutrients and organic matter using municipal, piggery and digestate wastewaters was evaluated. Three conditions for each substrate were evaluated: (1) inoculation with activated sludge and illumination, (2) inoculation with activated sludge without illumination, and (3) inoculation with activated sludge plus a native microalgae consortium under illumination. The illuminated reactors that were inoculated only with activated sludge developed microalgae after 12 operation days. In these reactors, the formation of flocs was observed affecting the sedimentation of the biomass positively. The removal of chemical oxygen demand, ammonium and phosphorous reached 84%, 65% and 77%, respectively.

  14. Effect of microalgae inoculation on the start-up of microalgae-bacteria systems treating municipal, piggery and digestate wastewaters.

    PubMed

    Arango, Liz; Cuervo, Flor M; González-Sánchez, Armando; Buitrón, Germán

    2016-01-01

    The effect of the inoculation of a microalgae-bacteria system on the removal of nutrients and organic matter using municipal, piggery and digestate wastewaters was evaluated. Three conditions for each substrate were evaluated: (1) inoculation with activated sludge and illumination, (2) inoculation with activated sludge without illumination, and (3) inoculation with activated sludge plus a native microalgae consortium under illumination. The illuminated reactors that were inoculated only with activated sludge developed microalgae after 12 operation days. In these reactors, the formation of flocs was observed affecting the sedimentation of the biomass positively. The removal of chemical oxygen demand, ammonium and phosphorous reached 84%, 65% and 77%, respectively. PMID:26877054

  15. Stone-isolated carbonatogenic bacteria as inoculants in bioconsolidation treatments for historical limestone.

    PubMed

    Jroundi, Fadwa; Gómez-Suaga, Patricia; Jimenez-Lopez, Concepción; González-Muñoz, Maria Teresa; Fernandez-Vivas, Maria Antonia

    2012-05-15

    Stone consolidation treatments that use bacterial biomineralization are mainly based on two strategies: (1) the inoculation of a bacterial culture with proven carbonatogenic ability and/or (2) the application of a culture medium capable of activating those bacteria able to induce the formation of calcium carbonate, from amongst the bacterial community of the stone. While the second strategy has been demonstrated to be effective and, unlike first strategy, it does not introduce any exogenous microorganism into the stone, problems may arise when the bacterial community of the stone is altered, for instance by the use of biocides in the cleaning process. In this study we isolate bacteria that belong to the natural microbial community of the stone and which have proven biomineralization capabilities, with the aim of preparing an inoculum that may be used in stone consolidation treatments wherein the natural community of those stones is altered. With this aim, outdoor experiments were undertaken to activate and isolate bacteria that display high biomineralization capacity from altered calcarenite stone. Most of the bacteria precipitated calcium carbonate in the form of calcite. The selected bacteria were phylogenetically affiliated with members of Actinobacteria, Gamma-proteobacteria and Firmicutes. Furthermore, the capability of these selected carbonatogenic bacteria to consolidate altered calcarenite stone slabs was studied in in vitro experiments, both in the presence and the absence of Myxococcus xanthus, as a potential reinforcement for the bacterial biomineralization. Herein, Acinetobacter species, belonging to the microbial community of the stone, are proposed as powerful carbonatogenic bacteria that, inoculated under appropriate conditions, may be used as inoculum for calcareous stone conservation/consolidation in restoration interventions where the microbial community of the stone is altered.

  16. Effects of nitrogen fertilization and soil inoculation of sulfur oxidizing or nitrogen fixing bacteria on onion plant growth and yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field experiment was conducted in a newly reclaimed soil at El-Saff region, El-Giza Governorate, Egypt to study the effects of different rates of nitrogen (N;62 to 248 kg ha-1) with or without soil inoculation of sulfur (S) oxidizing bacteria (SoxB), and combined inoculation of SoxB and N fixing b...

  17. Effects of gamma irradiation on the viability and phenotypic characteristics of Salmonella Enteritidis inoculated into specific-pathogen-free eggs.

    PubMed

    Rodrigues, Elizabeth C P; Souza, Mauro C L; Toledo, Sandro S; Barbosa, Celso G; Reis, Eliane M F; Rodrigues, Dalia P; Lázaro, Norma S

    2011-12-01

    The goal of this study was to determine the effects of various levels of gamma irradiation on the phenotypic characteristics of 20 strains of Salmonella Enteritidis inoculated separately into specific-pathogen-free shell eggs. Bacterial strains were inoculated into egg yolks and exposed to (60)Co radiation at doses of 0.49 to 5.0 kGy. The eggs were maintained at 25°C and analyzed for the presence of Salmonella on days 1, 2, 4, and 7, and the recovered Salmonella isolates were characterized biochemically. All strains were resistant to doses of 0.49, 0.54, 0.59, 0.8, and 1 kGy; colony counts were ≥10(5) CFU/ml of egg yolk except for one strain, which was detected at 96 h and at 7 days after irradiation at 1 kGy, with a population reduction of 2 log CFU/ml. For the other evaluated doses, 12 strains (60.0%) were resistant at 1.5 kGy and 7 strains (35.0%) were resistant at 3.0 kGy. Among all analyzed strains, 5.0 kGy was more effective for reducing and/or eliminating the inoculated bacteria; only two (10%) strains were resistant to this level of irradiation. Salmonella colony counts were significantly reduced (P < 0.01) with increasing doses from the day 1 to 7 of observation, when microbial growth peaked. Loss of mobility, lactose fermentation, citrate utilization, and hydrogen sulfide production occurred in some strains after irradiation independent of dose and postirradiation storage time. Increases in antibiotic susceptibility also occurred: seven strains became sensitive to β-lactams, two strains became sensitive to antifolates, and one strain each became sensitive to fluoroquinolone, phenicol, nitrofurans, tetracyclines, and aminoglycosides. The results indicate that up to 5.0 kGy of radiation applied to shell eggs inoculated with Salmonella Enteritidis at 4 log CFU per egg is not sufficient for complete elimination of this pathogen from this food matrix.

  18. Molecular basis of host specificity in human pathogenic bacteria

    PubMed Central

    Pan, Xiaolei; Yang, Yang; Zhang, Jing-Ren

    2014-01-01

    Pathogenic bacteria display various levels of host specificity or tropism. While many bacteria can infect a wide range of hosts, certain bacteria have strict host selectivity for humans as obligate human pathogens. Understanding the genetic and molecular basis of host specificity in pathogenic bacteria is important for understanding pathogenic mechanisms, developing better animal models and designing new strategies and therapeutics for the control of microbial diseases. The molecular mechanisms of bacterial host specificity are much less understood than those of viral pathogens, in part due to the complexity of the molecular composition and cellular structure of bacterial cells. However, important progress has been made in identifying and characterizing molecular determinants of bacterial host specificity in the last two decades. It is now clear that the host specificity of bacterial pathogens is determined by multiple molecular interactions between the pathogens and their hosts. Furthermore, certain basic principles regarding the host specificity of bacterial pathogens have emerged from the existing literature. This review focuses on selected human pathogenic bacteria and our current understanding of their host specificity. PMID:26038515

  19. Laser-Based Identification of Pathogenic Bacteria

    ERIC Educational Resources Information Center

    Rehse, Steven J.

    2009-01-01

    Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

  20. Contamination of water resources by pathogenic bacteria

    PubMed Central

    2014-01-01

    Water-borne pathogen contamination in water resources and related diseases are a major water quality concern throughout the world. Increasing interest in controlling water-borne pathogens in water resources evidenced by a large number of recent publications clearly attests to the need for studies that synthesize knowledge from multiple fields covering comparative aspects of pathogen contamination, and unify them in a single place in order to present and address the problem as a whole. Providing a broader perceptive of pathogen contamination in freshwater (rivers, lakes, reservoirs, groundwater) and saline water (estuaries and coastal waters) resources, this review paper attempts to develop the first comprehensive single source of existing information on pathogen contamination in multiple types of water resources. In addition, a comprehensive discussion describes the challenges associated with using indicator organisms. Potential impacts of water resources development on pathogen contamination as well as challenges that lie ahead for addressing pathogen contamination are also discussed. PMID:25006540

  1. Contamination of water resources by pathogenic bacteria.

    PubMed

    Pandey, Pramod K; Kass, Philip H; Soupir, Michelle L; Biswas, Sagor; Singh, Vijay P

    2014-01-01

    Water-borne pathogen contamination in water resources and related diseases are a major water quality concern throughout the world. Increasing interest in controlling water-borne pathogens in water resources evidenced by a large number of recent publications clearly attests to the need for studies that synthesize knowledge from multiple fields covering comparative aspects of pathogen contamination, and unify them in a single place in order to present and address the problem as a whole. Providing a broader perceptive of pathogen contamination in freshwater (rivers, lakes, reservoirs, groundwater) and saline water (estuaries and coastal waters) resources, this review paper attempts to develop the first comprehensive single source of existing information on pathogen contamination in multiple types of water resources. In addition, a comprehensive discussion describes the challenges associated with using indicator organisms. Potential impacts of water resources development on pathogen contamination as well as challenges that lie ahead for addressing pathogen contamination are also discussed.

  2. Interactions between the microbiota and pathogenic bacteria in the gut.

    PubMed

    Bäumler, Andreas J; Sperandio, Vanessa

    2016-07-01

    The microbiome has an important role in human health. Changes in the microbiota can confer resistance to or promote infection by pathogenic bacteria. Antibiotics have a profound impact on the microbiota that alters the nutritional landscape of the gut and can lead to the expansion of pathogenic populations. Pathogenic bacteria exploit microbiota-derived sources of carbon and nitrogen as nutrients and regulatory signals to promote their own growth and virulence. By eliciting inflammation, these bacteria alter the intestinal environment and use unique systems for respiration and metal acquisition to drive their expansion. Unravelling the interactions between the microbiota, the host and pathogenic bacteria will produce strategies for manipulating the microbiota against infectious diseases. PMID:27383983

  3. Interactions between the microbiota and pathogenic bacteria in the gut.

    PubMed

    Bäumler, Andreas J; Sperandio, Vanessa

    2016-07-06

    The microbiome has an important role in human health. Changes in the microbiota can confer resistance to or promote infection by pathogenic bacteria. Antibiotics have a profound impact on the microbiota that alters the nutritional landscape of the gut and can lead to the expansion of pathogenic populations. Pathogenic bacteria exploit microbiota-derived sources of carbon and nitrogen as nutrients and regulatory signals to promote their own growth and virulence. By eliciting inflammation, these bacteria alter the intestinal environment and use unique systems for respiration and metal acquisition to drive their expansion. Unravelling the interactions between the microbiota, the host and pathogenic bacteria will produce strategies for manipulating the microbiota against infectious diseases.

  4. Cytochemical Labeling for Fungal and Host Components in Plant Tissues Inoculated with Fungal Wilt Pathogens

    NASA Astrophysics Data System (ADS)

    Ouellette, G. B.; Baayen, R. P.; Chamberland, H.; Simard, M.; Rioux, D.; Charest, P. M.

    2004-08-01

    Antibodies to detect pectin in present investigations attached to distinct fibrils in vessel lumina. In carnation infected with an isolate of Fusarium oxysporum f.sp., labeling of pathogen cells also occurred; in a resistant cultivar (cv.), it was coincident with proximate pectin fibrils and linked to altered fungal walls, which was the opposite in the susceptible cv., indicating that hindrance of pathogen ability to degrade pectin may be related to resistance. Labeling of the fungus in culture was nil, except in media containing pectin, showing that pectin is not native to the pathogen. Labeling of fungal walls for cellulose in elm (inoculated with Ophiostoma novo-ulmi) and carnation also occurred, linked to adsorbed host wall components. The chitin probe often attached to dispersed matter, in vessel lumina, traceable to irregularly labeled fungal cells and host wall degradation products. With an anti-horseradish peroxidase probe, host and fungal walls were equally labeled, and with a glucosidase, differences of labeling between these walls were observed, depending on pH of the test solution. Fungal extracellular matter and filamentous structures, present in fungal walls, predominantly in another elm isolate (Phaeotheca dimorphospora), did not label with any of the probes used. However, in cultures of this fungus, extracellular material labeled, even at a distance from the colony margin, with an anti-fimbriae probe.

  5. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria.

    PubMed

    Denoncourt, Alix M; Paquet, Valérie E; Charette, Steve J

    2014-01-01

    Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.

  6. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria.

    PubMed

    Denoncourt, Alix M; Paquet, Valérie E; Charette, Steve J

    2014-01-01

    Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse. PMID:24904553

  7. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    PubMed Central

    Denoncourt, Alix M.; Paquet, Valérie E.; Charette, Steve J.

    2014-01-01

    Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse. PMID:24904553

  8. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria

    PubMed Central

    Cunha, Larissa D.; Zamboni, Dario S.

    2013-01-01

    Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen replication. Not surprisingly, bona fide intracellular pathogens developed strategies for manipulation of cell death to guarantee intracellular replication. In this sense, the remarkable advances in the knowledge of the inflammasome field have been accompanied by several reports characterizing the inhibition of this platform by several pathogenic bacteria. Herein, we review some processes used by pathogenic bacteria, including Yersinia spp., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Chlamydia trachomatis, Francisella tularensis, Shigella flexneri, Legionella pneumophila, and Coxiella burnetii to evade the activation of the inflammasome and the induction of pyroptosis. PMID:24324933

  9. LOW PATHOGENIC POTENTIAL IN HETEROTROPHIC BACTERIA FROM POTABLE WATER

    EPA Science Inventory

    Forty-five isolates of HPC bacteria, most of which express virulence-related characteristics are being tested for pathogenicity in immunocompromised mice. All forty-five were negative for facultative intracellular pathogenicity. All twenty-three isolates tested thus far were a...

  10. Hrp mutant bacteria as biocontrol agents: toward a sustainable approach in the fight against plant pathogenic bacteria.

    PubMed

    Hanemian, Mathieu; Zhou, Binbin; Deslandes, Laurent; Marco, Yves; Trémousaygue, Dominique

    2013-10-01

    Sustainable agriculture necessitates development of environmentally safe methods to protect plants against pathogens. Among these methods, application of biocontrol agents has been efficiently used to minimize disease development. Here we review current understanding of mechanisms involved in biocontrol of the main Gram-phytopathogenic bacteria-induced diseases by plant inoculation with strains mutated in hrp (hypersensitive response and pathogenicity) genes. These mutants are able to penetrate plant tissues and to stimulate basal resistance of plants. Novel protection mechanisms involving the phytohormone abscisic acid appear to play key roles in the biocontrol of wilt disease induced by Ralstonia solanacearum in Arabidopsis thaliana. Fully understanding these mechanisms and extending the studies to other pathosystems are still required to evaluate their importance in disease protection.

  11. Plant-pathogenic bacteria as biological weapons - real threats?

    PubMed

    Young, J M; Allen, C; Coutinho, T; Denny, T; Elphinstone, J; Fegan, M; Gillings, M; Gottwald, T R; Graham, J H; Iacobellis, N S; Janse, J D; Jacques, M-A; Lopez, M M; Morris, C E; Parkinson, N; Prior, P; Pruvost, O; Neto, J Rodrigues; Scortichini, M; Takikawa, Y; Upper, C D

    2008-10-01

    At present, much attention is being given to the potential of plant pathogens, including plant-pathogenic bacteria, as biological weapons/bioterror weapons. These two terms are sometimes used interchangeably and there is need for care in their application. It has been claimed that clandestine introduction of certain plant-pathogenic bacteria could cause such crop losses as to impact so significantly on a national economy and thus constitute a threat to national security. As a separate outcome, it is suggested that they could cause serious public alarm, perhaps constituting a source of terror. Legislation is now in place to regulate selected plant-pathogenic bacteria as potential weapons. However, we consider it highly doubtful that any plant-pathogenic bacterium has the requisite capabilities to justify such a classification. Even if they were so capable, the differentiation of pathogens into a special category with regulations that are even more restrictive than those currently applied in quarantine legislation of most jurisdictions offers no obvious benefit. Moreover, we believe that such regulations are disadvantageous insofar as they limit research on precisely those pathogens most in need of study. Whereas some human and animal pathogens may have potential as biological or bioterror weapons, we conclude that it is unlikely that any plant-pathogenic bacterium realistically falls into this category.

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

    NASA Astrophysics Data System (ADS)

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

    2005-06-01

    The standard method of immunomagnetic separation for isolating pathogenic bacteria from food and environmental matrices processes 1 ml volumes. Pathogens present at low levels (<0.5 pathogenic bacteria/g) will not be consistently detected by this method. Here a multiple sample flow through immunomagnetic separator has been designed and tested to process large volume samples (50 to 250 ml). Preliminary results show >97% recovery of polydisperse magnetic particles (diameter range 1 to 8 µm) containing 29-33% w/w Fe3O4 content. Between 70 and 130 times more of the pathogenic bacteria Escherichia coli O157 is recovered from PBS compared with the standard 1 ml method. Also, the recovery of E. coli O157 from beef mince homogenates, after a 4 h incubation at 42 °C, is between 80 and 180 times higher than the standard 1 ml method.

  13. Inoculation of tannin-degrading bacteria into novel hosts increases performance on tannin-rich diets.

    PubMed

    Kohl, Kevin D; Stengel, Ashley; Dearing, M Denise

    2016-06-01

    It has been hypothesized that herbivores host tannin-degrading bacteria (TDB) to overcome the toxic challenges posed by plant tannins. While TDB have been isolated from the guts of numerous mammals, their functional significance to their hosts has never been explicitly tested. We introduced TDB into lab rats, which do not host TDB, and measured host performance on tannin-rich diets. We first isolated three species of TDB, Escherichia coli, Bacillus subtilis and Enterococcus faecalis, from the guts of the desert woodrat (Neotoma lepida), which regularly feeds on tannin-rich plants. Then, we inoculated isolated TDB, as well as full woodrat microbial communities into laboratory rats. A control group was inoculated with sterilized woodrat faeces. Recipient lab rats were fed increasing concentrations of tannic acid, and we monitored tannic acid intake, body mass and liver damage as measured by serum alanine aminotransferase activity. Lab rats given TDB as isolates or full communities exhibited increased tannic acid intake, higher maintenance of body mass and lower indicators of liver damage compared with control animals. These differences were maintained when the trial was repeated after 6 weeks of feeding on tannin-free diets. Our results are the first to demonstrate that TDB significantly increase host performance on tannin-rich diets.

  14. Natural soil reservoirs for human pathogenic and fecal indicator bacteria

    USGS Publications Warehouse

    Boschiroli, Maria L; Falkinham, Joseph; Favre-Bonte, Sabine; Nazaret, Sylvie; Piveteau, Pascal; Sadowsky, Michael J.; Byappanahalli, Muruleedhara; Delaquis, Pascal; Hartmann, Alain

    2016-01-01

    Soils receive inputs of human pathogenic and indicator bacteria through land application of animal manures or sewage sludge, and inputs by wildlife. Soil is an extremely heterogeneous substrate and contains meso- and macrofauna that may be reservoirs for bacteria of human health concern. The ability to detect and quantify bacteria of human health concern is important in risk assessments and in evaluating the efficacy of agricultural soil management practices that are protective of crop quality and protective of adjacent water resources. The present chapter describes the distribution of selected Gram-positive and Gram-negative bacteria in soils. Methods for detecting and quantifying soilborne bacteria including extraction, enrichment using immunomagnetic capture, culturing, molecular detection and deep sequencing of metagenomic DNA to detect pathogens are overviewed. Methods for strain phenotypic and genotypic characterization are presented, as well as how comparison with clinical isolates can inform the potential for human health risk.

  15. Detection of pathogenic gram negative bacteria using infrared thermography

    NASA Astrophysics Data System (ADS)

    Lahiri, B. B.; Divya, M. P.; Bagavathiappan, S.; Thomas, Sabu; Philip, John

    2012-11-01

    Detection of viable bacteria is of prime importance in all fields of microbiology and biotechnology. Conventional methods of enumerating bacteria are often time consuming and labor-intensive. All living organisms generate heat due to metabolic activities and hence, measurement of heat energy is a viable tool for detection and quantification of bacteria. In this article, we employ a non-contact and real time method - infrared thermography (IRT) for measurement of temperature variations in four clinically significant gram negative pathogenic bacteria, viz. Vibrio cholerae, Vibrio mimicus, Proteus mirabilis and Pseudomonas aeruginosa. We observe that, the energy content, defined as the ratio of heat generated by bacterial metabolic activities to the heat lost from the liquid medium to the surrounding, vary linearly with the bacterial concentration in all the four pathogenic bacteria. The amount of energy content observed in different species is attributed to their metabolisms and morphologies that affect the convection velocity and hence heat transport in the medium.

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

    PubMed

    Bator, Tomasz

    2010-01-01

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

  17. [Free-living amoebae as vehicles of pathogenic bacteria].

    PubMed

    Derda, Monika; Sułek-Stankiewicz, Anna; Hadaś, Edward

    2006-01-01

    The free-living amoebae are ubiquitous organisms. They are found in humid soil and all water reservoirs, i.e. fresh, sea, freezing and hot water. They mainly feed on bacteria. Pathogenic properties of amoebae and the mechanisms underlying pathological changes induced during human infection have not yet been fully elucidated. They are the causative agents of primary amoebic meningo-encephalitis (PAM), granulomatous amebic encephalitis (GAE), a chronic progressive disease of the central nervous system, amebic keratitis (AK), a chronic eye infection; amebic pneumitis (AP), a chronic lung infection, and skin infection. Only a few isolates are strongly and permanently pathogenic to humans. Some isolates lose their pathogenic properties after one passage. It has been assumed that such "temporary", unstable pathogenic properties of the amoebae may be caused by internal factors carried by them. It is generally known that the free-living amoebae may be naturally infected with pathogenic bacteria, which have the ability to survive for a long time and to proliferate in the amoebae cells. The role of the amoeba in the process of maintaining, propagating and transmitting human pathogens has not been well recognized. It has been suggested that some infections can be acquired by inhaling aerosols containing amoebae cells filled with bacteria. The presence of bacteria inside the free-living amoebae possess a great challenge to organisations responsible for testing and inspecting the quality and cleanliness of surface waters, swimming pools and drinking water intakes.

  18. Effects of lactic acid bacteria silage inoculation on methane emission and productivity of Holstein Friesian dairy cattle.

    PubMed

    Ellis, J L; Hindrichsen, I K; Klop, G; Kinley, R D; Milora, N; Bannink, A; Dijkstra, J

    2016-09-01

    Inoculants of lactic acid bacteria (LAB) are used to improve silage quality and prevent spoilage via increased production of lactic acid and other organic acids and a rapid decline in silage pH. The addition of LAB inoculants to silage has been associated with increases in silage digestibility, dry matter intake (DMI), and milk yield. Given the potential change in silage and rumen fermentation conditions accompanying these silage additives, the aim of this study was to investigate the effect of LAB silage inoculants on DMI, digestibility, milk yield, milk composition, and methane (CH4) production from dairy cows in vivo. Eight mid-lactation Holstein-Friesian dairy cows were grouped into 2 blocks of 4 cows (multiparous and primiparous) and used in a 4×4 double Latin square design with 21-d periods. Methane emissions were measured by indirect calorimetry. Treatments were grass silage (mainly ryegrass) with no inoculant (GS), with a long-term inoculant (applied at harvest; GS+L), with a short-term inoculant (applied 16h before feeding; GS+S), or with both long and short-term inoculants (GS+L+S). All diets consisted of grass silage and concentrate (75:25 on a dry matter basis). The long-term inoculant consisted of a 10:20:70 mixture of Lactobacillus plantarum, Lactococcus lactis, and Lactobacillus buchneri, and the short-term inoculant was a preparation of Lc. lactis. Dry matter intake was not affected by long-term or short-term silage inoculation, nor was dietary neutral detergent fiber or fat digestibility, or N or energy balance. Milk composition (except milk urea) and fat and protein-corrected milk yield were not affected by long- or short-term silage inoculation, nor was milk microbial count. However, milk yield tended to be greater with long-term silage inoculation. Methane expressed in units of grams per day, grams per kilogram of DMI, grams per kilogram of milk, or grams per kilogram of fat and protein-corrected milk yield was not affected by long- or short

  19. Effects of lactic acid bacteria silage inoculation on methane emission and productivity of Holstein Friesian dairy cattle.

    PubMed

    Ellis, J L; Hindrichsen, I K; Klop, G; Kinley, R D; Milora, N; Bannink, A; Dijkstra, J

    2016-09-01

    Inoculants of lactic acid bacteria (LAB) are used to improve silage quality and prevent spoilage via increased production of lactic acid and other organic acids and a rapid decline in silage pH. The addition of LAB inoculants to silage has been associated with increases in silage digestibility, dry matter intake (DMI), and milk yield. Given the potential change in silage and rumen fermentation conditions accompanying these silage additives, the aim of this study was to investigate the effect of LAB silage inoculants on DMI, digestibility, milk yield, milk composition, and methane (CH4) production from dairy cows in vivo. Eight mid-lactation Holstein-Friesian dairy cows were grouped into 2 blocks of 4 cows (multiparous and primiparous) and used in a 4×4 double Latin square design with 21-d periods. Methane emissions were measured by indirect calorimetry. Treatments were grass silage (mainly ryegrass) with no inoculant (GS), with a long-term inoculant (applied at harvest; GS+L), with a short-term inoculant (applied 16h before feeding; GS+S), or with both long and short-term inoculants (GS+L+S). All diets consisted of grass silage and concentrate (75:25 on a dry matter basis). The long-term inoculant consisted of a 10:20:70 mixture of Lactobacillus plantarum, Lactococcus lactis, and Lactobacillus buchneri, and the short-term inoculant was a preparation of Lc. lactis. Dry matter intake was not affected by long-term or short-term silage inoculation, nor was dietary neutral detergent fiber or fat digestibility, or N or energy balance. Milk composition (except milk urea) and fat and protein-corrected milk yield were not affected by long- or short-term silage inoculation, nor was milk microbial count. However, milk yield tended to be greater with long-term silage inoculation. Methane expressed in units of grams per day, grams per kilogram of DMI, grams per kilogram of milk, or grams per kilogram of fat and protein-corrected milk yield was not affected by long- or short

  20. [Current concepts on the pathogenicity of phytopathogenic bacteria].

    PubMed

    Boucher, C; Genin, S; Arlat, M

    2001-10-01

    What are the molecular determinants that make a bacterium a plant pathogen? In the last 10-20 years, important progress has been made in answering this question. In the early 20th century soon after the discovery of infectious diseases, the first studies of pathogenicity were undertaken. These early studies relied mostly on biochemistry and led to the discovery of several major pathogenicity determinants, such as toxins and hydrolytic enzymes which govern the production of major disease symptoms. From these pioneering studies, a simplistic view of pathogenicity arose. It was thought that only a few functions were sufficient to transform a bacterium into a pathogen. This view rapidly changed when modern techniques of molecular genetics were applied to analyse pathogenicity. Modern analyses of pathogenicity determinants took advantage of the relatively simple organization of the haploid genome of pathogenic bacteria. By creating non-pathogenic mutants, a large number of genes governing bacterium-host interactions were identified. These genes are required either for host colonization or for the production of symptoms. Even though the role of motility and chemotaxis in these processes is still unclear, it is clear that a strong attachment of Agrobacterium to plant cells is a prerequisite for efficient plant transformation and disease. Other important pathogenicity factors identified with a molecular genetic approach include hydrolytic enzymes such as pectinases and cellulases which not only provide nutrients to the bacteria but also facilitate pathogen invasion into host tissues. The precise role of exopolysaccharide in pathogenicity is still under discussion, however it is has been established that it is crucial for the induction of wilt symptoms caused by Ralstonia solanacearum. Trafficking of effector proteins from the invading bacterium into the host cell emerged recently as a new central concept. In plant pathogenic bacteria, protein translocation takes place

  1. Pathogen bacteria adhesion to skin mucus of fishes.

    PubMed

    Benhamed, Said; Guardiola, Francisco A; Mars, Mohammed; Esteban, María Ángeles

    2014-06-25

    Fish are always in intimate contact with their environment; therefore they are permanently exposed to very vary external hazards (e.g. aerobic and anaerobic bacteria, viruses, parasites, pollutants). To fight off pathogenic microorganisms, the epidermis and its secretion, the mucus acts as a barrier between the fish and the environment. Fish are surrounded by a continuous layer of mucus which is the first physical, chemical and biological barrier from infection and the first site of interaction between fish's skin cells and pathogens. The mucus composition is very complex and includes numerous antibacterial factors secreted by fish's skin cells, such as immunoglobulins, agglutinins, lectins, lysins and lysozymes. These factors have a very important role to discriminate between pathogenic and commensal microorganisms and to protect fish from invading pathogens. Furthermore, the skin mucus represents an important portal of entry of pathogens since it induces the development of biofilms, and represents a favorable microenvironment for bacteria, the main disease agents for fish. The purpose of this review is to summarize the current knowledge of the interaction between bacteria and fish skin mucus, the adhesion mechanisms of pathogens and the major factors influencing pathogen adhesion to mucus. The better knowledge of the interaction between fish and their environment could inspire other new perspectives to study as well as to exploit the mucus properties for different purposes.

  2. Interaction of a free-living soil nematode, Caenorhabditis elegans, with surrogates of foodborne pathogenic bacteria.

    PubMed

    Anderson, Gary L; Caldwell, Krishaun N; Beuchat, Larry R; Williams, Phillip L

    2003-09-01

    Free-living nematodes may harbor, protect, and disperse bacteria, including those ingested and passed in viable form in feces. These nematodes are potential vectors for human pathogens and may play a role in foodborne diseases associated with fruits and vegetables eaten raw. In this study, we evaluated the associations between a free-living soil nematode, Caenorhabditis elegans, and Escherichia coli, an avirulent strain of Salmonella Typhimurium, Listeria welshimeri, and Bacillus cereus. On an agar medium, young adult worms quickly moved toward colonies of all four bacteria; over 90% of 3-day-old adult worms entered colonies within 16 min after inoculation. After 48 h, worms moved in and out of colonies of L. welshimeri and B. cereus but remained associated with E. coli and Salmonella Typhimurium colonies for at least 96 h. Young adult worms fed on cells of the four bacteria suspended in K medium. Worms survived and reproduced with the use of nutrients derived from all test bacteria, as determined for eggs laid by second-generation worms after culturing for 96 h. Development was slightly slower for worms fed gram-positive bacteria than for worms fed gram-negative bacteria. Worms that fed for 24 h on bacterial lawns formed on tryptic soy agar dispersed bacteria over a 3-h period when they were transferred to a bacteria-free agar surface. The results of this study suggest that C. elegans and perhaps other free-living nematodes are potential vectors for both gram-positive and gram-negative bacteria, including foodborne pathogens in soil.

  3. Development of a greenhouse-based inoculation protocol for the fungus Colletotrichum cereale pathogenic to annual bluegrass (Poa annua)

    PubMed Central

    Beirn, Lisa A.; Wang, Ruying; Clarke, Bruce B.

    2015-01-01

    The fungus Colletotrichum cereale incites anthracnose disease on Poa annua (annual bluegrass) turfgrass. Anthracnose disease is geographically widespread throughout the world and highly destructive to cool-season turfgrasses, with infections by C. cereale resulting in extensive turf loss. Comprehensive research aimed at controlling turfgrass anthracnose has been performed in the field, but knowledge of the causal organism and its basic biology is still needed. In particular, the lack of a reliable greenhouse-based inoculation protocol performed under controlled environmental conditions is an obstacle to the study of C. cereale and anthracnose disease. Our objective was to develop a consistent and reproducible inoculation protocol for the two major genetic lineages of C. cereale. By adapting previously successful field-based protocols and combining with components of existing inoculation procedures, the method we developed consistently produced C. cereale infection on two susceptible P. annua biotypes. Approximately 7 to 10 days post-inoculation, plants exhibited chlorosis and thinning consistent with anthracnose disease symptomology. Morphological inspection of inoculated plants revealed visual signs of the fungus (appressoria and acervuli), although acervuli were not always present. After stringent surface sterilization of inoculated host tissue, C. cereale was consistently re-isolated from symptomatic tissue. Real-time PCR detection analysis based on the Apn2 marker confirmed the presence of the pathogen in host tissue, with both lineages of C. cereale detected from all inoculated plants. When a humidifier was not used, no infection developed for any biotypes or fungal isolates tested. The inoculation protocol described here marks significant progress for in planta studies of C. cereale, and will enable scientifically reproducible investigations of the biology, infectivity and lifestyle of this important grass pathogen. PMID:26339538

  4. [Analysis of Pathogenic Bacteria in Reclaimed Water and Impact of UV Disinfection on the Removal of Pathogenic Bacteria].

    PubMed

    Jing, Ming; Wang, Lei

    2016-02-15

    In the study, 454-pyrosequencing technology was employed to investigate the species of pathogenic bacteria and the proportion of each pathogen in secondary effluent. Culture-based, qPCR and Q-RT-PCR methods were employed to analyze the removal of indicator (E. coli) and pathogen (Salmonella and Mycobacterium) by ultraviolet (UV) disinfection at a dose of 60 mJ x Cm(-2). The results showed that 11 kinds of pathogenic bacteria were found and the most abundant potentially pathogenic bacteria in the secondary effluent were affiliated with the genera of Clostridium (2.96%), Arcobacter (0.82%) and Mycobacterium (0.36%). 99.9% of culturable E. coli and Salmonella were removed by UV disinfection (60 mJ x cm(-2), however, less than 90% of culturable Mycobacterium were removed. The removal efficiencies of viable E. coli, Salmonella and Mycobacterium were low. Q-RT-PCR seemed to be a promising method for evaluating viable microorganisms in samples. Besides, pathogenic bacteria entered into VBNC state at a UV dose of 60 mJ x cm(-2). Other advanced treatment processes were needed to ensure safe utilization of reclaimed water. PMID:27363153

  5. [Analysis of Pathogenic Bacteria in Reclaimed Water and Impact of UV Disinfection on the Removal of Pathogenic Bacteria].

    PubMed

    Jing, Ming; Wang, Lei

    2016-02-15

    In the study, 454-pyrosequencing technology was employed to investigate the species of pathogenic bacteria and the proportion of each pathogen in secondary effluent. Culture-based, qPCR and Q-RT-PCR methods were employed to analyze the removal of indicator (E. coli) and pathogen (Salmonella and Mycobacterium) by ultraviolet (UV) disinfection at a dose of 60 mJ x Cm(-2). The results showed that 11 kinds of pathogenic bacteria were found and the most abundant potentially pathogenic bacteria in the secondary effluent were affiliated with the genera of Clostridium (2.96%), Arcobacter (0.82%) and Mycobacterium (0.36%). 99.9% of culturable E. coli and Salmonella were removed by UV disinfection (60 mJ x cm(-2), however, less than 90% of culturable Mycobacterium were removed. The removal efficiencies of viable E. coli, Salmonella and Mycobacterium were low. Q-RT-PCR seemed to be a promising method for evaluating viable microorganisms in samples. Besides, pathogenic bacteria entered into VBNC state at a UV dose of 60 mJ x cm(-2). Other advanced treatment processes were needed to ensure safe utilization of reclaimed water.

  6. Chemical signaling between plants and plant-pathogenic bacteria.

    PubMed

    Venturi, Vittorio; Fuqua, Clay

    2013-01-01

    Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.

  7. Induction of Defense-Related Ultrastructural Modifications in Pea Root Tissues Inoculated with Endophytic Bacteria.

    PubMed Central

    Benhamou, N.; Kloepper, J. W.; Quadt-Hallman, A.; Tuzun, S.

    1996-01-01

    The stimulation exerted by the endophytic bacterium Bacillus pumilus strain SE34 in plant defense reactions was investigated at the ultrastructural level using an in vitro system in which root-inducing T-DNA pea (Pisum sativum L.) roots were infected with the pea root-rotting fungus Fusarium oxysporum f. sp. pisi. In nonbacterized roots, the pathogen multiplied abundantly through much of the tissue including the vascular stele, whereas in prebacterized roots, pathogen growth was restricted to the epidermis and the outer cortex In these prebacterized roots, typical host reactions included strengthening the epidermal and cortical cell walls and deposition of newly formed barriers beyond the infection sites. Wall appositions were found to contain large amounts of callose in addition to being infiltrated with phenolic compounds. The labeling pattern obtained with the gold-complexed laccase showed that phenolics were widely distributed in Fusarium-challenged, bacterized roots. Such compounds accumulated in the host cell walls and the intercellular spaces as well as at the surface or even inside of the invading hyphae of the pathogen. The wall-bound chitin component in Fusarium hyphae colonizing bacterized roots was preserved even when hyphae had undergone substantial degradation. These observations confirm that endophytic bacteria may function as potential inducers of plant disease resistance. PMID:12226427

  8. Presence of Pathogenic Bacteria and Viruses in the Daycare Environment.

    PubMed

    Ibfelt, Tobias; Engelund, Eva Hoy; Permin, Anders; Madsen, Jonas Stenløkke; Schultz, Anna Charlotte; Andersen, Leif Percival

    2015-10-01

    The number of children in daycare centers (DCCs) is rising. This increases exposure to microorganisms and infectious diseases. Little is known about which bacteria and viruses are present in the DCC environment and where they are located. In the study described in this article, the authors set out to determine the prevalence of pathogenic bacteria and viruses and to find the most contaminated fomites in DCCs. Fifteen locations in each DCC were sampled for bacteria, respiratory viruses, and gastrointestinal viruses. The locations were in the toilet, kitchen, and playroom areas and included nursery pillows, toys, and tables, among other things. Coliform bacteria were primarily found in the toilet and kitchen areas whereas nasopharyngeal bacteria were found mostly on toys and fabric surfaces in the playroom. Respiratory viruses were omnipresent in the DCC environment, especially on the toys.

  9. Presence of Pathogenic Bacteria and Viruses in the Daycare Environment.

    PubMed

    Ibfelt, Tobias; Engelund, Eva Hoy; Permin, Anders; Madsen, Jonas Stenløkke; Schultz, Anna Charlotte; Andersen, Leif Percival

    2015-10-01

    The number of children in daycare centers (DCCs) is rising. This increases exposure to microorganisms and infectious diseases. Little is known about which bacteria and viruses are present in the DCC environment and where they are located. In the study described in this article, the authors set out to determine the prevalence of pathogenic bacteria and viruses and to find the most contaminated fomites in DCCs. Fifteen locations in each DCC were sampled for bacteria, respiratory viruses, and gastrointestinal viruses. The locations were in the toilet, kitchen, and playroom areas and included nursery pillows, toys, and tables, among other things. Coliform bacteria were primarily found in the toilet and kitchen areas whereas nasopharyngeal bacteria were found mostly on toys and fabric surfaces in the playroom. Respiratory viruses were omnipresent in the DCC environment, especially on the toys. PMID:26591334

  10. Prediction of molecular mimicry candidates in human pathogenic bacteria.

    PubMed

    Doxey, Andrew C; McConkey, Brendan J

    2013-08-15

    Molecular mimicry of host proteins is a common strategy adopted by bacterial pathogens to interfere with and exploit host processes. Despite the availability of pathogen genomes, few studies have attempted to predict virulence-associated mimicry relationships directly from genomic sequences. Here, we analyzed the proteomes of 62 pathogenic and 66 non-pathogenic bacterial species, and screened for the top pathogen-specific or pathogen-enriched sequence similarities to human proteins. The screen identified approximately 100 potential mimicry relationships including well-characterized examples among the top-scoring hits (e.g., RalF, internalin, yopH, and others), with about 1/3 of predicted relationships supported by existing literature. Examination of homology to virulence factors, statistically enriched functions, and comparison with literature indicated that the detected mimics target key host structures (e.g., extracellular matrix, ECM) and pathways (e.g., cell adhesion, lipid metabolism, and immune signaling). The top-scoring and most widespread mimicry pattern detected among pathogens consisted of elevated sequence similarities to ECM proteins including collagens and leucine-rich repeat proteins. Unexpectedly, analysis of the pathogen counterparts of these proteins revealed that they have evolved independently in different species of bacterial pathogens from separate repeat amplifications. Thus, our analysis provides evidence for two classes of mimics: complex proteins such as enzymes that have been acquired by eukaryote-to-pathogen horizontal transfer, and simpler repeat proteins that have independently evolved to mimic the host ECM. Ultimately, computational detection of pathogen-specific and pathogen-enriched similarities to host proteins provides insights into potentially novel mimicry-mediated virulence mechanisms of pathogenic bacteria.

  11. Radiation resistances and decontamination of common pathogenic bacteria contaminated in white scar oyster ( Crassostrea belcheri) in Thailand

    NASA Astrophysics Data System (ADS)

    Thupila, Nunticha; Ratana-arporn, Pattama; Wilaipun, Pongtep

    2011-07-01

    In Thailand, white scar oyster ( Crassostrea belcheri) was ranked for premium quality, being most expensive and of high demand. This oyster is often eaten raw, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. As limited alternative methods are available to sterilize the oyster while preserving the raw characteristic, irradiation may be considered as an effective method for decontamination. In this study, the radiation resistance of pathogenic bacteria commonly contaminating the oyster and the optimum irradiation doses for sterilization of the most radiation resistant bacteria were investigated. The radiation decimal reduction doses ( D10) of Salmonella Weltevreden DMST 33380, Vibrio parahaemolyticus ATCC 17802 and Vibrio vulnificus DMST 5852 were determined in broth culture and inoculated oyster homogenate. The D10 values of S. Weltevreden, V. parahaemolyticus and V. vulnificus in broth culture were 0.154, 0.132 and 0.059 kGy, while those of inoculated oyster homogenate were 0.330, 0.159 and 0.140 kGy, respectively. It was found that among the pathogens tested, S. Weltevreden was proved to be the most resistant species. An irradiation dose of 1.5 kGy reduced the counts of 10 5 CFU/g S. Weltevreden inoculated in oyster meat to an undetectable level. The present study indicated that a low-dose irradiation can improve the microbial quality of oyster and further reduce the risks from the food-borne pathogens without adversely affecting the sensory attributes.

  12. V-antigen homologs in pathogenic gram-negative bacteria.

    PubMed

    Sawa, Teiji; Katoh, Hideya; Yasumoto, Hiroaki

    2014-05-01

    Gram-negative bacteria cause many types of infections in animals from fish and shrimps to humans. Bacteria use Type III secretion systems (TTSSs) to translocate their toxins directly into eukaryotic cells. The V-antigen is a multifunctional protein required for the TTSS in Yersinia and Pseudomonas aeruginosa. V-antigen vaccines and anti-V-antigen antisera confer protection against Yersinia or P. aeruginosa infections in animal models. The V-antigen forms a pentameric cap structure at the tip of the Type III secretory needle; this structure, which has evolved from the bacterial flagellar cap structure, is indispensable for toxin translocation. Various pathogenic gram-negative bacteria such as Photorhabdus luminescens, Vibrio spp., and Aeromonas spp. encode homologs of the V-antigen. Because the V-antigens of pathogenic gram-negative bacteria play a key role in toxin translocation, they are potential therapeutic targets for combatting bacterial virulence. In the USA and Europe, these vaccines and specific antibodies against V-antigens are in clinical trials investigating the treatment of Yersinia or P. aeruginosa infections. Pathogenic gram-negative bacteria are of great interest because of their ability to infect fish and shrimp farms, their potential for exploitation in biological terrorism attacks, and their ability to cause opportunistic infections in humans. Thus, elucidation of the roles of the V-antigen in the TTSS and mechanisms by which these functions can be blocked is critical to facilitating the development of improved anti-V-antigen strategies. PMID:24641673

  13. Inoculation of paperboard mill sludge versus mixed culture bacteria for hydrogen production from paperboard mill wastewater.

    PubMed

    Farghaly, Ahmed; Tawfik, Ahmed; Danial, Amal

    2016-02-01

    A comparative evaluation of paperboard mill sludge (PMS) versus mixed culture bacteria (MCB) as inoculum for hydrogen production from paperboard mill wastewater (PMW) was investigated. The experiments were conducted at different initial cultivation pHs, inoculums to substrate ratios (ISRs gVS/gCOD), and hydraulic retention times (HRTs). The peak hydrogen yield (HY) of 5.29 ± 0.16 and 1.22 ± 0.11 mmol/gCODinitial was occurred at pH = 5 for MCB and PMS, respectively. At pH of 5, the HY and COD removal achieved the highest values of 2.26 ± 0.14 mmol/gCODinitial and 86 ± 1.6% at ISR = 6 for MCB, and 2.38 ± 0.25 mmol/gCODinitial and 60.4 ± 2.5% at ISRs = 3 for PMS. The maximum hydrogen production rate was 93.75 ± 8.9 mmol/day at HRT = 9.6 h from continuous upflow anaerobic reactor inoculated with MCB. Meanwhile, the 16S ribosomal RNA (rRNA) gene fragments indicated a dominance of a novel hydrogen-producing bacterium of Stenotrophomonas maltophilia for PMS microbial community. On the other hand, Escherichia fergusonii and Enterobacter hormaechei were the predominant species for MCB.

  14. Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria.

    PubMed

    Troxell, Bryan; Hassan, Hosni M

    2013-01-01

    In the ancient anaerobic environment, ferrous iron (Fe(2+)) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe(3+)) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe(3+), bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe(3+). However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe(2+) as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria.

  15. Pathogenicity in six Australian reptile species following experimental inoculation with Bohle iridovirus.

    PubMed

    Ariel, E; Wirth, W; Burgess, G; Scott, J; Owens, L

    2015-08-20

    Ranaviruses are able to infect multiple species of fish, amphibian and reptile, and some strains are capable of interclass transmission. These numerous potential carriers and reservoir species compound efforts to control and contain infections in cultured and wild populations, and a comprehensive knowledge of susceptible species and life stage is necessary to inform such processes. Here we report on the challenge of 6 water-associated reptiles with Bohle iridovirus (BIV) to investigate its potential pathogenicity in common native reptiles of the aquatic and riparian fauna of northern Queensland, Australia. Adult tortoises Elseya latisternum and Emydura krefftii, snakes Boiga irregularis, Dendrelaphis punctulatus and Amphiesma mairii, and yearling crocodiles Crocodylus johnstoni were exposed via intracoelomic inoculation or co-habitation with infected con-specifics, but none were adversely affected by the challenge conditions applied here. Bohle iridovirus was found to be extremely virulent in hatchling tortoises E. latisternum and E. krefftii via intracoelomic challenge, as demonstrated by distinct lesions in multiple organs associated with specific immunohistochemistry staining and a lethal outcome (10/17) of the challenge. Virus was re-isolated from 2/5 E. latisternum, 4/12 E. krefftii and 1/3 brown tree snakes B. irregularis. Focal necrosis, haemorrhage and infiltration of granulocytes were frequently observed histologically in the pancreas, liver and sub-mucosa of the intestine of challenged tortoise hatchlings. Immunohistochemistry demonstrated the presence of ranavirus antigens in the necrotic lesions and in individual cells of the vascular endothelium, the connective tissue and in granulocytes associated with necrosis or present along serosal surfaces. The outcome of this study confirms hatchling tortoises are susceptible to BIV, thereby adding Australian reptiles to the host range of ranaviruses. Additionally, given that BIV was originally isolated from an

  16. Penetration of surface-inoculated bacteria as a result of electrically generated hydrodynamic shock wave treatment of boneless skinless chicken breasts.

    PubMed

    Lorca, T A; Claus, J R; Eifert, J D; Marcy, J E; Sumner, S S

    2003-07-01

    The top surface of boneless skinless chicken breasts was inoculated with either green fluorescent protein (GFP)-labeled Escherichia coli (E. coli-GFP) or rifampicin-resistant E. coli (E. coli-Rif) and subjected to electrically generated hydrodynamic shock wave treatment (HVADH). Cryostat sampling in concert with laser scanning confocal microscopy or plating onto antibiotic selective agar was used to determine if HVADH treatment resulted in the movement of the inoculated bacteria from the outer inoculated surface to the interior of intact boneless skinless chicken breasts. In HVADH-treated boneless skinless chicken breasts, marker bacteria were detected within the first 200 microm below the inoculated surface, 50 to 100 microm beyond the depth of untreated surface inoculated boneless skinless chicken breasts. The exact depth at which the marker bacteria were found was dependent on the cryostat sampling distance used. These results suggest that HVADH treatments affect the movement of surface bacteria. PMID:12872981

  17. Persistence and Potential Viable but Non-culturable State of Pathogenic Bacteria during Storage of Digestates from Agricultural Biogas Plants

    PubMed Central

    Maynaud, Geraldine; Pourcher, Anne-Marie; Ziebal, Christine; Cuny, Anais; Druilhe, Céline; Steyer, Jean-Philippe; Wéry, Nathalie

    2016-01-01

    Despite the development of on-farm anaerobic digestion as a process for making profitable use of animal by-products, factors leading to the inactivation of pathogenic bacteria during storage of digestates remain poorly described. Here, a microcosm approach was used to evaluate the persistence of three pathogenic bacteria (Salmonella enterica Derby, Campylobacter coli and Listeria monocytogenes) in digestates from farms, stored for later land spreading. Nine samples, including raw digestates, liquid fractions of digestate and composted digestates, were inoculated with each pathogen and maintained for 40 days at 24°C. Concentrations of pathogens were monitored using culture and qPCR methods. The persistence of L. monocytogenes, detected up to 20 days after inoculation, was higher than that of Salmonella Derby, detected for 7–20 days, and of C. coli (not detected after 7 days). In some digestates, the concentration of the pathogens by qPCR assay was several orders of magnitude higher than the concentration of culturable cells, suggesting a potential loss of culturability and induction of Viable but Non-Culturable (VBNC) state. The potential VBNC state which was generally not observed in the same digestate for the three pathogens, occurred more frequently for C. coli and L. monocytogenes than for Salmonella Derby. Composting a digestate reduced the persistence of seeded L. monocytogenes but promoted the maintenance of Salmonella Derby. The effect of NH4+/NH3 on the culturability of C. coli and Salmonella Derby was also shown. The loss of culturability may be the underlying mechanism for the regrowth of pathogens. We have also demonstrated the importance of using molecular tools to monitor pathogens in environmental samples since culture methods may underestimate cell concentration. Our results underline the importance of considering VBNC cells when evaluating the sanitary effect of an anaerobic digestion process and the persistence of pathogens during the storage of

  18. Persistence and Potential Viable but Non-culturable State of Pathogenic Bacteria during Storage of Digestates from Agricultural Biogas Plants

    PubMed Central

    Maynaud, Geraldine; Pourcher, Anne-Marie; Ziebal, Christine; Cuny, Anais; Druilhe, Céline; Steyer, Jean-Philippe; Wéry, Nathalie

    2016-01-01

    Despite the development of on-farm anaerobic digestion as a process for making profitable use of animal by-products, factors leading to the inactivation of pathogenic bacteria during storage of digestates remain poorly described. Here, a microcosm approach was used to evaluate the persistence of three pathogenic bacteria (Salmonella enterica Derby, Campylobacter coli and Listeria monocytogenes) in digestates from farms, stored for later land spreading. Nine samples, including raw digestates, liquid fractions of digestate and composted digestates, were inoculated with each pathogen and maintained for 40 days at 24°C. Concentrations of pathogens were monitored using culture and qPCR methods. The persistence of L. monocytogenes, detected up to 20 days after inoculation, was higher than that of Salmonella Derby, detected for 7–20 days, and of C. coli (not detected after 7 days). In some digestates, the concentration of the pathogens by qPCR assay was several orders of magnitude higher than the concentration of culturable cells, suggesting a potential loss of culturability and induction of Viable but Non-Culturable (VBNC) state. The potential VBNC state which was generally not observed in the same digestate for the three pathogens, occurred more frequently for C. coli and L. monocytogenes than for Salmonella Derby. Composting a digestate reduced the persistence of seeded L. monocytogenes but promoted the maintenance of Salmonella Derby. The effect of NH4+/NH3 on the culturability of C. coli and Salmonella Derby was also shown. The loss of culturability may be the underlying mechanism for the regrowth of pathogens. We have also demonstrated the importance of using molecular tools to monitor pathogens in environmental samples since culture methods may underestimate cell concentration. Our results underline the importance of considering VBNC cells when evaluating the sanitary effect of an anaerobic digestion process and the persistence of pathogens during the storage of

  19. Essential oils against foodborne pathogens and spoilage bacteria in minced meat.

    PubMed

    Barbosa, Lidiane Nunes; Rall, Vera Lucia Mores; Fernandes, Ana Angélica Henrique; Ushimaru, Priscila Ikeda; da Silva Probst, Isabella; Fernandes, Ary

    2009-01-01

    The antimicrobial activity of essential oils of oregano, thyme, basil, marjoram, lemongrass, ginger, and clove was investigated in vitro by agar dilution method and minimal inhibitory concentration (MIC) determination against Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative strains (Escherichia coli and Salmonella Enteritidis). MIC(90%) values were tested against bacterial strains inoculated experimentally in irradiated minced meat and against natural microbiota (aerobic or facultative, mesophilic, and psychrotrophic bacteria) found in minced meat samples. MIC(90%) values ranged from 0.05%v/v (lemongrass oil) to 0.46%v/v (marjoram oil) to Gram-positive bacteria and from 0.10%v/v (clove oil) to 0.56%v/v (ginger oil) to Gram-negative strains. However, the MIC(90%) assessed on minced meat inoculated experimentally with foodborne pathogen strains and against natural microbiota of meat did not show the same effectiveness, and 1.3 and 1.0 were the highest log CFU/g reduction values obtained against tested microorganisms.

  20. Antibacterial activity of caffeine against plant pathogenic bacteria.

    PubMed

    Sledz, Wojciech; Los, Emilia; Paczek, Agnieszka; Rischka, Jacek; Motyka, Agata; Zoledowska, Sabina; Piosik, Jacek; Lojkowska, Ewa

    2015-01-01

    The objective of the present study was to evaluate the antibacterial properties of a plant secondary metabolite - caffeine. Caffeine is present in over 100 plant species. Antibacterial activity of caffeine was examined against the following plant-pathogenic bacteria: Ralstonia solanacearum (Rsol), Clavibacter michiganesis subsp. sepedonicus (Cms), Dickeya solani (Dsol), Pectobacterium atrosepticum (Pba), Pectobacterium carotovorum subsp. carotovorum (Pcc), Pseudomonas syringae pv. tomato (Pst), and Xanthomonas campestris subsp. campestris (Xcc). MIC and MBC values ranged from 5 to 20 mM and from 43 to 100 mM, respectively. Caffeine increased the bacterial generation time of all tested species and caused changes in cell morphology. The influence of caffeine on the synthesis of DNA, RNA and proteins was investigated in cultures of plant pathogenic bacteria with labelled precursors: [(3)H]thymidine, [(3)H]uridine or (14)C leucine, respectively. RNA biosynthesis was more affected than DNA or protein biosynthesis in bacterial cells treated with caffeine. Treatment of Pba with caffeine for 336 h did not induce resistance to this compound. Caffeine application reduced disease symptoms caused by Dsol on chicory leaves, potato slices, and whole potato tubers. The data presented indicate caffeine as a potential tool for the control of diseases caused by plant-pathogenic bacteria, especially under storage conditions. PMID:26307771

  1. Antibacterial activity of caffeine against plant pathogenic bacteria.

    PubMed

    Sledz, Wojciech; Los, Emilia; Paczek, Agnieszka; Rischka, Jacek; Motyka, Agata; Zoledowska, Sabina; Piosik, Jacek; Lojkowska, Ewa

    2015-01-01

    The objective of the present study was to evaluate the antibacterial properties of a plant secondary metabolite - caffeine. Caffeine is present in over 100 plant species. Antibacterial activity of caffeine was examined against the following plant-pathogenic bacteria: Ralstonia solanacearum (Rsol), Clavibacter michiganesis subsp. sepedonicus (Cms), Dickeya solani (Dsol), Pectobacterium atrosepticum (Pba), Pectobacterium carotovorum subsp. carotovorum (Pcc), Pseudomonas syringae pv. tomato (Pst), and Xanthomonas campestris subsp. campestris (Xcc). MIC and MBC values ranged from 5 to 20 mM and from 43 to 100 mM, respectively. Caffeine increased the bacterial generation time of all tested species and caused changes in cell morphology. The influence of caffeine on the synthesis of DNA, RNA and proteins was investigated in cultures of plant pathogenic bacteria with labelled precursors: [(3)H]thymidine, [(3)H]uridine or (14)C leucine, respectively. RNA biosynthesis was more affected than DNA or protein biosynthesis in bacterial cells treated with caffeine. Treatment of Pba with caffeine for 336 h did not induce resistance to this compound. Caffeine application reduced disease symptoms caused by Dsol on chicory leaves, potato slices, and whole potato tubers. The data presented indicate caffeine as a potential tool for the control of diseases caused by plant-pathogenic bacteria, especially under storage conditions.

  2. Involvement of Type IV Pili in Pathogenicity of Plant Pathogenic Bacteria

    PubMed Central

    Burdman, Saul; Bahar, Ofir; Parker, Jennifer K.; De La Fuente, Leonardo

    2011-01-01

    Type IV pili (T4P) are hair-like appendages found on the surface of a wide range of bacteria belonging to the β-, γ-, and δ-Proteobacteria, Cyanobacteria and Firmicutes. They constitute an efficient device for a particular type of bacterial surface motility, named twitching, and are involved in several other bacterial activities and functions, including surface adherence, colonization, biofilm formation, genetic material uptake and virulence. Tens of genes are involved in T4P synthesis and regulation, with the majority of them being generally named pil/fim genes. Despite the multiple functionality of T4P and their well-established role in pathogenicity of animal pathogenic bacteria, relatively little attention has been given to the role of T4P in plant pathogenic bacteria. Only in recent years studies have begun to examine with more attention the relevance of these surface appendages for virulence of plant bacterial pathogens. The aim of this review is to summarize the current knowledge about T4P genetic machinery and its role in the interactions between phytopathogenic bacteria and their plant hosts. PMID:24710288

  3. Alterations of host cell ubiquitination machinery by pathogenic bacteria

    PubMed Central

    Alomairi, Jaafar; Bonacci, Thomas; Ghigo, Eric; Soubeyran, Philippe

    2015-01-01

    Response of immune and non-immune cells to pathogens infections is a very dynamic process. It involves the activation/modulation of many pathways leading to actin remodeling, membrane engulfing, phagocytosis, vesicle trafficking, phagolysosome formation, aiming at the destruction of the intruder. These sophisticated and rapid mechanisms rely on post-translational modifications (PTMs) of key host cells' factors, and bacteria have developed various strategies to manipulate them to favor their survival. Among these important PTMs, ubiquitination has emerged as a major mediator/modulator/regulator of host cells response to infections that pathogens have also learned to use for their own benefit. In this mini-review, we summarize our current knowledge about the normal functions of ubiquitination during host cell infection, and we detail its hijacking by model pathogens to escape clearance and to proliferate. PMID:25774357

  4. Comparative anatomy of gall development on Gypsophila paniculata induced by bacteria with different mechanisms of pathogenicity.

    PubMed

    Chalupowicz, L; Barash, I; Schwartz, M; Aloni, R; Manulis, S

    2006-07-01

    Galls induced on Gypsophila paniculata by Pantoea agglomerans pv. gypsophilae (Pag) and Agrobacterium tumefaciens (At), bacteria with different mechanisms of pathogenicity, were compared morphologically and anatomically. The pathogenicity of Pag is dependent on the presence of an indigenous plasmid that harbors hrp gene cluster, genes encoding Hop virulence proteins and biosynthetic genes for auxin (IAA) and cytokinins (CKs), whereas that of At involves host transformation. The Pag-induced gall was rough, brittle and exhibited limited growth, in contrast to the smooth, firm appearance and continuous growth of the At-induced gall. Anatomical analysis revealed the presence of cells with enlarged nuclei and multiple nucleoli, giant cells and suberin deposition in Pag that were absent from At-induced galls. Although circular vessels were observed in both gall types, they were more numerous and the vascular system was more organized in At. An aerenchymal tissue was observed in the upper part of the galls. Ethylene emission from Pag galls, recorded 6 days after inoculation, was eight times as great as that from non-infected controls. In contrast, a significant decrease in ethylene production was observed in Gypsophila cuttings infected with Pag mutants deficient in IAA and CK production. The results presented are best accounted for by the two pathogens having distinct pathogenicity mechanisms that lead to their differential recognition by the host as non-self (Pag) and self (At).

  5. Differential effects of catecholamines on in vitro growth of pathogenic bacteria

    NASA Technical Reports Server (NTRS)

    Belay, Tesfaye; Sonnenfeld, Gerald

    2002-01-01

    Supplementation of minimal medium inoculated with bacterial cultures with norepinephrine, epinephrine, dopamine, or isoproterenol resulted in marked increases in growth compared to controls. Norepinephrine and dopamine had the greatest enhancing effects on growth of cultures of Pseudomonas aeruginosa and Klebsiella pneumoniae, while epinephrine and isoproterenol also enhanced growth to a lesser extent. The growth of Escherichia coli in the presence of norepinephrine was greater than growth in the presence of the three other neurochemicals used in the study. Growth of Staphylococcus aureus was also enhanced in the presence of norepinephrine, but not to the same degree as was the growth of gram negative bacteria. Addition of culture supernatants from E. coli cultures that had been grown in the presence of norepinephrine was able to enhance the growth of K. pneumoniae. Addition of the culture supernatant fluid culture from E. coli cultures that had been grown in the presence of norepinephrine did not enhance growth of P. aeruginosa or S. aureus. Culture supernatant fluids from bacteria other than E. coli grown in the presence of norepinephrine were not able to enhance the growth of any bacteria tested. The results suggest that catecholamines can enhance growth of pathogenic bacteria, which may contribute to development of pathogenesis; however, there is no uniform effect of catecholamines on bacterial growth.

  6. Detection of bacterial aggregation in cell suspensions treated with pathogenic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The early interaction between plant cells and pathogenic bacteria were studied using tobacco cell suspensions treated with pathogenic and nonpathogenic Pseudomonas species. Previous studies of this system have documented that interactions with pathogens that cause a hypersensitive response on whole...

  7. Modeling the interactions between pathogenic bacteria, bacteriophage and immune response

    NASA Astrophysics Data System (ADS)

    Leung, Chung Yin (Joey); Weitz, Joshua S.

    The prevalence of antibiotic-resistant strains of pathogenic bacteria has led to renewed interest in the use of bacteriophage (phage), or virus that infects bacteria, as a therapeutic agent against bacterial infections. However, little is known about the theoretical mechanism by which phage therapy may work. In particular, interactions between the bacteria, the phage and the host immune response crucially influences the outcome of the therapy. Few models of phage therapy have incorporated all these three components, and existing models suffer from unrealistic assumptions such as unbounded growth of the immune response. We propose a model of phage therapy with an emphasis on nonlinear feedback arising from interactions with bacteria and the immune response. Our model shows a synergistic effect between the phage and the immune response which underlies a possible mechanism for phage to catalyze the elimination of bacteria even when neither the immune response nor phage could do so alone. We study the significance of this effect for different parameters of infection and immune response, and discuss its implications for phage therapy.

  8. Phytostabilization of moderate copper contaminated soils using co-inoculation of Vicia faba with plant growth promoting bacteria.

    PubMed

    Fatnassi, Imen Challougui; Chiboub, Manel; Saadani, Omar; Jebara, Moez; Jebara, Salwa Harzalli

    2015-03-01

    There is a need to conduct research on the selection of microbial isolates from rhizosphere of plants growing on heavy metal contaminated soils for specific restoration programs. This article suggest a consortium of bacteria combining Rhizobium sp. CCNWSX0481, Rhizobium leguminosarum bv. viciae, Enterobacter cloacae and Pseudomonas sp. 2(2010) that was examined for the ability to promote Vicia faba.L. growth when cultivated on the vineyard of soil moderately contaminated with copper. Data showed that inoculation was significant in nodulation; it increases the number and the weight of nodules of 50%. Co-inoculation was also found to positively influence growth and seed yield, through increasing fresh shoot and fresh root weights by 33 and 26%, respectively, and through rising numbers of seed per pod and pods per plant. In contrast, co-inoculation produced a significant reduction of accumulated copper in roots attending 35%, however, the treatment revealed no significant effects on the copper contents in pods and seeds. The tested inoculum could be an option to promote V. faba growth and to enhance soil fertilization in moderate copper contaminated soils. Further studies on the influence of co-inoculation practices on copper migration in soil-plant systems are recommended to acquire more information for evaluation of this legume safety.

  9. The effect of Quercus castaneifolia extract on pathogenic enteric bacteria.

    PubMed

    Bahador, N; Baserisalehi, M

    2011-12-01

    The family of Enterobacteriaceae is a major group of gram negative bacteria, some of these microorganisms are pathogen and could cause disease mainly gastroenteritis. Recently, due to drug resistant nature of these bacteria specially in developing countries treatment of the patient considered as important investigate. Quercus castaneifolia is a native plant of Yasuj province in Iran, which the people who living in this area consume the fruit of this plant for treatment of enteric disease. Hence, the present study was conducted to evaluate the effect of fruit of Q. castaneifolia extract on pathogenic enteric bacteria viz., E. coli, Salmonella typhimurium, Shigella dysenteriae and Yersinia enterocolitica. Antimicrobial susceptibility and minimal inhibitory concentration (MIC) of the extracts were assessed by gel diffusion method and modification of E-test respectively. All the experiments were performed in triplicate and the statistical analysis was carried out on the results. The results obtained from this study indicated that alcoholic extract was shown antimicrobial effect on the microorganisms tested. In addition, S. dysentriae was more sensitive with zone of inhibition 18 mm and MIC value was 2.5 × 10(-4) whereas, E. coli was less sensitive with zone of inhibition 12 mm and MIC value 1 × 10(-2). Salmonella typhimurium and Yersinia enterocolitica showed relatively intermediate susceptibility to the extract with zone of inhibition of 14 mm and MIC value 5 × 10(-3). Overall, Q. castaneifolia may be considered for treatment of the patients suffering from enteric disease.

  10. Inoculation of bats with European Geomyces destructans supports the novel pathogen hypothesis for the origin of white-nose syndrome

    USGS Publications Warehouse

    Warnecke, Lisa; Turner, James M.; Bollinger, Trent K.; Lorch, Jeffrey M.; Misra, Vikram; Cryan, Paul M.; Wibbelt, Gudrun; Blehert, David S.; Willis, Craig K.R.

    2012-01-01

    White-nose syndrome (WNS) is an emerging disease of hibernating bats associated with cutaneous infection by the fungus Geomyces destructans (Gd), and responsible for devastating declines of bat populations in eastern North America. Affected bats appear emaciated and one hypothesis is that they spend too much time out of torpor during hibernation, depleting vital fat reserves required to survive the winter. The fungus has also been found at low levels on bats throughout Europe but without mass mortality. This finding suggests that Gd is either native to both continents but has been rendered more pathogenic in North America by mutation or environmental change, or that it recently arrived in North America as an invader from Europe. Thus, a causal link between Gd and mortality has not been established and the reason for its high pathogenicity in North America is unknown. Here we show that experimental inoculation with either North American or European isolates of Gd causes WNS and mortality in the North American bat, Myotis lucifugus. In contrast to control bats, individuals inoculated with either isolate of Gd developed cutaneous infections diagnostic of WNS, exhibited a progressive increase in the frequency of arousals from torpor during hibernation, and were emaciated after 3–4 mo. Our results demonstrate that altered torpor-arousal cycles underlie mortality from WNS and provide direct evidence that Gd is a novel pathogen to North America from Europe.

  11. Inoculation of bats with European Geomyces destructans supports the novel pathogen hypothesis for the origin of white-nose syndrome.

    PubMed

    Warnecke, Lisa; Turner, James M; Bollinger, Trent K; Lorch, Jeffrey M; Misra, Vikram; Cryan, Paul M; Wibbelt, Gudrun; Blehert, David S; Willis, Craig K R

    2012-05-01

    White-nose syndrome (WNS) is an emerging disease of hibernating bats associated with cutaneous infection by the fungus Geomyces destructans (Gd), and responsible for devastating declines of bat populations in eastern North America. Affected bats appear emaciated and one hypothesis is that they spend too much time out of torpor during hibernation, depleting vital fat reserves required to survive the winter. The fungus has also been found at low levels on bats throughout Europe but without mass mortality. This finding suggests that Gd is either native to both continents but has been rendered more pathogenic in North America by mutation or environmental change, or that it recently arrived in North America as an invader from Europe. Thus, a causal link between Gd and mortality has not been established and the reason for its high pathogenicity in North America is unknown. Here we show that experimental inoculation with either North American or European isolates of Gd causes WNS and mortality in the North American bat, Myotis lucifugus. In contrast to control bats, individuals inoculated with either isolate of Gd developed cutaneous infections diagnostic of WNS, exhibited a progressive increase in the frequency of arousals from torpor during hibernation, and were emaciated after 3-4 mo. Our results demonstrate that altered torpor-arousal cycles underlie mortality from WNS and provide direct evidence that Gd is a novel pathogen to North America from Europe. PMID:22493237

  12. Molecular assessment of inoculated and indigenous bacteria in biofilms from a pilot-scale perchlorate-reducing bioreactor.

    PubMed

    Zhang, H; Logan, B E; Regan, J M; Achenbach, L A; Bruns, M A

    2005-04-01

    Bioremediation of perchlorate-contaminated groundwater can occur via bacterial reduction of perchlorate to chloride. Although perchlorate reduction has been demonstrated in bacterial pure cultures, little is known about the efficacy of using perchlorate-reducing bacteria as inoculants for bioremediation in the field. A pilot-scale, fixed-bed bioreactor containing plastic support medium was used to treat perchlorate-contaminated groundwater at a site in Southern California. The bioreactor was inoculated with a field-grown suspension of the perchlorate-respiring bacterium Dechlorosoma sp. strain KJ and fed groundwater containing indigenous bacteria and a carbon source amendment. Because the reactor was flushed weekly to remove accumulated biomass, only bacteria capable of growing in biofilms in the reactor were expected to survive. After 26 days of operation, perchlorate was not detected in bioreactor effluent. Perchlorate remained undetected by ion chromatography (detection limit 4 mug L(-1)) during 6 months of operation, after which the reactor was drained. Plastic medium was subsampled from top, middle, and bottom locations of the reactor for shipment on blue ice and storage at -80 degrees C prior to analysis. Microbial community DNA was extracted from successive washes of thawed biofilm material for PCR-based community profiling by 16S-23S ribosomal intergenic spacer analysis (RISA). No DNA sequences characteristic of strain KJ were recovered from any RISA bands. The most intense bands yielded DNA sequences with high similarities to Dechloromonas spp., a closely related but different genus of perchlorate-respiring bacteria. Additional sequences from RISA profiles indicated presence of representatives of the low G+C gram-positive bacteria and the Cytophaga-Flavobacterium-Bacteroides group. Confocal scanning laser microscopy and fluorescence in situ hybridization (FISH) were also used to examine biofilms using genus-specific 16S ribosomal RNA probes. FISH was more

  13. Lactic acid as a potential decontaminant of selected foodborne pathogenic bacteria in shrimp (Penaeus merguiensis de Man).

    PubMed

    Shirazinejad, Alireza; Ismail, Noryati; Bhat, Rajeev

    2010-12-01

    Fresh raw shrimps were dipped for 10, 20, and 30 min at room temperature (25°C ± 1°C) in lactic acid (LA; 1.5%, 3.0%, v/v) to evaluate their antipathogenic effects against Vibrio cholerae, Vibrio parahaemolyticus, Salmonella entreitidis, and Escherichia coli O157:H7 inoculated at a level of 10(5) CFU/g. Significant reductions in the population of all these pathogenic bacteria were recorded after dipping treatments, which were correlated to the corresponding LA concentrations and treatment time. With respect to the microbial quality, 3.0% LA treatment for 10 min was acceptable in reducing the pathogenic bacteria. Additionally, sensory evaluation results revealed a 10-min dip in 3.0% LA to be more acceptable organoleptically compared with 20 and 30 min of treatments. Results of the present study are envisaged to be useful for commercial applications for effective decontamination of shrimp.

  14. Effect of Simultaneous Inoculation with Yeast and Bacteria on Fermentation Kinetics and Key Wine Parameters of Cool-Climate Chardonnay

    PubMed Central

    Jussier, Delphine; Dubé Morneau, Amélie; Mira de Orduña, Ramón

    2006-01-01

    Inoculating grape musts with wine yeast and lactic acid bacteria (LAB) concurrently in order to induce simultaneous alcoholic fermentation (AF) and malolactic fermentation (MLF) can be an efficient alternative to overcome potential inhibition of LAB in wines because of high ethanol concentrations and reduced nutrient content. In this study, the simultaneous inoculation of yeast and LAB into must was compared with a traditional vinification protocol, where MLF was induced after completion of AF. For this, two suitable commercial yeast-bacterium combinations were tested in cool-climate Chardonnay must. The time courses of glucose and fructose, acetaldehyde, several organic acids, and nitrogenous compounds were measured along with the final values of other key wine parameters. Sensory evaluation was done after 12 months of storage. The current study could not confirm a negative impact of simultaneous AF/MLF on fermentation success and kinetics or on final wine parameters. While acetic acid concentrations were slightly increased in wines after simultaneous AF/MLF, the differences were of neither practical nor legal significance. No statistically significant differences were found with regard to the final values of pH or total acidity and the concentrations of ethanol, acetaldehyde, glycerol, citric and lactic acids, and the nitrogen compounds arginine, ammonia, urea, citrulline, and ornithine. Sensory evaluation by a semiexpert panel confirmed the similarity of the wines. However, simultaneous inoculation led to considerable reductions in overall fermentation durations. Furthermore, differences of physiological and microbiological relevance were found. Specifically, we report the vinification of “super-dry” wines devoid of glucose and fructose after simultaneous inoculation of yeast and bacteria. PMID:16391046

  15. Human pathogenic bacteria, fungi, and viruses in Drosophila

    PubMed Central

    Panayidou, Stavria; Ioannidou, Eleni; Apidianakis, Yiorgos

    2014-01-01

    Drosophila has been the invertebrate model organism of choice for the study of innate immune responses during the past few decades. Many Drosophila–microbe interaction studies have helped to define innate immunity pathways, and significant effort has been made lately to decipher mechanisms of microbial pathogenesis. Here we catalog 68 bacterial, fungal, and viral species studied in flies, 43 of which are relevant to human health. We discuss studies of human pathogens in flies revealing not only the elicitation and avoidance of immune response but also mechanisms of tolerance, host tissue homeostasis, regeneration, and predisposition to cancer. Prominent among those is the emerging pattern of intestinal regeneration as a defense response induced by pathogenic and innocuous bacteria. Immunopathology mechanisms and many microbial virulence factors have been elucidated, but their relevance to human health conventionally necessitates validation in mammalian models of infection. PMID:24398387

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Top 10 plant pathogenic bacteria in molecular plant pathology.

    PubMed

    Mansfield, John; Genin, Stephane; Magori, Shimpei; Citovsky, Vitaly; Sriariyanum, Malinee; Ronald, Pamela; Dow, Max; Verdier, Valérie; Beer, Steven V; Machado, Marcos A; Toth, Ian; Salmond, George; Foster, Gary D

    2012-08-01

    Many plant bacteriologists, if not all, feel that their particular microbe should appear in any list of the most important bacterial plant pathogens. However, to our knowledge, no such list exists. The aim of this review was to survey all bacterial pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate the bacterial pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 458 votes from the international community, and allowed the construction of a Top 10 bacterial plant pathogen list. The list includes, in rank order: (1) Pseudomonas syringae pathovars; (2) Ralstonia solanacearum; (3) Agrobacterium tumefaciens; (4) Xanthomonas oryzae pv. oryzae; (5) Xanthomonas campestris pathovars; (6) Xanthomonas axonopodis pathovars; (7) Erwinia amylovora; (8) Xylella fastidiosa; (9) Dickeya (dadantii and solani); (10) Pectobacterium carotovorum (and Pectobacterium atrosepticum). Bacteria garnering honourable mentions for just missing out on the Top 10 include Clavibacter michiganensis (michiganensis and sepedonicus), Pseudomonas savastanoi and Candidatus Liberibacter asiaticus. This review article presents a short section on each bacterium in the Top 10 list and its importance, with the intention of initiating discussion and debate amongst the plant bacteriology community, as well as laying down a benchmark. It will be interesting to see, in future years, how perceptions change and which bacterial pathogens enter and leave the Top 10. PMID:22672649

  18. Molecular basis of metronidazole resistance in pathogenic bacteria and protozoa.

    PubMed

    Land, Kirkwood M.; Johnson, Patricia J.

    1999-10-01

    The molecular basis of metronidazole resistance has been examined in anaerobic bacteria, such as Bacteroides, Clostridium, and Helicobacter, and anaerobic parasitic protists such as Giardia, Entamoeba, and trichomonads. A variety of enzymatic and cellular alterations have been shown to correlate with metronidazole susceptibility in these pathogens; however, a common theme has been revealed. Resistant cells are typically deficient in drug activation. The frequent correlation between metronidazole resistance and ineffective drug activation suggests that drug resistance is the result of modification of proteins involved in drug activation. Copyright 1999 Harcourt Publishers Ltd.

  19. Selective antimicrobial activity of maggots against pathogenic bacteria.

    PubMed

    Jaklic, Domen; Lapanje, Ales; Zupancic, Klemen; Smrke, Dragica; Gunde-Cimerman, Nina

    2008-05-01

    Maggot therapy, also known as biosurgery, is an ancient method for the healing of chronic infected wounds. Although clinicians have reported on the beneficial activities of the Lucilia sericata larvae that have been used for healing chronic wounds, the selectivity of this therapy against the different pathogenic micro-organisms that are found in chronic wounds has never been analysed. In the present study, we have investigated the in vitro activities of larval excreta/secreta both against selected bacterial strains that frequently occur in chronically infected wounds, and against bacteria isolated directly from the larvae and their excreta/secreta. Additionally, the antibacterial activities were investigated in in vivo studies, by comparing bacterial diversity in wounds before and after the application of L. sericata larvae. In conclusion, larval therapy is highly recommended, particularly for the treatment of wounds infected with Gram-positive bacteria, like Staphylococcus aureus, but less so for wounds infected with Gram-negative bacteria, especially Proteus spp. and Pseudomonas spp. strains. Bacteria from the genus Vagococcus were resistant to the maggot excreta/secreta.

  20. Endobiotic bacteria and their pathogenic potential in cnidarian tentacles

    NASA Astrophysics Data System (ADS)

    Schuett, Christian; Doepke, Hilke

    2010-09-01

    Endobiotic bacteria colonize the tentacles of cnidaria. This paper provides first insight into the bacterial spectrum and its potential of pathogenic activities inside four cnidarian species. Sample material originating from Scottish waters comprises the jellyfish species Cyanea capillata and C. lamarckii, hydrozoa Tubularia indivisa and sea anemone Sagartia elegans. Mixed cultures of endobiotic bacteria, pure cultures selected on basis of haemolysis, but also lyophilized samples were prepared from tentacles and used for DGGE-profiling with subsequent phylogenetic analysis of 16S rDNA fragments. Bacteria were detected in each of the cnidarian species tested. Twenty-one bacterial species including four groups of closely related organisms were found in culture material. The species within these groups could not be differentiated from each other (one group of Pseudoalteromonas spp., two groups of Shewanella spp., one group of Vibrio spp.). Each of the hosts exhibits a specific endobacterial spectrum. Solely Cyanea lamarckii harboured Moritella viscosa. Only in Cyanea capillata, members of the Shewanella group #2 and the species Pseudoalteromonas arctica, Shewanella violacea, Sulfitobacter pontiacus and Arcobacter butzleri were detected. Hydrozoa Tubularia indivisa provided an amazingly wide spectrum of nine bacterial species. Exclusively, in the sea anemone Sagartia elegans, the bacterial species P. aliena was found. Overall eleven bacterial species detected were described recently as novel species. Four 16S rDNA fragments generated from lyophilized material displayed extremely low relationship to their next neighbours. These organisms are regarded as members of the endobiotic “terra incognita”. Since the origin of cnidarian toxins is unclear, the possible pathogenic activity of endobiotic bacteria has to be taken into account. Literature data show that their next neighbours display an interesting diversity of haemolytic, septicaemic and necrotic actions including

  1. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks

    PubMed Central

    2013-01-01

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations. PMID:23876184

  2. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks.

    PubMed

    Pantin-Jackwood, Mary; Swayne, David E; Smith, Diane; Shepherd, Eric

    2013-07-22

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations.

  3. Fermentation quality and chemical composition of shrub silage treated with lactic acid bacteria inoculants and cellulase additives.

    PubMed

    Sun, Qizhong; Gao, Fengqin; Yu, Zhu; Tao, Ya; Zhao, Shufen; Cai, Yimin

    2012-04-01

    Effects of lactic acid bacteria (LAB) inoculants and cellulase additives on fermentation quality and chemical compositions of shrub silages were studied by using a small-scale fermentation system. Two LAB inoculants of Qingbao (Lactobacillus plantarum, Pediococcus acidilacticii, Lactobacillus casei and Clostridium phage) and Caihe (Lactobacillus plantarum, Lactobacillus brevis and Pediococcus acidilactici) and a commercial cellulase made from Trichoderma reesei were used as additives for intermediate pea-shrub, rush bushclover, arborescent ceratoides and shrubby silage preparation. The crude protein, neutral detergent fiber and water-soluble carbohydrate contents of the four shrub materials were 10.1-14.2, 62.6-67.2 and 1.9-3.5% on a dry matter basis, respectively. All shrub silages had pH 3.40-4.43, ammonia-N 0.1-0.2% g/kg and lactic acid 1.3-2.9% on a fresh matter basis. The silage quality of LAB-inoculated silages did not have a greater effect than control silages, except shrubby silage preparation. Silages treated with the cellulase, the pH of rush bushclover and shrubby sweetvetch silage were significantly (P < 0.05) lower and the lactic acid content were significantly (P < 0.05) higher than the control silages. The results confirmed that shrub contained a relatively high content of crude protein; its silages can be preserved in good quality, and they are new potential resources for livestock feed. PMID:22515690

  4. Fluorimetric detection of pathogenic bacteria using magnetic carbon dots.

    PubMed

    Bhaisare, Mukesh Lavkush; Gedda, Gangaraju; Khan, M Shahnawaz; Wu, Hui-Fen

    2016-05-12

    A novel and facile approach of pathogenic bacteria detection, which utilizes fluorescent sensing and bacteria capture with Magnetic carbon dots (Mag-CDs), was proposed in this work. Magnetic nanoparticles were synthesized and then decorated with C-dots, and further functionalized with amine groups (chitosan). In this way, bacteria were strongly anchored on the hybrid material Mag-CDs for highly sensitive fluorescent detection. The Mag-CDs were characterized by UV-vis, FT-IR spectra, TEM images, XRD, and EDX. The characterizations validate the fabrication of amine-Mag-CDs and the promising applications of this material. Fluorescence spectroscope and MALDI-MS were used for the detection and identification of bacterial strains, respectively. The limit of detection for Staphylococcus aureus and Escherichia coli was found to be 3 × 10(2) and 3.5 × 10(2) cfu mL(-1), respectively. With these encouraging results, it is expected that it would open revenues for promising applications of Mag-CDs nanomaterial.

  5. Fluorimetric detection of pathogenic bacteria using magnetic carbon dots.

    PubMed

    Bhaisare, Mukesh Lavkush; Gedda, Gangaraju; Khan, M Shahnawaz; Wu, Hui-Fen

    2016-05-12

    A novel and facile approach of pathogenic bacteria detection, which utilizes fluorescent sensing and bacteria capture with Magnetic carbon dots (Mag-CDs), was proposed in this work. Magnetic nanoparticles were synthesized and then decorated with C-dots, and further functionalized with amine groups (chitosan). In this way, bacteria were strongly anchored on the hybrid material Mag-CDs for highly sensitive fluorescent detection. The Mag-CDs were characterized by UV-vis, FT-IR spectra, TEM images, XRD, and EDX. The characterizations validate the fabrication of amine-Mag-CDs and the promising applications of this material. Fluorescence spectroscope and MALDI-MS were used for the detection and identification of bacterial strains, respectively. The limit of detection for Staphylococcus aureus and Escherichia coli was found to be 3 × 10(2) and 3.5 × 10(2) cfu mL(-1), respectively. With these encouraging results, it is expected that it would open revenues for promising applications of Mag-CDs nanomaterial. PMID:27114224

  6. Impact of Inoculation Protocols, Salinity, and pH on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) and Survival of PAH-Degrading Bacteria Introduced into Soil

    PubMed Central

    Kästner, Matthias; Breuer-Jammali, Maren; Mahro, Bernd

    1998-01-01

    Degradation of polycyclic aromatic hydrocarbons (PAHs) and survival of bacteria in soil was investigated by applying different inoculation protocols. The soil was inoculated with Sphingomonas paucimobilis BA 2 and strain BP 9, which are able to degrade anthracene and pyrene, respectively. CFU of soil bacteria and of the introduced bacteria were monitored in native and sterilized soil at different pHs. Introduction with mineral medium inhibited PAH degradation by the autochthonous microflora and by the strains tested. After introduction with water (without increase of the pore water salinity), no inhibition of the autochthonous microflora was observed and both strains exhibited PAH degradation. PMID:9435090

  7. Assessing the efficacy of co-inoculation of wheat seedlings with the associative bacteria Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245.

    PubMed

    Yegorenkova, Irina V; Tregubova, Kristina V; Burygin, Gennady L; Matora, Larisa Y; Ignatov, Vladimir V

    2016-03-01

    Co-inoculation of associative bacteria, which have high nitrogen-fixing activity, tolerance for environmental conditions, and the ability to compete with the natural microflora, is used widely to enhance the growth and yields of agricultural plants. We evaluated the ability of 2 co-inoculated plant-growth-promoting rhizobacteria, Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245, to colonize roots of wheat (Triticum aestivum L. 'Saratovskaya 29') seedlings, and we assessed the morphometric parameters of wheat early in its development. Analysis by ELISA with polyclonal antibodies raised against the exopolysaccharide of P. polymyxa 1465 and the lipopolysaccharide of A. brasilense Sp245 demonstrated that the root-colonizing activity of A. brasilense was higher when the bacterium was co-inoculated with P. polymyxa than when it was inoculated singly. Immunofluorescence microscopy with Alexa Fluor 532-labeled antibodies revealed sites of attachment of co-inoculated P. polymyxa and A. brasilense and showed that the 2 bacteria colonized similar regions of the roots. Co-inoculation exerted a negative effect on wheat seedling development, inhibiting root length by 17.6%, total root weight by 11%, and total shoot weight by 12%. Under certain conditions, dual inoculation of wheat may prove ineffective, apparently owing to the competition between the rhizobacteria for colonization sites on the plant roots. The findings from this study may aid in developing techniques for mixed bacterial inoculation of cultivated plants. PMID:26863134

  8. Assessing the efficacy of co-inoculation of wheat seedlings with the associative bacteria Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245.

    PubMed

    Yegorenkova, Irina V; Tregubova, Kristina V; Burygin, Gennady L; Matora, Larisa Y; Ignatov, Vladimir V

    2016-03-01

    Co-inoculation of associative bacteria, which have high nitrogen-fixing activity, tolerance for environmental conditions, and the ability to compete with the natural microflora, is used widely to enhance the growth and yields of agricultural plants. We evaluated the ability of 2 co-inoculated plant-growth-promoting rhizobacteria, Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245, to colonize roots of wheat (Triticum aestivum L. 'Saratovskaya 29') seedlings, and we assessed the morphometric parameters of wheat early in its development. Analysis by ELISA with polyclonal antibodies raised against the exopolysaccharide of P. polymyxa 1465 and the lipopolysaccharide of A. brasilense Sp245 demonstrated that the root-colonizing activity of A. brasilense was higher when the bacterium was co-inoculated with P. polymyxa than when it was inoculated singly. Immunofluorescence microscopy with Alexa Fluor 532-labeled antibodies revealed sites of attachment of co-inoculated P. polymyxa and A. brasilense and showed that the 2 bacteria colonized similar regions of the roots. Co-inoculation exerted a negative effect on wheat seedling development, inhibiting root length by 17.6%, total root weight by 11%, and total shoot weight by 12%. Under certain conditions, dual inoculation of wheat may prove ineffective, apparently owing to the competition between the rhizobacteria for colonization sites on the plant roots. The findings from this study may aid in developing techniques for mixed bacterial inoculation of cultivated plants.

  9. RARE OCCURRENCE OF HETEROTROPHIC BACTERIA WITH PATHOGENIC POTENTIAL IN POTABLE WATER

    EPA Science Inventory

    Since the discovery of Legionella pneumophila, an opportunistic pathogen that is indigenous to water, microbiologists have speculated that there may be other opportunistic pathogens among the numerous heterotrophic bacteria found in potable water. The USEPA developed a series of...

  10. Microbiological investigation of Raphanus sativus L. grown hydroponically in nutrient solutions contaminated with spoilage and pathogenic bacteria.

    PubMed

    Settanni, Luca; Miceli, Alessandro; Francesca, Nicola; Cruciata, Margherita; Moschetti, Giancarlo

    2013-01-01

    The survival of eight undesired (spoilage/pathogenic) food related bacteria (Citrobacter freundii PSS60, Enterobacter spp. PSS11, Escherichia coli PSS2, Klebsiella oxytoca PSS82, Serratia grimesii PSS72, Pseudomonas putida PSS21, Stenotrophomonas maltophilia PSS52 and Listeria monocytogenes ATCC 19114(T)) was investigated in mineral nutrient solution (MNS) during the crop cycle of radishes (Raphanus sativus L.) cultivated in hydroponics in a greenhouse. MNSs were microbiologically analyzed weekly by plate count. The evolution of the pure cultures was also evaluated in sterile MNS in test tubes. The inoculated trials contained an initial total mesophilic count (TMC) ranging between 6.69 and 7.78Log CFU/mL, while non-sterile and sterile control trials showed levels of 4.39 and 0.97Log CFU/mL, respectively. In general, all inoculated trials showed similar levels of TMC in MNS during the experimentation, even though the levels of the inoculated bacteria decreased. The presence of the inoculums was ascertained by randomly amplified polymorphic DNA (RAPD) analysis applied on the isolates collected at 7-day intervals. At harvest, MNSs were also analyzed by denaturing gradient gel electrophoresis (DGGE). The last analysis, except P. putida PSS21 in the corresponding trial, did not detect the other bacteria, but confirmed that pseudomonads were present in un-inoculated MNSs. Despite the high counts detected (6.44 and 7.24CFU/g), only C. freundii PSS60, Enterobacter spp. PSS11 and K. oxytoca PSS82 were detected in radishes in a living form, suggesting their internalization.

  11. Evolutionary aspects of collective motility in pathogenic bacteria

    NASA Astrophysics Data System (ADS)

    Deforet, Maxime; Xavier, Joao

    Pseudomonas aeruginosa is a pathogenic bacteria that can use its single polar flagellum to swim through liquids. It can move collectively over semisolid surfaces, a behavior called swarming. It can also settle and form surface-attached communities called biofilms that protect them from antibiotics. The transition from single motility (swimming) to collective motility (swarming) is biologically relevant as it enables exploring environments that a single bacterium cannot explore on its own. It is also clinically relevant since swarming and biofilm formation are thought to be antagonistic. We investigate the mechanisms of bacterial collective motility using a multidisciplinary approach that combines mathematical modeling, quantitative experiments, and microbial genetics. We aim to identify how these mechanisms may evolve under the selective pressure of population expansion, and consequently reinforce or hinder collective motility. In particular, we clarify the role of growth rate and motility in invasive populations.

  12. Partial denture metal framework may harbor potentially pathogenic bacteria

    PubMed Central

    Bernardes, Luciano Angelo de Souza; Gomes, Sabrina Carvalho; Silva, Alecsandro Moura

    2015-01-01

    PURPOSE The aim of this study was to characterize and compare bacterial diversity on the removable partial denture (RPD) framework over time. MATERIALS AND METHODS This descriptive pilot study included five women who were rehabilitated with free-end mandibular RPD. The biofilm on T-bar clasps were collected 1 week (t1) and 4 months (t2) after the RPD was inserted (t0). Bacterial 16S rDNA was extracted and PCR amplified. Amplicons were cloned; clones were submitted to cycle sequencing, and sequences were compared with GenBank (98% similarity). RESULTS A total of 180 sequences with more than 499 bp were obtained. Two phylogenetic trees with 84 (t1) and 96 (t2) clones represented the bacteria biofilm at the RPD. About 93% of the obtained phylotypes fell into 25 known species for t1 and 17 for t2, which were grouped in 5 phyla: Firmicutes (t1=82%; t2=60%), Actinobacteria (t1=5%; t2=10%), Bacteroidetes (t1=2%; t2=6%), Proteobacteria (t1=10%; t2=15%) and Fusobacteria (t1=1%; t2=8%). The libraries also include 3 novel phylotypes for t1 and 11 for t2. Library t2 differs from t1 (P=.004); t1 is a subset of the t2 (P=.052). Periodontal pathogens, such as F. nucleatum, were more prevalent in t2. CONCLUSION The biofilm composition of the RPD metal clasps changed along time after RPD wearing. The RPD framework may act as a reservoir for potentially pathogenic bacteria and the RPD wearers may benefit from regular follow-up visits and strategies on prosthesis-related oral health instructions. PMID:26816577

  13. Effect of low-dose gaseous ozone on pathogenic bacteria

    PubMed Central

    2012-01-01

    Background Treatment of chronically infected wounds is a challenge, and bacterial environmental contamination is a growing issue in infection control. Ozone may have a role in these situations. The objective of this study was to determine whether a low dose of gaseous ozone/oxygen mixture eliminates pathogenic bacteria cultivated in Petri dishes. Methods A pilot study with 6 bacterial strains was made using different concentrations of ozone in an ozone-oxygen mixture to determine a minimally effective dose that completely eliminated bacterial growth. The small and apparently bactericidal gaseous dose of 20 μg/mL ozone/oxygen (1:99) mixture, applied for 5min under atmospheric pressure was selected. In the 2nd phase, eight bacterial strains with well characterized resistance patterns were evaluated in vitro using agar-blood in adapted Petri dishes (105 bacteria/dish). The cultures were divided into 3 groups: 1- ozone-oxygen gaseous mixture containing 20 μg of O3/mL for 5 min; 2- 100% oxygen for 5 min; 3- baseline: no gas was used. Results The selected ozone dose was applied to the following eight strains: Escherichia coli, oxacillin-resistant Staphylococcus aureus, oxacillin-susceptible Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii, Acinetobacter baumannii susceptible only to carbapenems, and Pseudomonas aeruginosa susceptible to imipenem and meropenem. All isolates were completely inhibited by the ozone-oxygen mixture while growth occurred in the other 2 groups. Conclusion A single topical application by nebulization of a low ozone dose completely inhibited the growth of all potentially pathogenic bacterial strains with known resistance to antimicrobial agents. PMID:23249441

  14. Leprous lesion presents enrichment of opportunistic pathogenic bacteria.

    PubMed

    Silva, Paulo Es; Costa, Patrícia S; Ávila, Marcelo P; Suhadolnik, Maria Luíza S; Reis, Mariana P; Salgado, Ana Paula C; Lima, Mário Fr; Chartone-Souza, Edmar; Nascimento, Andréa Ma

    2015-01-01

    Leprosy is a chronic infectious disease that remains a major challenge to public health in endemic countries. Increasing evidence has highlighted the importance of microbiota for human general health and, as such, the study of skin microbiota is of interest. But while studies are continuously revealing the complexity of human skin microbiota, the microbiota of leprous cutaneous lesions has not yet been characterized. Here we used Sanger and massively parallel small sub-unit rRNA (SSU) rRNA gene sequencing to characterize the microbiota of leprous lesions, and studied how it differs from the bacterial skin composition of healthy individuals previously described in the literature. Taxonomic analysis of leprous lesions revealed main four phyla: Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, with Proteobacteria presenting the highest diversity. There were considerable differences in the distribution of Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria, with the first two phyla enriched and the other markedly diminished in the leprous lesions, when compared with healthy skin. Propionibacterium, Corynebacterium and Staphylococcus, resident and abundant in healthy skin, were underrepresented in skin from leprous lesions. Most of the taxa found in skin from leprous lesions are not typical in human skin and potentially pathogenic, with the Burkholderia, Pseudomonas and Bacillus genera being overrepresented. Our data suggest significant shifts of the microbiota with emergence and competitive advantage of potentially pathogenic bacteria over skin resident taxa. PMID:25918684

  15. Function of site-2 proteases in bacteria and bacterial pathogens

    PubMed Central

    Schneider, Jessica S.; Glickman, Michael S.

    2014-01-01

    Site-2 Proteases (S2Ps) are a class of intramembrane metalloproteases named after the founding member of this protein family, human S2P, which cleaves Sterol Regulatory Element Binding Proteins which control cholesterol and fatty acid biosynthesis. S2Ps are widely distributed in bacteria and participate in diverse pathways that control such diverse functions as membrane integrity, sporulation, lipid biosynthesis, pheromone production, virulence, and others. The most common signaling mechanism mediated by S2Ps is the coupled degradation of transmembrane anti-Sigma factors to activate ECF Sigma factor regulons. However, additional signaling mechanisms continue to emerge as more prokaryotic S2Ps are characterized, including direct proteolysis of membrane embedded transcription factors and proteolysis of non-transcriptional membrane proteins or membrane protein remnants. In this review we seek to comprehensively review the functions of S2Ps in bacteria and bacterial pathogens and attempt to organize these proteases into conceptual groups that will spur further study. PMID:24099002

  16. Bronchointerstitial pneumonia in guinea pigs following inoculation with H5N1 high pathogenicity avian influenza virus.

    PubMed

    Kwon, Y K; Lipatov, A S; Swayne, D E

    2009-01-01

    The H5N1 high-pathogenicity avian influenza (HPAI) viruses have caused widespread disease of poultry in Asia, Africa and the Middle East, and sporadic human infections. The guinea pig model has been used to study human H3N2 and H1N1 influenza viruses, but knowledge is lacking on H5N1 HPAI virus infections. Guinea pigs were inoculated intranasally or intragastrically with A/Vietnam/1203/04 (VN/04) or A/Muscovy duck/Vietnam/209/05 (MDk/VN/05) viruses. Mild listlessness was seen at 2 and 3 days postinoculation (DPI) in guinea pigs inoculated intranasally with VN/04 virus. At 5 DPI, the guinea pigs had bronchointerstitial pneumonia and virus was identified in bronchiolar epithelium and alveolar macrophages. Virus was isolated from the lungs but was lacking from other organs. Minimal lung lesions were seen in intranasal MDk/VN/06 group and virus was not detected, but serologic evidence of infection was observed. Intragastric exposure failed to produce infection or lesions with either virus. The localized respiratory disease in guinea pigs with H5N1 viruses was very similar to that of H3N2 and H1N1 influenza in humans and was less severe than reported for H5N1 human cases.

  17. Inoculating poultry manure with companion bacteria influences growth and development of black soldier fly (Diptera: Stratiomyidae) larvae.

    PubMed

    Yu, Guohui; Cheng, Ping; Chen, Yanhong; Li, Yongjian; Yang, Zihong; Chen, Yuanfeng; Tomberlin, Jeffery K

    2011-02-01

    The growth and development of black soldier fly, Hermetia illucens (L.), larvae fed chicken manure inoculated with bacteria isolated from black soldier fly larvae and associated larval feed was evaluated. Four strains of Bacillus subtilis were evaluated. B. subtilis strains S15, S16, S19, were isolated from the gut of black soldier fly larvae. B. natto strain D1 was isolated from the diet fed to black soldier fly larvae. These bacteria were added individually into nonsterile 200 g fresh hen manure at 10(6) cfu/g and homogenized. Treated manure was then inoculated with 4-d old black soldier fly larvae. Prepupal weight ranged from 0.0606 g in the control to 0.0946 g in manure treated with the S15 strain. Larval survivorship to the prepupal stage in all treatments ranged from 98.00 ± 2.65% to 99.33 ± 1.15%. Prepupal survivorship to the pupal stage ranged from 91.92 ± 1.87% to 97.95 ± 1.03%. Adult emergence from the pupal stage did not significantly (P < 0.05) differ across treatments and ranged from 98.95 ± 1.82% to 100.00 ± 0.00%. Adult body length resulting from the larvae in each of the treatments was significantly greater than those from the control. Longevity of adults did not differ significantly between treatments. Time from hatching to the development of the first pupa did not differ significantly across treatments; however, development time from hatching to 90% reaching the prepupual stage was significantly different between treatments and ranged from 29.00 ± 1.00 d to 34.33 ± 3.51 d. Development time from hatching to 90% reaching the adult stages was significantly different between treatments. Our results demonstrate that inoculating poultry manure with bacteria from black soldier fly larvae influences the growth and development of conspecific larvae feeding on the manure. PMID:22182608

  18. Inoculating poultry manure with companion bacteria influences growth and development of black soldier fly (Diptera: Stratiomyidae) larvae.

    PubMed

    Yu, Guohui; Cheng, Ping; Chen, Yanhong; Li, Yongjian; Yang, Zihong; Chen, Yuanfeng; Tomberlin, Jeffery K

    2011-02-01

    The growth and development of black soldier fly, Hermetia illucens (L.), larvae fed chicken manure inoculated with bacteria isolated from black soldier fly larvae and associated larval feed was evaluated. Four strains of Bacillus subtilis were evaluated. B. subtilis strains S15, S16, S19, were isolated from the gut of black soldier fly larvae. B. natto strain D1 was isolated from the diet fed to black soldier fly larvae. These bacteria were added individually into nonsterile 200 g fresh hen manure at 10(6) cfu/g and homogenized. Treated manure was then inoculated with 4-d old black soldier fly larvae. Prepupal weight ranged from 0.0606 g in the control to 0.0946 g in manure treated with the S15 strain. Larval survivorship to the prepupal stage in all treatments ranged from 98.00 ± 2.65% to 99.33 ± 1.15%. Prepupal survivorship to the pupal stage ranged from 91.92 ± 1.87% to 97.95 ± 1.03%. Adult emergence from the pupal stage did not significantly (P < 0.05) differ across treatments and ranged from 98.95 ± 1.82% to 100.00 ± 0.00%. Adult body length resulting from the larvae in each of the treatments was significantly greater than those from the control. Longevity of adults did not differ significantly between treatments. Time from hatching to the development of the first pupa did not differ significantly across treatments; however, development time from hatching to 90% reaching the prepupual stage was significantly different between treatments and ranged from 29.00 ± 1.00 d to 34.33 ± 3.51 d. Development time from hatching to 90% reaching the adult stages was significantly different between treatments. Our results demonstrate that inoculating poultry manure with bacteria from black soldier fly larvae influences the growth and development of conspecific larvae feeding on the manure.

  19. FISHing for bacteria in food--a promising tool for the reliable detection of pathogenic bacteria?

    PubMed

    Rohde, Alexander; Hammerl, Jens Andre; Appel, Bernd; Dieckmann, Ralf; Al Dahouk, Sascha

    2015-04-01

    Foodborne pathogens cause millions of infections every year and are responsible for considerable economic losses worldwide. The current gold standard for the detection of bacterial pathogens in food is still the conventional cultivation following standardized and generally accepted protocols. However, these methods are time-consuming and do not provide fast information about food contaminations and thus are limited in their ability to protect consumers in time from potential microbial hazards. Fluorescence in situ hybridization (FISH) represents a rapid and highly specific technique for whole-cell detection. This review aims to summarize the current data on FISH-testing for the detection of pathogenic bacteria in different food matrices and to evaluate its suitability for the implementation in routine testing. In this context, the use of FISH in different matrices and their pretreatment will be presented, the sensitivity and specificity of FISH tests will be considered and the need for automation shall be discussed as well as the use of technological improvements to overcome current hurdles for a broad application in monitoring food safety. In addition, the overall economical feasibility will be assessed in a rough calculation of costs, and strengths and weaknesses of FISH are considered in comparison with traditional and well-established detection methods.

  20. Biological Control of Chickpea Collar Rot by Co-inoculation of Antagonistic Bacteria and Compatible Rhizobia.

    PubMed

    Hameeda, B; Harini, G; Rupela, O P; Kumar Rao, J V D K; Reddy, Gopal

    2010-10-01

    Two hundred and seven bacteria were isolated from composts and macrofauna and screened for plant growth promoting and antagonistic traits. Seven of the 207 isolates showed antagonistic activity against Sclerotium rolfsii in plate culture. Inhibition of S. rolfsii by the bacterial isolates ranged between 61 and 84%. Two of the seven isolates were Bacillus sp. and rest belonged to Pseudomonas sp. Two isolates, Pseudomonas sp. CDB 35 and Pseudomonas sp. BWB 21 was compatible with chickpea Rhizobium sp. IC 59 and IC 76 in plate culture conditions. Increase in plant biomass (dry weight) ranged between 18 and 30% on application of these bacteria by seed coating and seed priming methods. However, by seed-priming there was an increase in plant biomass by 5-7% compared to seed coating. Number of nodules and the nodule weight was similar by both seed coating and seed priming methods. Disease incidence was reduced up to 47% in treatments where captan (fungicide) or antagonistic Pseudomonas sp. CDB 35 was applied. Increase in shoot weight was 36% by seed coating with Rhizobium sp. IC 59 and Pseudomonas sp. CDB 35 when compared to captan application. Whereas by seed priming with IC 59 and CDB 35 increased shoot weight by 3 and 39% increase in nodulation was observed.

  1. Effects of root inoculation with bacteria on the growth, Cd uptake and bacterial communities associated with rape grown in Cd-contaminated soil.

    PubMed

    Chen, Zhao-jin; Sheng, Xia-fang; He, Lin-yan; Huang, Zhi; Zhang, Wen-hui

    2013-01-15

    Two metal-resistant and plant growth-promoting bacteria (Burkholderia sp. J62 and Pseudomonas thivervalensis Y-1-3-9) were evaluated for their impacts on plant growth promotion, Cd availability in soil, and Cd uptake in rape (Brassica napus) grown in different level (0, 50, and 100 mg kg(-1)) of Cd-contaminated soils. The impacts of the bacteria on the rape-associated bacterial community structures were also evaluated using denaturing gradient gel electrophoresis (DGGE) analysis of bacterial DNA extracted from the root interior and rhizosphere and bulk soil samples collected at day 60 after inoculation. Canonical correspondence analysis (CCA) was used to have a comparative analysis of DGGE profiles. Inoculation with live bacteria not only significantly increased root (ranging from 38% to 86%), stem (ranging from 27% to 65%) and leaf (ranging from 23% to 55%) dry weights and water-extractive Cd contents (ranging from 59% to 237%) in the rhizosphere soils of the rape but also significantly increased root (ranging from 10% to 61%), stem (ranging from 41% to 57%) and leaf (ranging from 46% to 68%) total Cd uptake of rape compared to the dead bacterial-inoculated controls. DGGE and sequence analyses showed that the bacteria could colonize the rhizosphere soils and root interiors of rape plants. DGGE-CCA also showed that root interior and rhizosphere and bulk soil community profiles from the live bacteria-inoculated rape were significantly different from those from the dead bacteria-inoculated rape respectively. These results suggested that the bacteria had the potential to promote the growth and Cd uptake of rape and to influence the development of the rape-associated bacterial community structures.

  2. Monitoring of antimicrobial resistance in pathogenic bacteria from livestock animals.

    PubMed

    Wallmann, Jürgen

    2006-06-01

    Facing the problem of development and spreading of bacterial resistance, preventive strategies are considered the most appropriate means to counteract. The establishment of corresponding management options relies on scientifically defensible efforts to obtain objective data on the prevalence of bacterial resistance in healthy and diseased livestock. Additionally, detailed statistics are needed on the overall amount of antimicrobial agents dispensed in Germany. The collection of valid data on the prevalence of resistance requires representative and cross-sectional studies. The German national antimicrobial resistance monitoring of the Federal Office of Consumer Protection and Food Safety (BVL) determines the current quantitative resistance level of life-stock pathogens, in order to permit the evaluation and surveillance of the distribution of resistances on a valid basis. Essential key features determining the design of these studies comprise (1) a statistically valid sampling program. This incorporates regional differences in animal population density, (2) the avoidance of "copy strains", (3) testing of no more than two bacterial strains belonging to one species per herd, (4) testing only if no antimicrobial therapy preceded sample collection, and (5) the use of standardized methods [e.g. microdilution broth method to determine the minimal inhibitory concentration (MIC)]. The analysis and interpretation of this data permits reliable identification and definition of epidemiological characteristics of resistance and its development in animal associated bacteria, such as geographically and time wise differentiated profiles on its prevalence, the emergence of unknown phenotypes of resistance and an assessment of the threat resistant bacteria from animals pose for humans. In applied antimicrobial therapy, the data can serve as a decision guidance in choosing the antimicrobial agent most adapted to the prevailing epidemiological situation. The susceptibility testing

  3. Isolation of antibiotic-resistant pathogenic and potentially pathogenic bacteria from carpets of mosques in Tripoli, Libya

    PubMed Central

    Rahouma, Amal; Elghamoudi, Abdunabi; Nashnoush, Halima; Belhaj, Khalifa; Tawil, Khaled; Sifaw Ghenghesh, Khalifa

    2010-01-01

    Objective Isolation of potentially pathogenic bacteria from carpets in hospitals has been reported earlier, but not from carpets in mosques. The aim of the present study is to determine the pathogenic and potentially pathogenic bacteria that may exist on the carpets of mosques in Tripoli, Libya. Methods Dust samples from carpets were collected from 57 mosques in Tripoli. Samples were examined for pathogenic bacteria using standard bacteriological procedures. Susceptibility of isolated bacteria to antimicrobial agents was determined by the disc-diffusion method. Results Of dust samples examined, Salmonella spp. was detected in two samples (3.5%, 1 in group B and 1 in group C1), Escherichia coli in 16 samples (28.1%), Aeromonas spp. in one sample (1.8%), and Staphylococcus aureus in 12 samples (21.1%). Multiple drug resistance was observed in >16.7% of E. coli and in 25% of S. aureus. Conclusion Contamination of carpets in mosques of Tripoli with antibiotic-resistant pathogenic and potentially pathogenic bacteria may pose a health risk to worshipers, particularly, the very young, the old and the immunecompromised. Worshipers are encouraged to use personal praying mats when praying in mosques. PMID:21483559

  4. Screening lactic acid bacteria with high yielding-acid capacity from pickled tea for their potential uses of inoculating to ferment tea products.

    PubMed

    Xiao, Ping; Huang, Youyi; Yang, Wenpeng; Zhang, Bowei; Quan, Xiaoxia

    2015-10-01

    For there were very short of excellent strains inoculated to ferment tea products, the lactic acid bacteria from pickled tea were isolated, characterized and identified, and the acid production capacity of part better strains was determined. There are only 22 strains isolated from pickled tea, and 2 of them were yeast, and 8 strains selected from the other 20 strains all were identified as Lactobacillus plantarum. A1, L2 and L5 of L. plantarum with a high acid production capacity were screened out and could obviously shorten the fermentation time of pickled tea by the verification, which suggests that they have a potential use of inoculating to ferment tea products. It was the first report on screening lactic acid bacteria with high yielding-acid capacity from pickled tea, which will bring benefits to fermenting tea products by artificial inoculation. PMID:26396422

  5. Targeting solid tumors with non-pathogenic obligate anaerobic bacteria.

    PubMed

    Taniguchi, Shun'ichiro; Fujimori, Minoru; Sasaki, Takayuki; Tsutsui, Hiroko; Shimatani, Yuko; Seki, Keiichi; Amano, Jun

    2010-09-01

    Molecular-targeting drugs with fewer severe adverse effects are attracting great attention as the next wave of cancer treatment. There exist, however, populations of cancer cells resistant to these drugs that stem from the instability of tumor cells and/or the existence of cancer stem cells, and thus specific toxicity is required to destroy them. If such selectivity is not available, these targets may be sought out not by the cancer cell types themselves, but rather in their adjacent cancer microenvironments by means of hypoxia, low pH, and so on. The anaerobic conditions present in malignant tumor tissues have previously been regarded as a source of resistance in cancer cells against conventional therapy. However, there now appears to be a way to make use of these limiting factors as a selective target. In this review, we will refer to several trials, including our own, to direct attention to the utilizable anaerobic conditions present in malignant tumor tissues and the use of bacteria as carriers to target them. Specifically, we have been developing a method to attack solid cancers using the non-pathogenic obligate anaerobic bacterium Bifidobacterium longum as a vehicle to selectively recognize and target the anaerobic conditions in solid cancer tissues. We will also discuss the existence of low oxygen pressure in tumor masses in spite of generally enhanced angiogenesis, overview current cancer therapies, especially the history and present situation of bacterial utility to treat solid tumors, and discuss the rationality and future possibilities of this novel mode of cancer treatment.

  6. Inhibition of citrus fungal pathogens by using lactic acid bacteria.

    PubMed

    Gerez, C L; Carbajo, M S; Rollán, G; Torres Leal, G; Font de Valdez, G

    2010-08-01

    The effect of lactic acid bacteria (LAB) on pathogenic fungi was evaluated and the metabolites involved in the antifungal effect were characterized. Penicillium digitatum (INTA 1 to INTA 7) and Geotrichum citri-aurantii (INTA 8) isolated from decayed lemon from commercial packinghouses were treated with imazalil and guazatine to obtain strains resistant to these fungicides. The most resistant strains (4 fungal strains) were selected for evaluating the antifungal activity of 33 LAB strains, among which only 8 strains gave positive results. The antifungal activity of these LAB strains was related to the production of lactic acid, acetic acid, and phenyllactic acid (PLA). A central composite design and the response surface methodology were used to evaluate the inhibitory effect of the organic acids produced by the LAB cultures. The antifungal activity of lactic acid was directly related to its concentration; however, acetic acid and PLA showed a peak of activity at 52.5 and 0.8 mM, respectively, with inhibition rates similar to those obtained with Serenade((R)) (3.0 ppm) imazalil (50 ppm) and guazatine (50 ppm). Beyond the peak of activity, a reduction in effectiveness of both acetic acid and PLA was observed. Comparing the inhibition rate of the organic acids, PLA was about 66- and 600-fold more effective than acetic acid and lactic acid, respectively. This study presents evidences on the antifungal effect of selected LAB strains and their end products. Studies are currently being undertaken to evaluate the effectiveness in preventing postharvest diseases on citrus fruits. PMID:20722936

  7. Impact on Arbuscular Mycorrhiza Formation of Pseudomonas Strains Used as Inoculants for Biocontrol of Soil-Borne Fungal Plant Pathogens

    PubMed Central

    Barea, J. M.; Andrade, G.; Bianciotto, V.; Dowling, D.; Lohrke, S.; Bonfante, P.; O’Gara, F.; Azcon-Aguilar, C.

    1998-01-01

    The arbuscular mycorrhizal symbiosis, a key component of agroecosystems, was assayed as a rhizosphere biosensor for evaluation of the impact of certain antifungal Pseudomonas inoculants used to control soil-borne plant pathogens. The following three Pseudomonas strains were tested: wild-type strain F113, which produces the antifungal compound 2,4-diacetylphloroglucinol (DAPG); strain F113G22, a DAPG-negative mutant of F113; and strain F113(pCU203), a DAPG overproducer. Wild-type strain F113 and mutant strain F113G22 stimulated both mycelial development from Glomus mosseae spores germinating in soil and tomato root colonization. Strain F113(pCU203) did not adversely affect G. mosseae performance. Mycelial development, but not spore germination, is sensitive to 10 μM DAPG, a concentration that might be present in the rhizosphere. The results of scanning electron and confocal microscopy demonstrated that strain F113 and its derivatives adhered to G. mosseae spores independent of the ability to produce DAPG. PMID:9603857

  8. Erythrophore cell response to food-associated pathogenic bacteria: implications for detection.

    PubMed

    Hutchison, Janine R; Dukovcic, Stephanie R; Dierksen, Karen P; Carlyle, Calvin A; Caldwell, Bruce A; Trempy, Janine E

    2008-09-01

    Cell-based biosensors have been proposed for use as function-based detectors of toxic agents. We report the use of Betta splendens chromatophore cells, specifically erythrophore cells, for detection of food-associated pathogenic bacteria. Evaluation of erythrophore cell response, using Bacillus spp., has revealed that this response can distinguish pathogenic Bacillus cereus from a non-pathogenic B. cereus ΔplcR deletion mutant and a non-pathogenic Bacillus subtilis. Erythrophore cells were exposed to Salmonella enteritidis, Clostridium perfringens and Clostridium botulinum. Each bacterial pathogen elicited a response from erythrophore cells that was distinguished from the corresponding bacterial growth medium, and this observed response was unique for each bacterial pathogen. These findings suggest that erythrophore cell response has potential for use as a biosensor in the detection and toxicity assessment for food-associated pathogenic bacteria. PMID:21261862

  9. Promotion of arsenic phytoextraction efficiency in the fern Pteris vittata by the inoculation of As-resistant bacteria: a soil bioremediation perspective.

    PubMed

    Lampis, Silvia; Santi, Chiara; Ciurli, Adriana; Andreolli, Marco; Vallini, Giovanni

    2015-01-01

    A greenhouse pot experiment was carried out to evaluate the efficiency of arsenic phytoextraction by the fern Pteris vittata growing in arsenic-contaminated soil, with or without the addition of selected rhizobacteria isolated from the polluted site. The bacterial strains were selected for arsenic resistance, the ability to reduce arsenate to arsenite, and the ability to promote plant growth. P. vittata plants were cultivated for 4 months in a contaminated substrate consisting of arsenopyrite cinders and mature compost. Four different experimental conditions were tested: (i) non-inoculated plants; (ii) plants inoculated with the siderophore-producing and arsenate-reducing bacteria Pseudomonas sp. P1III2 and Delftia sp. P2III5 (A); (iii) plants inoculated with the siderophore and indoleacetic acid-producing bacteria Bacillus sp. MPV12, Variovorax sp. P4III4, and Pseudoxanthomonas sp. P4V6 (B), and (iv) plants inoculated with all five bacterial strains (AB). The presence of growth-promoting rhizobacteria increased plant biomass by up to 45% and increased As removal efficiency from 13% without bacteria to 35% in the presence of the mixed inoculum. Molecular analysis confirmed the persistence of the introduced bacterial strains in the soil and resulted in a significant impact on the structure of the bacterial community. PMID:25741356

  10. Promotion of arsenic phytoextraction efficiency in the fern Pteris vittata by the inoculation of As-resistant bacteria: a soil bioremediation perspective

    PubMed Central

    Lampis, Silvia; Santi, Chiara; Ciurli, Adriana; Andreolli, Marco; Vallini, Giovanni

    2015-01-01

    A greenhouse pot experiment was carried out to evaluate the efficiency of arsenic phytoextraction by the fern Pteris vittata growing in arsenic-contaminated soil, with or without the addition of selected rhizobacteria isolated from the polluted site. The bacterial strains were selected for arsenic resistance, the ability to reduce arsenate to arsenite, and the ability to promote plant growth. P. vittata plants were cultivated for 4 months in a contaminated substrate consisting of arsenopyrite cinders and mature compost. Four different experimental conditions were tested: (i) non-inoculated plants; (ii) plants inoculated with the siderophore-producing and arsenate-reducing bacteria Pseudomonas sp. P1III2 and Delftia sp. P2III5 (A); (iii) plants inoculated with the siderophore and indoleacetic acid-producing bacteria Bacillus sp. MPV12, Variovorax sp. P4III4, and Pseudoxanthomonas sp. P4V6 (B), and (iv) plants inoculated with all five bacterial strains (AB). The presence of growth-promoting rhizobacteria increased plant biomass by up to 45% and increased As removal efficiency from 13% without bacteria to 35% in the presence of the mixed inoculum. Molecular analysis confirmed the persistence of the introduced bacterial strains in the soil and resulted in a significant impact on the structure of the bacterial community. PMID:25741356

  11. Effect of clove oil on plant pathogenic bacteria and bacterial wilt of tomato and geranium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We determined the antibacterial activity of clove oil against seven different genera of plant pathogenic bacteria including Gram-negative Agrobacterium tumefaciens, Erwinia carotovora pv. carotovora, Pseudomonas syringae pv. syringae, Ralstonia solanacearum, and Xanthomonas campestris pv. pelargonii...

  12. Effect of fermented broth from lactic acid bacteria on pathogenic bacteria proliferation.

    PubMed

    Gutiérrez, S; Martínez-Blanco, H; Rodríguez-Aparicio, L B; Ferrero, M A

    2016-04-01

    In this study, the effect that 5 fermented broths of lactic acid bacteria (LAB) strains have on the viability or proliferation and adhesion of 7 potentially pathogenic microorganisms was tested. The fermented broth from Lactococcus lactis C660 had a growth inhibitory effect on Escherichia coli K92 that reached of 31%, 19% to Pseudomonas fluorescens, and 76% to Staphylococcus epidermidis. The growth of Staph. epidermidis was negatively affected to 90% by Lc. lactis 11454 broth, whereas the growth of P. fluorescens (25%) and both species of Staphylococcus (35% to Staphylococcus aureus and 76% to Staph. epidermidis) were inhibited when they were incubated in the presence of Lactobacillus casei 393 broth. Finally, the fermented broth of Lactobacillus rhamnosus showed an inhibitory effect on growth of E. coli K92, Listeria innocua, and Staph. epidermidis reached values of 12, 28, and 76%, respectively. Staphylococcus epidermidis was the most affected strain because the effect was detected from the early stages of growth and it was completely abolished. The results of bacterial adhesion revealed that broths from Lc. lactis strains, Lactobacillus paracasei, and Lb. rhamnosus caused a loss of E. coli K92 adhesion. Bacillus cereus showed a decreased of adhesion in the presence of the broths of Lc. lactis strains and Lb. paracasei. Listeria innocua adhesion inhibition was observed in the presence of Lb. paracasei broth, and the greatest inhibitory effect was registered when this pathogenic bacterium was incubated in presence of Lc. lactis 11454 broth. With respect to the 2 Pseudomonas, we observed a slight adhesion inhibition showed by Lactobacillus rhamnosus broth against Pseudomonas putida. These results confirm that the effect caused by the different LAB assayed is also broth- and species-specific and reveal that the broth from LAB tested can be used as functional bioactive compounds to regulate the adhesion and biofilm synthesis and ultimately lead to preventing food and

  13. Effect of fermented broth from lactic acid bacteria on pathogenic bacteria proliferation.

    PubMed

    Gutiérrez, S; Martínez-Blanco, H; Rodríguez-Aparicio, L B; Ferrero, M A

    2016-04-01

    In this study, the effect that 5 fermented broths of lactic acid bacteria (LAB) strains have on the viability or proliferation and adhesion of 7 potentially pathogenic microorganisms was tested. The fermented broth from Lactococcus lactis C660 had a growth inhibitory effect on Escherichia coli K92 that reached of 31%, 19% to Pseudomonas fluorescens, and 76% to Staphylococcus epidermidis. The growth of Staph. epidermidis was negatively affected to 90% by Lc. lactis 11454 broth, whereas the growth of P. fluorescens (25%) and both species of Staphylococcus (35% to Staphylococcus aureus and 76% to Staph. epidermidis) were inhibited when they were incubated in the presence of Lactobacillus casei 393 broth. Finally, the fermented broth of Lactobacillus rhamnosus showed an inhibitory effect on growth of E. coli K92, Listeria innocua, and Staph. epidermidis reached values of 12, 28, and 76%, respectively. Staphylococcus epidermidis was the most affected strain because the effect was detected from the early stages of growth and it was completely abolished. The results of bacterial adhesion revealed that broths from Lc. lactis strains, Lactobacillus paracasei, and Lb. rhamnosus caused a loss of E. coli K92 adhesion. Bacillus cereus showed a decreased of adhesion in the presence of the broths of Lc. lactis strains and Lb. paracasei. Listeria innocua adhesion inhibition was observed in the presence of Lb. paracasei broth, and the greatest inhibitory effect was registered when this pathogenic bacterium was incubated in presence of Lc. lactis 11454 broth. With respect to the 2 Pseudomonas, we observed a slight adhesion inhibition showed by Lactobacillus rhamnosus broth against Pseudomonas putida. These results confirm that the effect caused by the different LAB assayed is also broth- and species-specific and reveal that the broth from LAB tested can be used as functional bioactive compounds to regulate the adhesion and biofilm synthesis and ultimately lead to preventing food and

  14. Pathogenic bacteria isolated from disease outbreaks in shellfish hatcheries. First description of Vibrio neptunius as an oyster pathogen.

    PubMed

    Prado, Susana; Romalde, Jesús L; Montes, Jaime; Barja, Juan L

    2005-11-28

    Shellfish hatcheries are often affected by disease outbreaks. Three such episodes were investigated in different Galician hatcheries in order to establish the relationship between present microbiota and mortalities. Isolates were obtained from various parts of the hatcheries. Experimental tests for pathogenicity were carried out in microscale experiments using selected strains on Ostrea edulis larvae. The pathogenicity of 1 strain from each outbreak was demonstrated and shown to cause high mortalities (ranging from 98.5 to 100%) in 72 to 96 h after inoculation of larval cultures. All 3 strains belong to the genus Vibrio. One of the strains was identified as Vibrio neptunius and is the first description of this species as a molluscan pathogen. The other 2 strains showed low similarity with the Vibrio species analysed and may constitute new species within this genus.

  15. Insights into Cross-Kingdom Plant Pathogenic Bacteria

    PubMed Central

    Kirzinger, Morgan W.B.; Nadarasah, Geetanchaly; Stavrinides, John

    2011-01-01

    Plant and human pathogens have evolved disease factors to successfully exploit their respective hosts. Phytopathogens utilize specific determinants that help to breach reinforced cell walls and manipulate plant physiology to facilitate the disease process, while human pathogens use determinants for exploiting mammalian physiology and overcoming highly developed adaptive immune responses. Emerging research, however, has highlighted the ability of seemingly dedicated human pathogens to cause plant disease, and specialized plant pathogens to cause human disease. Such microbes represent interesting systems for studying the evolution of cross-kingdom pathogenicity, and the benefits and tradeoffs of exploiting multiple hosts with drastically different morphologies and physiologies. This review will explore cross-kingdom pathogenicity, where plants and humans are common hosts. We illustrate that while cross-kingdom pathogenicity appears to be maintained, the directionality of host association (plant to human, or human to plant) is difficult to determine. Cross-kingdom human pathogens, and their potential plant reservoirs, have important implications for the emergence of infectious diseases. PMID:24710301

  16. Enhancement of microbial quality and inactivation of pathogenic bacteria by gamma irradiation of ready-to-cook Iranian barbecued chicken

    NASA Astrophysics Data System (ADS)

    Fallah, Aziz A.; Siavash Saei-Dehkordi, S.; Rahnama, Mohammad

    2010-10-01

    Ready-to-cook Iranian barbecued chicken consists of cubed chicken breast, lemon juice, salt, red pepper, onion, saffron and vegetable oil with an overall pH value of about 5.5. This product is sometimes consumed under-cooked, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. In this study, the effect of gamma irradiation (0, 1.5, 3 and 4.5 kGy) on the microbial quality of ready-to-cook (RTC) barbecued chicken samples stored at 4 °C for 15 days was investigated. Moreover, the effectiveness of irradiation for inactivating Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella typhimurium inoculated into the samples was also studied. Irradiation of the samples resulted in dose dependent reduction in counts of aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and lactic acid bacteria. Among the microbial flora, yeasts and molds and Enterobacteriaceae were more sensitive to irradiation and got completely eliminated at dose of 3 kGy. D10 values of L. monocytogenes, E. coli O157:H7 and S. typhimurium inoculated into the samples were 0.680, 0.397 and 0.601 kGy, respectively. An irradiation dose of 3 kGy reduced the counts of E. coli O157:H7 to an undetectable level in RTC barbecued chicken but was ineffective on elimination of L. monocytogenes and S. typhimurium. However, none of the food-borne pathogens were detected in the samples irradiated at 4.5 kGy. This study showed that irradiation had no undesirable effects on the initial sensory attributes of barbecued chicken. At the end of the storage period, irradiated samples were more acceptable compared to non-irradiated ones.

  17. Comparison of different inoculating methods to evaluate the pathogenicity and virulence of Aspergillus niger on two maize hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-year field study was conducted to determine the effects of inoculation techniques on the aggressiveness of Aspergillus niger kernel infection in A. flavus resistant and susceptible maize hybrids. Ears were inoculated with the silk-channel, side-needle, and spray techniques 7 days after midsilk...

  18. Pathogenesis in Eurasian tree sparrows inoculated with H5N1 highly pathogenic avian influenza virus and experimental virus transmission from tree sparrows to chickens.

    PubMed

    Yamamoto, Yu; Nakamura, Kikuyasu; Yamada, Manabu; Mase, Masaji

    2013-06-01

    Small wild birds that routinely enter poultry farms may be possible vectors of Asian lineage H5N1 highly pathogenic avian influenza virus. In this study, we conducted experimental infections using wild-caught Eurasian tree sparrows (Passer montanus) to evaluate their possible epidemiological involvement in virus transmission. When tree sparrows were intranasally inoculated with the virus at a low or high dose, all sparrows excluding euthanatized birds died within 11 days after inoculation. Viruses were frequently isolated from the drinking water, oral swabs, and visceral organs of the sparrows. Immunohistochemical analysis revealed that the virus replicated strongly in the central nervous system, heart, and adrenal gland following primary infection in the upper respiratory tract and a probable subsequent viremic stage. In the contact infection study using virus-inoculated sparrows and untreated contact chickens, more than half of all chickens died from viral infection. In the virus transmission study in which chickens were given drinking water collected from virus-inoculated sparrows, mortality due to viral infection was observed in chickens. Our data suggest that Eurasian tree sparrows could be biological vectors of the H5N1 highly pathogenic avian influenza virus. In addition to frequent virus detection in the drinking water of sparrows, the results of the virus transmission study suggest that waterborne pathways could be important for viral transmission from tree sparrows to poultry.

  19. Megacities as Sources for Pathogenic Bacteria in Rivers and Their Fate Downstream

    PubMed Central

    Abraham, Wolf-Rainer

    2011-01-01

    Poor sanitation, poor treatments of waste water, as well as catastrophic floods introduce pathogenic bacteria into rivers, infecting and killing many people. The goal of clean water for everyone has to be achieved with a still growing human population and their rapid concentration in large cities, often megacities. How long introduced pathogens survive in rivers and what their niches are remain poorly known but essential to control water-borne diseases in megacities. Biofilms are often niches for various pathogens because they possess high resistances against environmental stress. They also facilitate gene transfers of antibiotic resistance genes which become an increasing health problem. Beside biofilms, amoebae are carriers of pathogenic bacteria and niches for their survival. An overview about our current understanding of the fate and niches of pathogens in rivers, the multitude of microbial community interactions, and the impact of severe flooding, a prerequisite to control pathogens in polluted rivers, is given. PMID:20885968

  20. Antibacterial activity of plant extracts on foodborne bacterial pathogens and food spoilage bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...

  1. A mathematical model for expected time to extinction of pathogenic bacteria through antibiotic

    NASA Astrophysics Data System (ADS)

    Ghosh, M. K.; Nandi, S.; Roy, P. K.

    2016-04-01

    Application of antibiotics in human system to prevent bacterial diseases like Gastritis, Ulcers, Meningitis, Pneumonia and Gonorrhea are indispensable. Antibiotics saved innumerable lives and continue to be a strong support for therapeutic application against pathogenic bacteria. In human system, bacterial diseases occur when pathogenic bacteria gets into the body and begin to reproduce and crowd out healthy bacteria. In this process, immature bacteria releases enzyme which is essential for bacterial cell-wall biosynthesis. After complete formation of cell wall, immature bacteria are converted to mature or virulent bacteria which are harmful to us during bacterial infections. Use of antibiotics as drug inhibits the bacterial cell wall formation. After application of antibiotics within body, the released bacterial enzyme binds with antibiotic molecule instead of its functional site during the cell wall synthesis in a competitive inhibition approach. As a consequence, the bacterial cell-wall formation as well as maturation process of pathogenic bacteria is halted and the disease is cured with lysis of bacterial cells. With this idea, a mathematical model has been developed in the present research investigation to review the inhibition of biosynthesis of bacterial cell wall by the application of antibiotics as drug in the light of enzyme kinetics. This approach helps to estimate the expected time to extinction of the pathogenic bacteria. Our mathematical approach based on the enzyme kinetic model for finding out expected time to extinction contributes favorable results for understanding of disease dynamics. Analytical and numerical results based on simulated findings validate our mathematical model.

  2. Essential oils have different effects on human pathogenic and commensal bacteria in mixed faecal fermentations compared with pure cultures.

    PubMed

    Thapa, Dinesh; Louis, Petra; Losa, Riccardo; Zweifel, Béatrice; Wallace, R John

    2015-02-01

    A static batch culture system inoculated with human faeces was used to determine the influence of essential oil compounds (EOCs) on mixed faecal microbiota. Bacteria were quantified using quantitative PCR of 16S rRNA genes. Incubation for 24 h of diluted faeces from six individuals caused enrichment of Bifidobacterium spp., but proportions of other major groups were unaffected. Thymol and geraniol at 500 p.p.m. suppressed total bacteria, resulting in minimal fermentation. Thymol at 100 p.p.m. had no effect, nor did eugenol or nerolidol at 100 or 500 p.p.m. except for a slight suppression of Eubacterium hallii. Methyl isoeugenol at 100 or 500 p.p.m. suppressed the growth of total bacteria, accompanied by a large fall in the molar proportion of propionate formed. The relative abundance of Faecalibacterium prausnitzii was unaffected except with thymol at 500 p.p.m. The ability of EOCs to control numbers of the pathogen Clostridium difficile was investigated in a separate experiment, in which the faecal suspensions were amended by the addition of pure culture of C. difficile. Numbers of C. difficile were suppressed by thymol and methyl isoeugenol at 500 p.p.m. and to a lesser extent at 100 p.p.m. Eugenol and geraniol gave rather similar suppression of C. difficile numbers at both 100 and 500 p.p.m. Nerolidol had no significant effect. It was concluded from these and previous pure-culture experiments that thymol and geraniol at around 100 p.p.m. could be effective in suppressing pathogens in the small intestine, with no concern for beneficial commensal colonic bacteria in the distal gut. PMID:25500493

  3. Essential oils have different effects on human pathogenic and commensal bacteria in mixed faecal fermentations compared with pure cultures.

    PubMed

    Thapa, Dinesh; Louis, Petra; Losa, Riccardo; Zweifel, Béatrice; Wallace, R John

    2015-02-01

    A static batch culture system inoculated with human faeces was used to determine the influence of essential oil compounds (EOCs) on mixed faecal microbiota. Bacteria were quantified using quantitative PCR of 16S rRNA genes. Incubation for 24 h of diluted faeces from six individuals caused enrichment of Bifidobacterium spp., but proportions of other major groups were unaffected. Thymol and geraniol at 500 p.p.m. suppressed total bacteria, resulting in minimal fermentation. Thymol at 100 p.p.m. had no effect, nor did eugenol or nerolidol at 100 or 500 p.p.m. except for a slight suppression of Eubacterium hallii. Methyl isoeugenol at 100 or 500 p.p.m. suppressed the growth of total bacteria, accompanied by a large fall in the molar proportion of propionate formed. The relative abundance of Faecalibacterium prausnitzii was unaffected except with thymol at 500 p.p.m. The ability of EOCs to control numbers of the pathogen Clostridium difficile was investigated in a separate experiment, in which the faecal suspensions were amended by the addition of pure culture of C. difficile. Numbers of C. difficile were suppressed by thymol and methyl isoeugenol at 500 p.p.m. and to a lesser extent at 100 p.p.m. Eugenol and geraniol gave rather similar suppression of C. difficile numbers at both 100 and 500 p.p.m. Nerolidol had no significant effect. It was concluded from these and previous pure-culture experiments that thymol and geraniol at around 100 p.p.m. could be effective in suppressing pathogens in the small intestine, with no concern for beneficial commensal colonic bacteria in the distal gut.

  4. Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales

    PubMed Central

    2010-01-01

    Background Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis. Results Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes. Conclusions The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle evolution in these

  5. Molecular Analysis of Pathogenic Bacteria and Their Toxins

    NASA Astrophysics Data System (ADS)

    Logue, Catherine M.; Nolan, Lisa K.

    Use of molecular methods for investigation of foodborne pathogens and illness has become much more commonplace over the last decade or so. Application of these methods has significantly expanded fields of inquiry related to food safety. Molecular methods have been used to facilitate isolation and detection of pathogens and to enhance subtype analysis of strains in an effort to link or determine relationships between strains and hosts and to sources of contamination.

  6. Comparison of antibodies raised against heat-and gamma radiation-killed bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For antibody generation, pathogenic bacteria are often heat-treated prior to inoculation into host animals in order to prevent infection and subsequently, premature death of the host. Inoculation of host rabbits with gamma radiation-killed pathogenic bacteria was employed with the hopes of generati...

  7. A Reservoir of Drug-Resistant Pathogenic Bacteria in Asymptomatic Hosts

    PubMed Central

    Perron, Gabriel G.; Quessy, Sylvain; Bell, Graham

    2008-01-01

    The population genetics of pathogenic bacteria has been intensively studied in order to understand the spread of disease and the evolution of virulence and drug resistance. However, much less attention has been paid to bacterial carriage populations, which inhabit hosts without producing disease. Since new virulent strains that cause disease can be recruited from the carriage population of bacteria, our understanding of infectious disease is seriously incomplete without knowledge on the population structure of pathogenic bacteria living in an asymptomatic host. We report the first extensive survey of the abundance and diversity of a human pathogen in asymptomatic animal hosts. We have found that asymptomatic swine from livestock productions frequently carry populations of Salmonella enterica with a broad range of drug-resistant strains and genetic diversity greatly exceeding that previously described. This study shows how agricultural practice and human intervention may lead and influence the evolution of a hidden reservoir of pathogens, with important implications for human health. PMID:19015729

  8. Bacteria between protists and phages: from antipredation strategies to the evolution of pathogenicity.

    PubMed

    Brüssow, Harald

    2007-08-01

    Bacteriophages and protists are major causes of bacterial mortality. Genomics suggests that phages evolved well before eukaryotic protists. Bacteria were thus initially only confronted with phage predators. When protists evolved, bacteria were caught between two types of predators. One successful antigrazing strategy of bacteria was the elaboration of toxins that would kill the grazer. The released cell content would feed bystander bacteria. I suggest here that, to fight grazing protists, bacteria teamed up with those phage predators that concluded at least a temporary truce with them in the form of lysogeny. Lysogeny was perhaps initially a resource management strategy of phages that could not maintain infection chains. Subsequently, lysogeny might have evolved into a bacterium-prophage coalition attacking protists, which became a food source for them. When protists evolved into multicellular animals, the lysogenic bacteria tracked their evolving food source. This hypothesis could explain why a frequent scheme of bacterial pathogenicity is the survival in phagocytes, why a significant fraction of bacterial pathogens have prophage-encoded virulence genes, and why some virulence factors of animal pathogens are active against unicellular eukaryotes. Bacterial pathogenicity might thus be one playing option of the stone-scissor-paper game played between phages-bacteria-protists, with humans getting into the crossfire.

  9. A Complex Inoculant of N2-Fixing, P- and K-Solubilizing Bacteria from a Purple Soil Improves the Growth of Kiwifruit (Actinidia chinensis) Plantlets

    PubMed Central

    Shen, Hong; He, Xinhua; Liu, Yiqing; Chen, Yi; Tang, Jianming; Guo, Tao

    2016-01-01

    Limited information is available if plant growth promoting bacteria (PGPB) can promote the growth of fruit crops through improvements in soil fertility. This study aimed to evaluate the capacity of PGPB, identified by phenotypic and 16S rRNA sequencing from a vegetable purple soil in Chongqing, China, to increase soil nitrogen (N), phosphorus (P), and potassium (K) availability and growth of kiwifruit (Actinidia chinensis). In doing so, three out of 17 bacterial isolates with a high capacity of N2-fixation (Bacillus amyloliquefaciens, XD-N-3), P-solubilization (B. pumilus, XD-P-1) or K-solubilization (B. circulans, XD-K-2) were mixed as a complex bacterial inoculant. A pot experiment then examined its effects of this complex inoculant on soil microflora, soil N2-fixation, P- and K-solubility and kiwifruit growth under four treatments. These treatments were (1) no-fertilizer and no-bacterial inoculant (Control), (2) no-bacterial inoculant and a full-rate of chemical NPK fertilizer (CF), (3) the complex inoculant (CI), and (4) a half-rate CF and full CI (1/2CF+CI). Results indicated that significantly greater growth of N2-fixing, P- and K-solubilizing bacteria among treatments ranked from greatest to least as under 1/2CF+CI ≈ CI > CF ≈ Control. Though generally without significant treatment differences in soil total N, P, or K, significantly greater soil available N, P, or K among treatments was, respectively, patterned as under 1/2CF+CI ≈ CI > CF ≈ Control, under 1/2CF+CI > CF > CI > Control or under 1/2CF+CI > CF ≈ CI > Control, indicating an improvement of soil fertility by this complex inoculant. In regards to plant growth, significantly greater total plant biomass and total N, P, and K accumulation among treatments were ranked as 1/2CF+CI ≈ CI > CF > Control. Additionally, significantly greater leaf polyphenol oxidase activity ranked as under CF > 1/2CF+CI ≈ Control ≈ CI, while leaf malondialdehyde contents as under Control > CI ≈ CF > 1/2CF

  10. A Complex Inoculant of N2-Fixing, P- and K-Solubilizing Bacteria from a Purple Soil Improves the Growth of Kiwifruit (Actinidia chinensis) Plantlets.

    PubMed

    Shen, Hong; He, Xinhua; Liu, Yiqing; Chen, Yi; Tang, Jianming; Guo, Tao

    2016-01-01

    Limited information is available if plant growth promoting bacteria (PGPB) can promote the growth of fruit crops through improvements in soil fertility. This study aimed to evaluate the capacity of PGPB, identified by phenotypic and 16S rRNA sequencing from a vegetable purple soil in Chongqing, China, to increase soil nitrogen (N), phosphorus (P), and potassium (K) availability and growth of kiwifruit (Actinidia chinensis). In doing so, three out of 17 bacterial isolates with a high capacity of N2-fixation (Bacillus amyloliquefaciens, XD-N-3), P-solubilization (B. pumilus, XD-P-1) or K-solubilization (B. circulans, XD-K-2) were mixed as a complex bacterial inoculant. A pot experiment then examined its effects of this complex inoculant on soil microflora, soil N2-fixation, P- and K-solubility and kiwifruit growth under four treatments. These treatments were (1) no-fertilizer and no-bacterial inoculant (Control), (2) no-bacterial inoculant and a full-rate of chemical NPK fertilizer (CF), (3) the complex inoculant (CI), and (4) a half-rate CF and full CI (1/2CF+CI). Results indicated that significantly greater growth of N2-fixing, P- and K-solubilizing bacteria among treatments ranked from greatest to least as under 1/2CF+CI ≈ CI > CF ≈ Control. Though generally without significant treatment differences in soil total N, P, or K, significantly greater soil available N, P, or K among treatments was, respectively, patterned as under 1/2CF+CI ≈ CI > CF ≈ Control, under 1/2CF+CI > CF > CI > Control or under 1/2CF+CI > CF ≈ CI > Control, indicating an improvement of soil fertility by this complex inoculant. In regards to plant growth, significantly greater total plant biomass and total N, P, and K accumulation among treatments were ranked as 1/2CF+CI ≈ CI > CF > Control. Additionally, significantly greater leaf polyphenol oxidase activity ranked as under CF > 1/2CF+CI ≈ Control ≈ CI, while leaf malondialdehyde contents as under Control > CI ≈ CF > 1/2CF

  11. A Complex Inoculant of N2-Fixing, P- and K-Solubilizing Bacteria from a Purple Soil Improves the Growth of Kiwifruit (Actinidia chinensis) Plantlets.

    PubMed

    Shen, Hong; He, Xinhua; Liu, Yiqing; Chen, Yi; Tang, Jianming; Guo, Tao

    2016-01-01

    Limited information is available if plant growth promoting bacteria (PGPB) can promote the growth of fruit crops through improvements in soil fertility. This study aimed to evaluate the capacity of PGPB, identified by phenotypic and 16S rRNA sequencing from a vegetable purple soil in Chongqing, China, to increase soil nitrogen (N), phosphorus (P), and potassium (K) availability and growth of kiwifruit (Actinidia chinensis). In doing so, three out of 17 bacterial isolates with a high capacity of N2-fixation (Bacillus amyloliquefaciens, XD-N-3), P-solubilization (B. pumilus, XD-P-1) or K-solubilization (B. circulans, XD-K-2) were mixed as a complex bacterial inoculant. A pot experiment then examined its effects of this complex inoculant on soil microflora, soil N2-fixation, P- and K-solubility and kiwifruit growth under four treatments. These treatments were (1) no-fertilizer and no-bacterial inoculant (Control), (2) no-bacterial inoculant and a full-rate of chemical NPK fertilizer (CF), (3) the complex inoculant (CI), and (4) a half-rate CF and full CI (1/2CF+CI). Results indicated that significantly greater growth of N2-fixing, P- and K-solubilizing bacteria among treatments ranked from greatest to least as under 1/2CF+CI ≈ CI > CF ≈ Control. Though generally without significant treatment differences in soil total N, P, or K, significantly greater soil available N, P, or K among treatments was, respectively, patterned as under 1/2CF+CI ≈ CI > CF ≈ Control, under 1/2CF+CI > CF > CI > Control or under 1/2CF+CI > CF ≈ CI > Control, indicating an improvement of soil fertility by this complex inoculant. In regards to plant growth, significantly greater total plant biomass and total N, P, and K accumulation among treatments were ranked as 1/2CF+CI ≈ CI > CF > Control. Additionally, significantly greater leaf polyphenol oxidase activity ranked as under CF > 1/2CF+CI ≈ Control ≈ CI, while leaf malondialdehyde contents as under Control > CI ≈ CF > 1/2CF

  12. Effect of inoculation on strawberry fermentation and acetification processes using native strains of yeast and acetic acid bacteria.

    PubMed

    Hidalgo, C; Torija, M J; Mas, A; Mateo, E

    2013-05-01

    The aim of this work was to analyze the microbiota involved in the traditional vinegar elaboration of strawberry fruit during a spontaneous and inoculated process. In the spontaneous processes, low biodiversity was detected in both alcoholic fermentation (AF) and acetification. Nevertheless, a strain of Saccharomyces cerevisiae and of Acetobacter malorum were selected and tested as starter cultures in the inoculation study. The inoculated processes with these strains were compared with another spontaneous process, yielding a significant reduction in time for AF with a total imposition of the S. cerevisiae strain. The resulting strawberry wine was acetified in different containers (glass and wood) yielding an initial imposition of the A. malorum inoculated strain, although displacement by Gluconacetobacter species was observed in the wood barrels. PMID:23498182

  13. Modulation of host microtubule dynamics by pathogenic bacteria

    PubMed Central

    Radhakrishnan, Girish K.; Splitter, Gary A.

    2013-01-01

    The eukaryotic cytoskeleton is a vulnerable target of many microbial pathogens during the course of infection. Rearrangements of host cytoskeleton benefit microbes in various stages of their infection cycle such as invasion, motility, and persistence. Bacterial pathogens deliver a number of effector proteins into host cells for modulating the dynamics of actin and microtubule cytoskeleton. Alteration of the actin cytoskeleton is generally achieved by bacterial effectors that target the small GTPases of the host. Modulation of microtubule dynamics involves direct interaction of effector proteins with the subunits of microtubules or recruiting cellular proteins that affect microtubule dynamics. This review will discuss effector proteins from animal and human bacterial pathogens that either destabilize or stabilize host micro-tubules to advance the infectious process. A compilation of these research findings will provide an overview of known and unknown strategies used by various bacterial effectors to modulate the host microtubule dynamics. The present review will undoubtedly help direct future research to determine the mechanisms of action of many bacterial effector proteins and contribute to understanding the survival strategies of diverse adherent and invasive bacterial pathogens. PMID:23585820

  14. Association of plasma 25-hydroxyvitamin D concentrations and pathogenic oral bacteria in postmenopausal women

    PubMed Central

    Sahli, Michelle W; Wactawski-Wende, Jean; Ram, Pavani K; LaMonte, Michael J.; Hovey, Kathleen M.; Genco, Robert J.; Andrews, Christopher A.; Millen, Amy E.

    2014-01-01

    Background Previous findings of an association between 25-hydroxyvitamin D (25(OH)D) concentrations and periodontal disease, may be partially explained by vitamin D’s antimicrobial properties. To our knowledge, no study has investigated the association between 25(OH)D and pathogenic oral bacteria, a putative cause of periodontal disease. Methods We examined the association between plasma 25(OH)D concentrations and pathogenic oral bacteria among postmenopausal women in the Buffalo Osteoporosis and Periodontal Disease Study (1997–2000), an ancillary study of the Women’s Health Initiative Observational Study. Subgingival plaque samples were assessed using immunofluorescence for the presence of Porphyromonas gingivalis, Tannerella forsythensis, Fusobacterium nucleatum, Prevotella intermedia and Campylobacter rectus. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for prevalent bacteria by quintile (Q) of 25(OH)D concentrations adjusting for age and body mass index. Results Of the 855 participants, 288 (34%) had deficient/inadequate (<50 nmol/L) 25(OH)D concentrations and 497 (58%) had at least one species of pathogenic bacteria. No significant association was found between 25(OH)D and presence of any of these bacteria (adjusted OR for high (Q5) compared to low (Q1) 25(OH)D=0.96; 95% CI: 0.61–1.50, p for trend=0.50). Inverse, although not statistically significant, associations were found between 25(OH)D and more than one species of pathogenic bacteria (adjusted OR for adequate compared to deficient/inadequate 25(OH)D=0.85; 95% CI: 0.60–1.19). Conclusions No association was observed between pathogenic oral bacteria and 25(OH)D concentrations in postmenopausal women. This may be due to the species of bacteria assessed, small effect size or a true absence of an association. PMID:24261910

  15. quenched-smFISH: Counting small RNA in Pathogenic Bacteria

    NASA Astrophysics Data System (ADS)

    Shepherd, Douglas; Li, Nan; Micheva-Viteva, Sofiya; Munsky, Brian; Hong-Geller, Elizabeth; Werner, James

    2014-03-01

    Here, we present a modification to single-molecule fluorescence in situ hybridization, quenched smFISH (q-smFISH), that enables quantitative detection and analysis of small RNA (sRNA) expressed in bacteria. We show that short nucleic acid targets can be detected when the background of unbound singly dye-labeled DNA oligomers is reduced through hybridization with a set of complementary DNA oligomers labeled with a fluorescence quencher. Exploiting an automated, multi-color wide-field microscope and GPU-accelerated data analysis package, we analyzed the statistics of sRNA expression in thousands of individual Yersinia pseudotuberculosis and Yersinia pestis bacteria before and during a simulated infection. Before infection, we find only a small fraction of either bacteria express the small RNAs YSR35 or YSP8. The copy numbers of these RNA are increased during simulated infection, suggesting a role in pathogenesis. The ability to directly quantify expression level changes of sRNA in single cells as a function of external stimuli provides key information on the role of sRNA in bacterial regulatory networks.

  16. Inoculation experimental animals with Paracoccidioides brasiliensis strains: an attempt to reestablish the dimorphic process and variation in pathogenicity as a function of time of preservation under mineral oil.

    PubMed

    Mendes da Silva, A M; Borba, C M; de Oliveira, P C

    1996-01-01

    In an attempt to reestablish the dimorphic process in strains of Paracoccidioides brasiliensis in the transition phase (Y reversible M) and to reisolate them, five strains in the transitional phase due to the long time of preservation under mineral oil and two strains in the yeast-like phase were inoculated into male albino rats. The animals were then studied for the presence of paracoccidioidomycotic granulomata. Of the seven strains inoculated, five caused granulomatous nodules in several organs of the animals and only two of these five strains, which had been preserved for the shortest period of time (9 years) were reisolated in culture. Two strains were unable to provoke infection, with no lesions detected in any organ. It is assumed that the long period of time during which the strains were left under oil favored the alteration of celt wall contents, leading to differences in pathogenicity.

  17. Inoculating Helianthus annuus (sunflower) grown in zinc and cadmium contaminated soils with plant growth promoting bacteria--effects on phytoremediation strategies.

    PubMed

    Marques, Ana P G C; Moreira, Helena; Franco, Albina R; Rangel, António O S S; Castro, Paula M L

    2013-06-01

    Plant growth promoting bacteria (PGPR) may help reducing the toxicity of heavy metals to plants in polluted environments. In this work the effects of inoculating metal resistant and plant growth promoting bacterial strains on the growth of Helianthus annuus grown in Zn and Cd spiked soils were assessed. The PGPR strains Ralstonia eutropha (B1) and Chrysiobacterium humi (B2) reduced losses of weight in metal exposed plants and induced changes in metal bioaccumulation and bioconcentration - with strain B2 decreasing up to 67% Zn accumulation and by 20% Zn bioconcentration factor (BCF) in the shoots, up to 64% Zn uptake and 38% Zn BCF in the roots, and up to 27% Cd uptake and 27% Cd BCF in plant roots. The impact of inoculation on the bacterial communities in the rhizosphere of the plant was also assessed. Bacterial community diversity decreased with increasing levels of metal contamination in the soil, but in rhizosphere soil of plants inoculated with the PGPR strains, a higher bacterial diversity was kept throughout the experimental period. Inoculation of sunflower, particularly with C. humi (B2), appears to be an effective way of enhancing the short term stabilization potential of the plant in metal contaminated land, lowering losses in plant biomass and decreasing aboveground tissue contamination.

  18. The dynamic influence of commensal bacteria on the immune response to pathogens

    PubMed Central

    Abt, Michael C.; Artis, David

    2013-01-01

    Alterations in the composition of commensal bacterial communities are associated with enhanced susceptibility to multiple inflammatory, allergic, metabolic and infectious diseases in humans. In the context of infection, commensal bacteria-derived signals can influence the host immune response to invasive pathogens by acting as an adjuvant to boost the immune response to infection or by providing tonic stimulation to induce basal expression of factors required for host defense. Conversely, some pathogens have evolved mechanisms that can utilize commensal bacteria to establish a replicative advantage within the host. Thus, examining the dynamic relationship that exists between the mammalian host, commensal bacteria and invasive pathogens can provide insights into the etiology of pathogenesis from an infection. PMID:23332724

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

    PubMed

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

    2014-06-15

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

  20. The cytokine IL-22 promotes pathogen colonization by suppressing related commensal bacteria

    PubMed Central

    Behnsen, Judith; Jellbauer, Stefan; Wong, Christina P.; Edwards, Robert A.; George, Michael D.; Ouyang, Wenjun; Raffatellu, Manuela

    2014-01-01

    Summary Interleukin-22 (IL-22) is highly induced in response to infections with a variety of pathogens and its main functions are considered to be tissue repair and host defense at mucosal surfaces. Here we show that IL-22 has a previously undiscovered role during infection in that its expression suppresses the intestinal microbiota and enhances the colonization of a pathogen. IL-22 induced the expression of antimicrobial proteins, including lipocalin-2 and calprotectin, which sequester metal ions from microbes. As Salmonella Typhimurium overcomes metal starvation by lipocalin-2 and calprotectin, IL-22 boosted this pathogen’s colonization of the inflamed intestine by suppressing commensal Enterobacteriaceae, which in the absence of IL-22 overgrew S. Typhimurium. Thus, IL-22 expression can tip the balance between pathogenic and commensal bacteria in favor of a pathogen. Taken together, IL-22 induction can be exploited by pathogens to suppress the growth of their closest competitors, thereby enhancing pathogen colonization of mucosal surfaces. PMID:24508234

  1. 'Add, stir and reduce': Yersinia spp. as model bacteria for pathogen evolution.

    PubMed

    McNally, Alan; Thomson, Nicholas R; Reuter, Sandra; Wren, Brendan W

    2016-03-01

    Pathogenic species in the Yersinia genus have historically been targets for research aimed at understanding how bacteria evolve into mammalian pathogens. The advent of large-scale population genomic studies has greatly accelerated the progress in this field, and Yersinia pestis, Yersinia pseudotuberculosis and Yersinia enterocolitica have once again acted as model organisms to help shape our understanding of the evolutionary processes involved in pathogenesis. In this Review, we highlight the gene gain, gene loss and genome rearrangement events that have been identified by genomic studies in pathogenic Yersinia species, and we discuss how these findings are changing our understanding of pathogen evolution. Finally, as these traits are also found in the genomes of other species in the Enterobacteriaceae, we suggest that they provide a blueprint for the evolution of enteropathogenic bacteria.

  2. 'Add, stir and reduce': Yersinia spp. as model bacteria for pathogen evolution.

    PubMed

    McNally, Alan; Thomson, Nicholas R; Reuter, Sandra; Wren, Brendan W

    2016-03-01

    Pathogenic species in the Yersinia genus have historically been targets for research aimed at understanding how bacteria evolve into mammalian pathogens. The advent of large-scale population genomic studies has greatly accelerated the progress in this field, and Yersinia pestis, Yersinia pseudotuberculosis and Yersinia enterocolitica have once again acted as model organisms to help shape our understanding of the evolutionary processes involved in pathogenesis. In this Review, we highlight the gene gain, gene loss and genome rearrangement events that have been identified by genomic studies in pathogenic Yersinia species, and we discuss how these findings are changing our understanding of pathogen evolution. Finally, as these traits are also found in the genomes of other species in the Enterobacteriaceae, we suggest that they provide a blueprint for the evolution of enteropathogenic bacteria. PMID:26876035

  3. Comparison of fecal indicators with pathogenic bacteria and rotavirus in groundwater.

    PubMed

    Ferguson, Andrew S; Layton, Alice C; Mailloux, Brian J; Culligan, Patricia J; Williams, Daniel E; Smartt, Abby E; Sayler, Gary S; Feighery, John; McKay, Larry D; Knappett, Peter S K; Alexandrova, Ekaterina; Arbit, Talia; Emch, Michael; Escamilla, Veronica; Ahmed, Kazi Matin; Alam, Md Jahangir; Streatfield, P Kim; Yunus, Mohammad; van Geen, Alexander

    2012-08-01

    Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary.

  4. Occurrence of airborne bacteria and pathogen indicators during land application of sewage sludge.

    PubMed Central

    Pillai, S D; Widmer, K W; Dowd, S E; Ricke, S C

    1996-01-01

    Glass impingers (AGI-30) were used at a commercial sludge application site to determine the levels of airborne bacteria and pathogen indicators. Even though heterotrophic bacteria averaged 10(5) CFU/m3, none of the sites showed the presence of Salmonella spp. or indicators such as fecal coliforms or coliphages. Indicators such as H2S producers and pathogenic clostridia were present in locations having significant physical agitation of the sludge material. PCR-based ribotyping using the 16S-23S interspacer region is a promising method to identify the genetic relatedness and origins of airborne clostridia. PMID:8572708

  5. Plant pathogenic anaerobic bacteria use aromatic polyketides to access aerobic territory.

    PubMed

    Shabuer, Gulimila; Ishida, Keishi; Pidot, Sacha J; Roth, Martin; Dahse, Hans-Martin; Hertweck, Christian

    2015-11-01

    Around 25% of vegetable food is lost worldwide because of infectious plant diseases, including microbe-induced decay of harvested crops. In wet seasons and under humid storage conditions, potato tubers are readily infected and decomposed by anaerobic bacteria (Clostridium puniceum). We found that these anaerobic plant pathogens harbor a gene locus (type II polyketide synthase) to produce unusual polyketide metabolites (clostrubins) with dual functions. The clostrubins, which act as antibiotics against other microbial plant pathogens, enable the anaerobic bacteria to survive an oxygen-rich plant environment. PMID:26542569

  6. Microbiological study of pathogenic bacteria isolated from paediatric wound infections following the 2008 Wenchuan earthquake.

    PubMed

    Ran, Ying-Chun; Ao, Xiao-Xiao; Liu, Lan; Fu, Yi-Long; Tuo, Hui; Xu, Feng

    2010-05-01

    On 12 May 2008, the Wenchuan earthquake struck in Sichuan, China. Within 1 month after the earthquake, 98 injured children were admitted to the Children's Hospital of Chongqing Medical University. According to clinical manifestations, 50 children were diagnosed with wound infections. Wound secretions were cultured for bacteria. Pathogen distribution and drug resistance were analyzed. A total of 99 pathogens were isolated; 16 (16%) were Gram-positive bacteria and 81 (82%) were Gram-negative bacteria. The distribution of pathogens isolated within 1 month after the earthquake was different to the distribution of pathogens in 546 general hospitalized cases in the y before the earthquake. The pathogens most frequently isolated 1 month after the earthquake were Acinetobacter baumannii (27%), Enterobacter cloacae (18%) and Pseudomonas aeruginosa (13%). The pathogens most frequently isolated in the y prior to the earthquake were Escherichia coli (27%), Staphylococcus aureus (23%) and coagulase-negative staphylococci (9%). The rate of isolated drug-resistant bacteria was higher in the earthquake cases than in the general hospitalized cases. In the cases injured in the earthquake, the rates of isolation of methicillin-resistant Staphylococcus aureus and extended-spectrum beta-lactamase-producing E. cloacae, E. coli and Klebsiella pneumoniae were higher than in the cases from before the earthquake. Multidrug-resistant and pandrug-resistant A. baumannii were isolated at a higher rate in cases after the earthquake than in those before the earthquake. These changes in the spectrum of pathogens and in the drug resistance of the pathogens isolated following an earthquake will provide the basis for emergency treatment after earthquakes. PMID:20095936

  7. [Production of inhibiting plant growth and development hormones by pathogenic for legumes Pseudomonas genus bacteria].

    PubMed

    Dankevich, L A

    2013-01-01

    It has been studied the ability of pathogenic for legumes pathovars of Pseudomonas genus to produce ethylene and abscisic acid in vitro. A direct correlation between the level of ethylene production by agent of bacterial pea burn--Pseudomonas syringae pv. pisi and level of its aggressiveness for plants has been found. It is shown that the amount of abscisic acid synthesized by pathogenic for legumes Pseudomonas genus bacteria correlates with their aggressiveness for plants.

  8. Temperature-dependent expression of virulence genes in fish-pathogenic bacteria

    PubMed Central

    Guijarro, José A.; Cascales, Desirée; García-Torrico, Ana I.; García-Domínguez, Mario; Méndez, Jessica

    2015-01-01

    Virulence gene expression in pathogenic bacteria is modulated by environmental parameters. A key factor in this expression is temperature. Its effect on virulence gene expression in bacteria infecting warm-blooded hosts is well documented. Transcription of virulence genes in these bacteria is induced upon a shift from low environmental to a higher host temperature (37°C). Interestingly, host temperatures usually correspond to the optimum for growth of these pathogenic bacteria. On the contrary, in ectothermic hosts such as fish, molluscs, and amphibians, infection processes generally occur at a temperature lower than that for the optimal growth of the bacteria. Therefore, regulation of virulence gene expression in response to temperature shift has to be modulated in a different way to that which is found in bacteria infecting warm-blooded hosts. The current understanding of virulence gene expression and its regulation in response to temperature in fish-pathogenic bacteria is limited, but constant extension of our knowledge base is essential to enable a rational approach to the problem of the bacterial fish diseases affecting the aquaculture industry. This is an interesting issue and progress needs to be made in order to diminish the economic losses caused by these diseases. The intention of this review is, for the first time, to compile the scattered results existing in the field in order to lay the groundwork for future research. This article is an overview of those relevant virulence genes that are expressed at temperatures lower than that for optimal bacterial growth in different fish-pathogenic bacteria as well as the principal mechanisms that could be involved in their regulation. PMID:26217329

  9. Detection of Foodborne Pathogenic Bacteria using Bacteriophage Tail Spike Proteins

    NASA Astrophysics Data System (ADS)

    Poshtiban, Somayyeh

    Foodborne infections are worldwide health problem with tremendous social and financial impacts. Efforts are focused on developing accurate and reliable technologies for detection of food contaminations in early stages preferably on-site. This thesis focuses on interfacing engineering and biology by combining phage receptor binding proteins (RBPs) with engineered platforms including microresonator-based biosensors, magnetic particles and polymerase chain reaction (PCR) to develop bacterial detection sensors. We used phage RBPs as target specific bioreceptors to develop an enhanced microresonator array for bacterial detection. These resonator beams are optimized to feature a high natural frequency while offer large surface area for capture of bacteria. Theoretical analysis indicates a high mass sensitivity with a threshold for the detection of a single bacterial cell. We used phage RBPs as target specific bioreceptors, and successfully demonstrated the application of these phage RBB-immobilized arrays for specific detection of C. jejuni cells. We also developed a RBP-derivatized magnetic pre-enrichment method as an upstream sample preparation method to improve sensitivity and specificity of PCR for detection of bacterial cells in various food samples. The combination of RBP-based magnetic separation and real-time PCR allowed the detection of small number of bacteria in artificially contaminated food samples without any need for time consuming pre-enrichment step through culturing. We also looked into integration of the RBP-based magnetic separation with PCR onto a single microfluidic lab-on-a-chip to reduce the overall turnaround time.

  10. Commonalities and differences of T3SSs in rhizobia and plant pathogenic bacteria

    PubMed Central

    Tampakaki, Anastasia P.

    2014-01-01

    Plant pathogenic bacteria and rhizobia infect higher plants albeit the interactions with their hosts are principally distinct and lead to completely different phenotypic outcomes, either pathogenic or mutualistic, respectively. Bacterial protein delivery to plant host plays an essential role in determining the phenotypic outcome of plant-bacteria interactions. The involvement of type III secretion systems (T3SSs) in mediating animal- and plant-pathogen interactions was discovered in the mid-80's and is now recognized as a multiprotein nanomachine dedicated to trans-kingdom movement of effector proteins. The discovery of T3SS in bacteria with symbiotic lifestyles broadened its role beyond virulence. In most T3SS-positive bacterial pathogens, virulence is largely dependent on functional T3SSs, while in rhizobia the system is dispensable for nodulation and can affect positively or negatively the mutualistic associations with their hosts. This review focuses on recent comparative genome analyses in plant pathogens and rhizobia that uncovered similarities and variations among T3SSs in their genetic organization, regulatory networks and type III secreted proteins and discusses the evolutionary adaptations of T3SSs and type III secreted proteins that might account for the distinguishable phenotypes and host range characteristics of plant pathogens and symbionts. PMID:24723933

  11. Current Perspectives on Viable but Non-Culturable (VBNC) Pathogenic Bacteria

    PubMed Central

    Ramamurthy, Thandavarayan; Ghosh, Amit; Pazhani, Gururaja P.; Shinoda, Sumio

    2014-01-01

    Under stress conditions, many species of bacteria enter into starvation mode of metabolism or a physiologically viable but non-culturable (VBNC) state. Several human pathogenic bacteria have been reported to enter into the VBNC state under these conditions. The pathogenic VBNC bacteria cannot be grown using conventional culture media, although they continue to retain their viability and express their virulence. Though there have been debates on the VBNC concept in the past, several molecular studies have shown that not only can the VBNC state be induced under in vitro conditions but also that resuscitation from this state is possible under appropriate conditions. The most notable advance in resuscitating VBNC bacteria is the discovery of resuscitation-promoting factor (Rpf), which is a bacterial cytokines found in both Gram-positive and Gram-negative organisms. VBNC state is a survival strategy adopted by the bacteria, which has important implication in several fields, including environmental monitoring, food technology, and infectious disease management; and hence it is important to investigate the association of bacterial pathogens under VBNC state and the water/foodborne outbreaks. In this review, we describe various aspects of VBNC bacteria, which include their proteomic and genetic profiles under the VBNC state, conditions of resuscitation, methods of detection, antibiotic resistance, and observations on Rpf. PMID:25133139

  12. Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions

    PubMed Central

    Ton, Jurriaan; Brandenburg, Anna; Karlen, Danielle; Zopfi, Jakob; Turlings, Ted C. J.

    2014-01-01

    Volatile organic compounds (VOCs) released by soil microorganisms influence plant growth and pathogen resistance. Yet, very little is known about their influence on herbivores and higher trophic levels. We studied the origin and role of a major bacterial VOC, 2,3-butanediol (2,3-BD), on plant growth, pathogen and herbivore resistance, and the attraction of natural enemies in maize. One of the major contributors to 2,3-BD in the headspace of soil-grown maize seedlings was identified as Enterobacter aerogenes, an endophytic bacterium that colonizes the plants. The production of 2,3-BD by E. aerogenes rendered maize plants more resistant against the Northern corn leaf blight fungus Setosphaeria turcica. On the contrary, E. aerogenes-inoculated plants were less resistant against the caterpillar Spodoptera littoralis. The effect of 2,3-BD on the attraction of the parasitoid Cotesia marginiventris was more variable: 2,3-BD application to the headspace of the plants had no effect on the parasitoids, but application to the soil increased parasitoid attraction. Furthermore, inoculation of seeds with E. aerogenes decreased plant attractiveness, whereas inoculation of soil with a total extract of soil microbes increased parasitoid attraction, suggesting that the effect of 2,3-BD on the parasitoid is indirect and depends on the composition of the microbial community. PMID:24127750

  13. Evaluating the Growth Potential of Pathogenic Bacteria in Water ▿ †

    PubMed Central

    Vital, Marius; Stucki, David; Egli, Thomas; Hammes, Frederik

    2010-01-01

    The degree to which a water sample can potentially support the growth of human pathogens was evaluated. For this purpose, a pathogen growth potential (PGP) bioassay was developed based on the principles of conventional assimilable organic carbon (AOC) determination, but using pure cultures of selected pathogenic bacteria (Escherichia coli O157, Vibrio cholerae, or Pseudomonas aeruginosa) as the inoculum. We evaluated 19 water samples collected after different treatment steps from two drinking water production plants and a wastewater treatment plant and from ozone-treated river water. Each pathogen was batch grown to stationary phase in sterile water samples, and the concentration of cells produced was measured using flow cytometry. In addition, the fraction of AOC consumed by each pathogen was estimated. Pathogen growth did not correlate with dissolved organic carbon (DOC) concentration and correlated only weakly with the concentration of AOC. Furthermore, the three pathogens never grew to the same final concentration in any water sample, and the relative ratio of the cultures to each other was unique in each sample. These results suggest that the extent of pathogen growth is affected not only by the concentration but also by the composition of AOC. Through this bioassay, PGP can be included as a parameter in water treatment system design, control, and operation. Additionally, a multilevel concept that integrates the results from the bioassay into the bigger framework of pathogen growth in water is discussed. The proposed approach provides a first step for including pathogen growth into microbial risk assessment. PMID:20693455

  14. Antimicrobial activity of the carnivorous plant Dionaea muscipula against food-related pathogenic and putrefactive bacteria.

    PubMed

    Ogihara, Hirokazu; Endou, Fumiko; Furukawa, Soichi; Matsufuji, Hiroshi; Suzuki, Kouichi; Anzai, Hiroshi

    2013-01-01

    Solvent extracts from the carnivorous plant Dionaea muscipula (Venus flytrap) were prepared using eight different organic solvents, and examined for antibacterial activity against food-related pathogenic and putrefactive bacteria. All solvent extracts showed higher antibacterial activity against gram positive bacteria than against gram negative bacteria. The TLC-bioautography analysis of the extracts revealed that a yellow spot was detected at Rf value of 0.85, which showed strong antibacterial activity. The UV, MS, and NMR analyses revealed that the antibacterial compound was plumbagin. PMID:24077538

  15. Antimicrobial activity of the carnivorous plant Dionaea muscipula against food-related pathogenic and putrefactive bacteria.

    PubMed

    Ogihara, Hirokazu; Endou, Fumiko; Furukawa, Soichi; Matsufuji, Hiroshi; Suzuki, Kouichi; Anzai, Hiroshi

    2013-01-01

    Solvent extracts from the carnivorous plant Dionaea muscipula (Venus flytrap) were prepared using eight different organic solvents, and examined for antibacterial activity against food-related pathogenic and putrefactive bacteria. All solvent extracts showed higher antibacterial activity against gram positive bacteria than against gram negative bacteria. The TLC-bioautography analysis of the extracts revealed that a yellow spot was detected at Rf value of 0.85, which showed strong antibacterial activity. The UV, MS, and NMR analyses revealed that the antibacterial compound was plumbagin.

  16. Nature-inspired magnetoelastic biosentinels for the detection of pathogenic bacteria in stagnant liquids

    NASA Astrophysics Data System (ADS)

    Horikawa, Shin; Chai, Yating; Wikle, Howard C.; Dai, Jing; Hu, Jiajia; Suh, Sang-Jin; Vodyanoy, Vitaly; Chin, Bryan A.

    2015-05-01

    This paper presents an investigation into magnetoelastic (ME) biosentinels that capture and detect low-concentration pathogenic bacteria in stagnant liquids. The ME biosentinels are designed to mimic a variety of white blood cell types, known as the main defensive mechanism in the human body against different pathogenic invaders. The ME biosentinels are composed of a freestanding ME resonator coated with an engineered phage that specifically binds with the pathogens of interest. These biosentinels are ferromagnetic and thus can be moved through a liquid by externally applied magnetic fields. In addition, when a time-varying magnetic field is applied, the ME biosentinels can be placed into mechanical resonance by magnetostriction. As soon as the biosentinels bind with the target pathogen through the phage-based biomolecular recognition, a change in the biosentinel's resonant frequency occurs, and thereby the presence of the target pathogen can be detected. Detection of Bacillus anthracis spores under stagnant flow conditions was demonstrated.

  17. The Landscape of Realized Homologous Recombination in Pathogenic Bacteria

    PubMed Central

    Yahara, Koji; Didelot, Xavier; Jolley, Keith A.; Kobayashi, Ichizo; Maiden, Martin C.J.; Sheppard, Samuel K.; Falush, Daniel

    2016-01-01

    Recombination enhances the adaptive potential of organisms by allowing genetic variants to be tested on multiple genomic backgrounds. Its distribution in the genome can provide insight into the evolutionary forces that underlie traits, such as the emergence of pathogenicity. Here, we examined landscapes of realized homologous recombination of 500 genomes from ten bacterial species and found all species have “hot” regions with elevated rates relative to the genome average. We examined the size, gene content, and chromosomal features associated with these regions and the correlations between closely related species. The recombination landscape is variable and evolves rapidly. For example in Salmonella, only short regions of around 1 kb in length are hot whereas in the closely related species Escherichia coli, some hot regions exceed 100 kb, spanning many genes. Only Streptococcus pyogenes shows evidence for the positive correlation between GC content and recombination that has been reported for several eukaryotes. Genes with function related to the cell surface/membrane are often found in recombination hot regions but E. coli is the only species where genes annotated as “virulence associated” are consistently hotter. There is also evidence that some genes with “housekeeping” functions tend to be overrepresented in cold regions. For example, ribosomal proteins showed low recombination in all of the species. Among specific genes, transferrin-binding proteins are recombination hot in all three of the species in which they were found, and are subject to interspecies recombination. PMID:26516092

  18. [Prevention of bacterial risk: pathogen inactivation/detection of bacteria].

    PubMed

    Morel, P; Naegelen, C; Deschaseaux, M; Bardiaux, L

    2013-05-01

    Bacterial contamination of blood products remains the most important infectious risk of blood transfusion in 2013. Platelet concentrates (PC) are in cause in the majority of the transfusion reaction due to bacterial contaminations. A lot of prevention methods have been developed over the last 10 years (pre-donation interview, skin decontamination, diversion of the first 30 mL of the donation, leuko-reduction...), they have focused on limiting the contamination of the donations and prevent the bacterial growth in donations and/or in the blood products. These measures were effective and led to significantly reducing the risk of adverse effects associated with bacterial growth. However, every year there are about six accidents (with a high level of imputability) and one death. The reduction of the bacterial risk remains a priority for the French Blood Establishment (EFS). The procedure for skin disinfection is going to be improved in order to further strengthen this crucial step to avoid the contamination of donation. Methods of pathogen inactivation applied to plasma and PC are available in France and their effectiveness is demonstrated on the bacterial risk. Methods for bacterial detection of PC are used in many countries now. Automated culture is the most common. Alternatives are now available in the form of rapid tests able to analyze the PC just before the delivery and avoid false negatives observed with automated culture. Assessments are under way to confirm these benefits in 2013.

  19. Reinforcing effects of non-pathogenic bacteria and predation risk: from physiology to life history.

    PubMed

    Janssens, Lizanne; Stoks, Robby

    2014-10-01

    The important ecological role of predation risk in shaping populations, communities and ecosystems is becoming increasingly clear. In this context, synergistic effects between predation risk and other natural stressors on prey organisms are gaining attention. Although non-pathogenic bacteria can be widespread in aquatic ecosystems, their role in mediating effects of predation risk has been ignored. We here address the hypothesis that non-pathogenic bacteria may reinforce the negative effects of predation risk in larvae of the damselfly Coenagrion puella. We found synergistic effects for all three life history variables studied: mortality increased, growth reductions were magnified and bacterial load was higher when both non-lethal stressors were combined. The combined exposure to the bacterium and predation risk considerably impaired the two key antipredator mechanisms of the damselfly larvae: they no longer reduced their food intake under predation risk and showed a synergistic reduction in escape swimming speed. The reinforcing negative effects on the fitness-related traits could be explained by the observed synergistic effects on food intake, swimming muscle mass, immune function and oxidative damage. These are likely widespread consequences of energetic constraints and increased metabolic rates associated with the fight-or-flight response. We therefore hypothesize that the here documented synergistic interactions with non-pathogenic bacteria may be widespread. Our results highlight the ignored ecological role of non-pathogenic bacteria in reinforcing the negative effects of predation risk on prey organisms.

  20. Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria

    PubMed Central

    Castro, S.B.R.; Leal, C.A.G.; Freire, F.R.; Carvalho, D.A.; Oliveira, D.F.; Figueiredo, H.C.P.

    2008-01-01

    The aim of this work was to evaluate the antibacterial activity of Brazilian plants extracts against fish pathogenic bacteria. Forty six methanolic extracts were screened to identify their antibacterial properties against Streptococcus agalactiae, Flavobacterium columnare and Aeromonas hydrophila. Thirty one extracts showed antibacterial activity. PMID:24031303

  1. Hyperspectral microscope imaging methods to classify gram-positive and gram-negative foodborne pathogenic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An acousto-optic tunable filter-based hyperspectral microscope imaging method has potential for identification of foodborne pathogenic bacteria from microcolony rapidly with a single cell level. We have successfully developed the method to acquire quality hyperspectral microscopic images from variou...

  2. Classification of gram-positive and gram-negative foodborne pathogenic bacteria with hyperspectral microscope imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optical method with hyperspectral microscope imaging (HMI) has potential for identification of foodborne pathogenic bacteria from microcolonies rapidly with a cell level. A HMI system that provides both spatial and spectral information could be an effective tool for analyzing spectral characteristic...

  3. Reinforcing effects of non-pathogenic bacteria and predation risk: from physiology to life history.

    PubMed

    Janssens, Lizanne; Stoks, Robby

    2014-10-01

    The important ecological role of predation risk in shaping populations, communities and ecosystems is becoming increasingly clear. In this context, synergistic effects between predation risk and other natural stressors on prey organisms are gaining attention. Although non-pathogenic bacteria can be widespread in aquatic ecosystems, their role in mediating effects of predation risk has been ignored. We here address the hypothesis that non-pathogenic bacteria may reinforce the negative effects of predation risk in larvae of the damselfly Coenagrion puella. We found synergistic effects for all three life history variables studied: mortality increased, growth reductions were magnified and bacterial load was higher when both non-lethal stressors were combined. The combined exposure to the bacterium and predation risk considerably impaired the two key antipredator mechanisms of the damselfly larvae: they no longer reduced their food intake under predation risk and showed a synergistic reduction in escape swimming speed. The reinforcing negative effects on the fitness-related traits could be explained by the observed synergistic effects on food intake, swimming muscle mass, immune function and oxidative damage. These are likely widespread consequences of energetic constraints and increased metabolic rates associated with the fight-or-flight response. We therefore hypothesize that the here documented synergistic interactions with non-pathogenic bacteria may be widespread. Our results highlight the ignored ecological role of non-pathogenic bacteria in reinforcing the negative effects of predation risk on prey organisms. PMID:25103326

  4. [Detection of enteric pathogenic bacteria from surface waters by quantitative polymerase chain reaction (QPCR)].

    PubMed

    Liu, Yong-Jun; Zhang, Chong-Miao; Wang, Xiao-Chang; Lü, Ying-Jun; Zuo, Li-Li

    2008-05-01

    A rapid quantitative polymerase chain reaction (QPCR) analysis method with universal primers was developed to detect cell densities of the enteric pathogenic bacteria from 5 surface water of Xi'an City for 4 months continuously. And the detection results by QPCR method were compared with counts of coliforms colony-forming units (CFU) determined by membrane filter (MF) analysis. The results showed that QPCR method had an estimated 94% confidence, and detection limit was 2.7 Escherichia coli cells per sample in undiluted DNA extracts. For five surface waters (N = 60), the geometric mean of pathogenic bacteria concentration determined by QPCR was 2.2-5 times of corresponding coliform CFU determined by MF analysis. Using QPCR analysis, these geometric means of pathogenic bacteria concentration ranged from 25 CCE/100 mL to 67 000 CCE/100 mL. Using MF culture analysis, coliforms ranged from 3 CFU/100 mL to 45 000 CFU/100 mL. Regression analysis showed that there was a significant positive correlation between pathogenic bacteria determined by QPCR method and coliforms determined by MF method, the correlation coefficient (r) was 0.983.

  5. A COMPARISON OF THREE ASSAY PROCEDURES FOR DETERMINING CHLORINE INACTIVATION OF WATERBORNE PATHOGENIC BACTERIA

    EPA Science Inventory

    One criterion on which chlorine treatment of water may be based is the concentration (C) in mg/l multiplied by the time (t) in min of exposure or Ct values. We compared different Ct values on waterborne pathogenic bacteria by cultural assay for viability and 2 assays that mea...

  6. Inverted methoxypyridinium phthalocyanines for PDI of pathogenic bacteria.

    PubMed

    Lourenço, Leandro M O; Sousa, Andreina; Gomes, Maria C; Faustino, Maria A F; Almeida, Adelaide; Silva, Artur M S; Neves, Maria G P M S; Cavaleiro, José A S; Cunha, Ângela; Tomé, João P C

    2015-10-01

    Phthalocyanines (Pc) are photoactive molecules that can absorb and emit light in a large range of the UV-Vis spectrum with recognized potential for medical applications. Considering the biomedical applications an important limitation of these compounds is their low solubility in water. The use of suitable pyridinium groups on Pc is a good strategy to solve this drawback and to make them more effective to photoinactivate Gram-negative bacteria via a photodynamic inactivation (PDI) approach. Herein, an easy synthetic access to obtain inverted tetra- and octa-methoxypyridinium phthalocyanines (compounds 5 and 6) and also their efficiency to photoinactivate a recombinant bioluminescent strain of Escherichia coli is described. The obtained results were compared with the ones obtained when more conventional thiopyridinium phthalocyanines (compounds 7 and 8) were used. This innovative study comparing thiopyridinium and inverted methoxypyridinium moieties on cationic Pc is reported for the first time taking into account the efficiency of singlet oxygen ((1)O2) generation, water solubility and uptake properties.

  7. Pathogen-free screening of bacteria-specific hybridomas for selecting high-quality monoclonal antibodies against pathogen bacteria as illustrated for Legionella pneumophila.

    PubMed

    Féraudet-Tarisse, Cécile; Vaisanen-Tunkelrott, Marja-Liisa; Moreau, Karine; Lamourette, Patricia; Créminon, Christophe; Volland, Hervé

    2013-05-31

    Antibodies are potent biological tools increasingly used as detection, diagnostic and therapeutic reagents. Many technological advances have optimized and facilitated production and screening of monoclonal antibodies. We report here an original method to screen for antibodies targeting biosafety level 2 or 3 pathogens without the fastidious handling inherent to pathogen use. A double ELISA screening was performed using as coated antigen transformed Escherichia coli expressing at its surface a protein specific to the pathogenic bacteria versus control untransformed E. coli. This method was applied to Legionella, using the surface-exposed Mip protein (macrophage infectivity potentiator). This screening proved to be an excellent means of selecting mAbs that bind Legionella pneumophila 1 surface-exposed Mip protein. This method also appears more biologically relevant than screening using the recombinant Mip protein alone and less tedious than a test performed directly on Legionella bacteria. We obtained 21 mAbs that bind strongly to L. pneumophila serogroups 1 to 13, and we validated their use in a rapid ELISA (performed in 4.5 h) and an immunochromatographic test (20 min).

  8. Identification of DNA Methyltransferase Genes in Human Pathogenic Bacteria by Comparative Genomics.

    PubMed

    Brambila-Tapia, Aniel Jessica Leticia; Poot-Hernández, Augusto Cesar; Perez-Rueda, Ernesto; Rodríguez-Vázquez, Katya

    2016-06-01

    DNA methylation plays an important role in gene expression and virulence in some pathogenic bacteria. In this report, we describe DNA methyltransferases (MTases) present in human pathogenic bacteria and compared them with related species, which are not pathogenic or less pathogenic, based in comparative genomics. We performed a search in the KEGG database of the KEGG database orthology groups associated with adenine and cytosine DNA MTase activities (EC: 2.1.1.37, EC: 2.1.1.113 and EC: 2.1.1.72) in 37 human pathogenic species and 18 non/less pathogenic relatives and performed comparisons of the number of these MTases sequences according to their genome size, the DNA MTase type and with their non-less pathogenic relatives. We observed that Helicobacter pylori and Neisseria spp. presented the highest number of MTases while ten different species did not present a predicted DNA MTase. We also detected a significant increase of adenine MTases over cytosine MTases (2.19 vs. 1.06, respectively, p < 0.001). Adenine MTases were the only MTases associated with restriction modification systems and DNA MTases associated with type I restriction modification systems were more numerous than those associated with type III restriction modification systems (0.84 vs. 0.17, p < 0.001); additionally, there was no correlation with the genome size and the total number of DNA MTases, indicating that the number of DNA MTases is related to the particular evolution and lifestyle of specific species, regulating the expression of virulence genes in some pathogenic bacteria.

  9. Identification of DNA Methyltransferase Genes in Human Pathogenic Bacteria by Comparative Genomics.

    PubMed

    Brambila-Tapia, Aniel Jessica Leticia; Poot-Hernández, Augusto Cesar; Perez-Rueda, Ernesto; Rodríguez-Vázquez, Katya

    2016-06-01

    DNA methylation plays an important role in gene expression and virulence in some pathogenic bacteria. In this report, we describe DNA methyltransferases (MTases) present in human pathogenic bacteria and compared them with related species, which are not pathogenic or less pathogenic, based in comparative genomics. We performed a search in the KEGG database of the KEGG database orthology groups associated with adenine and cytosine DNA MTase activities (EC: 2.1.1.37, EC: 2.1.1.113 and EC: 2.1.1.72) in 37 human pathogenic species and 18 non/less pathogenic relatives and performed comparisons of the number of these MTases sequences according to their genome size, the DNA MTase type and with their non-less pathogenic relatives. We observed that Helicobacter pylori and Neisseria spp. presented the highest number of MTases while ten different species did not present a predicted DNA MTase. We also detected a significant increase of adenine MTases over cytosine MTases (2.19 vs. 1.06, respectively, p < 0.001). Adenine MTases were the only MTases associated with restriction modification systems and DNA MTases associated with type I restriction modification systems were more numerous than those associated with type III restriction modification systems (0.84 vs. 0.17, p < 0.001); additionally, there was no correlation with the genome size and the total number of DNA MTases, indicating that the number of DNA MTases is related to the particular evolution and lifestyle of specific species, regulating the expression of virulence genes in some pathogenic bacteria. PMID:27570304

  10. Pathogen translocation and histopathological lesions in an experimental model of Salmonella Dublin infection in calves receiving lactic acid bacteria and lactose supplements

    PubMed Central

    Zbrun, María V.; Soto, Lorena P.; Bertozzi, Ezequiel; Sequeira, Gabriel J.; Marti, Luis E.; Signorini, Marcelo L.; Armesto, Roberto Rodríguez; Rosmini, Marcelo R.

    2012-01-01

    The purpose of this study was to evaluate the capacity of a lactic acid bacteria (LAB) inoculum to protect calves with or without lactose supplements against Salmonella Dublin infection by evaluating histopathological lesions and pathogen translocation. Fifteen calves were divided into three groups [control group (C-G), a group inoculated with LAB (LAB-G), and a group inoculated with LAB and given lactose supplements (L-LAB-G)] with five, six, and four animals, respectively. The inoculum, composed of Lactobacillus (L.) casei DSPV 318T, L. salivarius DSPV 315T, and Pediococcus acidilactici DSPV 006T, was administered with milk replacer. The LAB-G and L-LAB-G received a daily dose of 109 CFU/kg body weight of each strain throughout the experiment. Lactose was provided to the L-LAB-G in doses of 100 g/day. Salmonella Dublin (2 × 1010 CFU) was orally administered to all animals on day 11 of the experiment. The microscopic lesion index values in target organs were 83%, 70%, and 64.3% (p < 0.05) for the C-G, LAB-G, and L-LAB-G, respectively. Administration of the probiotic inoculum was not fully effective against infection caused by Salmonella. Although probiotic treatment was unable to delay the arrival of pathogen to target organs, it was evident that the inoculum altered the response of animals against pathogen infection. PMID:23000583

  11. N-acyl-homoserine lactones-producing bacteria protect plants against plant and human pathogens

    PubMed Central

    Hernández-Reyes, Casandra; Schenk, Sebastian T; Neumann, Christina; Kogel, Karl-Heinz; Schikora, Adam

    2014-01-01

    The implementation of beneficial microorganisms for plant protection has a long history. Many rhizobia bacteria are able to influence the immune system of host plants by inducing resistance towards pathogenic microorganisms. In this report, we present a translational approach in which we demonstrate the resistance-inducing effect of Ensifer meliloti (Sinorhizobium meliloti) on crop plants that have a significant impact on the worldwide economy and on human nutrition. Ensifer meliloti is usually associated with root nodulation in legumes and nitrogen fixation. Here, we suggest that the ability of S. meliloti to induce resistance depends on the production of the quorum-sensing molecule, oxo-C14-HSL. The capacity to enhanced resistance provides a possibility to the use these beneficial bacteria in agriculture. Using the Arabidopsis-Salmonella model, we also demonstrate that the application of N-acyl-homoserine lactones-producing bacteria could be a successful strategy to prevent plant-originated infections with human pathogens. PMID:25234390

  12. Bioaccumulation of pathogenic bacteria and amoeba by zebra mussels and their presence in watercourses.

    PubMed

    Mosteo, R; Goñi, P; Miguel, N; Abadías, J; Valero, P; Ormad, M P

    2016-01-01

    Dreissena polymorpha (the zebra mussel) has been invading freshwater bodies in Europe since the beginning of the nineteenth century. Filter-feeding organisms can accumulate and concentrate both chemical and biological contaminants in their tissues. Therefore, zebra mussels are recognized as indicators of freshwater quality. In this work, the capacity of the zebra mussel to accumulate human pathogenic bacteria and protozoa has been evaluated and the sanitary risk associated with their presence in surface water has also been assessed. The results show a good correlation between the pathogenic bacteria concentration in zebra mussels and in watercourses. Zebra mussels could therefore be used as an indicator of biological contamination. The bacteria (Escherichia coli, Enterococcus spp., Pseudomonas spp., and Salmonella spp.) and parasites (Cryptosporidium oocysts and free-living amoebae) detected in these mussels reflect a potential sanitary risk in water. PMID:26400243

  13. Bioaccumulation of pathogenic bacteria and amoeba by zebra mussels and their presence in watercourses.

    PubMed

    Mosteo, R; Goñi, P; Miguel, N; Abadías, J; Valero, P; Ormad, M P

    2016-01-01

    Dreissena polymorpha (the zebra mussel) has been invading freshwater bodies in Europe since the beginning of the nineteenth century. Filter-feeding organisms can accumulate and concentrate both chemical and biological contaminants in their tissues. Therefore, zebra mussels are recognized as indicators of freshwater quality. In this work, the capacity of the zebra mussel to accumulate human pathogenic bacteria and protozoa has been evaluated and the sanitary risk associated with their presence in surface water has also been assessed. The results show a good correlation between the pathogenic bacteria concentration in zebra mussels and in watercourses. Zebra mussels could therefore be used as an indicator of biological contamination. The bacteria (Escherichia coli, Enterococcus spp., Pseudomonas spp., and Salmonella spp.) and parasites (Cryptosporidium oocysts and free-living amoebae) detected in these mussels reflect a potential sanitary risk in water.

  14. Muc2 Protects against Lethal Infectious Colitis by Disassociating Pathogenic and Commensal Bacteria from the Colonic Mucosa

    PubMed Central

    Bergstrom, Kirk S. B.; Kissoon-Singh, Vanessa; Gibson, Deanna L.; Ma, Caixia; Montero, Marinieve; Sham, Ho Pan; Ryz, Natasha; Huang, Tina; Velcich, Anna; Finlay, B. Brett; Chadee, Kris; Vallance, Bruce A.

    2010-01-01

    Despite recent advances in our understanding of the pathogenesis of attaching and effacing (A/E) Escherichia coli infections, the mechanisms by which the host defends against these microbes are unclear. The goal of this study was to determine the role of goblet cell-derived Muc2, the major intestinal secretory mucin and primary component of the mucus layer, in host protection against A/E pathogens. To assess the role of Muc2 during A/E bacterial infections, we inoculated Muc2 deficient (Muc2−/−) mice with Citrobacter rodentium, a murine A/E pathogen related to diarrheagenic A/E E. coli. Unlike wildtype (WT) mice, infected Muc2−/− mice exhibited rapid weight loss and suffered up to 90% mortality. Stool plating demonstrated 10–100 fold greater C. rodentium burdens in Muc2−/− vs. WT mice, most of which were found to be loosely adherent to the colonic mucosa. Histology of Muc2−/− mice revealed ulceration in the colon amid focal bacterial microcolonies. Metabolic labeling of secreted mucins in the large intestine demonstrated that mucin secretion was markedly increased in WT mice during infection compared to uninfected controls, suggesting that the host uses increased mucin release to flush pathogens from the mucosal surface. Muc2 also impacted host-commensal interactions during infection, as FISH analysis revealed C. rodentium microcolonies contained numerous commensal microbes, which was not observed in WT mice. Orally administered FITC-Dextran and FISH staining showed significantly worsened intestinal barrier disruption in Muc2−/− vs. WT mice, with overt pathogen and commensal translocation into the Muc2−/− colonic mucosa. Interestingly, commensal depletion enhanced C. rodentium colonization of Muc2−/− mice, although colonic pathology was not significantly altered. In conclusion, Muc2 production is critical for host protection during A/E bacterial infections, by limiting overall pathogen and commensal numbers associated with the colonic

  15. Applicability of photodynamic antimicrobial chemotherapy as an alternative to inactivate fish pathogenic bacteria in aquaculture systems.

    PubMed

    Arrojado, Cátia; Pereira, Carla; Tomé, João P C; Faustino, Maria A F; Neves, Maria G P M S; Tomé, Augusto C; Cavaleiro, José A S; Cunha, Angela; Calado, Ricardo; Gomes, Newton C M; Almeida, Adelaide

    2011-10-01

    Aquaculture activities are increasing worldwide, stimulated by the progressive reduction of natural fish stocks in the oceans. However, these activities also suffer heavy production and financial losses resulting from fish infections caused by microbial pathogens, including multidrug resistant bacteria. Therefore, strategies to control fish infections are urgently needed, in order to make aquaculture industry more sustainable. Antimicrobial photodynamic therapy (aPDT) has emerged as an alternative to treat diseases and prevent the development of antibiotic resistance by pathogenic bacteria. The aim of this work was to evaluate the applicability of aPDT to inactivate pathogenic fish bacteria. To reach this objective a cationic porphyrin Tri-Py(+)-Me-PF was tested against nine pathogenic bacteria isolated from a semi-intensive aquaculture system and against the cultivable bacteria of the aquaculture system. The ecological impact of aPDT in the aquatic environment was also tested on the natural bacterial community, using the overall bacterial community structure and the cultivable bacteria as indicators. Photodynamic inactivation of bacterial isolates and of cultivable bacteria was assessed counting the number of colonies. The impact of aPDT in the overall bacterial community structure of the aquaculture water was evaluated by denaturing gel gradient electrophoresis (DGGE). The results showed that, in the presence of Tri-Py(+)-Me-PF, the growth of bacterial isolates was inhibited, resulting in a decrease of ≈7-8 log after 60-270 min of irradiation. Cultivable bacteria were also considerably affected, showing decreases up to the detection limit (≈2 log decrease on cell survival), but the inactivation rate varied significantly with the sampling period. The DGGE fingerprint analyses revealed changes in the bacterial community structure caused by the combination of aPDT and light. The results indicate that aPDT can be regarded as a new approach to control fish

  16. Prevention of leucaena toxicosis of cattle in Florida by ruminal inoculation with 3-hydroxy-4-(1H)-pyridone-degrading bacteria.

    PubMed

    Hammond, A C; Allison, M J; Williams, M J; Prine, G M; Bates, D B

    1989-12-01

    Ruminal microorganisms in cattle at a Florida agriculture research station did not have the ability to detoxify leucaena by degradation of 3-hydroxy-4(1H)-pyridone (3,4,-DHP), but a DHP isomer (2,3-DHP) was degraded in some cattle. Cattle with microorganisms that degraded 2,3-DHP were mostly Senepol cattle imported from St. Croix, US Virgin Islands, where leucaena is an indigenous species. Hereford cattle at the research station in Florida generally did not degrade 3,4-DHP or 2,3-DHP. An experiment was conducted in which a pure culture of 3,4-DHP-degrading bacteria was inoculated into Hereford cattle (with ruminal fistula) grazing leucaena. The bacteria successfully colonized the rumen of recipient cattle and persisted through the following winter when there was no leucaena in the diet. PMID:2610447

  17. Salicylic acid induction-deficient mutants of Arabidopsis express PR-2 and PR-5 and accumulate high levels of camalexin after pathogen inoculation.

    PubMed Central

    Nawrath, C; Métraux, J P

    1999-01-01

    In Arabidopsis, systemic acquired resistance against pathogens has been associated with the accumulation of salicylic acid (SA) and the expression of the pathogenesis-related proteins PR-1, PR-2, and PR-5. We report here the isolation of two nonallelic mutants impaired in the pathway leading to SA biosynthesis. These SA induction-deficient (sid) mutants do not accumulate SA after pathogen inoculation and are more susceptible to both virulent and avirulent forms of Pseudomonas syringae and Peronospora parasitica. However, sid mutants are not as susceptible to these pathogens as are transgenic plants expressing the nahG gene encoding an SA hydroxylase that degrades SA to catechol. In contrast to NahG plants, only the expression of PR-1 is strongly reduced in sid mutants, whereas PR-2 and PR-5 are still expressed after pathogen attack. Furthermore, the accumulation of the phytoalexin camalexin is normal. These results indicate that SA-independent compensation pathways that do not operate in NahG plants are active in sid mutants. One of the mutants is allelic to eds5 (for enhanced disease susceptibility), whereas the other mutant has not been described previously. PMID:10449575

  18. Characterization of plant growth-promoting traits of free-living diazotrophic bacteria and their inoculation effects on growth and nitrogen uptake of crop plants.

    PubMed

    Islam, Md Rashedul; Madhaiyan, M; Deka Boruah, Hari P; Yim, Woojong; Lee, Gillseung; Saravanan, V S; Fu, Qingling; Hu, Hongqing; Sa, Tongmin

    2009-10-01

    The search for diverse plant growth-promoting (PGP) diazotrophic bacteria is gaining momentum as efforts are made to exploit them as biofertilizers for various economically important crops. In the present study, 17 diazotrophic strains belonging to eight different genera isolated from rice paddy fields were screened for multiple PGP traits and evaluated for their inoculation effects on canola and rice plants. All of the strains tested positive for 1- aminocyclopropane-1-carboxylate (ACC) deaminase activity and production of indole 3-acetic acid (IAA) and ammonia (NH3). Additionally, four of the strains were able to solubilize phosphorus (P), five tested positive for zinc (Zn) solubilization and sulfur (S) oxidation, and eight strains produced siderophores. Based on the presence of multiple PGP traits, 10 strains were selected for inoculation studies. Treatment with Herbaspirillum sp. RFNB26 resulted in maximum root length (54.3%), seedling vigor, and dry biomass in canola, whereas Paenibacillus sp. RFNB4 exhibited the lowest activity under gnotobiotic conditions. However, under pot culture conditions, Paenibacillus sp. RFNB4 significantly increased plant height and dry biomass production by 42.3% and 29.5%, respectively. Canola plants and rhizosphere soils inoculated with Bacillus sp. RFNB6 exhibited significantly higher nitrogenase activity. In greenhouse experiments, Serratia sp. RFNB18 increased rice plant height by 35.1%, Xanthomonas sp. RFNB24 enhanced biomass production by 84.6%, and rice rhizosphere soils inoculated with Herbaspirillum sp. RFNB26 exhibited the highest nitrogenase activity. Our findings indicate that most of the selected strains possess multiple PGP properties that significantly improve the growth parameters of the two plants when tested under controlled conditions.

  19. Effect of lactic acid bacteria inoculant and beet pulp addition on fermentation characteristics and in vitro ruminal digestion of vegetable residue silage.

    PubMed

    Cao, Y; Cai, Y; Takahashi, T; Yoshida, N; Tohno, M; Uegaki, R; Nonaka, K; Terada, F

    2011-08-01

    The objective of this study was to determine the effect of beet pulp (BP) and lactic acid bacteria (LAB) on silage fermentation quality and in vitro ruminal dry matter (DM) digestion of vegetable residues, including white cabbage, Chinese cabbage, red cabbage, and lettuce. Silage was prepared using a small-scale fermentation system, and treatments were designed as control silage without additive or with BP (30% fresh matter basis), LAB inoculant Chikuso-1 (Lactobacillus plantarum, 5mg/kg, fresh matter basis), and BP+LAB. In vitro incubation was performed using rumen fluid mixed with McDougall's artificial saliva (at a ratio of 1:4, vol/vol) at 39°C for 6h to determine the ruminal fermentability of the vegetable residue silages. These vegetable residues contained high levels of crude protein (20.6-22.8% of DM) and moderate levels of neutral detergent fiber (22.7-33.6% of DM). In all silages, the pH sharply decreased and lactic acid increased, and the growth of bacilli, coliform bacteria, molds, and yeasts was inhibited by the low pH at the early stage of ensiling. The silage treated with BP or LAB had a lower pH and a higher lactic acid content than the control silage. After 6h of incubation, all silages had relatively high DM digestibility (38.6-44.9%); in particular, the LAB-inoculated silage had the highest DM digestibility and the lowest methane production. The vegetable residues had high nutritional content and high in vitro DM digestibility. Also, both the addition of a LAB inoculant and moisture adjustment with BP improved the fermentation quality of the vegetable residue silages. In addition, LAB increased DM digestibility and decreased ruminal methane production. PMID:21787927

  20. Effect of silver ion coating of fixed orthodontic retainers on the growth of oral pathogenic bacteria.

    PubMed

    Morita, Yusuke; Imai, Susumu; Hanyuda, Ai; Matin, Khairul; Hanada, Nobuhiro; Nakamura, Yoshiki

    2014-01-01

    Titanium and stainless steel wires used for retainers in orthodontic procedures were coated with Ag ions and the effects of the coating on common oral pathogens and their pathogenicity were investigated. Two species of cariogenic and three species of periodontopathic bacteria were assessed. Biofilms of Streptococcus sobrinus and two VSC gases produced by P. gingivalis were also examined. Ag ion-coated wires showed marked antibacterial activities compared with uncoated wires; in most cases, the differences were statistically significant (p<0.05). All Ag ion-coated wires (Ti+ and SS+ wires) displayed more than 2-mm diameter bacteria growth-resistant zones around them in radial diffusion tests. Ag ion release was 0.043±0.005 ppm in 24 h that didn't show cytotoxicity. Thus, these results suggest that a simple Ag ion coating on pure titanium and stainless steel wires can restrict growth and pathogenic activities of oral pathogenic bacteria, even in the early stages of culture.

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

    PubMed Central

    2014-01-01

    Background The antibiotic resistance of pathogenic microorganisms is a worldwide problem. Each year several million people across the world acquire infections with bacteria that are antibiotic-resistant, which is costly in terms of human health. New antibiotics are extremely needed to overcome the current resistance problem. Results Transgenic flax plants overproducing compounds from phenylpropanoid pathway accumulate phenolic derivatives of potential antioxidative, and thus, antimicrobial activity. Alkali hydrolyzed seedcake extract containing coumaric acid, ferulic acid, caffeic acid, and lignan in high quantities was used as an assayed against pathogenic bacteria (commonly used model organisms and clinical strains). It was shown that the extract components had antibacterial activity, which might be useful as a prophylactic against bacterial infection. Bacteria topoisomerase II (gyrase) inhibition and genomic DNA disintegration are suggested to be the main reason for rendering antibacterial action. Conclusions The data obtained strongly suggest that the seedcake extract preparation is a suitable candidate for antimicrobial action with a broad spectrum and partial selectivity. Such preparation can be applied in cases where there is a risk of multibacterial infection and excellent answer on global increase in multidrug resistance in pathogenic bacteria. PMID:25073883

  2. Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria.

    PubMed

    Lambrecht, Ellen; Baré, Julie; Chavatte, Natascha; Bert, Wim; Sabbe, Koen; Houf, Kurt

    2015-08-15

    The production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, and Listeria monocytogenes) survive inside cysts of the ubiquitous amoeba Acanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, with Salmonella enterica surviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed. PMID:26070667

  3. Nisin and class IIa bacteriocin resistance among Listeria and other foodborne pathogens and spoilage bacteria.

    PubMed

    Kaur, Gurpreet; Malik, Ravinder Kumar; Mishra, Santosh Kumar; Singh, Tejinder Pal; Bhardwaj, Arun; Singroha, Garima; Vij, Shilpa; Kumar, Naresh

    2011-06-01

    Food safety has been an important issue globally due to increasing foodborne diseases and change in food habits. To inactivate foodborne pathogens, various novel technologies such as biopreservation systems have been studied. Bacteriocins are ribosomally synthesized peptides or proteins with antimicrobial activity produced by different groups of bacteria, but the bacteriocins produced by many lactic acid bacteria offer potential applications in food preservation. The use of bacteriocins in the food industry can help reduce the addition of chemical preservatives as well as the intensity of heat treatments, resulting in foods that are more naturally preserved. However, the development of highly tolerant and/or resistant strains may decrease the efficiency of bacteriocins as biopreservatives. Several mechanisms of bacteriocin resistance development have been proposed among various foodborne pathogens. The acquiring of resistance to bacteriocins can significantly affect physiological activity profile of bacteria, alter cell-envelope lipid composition, and also modify the antibiotic susceptibility/resistance profile of bacteria. This article presents a brief review on the scientific research about the various possible mechanisms involved in the development of resistance to nisin and Class IIa bacteriocins among the foodborne pathogens.

  4. Incidence of Bacteriocins Produced by Food-Related Lactic Acid Bacteria Active towards Oral Pathogens.

    PubMed

    Zoumpopoulou, Georgia; Pepelassi, Eudoxie; Papaioannou, William; Georgalaki, Marina; Maragkoudakis, Petros A; Tarantilis, Petros A; Polissiou, Moschos; Tsakalidou, Effie; Papadimitriou, Konstantinos

    2013-02-26

    In the present study we investigated the incidence of bacteriocins produced by 236 lactic acid bacteria (LAB) food isolates against pathogenic or opportunistic pathogenic oral bacteria. This set of LAB contained several strains (≥17%) producing bacteriocins active against food-related bacteria. Interestingly only Streptococcus macedonicus ACA-DC 198 was able to inhibit the growth of Streptococcus oralis, Streptococcus sanguinis and Streptococcus gordonii, while Lactobacillus fermentum ACA-DC 179 and Lactobacillus plantarun ACA-DC 269 produced bacteriocins solely against Streptococcus oralis. Thus, the percentage of strains that were found to produce bacteriocins against oral bacteria was ~1.3%. The rarity of bacteriocins active against oral LAB pathogens produced by food-related LAB was unexpected given their close phylogenetic relationship. Nevertheless, when tested in inhibition assays, the potency of the bacteriocin(s) of S. macedonicus ACA-DC 198 against the three oral streptococci was high. Fourier-transform infrared spectroscopy combined with principal component analysis revealed that exposure of the target cells to the antimicrobial compounds caused major alterations of key cellular constituents. Our findings indicate that bacteriocins produced by food-related LAB against oral LAB may be rare, but deserve further investigation since, when discovered, they can be effective antimicrobials.

  5. Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria

    PubMed Central

    Lambrecht, Ellen; Baré, Julie; Chavatte, Natascha; Bert, Wim; Sabbe, Koen

    2015-01-01

    The production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, and Listeria monocytogenes) survive inside cysts of the ubiquitous amoeba Acanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, with Salmonella enterica surviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed. PMID:26070667

  6. Effectiveness of trisodium phosphate, acidified sodium chlorite, citric acid, and peroxyacids against pathogenic bacteria on poultry during refrigerated storage.

    PubMed

    del Río, Elena; Muriente, Rebeca; Prieto, Miguel; Alonso-Calleja, Carlos; Capita, Rosa

    2007-09-01

    The effects of dipping treatments (15 min) in potable water or in solutions (wt/vol) of 12% trisodium phosphate (TSP), 1,200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), and 220 ppm peroxyacids (PA) on inoculated pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Salmonella Enteritidis, Escherichia coli, and Yersinia enterocolitica) and skin pH were investigated throughout storage of chicken legs (days 0, 1, 3, and 5) at 3 +/- 1 degrees C. All chemical solutions reduced microbial populations (P < 0.001) as compared with the control (untreated) samples. Similar bacterial loads (P > 0.05) were observed on water-dipped and control legs. Type of treatment, microbial group, and sampling day influenced microbial counts (P < 0.001). Average reductions with regard to control samples were 0.28 to 2.41 log CFU/g with TSP, 0.33 to 3.15 log CFU/g with ASC, 0.82 to 1.97 log CFU/g with CA, and 0.07 to 0.96 log CFU/g with PA. Average reductions were lower (P < 0.001) for gram-positive (0.96 log CFU/g) than for gram-negative (1.33 log CFU/g) bacteria. CA and ASC were the most effective antimicrobial compounds against gram-positive and gram-negative bacteria, respectively. TSP was the second most effective compound for both bacterial groups. Average microbial reductions per gram of skin were 0.87 log CFU/g with TSP, 0.86 log CFU/g with ASC, 1.39 log CFU/g with CA, and 0.74 log CFU/g with PA for gram-positive bacteria, and 1.28 log CFU/g with TSP, 2.03 log CFU/g with ASC, 1.23 log CFU/g with CA, and 0.78 log CFU/g with PA for gram-negative bacteria. With only a few exceptions, microbial reductions in TSP- and ASC-treated samples decreased and those in samples treated with CA increased throughout storage. Samples treated with TSP and samples dipped in CA and ASC had the highest and lowest pH values, respectively, after treatment. The pH of the treated legs tended to return to normal (6.3 to 6.6) during storage. However, at the end of

  7. Bronchointerstitial pneumonia in guinea pigs following inoculation with H5N1 high pathogenicity avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The H5N1 high pathogenicity avian influenza (HPAI) viruses have caused widespread disease of poultry in Asia, Africa and the Middle East, and sporadic human infections. The guinea pig model has been used to study human H3N2 and H1N1 influenza viruses, but knowledge is lacking on H5N1 HPAI virus inf...

  8. Non-coding RNA regulation in pathogenic bacteria located inside eukaryotic cells

    PubMed Central

    Ortega, Álvaro D.; Quereda, Juan J.; Pucciarelli, M. Graciela; García-del Portillo, Francisco

    2014-01-01

    Intracellular bacterial pathogens have evolved distinct lifestyles inside eukaryotic cells. Some pathogens coexist with the infected cell in an obligate intracellular state, whereas others transit between the extracellular and intracellular environment. Adaptation to these intracellular lifestyles is regulated in both space and time. Non-coding small RNAs (sRNAs) are post-transcriptional regulatory molecules that fine-tune important processes in bacterial physiology including cell envelope architecture, intermediate metabolism, bacterial communication, biofilm formation, and virulence. Recent studies have shown production of defined sRNA species by intracellular bacteria located inside eukaryotic cells. The molecules targeted by these sRNAs and their expression dynamics along the intracellular infection cycle remain, however, poorly characterized. Technical difficulties linked to the isolation of “intact” intracellular bacteria from infected host cells might explain why sRNA regulation in these specialized pathogens is still a largely unexplored field. Transition from the extracellular to the intracellular lifestyle provides an ideal scenario in which regulatory sRNAs are intended to participate; so much work must be done in this direction. This review focuses on sRNAs expressed by intracellular bacterial pathogens during the infection of eukaryotic cells, strategies used with these pathogens to identify sRNAs required for virulence, and the experimental technical challenges associated to this type of studies. We also discuss varied techniques for their potential application to study RNA regulation in intracellular bacterial infections. PMID:25429360

  9. Non-coding RNA regulation in pathogenic bacteria located inside eukaryotic cells.

    PubMed

    Ortega, Alvaro D; Quereda, Juan J; Pucciarelli, M Graciela; García-del Portillo, Francisco

    2014-01-01

    Intracellular bacterial pathogens have evolved distinct lifestyles inside eukaryotic cells. Some pathogens coexist with the infected cell in an obligate intracellular state, whereas others transit between the extracellular and intracellular environment. Adaptation to these intracellular lifestyles is regulated in both space and time. Non-coding small RNAs (sRNAs) are post-transcriptional regulatory molecules that fine-tune important processes in bacterial physiology including cell envelope architecture, intermediate metabolism, bacterial communication, biofilm formation, and virulence. Recent studies have shown production of defined sRNA species by intracellular bacteria located inside eukaryotic cells. The molecules targeted by these sRNAs and their expression dynamics along the intracellular infection cycle remain, however, poorly characterized. Technical difficulties linked to the isolation of "intact" intracellular bacteria from infected host cells might explain why sRNA regulation in these specialized pathogens is still a largely unexplored field. Transition from the extracellular to the intracellular lifestyle provides an ideal scenario in which regulatory sRNAs are intended to participate; so much work must be done in this direction. This review focuses on sRNAs expressed by intracellular bacterial pathogens during the infection of eukaryotic cells, strategies used with these pathogens to identify sRNAs required for virulence, and the experimental technical challenges associated to this type of studies. We also discuss varied techniques for their potential application to study RNA regulation in intracellular bacterial infections.

  10. Antimicrobial peptides targeting Gram-negative pathogens, produced and delivered by lactic acid bacteria.

    PubMed

    Volzing, Katherine; Borrero, Juan; Sadowsky, Michael J; Kaznessis, Yiannis N

    2013-11-15

    We present results of tests with recombinant Lactococcus lactis that produce and secrete heterologous antimicrobial peptides with activity against Gram-negative pathogenic Escherichia coli and Salmonella . In an initial screening, the activities of numerous candidate antimicrobial peptides, made by solid state synthesis, were assessed against several indicator pathogenic E. coli and Salmonella strains. Peptides A3APO and Alyteserin were selected as top performers based on high antimicrobial activity against the pathogens tested and on significantly lower antimicrobial activity against L. lactis . Expression cassettes containing the signal peptide of the protein Usp45 fused to the codon-optimized sequence of mature A3APO and Alyteserin were cloned under the control of a nisin-inducible promoter PnisA and transformed into L. lactis IL1403. The resulting recombinant strains were induced to express and secrete both peptides. A3APO- and Alyteserin-containing supernatants from these recombinant L. lactis inhibited the growth of pathogenic E. coli and Salmonella by up to 20-fold, while maintaining the host's viability. This system may serve as a model for the production and delivery of antimicrobial peptides by lactic acid bacteria to target Gram-negative pathogenic bacteria populations.

  11. Electrochemical impedance immunosensor for rapid detection of stressed pathogenic Staphylococcus aureus bacteria.

    PubMed

    Bekir, Karima; Barhoumi, Houcine; Braiek, Mohamed; Chrouda, Amani; Zine, Nadia; Abid, Nabil; Maaref, Abdelrazek; Bakhrouf, Amina; Ouada, Hafedh Ben; Jaffrezic-Renault, Nicole; Mansour, Hedi Ben

    2015-10-01

    In this work, we report the adaptation of bacteria to stress conditions that induce instability of their cultural, morphological, and enzymatic characters, on which the identification of pathogenic bacteria is based. These can raise serious issues during the characterization of bacteria. The timely detection of pathogens is also a subject of great importance. For this reason, our objective is oriented towards developing an immunosensing system for rapid detection and quantification of Staphylococcus aureus. Polyclonal anti-S. aureus are immobilized onto modified gold electrode by self-assembled molecular monolayer (SAM) method. The electrochemical performances of the developed immunosensor were evaluated by impedance spectroscopy through the monitoring of the charge transfer resistance at the modified solid/liquid interface using ferri-/ferrocyanide as redox probe. The developed immunosensor was applied to detect stressed and resuscitate bacteria. As a result, a stable and reproducible immunosensor with sensitivity of 15 kΩ/decade and a detection limit of 10 CFU/mL was obtained for the S. aureus concentrations ranging from 10(1) to 10(7) CFU/mL. A low deviation in the immunosensor response (±10 %) was signed when it is exposed to stressed and not stressed bacteria.

  12. Prevalence of pathogenic bacteria in Ixodes ricinus ticks in Central Bohemia.

    PubMed

    Klubal, Radek; Kopecky, Jan; Nesvorna, Marta; Sparagano, Olivier A E; Thomayerova, Jana; Hubert, Jan

    2016-01-01

    Bacteria associated with the tick Ixodes ricinus were assessed in specimens unattached or attached to the skin of cats, dogs and humans, collected in the Czech Republic. The bacteria were detected by PCR in 97 of 142 pooled samples including 204 ticks, i.e. 1-7 ticks per sample, collected at the same time from one host. A fragment of the bacterial 16S rRNA gene was amplified, cloned and sequenced from 32 randomly selected samples. The most frequent sequences were those related to Candidatus Midichloria midichlori (71% of cloned sequences), followed by Diplorickettsia (13%), Spiroplasma (3%), Rickettsia (3%), Pasteurella (3%), Morganella (3%), Pseudomonas (2%), Bacillus (1%), Methylobacterium (1%) and Phyllobacterium (1%). The phylogenetic analysis of Spiroplasma 16S rRNA gene sequences showed two groups related to Spiroplasma eriocheiris and Spiroplasma melliferum, respectively. Using group-specific primers, the following potentially pathogenic bacteria were detected: Borellia (in 20% of the 142 samples), Rickettsia (12%), Spiroplasma (5%), Diplorickettsia (5%) and Anaplasma (2%). In total, 68% of I. ricinus samples (97/142) contained detectable bacteria and 13% contained two or more putative pathogenic groups. The prevalence of tick-borne bacteria was similar to the observations in other European countries. PMID:26612395

  13. Prevalence of pathogenic bacteria in Ixodes ricinus ticks in Central Bohemia.

    PubMed

    Klubal, Radek; Kopecky, Jan; Nesvorna, Marta; Sparagano, Olivier A E; Thomayerova, Jana; Hubert, Jan

    2016-01-01

    Bacteria associated with the tick Ixodes ricinus were assessed in specimens unattached or attached to the skin of cats, dogs and humans, collected in the Czech Republic. The bacteria were detected by PCR in 97 of 142 pooled samples including 204 ticks, i.e. 1-7 ticks per sample, collected at the same time from one host. A fragment of the bacterial 16S rRNA gene was amplified, cloned and sequenced from 32 randomly selected samples. The most frequent sequences were those related to Candidatus Midichloria midichlori (71% of cloned sequences), followed by Diplorickettsia (13%), Spiroplasma (3%), Rickettsia (3%), Pasteurella (3%), Morganella (3%), Pseudomonas (2%), Bacillus (1%), Methylobacterium (1%) and Phyllobacterium (1%). The phylogenetic analysis of Spiroplasma 16S rRNA gene sequences showed two groups related to Spiroplasma eriocheiris and Spiroplasma melliferum, respectively. Using group-specific primers, the following potentially pathogenic bacteria were detected: Borellia (in 20% of the 142 samples), Rickettsia (12%), Spiroplasma (5%), Diplorickettsia (5%) and Anaplasma (2%). In total, 68% of I. ricinus samples (97/142) contained detectable bacteria and 13% contained two or more putative pathogenic groups. The prevalence of tick-borne bacteria was similar to the observations in other European countries.

  14. New Trends in Impedimetric Biosensors for the Detection of Foodborne Pathogenic Bacteria

    PubMed Central

    Wang, Yixian; Ye, Zunzhong; Ying, Yibin

    2012-01-01

    The development of a rapid, sensitive, specific method for the foodborne pathogenic bacteria detection is of great importance to ensure food safety and security. In recent years impedimetric biosensors which integrate biological recognition technology and impedance have gained widespread application in the field of bacteria detection. This paper presents an overview on the progress and application of impedimetric biosensors for detection of foodborne pathogenic bacteria, particularly the new trends in the past few years, including the new specific bio-recognition elements such as bacteriophage and lectin, the use of nanomaterials and microfluidics techniques. The applications of these new materials or techniques have provided unprecedented opportunities for the development of high-performance impedance bacteria biosensors. The significant developments of impedimetric biosensors for bacteria detection in the last five years have been reviewed according to the classification of with or without specific bio-recognition element. In addition, some microfluidics systems, which were used in the construction of impedimetric biosensors to improve analytical performance, are introduced in this review. PMID:22737018

  15. Simultaneous aptasensor for multiplex pathogenic bacteria detection based on multicolor upconversion nanoparticles labels.

    PubMed

    Wu, Shijia; Duan, Nuo; Shi, Zhao; Fang, Congcong; Wang, Zhouping

    2014-03-18

    A highly sensitive and specific multiplex method for the simultaneous detection of three pathogenic bacteria was fabricated using multicolor upconversion nanoparticles (UCNPs) as luminescence labels coupled with aptamers as the molecular recognition elements. Multicolor UCNPs were synthesized via doping with various rare-earth ions to obtain well-separated emission peaks. The aptamer sequences were selected using the systematic evolution of ligands by exponential enrichment (SELEX) strategy for Staphylococcus aureus, Vibrio parahemolyticus, and Salmonella typhimurium. When applied in this method, aptamers can be used for the specific recognition of the bacteria from complex mixtures, including those found in real food matrixes. Aptamers and multicolor UCNPs were employed to selectively capture and simultaneously quantify the three target bacteria on the basis of the independent peaks. Under optimal conditions, the correlation between the concentration of three bacteria and the luminescence signal was found to be linear from 50-10(6) cfu mL(-1). Improved by the magnetic separation and concentration effect of Fe3O4 magnetic nanoparticles, the limits of detection of the developed method were found to be 25, 10, and 15 cfu mL(-1) for S. aureus, V. parahemolyticus, and S. typhimurium, respectively. The capability of the bioassay in real food samples was also investigated, and the results were consistent with experimental results obtained from plate-counting methods. This proposed method for the detection of various pathogenic bacteria based on multicolor UCNPs has great potential in the application of food safety and multiplex nanosensors. PMID:24568625

  16. Simultaneous aptasensor for multiplex pathogenic bacteria detection based on multicolor upconversion nanoparticles labels.

    PubMed

    Wu, Shijia; Duan, Nuo; Shi, Zhao; Fang, Congcong; Wang, Zhouping

    2014-03-18

    A highly sensitive and specific multiplex method for the simultaneous detection of three pathogenic bacteria was fabricated using multicolor upconversion nanoparticles (UCNPs) as luminescence labels coupled with aptamers as the molecular recognition elements. Multicolor UCNPs were synthesized via doping with various rare-earth ions to obtain well-separated emission peaks. The aptamer sequences were selected using the systematic evolution of ligands by exponential enrichment (SELEX) strategy for Staphylococcus aureus, Vibrio parahemolyticus, and Salmonella typhimurium. When applied in this method, aptamers can be used for the specific recognition of the bacteria from complex mixtures, including those found in real food matrixes. Aptamers and multicolor UCNPs were employed to selectively capture and simultaneously quantify the three target bacteria on the basis of the independent peaks. Under optimal conditions, the correlation between the concentration of three bacteria and the luminescence signal was found to be linear from 50-10(6) cfu mL(-1). Improved by the magnetic separation and concentration effect of Fe3O4 magnetic nanoparticles, the limits of detection of the developed method were found to be 25, 10, and 15 cfu mL(-1) for S. aureus, V. parahemolyticus, and S. typhimurium, respectively. The capability of the bioassay in real food samples was also investigated, and the results were consistent with experimental results obtained from plate-counting methods. This proposed method for the detection of various pathogenic bacteria based on multicolor UCNPs has great potential in the application of food safety and multiplex nanosensors.

  17. New trends in impedimetric biosensors for the detection of foodborne pathogenic bacteria.

    PubMed

    Wang, Yixian; Ye, Zunzhong; Ying, Yibin

    2012-01-01

    The development of a rapid, sensitive, specific method for the foodborne pathogenic bacteria detection is of great importance to ensure food safety and security. In recent years impedimetric biosensors which integrate biological recognition technology and impedance have gained widespread application in the field of bacteria detection. This paper presents an overview on the progress and application of impedimetric biosensors for detection of foodborne pathogenic bacteria, particularly the new trends in the past few years, including the new specific bio-recognition elements such as bacteriophage and lectin, the use of nanomaterials and microfluidics techniques. The applications of these new materials or techniques have provided unprecedented opportunities for the development of high-performance impedance bacteria biosensors. The significant developments of impedimetric biosensors for bacteria detection in the last five years have been reviewed according to the classification of with or without specific bio-recognition element. In addition, some microfluidics systems, which were used in the construction of impedimetric biosensors to improve analytical performance, are introduced in this review.

  18. Microbicidal activity of tripotassium phosphate and fatty acids toward spoilage and pathogenic bacteria associated with poultry.

    PubMed

    Hinton, Arthur; Ingram, Kimberly D

    2005-07-01

    The ability of solutions of tripotassium phosphate (TPP) and fatty acids (lauric and myristic acids) to reduce populations of spoilage and pathogenic microorganisms associated with processed poultry was examined. In vitro studies were conducted with cultures of bacteria (Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, and Staphylococcus aureus) and yeasts (Candida ernobii and Yarrowia lipolytica). Cultures of the bacteria and yeasts were suspended in solutions of TPP or mixtures of TPP with lauric or myristic acid and mixed for 5 min. Viable numbers (log CFU per milliliter) in the suspensions were enumerated on microbiological agar. Results indicated that TPP solutions are highly bactericidal toward gram-negative bacteria and that mixtures of TPP and fatty acids are highly microbicidal toward gram-negative bacteria, gram-positive bacteria, and yeasts. The microbicidal activity of mixtures of TPP and fatty acids toward the native bacterial flora of skin of processed broiler carcasses was also examined. Skin samples were washed in mixtures of TPP and fatty acid, and the populations of total aerobic bacteria, campylobacters, enterococci, E. coli, lactic acid bacteria, pseudomonads, staphylococci, and yeasts in the skin rinsates were enumerated on the appropriate microbiological media. Results indicated that washing the skin in mixtures of TPP and fatty acids produced significant reductions in the number of aerobic bacteria, campylobacters, E. coli, pseudomonads, and yeasts recovered from skin rinsates, but there was no significant reduction in the populations of enterococci, lactic acid bacteria, or staphylococci. These findings indicate that mixtures of TPP and fatty acids possess microbicidal activity against several microorganisms associated with processed poultry and that these solutions could be useful as microbicides to reduce the populations of some bacteria and yeasts associated with some poultry

  19. Antimicrobial activity of different Finnish monofloral honeys against human pathogenic bacteria

    PubMed Central

    Huttunen, Sanna; Riihinen, Kaisu; Kauhanen, Jussi; Tikkanen-Kaukanen, Carina

    2013-01-01

    The antimicrobial activity and phenolic compounds of five Finnish honey products against important human pathogens Streptococcus pneumoniae, S. pyogenes, Staphylococcus aureus, and methicillin-resistant S. aureus were analyzed. Microbroth dilution method and HPLC-DAD were used in antimicrobial testing and phenolic compound determination, respectively. Significant antimicrobial activity (p < 0.01) against all the tested pathogens was found from willow herb (Epilobium angustifolium), heather (Calluna vulgaris), and buckwheat (Fagopyrum esculentum) honeys. This is the first report on antimicrobial activity of Finnish monofloral honeys against streptococcal and staphylococcal bacteria. To our knowledge this is also the first report on the antimicrobial effect of honey against S. pneumoniae. PMID:23278378

  20. Antibacterial peptide nisin: a potential role in the inhibition of oral pathogenic bacteria.

    PubMed

    Tong, Zhongchun; Ni, Longxing; Ling, Junqi

    2014-10-01

    Although the antimicrobial peptide nisin has been extensively studied in the food industry for decades, its application in the oral cavity remains to develop and evaluate its feasibility in treating oral common diseases. Nisin is an odorless, colorless, tasteless substance with low toxicity and with antibacterial activities against Gram-positive bacteria. These biologic properties may establish its use in promising products for oral diseases. This article summarizes the antibacterial efficiency of nisin against pathogenic bacteria related to dental caries and root canal infection and discusses the combination of nisin and common oral drugs.

  1. Antibacterial peptide nisin: a potential role in the inhibition of oral pathogenic bacteria.

    PubMed

    Tong, Zhongchun; Ni, Longxing; Ling, Junqi

    2014-10-01

    Although the antimicrobial peptide nisin has been extensively studied in the food industry for decades, its application in the oral cavity remains to develop and evaluate its feasibility in treating oral common diseases. Nisin is an odorless, colorless, tasteless substance with low toxicity and with antibacterial activities against Gram-positive bacteria. These biologic properties may establish its use in promising products for oral diseases. This article summarizes the antibacterial efficiency of nisin against pathogenic bacteria related to dental caries and root canal infection and discusses the combination of nisin and common oral drugs. PMID:25088158

  2. Effect of applying inoculants with heterolactic or homolactic and heterolactic bacteria on the fermentation and quality of corn silage.

    PubMed

    Arriola, K G; Kim, S C; Adesogan, A T

    2011-03-01

    This study examined the effect of applying different bacterial inoculants on the fermentation and quality of corn silage. Corn plants were harvested at 35% DM, chopped, and ensiled in 20-L mini silos after application of (1) deionized water (CON) or inoculants containing (2) 1 × 10(5) cfu/g of Pediococcus pentosaceus 12455 and Propionibacteria freudenreichii (B2); (3) 4 × 10(5) cfu/g of Lactobacillus buchneri 40788 (BUC); or (4) 1 × 10(5) cfu/g of Pediococcus pentosaceus 12455 and 4 × 10(5) cfu/g of L. buchneri 40788 (B500). Four replicates of each treatment were weighed into polyethylene bags within 20-L mini silos. Silos were stored for 575 d at ambient temperature (25°C) in a covered barn. After silos were opened, aerobic stability, chemical composition, and yeast and mold counts were determined. The DNA in treated and untreated silages was extracted using lysozyme/sodium dodecyl sulfate lysis and phenol/chloroform and used as a template for a conventional PCR with primers designed on the 16S rRNA gene to detect the presence of L. buchneri in all silage samples. Acetic acid concentration was greater in B2 silages versus others (6.46 vs. 4.23% DM). Silages treated with BUC and B500 had lower pH and propionic acid concentration and greater lactic acid concentration than others. The B500 silage had the greatest lactic:acetic acid ratio (1.54 vs. 0.41), and only treatment with BUC reduced DM losses (5.0 vs. 14.3%). Yeast and mold counts were less than the threshold (10(5)) typically associated with silage spoilage and did not differ among treatments. Consequently, all silages were very stable (>250 h). Aerobic stability was not improved by any inoculant but was lower in B500 silages versus others (276 vs. 386 h). The conventional PCR confirmed the presence of similar populations of L. buchneri in all silages. This may have contributed to the prolonged aerobic stability of all silages.

  3. Innate immune response of bovine mammary gland to pathogenic bacteria responsible for mastitis.

    PubMed

    Oviedo-Boyso, Javier; Valdez-Alarcón, Juan J; Cajero-Juárez, Marcos; Ochoa-Zarzosa, Alejandra; López-Meza, Joel E; Bravo-Patiño, Alejandro; Baizabal-Aguirre, Víctor M

    2007-04-01

    Mastitis (mammary gland inflammation) is one of the most important bovine diseases causing economic losses to dairy producers. Mammary gland inflammation is a consequence of the activity of a number of cell and soluble factors that function together to eliminate invading microorganisms. The factors involved in this inflammatory response differ depending on the infectious agent. This review analyzes the factors involved in the immunologic mechanisms against the main pathogenic bacteria causing mastitis, and emphasizes the innate immune response of the mammary gland. Knowledge, at the molecular level, of the mammary gland immune response during infection by pathogenic bacteria is fundamental to the design of effective therapies to control and eradicate bovine mastitis. PMID:16882453

  4. A new pentaplex-nested PCR to detect five pathogenic bacteria in free living amoebae.

    PubMed

    Calvo, L; Gregorio, I; García, A; Fernández, M T; Goñi, P; Clavel, A; Peleato, M L; Fillat, M F

    2013-02-01

    Changes in water use and anthropogenic activity have major impacts on the quality of natural aquatic ecosystems, water distribution and wastewater plants. One of the main problems is the presence of some pathogenic microorganisms that are resistant to disinfection procedures when they are hosted by free living amoeba and that in many cases are hardly detectable by culture-based procedures. In this work we report a sensitive, low-cost procedure consisting of a pentaplex-nested PCR that allows simultaneous detection of Legionella pneumophila, Mycobacterium spp., Pseudomonas spp., Vibrio cholerae and the microcystin-producing cyanobacteria Microcystis aeruginosa. The method has been used to detect the presence of these pathogenic bacteria in water and inside free living amoeba. Its validation in 72 samples obtained from different water sources from Aragon (Spain) evidences that Mycobacterium and Pseudomonas spp are prevailing as amoeba-resistant bacteria.

  5. Rapid and high-throughput detection of highly pathogenic bacteria by Ibis PLEX-ID technology.

    PubMed

    Jacob, Daniela; Sauer, Uschi; Housley, Roberta; Washington, Cicely; Sannes-Lowery, Kristin; Ecker, David J; Sampath, Rangarajan; Grunow, Roland

    2012-01-01

    In this manuscript, we describe the identification of highly pathogenic bacteria using an assay coupling biothreat group-specific PCR with electrospray ionization mass spectrometry (PCR/ESI-MS) run on an Ibis PLEX-ID high-throughput platform. The biothreat cluster assay identifies most of the potential bioterrorism-relevant microorganisms including Bacillus anthracis, Francisella tularensis, Yersinia pestis, Burkholderia mallei and pseudomallei, Brucella species, and Coxiella burnetii. DNA from 45 different reference materials with different formulations and different concentrations were chosen and sent to a service screening laboratory that uses the PCR/ESI-MS platform to provide a microbial identification service. The standard reference materials were produced out of a repository built up in the framework of the EU funded project "Establishment of Quality Assurances for Detection of Highly Pathogenic Bacteria of Potential Bioterrorism Risk" (EQADeBa). All samples were correctly identified at least to the genus level.

  6. Manufacturing a low-cost ceramic water filter and filter system for the elimination of common pathogenic bacteria

    NASA Astrophysics Data System (ADS)

    Simonis, J. J.; Basson, A. K.

    Africa is one of the most water-scarce continents in the world but it is the lack of potable water which results in diarrhoea being the leading cause of death amongst children under the age of five in Africa (696 million children under 5 years old in Africa contract diarrhoea resulting in 2000 deaths per day: WHO and UNICEF, 2009). Most potable water treatment methods use bulk water treatment not suitable or available to the majority of rural poor in Sub-Saharan Africa. One simple but effective way of making sure that water is of good quality is by purifying it by means of a household ceramic water filter. The making and supply of water filters suitable for the removal of suspended solids, pathogenic bacteria and other toxins from drinking water is therefore critical. A micro-porous ceramic water filter with micron-sized pores was developed using the traditional slip casting process. This locally produced filter has the advantage of making use of less raw materials, cost, labour, energy and expertise and being more effective and efficient than other low cost produced filters. The filter is fitted with a silicone tube inserted into a collapsible bag that acts as container and protection for the filter. Enhanced flow is obtained through this filter system. The product was tested using water inoculated with high concentrations of different bacterial cultures as well as with locally polluted stream water. The filter is highly effective (log10 > 4 with 99.99% reduction efficiency) in providing protection from bacteria and suspended solids found in natural water. With correct cleaning and basic maintenance this filter technology can effectively provide drinking water to rural families affected by polluted surface water sources. This is an African solution for the more than 340 million people in Africa without access to clean drinking water (WHO and UNICEF, 2008).

  7. Effect of co-inoculations of native PGPR with nitrogen fixing bacteria on seedling traits in Prosopis cineraria.

    PubMed

    Singh, S K; Pancholy, Anjly; Jindal, S K; Pathak, Rakesh

    2014-09-01

    Prosopis cineraria significantly contribute to sand dune stabilization, soil fertility rejuvenation and is an integral component of agro-forestry systems in arid regions of India. Effect of different rhizobacterial seed treatments on seed germination and seedling traits in two genotypes of P. cineraria (HPY-1) and (FG-1) were tested. Observations on seed germination (%) and seedling traits viz., root length (cm), shoot length (cm), seedling weight (g) and seedling length of different treatments were recorded. Whereas, germination index (GI), seedling vigour index (SVI) and root/shoot length ratio were derived from the observed data. The scarification treatment with sulphuric acid for 10 minutes substantially enhanced germination from < 20% to 80-82% in control treatments. Treatments with co-inoculations of Bacillus licheniformis and Sinorhizobium kostiense or S. saheli supported the maximum seed germination and seedling growth and vigour. The maximum germination per cent (92.5%), seedling length (10.94 cm), seedling vigour index (10.12) and germination index (7.97) were recorded with treatment (V2T6) wherein seeds of high pod yielding genotype were co-inoculated with Bacillus licheniformis and S. kostiense. The higher positive correlations of seedling length v/s shoot length followed by SVI v/s seedling length, SVI v/s root length and seedling length v/s root length is a fair indicative of inter dependency of these characteristics. Higher R2 values of root length v/s shoot length followed by that of SVI v/s GI indicates that a regression line fits the data well and future outcomes of observed seedling traits are likely to be predicted by the model.

  8. The Mutualistic Side of Wolbachia-Isopod Interactions: Wolbachia Mediated Protection Against Pathogenic Intracellular Bacteria.

    PubMed

    Braquart-Varnier, Christine; Altinli, Mine; Pigeault, Romain; Chevalier, Frédéric D; Grève, Pierre; Bouchon, Didier; Sicard, Mathieu

    2015-01-01

    Wolbachia is a vertically transmitted endosymbiont whose radiative success is mainly related to various host reproductive manipulations that led to consider this symbiont as a conflictual reproductive parasite. However, lately, some Wolbachia have been shown to act as beneficial symbionts by protecting hosts against a broad range of parasites. Still, this protection has been mostly demonstrated in artificial Wolbachia-host associations between partners that did not co-evolved together. Here, we tested in two terrestrial isopod species Armadillidium vulgare and Porcellio dilatatus whether resident Wolbachia (native or non-native) could confer protection during infections with Listeria ivanovii and Salmonella typhimurium and also during a transinfection with a Wolbachia strain that kills the recipient host (i.e., wVulC in P. dilatatus). Survival analyses showed that (i) A. vulgare lines hosting their native Wolbachia (wVulC) always exhibited higher survival than asymbiotic ones when infected with pathogenic bacteria (ii) P. dilatatus lines hosting their native wDil Wolbachia strain survived the S. typhimurium infection better, while lines hosting non-native wCon Wolbachia strain survived the L. ivanovii and also the transinfection with wVulC from A. vulgare better. By studying L. ivanovii and S. typhimurium loads in the hemolymph of the different host-Wolbachia systems, we showed that (i) the difference in survival between lines after L. ivanovii infections were not linked to the difference between their pathogenic bacterial loads, and (ii) the difference in survival after S. typhimurium infections corresponds to lower loads of pathogenic bacteria. Overall, our results demonstrate a beneficial effect of Wolbachia on survival of terrestrial isopods when infected with pathogenic intracellular bacteria. This protective effect may rely on different mechanisms depending on the resident symbiont and the invasive bacteria interacting together within the hosts. PMID:26733946

  9. The Mutualistic Side of Wolbachia–Isopod Interactions: Wolbachia Mediated Protection Against Pathogenic Intracellular Bacteria

    PubMed Central

    Braquart-Varnier, Christine; Altinli, Mine; Pigeault, Romain; Chevalier, Frédéric D.; Grève, Pierre; Bouchon, Didier; Sicard, Mathieu

    2015-01-01

    Wolbachia is a vertically transmitted endosymbiont whose radiative success is mainly related to various host reproductive manipulations that led to consider this symbiont as a conflictual reproductive parasite. However, lately, some Wolbachia have been shown to act as beneficial symbionts by protecting hosts against a broad range of parasites. Still, this protection has been mostly demonstrated in artificial Wolbachia-host associations between partners that did not co-evolved together. Here, we tested in two terrestrial isopod species Armadillidium vulgare and Porcellio dilatatus whether resident Wolbachia (native or non-native) could confer protection during infections with Listeria ivanovii and Salmonella typhimurium and also during a transinfection with a Wolbachia strain that kills the recipient host (i.e., wVulC in P. dilatatus). Survival analyses showed that (i) A. vulgare lines hosting their native Wolbachia (wVulC) always exhibited higher survival than asymbiotic ones when infected with pathogenic bacteria (ii) P. dilatatus lines hosting their native wDil Wolbachia strain survived the S. typhimurium infection better, while lines hosting non-native wCon Wolbachia strain survived the L. ivanovii and also the transinfection with wVulC from A. vulgare better. By studying L. ivanovii and S. typhimurium loads in the hemolymph of the different host-Wolbachia systems, we showed that (i) the difference in survival between lines after L. ivanovii infections were not linked to the difference between their pathogenic bacterial loads, and (ii) the difference in survival after S. typhimurium infections corresponds to lower loads of pathogenic bacteria. Overall, our results demonstrate a beneficial effect of Wolbachia on survival of terrestrial isopods when infected with pathogenic intracellular bacteria. This protective effect may rely on different mechanisms depending on the resident symbiont and the invasive bacteria interacting together within the hosts. PMID:26733946

  10. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. To improve the control of this disease it’s necessary to better understand the pathog...

  11. Rapid detection of pathogenic bacteria by volatile organic compound (VOC) analysis

    NASA Astrophysics Data System (ADS)

    Senecal, Andre G.; Magnone, Joshua; Yeomans, Walter; Powers, Edmund M.

    2002-02-01

    Developments in rapid detection technologies have made countless improvements over the years. However, because of the limited sample that these technologies can process in a single run, the chance of capturing and identifying a small amount of pathogens is difficult. The problem is further magnified by the natural random distribution of pathogens in foods. Methods to simplify pathogenic detection through the identification of bacteria specific VOC were studied. E. coli O157:H7 and Salmonella typhimurium were grown on selected agar medium to model protein, and carbohydrate based foods. Pathogenic and common spoilage bacteria (Pseudomonas and Morexella) were screened for unique VOC production. Bacteria were grown on agar slants in closed vials. Headspace sampling was performed at intervals up to 24 hours using Solid Phase Micro-Extraction (SPME) techniques followed by GC/MS analysis. Development of unique volatiles was followed to establish sensitivity of detection. E. coli produced VOC not found in either Trypticase Soy Yeast (TSY) agar blanks or spoilage organism samples were - indole, 1-decanol, and 2-nonanone. Salmonella specific VOC grown on TSY were 3-methyl-1-butanol, dimethyl sulfide, 2-undecanol, 2-pentadecanol and 1-octanol. Trials on potato dextrose agar (PDA) slants indicated VOC specific for E. coli and Salmonella when compared to PDA blanks and Pseudomonas samples. However, these VOC peaks were similar for both pathogens. Morexella did not grow on PDA slants. Work will continue with model growth mediums at various temperatures, and mixed flora inoculums. As well as, VOC production based on the dynamics of bacterial growth.

  12. Long-term social dynamics drive loss of function in pathogenic bacteria

    PubMed Central

    Andersen, Sandra Breum; Marvig, Rasmus Lykke; Molin, Søren; Krogh Johansen, Helle; Griffin, Ashleigh S.

    2015-01-01

    Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly sophisticated methods for monitoring phenotypic and genotypic dynamics in bacteria causing infectious disease, but in contrast, we lack evidence-based adaptive explanations for those changes. Evolutionary change during infection is often interpreted as host adaptation, but this assumption neglects to consider social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find that Pseudomonas aeruginosa bacteria, causing lung infections in patients with cystic fibrosis, lose cooperative iron acquisition by siderophore production during infection. This loss could be caused by changes in iron availability in the lung, but surprisingly, we find that cells retain the ability to take up siderophores produced by conspecifics, even after they have lost the ability to synthesize siderophores. Only when cooperative producers are lost from the population is the receptor for uptake lost. This finding highlights the potential pitfalls of interpreting loss of function in pathogenic bacterial populations as evidence for trait redundancy in the host environment. More generally, we provide an example of how sequence analysis can be used to generate testable hypotheses about selection driving long-term phenotypic changes of pathogenic bacteria in situ. PMID:26240352

  13. Novel antibiotics targeting respiratory ATP synthesis in Gram-positive pathogenic bacteria.

    PubMed

    Balemans, Wendy; Vranckx, Luc; Lounis, Nacer; Pop, Ovidiu; Guillemont, Jérôme; Vergauwen, Karen; Mol, Selena; Gilissen, Ron; Motte, Magali; Lançois, David; De Bolle, Miguel; Bonroy, Kristien; Lill, Holger; Andries, Koen; Bald, Dirk; Koul, Anil

    2012-08-01

    Emergence of drug-resistant bacteria represents a high, unmet medical need, and discovery of new antibacterials acting on new bacterial targets is strongly needed. ATP synthase has been validated as an antibacterial target in Mycobacterium tuberculosis, where its activity can be specifically blocked by the diarylquinoline TMC207. However, potency of TMC207 is restricted to mycobacteria with little or no effect on the growth of other Gram-positive or Gram-negative bacteria. Here, we identify diarylquinolines with activity against key Gram-positive pathogens, significantly extending the antibacterial spectrum of the diarylquinoline class of drugs. These compounds inhibited growth of Staphylococcus aureus in planktonic state as well as in metabolically resting bacteria grown in a biofilm culture. Furthermore, time-kill experiments showed that the selected hits are rapidly bactericidal. Drug-resistant mutations were mapped to the ATP synthase enzyme, and biochemical analysis as well as drug-target interaction studies reveal ATP synthase as a target for these compounds. Moreover, knockdown of the ATP synthase expression strongly suppressed growth of S. aureus, revealing a crucial role of this target in bacterial growth and metabolism. Our data represent a proof of principle for using the diarylquinoline class of antibacterials in key Gram-positive pathogens. Our results suggest that broadening the antibacterial spectrum for this chemical class is possible without drifting off from the target. Development of the diarylquinolines class may represent a promising strategy for combating Gram-positive pathogens. PMID:22615276

  14. Elucidation of bacteria found in car interiors and strategies to reduce the presence of potential pathogens.

    PubMed

    Stephenson, Rachel E; Gutierrez, Daniel; Peters, Cindy; Nichols, Mark; Boles, Blaise R

    2014-01-01

    The human microbiome is influenced by a number of factors, including environmental exposure to microbes. Because many humans spend a large amount of time in built environments, it can be expected that the microbial ecology of these environments will influence the human microbiome. In an attempt to further understand the microbial ecology of built environments, the microbiota of car interiors was analyzed using culture dependent and culture independent methods. While it was found that the number and type of bacteria varied widely among the cars and sites tested, Staphylococcus and Propionibacterium were nearly always the dominant genera found at the locations sampled. Because Staphylococcus is of particular concern to human health, the characteristics of this genus found in car interiors were investigated. Staphylococcus epidermidis, S. aureus, and S. warnerii were the most prevalent staphylococcal species found, and 22.6% of S. aureus strains isolated from shared community vehicles were resistant to methicillin. The reduction in the prevalence of pathogenic bacteria in cars by using silver-based antimicrobial surface coatings was also evaluated. Coatings containing 5% silver ion additives were applied to steering wheels, placed in cars for five months and were found to eliminate the presence of culturable pathogenic bacteria recovered from these sites relative to controls. Together, these results provide new insight into the microbiota found in an important built environment, the automobile, and potential strategies for controlling the presence of human pathogens.

  15. Elucidation of bacteria found in car interiors and strategies to reduce the presence of potential pathogens

    PubMed Central

    Stephenson, Rachel E.; Gutierrez, Daniel; Peters, Cindy; Nichols, Mark; Boles, Blaise R.

    2014-01-01

    The human microbiome is influenced by a number of factors, including environmental exposure to microbes. Because many humans spend a large amount of time in built environments, it can be expected that the microbial ecology of these environments will influence the human microbiome. In an attempt to further understand the microbial ecology of built environments, the microbiota of car interiors was analyzed using culture dependent and culture independent methods. While it was found that the number and type of bacteria varied widely among the cars and sites tested, Staphylococcus and Propionibacterium were nearly always the dominant genera found at the locations sampled. Because Staphylococcus is of particular concern to human health, the characteristics of this genus found in car interiors were investigated. Staphylococcus epidermidis, S. aureus, and S. warnerii were the most prevalent staphylococcal species found, and 22.6% of S. aureus strains isolated from shared community vehicles were resistant to methicillin. The reduction in the prevalence of pathogenic bacteria in cars by using silver-based antimicrobial surface coatings was also evaluated. Coatings containing 5% silver ion additives were applied to steering wheels, placed in cars for five months and were found to eliminate the presence of culturable pathogenic bacteria recovered from these sites relative to controls. Together, these results provide new insight into the microbiota found in an important built environment, the automobile, and potential strategies for controlling the presence of human pathogens. PMID:24564823

  16. Fluorescence in situ hybridization rapidly detects three different pathogenic bacteria in urinary tract infection samples.

    PubMed

    Wu, Qing; Li, Yan; Wang, Ming; Pan, Xiao P; Tang, Yong F

    2010-11-01

    The detection of pathogenic bacteria in urine is an important criterion for diagnosing urinary tract infections (UTIs). By using fluorescence in situ hybridization (FISH) with rRNA-targeted, fluorescently labeled oligonucleotide probes, bacterial pathogens present in urine samples were identified within 3-4 h. In this study, three probes that are specific for Escherichia coli, Enterococcus faecalis and Staphylococcus aureus were designed based on the conserved 16S RNA sequences, whereas probe Eub338 broadly recognizes all bacteria. We collected a total of 1000 urine samples, and 325 of these samples tested positive for a UTI via traditional culturing techniques; additionally, all 325 of these samples tested positive with the Eub338 probe in FISH analysis. FISH analyses with species-specific probes were performed in parallel to the test the ability to differentiate among several pathogenic bacteria. The samples for these experiments included 76 E. coli infected samples, 32 E. faecalis infected samples and 9 S. aureus infected samples. Compared to conventional methods of bacterial identification, the FISH method produced positive results for >90% of the samples tested. FISH has the potential to become an extremely useful diagnostic tool for UTIs because it has a quick turnaround time and high accuracy.

  17. In-situ detection of multiple pathogenic bacteria on food surfaces

    NASA Astrophysics Data System (ADS)

    Chai, Yating; Horikawa, Shin; Hu, Jiajia; Chen, I.-Hsuan; Hu, Jing; Barbaree, James M.; Chin, Bryan A.

    2015-05-01

    Real-time in-situ detection of pathogenic bacteria on fresh food surfaces was accomplished with phage-based magnetoelastic (ME) biosensors. The ME biosensor is constructed of a small rectangular strip of ME material that is coated with a biomolecular recognition element (phage, antibodies or proteins, etc.) that is specific to the target pathogen. This mass-sensitive ME biosensor is wirelessly actuated into mechanical resonance by an externally applied time-varying magnetic field. When the biosensor binds with target bacteria, the mass of the sensor increases, resulting in a decrease in the sensor's resonant frequency. In order to compensate for nonspecific binding, control biosensors without phage were used in this experiment. In previous research, the biosensors were measured one by one. However, the simultaneous measurement of multiple sensors was accomplished in this research, and promises to greatly shorten the analysis time for bacterial detection. Additionally, the use of multiple biosensors enables the possibility of simultaneous detection of different pathogenic bacteria. This paper presents results of experiments in which multiple phage-based ME biosensors were simultaneously monitored. The E2 phage and JRB7 phage from a landscape phage library served as the bio-recognition element that have the capability of binding specifically with Salmonella typhimurium and B. anthracis spores, respectively. Real-time in-situ detection of Salmonella typhimurium and B. anthracis spores on food surfaces are presented.

  18. Long-term social dynamics drive loss of function in pathogenic bacteria.

    PubMed

    Andersen, Sandra Breum; Marvig, Rasmus Lykke; Molin, Søren; Krogh Johansen, Helle; Griffin, Ashleigh S

    2015-08-25

    Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly sophisticated methods for monitoring phenotypic and genotypic dynamics in bacteria causing infectious disease, but in contrast, we lack evidence-based adaptive explanations for those changes. Evolutionary change during infection is often interpreted as host adaptation, but this assumption neglects to consider social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find that Pseudomonas aeruginosa bacteria, causing lung infections in patients with cystic fibrosis, lose cooperative iron acquisition by siderophore production during infection. This loss could be caused by changes in iron availability in the lung, but surprisingly, we find that cells retain the ability to take up siderophores produced by conspecifics, even after they have lost the ability to synthesize siderophores. Only when cooperative producers are lost from the population is the receptor for uptake lost. This finding highlights the potential pitfalls of interpreting loss of function in pathogenic bacterial populations as evidence for trait redundancy in the host environment. More generally, we provide an example of how sequence analysis can be used to generate testable hypotheses about selection driving long-term phenotypic changes of pathogenic bacteria in situ. PMID:26240352

  19. The Use of Colorimetric Sensor Arrays to Discriminate between Pathogenic Bacteria

    PubMed Central

    Lonsdale, Claire L.; Taba, Brian; Queralto, Nuria; Lukaszewski, Roman A.; Martino, Raymond A.; Rhodes, Paul A.; Lim, Sung H.

    2013-01-01

    A colorimetric sensor array is a high-dimensional chemical sensor that is cheap, compact, disposable, robust, and easy to operate, making it a good candidate technology to detect pathogenic bacteria, especially potential bioterrorism agents like Yersinia pestis and Bacillus anthracis which feature on the Center for Disease Control and Prevention’s list of potential biothreats. Here, a colorimetric sensor array was used to continuously monitor the volatile metabolites released by bacteria in solid media culture in an Advisory Committee on Dangerous Pathogen Containment Level 3 laboratory. At inoculum concentrations as low as 8 colony-forming units per plate, 4 different bacterial species were identified with 100% accuracy using logistic regression to classify the kinetic profile of sensor responses to culture headspace gas. The sensor array was able to further discriminate between different strains of the same species, including 5 strains of Yersinia pestis and Bacillus anthracis. These preliminary results suggest that disposable colorimetric sensor arrays can be an effective, low-cost tool to identify pathogenic bacteria. PMID:23671629

  20. Potential human pathogenic bacteria in a mixed urban watershed as revealed by pyrosequencing.

    PubMed

    Ibekwe, A Mark; Leddy, Menu; Murinda, Shelton E

    2013-01-01

    Current microbial source tracking (MST) methods for water depend on testing for fecal indicator bacterial counts or specific marker gene sequences to identify fecal contamination where potential human pathogenic bacteria could be present. In this study, we applied 454 high-throughput pyrosequencing to identify bacterial pathogen DNA sequences, including those not traditionally monitored by MST and correlated their abundances to specific sources of contamination such as urban runoff and agricultural runoff from concentrated animal feeding operations (CAFOs), recreation park area, waste-water treatment plants, and natural sites with little or no human activities. Samples for pyrosequencing were surface water, and sediment collected from 19 sites. A total of 12,959 16S rRNA gene sequences with average length of ≤400 bp were obtained, and were assigned to corresponding taxonomic ranks using ribosomal database project (RDP), Classifier and Greengenes databases. The percent of total potential pathogens were highest in urban runoff water (7.94%), agricultural runoff sediment (6.52%), and Prado Park sediment (6.00%), respectively. Although the numbers of DNA sequence tags from pyrosequencing were very high for the natural site, corresponding percent potential pathogens were very low (3.78-4.08%). Most of the potential pathogenic bacterial sequences identified were from three major phyla, namely, Proteobacteria, Bacteroidetes, and Firmicutes. The use of deep sequencing may provide improved and faster methods for the identification of pathogen sources in most watersheds so that better risk assessment methods may be developed to enhance public health.

  1. Neighborhood diversity of potentially pathogenic bacteria in drinking water from the city of Maroua, Cameroon.

    PubMed

    Healy-Profitós, Jessica; Lee, Seungjun; Mouhaman, Arabi; Garabed, Rebecca; Moritz, Mark; Piperata, Barbara; Lee, Jiyoung

    2016-06-01

    This study examined the spatial variation of potential gastrointestinal pathogens within drinking water sources and home storage containers in four neighborhoods in Maroua, Cameroon. Samples were collected from source (n = 28) and home containers (n = 60) in each study neighborhood. Pathogen contamination was assessed using quantitative polymerase chain reaction, targeting Campylobacter spp., Shiga toxin producing Escherichia coli (virulence genes, stx1 and stx2), and Salmonella spp. Microbial source tracking (MST) targeted three different host-specific markers: HF183 (human), Rum2Bac (ruminant) and GFD (poultry) to identify contamination sources. Staphylococcus aureus and the tetracycline-resistance gene (tetQ) were assessed to measure human hand contact and presence of antibiotic-resistant bacteria. Pathogen/MST levels were compared statistically and spatially, and neighborhood variation was compared with previously collected demographic information. All the test fecal markers and pathogens (except Arcobacter) were detected in home and source samples. Two neighborhoods tested positive for most pathogens/MST while the others only tested positive for one or two. Spatial variation of pathogens/MST existed between sources, storage containers, and neighborhoods. Differing population density and ethno-economic characteristics could potentially explain variation. Future research should explore the influence of demographic and ethno-economic factors on water quality during microbial risk assessments in urban Africa. PMID:27280618

  2. Neighborhood diversity of potentially pathogenic bacteria in drinking water from the city of Maroua, Cameroon.

    PubMed

    Healy-Profitós, Jessica; Lee, Seungjun; Mouhaman, Arabi; Garabed, Rebecca; Moritz, Mark; Piperata, Barbara; Lee, Jiyoung

    2016-06-01

    This study examined the spatial variation of potential gastrointestinal pathogens within drinking water sources and home storage containers in four neighborhoods in Maroua, Cameroon. Samples were collected from source (n = 28) and home containers (n = 60) in each study neighborhood. Pathogen contamination was assessed using quantitative polymerase chain reaction, targeting Campylobacter spp., Shiga toxin producing Escherichia coli (virulence genes, stx1 and stx2), and Salmonella spp. Microbial source tracking (MST) targeted three different host-specific markers: HF183 (human), Rum2Bac (ruminant) and GFD (poultry) to identify contamination sources. Staphylococcus aureus and the tetracycline-resistance gene (tetQ) were assessed to measure human hand contact and presence of antibiotic-resistant bacteria. Pathogen/MST levels were compared statistically and spatially, and neighborhood variation was compared with previously collected demographic information. All the test fecal markers and pathogens (except Arcobacter) were detected in home and source samples. Two neighborhoods tested positive for most pathogens/MST while the others only tested positive for one or two. Spatial variation of pathogens/MST existed between sources, storage containers, and neighborhoods. Differing population density and ethno-economic characteristics could potentially explain variation. Future research should explore the influence of demographic and ethno-economic factors on water quality during microbial risk assessments in urban Africa.

  3. Microbiologic characteristics of pathogenic bacteria from hospitalized trauma patients who survived Wenchuan earthquake.

    PubMed

    Zhang, B; Liu, Z; Lin, Z; Zhang, X; Fu, W

    2012-10-01

    The purpose of this study is to investigate the microbiological characterization of pathogenic bacteria isolated from trauma patients after Wenchuan earthquake in 2008. Most infections were identified in the patients over 60 years of age, with an incidence rate of 78.5%, and more infections in wound (43.3%) and respiratory tract (37.1%) sites were identified. A total of 97 non-duplicated clinical pathogens were isolated from 91 trauma patients. Of those pathogens, 62 (63.9%) were Gram-negative bacilli, 23 (23.7%) were Gram-positive cocci, 9 (9.3%) were fungi, and 3 (3.1%) were anaerobes, such as Clostridium perfringens. The distribution spectrum of pathogens isolated from trauma patients after earthquake was different to that from non-earthquake trauma patients in our hospital at the same time. The most prevalent pathogenic isolates were Escherichia coli (15.4%), Acinetobacter baumannii (14.4%), Staphylococcus aureus (12.3%), Burkholderia cepacia (11.3%), and Enterococcus spp. (9.3%). The drug susceptibility results showed that most of the Gram-negative bacilli, except for Pseudomonas aeruginosa and Burkholderia cepacia, were susceptible to imipenem, but resistant to the first- and the second-generation cephalosporins. Most of the Gram-positive cocci were susceptible to vancomycin, linezolid, and Synercid/dalfopristin. Characteristics of pathogenic bacterium isolated from trauma patients after earthquake have been demonstrated which play an important role in the appropriate treatment of infections. PMID:22910807

  4. Application of bacteriophages in post-harvest control of human pathogenic and food spoiling bacteria.

    PubMed

    Pérez Pulido, Rubén; Grande Burgos, Maria José; Gálvez, Antonio; Lucas López, Rosario

    2016-10-01

    Bacteriophages have attracted great attention for application in food biopreservation. Lytic bacteriophages specific for human pathogenic bacteria can be isolated from natural sources such as animal feces or industrial wastes where the target bacteria inhabit. Lytic bacteriophages have been tested in different food systems for inactivation of main food-borne pathogens including Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Salmonella enterica, Shigella spp., Campylobacter jejuni and Cronobacter sakazkii, and also for control of spoilage bacteria. Application of lytic bacteriophages could selectively control host populations of concern without interfering with the remaining food microbiota. Bacteriophages could also be applied for inactivation of bacteria attached to food contact surfaces or grown as biofilms. Bacteriophages may receive a generally recognized as safe status based on their lack of toxicity and other detrimental effects to human health. Phage preparations specific for L. monocytogenes, E. coli O157:H7 and S. enterica serotypes have been commercialized and approved for application in foods or as part of surface decontamination protocols. Phage endolysins have a broader host specificity compared to lytic bacteriophages. Cloned endolysins could be used as natural preservatives, singly or in combination with other antimicrobials such as bacteriocins.

  5. Ultrarapid Detection of Pathogenic Bacteria Using a 3D Immunomagnetic Flow Assay

    PubMed Central

    Lee, Wonjae; Kwon, Donghoon; Chung, Boram; Jung, Gyoo Yeol; Au, Anthony; Folch, Albert; Jeon, Sangmin

    2015-01-01

    We developed a novel 3D immunomagnetic flow assay for the rapid detection of pathogenic bacteria in a large-volume food sample. Antibody-functionalized magnetic nanoparticle clusters (AbMNCs) were magnetically immobilized on the surfaces of a 3D-printed cylindrical microchannel. The injection of a Salmonella-spiked sample solution into the microchannel produced instant binding between the AbMNCs and the Salmonella bacteria due to their efficient collisions. Nearly perfect capture of the AbMNCs and AbMNCs-Salmonella complexes was achieved under a high flow rate by stacking permanent magnets with spacers inside the cylindrical separator to maximize the magnetic force. The concentration of the bacteria in solution was determined using ATP luminescence measurements. The detection limit was better than 10 cfu/mL, and the overall assay time, including the binding, rinsing, and detection steps for a 10 mL sample took less than 3 min. To our knowledge, the 3D immunomagnetic flow assay described here provides the fastest high-sensitivity, high-capacity method for the detection of pathogenic bacteria. PMID:24856003

  6. Ultrarapid detection of pathogenic bacteria using a 3D immunomagnetic flow assay.

    PubMed

    Lee, Wonjae; Kwon, Donghoon; Chung, Boram; Jung, Gyoo Yeol; Au, Anthony; Folch, Albert; Jeon, Sangmin

    2014-07-01

    We developed a novel 3D immunomagnetic flow assay for the rapid detection of pathogenic bacteria in a large-volume food sample. Antibody-functionalized magnetic nanoparticle clusters (AbMNCs) were magnetically immobilized on the surfaces of a 3D-printed cylindrical microchannel. The injection of a Salmonella-spiked sample solution into the microchannel produced instant binding between the AbMNCs and the Salmonella bacteria due to their efficient collisions. Nearly perfect capture of the AbMNCs and AbMNCs-Salmonella complexes was achieved under a high flow rate by stacking permanent magnets with spacers inside the cylindrical separator to maximize the magnetic force. The concentration of the bacteria in solution was determined using ATP luminescence measurements. The detection limit was better than 10 cfu/mL, and the overall assay time, including the binding, rinsing, and detection steps for a 10 mL sample took less than 3 min. To our knowledge, the 3D immunomagnetic flow assay described here provides the fastest high-sensitivity, high-capacity method for the detection of pathogenic bacteria.

  7. Antagonistic control of microbial pathogens under iron limitations by siderophore producing bacteria in a chemostat setup.

    PubMed

    Fgaier, Hedia; Eberl, Hermann J

    2011-03-21

    Certain bacteria develop iron chelation mechanisms that allow them to scavenge dissolved iron from the environment and to make it unavailable to competitors. This is achieved by producing siderophores that bind the iron which is later liberated internally in the cell. Under conditions of iron limitation, siderophore producing bacteria have therefore an antagonistic growth advantage over other species. This has been observed in particular in agricultural and aquacultural systems, as well as in food microbiology. We investigate here the possibility of a probiotic biocontrol strategy to eradicate a well established, often pathogenic, non-chelating population by supplementing the system with generally regarded as safe siderophore producing bacteria. Set in a chemostat setup, our modeling and simulation studies suggest that this is indeed possible in a finite time treatment. PMID:21192949

  8. Treatment of gaseous toluene in three biofilters inoculated with fungi/bacteria: Microbial analysis, performance and starvation response.

    PubMed

    Cheng, Zhuowei; Lu, Lichao; Kennes, Christian; Yu, Jianming; Chen, Jianmeng

    2016-02-13

    Bacteria and fungi are often utilized for the biodegradation of organic pollutants. This study compared fungal and/or bacterial biofiltration in treating toluene under both steady and unsteady states. Fungal biofilter (F-BF) removed less toluene than both bacterial biofilters (B-BF) and fungal & bacterial biofilters (F&B-BF) (<20% vs >60% vs >90%). The mineralization ratio was also lower in F-BF-levels were 2/3 and 1/2 of those values obtained by the other biofilters. Microbial analysis showed that richer communities were present in B-BF and F&B-BF, and that the Hypocreales genus which Trichoderma viride belongs to was much better represented in F&B-BF. The F&B-BF also supported enhanced robustness after 15-day starvation episodes; 1 day later the performance recovered to 80% of the original removal level. The combination of bacteria and fungi makes biofiltration a good option for VOC treatment including better removal and performance stability versus individual biofilters (bacteria or fungi dominated). PMID:26513567

  9. Treatment of gaseous toluene in three biofilters inoculated with fungi/bacteria: Microbial analysis, performance and starvation response.

    PubMed

    Cheng, Zhuowei; Lu, Lichao; Kennes, Christian; Yu, Jianming; Chen, Jianmeng

    2016-02-13

    Bacteria and fungi are often utilized for the biodegradation of organic pollutants. This study compared fungal and/or bacterial biofiltration in treating toluene under both steady and unsteady states. Fungal biofilter (F-BF) removed less toluene than both bacterial biofilters (B-BF) and fungal & bacterial biofilters (F&B-BF) (<20% vs >60% vs >90%). The mineralization ratio was also lower in F-BF-levels were 2/3 and 1/2 of those values obtained by the other biofilters. Microbial analysis showed that richer communities were present in B-BF and F&B-BF, and that the Hypocreales genus which Trichoderma viride belongs to was much better represented in F&B-BF. The F&B-BF also supported enhanced robustness after 15-day starvation episodes; 1 day later the performance recovered to 80% of the original removal level. The combination of bacteria and fungi makes biofiltration a good option for VOC treatment including better removal and performance stability versus individual biofilters (bacteria or fungi dominated).

  10. Effect of poultry decontaminants concentration on growth kinetics for pathogenic and spoilage bacteria.

    PubMed

    del Río, Elena; González de Caso, Beatriz; Prieto, Miguel; Alonso-Calleja, Carlos; Capita, Rosa

    2008-10-01

    Various chemical compounds are currently under review for final approval as poultry decontaminants in the European Union (EU). Concentration is among the factors considered by the EU authorities in the evaluation of these treatments. The aim of this research was to compare the growth parameters for pathogenic and spoilage bacteria in presence of high and low concentrations of poultry decontaminants to assess whether such treatments could involve a potential sanitary risk for consumers. Growth curves for Salmonella enterica serotype Enteritidis, Listeria monocytogenes, Pseudomonas fluorescens and Brochothrix thermosphacta were obtained at different levels of trisodium phosphate (TSP; 1.74%; 0.58%), acidified sodium chlorite (ASC; 210 ppm; 70 ppm) and citric acid (CA; 0.27%; 0.09%). The modified Gompertz equation was used as primary model to fit observed data. ASC and TSP were the most effective compounds in increasing lag phase (L) and reducing maximum growth rate (mu) in Gram-negative bacteria. Gram-positive bacteria were more influenced by CA. At high TSP levels, mu for Salmonella decreased. Low TSP levels increased mu for Salmonella and Listeria relative to control samples. In presence of 0.27% CA, Brochothrix showed the highest L and the lowest mu among strains tested. These results suggest that low TSP and high CA concentrations could favour the outgrowth of pathogenic bacteria (e.g. Salmonella) relative to spoilage bacteria, rending these treatments potentially dangerous for consumers. The findings of this study may be useful to the EU authorities and meat processors in their efforts to select adequate treatments for control of bacteria on poultry. PMID:18721678

  11. [Selective detection of viable pathogenic bacteria in water using reverse transcription quantitative PCR].

    PubMed

    Lin, Yi-Wen; Li, Dan; Wu, Shu-Xu; He, Miao; Yang, Tian

    2012-11-01

    A reverse transcription q quantitative PCR (RT-qPCR) assay method was established, which can quantify the copy numbers of RNA in pathogenic bacteria of E. coli and Enterococcus faecium. The results showed that cDNA was generated with the RT-PCR reagents, target gene was quantified with the qPCR, the copy numbers of RNA were stable at about 1 copies x CFU(-1) for E. coli and 7.98 x 10(2) copies x CFU(-1) for Enterococcus faecium respectively during the stationary grow phase for the both indicator bacteria [E. coli (6-18 h) and Enterococcus faecium (10-38 h)]. The established RT-qPCR method can quantify the numbers of viable bacteria through detecting bacterial RNA targets. Through detecting the heat-treated E. coli and Enterococcus faecium by three methods (culture method, qPCR, RT-qPCR), we found that the qPCR and RT-qPCR can distinguish 1.43 lg copy non-viable E. coli and 2.5 lg copy non-viable Enterococcus faecium. These results indicated that the established methods could effectively distinguish viable bacteria from non-viable bacteria. Finally we used this method to evaluate the real effluents of the secondary sedimentation of wastewater treatment plant (WWTP), the results showed that the correlation coefficients (R2) between RT-qPCR and culture method were 0.930 (E. coli) and 0.948 (Enterococcus faecium), and this established RT-PCR method can rapidly detect viable pathogenic bacteria in genuine waters.

  12. Fluorescence in situ hybridization investigation of potentially pathogenic bacteria involved in neonatal porcine diarrhea

    PubMed Central

    2014-01-01

    Background Neonatal diarrhea is a multifactorial condition commonly present on pig farms and leads to economic losses due to increased morbidity and mortality of piglets. Immature immune system and lack of fully established microbiota at birth predispose neonatal piglets to infection with enteric pathogens. The microorganisms that for decades have been associated with enteritis and diarrhea in suckling piglets are: rotavirus A, coronavirus, enterotoxigenic Escherichia coli (ETEC), Clostridium perfringens type C, Cryptosporidium spp., Giardia spp., Cystoisospora suis and Strongyloides ransomi. However, in recent years, the pig industry has experienced an increased number of neonatal diarrhea cases in which the above mentioned pathogens are no longer detected. Potentially pathogenic bacteria have recently received focus in the research on the possible etiology of neonatal diarrhea not caused by common pathogens. The primary aim of this study was to investigate the role of E. coli, Enterococcus spp., C. perfringens and C. difficile in the pathogenesis of neonatal porcine diarrhea with no established casual agents. Fluorescence in situ hybridization with oligonucleotide probes was applied on the fixed intestinal tissue samples from 51 diarrheic and 50 non-diarrheic piglets collected from four Danish farms during outbreaks of neonatal diarrhea not caused by well-known enteric pathogens. Furthermore, an association between the presence of these bacteria and histological lesions was evaluated. Results The prevalence of fluorescence signals specific for E. coli, C. perfringens and C. difficile was similar in both groups of piglets. However, Enterococcus spp. was primarily detected in the diarrheic piglets. Furthermore, adherent bacteria were detected in 37 % diarrheic and 14 % non-diarrheic piglets. These bacteria were identified as E. coli and Enterococcus spp. and their presence in the intestinal mucosa was associated with histopathological changes. Conclusions The

  13. Quorum sensing signal molecules (acylated homoserine lactones) in gram-negative fish pathogenic bacteria.

    PubMed

    Bruhn, Jesper B; Dalsgaard, Inger; Nielsen, Kristian F; Buchholtz, Christiane; Larsen, Jens L; Gram, Lone

    2005-06-14

    The aim of the present study was to investigate the production of quorum sensing signals (specifically acylated homoserine lactones, AHLs) among a selection of strains of Gram-negative fish bacterial pathogens. These signals are involved in the regulation of virulence factors in some human and plant-pathogenic bacteria. A total of 59 strains, representing 9 different fish pathogenic species, were tested against 2 AHL monitor bacteria (Agrobacterium tumefaciens NT1 [pZLR4] and Chromobacterium violaceum CV026) in a well diffusion assay and by thin-layer chromatography (TLC). Representative samples were further characterized by high performance liquid chromatography-high resolution mass spectrometry (HPLC-HR-MS). AHLs were produced by all strains of Aeromonas salmonicida, Aeromonas hydrophila, Yersinia ruckeri, Vibrio salmonicida, and Vibrio vulnificus. Some strains of atypical Aeromonas salmonicida and Vibrio splendidus were also positive. Aeromonas species produced N-butanoyl homoserine lactone (BHL) and N-hexanoyl homoserine lactone (HHL) and 1 additional product, whereas N-3-oxo-hexanoyl homoserine lactone (OHHL) and HHL were detected in Vibrio salmonicida. N-3-oxo-octanoyl homoserine lactone (OOHL) and N-3-octanoyl homoserine lactone (OHL) were detected in Y. ruckeri. AHLs were not detected from strains of Photobacterium damselae, Flavobacterium psychrophilum or Moritella viscosa. AHLs were extracted from fish infected with Y. ruckeri but not from fish infected with A. salmonicida. In conclusion, the production of quorum sensing signals, AHLs, is common among the strains that we examined. If the AHL molecules regulate the expression of the virulence phenotype in these bacteria, as shown to occur in some bacterial pathogens, novel disease control measures may be developed by blocking AHL-mediated communication and suppressing virulence.

  14. Outer-Inner Membrane Vesicles Naturally Secreted by Gram-Negative Pathogenic Bacteria

    PubMed Central

    Pérez-Cruz, Carla; Delgado, Lidia; López-Iglesias, Carmen; Mercade, Elena

    2015-01-01

    Outer-inner membrane vesicles (O-IMVs) were recently described as a new type of membrane vesicle secreted by the Antarctic bacterium Shewanella vesiculosa M7T. Their formation is characterized by the protrusion of both outer and plasma membranes, which pulls cytoplasmic components into the vesicles. To demonstrate that this is not a singular phenomenon in a bacterium occurring in an extreme environment, the identification of O-IMVs in pathogenic bacteria was undertaken. With this aim, a structural study by Transmission Electron Microscopy (TEM) and Cryo-transmission electron microscopy (Cryo-TEM) was carried out, confirming that O-IMVs are also secreted by Gram-negative pathogenic bacteria such as Neisseria gonorrhoeae, Pseudomonas aeruginosa PAO1 and Acinetobacter baumannii AB41, in which they represent between 0.23% and 1.2% of total vesicles produced. DNA and ATP, which are components solely found in the cell cytoplasm, were identified within membrane vesicles of these strains. The presence of DNA inside the O-IMVs produced by N. gonorrhoeae was confirmed by gold DNA immunolabeling with a specific monoclonal IgM against double-stranded DNA. A proteomic analysis of N. gonorrhoeae-derived membrane vesicles identified proteins from the cytoplasm and plasma membrane. This confirmation of O-IMV extends the hitherto uniform definition of membrane vesicles in Gram-negative bacteria and explains the presence of components in membrane vesicles such as DNA, cytoplasmic and inner membrane proteins, as well as ATP, detected for the first time. The production of these O-IMVs by pathogenic Gram-negative bacteria opens up new areas of study related to their involvement in lateral gene transfer, the transfer of cytoplasmic proteins, as well as the functionality and role of ATP detected in these new vesicles. PMID:25581302

  15. Virulence and pathogenicity of Candida albicans is enhanced in biofilms containing oral bacteria.

    PubMed

    Cavalcanti, Yuri Wanderley; Morse, Daniel James; da Silva, Wander José; Del-Bel-Cury, Altair Antoninha; Wei, Xiaoqing; Wilson, Melanie; Milward, Paul; Lewis, Michael; Bradshaw, David; Williams, David Wynne

    2015-01-01

    This study examined the influence of bacteria on the virulence and pathogenicity of candidal biofilms. Mature biofilms (Candida albicans-only, bacteria-only, C. albicans with bacteria) were generated on acrylic and either analysed directly, or used to infect a reconstituted human oral epithelium (RHOE). Analyses included Candida hyphae enumeration and assessment of Candida virulence gene expression. Lactate dehydrogenase (LDH) activity and Candida tissue invasion following biofilm infection of the RHOE were also measured. Candida hyphae were more prevalent (p < 0.05) in acrylic biofilms also containing bacteria, with genes encoding secreted aspartyl-proteinases (SAP4/SAP6) and hyphal-wall protein (HWP1) up-regulated (p < 0.05). Candida adhesin genes (ALS3/EPA1), SAP6 and HWP1 were up-regulated in mixed-species biofilm infections of RHOE. Multi-species infections exhibited higher hyphal proportions (p < 0.05), up-regulation of IL-18, higher LDH activity and tissue invasion. As the presence of bacteria in acrylic biofilms promoted Candida virulence, consideration should be given to the bacterial component when managing denture biofilm associated candidoses.

  16. Autonomously Sensing Hydrogels for the Rapid and Selective Detection of Pathogenic Bacteria.

    PubMed

    Ebrahimi, Mir-Morteza Sadat; Laabei, Maisem; Jenkins, A Tobias A; Schönherr, Holger

    2015-12-01

    The development of a versatile approach for the rapid and sensitive detection of relevant pathogenic bacteria and autonomous signaling of the detection events in reporter hydrogel film coatings is reported. Exploiting chitosan hydrogel films equipped with chromogenic or fluorogenic reporter moieties, the presence of the Gram-negative bacterium Pseudomonas aeruginosa and the Gram-positive bacterium Staphylococcus aureus is sensed within 1 h by detecting the characteristic enzymes α-glucosidase and elastase with limits of detection (LOD) <45 × 10(-9) M and <20 × 10(-9) M, respectively, for this observation time. The values for the LOD are two to three orders of magnitude smaller than the concentrations of the enzymes detected in the corresponding bacterial supernatants. The results show that the covalently conjugated reporter moieties are exclusively and efficiently reacted by the associated enzyme, allowing in principle for discrimination among different types of bacteria. Since high enzyme concentrations are a result of proliferating bacteria, e.g., in wounds or food, and since the selectivity of the reporting function is easily adapted to bacteria of choice, these reporter hydrogels comprise an interesting platform for the rapid detection of bacteria.

  17. Behaviour of pathogenic and indicator bacteria during urban wastewater treatment and sludge composting, as revealed by quantitative PCR.

    PubMed

    Wéry, Nathalie; Lhoutellier, Claire; Ducray, Florence; Delgenès, Jean-Philippe; Godon, Jean-Jacques

    2008-01-01

    Two enteric pathogens, Salmonella spp. and Campylobacter jejuni, and two bacteria commonly used as indicators, Escherichia coli and Clostridium perfringens, were monitored using quantitative real-time PCR during municipal wastewater treatment and sludge composting. The results were compared with those obtained using standard culture methods. A reduction of all bacteria was observed during wastewater treatment and during the thermophilic phase of composting. However, the bacterial groups studied behaved differently during the process, and the main differences were observed during biological treatment in activated sludge basins. In particular, Salmonella spp. and C. jejuni survived better during activated sludge treatment than E. coli. C. jejuni was the most resistant to wastewater treatment among the four bacterial groups. Overall, differences in survival were observed for all bacteria studied, when submitted to the same environmental pressure. This holds both for differences between indicators and pathogenic bacteria and between pathogenic bacteria. These results show the difficulty in defining reliable indicators.

  18. Method for detection of a few pathogenic bacteria and determination of live versus dead cells

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    This paper presents a method for detection of a few pathogenic bacteria and determination of live versus dead cells. The method combines wireless phage-coated magnetoelastic (ME) biosensors and a surface-scanning dectector, enabling real-time monitoring of the growth of specific bacteria in a nutrient broth. The ME biosensor used in this investigation is composed of a strip-shaped ME resonator upon which an engineered bacteriophage is coated to capture a pathogen of interest. E2 phage with high binding affinity for Salmonella Typhimurium was used as a model study. The specificity of E2 phage has been reported to be 1 in 105 background bacteria. The phage-coated ME biosensors were first exposed to a low-concentration Salmonella suspension to capture roughly 300 cells on the sensor surface. When the growth of Salmonella in the broth occurs, the mass of the biosensor increases, which results in a decrease in the biosensor's resonant frequency. Monitoring of this mass- induced resonant frequency change allows for real-time detection of the presence of Salmonella. Detection of a few bacteria is also possible by growing them to a sufficient number. The surface-scanning detector was used to measure resonant frequency changes of 25 biosensors sequentially in an automated manner as a function of time. This methodology offers direct, real-time detection, quantification, and viability determination of specific bacteria. The rate of the sensor's resonant frequency change was found to be largely dependent on the number of initially bound cells and the efficiency of cell growth.

  19. Structure, Biology, and Therapeutic Application of Toxin–Antitoxin Systems in Pathogenic Bacteria

    PubMed Central

    Lee, Ki-Young; Lee, Bong-Jin

    2016-01-01

    Bacterial toxin–antitoxin (TA) systems have received increasing attention for their diverse identities, structures, and functional implications in cell cycle arrest and survival against environmental stresses such as nutrient deficiency, antibiotic treatments, and immune system attacks. In this review, we describe the biological functions and the auto-regulatory mechanisms of six different types of TA systems, among which the type II TA system has been most extensively studied. The functions of type II toxins include mRNA/tRNA cleavage, gyrase/ribosome poison, and protein phosphorylation, which can be neutralized by their cognate antitoxins. We mainly explore the similar but divergent structures of type II TA proteins from 12 important pathogenic bacteria, including various aspects of protein–protein interactions. Accumulating knowledge about the structure–function correlation of TA systems from pathogenic bacteria has facilitated a novel strategy to develop antibiotic drugs that target specific pathogens. These molecules could increase the intrinsic activity of the toxin by artificially interfering with the intermolecular network of the TA systems. PMID:27782085

  20. Label-free detection of pathogenic bacteria via immobilized antimicrobial peptides.

    PubMed

    Dong, Zong-Mu; Zhao, Guang-Chao

    2015-05-01

    A novel label-free strategy for the detection of bacteria was developed by using a specific antimicrobial peptide (AMP)-functionalized quartz crystal microbalance (QCM) electrode. This electrode interface was successfully applied to detect pathogenic Escherichia coli O157:H7 based on the specific affinity between the small synthetic antimicrobial peptide and the bacterial cell of pathogenic E. coli O157:H7. The concentrations of pathogenic E. coli O157:H7 were sensitively measured by the frequency response of the QCM with a detection limit of 0.4 cfu μL(-1). The detection can be fulfilled within 10 min because it does not require germiculture process. On the other hand, if the specific antimicrobial peptides were immobilized on a gold electrode, this label-free strategy can also be performed by electrochemical impedance spectroscopy (EIS). Compared with QCM technique, the EIS measurement gives a lower sensitivity and needs a longer assay time. The combination of antimicrobial peptides with the real-time responses of QCM, as well as electronic read-out monitoring of EIS, may open a new way for the direct detection of bacteria.

  1. Isolation and quantification of cadmium removal mechanisms in batch reactors inoculated by sulphate reducing bacteria: biosorption versus bioprecipitation.

    PubMed

    Pagnanelli, Francesca; Cruz Viggi, Carolina; Toro, Luigi

    2010-05-01

    Biosorbing properties of sulphate reducing bacteria were tested to distinguish the amount of cadmium removed by bioprecipitation from that bound onto biomass surface (biosorption). Experimental results of cadmium abatement in batch growth tests (bioprecipitation tests) were then compared with metabolism-independent binding properties of SRB cell wall surface (biosorption tests performed with dead biomass). Experimental results showed that SRB inoculum removed 59 + or - 5% of sulphates in 21 days even in presence of cadmium (0-36 mmol L(-1)), while non-monotonous kinetic effects were observed for increasing Cd concentrations. Comparison between bioprecipitation and biosorption tests denoted a significant contribution of biosorption (77%) in total Cd removal (0.40 + or - 0.01 mmol g(-1)). Characterisation of bacterial acid-base surface properties by potentiometric titrations and mechanistic modelling denoted that carboxylic, phosphate and amino groups of cell wall are the main responsible of metal removal by biosorption mechanism.

  2. Shedding and serologic responses following primary and secondary inoculation of house sparrows (Passer domesticus) and European starlings (Sturnus vulgaris) with low-pathogenicity avian influenza virus.

    PubMed

    Nemeth, Nicole M; Thomas, Nicholas O; Orahood, Darcy S; Anderson, Theodore D; Oesterle, Paul T

    2010-10-01

    Waterfowl and shorebirds are well-recognized natural reservoirs of low-pathogenicity avian influenza viruses (LPAIV); however, little is known about the role of passerines in avian influenza virus ecology. Passerines are abundant, widespread, and commonly come into contact with free-ranging birds as well as captive game birds and poultry. We inoculated and subsequently challenged house sparrows (Passer domesticus) and European starlings (Sturnus vulgaris) with wild-bird origin LPAIV H3N8 to evaluate their potential role in transmission. Oropharyngeal shedding was short lived, and was detected in more starlings (97.2%) than sparrows (47.2%; n=36 of each). Cloacal shedding was rare in both species (8.3%; n=36 of each) and no cage-mate transmission occurred. Infectious LPAIV was cultured from oropharyngeal and cloacal swabs and gastrointestinal and respiratory tissues from both species. Seroconversion was detected as early as 3 days post inoculation (d.p.i.) (16.7% of sparrows and 0% of starlings; n=6 each); 50% of these individuals seroconverted by 5 d.p.i., and nearly all birds (97%; n=35) seroconverted by 28 d.p.i. In general, pre-existing homologous immunity led to reduced shedding and increased antibody levels within 7 days of challenge. Limited shedding and lack of cage-mate transmission suggest that passerines are not significant reservoirs of LPAIV, although species differences apparently exist. Passerines readily and consistently seroconverted to LPAIV, and therefore inclusion of passerines in epidemiological studies of influenza outbreaks in wildlife and domestic animals may provide further insight into the potential involvement of passerines in avian influenza virus transmission ecology. PMID:20954019

  3. Antagonistic Characteristics Against Food-borne Pathogenic Bacteria of Lactic Acid Bacteria and Bifidobacteria Isolated from Feces of Healthy Thai Infants

    PubMed Central

    Uraipan, Supansa; Hongpattarakere, Tipparat

    2015-01-01

    Background: Food-borne pathogens are among the most significant problems in maintaining the health of people. Many probiotics have been widely reported to alleviate and protect against gastrointestinal infections through antibacterial secretion. However, the majority of them cannot always play antagonistic roles under gut conditions. Probiotic bacteria of human origin must possess other protective mechanisms to survive, out-compete intestinal flora and to successfully establish in their new host at a significant level. Objectives: Probiotic characteristics of Lactic Acid Bacteria (LAB) and bifidobacteria isolated from the feces of Thai infants were primarily investigated in terms of gastric acid and bile resistances, antibacterial activity and mucin adhesion ability. Antagonistic interaction through secretion of antibacterial compounds and competitive exclusion against food-borne pathogens were also evaluated. Materials and Methods: Culturable LAB and bifidobacteria were isolated from feces of Thai infants. Their ability to withstand gastric acid and bile were then evaluated. Acid and bile salt tolerant LAB and bifidobacteria were identified. They were then further assessed according to their antagonistic interactions through antibacterial secretion, mucin adhesion and competitive mucin adhesion against various food-borne pathogenic bacteria. Results: Gastric acid and bile tolerant LAB and bifidobacteria isolated from healthy infant feces were identified and selected according to their antagonistic interaction against various food-borne pathogenic bacteria. These antagonistic probiotics included four strains of Lactobacillus rhamnosus, two strains of L. casei, five strains of L. plantarum, two strains of Bifidobacterium longum subsp. longum and three strains of B. bifidum. All strains of the selected LAB inhibited all pathogenic bacteria tested through antibacterial secretion, while bifidobacteria showed high level of competitive exclusion against the pathogenic

  4. Estimation of decay rates for fecal indicator bacteria and bacterial pathogens in agricultural field-applied manure

    EPA Science Inventory

    Field-applied manure is an important source of pathogenic exposure in surface water bodies for humans and ecological receptors. We analyzed the persistence and decay of fecal indicator bacteria and bacterial pathogens from three sources (cattle, poultry, swine) for agricultural f...

  5. Exploration of Simple Analytical Approaches for Rapid Detection of Pathogenic Bacteria

    SciTech Connect

    Rahman, Salma

    2005-01-01

    Many of the current methods for pathogenic bacterial detection require long sample-preparation and analysis time, as well as complex instrumentation. This dissertation explores simple analytical approaches (e.g., flow cytometry and diffuse reflectance spectroscopy) that may be applied towards ideal requirements of a microbial detection system, through method and instrumentation development, and by the creation and characterization of immunosensing platforms. This dissertation is organized into six sections. In the general Introduction section a literature review on several of the key aspects of this work is presented. First, different approaches for detection of pathogenic bacteria will be reviewed, with a comparison of the relative strengths and weaknesses of each approach, A general overview regarding diffuse reflectance spectroscopy is then presented. Next, the structure and function of self-assembled monolayers (SAMs) formed from organosulfur molecules at gold and micrometer and sub-micrometer patterning of biomolecules using SAMs will be discussed. This section is followed by four research chapters, presented as separate manuscripts. Chapter 1 describes the efforts and challenges towards the creation of imunosensing platforms that exploit the flexibility and structural stability of SAMs of thiols at gold. 1H, 1H, 2H, 2H-perfluorodecyl-1-thiol SAM (PFDT) and dithio-bis(succinimidyl propionate)-(DSP)-derived SAMs were used to construct the platform. Chapter 2 describes the characterization of the PFDT- and DSP-derived SAMs, and the architectures formed when it is coupled to antibodies as well as target bacteria. These studies used infrared reflection spectroscopy (IRS), X-ray photoelectron spectroscopy (XPS), and electrochemical quartz crystal microbalance (EQCM), Chapter 3 presents a new sensitive, and portable diffuse reflection based technique for the rapid identification and quantification of pathogenic bacteria. Chapter 4 reports research efforts in the

  6. Potential Human Pathogenic Bacteria in a Mixed Urban Watershed as Revealed by Pyrosequencing

    PubMed Central

    Ibekwe, A. Mark; Leddy, Menu; Murinda, Shelton E.

    2013-01-01

    Current microbial source tracking (MST) methods for water depend on testing for fecal indicator bacterial counts or specific marker gene sequences to identify fecal contamination where potential human pathogenic bacteria could be present. In this study, we applied 454 high-throughput pyrosequencing to identify bacterial pathogen DNA sequences, including those not traditionally monitored by MST and correlated their abundances to specific sources of contamination such as urban runoff and agricultural runoff from concentrated animal feeding operations (CAFOs), recreation park area, waste-water treatment plants, and natural sites with little or no human activities. Samples for pyrosequencing were surface water, and sediment collected from 19 sites. A total of 12,959 16S rRNA gene sequences with average length of ≤400 bp were obtained, and were assigned to corresponding taxonomic ranks using ribosomal database project (RDP), Classifier and Greengenes databases. The percent of total potential pathogens were highest in urban runoff water (7.94%), agricultural runoff sediment (6.52%), and Prado Park sediment (6.00%), respectively. Although the numbers of DNA sequence tags from pyrosequencing were very high for the natural site, corresponding percent potential pathogens were very low (3.78–4.08%). Most of the potential pathogenic bacterial sequences identified were from three major phyla, namely, Proteobacteria, Bacteroidetes, and Firmicutes. The use of deep sequencing may provide improved and faster methods for the identification of pathogen sources in most watersheds so that better risk assessment methods may be developed to enhance public health. PMID:24278139

  7. [Detection of pathogenic bacteria Rhizobium vitis in vineyards of the south of Ukraine].

    PubMed

    Korotaieva N V; Limanska N V

    2015-01-01

    The total number of microbiota from grape crown gall tissues ranged from (2,3 ± 0.8) x 10(3) to (7.3 ± 0.4) x 10(5) CFU/g. The amount of bacteria from Rhizobium genus reached from (1.2 ±0.2) x 10(2) to (2.1 ± 0.2) x 10(4) CFU/g depending on a tested plant. It was found out that only a small percentage of the strains (3.1 - 4.9%) were oncogenic. New pathogenic strains (R. vitis ONU388, R. vitis ONU389 and R. vitis ONU390) possessing plasmid genes of pathogenicity virC, ipt and virD2 were isolated. PMID:26036030

  8. Gluconacetobacter diazotrophicus Elicits a Sugarcane Defense Response Against a Pathogenic Bacteria Xanthomonas albilineans

    PubMed Central

    Vinagre, Fabiano; Estevez, Yandi; Bernal, Aydiloide; Perez, Juana; Cavalcanti, Janaina; Santana, Ignacio; Hemerly, Adriana S

    2006-01-01

    A new role for the plant growth-promoting nitrogen-fixing endophytic bacteria Gluconacetobacter diazotrophicus has been identified and characterized while it is involved in the sugarcane-Xanthomonas albilineans pathogenic interactions. Living G.diazotrophicus possess and/or produce elicitor molecules which activate the sugarcane defense response resulting in the plant resistance to X. albilineans, in this particular case controlling the pathogen transmission to emerging agamic shoots. A total of 47 differentially expressed transcript derived fragments (TDFs) were identified by cDNA-AFLP. Transcripts showed significant homologies to genes of the ethylene signaling pathway (26%), proteins regulates by auxins (9%), β-1,3 Glucanase proteins (6%) and ubiquitin genes (4%), all major signaling mechanisms. Results point toward a form of induction of systemic resistance in sugarcane-G. diazotrophicus interactions which protect the plant against X. albilineans attack. PMID:19516988

  9. Detection and Characterization of Cancer Cells and Pathogenic Bacteria Using Aptamer-Based Nano-Conjugates

    PubMed Central

    Gedi, Vinayakumar; Kim, Young-Pil

    2014-01-01

    Detection and characterization of cells using aptamers and aptamer-conjugated nanoprobes has evolved a great deal over the past few decades. This evolution has been driven by the easy selection of aptamers via in vitro cell-SELEX, permitting sensitive discrimination between target and normal cells, which includes pathogenic prokaryotic and cancerous eukaryotic cells. Additionally, when the aptamer-based strategies are used in conjunction with nanomaterials, there is the potential for cell targeting and therapeutic effects with improved specificity and sensitivity. Here we review recent advances in aptamer-based nano-conjugates and their applications for detecting cancer cells and pathogenic bacteria. The multidisciplinary research utilized in this field will play an increasingly significant role in clinical medicine and drug discovery. PMID:25268922

  10. [Detection of pathogenic bacteria Rhizobium vitis in vineyards of the south of Ukraine].

    PubMed

    Korotaieva N V; Limanska N V

    2015-01-01

    The total number of microbiota from grape crown gall tissues ranged from (2,3 ± 0.8) x 10(3) to (7.3 ± 0.4) x 10(5) CFU/g. The amount of bacteria from Rhizobium genus reached from (1.2 ±0.2) x 10(2) to (2.1 ± 0.2) x 10(4) CFU/g depending on a tested plant. It was found out that only a small percentage of the strains (3.1 - 4.9%) were oncogenic. New pathogenic strains (R. vitis ONU388, R. vitis ONU389 and R. vitis ONU390) possessing plasmid genes of pathogenicity virC, ipt and virD2 were isolated.

  11. Antimicrobial activity of essential oil of Eucalyptus globulus against fish pathogenic bacteria.

    PubMed

    Park, Joon-Woo; Wendt, Mitchell; Heo, Gang-Joon

    2016-06-01

    The antibacterial activities of the essential oil of Eucalyptus globulus (EOEG) was determined against 7 fish pathogenic bacteria (Edwardsiella tarda, Streptococcus iniae, S. parauberis, Lactococcus garviae, Vibrio harveyi, V. ichthyoenteri and Photobacterium damselae) obtained from farmed olive flounder. The inhibitory activity was evaluated by three methods: Disc diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). According to the disc diffusion test, as the concentration of EOEG (5-40 µg) rises, the inhibitory zone increases in size. Compared with amoxicillin, tetracycline and chloramphenicol, EOEG showed similar antibacterial activity. The MIC of EOEG ranged from 7.8 to 125 mg/mL and MBC values ranged from 62 to 250 mg/mL. These results show that EOEG has antimicrobial activity against all seven bacteria, but there was no marked difference between each genus. From these results, it is suggested that EOEG can be used as an antimicrobial agent against fish bacterial diseases in the fish industry.

  12. Antibacterial properties and major bioactive components of cinnamon stick (Cinnamomum burmannii): activity against foodborne pathogenic bacteria.

    PubMed

    Shan, Bin; Cai, Yi-Zhong; Brooks, John D; Corke, Harold

    2007-07-11

    Cinnamomum burmannii Blume (cinnamon stick) from Indonesia is a little-investigated spice. In this study, the antibacterial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of cinnamon stick extract were evaluated against five common foodborne pathogenic bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella anatum). Cinnamon stick extract exhibited significant antibacterial properties. Major compounds in cinnamon stick were tentatively identified by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC-MS) as a predominant volatile oil component ((E)-cinnamaldehyde) and several polyphenols (mainly proanthocyanidins and (epi)catechins). Both (E)-cinnamaldehyde and proanthocyanidins significantly contributed to the antibacterial properties. Additionally, scanning electron microscopy was used to observe morphological changes of bacteria treated with the crude extract of cinnamon stick and its major components. This study suggests that cinnamon stick and its bioactive components have potential for application as natural food preservatives.

  13. Characterization of pathogenic bacteria by automated headspace concentration-gas chromatography.

    PubMed

    Zechman, J M; Aldinger, S; Labows, J N

    1986-04-25

    Automated headspace concentration-gas chromatography (AHC-GC) was used to profile the volatile metabolites produced by Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Bacterial cultures were incubated in trypticase soy broth and examined at 24 h. The profiles were consistent for each genus examined and variation observed among the different strains of each species was chiefly quantitative. The volatiles were identified by concurrent headspace concentration-gas chromatography-mass spectrometry and consisted mainly of isobutanol, isopentanol, isopentyl acetate, 1-undecene and methyl ketones. There were sufficient differences in the profiles in the 4-6 min elution period to distinguish P. aeruginosa and S. aureus from each other and from the other two bacteria. P. mirabilis and K. pneumoniae typically showed three intense peaks which corresponded to isobutanol, isopentyl acetate and isopentanol. The determination of volatiles by AHC-GC is sensitive, rapid and offers a possible alternative for automatic detection and characterization of pathogenic bacteria. PMID:3086354

  14. The Antibacterial Activity of Chitosan Products Blended with Monoterpenes and Their Biofilms against Plant Pathogenic Bacteria.

    PubMed

    Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M; El-Nouby, Mahmoud A M

    2016-01-01

    This study focuses on the biological activities of eleven chitosan products with a viscosity-average molecular weight ranging from 22 to 846 kDa in combination with the most active monoterpenes (geraniol and thymol), out of 10 tested, against four plant pathogenic bacteria, Agrobacterium tumefaciens, Erwinia carotovora, Corynebacterium fascians, and Pseudomonas solanacearum. The antibacterial activity was evaluated in vitro by the agar dilution technique as a minimum inhibitory concentration (MIC) that was found to be dependent on the type of the microorganism tested. The most active product of chitosan was used for biofilm production enriched with geraniol and thymol (0.1 and 0.5%) and the films were also evaluated against the tested bacteria. The biological bioactivities summarized here may provide novel insights into the functions of chitosan and some monoterpenes and potentially allow their use for food protection from microbial attack. PMID:27127676

  15. The Antibacterial Activity of Chitosan Products Blended with Monoterpenes and Their Biofilms against Plant Pathogenic Bacteria

    PubMed Central

    Badawy, Mohamed E. I.; Rabea, Entsar I.; Taktak, Nehad E. M.; El-Nouby, Mahmoud A. M.

    2016-01-01

    This study focuses on the biological activities of eleven chitosan products with a viscosity-average molecular weight ranging from 22 to 846 kDa in combination with the most active monoterpenes (geraniol and thymol), out of 10 tested, against four plant pathogenic bacteria, Agrobacterium tumefaciens, Erwinia carotovora, Corynebacterium fascians, and Pseudomonas solanacearum. The antibacterial activity was evaluated in vitro by the agar dilution technique as a minimum inhibitory concentration (MIC) that was found to be dependent on the type of the microorganism tested. The most active product of chitosan was used for biofilm production enriched with geraniol and thymol (0.1 and 0.5%) and the films were also evaluated against the tested bacteria. The biological bioactivities summarized here may provide novel insights into the functions of chitosan and some monoterpenes and potentially allow their use for food protection from microbial attack. PMID:27127676

  16. Inhibition of food-borne bacterial pathogens by bacteriocins from lactic acid bacteria isolated from meat.

    PubMed Central

    Lewus, C B; Kaiser, A; Montville, T J

    1991-01-01

    Ten strains of bacteriocin-producing lactic acid bacteria were isolated from retail cuts of meat. These 10 strains along with 11 other bacteriocin-producing lactic acid bacteria were tested for inhibitory activity against psychotrophic pathogens, including four strains of Listeria monocytogenes, two strains of Aeromonas hydrophila, and two strains of Staphylococcus aureus. Inhibition due to acid, hydrogen peroxide, and lytic bacteriophage were excluded. The proteinaceous nature of the inhibitory substance was confirmed by demonstration of its sensitivity to proteolytic enzymes. Eight of the meat isolates had inhibitory activity against all four L. monocytogenes strains. Bacteriocin activity against L. monocytogenes was found in all of the strains obtained from other sources. Activity against A. hydrophila and S. aureus was also common. Images PMID:1908209

  17. When Ribonucleases Come into Play in Pathogens: A Survey of Gram-Positive Bacteria

    PubMed Central

    Jester, Brian C.; Romby, Pascale; Lioliou, Efthimia

    2012-01-01

    It is widely acknowledged that RNA stability plays critical roles in bacterial adaptation and survival in different environments like those encountered when bacteria infect a host. Bacterial ribonucleases acting alone or in concert with regulatory RNAs or RNA binding proteins are the mediators of the regulatory outcome on RNA stability. We will give a current update of what is known about ribonucleases in the model Gram-positive organism Bacillus subtilis and will describe their established roles in virulence in several Gram-positive pathogenic bacteria that are imposing major health concerns worldwide. Implications on bacterial evolution through stabilization/transfer of genetic material (phage or plasmid DNA) as a result of ribonucleases' functions will be covered. The role of ribonucleases in emergence of antibiotic resistance and new concepts in drug design will additionally be discussed. PMID:22550495

  18. Rapid and Selective Detection of Pathogenic Bacteria in Bloodstream Infections with Aptamer-Based Recognition.

    PubMed

    Shen, Haijing; Wang, Jie; Liu, Haoyang; Li, Zhihao; Jiang, Fenglei; Wang, Fu-Bing; Yuan, Quan

    2016-08-01

    Sepsis and bacteremia are life-threatening clinical syndromes associated with significant patient morbidity and mortality. Rapid and sensitive detection of pathogenic bacteria is the key to improve patient survival rates. Herein, we have rationally constructed a simple aptamer-based capture platform to shorten the time needed for confirmation of bacterial bloodstream infection in clinical blood samples. This capture platform is made of a mesoporous TiO2-coated magnetic nanoparticle and is modified with target aptamer. It features excellent bacterial enrichment efficiency of about 80% even at low bacterial concentrations (10-2000 CFU mL(-1)). More importantly, the bacteria can be enriched within 2 h, and the time for bacterial identification is effectively shortened in comparison to the "gold standard" in clinical diagnosis of bloodstream infection. The aptamer-based capture platform may pave a way for the detection of biomarkers and find potential applications in disease diagnosis. PMID:27411775

  19. Functional nanoparticle-based proteomic strategies for characterization of pathogenic bacteria.

    PubMed

    Chen, Wei-Jen; Tsai, Pei-Jane; Chen, Yu-Chie

    2008-12-15

    Although matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) can be employed to rapidly characterize pathogenic bacteria, bacterial cultures are generally required to obtain sufficient quantities of the bacterial cells prior to MALDI MS analysis. If this time-consuming step could be eliminated, the length of time required for identification of bacterial strains would be greatly reduced. In this paper, we propose an effective means of rapidly identifying bacteria--one that does not require bacterial culturing--using functional nanoparticle-based proteomic strategies that are characterized by extremely short analysis time. In this approach, we used titania-coated magnetic iron oxide nanoparticles (Fe(3)O(4)@TiO(2) NPs) as affinity probes to concentrate the target bacteria. The magnetic properties of the Fe(3)O(4)@TiO(2) NPs allow the conjugated target species to be rapidly isolated from the sample solutions under a magnetic field. Taking advantage of the absorption of the magnetic Fe(3)O(4) NPs in the microwave region of the electromagnetic spectrum, we performed the tryptic digestion of the captured bacteria under microwave heating for only 1-1.5 min prior to MALDI MS analysis. We identified the resulting biomarker ions by combining their MS/MS analysis results with protein database searches. Using this technique, we identified potential biomarker ions representing five gram-negative bacteria: Escherichia coli O157:H7, uropathogenic E. coli, Shigella sonnei, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Finally, we demonstrated the practical feasibility of using this approach to rapidly characterize bacteria in clinical samples. PMID:19007241

  20. Functional nanoparticle-based proteomic strategies for characterization of pathogenic bacteria.

    PubMed

    Chen, Wei-Jen; Tsai, Pei-Jane; Chen, Yu-Chie

    2008-12-15

    Although matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) can be employed to rapidly characterize pathogenic bacteria, bacterial cultures are generally required to obtain sufficient quantities of the bacterial cells prior to MALDI MS analysis. If this time-consuming step could be eliminated, the length of time required for identification of bacterial strains would be greatly reduced. In this paper, we propose an effective means of rapidly identifying bacteria--one that does not require bacterial culturing--using functional nanoparticle-based proteomic strategies that are characterized by extremely short analysis time. In this approach, we used titania-coated magnetic iron oxide nanoparticles (Fe(3)O(4)@TiO(2) NPs) as affinity probes to concentrate the target bacteria. The magnetic properties of the Fe(3)O(4)@TiO(2) NPs allow the conjugated target species to be rapidly isolated from the sample solutions under a magnetic field. Taking advantage of the absorption of the magnetic Fe(3)O(4) NPs in the microwave region of the electromagnetic spectrum, we performed the tryptic digestion of the captured bacteria under microwave heating for only 1-1.5 min prior to MALDI MS analysis. We identified the resulting biomarker ions by combining their MS/MS analysis results with protein database searches. Using this technique, we identified potential biomarker ions representing five gram-negative bacteria: Escherichia coli O157:H7, uropathogenic E. coli, Shigella sonnei, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Finally, we demonstrated the practical feasibility of using this approach to rapidly characterize bacteria in clinical samples.

  1. Anti-virulence potential of eugenyl acetate against pathogenic bacteria of medical importance.

    PubMed

    Musthafa, Khadar Syed; Voravuthikunchai, Supayang Piyawan

    2015-03-01

    Considering the role of virulence factors in bacterial pathogenicity, interfering with the virulence factor production could afford a novel way for the treatment of infections caused by pathogenic bacteria. In the present study, an effect of eugenyl acetate (EA), a well-known phytochemical from Syzygium aromaticum (clove bud) was assessed for its anti-virulence potential against both Gram-negative and Gram-positive pathogens. Eugenyl acetate at 150 µg/ml, significantly inhibited virulence factor production such as pyocyanin and pyoverdin by Pseudomonas aeruginosa ATCC 27853 up to 9.4 (P < 0.01) and 3.7 fold (P < 0.01), respectively. In addition, protease activity of P. aeruginosa was significantly reduced upon treatment with EA (P < 0.05). The test compound (150 µg/ml) lowered haemolytic activity of Staphylococcus aureus ATCC 29213 up to tenfold (P < 0.01). Furthermore, a decrease in staphyloxanthin pigment production was observed when S. aureus cells were treated with increasing concentrations of EA (37.5-150 µg/ml). The test compound at 75 µg/ml exhibited quorum sensing inhibitory potential in inhibiting violacein production by Chromobacterium violaceum DMST 21761 up to 27.7 fold (P < 0.01). Thus, results of the present work reveal the potential of EA as an alternative candidate to control pathogenicity of both Gram-negative and Gram-positive organisms. PMID:25613850

  2. Lactobacillus protects the integrity of intestinal epithelial barrier damaged by pathogenic bacteria

    PubMed Central

    Yu, Qinghua; Yuan, Lixia; Deng, Jun; Yang, Qian

    2015-01-01

    Pathogens invade intestinal mucosal barrier through phagocytosis of antigen presenting cells (dendritic cell, microfold cells), or through the invasion into the intestinal epithelial directly. Some pathogens could damage the cell junction between epithelial cells and use the paracellular pathway as an entrance to invade. Moreover, some Lactobacillus could inhibit the adhesion of the pathogens and protect the integrity of the cell junction and mucosal barrier. This research focused on the potential therapeutic effect of Lactobacillus fructosus (L. fructosus) C2 to attenuate ETEC K88 or S. typhimurium SL1344 induced changes to mucosal barrier. The results demonstrated that treatment of polarized Caco-2 cells with L. fructosus C2 reduced the permeation of dextran, and expression of IL-8, p-ERK, and p-JNK when cells were infected with pathogenic bacteria. The findings indicated that L. fructosus C2 exerted a protective effect against the damage to the integrity of Caco-2 cells by ETEC or S. typhimurium infection. PMID:25859435

  3. Modulation of Stat-1 in Human Macrophages Infected with Different Species of Intracellular Pathogenic Bacteria

    PubMed Central

    Dominici, Sabrina; Rinaldi, Laura; Cangiano, Alfonsina Mariarosaria; Brandi, Giorgio; Magnani, Mauro

    2016-01-01

    The infection of human macrophages by pathogenic bacteria induces different signaling pathways depending on the type of cellular receptors involved in the microorganism entry and on their mechanism(s) of survival and replication in the host cell. It was reported that Stat proteins play an important role in this process. In the present study, we investigate the changes in Stat-1 activation (phosphorylation in p-tyr701) after uptake of two Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and two Gram-negative bacteria (Salmonella typhimurium and Legionella pneumophila) characterized by their varying abilities to enter, survive, and replicate in human macrophages. Comparing the results obtained with Gram-negative and Gram-positive bacteria, Stat-1 activation in macrophages does not seem to be related to LPS content. The p-tyr701Stat-1 expression levels were found to be independent of the internalized bacterial number and IFN-γ release. On the contrary, Jak/Stat-1 pathway activation only occurs when an active infection has been established in the host macrophage, and it is plausible that the differences in the expression levels of p-tyr701Stat-1 could be due to different survival mechanisms or to differences in bacteria life cycles within macrophages. PMID:27437406

  4. Modulation of Stat-1 in Human Macrophages Infected with Different Species of Intracellular Pathogenic Bacteria.

    PubMed

    Schiavano, Giuditta Fiorella; Dominici, Sabrina; Rinaldi, Laura; Cangiano, Alfonsina Mariarosaria; Brandi, Giorgio; Magnani, Mauro

    2016-01-01

    The infection of human macrophages by pathogenic bacteria induces different signaling pathways depending on the type of cellular receptors involved in the microorganism entry and on their mechanism(s) of survival and replication in the host cell. It was reported that Stat proteins play an important role in this process. In the present study, we investigate the changes in Stat-1 activation (phosphorylation in p-tyr701) after uptake of two Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and two Gram-negative bacteria (Salmonella typhimurium and Legionella pneumophila) characterized by their varying abilities to enter, survive, and replicate in human macrophages. Comparing the results obtained with Gram-negative and Gram-positive bacteria, Stat-1 activation in macrophages does not seem to be related to LPS content. The p-tyr701Stat-1 expression levels were found to be independent of the internalized bacterial number and IFN-γ release. On the contrary, Jak/Stat-1 pathway activation only occurs when an active infection has been established in the host macrophage, and it is plausible that the differences in the expression levels of p-tyr701Stat-1 could be due to different survival mechanisms or to differences in bacteria life cycles within macrophages. PMID:27437406

  5. Use of mild irradiation doses to control pathogenic bacteria on meat trimmings for production of patties aiming at provoking minimal changes in quality attributes.

    PubMed

    Xavier, Ma de la Paz; Dauber, Cecilia; Mussio, Paula; Delgado, Enrique; Maquieira, Ana; Soria, Alejandra; Curuchet, Ana; Márquez, Rosa; Méndez, Carlos; López, Tomás

    2014-11-01

    The objectives of the present work were to assess the use of moderate doses of gamma irradiation (2 to 5 kGy) and to reduce the risk of pathogen presence without altering the quality attributes of bovine trimmings and of patties made of irradiated trimmings. Microbiological indicators (coliforms, Pseudomonas spp and mesophilic aerobic counts), physicochemical indicators (pH, color and tiobarbituric acid) and sensory changes were evaluated during storage. 5 kGy irradiation doses slightly increased off flavors in patties. Two pathogenic markers (Listeria monocytogenes and Escherichia coli O157:H7) were inoculated at high or low loads to trimming samples which were subsequently irradiated and lethality curves were obtained. Provided that using irradiation doses ≤2.5 kGy are used, reductions of 2 log CFU/g of L. monocytogenes and 5 log CFU/g of E. coli O157:H7 are expected. It seems reasonable to suppose that irradiation can be successfully employed to improve the safety of frozen trimmings when initial pathogenic bacteria burdens are not extremely high. PMID:25042241

  6. The Effects of Allium sativum Extracts on Biofilm Formation and Activities of Six Pathogenic Bacteria

    PubMed Central

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2015-01-01

    Background: Garlic is considered a rich source of many compounds, which shows antimicrobial effects. The ability of microorganisms to adhere to both biotic and abiotic surfaces and to form biofilm is responsible for a number of diseases of chronic nature, demonstrating extremely high resistance to antibiotics. Bacterial biofilms are complex communities of sessile microorganisms, embedded in an extracellular matrix and irreversibly attached to various surfaces. Objectives: The present study evaluated the antimicrobial activity of Allium sativum extract against the biofilms of six pathogenic bacteria and their free-living forms. The clinical isolates in this study had not been studied in any other studies, especially in regard to biofilm disruption and inhibition of biofilm cell metabolic activity. Materials and Methods: Antimicrobial activities of A. sativum L. extracts (methanol and ethanol extracts) against planktonic forms of bacteria were determined using the disc diffusion method. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values were evaluated by a macrobroth dilution technique. The anti-biofilm effects were assessed by microtiter plate method. Results: The results showed that the A. sativum L. extract discs did not have any zone of inhibition for the tested bacteria. However, The MIC values of A. sativum L. extracts (0.078 - 2.5 mg/mL) confirmed the high ability of these extracts for inhibition of planktonic bacteria. A. sativum L. extracts were efficient to inhibit biofilm structures and the concentration of each extract had a direct relation with the inhibitory effect. Conclusions: Finally, it can be suggested that the extracts of this plant be applied as antimicrobial agents against these pathogens, particularly in biofilm forms. PMID:26464762

  7. Effect of ionizing dose rate on the radioresistance of some food pathogenic bacteria.

    PubMed

    Dion, P; Charbonneau, R; Thibault, C

    1994-05-01

    Food pathogenic bacteria including Listeria monocytogenes (1A1 and ATCC 19111), Staphylococcus aureus (GD13 and ATCC 13565), Escherichia coli O157:H7 (ATCC 35150), Salmonella typhimurium, Yersinia enterocolitica, Vibrio parahaemolyticus, and Campylobacter jejuni were exposed to various rates of ionizing radiation (0.78, 2.6, and 22 kGy/h) emitted by three different 60Co irradiators. D10 values (D10 is the radiation dose required to eliminate 90% of a bacterial population (one logarithmic cycle reduction)) were calculated for the various strains and growth conditions tested. A covariance analysis of these results revealed that the dose rates studied had no significant influence on the radiosensitivity of these bacteria. At all dose rates, the bacteria were more radiosensitive when irradiated in a saline solution (0.85% NaCl) than in a chicken breast meat suspension. The growth phase of the bacterial population had a variable influence on its radioresistance. For L. monocytogenes 1A1, Staphylococcus aureus ATCC 13565, E. coli O157:H7, Y. enterocolitica, and V. parahaemolyticus, radioresistance was not significantly different in the exponential and stationary phases. Populations of L. monocytogenes ATCC 19111 and Staphylococcus aureus GD13 were significantly more resistant in the stationary phase (D10 = 0.23 and 0.12 kGy, respectively) than in the exponential phase (D10 = 0.17 and 0.09 kGy, respectively). Among the pathogenic bacteria investigated in this study, the most radioresistant was L. monocytogenes (D10 = 0.16-0.38 kGy, Gram-positive bacilli) and the most radiosensitive was V. parahaemolyticus (D10 = 0.03-0.04 kGy, halophilic Gram-negative bacilli). PMID:8069779

  8. Single Walled Carbon Nanotube-Based Electrical Biosensor for the Label-Free Detection of Pathogenic Bacteria.

    PubMed

    Yoo, Seung Min; Baek, Youn-Kyoung; Shin, SunHaeRa; Kim, Ju-Hyun; Jung, Hee-Tae; Choi, Yang-Kyu; Lee, Sang Yup

    2016-06-01

    We herein describe the development of a single-walled carbon nanotube (SWNT)-based electrical biosensor consisting of a two-terminal resistor, and report its use for the specific, label-free detection of pathogenic bacteria via changes in conductance. The ability of this biosensor to recognize different pathogenic bacteria was analyzed, and conditions were optimized with different probe concentrations. Using this system, the reference strains and clinical isolates of Staphylococcus aureus and Escherichia coli were successfully detected; in both cases, the sensor showed a detection limit of 10 CFU. This SWNT-based electrical biosensor will prove useful for the development of highly sensitive and specific handheld pathogen detectors.

  9. Autoinducer-2 activity of gram-negative foodborne pathogenic bacteria and its influence on biofilm formation.

    PubMed

    Yoon, Y; Sofos, J N

    2008-04-01

    This study evaluated whether autoinducer-2 (AI-2) activity would be associated with biofilm formation by Salmonella and Escherichia coli O157:H7 strains on food contact surfaces. In study I, a Salmonella Typhimurium DT104 strain and an E. coli O157:H7 strain, both AI-2 positive, were individually inoculated into 50 mL of Luria-Bertani (LB) or LB + 0.5% glucose (LBG) broth, without or with stainless steel or polypropylene (Salmonella) coupons. At 0, 14 (Salmonella), 24, 48, and 72 h of storage (25 degrees C), cells in suspension and detached cells from the coupons, obtained by vortexing, were enumerated on tryptic soy agar. In study II, a Salmonella Thompson AI-2-positive strain and an AI-2-negative strain, and an E. coli O157:H7 AI-2-positive strain and an AI-2-negative strain were inoculated into LB broth with stainless steel coupons. Cells were enumerated as in study I. In both studies, AI-2 activity was determined in cell-free supernatants. Cell numbers of S. Typhimurium DT104 on biofilms were higher (P < 0.05) in LB than those in LBG, while the E. coli O157:H7 strain showed no difference (P>or= 0.05) in biofilm cell counts between LB and LBG after storage for 72 h. Both S. Typhimurium DT104 and E. coli O157:H7 strains produced higher (P < 0.05) AI-2 activity in LBG than LB cell suspensions. Cell counts of AI-2-positive and-negative S. Thompson and E. coli O157:H7 strains were not different (P>or= 0.05) within suspensions or coupons (study II). The results indicated that, under the conditions of this study, AI-2 activity of the pathogen strains tested may not have a major influence on biofilm formation on food contact surfaces, which was similar between AI-2-positive and -negative strains.

  10. Released products of pathogenic bacteria stimulate biofilm formation by Escherichia coli K-12 strains.

    PubMed

    Vacheva, Anna; Ivanova, Radka; Paunova-Krasteva, Tsvetelina; Stoitsova, Stoyanka

    2012-06-01

    It has recently been shown that pathogens with a limited capacity for sessile growth (like some Escherichia coli O157 strains) can benefit from the presence of other bacteria and form mixed biofilms with companion strains. This study addresses the question whether pathogens may influence attached growth of E. coli non-pathogenic strains via secreted factors. We compared the biofilm-modulating effects of sterile stationary-phase culture media of a biofilm non-producing strain of E. coli O157:H, a laboratory biofilm-producing E. coli K-12 strain and a biofilm-forming strain of the pathogen Yersina enterocolitica O:3. Sessile growth was monitored as biomass (crystal violet assay), exopolysaccharide (ELLA) and morphology (scanning electron and confocal laser microscopy). With two of the E. coli K-12 strains stimulation of biofilm formation by all supernatants was achieved, but only the pathogens' secreted products induced biomass increase in some 'biofilm-deficient' K-12 strains. Lectin-peroxidase labeling indicated changes in colanic acid and poly-N-acetylglucosamine amounts in extracellular matrices. The contribution of indole, protein and polysaccharide to the biofilm-modulating activities of the supernatants was compared. Indole, in concentrations equal to those established in the supernatants, suppressed sessile growth in one K-12 strain. Proteinase K significantly reduced the stimulatory effects of all supernatants, indicating a prominent role of protein/peptide factor(s) in biofilm promotion. The amount of released polysaccharides (rPS) in the supernatants was quantitated then comparable quantities of isolated rPS were applied during biofilm growth. The three rPS had notable strain-specific effects with regard to both the strain-source of the rPS and the E. coli K-12 target strain.

  11. The impact of cyanobacteria on growth and death of opportunistic pathogenic bacteria.

    PubMed

    Bomo, Anne-Marie; Tryland, Ingun; Haande, Sigrid; Hagman, Camilla H C; Utkilen, Hans

    2011-01-01

    Climate change may cause increased microbial growth in water sources and more knowledge is required on how this may affect the hygienic water quality, i.e., whether increased occurrence of cyanobacteria and algae may stimulate the growth rate of opportunistic pathogenic bacteria. Laboratory experiments were performed to investigate if the presence of the cyanobacteria Anabanea lemmermannii and Microcystis aeruginosa affected the survival and growth rate of the opportunistic pathogenic bacteria Aeromonas hydrophila and Pseudomonas aeruginosa, and the faecal indicators Escherichia coli and coliforms. Cyanobacteria were cultured in bottles containing the nutrient-poor medium 02. Sewage, A. hydrophila or P. aeruginosa was added to cyanobacterial cultures and the bacterial growth and survival was followed. E. coli and coliforms from sewage died within few days and the decay rate was not affected by the presence of cyanobacteria. The presence of Anabaena stimulated the growth rate of P. aeruginosa, but had no effect on the growth rate of A. hydrophila. Microcystis had no effect on the growth rate of P. aeruginosa and an inhibiting effect on the growth rate of A. hydrophila. PMID:22097011

  12. Responses to Elevated c-di-GMP Levels in Mutualistic and Pathogenic Plant-Interacting Bacteria

    PubMed Central

    Pérez-Mendoza, Daniel; Aragón, Isabel M.; Prada-Ramírez, Harold A.; Romero-Jiménez, Lorena; Ramos, Cayo; Gallegos, María-Trinidad; Sanjuán, Juan

    2014-01-01

    Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels. PMID:24626229

  13. Responses to elevated c-di-GMP levels in mutualistic and pathogenic plant-interacting bacteria.

    PubMed

    Pérez-Mendoza, Daniel; Aragón, Isabel M; Prada-Ramírez, Harold A; Romero-Jiménez, Lorena; Ramos, Cayo; Gallegos, María-Trinidad; Sanjuán, Juan

    2014-01-01

    Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels. PMID:24626229

  14. The secreted fructose 1,6-bisphosphate aldolase as a broad spectrum vaccine candidate against pathogenic bacteria in aquaculture.

    PubMed

    Sun, Zhongyang; Shen, Binbing; Wu, Haizhen; Zhou, Xiangyu; Wang, Qiyao; Xiao, Jingfan; Zhang, Yuanxing

    2015-10-01

    The development of aquaculture has been hampered by different aquatic pathogens that can cause edwardsiellosis, vibriosis, or other diseases. Therefore, developing a broad spectrum vaccine against different fish diseases is necessary. In this study, fructose 1,6-bisphosphate aldolase (FBA), a conserved enzyme in the glycolytic pathway, was demonstrated to be located in the non-cytoplasmic components of five aquatic pathogenic bacteria and exhibited remarkable protection and cross-protection against these pathogens in turbot and zebrafish. Further analysis revealed that sera sampled from vaccinated turbot had a high level of specific antibody and bactericidal activity against these pathogens. Meanwhile, the increased expressions of immune response-related genes associated with antigen recognition and presentation indicated that the adaptive immune response was effectively aroused. Taken together, our results suggest that FBA can be utilized as a broad-spectrum vaccine against various pathogenic bacteria of aquaculture in the future.

  15. Influence of lactic acid bacteria on survival of Escherichia coli O157:H7 in inoculated Minas cheese during storage at 8.5 degrees C.

    PubMed

    Saad, S M; Vanzin, C; Oliveira, M N; Franco, B D

    2001-08-01

    Minas cheese is a typical Brazilian fresh cheese, manufactured by addition of rennin and CaCl2 to milk, followed by draining the curd. The intrinsic characteristics of this product make it favorable for growth of pathogens, including Escherichia coli O157:H7. The influence of the addition of a commercial mesophilic type O lactic culture to this product on the growth of this pathogen during storage at 8.5 degrees C was evaluated. Eight different formulations of Minas cheese were manufactured using raw or pasteurized milk and with or without salt and lactic culture. Individual portions of each formulation were transferred to sterile plastic bags and inoculated with E. coli O157:H7 to yield ca. 10(3) or 10(6) CFU/g. After blending by hand massaging the bags, samples were stored at 8.5 degrees C for up to 14 days. E. coli O157:H7 was counted after 1, 2, 7, and 14 days of storage using 3M Petrifilm Test Kit-HEC. Counts in samples without added lactic culture showed a 2-log increase in the first 24 h and remained constant during the following 14 days. Counts in samples with added lactic culture showed a 0.5-log increase in the first 24 h, followed by a decrease. These variations were statistically significant (P < 0.05). No significant variations (P > 0.05) were obtained for cheese samples manufactured with pasteurized or raw milk, with or without salt. Results indicate that the addition of type O lactic culture may be an additional safeguard to well-established good manufacturing practices and hazard analysis and critical control point programs in the control of growth of E. coli O157:H7 in Minas cheese. PMID:11510651

  16. Antimicrobial Property of Extracts of Indian Lichen against Human Pathogenic Bacteria.

    PubMed

    Srivastava, Priya; Upreti, D K; Dhole, T N; Srivastava, Apurva K; Nayak, Meghanand T

    2013-01-01

    Context. Usnea ghattensis G. Awasthi (Usneaceae) endemic fruticose lichen found growing luxuriantly in Northern Western Ghats of India, it also contains Usnic acid as a major chemical and tested against some human pathogenic bacteria. Objective. To explore antimicrobial properties of Usnea ghattensis against some human pathogenic bacteria. Materials and Methods. The lichen was extracted in acetone, methanol, and ethanol. In vitro antimicrobial activity was tested initially by Kirby-Bauer technique of disc diffusion method and was confirmed by minimum inhibitory concentration using Broth microdilution method according to the NCCLS guidelines. Results. Ethanol extract was most effective against Bacillus cereus and Pseudomonas aeruginosa with a zone of inhibition 29.8 ± 0.6 mm and 12.3 ± 0.5 mm diameters at a concentration of 0.2 mg/mL. Acetone and methanol extract demonstrated almost similar activity against Staphylococcus aureus and the zone of inhibition was 24.6 ± 0.5 and 24.7 ± 0.4 mm. Only methanol extract was showing activity against Streptococcus faecalis with a 13.5 ± 0.8 mm zone. MIC value noted against Staphylococcus aureus and Streptococcus faecalis was 6.25  μ g/mL and 25  μ g/mL, whereas against Bacillus cereus and Pseudomonas aeruginosa, MIC calculated was 3.125  μ g/mL and 200  μ g/mL, respectively. Conclusion. The present study demonstrates the relatively higher activity of this lichen against not only gram (+) but significantly also against gram (-) bacteria. This indicates that this lichen might be a rich source of effective antimicrobial agents. PMID:24062769

  17. Diarrhea-associated pathogens, lactobacilli and cellulolytic bacteria in equine feces: responses to antibiotic challenge.

    PubMed

    Harlow, Brittany E; Lawrence, Laurie M; Flythe, Michael D

    2013-09-27

    Antibiotics are important to equine medicine, but antibiotic-associated diarrhea (AAD) can lead to poor performance and even mortality. AAD is attributed to disruption of the hindgut microbiota, which permits proliferation of pathogenic microbes. The goal of this study was to evaluate the effects of common antibiotics on cellulolytic bacteria, lactobacilli, and AAD-associated pathogens in the feces of healthy horses. Fifteen horses were assigned to three treatment groups (blocked by age and sex): control (no antibiotics), trimethoprim-sulfadiazine (PO), or ceftiofur (IM). Fecal samples (n=8 per horse) were taken during dietary adaptation (3 weeks), antibiotic challenge (1 week), and withdrawal (1 week). Bacteria were enumerated by serial dilution and viable count. Cellulolytic bacteria decreased by >99% during administration of either antibiotic (P<0.0001) and were still less than controls at the end of the withdrawal period (P<0.0001). Fecal samples from horses challenged with ceftiofur had 75% fewer lactobacilli than those from control horses at the end of the antibiotic challenge period (P<0.05). Antibiotic challenged horses also shed more salmonella than control horses (P<0.05). Antibiotics had no effect on the number of Clostridium perfringens isolates. There was no detectable Clostridium difficile during adaptation or in any control horse. C. difficile increased (P<0.0001) to approximately 10(4)cfu/g when horses were challenged with antibiotics, and were still detectable 1 week after withdrawal. These results indicate that antibiotics can disrupt the normal gastrointestinal microbiota and allow proliferation of Salmonella spp. and C. difficile.

  18. Effect of plant growth-promoting bacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) inoculation on oats in saline-alkali soil contaminated by petroleum to enhance phytoremediation.

    PubMed

    Xun, Feifei; Xie, Baoming; Liu, Shasha; Guo, Changhong

    2015-01-01

    To investigate the effect of plant growth-promoting bacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on phytoremediation in saline-alkali soil contaminated by petroleum, saline-alkali soil samples were artificially mixed with different amount of oil, 5 and 10 g/kg, respectively. Pot experiments with oat plants (Avena sativa) were conducted under greenhouse condition for 60 days. Plant biomass, physiological parameters in leaves, soil enzymes, and degradation rate of total petroleum hydrocarbon were measured. The result demonstrated that petroleum inhibited the growth of the plant; however, inoculation with PGPR in combination with AMF resulted in an increase in dry weight and stem height compared with noninoculated controls. Petroleum stress increased the accumulation of malondialdehyde (MDA) and free proline and the activities of the antioxidant enzyme such as superoxide dismutase, catalase, and peroxidase. Application of PGPR and AMF augmented the activities of three enzymes compared to their respective uninoculated controls, but decreased the MDA and free proline contents, indicating that PGPR and AMF could make the plants more tolerant to harmful hydrocarbon contaminants. It also improved the soil quality by increasing the activities of soil enzyme such as urease, sucrase, and dehydrogenase. In addition, the degradation rate of total petroleum hydrocarbon during treatment with PGPR and AMF in moderately contaminated soil reached a maximum of 49.73%. Therefore, we concluded the plants treated with a combination of PGPR and AMF had a high potential to contribute to remediation of saline-alkali soil contaminated with petroleum.

  19. Bacteria-zinc co-localization implicates enhanced synthesis of cysteine-rich peptides in zinc detoxification when Brassica juncea is inoculated with Rhizobium leguminosarum.

    PubMed

    Adediran, Gbotemi A; Ngwenya, Bryne T; Mosselmans, J Frederick W; Heal, Kate V

    2016-01-01

    Some plant growth promoting bacteria (PGPB) are enigmatic in enhancing plant growth in the face of increased metal accumulation in plants. Since most PGPB colonize the plant root epidermis, we hypothesized that PGPB confer tolerance to metals through changes in speciation at the root epidermis. We employed a novel combination of fluorophore-based confocal laser scanning microscopic imaging and synchrotron based microscopic X-ray fluorescence mapping with X-ray absorption spectroscopy to characterize bacterial localization, zinc (Zn) distribution and speciation in the roots of Brassica juncea grown in Zn contaminated media (400 mg kg(-1) Zn) with the endophytic Pseudomonas brassicacearum and rhizospheric Rhizobium leguminosarum. PGPB enhanced epidermal Zn sequestration relative to PGBP-free controls while the extent of endophytic accumulation depended on the colonization mode of each PGBP. Increased root accumulation of Zn and increased tolerance to Zn was associated predominantly with R. leguminosarum and was likely due to the coordination of Zn with cysteine-rich peptides in the root endodermis, suggesting enhanced synthesis of phytochelatins or glutathione. Our mechanistic model of enhanced Zn accumulation and detoxification in plants inoculated with R. leguminosarum has particular relevance to PGPB enhanced phytoremediation of soils contaminated through mining and oxidation of sulphur-bearing Zn minerals or engineered nanomaterials such as ZnS. PMID:26263508

  20. Rapid evolutionary adaptation to elevated salt concentrations in pathogenic freshwater bacteria Serratia marcescens.

    PubMed

    Ketola, Tarmo; Hiltunen, Teppo

    2014-10-01

    Rapid evolutionary adaptions to new and previously detrimental environmental conditions can increase the risk of invasion by novel pathogens. We tested this hypothesis with a 133-day-long evolutionary experiment studying the evolution of the pathogenic Serratia marcescens bacterium at salinity niche boundary and in fluctuating conditions. We found that S. marcescens evolved at harsh (80 g/L) and extreme (100 g/L) salt conditions had clearly improved salt tolerance than those evolved in the other three treatments (ancestral conditions, nonsaline conditions, and fluctuating salt conditions). Evolutionary theories suggest that fastest evolutionary changes could be observed in intermediate selection pressures. Therefore, we originally hypothesized that extreme conditions, such as our 100 g/L salinity treatment, could lead to slower adaptation due to low population sizes. However, no evolutionary differences were observed between populations evolved in harsh and extreme conditions. This suggests that in the study presented here, low population sizes did not prevent evolution in the long run. On the whole, the adaptive potential observed here could be important for the transition of pathogenic S. marcescens bacteria from human-impacted freshwater environments, such as wastewater treatment plants, to marine habitats, where they are known to infect and kill corals (e.g., through white pox disease).

  1. Colorimetric detection of pathogenic bacteria using platinum-coated magnetic nanoparticle clusters and magnetophoretic chromatography.

    PubMed

    Kwon, Donghoon; Lee, Sanghee; Ahn, Myung Mo; Kang, In Seok; Park, Ki-Hwan; Jeon, Sangmin

    2015-07-01

    A colorimetric method that uses platinum-coated magnetic nanoparticle clusters (Pt/MNCs) and magnetophoretic chromatography is developed to detect pathogenic bacteria. Half-fragments of monoclonal Escherichia coli O157:H7 (EC) antibodies were functionalized to Pt/MNCs and used to capture E. coli bacteria in milk. After magnetic separation of free Pt/MNCs and Pt/MNC-EC complexes from the milk, a precision pipette was used to imbibe the E. coli-containing solution, then a viscous polyethylene glycol solution. Due to difference in viscosities, the solutions separate into two liquid layers inside the pipette tip. The Pt/MNC-EC complexes were separated from the free Pt/MNCs by applying an external magnetic field, then added to a tetramethylbenzidine (TMB) solution. Catalytic oxidation of TMB by Pt produced color changes of the solution, which enabled identification of the presence of 10 cfu mL(-1) E. coli bacteria with the naked eye. The total assay time including separation, binding and detection was 30 min.

  2. Potential pathogenic bacteria in metalworking fluids and aerosols from a machining facility.

    PubMed

    Perkins, Sarah D; Angenent, Largus T

    2010-12-01

    The metalworking and machining industry utilizes recirculating metalworking fluids for integral aspects of the fabrication process. Despite the use of biocides, these fluids sustain substantial biological growth. Subsequently, the high-shear forces incurred during metalworking processing aerosolize bacterial cells and may cause dermatologic and respiratory effects in exposed workers. We quantified and identified the bacterial load for metalworking fluid and aerosol samples of a machining facility in the US Midwest during two seasons. To investigate the presence of potentially pathogenic bacteria in fluid and air, we performed 16S rRNA gene surveys. The concentration of total bacterial cells (including culturable and nonculturable cells) was relatively constant throughout the study, averaging 5.1 × 10⁸ cells mL⁻¹ in the fluids and 4.8 × 10⁵ cells m⁻³ in the aerosols. We observed bacteria of potential epidemiologic significance from several different bacterial phyla in both fluids and aerosols. Most notably, Alcaligenes faecalis was identified through both direct sequencing and culturing in every sample collected. Elucidating the bacterial community with gene surveys showed that metalworking fluids were the source of the aerosolized bacteria in this facility. PMID:20955193

  3. Toxicity of hydrogen peroxide produced by electroplated coatings to pathogenic bacteria.

    PubMed

    Zhao, Z H; Sakagami, Y; Osaka, T

    1998-05-01

    The ability of various electroplated coatings (cobalt, zinc, copper, and cobalt-containing alloys of nickel, zinc, chromium, etc.) to inhibit the growth of pathogenic bacteria (Gram-positive bacteria Enterococcus faecalis and methicillin-resistant Staphylococcus aureus and Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae) was determined by a drop-method antibacterial experiment. The amounts of H2O2 produced and metal ions dissolved from the surfaces of various electroplated coatings were measured and it was found that the inhibitory ability of coatings corresponded to the amounts of H2O2 produced. The more significant the inhibition of the coating to bacterial growth, the greater the amount of H2O2 production. In addition, the bacterial survival rates on the surfaces of coatings were almost zero when H2O2 was produced in amounts greater than 10(-6) mmol/cm2. However, the dominant concentrations of metal ions dissolved from coatings were outside of the bacterial lethal range.

  4. Channel formation by RTX-toxins of pathogenic bacteria: Basis of their biological activity.

    PubMed

    Benz, Roland

    2016-03-01

    The pore-forming cytolysins of the RTX-toxin (Repeats in ToXin) family are a relatively small fraction of a steadily increasing family of proteins that contain several functionally important glycine-rich and aspartate containing nonapeptide repeats. These cytolysins produced by a variety of Gram-negative bacteria form ion-permeable channels in erythrocytes and other eukaryotic cells. Hemolytic and cytolytic RTX-toxins represent pathogenicity factors of the toxin-producing bacteria and are very often important key factors in pathogenesis of the bacteria. Channel formation by RTX-toxins lead to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. Here we discuss channel formation and channel properties of some of the best known RTX-toxins, such as α-hemolysin (HlyA) of Escherichia coli and the uropathogenic EHEC strains, the adenylate cyclase toxin (ACT, CyaA) of Bordetella pertussis and the RTX-toxins (ApxI, ApxII and ApxIII) produced by different strains of Actinobacillus pleuropneumoniae. The channels formed by these RTX-toxins in lipid bilayers share some common properties such as cation selectivity and voltage-dependence. Furthermore the channels are transient and show frequent switching between different ion-conducting states. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.

  5. Photocatalytic degradation of pathogenic bacteria with AgI/TiO2 under visible light irradiation.

    PubMed

    Hu, Chun; Guo, Jian; Qu, Jiuhui; Hu, Xuexiang

    2007-04-24

    The photocatalytic disinfection of pathogenic bacteria in water was investigated systematically with AgI/TiO2 under visible light (lambda > 420 nm) irradiation. The catalyst was found to be highly effective in killing Escherichia coli and Staphylococcus aureus. The adsorbed *OH and hVB+ on the surface of the catalyst were proposed to be the main active oxygen species by study of electron spin resonance and the effect of radical scavengers. The process of destruction of the cell wall and the cell membrane was verified by TEM, potassium ion leakage, lipid peroxidation, and FT-IR measurements. Some products from photocatalytic degradation of bacteria such as aldehydes, ketones, and carboxylic acids were identified by FT-IR spectroscopy. These results suggested that the photocatalytic degradation of the cell structure caused the cell death. The electrostatic force interaction of the bacteria-catalyst significantly affected the efficiency of disinfection on the basis of the E. coli inactivation under different conditions. PMID:17373834

  6. Development and application of a quantitative assay amenable for high-throughput screening to target the type II secretion system for new treatments against plant-pathogenic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant-pathogenic bacteria are the causative agents of diseases in important agricultural crops and ornamental plants. The severe economic burden of these diseases requires seeking new approaches, particularly because phytopathogenic bacteria are often resistant to currently available treatments. The...

  7. Spontaenous Avian Leukosis Virus-like lymphomas in specific-pathogen-free chickens inoculated with serotype 2 Marek’s disease virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chickens of Avian Disease and Oncology Laboratory (ADOL) line alv6, known to develop spontaneous avian leukosis virus (ALV)-like lymphomas at two years of age or older, were inoculated either in-ovo, or at 1 day of age with strain SB-1 of serotype 2 Marek’s disease virus (MDV). Inoculated and uninoc...

  8. Control of foodborne pathogens and soft-rot bacteria on bell pepper by three strains of bacterial antagonists.

    PubMed

    Liao, Ching-Hsing

    2009-01-01

    Forty-two representative strains of native bacteria associated with fresh peeled baby carrots were isolated and characterized. Two of these strains, identified as Pseudomonas fluorescens AG3A (Pf AG3A) and Bacillus YD1, were evaluated in conjunction with another known antagonist, P. fluorescens 2-79 (Pf 2-79), for their potential as biocontrol agents of human pathogens (Listeria monocytogenes, Yersinia enterocolitica, Salmonella enterica, and Escherichia coli O157:H7) and soft-rot bacteria (Erwinia carotovora subsp. carotovora, Pseudomonas marginalis, and Pseudomonas viridiflava). When grown on iron-deficient agar media, all three antagonists produced inhibition zones up to 25 mm in diameter against the growth of human pathogens and soft-rot bacteria. However, when grown on iron-rich agar media, only Pf 2-79 and Bacillus YD1 exhibited antimicrobial activity. Treatment of bell pepper disks with Pf 2-79 or Bacillus YD1 reduced the growth of pathogen by 1.4 to 4.1 log units, depending upon the ratio of the number of antagonist cells to pathogen cells (1:1, 10:1, 100:1, or 1,000:1). The greatest reduction was observed when 10- to 100-fold higher number of antagonists than pathogens was applied. Pf AG3A and Bacillus YD1 reduced the growth of pathogens on pepper disks at 20 degrees C but not at 10 degrees C. However, Pf 2-79 reduced the growth of L. monocytogenes and Y. enterocolitica by up to 4 log units at either 20 or 10 degrees C. Treatment of pepper disks with Pf 2-79 also reduced the incidence of soft rot induced by soft-rot bacteria by 40 to 70%. Pf 2-79 is the most effective of the three antagonists tested for control of spoilage bacteria and human pathogens on bell pepper.

  9. The blow fly, Chrysomya megacephala, and the house fly, Musca domestica, as mechanical vectors of pathogenic bacteria in Northeast Thailand.

    PubMed

    Chaiwong, T; Srivoramas, T; Sueabsamran, P; Sukontason, K; Sanford, M R; Sukontason, K L

    2014-06-01

    The Oriental latrine fly, Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) and the house fly, Musca domestica L., (Diptera: Muscidae) are synanthropic flies which are adapted to live in close association with human habitations, thereby making them likely mechanical vectors of several pathogens to humans. There were two main aims of this study. The first aim was to determine the prevalence of these two fly species from five types of human habitations including: fresh-food markets, garbage piles, restaurants, school cafeterias and paddy fields, in the Muang Ubon Ratchathani and Warinchamrap districts of Ubon Ratchathani province of Northeast Thailand. Flies collection were conducted monthly from September 2010-October 2011 using a reconstructable funnel trap, containing 1 day-tainted beef offal as bait. A total of 7 750 flies (6 401 C. megacephala and 1 349 M.domestica) were collected. The second aim was to examine the potential of these flies to carry pathogenic bacteria. Bacteria were isolated from 994 individual flies collected using a sweep net (555 C. megacephala and 439 M. domestica). A total of 15 bacterial genera were isolated from the external surfaces, comprising ten genera of gram-negative bacteria and five gram-positive bacteria. The most common bacteria isolated from both species were coagulase-negative staphylococci, followed by Streptococcus group D non-enterococci. Human pathogenic enteric bacteria isolated were Salmonella sp., Shigella sp., Escherichia coli O157:H7, Salmonella typhi, Bacillus sp., and Enterococcus sp., of which S. typhi is the first report of isolation from these fly species. Other human pathogens included Staphylococcus aureus and Pseudomonas aeruginosa. Not only were the number of C. megacephala positive for bacteria significantly higher than for M. domestica, but they were also carrying ~11-12 times greater bacterial load than M. domestica. These data suggest that both fly species should be considered potential

  10. Bacteriophages with Potential for Inactivation of Fish Pathogenic Bacteria: Survival, Host Specificity and Effect on Bacterial Community Structure

    PubMed Central

    Pereira, Carla; Silva, Yolanda J.; Santos, Ana L.; Cunha, Ângela; 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. PMID:22163184

  11. Prevalence of indicator and pathogenic bacteria in a tropical river of Western Ghats, India

    NASA Astrophysics Data System (ADS)

    Vincy, M. V.; Brilliant, R.; Pradeepkumar, A. P.

    2015-05-01

    The Meenachil, the only river that flows through the heart of the Kottayam district of Kerala state, India was selected for the study. The present study has been carried out with an objective to systematically examine the prevalence of indicator and pathogenic microorganisms and to compare the microbiological quality of the river water during the pre-monsoon and post-monsoon seasons. Water samples from 44 different sites during pre-monsoon and post-monsoon seasons were collected for the analysis. During the pre-monsoon period, the faecal coliform count ranged from 230 to 110,000 MPN/100 ml while there was a variation from 200 to 4600 MPN/100 ml during the post-monsoon period. When the faecal streptococci count was analysed, it ranged from 140 to 110,000 MPN/100 ml during the pre-monsoon and 70 to 4600 MPN/100 ml during the post-monsoon seasons, respectively. All the samples collected were found to have total viable count (TVC) higher than those prescribed by Bureau of Indian Standards (ISI 1991). Total viable counts were found in the range of 1.1 × 102 to 32 × 102 cfu/ml in the pre-monsoon and 1.0 × 102 to 26 × 102 cfu/ml in the post-monsoon. The presence of faecal indicator bacteria, Escherichia coli and potentially pathogenic bacteria, Vibrio cholerae, Vibrio parahaemolyticus and Salmonella enterica in the Meenachil River indicates that the bacteriological quality of the Meenachil River is poor. Moreover, it sheds light to the fact that raw sewage is being dumped into the Meenachil River. Urban runoffs and effluents of rubber factories appear to be the important sources of faecal contamination in the river. From this study, we conclude that these water bodies pose significant public health hazards. Adequate sanitary infrastructure will help in preventing source water contamination. Besides this, public health education aimed at improving personal, household and community hygiene is urgent.

  12. [Development of molecular detection of food-borne pathogenic bacteria using miniaturized microfluidic devices].

    PubMed

    Iván, Kristóf; Maráz, Anna

    2015-12-20

    Detection and identification of food-borne pathogenic bacteria are key points for the assurance of microbiological food safety. Traditional culture-based methods are more and more replaced by or supplemented with nucleic acid based molecular techniques, targeting specific (preferably virulence) genes in the genomes. Internationally validated DNA amplification - most frequently real-time polymerase chain reaction - methods are applied by the food microbiological testing laboratories for routine analysis, which will result not only in shortening the time for results but they also improve the performance characteristics (e.g. sensitivity, specificity) of the methods. Beside numerous advantages of the polymerase chain reaction based techniques for routine microbiological analysis certain drawbacks have to be mentioned, such as the high cost of the equipment and reagents, as well as the risk of contamination of the laboratory environment by the polymerase chain reaction amplicons, which require construction of an isolated laboratory system. Lab-on-a-chip systems can integrate most of these laboratory processes within a miniaturized device that delivers the same specificity and reliability as the standard protocols. The benefits of miniaturized devices are: simple - often automated - use, small overall size, portability, sterility due to single use possibility. These miniaturized rapid diagnostic tests are being researched and developed at the best research centers around the globe implementing various sample preparation and molecular DNA amplification methods on-chip. In parallel, the aim of the authors' research is to develop microfluidic Lab-on-a-chip devices for the detection and identification of food-borne pathogenic bacteria.

  13. Short communication: Lactic acid bacteria from the honeybee inhibit the in vitro growth of mastitis pathogens.

    PubMed

    Piccart, K; Vásquez, A; Piepers, S; De Vliegher, S; Olofsson, T C

    2016-04-01

    Despite the increasing knowledge of prevention and control strategies, bovine mastitis remains one of the most challenging diseases in the dairy industry. This study investigated the antimicrobial activity of 13 species of lactic acid bacteria (LAB), previously isolated from the honey crop of the honeybee, on several mastitis pathogens. The viable LAB were first reintroduced into a sterilized heather honey matrix. More than 20 different bovine mastitis isolates were tested against the mixture of the 13 LAB species in the honey medium using a dual-culture overlay assay. The mastitis isolates were identified through bacteriological culturing, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Additionally, the mastitis isolates were subjected to antimicrobial susceptibility testing through disk diffusion. Growth of all tested mastitis pathogens, including the ones displaying antimicrobial resistance to one or more antimicrobial compounds, were inhibited to some extent by the honey and LAB combination. The antibacterial effect of these LAB opens up new perspectives on alternative treatment and prevention of bovine mastitis.

  14. Diversity of honey stores and their impact on pathogenic bacteria of the honeybee, Apis mellifera

    PubMed Central

    Erler, Silvio; Denner, Andreas; Bobiş, Otilia; Forsgren, Eva; Moritz, Robin F A

    2014-01-01

    Honeybee colonies offer an excellent environment for microbial pathogen development. The highest virulent, colony killing, bacterial agents are Paenibacillus larvae causing American foulbrood (AFB), and European foulbrood (EFB) associated bacteria. Besides the innate immune defense, honeybees evolved behavioral defenses to combat infections. Foraging of antimicrobial plant compounds plays a key role for this “social immunity” behavior. Secondary plant metabolites in floral nectar are known for their antimicrobial effects. Yet, these compounds are highly plant specific, and the effects on bee health will depend on the floral origin of the honey produced. As worker bees not only feed themselves, but also the larvae and other colony members, honey is a prime candidate acting as self-medication agent in honeybee colonies to prevent or decrease infections. Here, we test eight AFB and EFB bacterial strains and the growth inhibitory activity of three honey types. Using a high-throughput cell growth assay, we show that all honeys have high growth inhibitory activity and the two monofloral honeys appeared to be strain specific. The specificity of the monofloral honeys and the strong antimicrobial potential of the polyfloral honey suggest that the diversity of honeys in the honey stores of a colony may be highly adaptive for its “social immunity” against the highly diverse suite of pathogens encountered in nature. This ecological diversity may therefore operate similar to the well-known effects of host genetic variance in the arms race between host and parasite. PMID:25505523

  15. Effects of pesticides on the reduction of plant and human pathogenic bacteria in application water.

    PubMed

    Mahovic, Michael; Gu, Ganyu; Rideout, Steven

    2013-04-01

    Overhead spray applications of in-field tomato treatments dissolved in aqueous solutions have specific pest targets (fungal, bacterial, insect, or other). Any organism present in the solution or on treated plant surfaces that is not a specific target of the application is unlikely inactivated and can instead be spread through the phyllosphere. In this laboratory study, commercially labeled pesticides (including Actigard 50WG, Bravo Weather Stik 6F, Cabrio 20EG, Kasumin, Kocide 3000 46WG, Oxidate 27L, Penncozeb 75DF, ProPhyt 54.5L, Stimplex 100L, Firewall, 22.4WP, and Tanos 50DF) in common use in commercial tomato production fields of the Eastern Shore of Virginia were investigated for activity against in vitro bacterial contamination of pesticide application waters. Pesticides of interest were tank mixed individually with one of the plant pathogens Ralstonia solanacearum, Xanthomonas campestris pv. vesicatoria, Pseudomonas syringae pv. tomato, Erwinia carotovora subsp. carotovora, or one of two serovars (Newport and Montevideo) of the human pathogen Salmonella enterica to assess reduction values during the average time between mixing and initial application. Observations suggested that while some treatments had a noticeable effect on population levels, only the oxidizer, peroxyacetic acid, showed significant and consistent levels of suppression against all bacteria investigated, at levels that could have practical implications. PMID:23575141

  16. A Sensitive and simple macrophage-based electrochemical biosensor for evaluating lipopolysaccharide cytotoxicity of pathogenic bacteria.

    PubMed

    Wang, Xiumei; Zhu, Pei; Pi, Fuwei; Jiang, Hui; Shao, Jingdong; Zhang, Yinzhi; Sun, Xiulan

    2016-07-15

    In this study, a sensitive and simple electrochemical murine macrophage (Ana-1) cell sensor has been developed for early detection of lipopolysaccharides (LPS) to evaluate the toxicity of pathogenic bacteria. Magnetic glassy carbon electrode (MGCE), which possesses excellent reproducibility and regeneration qualities, was modified with a nanocomposite to improve electrochemical signals and enhance the sensitivity. The synthesized magnetic nanoparticles (MNPs) were internalized into murine macrophages, which completed the immobilization of macrophages onto the modified electrode for evaluating the cytotoxicity of LPS by electrochemical impedance spectroscopy (EIS). The MNPs facilitated reusability of the proposed sensor by allowing removal of the magnetic core from the electrode. Our results indicated that LPS caused a marked decrease in electrochemical impedance in a dose-dependent manner in range of 1-5μg/mL. By SEM, we found that microvilli on the plasma membrane became scarce and the membrane became smooth on cells incubated with LPS, which lessens the absorption of cells to reduce the impedance. And biological assay indicated that EIS patterns were correlated with the calcium concentration in cells, and suggested that [Ca(2+)]i production increased in cells incubated with LPS and its mobilization altered electrochemical signals. Compared with conventional methods, this electrochemical test is inexpensive, highly sensitive, and has a quick response, and thus provides a new avenue for evaluating the cytotoxicity of pathogens.

  17. A Sensitive and simple macrophage-based electrochemical biosensor for evaluating lipopolysaccharide cytotoxicity of pathogenic bacteria.

    PubMed

    Wang, Xiumei; Zhu, Pei; Pi, Fuwei; Jiang, Hui; Shao, Jingdong; Zhang, Yinzhi; Sun, Xiulan

    2016-07-15

    In this study, a sensitive and simple electrochemical murine macrophage (Ana-1) cell sensor has been developed for early detection of lipopolysaccharides (LPS) to evaluate the toxicity of pathogenic bacteria. Magnetic glassy carbon electrode (MGCE), which possesses excellent reproducibility and regeneration qualities, was modified with a nanocomposite to improve electrochemical signals and enhance the sensitivity. The synthesized magnetic nanoparticles (MNPs) were internalized into murine macrophages, which completed the immobilization of macrophages onto the modified electrode for evaluating the cytotoxicity of LPS by electrochemical impedance spectroscopy (EIS). The MNPs facilitated reusability of the proposed sensor by allowing removal of the magnetic core from the electrode. Our results indicated that LPS caused a marked decrease in electrochemical impedance in a dose-dependent manner in range of 1-5μg/mL. By SEM, we found that microvilli on the plasma membrane became scarce and the membrane became smooth on cells incubated with LPS, which lessens the absorption of cells to reduce the impedance. And biological assay indicated that EIS patterns were correlated with the calcium concentration in cells, and suggested that [Ca(2+)]i production increased in cells incubated with LPS and its mobilization altered electrochemical signals. Compared with conventional methods, this electrochemical test is inexpensive, highly sensitive, and has a quick response, and thus provides a new avenue for evaluating the cytotoxicity of pathogens. PMID:26991601

  18. Living biointerfaces based on non-pathogenic bacteria support stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Hay, Jake J.; Rodrigo-Navarro, Aleixandre; Hassi, Karoliina; Moulisova, Vladimira; Dalby, Matthew J.; Salmeron-Sanchez, Manuel

    2016-02-01

    Lactococcus lactis, a non-pathogenic bacteria, has been genetically engineered to express the III7-10 fragment of human fibronectin as a membrane protein. The engineered L. lactis is able to develop biofilms on different surfaces (such as glass and synthetic polymers) and serves as a long-term substrate for mammalian cell culture, specifically human mesenchymal stem cells (hMSC). This system constitutes a living interface between biomaterials and stem cells. The engineered biofilms remain stable and viable for up to 28 days while the expressed fibronectin fragment induces hMSC adhesion. We have optimised conditions to allow long-term mammalian cell culture, and found that the biofilm is functionally equivalent to a fibronectin-coated surface in terms of osteoblastic differentiation using bone morphogenetic protein 2 (BMP-2) added to the medium. This living bacteria interface holds promise as a dynamic substrate for stem cell differentiation that can be further engineered to express other biochemical cues to control hMSC differentiation.

  19. Living biointerfaces based on non-pathogenic bacteria support stem cell differentiation

    PubMed Central

    Hay, Jake J.; Rodrigo-Navarro, Aleixandre; Hassi, Karoliina; Moulisova, Vladimira; Dalby, Matthew J.; Salmeron-Sanchez, Manuel

    2016-01-01

    Lactococcus lactis, a non-pathogenic bacteria, has been genetically engineered to express the III7–10 fragment of human fibronectin as a membrane protein. The engineered L. lactis is able to develop biofilms on different surfaces (such as glass and synthetic polymers) and serves as a long-term substrate for mammalian cell culture, specifically human mesenchymal stem cells (hMSC). This system constitutes a living interface between biomaterials and stem cells. The engineered biofilms remain stable and viable for up to 28 days while the expressed fibronectin fragment induces hMSC adhesion. We have optimised conditions to allow long-term mammalian cell culture, and found that the biofilm is functionally equivalent to a fibronectin-coated surface in terms of osteoblastic differentiation using bone morphogenetic protein 2 (BMP-2) added to the medium. This living bacteria interface holds promise as a dynamic substrate for stem cell differentiation that can be further engineered to express other biochemical cues to control hMSC differentiation. PMID:26902619

  20. Membrane-Targeting DCAP Analogues with Broad-Spectrum Antibiotic Activity against Pathogenic Bacteria.

    PubMed

    Hurley, Katherine A; Heinrich, Victoria A; Hershfield, Jeremy R; Demons, Samandra T; Weibel, Douglas B

    2015-04-01

    We performed a structure-activity relationship study of 2-((3-(3,6-dichloro-9H-carbazol-9-yl)-2-hydroxypropyl)amino)-2-(hydroxymethyl)propane-1,3-diol (DCAP), which is an antibacterial agent that disrupts the membrane potential and permeability of bacteria. The stereochemistry of DCAP had no effect on the biological activity of DCAP. The aromaticity and electronegativity of the chlorine-substituted carbazole was required for activity, suggesting that its planar and dipolar characteristics orient DCAP in membranes. Increasing the hydrophobicity of the tail region of DCAP enhanced its antibiotic activity. Two DCAP analogues displayed promising antibacterial activity against the BSL-3 pathogens Bacillus anthracis and Francisella tularensis. Codosing DCAP analogues with ampicillin or kanamycin increased their potency. These studies demonstrate that DCAP and its analogues may be a promising scaffold for developing chemotherapeutic agents that bind to bacterial membranes and kill strains of slow-growing or dormant bacteria that cause persistent infections. PMID:25941556

  1. Living biointerfaces based on non-pathogenic bacteria support stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Hay, Jake J.; Rodrigo-Navarro, Aleixandre; Hassi, Karoliina; Moulisova, Vladimira; Dalby, Matthew J.; Salmeron-Sanchez, Manuel

    2016-02-01

    Lactococcus lactis, a non-pathogenic bacteria, has been genetically engineered to express the III7–10 fragment of human fibronectin as a membrane protein. The engineered L. lactis is able to develop biofilms on different surfaces (such as glass and synthetic polymers) and serves as a long-term substrate for mammalian cell culture, specifically human mesenchymal stem cells (hMSC). This system constitutes a living interface between biomaterials and stem cells. The engineered biofilms remain stable and viable for up to 28 days while the expressed fibronectin fragment induces hMSC adhesion. We have optimised conditions to allow long-term mammalian cell culture, and found that the biofilm is functionally equivalent to a fibronectin-coated surface in terms of osteoblastic differentiation using bone morphogenetic protein 2 (BMP-2) added to the medium. This living bacteria interface holds promise as a dynamic substrate for stem cell differentiation that can be further engineered to express other biochemical cues to control hMSC differentiation.

  2. Antimicrobial activity of essential oil of Eucalyptus globulus against fish pathogenic bacteria

    PubMed Central

    Park, Joon-Woo; Wendt, Mitchell

    2016-01-01

    The antibacterial activities of the essential oil of Eucalyptus globulus (EOEG) was determined against 7 fish pathogenic bacteria (Edwardsiella tarda, Streptococcus iniae, S. parauberis, Lactococcus garviae, Vibrio harveyi, V. ichthyoenteri and Photobacterium damselae) obtained from farmed olive flounder. The inhibitory activity was evaluated by three methods: Disc diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). According to the disc diffusion test, as the concentration of EOEG (5-40 µg) rises, the inhibitory zone increases in size. Compared with amoxicillin, tetracycline and chloramphenicol, EOEG showed similar antibacterial activity. The MIC of EOEG ranged from 7.8 to 125 mg/mL and MBC values ranged from 62 to 250 mg/mL. These results show that EOEG has antimicrobial activity against all seven bacteria, but there was no marked difference between each genus. From these results, it is suggested that EOEG can be used as an antimicrobial agent against fish bacterial diseases in the fish industry. PMID:27382376

  3. Survival of Potentially Pathogenic Human-Associated Bacteria in the Rhizosphere of Hydroponically Grown Wheat

    NASA Technical Reports Server (NTRS)

    Morales, Anabelle; Garland, Jay L.; Lim, Daniel V.

    1996-01-01

    Plants may serve as reservoirs for human-associated bacteria (H-AB) in long-term space missions containing bioregenerative life support systems. The current study examined the abilities of five human-associated potential pathogens, Pseudomonas aeruginosa, Pseudomonas cepacia, Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli, to colonize and grow in the rhizosphere of hydroponically grown wheat, a candidate crop for life support. All of these bacteria have been recovered from past NASA missions and present potential problems for future missions. The abilities of these organisms to adhere to the roots of axenic five-day-old wheat (Triticum aestivum L. cv. Yecora rojo) were evaluated by enumeration of the attached organisms after a one hour incubation of roots in a suspension (approximately 10(exp 8 cu/ml)) of the H-AB. Results showed that a greater percentage of P. aeruginosa cells adhered to the wheat roots than the other four H-AB. Similarly incubated seedlings were also grown under attempted axenic conditions for seven days to examine the potential of each organism to proliferate in the rhizosphere (root colonization capacity). P. cepacia and P. aeruginosa showed considerable growth. E. coli and S. aureus showed no significant growth, and S. pyogenes died off in the wheat rhizosphere. Studies examining the effects of competition on the survival of these microorganisms indicated that P. aeruginosa was the only organism that survived in the rhizosphere of hydroponically grown wheat in the presence of different levels of microbial competition.

  4. Antimicrobial activity of essential oil of Eucalyptus globulus against fish pathogenic bacteria.

    PubMed

    Park, Joon-Woo; Wendt, Mitchell; Heo, Gang-Joon

    2016-06-01

    The antibacterial activities of the essential oil of Eucalyptus globulus (EOEG) was determined against 7 fish pathogenic bacteria (Edwardsiella tarda, Streptococcus iniae, S. parauberis, Lactococcus garviae, Vibrio harveyi, V. ichthyoenteri and Photobacterium damselae) obtained from farmed olive flounder. The inhibitory activity was evaluated by three methods: Disc diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). According to the disc diffusion test, as the concentration of EOEG (5-40 µg) rises, the inhibitory zone increases in size. Compared with amoxicillin, tetracycline and chloramphenicol, EOEG showed similar antibacterial activity. The MIC of EOEG ranged from 7.8 to 125 mg/mL and MBC values ranged from 62 to 250 mg/mL. These results show that EOEG has antimicrobial activity against all seven bacteria, but there was no marked difference between each genus. From these results, it is suggested that EOEG can be used as an antimicrobial agent against fish bacterial diseases in the fish industry. PMID:27382376

  5. Survival of potentially pathogenic human-associated bacteria in the rhizosphere of hydroponically grown wheat.

    PubMed

    Morales, A; Garland, J L; Lim, D V

    1996-07-01

    Plants may serve as reservoirs for human-associated bacteria (H-AB) in long-term space missions containing bioregenerative life support systems. The current study examined the abilities of five human-associated potential pathogens, Pseudomonas aeruginosa, Pseudomonas cepacia, Staphylococcus aureus, Streptococcus pyogenes and Escherichia coli, to colonize and grow in the rhizosphere of hydroponically grown wheat, a candidate crop for life support. All of these bacteria have been recovered from past NASA missions and present potential problems for future missions. The abilities of these organisms to adhere to the roots of axenic five-day-old wheat (Triticum aestivum L. cv. Yecora rojo) were evaluated by enumeration of the attached organisms after a one hour incubation of roots in a suspension (approximately 10(8) cfu ml-1) of the H-AB. Results showed that a greater percentage of P. aeruginosa cells adhered to the wheat roots than the other four H-AB. Similarly incubated seedlings were also grown under attempted axenic conditions for seven days to examine the potential of each organism to proliferate in the rhizosphere (root colonization capacity). P. cepacia and P. aerogiunosa showed considerable growth, E. coli and S. aureus showed no significant growth, and S. pyogenes died off in the wheat rhizosphere. Studies examining the effects of competition on the survival of these microorganisms indicated that P. aeruginosa was the only organism that survived in the rhizosphere of hydroponically grown wheat in the presence of different levels of microbial competition.

  6. Long-Term Survival of Pathogenic and Sanitation Indicator Bacteria in Experimental Biowaste Composts

    PubMed Central

    Lemunier, Mélanie; Francou, Cédric; Rousseaux, Sandrine; Houot, Sabine; Dantigny, Philippe; Piveteau, Pascal; Guzzo, Jean

    2005-01-01

    For economic, agricultural, and environmental reasons, composting is frequently used for organic waste recycling. One approach to limiting the potential risk from bacterial food-borne illnesses is to ensure that soil amendments and organic fertilizers are disinfected. However, more knowledge concerning the microbiological safety of composted substrates other than sludge and manure is necessary. Experimental in-vessel biowaste composts were used to study the survival of seeded Listeria monocytogenes, Salmonella enterica subsp. enterica serotype Enteritidis, and Escherichia coli. Four organic waste mixtures, containing various proportions of paper and cardboard, fruits and vegetables, and green waste, were composted in laboratory reactors with forced aeration. The physicochemical and microbiological parameters were monitored for 12 weeks during composting. The survival of bacteria over a 3-month period at 25°C was assessed with samples collected after different experimental composting times. Strain survival was also monitored in mature sterilized composts. Nonsterile composts did not support pathogen growth, but survival of seeded pathogens was observed. Salmonella serovar Enteritidis survived in all composts, and longer survival (3 months) was observed in mature composts (8 and 12 weeks of composting). Mature biowaste composts may support long-term survival of Salmonella serovar Enteritidis during storage at room temperature. E. coli and L. monocytogenes survival was observed only in 4-week-old composts and never in older composts. Proper composting may prevent long-term survival of E. coli and L. monocytogenes. These results suggest that like composted sewage sludge or manure, domestic waste composts may support pathogen survival. Survival was not related to the physicochemical characteristics of the composts. PMID:16204488

  7. Antimicrobial Activity of Croton macrostachyus Stem Bark Extracts against Several Human Pathogenic Bacteria

    PubMed Central

    Obey, Jackie K.; von Wright, Atte; Orjala, Jimmy; Kauhanen, Jussi; Tikkanen-Kaukanen, Carina

    2016-01-01

    In Kenya, leaves and roots from Croton macrostachyus are used as a traditional medicine for infectious diseases such as typhoid and measles, but reports on possible antimicrobial activity of stem bark do not exist. In this study, the antibacterial and antifungal effects of methanol, ethyl acetate and butanol extracts, and purified lupeol of C. macrostachyus stem bark were determined against important human gram-negative pathogens Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, and Enterobacter aerogenes, gram-positive Listeria monocytogenes, and a fungus Candida albicans. The most promising broad scale antimicrobial activity against all the studied pathogens was shown by the ethyl acetate extract. The ethyl acetate extract induced the zone of inhibition between 10.1 ± 0.6 mm and 16.0 ± 1.2 mm against S. typhi, E. coli, K. pneumoniae, E. aerogenes, and L. monocytogenes with weaker antimicrobial activity against C. albicans (zone of inhibition: 5.6 ± 1.0 mm). The antibiotic controls (amoxicillin, ciprofloxacin, ampicillin, benzylpenicillin, clotrimazole, and cefotaxime) showed antimicrobial activity with zones of inhibition within 13.4 ± 0.7–22.1 ± 0.9 mm. The ethyl acetate extract had MIC in the range of 125–250 mg/mL against all the studied bacteria and against C. albicans MIC was 500 mg/mL. The present results give scientific evidence and support the traditional use of C. macrostachyus stem bark as a source for antimicrobials. We show that C. macrostachyus stem bark lupeol is a promising antimicrobial agent against several important human pathogens. PMID:27293897

  8. Potentially Pathogenic Bacteria in Shower Water and Air of a Stem Cell Transplant Unit▿

    PubMed Central

    Perkins, Sarah D.; Mayfield, Jennie; Fraser, Victoria; Angenent, Largus T.

    2009-01-01

    Potential pathogens from shower water and aerosolized shower mist (i.e., shower aerosol) have been suggested as an environmental source of infection for immunocompromised patients. To quantify the microbial load in shower water and aerosol samples, we used culture, microscopic, and quantitative PCR methods to investigate four shower stalls in a stem cell transplant unit at Barnes-Jewish Hospital in St. Louis, MO. We also tested membrane-integrated showerheads as a possible mitigation strategy. In addition to quantification, a 16S rRNA gene sequencing survey was used to characterize the abundant bacterial populations within shower water and aerosols. The average total bacterial counts were 2.2 × 107 cells/liter in shower water and 3.4 × 104 cells/m3 in shower aerosol, and these counts were reduced to 6.3 × 104 cells/liter (99.6% efficiency) and 8.9 × 103 cells/m3 (82.4% efficiency), respectively, after membrane-integrated showerheads were installed. Potentially pathogenic organisms were found in both water and aerosol samples from the conventional showers. Most notable was the presence of Mycobacterium mucogenicum (99.5% identity) in the water and Pseudomonas aeruginosa (99.3% identity) in the aerosol samples. Membrane-integrated showerheads may protect immunocompromised patients from waterborne infections in a stem cell transplant unit because of efficient capture of vast numbers of potentially pathogenic bacteria from hospital water. However, an in-depth epidemiological study is necessary to investigate whether membrane-integrated showerheads reduce hospital-acquired infections. The microbial load in shower aerosols with conventional showerheads was elevated compared to the load in HEPA-filtered background air in the stem cell unit, but it was considerably lower than typical indoor air. Thus, in shower environments without HEPA filtration, the increase in microbial load due to shower water aerosolization would not have been distinguishable from anticipated

  9. Antimicrobial Activity of Croton macrostachyus Stem Bark Extracts against Several Human Pathogenic Bacteria.

    PubMed

    Obey, Jackie K; von Wright, Atte; Orjala, Jimmy; Kauhanen, Jussi; Tikkanen-Kaukanen, Carina

    2016-01-01

    In Kenya, leaves and roots from Croton macrostachyus are used as a traditional medicine for infectious diseases such as typhoid and measles, but reports on possible antimicrobial activity of stem bark do not exist. In this study, the antibacterial and antifungal effects of methanol, ethyl acetate and butanol extracts, and purified lupeol of C. macrostachyus stem bark were determined against important human gram-negative pathogens Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, and Enterobacter aerogenes, gram-positive Listeria monocytogenes, and a fungus Candida albicans. The most promising broad scale antimicrobial activity against all the studied pathogens was shown by the ethyl acetate extract. The ethyl acetate extract induced the zone of inhibition between 10.1 ± 0.6 mm and 16.0 ± 1.2 mm against S. typhi, E. coli, K. pneumoniae, E. aerogenes, and L. monocytogenes with weaker antimicrobial activity against C. albicans (zone of inhibition: 5.6 ± 1.0 mm). The antibiotic controls (amoxicillin, ciprofloxacin, ampicillin, benzylpenicillin, clotrimazole, and cefotaxime) showed antimicrobial activity with zones of inhibition within 13.4 ± 0.7-22.1 ± 0.9 mm. The ethyl acetate extract had MIC in the range of 125-250 mg/mL against all the studied bacteria and against C. albicans MIC was 500 mg/mL. The present results give scientific evidence and support the traditional use of C. macrostachyus stem bark as a source for antimicrobials. We show that C. macrostachyus stem bark lupeol is a promising antimicrobial agent against several important human pathogens.

  10. Ecological and aromatic impact of two Gram-negative bacteria (Psychrobacter celer and Hafnia alvei) inoculated as part of the whole microbial community of an experimental smear soft cheese.

    PubMed

    Irlinger, Françoise; Yung, Stéphane Ah Yuen In; Sarthou, Anne-Sophie; Delbès-Paus, Céline; Montel, Marie-Christine; Coton, Emmanuel; Coton, Monika; Helinck, Sandra

    2012-02-15

    The impact of the growth of two Gram-negative bacteria, Psychrobacter celer and Hafnia alvei, inoculated at 10(2) and 10(6) cfu/g, on the dynamics of a multispecies community as well as on volatile aroma compound production during cheese ripening was investigated. Results showed that P. celer was able to successfully implant itself in cheese, regardless of its inoculation level. However, when it was inoculated at a high level, the bacterial biodiversity was drastically lowered from day 25 to the end of ripening. Overall, the presence of P. celer led to the higher production of volatile aroma compounds such as aldehydes, ketones and sulfur compounds. Regardless of its inoculation level, H. alvei barely affected the growth of the bacterial community and was subdominant at the end of ripening. It influenced total volatile aroma compound production with volatile sulfur compounds being the most abundant. Overall, these two bacteria were able to implant themselves in a cheese community and significantly contributed to the aromatic properties of the cheese. Their role in flavoring and their interactions with the technological microorganisms must be considered during cheese ripening and should be further investigated.

  11. Ecological and aromatic impact of two Gram-negative bacteria (Psychrobacter celer and Hafnia alvei) inoculated as part of the whole microbial community of an experimental smear soft cheese.

    PubMed

    Irlinger, Françoise; Yung, Stéphane Ah Yuen In; Sarthou, Anne-Sophie; Delbès-Paus, Céline; Montel, Marie-Christine; Coton, Emmanuel; Coton, Monika; Helinck, Sandra

    2012-02-15

    The impact of the growth of two Gram-negative bacteria, Psychrobacter celer and Hafnia alvei, inoculated at 10(2) and 10(6) cfu/g, on the dynamics of a multispecies community as well as on volatile aroma compound production during cheese ripening was investigated. Results showed that P. celer was able to successfully implant itself in cheese, regardless of its inoculation level. However, when it was inoculated at a high level, the bacterial biodiversity was drastically lowered from day 25 to the end of ripening. Overall, the presence of P. celer led to the higher production of volatile aroma compounds such as aldehydes, ketones and sulfur compounds. Regardless of its inoculation level, H. alvei barely affected the growth of the bacterial community and was subdominant at the end of ripening. It influenced total volatile aroma compound production with volatile sulfur compounds being the most abundant. Overall, these two bacteria were able to implant themselves in a cheese community and significantly contributed to the aromatic properties of the cheese. Their role in flavoring and their interactions with the technological microorganisms must be considered during cheese ripening and should be further investigated. PMID:22177851

  12. Bactericidal efficacy of elevated pH on fish pathogenic and environmental bacteria

    USGS Publications Warehouse

    Starliper, Clifford E.; Watten, Barnaby J.

    2013-01-01

    Ship ballast water is a recognized medium for transfer and introductions of nonindigenous species. There is a need for new ballast water treatment methods that effectively and safely eliminate or greatly minimize movements of these species. The present study employed laboratory methods to evaluate the bactericidal efficacy of increased pH (pH 10.0–12.0) for exposure durations of up to 72 h to kill a variety of Gram-negative and Gram-positive bacteria including fish pathogens (Aeromonas spp., Yersinia ruckeri, Edwardsiella ictaluri, Serratia liquefaciens, Carnobacterium sp.), other common aquatic-inhabitant bacteria (Serratia marcescens, Pseudomonas fluorescens, Staphylococcus sp., Bacillus sp.) and indicators listed in International Maritime Organization D2 Standards; namely, Vibrio cholera (an environmental isolate from fish), Escherichia coli and Enterococcus faecalis. Volumes of 5 N NaOH were added to tryptic soy broth to obtain desired pH adjustments. Viable cells were determined after 0, 4, 12, 24, 48, and 72 h. Initial (0 h) cell numbers ranged from 3.40 × 104 cfu/mL for Bacillus sp. to 2.44 × 107 cfu/mL for E. faecalis. The effective endpoints of pH and treatment duration necessary to realize 100% bactericidal effect varied; however, all bacteria tested were killed within 72 h at pH 12.0 or lower. The lowest parameters examined, 4 h at pH 10.0, were bactericidal to V. cholera, E. ictaluri, three of four isolates of E. coli, and (three of four) Aeromonas salmonicida subsp. salmonicida. Bactericidal effect was attained at pH 10.0 within 12 h for the other A. salmonicida subsp. salmonicida, and within 24 h for P. fluorescens, and the remaining E. coli.

  13. [A new method for evaluation of the antagonistic action of bacterial lactic acid (LAB) on selected pathogenic indicator bacteria].

    PubMed

    Strus, M

    1998-01-01

    A comparison was made of three methods: paper disc, double layer and a newly proposed agar slab techniques for testing antibacterial activity of Lactobacillus strains. Strains of indicator bacteria were selected from important pathogens of the human alimentary and genitourinary tract. The agar slab method, which is based on applying of slabs of MRS agar with overnight growth of the antagonistic bacteria to the surface of appropriate agar plates seeded with indicator bacteria, appeared to be the only method suitable for testing of aerobic and anaerobic fastidious bacteria. After testing of 27 Lactobacillus strains against 3 selected indicator bacteria: E. coli, Salmonella enteritidis and Staphylococcus aureus, calculating mean values and standard deviations for diameters of inhibitory zones and making variance analysis it was shown that in comparison to other methods the agar slab technique, although less sensitive than others, gave most consistent and reproducible results.

  14. Occurrence and distribution of fecal indicator bacteria and gene markers of pathogenic bacteria in Great Lakes tributaries, March-October 2011

    USGS Publications Warehouse

    Brennan, Angela K.; Johnson, Heather E.; Totten, Alexander R.; Duris, Joseph W.

    2015-01-01

    Water samples were analyzed for the presence of FIB concentrations (FIB; fecal coliform bacteria, Escherichia coli [E. coli], and enterococci) by using membrane filtration and serial dilution methods. The resulting enrichments from standard culturing of the samples were then analyzed by using polymerase chain reaction (PCR) to determine the occurrence of pathogen gene markers for Shigella species, Campylobacter jejuni and coli, Salmonellaspecies, and pathogenic E. coli, including Shiga toxin-producing E. coli (STEC).

  15. Rapidly evolving genes in pathogens: methods for detecting positive selection and examples among fungi, bacteria, viruses and protists.

    PubMed

    Aguileta, Gabriela; Refrégier, Guislaine; Yockteng, Roxana; Fournier, Elisabeth; Giraud, Tatiana

    2009-07-01

    The ongoing coevolutionary struggle between hosts and pathogens, with hosts evolving to escape pathogen infection and pathogens evolving to escape host defences, can generate an 'arms race', i.e., the occurrence of recurrent selective sweeps that each favours a novel resistance or virulence allele that goes to fixation. Host-pathogen coevolution can alternatively lead to a 'trench warfare', i.e., balancing selection, maintaining certain alleles at loci involved in host-pathogen recognition over long time scales. Recently, technological and methodological progress has enabled detection of footprints of selection directly on genes, which can provide useful insights into the processes of coevolution. This knowledge can also have practical applications, for instance development of vaccines or drugs. Here we review the methods for detecting genes under positive selection using divergence data (i.e., the ratio of nonsynonymous to synonymous substitution rates, d(N)/d(S)). We also review methods for detecting selection using polymorphisms, such as methods based on F(ST) measures, frequency spectrum, linkage disequilibrium and haplotype structure. In the second part, we review examples where targets of selection have been identified in pathogens using these tests. Genes under positive selection in pathogens have mostly been sought among viruses, bacteria and protists, because of their paramount importance for human health. Another focus is on fungal pathogens owing to their agronomic importance. We finally discuss promising directions in pathogen studies, such as detecting selection in non-coding regions.

  16. Use of Extract of Citrus sinensis as an antimicrobial agent for foodborne zoonotic pathogens and spoilage bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne pathogens remain global health problems despite concerted efforts to control the transmission of these microorganisms through food. The resurgence of drug resistant bacteria has renewed interest in developing and testing new sources of antimicrobial agents to control foodborne illness. Thi...

  17. Cultivation and qPCR detection of pathogenic and antibiotic resistant bacteria establishment in naive broiler houses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    : Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space, atop bedding material such as pine shavings or rice hulls, for approximately 6.5 weeks. This environment is known for harboring pathogens and antibiotic resistant bacteria, but ...

  18. Different routes of inoculation impact infectivity and pathogenesis of H5N1 high pathogenicity avian influenza virus infection in chickens and domestic ducks.

    PubMed

    Kwon, Y K; Swayne, D E

    2010-12-01

    The H5N1 type A influenza viruses classified as Qinghai-like virus (clade 2.2) are a unique lineage of type A influenza viruses with the capacity to produce significant disease and mortality in gallinaceous and anseriform birds, including domestic and wild ducks. The objective of this study was to determine the susceptibility and pathogenesis of chickens and domestic ducks to A/Whooper Swan/Mongolia/224/05 (H5N1) high pathogenicity avian influenza (HPAI) virus when administered through respiratory or alimentary routes of exposure. The chickens and ducks were more susceptible to the H5N1 HPAI virus, as evidenced by low infectious and lethal viral doses, when exposed by intranasal as compared to alimentary routes of inoculation (intragastric or oral-fed infected chicken meat). In the alimentary exposure pathogenesis study, pathologic changes included hemorrhage, necrosis, and inflammation in association with virus detection. These changes were generally observed in most of the visceral organs of chickens, between 2 and 4 days postinoculation (DPI), and are similar to lesions and virus localization seen in birds in natural cases or in experimental studies using the intranasal route. Alimentary exposure to the virus caused systemic infection in the ducks, characterized by moderate lymphocytic encephalitis, necrotized hepatitis, and pancreatitis with a corresponding demonstration of virus within the lesions. In both chickens and ducks with alimentary exposure, lesions, virus, or both were first demonstrated in the upper alimentary tract on 1 DPI, suggesting that the alimentary tract was the initial site affected upon consumption of infected meat or on gavage of virus in liquid medium. However, as demonstrated in the infectivity study in chickens, alimentary infection required higher exposure doses to produce infection as compared to intranasal exposure in chickens. These data suggest that upper respiratory exposure to H5N1 HPAI virus in birds is more likely to result in

  19. Changes in Aerobic Plate and Escherichia coli-Coliform Counts and in Populations of Inoculated Foodborne Pathogens on Inshell Walnuts during Storage.

    PubMed

    Frelka, John C; Davidson, Gordon R; Harris, Linda J

    2016-07-01

    After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli?coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P > 0.05) or decreased by <0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (∼8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of -0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by -0.17 log CFU per nut per month and -0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent

  20. Changes in Aerobic Plate and Escherichia coli-Coliform Counts and in Populations of Inoculated Foodborne Pathogens on Inshell Walnuts during Storage.

    PubMed

    Frelka, John C; Davidson, Gordon R; Harris, Linda J

    2016-07-01

    After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli?coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P > 0.05) or decreased by <0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (∼8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of -0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by -0.17 log CFU per nut per month and -0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent

  1. Influence of river discharge on abundance and dissemination of heterotrophic, indicator and pathogenic bacteria along the East Coast of India.

    PubMed

    Prasad, V R; Srinivas, T N R; Sarma, V V S S

    2015-06-15

    In order to examine the influence of discharge from different rivers from peninsular India and urban sewage on intensity and dissemination of heterotrophic, indicator and pathogenic bacteria, a study was carried out during peak discharge period along coastal Bay of Bengal. The coastal Bay received freshwater inputs from the river Ganges while Godavari and Krishna contributed to the south. Contrasting difference in salinity, temperature, nutrients and organic matter was observed between north and south east coast of India. The highest heterotrophic, indicator and pathogenic bacterial abundance was observed in the central coastal Bay that received urban sewage from the major city. Intensity and dissemination of heterotrophic, indicator and pathogenic bacteria displayed linear relation with magnitude of discharge. The coliform load was observed up to 100km from the coast suggesting that marine waters were polluted during the monsoon season and its impact on the ecosystem needs further studies. PMID:25934433

  2. Single Walled Carbon Nanotube-Based Electrical Biosensor for the Label-Free Detection of Pathogenic Bacteria.

    PubMed

    Yoo, Seung Min; Baek, Youn-Kyoung; Shin, SunHaeRa; Kim, Ju-Hyun; Jung, Hee-Tae; Choi, Yang-Kyu; Lee, Sang Yup

    2016-06-01

    We herein describe the development of a single-walled carbon nanotube (SWNT)-based electrical biosensor consisting of a two-terminal resistor, and report its use for the specific, label-free detection of pathogenic bacteria via changes in conductance. The ability of this biosensor to recognize different pathogenic bacteria was analyzed, and conditions were optimized with different probe concentrations. Using this system, the reference strains and clinical isolates of Staphylococcus aureus and Escherichia coli were successfully detected; in both cases, the sensor showed a detection limit of 10 CFU. This SWNT-based electrical biosensor will prove useful for the development of highly sensitive and specific handheld pathogen detectors. PMID:27427746

  3. The Anti-HIV Microbicide Candidate RC-101 Inhibits Pathogenic Vaginal Bacteria Without Harming Endogenous Flora or Mucosa

    PubMed Central

    Eade, Colleen R.; Cole, Amy L.; Diaz, Camila; Rohan, Lisa C.; Parniak, Michael A.; Marx, Preston; Tarwater, Patrick M.; Gupta, Phalguni; Cole, Alexander M.

    2012-01-01

    Problem Vaginal microbicides represent a promising approach for preventing heterosexual HIV transmission. However, preclinical evaluation should be conducted to ensure that microbicides will be safe for human cells and healthy microflora of the female reproductive tract. One microbicide candidate, RC-101, has been effective and well-tolerated in preliminary cell culture and macaque models. However, the effect of RC-101 on primary vaginal tissues and resident vaginal microflora requires further evaluation. Method of Study We treated primary vaginal tissues and vaginal bacteria, both pathogenic and commensal, with RC-101 to investigate effects of this microbicide. Results RC-101 was well-tolerated by host tissues, and also by commensal vaginal bacteria. Simultaneously, pathogenic vaginal bacteria, which are known to increase susceptibility to HIV acquisition, were inhibited by RC-101. Conclusions By establishing vaginal microflora, the specific antibacterial activity of RC-101 may provide a dual mechanism of HIV protection. These findings support advancement of RC-101 to clinical trials. PMID:23167830

  4. Effects of the Essential Oil from Origanum vulgare L. on Survival of Pathogenic Bacteria and Starter Lactic Acid Bacteria in Semihard Cheese Broth and Slurry.

    PubMed

    de Souza, Geany Targino; de Carvalho, Rayssa Julliane; de Sousa, Jossana Pereira; Tavares, Josean Fechine; Schaffner, Donald; de Souza, Evandro Leite; Magnani, Marciane

    2016-02-01

    This study assessed the inhibitory effects of the essential oil from Origanum vulgare L. (OVEO) on Staphylococcus aureus, Listeria monocytogenes, and a mesophilic starter coculture composed of lactic acid bacteria (Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris) in Brazilian coalho cheese systems. The MIC of OVEO was 2.5 μl/ml against both S. aureus and L. monocytogenes and 0.6 μl/ml against the tested starter coculture. In cheese broth containing OVEO at 0.6 μl/ml, no decrease in viable cell counts (VCC) of both pathogenic bacteria was observed, whereas the initial VCC of the starter coculture decreased approximately 1.0 log CFU/ml after 24 h of exposure at 10°C. OVEO at 1.25 and 2.5 μl/ml caused reductions of up to 2.0 and 2.5 log CFU/ml in S. aureus and L. monocytogenes, respectively, after 24 h of exposure in cheese broth. At these same concentrations, OVEO caused a greater decrease of initial VCC of the starter coculture following 4 h of exposure. Higher concentrations of OVEO were required to decrease the VCC of all target bacteria in semisolid coalho cheese slurry compared with cheese broth. The VCC of Lactococcus spp. in coalho cheese slurry containing OVEO were always lower than those of pathogenic bacteria under the same conditions. These results suggest that the concentrations of OVEO used to control pathogenic bacteria in semihard cheese should be carefully evaluated because of its inhibitory effects on the growth of starter lactic acid cultures used during the production of the product.

  5. Effects of the Essential Oil from Origanum vulgare L. on Survival of Pathogenic Bacteria and Starter Lactic Acid Bacteria in Semihard Cheese Broth and Slurry.

    PubMed

    de Souza, Geany Targino; de Carvalho, Rayssa Julliane; de Sousa, Jossana Pereira; Tavares, Josean Fechine; Schaffner, Donald; de Souza, Evandro Leite; Magnani, Marciane

    2016-02-01

    This study assessed the inhibitory effects of the essential oil from Origanum vulgare L. (OVEO) on Staphylococcus aureus, Listeria monocytogenes, and a mesophilic starter coculture composed of lactic acid bacteria (Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris) in Brazilian coalho cheese systems. The MIC of OVEO was 2.5 μl/ml against both S. aureus and L. monocytogenes and 0.6 μl/ml against the tested starter coculture. In cheese broth containing OVEO at 0.6 μl/ml, no decrease in viable cell counts (VCC) of both pathogenic bacteria was observed, whereas the initial VCC of the starter coculture decreased approximately 1.0 log CFU/ml after 24 h of exposure at 10°C. OVEO at 1.25 and 2.5 μl/ml caused reductions of up to 2.0 and 2.5 log CFU/ml in S. aureus and L. monocytogenes, respectively, after 24 h of exposure in cheese broth. At these same concentrations, OVEO caused a greater decrease of initial VCC of the starter coculture following 4 h of exposure. Higher concentrations of OVEO were required to decrease the VCC of all target bacteria in semisolid coalho cheese slurry compared with cheese broth. The VCC of Lactococcus spp. in coalho cheese slurry containing OVEO were always lower than those of pathogenic bacteria under the same conditions. These results suggest that the concentrations of OVEO used to control pathogenic bacteria in semihard cheese should be carefully evaluated because of its inhibitory effects on the growth of starter lactic acid cultures used during the production of the product. PMID:26818985

  6. Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools.

    PubMed

    Bittar, Fadi; Keita, Mamadou B; Lagier, Jean-Christophe; Peeters, Martine; Delaporte, Eric; Raoult, Didier

    2014-11-24

    Wild apes are considered to be the most serious reservoir and source of zoonoses. However, little data are available about the gut microbiota and pathogenic bacteria in gorillas. For this propose, a total of 48 fecal samples obtained from 21 Gorilla gorilla gorilla individuals (as revealed via microsatellite analysis) were screened for human bacterial pathogens using culturomics and molecular techniques. By applying culturomics to one index gorilla and using specific media supplemented by plants, we tested 12,800 colonies and identified 147 different bacterial species, including 5 new species. Many opportunistic pathogens were isolated, including 8 frequently associated with human diseases; Mycobacterium bolletii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Staphylococcus aureus and Clostridium botulinum. The genus Treponema accounted for 27.4% of the total reads identified at the genus level via 454 pyrosequencing. Using specific real-time PCR on 48 gorilla fecal samples, in addition to classical human pathogens, we also observed the fastidious bacteria Bartonella spp. Borrelia spp., Coxiella burnetii and Tropheryma whipplei in the gorilla population. We estimated that the prevalence of these pathogens vary between 4.76% and 85.7%. Therefore, gorillas share many bacterial pathogens with humans suggesting that they could be a reservoir for their emergence.

  7. Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools

    PubMed Central

    Bittar, Fadi; Keita, Mamadou B.; Lagier, Jean-Christophe; Peeters, Martine; Delaporte, Eric; Raoult, Didier

    2014-01-01

    Wild apes are considered to be the most serious reservoir and source of zoonoses. However, little data are available about the gut microbiota and pathogenic bacteria in gorillas. For this propose, a total of 48 fecal samples obtained from 21 Gorilla gorilla gorilla individuals (as revealed via microsatellite analysis) were screened for human bacterial pathogens using culturomics and molecular techniques. By applying culturomics to one index gorilla and using specific media supplemented by plants, we tested 12,800 colonies and identified 147 different bacterial species, including 5 new species. Many opportunistic pathogens were isolated, including 8 frequently associated with human diseases; Mycobacterium bolletii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Staphylococcus aureus and Clostridium botulinum. The genus Treponema accounted for 27.4% of the total reads identified at the genus level via 454 pyrosequencing. Using specific real-time PCR on 48 gorilla fecal samples, in addition to classical human pathogens, we also observed the fastidious bacteria Bartonella spp. Borrelia spp., Coxiella burnetii and Tropheryma whipplei in the gorilla population. We estimated that the prevalence of these pathogens vary between 4.76% and 85.7%. Therefore, gorillas share many bacterial pathogens with humans suggesting that they could be a reservoir for their emergence. PMID:25417711

  8. Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

    PubMed

    Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

    2016-11-01

    Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

  9. High-throughput DNA microarray detection of pathogenic bacteria in shallow well groundwater in the Kathmandu Valley, Nepal.

    PubMed

    Inoue, Daisuke; Hinoura, Takuji; Suzuki, Noriko; Pang, Junqin; Malla, Rabin; Shrestha, Sadhana; Chapagain, Saroj Kumar; Matsuzawa, Hiroaki; Nakamura, Takashi; Tanaka, Yasuhiro; Ike, Michihiko; Nishida, Kei; Sei, Kazunari

    2015-01-01

    Because of heavy dependence on groundwater for drinking water and other domestic use, microbial contamination of groundwater is a serious problem in the Kathmandu Valley, Nepal. This study investigated comprehensively the occurrence of pathogenic bacteria in shallow well groundwater in the Kathmandu Valley by applying DNA microarray analysis targeting 941 pathogenic bacterial species/groups. Water quality measurements found significant coliform (fecal) contamination in 10 of the 11 investigated groundwater samples and significant nitrogen contamination in some samples. The results of DNA microarray analysis revealed the presence of 1-37 pathogen species/groups, including 1-27 biosafety level 2 ones, in 9 of the 11 groundwater samples. While the detected pathogens included several feces- and animal-related ones, those belonging to Legionella and Arthrobacter, which were considered not to be directly associated with feces, were detected prevalently. This study could provide a rough picture of overall pathogenic bacterial contamination in the Kathmandu Valley, and demonstrated the usefulness of DNA microarray analysis as a comprehensive screening tool of a wide variety of pathogenic bacteria.

  10. Fighting Off Wound Pathogens in Horses with Honeybee Lactic Acid Bacteria.

    PubMed

    Olofsson, Tobias C; Butler, Éile; Lindholm, Christina; Nilson, Bo; Michanek, Per; Vásquez, Alejandra

    2016-10-01

    In the global perspective of antibiotic resistance, it is urgent to find potent topical antibiotics for the use in human and animal infection. Healing of equine wounds, particularly in the limbs, is difficult due to hydrostatic factors and exposure to environmental contaminants, which can lead to heavy bio-burden/biofilm formation and sometimes to infection. Therefore, antibiotics are often prescribed. Recent studies have shown that honeybee-specific lactic acid bacteria (LAB), involved in honey production, and inhibit human wound pathogens. The aim of this pilot study was to investigate the effects on the healing of hard-to-heal equine wounds after treatment with these LAB symbionts viable in a heather honey formulation. For this, we included ten horses with wound duration of >1 year, investigated the wound microbiota, and treated wounds with the novel honeybee LAB formulation. We identified the microbiota using MALDI-TOF mass spectrometry and DNA sequencing. In addition, the antimicrobial properties of the honeybee LAB formulation were tested against all wound isolates in vitro. Our results indicate a diverse wound microbiota including fifty-three bacterial species that showed 90 % colonization by at least one species of Staphylococcus. Treatment with the formulation promoted wound healing in all cases already after the first application and the wounds were either completely healed (n = 3) in less than 20 days or healing was in progress. Furthermore, the honeybee LAB formulation inhibited all pathogens when tested in vitro. Consequently, this new treatment option presents as a powerful candidate for the topical treatment of hard-to-heal wounds in horses. PMID:27324340

  11. Fighting Off Wound Pathogens in Horses with Honeybee Lactic Acid Bacteria.

    PubMed

    Olofsson, Tobias C; Butler, Éile; Lindholm, Christina; Nilson, Bo; Michanek, Per; Vásquez, Alejandra

    2016-10-01

    In the global perspective of antibiotic resistance, it is urgent to find potent topical antibiotics for the use in human and animal infection. Healing of equine wounds, particularly in the limbs, is difficult due to hydrostatic factors and exposure to environmental contaminants, which can lead to heavy bio-burden/biofilm formation and sometimes to infection. Therefore, antibiotics are often prescribed. Recent studies have shown that honeybee-specific lactic acid bacteria (LAB), involved in honey production, and inhibit human wound pathogens. The aim of this pilot study was to investigate the effects on the healing of hard-to-heal equine wounds after treatment with these LAB symbionts viable in a heather honey formulation. For this, we included ten horses with wound duration of >1 year, investigated the wound microbiota, and treated wounds with the novel honeybee LAB formulation. We identified the microbiota using MALDI-TOF mass spectrometry and DNA sequencing. In addition, the antimicrobial properties of the honeybee LAB formulation were tested against all wound isolates in vitro. Our results indicate a diverse wound microbiota including fifty-three bacterial species that showed 90 % colonization by at least one species of Staphylococcus. Treatment with the formulation promoted wound healing in all cases already after the first application and the wounds were either completely healed (n = 3) in less than 20 days or healing was in progress. Furthermore, the honeybee LAB formulation inhibited all pathogens when tested in vitro. Consequently, this new treatment option presents as a powerful candidate for the topical treatment of hard-to-heal wounds in horses.

  12. Antibacterial Activities of Metabolites from Platanus occidentalis (American sycamore) against Fish Pathogenic Bacteria

    PubMed Central

    Schrader, Kevin K; Hamann, Mark T; McChesney, James D; Rodenburg, Douglas L; Ibrahim, Mohamed A

    2016-01-01

    One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentally safe natural compounds as alternatives to antibiotics would benefit the aquaculture industries. Four natural compounds, commonly called platanosides, [kaempferol 3-O-α-L-(2″,3″-di-E-p-coumaroyl)rhamnoside (1), kaempferol 3-O-α-L-(2″-E-p-coumaroyl-3″-Z-p-coumaroyl)rhamnoside (2), kaempferol 3-O-α-L-(2″-Z-p-coumaroyl-3″-E-p-coumaroyl)rhamnoside (3), and kaempferol 3-O-α-L-(2″,3″-di-Z-p-coumaroyl)rhamnoside (4)] isolated from the leaves of the American sycamore (Platanus occidentalis) tree were evaluated using a rapid bioassay for their antibacterial activities against common fish pathogenic bacteria including Flavobacterium columnare, Edwardsiella ictaluri, Aeromonas hydrophila, and Streptococcus iniae. The four isomers and a mixture of all four isomers were strongly antibacterial against isolates of F. columnare and S. iniae. Against F. columnare ALM-00-173, 3 and 4 showed the strongest antibacterial activities, with 24-h 50% inhibition concentration (IC50) values of 2.13 ± 0.11 and 2.62 ± 0.23 mg/L, respectively. Against S. iniae LA94-426, 4 had the strongest antibacterial activity, with 24-h IC50 of 1.87 ± 0.23 mg/L. Neither a mixture of the isomers nor any of the individual isomers were antibacterial against isolates of E. ictaluri and A. hydrophila at the test concentrations used in the study. Several of the isomers appear promising for the potential management of columnaris disease and streptococcosis in fish.

  13. Phytochemical, toxicological and antimicrobial evaluation of lawsonia inermis extracts against clinical isolates of pathogenic bacteria

    PubMed Central

    2013-01-01

    Background The emerging resistance of pathogen against the currently available antimicrobial agents demands the search of new antimicrobial agents. The use of medicinal plants as natural substitute is the paramount area of research to overwhelm the drug resistance of infectious agents. Scientists have not made enough effort on the evaluation of safety of medicinal plant yet. Methods In the present study antimicrobial activity of Lawsonia inermis is investigated against clinical isolates of seven bacteria including four Gram negative (Escherichia coli, Salmonella typhi, Klebsiella spp., Shigella sonnei) and three Gram positive (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis) using disc diffusion method. Four types of Lawsonia inermis extracts were prepared using methanol, chloroform, acetone and water as extraction solvents, while DMSO (Dimethyl sulfoxide) and water as dissolution solvents. The rate and extent of bacterial killing was estimated by time-kill kinetic assay at 1× MIC of each bacterial isolate. The overall safety of Lawsonia inermis extracts was assessed in mice. Results Lawsonia inermis displayed noteworthy antimicrobial activity against both gram positive and gram negative bacterial strains used in the study. The minimum value of MIC for different bacterial strains ranged from 2.31 mg/ml to 9.27 mg/ml. At 1x MIC of each bacterial isolate, 3log10 decrease in CFU was recorded after 6 hours of drug exposure and no growth was observed in almost all tested bacteria after 24 hours of exposure. No sign of toxidrome were observed during in vivo toxicity evaluation in mice at 300 mg/kg concentration. Conclusion In conclusion, the present study provides the scientific rational for medicinal use of Lawsonia inermis. The use of Lawsonia inermis extracts is of great significance as substitute antimicrobial agent in therapeutics. PMID:24289297

  14. Selected Pathogens of Concern to Industrial Food Processors: Infectious, Toxigenic, Toxico-Infectious, Selected Emerging Pathogenic Bacteria

    NASA Astrophysics Data System (ADS)

    Behling, Robert G.; Eifert, Joseph; Erickson, Marilyn C.; Gurtler, Joshua B.; Kornacki, Jeffrey L.; Line, Erick; Radcliff, Roy; Ryser, Elliot T.; Stawick, Bradley; Yan, Zhinong

    This chapter, written by several contributing authors, is devoted to discussing selected microbes of contemporary importance. Microbes from three categories are described by the following: (1) infectious invasive agents like Salmonella, Listeria monocytogenes, and Campylobacter; (2) toxigenic pathogens such as Staphylococcus aureus, Bacillus cereus, and Clostridium botulinum; and (3) toxico-infectious agents like enterohemorrhagic Escherichia coli and Clostridium perfringens. In addition, emerging pathogens, like Cronobacter (Enterobacter) sakazakii, Arcobacter spp., and Mycobacterium avium subspecies paratuberculosis are also described.

  15. Oligo-DNA Custom Macroarray for Monitoring Major Pathogenic and Non-Pathogenic Fungi and Bacteria in the Phyllosphere of Apple Trees

    PubMed Central

    He, Ying-Hong; Isono, Sayaka; Shibuya, Makoto; Tsuji, Masaharu; Adkar Purushothama, Charith-Raj; Tanaka, Kazuaki; Sano, Teruo

    2012-01-01

    Background To monitor the richness in microbial inhabitants in the phyllosphere of apple trees cultivated under various cultural and environmental conditions, we developed an oligo-DNA macroarray for major pathogenic and non-pathogenic fungi and bacteria inhabiting the phyllosphere of apple trees. Methods and Findings First, we isolated culturable fungi and bacteria from apple orchards by an agar-plate culture method, and detected 32 fungal and 34 bacterial species. Alternaria, Aureobasidium, Cladosporium, Rhodotorula, Cystofilobasidium, and Epicoccum genera were predominant among the fungi, and Bacillus, Pseudomonas, Sphingomonas, Methylobacterium, and Pantoea genera were predominant among the bacteria. Based on the data, we selected 29 major non-pathogenic and 12 phytopathogenic fungi and bacteria as the targets of macroarray. Forty-one species-specific 40-base pair long oligo-DNA sequences were selected from the nucleotide sequences of rDNA-internal transcribed spacer region for fungi and 16S rDNA for bacteria. The oligo-DNAs were fixed on nylon membrane and hybridized with digoxigenin-labeled cRNA probes prepared for each species. All arrays except those for Alternaria, Bacillus, and their related species, were specifically hybridized. The array was sensitive enough to detect 103 CFU for Aureobasidium pullulans and Bacillus cereus. Nucleotide sequencing of 100 each of independent fungal rDNA-ITS and bacterial 16S-rDNA sequences from apple tree was in agreement with the macroarray data obtained using the same sample. Finally, we analyzed the richness in the microbial inhabitants in the samples collected from apple trees in four orchards. Major apple pathogens that cause scab, Alternaria blotch, and Marssonina blotch were detected along with several non-phytopathogenic fungal and bacterial inhabitants. Conclusions The macroarray technique presented here is a strong tool to monitor the major microbial species and the community structures in the phyllosphere of

  16. [The significance of glucose positive coliform bacteria and potentially pathogenic bacteria as an indicator of epidemiological safety of tap water].

    PubMed

    Zhuravlev, P V; Aleshnya, V V; Panasovets, O P; Morozova, A A; Artemova, T Z; Talaeva, Yu G; Zagaynova, A V

    2013-01-01

    Due to intensive anthropogenic pollution of water environment generally accepted indicators of epidemic security of water bodies--common bacteria (CB) and thermotolerant coliform bacteria (TCB) do not always permit to obtain an objective characterization of bacterial contamination of tap water. From the point of view of authors the integral index--glucose positive coliform bacteria most adequately reflect the sanitary-hygienic and epidemiological situation of water bodies. In monitoring for bacterial quality of tap water it is advisable to determine glucose positive coliform bacteria, that will provide the relevance of estimation of the epidemiological safety of water use. According to the method developed by the authors the calculation of the index of population risk of acute intestinal infections (AHI) occurrence in dependence on the quality of tap water in Azov and Tsimlyansk towns.

  17. Soil bacteria as sources of virulence signal providers promoting plant infection by Phytophthora pathogens.

    PubMed

    Kong, Ping; Hong, Chuanxue

    2016-01-01

    Phytophthora species are known as "plant destroyers" capable of initiating single zoospore infection in the presence of a quorum of chemical signals from the same or closely related species of oomycetes. Since the natural oomycete population is too low to reach a quorum necessary to initiate a disease epidemic, creation of the quorum is reliant on alternate sources. Here, we show that a soil bacterial isolate, Bacillus megaterium Sb5, promotes plant infection by Phytophthora species. In the presence of Sb5 exudates, colonization of rhododendron leaf discs by 12 Phytophthora species/isolates was significantly enhanced, single zoospores of P. nicotianae infected annual vinca and P. sojae race 25 successfully attacked a non-host plant, Nicotiana benthamiana as well as resistant soybean cultivars with RPS1a or RPS3a. Sb5 exudates, most notably the fractions larger than 3 kDa, promoted plant infection by improving zoospore swimming, germination and plant attachment. Sb5 exudates also stimulated infection hypha growth and upregulated effector gene expression. These results suggest that environmental bacteria are important sources of virulence signal providers that promote plant infection by Phytophthora species, advancing our understanding of biotic factors in the environmental component of the Phytophthora disease triangle and of communal infection of plant pathogens. PMID:27616267

  18. Microalgae mediated synthesis of silver nanoparticles and their antibacterial activity against pathogenic bacteria.

    PubMed

    Sudha, S S; Rajamanickam, Karthic; Rengaramanujam, J

    2013-05-01

    Silver nanoparticles is known to have antimicrobial affects. Cyanobacteria isolates from muthupet mangrove includes Aphanothece sp, Oscillatoria sp, Microcoleus sp, Aphanocapsa sp, Phormidium sp, Lyngbya sp, Gleocapsa sp, Synechococcus sp, Spirulina sp with were set in compliance with their cellular mechanism of nano silver creation, and were investigated by UV-VIS spectrophotometer, Energy-dispersive X-ray (EDX) and scanning electron microscopy (SEM). Silver nanoparticles were spherical shaped well distributed without aggregation in solution with an average size of about 40- 80 nm. Synthesised nano silver had antibacterial production on various organisms that provoked various diseases in humans. The cellular metabolites of Microcoleus sp. only created nano silver and it enhanced the antibacterial activity against test pathogenic bacteria from MTCC (Proteus vulgaris, Salmonella typhi, Vibrio cholera, Streptococcus sp., Bacillus subtilis, Staphylococcus aureus, Escherichia coli.) The antimicrobial assay was performed using 0.001 M concentration of nano silver in well diffusion method with positive control of appropriate standard antibiotic discs Cephotaxime, Ampicillin, Tetracyclin, Cephalexin etc. Synthesised silver nanoparticles acted as an effective antimicrobial agent and proved as an alternative for the development of new antimicrobial agents to combat the problem of resistance. PMID:23821828

  19. Marine Antimicrobial Peptides: Nature Provides Templates for the Design of Novel Compounds against Pathogenic Bacteria.

    PubMed

    Falanga, Annarita; Lombardi, Lucia; Franci, Gianluigi; Vitiello, Mariateresa; Iovene, Maria Rosaria; Morelli, Giancarlo; Galdiero, Massimiliano; Galdiero, Stefania

    2016-01-01

    The discovery of antibiotics for the treatment of bacterial infections brought the idea that bacteria would no longer endanger human health. However, bacterial diseases still represent a worldwide treat. The ability of microorganisms to develop resistance, together with the indiscriminate use of antibiotics, is mainly responsible for this situation; thus, resistance has compelled the scientific community to search for novel therapeutics. In this scenario, antimicrobial peptides (AMPs) provide a promising strategy against a wide array of pathogenic microorganisms, being able to act directly as antimicrobial agents but also being important regulators of the innate immune system. This review is an attempt to explore marine AMPs as a rich source of molecules with antimicrobial activity. In fact, the sea is poorly explored in terms of AMPs, but it represents a resource with plentiful antibacterial agents performing their role in a harsh environment. For the application of AMPs in the medical field limitations correlated to their peptide nature, their inactivation by environmental pH, presence of salts, proteases, or other components have to be solved. Thus, these peptides may act as templates for the design of more potent and less toxic compounds. PMID:27213366

  20. Perforin-2 is essential for intracellular defense of parenchymal cells and phagocytes against pathogenic bacteria.

    PubMed

    McCormack, Ryan M; de Armas, Lesley R; Shiratsuchi, Motoaki; Fiorentino, Desiree G; Olsson, Melissa L; Lichtenheld, Mathias G; Morales, Alejo; Lyapichev, Kirill; Gonzalez, Louis E; Strbo, Natasa; Sukumar, Neelima; Stojadinovic, Olivera; Plano, Gregory V; Munson, George P; Tomic-Canic, Marjana; Kirsner, Robert S; Russell, David G; Podack, Eckhard R

    2015-01-01

    Perforin-2 (MPEG1) is a pore-forming, antibacterial protein with broad-spectrum activity. Perforin-2 is expressed constitutively in phagocytes and inducibly in parenchymal, tissue-forming cells. In vitro, Perforin-2 prevents the intracellular replication and proliferation of bacterial pathogens in these cells. Perforin-2 knockout mice are unable to control the systemic dissemination of methicillin-resistant Staphylococcus aureus (MRSA) or Salmonella typhimurium and perish shortly after epicutaneous or orogastric infection respectively. In contrast, Perforin-2-sufficient littermates clear the infection. Perforin-2 is a transmembrane protein of cytosolic vesicles -derived from multiple organelles- that translocate to and fuse with bacterium containing vesicles. Subsequently, Perforin-2 polymerizes and forms large clusters of 100 Å pores in the bacterial surface with Perforin-2 cleavage products present in bacteria. Perforin-2 is also required for the bactericidal activity of reactive oxygen and nitrogen species and hydrolytic enzymes. Perforin-2 constitutes a novel and apparently essential bactericidal effector molecule of the innate immune system. PMID:26402460

  1. Perforin-2 is essential for intracellular defense of parenchymal cells and phagocytes against pathogenic bacteria.

    PubMed

    McCormack, Ryan M; de Armas, Lesley R; Shiratsuchi, Motoaki; Fiorentino, Desiree G; Olsson, Melissa L; Lichtenheld, Mathias G; Morales, Alejo; Lyapichev, Kirill; Gonzalez, Louis E; Strbo, Natasa; Sukumar, Neelima; Stojadinovic, Olivera; Plano, Gregory V; Munson, George P; Tomic-Canic, Marjana; Kirsner, Robert S; Russell, David G; Podack, Eckhard R

    2015-09-24

    Perforin-2 (MPEG1) is a pore-forming, antibacterial protein with broad-spectrum activity. Perforin-2 is expressed constitutively in phagocytes and inducibly in parenchymal, tissue-forming cells. In vitro, Perforin-2 prevents the intracellular replication and proliferation of bacterial pathogens in these cells. Perforin-2 knockout mice are unable to control the systemic dissemination of methicillin-resistant Staphylococcus aureus (MRSA) or Salmonella typhimurium and perish shortly after epicutaneous or orogastric infection respectively. In contrast, Perforin-2-sufficient littermates clear the infection. Perforin-2 is a transmembrane protein of cytosolic vesicles -derived from multiple organelles- that translocate to and fuse with bacterium containing vesicles. Subsequently, Perforin-2 polymerizes and forms large clusters of 100 Å pores in the bacterial surface with Perforin-2 cleavage products present in bacteria. Perforin-2 is also required for the bactericidal activity of reactive oxygen and nitrogen species and hydrolytic enzymes. Perforin-2 constitutes a novel and apparently essential bactericidal effector molecule of the innate immune system.

  2. Prevalence and significance of plasmid maintenance functions in the virulence plasmids of pathogenic bacteria.

    PubMed

    Sengupta, Manjistha; Austin, Stuart

    2011-07-01

    Virulence functions of pathogenic bacteria are often encoded on large extrachromosomal plasmids. These plasmids are maintained at low copy number to reduce the metabolic burden on their host. Low-copy-number plasmids risk loss during cell division. This is countered by plasmid-encoded systems that ensure that each cell receives at least one plasmid copy. Plasmid replication and recombination can produce plasmid multimers that hinder plasmid segregation. These are removed by multimer resolution systems. Equitable distribution of the resulting monomers to daughter cells is ensured by plasmid partition systems that actively segregate plasmid copies to daughter cells in a process akin to mitosis in higher organisms. Any plasmid-free cells that still arise due to occasional failures of replication, multimer resolution, or partition are eliminated by plasmid-encoded postsegregational killing systems. Here we argue that all of these three systems are essential for the stable maintenance of large low-copy-number plasmids. Thus, they should be found on all large virulence plasmids. Where available, well-annotated sequences of virulence plasmids confirm this. Indeed, virulence plasmids often appear to contain more than one example conforming to each of the three system classes. Since these systems are essential for virulence, they can be regarded as ubiquitous virulence factors. As such, they should be informative in the search for new antibacterial agents and drug targets.

  3. Perforin-2 is essential for intracellular defense of parenchymal cells and phagocytes against pathogenic bacteria

    PubMed Central

    McCormack, Ryan M; de Armas, Lesley R; Shiratsuchi, Motoaki; Fiorentino, Desiree G; Olsson, Melissa L; Lichtenheld, Mathias G; Morales, Alejo; Lyapichev, Kirill; Gonzalez, Louis E; Strbo, Natasa; Sukumar, Neelima; Stojadinovic, Olivera; Plano, Gregory V; Munson, George P; Tomic-Canic, Marjana; Kirsner, Robert S; Russell, David G; Podack, Eckhard R

    2015-01-01

    Perforin-2 (MPEG1) is a pore-forming, antibacterial protein with broad-spectrum activity. Perforin-2 is expressed constitutively in phagocytes and inducibly in parenchymal, tissue-forming cells. In vitro, Perforin-2 prevents the intracellular replication and proliferation of bacterial pathogens in these cells. Perforin-2 knockout mice are unable to control the systemic dissemination of methicillin-resistant Staphylococcus aureus (MRSA) or Salmonella typhimurium and perish shortly after epicutaneous or orogastric infection respectively. In contrast, Perforin-2-sufficient littermates clear the infection. Perforin-2 is a transmembrane protein of cytosolic vesicles -derived from multiple organelles- that translocate to and fuse with bacterium containing vesicles. Subsequently, Perforin-2 polymerizes and forms large clusters of 100 Å pores in the bacterial surface with Perforin-2 cleavage products present in bacteria. Perforin-2 is also required for the bactericidal activity of reactive oxygen and nitrogen species and hydrolytic enzymes. Perforin-2 constitutes a novel and apparently essential bactericidal effector molecule of the innate immune system. DOI: http://dx.doi.org/10.7554/eLife.06508.001 PMID:26402460

  4. Soil bacteria as sources of virulence signal providers promoting plant infection by Phytophthora pathogens

    PubMed Central

    Kong, Ping; Hong, Chuanxue

    2016-01-01

    Phytophthora species are known as “plant destroyers” capable of initiating single zoospore infection in the presence of a quorum of chemical signals from the same or closely related species of oomycetes. Since the natural oomycete population is too low to reach a quorum necessary to initiate a disease epidemic, creation of the quorum is reliant on alternate sources. Here, we show that a soil bacterial isolate, Bacillus megaterium Sb5, promotes plant infection by Phytophthora species. In the presence of Sb5 exudates, colonization of rhododendron leaf discs by 12 Phytophthora species/isolates was significantly enhanced, single zoospores of P. nicotianae infected annual vinca and P. sojae race 25 successfully attacked a non-host plant, Nicotiana benthamiana as well as resistant soybean cultivars with RPS1a or RPS3a. Sb5 exudates, most notably the fractions larger than 3 kDa, promoted plant infection by improving zoospore swimming, germination and plant attachment. Sb5 exudates also stimulated infection hypha growth and upregulated effector gene expression. These results suggest that environmental bacteria are important sources of virulence signal providers that promote plant infection by Phytophthora species, advancing our understanding of biotic factors in the environmental component of the Phytophthora disease triangle and of communal infection of plant pathogens. PMID:27616267

  5. Marine Antimicrobial Peptides: Nature Provides Templates for the Design of Novel Compounds against Pathogenic Bacteria

    PubMed Central

    Falanga, Annarita; Lombardi, Lucia; Franci, Gianluigi; Vitiello, Mariateresa; Iovene, Maria Rosaria; Morelli, Giancarlo; Galdiero, Massimiliano; Galdiero, Stefania

    2016-01-01

    The discovery of antibiotics for the treatment of bacterial infections brought the idea that bacteria would no longer endanger human health. However, bacterial diseases still represent a worldwide treat. The ability of microorganisms to develop resistance, together with the indiscriminate use of antibiotics, is mainly responsible for this situation; thus, resistance has compelled the scientific community to search for novel therapeutics. In this scenario, antimicrobial peptides (AMPs) provide a promising strategy against a wide array of pathogenic microorganisms, being able to act directly as antimicrobial agents but also being important regulators of the innate immune system. This review is an attempt to explore marine AMPs as a rich source of molecules with antimicrobial activity. In fact, the sea is poorly explored in terms of AMPs, but it represents a resource with plentiful antibacterial agents performing their role in a harsh environment. For the application of AMPs in the medical field limitations correlated to their peptide nature, their inactivation by environmental pH, presence of salts, proteases, or other components have to be solved. Thus, these peptides may act as templates for the design of more potent and less toxic compounds. PMID:27213366

  6. Novel impedimetric immunosensor for detection of pathogenic bacteria Streptococcus pyogenes in human saliva.

    PubMed

    Ahmed, Asif; Rushworth, Jo V; Wright, John D; Millner, Paul A

    2013-12-17

    Streptococcus pyogenes , also known as group A streptococcus (GAS), is a Gram positive human pathogen responsible for invasive and noninvasive human infections with a high incidence rate. Traditional detection methods involve cell culture and PCR, which are limited by long processing times or the need for high cost equipment. Impedance-based electrochemical immunosensors provide an alternative by which precise and rapid quantitative detection of the organism can help with rapid clinical decisions. To bring a biosensor for point-of-care applications to market, strict optimization of each level of construction and operation is required. In this paper, commercial screen-printed gold electrodes have been used to construct polytyramine (Ptyr)-based immunosensors. Biotin tagged whole antibodies against S. pyogenes were conjugated to Ptyr amine group via biotin-NeutrAvidin coupling. Sensors were optimized at each level of construction, particularly for Ptyr electrodeposition and antibody concentration, to optimize signal and specificity. Scanning electron microscopy, fluorescence microscopy, and on-sensor analysis (HRP conjugated enhanced chemiluminescence-based semiquantitative method) to detect Ptyr surface amine and bound antibody were performed as supporting techniques. Cumulative and single shot incubations had shown detection range of 100 to 10(5) cells per 10 μL and 100 to 10(4) cells per 10 μL of bacteria in PBS, respectively. Sensors were also able to specifically detect S. pyogenes in 50% (v/v) human saliva, with good selectivity and low cross-reactivity.

  7. High-throughput real-time electrochemical monitoring of LAMP for pathogenic bacteria detection.

    PubMed

    Safavieh, Mohammadali; Ahmed, Minhaz Uddin; Ng, Andy; Zourob, Mohammed

    2014-08-15

    One of the significant challenges in healthcare is the development of point-of-care (POC) diagnostics. POC diagnostics require low-cost devices that offer portability, simplicity in operation and the ability for high-throughput and quantitative analysis. Here, we present a novel roll-to-roll ribbon fluid-handling device for electrochemical real-time monitoring of nucleic acid (NA) amplification and bacteria detection. The device rendered loop-mediated isothermal amplification (LAMP) and real-time electrochemical detection based on the interaction between LAMP amplicon and the redox-reactive osmium complex. We have shown the detection of 30CFU/ml of Escherichia coli (in the range between 30 and 3×10(7)CFU/ml) and 200CFU/ml of Staphylococcus aureus (in the range of 200-2×10(5)CFU/ml) cultured samples in both real-time and end point detection. This device can be used for the detection of various Gram-negative and a number of Gram-positive bacterial pathogens with high sensitivity and specificity in a high-throughput format. Using a roll-to-roll cassette approach, we could detect 12 samples in one assay. Since the LAMP and electrochemical analysis are implemented within sealed flexible biochips, time-consuming processing steps are not required and the risk of contamination is significantly reduced.

  8. Comparative Study of Eis-like Enzymes from Pathogenic and Nonpathogenic Bacteria.

    PubMed

    Green, Keith D; Pricer, Rachel E; Stewart, Megan N; Garneau-Tsodikova, Sylvie

    2015-06-12

    Antibiotic resistance is a growing problem worldwide. Of particular importance is the resistance of Mycobacterium tuberculosis (Mtb) to currently available antibiotics used in the treatment of infected patients. Up-regulation of an aminoglycoside (AG) acetyltransferase, the enhanced intracellular survival (Eis) protein of Mtb (Eis_Mtb), is responsible for resistance to the second-line injectable drug kanamycin A in a number of Mtb clinical isolates. This acetyltransferase is known to modify AGs, not at a single position, as usual for this type of enzyme, but at multiple amine sites. We identified, using in silico techniques, 22 homologues from a wide variety of bacteria, that we then cloned, purified, and biochemically studied. From the selected Eis homologues, 7 showed the ability to modify AGs to various degrees and displayed both similarities and differences when compared to Eis_Mtb. In addition, an inhibitor proved to be active against all homologues tested. Our findings show that this family of acetyltransferase enzymes exists in both mycobacteria and non-mycobacteria and in both pathogenic and nonpathogenic species. The bacterial strains described herein should be monitored for rising resistance rates to AGs. PMID:27622743

  9. Rapid Detection of Pathogenic Bacteria from Fresh Produce by Filtration and Surface-Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wu, Xiaomeng; Han, Caiqin; Chen, Jing; Huang, Yao-Wen; Zhao, Yiping

    2016-04-01

    The detection of Salmonella Poona from cantaloupe cubes and E. coli O157:H7 from lettuce has been explored by using a filtration method and surface-enhanced Raman spectroscopy (SERS) based on vancomycin-functionalized silver nanorod array substrates. It is found that with a two-step filtration process, the limit of detection (LOD) of Salmonella Poona from cantaloupe cubes can be as low as 100 CFU/mL in less than 4 h, whereas the chlorophyll in the lettuce causes severe SERS spectral interference. To improve the LOD of lettuce, a three-step filtration method with a hydrophobic filter is proposed. The hydrophobic filter can effectively eliminate the interferences from chlorophyll and achieve a LOD of 1000 CFU/mL detection of E. coli O157:H7 from lettuce samples within 5 h. With the low LODs and rapid detection time, the SERS biosensing platform has demonstrated its potential as a rapid, simple, and inexpensive means for pathogenic bacteria detection from fresh produce.

  10. Factors Affecting Microbial Load and Profile of Potential Pathogens and Food Spoilage Bacteria from Household Kitchen Tables

    PubMed Central

    Latouche, Melissa Cathleen

    2016-01-01

    The aim was to study the bacterial load and isolate potential pathogens and food spoilage bacteria from kitchen tables, including preparation tables and dining tables. Methods. A total of 53 households gave their consent for participation. The samples were collected by swabbing over an area of 5 cm by 5 cm of the tables and processed for bacterial count which was read as colony forming units (CFU), followed by isolation and identification of potential pathogens and food spoilage bacteria. Result. Knowledge about hygiene was not always put into practice. Coliforms, Enterococcus spp., Pseudomonas spp., Proteus spp., and S. aureus were detected from both dining and preparation tables. The mean CFU and presence of potential pathogens were significantly affected by the hygienic practices of the main food handler of the house, materials of kitchen tables, use of plastic covers, time of sample collection, use of multipurpose sponges/towels for cleaning, and the use of preparation tables as chopping boards (p < 0.05). Conclusion. Kitchen tables could be very important source of potential pathogens and food spoilage bacteria causing foodborne diseases. Lack of hygiene was confirmed by presence of coliforms, S. aureus, and Enterococcus spp. The use of plastic covers, multipurpose sponges, and towels should be discouraged. PMID:27446220

  11. Factors Affecting Microbial Load and Profile of Potential Pathogens and Food Spoilage Bacteria from Household Kitchen Tables.

    PubMed

    Biranjia-Hurdoyal, Susheela; Latouche, Melissa Cathleen

    2016-01-01

    The aim was to study the bacterial load and isolate potential pathogens and food spoilage bacteria from kitchen tables, including preparation tables and dining tables. Methods. A total of 53 households gave their consent for participation. The samples were collected by swabbing over an area of 5 cm by 5 cm of the tables and processed for bacterial count which was read as colony forming units (CFU), followed by isolation and identification of potential pathogens and food spoilage bacteria. Result. Knowledge about hygiene was not always put into practice. Coliforms, Enterococcus spp., Pseudomonas spp., Proteus spp., and S. aureus were detected from both dining and preparation tables. The mean CFU and presence of potential pathogens were significantly affected by the hygienic practices of the main food handler of the house, materials of kitchen tables, use of plastic covers, time of sample collection, use of multipurpose sponges/towels for cleaning, and the use of preparation tables as chopping boards (p < 0.05). Conclusion. Kitchen tables could be very important source of potential pathogens and food spoilage bacteria causing foodborne diseases. Lack of hygiene was confirmed by presence of coliforms, S. aureus, and Enterococcus spp. The use of plastic covers, multipurpose sponges, and towels should be discouraged.

  12. Factors Affecting Microbial Load and Profile of Potential Pathogens and Food Spoilage Bacteria from Household Kitchen Tables.

    PubMed

    Biranjia-Hurdoyal, Susheela; Latouche, Melissa Cathleen

    2016-01-01

    The aim was to study the bacterial load and isolate potential pathogens and food spoilage bacteria from kitchen tables, including preparation tables and dining tables. Methods. A total of 53 households gave their consent for participation. The samples were collected by swabbing over an area of 5 cm by 5 cm of the tables and processed for bacterial count which was read as colony forming units (CFU), followed by isolation and identification of potential pathogens and food spoilage bacteria. Result. Knowledge about hygiene was not always put into practice. Coliforms, Enterococcus spp., Pseudomonas spp., Proteus spp., and S. aureus were detected from both dining and preparation tables. The mean CFU and presence of potential pathogens were significantly affected by the hygienic practices of the main food handler of the house, materials of kitchen tables, use of plastic covers, time of sample collection, use of multipurpose sponges/towels for cleaning, and the use of preparation tables as chopping boards (p < 0.05). Conclusion. Kitchen tables could be very important source of potential pathogens and food spoilage bacteria causing foodborne diseases. Lack of hygiene was confirmed by presence of coliforms, S. aureus, and Enterococcus spp. The use of plastic covers, multipurpose sponges, and towels should be discouraged. PMID:27446220

  13. Bifidobacterium longum-fermented broccoli supernatant inhibited the growth of Candida albicans and some pathogenic bacteria in vitro.

    PubMed

    Suido, Hirohisa; Miyao, Manabu

    2008-06-01

    The aim of this study is to develop a growth inhibitory material against some pathogenic microorganisms, using beneficial bacteria such as Bifidobacterium species and certain types of vegetables which can be good substrates for the growth of the beneficial bacteria. At first, various vegetable juices were screened for the growth promotion of Bifidobacterium longum etc. Among the vegetables tested, broccoli (Brassica oleracea L. var. botrytis L.) and cabbage (Brassica oleracea L. var. capitata L.) showed excellent growth promoting activities for B. longum. Secondly, the B. longum-fermented broccoli (BFB) and Lactobacillus pentosus-fermented broccoli (LFB) supernatants were prepared and the growth inhibitory activities against Candida albicans were determined. Both of them showed dose-dependent, growth inhibitory effects, and the effect of BFB was superior to LFB. It was thought that the superior effect of BFB could be mainly attributed to the acids, especially acetic acid, produced by B. longum. BFB also inhibited some pathogenic bacteria such as Streptococcus mutans and Porphylomonas gingivalis. In conclusion, broccoli was found to be a good growth-promoting substance for B. longum. The fermented product, BFB, appears to be a usable material that inhibits the growth of C. albicans and some pathogenic bacteria. PMID:18661679

  14. Cultured enterocytes internalise bacteria across their basolateral surface for, pathogen-inhibitable, trafficking to the apical compartment

    PubMed Central

    Dean, Paul; Quitard, Sabine; Bulmer, David M.; Roe, Andrew J.; Kenny, Brendan

    2015-01-01

    In vitro- and in vivo-polarised absorptive epithelia (enterocytes) are considered to be non-phagocytic towards bacteria with invasive pathogenic strains relying on virulence factors to ‘force’ entry. Here, we report a serendipitous discovery that questions these beliefs. Thus, we uncover in well-established models of human small (Caco-2; TC-7) and large (T84) intestinal enterocytes a polarization-dependent mechanism that can transfer millions of bacteria from the basal to apical compartment. Antibiotic-protection assays, confocal imaging and drug inhibitor data are consistent with a transcellular route in which internalized, basolateral-membrane enclosed bacteria are trafficked to and across the apical surface. Basal-to-apical transport of non-pathogenic bacteria (and inert beads) challenged the idea of pathogens relying on virulence factors to force entry. Indeed, studies with Salmonella demonstrated that it’s entry-forcing virulence factor (SPI-I) was not required to enter via the basolateral surface but to promote another virulence-associated event (intra-enterocyte accumulation). PMID:26612456

  15. The influence of predation and competition on the survival of commensal and pathogenic fecal bacteria in aquatic habitats.

    PubMed

    Wanjugi, Pauline; Harwood, Valerie J

    2013-02-01

    The role of fecal indicator bacteria (FIB) in water quality assessment is to provide a warning of the increased risk of pathogen presence. An effective surrogate for waterborne pathogens would have similar survival characteristics in aquatic environments. Although the effect of abiotic factors such as sunlight and salinity on the survival of FIB and pathogens are becoming better understood, the effect of the indigenous microbiota is not well characterized. The influence of biotic factors on the survival of non-pathogenic Escherichia coli, Enterococcus faecalis, and E. coli O157:H7 were compared in fresh (river) water and sediments over 5 days. Treatments were (i) disinfection (filtration of water and baking of sediments) to remove indigenous protozoa (predators) and bacteria (competitors), and (ii) kanamycin treatment to reduce competition from indigenous bacteria. The disinfection treatment significantly increased survival of E. coli, E. coli O157:H7 and Ent. faecalis in the water column. In sediments, survival of FIB but not that of E. coli O157:H7 increased in disinfected treatments, indicating that the pathogen's survival was unaffected by the natural microbiota. Location (water or sediment) influenced bacterial survival more than species/type in the disinfection experiment. In the competition experiments where only the natural bacterial flora was manipulated, the addition of kanamycin did not affect the survival of Ent. faecalis, but resulted in greater survival of E. coli in water and sediment. Species/type influenced survival more than the level of competition in this experiment. This study demonstrates the complexity of interactions of FIB and pathogens with indigenous microbiota and location in aquatic habitats, and argues against over-generalizing conclusions derived from experiments restricted to a particular organism or habitat.

  16. Biosensors based on modularly designed synthetic peptides for recognition, detection and live/dead differentiation of pathogenic bacteria.

    PubMed

    Liu, Xiaobo; Marrakchi, Mouna; Xu, Dawei; Dong, He; Andreescu, Silvana

    2016-06-15

    Rapid and sensitive detection of bacterial pathogens is critical for assessing public health, food and environmental safety. We report the use of modularly designed and site-specifically oriented synthetic antimicrobial peptides (sAMPs) as novel recognition agents enabling detection and quantification of bacterial pathogens. The oriented assembly of the synthetic peptides on electrode surfaces through an engineered cysteine residue coupled with impedimetric detection facilitated rapid and sensitive detection of bacterial pathogens with a detection limit of 10(2)CFU/mL for four bacterial strains including Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). The approach enabled differentiation between live and dead bacteria. The fabrication of the sAMPs functionalized surface and the importance of the sAMPs orientation for providing optimum recognition and detection ability against pathogens are discussed. The proposed methodology provides a universal platform for the detection of bacterial pathogens based on engineered peptides, as alternative to the most commonly used immunological and gene based assays. The method can also be used to fabricate antimicrobial coatings and surfaces for inactivation and screening of viable bacteria. PMID:26802747

  17. Biosensors based on modularly designed synthetic peptides for recognition, detection and live/dead differentiation of pathogenic bacteria.

    PubMed

    Liu, Xiaobo; Marrakchi, Mouna; Xu, Dawei; Dong, He; Andreescu, Silvana

    2016-06-15

    Rapid and sensitive detection of bacterial pathogens is critical for assessing public health, food and environmental safety. We report the use of modularly designed and site-specifically oriented synthetic antimicrobial peptides (sAMPs) as novel recognition agents enabling detection and quantification of bacterial pathogens. The oriented assembly of the synthetic peptides on electrode surfaces through an engineered cysteine residue coupled with impedimetric detection facilitated rapid and sensitive detection of bacterial pathogens with a detection limit of 10(2)CFU/mL for four bacterial strains including Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). The approach enabled differentiation between live and dead bacteria. The fabrication of the sAMPs functionalized surface and the importance of the sAMPs orientation for providing optimum recognition and detection ability against pathogens are discussed. The proposed methodology provides a universal platform for the detection of bacterial pathogens based on engineered peptides, as alternative to the most commonly used immunological and gene based assays. The method can also be used to fabricate antimicrobial coatings and surfaces for inactivation and screening of viable bacteria.

  18. The inhibitory effect of Thymus vulgaris extracts on the planktonic form and biofilm structures of six human pathogenic bacteria

    PubMed Central

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2015-01-01

    Objective: Microorganisms are responsible for many problems in industry and medicine because of biofilm formation. Therefore, this study was aimed to examine the effect of Thymus vulgaris (T. vulgaris) extracts on the planktonic form and biofilm structures of six pathogenic bacteria. Materials and methods: Antimicrobial activities of the plant extracts against the planktonic form of the bacteria were determined using the disc diffusion method. MIC and MBC values were evaluated using macrobroth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. Results: According to disc diffusion test (MIC and MBC), the ability of Thymus vulgaris (T. vulgaris ) extracts for inhibition of bacteria in planktonic form was confirmed. In dealing with biofilm structures, the inhibitory effect of the extracts was directly correlated to their concentration. Except for the inhibition of biofilm formation, efficacy of each extract was independent from type of solvent. Conclusion: According to the potential of Thymus vulgaris (T. vulgaris) extracts to inhibit the test bacteria in planktonic and biofilm form, it can be suggested that Thymus vulgaris (T. vulgaris) extracts can be applied as antimicrobial agents against the pathogenic bacteria particularly in biofilm forms. PMID:26442753

  19. Emerging role of bacteria in oral carcinogenesis: a review with special reference to perio-pathogenic bacteria.

    PubMed

    Perera, Manosha; Al-Hebshi, Nezar Noor; Speicher, David J; Perera, Irosha; Johnson, Newell W

    2016-01-01

    Oral cancer, primarily oral squamous cell carcinoma (OSCC), continues to be a major global health problem with high incidence and low survival rates. While the major risk factors for this malignancy, mostly lifestyle related, have been identified, around 15% of oral cancer cases remain unexplained. In light of evidence implicating bacteria in the aetiology of some cancer types, several epidemiological studies have been conducted in the last decade, employing methodologies ranging from traditional culture techniques to 16S rRNA metagenomics, to assess the possible role of bacteria in OSCC. While these studies have demonstrated differences in microbial composition between cancerous and healthy tissues, they have failed to agree on specific bacteria or patterns of oral microbial dysbiosis to implicate in OSCC. On the contrary, some oral taxa, particularly Porphyromonas gingivalis and Fusobacterium nucleatum, show strong oral carcinogenic potential in vitro and in animal studies. Bacteria are thought to contribute to oral carcinogenesis via inhibition of apoptosis, activation of cell proliferation, promotion of cellular invasion, induction of chronic inflammation, and production of carcinogens. This narrative review provides a critical analysis of and an update on the association between bacteria and oral carcinogenesis and the possible mechanisms underlying it. PMID:27677454

  20. OEM--a new medium for rapid isolation of onion-pathogenic and onion-associated bacteria.

    PubMed

    Zaid, Ali M; Bonasera, Jean M; Beer, Steven V

    2012-12-01

    Onions (Allium cepa L.) are plagued by a number of bacterial pathogens including Pantoea ananatis, P. agglomerans, Burkholderia cepacia, Enterobacter cloacae, Pectobacterium carotovorum subsp. carotovorum, Xanthomonas axonopodis pv. axonopodis and several Pseudomonas spp. We developed a semi-selective medium, termed onion extract medium (OEM), to selectively and rapidly isolate bacteria pathogenic to and associated with onions and onion-related samples including bulbs, seeds, sets, transplant seedlings, soil and water. Most strains of interest grow sufficiently on OEM in 24h at 28°C for tentative identification based on colony morphology, facilitating further characterization by microbiological and/or molecular means. PMID:23041494

  1. Molecular characterization by amplified ribosomal DNA restriction analysis and antimicrobial potential of endophytic fungi isolated from Luehea divaricata (Malvaceae) against plant pathogenic fungi and pathogenic bacteria.

    PubMed

    Bernardi-Wenzel, J; Garcia, A; Azevedo, J L; Pamphile, J A

    2013-01-01

    Luehea divaricata is an important plant in popular medicine; it is used for its depurative, anti-inflammatory, and other therapeutic activities. We evaluated the antimicrobial activity of endophytic fungi isolated from leaves of L. divaricata against phytopathogens and pathogenic bacteria, and characterized the isolates based on amplified ribosomal DNA restriction analysis (ARDRA). The in vitro antagonistic activity of these endophytes against the phytopathogen Alternaria alternata was assayed by dual culture technique. Based on this evaluation of antimicrobial activity, we extracted secondary metabolites from nine endophytic fungi by partitioning in ethyl acetate and methanol. These were tested against the phytopathogens A. alternata, Colletotrichum sp and Moniliophthora perniciosa, and against the human pathogenic bacteria Escherichia coli and Staphylococcus aureus. Molecular characterization by ARDRA technique was used for phylogenetic analysis, based on comparison with sequences in GenBank. The endophytes had varied effects on A. alternata. One isolate produced an inhibition halo against M. perniciosa and against E. coli. This antibiosis activity indicates a role in the protection of the plant against microbial pathogens in nature, with potential for pharmaceutical and agricultural applications. Based on ARDRA, the 13 isolates were grouped. We found three different haplotypes of Phomopsis sp, showing interspecific variability. It appears that examination of the microbial community associated with medicinal plants of tropical regions has potential as a useful strategy to look for species with biotechnological applications. PMID:24301768

  2. 1,3-Propanediol production by new recombinant Escherichia coli containing genes from pathogenic bacteria.

    PubMed

    Przystałowska, Hanna; Zeyland, Joanna; Szymanowska-Powałowska, Daria; Szalata, Marlena; Słomski, Ryszard; Lipiński, Daniel

    2015-02-01

    1,3-Propanediol (1,3-PDO) is an organic compound, which is a valuable intermediate product, widely used as a monomer for synthesizing biodegradable polymers, increasing their strength; as well as an ingredient of textile, cosmetic and medical products. 1,3-PDO is mostly synthesized chemically. Global companies have developed technologies for 1,3-PDO synthesis from petroleum products such as acrolein and ethylene oxide. A potentially viable alternative is offered by biotechnological processes using microorganisms capable of synthesizing 1,3-PDO from renewable substrates (waste glycerol, a by-product of biofuel production, or glucose). In the present study, genes from Citrobacter freundii and Klebsiella pneumoniae were introduced into Escherichia coli bacteria to enable the synthesis of 1,3-PDO from waste glycerol. These strains belong to the best 1,3-PDO producers, but they are pathogenic, which restricts their application in industrial processes. The present study involved the construction of two gene expression constructs, containing a total of six heterologous glycerol catabolism pathway genes from C. freundii ATCC 8090 and K. pneumoniae ATCC 700721. Heterologous genes encoding glycerol dehydratase (dhaBCE) and the glycerol dehydratase reactivation factor (dhaF, dhaG) from C. freundii and gene encoding 1,3-PDO oxidoreductase (dhaT) from K. pneumoniae were expressed in E. coli under the control of the T7lac promoter. An RT-PCR analysis and overexpression confirmed that 1,3-PDO synthesis pathway genes were expressed on the RNA and protein levels. In batch fermentation, recombinant E. coli bacteria used 32.6gl(-1) of glycerol to produce 10.6 gl(-1) of 1,3-PDO, attaining the efficiency of 0.4 (mol₁,₃-PDO molglycerol(-1)). The recombinant E. coli created is capable of metabolizing glycerol to produce 1,3-PDO, and the efficiency achieved provides a significant research potential of the bacterium. In the face of shortage of fossil fuel supplies and climate warming

  3. The Phytoplankton Nannochloropsis oculata Enhances the Ability of Roseobacter Clade Bacteria to Inhibit the Growth of Fish Pathogen Vibrio anguillarum

    PubMed Central

    Sharifah, Emilia Noor; Eguchi, Mitsuru

    2011-01-01

    Background Phytoplankton cultures are widely used in aquaculture for a variety of applications, especially as feed for fish larvae. Phytoplankton cultures are usually grown in outdoor tanks using natural seawater and contain probiotic or potentially pathogenic bacteria. Some Roseobacter clade isolates suppress growth of the fish pathogen Vibrio anguillarum. However, most published information concerns interactions between probiotic and pathogenic bacteria, and little information is available regarding the importance of phytoplankton in these interactions. The objectives of this study, therefore, were to identify probiotic Roseobacter clade members in phytoplankton cultures used for rearing fish larvae and to investigate their inhibitory activity towards bacterial fish pathogens in the presence of the phytoplankton Nannochloropsis oculata. Methodology/Principal Findings The fish pathogen V. anguillarum, was challenged with 6 Roseobacter clade isolates (Sulfitobacter sp. (2 strains), Thalassobius sp., Stappia sp., Rhodobacter sp., and Antarctobacter sp.) from phytoplankton cultures under 3 different nutritional conditions. In an organic nutrient-rich medium (VNSS), 6 Roseobacter clade isolates, as well as V. anguillarum, grew well (109 CFU/ml), even when cocultured. In contrast, in a phytoplankton culture medium (ESM) based on artificial seawater, coculture with the 6 isolates decreased the viability of V. anguillarum by approximately more than 10-fold. Excreted substances in media conditioned by growth of the phytoplankton N. oculata (NCF medium) resulted in the complete eradication of V. anguillarum when cocultured with the roseobacters. Autoclaved NCF had the same inhibitory effect. Furthermore, Sulfitobacter sp. much more efficiently incorporated 14C- photosynthetic metabolites (14C-EPM) excreted by N. oculata than did V. anguillarum. Conclusion/Significance Cocultures of a phytoplankton species and Roseobacter clade members exhibited a greater antibacterial

  4. Perception of pathogenic or beneficial bacteria and their evasion of host immunity: pattern recognition receptors in the frontline

    PubMed Central

    Trdá, Lucie; Boutrot, Freddy; Claverie, Justine; Brulé, Daphnée; Dorey, Stephan; Poinssot, Benoit

    2015-01-01

    Plants are continuously monitoring the presence of microorganisms to establish an adapted response. Plants commonly use pattern recognition receptors (PRRs) to perceive microbe- or pathogen-associated molecular patterns (MAMPs/PAMPs) which are microorganism molecular signatures. Located at the plant plasma membrane, the PRRs are generally receptor-like kinases (RLKs) or receptor-like proteins (RLPs). MAMP detection will lead to the establishment of a plant defense program called MAMP-triggered immunity (MTI). In this review, we overview the RLKs and RLPs that assure early recognition and control of pathogenic or beneficial bacteria. We also highlight the crucial function of PRRs during plant-microbe interactions, with a special emphasis on the receptors of the bacterial flagellin and peptidoglycan. In addition, we discuss the multiple strategies used by bacteria to evade PRR-mediated recognition. PMID:25904927

  5. Saccharomyces cerevisiae cells harboring the gene encoding sarcotoxin IA secrete a peptide that is toxic to plant pathogenic bacteria.

    PubMed

    Aly, R; Granot, D; Mahler-Slasky, Y; Halpern, N; Nir, D; Galun, E

    1999-06-01

    Sarcotoxin IA is a cecropin-type antibacterial protein produced by the flesh fly, Sarcophaga peregrina. Similar to other bactericidal small proteins produced by insects, sarcotoxin IA is released into the hemolymph of larvae and nymphs upon mechanical injury or bacterial infection. The gene (sarco) that encodes this toxin was introduced into Saccharomyces cerevisiae yeast cells and was expressed under a constitutive yeast promoter. The transformed yeast cells were grown in a liquid medium, and a peptide with a similar molecular size to that of the mature sarcotoxin IA was detected in the medium by Western blot analysis. The secreted sarcotoxin-like peptide (SLP) had a potent cytotoxic effect against several bacteria, including plant pathogenic bacteria, similar to the toxic effects of the authentic sarcotoxin IA. Erwinia carotovora was more susceptible to the toxic medium than Pseudomonas solanacearum and Pseudomonas syringae pv. lachrymans. Thus, yeast may be used in the production of such proteins for employment against various bacterial pathogens.

  6. Genomic fluidity and pathogenic bacteria: applications in diagnostics, epidemiology and intervention.

    PubMed

    Ahmed, Niyaz; Dobrindt, Ulrich; Hacker, Jörg; Hasnain, Seyed E

    2008-05-01

    The increasing availability of DNA-sequence information for multiple pathogenic and non-pathogenic variants of individual bacterial species has indicated that both DNA acquisition and genome reduction have important roles in genome evolution. Such genomic fluidity, which is found in human pathogens such as Escherichia coli, Helicobacter pylori and Mycobacterium tuberculosis, has important consequences for the clinical management of the diseases that are caused by these pathogens and for the development of diagnostics and new molecular epidemiological methods.

  7. Antimicrobial activities of chicken β-defensin (4 and 10) peptides against pathogenic bacteria and fungi

    PubMed Central

    Yacoub, Haitham A.; Elazzazy, Ahmed M.; Abuzinadah, Osama A. H.; Al-Hejin, Ahmed M.; Mahmoud, Maged M.; Harakeh, Steve M.

    2015-01-01

    Host Defense Peptides (HDPs) are small cationic peptides found in several organisms. They play a vital role in innate immunity response and immunomodulatory stimulation. This investigation was designed to study the antimicrobial activities of β-defensin peptide-4 (sAvBD-4) and 10 (sAvBD-4) derived from chickens against pathogenic organisms including bacteria and fungi. Ten bacterial strains and three fungal species were used in investigation. The results showed that the sAvBD-10 displayed a higher bactericidal potency against all the tested bacterial strains than that of sAvBD-4. The exhibited bactericidal activity was significant against almost the different bacterial strains at different peptide concentrations except for that of Pseudomonas aeruginosa (P. aeruginosa) and Streptococcus bovis (Str. bovis) strains where a moderate effect was noted. Both peptides were effective in the inactivation of fungal species tested yielding a killing rate of up to 95%. The results revealed that the synthetic peptides were resistant to salt at a concentration of 50 mM NaCl. However, they lost antimicrobial potency when applied in the presence of high salt concentrations. Based on blood hemolysis studies, a little hemolytic effect was showed in the case of both peptides even when applied at high concentrations. The data obtained from this study indicated that synthetic avian peptides exhibit strong antibacterial and antifungal activity. In conclusion, future work and research should be tailored to a better understanding of the mechanisms of action of those peptides and their potential use in the pharmaceutical industry to help reduce the incidence and impact of infectious agent and be marketed as a naturally occurring antibiotic. PMID:25941665

  8. Antimicrobial activities of chicken β-defensin (4 and 10) peptides against pathogenic bacteria and fungi.

    PubMed

    Yacoub, Haitham A; Elazzazy, Ahmed M; Abuzinadah, Osama A H; Al-Hejin, Ahmed M; Mahmoud, Maged M; Harakeh, Steve M

    2015-01-01

    Host Defense Peptides (HDPs) are small cationic peptides found in several organisms. They play a vital role in innate immunity response and immunomodulatory stimulation. This investigation was designed to study the antimicrobial activities of β-defensin peptide-4 (sAvBD-4) and 10 (sAvBD-4) derived from chickens against pathogenic organisms including bacteria and fungi. Ten bacterial strains and three fungal species were used in investigation. The results showed that the sAvBD-10 displayed a higher bactericidal potency against all the tested bacterial strains than that of sAvBD-4. The exhibited bactericidal activity was significant against almost the different bacterial strains at different peptide concentrations except for that of Pseudomonas aeruginosa (P. aeruginosa) and Streptococcus bovis (Str. bovis) strains where a moderate effect was noted. Both peptides were effective in the inactivation of fungal species tested yielding a killing rate of up to 95%. The results revealed that the synthetic peptides were resistant to salt at a concentration of 50 mM NaCl. However, they lost antimicrobial potency when applied in the presence of high salt concentrations. Based on blood hemolysis studies, a little hemolytic effect was showed in the case of both peptides even when applied at high concentrations. The data obtained from this study indicated that synthetic avian peptides exhibit strong antibacterial and antifungal activity. In conclusion, future work and research should be tailored to a better understanding of the mechanisms of action of those peptides and their potential use in the pharmaceutical industry to help reduce the incidence and impact of infectious agent and be marketed as a naturally occurring antibiotic.

  9. Suppression of Emergence of Resistance in Pathogenic Bacteria: Keeping Our Powder Dry, Part 2.

    PubMed

    Drusano, G L; Hope, William; MacGowan, Alasdair; Louie, Arnold

    2016-03-01

    We are in a crisis of bacterial resistance. For economic reasons, most pharmaceutical companies are abandoning antimicrobial discovery efforts, while, in health care itself, infection control and antibiotic stewardship programs have generally failed to prevent the spread of drug-resistant bacteria. At this point, what can be done? The first step has been taken. Governments and international bodies have declared there is a worldwide crisis in antibiotic drug resistance. As discovery efforts begin anew, what more can be done to protect newly developing agents and improve the use of new drugs to suppress resistance emergence? A neglected path has been the use of recent knowledge regarding antibiotic dosing as single agents and in combination to minimize resistance emergence, while also providing sufficient early bacterial kill. In this review, we look at the data for resistance suppression. Approaches include increasing the intensity of therapy to suppress resistant subpopulations; developing concepts of clinical breakpoints to include issues surrounding suppression of resistance; and paying attention to the duration of therapy, which is another important issue for resistance suppression. New understanding of optimizing combination therapy is of interest for difficult-to-treat pathogens like Pseudomonas aeruginosa, Acinetobacter spp., and multidrug-resistant (MDR) Enterobacteriaceae. These lessons need to be applied to our old drugs as well to preserve them and to be put into national and international antibiotic resistance strategies. As importantly, from a regulatory perspective, new chemical entities should have a resistance suppression plan at the time of regulatory review. In this way, we can make the best of our current situation and improve future prospects. PMID:26711766

  10. Suppression of Emergence of Resistance in Pathogenic Bacteria: Keeping Our Powder Dry, Part 1.

    PubMed

    Drusano, G L; Louie, Arnold; MacGowan, Alasdair; Hope, William

    2016-03-01

    We are in a crisis of bacterial resistance. For economic reasons, most pharmaceutical companies are abandoning antimicrobial discovery efforts, while, in health care itself, infection control and antibiotic stewardship programs have generally failed to prevent the spread of drug-resistant bacteria. At this point, what can be done? The first step has been taken. Governments and international bodies have declared there is a worldwide crisis in antibiotic drug resistance. As discovery efforts begin anew, what more can be done to protect newly developing agents and improve the use of new drugs to suppress resistance emergence? A neglected path has been the use of recent knowledge regarding antibiotic dosing as single agents and in combination to minimize resistance emergence, while also providing sufficient early bacterial kill. In this review, we look at the data for resistance suppression. Approaches include increasing the intensity of therapy to suppress resistant subpopulations; developing concepts of clinical breakpoints to include issues surrounding suppression of resistance; and paying attention to the duration of therapy, which is another important issue for resistance suppression. New understanding of optimizing combination therapy is of interest for difficult-to-treat pathogens like Pseudomonas aeruginosa, Acinetobacter spp., and multidrug-resistant (MDR) Enterobacteriaceae. These lessons need to be applied to our old drugs to preserve them as well and need to be put into national and international antibiotic resistance strategies. As importantly, from a regulatory perspective, new chemical entities should have a corresponding resistance suppression plan at the time of regulatory review. In this way, we can make the best of our current situation and improve future prospects. PMID:26711759

  11. Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators

    USGS Publications Warehouse

    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.

  12. Detection and differentiation of foodborne pathogenic bacteria in mung bean sprouts using field deployable label-free SERS devices.

    PubMed

    Wu, Xiaomeng; Xu, Chao; Tripp, Ralph A; Huang, Yao-wen; Zhao, Yiping

    2013-05-21

    Vancomycin functionalized silver nanorod arrays substrates were used to obtain the surface enhanced Raman scattering (SERS) signals of six foodborne pathogenic bacteria in mung bean sprouts samples using both a portable and a handheld Raman system. The silver nanorod arrays substrates were optimized to facilitate quantitative, rapid, and sensitive detection of Salmonella enterica serotype Anatum, Salmonella enterica serotype Cubana, Salmonella enterica serotype Stanley, Salmonella enteritidis, Escherichia coli O157:H7, and Staphylococcus epidermidis. Substrate optimization was achieved by varying the nanorod length and vancomycin incubation concentration. By combining these substrates with a two-step filtration process we found that the foodborne pathogenic bacteria used in this study can be identified in mung bean sprouts with a limit of detection as low as 100 CFU ml(-1) in less than 4 h using both portable and handheld Raman systems. The results show that SERS spectra can be used to differentiate between bacterial species and serotypes when chemometric methods are employed. The low detection limit and rapid detection time of this biosensing platform for foodborne pathogenic bacteria could be a valuable field detection method for the fresh produce and food processing industries.

  13. Lipoteichoic acid (LTA) and lipopolysaccharides (LPS) from periodontal pathogenic bacteria facilitate oncogenic herpesvirus infection within primary oral cells.

    PubMed

    Dai, Lu; DeFee, Michael R; Cao, Yueyu; Wen, Jiling; Wen, Xiaofei; Noverr, Mairi C; Qin, Zhiqiang

    2014-01-01

    Kaposi's sarcoma (KS) remains the most common tumor arising in patients with HIV/AIDS, and involvement of the oral cavity represents one of the most common clinical manifestations of this tumor. HIV infection incurs an increased risk for periodontal diseases and oral carriage of a variety of bacteria. Whether interactions involving pathogenic bacteria and oncogenic viruses in the local environment facilitate replication or maintenance of these viruses in the oral cavity remains unknown. In the current study, our data indicate that pretreatment of primary human oral fibroblasts with two prototypical pathogen-associated molecular patterns (PAMPs) produced by oral pathogenic bacteria-lipoteichoic acid (LTA) and lipopolysaccharide (LPS), increase KSHV entry and subsequent viral latent gene expression during de novo infection. Further experiments demonstrate that the underlying mechanisms induced by LTA and/or LPS include upregulation of cellular receptor, increasing production of reactive oxygen species (ROS), and activating intracellular signaling pathways such as MAPK and NF-κB, and all of which are closely associated with KSHV entry or gene expression within oral cells. Based on these findings, we hope to provide the framework of developing novel targeted approaches for treatment and prevention of oral KSHV infection and KS development in high-risk HIV-positive patients.

  14. Rapid species identification of seafood spoilage and pathogenic Gram-positive bacteria by MALDI-TOF mass fingerprinting.

    PubMed

    Böhme, Karola; Fernández-No, Inmaculada C; Barros-Velázquez, Jorge; Gallardo, Jose M; Cañas, Benito; Calo-Mata, Pilar

    2011-11-01

    The rapid identification of food pathogenic and spoilage bacteria is important to ensure food quality and safety. Seafood contaminated with pathogenic bacteria is one of the major causes of food intoxications, and the rapid spoilage of seafood products results in high economic losses. In this study, a collection of the main seafood pathogenic and spoilage Gram-positive bacteria was compiled, including Bacillus spp., Listeria spp., Clostridium spp., Staphylococcus spp. and Carnobacterium spp. The strains, belonging to 20 different species, were obtained from the culture collections and studied by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). A reference library was created, including the spectral fingerprints of 32 reference strains and the extracted peak lists with 10-30 peak masses. Genus-specific as well as species-specific peak masses were assigned and could serve as biomarkers for the rapid bacterial identification. Furthermore, the peak mass lists were clustered with the web-application SPECLUST to show the phyloproteomic relationships among the studied strains. Afterwards, the method was successfully applied to identify six strains isolated from seafood by comparison with the reference library. Additionally, phylogenetic analysis based on the 16S rRNA gene was carried out and contrasted with the proteomic approach. This is the first time MALDI-TOF MS fingerprinting is applied to Gram-positive bacterial identification in seafood, being a fast and accurate technique to ensure seafood quality and safety.

  15. Antibacterial Activity of Euphorbia hebecarpa Alcoholic Extracts Against Six Human Pathogenic Bacteria in Planktonic and Biofilm Forms

    PubMed Central

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2016-01-01

    Background Biofilm formation is a primary cause of considerable bacterial destruction. Objectives In an effort to combat these industrial and medical bacterial biofilm problems, our study aims to determine the antimicrobial effect of Euphorbia hebecarpa. Materials and Methods The inhibition efficiency of alcoholic extracts on the planktonic form of six pathogenic bacteria was evaluated using a disk diffusion technique. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values were determined by means of a macrobroth dilution method. The effects of the extracts on biofilms were calculated using a microtiter plate method. Results The results of the disk diffusion assay (MBC and MIC) confirmed that E. hebecarpa ethanolic extracts were more efficient than methanolic extracts in the inhibition of planktonic forms of bacteria. Also, the inhibitory effect of the extracts in a broth medium was greater than in a solid medium. Extracts of E. hebecarpa were found to inhibit biofilm formation better than demolish of biofilm and preventing metabolic activity of bacteria in biofilm structures. The greatest inhibitory effects of E. hebecarpa extracts were observed for the biofilm formation of B. cereus (92.81%). In addition, the greatest demolition was observed for the S. aureus biofilm (74.49%), and the metabolic activity decrement of this bacteria was highest (78.21%) of all the tested bacteria. Conclusions The results of this study suggest that E. hebecarpa extracts can be used to inhibit the planktonic and biofilm forms of these selected bacteria. PMID:27635214

  16. Antibacterial Activity of Euphorbia hebecarpa Alcoholic Extracts Against Six Human Pathogenic Bacteria in Planktonic and Biofilm Forms

    PubMed Central

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2016-01-01

    Background Biofilm formation is a primary cause of considerable bacterial destruction. Objectives In an effort to combat these industrial and medical bacterial biofilm problems, our study aims to determine the antimicrobial effect of Euphorbia hebecarpa. Materials and Methods The inhibition efficiency of alcoholic extracts on the planktonic form of six pathogenic bacteria was evaluated using a disk diffusion technique. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values were determined by means of a macrobroth dilution method. The effects of the extracts on biofilms were calculated using a microtiter plate method. Results The results of the disk diffusion assay (MBC and MIC) confirmed that E. hebecarpa ethanolic extracts were more efficient than methanolic extracts in the inhibition of planktonic forms of bacteria. Also, the inhibitory effect of the extracts in a broth medium was greater than in a solid medium. Extracts of E. hebecarpa were found to inhibit biofilm formation better than demolish of biofilm and preventing metabolic activity of bacteria in biofilm structures. The greatest inhibitory effects of E. hebecarpa extracts were observed for the biofilm formation of B. cereus (92.81%). In addition, the greatest demolition was observed for the S. aureus biofilm (74.49%), and the metabolic activity decrement of this bacteria was highest (78.21%) of all the tested bacteria. Conclusions The results of this study suggest that E. hebecarpa extracts can be used to inhibit the planktonic and biofilm forms of these selected bacteria.

  17. PCR primers and probes for the 16S rRNA gene of most species of pathogenic bacteria, including bacteria found in cerebrospinal fluid.

    PubMed Central

    Greisen, K; Loeffelholz, M; Purohit, A; Leong, D

    1994-01-01

    A set of broad-range PCR primers for the 16S rRNA gene in bacteria were tested, along with three series of oligonucleotide probes to detect the PCR product. The first series of probes is broad in range and consists of a universal bacterial probe, a gram-positive probe, a Bacteroides-Flavobacterium probe, and two probes for other gram-negative species. The second series was designed to detect PCR products from seven major bacterial species or groups frequently causing meningitis: Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, S. agalactiae, Escherichia coli and other enteric bacteria, Listeria monocytogenes, and Staphylococcus aureus. The third series was designed for the detection of DNA from species or genera commonly considered potential contaminants of clinical samples, including cerebrospinal fluid (CSF): Bacillus, Corynebacterium, Propionibacterium, and coagulase-negative Staphylococcus spp. The primers amplified DNA from all 124 different species of bacteria tested. Southern hybridization testing of the broad-range probes with washes containing 3 M tetramethylammonium chloride indicated that this set of probes correctly identified all but two of the 102 bacterial species tested, the exceptions being Deinococcus radiopugnans and Gardnerella vaginalis. The gram-negative and gram-positive probes hybridized to isolates of two newly characterized bacteria, Alloiococcus otitis and Rochalimaea henselii, as predicted by Gram stain characteristics. The CSF pathogen and contaminant probe sequences were compared with available sequence information and with sequencing data for 32 different species. Testing of the CSF pathogen and contaminant probes against DNA from over 60 different strains indicated that, with the exception of the coagulase-negative Staphylococcus probes, these probes provided the correct identification of bacterial species known to be found in CSF. Images PMID:7512093

  18. Using SWAT, Bacteroidales microbial source tracking markers, and fecal indicator bacteria to predict waterborne pathogen occurrence in an agricultural watershed.

    PubMed

    Frey, Steven K; Topp, Edward; Edge, Thomas; Fall, Claudia; Gannon, Victor; Jokinen, Cassandra; Marti, Romain; Neumann, Norman; Ruecker, Norma; Wilkes, Graham; Lapen, David R

    2013-10-15

    Developing the capability to predict pathogens in surface water is important for reducing the risk that such organisms pose to human health. In this study, three primary data source scenarios (measured stream flow and water quality, modelled stream flow and water quality, and host-associated Bacteroidales) are investigated within a Classification and Regression Tree Analysis (CART) framework for classifying pathogen (Escherichia coli 0157:H7, Salmonella, Campylobacter, Cryptosporidium, and Giardia) presence and absence (P/A) for a 178 km(2) agricultural watershed. To provide modelled data, a Soil Water Assessment Tool (SWAT) model was developed to predict stream flow, total suspended solids (TSS), total N and total P, and fecal indicator bacteria loads; however, the model was only successful for flow and total N and total P simulations, and did not accurately simulate TSS and indicator bacteria transport. Also, the SWAT model was not sensitive to an observed reduction in the cattle population within the watershed that may have resulted in significant reduction in E. coli concentrations and Salmonella detections. Results show that when combined with air temperature and precipitation, SWAT modelled stream flow and total P concentrations were useful for classifying pathogen P/A using CART methodology. From a suite of host-associated Bacteroidales markers used as independent variables in CART analysis, the ruminant marker was found to be the best initial classifier of pathogen P/A. Of the measured sources of independent variables, air temperature, precipitation, stream flow, and total P were found to be the most important variables for classifying pathogen P/A. Results indicate a close relationship between cattle pollution and pathogen occurrence in this watershed, and an especially strong link between the cattle population and Salmonella detections. PMID:24079968

  19. Non-pathogenic bacteria elicit a differential cytokine response by intestinal epithelial cell/leucocyte co-cultures

    PubMed Central

    Haller, D; Bode, C; Hammes, W; Pfeifer, A; Schiffrin, E; Blum, S

    2000-01-01

    BACKGROUND AND AIM—Intestinal epithelial cells (IEC) are thought to participate in the mucosal defence against bacteria and in the regulation of mucosal tissue homeostasis. Reactivity of IEC to bacterial signals may depend on interactions with immunocompetent cells. To address the question of whether non-pathogenic bacteria modify the immune response of the intestinal epithelium, we co-cultivated enterocyte-like CaCO-2 cells with human blood leucocytes in separate compartments of transwell cultures.
METHODS—CaCO-2/PBMC co-cultures were stimulated with non-pathogenic bacteria and enteropathogenic Escherichia coli. Expression of tumour necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-8, monocyte chemoattracting protein 1 (MCP-1), and IL-10 was studied by enzyme linked immunosorbent assays (cytokine secretion) and by semiquantitative reverse transcription-polymerase chain reaction.
RESULTS—Challenge of CaCO-2 cells with non-pathogenic E coli and Lactobacillus sakei induced expression of IL-8, MCP-1, IL-1β, and TNF-α mRNA in the presence of underlying leucocytes. Leucocyte sensitised CaCO-2 cells produced TNF-α and IL-1β whereas IL-10 was exclusively secreted by human peripheral blood mononuclear cells. CaCO-2 cells alone remained hyporesponsive to the bacterial challenge. Lactobacillus johnsonii, an intestinal isolate, showed reduced potential to induce proinflammatory cytokines but increased transforming growth factor beta mRNA in leucocyte sensitised CaCO-2 cells. TNF-α was identified as one of the early mediators involved in cellular cross talk. In the presence of leucocytes, discriminative activation of CaCO-2 cells was observed between enteropathogenic E coli and non-pathogenic bacteria.
CONCLUSION—The differential recognition of non-pathogenic bacteria by CaCO-2 cells required the presence of underlying leucocytes. These results strengthen the hypothesis that bacterial signalling at the mucosal surface is dependent on a network of

  20. Combined antibacterial activity of stingless bee (Apis mellipodae) honey and garlic (Allium sativum) extracts against standard and clinical pathogenic bacteria

    PubMed Central

    Andualem, Berhanu

    2013-01-01

    Objective To investigate the synergic antibacterial activity of garlic and tazma honey against standard and clinical pathogenic bacteria. Methods Antimicrobial activity of tazma honey, garlic and mixture of them against pathogenic bacteria were determined. Chloramphenicol and water were used as positive and negative controls, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration of antimicrobial samples were determined using standard methods. Results Inhibition zone of mixture of garlic and tazma honey against all tested pathogens was significantly (P≤0.05) greater than garlic and tazma honey alone. The diameter zone of inhibition ranged from (18±1) to (35±1) mm for mixture of garlic and tazma honey, (12±1) to (20±1) mm for tazma honey and (14±1) to (22±1) mm for garlic as compared with (10±1) to (30±1) mm for chloramphenicol. The combination of garlic and tazma honey (30-35 mm) was more significantly (P≤0.05) effective against Salmonella (NCTC 8385), Staphylococcus aureus (ATCC 25923), Lyesria moncytogenes (ATCC 19116) and Streptococcus pneumonia (ATCC 63). Results also showed considerable antimicrobial activity of garlic and tazma honey. MIC of mixture of garlic and tazma honey at 6.25% against total test bacteria was 88.9%. MIC of mixture of garlic and tazma honey at 6.25% against Gram positive and negative were 100% and 83.33%, respectively. The bactericidal activities of garlic, tazma honey, and mixture of garlic and tazma honey against all pathogenic bacteria at 6.25% concentration were 66.6%, 55.6% and 55.6%, respectively. Conclusions This finding strongly supports the claim of the local community to use the combination of tazma honey and garlic for the treatment of different pathogenic bacterial infections. Therefore, garlic in combination with tazma honey can serve as an alternative natural antimicrobial drug for the treatment of pathogenic bacterial infections. Further in vivo study is recommended to come

  1. Selection and identification of non-pathogenic bacteria isolated from fermented pickles with antagonistic properties against two shrimp pathogens.

    PubMed

    Zokaeifar, Hadi; Balcázar, José Luis; Kamarudin, Mohd Salleh; Sijam, Kamaruzaman; Arshad, Aziz; Saad, Che Roos

    2012-06-01

    In this study, potential probiotic strains were isolated from fermented pickles based on antagonistic activity against two shrimp pathogens (Vibrio harveyi and Vibrio parahaemolyticus). Two strains L10 and G1 were identified by biochemical tests, followed by16S ribosomal RNA gene sequence analysis as Bacillus subtilis, and characterized by PCR amplification of repetitive bacterial DNA elements (Rep-PCR). Subsequently, B. subtilis L10 and G1 strains were tested for antibacterial activity under different physical conditions, including culture medium, salinity, pH and temperature using the agar well diffusion assay. Among the different culture media, LB broth was the most suitable medium for antibacterial production. Both strains showed the highest level of antibacterial activity against two pathogens at 30 °C and 1.0% NaCl. Under the pH conditions, strain G1 showed the greatest activity against V. harveyi at pH 7.3-8.0 and against V. parahaemolyticus at pH 6.0-8.0, whereas strain L10 showed the greatest activity against two pathogens at pH 7.3. The cell-free supernatants of both strains were treated with four different enzymes in order to characterize the antibacterial substances against V. harveyi. The result showed considerable reduction of antibacterial activity for both strains, indicating the proteinaceous nature of the antibacterial substances. A wide range of tolerance to NaCl, pH and temperature was also recorded for both strains. In addition, both strains showed no virulence effect in juvenile shrimp Litopenaeus vannamei. On the basis of these results and safety of strains to L. vannamei, they may be considered for future challenge experiments in shrimp as a very promising alternative to the use of antibiotics. PMID:22491136

  2. Cost-effective filter materials coated with silver nanoparticles for the removal of pathogenic bacteria in groundwater.

    PubMed

    Mpenyana-Monyatsi, Lizzy; Mthombeni, Nomcebo H; Onyango, Maurice S; Momba, Maggy N B

    2012-01-01

    The contamination of groundwater sources by pathogenic bacteria poses a public health concern to communities who depend totally on this water supply. In the present study, potentially low-cost filter materials coated with silver nanoparticles were developed for the disinfection of groundwater. Silver nanoparticles were deposited on zeolite, sand, fibreglass, anion and cation resin substrates in various concentrations (0.01 mM, 0.03 mM, 0.05 mM and 0.1 mM) of AgNO(3). These substrates were characterised by SEM, EDS, TEM, particle size distribution and XRD analyses. In the first phase, the five substrates coated with various concentrations of AgNO(3) were tested against E. coli spiked in synthetic water to determine the best loading concentration that could remove pathogenic bacteria completely from test water. The results revealed that all filters were able to decrease the concentration of E. coli from synthetic water, with a higher removal efficiency achieved at 0.1 mM (21-100%) and a lower efficiency at 0.01 mM (7-50%) concentrations. The cation resin-silver nanoparticle filter was found to remove this pathogenic bacterium at the highest rate, namely 100%. In the second phase, only the best performing concentration of 0.1 mM was considered and tested against presumptive E. coli, S. typhimurium, S. dysenteriae and V. cholerae from groundwater. The results revealed the highest bacteria removal efficiency by the Ag/cation resin filter with complete (100%) removal of all targeted bacteria and the lowest by the Ag/zeolite filter with an 8% to 67% removal rate. This study therefore suggests that the filter system with Ag/cation resin substrate can be used as a potential alternative cost-effective filter for the disinfection of groundwater and production of safe drinking water.

  3. Cost-Effective Filter Materials Coated with Silver Nanoparticles for the Removal of Pathogenic Bacteria in Groundwater

    PubMed Central

    Mpenyana-Monyatsi, Lizzy; Mthombeni, Nomcebo H.; Onyango, Maurice S.; Momba, Maggy N. B.

    2012-01-01

    The contamination of groundwater sources by pathogenic bacteria poses a public health concern to communities who depend totally on this water supply. In the present study, potentially low-cost filter materials coated with silver nanoparticles were developed for the disinfection of groundwater. Silver nanoparticles were deposited on zeolite, sand, fibreglass, anion and cation resin substrates in various concentrations (0.01 mM, 0.03 mM, 0.05 mM and 0.1 mM) of AgNO3. These substrates were characterised by SEM, EDS, TEM, particle size distribution and XRD analyses. In the first phase, the five substrates coated with various concentrations of AgNO3 were tested against E. coli spiked in synthetic water to determine the best loading concentration that could remove pathogenic bacteria completely from test water. The results revealed that all filters were able to decrease the concentration of E. coli from synthetic water, with a higher removal efficiency achieved at 0.1 mM (21–100%) and a lower efficiency at 0.01 mM (7–50%) concentrations. The cation resin-silver nanoparticle filter was found to remove this pathogenic bacterium at the highest rate, namely 100%. In the second phase, only the best performing concentration of 0.1 mM was considered and tested against presumptive E. coli, S. typhimurium, S. dysenteriae and V. cholerae from groundwater. The results revealed the highest bacteria removal efficiency by the Ag/cation resin filter with complete (100%) removal of all targeted bacteria and the lowest by the Ag/zeolite filter with an 8% to 67% removal rate. This study therefore suggests that the filter system with Ag/cation resin substrate can be used as a potential alternative cost-effective filter for the disinfection of groundwater and production of safe drinking water. PMID:22470290

  4. Lab-on-a-chip modules for detection of highly pathogenic bacteria: from sample preparation to detection

    NASA Astrophysics Data System (ADS)

    Julich, S.; Kopinč, R.; Hlawatsch, N.; Moche, C.; Lapanje, A.; Gärtner, C.; Tomaso, H.

    2014-05-01

    Lab-on-a-chip systems are innovative tools for the detection and identification of microbial pathogens in human and veterinary medicine. The major advantages are small sample volume and a compact design. Several fluidic modules have been developed to transform analytical procedures into miniaturized scale including sampling, sample preparation, target enrichment, and detection procedures. We present evaluation data for single modules that will be integrated in a chip system for the detection of pathogens. A microfluidic chip for purification of nucleic acids was established for cell lysis using magnetic beads. This assay was evaluated with spiked environmental aerosol and swab samples. Bacillus thuringiensis was used as simulant for Bacillus anthracis, which is closely related but non-pathogenic for humans. Stationary PCR and a flow-through PCR chip module were investigated for specific detection of six highly pathogenic bacteria. The conventional PCR assays could be transferred into miniaturized scale using the same temperature/time profile. We could demonstrate that the microfluidic chip modules are suitable for the respective purposes and are promising tools for the detection of bacterial pathogens. Future developments will focus on the integration of these separate modules to an entire lab-on-a-chip system.

  5. Evaluation of the use of PCR and reverse transcriptase PCR for detection of pathogenic bacteria in biosolids from anaerobic digestors and aerobic composters.

    PubMed

    Burtscher, Carola; Wuertz, Stefan

    2003-08-01

    A PCR-based method and a reverse transcriptase PCR (RT-PCR)-based method were developed for the detection of pathogenic bacteria in organic waste, using Salmonella spp., Listeria monocytogenes, Yersinia enterocolitica, and Staphylococcus aureus as model organisms. In seeded organic waste samples, detection limits of less than 10 cells per g of organic waste were achieved after one-step enrichment of bacteria, isolation, and purification of DNA or RNA before PCR or RT-PCR amplification. To test the reproducibility and reliability of the newly developed methods, 46 unseeded samples were collected from diverse aerobic (composting) facilities and anaerobic digestors and analyzed by both culture-based classical and newly developed PCR-based procedures. No false-positive but some false-negative results were generated by the PCR- or RT-PCR-based methods after one-step enrichment when compared to the classical detection methods. The results indicated that the level of activity of the tested bacteria in unseeded samples was very low compared to that of freshly inoculated cells, preventing samples from reaching the cell density required for PCR-based detection after one-step enrichment. However, for Salmonella spp., a distinct PCR product could be obtained for all 22 nonamended samples that tested positive for Salmonella spp. by the classical detection procedure when a selective two-step enrichment (20 h in peptone water at 37 degrees C and 24 h in Rappaport Vassiliadis medium at 43 degrees C) was performed prior to nucleic acid extraction and PCR. Hence, the classical procedure was shortened, since cell plating and further differentiation of isolated colonies can be omitted, substituted for by highly sensitive and reliable detection based on nucleic acid extraction and PCR. Similarly, 2 of the 22 samples in which Salmonella spp. were detected also tested positive for Listeria monocytogenes according to a two-step enrichment procedure followed by PCR, compared to 3 samples

  6. Antimicrobial activities of commercial essential oils and their components against food-borne pathogens and food spoilage bacteria.

    PubMed

    Mith, Hasika; Duré, Rémi; Delcenserie, Véronique; Zhiri, Abdesselam; Daube, Georges; Clinquart, Antoine

    2014-07-01

    This study was undertaken to determine the in vitro antimicrobial activities of 15 commercial essential oils and their main components in order to pre-select candidates for potential application in highly perishable food preservation. The antibacterial effects against food-borne pathogenic bacteria (Listeria monocytogenes, Salmonella Typhimurium, and enterohemorrhagic Escherichia coli O157:H7) and food spoilage bacteria (Brochothrix thermosphacta and Pseudomonas fluorescens) were tested using paper disk diffusion method, followed by determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Most of the tested essential oils exhibited antimicrobial activity against all tested bacteria, except galangal oil. The essential oils of cinnamon, oregano, and thyme showed strong antimicrobial activities with MIC ≥ 0.125 μL/mL and MBC ≥ 0.25 μL/mL. Among tested bacteria, P. fluorescens was the most resistant to selected essential oils with MICs and MBCs of 1 μL/mL. The results suggest that the activity of the essential oils of cinnamon, oregano, thyme, and clove can be attributed to the existence mostly of cinnamaldehyde, carvacrol, thymol, and eugenol, which appear to possess similar activities against all the tested bacteria. These materials could be served as an important natural alternative to prevent bacterial growth in food products. PMID:25473498

  7. Antimicrobial activities of commercial essential oils and their components against food-borne pathogens and food spoilage bacteria

    PubMed Central

    Mith, Hasika; Duré, Rémi; Delcenserie, Véronique; Zhiri, Abdesselam; Daube, Georges; Clinquart, Antoine

    2014-01-01

    This study was undertaken to determine the in vitro antimicrobial activities of 15 commercial essential oils and their main components in order to pre-select candidates for potential application in highly perishable food preservation. The antibacterial effects against food-borne pathogenic bacteria (Listeria monocytogenes, Salmonella Typhimurium, and enterohemorrhagic Escherichia coli O157:H7) and food spoilage bacteria (Brochothrix thermosphacta and Pseudomonas fluorescens) were tested using paper disk diffusion method, followed by determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Most of the tested essential oils exhibited antimicrobial activity against all tested bacteria, except galangal oil. The essential oils of cinnamon, oregano, and thyme showed strong antimicrobial activities with MIC ≥ 0.125 μL/mL and MBC ≥ 0.25 μL/mL. Among tested bacteria, P. fluorescens was the most resistant to selected essential oils with MICs and MBCs of 1 μL/mL. The results suggest that the activity of the essential oils of cinnamon, oregano, thyme, and clove can be attributed to the existence mostly of cinnamaldehyde, carvacrol, thymol, and eugenol, which appear to possess similar activities against all the tested bacteria. These materials could be served as an important natural alternative to prevent bacterial growth in food products. PMID:25473498

  8. Antimicrobial activities of commercial essential oils and their components against food-borne pathogens and food spoilage bacteria.

    PubMed

    Mith, Hasika; Duré, Rémi; Delcenserie, Véronique; Zhiri, Abdesselam; Daube, Georges; Clinquart, Antoine

    2014-07-01

    This study was undertaken to determine the in vitro antimicrobial activities of 15 commercial essential oils and their main components in order to pre-select candidates for potential application in highly perishable food preservation. The antibacterial effects against food-borne pathogenic bacteria (Listeria monocytogenes, Salmonella Typhimurium, and enterohemorrhagic Escherichia coli O157:H7) and food spoilage bacteria (Brochothrix thermosphacta and Pseudomonas fluorescens) were tested using paper disk diffusion method, followed by determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Most of the tested essential oils exhibited antimicrobial activity against all tested bacteria, except galangal oil. The essential oils of cinnamon, oregano, and thyme showed strong antimicrobial activities with MIC ≥ 0.125 μL/mL and MBC ≥ 0.25 μL/mL. Among tested bacteria, P. fluorescens was the most resistant to selected essential oils with MICs and MBCs of 1 μL/mL. The results suggest that the activity of the essential oils of cinnamon, oregano, thyme, and clove can be attributed to the existence mostly of cinnamaldehyde, carvacrol, thymol, and eugenol, which appear to possess similar activities against all the tested bacteria. These materials could be served as an important natural alternative to prevent bacterial growth in food products.

  9. Correlation of Metabolic Variables with the Number of ORFs in Human Pathogenic and Phylogenetically Related Non- or Less-Pathogenic Bacteria.

    PubMed

    Brambila-Tapia, Aniel Jessica Leticia; Poot-Hernández, Augusto Cesar; Garcia-Guevara, Jose Fernando; Rodríguez-Vázquez, Katya

    2016-06-01

    To date, a few works have performed a correlation of metabolic variables in bacteria; however specific correlations with these variables have not been reported. In this work, we included 36 human pathogenic bacteria and 18 non- or less-pathogenic-related bacteria and obtained all metabolic variables, including enzymes, metabolic pathways, enzymatic steps and specific metabolic pathways, and enzymatic steps of particular metabolic processes, from a reliable metabolic database (KEGG). Then, we correlated the number of the open reading frames (ORF) with these variables and with the proportions of these variables, and we observed a negative correlation with the proportion of enzymes (r = -0.506, p < 0.0001), metabolic pathways (r = -0.871, p < 00.0001), enzymatic reactions (r = -0.749, p < 00.0001), and with the proportions of central metabolism variables as well as a positive correlation with the proportions of multistep reactions (r = 0.650, p < 00.0001) and secondary metabolism variables. The proportion of multifunctional reactions (r: -0.114, p = 0.41) and the proportion of enzymatic steps (r: -0.205, p = 0.14) did not present a significant correlation. These correlations indicate that as the size of a genome (measured in the number of ORFs) increases, the proportion of genes that encode enzymes significantly diminishes (especially those related to central metabolism), suggesting that when essential metabolic pathways are complete, an increase in the number of ORFs does not require a similar increase in the metabolic pathways and enzymes, but only a slight increase is sufficient to cope with a large genome.

  10. Correlation of Metabolic Variables with the Number of ORFs in Human Pathogenic and Phylogenetically Related Non- or Less-Pathogenic Bacteria.

    PubMed

    Brambila-Tapia, Aniel Jessica Leticia; Poot-Hernández, Augusto Cesar; Garcia-Guevara, Jose Fernando; Rodríguez-Vázquez, Katya

    2016-06-01

    To date, a few works have performed a correlation of metabolic variables in bacteria; however specific correlations with these variables have not been reported. In this work, we included 36 human pathogenic bacteria and 18 non- or less-pathogenic-related bacteria and obtained all metabolic variables, including enzymes, metabolic pathways, enzymatic steps and specific metabolic pathways, and enzymatic steps of particular metabolic processes, from a reliable metabolic database (KEGG). Then, we correlated the number of the open reading frames (ORF) with these variables and with the proportions of these variables, and we observed a negative correlation with the proportion of enzymes (r = -0.506, p < 0.0001), metabolic pathways (r = -0.871, p < 00.0001), enzymatic reactions (r = -0.749, p < 00.0001), and with the proportions of central metabolism variables as well as a positive correlation with the proportions of multistep reactions (r = 0.650, p < 00.0001) and secondary metabolism variables. The proportion of multifunctional reactions (r: -0.114, p = 0.41) and the proportion of enzymatic steps (r: -0.205, p = 0.14) did not present a significant correlation. These correlations indicate that as the size of a genome (measured in the number of ORFs) increases, the proportion of genes that encode enzymes significantly diminishes (especially those related to central metabolism), suggesting that when essential metabolic pathways are complete, an increase in the number of ORFs does not require a similar increase in the metabolic pathways and enzymes, but only a slight increase is sufficient to cope with a large genome. PMID:26920870

  11. Bioactivity determination of methanol and water extracts for roots and leaves of Kenyan Psidium guajava L landraces against pathogenic bacteria.

    PubMed

    Liharaka Kidaha, Mercy; Alakonya, Amos Emitati; Nyende, Aggrey Benard

    2013-01-01

    Guava (Psidium guajava L) is native to South America and exists as both wild and cultivated. Guava has been used as a source of food and raw materials for pharmaceuticals. The aim of this study was to determine bioactivity of methanol and water extracts from root and leaves of Kenyan guava landraces against selected pathogenic bacteria. Study samples were collected from Western and South Coast of Kenya. One hundred grams of leaf and root ground powders were used for sequential extraction using methanol and water. Extracts were evaporated and 0.2gms dissolved using the extraction solvent and tested against gram positive (Staphylococcus aureus, Bacillus subtilis) and negative bacteria (Escherichia coli). Data on inhibition zone was taken in mm and analyzed at 95% confidence interval. Extracts from Western region had significant inhibition compared to Coastal region. The two regions have different climatic conditions that result in these plants having different compounds even though they are the same species. Roots had higher inhibition compared to the leaves as they contain high levels of tannins compared to leaves. Water as an extracting solvent had higher inhibition than methanol as it is more polar and it absorbs more bioactive compounds. S. aureus was most inhibited followed by E. coli and B. subtilis respectively. There was no significant difference between the gram positive and negative bacteria. Remarkably, some methanol and water root extracts had significant inhibition against bacteria when compared to some commercial antibiotics used. Results of this study indicate that Kenyan guava roots from Western Kenya extracted with methanol and water have a potential to be used as a source of active compounds in treatment of gram positive and gram negative bacteria pathogens. PMID:25674419

  12. Bioactivity determination of methanol and water extracts for roots and leaves of Kenyan Psidium guajava L landraces against pathogenic bacteria.

    PubMed

    Liharaka Kidaha, Mercy; Alakonya, Amos Emitati; Nyende, Aggrey Benard

    2013-01-01

    Guava (Psidium guajava L) is native to South America and exists as both wild and cultivated. Guava has been used as a source of food and raw materials for pharmaceuticals. The aim of this study was to determine bioactivity of methanol and water extracts from root and leaves of Kenyan guava landraces against selected pathogenic bacteria. Study samples were collected from Western and South Coast of Kenya. One hundred grams of leaf and root ground powders were used for sequential extraction using methanol and water. Extracts were evaporated and 0.2gms dissolved using the extraction solvent and tested against gram positive (Staphylococcus aureus, Bacillus subtilis) and negative bacteria (Escherichia coli). Data on inhibition zone was taken in mm and analyzed at 95% confidence interval. Extracts from Western region had significant inhibition compared to Coastal region. The two regions have different climatic conditions that result in these plants having different compounds even though they are the same species. Roots had higher inhibition compared to the leaves as they contain high levels of tannins compared to leaves. Water as an extracting solvent had higher inhibition than methanol as it is more polar and it absorbs more bioactive compounds. S. aureus was most inhibited followed by E. coli and B. subtilis respectively. There was no significant difference between the gram positive and negative bacteria. Remarkably, some methanol and water root extracts had significant inhibition against bacteria when compared to some commercial antibiotics used. Results of this study indicate that Kenyan guava roots from Western Kenya extracted with methanol and water have a potential to be used as a source of active compounds in treatment of gram positive and gram negative bacteria pathogens.

  13. A simplified experimental model for clearance of some pathogenic bacteria using common bacterivorous ciliated spp. in Tigris river

    NASA Astrophysics Data System (ADS)

    Ali, Talib Hassan; Saleh, Dhuha Saad

    2014-03-01

    Bacteria-specific uptake rates of three different protozoan taxa on a pure and mixed bacterial community was studied by means of a simplified and functionally reproducible experimental model. The bacterial species Shigella flexneri, Escherichia coli and Salmonella typhi were isolated and classified from stool samples of patients suffering from diarrhea. Paramecium caudatum, Tetrahymena pyriformis and Halteria grandinella, free living ciliate Protozoans, were isolated and identified from Tigris river water. Pure and mixed ( E. coli + S. typhi), ( E. coli + Sh. flexneri) bacterial cultures were used with each ciliate genera to evaluate the following: predator duplication rate, prey reduction rate, clearance rate and net grazing rate. We used selective lactose fermentation phenomena of enteric bacteria on MacConkey medium for the quantification of bacteria cultural characteristics. The final bacteria concentration was reduced by growing protozoa of 98-99.9 % compared to protozoa-free controls. It showed that Tetrahymena pyriformis had the highest duplication rate (4.13 time/day) in both types of cultures (pure and mixed), followed by Paramecium caudatum and Halteria grandinella, respectively. Paramecium caudatum had the highest rate of ingestion in both types of cultures (26 × 103 bacteria/organism/hr) and yielded the longest time required for 90 % bacterial reduction in a pure suspension of S. typhi (166 h). Clearance rates of pathogenic bacteria by ciliates ranged between 106 nanoliter/organism/h by P. caudatum to S. typhi and 1.92 nanoliter/organism/h seen in T. pyriformis in ( E. coli + S. typhi) mixed culture. We used aquatic experimental microcosms under controlled conditions to explore bacteria-dependent ciliate growth and examined whether these ciliates could discriminate between equally sized bacterial preys in a mixture.

  14. [Pathogenic bacteria dissemination by ants (Hymenoptera: Formicidae) in two hospitals in northeast Brazil].

    PubMed

    Fontana, Renato; Wetler, Rita M da C; Aquino, Renata S S; Andrioli, João L; Queiroz, Guilherme R G; Ferreira, Sônia L; Nascimento, Ivan C do; Delabie, Jacques H C

    2010-01-01

    Nosocomial infections bring a high risk to the health of hospital patients and employees. Ants are common organisms in Brazilian hospitals, where they can act as dispersers of opportunistic microorganisms in places they forage. The occurrence of multi-resistant bacteria carried by ants was analyzed in two public hospitals (HA and HB) in southeastern Bahia, Brazil. In these two hospitals 132 workers belonging to three ant species were collected. The bacteria associated to these ants were identified and their susceptibility to antibiotics was evaluated. More than half (57.3%) of ants collected in HA were associated with some kind of bacteria, with 26.7% of them being opportunist bacteria, while 84,2% of the ants from HB presented associated bacteria growth, with 61.4% of them being opportunist bacteria. Twenty four species of bacteria were isolated. The Gram-positive bacilli of the genus Bacillus were the most frequent, followed by the Gram-positive cocci, Gram-negative bacilli (family Enterobacteriaceae) and Gram-negative non-fermenters bacilli. The profile of sensitivity of the bacterial isolates to drugs pointed out the existence of multi-resistant isolates carried by ants. For the first time, are reported cases of the same bacterial resistant isolates taken form homospecific ant workers that point out the importance of ants to bacteria dissemination and proliferation in a hospital. Our results suggest that the risk of contamination presented by these ants is similar to the one of any other mechanical vector of bacterial dissemination.

  15. Diversity and natural functions of antibiotices produced by beneficial and pathogenic soil bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil and plant-associated environments harbor numerous bacterial species that produce antibiotic metabolites. Many of these bacteria have been exploited for the discovery of clinical antibiotics and other therapeutics. In the field of plant pathology, antibiotic-producing bacteria are used as a reso...

  16. A recombinant horseshoe crab plasma lectin recognizes specific pathogen-associated molecular patterns of bacteria through rhamnose.

    PubMed

    Ng, Sim-Kun; Huang, Yu-Tsyr; Lee, Yuan-Chuan; Low, Ee-Ling; Chiu, Cheng-Hsun; Chen, Shiu-Ling; Mao, Liang-Chi; Chang, Margaret Dah-Tsyr

    2014-01-01

    Horseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs), yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL) in an Escherichia coli system. Interestingly, rHPL bound not only to bacteria and LPSs like the native HPL but also to selective medically important pathogens isolated from clinical specimens, such as Gram-negative Pseudomonas aeruginosa and Klebsiella pneumoniae and Gram-positive Streptococcus pneumoniae serotypes. The binding was demonstrated to occur through a specific molecular interaction with rhamnose in pathogen-associated molecular patterns (PAMPs) on the bacterial surface. Additionally, rHPL inhibited the growth of P. aeruginosa PAO1 in a concentration-dependent manner. The results suggest that a specific protein-glycan interaction between rHPL and rhamnosyl residue may further facilitate development of novel diagnostic and therapeutic strategies for microbial pathogens. PMID:25541995

  17. Recyclable Photo-Thermal Nano-Aggregates of Magnetic Nanoparticle Conjugated Gold Nanorods for Effective Pathogenic Bacteria Lysis.

    PubMed

    Ramasamy, Mohankandhasamy; Kim, Sanghyo; Lee, Su Seong; Yi, Dong Kee

    2016-01-01

    We describe the nucleophilic hybridization technique for fabricating magnetic nanoparticle (MNP) around gold nanorod (AuNR) for desired photo-thermal lysis on pathogenic bacteria. From the electromagnetic energy conversion into heat to the surrounding medium, a significant and quicker temperature rise was noted after light absorption on nanohybrids, at a controlled laser light output and optimum nanoparticle concentration. We observed a similar photo-thermal pattern for more than three times for the same material up on repeated magnetic separation. Regardless of the cell wall nature, superior pathogenic cell lysis has been observed for the bacteria suspensions of individual and mixed samples of Salmonella typhi (S.typhi) and Bacillus subtilis (B.subtilis) by the photo-heated nanoparticles. The synthesis of short gold nanorod, conjugation with magnetic nanoparticle and its subsequent laser exposure provides a rapid and reiterated photo-thermal effect with enhanced magnetic separation for efficient bactericidal application in water samples. Resultant novel properties of the nano-aggregates makes them a candidate to be used for a rapid, effective, and re-iterated photo-thermal agent against a wide variety of pathogens to attain microbe free water. PMID:27398487

  18. Food-borne zoonotic pathogens and antimicrobial resistance of indicator bacteria in urban wild boars in Barcelona, Spain.

    PubMed

    Navarro-Gonzalez, Nora; Casas-Díaz, Encarna; Porrero, Concepción M; Mateos, Ana; Domínguez, Lucas; Lavín, Santiago; Serrano, Emmanuel

    2013-12-27

    Wildlife is increasingly abundant in urban environments, but little is known about the zoonotic pathogens carried by these populations. Urban wild boars are of particular concern because this species is well-known as a pathogen reservoir, and thus, we studied selected zoonotic pathogens in urban wild boars in Barcelona, Spain (n=41). Salmonella enterica was found in 5.00% (95% CI 0.61-16.91) and Campylobacter coli in 4.88% (95% CI 0.6-16.53) of the animals. E. coli O157:H7 and C. jejuni were not found. Other thermophilic Campylobacter were moderately prevalent (19.51%, 95% CI 8.82-34.87). Additionally, we screened for antimicrobial resistance in indicator bacteria: resistance was most frequent in Enterococcus faecium (95% of the isolates were resistant to at least one antimicrobial agent), followed by Enterococcus faecalis (50%) and Escherichia coli (10%). For the first time resistance to linezolid in bacteria carried by wildlife is reported. These findings pose a concern for public health, and thus, further research is needed on wildlife in urban environments.

  19. Recyclable Photo-Thermal Nano-Aggregates of Magnetic Nanoparticle Conjugated Gold Nanorods for Effective Pathogenic Bacteria Lysis.

    PubMed

    Ramasamy, Mohankandhasamy; Kim, Sanghyo; Lee, Su Seong; Yi, Dong Kee

    2016-01-01

    We describe the nucleophilic hybridization technique for fabricating magnetic nanoparticle (MNP) around gold nanorod (AuNR) for desired photo-thermal lysis on pathogenic bacteria. From the electromagnetic energy conversion into heat to the surrounding medium, a significant and quicker temperature rise was noted after light absorption on nanohybrids, at a controlled laser light output and optimum nanoparticle concentration. We observed a similar photo-thermal pattern for more than three times for the same material up on repeated magnetic separation. Regardless of the cell wall nature, superior pathogenic cell lysis has been observed for the bacteria suspensions of individual and mixed samples of Salmonella typhi (S.typhi) and Bacillus subtilis (B.subtilis) by the photo-heated nanoparticles. The synthesis of short gold nanorod, conjugation with magnetic nanoparticle and its subsequent laser exposure provides a rapid and reiterated photo-thermal effect with enhanced magnetic separation for efficient bactericidal application in water samples. Resultant novel properties of the nano-aggregates makes them a candidate to be used for a rapid, effective, and re-iterated photo-thermal agent against a wide variety of pathogens to attain microbe free water.

  20. A recombinant horseshoe crab plasma lectin recognizes specific pathogen-associated molecular patterns of bacteria through rhamnose.

    PubMed

    Ng, Sim-Kun; Huang, Yu-Tsyr; Lee, Yuan-Chuan; Low, Ee-Ling; Chiu, Cheng-Hsun; Chen, Shiu-Ling; Mao, Liang-Chi; Chang, Margaret Dah-Tsyr

    2014-01-01

    Horseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs), yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL) in an Escherichia coli system. Interestingly, rHPL bound not only to bacteria and LPSs like the native HPL but also to selective medically important pathogens isolated from clinical specimens, such as Gram-negative Pseudomonas aeruginosa and Klebsiella pneumoniae and Gram-positive Streptococcus pneumoniae serotypes. The binding was demonstrated to occur through a specific molecular interaction with rhamnose in pathogen-associated molecular patterns (PAMPs) on the bacterial surface. Additionally, rHPL inhibited the growth of P. aeruginosa PAO1 in a concentration-dependent manner. The results suggest that a specific protein-glycan interaction between rHPL and rhamnosyl residue may further facilitate development of novel diagnostic and therapeutic strategies for microbial pathogens.

  1. Dual Targeting of Intracellular Pathogenic Bacteria with a Cleavable Conjugate of Kanamycin and an Antibacterial Cell-Penetrating Peptide.

    PubMed

    Brezden, Anna; Mohamed, Mohamed F; Nepal, Manish; Harwood, John S; Kuriakose, Jerrin; Seleem, Mohamed N; Chmielewski, Jean

    2016-08-31

    Bacterial infection caused by intracellular pathogens, such as Mycobacterium, Salmonella, and Brucella, is a burgeoning global health epidemic that necessitates urgent action. However, the therapeutic value of a number of antibiotics, including aminoglycosides, against intracellular pathogenic bacteria is compromised due to their inability to traverse eukaryotic membranes. For this significant problem to be addressed, a cleavable conjugate of the antibiotic kanamycin and a nonmembrane lytic, broad-spectrum antimicrobial peptide with efficient mammalian cell penetration, P14LRR, was prepared. This approach allows kanamycin to enter mammalian cells as a conjugate linked via a tether that breaks down in the reducing environment within cells. Potent antimicrobial activity of the P14KanS conjugate was demonstrated in vitro, and this reducible conjugate effectively cleared intracellular pathogenic bacteria within macrophages more potently than that of a conjugate lacking the disulfide moiety. Notably, successful clearance of Mycobacterium tuberculosis within macrophages was observed with the dual antibiotic conjugate, and Salmonella levels were significantly reduced in an in vivo Caenorhabditis elegans model.

  2. A Recombinant Horseshoe Crab Plasma Lectin Recognizes Specific Pathogen-Associated Molecular Patterns of Bacteria through Rhamnose

    PubMed Central

    Ng, Sim-Kun; Huang, Yu-Tsyr; Lee, Yuan-Chuan; Low, Ee-Ling; Chiu, Cheng-Hsun; Chen, Shiu-Ling; Mao, Liang-Chi; Chang, Margaret Dah-Tsyr

    2014-01-01

    Horseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs), yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL) in an Escherichia coli system. Interestingly, rHPL bound not only to bacteria and LPSs like the native HPL but also to selective medically important pathogens isolated from clinical specimens, such as Gram-negative Pseudomonas aeruginosa and Klebsiella pneumoniae and Gram-positive Streptococcus pneumoniae serotypes. The binding was demonstrated to occur through a specific molecular interaction with rhamnose in pathogen-associated molecular patterns (PAMPs) on the bacterial surface. Additionally, rHPL inhibited the growth of P. aeruginosa PAO1 in a concentration-dependent manner. The results suggest that a specific protein-glycan interaction between rHPL and rhamnosyl residue may further facilitate development of novel diagnostic and therapeutic strategies for microbial pathogens. PMID:25541995

  3. Fabrication, characterization and antibacterial effect of novel electrospun TiO2 nanorods on a panel of pathogenic bacteria.

    PubMed

    Hassan, M Shamshi; Amna, Touseef; Mishra, Amrita; Yun, Soon-Il; Kim, Hyun-Chel; Kim, Hak-Yong; Khil, Myung-Seob

    2012-06-01

    This study is aimed at the synthesis and characterization of novel Titania nanorods by sol-gel electrospinning technique. The physicochemical properties of the synthesized nanorods were determined by FE-SEM, EDX, TEM, TGA and XRD. We investigated the photocatalytic activity of Titania nanorods for degrading Rhodamine 6G dye and discussed the antibacterial activity and interaction mechanism against four pathogenic bacteria viz., S. aureus, E. coli, S. typhimurium and K. pneumoniae by taking five different concentrations (5-45 microg/mL). The antibacterial effect of electrospun Titania nanorods was tested both in liquid culture and on agar plates. Our investigation reveals that the lowest concentration of Titania nanorods solution inhibiting the growth of microbial strain was found to be 5 microg/mL for all the tested pathogens. The photocatalytic activity of TiO2 nanorods showed better performance for dye degradation than commercially available P25. Moreover, Bio-TEM examination demonstrated that the exposure of the selected microbial strains to the Titania nanorods led to disruption of the cell membranes and leakage of the cytoplasm which cause bacteria to die eventually. Our results point the oxidative attack from exterior to the interior of the bacteria by hydroxyl radicals as the primary mechanism of photocatalytic inactivation.

  4. Development of a DNA macroarray for simultaneous detection of multiple foodborne pathogenic bacteria in fresh chicken meat.

    PubMed

    Kupradit, Chanida; Rodtong, Sureelak; Ketudat-Cairns, Mariena

    2013-12-01

    A DNA macroarray was developed to provide the ability to detect multiple foodborne pathogens in fresh chicken meat. Probes targeted to the 16S rRNA and genus- and species-specific genes, including fimY, ipaH, prfA, and uspA, were selected for the specific detection of Salmonella spp., Shigella spp., Listeria monocytogenes, and Escherichia coli, respectively. The combination of target gene amplification by PCR and a DNA macroarray in our system was able to distinguish all target bacteria from pure cultures with a detection sensitivity of 10⁵ c.f.u. ml⁻¹. The DNA macroarray was also applied to 10 fresh chicken meat samples. The assay validation demonstrated that by combining the enrichment steps for the target bacteria and the DNA macroarray, all 4 target bacteria could be detected simultaneously from the fresh chicken samples. The sensitivity of L. monocytogenes and Shigella boydii detection in the fresh chicken samples was at least 10 and 3 c.f.u. of the initial contamination in 25 g samples, respectively. The advantages of our developed protocol are high accuracy and time reduction when compared to conventional culture. The macroarray developed in our investigation was cost effective compared to modern oligonucleotide microarray techniques because there was no expensive equipment required for the detection of multiple foodborne pathogens.

  5. Occurrence of potentially pathogenic bacteria on the hands of hospital patients before and after the introduction of patient hand disinfection.

    PubMed

    Hedin, Göran; Blomkvist, Annika; Janson, Marianne; Lindblom, Anders

    2012-10-01

    The leading cause of nosocomial infections and spread of multiresistant bacteria is considered to be the failure of healthcare workers to perform appropriate hand hygiene. The role of the hands of hospital patients in the spread of infection has received little attention. The aim of the present study was to investigate the occurrence of potentially pathogenic bacteria on the patients' hands. Quantitative cultures were repeatedly taken from the fingertips of patients at a rehabilitation clinic before and after an intervention in which patient hand disinfection was introduced and promoted. Before the intervention, the occurrence on the hands of Escherichia coli, Klebsiella spp., enterococci, Staphylococcus aureus and yeast was a common finding. The colony counts of S. aureus were often higher than the counts of other organisms. After the intervention, the level of hand contamination was lower. The difference was statistically significant (p < 0.05) concerning Enterobacteriaceae, both when the patients were resting and at lunch time, for enterococci and total bacterial counts at lunch time, and for yeast when they were resting. Concerning S. aureus, the difference was not statistically significant, neither while resting nor at lunch time. The role of the patients in the spread of pathogenic bacteria merits more discussion. PMID:22958288

  6. HecA, a member of a class of adhesins produced by diverse pathogenic bacteria, contributes to the attachment, aggregation, epidermal cell killing, and virulence phenotypes of Erwinia chrysanthemi EC16 on Nicotiana clevelandii seedlings

    PubMed Central

    Rojas, Clemencia M.; Ham, Jong Hyun; Deng, Wen-Ling; Doyle, Jeff J.; Collmer, Alan

    2002-01-01

    Erwinia chrysanthemi is representative of a broad class of bacterial pathogens that are capable of inducing necrosis in plants. The E. chrysanthemi EC16 hecA gene predicts a 3,850-aa member of the Bordetella pertussis filamentous hemagglutinin family of adhesins. A hecA∷Tn7 mutant was reduced in virulence on Nicotiana clevelandii seedlings after inoculation without wounding. Epifluorescence and confocal laser-scanning microscopy observations of hecA and wild-type cells expressing the green fluorescent protein revealed that the mutant is reduced in its ability to attach and then form aggregates on leaves and to cause an aggregate-associated killing of epidermal cells. Cell killing also depended on production of the major pectate lyase isozymes and the type II, but not the type III, secretion pathway in E. chrysanthemi. HecA homologs were found in bacterial pathogens of plants and animals and appear to be unique to pathogens and universal in necrogenic plant pathogens. Phylogenetic comparison of the conserved two-partner secretion domains in the proteins and the 16S rRNA sequences in respective bacteria revealed the two datasets to be fundamentally incongruent, suggesting horizontal acquisition of these genes. Furthermore, hecA and its two homologs in Yersinia pestis had a G+C content that was 10% higher than that of their genomes and similar to that of plant pathogenic Ralstonia, Xylella, and Pseudomonas spp. Our data suggest that filamentous hemagglutinin-like adhesins are broadly important virulence factors in both plant and animal pathogens. PMID:12271135

  7. Pathogenic bacteria and microbial-source tracking markers in Brandywine Creek Basin, Pennsylvania and Delaware, 2009-10

    USGS Publications Warehouse

    Duris, Joseph W.; Reif, Andrew G.; Olson, Leif E.; Johnson, Heather E.

    2011-01-01

    The City of Wilmington, Delaware, is in the downstream part of the Brandywine Creek Basin, on the main stem of Brandywine Creek. Wilmington uses this stream, which drains a mixed-land-use area upstream, for its main drinking-water supply. Because the stream is used for drinking water, Wilmington is in need of information about the occurrence and distribution of specific fecally derived pathogenic bacteria (disease-causing bacteria) and their relations to commonly measured fecal-indicator bacteria (FIB), as well as information regarding the potential sources of the fecal pollution and pathogens in the basin. This study focused on five routinely sampled sites within the basin, one each on the West Branch and the East Branch of Brandywine Creek and at three on the main stem below the confluence of the West and East Branches. These sites were sampled monthly for 1 year. Targeted event samples were collected on two occasions during high flow and two occasions during normal flow. On the basis of this study, high flows in the Brandywine Creek Basin were related to increases in FIB densities, and in the frequency of selected pathogen and source markers, in the West Branch and main stem of Brandywine Creek, but not in the East Branch. Water exceeding the moderate fullbody-contact single-sample recreational water-quality criteria (RWQC) for Escherichia coli (E. coli) was more likely to contain selected markers for pathogenic E. coli (eaeA,stx1, and rfbO157 gene markers) and bovine fecal sources (E. hirae and LTIIa gene markers), whereas samples exceeding the enterococci RWQC were more likely to contain the same pathogenic markers but also were more likely to carry a marker indicative of human source (esp gene marker). On four sample dates, during high flow between October and March, the West Branch was the only observed potential contributor of selected pathogen and bovine source markers to the main stem of Brandywine Creek. Indeed, the stx2 marker, which indicates a highly

  8. Comparison of inoculation methods for characterizing relative aggressiveness of two soybean sudden-death syndrome pathogens, Fusarium virguliforme and F. tucumaniae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium tucumaniae and F. virguliforme are the primary etiological agents of sudden-death syndrome (SDS) of soybean in Argentina and the United States, respectively. Five isolates of F. tucumaniae and four of F. virguliforme were tested for pathogenicity to soybeans, by comparing a toothpick method...

  9. Experimental inoculation of specific pathogen free broiler chickens with a thyroid homogenate, containing chicken astrovirus, which was collected from broiler chickens with runting-stunting syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thyroid glands were collected from field broiler chickens with clinical signs and lesions of Runting-Stunting Syndrome (RSS), submitted for histopathology and processed for polymerase chain reaction (PCR) testing using chicken Astrovirus primers. One-day-old White Rock specific pathogen free (SPF) ...

  10. Highly active modulators of indole signaling alter pathogenic behaviors in Gram-negative and Gram-positive bacteria.

    PubMed

    Minvielle, Marine J; Eguren, Kristen; Melander, Christian

    2013-12-16

    Indole is a universal signal that regulates various bacterial behaviors, such as biofilm formation and antibiotic resistance. To generate mechanistic probes of indole signaling and control indole-mediated pathogenic phenotypes in both Gram-positive and Gram-negative bacteria, we have investigated the use of desformylflustrabromine (dFBr) derivatives to generate highly active indole mimetics. We have developed non-microbicidal dFBr derivatives that are 27-2000 times more active than indole in modulating biofilm formation, motility, acid resistance, and antibiotic resistance. The activity of these analogues parallels indole, because they are dependent on temperature, the enzyme tryptophanase TnaA, and the transcriptional regulator SdiA. This investigation demonstrates that molecules based on the dFBr scaffold can alter pathogenic behaviors by mimicking indole-signaling pathways.

  11. Plant pathogenic bacteria target the actin microfilament network involved in the trafficking of disease defense components.

    PubMed

    Jelenska, Joanna; Kang, Yongsung; Greenberg, Jean T

    2014-01-01

    Cells of infected organisms transport disease defense-related molecules along actin filaments to deliver them to their sites of action to combat the pathogen. To accommodate higher demand for intracellular traffic, plant F-actin density increases transiently during infection or treatment of Arabidopsis with pathogen-associated molecules. Many animal and plant pathogens interfere with actin polymerization and depolymerization to avoid immune responses. Pseudomonas syringae, a plant extracellular pathogen, injects HopW1 effector into host cells to disrupt the actin cytoskeleton and reduce vesicle movement in order to elude defense responses. In some Arabidopsis accessions, however, HopW1 is recognized and causes resistance via an actin-independent mechanism. HopW1 targets isoform 7 of vegetative actin (ACT7) that is regulated by phytohormones and environmental factors. We hypothesize that dynamic changes of ACT7 filaments are involved in plant immunity. PMID:25551177

  12. Point of care nucleic acid detection of viable pathogenic bacteria with isothermal RNA amplification based paper biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Hongxing; Xing, Da; Zhou, Xiaoming

    2014-09-01

    Food-borne pathogens such as Listeria monocytogenes have been recognized as a major cause of human infections worldwide, leading to substantial health problems. Food-borne pathogen identification needs to be simpler, cheaper and more reliable than the current traditional methods. Here, we have constructed a low-cost paper biosensor for the detection of viable pathogenic bacteria with the naked eye. In this study, an effective isothermal amplification method was used to amplify the hlyA mRNA gene, a specific RNA marker in Listeria monocytogenes. The amplification products were applied to the paper biosensor to perform a visual test, in which endpoint detection was performed using sandwich hybridization assays. When the RNA products migrated along the paper biosensor by capillary action, the gold nanoparticles accumulated at the designated Test line and Control line. Under optimized experimental conditions, as little as 0.5 pg/μL genomic RNA from Listeria monocytogenes could be detected. The whole assay process, including RNA extraction, amplification, and visualization, can be completed within several hours. The developed method is suitable for point-of-care applications to detect food-borne pathogens, as it can effectively overcome the false-positive results caused by amplifying nonviable Listeria monocytogenes.

  13. Biological preparation of highly effective immunomagnetic beads for the separation, concentration, and detection of pathogenic bacteria in milk.

    PubMed

    Lim, Min-Cheol; Lee, Gwan-Hyung; Huynh, Duyen Thi Ngoc; Hong, Chae-Eun; Park, Soo-Yeon; Jung, Jong-Yun; Park, Cheon-Seok; Ko, Sungho; Kim, Young-Rok

    2016-09-01

    We introduce a system for the efficient separation and concentration of pathogenic bacteria using biologically prepared immunomagnetic beads. Amylose magnetic beads (AMBs) were synthesized by an enzymatic reaction of amylosucrase from Deinococcus geothermalis (DGAS). The simple and rapid conjugation of AMBs and antibodies was achieved by the MBP-SPG fusion protein. MBP (maltose binding protein) binds to the surface of an AMB owing to its intrinsic affinity to the di-glucose in the AMB. SPG (streptococcal protein G) fused to the MBP has specific affinity to the Fc region of the antibody. Anti-Escherichia coli O157 antibodies were conjugated to the AMBs through a MBP-SPG linker without any physical and chemical treatments. The efficiency of separation and concentration of the target E. coli O157:H7 by the functionalized AMBs was revealed by plating counting, conventional polymerase chain reaction (PCR), and real-time RCR analysis. The immuno-AMBs effectively separated and concentrated the target bacteria from a commercial milk sample spiked with known number of bacteria, which was then analyzed by PCR to a detection limit of 10CFU/mL. On the other hand, no PCR product was produced when milk was introduced directly to a PCR reaction. These results show that MBP-SPG is an effective linker and the resulting immuno-AMBs are capable of separating and concentrating the target bacteria from a food matrix. PMID:27315334

  14. Rapid concentration of bacteria using submicron magnetic anion exchangers for improving PCR-based multiplex pathogen detection.

    PubMed

    Yang, Kun; Jenkins, Daniel M; Su, Wei Wen

    2011-07-01

    Rapid concentration of bacterial targets from dilute solutions to improve subsequent PCR detection is investigated in this study. Submicron (average size 500nm) superparamagnetic anion-exchangers (SiMAG-DEAE) were used successfully to concentrate target bacteria from very dilute solutions. A mass-balance model predicted that for Escherichia coli, the extent of cell concentrating increases almost linearly with increasing sample/SiMAG volume ratio up to about 2000, accompanied by only a slight decrease in the capture efficiency (<10%). Our experimental data generally support this analysis in that the SiMAG beads concentrated bacterial targets by two to three orders of magnitude using a sample/bead volume ratio of about 1000, and lowered the PCR detection limit to a level of 10(2)CFU/mL, from 10(4) to 10(5)CFU/mL without concentrating. Several target bacteria can be concentrated concurrently and detected via multiplex PCR, as illustrated using E. coli and Agrobacterium tumefaciens as model bacteria. Finally, concentration and detection of bacteria in fresh produce samples were demonstrated. The integration of submicron magnetic ion exchangers and PCR detection provides an appealing alternative to immunomagnetic separation/PCR in improving pathogen detection.

  15. Phylogenetic distribution of symbiotic bacteria from Panamanian amphibians that inhibit growth of the lethal fungal pathogen Batrachochytrium dendrobatidis.

    PubMed

    Becker, Matthew H; Walke, Jenifer B; Murrill, Lindsey; Woodhams, Douglas C; Reinert, Laura K; Rollins-Smith, Louise A; Burzynski, Elizabeth A; Umile, Thomas P; Minbiole, Kevin P C; Belden, Lisa K

    2015-04-01

    The introduction of next-generation sequencing has allowed for greater understanding of community composition of symbiotic microbial communities. However, determining the function of individual members of these microbial communities still largely relies on culture-based methods. Here, we present results on the phylogenetic distribution of a defensive functional trait of cultured symbiotic bacteria associated with amphibians. Amphibians are host to a diverse community of cutaneous bacteria and some of these bacteria protect their host from the lethal fungal pathogen Batrachochytrium dendrobatidis (Bd) by secreting antifungal metabolites. We cultured over 450 bacterial isolates from the skins of Panamanian amphibian species and tested their interactions with Bd using an in vitro challenge assay. For a subset of isolates, we also completed coculture experiments and found that culturing isolates with Bd had no effect on inhibitory properties of the bacteria, but it significantly decreased metabolite secretion. In challenge assays, approximately 75% of the bacterial isolates inhibited Bd to some extent and these inhibitory isolates were widely distributed among all bacterial phyla. Although there was no clear phylogenetic signal of inhibition, three genera, Stenotrophomonas, Aeromonas and Pseudomonas, had a high proportion of inhibitory isolates (100%, 77% and 73%, respectively). Overall, our results demonstrate that antifungal properties are phylogenetically widespread in symbiotic microbial communities of Panamanian amphibians and that some functional redundancy for fungal inhibition occurs in these communities. We hope that these findings contribute to the discovery and development of probiotics for amphibians that can mitigate the threat of chytridiomycosis.

  16. Genetic Diversity and Pathogenic Variation of Common Blight Bacteria (Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans) Suggests Pathogen Coevolution with the Common Bean.

    PubMed

    Mkandawire, Alexander B C; Mabagala, Robert B; Guzmán, Pablo; Gepts, Paul; Gilbertson, Robert L

    2004-06-01

    ABSTRACT Common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans, is one of the most important diseases of common bean (Phaseolus vulgaris) in East Africa and other bean-growing regions. Xanthomonad-like bacteria associated with CBB in Malawi and Tanzania, East Africa, and in Wisconsin, U.S., were characterized based on brown pigment production, pathogenicity on common bean, detection with an X. campestris pv. phaseoli- or X. campestris pv. phaseoli var. fuscans-specific PCR primer pair, and repetitive element polymerase chain reaction (rep-PCR) and restriction fragment length polymorphism (RFLP) analyses. The common bean gene pool (Andean or Middle American) from which each strain was isolated also was determined. In Malawi, X. campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans were isolated predominantly from Andean or Middle American beans, respectively. In Tanzania, X. campestris pv. phaseoli var. fuscans was most commonly isolated, irrespective of gene pool; whereas, in Wisconsin, only X. campestris pv. phaseoli was isolated from Andean red kidney beans. Three rep-PCR fingerprints were obtained for X. campestris pv. phaseoli strains; two were unique to East African strains, whereas the other was associated with strains collected from all other (mostly New World) locations. RFLP analyses with repetitive DNA probes revealed the same genetic diversity among X. campestris pv. phaseoli strains as did rep-PCR. These probes hybridized with only one or two fragments in the East African strains, but with multiple fragments in the other X. campestris pv. phaseoli strains. East African X. campestris pv. phaseoli strains were highly pathogenic on Andean beans, but were significantly less pathogenic on Middle American beans. In contrast, X. campestris pv. phaseoli strains from New World locations were highly pathogenic on beans of both gene pools. Together, these results indicate the

  17. Genetic Diversity and Pathogenic Variation of Common Blight Bacteria (Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans) Suggests Pathogen Coevolution with the Common Bean.

    PubMed

    Mkandawire, Alexander B C; Mabagala, Robert B; Guzmán, Pablo; Gepts, Paul; Gilbertson, Robert L

    2004-06-01

    ABSTRACT Common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans, is one of the most important diseases of common bean (Phaseolus vulgaris) in East Africa and other bean-growing regions. Xanthomonad-like bacteria associated with CBB in Malawi and Tanzania, East Africa, and in Wisconsin, U.S., were characterized based on brown pigment production, pathogenicity on common bean, detection with an X. campestris pv. phaseoli- or X. campestris pv. phaseoli var. fuscans-specific PCR primer pair, and repetitive element polymerase chain reaction (rep-PCR) and restriction fragment length polymorphism (RFLP) analyses. The common bean gene pool (Andean or Middle American) from which each strain was isolated also was determined. In Malawi, X. campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans were isolated predominantly from Andean or Middle American beans, respectively. In Tanzania, X. campestris pv. phaseoli var. fuscans was most commonly isolated, irrespective of gene pool; whereas, in Wisconsin, only X. campestris pv. phaseoli was isolated from Andean red kidney beans. Three rep-PCR fingerprints were obtained for X. campestris pv. phaseoli strains; two were unique to East African strains, whereas the other was associated with strains collected from all other (mostly New World) locations. RFLP analyses with repetitive DNA probes revealed the same genetic diversity among X. campestris pv. phaseoli strains as did rep-PCR. These probes hybridized with only one or two fragments in the East African strains, but with multiple fragments in the other X. campestris pv. phaseoli strains. East African X. campestris pv. phaseoli strains were highly pathogenic on Andean beans, but were significantly less pathogenic on Middle American beans. In contrast, X. campestris pv. phaseoli strains from New World locations were highly pathogenic on beans of both gene pools. Together, these results indicate the

  18. The inhibitory effect of natural bioactives on the growth of pathogenic bacteria

    PubMed Central

    Kim, Ji-Sun

    2007-01-01

    The objective of this study was to evaluate the inhibitory activity of natural products, against growth of Escherichia coli (ATCC 25922) and Salmonella typhimurium (KCCM 11862). Chitosan, epigallocatechin gallate (EGCG), and garlic were used as natural bioactives for antibacterial activity. The testing method was carried out according to the disk diffusion method. All of chitosan, EGCG, and garlic showed inhibitory effect against the growth of E. coli and Salmonella typhi. To evaluate the antibacterial activity of natural products during storage, chicken skins were inoculated with 106 of E. coli or Salmonella typhi. The inoculated chicken skins, treated with 0.5, 1, or 2% natural bioactives, were stored during 8 day at 4℃. The numbers of microorganisms were measured at 8 day. Both chitosan and EGCG showed significant decrease in the number of E. coli and Salmonella typhi in dose dependent manner (P < 0.05). These results suggest that natural bioactives such as chitosan, EGCG may be possible to be used as antimicrobial agents for the improvement of food safety. PMID:20368950

  19. In vitro activity of glucosinolates and their degradation products against brassica-pathogenic bacteria and fungi.

    PubMed

    Sotelo, T; Lema, M; Soengas, P; Cartea, M E; Velasco, P

    2015-01-01

    Glucosinolates (GSLs) are secondary metabolites found in Brassica vegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about their in vitro biocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enriched Brassica crops on suppressing in vitro growth of two bacterial (Xanthomonas campestris pv. campestris and Pseudomonas syringae pv. maculicola) and two fungal (Alternaria brassicae and Sclerotinia scletoriorum) Brassica pathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of different Brassica species, have potential to inhibit pathogen growth and offer new opportunities to study the use of Brassica crops in biofumigation for the control of multiple diseases.

  20. Exposure to natural pathogens reveals costly aphid response to fungi but not bacteria

    PubMed Central

    Barribeau, Seth M; Parker, Benjamin J; Gerardo, Nicole M

    2014-01-01

    Immune responses are costly, causing trade-offs between defense and other host life history traits. Aphids present a special system to explore the costs associated with immune activation since they are missing several humoral and cellular mechanisms thought important for microbial resistance, and it is unknown whether they have alternative, novel immune responses to deal with microbial threat. Here we expose pea aphids to an array of heat-killed natural pathogens, which should stimulate immune responses without pathogen virulence, and measure changes in life-history traits. We find significant reduction in lifetime fecundity upon exposure to two fungal pathogens, but not to two bacterial pathogens. This finding complements recent genomic and immunological studies indicating that pea aphids are missing mechanisms important for bacterial resistance, which may have important implications for how aphids interact with their beneficial bacterial symbionts. In general, recent exploration of the immune systems of non-model invertebrates has called into question the generality of our current picture of insect immunity. Our data highlight that taking an ecological approach and measuring life-history traits to a broad array of pathogens provides valuable information that can complement traditional approaches. PMID:24634732

  1. In Vitro Activity of Glucosinolates and Their Degradation Products against Brassica-Pathogenic Bacteria and Fungi

    PubMed Central

    Sotelo, T.; Lema, M.; Soengas, P.; Cartea, M. E.

    2014-01-01

    Glucosinolates (GSLs) are secondary metabolites found in Brassica vegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about their in vitro biocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enriched Brassica crops on suppressing in vitro growth of two bacterial (Xanthomonas campestris pv. campestris and Pseudomonas syringae pv. maculicola) and two fungal (Alternaria brassicae and Sclerotinia scletoriorum) Brassica pathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of different Brassica species, have potential to inhibit pathogen growth and offer new opportunities to study the use of Brassica crops in biofumigation for the control of multiple diseases. PMID:25362058

  2. Effect of hand wash agents on controlling the transmission of pathogenic bacteria from hands to food.

    PubMed

    Fischler, George E; Fuls, Janice L; Dail, Elizabeth W; Duran, Melani H; Rodgers, Nancy D; Waggoner, Andrea L

    2007-12-01

    The goals of this study were to evaluate the effectiveness of two hand wash regimens in reducing transient bacteria on the skin following a single hand wash and the subsequent transfer of the bacteria to a ready-to-eat food item, freshly cut cantaloupe melon. The number of bacteria recovered from hands and the quantity transferred to the melon were significantly less following the use of an antibacterial soap compared with plain soap. The antimicrobial soap achieved > 3-log reductions versus Escherichia coli and 3.31- and 2.83-log reductions versus Shigella flexneri. The plain soap failed to achieve a 2-log reduction against either organism. The bacteria recovered from the melon handled by hands treated with antimicrobial hand soap averaged 2 log. Melon handled following hand washing with plain soap had > 3 log bacteria in the experiments. Based on previously published feeding studies, an infection rate in the range of approximately 15 to 25% would be expected after ingesting melon containing 2 log CFU compared with ingesting greater than the 3 log transferred from hands washed with plain soap, which would result in a higher infection attack rate of 50 to 80%. The data thus demonstrate there is a greater potential to reduce the transmission and acquisition of disease through the use of an antimicrobial hand wash than through the use of plain soap.

  3. The eye fly Siphunculina funicola (Diptera: Chloropidae) as a carrier of pathogenic bacteria in Thailand.

    PubMed

    Chansang, Uruyakorn; Mulla, Mir S; Chantaroj, Siriporn; Sawanpanyalert, Pathom

    2010-01-01

    The oriental eye fly Siphunculina funicola (1.0-1.6 mm) is extremely annoying to humans and domestic animals, feeding on mucous membranes, secretions, wounds, eyes, and other moist surfaces of the host body. In many rural areas of Thailand heavy populations of this fly prevail where they aggregate on a variety of hanging substrates, such as strings, nest trailings, electrical lines, decorations, ropes, cob webs, clothes hangers, automobile radio antennae and other items in open shade close to their hosts. Both males and females feed voraciously on wounds and moist skin. With this type of persistent feeding, the eye flies are suspected to carry and transfer germs to their hosts. In the present study, bacteria were isolated from S. funicola captured from wounds, host seeking flies and from their resting sites. Some enriched and bacterial culture media were more suitable for isolation than others. A diverse group of bacteria (64 species), both gram-posi-tive and gram-negative, most in risk category 2, were identified. Bacterial colony counts from Trypic soy broth ranged from 10 to > 3.0 x 10(3) cfu/ml. The most common bacteria isolated were Acinetobacter, Aeromonas, Bacillus, Corynebacterium, Enterobacter, Enterococcus, Escherichia, Kocuria, Pantoea, Pseudomonas, Staphylococcus and others. These bacteria may cause disease conditions in humans and animals. This is the first time bacteria from S. funicola have been reported.

  4. Screening and modes of action of antagonistic bacteria to control the fungal pathogen Phaeomoniella chlamydospora involved in grapevine trunk diseases.

    PubMed

    Haidar, Rana; Roudet, Jean; Bonnard, Olivier; Dufour, Marie Cécile; Corio-Costet, Marie France; Fert, Mathieu; Gautier, Thomas; Deschamps, Alain; Fermaud, Marc

    2016-11-01

    The antagonistic activity of 46 bacterial strains isolated from Bordeaux vineyards were evaluated against Phaeomoniella chlamydospora, a major grapevine pathogen involved in Esca. The reduction of the necrosis length of stem cuttings ranged between 31.4% and 38.7% for the 8 most efficient strains. Two in planta trials allowed the selection of the two best strains, Bacillus pumilus (S32) and Paenibacillus sp. (S19). Their efficacy was not dependent on application method; co-inoculation, prevention in the wood and soil inoculation were tested. The involvement of antibiosis by the secretion of diffusible and/or volatile compounds in the antagonistic capacity of these two strains was assessed in vitro. Volatile compounds secreted by B. pumilus (S32) and Paenibacillus sp. (S19) were identified by gas chromatography/mass spectroscopy (GC/MS). The volatile compounds 1-octen-3-ol and 2,5-dimethyl pyrazine were obtained commercially and tested, and they showed strong antifungal activity against P. chlamydospora, which suggested that these compounds may play an important role in the bacterial antagonistic activity in planta. Furthermore, the expression of 10 major grapevine defense genes was quantified by real-time polymerase chain reaction, which demonstrated that the two strains significantly affected the grapevine transcripts four days after their application on the plants. High expression levels of different genes associated with P. chlamydospora infection in B. pumilus pre-treated plants suggests that this strain induces systemic resistance in grapevine. For the first time, we demonstrated the ability of two bacterial strains, B. pumilus and Paenibacillus sp., isolated from grapevine wood, to control P. chlamydospora via direct and/or indirect mechanisms.

  5. Screening and modes of action of antagonistic bacteria to control the fungal pathogen Phaeomoniella chlamydospora involved in grapevine trunk diseases.

    PubMed

    Haidar, Rana; Roudet, Jean; Bonnard, Olivier; Dufour, Marie Cécile; Corio-Costet, Marie France; Fert, Mathieu; Gautier, Thomas; Deschamps, Alain; Fermaud, Marc

    2016-11-01

    The antagonistic activity of 46 bacterial strains isolated from Bordeaux vineyards were evaluated against Phaeomoniella chlamydospora, a major grapevine pathogen involved in Esca. The reduction of the necrosis length of stem cuttings ranged between 31.4% and 38.7% for the 8 most efficient strains. Two in planta trials allowed the selection of the two best strains, Bacillus pumilus (S32) and Paenibacillus sp. (S19). Their efficacy was not dependent on application method; co-inoculation, prevention in the wood and soil inoculation were tested. The involvement of antibiosis by the secretion of diffusible and/or volatile compounds in the antagonistic capacity of these two strains was assessed in vitro. Volatile compounds secreted by B. pumilus (S32) and Paenibacillus sp. (S19) were identified by gas chromatography/mass spectroscopy (GC/MS). The volatile compounds 1-octen-3-ol and 2,5-dimethyl pyrazine were obtained commercially and tested, and they showed strong antifungal activity against P. chlamydospora, which suggested that these compounds may play an important role in the bacterial antagonistic activity in planta. Furthermore, the expression of 10 major grapevine defense genes was quantified by real-time polymerase chain reaction, which demonstrated that the two strains significantly affected the grapevine transcripts four days after their application on the plants. High expression levels of different genes associated with P. chlamydospora infection in B. pumilus pre-treated plants suggests that this strain induces systemic resistance in grapevine. For the first time, we demonstrated the ability of two bacterial strains, B. pumilus and Paenibacillus sp., isolated from grapevine wood, to control P. chlamydospora via direct and/or indirect mechanisms. PMID:27664735

  6. Effects of X-ray treatments on pathogenic bacteria, inherent microflora, color, and firmness on whole cantaloupe.

    PubMed

    Mahmoud, Barakat S M

    2012-06-01

    Inactivation of inoculated Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica and Shigella flexneri on whole cantaloupes using X-ray at different doses (0.1, 0.5, 1.0, 1.5, and 2.0 kGy) was studied. The effect of X-ray on quality parameters (color and texture) of untreated and treated whole cantaloupes was instrumentally determined. The effect of X-ray on microflora counts (mesophilic counts, psychrotrophic counts and yeast and mold counts) of untreated and treated whole cantaloupes was also determined during storage at 22°C for 20 days. A mixture of three strains of each tested organism was spot inoculated (100 μl), separately, onto the surface (5 cm(2)) of cantaloupe rinds (approximately 8-9 log CFU ml(-1)) separately, air dried (60 min), and then treated with X-ray at 22°C and 55% relative humidity. Surviving bacterial populations on cantaloupe surfaces were evaluated using a nonselective medium (tryptic soy agar) with a selective medium overlay for each bacterium; E. coli O157:H7 (CT-SMAC agar), L. monocytogenes (MOA), and S. enterica and S. flexneri (XLD). More than a 5 log CFU reduction was achieved after treatment with 2.0 kGy X-ray, for all tested pathogens. No significant effect of X-ray treatment on cantaloupe color or firmness was detected. Furthermore, treatment with X-ray significantly reduced the initial inherent microflora on whole cantaloupes and inherent levels were significantly (p<0.05) lower than the control sample throughout storage for 20 days.

  7. Recent Advancements in Nanobioassays and Nanobiosensors for Foodborne Pathogenic Bacteria Detection.

    PubMed

    Chen, Jing; Park, Bosoon

    2016-06-01

    Bacterial pathogens are one of the leading causes of food safety incidents and product recalls worldwide. Timely detection and identification of microbial contamination in agricultural and food products is crucial for disease prevention and outbreak investigation. In efforts to improve and/or replace time-consuming and laborious "gold standards" for pathogen detection, numerous alternative rapid methods have been proposed in the past 15 years, with a trend toward incorporating nanotechnology and nanomaterials in food pathogen detection. This article is a review of the use of nanotechnology in various detection and sample preparation techniques and advancements in nanotechnology applications in food matrices. Some practical considerations in nanobioassay design are discussed, and the gaps between research status quo and market demands are identified.

  8. Recent Advancements in Nanobioassays and Nanobiosensors for Foodborne Pathogenic Bacteria Detection.

    PubMed

    Chen, Jing; Park, Bosoon

    2016-06-01

    Bacterial pathogens are one of the leading causes of food safety incidents and product recalls worldwide. Timely detection and identification of microbial contamination in agricultural and food products is crucial for disease prevention and outbreak investigation. In efforts to improve and/or replace time-consuming and laborious "gold standards" for pathogen detection, numerous alternative rapid methods have been proposed in the past 15 years, with a trend toward incorporating nanotechnology and nanomaterials in food pathogen detection. This article is a review of the use of nanotechnology in various detection and sample preparation techniques and advancements in nanotechnology applications in food matrices. Some practical considerations in nanobioassay design are discussed, and the gaps between research status quo and market demands are identified. PMID:27296612

  9. Screening of antibacterial activity of lactic acid bacteria against different pathogens found in vacuum-packaged meat products.

    PubMed

    Awaisheh, Saddam S; Ibrahim, Salam A

    2009-11-01

    The objective of this work was to screen the antibacterial activity of lactic acid bacteria (LAB) isolated from different sources against different pathogens found in ready-to-eat vacuum-packaged meat products (RTE-VPMP). LAB were isolated from human, RTE-VPMP, fermented vegetables, and dairy samples. These isolates were assessed for their antibacterial activity against Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus using spot on lawn technique. Six LAB isolates-three from a human source, two from a RTE-VPMP source, and one from a fermented vegetable source-were found to be effective against all pathogenic strains. Antibacterial activities of cell-free neutral supernatant broths of these isolates were assessed against the different pathogenic strains to confirm bacteriocin production. All six isolates were effective against all pathogenic strains. LAB isolates from the human source had the highest antibacterial activity and were significantly more effective than other LAB isolates, with the inhibition zone ranging from 14 to 22 mm. Inhibition zones of RTE-VPMP LAB isolates were lower than those of human origin (inhibition zone range, 11-17 mm). The lowest activities were for the fermented vegetable isolate, for which inhibition zones ranged from 11 to 15 mm. The three isolates of human origin were identified as L. acidophilus, L. casei, and L. reuteri; the two isolates from RTE-VPMP source were both L. sake; and the one isolate of fermented vegetable origin was L. plantarum. Our results showed that nonmeat product-sourced LAB were effective against several foodborne pathogens, which suggests that they could be used as natural biopreservatives in many RTE-VPMP produced in Jordan.

  10. Alendronate augments interleukin-1{beta} release from macrophages infected with periodontal pathogenic bacteria through activation of caspase-1

    SciTech Connect

    Deng Xue; Tamai, Riyoko; Endo, Yasuo; Kiyoura, Yusuke

    2009-02-15

    Nitrogen-containing bisphosphonates (NBPs) are anti-bone-resorptive drugs with inflammatory side effects that include osteomyelitis and osteonecrosis of the jaw. Oral bacteria have been considered to be a trigger for these NBP-associated jaw bone diseases. The present study examined the effects of alendronate (a typical NBP) and clodronate (a non-NBP) on the production of proinflammatory cytokines by macrophages infected with Porphyromonas gingivalis and Tannerella forsythia, which are important pathogens of periodontal diseases. Pretreatment with alendronate augmented IL-1{beta}, but not TNF{alpha}, production by macrophages infected with P. gingivalis or T. forsythia. This augmentation of IL-1{beta} production was inhibited by clodronate. Furthermore, caspase-1, a promoter of IL-1{beta} production, was activated by treatment with alendronate, and caspase-1 inhibitor reduced the production of IL-1{beta} induced by alendronate and P. gingivalis. These results suggest that NBPs augment periodontal pathogenic bacteria-induced IL-1{beta} release via caspase-1 activation, and this phenomenon may contribute to the development of NBP-associated inflammatory side effects including jaw osteomyelitis. Co-treatment with clodronate may prevent and/or reduce these inflammatory effects induced by NBPs.

  11. [Study on the histopathology of cats inoculated with H5N1 subtype high pathogenic avian influenza virus originated from tigers].

    PubMed

    Chang, Shuang; Ding, Zhuang; Yang, Song-Tao; Gao, Yu-Wei; Zou, Xiao-Huan; Wang, Tie-Cheng; Xia, Xian-Zhu

    2007-11-01

    In this study, the HPAIV A/Tiger/Harbin/01/2002 (H5N1) used was originated from tigers and propagated in SPF embryonated hen eggs. TCID5, of the virus was 10(-7.36)/0. 05mL on MDCK cell. The cats were inoculated through bronchus route and then, the cats of dead and control were collected for histopathological and immunohistochemistry examination. Meanwhile, the emulsion supernatant fluid of organs and the pharyngeal swab samples of the dead cats were collected for RT-PCR, survived cats and the control cats were tested for the presence of HI antibody by standard method. The results indicated that the damage of lungs from the dead cats were most obvious, the wide range of red consolidation focus emerged on the lobus pulmonis, the fused focus of infection caused injury of lungs. Histology under the microscope revealed diffuse alveolar damage, confluence phlegmasia pathology, infiltration of lymphomonocytes, sackful of infiltration of macrophages and manipulus protein-like effusion in the alveolar. By immunohistochemistry, the positively stained virus particles were found on the epithelial cells of bronchus and alveolus, and also in the endochylema of lymphomonocytes. The specific electophoretic band of 464bp amplified by RT-PCR from samples of pharyngeal swabs, lungs, kidneys, hearts and brains was as same as the theory value. HI antibody titers of the survived cat were 1:32.

  12. Polymerase chain reaction-based serotyping of pathogenic bacteria in food.

    PubMed

    Salazar, Joelle K; Wang, Yun; Yu, Shuijing; Wang, Hui; Zhang, Wei

    2015-03-01

    Serotyping analysis of bacterial pathogens in food products is important for foodborne disease surveillance and outbreak investigations. Traditional immunological techniques are labor-intensive and time-consuming, whereas polymerase chain r eaction (PCR)-based techniques are more robust, consistent and rapid. PCR-based methods also provide easier standardization and better reproducibility. Here, we summarize some recent developments and applications of PCR-based serotyping for common foodborne pathogens, and provide a list of available bioinformatics tools for developing PCR-based serotyping assays.

  13. Survival of pathogenic bacteria under nutrient starvation conditions. [aboard orbiting space stations

    NASA Technical Reports Server (NTRS)

    Boyle, Michael; Ford, Tim; Mitchell, Ralph; Maki, James

    1990-01-01

    The survival of opportunistic pathogenic microorganisms in water, under nutrient-limiting conditions, has been investigated in order to ascertain whether human pathogens can survive within a water-distribution system of the kind proposed for the NASA Space Station. Cultures of a strain of pseudomonas aeruginosa and two strains of staphylococcus aureus were incubated at 10, 25, or 37 C, and samples at 1 day, 1 week, 1 month, and six weeks. While neither of the staphylococcus strains tested were detected after 1 week of starvation, the pseudomonas strain can survive in deionized water at all three temperatures.

  14. Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

    NASA Technical Reports Server (NTRS)

    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.

  15. Recent Advancements in Nanobioassays and Nanobiosensors for Foodborne Pathogenic Bacteria Detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial pathogens are one of the leading causes of food safety incidents and product recalls worldwide. Timely detection and identification of microbial contamination in agricultural and food products is crucial for disease prevention and outbreak investigation. Current gold standards are specific...

  16. Potential of predatory bacteria as biocontrol agents for foodborne and plant pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne pathogens such as Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, Shigella are responsible for frequent occurrences of illnesses and mortality in humans and produce losses. Pre-harvest yield losses and post-harvest decay on minimally processed produce (fruits, vegetables...

  17. Diarrhea-associated pathogens, lactobacilli and cellulolytic bacteria in equine feces: responses to antibiotic challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibiotics are important to equine medicine, but antibiotic-associated diarrhea (AAD) can lead to poor performance and even mortality. AAD is attributed to disruption of the hindgut microbiota, which permits proliferation of pathogenic microbes. The goal of this study was to evaluate the effects o...

  18. New findings from an old pathogen: intraerythrocytic bacteria (family Anaplasmatacea) in red-backed salamanders Plethodon cinereus.

    PubMed

    Davis, Andrew K; DeVore, Jayna L; Milanovich, Joseph R; Cecala, Kristen; Maerz, John C; Yabsley, Michael J

    2009-06-01

    During a recent study of red-backed salamanders (Plethodon cinereus), we discovered an intraerythrocytic organism typified by violet-staining, intracellular inclusions, consistent with descriptions of Cytamoeba or Aegyptianella (bacteria). Here we characterize its taxonomic status using molecular techniques and ask basic questions about its nature. Blood smears from 102 salamanders were examined from Pennsylvania, New York, and Virginia to determine prevalence, and whole blood from several infected animals was tested using a PCR which targets the 16S rRNA gene of bacteria. Phylogenetic analysis of partial 16S rRNA gene sequence (1201 bp) indicated this organism was in the order Rickettsiales and is likely a member of the family Anaplasmatacea. The organism differed from currently described taxa and was clearly differentiated from Aegyptianella pullorum of birds and "Candidatus Hemobacterium ranarum" (formally A. ranarum) of frogs. Of all salamanders, 17 (16.7%) were infected and these were significantly larger (snout-vent length) and had higher body condition scores than uninfected ones, and males were more likely to be infected than females. Erythrocytes affected by the pathogen were 5% larger than unaffected ones, but otherwise similar in morphology. Infected animals tended to have a greater number of circulating white blood cells, based on estimates from smears, indicating a nonspecific response to the pathogen by the innate immune system. Given its phylogenetic position, this pathogen is likely transmitted by an arthropod vector, and the male-biased prevalence strongly implicates trombiculid mites, which also live in leaf litter and affect male salamanders more so than females.

  19. Antibacterial activity of guava (Psidium guajava L.) and Neem (Azadirachta indica A. Juss.) extracts against foodborne pathogens and spoilage bacteria.

    PubMed

    Mahfuzul Hoque, M D; Bari, M L; Inatsu, Y; Juneja, Vijay K; Kawamoto, S

    2007-01-01

    The antibacterial activity of guava (Psidium guajava) and neem (Azadirachta indica) extracts against 21 strains of foodborne pathogens were determined--Listeria monocytogenes (five strains), Staphylococcus aureus (four strains), Escherichia coli O157:H7 (six strains), Salmonella Enteritidis (four strains), Vibrio parahaemolyticus, and Bacillus cereus, and five food spoilage bacteria: Pseudomonas aeroginosa, P. putida, Alcaligenes faecalis, and Aeromonas hydrophila (two strains). Guava and neem extracts showed higher antimicrobial activity against Gram-positive bacteria compared to Gram-negative bacteria except for V. parahaemolyticus, P. aeroginosa, and A. hydrophila. None of the extracts showed antimicrobial activity against E. coli O157:H7 and Salmonella Enteritidis. The minimum inhibitory concentration (MIC) of ethanol extracts of guava showed the highest inhibition for L. monocytogenes JCM 7676 (0.1 mg/mL), S. aureus JCM 2151 (0.1 mg/mL), S. aureus JCM 2179 (0.1 mg/mL), and V. parahaemolyticus IFO 12711 (0.1 mg/mL) and the lowest inhibition for Alcaligenes faecalis IFO 12669, Aeromonas hydrophila NFRI 8282 (4.0 mg/mL), and A. hydrophila NFRI 8283 (4.0 mg/mL). The MIC of chloroform extracts of neem showed similar inhibition for L. monocytogenes ATCC 43256 (4.0 mg/mL) and L. monocytogenes ATCC 49594 (5.0 mg/mL). However, ethanol extracts of neem showed higher inhibition for S. aureus JCM 2151 (4.5 mg/mL) and S. aureus IFO 13276 (4.5 mg/mL) and the lower inhibition for other microorganisms (6.5 mg/mL). No significant effects of temperature and pH were found on guava and neem extracts against cocktails of L. monocytogenes and S. aureus. The results of the present study suggest that guava and neem extracts possess compounds containing antibacterial properties that can potentially be useful to control foodborne pathogens and spoilage organisms.

  20. Antibacterial activities of metabolites from Platanus occidenatalis (American sycamore) against fish pathogenic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentall...

  1. Antibacterial activities of metabolites from Platanus occidentalis (American sycamore) against fish pathogenic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentall...

  2. Pulsed-light inactivation of pathogenic and spoilage bacteria on cheese surface.

    PubMed

    Proulx, J; Hsu, L C; Miller, B M; Sullivan, G; Paradis, K; Moraru, C I

    2015-09-01

    Cheese products are susceptible to postprocessing cross-contamination by bacterial surface contamination during slicing, handling, or packaging, which can lead to food safety issues and significant losses due to spoilage. This study examined the effectiveness of pulsed-light (PL) treatment on the inactivation of the spoilage microorganism Pseudomonas fluorescens, the nonenterohemorrhagic Escherichia coli ATCC 25922 (nonpathogenic surrogate of Escherichia coli O157:H7), and Listeria innocua (nonpathogenic surrogate of Listeria monocytogenes) on cheese surface. The effects of inoculum level and cheese surface topography and the presence of clear polyethylene packaging were evaluated in a full factorial experimental design. The challenge microorganisms were grown to early stationary phase and subsequently diluted to reach initial inoculum levels of either 5 or 7 log cfu/slice. White Cheddar and process cheeses were cut into 2.5×5 cm slices, which were spot-inoculated with 100 µL of bacterial suspension. Inoculated cheese samples were exposed to PL doses of 1.02 to 12.29 J/cm(2). Recovered survivors were enumerated by standard plate counting or the most probable number technique, as appropriate. The PL treatments were performed in triplicate and data were analyzed using a general linear model. Listeria innocua was the least sensitive to PL treatment, with a maximum inactivation level of 3.37±0.2 log, followed by P. fluorescens, with a maximum inactivation of 3.74±0.8 log. Escherichia coli was the most sensitive to PL, with a maximum reduction of 5.41±0.1 log. All PL inactivation curves were nonlinear, and inactivation reached a plateau after 3 pulses (3.07 J/cm(2)). The PL treatments through UV-transparent packaging and without packaging consistently resulted in similar inactivation levels. This study demonstrates that PL has strong potential for decontamination of the cheese surface. PMID:26162787

  3. Pulsed-light inactivation of pathogenic and spoilage bacteria on cheese surface.

    PubMed

    Proulx, J; Hsu, L C; Miller, B M; Sullivan, G; Paradis, K; Moraru, C I

    2015-09-01

    Cheese products are susceptible to postprocessing cross-contamination by bacterial surface contamination during slicing, handling, or packaging, which can lead to food safety issues and significant losses due to spoilage. This study examined the effectiveness of pulsed-light (PL) treatment on the inactivation of the spoilage microorganism Pseudomonas fluorescens, the nonenterohemorrhagic Escherichia coli ATCC 25922 (nonpathogenic surrogate of Escherichia coli O157:H7), and Listeria innocua (nonpathogenic surrogate of Listeria monocytogenes) on cheese surface. The effects of inoculum level and cheese surface topography and the presence of clear polyethylene packaging were evaluated in a full factorial experimental design. The challenge microorganisms were grown to early stationary phase and subsequently diluted to reach initial inoculum levels of either 5 or 7 log cfu/slice. White Cheddar and process cheeses were cut into 2.5×5 cm slices, which were spot-inoculated with 100 µL of bacterial suspension. Inoculated cheese samples were exposed to PL doses of 1.02 to 12.29 J/cm(2). Recovered survivors were enumerated by standard plate counting or the most probable number technique, as appropriate. The PL treatments were performed in triplicate and data were analyzed using a general linear model. Listeria innocua was the least sensitive to PL treatment, with a maximum inactivation level of 3.37±0.2 log, followed by P. fluorescens, with a maximum inactivation of 3.74±0.8 log. Escherichia coli was the most sensitive to PL, with a maximum reduction of 5.41±0.1 log. All PL inactivation curves were nonlinear, and inactivation reached a plateau after 3 pulses (3.07 J/cm(2)). The PL treatments through UV-transparent packaging and without packaging consistently resulted in similar inactivation levels. This study demonstrates that PL has strong potential for decontamination of the cheese surface.

  4. Glycan:glycan interactions: High affinity biomolecular interactions that can mediate binding of pathogenic bacteria to host cells

    PubMed Central

    Day, Christopher J.; Tran, Elizabeth N.; Semchenko, Evgeny A.; Tram, Greg; Hartley-Tassell, Lauren E.; Ng, Preston S. K.; King, Rebecca M.; Ulanovsky, Rachel; McAtamney, Sarah; Apicella, Michael A.; Tiralongo, Joe; Morona, Renato; Korolik, Victoria; Jennings, Michael P.

    2015-01-01

    Cells from all domains of life express glycan structures attached to lipids and proteins on their surface, called glycoconjugates. Cell-to-cell contact mediated by glycan:glycan interactions have been considered to be low-affinity interactions that precede high-affinity protein–glycan or protein–protein interactions. In several pathogenic bacteria, truncation of surface glycans, lipooligosaccharide (LOS), or lipopolysaccharide (LPS) have been reported to significantly reduce bacterial adherence to host cells. Here, we show that the saccharide component of LOS/LPS have direct, high-affinity interactions with host glycans. Glycan microarrays reveal that LOS/LPS of four distinct bacterial pathogens bind to numerous host glycan structures. Surface plasmon resonance was used to determine the affinity of these interactions and revealed 66 high-affinity host–glycan:bacterial–glycan pairs with equilibrium dissociation constants (KD) ranging between 100 nM and 50 µM. These glycan:glycan affinity values are similar to those reported for lectins or antibodies with glycans. Cell assays demonstrated that glycan:glycan interaction-mediated bacterial adherence could be competitively inhibited by either host cell or bacterial glycans. This is the first report to our knowledge of high affinity glycan:glycan interactions between bacterial pathogens and the host. The discovery of large numbers of glycan:glycan interactions between a diverse range of structures suggests that these interactions may be important in all biological systems. PMID:26676578

  5. Glycan:glycan interactions: High affinity biomolecular interactions that can mediate binding of pathogenic bacteria to host cells.

    PubMed

    Day, Christopher J; Tran, Elizabeth N; Semchenko, Evgeny A; Tram, Greg; Hartley-Tassell, Lauren E; Ng, Preston S K; King, Rebecca M; Ulanovsky, Rachel; McAtamney, Sarah; Apicella, Michael A; Tiralongo, Joe; Morona, Renato; Korolik, Victoria; Jennings, Michael P

    2015-12-29

    Cells from all domains of life express glycan structures attached to lipids and proteins on their surface, called glycoconjugates. Cell-to-cell contact mediated by glycan:glycan interactions have been considered to be low-affinity interactions that precede high-affinity protein-glycan or protein-protein interactions. In several pathogenic bacteria, truncation of surface glycans, lipooligosaccharide (LOS), or lipopolysaccharide (LPS) have been reported to significantly reduce bacterial adherence to host cells. Here, we show that the saccharide component of LOS/LPS have direct, high-affinity interactions with host glycans. Glycan microarrays reveal that LOS/LPS of four distinct bacterial pathogens bind to numerous host glycan structures. Surface plasmon resonance was used to determine the affinity of these interactions and revealed 66 high-affinity host-glycan:bacterial-glycan pairs with equilibrium dissociation constants (K(D)) ranging between 100 nM and 50 µM. These glycan:glycan affinity values are similar to those reported for lectins or antibodies with glycans. Cell assays demonstrated that glycan:glycan interaction-mediated bacterial adherence could be competitively inhibited by either host cell or bacterial glycans. This is the first report to our knowledge of high affinity glycan:glycan interactions between bacterial pathogens and the host. The discovery of large numbers of glycan:glycan interactions between a diverse range of structures suggests that these interactions may be important in all biological systems. PMID:26676578

  6. Natural sesquiterpene lactones enhance oxacillin and gentamicin effectiveness against pathogenic bacteria without antibacterial effects on beneficial lactobacilli.

    PubMed

    Cartagena, Elena; Alva, Mariana; Montanaro, Susana; Bardón, Alicia

    2015-05-01

    This is a report on the synergistic interactions (SIs) between melampolide-type sesquiterpene lactones 1-8 from Acanthospermum hispidum DC., and oxacillin or gentamicin, against four pathogenic strains of Staphylococcus aureus and Enterococcus faecalis; two of them were multi-resistant strains obtained from chronic infectious processes. Our results showed that all associations of 1-8 with antibiotics (ATBs) are more effective than pure ATBs to control pathogenic strains of S. aureus and E. faecalis. The most relevant SIs were observed when the major lactone of A. hispidum, acanthospermal B [5], was combined with gentamicin (protein synthesis inhibitor) against an ex vivo culture of methicillin-resistant S. aureus SAR 1, displaying a significant MIC reduction in 5 (312.5 to 78.1 µg/mL), and gentamicin (120 µg/mL to 3 µg/mL). Compound 4 improved the antibiotic potency of oxacillin (cell wall synthesis inhibitor) against ampicillin-resistant E. faecalis (60 µg/mL to 1.5 µg/mL). It is important to remark that three beneficial lactobacilli were resistant to 1-8 and their mixtures with gentamicin or oxacillin in effective concentrations against pathogenic bacteria. Synergism between ATBs and phytochemicals is a therapeutically helpful concept to improve ATB efficacy and prevent resistance. The present results show that selective SIs occur between melampolides and gentamicin or oxacillin, and open a new field of research.

  7. Chemical Composition and In Vitro Antibacterial Activity of Mentha spicata Essential Oil against Common Food-Borne Pathogenic Bacteria.

    PubMed

    Shahbazi, Yasser

    2015-01-01

    The aim of the present study was to investigate chemical composition and antibacterial activity of essential oil from the leaf of Mentha spicata plant against common food-borne pathogenic bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli O157:H7). Chemical composition of the essential oil was identified by gas chromatography coupled with mass spectrometer detector (GC-MS). The antibacterial activity of the essential oil was evaluated by broth microdilution method and agar disk diffusion assay. According to the result of GC-MS analysis, 18 components were identified, accounting for 99.89% of the whole essential oil. The main components were carvone (78.76%), limonene (11.50%), β-bourbonene (11.23%), cis-dihydrocarveol (1.43%), trans-caryophyllene (1.04%), menthone (1.01%), menthol (1%), and terpinen-4-ol (0.99). The essential oil exhibited moderate level of antibacterial activity against all test microorganisms. In general, Gram-positive bacteria were more susceptible to M. spicata essential oil than Gram-negative bacteria. L. monocytogenes was the most sensitive of the microorganisms to the antibacterial activity of M. spicata essential oil (inhibition zone = 22 mm and MIC and MBC = 2.5 µL/mL). Based on our results, the essential oil of M. spicata plant collected from Kermanshah province, west of Iran, has a potential to be applied as antibacterial agent.

  8. Chemical Composition and Antibacterial Activity of Essential Oils of Tagetes minuta (Asteraceae) against Selected Plant Pathogenic Bacteria

    PubMed Central

    Wagacha, John M.; Dossaji, Saifuddin F.

    2016-01-01

    The objective of this study was to determine the chemical composition and antibacterial activity of essential oils (EOs) of Tagetes minuta against three phytopathogenic bacteria Pseudomonas savastanoi pv. phaseolicola, Xanthomonas axonopodis pv. phaseoli, and Xanthomonas axonopodis pv. manihotis. The essential oils were extracted using steam distillation method in a modified Clevenger-type apparatus while antibacterial activity of the EOs was evaluated by disc diffusion method. Gas chromatography coupled to mass spectrometry (GC/MS) was used for analysis of the chemical profile of the EOs. Twenty compounds corresponding to 96% of the total essential oils were identified with 70% and 30% of the identified components being monoterpenes and sesquiterpenes, respectively. The essential oils of T. minuta revealed promising antibacterial activities against the test pathogens with Pseudomonas savastanoi pv. phaseolicola being the most susceptible with mean inhibition zone diameters of 41.83 and 44.83 mm after 24 and 48 hours, respectively. The minimum inhibitory concentrations and minimum bactericidal concentrations of the EOs on the test bacteria were in the ranges of 24–48 mg/mL and 95–190 mg/mL, respectively. These findings provide a scientific basis for the use of T. minuta essential oils as a botanical pesticide for management of phytopathogenic bacteria. PMID:27721831

  9. Chemical Composition and In Vitro Antibacterial Activity of Mentha spicata Essential Oil against Common Food-Borne Pathogenic Bacteria

    PubMed Central

    Shahbazi, Yasser