WorldWideScience

Sample records for relevant bacterial pathogens

  1. Investigation of critical inter-related factors affecting the efficacy of pulsed light for inactivating clinically relevant bacterial pathogens.

    Science.gov (United States)

    Farrell, H P; Garvey, M; Cormican, M; Laffey, J G; Rowan, N J

    2010-05-01

    To investigate critical electrical and biological factors governing the efficacy of pulsed light (PL) for the in vitro inactivation of bacteria isolated from the clinical environment. Development of this alternative PL decontamination approach is timely, as the incidence of health care-related infections remains unacceptably high. Predetermined cell numbers of clinically relevant Gram-positive and Gram-negative bacteria were inoculated separately on agar plates and were flashed with pulses of broad-spectrum light under varying operating conditions, and their inactivation measured. Significant differences in inactivation largely occurred depending on the level of the applied lamp discharge energy (range 3.2-20 J per pulse), the amount of pulsing applied (range 0-60 pulses) and the distance between light source and treatment surface (range 8-20 cm) used. Greater decontamination levels were achieved using a combination of higher lamp discharge energies, increased number of pulses and shorter distances between treatment surface and the xenon light source. Levels of microbial sensitivity also varied depending on the population type, size and age of cultures treated. Production of pigment pyocynanin and alginate slime in mucoid strains of Pseudomonas aeruginosa afforded some protection against lethal action of PL; however, this was evident only by using a combination of reduced amount of pulsing at the lower lamp discharge energies tested. A clear pattern was observed where Gram-positive bacterial pathogens were more resistant to cidal effects of PL compared to Gram negatives. While negligible photoreactivation of PL-treated bacterial strains occurred after full pulsing regimes at the different lamp discharge energies tested, some repair was evident when using a combination of reduced pulsing at the lower lamp discharge energies. Strains harbouring genes for multiple resistances to antibiotics were not significantly more resistant to PL treatments. Slight temperature

  2. Bacterial cooperation in the wild and in the clinic: are pathogen social behaviours relevant outside the laboratory?

    Science.gov (United States)

    Harrison, Freya

    2013-02-01

    Individual bacterial cells can communicate via quorum sensing, cooperate to harvest nutrients from their environment, form multicellular biofilms, compete over resources and even kill one another. When the environment that bacteria inhabit is an animal host, these social behaviours mediate virulence. Over the last decade, much attention has focussed on the ecology, evolution and pathology of bacterial cooperation, and the possibility that it could be exploited or destabilised to treat infections. But how far can we really extrapolate from theoretical predictions and laboratory experiments to make inferences about 'cooperative' behaviours in hosts and reservoirs? To determine the likely importance and evolution of cooperation 'in the wild', several questions must be addressed. A recent paper that reports the dynamics of bacterial cooperation and virulence in a field experiment provides an excellent nucleus for bringing together key empirical and theoretical results which help us to frame - if not completely to answer - these questions.

  3. Assessment of the relevance of the antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine from Pantoea agglomerans biological control strains against bacterial plant pathogens

    Science.gov (United States)

    Sammer, Ulrike F; Reiher, Katharina; Spiteller, Dieter; Wensing, Annette; Völksch, Beate

    2012-01-01

    The epiphyte Pantoea agglomerans 48b/90 (Pa48b) is a promising biocontrol strain against economically important bacterial pathogens such as Erwinia amylovora. Strain Pa48b produces the broad-spectrum antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine (APV) in a temperature-dependent manner. An APV-negative mutant still suppressed the E. amylovora population and fire blight disease symptoms in apple blossom experiments under greenhouse conditions, but was inferior to the Pa48b wild-type indicating the influence of APV in the antagonism. In plant experiments with the soybean pathogen Pseudomonas syringae pv. glycinea both, Pa48b and the APV-negative mutant, successfully suppressed the pathogen. Our results demonstrate that the P. agglomerans strain Pa48b is an efficient biocontrol organism against plant pathogens, and we prove its ability for fast colonization of plant surfaces over a wide temperature range. PMID:23233458

  4. Antigenic Variation in Bacterial Pathogens.

    Science.gov (United States)

    Palmer, Guy H; Bankhead, Troy; Seifert, H Steven

    2016-02-01

    Antigenic variation is a strategy used by a broad diversity of microbial pathogens to persist within the mammalian host. Whereas viruses make use of a minimal proofreading capacity combined with large amounts of progeny to use random mutation for variant generation, antigenically variant bacteria have evolved mechanisms which use a stable genome, which aids in protecting the fitness of the progeny. Here, three well-characterized and highly antigenically variant bacterial pathogens are discussed: Anaplasma, Borrelia, and Neisseria. These three pathogens display a variety of mechanisms used to create the structural and antigenic variation needed for immune escape and long-term persistence. Intrahost antigenic variation is the focus; however, the role of these immune escape mechanisms at the population level is also presented.

  5. Formaldehyde stress responses in bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Nathan Houqian Chen

    2016-03-01

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

  6. Emerging bacterial pathogens: the past and beyond.

    Science.gov (United States)

    Vouga, M; Greub, G

    2016-01-01

    Since the 1950s, medical communities have been facing with emerging and reemerging infectious diseases, and emerging pathogens are now considered to be a major microbiologic public health threat. In this review, we focus on bacterial emerging diseases and explore factors involved in their emergence as well as future challenges. We identified 26 major emerging and reemerging infectious diseases of bacterial origin; most of them originated either from an animal and are considered to be zoonoses or from water sources. Major contributing factors in the emergence of these bacterial infections are: (1) development of new diagnostic tools, such as improvements in culture methods, development of molecular techniques and implementation of mass spectrometry in microbiology; (2) increase in human exposure to bacterial pathogens as a result of sociodemographic and environmental changes; and (3) emergence of more virulent bacterial strains and opportunistic infections, especially affecting immunocompromised populations. A precise definition of their implications in human disease is challenging and requires the comprehensive integration of microbiological, clinical and epidemiologic aspects as well as the use of experimental models. It is now urgent to allocate financial resources to gather international data to provide a better understanding of the clinical relevance of these waterborne and zoonotic emerging diseases.

  7. Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses

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    Domann Eugen

    2011-02-01

    Full Text Available Abstract Background Black elderberries (Sambucus nigra L. are well known as supportive agents against common cold and influenza. It is further known that bacterial super-infection during an influenza virus (IV infection can lead to severe pneumonia. We have analyzed a standardized elderberry extract (Rubini, BerryPharma AG for its antimicrobial and antiviral activity using the microtitre broth micro-dilution assay against three Gram-positive bacteria and one Gram-negative bacteria responsible for infections of the upper respiratory tract, as well as cell culture experiments for two different strains of influenza virus. Methods The antimicrobial activity of the elderberry extract was determined by bacterial growth experiments in liquid cultures using the extract at concentrations of 5%, 10%, 15% and 20%. The inhibitory effects were determined by plating the bacteria on agar plates. In addition, the inhibitory potential of the extract on the propagation of human pathogenic H5N1-type influenza A virus isolated from a patient and an influenza B virus strain was investigated using MTT and focus assays. Results For the first time, it was shown that a standardized elderberry liquid extract possesses antimicrobial activity against both Gram-positive bacteria of Streptococcus pyogenes and group C and G Streptococci, and the Gram-negative bacterium Branhamella catarrhalis in liquid cultures. The liquid extract also displays an inhibitory effect on the propagation of human pathogenic influenza viruses. Conclusion Rubini elderberry liquid extract is active against human pathogenic bacteria as well as influenza viruses. The activities shown suggest that additional and alternative approaches to combat infections might be provided by this natural product.

  8. Use of Bacteriophages to control bacterial pathogens

    Science.gov (United States)

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

  9. Proteomics of Foodborne Bacterial Pathogens

    Science.gov (United States)

    Fagerquist, Clifton K.

    This chapter is intended to be a relatively brief overview of proteomic techniques currently in use for the identification and analysis of microorganisms with a special emphasis on foodborne pathogens. The chapter is organized as follows. First, proteomic techniques are introduced and discussed. Second, proteomic applications are presented specifically as they relate to the identification and qualitative/quantitative analysis of foodborne pathogens.

  10. Photoinactivation of major bacterial pathogens in aquaculture

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    Heyong Jin Roh

    2016-08-01

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

  11. Molecular Mechanisms of Bacterial Pathogenicity

    Science.gov (United States)

    Fuchs, Thilo Martin

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

  12. TEACHING HOSPITAL: COMMON BACTERIAL PATHOGENS SEEN.

    African Journals Online (AJOL)

    2006-06-27

    Jun 27, 2006 ... Nigerian Journal of Clinical Practice ... Background: Bacterial infections are important causes of morbidity in the neonatal period. ... Streptococcus pneumoniae and Pseudomonas are the least encountered in this series ... pathogens in pyogenic meningitis. .... skin infection 85 (10.5%) and diarrhea! vomiting.

  13. Insights from genomics into bacterial pathogen populations.

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    Daniel J Wilson

    2012-09-01

    Full Text Available Bacterial pathogens impose a heavy burden of disease on human populations worldwide. The gravest threats are posed by highly virulent respiratory pathogens, enteric pathogens, and HIV-associated infections. Tuberculosis alone is responsible for the deaths of 1.5 million people annually. Treatment options for bacterial pathogens are being steadily eroded by the evolution and spread of drug resistance. However, population-level whole genome sequencing offers new hope in the fight against pathogenic bacteria. By providing insights into bacterial evolution and disease etiology, these approaches pave the way for novel interventions and therapeutic targets. Sequencing populations of bacteria across the whole genome provides unprecedented resolution to investigate (i within-host evolution, (ii transmission history, and (iii population structure. Moreover, advances in rapid benchtop sequencing herald a new era of real-time genomics in which sequencing and analysis can be deployed within hours in response to rapidly changing public health emergencies. The purpose of this review is to highlight the transformative effect of population genomics on bacteriology, and to consider the prospects for answering abiding questions such as why bacteria cause disease.

  14. Antibiotic resistance in ocular bacterial pathogens

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    S Sharma

    2011-01-01

    Full Text Available Bacterial infections of the eye are common and ophthalmologists are spoilt for choice with a variety of antibiotics available in the market. Antibiotics can be administered in the eye by a number of routes; topical, subconjunctival, subtenon and intraocular. Apart from a gamut of eye drops available, ophthalmologists also have the option of preparing fortified eye drops from parenteral formulations, thereby, achieving high concentrations; often much above the minimum inhibitory concentration (MIC, of antibiotics in ocular tissues during therapy. Antibiotic resistance among ocular pathogens is increasing in parallel with the increase seen over the years in bacteria associated with systemic infections. Although it is believed that the rise in resistant ocular bacterial isolates is linked to the rise in resistant systemic pathogens, recent evidence has correlated the emergence of resistant bacteria in the eye to prior topical antibiotic therapy. One would like to believe that either of these contributes to the emergence of resistance to antibiotics among ocular pathogens. Until recently, ocular pathogens resistant to fluoroquinolones have been minimal but the pattern is currently alarming. The new 8-fluoroquinolone on the scene-besifloxacin, is developed exclusively for ophthalmic use and it is hoped that it will escape the selective pressure for resistance because of lack of systemic use. In addition to development of new antibacterial agents, the strategies to halt or control further development of resistant ocular pathogens should always include judicious use of antibiotics in the treatment of human, animal or plant diseases.

  15. Clostridium difficile is an autotrophic bacterial pathogen.

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    Michael Köpke

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

  16. Bacterial toxins as pathogen weapons against phagocytes

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    Ana edo Vale

    2016-02-01

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

  17. Bacterial Toxins as Pathogen Weapons Against Phagocytes.

    Science.gov (United States)

    do Vale, Ana; Cabanes, Didier; Sousa, Sandra

    2016-01-01

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

  18. Russian vaccines against especially dangerous bacterial pathogens

    Science.gov (United States)

    Feodorova, Valentina A; Sayapina, Lidiya V; Corbel, Michael J; Motin, Vladimir L

    2014-01-01

    In response to the epidemiological situation, live attenuated or killed vaccines against anthrax, brucellosis, cholera, glanders, plague and tularemia were developed and used for immunization of at-risk populations in the Former Soviet Union. Certain of these vaccines have been updated and currently they are used on a selective basis, mainly for high risk occupations, in the Russian Federation. Except for anthrax and cholera these vaccines currently are the only licensed products available for protection against the most dangerous bacterial pathogens. Development of improved formulations and new products is ongoing. PMID:26038506

  19. Water microbiology. Bacterial pathogens and water.

    Science.gov (United States)

    Cabral, João P S

    2010-10-01

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

  20. Water Microbiology. Bacterial Pathogens and Water

    Directory of Open Access Journals (Sweden)

    João P. S. Cabral

    2010-10-01

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

  1. Pathogenic bacterial contaminations in hospital cafeteria foods.

    Science.gov (United States)

    Rattanasena, Paweena; Somboonwatthanakul, Issaraporn

    2010-02-01

    This study aims to examine the pathogenic bacterial contaminations in foods sold in hospital cafeteria. A study was conducted between April and September of 2008 using cafeteria located in Mahasarakham provincial hospital, Thailand, as a study area. The cafeteria foods were evaluated for contaminations with Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Streptococcus faecalis, which have been earlier reported to cause nosocomial outbreaks. Of 33 different types of ready-to-eat foods, the majority (54.54%) were found to have bacteria >10(7) colony forming units per gram of food (cfu g(-1)), whereas 36.36% and only 9.10% of them were found to have bacteria at 10(6)-10(7) and cafeteria were contaminated with several pathogenic bacteria at unacceptable levels. Healthcare authorities should be more aware that ready-to-eat cafeteria foods that are heavily contaminated with pathogenic bacteria may be harmful to healthcare workers and visitors and may result in nosocomial infections of the patients.

  2. Shellfish as reservoirs of bacterial pathogens

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    Harry Hariharan

    2016-04-01

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

  3. Shellifsh as reservoirs of bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Harry Hariharan; Victor Amadi

    2016-01-01

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

  4. The Neglected Intrinsic Resistome of Bacterial Pathogens

    Science.gov (United States)

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

    2008-01-01

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

  5. The neglected intrinsic resistome of bacterial pathogens.

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    Alicia Fajardo

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

  6. Evolution of Bacterial Pathogens within the Human Host

    OpenAIRE

    Bliven, Kimberly A.; Maurelli, Anthony T.

    2016-01-01

    Selective pressures within the human host, including interactions with innate and adaptive immune responses, exposure to medical interventions such as antibiotics, and competition with commensal microbiota all facilitate the evolution of bacterial pathogens. In this chapter, we present examples of pathogen strategies which emerged as a result of selective pressures within the human host niche, and discuss the resulting co-evolutionary ‘arms race’ between these organisms. In bacterial pathogen...

  7. [3] Diseases Caused By Bacterial Pathogens In Inland Water

    OpenAIRE

    若林, 久嗣; 吉田, 照豊; 野村, 哲一; 中井, 敏博; 高野, 倫一

    2016-01-01

    Bacterial diseases cause huge damages in fish farms worldwide, and numerous bacterial pathogens from inland and saline waters have been identified and studied for their characterization, diagnosis, prevention and control. In this chapter, eight important fish diseases viz. 1) streptococcosis (inland water), 2) furunculosis, 3) bacterial gill disease, 4) columnaris disease, 5) bacterial cold-water disease, 6) red spot disease, 7) edwardsiellosis (Edwardsiella ictaluri), and 8) motile aeromonad...

  8. Diagnostics and Resistance Profiling of Bacterial Pathogens.

    Science.gov (United States)

    Hornischer, Klaus; Häußler, Susanne

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

  9. Antibiotic Susceptibility and Immunomodulatory Potential of Chosen Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    M. Sujatha

    2010-01-01

    Full Text Available Problem statement: Antibiotic susceptibility is still the best way for bacterial pathogen escape mechanism against immunity. Approach: In the present investigation, bacterial pathogens like Staphylococcus aureus, Escherichia coli, Aeromonas hydrophila, Klebsiella and Pseudomonas aeruginosa were used to screen antibiotic susceptibility and immunomodulatory potential. Results: All the test pathogens were sensitive to all the test antibiotics 11±2 mm except penicillin. The conditions for the preparation of antigens of intact natural composition and conformation from pathogens (whole cell and heat killed, were determined using Swiss albino mice (Balb/C as experimental species. Immunomodulatory potential of test pathogens were screened using animal model. Test pathogen decreases the body weight comparing that of normal mice, some notable changes were also noted in activity, growth, water consumption, feed consumption. Antibody titre level in animal serum decreased upto 50% in whole cell pathogen and heat killed pathogen treated animals. Conclusion: The five pathogens administered animals, decrement in B-lymphocyte was much pronounced in Pseudomonas aeruginosa followed by Escherichia coli, Staphylococcus aureus, Klebsiella sp., Aeromonas hydrophila in the 5 week. Pathogen treated mice showed an IgG suppressive effect. It is found to be suppressive to T cell production, so induction in cell mediated immunity has confirmed pathogenic potential of test pathogens. All these test pathogenic strains were remarkably suppressing immune system of pathogen exposed animals.

  10. Evolution of Bacterial Pathogens Within the Human Host.

    Science.gov (United States)

    Bliven, Kimberly A; Maurelli, Anthony T

    2016-02-01

    Selective pressures within the human host, including interactions with innate and adaptive immune responses, exposure to medical interventions such as antibiotics, and competition with commensal microbiota all facilitate the evolution of bacterial pathogens. In this chapter, we present examples of pathogen strategies that emerged as a result of selective pressures within the human host niche and discuss the resulting coevolutionary "arms race" between these organisms. In bacterial pathogens, many of the genes responsible for these strategies are encoded on mobile pathogenicity islands or plasmids, underscoring the importance of horizontal gene transfer in the emergence of virulent microbial species.

  11. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    Directory of Open Access Journals (Sweden)

    Dongsheng Che

    2014-01-01

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

  12. Investigation of septins using infection by bacterial pathogens.

    Science.gov (United States)

    Krokowski, S; Mostowy, S

    2016-01-01

    Investigation of the host cytoskeleton during infection by bacterial pathogens has significantly contributed to our understanding of cell biology and host defense. Work has shown that septins are recruited to the phagocytic cup as collarlike structures and enable bacterial entry into host cells. In the cytosol, septins can entrap actin-polymerizing bacteria in cage-like structures for targeting to autophagy, a highly conserved intracellular degradation process. In this chapter, we describe methods to investigate septin assembly and function during infection by bacterial pathogens. Use of these methods can lead to in-depth understanding of septin biology and suggest therapeutic approaches to combat infectious disease.

  13. The diversity of bacterial pathogenicity mechanisms.

    Science.gov (United States)

    Rosenberg, Eugene

    2005-01-01

    A report on the international conference 'Molecular basis of bacterial pathogenesis', sponsored by the Federation of European Microbiological Societies (FEMS) and the Israel Center for the Study of Emerging Diseases, Ein Gedi, Israel, 23-27 January 2005.

  14. Genomic and Transcriptomic Analyses of Foodborne Bacterial Pathogens

    Science.gov (United States)

    Zhang, Wei; Dudley, Edward G.; Wade, Joseph T.

    DNA microarrays (often interchangeably called DNA chips or DNA arrays) are among the most popular analytical tools for high-throughput comparative genomic and transcriptomic analyses of foodborne bacterial pathogens. A typical DNA microarray contains hundreds to millions of small DNA probes that are chemically attached (or "printed") onto the surface of a microscopic glass slide. Depending on the specific "printing" and probe synthesis technologies for different microarray platforms, such DNA probes can be PCR amplicons or in situ synthesized short oligonucleotides. DNA microarray technologies have revolutionized the way that we investigate the biology of foodborne bacterial pathogens. The major advantage of these technologies is that DNA microarrays allow comparison of subtle genomic or transcriptomic variations between two bacterial samples, such as genomic variations between two different bacterial strains or transcriptomic alterations of same bacterial strain under two different treatments. Some applications of comparative genomic hybridization microarrays and global gene expression microarrays have been covered in previous chapters of this book.

  15. Looking in ticks for human bacterial pathogens.

    Science.gov (United States)

    Mediannikov, O; Fenollar, F

    2014-12-01

    Ticks are considered to be second worldwide to mosquitoes as vectors of human diseases and the most important vectors of disease-causing pathogens in domestic and wild animals. A number of emerging tick-borne pathogens are already discovered; however, the proportion of undiagnosed infectious diseases, especially in tropical regions, may suggest that there are still more pathogens associated with ticks. Moreover, the identification of bacteria associated with ticks may provide new tool for the control of ticks and tick-borne diseases. Described here molecular methods of screening of ticks, extensive use of modern culturomics approach, newly developed artificial media and different cell line cultures may significantly improve our knowledge about the ticks as the agents of human and animal pathology.

  16. Bacteriophages for detection and control of bacterial pathogens in food and food-processing environment.

    Science.gov (United States)

    Brovko, Lubov Y; Anany, Hany; Griffiths, Mansel W

    2012-01-01

    This chapter presents recent advances in bacteriophage research and their application in the area of food safety. Section 1 describes general facts on phage biology that are relevant to their application for control and detection of bacterial pathogens in food and environmental samples. Section 2 summarizes the recently acquired data on application of bacteriophages to control growth of bacterial pathogens and spoilage organisms in food and food-processing environment. Section 3 deals with application of bacteriophages for detection and identification of bacterial pathogens. Advantages of bacteriophage-based methods are presented and their shortcomings are discussed. The chapter is intended for food scientist and food product developers, and people in food inspection and health agencies with the ultimate goal to attract their attention to the new developing technology that has a tremendous potential in providing means for producing wholesome and safe food.

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

    Science.gov (United States)

    Mellouk, Nora; Enninga, Jost

    2016-01-01

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

  18. Recognition of bacterial plant pathogens: local, systemic and transgenerational immunity.

    Science.gov (United States)

    Henry, Elizabeth; Yadeta, Koste A; Coaker, Gitta

    2013-09-01

    Bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. The plant innate immune system comprises extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (NLR) proteins that recognize specific bacterial effectors delivered into host cells. Plants lack the adaptive immune branch present in animals, but still afford flexibility to pathogen attack through systemic and transgenerational resistance. Here, we focus on current research in plant immune responses against bacterial pathogens. Recent studies shed light onto the activation and inactivation of pattern recognition receptors and systemic acquired resistance. New research has also uncovered additional layers of complexity surrounding NLR immune receptor activation, cooperation and sub-cellular localizations. Taken together, these recent advances bring us closer to understanding the web of molecular interactions responsible for coordinating defense responses and ultimately resistance.

  19. Bats as reservoir hosts of human bacterial pathogen, Bartonella mayotimonensis.

    Science.gov (United States)

    Veikkolainen, Ville; Vesterinen, Eero J; Lilley, Thomas M; Pulliainen, Arto T

    2014-06-01

    A plethora of pathogenic viruses colonize bats. However, bat bacterial flora and its zoonotic threat remain ill defined. In a study initially conducted as a quantitative metagenomic analysis of the fecal bacterial flora of the Daubenton's bat in Finland, we unexpectedly detected DNA of several hemotrophic and ectoparasite-transmitted bacterial genera, including Bartonella. Bartonella spp. also were either detected or isolated from the peripheral blood of Daubenton's, northern, and whiskered bats and were detected in the ectoparasites of Daubenton's, northern, and Brandt's bats. The blood isolates belong to the Candidatus-status species B. mayotimonensis, a recently identified etiologic agent of endocarditis in humans, and a new Bartonella species (B. naantaliensis sp. nov.). Phylogenetic analysis of bat-colonizing Bartonella spp. throughout the world demonstrates a distinct B. mayotimonensis cluster in the Northern Hemisphere. The findings of this field study highlight bats as potent reservoirs of human bacterial pathogens.

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

    Science.gov (United States)

    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

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

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

    Science.gov (United States)

    Arenas, Yaxal; Mandel, Arkady; Lilge, Lothar

    2012-03-01

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

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

    Science.gov (United States)

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

  3. Unraveling Plant Responses to Bacterial Pathogens through Proteomics

    Directory of Open Access Journals (Sweden)

    Tamara Zimaro

    2011-01-01

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

  4. Methods to classify bacterial pathogens in cystic fibrosis

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  5. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara

    2011-11-03

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

  6. [Bacterial genomics and metagenomics: clinical applications and medical relevance].

    Science.gov (United States)

    Diene, S M; Bertelli, C; Pillonel, T; Schrenzel, J; Greub, G

    2014-11-12

    New sequencing technologies provide in a short time and at low cost high amount of genomic sequences useful for applications such as: a) development of diagnostic PCRs and/or serological tests; b) detection of virulence factors (virulome) or genes/SNPs associated with resistance to antibiotics (resistome) and c) investigation of transmission and dissemination of bacterial pathogens. Thus, bacterial genomics of medical importance is useful to clinical microbiologists, to infectious diseases specialists as well as to epidemiologists. Determining the microbial composition of a sample by metagenomics is another application of new sequencing technologies, useful to understand the impact of bacteria on various non-infectious diseases such as obesity, asthma, or diabetes. Genomics and metagenomics will likely become a specialized diagnostic analysis.

  7. Bacterial genome engineering and synthetic biology: combating pathogens.

    Science.gov (United States)

    Krishnamurthy, Malathy; Moore, Richard T; Rajamani, Sathish; Panchal, Rekha G

    2016-11-04

    The emergence and prevalence of multidrug resistant (MDR) pathogenic bacteria poses a serious threat to human and animal health globally. Nosocomial infections and common ailments such as pneumonia, wound, urinary tract, and bloodstream infections are becoming more challenging to treat due to the rapid spread of MDR pathogenic bacteria. According to recent reports by the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC), there is an unprecedented increase in the occurrence of MDR infections worldwide. The rise in these infections has generated an economic strain worldwide, prompting the WHO to endorse a global action plan to improve awareness and understanding of antimicrobial resistance. This health crisis necessitates an immediate action to target the underlying mechanisms of drug resistance in bacteria. The advent of new bacterial genome engineering and synthetic biology (SB) tools is providing promising diagnostic and treatment plans to monitor and treat widespread recalcitrant bacterial infections. Key advances in genetic engineering approaches can successfully aid in targeting and editing pathogenic bacterial genomes for understanding and mitigating drug resistance mechanisms. In this review, we discuss the application of specific genome engineering and SB methods such as recombineering, clustered regularly interspaced short palindromic repeats (CRISPR), and bacterial cell-cell signaling mechanisms for pathogen targeting. The utility of these tools in developing antibacterial strategies such as novel antibiotic production, phage therapy, diagnostics and vaccine production to name a few, are also highlighted. The prevalent use of antibiotics and the spread of MDR bacteria raise the prospect of a post-antibiotic era, which underscores the need for developing novel therapeutics to target MDR pathogens. The development of enabling SB technologies offers promising solutions to deliver safe and effective antibacterial therapies.

  8. Detection of foodborne bacterial pathogens from individual filth flies.

    Science.gov (United States)

    Pava-Ripoll, Monica; Pearson, Rachel E G; Miller, Amy K; Ziobro, George C

    2015-02-13

    There is unanimous consensus that insects are important vectors of foodborne pathogens. However, linking insects as vectors of the pathogen causing a particular foodborne illness outbreak has been challenging. This is because insects are not being aseptically collected as part of an environmental sampling program during foodborne outbreak investigations and because there is not a standardized method to detect foodborne bacteria from individual insects. To take a step towards solving this problem, we adapted a protocol from a commercially available PCR-based system that detects foodborne pathogens from food and environmental samples, to detect foodborne pathogens from individual flies.Using this standardized protocol, we surveyed 100 wild-caught flies for the presence of Cronobacter spp., Salmonella enterica, and Listeria monocytogenes and demonstrated that it was possible to detect and further isolate these pathogens from the body surface and the alimentary canal of a single fly. Twenty-two percent of the alimentary canals and 8% of the body surfaces from collected wild flies were positive for at least one of the three foodborne pathogens. The prevalence of Cronobacter spp. on either body part of the flies was statistically higher (19%) than the prevalence of S. enterica (7%) and L.monocytogenes (4%). No false positives were observed when detecting S. enterica and L. monocytogenes using this PCR-based system because pure bacterial cultures were obtained from all PCR-positive results. However, pure Cronobacter colonies were not obtained from about 50% of PCR-positive samples, suggesting that the PCR-based detection system for this pathogen cross-reacts with other Enterobacteriaceae present among the highly complex microbiota carried by wild flies. The standardized protocol presented here will allow laboratories to detect bacterial foodborne pathogens from aseptically collected insects, thereby giving public health officials another line of evidence to find out how

  9. Lifestyles of the effector-rich: genome-enabled characterization of bacterial plant pathogens

    Science.gov (United States)

    Genome sequencing of bacterial plant pathogens is providing transformative insights into the complex network of molecular plant-microbe interactions mediated by extracellular effectors during pathogenesis. Bacterial pathogens sequenced to completion are phylogenetically diverse and vary significant...

  10. Bacteriophage functional genomics and its role in bacterial pathogen detection.

    Science.gov (United States)

    Klumpp, Jochen; Fouts, Derrick E; Sozhamannan, Shanmuga

    2013-07-01

    Emerging and reemerging bacterial infectious diseases are a major public health concern worldwide. The role of bacteriophages in the emergence of novel bacterial pathogens by horizontal gene transfer was highlighted by the May 2011 Escherichia coli O104:H4 outbreaks that originated in Germany and spread to other European countries. This outbreak also highlighted the pivotal role played by recent advances in functional genomics in rapidly deciphering the virulence mechanism elicited by this novel pathogen and developing rapid diagnostics and therapeutics. However, despite a steady increase in the number of phage sequences in the public databases, boosted by the next-generation sequencing technologies, few functional genomics studies of bacteriophages have been conducted. Our definition of 'functional genomics' encompasses a range of aspects: phage genome sequencing, annotation and ascribing functions to phage genes, prophage identification in bacterial sequences, elucidating the events in various stages of phage life cycle using genomic, transcriptomic and proteomic approaches, defining the mechanisms of host takeover including specific bacterial-phage protein interactions and identifying virulence and other adaptive features encoded by phages and finally, using prophage genomic information for bacterial detection/diagnostics. Given the breadth and depth of this definition and the fact that some of these aspects (especially phage-encoded virulence/adaptive features) have been treated extensively in other reviews, we restrict our focus only on certain aspects. These include phage genome sequencing and annotation, identification of prophages in bacterial sequences and genetic characterization of phages, functional genomics of the infection process and finally, bacterial identification using genomic information.

  11. Relationship between lactobacilli and opportunistic bacterial pathogens associated with vaginitis

    OpenAIRE

    Razzak, Mohammad Sabri A.; Alaa H. Al-Charrakh; Bara Hamid AL-Greitty

    2011-01-01

    Background: Vaginitis, is an infectious inflammation of the vaginal mucosa, which sometimes involves the vulva. The balance of the vaginal flora is maintained by the Lactobacilli and its protective and probiotic role in treating and preventing vaginal infection by producing antagonizing compounds which are regarded as safe for humans. Aim: The aim of this study was to evaluate the protective role of Lactobacilli against common bacterial opportunistic pathogens in vaginitis and study the effec...

  12. Bacterial pathogen phytosensing in transgenic tobacco and Arabidopsis plants.

    Science.gov (United States)

    Liu, Wusheng; Mazarei, Mitra; Rudis, Mary R; Fethe, Michael H; Peng, Yanhui; Millwood, Reginald J; Schoene, Gisele; Burris, Jason N; Stewart, C Neal

    2013-01-01

    Plants are subject to attack by a wide range of phytopathogens. Current pathogen detection methods and technologies are largely constrained to those occurring post-symptomatically. Recent efforts were made to generate plant sentinels (phytosensors) that can be used for sensing and reporting pathogen contamination in crops. Engineered phytosensors indicating the presence of plant pathogens as early-warning sentinels potentially have tremendous utility as wide-area detectors. We previously showed that synthetic promoters containing pathogen and/or defence signalling inducible cis-acting regulatory elements (RE) fused to a fluorescent protein (FP) reporter could detect phytopathogenic bacteria in a transient phytosensing system. Here, we further advanced this phytosensing system by developing stable transgenic tobacco and Arabidopsis plants containing candidate constructs. The inducibility of each synthetic promoter was examined in response to biotic (bacterial pathogens) or chemical (plant signal molecules salicylic acid, ethylene and methyl jasmonate) treatments using stably transgenic plants. The treated plants were visualized using epifluorescence microscopy and quantified using spectrofluorometry for FP synthesis upon induction. Time-course analyses of FP synthesis showed that both transgenic tobacco and Arabidopsis plants were capable to respond in predictable ways to pathogen and chemical treatments. These results provide insights into the potential applications of transgenic plants as phytosensors and the implementation of emerging technologies for monitoring plant disease outbreaks in agricultural fields.

  13. Temperature dependent bacteriophages of a tropical bacterial pathogen

    Science.gov (United States)

    Shan, Jinyu; Korbsrisate, Sunee; Withatanung, Patoo; Adler, Natalie Lazar; Clokie, Martha R. J.; Galyov, Edouard E.

    2014-01-01

    There is an increasing awareness of the multiple ways that bacteriophages (phages) influence bacterial evolution, population dynamics, physiology, and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model B. thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C), the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C), the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial biology, and on our ability to culture and correctly enumerate viable bacteria. PMID:25452746

  14. Temperature dependent bacteriophages of a tropical bacterial pathogen

    Directory of Open Access Journals (Sweden)

    Martha Rebecca Jane Clokie

    2014-11-01

    Full Text Available There is an increasing awareness of the multiple ways that bacteriophages (phages influence bacterial evolution, population dynamics, physiology and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model Burkholderia thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C, the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C, the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial life, and on our ability to culture and correctly enumerate viable bacteria.

  15. Investigation of magnetic microdiscs for bacterial pathogen detection

    Science.gov (United States)

    Castillo-Torres, Keisha Y.; Garraud, Nicolas; Arnold, David P.; McLamore, Eric S.

    2016-05-01

    Despite strict regulations to control the presence of human pathogens in our food supply, recent foodborne outbreaks have heightened public concern about food safety and created urgency to improve methods for pathogen detection. Herein we explore a potentially portable, low-cost system that uses magnetic microdiscs for the detection of bacterial pathogens in liquid samples. The system operates by optically measuring the rotational dynamics of suspended magnetic microdiscs functionalized with pathogen-binding aptamers. The soft ferromagnetic (Ni80Fe20) microdiscs exhibit a closed magnetic spin arrangement (i.e. spin vortex) with zero magnetic stray field, leading to no disc agglomeration when in free suspension. With very high surface area for functionalization and volumes 10,000x larger than commonly used superparamagnetic nanoparticles, these 1.5-μm-diameter microdiscs are well suited for tagging, trapping, actuating, or interrogating bacterial targets. This work reports a wafer-level microfabrication process for fabrication of 600 million magnetic microdiscs per substrate and measurement of their rotational dynamics response. Additionally, the biofunctionalization of the microdiscs with DNA aptamers, subsequent binding to E. coli bacteria, and their magnetic manipulation is reported.

  16. Protease-dependent mechanisms of complement evasion by bacterial pathogens.

    Science.gov (United States)

    Potempa, Michal; Potempa, Jan

    2012-09-01

    The human immune system has evolved a variety of mechanisms for the primary task of neutralizing and eliminating microbial intruders. As the first line of defense, the complement system is responsible for rapid recognition and opsonization of bacteria, presentation to phagocytes and bacterial cell killing by direct lysis. All successful human pathogens have mechanisms of circumventing the antibacterial activity of the complement system and escaping this stage of the immune response. One of the ways in which pathogens achieve this is the deployment of proteases. Based on the increasing number of recent publications in this area, it appears that proteolytic inactivation of the antibacterial activities of the complement system is a common strategy of avoiding targeting by this arm of host innate immune defense. In this review, we focus on those bacteria that deploy proteases capable of degrading complement system components into non-functional fragments, thus impairing complement-dependent antibacterial activity and facilitating pathogen survival inside the host.

  17. Production of transgenic medaka with increased resistance to bacterial pathogens.

    Science.gov (United States)

    Sarmasik, Aliye; Warr, Gregory; Chen, Thomas T

    2002-06-01

    Cecropins, first identified in silk moth (Hyalophora cecropia), are a group of antimicrobial peptides with bactericidal activity against a broad spectrum of bacteria. In this study we investigated whether (1) this group of antimicrobial peptides could exhibit bactericidal activity toward known fish bacterial pathogens and (2) expression of cecropin transgenes in transgenic medaka (Oryzias latipas) could result in increasing resistance of the transgenic fish to infection by fish bacterial pathogens. Cecropin gene construct containing silk moth preprocecropin B, procecropin B and cecropin B, and porcine cecropin P1 driven by a cytomegalovirus (CMV) promoter were transfected into chinook salmon embryonic cells (CHSE-214) by lipofection, and the resulting permanent transformants were collected. In an "inhibition zone" assay medium isolated from each transformant exhibited strong bactericidal activity toward known fish bacterial pathogens such as Pseudomonas fluorescens, Aeromonas hydrophila, and Vibrio anguillarum. The same cecropin transgene constructs were introduced into newly fertilized medaka eggs by electroporation to produce transgenic fish. About 40% to 60% of the embryos survived from electroporation, and about 5% to 11% of the surviving fish were shown to contain cecropin transgenes by polymerase chain reaction analysis of genomic DNA samples isolated from presumptive transgenic fish. These P1 transgenic fish were used as founder stocks, and following generations of successive breeding, a total of 20 F2 families of transgenic fish were established. Expression of cecropin transgenes was detected in the F2 transgenics by reverse transcriptase polymerase chain reaction analysis. Southern blot analysis of genomic DNA isolated from different F2 fish showed that cecropin transgenes were integrated into the genomes of F2 transgenic fish. To determine whether transgenic fish carrying cecropin transgenes could exhibit resistance to infection by known fish bacterial

  18. Prediction of Genomic Islands in Three Bacterial Pathogens of Pneumonia

    Directory of Open Access Journals (Sweden)

    Wen Wei

    2012-03-01

    Full Text Available Pneumonia is one kind of common infectious disease, which is usually caused by bacteria, viruses, or fungi. In this paper, we predicted genomic islands in three bacterial pathogens of pneumonia. They are Chlamydophila pneumoniae, Mycoplasma pneumoniae and Streptococcus pneumoniae, respectively. For each pathogen, one clinical strain is involved. After implementing the cumulative GC profile combined with h and BCN index, eight genomic islands are found in three pathogens. Among them, six genomic islands are found to have mobility elements, which constitute a kind of conserved character of genomic islands, and this introduces the possibility that they are genuine genomic islands. The present results show that the cumulative GC profile when combined with h and BCN indexes is a good method for predicting genomic islands in bacteria and it has lower false positive rate than the SIGI method. Specially, three genomic islands are found to contain clusters of genes coding for production of virulence factors and this is useful for research into the pathogenicity of these pathogens and helpful for the treatment of diseases caused by them.

  19. Molecular Detection of Common Bacterial Pathogens Causing Meningitis

    Directory of Open Access Journals (Sweden)

    H Sadighian

    2009-03-01

    Full Text Available "nBackground: The clinical diagnosis of meningitis is crucial, particularly in children. The early diagnosis and empiric an­tibi­otic treatments have led to a reduction in morbidity and mortality rates. PCR and the enzymatic digestion of 16SrDNA frag­ment which is produced by universal primers led up fast and sensitive determination. The purpose of this study was to investi­gate a rapid method for detection of common bacterial pathogens causing meningitis."nMethods: According to the gene encoding 16SrDNA found in all bacteria, a pair of primers was designed. Then the univer­sal PCR was performed for bacterial agents of meningitis (Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influ­enzae, etc. by employing broad- range DNA extraction method. The ob­tained uni­versal PCR products were digested with restriction enzymes (HaeIII, AluI and MnlI to identify bacterial species. "nResults: By the enzymatic digestion of the universal products of each standard strain of the above bacteria, specific patterns were achieved. These specific patterns may be used for comparison in CSF examination. The analytical sensitivity of the as­say was approximately 1.5´102 CFU/ml of CSF even in samples with high amount of proteins. Conclusion: The universal PCR coupled with enzymatic digestion can be used to detect and identify bacterial pathogens in clini­cal specimens rapidly and accurately. Molecular diagnostic of bacterial meningitis, though expensive and labor-inten­sive, but is valuable and critical in patient management.

  20. Fluorescence spectroscopy for rapid detection and classification of bacterial pathogens.

    Science.gov (United States)

    Sohn, Miryeong; Himmelsbach, David S; Barton, Franklin E; Fedorka-Cray, Paula J

    2009-11-01

    This study deals with the rapid detection and differentiation of Escherichia coli, Salmonella, and Campylobacter, which are the most commonly identified commensal and pathogenic bacteria in foods, using fluorescence spectroscopy and multivariate analysis. Each bacterial sample cultured under controlled conditions was diluted in physiologic saline for analysis. Fluorescence spectra were collected over a range of 200-700 nm with 0.5 nm intervals on the PerkinElmer Fluorescence Spectrometer. The synchronous scan technique was employed to find the optimum excitation (lambda(ex)) and emission (lambda(em)) wavelengths for individual bacteria with the wavelength interval (Deltalambda) being varied from 10 to 200 nm. The synchronous spectra and two-dimensional plots showed two maximum lambda(ex) values at 225 nm and 280 nm and one maximum lambda(em) at 335-345 nm (lambda(em) = lambda(ex) + Deltalambda), which correspond to the lambda(ex) = 225 nm, Deltalambda = 110-120 nm, and lambda(ex) = 280 nm, Deltalambda = 60-65 nm. For all three bacterial genera, the same synchronous scan results were obtained. The emission spectra from the three bacteria groups were very similar, creating difficulty in classification. However, the application of principal component analysis (PCA) to the fluorescence spectra resulted in successful classification of the bacteria by their genus as well as determining their concentration. The detection limit was approximately 10(3)-10(4) cells/mL for each bacterial sample. These results demonstrated that fluorescence spectroscopy, when coupled with PCA processing, has the potential to detect and to classify bacterial pathogens in liquids. The methodology is rapid (>10 min), inexpensive, and requires minimal sample preparation compared to standard analytical methods for bacterial detection.

  1. Genome Assembly and Computational Analysis Pipelines for Bacterial Pathogens

    KAUST Repository

    Rangkuti, Farania Gama Ardhina

    2011-06-01

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

  2. Pneumonia relevant to lung transplantation and pathogen distribution

    Institute of Scientific and Technical Information of China (English)

    HE Xuan; DAI Hua-ping; CHEN Qi-rui; MIAO Jin-bai; SUN Bing; BAO Na; HU Bin

    2013-01-01

    Background Pneumonia is the most common cause of morbidity and mortality in lung transplant (LT) recipients.The aim of the present study was to evaluate the incidence,etiology,risk factors and prognosis of pneumonia in LT recipients.Methods The LT cohort consisted of 28 recipients receiving LT in Beijing Chao-Yang Hospital from August 2005 to April 2011.Data collected included demographic data,underlying disorders,time and type of transplant,follow-up information,date of last follow-up,and patient status.A retrospective analysis was made of observational data that were prospectively collected.Results Twenty-two patients of 28 LT recipients had 47 episodes of pneumonia throughout the study period.Thirtyeight episodes of pneumonia in 19 recipients occurred post-LT with a median follow-up of 257.5 days (1-2104 days),the incidence of pneumonia was 192.4 episodes per 100 LT/year and its median time of onset was 100.5 days (0-946 days) post-transplantation.Bacteria,virus and fungi accounted for 62%,16% and 15% of the microbial pathogens,respectively.The most frequent were Pseudomonas aeruginosa (20%),cytomegalovirus (CMV) (15%),and Aspergillus fumigatus (10%).A total of 29% (11/38) of pneumonias occurred in the first month post-LT,and then the incidence decreased gradually.The incidence of CMV pneumonia was 25% (7/28) with a median time of 97 days (10-971 days).More than one bacterial infection and CMV infection were independent risk factors for aspergillus infection.The incidence of pulmonary tuberculosis (TB) was 18% (5/28),and the history of TB was a risk factor for TB relapse.There were 58% (7/12) of recipients who died of infection,and 71% (5/7) of these died in the first year after LT.Conclusions Pneumonia is still a major cause of morbidity and mortality in LT recipients.The most frequent microorganisms were Pseudomonas aeruginosa,CMV,and Aspergillus fumigates.The incidence of CMV pneumonia decreases with a delayed median time of onset

  3. Molecular versus conventional culture for detection of respiratory bacterial pathogens in poultry.

    Science.gov (United States)

    Ammar, A M; Abd El-Aziz, N K; Abd El Wanis, S; Bakry, N R

    2016-02-29

    Acute respiratory tract infections are leading causes of morbidity in poultry farms allover the world. Six pathogens; Escherichia coli, Mycoplasma gallisepticum, Staphylococcus aureus, Pasteurella multocida, Mannheimia haemolytica and Pseudomonas aeruginosa were involved in respiratory infections in poultry. Herein, conventional identification procedures and polymerase chain reaction (PCR) were applied for detection of the most common respiratory bacterial pathogens in clinical specimens of poultry obtained from 53 Egyptian farms with various respiratory problems and the results were compared statistically. The analyzed data demonstrated a significantly higher rate of detection of the most recovered microorganisms (Ppoultry farms were E. coli and Ps. aeruginosa (54.71% each), followed by M. haemolylica (35.85%) and M. gallisepticum (20.75%). In conclusion, PCR assay offered an effective alternative to traditional typing methods for the identification and simultaneous detection of the most clinically relevant respiratory pathogens in poultry.

  4. Bacterial iron-sulfur cluster sensors in mammalian pathogens

    Science.gov (United States)

    Miller, Halie K.; Auerbuch, Victoria

    2015-01-01

    Iron-sulfur clusters act as important cofactors for a number of transcriptional regulators in bacteria, including many mammalian pathogens. The sensitivity of iron-sulfur clusters to iron availability, oxygen tension, and reactive oxygen and nitrogen species enables bacteria to use such regulators to adapt their gene expression profiles rapidly in response to changing environmental conditions. In this review, we discuss how the [4Fe-4S] or [2Fe-2S] cluster-containing regulators FNR, Wbl, aconitase, IscR, NsrR, SoxR, and AirSR contribute to bacterial pathogenesis through control of both metabolism and classical virulence factors. In addition, we briefly review mammalian iron homeostasis as well as oxidative/nitrosative stress to provide context for understanding the function of bacterial iron-sulfur cluster sensors in different niches within the host. PMID:25738802

  5. Perspective: Adhesion Mediated Signal Transduction in Bacterial Pathogens

    Science.gov (United States)

    Moorthy, Sudha; Keklak, Julia; Klein, Eric A.

    2016-01-01

    During the infection process, pathogenic bacteria undergo large-scale transcriptional changes to promote virulence and increase intrahost survival. While much of this reprogramming occurs in response to changes in chemical environment, such as nutrient availability and pH, there is increasing evidence that adhesion to host-tissue can also trigger signal transduction pathways resulting in differential gene expression. Determining the molecular mechanisms of adhesion-mediated signaling requires disentangling the contributions of chemical and mechanical stimuli. Here we highlight recent work demonstrating that surface attachment drives a transcriptional response in bacterial pathogens, including uropathogenic Escherichia coli (E. coli), and discuss the complexity of experimental design when dissecting the specific role of adhesion-mediated signaling during infection. PMID:26901228

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

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    Robert K. Flamm

    2014-04-01

    Full Text Available A total of 2484 target bacterial pathogens were collected (one per patient episode from patients in 16 Latin American medical centers located in seven nations during 2011. Isolate identity was confirmed at a coordinating laboratory and susceptibility testing was performed for ceftaroline and comparator agents according to reference broth microdilution methods. A total of 30.0% of isolates were from respiratory tract, 29.4% from skin and skin structure, 21.4% from blood stream, 7.9% from urinary tract and 11.3% from other sites. Ceftaroline was active againstStaphylococcus aureus (42.8% MRSA with 83.6% of the isolates at 90.0% of the non-ESBL-phenotype. The spectrum of activity of ceftaroline against pathogens from Latin America indicates that it merits further study for its potential use in the Latin American region.

  7. Relationship between lactobacilli and opportunistic bacterial pathogens associated with vaginitis

    Science.gov (United States)

    Razzak, Mohammad Sabri A.; Al-Charrakh, Alaa H.; AL-Greitty, Bara Hamid

    2011-01-01

    Background: Vaginitis, is an infectious inflammation of the vaginal mucosa, which sometimes involves the vulva. The balance of the vaginal flora is maintained by the Lactobacilli and its protective and probiotic role in treating and preventing vaginal infection by producing antagonizing compounds which are regarded as safe for humans. Aim: The aim of this study was to evaluate the protective role of Lactobacilli against common bacterial opportunistic pathogens in vaginitis and study the effects of some antibiotics on Lactobacilli isolates. Materials and Methods: In this study (110) vaginal swabs were obtained from women suffering from vaginitis who admitted to Babylon Hospital of Maternity and Paediatrics in Babylon province, Iraq. The study involved the role of intrauterine device among married women with vaginitis and also involved isolation of opportunistic bacterial isolates among pregnant and non pregnant women. This study also involved studying probiotic role of Lactobacilli by production of some defense factors like hydrogen peroxide, bacteriocin, and lactic acid. Results: Results revealed that a total of 130 bacterial isolates were obtained. Intrauterine device was a predisposing factor for vaginitis. The most common opportunistic bacterial isolates were Staphylococcus aureus, Escherichia coli, Streptococcus agalactiae, and Klebsiella pneumoniae. All Lactobacilli were hydrogen peroxide producers while some isolates were bacteriocin producers that inhibited some of opportunistic pathogens (S. aureus, E. coli). Lactobacilli were sensitive to erythromycin while 93.3% of them were resistant to ciprofloxacin and (40%, 53.3%) of them were resistant to amoxicillin and gentamycin respectively. Results revealed that there was an inverse relationship between Lactobacilli presence and organisms causing vaginitis. This may be attributed to the production of defense factors by Lactobacilli. Conclusion: The types of antibiotics used to treat vaginitis must be very

  8. Relationship between lactobacilli and opportunistic bacterial pathogens associated with vaginitis.

    Science.gov (United States)

    Razzak, Mohammad Sabri A; Al-Charrakh, Alaa H; Al-Greitty, Bara Hamid

    2011-04-01

    Vaginitis, is an infectious inflammation of the vaginal mucosa, which sometimes involves the vulva. The balance of the vaginal flora is maintained by the Lactobacilli and its protective and probiotic role in treating and preventing vaginal infection by producing antagonizing compounds which are regarded as safe for humans. The aim of this study was to evaluate the protective role of Lactobacilli against common bacterial opportunistic pathogens in vaginitis and study the effects of some antibiotics on Lactobacilli isolates. In this study (110) vaginal swabs were obtained from women suffering from vaginitis who admitted to Babylon Hospital of Maternity and Paediatrics in Babylon province, Iraq. The study involved the role of intrauterine device among married women with vaginitis and also involved isolation of opportunistic bacterial isolates among pregnant and non pregnant women. This study also involved studying probiotic role of Lactobacilli by production of some defense factors like hydrogen peroxide, bacteriocin, and lactic acid. Results revealed that a total of 130 bacterial isolates were obtained. Intrauterine device was a predisposing factor for vaginitis. The most common opportunistic bacterial isolates were Staphylococcus aureus, Escherichia coli, Streptococcus agalactiae, and Klebsiella pneumoniae. All Lactobacilli were hydrogen peroxide producers while some isolates were bacteriocin producers that inhibited some of opportunistic pathogens (S. aureus, E. coli). Lactobacilli were sensitive to erythromycin while 93.3% of them were resistant to ciprofloxacin and (40%, 53.3%) of them were resistant to amoxicillin and gentamycin respectively. Results revealed that there was an inverse relationship between Lactobacilli presence and organisms causing vaginitis. This may be attributed to the production of defense factors by Lactobacilli. The types of antibiotics used to treat vaginitis must be very selective in order not to kill the beneficial bacteria

  9. Antimicrobial Resistance in Bacterial Poultry Pathogens: A Review.

    Science.gov (United States)

    Nhung, Nguyen Thi; Chansiripornchai, Niwat; Carrique-Mas, Juan J

    2017-01-01

    monitor the evolution of AMR in poultry bacterial pathogens.

  10. Characterization of bacterial pathogens in rural and urban irrigation water.

    Science.gov (United States)

    Aijuka, Matthew; Charimba, George; Hugo, Celia J; Buys, Elna M

    2015-03-01

    The study aimed to compare the bacteriological quality of an urban and rural irrigation water source. Bacterial counts, characterization, identification and diversity of aerobic bacteria were determined. Escherichia coli isolated from both sites was subjected to antibiotic susceptibility testing, virulence gene (Stx1/Stx2 and eae) determination and (GTG)5 Rep-PCR fingerprinting. Low mean monthly counts for aerobic spore formers, anaerobic spore formers and Staphylococcus aureus were noted although occasional spikes were observed. The most prevalent bacterial species at both sites were Bacillus spp., E. coli and Enterobacter spp. In addition, E. coli and Bacillus spp. were most prevalent in winter and summer respectively. Resistance to at least one antibiotic was 84% (rural) and 83% (urban). Highest resistance at both sites was to cephalothin and ampicillin. Prevalence of E. coli possessing at least one virulence gene (Stx1/Stx2 and eae) was 15% (rural) and 42% (urban). All (rural) and 80% (urban) of E. coli possessing virulence genes showed antibiotic resistance. Complete genetic relatedness (100%) was shown by 47% of rural and 67% of urban E. coli isolates. Results from this study show that surface irrigation water sources regardless of geographical location and surrounding land-use practices can be reservoirs of similar bacterial pathogens.

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

    Science.gov (United States)

    Leonardi, William; Zilbermintz, Leeor; Cheng, Luisa W; Zozaya, Josue; Tran, Sharon H; Elliott, Jeffrey H; Polukhina, Kseniya; Manasherob, Robert; Li, Amy; Chi, Xiaoli; Gharaibeh, Dima; Kenny, Tara; Zamani, Rouzbeh; Soloveva, Veronica; Haddow, Andrew D; Nasar, Farooq; Bavari, Sina; Bassik, Michael C; Cohen, Stanley N; Levitin, Anastasia; Martchenko, Mikhail

    2016-09-30

    Diverse pathogenic agents often utilize overlapping host networks, and hub proteins within these networks represent attractive targets for broad-spectrum drugs. Using bacterial toxins, we describe a new approach for discovering broad-spectrum therapies capable of inhibiting host proteins that mediate multiple pathogenic pathways. This approach can be widely used, as it combines genetic-based target identification with cell survival-based and protein function-based multiplex drug screens, and concurrently discovers therapeutic compounds and their protein targets. Using B-lymphoblastoid cells derived from the HapMap Project cohort of persons of African, European, and Asian ancestry we identified host caspases as hub proteins that mediate the lethality of multiple pathogenic agents. We discovered that an approved drug, Bithionol, inhibits host caspases and also reduces the detrimental effects of anthrax lethal toxin, diphtheria toxin, cholera toxin, Pseudomonas aeruginosa exotoxin A, Botulinum neurotoxin, ricin, and Zika virus. Our study reveals the practicality of identifying host proteins that mediate multiple disease pathways and discovering broad-spectrum therapies that target these hub proteins.

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

    Science.gov (United States)

    Leonardi, William; Zilbermintz, Leeor; Cheng, Luisa W.; Zozaya, Josue; Tran, Sharon H.; Elliott, Jeffrey H.; Polukhina, Kseniya; Manasherob, Robert; Li, Amy; Chi, Xiaoli; Gharaibeh, Dima; Kenny, Tara; Zamani, Rouzbeh; Soloveva, Veronica; Haddow, Andrew D.; Nasar, Farooq; Bavari, Sina; Bassik, Michael C.; Cohen, Stanley N.; Levitin, Anastasia; Martchenko, Mikhail

    2016-01-01

    Diverse pathogenic agents often utilize overlapping host networks, and hub proteins within these networks represent attractive targets for broad-spectrum drugs. Using bacterial toxins, we describe a new approach for discovering broad-spectrum therapies capable of inhibiting host proteins that mediate multiple pathogenic pathways. This approach can be widely used, as it combines genetic-based target identification with cell survival-based and protein function-based multiplex drug screens, and concurrently discovers therapeutic compounds and their protein targets. Using B-lymphoblastoid cells derived from the HapMap Project cohort of persons of African, European, and Asian ancestry we identified host caspases as hub proteins that mediate the lethality of multiple pathogenic agents. We discovered that an approved drug, Bithionol, inhibits host caspases and also reduces the detrimental effects of anthrax lethal toxin, diphtheria toxin, cholera toxin, Pseudomonas aeruginosa exotoxin A, Botulinum neurotoxin, ricin, and Zika virus. Our study reveals the practicality of identifying host proteins that mediate multiple disease pathways and discovering broad-spectrum therapies that target these hub proteins. PMID:27686742

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

    Directory of Open Access Journals (Sweden)

    Antariksh Deep

    2011-01-01

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

  14. Rapid pathogen detection with bacterial-assembled magnetic mesoporous silica.

    Science.gov (United States)

    Lee, Soo Youn; Lee, Jiho; Lee, Hye Sun; Chang, Jeong Ho

    2014-03-15

    We report rapid and accurate pathogen detection by coupling with high efficiency magnetic separation of pathogen by Ni(2+)-heterogeneous magnetic mesoporous silica (Ni-HMMS) and real time-polymerase chain reaction (RT-PCR) technique. Ni-HMMS was developed with a significant incorporation of Fe particles within the silica mesopores by programmed thermal hydrogen reaction and functionalized with Ni(2+) ion on the surface by the wet impregnation process. High abundant Ni(2+) ions on the Ni-HMMS surface were able to assemble with cell wall component protein NikA (nickel-binding membrane protein), which contains several pathogenic bacteria including Escherichia coli O157:H7. NikA protein expression experiment showed the outstanding separation rate of the nikA gene-overexpressed E. coli (pSY-Nik) when comparing with wild-type E. coli (44.5 ± 13%) or not over-expressed E. coli (pSY-Nik) (53.2 ± 2.7%). Moreover, Ni-HMMS showed lower obstacle effect by large reaction volume (10 mL) than spherical core/shell-type silica magnetic nanoparticles functionalized with Ni(2+) (ca. 40 nm-diameters). Finally, the Ni-HMMS was successfully assessed to separate pathogenic E. coli O157:H7 and applied to direct and rapid RT-PCR to quantitative detection at ultralow concentration (1 Log10 cfu mL(-1)) in the real samples (milk and Staphylococcus aureus culture broth) without bacterial amplification and DNA extraction step.

  15. Prevalence of bacterial pathogens causing ocular infections in South India

    Directory of Open Access Journals (Sweden)

    Ramesh S

    2010-04-01

    Full Text Available Background / Aims: The eye may be infected from external sources or through intra-ocular invasion of micro-organisms carried by the blood stream. This study was undertaken to isolate and identify the specific bacterial pathogens causing ocular infections and to determine their in-vitro antibacterial susceptibilities to commonly used antibacterial agents. Materials and Methods: A retrospective analysis of all patients with clinically diagnosed bacterial ocular infections such as blepharitis, conjunctivitis, internal and external hordeolum, suppurative scleritis, canaliculitis, keratitis, dacryocystitis, preseptal cellulitis, endophthalmitis and panophthalmitis presenting between January 2005 and December 2005 was performed. Extra-ocular and intra-ocular specimens were collected and were subjected to direct microscopy and culture. Results: A total of 756 patients with bacterial ocular infections were analyzed, of which 462(61% eyes had adnexal bacterial infection, 217(28.7% had corneal infection, 6 (0.8% had scleral involvement and the remaining 71(9.39% eyes had infection of the intra-ocular tissues. The predominant bacterial species isolated was S. aureus (195 of 776; 25% followed by S. pneumoniae (169 of 776; 21.78% and coagulase negative staphylococci (142 of 776; 18.3%. The largest number of gram-positive isolates were susceptible to cefazolin (545 of 624; 87.34%, chloramphenicol (522 of 624; 83.65% and gatifloxacin (511 of 624; 81.89% and gram-negative isolates were to amikacin (127 of 136; 93.38%, gatifloxacin (125 of 136; 91.91% and ofloxacin (119 of 136; 87.5%, while aerobic actinomycetes were to amikacin (100%, gatifloxacin (14 of 16; 87.5%, chloramphenicol (14 of 16; 87.5% and ofloxacin (13 of 16; 81.25%. Conclusions: S. aureus frequently causes infections of eyelids and conjunctiva, S. pneumoniae of lacrimal apparatus and cornea and coagulase negative staphylococci causes intra-ocular infections. Of all routinely used antibacterials

  16. Occurrence of Potentially Pathogenic Bacterial-Endosymbionts in Acanthamoeba Spp.

    Directory of Open Access Journals (Sweden)

    Maryam Niyyati

    2015-06-01

    Full Text Available Acanthamoeba- bacteria interactions enable pathogenic bacteria to tolerate harsh conditions and lead to transmission to the susceptible host. The present study was aimed to address the presence of bacterial endosymbionts of Acanthamoeba isolated from recreational water sources of Tehran, Iran. To the best of our knowledge this is the first study regarding occurrence of bacteria in environmental Acanthamoeba spp. in Iran.A total of 75 samples of recreational water sources were collected. Samples were cultured on non- nutrient agar 1.5% plates. Positive Acanthamoeba spp. were axenically grown. DNA extraction and PCR reaction was performed using JDP1-2 primers. All positive samples of Acanthamoeba were examined for the presence of endosymbionts using staining and molecular methods. The PCR products were then sequenced in order to determine the genotypes of Acanthamoeba and bacteria genera.Out of 75 samples, 16 (21.3% plates were positive for Acanthamoeba according to the morphological criteria. Molecular analysis revealed that Acanthamoeba belonged to T4 and T5 genotypes. Five isolates (35.7% were positive for bacterial endosymbionts using staining method and PCR test. Sequencing of PCR products confirmed the presence of Pseudomonas aeruginosa and Agrobacterium tumefasiens.The presence of Acanthamoeba bearing pathogenic endosymbionts in water sources leads us to public health issues including improved sanitation and decontamination measures in recreational water sources in order to prevent amoebae-related infection. To the best of our knowledge this is the first report regarding the isolation of A. tumefasiens from Acanthamoeba in Iran and worldwide.

  17. Removal of pathogenic bacterial biofilms by combinations of oxidizing compounds.

    Science.gov (United States)

    Olmedo, Gabriela María; Grillo-Puertas, Mariana; Cerioni, Luciana; Rapisarda, Viviana Andrea; Volentini, Sabrina Inés

    2015-05-01

    Bacterial biofilms are commonly formed on medical devices and food processing surfaces. The antimicrobials used have limited efficacy against the biofilms; therefore, new strategies to prevent and remove these structures are needed. Here, the effectiveness of brief oxidative treatments, based on the combination of sodium hypochlorite (NaClO) and hydrogen peroxide (H2O2) in the presence of copper sulfate (CuSO4), were evaluated against bacterial laboratory strains and clinical isolates, both in planktonic and biofilm states. Simultaneous application of oxidants synergistically inactivated planktonic cells and prevented biofilm formation of laboratory Escherichia coli, Salmonella enterica serovar Typhimurium, Klebsiella pneumoniae, and Staphylococcus aureus strains, as well as clinical isolates of Salmonella enterica subsp. enterica, Klebsiella oxytoca, and uropathogenic E. coli. In addition, preformed biofilms of E. coli C, Salmonella Typhimurium, K. pneumoniae, and Salmonella enterica exposed to treatments were removed by applying 12 mg/L NaClO, 0.1 mmol/L CuSO4, and 350 mmol/L H2O2 for 5 min. Klebsiella oxytoca and Staphylococcus aureus required a 5-fold increase in NaClO concentration, and the E. coli clinical isolate remained unremovable unless treatments were applied on biofilms formed within 24 h instead of 48 h. The application of treatments that last a few minutes using oxidizing compounds at low concentrations represents an interesting disinfection strategy against pathogens associated with medical and industrial settings.

  18. The bacterial pathogen-ubiquitin interface: lessons learned from Shigella.

    Science.gov (United States)

    Tanner, Kaitlyn; Brzovic, Peter; Rohde, John R

    2015-01-01

    Shigella species are the aetiological agents of shigellosis, a severe diarrhoeal disease that is a significant cause of morbidity and mortality worldwide. Shigellosis causes massive colonic destruction, high fever and bloody diarrhoea. Shigella pathogenesis is tightly linked to the ability of the bacterium to invade and replicate intracellularly within the colonic epithelium. Shigella uses a type 3 secretion system to deliver its effector proteins into the cytosol of infected cells. Among the repertoire of Shigella effectors, many are known to target components of the actin cytoskeleton to promote bacterial entry. An emerging alternate theme for effector function is the targeting of the host ubiquitin system. Ubiquitination is a post-translational modification restricted to eukaryotes and is involved in many essential host processes. By virtue of sheer number of ubiquitin-modulating effector proteins, it is clear that Shigella has invested heavily into subversion of the ubiquitin system. Understanding these host-pathogen interactions will inform us about the strategies used by successful pathogens and may also provide avenues for novel antimicrobial strategies.

  19. Advances in genetic manipulation of obligate intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Paul eBeare

    2011-05-01

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

  20. Modulation of connexin signaling by bacterial pathogens and their toxins.

    Science.gov (United States)

    Ceelen, Liesbeth; Haesebrouck, Freddy; Vanhaecke, Tamara; Rogiers, Vera; Vinken, Mathieu

    2011-09-01

    Inherent to their pivotal tasks in the maintenance of cellular homeostasis, gap junctions, connexin hemichannels, and pannexin hemichannels are frequently involved in the dysregulation of this critical balance. The present paper specifically focuses on their roles in bacterial infection and disease. In particular, the reported biological outcome of clinically important bacteria including Escherichia coli, Shigella flexneri, Yersinia enterocolitica, Helicobacter pylori, Bordetella pertussis, Aggregatibacter actinomycetemcomitans, Pseudomonas aeruginosa, Citrobacter rodentium, Clostridium species, Streptococcus pneumoniae, and Staphylococcus aureus and their toxic products on connexin- and pannexin-related signaling in host cells is reviewed. Particular attention is paid to the underlying molecular mechanisms of these effects as well as to the actual biological relevance of these findings.

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

    OpenAIRE

    Eslami; Karimiravesh; Taheri; Azargashb

    2014-01-01

    Background Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. Objectives The purpose of this study was to investigate the inhibitory effect of Lactobacillus reuteri on pathogenic bacteria isolated from women with bacterial vaginosis. ...

  2. USGS/EPA collection protocol for bacterial pathogens in soil

    Science.gov (United States)

    Griffin, Dale W.; Shaefer, F.L.; Charlena Bowling,; Dino Mattorano,; Tonya Nichols,; Erin Silvestri,

    2014-01-01

    This Sample Collection Procedure (SCP) describes the activities and considerations for the collection of bacterial pathogens from representative surface soil samples (0-5 cm). This sampling depth can be reached without the use of a drill rig, direct-push technology, or other mechanized equipment. This procedure can be used in most soil types but is limited to sampling at or near the ground surface. This protocol has components for two different types of sampling applications: (1) typical sampling, when there is no suspicion of contamination (e.g., surveillance or background studies); and (2) in response to known or suspected accidental contamination (e.g., the presence of animal carcasses). This protocol does not cover sampling in response to a suspected bioterrorist or intentional release event. Surface material is removed to the required depth (0-5 cm) and clean trowel or 50 ml sample tube is used to collect the sample. Sample containers are sealed, bagged, and shipped to the laboratory for analysis. Associated documentation, including a Field Data Log and Chain-of-Custody are also included in this document.

  3. Bacterial biofilm formation, pathogenicity, diagnostics and control: An overview

    Directory of Open Access Journals (Sweden)

    Sawhney Rajesh

    2009-07-01

    Full Text Available Bacterial biofilms are complex, mono- or poly-microbialn communities adhering to biotic or abiotic surfaces. This adaptation has been implicated as a survival strategy. The formation of biofilms is mediated by mechanical, biochemical and genetical factors. The biofilms enhance the virulence of the pathogen and have their potential role in various infections, such as dental caries, cystic fibrosis, osteonecrosis, urinary tract infection and eye infections. A number of diagnostic techniques, viz., bright-field microscopy, epifluorescence microscopy, scanning electron microscopy, confocal laser scanning microscopy and amplicon length heterogeneity polymerase chain reaction, have been employed for detection of these communities. Researchers have worked on applications of catheter lock solutions, a fish protein coating, acid shock treatment, susceptibility to bacteriophages, etc., for biofilm control. However, we need to rearrange our strategies to have thorough insight and concentrate on priority basis to develop new accurate, precise and rapid diagnostic protocols for detection and evaluation of biofilm. Above all, the strict compliance to these techniques is required for accurate diagnosis and control.

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

    OpenAIRE

    Gita Eslami; Sudabeh Taheri; Eznollah Azargashb; raheleh karimiravesh

    2014-01-01

    Background: Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. The purpose of this study is to investigate the inhibitory effect of Lactobacillus rhamnosus on pathogenic bacteria isolated from women with bacterial vaginosis, respectively.Materials and Methods: 96 samples from women with bacterial vaginosis di...

  5. Pathogenicity testing of shellfish hatchery bacterial isolates on Pacific oyster Crassostrea gigas larvae.

    Science.gov (United States)

    Estes, Robyn M; Friedman, Carolyn S; Elston, Ralph A; Herwig, Russell P

    2004-03-10

    Bacterial diseases are a major cause of larval mortality in shellfish hatcheries. Even with proper sanitation measures, bacterial pathogens cannot be eliminated in all cases. The pathogenicity of bacteria isolated from Pacific Northwest shellfish hatcheries to Pacific oyster Crassostrea gigas larvae was investigated. We found 3 highly pathogenic strains and 1 mildly pathogenic strain among 33 isolates tested. These strains appear to be members of the genus Vibrio. Although there have been many studies of bivalve bacterial pathogens, a standard method to assess bacterial pathogenicity in bivalve larvae is needed. Thus, we developed 2 methods using either 15 ml conical tubes or tissue culture plates that were employed for rapidly screening bacterial strains for pathogenicity to Pacific oyster larvae. The tissue culture plates worked well for screening both mildly pathogenic strains and LD50 (lethal dose) assays. This method allowed for non-intrusive and non-destructive observation of the oyster larvae with a dissecting microscope. The LD50 for the 3 highly pathogenic strains ranged between 1.6 and 3.6 x 10(4) colony forming units (CFU) ml(-1) after 24 h and between 3.2 x 102 and 1.9 x 10(3) CFU ml(-1) after 48 h.

  6. The Capricious Nature of Bacterial Pathogens: Phasevarions and Vaccine Development

    Directory of Open Access Journals (Sweden)

    Aimee Tan

    2016-12-01

    Full Text Available Infectious diseases are a leading cause of morbidity and mortality worldwide, and vaccines are one of the most successful and cost-effective tools for disease prevention. One of the key considerations for rational vaccine development is the selection of appropriate antigens. Antigens must induce a protective immune response, and this response should be directed to stably expressed antigens so the target microbe can always be recognized by the immune system. Antigens with variable expression, due to environmental signals or phase variation (i.e., high frequency, random switching of expression, are not ideal vaccine candidates because variable expression could lead to immune evasion. Phase variation is often mediated by the presence of highly mutagenic simple tandem DNA repeats, and genes containing such sequences can be easily identified, and their use discounted as vaccine antigens reconsidered. Recent research has identified phase variably expressed DNA methyltransferases that act as global epigenetic regulators. These phase variable regulons, known as phasevarions, are associated with altered virulence phenotypes and/or expression of vaccine candidates. As such, genes encoding candidate vaccine antigens that have no obvious mechanism of phase variation may be subject to indirect, epigenetic control as part of a phasevarion. Bioinformatic and experimental studies are required to elucidate the distribution and mechanism of action of these DNA methyltransferases, and most importantly, whether they mediate epigenetic regulation of potential and current vaccine candidates. This process is essential to define the stably expressed antigen target profile of bacterial pathogens and thereby facilitate efficient, rational selection of vaccine antigens.

  7. Parasites can enhance infections of fish with bacterial pathogens

    Science.gov (United States)

    In aquaculture systems, fish are commonly infected by multiple pathogens, including parasites. Parasite Ichthyophthirius multifiliis (Ich) and bacterium Edwardsiella ictaluri are two common pathogens of cultured channel catfish. The objectives were to 1) evaluate the susceptibility of Ich parasitize...

  8. The bacterial microbiome of dermacentor andersoni ticks influences pathogen susceptibility

    Science.gov (United States)

    Ticks are of medical and veterinary importance due to their ability to transmit pathogens to humans and animals. The Rocky Mountain wood tick, Dermacentor andersoni, is a vector of a number of pathogens, including Anaplasma marginale, which is the most widespread tick-borne pathogen of livestock. Al...

  9. Potentially pathogenic Escherichia coli can form a biofilm under conditions relevant to the food production chain.

    Science.gov (United States)

    Nesse, Live L; Sekse, Camilla; Berg, Kristin; Johannesen, Karianne C S; Solheim, Heidi; Vestby, Lene K; Urdahl, Anne Margrete

    2014-04-01

    The biofilm-producing abilities of potentially human-pathogenic serotypes of Escherichia coli from the ovine reservoir were studied at different temperatures and on different surfaces. A possible influence of the hydrophobicity of the bacterial cells, as well as the presence of two virulence factors, the Shiga toxin-encoding (Stx) bacteriophage and the eae gene, was also studied. A total of 99 E. coli isolates of serotypes O26:H11, O103:H2, and O103:H25 isolated from sheep feces were included. The results show that isolates of all three E. coli serotypes investigated can produce biofilm on stainless steel, glass, and polystyrene at 12, 20, and 37°C. There was a good general correlation between the results obtained on the different surfaces. E. coli O103:H2 isolates produced much more biofilm than those of the other two serotypes at all three temperatures. In addition, isolates of serotype O26:H11 produced more biofilm than those of O103:H25 at 37°C. The hydrophobicity of the isolates varied between serotypes and was also influenced by temperature. The results strongly indicated that hydrophobicity influenced the attachment of the bacteria rather than their ability to form biofilm once attached. Isolates with the eae gene produced less biofilm at 37°C than isolates without this gene. The presence of a Stx bacteriophage did not influence biofilm production. In conclusion, our results show that potentially human-pathogenic E. coli from the ovine reservoir can form biofilm on various surfaces and at several temperatures relevant for food production and handling.

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

    Directory of Open Access Journals (Sweden)

    Ville-Petri Friman

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

  11. Molecular detection of bacterial pathogens using microparticle enhanced double-stranded DNA probes.

    Science.gov (United States)

    Riahi, Reza; Mach, Kathleen E; Mohan, Ruchika; Liao, Joseph C; Wong, Pak Kin

    2011-08-15

    Rapid, specific, and sensitive detection of bacterial pathogens is essential toward clinical management of infectious diseases. Traditional approaches for pathogen detection, however, often require time-intensive bacterial culture and amplification procedures. Herein, a microparticle enhanced double-stranded DNA probe is demonstrated for rapid species-specific detection of bacterial 16S rRNA. In this molecular assay, the binding of the target sequence to the fluorophore conjugated probe thermodynamically displaces the quencher probe and allows the fluorophore to fluoresce. By incorporation of streptavidin-coated microparticles to localize the biotinylated probes, the sensitivity of the assay can be improved by 3 orders of magnitude. The limit of detection of the assay is as few as eight bacteria without target amplification and is highly specific against other common pathogens. Its applicability toward clinical diagnostics is demonstrated by directly identifying bacterial pathogens in urine samples from patients with urinary tract infections.

  12. From Environment to Man: Genome Evolution and Adaptation of Human Opportunistic Bacterial Pathogens

    OpenAIRE

    Estelle Jumas-Bilak; Hélène Marchandin; Brigitte Lamy; Anne Lotthé; Fabien Aujoulat; Frédéric Roger; Alice Bourdier

    2012-01-01

    Environment is recognized as a huge reservoir for bacterial species and a source of human pathogens. Some environmental bacteria have an extraordinary range of activities that include promotion of plant growth or disease, breakdown of pollutants, production of original biomolecules, but also multidrug resistance and human pathogenicity. The versatility of bacterial life-style involves adaptation to various niches. Adaptation to both open environment and human specific niches is a major challe...

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

    Directory of Open Access Journals (Sweden)

    Eslami

    2014-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Dana Védy

    2009-04-01

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

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

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    is likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi...

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

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    is likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi...

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  18. Bacterial enteric pathogens and serum interleukin-6 levels in children with acute diarrhea

    Directory of Open Access Journals (Sweden)

    Herlina Herlina

    2016-07-01

    Conclusion Serum IL-6 levels are significantly more elevated in children with acute diarrhea and bacterial enteric pathogens. Therefore, serum IL-6 may be a useful marker for early identification of bacterial gastroenteritis in children aged 1-5 years. [Paediatr Indones. 2016;56:144-8.].

  19. [Influence of human gastrointestinal tract bacterial pathogens on host cell apoptosis].

    Science.gov (United States)

    Wronowska, Weronika; Godlewska, Renata; Jagusztyn-Krynicka, Elzbieta Katarzyna

    2005-01-01

    Several pathogenic bacteria are able to trigger apoptosis in the host cell, but the mechanisms by which it occurs differ, and the resulting pathology can take different courses. Induction and/or blockage of programmed cell death upon infection is a result of complex interaction of bacterial proteins with cellular proteins involved in signal transduction and apoptosis. In this review we focus on pro/anti-apoptotic activities exhibited by two enteric pathogens Salmonella enterica, Yersinia spp. and gastric pathogen Helicobacter pylori. We present current knowledge on how interaction between mammalian and bacterial cell relates to the molecular pathways of apoptosis, and what is the role of apoptosis in pathogenesis.

  20. Pattern and antimicrobial sensitivity of pathogens in acute bacterial ...

    African Journals Online (AJOL)

    The causative agents of acute bacterial meningitis vary from time to time and from place to place. ... period for prompt empirical treatment of this important cause of morbidity and ... using 3 diagnostic methods (Gram stain, culture and LPA).

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

    NARCIS (Netherlands)

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

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Derrick E Fouts

    2016-02-01

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

  3. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    Science.gov (United States)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

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

    KAUST Repository

    Weynberg, Karen D.

    2015-12-08

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

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

    Science.gov (United States)

    Weynberg, Karen D.; Voolstra, Christian R.; Neave, Matthew J.; Buerger, Patrick; van Oppen, Madeleine J. H.

    2015-01-01

    Disease is an increasing threat to reef-building corals. One of the few identified pathogens of coral disease is the bacterium Vibrio coralliilyticus. In Vibrio cholerae, infection by a bacterial virus (bacteriophage) results in the conversion of non-pathogenic strains to pathogenic strains and this can lead to cholera pandemics. Pathogenicity islands encoded in the V. cholerae genome play an important role in pathogenesis. Here we analyse five whole genome sequences of V. coralliilyticus to examine whether virulence is similarly driven by horizontally acquired elements. We demonstrate that bacteriophage genomes encoding toxin genes with homology to those found in pathogenic V. cholerae are integrated in V. coralliilyticus genomes. Virulence factors located on chromosomal pathogenicity islands also exist in some strains of V. coralliilyticus. The presence of these genetic signatures indicates virulence in V. coralliilyticus is driven by prophages and other horizontally acquired elements. Screening for pathogens of coral disease should target conserved regions in these elements. PMID:26644037

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Punsiri M Colonne

    2016-09-01

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

  8. Development and application of the active surveillance of pathogens microarray to monitor bacterial gene flux

    Directory of Open Access Journals (Sweden)

    Hinds Jason

    2008-10-01

    Full Text Available Abstract Background Human and animal health is constantly under threat by emerging pathogens that have recently acquired genetic determinants that enhance their survival, transmissibility and virulence. We describe the construction and development of an Active Surveillance of Pathogens (ASP oligonucleotide microarray, designed to 'actively survey' the genome of a given bacterial pathogen for virulence-associated genes. Results The microarray consists of 4958 reporters from 151 bacterial species and include genes for the identification of individual bacterial species as well as mobile genetic elements (transposons, plasmid and phage, virulence genes and antibiotic resistance genes. The ASP microarray was validated with nineteen bacterial pathogens species, including Francisella tularensis, Clostridium difficile, Staphylococcus aureus, Enterococcus faecium and Stenotrophomonas maltophilia. The ASP microarray identified these bacteria, and provided information on potential antibiotic resistance (eg sufamethoxazole resistance and sulfonamide resistance and virulence determinants including genes likely to be acquired by horizontal gene transfer (e.g. an alpha-haemolysin. Conclusion The ASP microarray has potential in the clinic as a diagnostic tool, as a research tool for both known and emerging pathogens, and as an early warning system for pathogenic bacteria that have been recently modified either naturally or deliberately.

  9. Bacterial Genome Engineering and Synthetic Biology: Combating Pathogens

    Science.gov (United States)

    2016-11-04

    AHL: N-acyl-L-homoserine lactone; CAI-1: Cholerae autoinducer-1; CDC: Centers for Disease Control and Prevention ; CRISPR: clustered regularly...Organization (WHO) and Centers for Disease Control and Prevention (CDC), there is an unprecedented increase in the occurrence of MDR infections...SB has enormous potential to develop biomedical therapies to prevent and treat diseases caused by bacterial infections. List of Abbreviations

  10. Bioinformatics analysis of bacterial pathogens from East African camels

    OpenAIRE

    Zubair, Saima

    2015-01-01

    The camel is the most valuable livestock species in arid and semi-arid regions in the Greater Horn of Africa. Streptococcus agalactiae and Staphylococcus aureus are important pathogens for a wide range of hosts including camels, cattle and humans. Streptococcus agalactiae has been reported to cause infections of the skin, the respiratory tract, the mammary gland and the vaginal tract in camels. Staphylococcus aureus has been isolated from the nasal cavity, wound infections and mastitis from c...

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

    DEFF Research Database (Denmark)

    Dalsgaard, Inger; Madsen, Lone

    2000-01-01

    During a 2-year period, bacterial fish pathogens were monitored on five rainbow trout, Oncorhynchus mykirs (Walbaum), freshwater farms in Denmark. A total of 1206 fish were examined and 361 bacterial isolates were identified phenotypically. Enteric redmouth disease, furunculosis and rainbow trout....... psychrophilum isolates showed resistance to oxolinic acid and oxytetracycline. No antibiotic resistant isolates were found among Y. ruckeri and A. salmonicida.......During a 2-year period, bacterial fish pathogens were monitored on five rainbow trout, Oncorhynchus mykirs (Walbaum), freshwater farms in Denmark. A total of 1206 fish were examined and 361 bacterial isolates were identified phenotypically. Enteric redmouth disease, furunculosis and rainbow trout...... of fry and larger fish. All isolates of F. psychrophilum showed proteolytic activities; however, a few isolates, belonging to serotype Fp(T) did not degrade elastin and were not associated with mortality. Increasing resistance problems to oxytetracycline were demonstrated. More than half of the F...

  12. Investigation of Anti-bacterial Activity against Food-borne Pathogens among Korean Domestic Algae

    Directory of Open Access Journals (Sweden)

    Ki-hyo Jang

    2015-03-01

    Full Text Available The aim of this study is to explore algal species with anti-bacterial activity against six food-borne pathogens. Among 51 marine algae, Laurencia okamurae Yamada and Dictyopteris undulata Holmes was elucidated to have a potent anti-bacterial activity against food-borne pathogens. Laurencia okamurae Yamada showed the clear zone around agar well on B. cereus, S. aureusand L. monocytogenes-spreading agar plate. Dictyopteris undulata Holmes had the anti-bacterial activity against S. chorelaesuis, B. cereus, S. aureus and L. monocytogenes on bacterial spreading agar plates. Antibacterial activity of L. okamurae Yamada and D. undulata Holmes had specifically susceptibility for B. cereus, S. aureus and L. monocytogenes and were superior to streptomycin, the authentic antibiotics. It is anticipated that new food preservatives can be explored and developed on the basis of this study.

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

    Directory of Open Access Journals (Sweden)

    Gita Eslami

    2014-06-01

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

  14. Pulmonary bacterial pathogens in cystic fibrosis patients and antibiotic therapy: a tool for the health workers

    OpenAIRE

    Coutinho, Henrique Douglas M.; Falcão-Silva,Vivyanne S.; Gonçalves, Gregório Fernandes

    2008-01-01

    Cystic fibrosis is the most common and best known genetic disease involving a defect in transepithelial Cl- transport by mutations in the CF gene on chromosome 7, which codes for the cystic fibrosis transmembrane conductance regulator protein (CFTR). The most serious symptoms are observed in the lungs, augmenting the risk of bacterial infection. The objective of this review was to describe the bacterial pathogens colonizing patients with cystic fibrosis. A systematic search was conducted usin...

  15. Daily variations in pathogenic bacterial populations in a monsoon influenced tropical environment

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.; Naik, S.D.; Gaonkar, C.C.

    , C.A., 2010.Comparison of the pathogenic potentials of environmental and clinical Vibrio parahaemolyticus strains indicates a role for temperature regulation of virulence. Appl.Environ.Microbiol. 76, 7459–7465 Moss, J.A., Nocker, A., Lepo, J... and the characteristics of the water body change. Bacterial populations, an important component of the microbial loop, influence food web dynamics and ecosystem functioning. The response of the bacterial population to the changing environment is rapid...

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

    Directory of Open Access Journals (Sweden)

    Matthew D Dyer

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

  17. Detection of Bacterial Wilt Pathogen and Isolation of Its Bacteriophage from Banana in Lumajang Area, Indonesia

    Directory of Open Access Journals (Sweden)

    Hardian Susilo Addy

    2016-01-01

    Full Text Available Bacterial wilt disease on banana is an important disease in Lumajang District and causes severe yield loss. Utilizing bacteriophage as natural enemy of pathogenic bacteria has been widely known as one of the control strategies. This research was aimed at determining the causing agent of bacterial wilt on banana isolated from Lumajang area, to obtain wide-host range bacteriophages against bacterial wilt pathogen and to know the basic characteristic of bacteriophages, particularly its nucleic acid type. Causative agent of bacterial wilt was isolated from symptomatic banana trees from seven districts in Lumajang area on determinative CPG plates followed by rapid detection by PCR technique using specific pair-primer. Bacteriophages were also isolated from soil of infected banana crop in Sukodono District. Morphological observation showed that all bacterial isolates have similar characteristic as common bacterial wilt pathogen, Ralstonia solanacearum. In addition, detection of FliC region in all isolates confirmed that all isolates were R. solanacearum according to the presence of 400 bp of FliC DNA fragment. Moreover, two bacteriophages were obtained from this experiment (ϕRSSKD1 and ϕRSSKD2, which were able to infect all nine R. solanacearum isolates. Nucleic acid analysis showed that the nucleic acid of bacteriophages was DNA (deoxyribonucleic acid.

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

    Science.gov (United States)

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

  19. Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part I: Overview, vaccines for enteric viruses and Vibrio cholerae.

    Science.gov (United States)

    O'Ryan, Miguel; Vidal, Roberto; del Canto, Felipe; Salazar, Juan Carlos; Montero, David

    2015-01-01

    Efforts to develop vaccines for prevention of acute diarrhea have been going on for more than 40 y with partial success. The myriad of pathogens, more than 20, that have been identified as a cause of acute diarrhea throughout the years pose a significant challenge for selecting and further developing the most relevant vaccine candidates. Based on pathogen distribution as identified in epidemiological studies performed mostly in low-resource countries, rotavirus, Cryptosporidium, Shigella, diarrheogenic E. coli and V. cholerae are predominant, and thus the main targets for vaccine development and implementation. Vaccination against norovirus is most relevant in middle/high-income countries and possibly in resource-deprived countries, pending a more precise characterization of disease impact. Only a few licensed vaccines are currently available, of which rotavirus vaccines have been the most outstanding in demonstrating a significant impact in a short time period. This is a comprehensive review, divided into 2 articles, of nearly 50 vaccine candidates against the most relevant viral and bacterial pathogens that cause acute gastroenteritis. In order to facilitate reading, sections for each pathogen are organized as follows: i) a discussion of the main epidemiological and pathogenic features; and ii) a discussion of vaccines based on their stage of development, moving from current licensed vaccines to vaccines in advanced stage of development (in phase IIb or III trials) to vaccines in early stages of clinical development (in phase I/II) or preclinical development in animal models. In this first article we discuss rotavirus, norovirus and Vibrio cholerae. In the following article we will discuss Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic), and Campylobacter jejuni.

  20. Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Zebenay Gezahegn

    2015-02-01

    Full Text Available Objective: To isolate and characterize the food associated bacterial strains, and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents (acetone, chloroform, methanol and petroleum ether leaf extracts of Thevetia peruviana (T. peruviana against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant. Methods: The food associated bacterial strains were isolated from students' lunch boxes in Tesfa Tewahido Primary School. The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods, respectively and phytochemical constituents were also detected in various solvent leaf extracts of T. peruviana. Results: The result showed that all the tested solvent leaf extracts of T. peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm. Amongst the tested food borne bacterial pathogens, Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T. peruviana while, methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains. Minimum inhibitory concentration of various solvent leaf extracts of T. peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains. The phytochemical constituents screening on the leaf extracts of T. peruviana showed the presence of alkaloids, cardiac glycosides, flavonoids, polyphenols, saponins and tannins. Conclusions: The present study suggests that T. peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.

  1. Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Zebenay Gezahegn; Mohd Sayeed Akhtar; Delelegn Woyessa; Yinebeb Tariku

    2015-01-01

    Objective:To isolate and characterize the food associated bacterial strains, and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents (acetone, chloroform, methanol and petroleum ether) leaf extracts of Thevetia peruviana (T. peruviana) against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant. Methods:The food associated bacterial strains were isolated from students' lunch boxes in Tesfa Tewahido Primary School. The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods, respectively and phytochemical constituents were also detected in various solvent leaf extracts of T. peruviana. Results:The result showed that all the tested solvent leaf extracts of T. peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm. Amongst the tested food borne bacterial pathogens, Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T. peruviana while, methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains. Minimum inhibitory concentration of various solvent leaf extracts of T. peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains. The phytochemical constituents screening on the leaf extracts of T. peruviana showed the presence of alkaloids, cardiac glycosides, flavonoids, polyphenols, saponins and tannins. Conclusions:The present study suggests that T. peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

    Luo, Gang; Angelidaki, Irini

    2014-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Soveri T

    2004-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Hongxia eGuan

    2016-03-01

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

  6. Intracellular Bacterial Pathogen Therapeutic Target Product Profile Guidelines

    Science.gov (United States)

    2009-02-24

    to meetthe warfighter requirements documented by the Joint Requirements Office (JRO) in the relevant rCD. Teratogenicity Category B Category D The...population indicated in the threshold value. The objectives and thresholds for teratogenicity are derived from the ratings from post- exposure of medications...provides teratogenicity ratings for all licensed medications. Category A refers to: • Adequate and well-controlled studies have failed to demonstrate

  7. Fungal-bacterial interactions and their relevance to oral health: linking the clinic and the bench

    Directory of Open Access Journals (Sweden)

    Patricia I Diaz

    2014-07-01

    Full Text Available High throughput sequencing has accelerated knowledge on the oral microbiome. While the bacterial component of oral communities has been extensively characterized, the role of the fungal microbiota in the oral cavity is largely unknown. Interactions among fungi and bacteria are likely to influence oral health as exemplified by the synergistic relationship between Candida albicans and oral streptococci. In this perspective, we discuss the current state of the field of fungal-bacterial interactions in the context of the oral cavity. We highlight the need to conduct longitudinal clinical studies to simultaneously characterize the bacterial and fungal components of the human oral microbiome in health and during disease progression. Such studies need to be coupled with investigations using disease-relevant models to mechanistically test the associations observed in humans and eventually identify fungal-bacterial interactions that could serve as preventive or therapeutic targets for oral diseases.

  8. Fungal-bacterial interactions and their relevance to oral health: linking the clinic and the bench.

    Science.gov (United States)

    Diaz, Patricia I; Strausbaugh, Linda D; Dongari-Bagtzoglou, Anna

    2014-01-01

    High throughput sequencing has accelerated knowledge on the oral microbiome. While the bacterial component of oral communities has been extensively characterized, the role of the fungal microbiota in the oral cavity is largely unknown. Interactions among fungi and bacteria are likely to influence oral health as exemplified by the synergistic relationship between Candida albicans and oral streptococci. In this perspective, we discuss the current state of the field of fungal-bacterial interactions in the context of the oral cavity. We highlight the need to conduct longitudinal clinical studies to simultaneously characterize the bacterial and fungal components of the human oral microbiome in health and during disease progression. Such studies need to be coupled with investigations using disease-relevant models to mechanistically test the associations observed in humans and eventually identify fungal-bacterial interactions that could serve as preventive or therapeutic targets for oral diseases.

  9. Large scale comparison of innate responses to viral and bacterial pathogens in mouse and macaque.

    Directory of Open Access Journals (Sweden)

    Guy Zinman

    Full Text Available Viral and bacterial infections of the lower respiratory tract are major causes of morbidity and mortality worldwide. Alveolar macrophages line the alveolar spaces and are the first cells of the immune system to respond to invading pathogens. To determine the similarities and differences between the responses of mice and macaques to invading pathogens we profiled alveolar macrophages from these species following infection with two viral (PR8 and Fuj/02 influenza A and two bacterial (Mycobacterium tuberculosis and Francisella tularensis Schu S4 pathogens. Cells were collected at 6 time points following each infection and expression profiles were compared across and between species. Our analyses identified a core set of genes, activated in both species and across all pathogens that were predominantly part of the interferon response pathway. In addition, we identified similarities across species in the way innate immune cells respond to lethal versus non-lethal pathogens. On the other hand we also found several species and pathogen specific response patterns. These results provide new insights into mechanisms by which the innate immune system responds to, and interacts with, invading pathogens.

  10. Importance of soil amendments: survival of bacterial pathogens in manure and compost used as organic fertizliers

    Science.gov (United States)

    Biological soil amendments (BSA’s) like manure and compost are frequently used as organic fertilizers to soils to improve its physical and chemical properties. However, BSAs have been known to be a reservoir for enteric bacterial pathogens like enterohemorrhagic E. coli, Salmonella spp, and Listeri...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2012-11-01

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

  16. Complete genome sequence of Japanese erwinia strain ejp617, a bacterial shoot blight pathogen of pear.

    Science.gov (United States)

    Park, Duck Hwan; Thapa, Shree Prasad; Choi, Beom-Soon; Kim, Won-Sik; Hur, Jang Hyun; Cho, Jun Mo; Lim, Jong-Sung; Choi, Ik-Young; Lim, Chun Keun

    2011-01-01

    The Japanese Erwinia strain Ejp617 is a plant pathogen that causes bacterial shoot blight of pear in Japan. Here, we report the complete genome sequence of strain Ejp617 isolated from Nashi pears in Japan to provide further valuable insight among related Erwinia species.

  17. Minimum Inhibitory Concentration Analysis of Nerium oleander against Bacterial Pathogens

    Institute of Scientific and Technical Information of China (English)

    M Abu Hena Mostofa Jamal; Shahedur Rahman; Md Azizul Islam; Md Rezaul Karim; Md Samsul Alam; Md Ziaur Rahman

    2012-01-01

    Objective: In this present study, it is tried to find out the antimicrobial effect and Minimum Inhibitory Concentration (MIC) of Nerium oleander against Bacillus subtilis (IFO 3026), Sarcina lutea (IFO 3232), Escherichia coli (IFO 3007) and Klebsiella Pneumoniae (ATTC 10031). Methods:Powered leaves were prepared and used for extraction with various solvents, viz, the petroleum ether, and chloroform extract of the oleander. All the solvent extracts were evaporated to dryness. Using the disc diffusion method, the bacterial growth were inhibited, Results: Among the solvent extracts tested, petroleum ether extract inhibited the growth of all the tested bacteria having various degrees of inhibition zones. Highest inhibitory activity was observed against E. coli (1.9 cm) and minimum inhibitory concentration was observed 2μg/ml also against E. coli. Both results were observed in case of petroleum ether extract. Petroleum ether extract also showed inhibitory zones of 1.8 cm, 1.4 cm and 1.5cm against B. subtilis, S. lutea and K. pneumoniae. On the other hand chloroform extract was observed to have inhibition zones of 1.2 cm, 1.6 cm, 1.8 cm and 1.5 cm against B. subtilis, S. lutea, E. coli and K. pneumoniae respectively. Conclusions: The study demonstrated that the petroleum ether extract of N. oleander is potentially good source of antibacterial agents. Further evaluation is necessary to identify the specific bioactive compounds, their mode of action and their nontoxic nature in vivo condition.

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

    Science.gov (United States)

    Eason, Mia M; Fan, Xin

    2014-09-01

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

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

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    Boknam Jung

    2013-12-01

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

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

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    Taya L. Forde

    2016-11-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2014-04-01

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

  3. A window of opportunity to control the bacterial pathogen Pseudomonas aeruginosa combining antibiotics and phages.

    Science.gov (United States)

    Torres-Barceló, Clara; Arias-Sánchez, Flor I; Vasse, Marie; Ramsayer, Johan; Kaltz, Oliver; Hochberg, Michael E

    2014-01-01

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

  4. Human caspase-4 mediates noncanonical inflammasome activation against gram-negative bacterial pathogens

    Science.gov (United States)

    Casson, Cierra N.; Yu, Janet; Reyes, Valeria M.; Taschuk, Frances O.; Yadav, Anjana; Copenhaver, Alan M.; Nguyen, Hieu T.; Collman, Ronald G.; Shin, Sunny

    2015-01-01

    Inflammasomes are critical for host defense against bacterial pathogens. In murine macrophages infected by gram-negative bacteria, the canonical inflammasome activates caspase-1 to mediate pyroptotic cell death and release of IL-1 family cytokines. Additionally, a noncanonical inflammasome controlled by caspase-11 induces cell death and IL-1 release. However, humans do not encode caspase-11. Instead, humans encode two putative orthologs: caspase-4 and caspase-5. Whether either ortholog functions similar to caspase-11 is poorly defined. Therefore, we sought to define the inflammatory caspases in primary human macrophages that regulate inflammasome responses to gram-negative bacteria. We find that human macrophages activate inflammasomes specifically in response to diverse gram-negative bacterial pathogens that introduce bacterial products into the host cytosol using specialized secretion systems. In primary human macrophages, IL-1β secretion requires the caspase-1 inflammasome, whereas IL-1α release and cell death are caspase-1–independent. Instead, caspase-4 mediates IL-1α release and cell death. Our findings implicate human caspase-4 as a critical regulator of noncanonical inflammasome activation that initiates defense against bacterial pathogens in primary human macrophages. PMID:25964352

  5. Interspecies communication between pathogens and immune cells via bacterial membrane vesicles

    Directory of Open Access Journals (Sweden)

    Katerina S Jurkoshek

    2016-11-01

    Full Text Available The production of extracellular vesicles is a universal mechanism for intercellular communication that is conserved across kingdoms. Prokaryotes secrete 50–250 nm membrane vesicles (MVs in a manner that is regulated by environmental stress and is thought to promote survival. Since many types of host-derived stress are encountered during infection, this implies an important role for MV secretion in bacterial pathogenesis. Accordingly, MVs produced by gram-positive and gram-negative pathogens contain toxins, virulence factors, and other molecules that promote survival in the host. However, recent studies have also shown that bacterial MVs are enriched for molecules that stimulate innate and adaptive immune responses. As an example, MVs may serve multiple, important roles in regulating the host response to Mycobacterium tuberculosis (Mtb, an intracellular pathogen that infects lung macrophages and resides within modified phagosomes. Previously, we demonstrated that Mtb secretes MVs during infection that may regulate infected and uninfected immune cells. Our present data demonstrates that Mtb MVs inhibit the functions of macrophages and T cells, but promote MHC-II antigen presentation by dendritic cells. We conclude that bacterial MVs serve dual and opposing roles in the activation of and defense against host immune responses to Mtb and other bacterial pathogens. We also propose that MV secretion is a central mechanism for interspecies communication between bacteria and host cells during infection.

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

    Directory of Open Access Journals (Sweden)

    Jose L Martinez

    2012-01-01

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

  7. In vitro anti- bacterial activity of leaves extracts of Albizia lebbeck Benth against some selected pathogens

    Institute of Scientific and Technical Information of China (English)

    Mohammed Nazneen Bobby; Edward Gnanaraj Wesely; MarimuthuAntonisamy Johnson

    2012-01-01

    Objective: To screen the anti-bacterial activity of Albizia lebbeck (A. lebbeck) Benth leaves extract against the selected bacterial pathogens viz., Bacillus subtilis (MTCC441), Escherichia coli (MTCC443), Klebsiella pneumonia (MTCC 109), Proteus vulgaris (MTCC742), Pseudomonas aeruginosa (MTCC741), Salmonella typhii (MTCC733) and Staphylococus aureus (MTCC96).Methods:The leaves extracts of A. lebbeck was tested against bacteria by the agar disc diffusion method. Results: Results of the present study indicated that different extracts of A. lebbeck showed inhibitory effects against the pathogens. The present study results demonstrated that methanolic extracts of A. lebbeck conferred the widest spectrum activities that inhibited the growth of all studied pathogens with the maximum zone of inhibition. The methanolic extracts ofA. lebbeck illustrated the highest zone of inhibition against the pathogens Bacillus subtilis (16 mm), Escherichia coli (22 mm), Klebsiella pneumonia (11 mm), Proteus vulgaris (18 mm), Pseudomonas aeruginosa (22 mm), Salmonella typhii (23 mm) and Staphylococus aureus (17 mm). The ethyl acetate extracts demonstrated maximum zone of inhibition against Escherichia coli (26 mm), Pseudomonas aeruginosa (22 mm) and Klebsiella pneumonia (16 mm). Conclusions: It is expected that this study would direct to the establishment of some active compounds that could be used to formulate new and more potent anti-bacterial drugs of natural origin.

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

    Directory of Open Access Journals (Sweden)

    Wen Shan Yew

    2013-08-01

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

  9. Intestinal microbiota in metabolic diseases: from bacterial community structure and functions to species of pathophysiological relevance.

    Science.gov (United States)

    Clavel, Thomas; Desmarchelier, Charles; Haller, Dirk; Gérard, Philippe; Rohn, Sascha; Lepage, Patricia; Daniel, Hannelore

    2014-07-01

    The trillions of bacterial cells that colonize the mammalian digestive tract influence both host physiology and the fate of dietary compounds. Gnotobionts and fecal transplantation have been instrumental in revealing the causal role of intestinal bacteria in energy homeostasis and metabolic dysfunctions such as type-2 diabetes. However, the exact contribution of gut bacterial metabolism to host energy balance is still unclear and knowledge about underlying molecular mechanisms is scant. We have previously characterized cecal bacterial community functions and host responses in diet-induced obese mice using omics approaches. Based on these studies, we here discuss issues on the relevance of mouse models, give evidence that the metabolism of cholesterol-derived compounds by gut bacteria is of particular importance in the context of metabolic disorders and that dominant species of the family Coriobacteriaceae are good models to study these functions.

  10. Molecular epidemiology of mastitis pathogens of dairy cattle and comparative relevance to humans.

    Science.gov (United States)

    Zadoks, Ruth N; Middleton, John R; McDougall, Scott; Katholm, Jorgen; Schukken, Ynte H

    2011-12-01

    Mastitis, inflammation of the mammary gland, can be caused by a wide range of organisms, including gram-negative and gram-positive bacteria, mycoplasmas and algae. Many microbial species that are common causes of bovine mastitis, such as Escherichia coli, Klebsiella pneumoniae, Streptococcus agalactiae and Staphylococcus aureus also occur as commensals or pathogens of humans whereas other causative species, such as Streptococcus uberis, Streptococcus dysgalactiae subsp. dysgalactiae or Staphylococcus chromogenes, are almost exclusively found in animals. A wide range of molecular typing methods have been used in the past two decades to investigate the epidemiology of bovine mastitis at the subspecies level. These include comparative typing methods that are based on electrophoretic banding patterns, library typing methods that are based on the sequence of selected genes, virulence gene arrays and whole genome sequencing projects. The strain distribution of mastitis pathogens has been investigated within individual animals and across animals, herds, countries and host species, with consideration of the mammary gland, other animal or human body sites, and environmental sources. Molecular epidemiological studies have contributed considerably to our understanding of sources, transmission routes, and prognosis for many bovine mastitis pathogens and to our understanding of mechanisms of host-adaptation and disease causation. In this review, we summarize knowledge gleaned from two decades of molecular epidemiological studies of mastitis pathogens in dairy cattle and discuss aspects of comparative relevance to human medicine.

  11. From Environment to Man: Genome Evolution and Adaptation of Human Opportunistic Bacterial Pathogens

    Science.gov (United States)

    Aujoulat, Fabien; Roger, Frédéric; Bourdier, Alice; Lotthé, Anne; Lamy, Brigitte; Marchandin, Hélène; Jumas-Bilak, Estelle

    2012-01-01

    Environment is recognized as a huge reservoir for bacterial species and a source of human pathogens. Some environmental bacteria have an extraordinary range of activities that include promotion of plant growth or disease, breakdown of pollutants, production of original biomolecules, but also multidrug resistance and human pathogenicity. The versatility of bacterial life-style involves adaptation to various niches. Adaptation to both open environment and human specific niches is a major challenge that involves intermediate organisms allowing pre-adaptation to humans. The aim of this review is to analyze genomic features of environmental bacteria in order to explain their adaptation to human beings. The genera Pseudomonas, Aeromonas and Ochrobactrum provide valuable examples of opportunistic behavior associated to particular genomic structure and evolution. Particularly, we performed original genomic comparisons among aeromonads and between the strictly intracellular pathogens Brucella spp. and the mild opportunistic pathogens Ochrobactrum spp. We conclude that the adaptation to human could coincide with a speciation in action revealed by modifications in both genomic and population structures. This adaptation-driven speciation could be a major mechanism for the emergence of true pathogens besides the acquisition of specialized virulence factors. PMID:24704914

  12. Crystal structures of Cif from bacterial pathogens Photorhabdus luminescens and Burkholderia pseudomallei.

    Science.gov (United States)

    Crow, Allister; Race, Paul R; Jubelin, Grégory; Varela Chavez, Carolina; Escoubas, Jean-Michel; Oswald, Eric; Banfield, Mark J

    2009-01-01

    A pre-requisite for bacterial pathogenesis is the successful interaction of a pathogen with a host. One mechanism used by a broad range of Gram negative bacterial pathogens is to deliver effector proteins directly into host cells through a dedicated type III secretion system where they modulate host cell function. The cycle inhibiting factor (Cif) family of effector proteins, identified in a growing number of pathogens that harbour functional type III secretion systems and have a wide host range, arrest the eukaryotic cell cycle. Here, the crystal structures of Cifs from the insect pathogen/nematode symbiont Photorhabdus luminescens (a gamma-proteobacterium) and human pathogen Burkholderia pseudomallei (a beta-proteobacterium) are presented. Both of these proteins adopt an overall fold similar to the papain sub-family of cysteine proteases, as originally identified in the structure of a truncated form of Cif from Enteropathogenic E. coli (EPEC), despite sharing only limited sequence identity. The structure of an N-terminal region, referred to here as the 'tail-domain' (absent in the EPEC Cif structure), suggests a surface likely to be involved in host-cell substrate recognition. The conformation of the Cys-His-Gln catalytic triad is retained, and the essential cysteine is exposed to solvent and addressable by small molecule reagents. These structures and biochemical work contribute to the rapidly expanding literature on Cifs, and direct further studies to better understand the molecular details of the activity of these proteins.

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

    Directory of Open Access Journals (Sweden)

    Wan-Chen Tsai

    2012-10-01

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

  14. Crystal structures of Cif from bacterial pathogens Photorhabdus luminescens and Burkholderia pseudomallei.

    Directory of Open Access Journals (Sweden)

    Allister Crow

    Full Text Available A pre-requisite for bacterial pathogenesis is the successful interaction of a pathogen with a host. One mechanism used by a broad range of Gram negative bacterial pathogens is to deliver effector proteins directly into host cells through a dedicated type III secretion system where they modulate host cell function. The cycle inhibiting factor (Cif family of effector proteins, identified in a growing number of pathogens that harbour functional type III secretion systems and have a wide host range, arrest the eukaryotic cell cycle. Here, the crystal structures of Cifs from the insect pathogen/nematode symbiont Photorhabdus luminescens (a gamma-proteobacterium and human pathogen Burkholderia pseudomallei (a beta-proteobacterium are presented. Both of these proteins adopt an overall fold similar to the papain sub-family of cysteine proteases, as originally identified in the structure of a truncated form of Cif from Enteropathogenic E. coli (EPEC, despite sharing only limited sequence identity. The structure of an N-terminal region, referred to here as the 'tail-domain' (absent in the EPEC Cif structure, suggests a surface likely to be involved in host-cell substrate recognition. The conformation of the Cys-His-Gln catalytic triad is retained, and the essential cysteine is exposed to solvent and addressable by small molecule reagents. These structures and biochemical work contribute to the rapidly expanding literature on Cifs, and direct further studies to better understand the molecular details of the activity of these proteins.

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

    DEFF Research Database (Denmark)

    Dalsgaard, Inger; Madsen, Lone

    2000-01-01

    During a 2-year period, bacterial fish pathogens were monitored on five rainbow trout, Oncorhynchus mykirs (Walbaum), freshwater farms in Denmark. A total of 1206 fish were examined and 361 bacterial isolates were identified phenotypically. Enteric redmouth disease, furunculosis and rainbow trout....... psychrophilum isolates showed resistance to oxolinic acid and oxytetracycline. No antibiotic resistant isolates were found among Y. ruckeri and A. salmonicida....... fry syndrome/coldwater disease were recorded. Infections caused by Flavobacterium psychrophilum occurred most frequently, but only one outbreak of enteric redmouth disease caused by Yersinia ruckeri serotype O1 and one of furunculosis caused by Aeromonas salmonicida were recorded during the monitoring...

  16. Benfang Lei’s research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS)and horse pathogen Streptococcus equi(S.equi). His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S.equi pathogenesis.Heme is an important source of essential iron for bacterial pathogens.Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS,demonstrated direct heme transfer from one protein to another,demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system,elucidated the activated heme transfer mechanism,and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction.These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Grampositive pathogens.Pathogenesis of GAS is mediated by an abundance of extracellular proteins,and pathogenic role and functional mechanism are not known for many of these virulence factors.Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination.These studies may lead to development of novel strategies to prevent and treat GAS infections.

  17. Coinfection of tick cell lines has variable effects on replication of intracellular bacterial and viral pathogens.

    Science.gov (United States)

    Moniuszko, Anna; Rückert, Claudia; Alberdi, M Pilar; Barry, Gerald; Stevenson, Brian; Fazakerley, John K; Kohl, Alain; Bell-Sakyi, Lesley

    2014-06-01

    Ticks transmit various human and animal microbial pathogens and may harbour more than one pathogen simultaneously. Both viruses and bacteria can trigger, and may subsequently suppress, vertebrate host and arthropod vector anti-microbial responses. Microbial coinfection of ticks could lead to an advantage or disadvantage for one or more of the microorganisms. In this preliminary study, cell lines derived from the ticks Ixodes scapularis and Ixodes ricinus were infected sequentially with 2 arthropod-borne pathogens, Borrelia burgdorferi s.s., Ehrlichia ruminantium, or Semliki Forest virus (SFV), and the effect of coinfection on the replication of these pathogens was measured. Prior infection of tick cell cultures with the spirochaete B. burgdorferi enhanced subsequent replication of the rickettsial pathogen E. ruminantium whereas addition of spirochaetes to cells infected with E. ruminantium had no effect on growth of the latter. Both prior and subsequent presence of B. burgdorferi also had a positive effect on SFV replication. Presence of E. ruminantium or SFV had no measurable effect on B. burgdorferi growth. In tick cells infected first with E. ruminantium and then with SFV, virus replication was significantly higher across all time points measured (24, 48, 72h post infection), while presence of the virus had no detectable effect on bacterial growth. When cells were infected first with SFV and then with E. ruminantium, there was no effect on replication of either pathogen. The results of this preliminary study indicate that interplay does occur between different pathogens during infection of tick cells. Further study is needed to determine if this results from direct pathogen-pathogen interaction or from effects on host cell defences, and to determine if these observations also apply in vivo in ticks. If presence of one pathogen in the tick vector results in increased replication of another, this could have implications for disease transmission and incidence.

  18. Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

    Directory of Open Access Journals (Sweden)

    Carl A. Batt

    2009-05-01

    Full Text Available The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform.

  19. Emerging bacterial pathogens and changing concepts of bacterial pathogenesis in cystic fibrosis.

    Science.gov (United States)

    Parkins, Michael D; Floto, R Andres

    2015-05-01

    Chronic suppurative lower airway infection is a hallmark feature of cystic fibrosis (CF). Decades of experience in clinical microbiology have enabled the development of improved technologies and approaches for the cultivation and identification of microorganisms from sputum. It is increasingly apparent that the microbial constituents of the lower airways in CF exist in a dynamic state. Indeed, while changes in prevalence of various pathogens occur through ageing, differences exist in successive cohorts of patients and between clinics, regions and countries. Classical pathogens such as Pseudomonas aeruginosa, Burkholderia cepacia complex and Staphylococcus aureus are increasingly being supplemented with new and emerging organisms rarely observed in other areas of medicine. Moreover, it is now recognized that common oropharyngeal organisms, previously presumed to be benign colonizers may contribute to disease progression. As infection remains the leading cause of morbidity and mortality in CF, an understanding of the epidemiology, risk factors for acquisition and natural history of infection including interactions between colonizing bacteria is required. Unified approaches to the study and determination of pathogen status are similarly needed. Furthermore, experienced and evidence-based treatment data is necessary to optimize outcomes for individuals with CF.

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

    Directory of Open Access Journals (Sweden)

    Yuki Furuse

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

  1. Daily variations in pathogenic bacterial populations in a monsoon influenced tropical environment.

    Science.gov (United States)

    Khandeparker, Lidita; Anil, Arga Chandrashekar; Naik, Sneha D; Gaonkar, Chetan C

    2015-07-15

    Changing climatic conditions have influenced the monsoon pattern in recent years. Variations in bacterial population in one such tropical environment were observed everyday over two years and point out intra and inter annual changes driven by the intensity of rainfall. Vibrio spp. were abundant during the monsoon and so were faecal coliforms. Vibrio alginolyticus were negatively influenced by nitrate, whereas, silicate and rainfall positively influenced Vibrio parahaemolyticus numbers. It is also known that pathogenic bacteria are associated with the plankton. Changes in the abundance of plankton, which are governed mainly by environmental changes, could be responsible for variation in pathogenic bacterial abundance during monsoon, other than the land runoff due to precipitation and influx of fresh water.

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

    OpenAIRE

    Davin-Regli, Anne,; Pagès, Jean-Marie

    2015-01-01

    International audience; Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membra...

  3. Fluorescence in situ hybridization for the tissue detection of bacterial pathogens associated with porcine infections

    DEFF Research Database (Denmark)

    Jensen, Henrik Elvang; Jensen, Louise Kruse; Barington, Kristiane

    2015-01-01

    sequences within intact cells. FISH allows direct histological localization of the bacteria in the tissue and thereby a correlation between the infection and the histopathological changes present. This chapter presents protocols for FISH identification of bacterial pathogens in fixed deparaffinized tissue......Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary target...

  4. Fluorescence In Situ Hybridization for the Tissue Detection of Bacterial Pathogens Associated with Porcine Infections

    DEFF Research Database (Denmark)

    Elvang Jensen, Henrik; Jensen, Louise Kruse; Barington, Kristiane

    2015-01-01

    sequences within intact cells. FISH allows direct histological localization of the bacteria in the tissue and thereby a correlation between the infection and the histopathological changes present. This chapter presents protocols for FISH identification of bacterial pathogens in fixed deparaffinized tissue......Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary target...

  5. Interactions among Strategies Associated with Bacterial Infection: Pathogenicity, Epidemicity, and Antibiotic Resistance†

    OpenAIRE

    Martínez, José L; Baquero, Fernando

    2002-01-01

    Infections have been the major cause of disease throughout the history of human populations. With the introduction of antibiotics, it was thought that this problem should disappear. However, bacteria have been able to evolve to become antibiotic resistant. Nowadays, a proficient pathogen must be virulent, epidemic, and resistant to antibiotics. Analysis of the interplay among these features of bacterial populations is needed to predict the future of infectious diseases. In this regard, we hav...

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

    Directory of Open Access Journals (Sweden)

    Dominique Colinet

    2007-12-01

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

  7. Associations between vaginal pathogenic community and bacterial vaginosis in Chinese reproductive-age women.

    Science.gov (United States)

    Ling, Zongxin; Liu, Xia; Luo, Yueqiu; Wu, Xiaoxing; Yuan, Li; Tong, Xiaojuan; Li, Lanjuan; Xiang, Charlie

    2013-01-01

    Bacterial vaginosis (BV) is one of the most common urogenital infections among women of reproductive age that represents shifts in microbiota from Lactobacillus spp. to diverse anaerobes. The aim of our study was to evalute the diagnostic values of Gardnerella, Atopobium, Eggerthella, Megasphaera typeI, Leptotrichia/Sneathia and Prevotella, defined as a vaginal pathogenic community for BV and their associations with vaginal pH and Nugent scores. We investigated the vaginal pathogenic bacteria and Lactobacillus spp. with species-specific real-time quantitative PCR (qPCR) in 50 BV-positive and 50 BV-negative Chinese women of reproductive age. Relative to BV-negative subjects, a siginificant decline in Lactobacillus and an obvious increase in bacteria in the vaginal pathogenic community were observed in BV-postive subjects (P<0.05). With the exception of Megasphaera typeI, other vaginal pathogenic bacteria were highly predictable for BV with a better sensitivity and specificity. The vaginal pathogenic community was positively associated with vaginal pH and Nugent scores, while Lactobacillus spp., such as L. iners and L. crispatus was negatively associated with them (P<0.05). Our data implied that the prevalance of vaginal pathogenic bacteria as well as the depletion of Lactobacillus was highly accurate for BV diagnosis. Vaginal microbiota shifts, especially the overgrowth of the vaginal pathogenic community, showed well diagnostic values in predicting BV. Postive correlations between those vaginal pathogenic bacteria and vaginal pH, Nugent score indicated the vaginal pathogenic community rather than a single vaginal microorganism, was participated in the onset of BV directly.

  8. Coinfection of tick cell lines has variable effects on replication of intracellular bacterial and viral pathogens

    Science.gov (United States)

    Moniuszko, Anna; Rückert, Claudia; Alberdi, M. Pilar; Barry, Gerald; Stevenson, Brian; Fazakerley, John K.; Kohl, Alain; Bell-Sakyi, Lesley

    2014-01-01

    Ticks transmit various human and animal microbial pathogens and may harbour more than one pathogen simultaneously. Both viruses and bacteria can trigger, and may subsequently suppress, vertebrate host and arthropod vector anti-microbial responses. Microbial coinfection of ticks could lead to an advantage or disadvantage for one or more of the microorganisms. In this preliminary study, cell lines derived from the ticks Ixodes scapularis and Ixodes ricinus were infected sequentially with 2 arthropod-borne pathogens, Borrelia burgdorferi s.s., Ehrlichia ruminantium, or Semliki Forest virus (SFV), and the effect of coinfection on the replication of these pathogens was measured. Prior infection of tick cell cultures with the spirochaete B. burgdorferi enhanced subsequent replication of the rickettsial pathogen E. ruminantium whereas addition of spirochaetes to cells infected with E. ruminantium had no effect on growth of the latter. Both prior and subsequent presence of B. burgdorferi also had a positive effect on SFV replication. Presence of E. ruminantium or SFV had no measurable effect on B. burgdorferi growth. In tick cells infected first with E. ruminantium and then with SFV, virus replication was significantly higher across all time points measured (24, 48, 72 h post infection), while presence of the virus had no detectable effect on bacterial growth. When cells were infected first with SFV and then with E. ruminantium, there was no effect on replication of either pathogen. The results of this preliminary study indicate that interplay does occur between different pathogens during infection of tick cells. Further study is needed to determine if this results from direct pathogen–pathogen interaction or from effects on host cell defences, and to determine if these observations also apply in vivo in ticks. If presence of one pathogen in the tick vector results in increased replication of another, this could have implications for disease transmission and incidence

  9. Atypical sensors for direct and rapid neuronal detection of bacterial pathogens.

    Science.gov (United States)

    Lim, Ji Yeon; Choi, Seung-In; Choi, Geunyeol; Hwang, Sun Wook

    2016-03-09

    Bacterial infection can threaten the normal biological functions of a host, often leading to a disease. Hosts have developed complex immune systems to cope with the danger. Preceding the elimination of pathogens, selective recognition of the non-self invaders is necessary. At the forefront of the body's defenses are the innate immune cells, which are equipped with particular sensor molecules that can detect common exterior patterns of invading pathogens and their secreting toxins as well as with phagocytic machinery. Inflammatory mediators and cytokines released from these innate immune cells and infected tissues can boost the inflammatory cascade and further recruit adaptive immune cells to maximize the elimination and resolution. The nervous system also seems to interact with this process, mostly known to be affected by the inflammatory mediators through the binding of neuronal receptors, consequently activating neural circuits that tune the local and systemic inflammatory states. Recent research has suggested new contact points: direct interactions of sensory neurons with pathogens. Latest findings demonstrated that the sensory neurons not only share pattern recognition mechanisms with innate immune cells, but also utilize endogenous and exogenous electrogenic components for bacterial pathogen detection, by which the electrical firing prompts faster information flow than what could be achieved when the immune system is solely involved. As a result, rapid pain generation and active accommodation of the immune status occur. Here we introduced the sensory neuron-specific detector molecules for directly responding to bacterial pathogens and their signaling mechanisms. We also discussed extended issues that need to be explored in the future.

  10. Insights into the emergent bacterial pathogen Cronobacter spp., generated by multilocus sequence typing and analysis

    Directory of Open Access Journals (Sweden)

    Susan eJoseph

    2012-11-01

    Full Text Available Cronobacter spp. (previously known as Enterobacter sakazakii is a bacterial pathogen affecting all age groups, with particularly severe clinical complications in neonates and infants. One recognised route of infection being the consumption of contaminated infant formula. As a recently recognised bacterial pathogen of considerable importance and regulatory control, appropriate detection and identification schemes are required. The application of multilocus sequence typing (MLST and analysis (MLSA of the seven alleles atpD, fusA, glnS, gltB, gyrB, infB and ppsA (concatenated length 3036 base pairs has led to considerable advances in our understanding of the genus. This approach is supported by both the reliability of DNA sequencing over subjective phenotyping and the establishment of a MLST database which has open access and is also curated; http://www.pubMLST.org/cronobacter. MLST has been used to describe the diversity of the newly recognised genus, instrumental in the formal recognition of new Cronobacter species (C. universalis and C. condimenti and revealed the high clonality of strains and the association of clonal complex 4 with neonatal meningitis cases. Clearly the MLST approach has considerable benefits over the use of non-DNA sequence based methods of analysis for newly emergent bacterial pathogens. The application of MLST and MLSA has dramatically enabled us to better understand this opportunistic bacterium which can cause irreparable damage to a newborn baby’s brain, and has contributed to improved control measures to protect neonatal health.

  11. Bacterial pathogens activate a common inflammatory pathway through IFNλ regulation of PDCD4.

    Directory of Open Access Journals (Sweden)

    Taylor S Cohen

    Full Text Available The type III interferon (IFNλ receptor IL-28R is abundantly expressed in the respiratory tract and has been shown essential for host defense against some viral pathogens, however no data are available concerning its role in the innate immune response to bacterial pathogens. Staphylococcus aureus and Pseudomonas aeruginosa induced significant production of IFNλ in the lung, and clearance of these bacteria from the lung was significantly increased in IL-28R null mice compared to controls. Improved bacterial clearance correlated with reduced lung pathology and a reduced ratio of pro- vs anti-inflammatory cytokines in the airway. In human epithelial cells IFNλ inhibited miR-21 via STAT3 resulting in upregulation of PDCD4, a protein known to promote inflammatory signaling. In vivo 18 hours following infection with either pathogen, miR-21 was significantly reduced and PDCD4 increased in the lungs of wild type compared to IL-28R null mice. Infection of PDCD4 null mice with USA300 resulted in improved clearance, reduced pathology, and reduced inflammatory cytokine production. These data suggest that during bacterial pneumonia IFNλ promotes inflammation by inhibiting miR-21 regulation of PDCD4.

  12. Bacteriocin from Bacillus subtilis as a novel drug against diabetic foot ulcer bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Baby Joseph; Berlina Dhas; Vimalin Hena; Justin Raj

    2013-01-01

    Objective:To isolate and identify Bacillus subtilis (B. subtilis) from soil and to characterize and partially purify the bacteriocin. To evaluate the antimicrobial activity against four diabetic foot ulcer bacterial pathogens. Methods:Genotypic identification was done based on Bergey’s manual of systemic bacteriology. Antimicrobial susceptibility test was done by Kirby-Bauer disc diffusion method. Colonies were identified by colony morphology and biochemical characterization and also compared with MTCC 121 strain. Further identification was done by 16S rRNA sequencing. Inhibitory activities of partially purified bacteriocin on all the DFU isolates were done by agar well diffusion method. The strain was identified to produce bacteriocin by stab overlay assay. Bacteriocin was extracted by organic solvent extraction using chloroform, further purified by HPLC and physical, and chemical characterization was performed. Results: The four isolates showed high level of resistance to amoxyclav and sensitivity to ciprofloxacin. HPLC purification revealed that the extracts are bacteriocin. The phylogenetic tree analysis results showed that the isolate was 99%related to B. subtilis BSF01. The results reveled activity to all the four isolates and high level of activity was seen in case of Klebsiella sp. Conclusions:Partially purified bacteriocin was found to have antimicrobial activity against the four diabetic foot ulcer bacterial pathogens, which can thus be applied as a better drug molecule on further studies. The strain B. subtilis are found to be safe for use and these antimicrobial peptides can be used as an antimicrobial in humans to treat DFU bacterial pathogens.

  13. Insights into the Emergent Bacterial Pathogen Cronobacter spp., Generated by Multilocus Sequence Typing and Analysis.

    Science.gov (United States)

    Joseph, Susan; Forsythe, Stephen J

    2012-01-01

    Cronobacter spp. (previously known as Enterobacter sakazakii) is a bacterial pathogen affecting all age groups, with particularly severe clinical complications in neonates and infants. One recognized route of infection being the consumption of contaminated infant formula. As a recently recognized bacterial pathogen of considerable importance and regulatory control, appropriate detection, and identification schemes are required. The application of multilocus sequence typing (MLST) and analysis (MLSA) of the seven alleles atpD, fusA, glnS, gltB, gyrB, infB, and ppsA (concatenated length 3036 base pairs) has led to considerable advances in our understanding of the genus. This approach is supported by both the reliability of DNA sequencing over subjective phenotyping and the establishment of a MLST database which has open access and is also curated; http://www.pubMLST.org/cronobacter. MLST has been used to describe the diversity of the newly recognized genus, instrumental in the formal recognition of new Cronobacter species (C. universalis and C. condimenti) and revealed the high clonality of strains and the association of clonal complex 4 with neonatal meningitis cases. Clearly the MLST approach has considerable benefits over the use of non-DNA sequence based methods of analysis for newly emergent bacterial pathogens. The application of MLST and MLSA has dramatically enabled us to better understand this opportunistic bacterium which can cause irreparable damage to a newborn baby's brain, and has contributed to improved control measures to protect neonatal health.

  14. Exposure to viral and bacterial pathogens among Soay sheep (Ovis aries) of the St Kilda archipelago.

    Science.gov (United States)

    Graham, A L; Nussey, D H; Lloyd-Smith, J O; Longbottom, D; Maley, M; Pemberton, J M; Pilkington, J G; Prager, K C; Smith, L; Watt, K A; Wilson, K; McNEILLY, T N; Brülisauer, F

    2016-07-01

    We assessed evidence of exposure to viruses and bacteria in an unmanaged and long-isolated population of Soay sheep (Ovis aries) inhabiting Hirta, in the St Kilda archipelago, 65 km west of Benbecula in the Outer Hebrides of Scotland. The sheep harbour many metazoan and protozoan parasites but their exposure to viral and bacterial pathogens is unknown. We tested for herpes viral DNA in leucocytes and found that 21 of 42 tested sheep were infected with ovine herpesvirus 2 (OHV-2). We also tested 750 plasma samples collected between 1997 and 2010 for evidence of exposure to seven other viral and bacterial agents common in domestic Scottish sheep. We found evidence of exposure to Leptospira spp., with overall seroprevalence of 6·5%. However, serological evidence indicated that the population had not been exposed to border disease, parainfluenza, maedi-visna, or orf viruses, nor to Chlamydia abortus. Some sheep tested positive for antibodies against Mycobacterium avium subsp. paratuberculosis (MAP) but, in the absence of retrospective faecal samples, the presence of this infection could not be confirmed. The roles of importation, the pathogen-host interaction, nematode co-infection and local transmission warrant future investigation, to elucidate the transmission ecology and fitness effects of the few viral and bacterial pathogens on Hirta.

  15. Chemical communication in the gut: Effects of microbiota-generated metabolites on gastrointestinal bacterial pathogens.

    Science.gov (United States)

    Vogt, Stefanie L; Peña-Díaz, Jorge; Finlay, B Brett

    2015-08-01

    Gastrointestinal pathogens must overcome many obstacles in order to successfully colonize a host, not the least of which is the presence of the gut microbiota, the trillions of commensal microorganisms inhabiting mammals' digestive tracts, and their products. It is well established that a healthy gut microbiota provides its host with protection from numerous pathogens, including Salmonella species, Clostridium difficile, diarrheagenic Escherichia coli, and Vibrio cholerae. Conversely, pathogenic bacteria have evolved mechanisms to establish an infection and thrive in the face of fierce competition from the microbiota for space and nutrients. Here, we review the evidence that gut microbiota-generated metabolites play a key role in determining the outcome of infection by bacterial pathogens. By consuming and transforming dietary and host-produced metabolites, as well as secreting primary and secondary metabolites of their own, the microbiota define the chemical environment of the gut and often determine specific host responses. Although most gut microbiota-produced metabolites are currently uncharacterized, several well-studied molecules made or modified by the microbiota are known to affect the growth and virulence of pathogens, including short-chain fatty acids, succinate, mucin O-glycans, molecular hydrogen, secondary bile acids, and the AI-2 quorum sensing autoinducer. We also discuss challenges and possible approaches to further study of the chemical interplay between microbiota and gastrointestinal pathogens.

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

    Science.gov (United States)

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

    2016-06-01

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

  17. Diet and environment shape fecal bacterial microbiota composition and enteric pathogen load of grizzly bears.

    Directory of Open Access Journals (Sweden)

    Clarissa Schwab

    Full Text Available BACKGROUND: Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos and relates these to food resources consumed by bears. METHODOLOGY/PRINCIPAL FINDINGS: Feces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids. CONCLUSION: This is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens.

  18. Bacterial ‘Cell’ Phones: Do cell phones carry potential pathogens?

    Directory of Open Access Journals (Sweden)

    Kiran Chawla

    2009-05-01

    Full Text Available Cell phones are important companions for professionals especially health care workers (HCWs for better communication in hospital. The present study compared the nature of the growth of potentially pathogenic bacterial flora on cell phones in hospital and community. 75% cell phones from both the categories grew at least one potentially pathogenic organism. Cell phones from HCWs grew significantly more potential pathogens like MRSA (20%, Acinetobacter species (5%, Pseudomonas species (2.5% as compared to the non HCWs. 97.5% HCWs use their cell phone in the hospital, 57.5% never cleaned their cell phone and 20% admitted that they did not wash their hands before or after attending patients, although majority (77.5% knows that cell phones can have harmful colonization and act as vector for nosocomial infections. It is recommended, therefore, that cell phones in the hospital should be regularly decontaminated. Moreover, utmost emphasis needs to be paid to hand washing practices among HCWs.

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

    Science.gov (United States)

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

    2016-03-15

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

  20. Pathogenic reaction of some introduced rice cultivars (lines) to seven pathotypes of bacterial blight in Hangzhou

    Institute of Scientific and Technical Information of China (English)

    SHENYing; ZHUPeiliang; YUANXiaoping

    1993-01-01

    Bacterial blight (BB) caused by Xanthomonas oryzae pv.oryzae (Xoo) is a major rice disease in China. 138 introduced cultivars (lines) were tested on pathogenicity with seven pathotypes of BB at CNRRI Experiment Station during Apt-Oct,1991.

  1. A historical overview of bacteriophage therapy as an alternative to antibiotics for the treatment of bacterial pathogens.

    Science.gov (United States)

    Wittebole, Xavier; De Roock, Sophie; Opal, Steven M

    2014-01-01

    The seemingly inexorable spread of antibiotic resistance genes among microbial pathogens now threatens the long-term viability of our current antimicrobial therapy to treat severe bacterial infections such as sepsis. Antibiotic resistance is reaching a crisis situation in some bacterial pathogens where few therapeutic alternatives remain and pan-resistant strains are becoming more prevalent. Non-antibiotic therapies to treat bacterial infections are now under serious consideration and one possible option is the therapeutic use of specific phage particles that target bacterial pathogens. Bacteriophage therapy has essentially been re-discovered by modern medicine after widespread use of phage therapy in the pre-antibiotic era lost favor, at least in Western countries, after the introduction of antibiotics. We review the current therapeutic rationale and clinical experience with phage therapy as a treatment for invasive bacterial infection as novel alternative to antimicrobial chemotherapy.

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

    Directory of Open Access Journals (Sweden)

    Anju Pandey

    2010-01-01

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

  3. Multidirectional chemical signalling between Mammalian hosts, resident microbiota, and invasive pathogens: neuroendocrine hormone-induced changes in bacterial gene expression.

    Science.gov (United States)

    Karavolos, Michail H; Khan, C M Anjam

    2014-01-01

    Host-pathogen communication appears to be crucial in establishing the outcome of bacterial infections. There is increasing evidence to suggest that this communication can take place by bacterial pathogens sensing and subsequently responding to host neuroendocrine (NE) stress hormones. Bacterial pathogens have developed mechanisms allowing them to eavesdrop on these communication pathways within their hosts. These pathogens can use intercepted communication signals to adjust their fitness to persist and cause disease in their hosts. Recently, there have been numerous studies highlighting the ability of NE hormones to act as an environmental cue for pathogens, helping to steer their responses during host infection. Host NE hormone sensing can take place indirectly or directly via bacterial adrenergic receptors (BARs). The resulting changes in bacterial gene expression can be of strategic benefit to the pathogen. Furthermore, it is intriguing that not only can bacteria sense NE stress hormones but they are also able to produce key signalling molecules known as autoinducers. The rapid advances in our knowledge of the human microbiome, and its impact on health and disease highlights the potential importance of communication between the microbiota, pathogens and the host. It is indeed likely that the microbiota input significantly in the neuroendocrinological homeostasis of the host by catabolic, anabolic, and signalling processes. The arrival of unwanted guests, such as bacterial pathogens, clearly has a major impact on these delicately balanced interactions. Unravelling the pathways involved in interkingdom communication between invading bacterial pathogens, the resident microbiota, and hosts, may provide novel targets in our continuous search for new antimicrobials to control disease.

  4. Apoptosis, Toll-like, RIG-I-like and NOD-like Receptors Are Pathways Jointly Induced by Diverse Respiratory Bacterial and Viral Pathogens

    Science.gov (United States)

    Martínez, Isidoro; Oliveros, Juan C.; Cuesta, Isabel; de la Barrera, Jorge; Ausina, Vicente; Casals, Cristina; de Lorenzo, Alba; García, Ernesto; García-Fojeda, Belén; Garmendia, Junkal; González-Nicolau, Mar; Lacoma, Alicia; Menéndez, Margarita; Moranta, David; Nieto, Amelia; Ortín, Juan; Pérez-González, Alicia; Prat, Cristina; Ramos-Sevillano, Elisa; Regueiro, Verónica; Rodriguez-Frandsen, Ariel; Solís, Dolores; Yuste, José; Bengoechea, José A.; Melero, José A.

    2017-01-01

    Lower respiratory tract infections are among the top five leading causes of human death. Fighting these infections is therefore a world health priority. Searching for induced alterations in host gene expression shared by several relevant respiratory pathogens represents an alternative to identify new targets for wide-range host-oriented therapeutics. With this aim, alveolar macrophages were independently infected with three unrelated bacterial (Streptococcus pneumoniae, Klebsiella pneumoniae, and Staphylococcus aureus) and two dissimilar viral (respiratory syncytial virus and influenza A virus) respiratory pathogens, all of them highly relevant for human health. Cells were also activated with bacterial lipopolysaccharide (LPS) as a prototypical pathogen-associated molecular pattern. Patterns of differentially expressed cellular genes shared by the indicated pathogens were searched by microarray analysis. Most of the commonly up-regulated host genes were related to the innate immune response and/or apoptosis, with Toll-like, RIG-I-like and NOD-like receptors among the top 10 signaling pathways with over-expressed genes. These results identify new potential broad-spectrum targets to fight the important human infections caused by the bacteria and viruses studied here. PMID:28298903

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

    Science.gov (United States)

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

    2015-01-01

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

  6. Coexistence of emerging bacterial pathogens in Ixodes ricinus ticks in Serbia*

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    Tomanović S.

    2010-09-01

    Full Text Available The list of tick-borne pathogens is long, varied and includes viruses, bacteria, protozoa and nematodes. As all of these agents can exist in ticks, their co-infections have been previously reported. We studied co-infections of emerging bacterial pathogens (Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum and Francisella tularensis in Ixodes ricinus ticks in Serbia. Using PCR technique, we detected species-specific sequences, rrf-rrl rDNA intergenic spacer for B. burgdorferi s.l., p44/msp2 paralogs for A. phagocytophilum, and the 17 kDa lipoprotein gene, TUL4, for F. tularensis, respectively, in total DNA extracted from the ticks. Common infections with more than one pathogen were detected in 42 (28.8 % of 146 infected I. ricinus ticks. Co-infections with two pathogens were present in 39 (26.7 % of infected ticks. Simultaneous presence of A. phagocytophilum and different genospecies of B. burgdorferi s.l. complex was recorded in 16 ticks, co-infection with different B. burgdorferi s. l. genospecies was found in 15 ticks and eight ticks harbored mixed infections with F. tularensis and B. burgdorferi s.l. genospecies. Less common were triple pathogen species infections, detected in three ticks, one infected with A. phagocytophilum / B. burgdorferi s.s. / B. lusitaniae and two infected with F. tularensis / B. burgdorferi s.s. / B. lusitaniae. No mixed infections of A. phagocytophilum and F. tularensis were detected.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Law eJodi Woan-Fei

    2015-01-01

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

  9. Predicting the presence of bacterial pathogens in the airways of primary care patients with acute cough

    Science.gov (United States)

    Teepe, Jolien; Broekhuizen, Berna D.L.; Loens, Katherine; Lammens, Christine; Ieven, Margareta; Goossens, Herman; Little, Paul; Butler, Chris C.; Coenen, Samuel; Godycki-Cwirko, Maciek; Verheij, Theo J.M.

    2017-01-01

    -reactive protein showed diagnostic value for a bacterial cause. However, the ability of these diagnostic indicators to exclude a bacterial cause was limited. Procalcitonin added no clinically relevant information. PMID:27777252

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

    Directory of Open Access Journals (Sweden)

    Siripun Sarin

    2011-01-01

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

  11. Phage-protease-peptide: a novel trifecta enabling multiplex detection of viable bacterial pathogens.

    Science.gov (United States)

    Alcaine, S D; Tilton, L; Serrano, M A C; Wang, M; Vachet, R W; Nugen, S R

    2015-10-01

    Bacteriophages represent rapid, readily targeted, and easily produced molecular probes for the detection of bacterial pathogens. Molecular biology techniques have allowed researchers to make significant advances in the bioengineering of bacteriophage to further improve speed and sensitivity of detection. Despite their host specificity, bacteriophages have not been meaningfully leveraged in multiplex detection of bacterial pathogens. We propose a proof-of-principal phage-based scheme to enable multiplex detection. Our scheme involves bioengineering bacteriophage to carry a gene for a specific protease, which is expressed during infection of the target cell. Upon lysis, the protease is released to cleave a reporter peptide, and the signal detected. Here we demonstrate the successful (i) modification of T7 bacteriophage to carry tobacco etch virus (TEV) protease; (ii) expression of TEV protease by Escherichia coli following infection by our modified T7, an average of 2000 units of protease per phage are produced during infection; and (iii) proof-of-principle detection of E. coli in 3 h after a primary enrichment via TEV protease activity using a fluorescent peptide and using a designed target peptide for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF MS) analysis. This proof-of-principle can be translated to other phage-protease-peptide combinations to enable multiplex bacterial detection and readily adopted on multiple platforms, like MALDI-TOF MS or fluorescent readers, commonly found in labs.

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

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    Qiaolin Dong

    2016-07-01

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

  13. Research Status and Prospect ofBurkholderia glumae, the Pathogen Causing Bacterial Panicle Blight

    Institute of Scientific and Technical Information of China (English)

    CUI Zhou-qi; ZHU Bo; XIE Guan-lin; LI Bin; HUANG Shi-wen

    2016-01-01

    Bacterial panicle blight caused by Burkholderia glumae is one of the most severe seed-borne bacterial diseases of rice in the world. Currently, this disease has affected many countries of Asia, Africa, South and North America. It is a typical example of the shifting from minor plant disease to major disease due to the changes of environmental conditions. Some virulent factors of B. glumae have been identified, including toxoflavins and lipases, whose productions are dependent on the TofI/TofR quorum-sensing system, and type III effectors. In spite of its economic significance, neither effective control measure for this disease nor resistant rice variety is currently available. In recent years, genomics, transcriptomics and other molecular methods have provided useful information for better understanding the molecular mechanisms underlyingB. glumaevirulence and the rice defence mechanisms against pathogens. For the prevention of this pathogen, our laboratory has developed a rapid and sensitive multiplex PCR assay for detecting and distinguishingB. glumae from otherBurkholderia species. This improved understanding ofB. glumae will shed new light on bacterial panicle blight disease management.

  14. Research Status and Prospect of Burkholderia glumae, the Pathogen Causing Bacterial Panicle Blight

    Directory of Open Access Journals (Sweden)

    Cui Zhou-qi

    2016-05-01

    Full Text Available Bacterial panicle blight caused by Burkholderia glumae is one of the most severe seed-borne bacterial diseases of rice in the world. Currently, this disease has affected many countries of Asia, Africa, South and North America. It is a typical example of the shifting from minor plant disease to major disease due to the changes of environmental conditions. Some virulent factors of B. glumae have been identified, including toxoflavins and lipases, whose productions are dependent on the TofI/TofR quorum-sensing system, and type III effectors. In spite of its economic significance, neither effective control measure for this disease nor resistant rice variety is currently available. In recent years, genomics, transcriptomics and other molecular methods have provided useful information for better understanding the molecular mechanisms underlying B. glumae virulence and the rice defence mechanisms against pathogens. For the prevention of this pathogen, our laboratory has developed a rapid and sensitive multiplex PCR assay for detecting and distinguishing B. glumae from other Burkholderia species. This improved understanding of B. glumae will shed new light on bacterial panicle blight disease management.

  15. A Comparison between Transcriptome Sequencing and 16S Metagenomics for Detection of Bacterial Pathogens in Wildlife.

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    Maria Razzauti

    Full Text Available Rodents are major reservoirs of pathogens responsible for numerous zoonotic diseases in humans and livestock. Assessing their microbial diversity at both the individual and population level is crucial for monitoring endemic infections and revealing microbial association patterns within reservoirs. Recently, NGS approaches have been employed to characterize microbial communities of different ecosystems. Yet, their relative efficacy has not been assessed. Here, we compared two NGS approaches, RNA-Sequencing (RNA-Seq and 16S-metagenomics, assessing their ability to survey neglected zoonotic bacteria in rodent populations.We first extracted nucleic acids from the spleens of 190 voles collected in France. RNA extracts were pooled, randomly retro-transcribed, then RNA-Seq was performed using HiSeq. Assembled bacterial sequences were assigned to the closest taxon registered in GenBank. DNA extracts were analyzed via a 16S-metagenomics approach using two sequencers: the 454 GS-FLX and the MiSeq. The V4 region of the gene coding for 16S rRNA was amplified for each sample using barcoded universal primers. Amplicons were multiplexed and processed on the distinct sequencers. The resulting datasets were de-multiplexed, and each read was processed through a pipeline to be taxonomically classified using the Ribosomal Database Project. Altogether, 45 pathogenic bacterial genera were detected. The bacteria identified by RNA-Seq were comparable to those detected by 16S-metagenomics approach processed with MiSeq (16S-MiSeq. In contrast, 21 of these pathogens went unnoticed when the 16S-metagenomics approach was processed via 454-pyrosequencing (16S-454. In addition, the 16S-metagenomics approaches revealed a high level of coinfection in bank voles.We concluded that RNA-Seq and 16S-MiSeq are equally sensitive in detecting bacteria. Although only the 16S-MiSeq method enabled identification of bacteria in each individual reservoir, with subsequent derivation of

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

    Science.gov (United States)

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

    2015-01-01

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

  17. Vector-borne bacterial plant pathogens: Interactions with hemipteran insects and plants

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    Laura M Perilla-Henao

    2016-08-01

    Full Text Available Hemipteran insects are devastating pests of crops due to their wide host range, rapid reproduction, and ability to transmit numerous plant-infecting pathogens as vectors. While the field of plant-virus-vector interactions has flourished in recent years, plant-bacteria-vector interactions remain poorly understood. Leafhoppers and psyllids are by far the most important vectors of bacterial pathogens, yet there are still significant gaps in our understanding of their feeding behavior, salivary secretions, and plant responses as compared to important viral vectors, such as whiteflies and aphids. Even with an incomplete understanding of plant-bacteria-vector interactions, some common themes have emerged: 1 all known vector-borne bacteria share the ability to propagate in the plant and insect host; 2 particular hemipteran families appear to be incapable of transmitting vector-borne bacteria; 3 all known vector-borne bacteria have highly reduced genomes and coding capacity, resulting in host-dependence; and 4 vector-borne bacteria encode proteins that are essential for colonization of specific hosts, though only a few types of proteins have been investigated. Here, we review the current knowledge on important vector-borne bacterial pathogens, including Xylella fastidiosa, Spiroplasma spp., Liberibacter spp., and 'Candidatus Phytoplasma spp.’. We then highlight recent approaches used in the study of vector-borne bacteria. Finally, we discuss the application of this knowledge for control and future directions that will need to be addressed in the field of vector-plant-bacteria interactions.

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

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    Yamilé eLópez Hernández

    2015-02-01

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

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

    Science.gov (United States)

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

    2016-01-01

    Cattle manure harbors microbial constituents that make it a potential source of pollution in the environment and infections in humans. Knowledge of, and microbial assessment of, manure is crucial in a bid to prevent public health and environmental hazards through the development of better management practices and policies that should govern manure handling. Physical, chemical and biological methods to reduce pathogen population in manure do exist, but are faced with challenges such as cost, odor pollution, green house gas emission, etc. Consequently, anaerobic digestion of animal manure is currently one of the most widely used treatment method that can help to salvage the above-mentioned adverse effects and in addition, produces biogas that can serve as an alternative/complementary source of energy. However, this method has to be monitored closely as it could be fraught with challenges during operation, caused by the inherent characteristics of the manure. In addition, to further reduce bacterial pathogens to a significant level, anaerobic digestion can be combined with other methods such as thermal, aerobic and physical methods. In this paper, we review the bacterial composition of cattle manure as well as methods engaged in the control of pathogenic microbes present in manure and recommendations that need to be respected and implemented in order to prevent microbial contamination of the environment, animals and humans. PMID:27571092

  20. “Nothing is permanent but change”* -- Antigenic variation in persistent bacterial pathogens

    Science.gov (United States)

    Palmer, Guy H.; Bankhead, Troy; Lukehart, Sheila A.

    2012-01-01

    Summary Pathogens persist in immunocompetent mammalian hosts using various strategies, including evasion of immune effectors by antigenic variation. Among highly antigenically variant bacteria, gene conversion is used to generate novel expressed variants from otherwise silent donor sequences. Recombination using oligonucleotide segments from multiple donors is a combinatorial mechanism that tremendously expands the variant repertoire, allowing thousands of variants to be generated from a relatively small donor pool. Three bacterial pathogens, each encoded by a small genome (Borrelia burgdorferi VlsE diversity is encoded and expressed on a linear plasmid required for persistence and recent experiments have demonstrated that VlsE recombination is necessary for persistence in the immunocompetent host. In contrast, both Treponema pallidum TprK and Anaplasma marginale Msp2 expression sites and donors are chromosomally encoded. Both T. pallidum and A. marginale generate antigenic variants in vivo in individual hosts and studies at the population level reveal marked strain diversity in the variant repertoire that may underlie pathogen strain structure and the capacity for re-infection and heterologous strain superinfection. Here, we review gene conversion in bacterial antigenic variation and discuss the short- and long-term selective pressures that shape the variant repertoire. PMID:19709057

  1. 'Nothing is permanent but change'- antigenic variation in persistent bacterial pathogens.

    Science.gov (United States)

    Palmer, Guy H; Bankhead, Troy; Lukehart, Sheila A

    2009-12-01

    Pathogens persist in immunocompetent mammalian hosts using various strategies, including evasion of immune effectors by antigenic variation. Among highly antigenically variant bacteria, gene conversion is used to generate novel expressed variants from otherwise silent donor sequences. Recombination using oligonucleotide segments from multiple donors is a combinatorial mechanism that tremendously expands the variant repertoire, allowing thousands of variants to be generated from a relatively small donor pool. Three bacterial pathogens, each encoded by a small genome (Borrelia burgdorferi VlsE diversity is encoded and expressed on a linear plasmid required for persistence and recent experiments have demonstrated that VlsE recombination is necessary for persistence in the immunocompetent host. In contrast, both Treponema pallidum TprK and Anaplasma marginale Msp2 expression sites and donors are chromosomally encoded. Both T. pallidum and A. marginale generate antigenic variants in vivo in individual hosts and studies at the population level reveal marked strain diversity in the variant repertoire that may underlie pathogen strain structure and the capacity for re-infection and heterologous strain superinfection. Here, we review gene conversion in bacterial antigenic variation and discuss the short- and long-term selective pressures that shape the variant repertoire.

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

    Science.gov (United States)

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

    2015-01-01

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

  3. Putrescine regulating by stress-responsive MAPK cascade contributes to bacterial pathogen defense in Arabidopsis.

    Science.gov (United States)

    Kim, Su-Hyun; Kim, Sun-Hwa; Yoo, Seung-Jin; Min, Kwang-Hyun; Nam, Seung-Hee; Cho, Baik Ho; Yang, Kwang-Yeol

    2013-08-09

    Polyamines in plants are involved in various physiological and developmental processes including abiotic and biotic stress responses. We investigated the expression of ADCs, which are key enzymes in putrescine (Put) biosynthesis, and roles of Put involving defense response in Arabidopsis. The increased expression of ADC1 and ADC2, and the induction of Put were detected in GVG-NtMEK2(DD) transgenic Arabidopsis, whereas, their performance was partially compromised in GVG-NtMEK2(DD)/mpk3 and GVG-NtMEK2(DD)/mpk6 mutant following DEX treatment. The expression of ADC2 was highly induced by Pst DC3000 inoculation, while the transcript levels of ADC1 were slightly up-regulated. Compared to the WT plant, Put content in the adc2 knock-out mutant was reduced after Pst DC3000 inoculation, and showed enhanced susceptibility to pathogen infection. The adc2 mutant exhibited reduced expression of PR-1 after bacterial infection and the growth of the pathogen was about 4-fold more than that in the WT plant. Furthermore, the disease susceptibility of the adc2 mutant was recovered by the addition of exogenous Put. Taken together, these results suggest that Arabidopsis MPK3 and MPK6 play a positive role in the regulation of Put biosynthesis, and that Put contributes to bacterial pathogen defense in Arabidopsis.

  4. Inactivation of Selected Bacterial Pathogens in Dairy Cattle Manure by Mesophilic Anaerobic Digestion (Balloon Type Digester

    Directory of Open Access Journals (Sweden)

    Christy E. Manyi-Loh

    2014-07-01

    Full Text Available Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%–99% reduced in the order: Campylobacter sp. (18 days < Escherichia coli sp. (62 days < Salmonella sp. (133 days from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure, respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.

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

    Science.gov (United States)

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

    2014-07-14

    Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.

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

    Directory of Open Access Journals (Sweden)

    Christy E. Manyi-Loh

    2016-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Marc J Struelens

    1998-09-01

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

  8. The global dispersion of pathogenic microorganisms by dust storms and its relevance to agriculture: Chapter 1

    Science.gov (United States)

    Gonzalez-Martin, Cristina; Teigell-Perez, Nuria; Valladares, Basilio; Griffin, Dale W.

    2014-01-01

    Dust storms move an estimated 500–5000 Tg of soil through Earth’s atmosphere every year. Dust-storm transport of topsoils may have positive effects such as fertilization of aquatic and terrestrial ecosystems and the evolution of soils in proximal and distal environments. Negative effects may include the stripping of nutrient-rich topsoils from source regions, sandblasting of plant life in downwind environments, the fertilization of harmful algal blooms, and the transport of toxins (e.g., metals, pesticides, herbicides, etc.) and pathogenic microorganisms. With respect to the long-range dispersion of microorganisms and more specifically pathogens, research is just beginning to demonstrate the quantity and diversity of organisms that can survive this type of transport. Most studies to date have utilized different assays to identify microorganisms and microbial communities using predominately culture-based, and more recently nonculture-based, methodologies. There is a clear need for international-scale research efforts that apply standardized methods to advance this field of science. Here we present a review of dust-borne microorganisms with a focus on their relevance to agronomy.

  9. Colonization, pathogenicity, host susceptibility, and therapeutics for Staphylococcus aureus: what is the clinical relevance?

    Science.gov (United States)

    Tong, Steven Y C; Chen, Luke F; Fowler, Vance G

    2012-03-01

    Staphylococcus aureus is a human commensal that can also cause a broad spectrum of clinical disease. Factors associated with clinical disease are myriad and dynamic and include pathogen virulence, antimicrobial resistance, and host susceptibility. Additionally, infection control measures aimed at the environmental niches of S. aureus and therapeutic advances continue to impact upon the incidence and outcomes of staphylococcal infections. This review article focuses on the clinical relevance of advances in our understanding of staphylococcal colonization, virulence, host susceptibility, and therapeutics. Over the past decade key developments have arisen. First, rates of nosocomial methicillin-resistant S. aureus (MRSA) infections have significantly declined in many countries. Second, we have made great strides in our understanding of the molecular pathogenesis of S. aureus in general and community-associated MRSA in particular. Third, host risk factors for invasive staphylococcal infections, such as advancing age, increasing numbers of invasive medical interventions, and a growing proportion of patients with healthcare contact, remain dynamic. Finally, several new antimicrobial agents active against MRSA have become available for clinical use. Humans and S. aureus co-exist, and the dynamic interface between host, pathogen, and our attempts to influence these interactions will continue to rapidly change. Although progress has been made in the past decade, we are likely to face further surprises such as the recent waves of community-associated MRSA.

  10. Functionally Relevant Residues of Cdr1p: A Multidrug ABC Transporter of Human Pathogenic Candida albicans

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    Rajendra Prasad

    2011-01-01

    Full Text Available Reduced intracellular accumulation of drugs (due to rapid efflux mediated by the efflux pump proteins belonging to ABC (ATP Binding Cassette and MFS (Major Facilitators superfamily is one of the most common strategies adopted by multidrug resistance (MDR pathogenic yeasts. To combat MDR, it is essential to understand the structure and function of these transporters so that inhibitors/modulators to these can be developed. The sequence alignments of the ABC transporters reveal selective divergence within much conserved domains of Nucleotide-Binding Domains (NBDs which is unique to all fungal transporters. Recently, the role of conserved but divergent residues of Candida Drug Resistance 1 (CDR1, an ABC drug transporter of human pathogenic Candida albicans, has been examined with regard to ATP binding and hydrolysis. In this paper, we focus on some of the recent advances on the relevance of divergent and conserved amino acids of CaCdr1p and also discuss as to how drug interacts with Trans Membrane Domains (TMDs residues for its extrusion from MDR cells.

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

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    Sumit Rishi

    2012-06-01

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

  12. Factors related to occurrence and distribution of selected bacterial and protozoan pathogens in Pennsylvania streams

    Science.gov (United States)

    Duris, Joseph W.; Reif, Andrew G.; Donna A. Crouse,; Isaacs, Natasha M.

    2013-01-01

    The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfbO157) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but notCryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfbO157, STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2

  13. Factors related to occurrence and distribution of selected bacterial and protozoan pathogens in Pennsylvania streams.

    Science.gov (United States)

    Duris, Joseph W; Reif, Andrew G; Krouse, Donna A; Isaacs, Natasha M

    2013-01-01

    The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfb(O157)) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but not Cryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfb(O157), STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2, stx1, and rfb

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

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    Maria Karanika

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

  15. Fecal indicators and bacterial pathogens in bottled water from Dhaka, Bangladesh.

    Science.gov (United States)

    Ahmed, W; Yusuf, R; Hasan, I; Ashraf, W; Goonetilleke, A; Toze, S; Gardner, T

    2013-01-01

    Forty-six bottled water samples representing 16 brands from Dhaka, Bangladesh were tested for the numbers of total coliforms, fecal indicator bacteria (i.e., thermotolerant Escherichia coli and Enterococcus spp.) and potential bacterial pathogens (i.e., Aeromonas hydrophila, Pseudomonas aeruginosa, Salmonella spp., and Shigella spp.). Among the 16 brands tested, 14 (86%), ten (63%) and seven (44%) were positive for total coliforms, E. coil and Enterococcus spp., respectively. Additionally, a further nine (56%), eight (50%), six (37%), and four (25%) brands were PCR positive for A. hydrophila lip, P. aeruginosa ETA, Salmonella spp. invA, and Shigella spp. ipaH genes, respectively. The numbers of bacterial pathogens in bottled water samples ranged from 28 ± 12 to 600 ± 45 (A. hydrophila lip gene), 180 ± 40 to 900 ± 200 (Salmonella spp. invA gene), 180 ± 40 to 1,300 ± 400 (P. aeruginosa ETA gene) genomic units per L of water. Shigella spp. ipaH gene was not quantifiable. Discrepancies were observed in terms of the occurrence of fecal indicators and bacterial pathogens. No correlations were observed between fecal indicators numbers and presence/absence of A. hydrophila lip (p = 0.245), Salmonella spp. invA (p = 0.433), Shigella spp. ipaH gene (p = 0.078), and P. aeruginosa ETA (p = 0.059) genes. Our results suggest that microbiological quality of bottled waters sold in Dhaka, Bangladesh is highly variable. To protect public health, stringent quality control is recommended for the bottled water industry in Bangladesh.

  16. Fecal indicators and bacterial pathogens in bottled water from Dhaka, Bangladesh

    Directory of Open Access Journals (Sweden)

    W. Ahmed

    2013-01-01

    Full Text Available Forty-six bottled water samples representing 16 brands from Dhaka, Bangladesh were tested for the numbers of total coliforms, fecal indicator bacteria (i.e., thermotolerant Escherichia coli and Enterococcus spp. and potential bacterial pathogens (i.e., Aeromonas hydrophil, Pseudomonas aeruginos, Salmonella spp., and Shigella spp.. Among the 16 brands tested, 14 (86%, ten (63% and seven (44% were positive for total coliforms, E. coil and Enterococcus spp., respectively. Additionally, a further nine (56%, eight (50%, six (37%, and four (25% brands were PCR positive for A. hydrophila lip, P. aeruginosa ETA, Salmonella spp. invA, and Shigella spp. ipaH genes, respectively. The numbers of bacterial pathogens in bottled water samples ranged from 28 ± 12 to 600 ± 45 (A. hydrophila lip gene, 180 ± 40 to 900 ± 200 (Salmonella spp. invA gene, 180 ± 40 to 1,300 ± 400 (P. aeruginosa ETA gene genomic units per L of water. Shigella spp. ipaH gene was not quantifiable. Discrepancies were observed in terms of the occurrence of fecal indicators and bacterial pathogens. No correlations were observed between fecal indicators numbers and presence/absence of A. hydrophila lip (p = 0.245, Salmonella spp. invA (p = 0.433, Shigella spp. ipaH gene (p = 0.078, and P. aeruginosa ETA (p = 0.059 genes. Our results suggest that microbiological quality of bottled waters sold in Dhaka, Bangladesh is highly variable. To protect public health, stringent quality control is recommended for the bottled water industry in Bangladesh.

  17. Immune Subversion and Quorum-Sensing Shape the Variation in Infectious Dose among Bacterial Pathogens

    Science.gov (United States)

    Gama, João Alves; Abby, Sophie S.; Vieira-Silva, Sara; Dionisio, Francisco; Rocha, Eduardo P. C.

    2012-01-01

    Many studies have been devoted to understand the mechanisms used by pathogenic bacteria to exploit human hosts. These mechanisms are very diverse in the detail, but share commonalities whose quantification should enlighten the evolution of virulence from both a molecular and an ecological perspective. We mined the literature for experimental data on infectious dose of bacterial pathogens in humans (ID50) and also for traits with which ID50 might be associated. These compilations were checked and complemented with genome analyses. We observed that ID50 varies in a continuous way by over 10 orders of magnitude. Low ID50 values are very strongly associated with the capacity of the bacteria to kill professional phagocytes or to survive in the intracellular milieu of these cells. Inversely, high ID50 values are associated with motile and fast-growing bacteria that use quorum-sensing based regulation of virulence factors expression. Infectious dose is not associated with genome size and shows insignificant phylogenetic inertia, in line with frequent virulence shifts associated with the horizontal gene transfer of a small number of virulence factors. Contrary to previous proposals, infectious dose shows little dependence on contact-dependent secretion systems and on the natural route of exposure. When all variables are combined, immune subversion and quorum-sensing are sufficient to explain two thirds of the variance in infectious dose. Our results show the key role of immune subversion in effective human infection by small bacterial populations. They also suggest that cooperative processes might be important for successful infection by bacteria with high ID50. Our results suggest that trade-offs between selection for population growth-related traits and selection for the ability to subvert the immune system shape bacterial infectiousness. Understanding these trade-offs provides guidelines to study the evolution of virulence and in particular the micro-evolutionary paths

  18. In Vitro Activity of Delafloxacin against Contemporary Bacterial Pathogens from the United States and Europe, 2014

    Science.gov (United States)

    Pfaller, M. A.; Sader, H. S.; Rhomberg, P. R.

    2017-01-01

    ABSTRACT The in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested. Delafloxacin was the most potent agent tested against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus, Streptococcus pneumoniae, viridans group streptococci, and beta-hemolytic streptococci and had activity similar to that of ciprofloxacin and levofloxacin against certain members of the Enterobacteriaceae. Overall, the broadest coverage of the tested pathogens (Gram-positive cocci and Gram-negative bacilli) was observed with meropenem and tigecycline in both Europe and the United States. Delafloxacin was shown to be active against organisms that may be encountered in acute bacterial skin and skin structure infections, respiratory infections, and urinary tract infections. PMID:28167542

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

    Directory of Open Access Journals (Sweden)

    D H Tambekar

    2011-01-01

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

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

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    Brandon Sit

    2015-08-01

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

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

    Science.gov (United States)

    Sit, Brandon; Crowley, Shauna M.; Bhullar, Kirandeep; Lai, Christine Chieh-Lin; Tang, Calvin; Hooda, Yogesh; Calmettes, Charles; Khambati, Husain; Ma, Caixia; Brumell, John H.; Schryvers, Anthony B.; Vallance, Bruce A.; Moraes, Trevor F.

    2015-01-01

    Efficient acquisition of extracellular nutrients is essential for bacterial pathogenesis, however the identities and mechanisms for transport of many of these substrates remain unclear. Here, we investigate the predicted iron-binding transporter AfuABC and its role in bacterial pathogenesis in vivo. By crystallographic, biophysical and in vivo approaches, we show that AfuABC is in fact a cyclic hexose/heptose-phosphate transporter with high selectivity and specificity for a set of ubiquitous metabolites (glucose-6-phosphate, fructose-6-phosphate and sedoheptulose-7-phosphate). AfuABC is conserved across a wide range of bacterial genera, including the enteric pathogens EHEC O157:H7 and its murine-specific relative Citrobacter rodentium, where it lies adjacent to genes implicated in sugar sensing and acquisition. C. rodentium ΔafuA was significantly impaired in an in vivo murine competitive assay as well as its ability to transmit infection from an afflicted to a naïve murine host. Sugar-phosphates were present in normal and infected intestinal mucus and stool samples, indicating that these metabolites are available within the intestinal lumen for enteric bacteria to import during infection. Our study shows that AfuABC-dependent uptake of sugar-phosphates plays a critical role during enteric bacterial infection and uncovers previously unrecognized roles for these metabolites as important contributors to successful pathogenesis. PMID:26295949

  2. Bioinhibition of diarrhogenic Gram-positive bacterial patho-gens by potential indigenous probiotics

    Institute of Scientific and Technical Information of China (English)

    Adenike A.O.Ogunshe

    2008-01-01

    High level infant mortality rates and onset of drug resistance has led into the possible development of indige-nous probiotics as alternative bacteriotherapy in the control of infantile bacterial diarrhoea.This study was to determine the in vitro inhibitory potential of four probiotic candidates obtained from Nigerian indigenous fer-mented foods and beverages and from faecal specimens of healthy infants on infantile Gram-positive diarrhogen-ic bacterial pathogens.Potential probiotic candidates,AAOOL4,L.reuteri AAOOCH1,L.plantarum AAOO25 NN and L.delbrueckii AAOOT20 were assayed for in vitro bactericidal effects on diarrhogenic bacte-rial test strains-Bacillus cereus 25S,B.cereus 32S,B.licheniformis 26S and B.licheniformis 39S.All the test strains inoculated into an industrial infant weaning food already seeded with the probiotic strains were sig-nificantly inhibited within 96 hours. L. acidophilus AAOOL4, L. reuteri AAOOCH1 , L. plantarum AAOO25 NN and L.delbrueckii AAOOT20 had in vitro bactericidal effects on bacteri isolates implicated in in-fantile diarrhoea,indicating the probiotic potential of the candidates.

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

    Science.gov (United States)

    Davin-Regli, Anne; Pagès, Jean-Marie

    2015-01-01

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

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

    Science.gov (United States)

    Peng, Mengfei; Bitsko, Elizabeth; Biswas, Debabrata

    2015-03-01

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

  5. The bacterial pangenome as a new tool for analysing pathogenic bacteria

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    L. Rouli

    2015-09-01

    Full Text Available The bacterial pangenome was introduced in 2005 and, in recent years, has been the subject of many studies. Thanks to progress in next-generation sequencing methods, the pangenome can be divided into two parts, the core (common to the studied strains and the accessory genome, offering a large panel of uses. In this review, we have presented the analysis methods, the pangenome composition and its application as a study of lifestyle. We have also shown that the pangenome may be used as a new tool for redefining the pathogenic species. We applied this to the Escherichia coli and Shigella species, which have been a subject of controversy regarding their taxonomic and pathogenic position.

  6. The bacterial pangenome as a new tool for analysing pathogenic bacteria.

    Science.gov (United States)

    Rouli, L; Merhej, V; Fournier, P-E; Raoult, D

    2015-09-01

    The bacterial pangenome was introduced in 2005 and, in recent years, has been the subject of many studies. Thanks to progress in next-generation sequencing methods, the pangenome can be divided into two parts, the core (common to the studied strains) and the accessory genome, offering a large panel of uses. In this review, we have presented the analysis methods, the pangenome composition and its application as a study of lifestyle. We have also shown that the pangenome may be used as a new tool for redefining the pathogenic species. We applied this to the Escherichia coli and Shigella species, which have been a subject of controversy regarding their taxonomic and pathogenic position.

  7. Seagrass ecosystems reduce exposure to bacterial pathogens of humans, fishes, and invertebrates.

    Science.gov (United States)

    Lamb, Joleah B; van de Water, Jeroen A J M; Bourne, David G; Altier, Craig; Hein, Margaux Y; Fiorenza, Evan A; Abu, Nur; Jompa, Jamaluddin; Harvell, C Drew

    2017-02-17

    Plants are important in urban environments for removing pathogens and improving water quality. Seagrass meadows are the most widespread coastal ecosystem on the planet. Although these plants are known to be associated with natural biocide production, they have not been evaluated for their ability to remove microbiological contamination. Using amplicon sequencing of the 16S ribosomal RNA gene, we found that when seagrass meadows are present, there was a 50% reduction in the relative abundance of potential bacterial pathogens capable of causing disease in humans and marine organisms. Moreover, field surveys of more than 8000 reef-building corals located adjacent to seagrass meadows showed twofold reductions in disease levels compared to corals at paired sites without adjacent seagrass meadows. These results highlight the importance of seagrass ecosystems to the health of humans and other organisms.

  8. Antibiofilm Activity of the Brown Alga Halidrys siliquosa against Clinically Relevant Human Pathogens

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    Alessandro Busetti

    2015-06-01

    Full Text Available The marine brown alga Halidrys siliquosa is known to produce compounds with antifouling activity against several marine bacteria. The aim of this study was to evaluate the antimicrobial and antibiofilm activity of organic extracts obtained from the marine brown alga H. siliquosa against a focused panel of clinically relevant human pathogens commonly associated with biofilm-related infections. The partially fractionated methanolic extract obtained from H. siliquosa collected along the shores of Co. Donegal; Ireland; displayed antimicrobial activity against bacteria of the genus Staphylococcus; Streptococcus; Enterococcus; Pseudomonas; Stenotrophomonas; and Chromobacterium with MIC and MBC values ranging from 0.0391 to 5 mg/mL. Biofilms of S. aureus MRSA were found to be susceptible to the algal methanolic extract with MBEC values ranging from 1.25 mg/mL to 5 mg/mL respectively. Confocal laser scanning microscopy using LIVE/DEAD staining confirmed the antimicrobial nature of the antibiofilm activity observed using the MBEC assay. A bioassay-guided fractionation method was developed yielding 10 active fractions from which to perform purification and structural elucidation of clinically-relevant antibiofilm compounds.

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

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    Guillermo eCebrián

    2016-05-01

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

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

    Science.gov (United States)

    Cebrián, Guillermo; Mañas, Pilar; Condón, Santiago

    2016-01-01

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

  11. Structure-Activity Relationships of Antimicrobial Gallic Acid Derivatives from Pomegranate and Acacia Fruit Extracts against Potato Bacterial Wilt Pathogen.

    Science.gov (United States)

    Farag, Mohamed A; Al-Mahdy, Dalia A; Salah El Dine, Riham; Fahmy, Sherifa; Yassin, Aymen; Porzel, Andrea; Brandt, Wolfgang

    2015-06-01

    Bacterial wilts of potato, tomato, pepper, and or eggplant caused by Ralstonia solanacearum are among the most serious plant diseases worldwide. In this study, the issue of developing bactericidal agents from natural sources against R. solanacearum derived from plant extracts was addressed. Extracts prepared from 25 plant species with antiseptic relevance in Egyptian folk medicine were screened for their antimicrobial properties against the potato pathogen R. solancearum by using the disc-zone inhibition assay and microtitre plate dilution method. Plants exhibiting notable antimicrobial activities against the tested pathogen include extracts from Acacia arabica and Punica granatum. Bioactivity-guided fractionation of A. arabica and P. granatum resulted in the isolation of bioactive compounds 3,5-dihydroxy-4-methoxybenzoic acid and gallic acid, in addition to epicatechin. All isolates displayed significant antimicrobial activities against R. solanacearum (MIC values 0.5-9 mg/ml), with 3,5-dihydroxy-4-methoxybenzoic acid being the most effective one with a MIC value of 0.47 mg/ml. We further performed a structure-activity relationship (SAR) study for the inhibition of R. solanacearum growth by ten natural, structurally related benzoic acids.

  12. New insight into bacterial zoonotic pathogens posing health hazards to humans

    Directory of Open Access Journals (Sweden)

    Marcin Ciszewski

    2014-12-01

    Full Text Available This article presents the problem of evolutionary changes of zoonotic pathogens responsible for human diseases. Everyone is exposed to the risk of zoonotic infection, particularly employees having direct contact with animals, i.e. veterinarians, breeders, butchers and workers of animal products’ processing industry. The article focuses on pathogens monitored by the European Centre for Disease Prevention and Control (ECDC, which has been collecting statistical data on zoonoses from all European Union countries for 19 years and publishing collected data in annual epidemiological reports. Currently, the most important 11 pathogens responsible for causing human zoonotic diseases are being monitored, of which seven are bacteria: Salmonella spp., Campylobacter spp., Listeria monocytogenes, Mycobacterium bovis, Brucella spp., Coxiella burnetti and Verotoxin- producing E. coli (VTEC / Shiga-like toxin producing E. coli (STEC. As particularly important are considered foodborne pathogens. The article also includes new emerging zoonotic bacteria, which are not currently monitored by ECDC but might pose a serious epidemiological problem in a foreseeable future: Streptococcus iniae, S. suis, S. dysgalactiae and staphylococci: Staphylococcus intermedius, S. pseudintermedius. Those species have just crossed the animal-human interspecies barrier. The exact mechanism of this phenomenon remains unknown, it is connected, however, with genetic variability, capability to survive in changing environment. These abilities derive from DNA rearrangement and horizontal gene transfer between bacterial cells. Substantial increase in the number of scientific publications on this subject, observed over the last few years, illustrates the importance of the problem. Med Pr 2014;65(6:819–829

  13. Molecular evidence for bacterial and protozoan pathogens in hard ticks from Romania.

    Science.gov (United States)

    Ionita, Mariana; Mitrea, Ioan Liviu; Pfister, Kurt; Hamel, Dietmar; Silaghi, Cornelia

    2013-09-01

    The aim of the present study was to provide a preliminary insight into the diversity of tick-borne pathogens circulating at the domestic host-tick interface in Romania. For this, feeding and questing ticks were analyzed by real-time polymerase chain reaction (PCR) for the presence of Anaplasma phagocytophilum, Anaplasma platys, Ehrlichia canis, Borrelia burgdorferi sensu latu, and by PCR and subsequent sequencing for Rickettsia spp., Babesia spp. and Theileria spp. A total of 382 ticks, encompassing 5 species from 4 genera, were collected in April-July 2010 from different areas of Romania; of them, 40 were questing ticks and the remainder was collected from naturally infested cattle, sheep, goats, horses or dogs. Tick species analyzed included Ixodes ricinus, Dermacentor marginatus, Hyalomma marginatum, Rhipicephalus bursa, and Rhipicephalus sanguineus. Four rickettsiae of the spotted fever group of zoonotic concern were identified for the first time in Romania: Rickettsia monacensis and Rickettsia helvetica in I. ricinus, and Rickettsia slovaca and Rickettsia raoultii in D. marginatus. Other zoonotic pathogens such as A. phagocytophilum, Borrelia afzelii, and Babesia microti were found in I. ricinus. Pathogens of veterinary importance were also identified, including Theileria equi in H. marginatum, Babesia occultans in D. marginatus and H. marginatum, Theileria orientalis/sergenti/buffeli-group in I. ricinus and in H. marginatum and E. canis in R. sanguineus. These findings show a wide distribution of very diverse bacterial and protozoan pathogens at the domestic host-tick interface in Romania, with the potential of causing both animal and human diseases.

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

    Science.gov (United States)

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

    2017-01-01

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

  15. Enhanced Disease Susceptibility1 Mediates Pathogen Resistance and Virulence Function of a Bacterial Effector in Soybean.

    Science.gov (United States)

    Wang, Jialin; Shine, M B; Gao, Qing-Ming; Navarre, Duroy; Jiang, Wei; Liu, Chunyan; Chen, Qingshan; Hu, Guohua; Kachroo, Aardra

    2014-05-28

    Enhanced disease susceptibility1 (EDS1) and phytoalexin deficient4 (PAD4) are well-known regulators of both basal and resistance (R) protein-mediated plant defense. We identified two EDS1-like (GmEDS1a/GmEDS1b) proteins and one PAD4-like (GmPAD4) protein that are required for resistance signaling in soybean (Glycine max). Consistent with their significant structural conservation to Arabidopsis (Arabidopsis thaliana) counterparts, constitutive expression of GmEDS1 or GmPAD4 complemented the pathogen resistance defects of Arabidopsis eds1 and pad4 mutants, respectively. Interestingly, however, the GmEDS1 and GmPAD4 did not complement pathogen-inducible salicylic acid accumulation in the eds1/pad4 mutants. Furthermore, the GmEDS1a/GmEDS1b proteins were unable to complement the turnip crinkle virus coat protein-mediated activation of the Arabidopsis R protein Hypersensitive reaction to Turnip crinkle virus (HRT), even though both interacted with HRT. Silencing GmEDS1a/GmEDS1b or GmPAD4 reduced basal and pathogen-inducible salicylic acid accumulation and enhanced soybean susceptibility to virulent pathogens. The GmEDS1a/GmEDS1b and GmPAD4 genes were also required for Resistance to Pseudomonas syringae pv glycinea2 (Rpg2)-mediated resistance to Pseudomonas syringae. Notably, the GmEDS1a/GmEDS1b proteins interacted with the cognate bacterial effector AvrA1 and were required for its virulence function in rpg2 plants. Together, these results show that despite significant structural similarities, conserved defense signaling components from diverse plants can differ in their functionalities. In addition, we demonstrate a role for GmEDS1 in regulating the virulence function of a bacterial effector.

  16. Pulmonary bacterial pathogens in cystic fibrosis patients and antibiotic therapy: a tool for the health workers.

    Science.gov (United States)

    Coutinho, Henrique Douglas M; Falcão-Silva, Vivyanne S; Gonçalves, Gregório Fernandes

    2008-11-07

    Cystic fibrosis is the most common and best known genetic disease involving a defect in transepithelial Cl- transport by mutations in the CF gene on chromosome 7, which codes for the cystic fibrosis transmembrane conductance regulator protein (CFTR). The most serious symptoms are observed in the lungs, augmenting the risk of bacterial infection. The objective of this review was to describe the bacterial pathogens colonizing patients with cystic fibrosis. A systematic search was conducted using the international bibliographic databanks SCIELO, HIGHWIRE, PUBMED, SCIRUS and LILACS to provide a useful and practical review for healthcare workers to make them aware of these microorganisms. Today, B. cepacia, P. aeruginosa and S. aureus are the most important infectious agents in cystic fibrosis patients. However, healthcare professionals must pay attention to emerging infectious agents in these patients, because they represent a potentially serious future problem. Therefore, these pathogens should be pointed out as a risk to these patients, and hospitals all over the world must be prepared to detect and combat these bacteria.

  17. Screening of Quercus infectoria gall extracts as anti-bacterial agents against dental pathogens.

    Science.gov (United States)

    Vermani, Archa

    2009-01-01

    A number of bacteria have now become antibiotic-resistant. This increases the importance of ayurvedic drugs. We report, here, the activity of different extracts (petroleum ether, chloroform, methanol and water) of Quercus infectoria galls against dental pathogens -- Streptococcus mutans, Streptococcus salivarius, Staphylococcus aureus, Lactobacillus acidophilus (designated) and Streptococcus sanguis (isolated). The cup-plate method was used in anti-bacterial activity of the extracts at concentration of 200 mg/ml against dental pathogens. Minimum inhibitory concentration (MIC) values of most effective extracts against the most susceptible bacteria were determined using a two-fold serial micro dilution method. Methanolic extract showed maximum anti-bacterial activity against all the bacteria. The most susceptible bacteria were S. sanguis followed by S. aureus, S. mutans, S. salivarius and L. acidophilus. The MIC values showed that methanolic extract was more effective than water extract. The plant has the potential to generate herbal metabolites. The crude extracts demonstrating anti-dental caries activity could result in the discovery of new chemical classes of antibiotics. These chemical classes of antibiotics could serve as selective agents for the maintenance of human health and provide bio-chemical tools for the study of infectious diseases.

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

    Directory of Open Access Journals (Sweden)

    Jordan Lee Harris

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

  19. Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital, Indonesia

    Institute of Scientific and Technical Information of China (English)

    Maksum Radji; Siti Fauziah; Nurgani Aribinuko

    2011-01-01

    Objective: To evaluate the sensitivity pattern of bacterial pathogens in the intensive care unit (ICU) of a tertiary care of Fatmawati Hospital Jakarta Indonesia. Methods: A cross sectional retrospective study of bacterial pathogen was carried out on a total of 722 patients that were admitted to the ICU of Fatmawati Hospital Jakarta Indonesia during January 2009 to March 2010. All bacteria were identified by standard microbiologic methods, and their antibiotic susceptibility testing was performed using disk diffusion method. Results: Specimens were collected from 385 patients who were given antimicrobial treatment, of which 249 (64.68%) were cultured positive and 136 (35.32%) were negative. The most predominant isolate was Pseudomonas aeruginosa (P. aeruginosa) (26.5%) followed by Klebsiella pneumoniae (K. pneumoniae) (15.3%) and Staphylococcus epidermidis (14.9%). P. aeruginosa isolates showed high rate of resistance to cephalexin (95.3%), cefotaxime (64.1%), and ceftriaxone (60.9%). Amikacin was the most effective (84.4%) antibiotic against P. aeruginosa followed by imipenem (81.2%), and meropenem (75.0%). K. pneumoniae showed resistance to cephalexin (86.5%), ceftriaxone (75.7%), ceftazidime (73.0%), cefpirome (73.0%) and cefotaxime (67.9%), respectively. Conclusions: Most bacteria isolated from ICU of Fatmawati Hospital Jakarta Indonesia were resistant to the third generation of cephalosporins, and quinolone antibiotics. Regular surveillance of antibiotic susceptibility patterns is very important for setting orders to guide the clinician in choosing empirical or directed therapy of infected patients.

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

    KAUST Repository

    Ravasi, Timothy

    2016-01-24

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, Mark T.

    2001-03-13

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

  2. Pathogen identification with laser-induced breakdown spectroscopy: the effect of bacterial and biofluid specimen contamination.

    Science.gov (United States)

    Mohaidat, Qassem I; Sheikh, Khadija; Palchaudhuri, Sunil; Rehse, Steven J

    2012-03-01

    In this paper, the potential use of laser-induced breakdown spectroscopy (LIBS) for the rapid discrimination and identification of bacterial pathogens in realistic clinical specimens is investigated. Specifically, the common problem of sample contamination was studied by creating mixed samples to investigate the effect that the presence of a second contaminant bacterium in the specimen had on the LIBS-based identification of the primary pathogen. Two closely related bacterial specimens, Escherichia coli strain ATCC 25922 and Enterobacter cloacae strain ATCC 13047, were mixed together in mixing fractions of 10:1, 100:1, and 1000:1. LIBS spectra from the three mixtures were reliably classified as the correct E. coli strain with 98.5% accuracy when all the mixtures were withheld from the training model and classified against spectra from pure specimens. To simulate a rapid test for the presence of urinary tract infection pathogens, LIBS spectra were obtained from specimens of Staphylococcus epidermidis obtained from distilled water and sterile urine. LIBS spectra from the urine-harvested bacteria were classified as S. epidermidis with 100% accuracy when classified using a model containing only spectra from other Staphylococci species and with 88.5% accuracy when a model containing five genera of bacteria was utilized. Bacterial specimens comprising five different genera and 13 classifiable taxonomic groups of species and strains were compiled in a library that was tested using external validation techniques. The importance of utilizing external validation techniques where the library is tested with data withheld from all previous testing and training of the model was revealed by comparing the results against "leave-one-out" cross-validation results. Last, the effect of using sequential models for the classification of a single unknown spectrum was investigated by comparing the misclassification of two closely related bacteria, E. coli and E. cloacae, when the

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

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2014-01-01

    composition and bacterial pathogens were also studied. Microbial analysis was made by Ion Torrent sequencing of the PCR amplicons from ethidium monoazide treated samples, and ethidium monoazide was used to cleave DNA from dead cells and exclude it from PCR amplification. Both similarity and taxonomic analysis...... showed that the bacterial community composition in the influent was changed after anaerobic digestion. Firmicutes were dominant in all the samples, while Proteobacteria decreased in the biogas reactor compared with the influent. Variations of bacterial community composition in the biogas reactor...

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

    Science.gov (United States)

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

    2005-01-01

    Examination of finfish populations for viral and bacterial pathogens is an important component of fish disease control programs worldwide. Two methods are commonly used for collecting tissue samples for bacteriological culture, the currently accepted standards for detection of bacterial fish pathogens. The method specified in the Office International des Epizooties Manual of Diagnostic Tests for Aquatic Animals permits combining renal and splenic tissues from as many as 5 fish into pooled samples. The American Fisheries Society (AFS) Blue Book/US Fish and Wildlife Service (USFWS) Inspection Manual specifies the use of a bacteriological loop for collecting samples from the kidney of individual fish. An alternative would be to more fully utilize the pooled samples taken for virology. If implemented, this approach would provide substantial savings in labor and materials. To compare the relative performance of the AFS/USFWS method and this alternative approach, cultures of Yersinia ruckeri were used to establish low-level infections in groups of rainbow trout (Oncorhynchus mykiss) that were sampled by both methods. Yersinia ruckeri was cultured from 22 of 37 groups by at least 1 method. The loop method yielded 18 positive groups, with 1 group positive in the loop samples but negative in the pooled samples. The pooled samples produced 21 positive groups, with 4 groups positive in the pooled samples but negative in the loop samples. There was statistically significant agreement (Spearman coefficient 0.80, P < 0.001) in the relative ability of the 2 sampling methods to permit detection of low-level bacterial infections of rainbow trout.

  5. [Endophytic bacterial community analysis of Catharanthus roseus and its association with huanglongbing pathogen].

    Science.gov (United States)

    Li, Jia; Wang, Zhongkang; Xie, Pan; Wu, Dong; Yin, Youping

    2012-04-04

    To analyze the microbial diversity in healthy and HLB-affected Catharanthus roseus under manual-grafting conditions and to find the association between the endophytic bacteria and the HLB pathogen. The endophytic bacterial communities were delineated by using the traditional culturable approach and cultivation-independent techniques based on 16S rRNA gene. The endophytic bacteria were isolated from surface-sterilized C. roseus midribs of leaves and phloem of stems and roots by plating and restriction fragment length polymorphism (RFLP). By anaerobic culture, we obtained 67 strains that were identified 29 genus by GenBank. Curtobacterium sp. , Erwinia sp., Bacillus cereus and Brevundimonas sp. , Bacillus sp. were the dominant bacterial population in diseased and healthy C. roseus. However, Staphylococcus equorum was the common dominant isolate in both C. roseus. We picked 188 and 182 positive clones in 16S rDNA libraries of diseased and healthy C. roseus that were respectively restricted by the HaeIII, MspI, RsaI restriction endonuclease. Based on the similarity of the RFLP banding profiles in diseased and healthy C. roseus, we obtained 16, 23 OTUs (Operational Taxonomic Units, OTUs) respectively. In addition to Candidatus Liberibacter asiaticus, Candidatus Liberibacter sp. was the dominant bacterial population only in diseased C. roseus. With the infection of 'Ca. L. asiaticus', the diversity in diseased C. roseus decreased. The endophytic bacteria isolated from diseased and healthy C. roseus are abundant and have remarkable differences in the composition and function, suggesting that its endophytic bacteria might be inhibited by the HLB pathogen.

  6. Using lytic bacteriophages to eliminate or significantly reduce contamination of food by foodborne bacterial pathogens.

    Science.gov (United States)

    Sulakvelidze, Alexander

    2013-10-01

    Bacteriophages (also called 'phages') are viruses that kill bacteria. They are arguably the oldest (3 billion years old, by some estimates) and most ubiquitous (total number estimated to be 10(30) -10(32) ) known organisms on Earth. Phages play a key role in maintaining microbial balance in every ecosystem where bacteria exist, and they are part of the normal microflora of all fresh, unprocessed foods. Interest in various practical applications of bacteriophages has been gaining momentum recently, with perhaps the most attention focused on using them to improve food safety. That approach, called 'phage biocontrol', typically includes three main types of applications: (i) using phages to treat domesticated livestock in order to reduce their intestinal colonization with, and shedding of, specific bacterial pathogens; (ii) treatments for decontaminating inanimate surfaces in food-processing facilities and other food establishments, so that foods processed on those surfaces are not cross-contaminated with the targeted pathogens; and (iii) post-harvest treatments involving direct applications of phages onto the harvested foods. This mini-review primarily focuses on the last type of intervention, which has been gaining the most momentum recently. Indeed, the results of recent studies dealing with improving food safety, and several recent regulatory approvals of various commercial phage preparations developed for post-harvest food safety applications, strongly support the idea that lytic phages may provide a safe, environmentally-friendly, and effective approach for significantly reducing contamination of various foods with foodborne bacterial pathogens. However, some important technical and nontechnical problems may need to be addressed before phage biocontrol protocols can become an integral part of routine food safety intervention strategies implemented by food industries in the USA.

  7. Distinguishing bacterial pathogens of potato using a genome-wide microarray approach.

    Science.gov (United States)

    Aittamaa, M; Somervuo, P; Pirhonen, M; Mattinen, L; Nissinen, R; Auvinen, P; Valkonen, J P T

    2008-09-01

    A set of 9676 probes was designed for the most harmful bacterial pathogens of potato and tested in a microarray format. Gene-specific probes could be designed for all genes of Pectobacterium atrosepticum, c. 50% of the genes of Streptomyces scabies and c. 30% of the genes of Clavibacter michiganensis ssp. sepedonicus utilizing the whole-genome sequence information available. For Streptomyces turgidiscabies, 226 probes were designed according to the sequences of a pathogenicity island containing important virulence genes. In addition, probes were designed for the virulence-associated nip (necrosis-inducing protein) genes of P. atrosepticum, P. carotovorum and Dickeya dadantii and for the intergenic spacer (IGS) sequences of the 16S-23S rRNA gene region. Ralstonia solanacearum was not included in the study, because it is a quarantine organism and is not presently found in Finland, but a few probes were also designed for this species. The probes contained on average 40 target-specific nucleotides and were synthesized on the array in situ, organized as eight sub-arrays with an identical set of probes which could be used for hybridization with different samples. All bacteria were readily distinguished using a single channel system for signal detection. Nearly all of the c. 1000 probes designed for C. michiganensis ssp. sepedonicus, c. 50% and 40% of the c. 4000 probes designed for the genes of S. scabies and P. atrosepticum, respectively, and over 100 probes for S. turgidiscabies showed significant signals only with the respective species. P. atrosepticum, P. carotovorum and Dickeya strains were all detected with 110 common probes. By contrast, the strains of these species were found to differ in their signal profiles. Probes targeting the IGS region and nip genes could be used to place strains of Dickeya to two groups, which correlated with differences in virulence. Taken together, the approach of using a custom-designed, genome-wide microarray provided a robust means

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

    Directory of Open Access Journals (Sweden)

    Marie eBeaume

    2015-04-01

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

  9. How a bacterial pathogen swims in the storm stirred up by its coral host

    Science.gov (United States)

    Brumley, Douglas; Garren, Melissa; Fernandez, Vicente; Stocker, Roman

    2014-11-01

    One important cause of the worldwide demise of coral reefs is the infection of corals by pathogenic bacteria. These bacteria are always motile, yet how they land on the coral surface remains unclear. In particular, the recently discovered vortical flows produced by the coral with its epidermal cilia create a hostile hydrodynamic environment for motility and the pursuit of chemical cues. We used high-speed imaging coupled with dual-wavelength epifluorescent microscopy to track individual Vibrio coralliilyticus bacteria - known for causing coral disease - in the immediate vicinity of its host, the coral Pocillopora damicornis. By simultaneously determining the fluid velocity and bacterial trajectories, we quantified the ability of the bacteria to target the coral surface. We show that the cilia-driven flows considerably but not entirely disrupt bacterial navigation towards the coral, as a result of (i) the stirring of the chemical cues guiding the cells and (ii) the shear-induced alignment of bacteria within the flow. By enabling the direct visualization of microbial motility in ciliary flows, this system can not only provide insights into coral disease, but also serve as a model system for bacterial disease in other ciliated environments, including the human respiratory system.

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

    Science.gov (United States)

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

    2016-01-01

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

  11. Fluorocycline TP-271 Is Potent against Complicated Community-Acquired Bacterial Pneumonia Pathogens

    Science.gov (United States)

    Fyfe, Corey; O’Brien, William; Hackel, Meredith; Minyard, Mary Beth; Waites, Ken B.; Dubois, Jacques; Murphy, Timothy M.; Slee, Andrew M.; Weiss, William J.; Sutcliffe, Joyce A.

    2017-01-01

    ABSTRACT TP-271 is a novel, fully synthetic fluorocycline antibiotic in clinical development for the treatment of respiratory infections caused by susceptible and multidrug-resistant pathogens. TP-271 was active in MIC assays against key community respiratory Gram-positive and Gram-negative pathogens, including Streptococcus pneumoniae (MIC90 = 0.03 µg/ml), methicillin-sensitive Staphylococcus aureus (MSSA; MIC90 = 0.25 µg/ml), methicillin-resistant S. aureus (MRSA; MIC90 = 0.12 µg/ml), Streptococcus pyogenes (MIC90 = 0.03 µg/ml), Haemophilus influenzae (MIC90 = 0.12 µg/ml), and Moraxella catarrhalis (MIC90 ≤0.016 µg/ml). TP-271 showed activity (MIC90 = 0.12 µg/ml) against community-acquired MRSA expressing Panton-Valentine leukocidin (PVL). MIC90 values against Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae were 0.004, 1, and 4 µg/ml, respectively. TP-271 was efficacious in neutropenic and immunocompetent animal pneumonia models, generally showing, compared to the burden at the start of dosing, ~2 to 5 log10 CFU reductions against MRSA, S. pneumoniae, and H. influenzae infections when given intravenously (i.v.) and ~1 to 4 log10 CFU reductions when given orally (p.o.). TP-271 was potent against key community-acquired bacterial pneumonia (CABP) pathogens and was minimally affected, or unaffected, by tetracycline-specific resistance mechanisms and fluoroquinolone or macrolide drug resistance phenotypes. IMPORTANCE Rising resistance rates for macrolides, fluoroquinolones, and β-lactams in the most common pathogens associated with community-acquired bacterial pneumonia (CABP) are of concern, especially for cases of moderate to severe infections in vulnerable populations such as the very young and the elderly. New antibiotics that are active against multidrug-resistant Streptococcus pneumoniae and Staphylococcus aureus are needed for use in the empirical treatment of the most severe forms of this disease. TP-271 is a promising

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

    Directory of Open Access Journals (Sweden)

    Leonardo De La Fuente

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

  13. Facing the challenges of multiscale modelling of bacterial and fungal pathogen-host interactions.

    Science.gov (United States)

    Schleicher, Jana; Conrad, Theresia; Gustafsson, Mika; Cedersund, Gunnar; Guthke, Reinhard; Linde, Jörg

    2017-03-01

    Recent and rapidly evolving progress on high-throughput measurement techniques and computational performance has led to the emergence of new disciplines, such as systems medicine and translational systems biology. At the core of these disciplines lies the desire to produce multiscale models: mathematical models that integrate multiple scales of biological organization, ranging from molecular, cellular and tissue models to organ, whole-organism and population scale models. Using such models, hypotheses can systematically be tested. In this review, we present state-of-the-art multiscale modelling of bacterial and fungal infections, considering both the pathogen and host as well as their interaction. Multiscale modelling of the interactions of bacteria, especially Mycobacterium tuberculosis, with the human host is quite advanced. In contrast, models for fungal infections are still in their infancy, in particular regarding infections with the most important human pathogenic fungi, Candida albicans and Aspergillus fumigatus. We reflect on the current availability of computational approaches for multiscale modelling of host-pathogen interactions and point out current challenges. Finally, we provide an outlook for future requirements of multiscale modelling. © The Author 2016. Published by Oxford University Press.

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

    Directory of Open Access Journals (Sweden)

    David Duval

    2015-02-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  16. CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    S. Thangapandiyan and P. Prema*

    2012-05-01

    Full Text Available Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100µL/disc, the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%, Escherichia coli (62.50%, and Staphylococcus aureus (46% followed by rifampicin against Bacillus cereus (66.67% and kanamycin against Streptococcus epidermis (25%. These results signify that the silver nanoparticles showed potential antibacterial action of ß-lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.

  17. In Vitro Studies of the Activity of Dithiocarbamate Organoruthenium Complexes against Clinically Relevant Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Claudio L. Donnici

    2014-04-01

    Full Text Available The in vitro antifungal activity of nine dirutheniumpentadithiocarbamate complexes C1–C9 was investigated and assessed for its activity against four different fungal species with clinical interest and related to invasive fungal infections (IFIs, such as Candida spp. [C. albicans (two clinical isolates, C. glabrata, C. krusei, C. parapsolisis, C. tropicalis, C.dubliniensis (six clinical isolates], Paracoccidioides brasiliensis (seven clinical isolates, Cryptococcus neoformans and Sporothrix schenckii. All synthesized complexes C1–C9 and also the free ligands L1–L9 were submitted to in vitro tests against those fungi and the results are very promising, since some of the obtained MIC (minimal inhibitory concentration values were very low (from 10−6 mol mL−1 to 10−8 mol mL−1 against all investigated clinically relevant fungal pathogens, except for C. glabrata, that the MIC values are close to the ones obtained for fluconazole, the standard antifungal agent tested. Preliminary structure-activity relations (SAR might be suggested and a strong influence from steric and lipophilic parameters in the antifungal activity can be noticed. Cytotoxicity assays (IC50 showed that the complexes are not as toxic (IC50 values are much higher—30 to 200 fold—than MIC values. These ruthenium complexes are very promising lead compounds for novel antifungal drug development, especially in IFIs, one of most harmful emerging infection diseases (EIDs.

  18. Calcium homeostasis and signaling in fungi and their relevance for pathogenicity of yeasts and filamentous fungi

    Directory of Open Access Journals (Sweden)

    Renata Tisi

    2016-09-01

    Full Text Available Though fungi show peculiarities in the purposes and specific traits of calcium signaling pathways, the general scheme and the most important players are well conserved if compared to higher eukaryotes. This provides a powerful opportunity either to investigate shared features using yeast as a model or to exploit fungal specificities as potential targets for antifungal therapies. The sequenced genomes from yeast Saccharomyces cerevisiae, Schizosaccharomyces pombe and the filamentous fungus Neurospora crassa were already published more than ten years ago. More recently the genome sequences of filamentous fungi of Aspergillus genus, some of which threatening pathogens, and dimorphic fungi Ustilago maydis were published, giving the chance to identify several proteins involved in calcium signaling based on their homology to yeast or mammalian counterparts. Nonetheless, unidentified calcium transporters are still present in these organisms which await to be molecularly characterized. Despite the relative simplicity in yeast calcium machinery and the availability of sophisticated molecular tools, in the last years, a number of new actors have been identified, albeit not yet fully characterized. This review will try to describe the state of the art in calcium channels and calcium signaling knowledge in yeast, with particular attention to the relevance of this knowledge with respect to pathological fungi.

  19. Disability Adjusted Life Years and minimal disease: application of a preference-based relevance criterion to rank enteric pathogens

    Directory of Open Access Journals (Sweden)

    Haagsma Juanita A

    2008-12-01

    Full Text Available Abstract Background Burden of disease estimates, which combine mortality and morbidity into a single measure, are used increasingly for priority setting in disease control, prevention and surveillance. However, because there is no clear exclusion criterion for highly prevalent minimal disease in burden of disease studies its application may be restricted. The aim of this study was to apply a newly developed relevance criterion based on preferences of a population panel, and to compare burden of disease estimates of five foodborne pathogens calculated with and without application of this criterion. Methods Preferences for twenty health states associated with foodborne disease were obtained from a population panel (n = 107 with the Visual Analogue Scale and the Time Trade-off (TTO technique. The TTO preferences were used to derive the relevance criterion: if at least 50% of a panel of judges is willing to trade-off time in order to be restored to full health the health state is regarded as relevant, i.e. TTO median is greater than 0. Subsequently, the burden of disease of each of the five foodborne pathogens was calculated both with and without the relevance criterion. Results The panel ranked the health states consistently. Of the twenty health states, three did not meet the preference-based relevance criterion. Application of the relevance criterion reduced the burden of disease estimate of all five foodborne pathogens. The reduction was especially significant for norovirus and rotavirus, decreasing with 94% and 78% respectively. Conclusion Individual preferences elicited with the TTO from a population panel can be used to empirically derive a relevance criterion for burden of disease estimates. Application of this preference-based relevance criterion results in considerable changes in ranking of foodborne pathogens.

  20. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

    Science.gov (United States)

    Miller, Melissa A.; Byrne, Barbara A.; Jang, Spencer S.; Dodd, Erin M.; Dorfmeier, Elene; Harris, Michael D.; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A.; Miller, Woutrina A.

    2009-01-01

    Although protected for nearly a century, California’s sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

  1. Pathogenic Triad in Bacterial Meningitis: Pathogen Invasion, NF-κB Activation, and Leukocyte Transmigration that Occur at the Blood-Brain Barrier.

    Science.gov (United States)

    Wang, Shifu; Peng, Liang; Gai, Zhongtao; Zhang, Lehai; Jong, Ambrose; Cao, Hong; Huang, Sheng-He

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Sheng-He eHuang

    2016-02-01

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

  3. Essential roles for platelets during neutrophil-dependent or lymphocyte-mediated defense against bacterial pathogens.

    Science.gov (United States)

    Wang, Zheng; Zhao, Qi; Zhang, Dongxia; Sun, Chengming; Bao, Cuixia; Yi, Maoli; Xing, Li; Luo, Deyan

    2016-09-01

    Emerging evidence from animal models suggests that platelets may participate in a wide variety of processes including the immune response against infection. More than 200 whole blood samples from patients and healthy controls were run in the System XE-5000 analyzer, and plasma fractions were separated for the following tests by ELISA, Luminex and light scattering. We describe two mechanisms by which platelets may contribute to immune function against various bacterial pathogens based on increased mean platelet volume in gram-positive bacterial infections and increased platelet counts in gram-negative bacterial infections. Gram-negative bacteria activate platelets to recruit neutrophils, which participate in the immune response against infection. During this process, fractalkine, macrophage inflammatory protein-1β, interleukin-17A, tumor necrosis factor-α and platelet-activating factor were higher in patients infected with Escherichia coli; additionally, giant platelets were observed under the microscope. Meanwhile, we found that platelets played a different role in gram-positive bacterial infections. Specifically, they could actively adhere to gram-positive bacteria in circulation and transfer them to immune sites to promote antibacterial lymphocyte expansion. During this process, complement C3 and factor XI were more highly expressed in patients infected with Staphylococcus aureus; additionally, we detected more small platelets under the microscope. Platelets participate in the immune response against both gram-negative and gram-positive bacteria, although the mechanisms differ. These results will help us understand the complex roles of platelets during infections, and direct our use of antibiotics based on clinical platelet data.

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

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    Carrie L. Shaffer

    2016-04-01

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

  5. Internalization of bacterial pathogens in tomatoes and their control by selected chemicals.

    Science.gov (United States)

    Ibarra-Sánchez, L S; Alvarado-Casillas, S; Rodríguez-García, M O; Martínez-Gonzáles, N E; Castillo, A

    2004-07-01

    The effect of different washing or sanitizing agents was compared for preventing or reducing surface and internal contamination of tomatoes by Salmonella Typhimurium and Escherichia coli O157:H7. The tomatoes were inoculated by dipping them in a bacterial suspension containing approximately 6.0 log CFU/ml of each pathogen and then rinsing them with tap water, hypochlorite solution (250 mg/liter), or lactic acid solution (2%, wt/vol). All treatments were applied by dipping or spraying, and solutions were applied at 5, 25, 35, and 55 degrees C. With the exception of the lactic acid dip at 5 degrees C, all treatments reduced both pathogens on the surfaces of the tomatoes by at least 2.9 cycles. No significantly different results were obtained (P > 0.05) with the dipping and spraying techniques. For internalized pathogens, the mean counts for tomatoes treated with water alone or with chlorine ranged from 0.8 to 2.1 log CFU/g. In contrast, after lactic acid spray treatment, all core samples of tomatoes tested negative for Salmonella Typhimurium and, except for one sample with a low but detectable count, all samples tested negative for E. coli O157:H7 with a plate count method. When the absence of pathogens was verified by an enrichment method, Salmonella was not recovered from any samples, whereas two of four samples tested positive for E. coli O157:H7 even though the counts were negative. Few cells of internalized pathogens were able to survive in the center of the tomato during storage at room temperature (25 to 28 degrees C). The average superficial pH of tomatoes treated with tap water, chlorine, or lactic acid was 4.9 to 5.2, 4.1 to 4.3, and 2.5, respectively (P tomatoes treated with different sanitizers. The general practice in the tomato industry is to wash the tomatoes in chlorinated water. However, chlorine is rapidly degraded by organic matter usually present in produce. Therefore, lactic acid sprays may be a more effective alternative for decontaminating

  6. Piscirickettsia salmonis: a Gram-negative intracellular bacterial pathogen of fish.

    Science.gov (United States)

    Fryer, J L; Hedrick, R P

    2003-05-01

    Piscirickettsia salmonis is the first Gram-negative, intracellular bacterial pathogen isolated from fish and is a significant cause of mortality in salmonid fish. Recent reports of P. salmonis or P. salmonis-like organisms from new fish hosts and geographic regions have increased the interest in the bacterium. In this review, the important characteristics of the bacterium including recent taxonomic changes, features of the disease caused by the bacterium including transmission, hosts, reservoirs, diagnostic procedures, and current approaches for prevention and treatment have been discussed. The reader is also directed to other reviews concerning the bacterium and the disease it causes (Fryer & Lannan 1994, 1996; Almendras & Fuentealba 1997; Lannan, Bartholomew & Fryer 1999; House & Fryer 2002; Mauel & Miller 2002).

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

    Science.gov (United States)

    Doss, Janis; Culbertson, Kayla; Hahn, Delilah; Camacho, Joanna; Barekzi, Nazir

    2017-01-01

    Since the discovery of bacteriophage in the early 1900s, there have been numerous attempts to exploit their innate ability to kill bacteria. The purpose of this report is to review current findings and new developments in phage therapy with an emphasis on bacterial diseases of marine organisms, humans, and plants. The body of evidence includes data from studies investigating bacteriophage in marine and land environments as modern antimicrobial agents against harmful bacteria. The goal of this paper is to present an overview of the topic of phage therapy, the use of phage-derived protein therapy, and the hosts that bacteriophage are currently being used against, with an emphasis on the uses of bacteriophage against marine, human, animal and plant pathogens. PMID:28335451

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

    Directory of Open Access Journals (Sweden)

    Janis Doss

    2017-03-01

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

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

    Science.gov (United States)

    Doss, Janis; Culbertson, Kayla; Hahn, Delilah; Camacho, Joanna; Barekzi, Nazir

    2017-03-18

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

  10. Prevalence of potential bacterial respiratory pathogens in the oral cavity of hospitalised individuals.

    Science.gov (United States)

    Zuanazzi, David; Souto, Renata; Mattos, Marcelo Barbosa Accioly; Zuanazzi, Maura Rodrigues; Tura, Bernardo Rangel; Sansone, Carmelo; Colombo, Ana Paula Vieira

    2010-01-01

    To assess the prevalence of oral colonisation by bacterial respiratory pathogens in hospitalised patients. Thirty patients undergoing myocardium revascularisation surgery were evaluated. At baseline (pre-operative phase), full-mouth clinical periodontal assessment was performed. Saliva and biofilm samples were obtained from subjects at baseline and at the post-operative phase, after orotracheal extubation. DNA was extracted from samples and species of Acinetobacter, Pseudomonas, Staphylococcus aureus and Dialister pneumosintes were detected by PCR or culture (for staphylococci isolates). Most of the subjects were males, with history of hypertension and smoking. Thirteen were edentulous (ED) and 17 were dentate (DE), with moderate chronic periodontitis. The most prevalent bacteria in saliva were Staphylococcus spp. (85.7%), Pseudomonas spp. (83.8%), and Acinetobacter spp. (53.3%). There was a trend for D. pneumosintes to be more frequently detected in DE (43.7%) than ED (11.5%) patients. In plaque samples, DE with >14 teeth showed a higher prevalence of Pseudomonas spp. (100%) than individuals with 14 teeth (5.7%; p=0.037). All staphylococci isolates were coagulase-negative, and about 11% were positive for the mecA gene. These mecA-positive isolates showed a tendency to increase in all samples, whereas P. aeruginosa reduced after surgery. A strong correlation between the presence of Acinetobacter spp. and Pseudomonas spp. was observed (rho=0.886, ppatients harbours high frequencies of bacterial respiratory pathogens, supporting its potential role as a reservoir for these species. Copyright 2009 Elsevier Ltd. All rights reserved.

  11. Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital,Indonesia

    Institute of Scientific and Technical Information of China (English)

    Maksum; Radji; Siti; Fauziah; Nurgani; Aribinuko

    2011-01-01

    Objective:To evaluate the sensitivity pattern of bacterial pathogens in the intensive care unit(ICU) of a tertiary care of Falmawati Hospital Jakarta Indonesia.Methods:A cross sectional retrospective study of bacterial pathogen was carried out on a total of 722 patients that were admitted to the ICU of Fatmawati Hospital Jakarta Indonesia during January 2009 to March 2010. All bacteria were identified by standard microbiologic methods,and(heir antibiotic susceptibility testing was performed using disk diffusion method.Results:Specimens were collected from 385 patients who were given antimicrobial treatment,of which 249(64.68%) were cultured positive and 136(35.32%) were negative.The most predominant isolate was Pseudomonas aeruginosa(P.aeruginosa)(26.5%) followed by Klebsiella pneumoniae(K.pneumoniae)(15.3%) and Staphylococcus epidermidis(14.9%).P.aeruginosa isolates showed high rate of resistance to cephalexin(95.3%),cefotaxime(64.1%),and ceftriaxone(60.9%).Amikacin was the most effective(84.4%) antibiotic against P.aeruginosa followed by imipenem(81.2%),and meropenem(75.0%).K.pneumoniae showed resistance to cephalexin(86.5%),ceftriaxone(75.7%),ceftazidime(73.0%),cefpirome(73.0%) and cefotaxime(67.9%),respectively.Conclusions:Most bacteria isolated from ICU of Fatmawati Hospital Jakarta Indonesia were resistant to the third generation of cephalosporins,and quinolone antibiotics.Regular surveillance of antibiotic susceptibility pallerns is very important for setting orders to guide the clinician in choosing empirical or directed therapy of infected patients.

  12. Bacterial Adrenergic Sensors Regulate Virulence of Enteric Pathogens in the Gut

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    Cristiano G. Moreira

    2016-06-01

    Full Text Available Enteric pathogens such as enterohemorrhagic Escherichia coli (EHEC and Citrobacter rodentium, which is largely used as a surrogate EHEC model for murine infections, are exposed to several host neurotransmitters in the gut. An important chemical exchange within the gut involves the neurotransmitters epinephrine and/or norepinephrine, extensively reported to increase virulence gene expression in EHEC, acting through two bacterial adrenergic sensors: QseC and QseE. However, EHEC is unable to establish itself and cause its hallmark lesions, attaching and effacing (AE lesions, on murine enterocytes. To address the role of these neurotransmitters during enteric infection, we employed C. rodentium. Both EHEC and C. rodentium harbor the locus of enterocyte effacement (LEE that is necessary for AE lesion formation. Here we show that expression of the LEE, as well as that of other virulence genes in C. rodentium, is also activated by epinephrine and/or norepinephrine. Both QseC and QseE are required for LEE gene activation in C. rodentium, and the qseC and qseE mutants are attenuated for murine infection. C. rodentium has a decreased ability to colonize dopamine β-hydroxylase knockout (Dbh−/− mice, which do not produce epinephrine and norepinephrine. Both adrenergic sensors are required for C. rodentium to sense these neurotransmitters and activate the LEE genes during infection. These data indicate that epinephrine and norepinephrine are sensed by bacterial adrenergic receptors during enteric infection to promote activation of their virulence repertoire. This is the first report of the role of these neurotransmitters during mammalian gastrointestinal (GI infection by a noninvasive pathogen.

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

    Directory of Open Access Journals (Sweden)

    Ashkan Javid

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

  14. Lytic bacteriophages in Veterinary Medicine: a therapeutic option against bacterial pathogens?

    Directory of Open Access Journals (Sweden)

    C Borie

    2014-01-01

    Full Text Available The high prevalence of certain bacterial diseases in animals and their economic impact at the productive and public health levels, have directed attention towards the search for new methods of control and prevention, alternative or complementary, that aim to mitigate their adverse effects. This scenario is further complicated by the permanent and rising presence of pathogenic bacteria that are resistant to many antibiotics, limiting the choice of control strategies. In the continuous search for new therapies, there is a renewed interest on the application of bacteriophages, viruses that kill bacteria, as potential antimicrobial agents. Phage therapy in animal production, pets and experimental models of human infection have been discussed in veterinary medicine for 3 decades, with encouraging results in terms of reducing mortality, the severity of the clinical state and bacterial counts at tissue level. These benefits have been achieved thanks to increased knowledge of the biology of phages, better technology that allows their purification and their inherent advantages in terms of their safety for animals. Currently, phage research continues to open new horizons for both the medical industry and the food industry, considering the use of phages in the stages of "farm to fork", with promising results if used as an intervention in animals since their arrival to the slaughter house.

  15. The importance of the viable but non-culturable state in human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Laam eLi

    2014-06-01

    Full Text Available Many bacterial species have been found to exist in a viable but non-culturable (VBNC state since its discovery in 1982. VBNC cells are characterized by a loss of culturability on routine agar, which impairs their detection by conventional plate count techniques. This leads to an underestimation of total viable cells in environmental or clinical samples, and thus poses a risk to public health. In this review, we present recent findings on the VBNC state of human bacterial pathogens. The characteristics of VBNC cells, including the similarities and differences to viable, culturable cells and dead cells, and different detection methods are discussed. Exposure to various stresses can induce the VBNC state, and VBNC cells may be resuscitated back to culturable cells under suitable stimuli. The conditions that trigger the induction of the VBNC state and resuscitation from it are summarized and the mechanisms underlying these two processes are discussed. Last but not least, the significance of VBNC cells and their potential influence on human health are also reviewed.

  16. Analysis of pathogenic features of liver cirrhosis with spontaneous bacterial peritonitis

    Directory of Open Access Journals (Sweden)

    ZHANG Juling

    2015-03-01

    Full Text Available ObjectiveTo analyze the pathogenic and drug resistance features, as well as laboratory indices, of spontaneous bacterial peritonitis (SBP and to provide a basis for the early warning, rapid diagnosis, and timely treatment of the disease. MethodsThe clinical data and laboratory indices of 1340 patients diagnosed with SBP in 302 Hospital of PLA from January 2011 to December 2013 were retrospectively analyzed. The pathogenic spectrum and laboratory characteristics of SBP caused by different pathogenic bacteria were compared and the drug resistance features of the bacteria were also determined. Drug sensitivity results were analyzed with WHONET5 software, and statistical analysis was carried out with CHISS software. Comparison of continuous data was made by t test, and comparison of categorical data was made by chi-square test. ResultsOf the 1340 liver cirrhosis patients with SBP, 591 cases (44.10% were infected with gram-negative bacilli (G-b, 746 (55.67% with gram-positive cocci (G+C, one (0.07% with fungi, and two (0.15% with gram-positive bacilli(G+b. Compared with G+C infection, G-b infection involving other body parts had a significantly higher abnormality rate of laboratory indices including neutrophil, ascites white blood count (WBC, polymorphonuclear leukocyte (PMN, alanine aminotransferase (ALT, aspartate aminotransferase (AST, total bilirubin (TBil, exogenous prothrombin activity (PTA, and creatinine (Cr (P<0.05. The positive rates of extended-spectrum beta-lactamase (ESBL produced by Escherichia coli and Klebsiella pneumoniae were 40.00% and 36.03%, respectively. The drug resistance rates of Acinetobacter baumannii to amikacin, sulfamethoxazole/trimethoprim, and imipenem were 4242%, 5757%, and 5758%, respectively, while the drug resistance rates of Pseudomonas aeruginosa to cefoperazone and ticarcillin/clavulanic acid were 4545% and 3636%, respectively. The composition ratios of methicillin-resistant Staphylococcus

  17. Bacterial pathogen gene abundance and relation to recreational water quality at seven Great Lakes beaches.

    Science.gov (United States)

    Oster, Ryan J; Wijesinghe, Rasanthi U; Haack, Sheridan K; Fogarty, Lisa R; Tucker, Taaja R; Riley, Stephen C

    2014-12-16

    Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10 E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.

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

    Directory of Open Access Journals (Sweden)

    Lorraine P. Smith

    2011-01-01

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

  19. Viral and bacterial pathogens identification in children hospitalised for severe pneumonia and parapneumonic empyema

    Directory of Open Access Journals (Sweden)

    Jean-Noël Telles

    2012-05-01

    Full Text Available Pneumonia is caused by respiratory bacteria and/or viruses. Little is known if co-infections are an aggravating factor in hospitalised children with severe pneumonia. We studied the impact of respiratory pathogens on the severity of pneumonia. Between 2007 and 2009, 52 children hospitalised with a well-documented diagnosis of communityacquired pneumonia (CAP, with or without parapneumonic empyema (PPE, were enrolled in the study. The patients were classified into 2 groups: CAP + PPE (n = 28 and CAP (n = 24. The identification of respiratory viruses and bacteria in nasopharyngeal aspirates and pleural effusion samples were performed using conventional bacterial techniques and molecular assays. Using real-time multiplex PCR and antigen detection, Streptococcus pneumoniae was the main agent identified in 76% of the cases by molecular tests and BinaxNOW® in pleural fluid. A total of 8% of pleural fluid samples remained undiagnosed. In nasopharyngeal aspirates, rhinovirus, parainfluenza viruses, human metapneumovirus, and respiratory syncytial virus were detected in both CAP and CAP + PPE populations; however, the percentage of viral co-detection was significantly higher in nasopharyngeal aspirates from CAP + PPE patients (35% compared with CAP patients (5%. In conclusion, viral co-detection was observed mainly in patients with more severe pneumonia. Molecular biology assays improved the pathogens detection in pneumonia and confirmed the S. pneumoniae detection by BinaxNOW® in pleural effusion samples. Interestingly, the main S. pneumoniae serotypes found in PPE are not the ones targeted by the heptavalent pneumococcal conjugate vaccine.

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

    Directory of Open Access Journals (Sweden)

    Bhabesh Dutta

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

  1. Interactions of Seedborne Bacterial Pathogens with Host and Non-Host Plants in Relation to Seed Infestation and Seedling Transmission

    Science.gov (United States)

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

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1×106 colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized

  2. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens.

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R; Barany, Francis; Soper, Steven A

    2012-09-21

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft(3)). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic

  3. Bacterial pathogens and community composition in advanced sewage treatment systems revealed by metagenomics analysis based on high-throughput sequencing.

    Science.gov (United States)

    Lu, Xin; Zhang, Xu-Xiang; Wang, Zhu; Huang, Kailong; Wang, Yuan; Liang, Weigang; Tan, Yunfei; Liu, Bo; Tang, Junying

    2015-01-01

    This study used 454 pyrosequencing, Illumina high-throughput sequencing and metagenomic analysis to investigate bacterial pathogens and their potential virulence in a sewage treatment plant (STP) applying both conventional and advanced treatment processes. Pyrosequencing and Illumina sequencing consistently demonstrated that Arcobacter genus occupied over 43.42% of total abundance of potential pathogens in the STP. At species level, potential pathogens Arcobacter butzleri, Aeromonas hydrophila and Klebsiella pneumonia dominated in raw sewage, which was also confirmed by quantitative real time PCR. Illumina sequencing also revealed prevalence of various types of pathogenicity islands and virulence proteins in the STP. Most of the potential pathogens and virulence factors were eliminated in the STP, and the removal efficiency mainly depended on oxidation ditch. Compared with sand filtration, magnetic resin seemed to have higher removals in most of the potential pathogens and virulence factors. However, presence of the residual A. butzleri in the final effluent still deserves more concerns. The findings indicate that sewage acts as an important source of environmental pathogens, but STPs can effectively control their spread in the environment. Joint use of the high-throughput sequencing technologies is considered a reliable method for deep and comprehensive overview of environmental bacterial virulence.

  4. Bacterial pathogens and community composition in advanced sewage treatment systems revealed by metagenomics analysis based on high-throughput sequencing.

    Directory of Open Access Journals (Sweden)

    Xin Lu

    Full Text Available This study used 454 pyrosequencing, Illumina high-throughput sequencing and metagenomic analysis to investigate bacterial pathogens and their potential virulence in a sewage treatment plant (STP applying both conventional and advanced treatment processes. Pyrosequencing and Illumina sequencing consistently demonstrated that Arcobacter genus occupied over 43.42% of total abundance of potential pathogens in the STP. At species level, potential pathogens Arcobacter butzleri, Aeromonas hydrophila and Klebsiella pneumonia dominated in raw sewage, which was also confirmed by quantitative real time PCR. Illumina sequencing also revealed prevalence of various types of pathogenicity islands and virulence proteins in the STP. Most of the potential pathogens and virulence factors were eliminated in the STP, and the removal efficiency mainly depended on oxidation ditch. Compared with sand filtration, magnetic resin seemed to have higher removals in most of the potential pathogens and virulence factors. However, presence of the residual A. butzleri in the final effluent still deserves more concerns. The findings indicate that sewage acts as an important source of environmental pathogens, but STPs can effectively control their spread in the environment. Joint use of the high-throughput sequencing technologies is considered a reliable method for deep and comprehensive overview of environmental bacterial virulence.

  5. Bacteriophages with Potential for Inactivation of Fish Pathogenic Bacteria: Survival, Host Specificity and Effect on Bacterial Community Structure

    Directory of Open Access Journals (Sweden)

    Yolanda J. Silva

    2011-11-01

    Full Text Available Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

  6. Investigation of environmental drivers of antimicrobial resistance in foodborne bacterial pathogens in antibiotic-free, all natural, pastured poultry flocks.

    Science.gov (United States)

    Question: In the absence of antibiotic use within pastured poultry production, what are potential environmental variables that drive the antimicrobial sensitivity patterns of bacterial foodborne pathogens isolated from these flocks? Purpose: The objective of this study is to examine environmental f...

  7. Bacterial and viral pathogen spectra of acute respiratory infections in under-5 children in hospital settings in Dhaka city

    Science.gov (United States)

    Bhuyan, Golam Sarower; Hossain, Mohammad Amir; Sarker, Suprovath Kumar; Rahat, Asifuzzaman; Islam, Md Tarikul; Haque, Tanjina Noor; Begum, Noorjahan; Qadri, Syeda Kashfi; Muraduzzaman, A. K. M.; Islam, Nafisa Nawal; Islam, Mohammad Sazzadul; Sultana, Nusrat; Jony, Manjur Hossain Khan; Khanam, Farhana; Mowla, Golam; Matin, Abdul; Begum, Firoza; Shirin, Tahmina; Ahmed, Dilruba; Saha, Narayan; Qadri, Firdausi

    2017-01-01

    The study aimed to examine for the first time the spectra of viral and bacterial pathogens along with the antibiotic susceptibility of the isolated bacteria in under-5 children with acute respiratory infections (ARIs) in hospital settings of Dhaka, Bangladesh. Nasal swabs were collected from 200 under-five children hospitalized with clinical signs of ARIs. Nasal swabs from 30 asymptomatic children were also collected. Screening of viral pathogens targeted ten respiratory viruses using RT-qPCR. Bacterial pathogens were identified by bacteriological culture methods and antimicrobial susceptibility of the isolates was determined following CLSI guidelines. About 82.5% (n = 165) of specimens were positive for pathogens. Of 165 infected cases, 3% (n = 6) had only single bacterial pathogens, whereas 43.5% (n = 87) cases had only single viral pathogens. The remaining 36% (n = 72) cases had coinfections. In symptomatic cases, human rhinovirus was detected as the predominant virus (31.5%), followed by RSV (31%), HMPV (13%), HBoV (11%), HPIV-3 (10.5%), and adenovirus (7%). Streptococcus pneumoniae was the most frequently isolated bacterial pathogen (9%), whereas Klebsiella pneumaniae, Streptococcus spp., Enterobacter agglomerans, and Haemophilus influenzae were 5.5%, 5%, 2%, and 1.5%, respectively. Of 15 multidrug-resistant bacteria, a Klebsiella pneumoniae isolate and an Enterobacter agglomerans isolate exhibited resistance against more than 10 different antibiotics. Both ARI incidence and predominant pathogen detection rates were higher during post-monsoon and winter, peaking in September. Pathogen detection rates and coinfection incidence in less than 1-year group were significantly higher (P = 0.0034 and 0.049, respectively) than in 1–5 years age group. Pathogen detection rate (43%) in asymptomatic cases was significantly lower compared to symptomatic group (PStreptococcus pneumonia, and Klebsiella pneumaniae had significant involvement in coinfections with P values of

  8. A Bacterial Pathogen Displaying Temperature-Enhanced Virulence of the Microalga Emiliania huxleyi.

    Science.gov (United States)

    Mayers, Teaghan J; Bramucci, Anna R; Yakimovich, Kurt M; Case, Rebecca J

    2016-01-01

    shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate.

  9. Genetic Modulation of c-di-GMP Turnover Affects Multiple Virulence Traits and Bacterial Virulence in Rice Pathogen Dickeya zeae

    Science.gov (United States)

    Chen, Yufan; Lv, Mingfa; Liao, Lisheng; Gu, Yanfang; Liang, Zhibin; Shi, Zurong; Liu, Shiyin; Zhou, Jianuan; Zhang, Lianhui

    2016-01-01

    The frequent outbreaks of rice foot rot disease caused by Dickeya zeae have become a significant concern in rice planting regions and countries, but the regulatory mechanisms that govern the virulence of this important pathogen remain vague. Given that the second messenger cyclic di-GMP (c-di-GMP) is associated with modulation of various virulence-related traits in various microorganisms, here we set to investigate the role of the genes encoding c-di-GMP metabolism in the regulation of the bacterial physiology and virulence by construction all in-frame deletion mutants targeting the annotated c-di-GMP turnover genes in D. zeae strain EC1. Phenotype analyses identified individual mutants showing altered production of exoenzymes and phytotoxins, biofilm formation and bacterial motilities. The results provide useful clues and a valuable toolkit for further characterization and dissection of the regulatory complex that modulates the pathogenesis and persistence of this important bacterial pathogen. PMID:27855163

  10. Pathogen-induced conditioning of the primary xylem vessels - a prerequisite for the formation of bacterial emboli by Pectobacterium atrosepticum.

    Science.gov (United States)

    Gorshkov, V Y; Daminova, A G; Mikshina, P V; Petrova, O E; Ageeva, M V; Salnikov, V V; Gorshkova, T A; Gogolev, Y V

    2016-07-01

    Representatives of Pectobacterium genus are some of the most harmful phytopathogens in the world. In the present study, we have elucidated novel aspects of plant-Pectobacterium atrosepticum interactions. This bacterium was recently demonstrated to form specific 'multicellular' structures - bacterial emboli in the xylem vessels of infected plants. In our work, we showed that the process of formation of these structures includes the pathogen-induced reactions of the plant. The colonisation of the plant by P. atrosepticum is coupled with the release of a pectic polysaccharide, rhamnogalacturonan I, into the vessel lumen from the plant cell wall. This polysaccharide gives rise to a gel that serves as a matrix for bacterial emboli. P. atrosepticum-caused infection involves an increase of reactive oxygen species (ROS) levels in the vessels, creating the conditions for the scission of polysaccharides and modification of plant cell wall composition. Both the release of rhamnogalacturonan I and the increase in ROS precede colonisation of the vessels by bacteria and occur only in the primary xylem vessels, the same as the subsequent formation of bacterial emboli. Since the appearance of rhamnogalacturonan I and increase in ROS levels do not hamper the bacterial cells and form a basis for the assembly of bacterial emboli, these reactions may be regarded as part of the susceptible response of the plant. Bacterial emboli thus represent the products of host-pathogen integration, since the formation of these structures requires the action of both partners.

  11. The Water Cycle, a Potential Source of the Bacterial Pathogen Bacillus cereus

    Directory of Open Access Journals (Sweden)

    Julien Brillard

    2015-01-01

    Full Text Available The behaviour of the sporulating soil-dwelling Bacillus cereus sensu lato (B. cereus sl which includes foodborne pathogenic strains has been extensively studied in relation to its various animal hosts. The aim of this environmental study was to investigate the water compartments (rain and soil water, as well as groundwater closely linked to the primary B. cereus sl reservoir, for which available data are limited. B. cereus sl was present, primarily as spores, in all of the tested compartments of an agricultural site, including water from rain to groundwater through soil. During rain events, leachates collected after transfer through the soil eventually reached the groundwater and were loaded with B. cereus sl. In groundwater samples, newly introduced spores of a B. cereus model strain were able to germinate, and vegetative cells arising from this event were detected for up to 50 days. This first B. cereus sl investigation in the various types of interrelated environments suggests that the consideration of the aquatic compartment linked to soil and to climatic events should provide a better understanding of B. cereus sl ecology and thus be relevant for a more accurate risk assessment of food poisoning caused by B. cereus sl pathogenic strains.

  12. Developing an easy-to-apply model for identifying relevant pathogen pathways into surface waters used for recreational purposes.

    Science.gov (United States)

    Tondera, Katharina; Klaer, Kassandra; Roder, Silke; Brueckner, Ira; Strathmann, Martin; Kistemann, Thomas; Schreiber, Christiane; Pinnekamp, Johannes

    2016-10-01

    Swimming in inner-city surface waters is popular in the warm season, but can have negative consequences such as gastro-intestinal, ear and skin infections. The pathogens causing these infections commonly enter surface waters via several point source discharges such as the effluents from wastewater treatment plants and sewer overflows, as well as through diffuse non-point sources such as surface runoff. Nonetheless, the recreational use of surface waters is attractive for residents. In order to save financial and organizational resources, local authorities need to estimate the most relevant pathways of pathogens into surface waters. In particular, when detailed data on a local scale are missing, this is quite difficult to achieve. For this reason, we have developed an easy-to-apply model using the example of Escherichia coli and intestinal enterococci as a first approach to the local situation, where missing data can be replaced by data from literature. The model was developed based on a case study of a river arm monitored in western Germany and will be generalized for future applications. Although the limits of the EU Bathing Water Directive are already fulfilled during dry weather days, we showed that the effluent of wastewater treatment plants and overland flow had the most relevant impact on the microbial surface water quality. On rainy weather days, combined sewer overflows are responsible for the highest microbial pollution loads. The results obtained in this study can help decision makers to focus on reducing the relevant pathogen sources within a catchment area.

  13. Prevalence of Gram-negative Pathogens and their antimicrobial susceptibility in bacterial meningitis in pediatric cases

    Directory of Open Access Journals (Sweden)

    Yash Pal Chugh

    2012-07-01

    Full Text Available The present study was conducted to find out the prevalence and spectrum of Gram negative pathogens causing bacterial meningitis and their antimicrobial susceptibility pattern in a tertiary care hospital. The cerebrospinal fluid (CSF (3-5 ml was collected from 638 admitted children clinically suspected of septic meningitis. Bacterial isolates were identified and antimicrobial susceptibility was assessed by the Kirby-Bauer disk diffusion method. Of the 638 samples tested 102 (15.99% were culture positive. Male to female (M:F ratio was 1.62:1. The maximum incidence of 45 (44.12% cases was found in children (1-12 yrs; in institutional deliveries the incidence was 58 (56.86% cases. Further, the incidence of 51 cases was found from May to August. Escherichia coli (E. coli were commonest, seen in 9 (25% cases followed by Acinetobacter spp., Citrobacter spp. and Klebsiella spp. with 6 (16.67% cases each. Enterobacter spp., Neisseria spp. and Pseudomonas aeruginosa were isolated in 3 (8.33% cases each. E. coli, Acinetobacter spp, Citrobacter spp and Klebsiella spp isolates were 100% susceptible to meropenem, piperacillin-tazobactam and cefoperazone-sulbactam and 100% resistant to cotrimoxazole and tetracycline. All strains of Neisseria spp, Enterobacter spp and Pseudomonas spp. were 100% susceptible to meropenem followed by gatifloxacin. These were 100% resistant to tetracycline and cotrimoxazole. Neisseria spp. were also 100% susceptible to pristinamycin. In septic meningitis Gram negative organisms are less common (35.29%. Of the isolates, more common Gram negative isolates included E. coli, Acinetobacter Spp., Citrobacter Spp., and Klebsiella spp. and these isolates were 100% susceptible to meropenem, piperacillin-tazobacatam and cefoperazone-sulbactam. Hence, empirical therapy should be formulated according to antimicrobial susceptibility patterns.

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

    Directory of Open Access Journals (Sweden)

    Bocanegra-García Virgilio

    2009-06-01

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

  15. Screening of Lactobacillus strains of domestic goose origin against bacterial poultry pathogens for use as probiotics.

    Science.gov (United States)

    Dec, Marta; Puchalski, Andrzej; Urban-Chmiel, Renata; Wernicki, Andrzej

    2014-10-01

    Lactobacilli are natural inhabitants of human and animal mucous membranes, including the avian gastrointestinal tract. Recently, increasing attention has been given to their probiotic, health-promoting capacities, among which their antagonistic potential against pathogens plays a key role. A study was conducted to evaluate probiotic properties of Lactobacillus strains isolated from feces or cloacae of domestic geese. Among the 104 examined isolates, previously identified to the species level by whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and analysis of 16S-23S regions of rDNA, dominated Lactobacillus salivarius (35%), followed by Lactobacillus johnsonii (18%) and Lactobacillus ingluviei (11%). All lactobacilli were screened for antimicrobial activity toward Salmonella Enteritidis, Escherichia coli, Clostridium perfringens, Staphylococcus aureus, Pasteurella multocida, and Riemerella anatipestifer using the agar slab method and the well diffusion method. Lactobacillus salivarius and Lactobacillus plantarum exhibited particularly strong antagonism toward all of the indicator strains. In the agar slab method, the highest sensitivity to Lactobacillus was observed in R. anatipestifer and P. multocida, and the lowest in E. coli and S. aureus. The ability to produce H₂O₂was exhibited by 92% of isolates, but there was no correlation between the rate of production of this reactive oxygen species and the antimicrobial activity of Lactobacillus sp. All lactobacilli showed resistance to pH 3.0 and 3.5 and to 2% bile. The data demonstrate that Lactobacillus isolates from geese may have probiotic potential in reducing bacterial infections. The antibacterial activity of the selected lactobacilli is mainly due to lactic acid production by these bacteria. The selected Lactobacillus strains that strongly inhibited the growth of pathogenic bacteria, and were also resistant to low pH and bile salts, can potentially restore the balance

  16. [Pathogenic potential of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, the red bacterial complex associated with periodontitis].

    Science.gov (United States)

    Bodet, C; Chandad, F; Grenier, D

    2007-01-01

    Periodontitis are mixed bacterial infections leading to destruction of tooth-supporting tissues, including periodontal ligament and alveolar bone. Among over 500 bacterial species living in the oral cavity, a bacterial complex named "red complex" and made of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia has been strongly related to advanced periodontal lesions. While periodontopathogenic bacteria are the primary etiologic factor of periodontitis, tissue destruction essentially results from the host immune response to the bacterial challenge. Members of the red complex are Gram negative anaerobic bacteria expressing numerous virulence factors allowing bacteria to colonize the subgingival sites, to disturb the host defense system, to invade and destroy periodontal tissue as well as to promote the immunodestructive host response. This article reviews current knowledge of the pathogenic mechanisms of bacteria of the red complex leading to tissue and alveolar bone destruction observed during periodontitis.

  17. Comparative Genomic and Phenotypic Characterization of Pathogenic and Non-Pathogenic Strains of Xanthomonas arboricola Reveals Insights into the Infection Process of Bacterial Spot Disease of Stone Fruits.

    Science.gov (United States)

    Garita-Cambronero, Jerson; Palacio-Bielsa, Ana; López, María M; Cubero, Jaime

    2016-01-01

    Xanthomonas arboricola pv. pruni is the causal agent of bacterial spot disease of stone fruits, a quarantinable pathogen in several areas worldwide, including the European Union. In order to develop efficient control methods for this disease, it is necessary to improve the understanding of the key determinants associated with host restriction, colonization and the development of pathogenesis. After an initial characterization, by multilocus sequence analysis, of 15 strains of X. arboricola isolated from Prunus, one strain did not group into the pathovar pruni or into other pathovars of this species and therefore it was identified and defined as a X. arboricola pv. pruni look-a-like. This non-pathogenic strain and two typical strains of X. arboricola pv. pruni were selected for a whole genome and phenotype comparative analysis in features associated with the pathogenesis process in Xanthomonas. Comparative analysis among these bacterial strains isolated from Prunus spp. and the inclusion of 15 publicly available genome sequences from other pathogenic and non-pathogenic strains of X. arboricola revealed variations in the phenotype associated with variations in the profiles of TonB-dependent transporters, sensors of the two-component regulatory system, methyl accepting chemotaxis proteins, components of the flagella and the type IV pilus, as well as in the repertoire of cell-wall degrading enzymes and the components of the type III secretion system and related effectors. These variations provide a global overview of those mechanisms that could be associated with the development of bacterial spot disease. Additionally, it pointed out some features that might influence the host specificity and the variable virulence observed in X. arboricola.

  18. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

    Directory of Open Access Journals (Sweden)

    Mari Narusaka

    Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.

  19. Ixodes ricinus and its transmitted pathogens in urban and peri-urban areas in Europe: new hazards and relevance for public health

    Directory of Open Access Journals (Sweden)

    Annapaola eRizzoli

    2014-12-01

    Full Text Available Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium sized mammals, birds, companion animals (dogs, cats and larger mammals (roe deer, wild boar play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, 'Candidatus Neoehrlichia mikurensis', Rickettsia helvetica, R. monacensis, Borrelia miyamatoi and protozoans (Babesia divergens, B. venatorum and B. microti have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.

  20. Cultivation and qPCR Detection of Pathogenic and Antibiotic-Resistant Bacterial Establishment in Naive Broiler Houses.

    Science.gov (United States)

    Brooks, J P; McLaughlin, M R; Adeli, A; Miles, D M

    2016-05-01

    Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space for approximately 6.5 wk. This environment is known for harboring pathogens and antibiotic-resistant bacteria, but studies have focused on previously established houses with mature litter microbial populations. In the current study, a set of three naive houses were followed from inception through 11 broiler flocks and monitored for ambient climatic conditions, bacterial pathogens, and antibiotic resistance. Within the first 3 wk of the first flock cycle, 100% of litter samples were positive for and , whereas was cultivation negative but PCR positive. Antibiotic resistance genes were ubiquitously distributed throughout the litter within the first flock, approaching 10 to 10 genomic units g. Preflock litter levels were approximately 10 CFU g for heterotrophic plate count bacteria, whereas midflock levels were >10 colony forming units (CFU) g; other indicators demonstrated similar increases. The influence of intrahouse sample location was minor. In all likelihood, given that preflock levels were negative for pathogens and antibiotic resistance genes and 4 to 5 Log lower than flock levels for indicators, incoming birds most likely provided the colonizing microbiome, although other sources were not ruled out. Most bacterial groups experienced a cyclical pattern of litter contamination seen in other studies, whereas microbial stabilization required approximately four flocks. This study represents a first-of-its-kind view into the time required for bacterial pathogens and antibiotic resistance to colonize and establish in naive broiler houses.

  1. Zoonotic vector-borne bacterial pathogens in California mountain lions (Puma concolor), 1987-2010.

    Science.gov (United States)

    Girard, Yvette A; Swift, Pamela; Chomel, Bruno B; Kasten, Rickie W; Fleer, Katryna; Foley, Janet E; Torres, Steven G; Johnson, Christine K

    2012-11-01

    Sera collected from 442 mountain lions in 48 California counties between the years of 1987 and 2010 were tested using immunofluorescence assays and agglutination tests for the presence of antibodies reactive to Yersinia pestis, Francisella tularensis, Bartonella henselae, Borrelia burgdorferi, and Anaplasma phagocytophilum antigens. Data were analyzed for spatial and temporal trends in seropositivity. Seroprevalences for B. burgdorferi (19.9%) and B. henselae (37.1%) were relatively high, with the highest exposure in the Central Coast region for B. henselae. B. henselae DNA amplified in mountain lion samples was genetically similar to human-derived Houston-1 and domestic cat-derived U4 B. henselae strains at the gltA and ftsZ loci. The statewide seroprevalences of Y. pestis (1.4%), F. tularensis (1.4%), and A. phagocytophilum (5.9%), were comparatively low. Sera from Y. pestis- and F. tularensis-seropositive mountain lions were primarily collected in the Eastern and Western Sierra Nevada, and samples reactive to Y. pestis antigen were collected exclusively from adult females. Adult age (≥ 2 years) was a risk factor for B. burgdorferi exposure. Over 70% of tested animals were killed on depredation permits, and therefore were active near areas with livestock and human residential communities. Surveillance of mountain lions for these bacterial vector-borne and zoonotic agents may be informative to public health authorities, and the data are useful for detecting enzootic and peridomestic pathogen transmission patterns, particularly in combination with molecular characterization of the infecting organisms.

  2. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

    Institute of Scientific and Technical Information of China (English)

    Rabia Naz; Asghari Bano

    2012-01-01

    Objective: To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Methods:Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Results:Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. Conclusions: The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  3. Microfluidic system for the identification of bacterial pathogens causing urinary tract infections

    Science.gov (United States)

    Becker, Holger; Hlawatsch, Nadine; Haraldsson, Tommy; van der Wijngaart, Wouter; Lind, Anders; Malhotra-Kumar, Surbi; Turlej-Rogacka, Agata; Goossens, Herman

    2015-03-01

    Urinary tract infections (UTIs) are among the most common bacterial infections and pose a significant healthcare burden. The growing trend in antibiotic resistance makes it mandatory to develop diagnostic kits which allow not only the determination of a pathogen but also the antibiotic resistances. We have developed a microfluidic cartridge which takes a direct urine sample, extracts the DNA, performs an amplification using batch-PCR and flows the sample over a microarray which is printed into a microchannel for fluorescence detection. The cartridge is injection-molded out of COP and contains a set of two-component injection-molded rotary valves to switch between input and to isolate the PCR chamber during thermocycling. The hybridization probes were spotted directly onto a functionalized section of the outlet microchannel. We have been able to successfully perform PCR of E.coli in urine in this chip and perform a fluorescence detection of PCR products. An upgraded design of the cartridge contains the buffers and reagents in blisters stored on the chip.

  4.   Bloodstream Bacterial Pathogens and their Antibiotic Resistance Pattern in Dhahira Region, Oman

    Directory of Open Access Journals (Sweden)

    PP Geethanjali

    2011-07-01

    Full Text Available Objectives: To describe the epidemiological, clinical, microbiological characteristics and antimicrobial resistance pattern of Bloodstream infections in Dhahira region, Oman.Methods: Clinical data was collected from all patients with positive blood cultures for two years period. Standard laboratory methods were used for blood culture. Antibiotic sensitivity was tested using Kirby-Bauer disc diffusion method.Results: Of the 360 bacterial pathogens isolated from 348 patients, 57.8�0were gram-positive and 42.2�0were gram-negative. The common isolates were: Streptococcus species 76 (21.1� coagulase-negative Staphylococci 75 (20.8� Escherichia coli 43 (11.9� Staphylococcus aureus 41 (11.4� Overall, mortality was 21.3�0(74/348. Staphylococcus species (Staphylococcus aureus and CoNS were more commonly resistant to Trimethoprim/ Sulphamethoxazole (35.3�20and Penicillin (25.9� Streptococcus species were resistant to Trimethoprim/Sulphamethoxazole (39.1�20and Erythromycin (19.6�Conclusion: Bloodstream infections are important causes of morbidity and mortality in our patients, especially among chronically ill elderly adult males. Prescription of proven resistant antibiotics to suspected bacteremic patients needs attention in Dhahira region.

  5. Evaluation of a multiplex PCR for bacterial pathogens applied to bronchoalveolar lavage.

    Science.gov (United States)

    Strålin, K; Korsgaard, J; Olcén, P

    2006-09-01

    The present study assessed the diagnostic usefulness of a multiplex PCR (mPCR) for Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae and Chlamydophila pneumoniae applied to bronchoalveolar lavage (BAL). Fibreoptic bronchoscopy was performed on 156 hospitalised adult patients with lower respiratory tract infection (LRTI) and 36 controls. BAL fluid was analysed with bacterial culture and mPCR. By conventional diagnostic methods, S. pneumoniae, H. influenzae, M. pneumoniae and C. pneumoniae were aetiological agents in 14, 21, 3.2 and 0% of the LRTI patients, respectively. These pathogens were identified by BAL mPCR in 28, 47, 3.2 and 0.6% of cases, respectively, yielding sensitivities of 86% for S. pneumoniae, 88% for H. influenzae, 100% for M. pneumoniae and 0% for C. pneumoniae, and specificities of 81, 64, 100 and 99% for S. pneumoniae, H. influenzae, M. pneumoniae and C. pneumoniae, respectively. Of the 103 patients who had taken antibiotics prior to bronchoscopy, S. pneumoniae was identified by culture in 2.9% and by mPCR in 31%. Among the controls, mPCR identified S. pneumoniae in 11% and H. influenzae in 39%. In lower respiratory tract infection patients, bronchoalveolar lavage multiplex PCR can be useful for identification of Streptococcus pneumoniae, Mycoplasma pneumoniae and Chlamydophila pneumoniae. The method appears to be particularly useful in patients treated with antibiotics.

  6. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains.

    Science.gov (United States)

    Naz, Rabia; Bano, Asghari

    2012-12-01

    To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  7. Susceptibility of conjunctival bacterial pathogens to fluoroquinolones. A comparative study of ciprofloxacin, norfloxacin and ofloxacin

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    Stella Odjimogho

    2003-10-01

    Full Text Available In order to determine the most common bacteria implicated in conjunctivitis, and the effectiveness of the antibiotic Fluoroquinolone for its treatment, a total of 50 subjects (100 eyes, between the ages of 1-30 years with mean age of 16.94 ± 8.06 years with infected eyes, were examined at the Lagos State University Teaching Hospital, Nigeria (LASUTH. Conjunctival swabs were collected and cultured in the laboratory to isolate the pathogens responsible for the infection. Sensitivity and antibiotic suscepticibility tests were carried out with discs impregnated with 0.3% concentration of ophthalmic topical solutions of chibroxin (Norfloxacin, ciloxan (Ciprofloxacin, and ocuflox (Ofloxacin, to ascertain the most sensitive of the three drugs. The results showed that the implicated bacteria in order of decreasing frequency were Staphylococcus aureus (34%, followed by Streptococcus pneumoniae (22%, Pseudomonas aeruginosa (14%, Klebsiella pneumoniae (12%, Hemophilus influenzae (9%, Escherichia coli (9%. All the isolated organisms were highly sensitive to the three drugs. However, a one way analysis of variance (ANOVA showed a significant difference in the sensitivity of the three drugs (p< 0.05. ANOVA Post Hoc located Ciprofloxacin as the source of the significance. In conclusion therefore, Ciprofloxacin is the most sensitive of the three drugs and, hence should be the first choice of the fluoroquinolones for the treatment of bacterial conjunctivitis.

  8. Genomic Analysis of Clavibacter michiganensis Reveals Insight Into Virulence Strategies and Genetic Diversity of a Gram-Positive Bacterial Pathogen.

    Science.gov (United States)

    Thapa, Shree P; Pattathil, Sivakumar; Hahn, Michael G; Jacques, Marie-Agnès; Gilbertson, Robert L; Coaker, Gitta

    2017-10-01

    Clavibacter michiganensis subsp. michiganensis is a gram-positive bacterial pathogen that proliferates in the xylem vessels of tomato, causing bacterial canker disease. In this study, we sequenced and assembled genomes of 11 C. michiganensis subsp. michiganensis strains isolated from infected tomato fields in California as well as five Clavibacter strains that colonize tomato endophytically but are not pathogenic in this host. The analysis of the C. michiganensis subsp. michiganensis genomes supported the monophyletic nature of this pathogen but revealed genetic diversity among strains, consistent with multiple introduction events. Two tomato endophytes that clustered phylogenetically with C. michiganensis strains capable of infecting wheat and pepper and were also able to cause disease in these plants. Plasmid profiles of the California strains were variable and supported the essential role of the pCM1-like plasmid and the CelA cellulase in virulence, whereas the absence of the pCM2-like plasmid in some pathogenic C. michiganensis subsp. michiganensis strains revealed it is not essential. A large number of secreted C. michiganensis subsp. michiganensis proteins were carbohydrate-active enzymes (CAZymes). Glycome profiling revealed that C. michiganensis subsp. michiganensis but not endophytic Clavibacter strains is able to extensively alter tomato cell-wall composition. Two secreted CAZymes found in all C. michiganensis subsp. michiganensis strains, CelA and PelA1, enhanced pathogenicity on tomato. Collectively, these results provide a deeper understanding of C. michiganensis subsp. michiganensis diversity and virulence strategies.

  9. Deciphering the role of coumarin as a novel quorum sensing inhibitor suppressing virulence phenotypes in bacterial pathogens.

    Science.gov (United States)

    Gutiérrez-Barranquero, José A; Reen, F Jerry; McCarthy, Ronan R; O'Gara, Fergal

    2015-04-01

    The rapid unchecked rise in antibiotic resistance over the last few decades has led to an increased focus on the need for alternative therapeutic strategies for the treatment and clinical management of microbial infections. In particular, small molecules that can suppress microbial virulence systems independent of any impact on growth are receiving increased attention. Quorum sensing (QS) is a cell-to-cell signalling communication system that controls the virulence behaviour of a broad spectrum of bacterial pathogens. QS systems have been proposed as an effective target, particularly as they control biofilm formation in pathogens, a key driver of antibiotic ineffectiveness. In this study, we identified coumarin, a natural plant phenolic compound, as a novel QS inhibitor, with potent anti-virulence activity in a broad spectrum of pathogens. Using a range of biosensor systems, coumarin was active against short, medium and long chain N-acyl-homoserine lactones, independent of any effect on growth. To determine if this suppression was linked to anti-virulence activity, key virulence systems were studied in the nosocomial pathogen Pseudomonas aeruginosa. Consistent with suppression of QS, coumarin inhibited biofilm, the production of phenazines and swarming motility in this organism potentially linked to reduced expression of the rhlI and pqsA quorum sensing genes. Furthermore, coumarin significantly inhibited biofilm formation and protease activity in other bacterial pathogens and inhibited bioluminescence in Aliivibrio fischeri. In light of these findings, coumarin would appear to have potential as a novel quorum sensing inhibitor with a broad spectrum of action.

  10. The bacterial pathogen Listeria monocytogenes and the interferon family: type I, type II and type III interferons

    Directory of Open Access Journals (Sweden)

    Olivier eDussurget

    2014-04-01

    Full Text Available Interferons (IFNs are secreted proteins of the cytokine family that regulate innate and adaptive immune responses to infection. Although the importance of IFNs in the antiviral response has long been appreciated, their role in bacterial infections is more complex and is currently a major focus of investigation. This review summarizes our current knowledge of the role of these cytokines in host defense against the bacterial pathogen Listeria monocytogenes and highlights recent discoveries on the molecular mechanisms evolved by this intracellular bacterium to subvert IFN responses.

  11. The bacterial pathogen Listeria monocytogenes and the interferon family: type I, type II and type III interferons.

    Science.gov (United States)

    Dussurget, Olivier; Bierne, Hélène; Cossart, Pascale

    2014-01-01

    Interferons (IFNs) are secreted proteins of the cytokine family that regulate innate and adaptive immune responses to infection. Although the importance of IFNs in the antiviral response has long been appreciated, their role in bacterial infections is more complex and is currently a major focus of investigation. This review summarizes our current knowledge of the role of these cytokines in host defense against the bacterial pathogen Listeria monocytogenes and highlights recent discoveries on the molecular mechanisms evolved by this intracellular bacterium to subvert IFN responses.

  12. Structured literature review of responses of cattle to viral and bacterial pathogens causing bovine respiratory disease complex.

    Science.gov (United States)

    Grissett, G P; White, B J; Larson, R L

    2015-01-01

    Bovine respiratory disease (BRD) is an economically important disease of cattle and continues to be an intensely studied topic. However, literature summarizing the time between pathogen exposure and clinical signs, shedding, and seroconversion is minimal. A structured literature review of the published literature was performed to determine cattle responses (time from pathogen exposure to clinical signs, shedding, and seroconversion) in challenge models using common BRD viral and bacterial pathogens. After review a descriptive analysis of published studies using common BRD pathogen challenge studies was performed. Inclusion criteria were single pathogen challenge studies with no treatment or vaccination evaluating outcomes of interest: clinical signs, shedding, and seroconversion. Pathogens of interest included: bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BHV-1), parainfluenza-3 virus, bovine respiratory syncytial virus, Mannheimia haemolytica, Mycoplasma bovis, Pastuerella multocida, and Histophilus somni. Thirty-five studies and 64 trials were included for analysis. The median days to the resolution of clinical signs after BVDV challenge was 15 and shedding was not detected on day 12 postchallenge. Resolution of BHV-1 shedding resolved on day 12 and clinical signs on day 12 postchallenge. Bovine respiratory syncytial virus ceased shedding on day 9 and median time to resolution of clinical signs was on day 12 postchallenge. M. haemolytica resolved clinical signs 8 days postchallenge. This literature review and descriptive analysis can serve as a resource to assist in designing challenge model studies and potentially aid in estimation of duration of clinical disease and shedding after natural pathogen exposure.

  13. Evidence of the presence of a functional Dot/Icm type IV-B secretion system in the fish bacterial pathogen Piscirickettsia salmonis.

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    Fernando A Gómez

    Full Text Available Piscirickettsia salmonis is a fish bacterial pathogen that has severely challenged the sustainability of the Chilean salmon industry since its appearance in 1989. As this Gram-negative bacterium has been poorly characterized, relevant aspects of its life cycle, virulence and pathogenesis must be identified in order to properly design prophylactic procedures. This report provides evidence of the functional presence in P. salmonis of four genes homologous to those described for Dot/Icm Type IV Secretion Systems. The Dot/Icm System, the major virulence mechanism of phylogenetically related pathogens Legionella pneumophila and Coxiella burnetii, is responsible for their intracellular survival and multiplication, conditions that may also apply to P. salmonis. Our results demonstrate that the four P. salmonis dot/icm homologues (dotB, dotA, icmK and icmE are expressed both during in vitro tissue culture cells infection and growing in cell-free media, suggestive of their putative constitutive expression. Additionally, as it happens in other referential bacterial systems, temporal acidification of cell-free media results in over expression of all four P. salmonis genes, a well-known strategy by which SSTIV-containing bacteria inhibit phagosome-lysosome fusion to survive. These findings are very important to understand the virulence mechanisms of P. salmonis in order to design new prophylactic alternatives to control the disease.

  14. The Antibacterial Activity of Acetic Acid against Biofilm-Producing Pathogens of Relevance to Burns Patients.

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    Fenella D Halstead

    Full Text Available Localised infections, and burn wound sepsis are key concerns in the treatment of burns patients, and prevention of colonisation largely relies on biocides. Acetic acid has been shown to have good antibacterial activity against various planktonic organisms, however data is limited on efficacy, and few studies have been performed on biofilms.We sought to investigate the antibacterial activity of acetic acid against important burn wound colonising organisms growing planktonically and as biofilms.Laboratory experiments were performed to test the ability of acetic acid to inhibit growth of pathogens, inhibit the formation of biofilms, and eradicate pre-formed biofilms.Twenty-nine isolates of common wound-infecting pathogens were tested. Acetic acid was antibacterial against planktonic growth, with an minimum inhibitory concentration of 0.16-0.31% for all isolates, and was also able to prevent formation of biofilms (at 0.31%. Eradication of mature biofilms was observed for all isolates after three hours of exposure.This study provides evidence that acetic acid can inhibit growth of key burn wound pathogens when used at very dilute concentrations. Owing to current concerns of the reducing efficacy of systemic antibiotics, this novel biocide application offers great promise as a cheap and effective measure to treat infections in burns patients.

  15. Altering the thermal resistance of foodborne bacterial pathogens with an eggshell membrane waste by-product.

    Science.gov (United States)

    Poland, A L; Sheldon, B W

    2001-04-01

    Eggshells from egg-breaking operations are a significant waste disposal problem. Thus, the development of value-added by-products from this waste would be welcomed by the industry. The ability of extracted eggshell membranes containing, several bacteriolytic enzymes (i.e., lysozyme and beta-N-acetylglucosaminidase) or other membrane components to alter the thermal resistance of gram-positive and gram-negative bacterial pathogens was evaluated. Mid-log phase cells of Salmonella Enteritidis (SE), Salmonella Typhimurium (ST), Escherichia coli O157:H7 (EC), Listeria monocytogenes Scott A (LM), and Staphylococcus aureus (SA) were suspended in 100 ml of 0.1% peptone water (pH 6.9, 10(7-8) CFU/ml) containing either 0 (control) or 10 g of an eggshell membrane extract and incubated at 37 degrees C for 45 min. Following exposure, membrane-free samples (1.5 ml) were heated in a 56 degrees C (LM, SA), 54 degrees C (SE, ST), or 52 degrees C (EC) water bath from 0 to 14 min in sealed glass reaction vials (12 by 32 mm), and the survivors were recovered on brain heart infusion agar. Population reductions ranging from 27.6% (SA) to 99.8% (LM) (ST, 43.8%; SE, 47.5%; EC, 71.8%) were observed for cells treated for 45 min with extracted membrane, as compared to controls. D-value reductions ranging from 0 (LM) to 87.2% (SE) (SA, 36.7%; EC, 83.3%; ST, 86.3%) were observed when membrane-treated cells were subsequently heat inactivated. The effects of exposure pH, time, temperature, and organic load on membrane activity were also evaluated with Salmonella Typhimurium. Exposure pH (5.0 versus 6.9), time (15 versus 45 min), and temperature (4 degrees C versus 37 degrees C) did not significantly reduce the impact of eggshell membranes on D-values. However, the presence of organic matter (0.1% peptone water versus skim milk) significantly reduced the thermal resistance-reducing capacity of the membranes. These preliminary findings provide information on the potential use of extracted eggshell

  16. Nano-layered magnesium fluoride reservoirs on biomaterial surfaces strengthen polymorphonuclear leukocyte resistance to bacterial pathogens.

    Science.gov (United States)

    Guo, Geyong; Zhou, Huaijuan; Wang, Qiaojie; Wang, Jiaxing; Tan, Jiaqi; Li, Jinhua; Jin, Ping; Shen, Hao

    2017-01-05

    Biomaterial-related bacterial infections cause patient suffering, mortality and extended periods of hospitalization, imposing a substantial burden on medical systems. In this context, understanding of nanomaterials-bacteria-cells interactions is of both fundamental and clinical significance. Herein, nano-MgF2 films were deposited on titanium substrate via magnetron sputtering. Using this platform, the antibacterial behavior and mechanism of the nano-MgF2 films were investigated in vitro and in vivo. It was found that, for S. aureus (CA-MRSA, USA300) and S. epidermidis (RP62A), the nano-MgF2 films possessed excellent anti-biofilm activity, but poor anti-planktonic bacteria activity in vitro. Nevertheless, both the traditional SD rat osteomyelitis model and the novel stably luminescent mouse infection model demonstrated that nano-MgF2 films exerted superior anti-infection effect in vivo, which cannot be completely explained by the antibacterial activity of the nanomaterial itself. Further, using polymorphonuclear leukocytes (PMNs), the critical immune cells of innate immunity, a complementary investigation of MgF2-bacteria-PMNs co-culturing revealed that the nano-MgF2 films improved the antibacterial effect of PMNs through enhancing their phagocytosis and stability. To our knowledge, this is the first time of exploring the antimicrobial mechanism of nano-MgF2 from the perspective of innate immunity both in vitro and in vivo. Based on the research results, a plausible mechanism is put forward for the predominant antibacterial effect of nano-MgF2in vivo, which may originate from the indirect immune enhancement effect of nano-MgF2 films. In summary, this study of surface antibacterial design using MgF2 nanolayer is a meaningful attempt, which can promote the host innate immune response to bacterial pathogens. This may give us a new understanding towards the antibacterial behavior and mechanism of nano-MgF2 films and pave the way towards their clinical applications.

  17. Prevalence of MDR pathogens of bacterial meningitis in Egypt and new synergistic antibiotic combinations

    Science.gov (United States)

    Abdelkader, Mona M.; Aboshanab, Khaled M.; El-Ashry, Marwa A.; Aboulwafa, Mohammad M.

    2017-01-01

    The aim of this study was identifying bacterial pathogens involved in meningitis, studying their antibiotic resistance profiles, investigating the antibiotic resistance genes as well as evaluating the use of various antibiotic combinations. Antibiotic susceptibility tests were evaluated according to CLSI guidelines. Antibiotic combinations were evaluated by calculating the Fractional Inhibitory Concentration (FIC) index. A total of 71 bacterial isolates were recovered from 68 culture positive CSF specimens. Sixty five of these isolates (91.5%) were recovered from single infection specimens, while 6 isolates (8.4%) were recovered from mixed infection specimens. Out of the 71 recovered isolates, 48 (67.6%) were Gram-positive, and 23 (32.4%) were Gram-negative. Thirty one of the Gram positive isolates were S. pneumoniae (64.6%, n = 48). Out of the recovered 71 isolates; 26 (36.6%) were multidrug-resistant (MDR) isolates of which, 18 (69.2%) were Gram-negative and 8 (30.8%) were Gram-positive. All MDR isolates (100%) showed resistance to penicillin and ampicillin, however, they showed lower resistance to meropenem (50%), levofloxacin (50%), amikacin (48%), pipercillin-tazobactam (45.8%). Most common antibiotic resistance genes were investigated including: tem (21.1%), shv (15.8%), ctx-m (15.8%) coding for TEM-, SHV, CTX-M extended-spectrum beta-lactamases (ESBLs), respectively; aac(6')-I b(26.3%) coding for aminoglycoside 6’-N-acetyltransferase type Ib ciprofloxacin resistant variant; and qnrA (5.3%) gene coding for quinolone resistance. The DNA sequences of the respective resistance genes of some selected isolates were PCR amplified, analyzed and submitted to the GenBank database under the accession numbers, KX214665, KX214664, KX214663, KX214662, respectively. The FIC values for ampicillin/sulbactam plus cefepime showed either additive or synergistic effect against ten tested Gram-negative MDR isolates, while doxycycline plus levofloxacin combination revealed

  18. Enteric bacterial pathogens in children with diarrhea in Niger: diversity and antimicrobial resistance.

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    Céline Langendorf

    Full Text Available Although rotavirus is the leading cause of severe diarrhea among children in sub-Saharan Africa, better knowledge of circulating enteric pathogenic bacteria and their antimicrobial resistance is crucial for prevention and treatment strategies.As a part of rotavirus gastroenteritis surveillance in Maradi, Niger, we performed stool culture on a sub-population of children under 5 with moderate-to-severe diarrhea between April 2010 and March 2012. Campylobacter, Shigella and Salmonella were sought with conventional culture and biochemical methods. Shigella and Salmonella were serotyped by slide agglutination. Enteropathogenic Escherichia coli (EPEC were screened by slide agglutination with EPEC O-typing antisera and confirmed by detection of virulence genes. Antimicrobial susceptibility was determined by disk diffusion. We enrolled 4020 children, including 230 with bloody diarrhea. At least one pathogenic bacterium was found in 28.0% of children with watery diarrhea and 42.2% with bloody diarrhea. Mixed infections were found in 10.3% of children. EPEC, Salmonella and Campylobacter spp. were similarly frequent in children with watery diarrhea (11.1%, 9.2% and 11.4% respectively and Shigella spp. were the most frequent among children with bloody diarrhea (22.1%. The most frequent Shigella serogroup was S. flexneri (69/122, 56.5%. The most frequent Salmonella serotypes were Typhimurimum (71/355, 20.0%, Enteritidis (56/355, 15.8% and Corvallis (46/355, 13.0%. The majority of putative EPEC isolates was confirmed to be EPEC (90/111, 81.1%. More than half of all Enterobacteriaceae were resistant to amoxicillin and co-trimoxazole. Around 13% (46/360 Salmonella exhibited an extended-spectrum beta-lactamase phenotype.This study provides updated information on enteric bacteria diversity and antibiotic resistance in the Sahel region, where such data are scarce. Whether they are or not the causative agent of diarrhea, bacterial infections and their antibiotic

  19. Clinical outcomes with besifloxacin ophthalmic suspension 0.6% in the treatment of bacterial conjunctivitis due to potentially consequential pathogens

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    Comstock TL

    2014-04-01

    Full Text Available Timothy L Comstock,1 Timothy W Morris,2 Lynne S Gearinger,2 Heleen H DeCory11Medical Affairs, 2Department of Microbiology and Sterilization Sciences, Bausch + Lomb, Rochester, NY, USAPurpose: Besifloxacin is a chlorofluoroquinolone approved for use in the treatment of bacterial conjunctivitis. This study assessed the clinical efficacy of besifloxacin ophthalmic suspension 0.6% against conjunctivitis infections caused by potentially consequential pathogens.Design: Post hoc analysis of clinical outcomes for patients with conjunctival infections due to Pseudomonas aeruginosa, Serratia marcescens, Neisseria spp., methicillin-resistant Staphylococcus aureus (MRSA, and methicillin-resistant Staphylococcus epidermidis (MRSE who were treated with besifloxacin in four multicenter, double-masked, randomized clinical trials.Methods: Minimum inhibitory concentrations (MICs of besifloxacin against potentially consequential pathogens were pooled. Clinical outcome data for patients treated with besifloxacin with baseline infections due to these pathogens were pooled and summarized. Bacterial eradication was defined as the absence of ocular bacterial species present at or above threshold at baseline.Results: A total of 1,317 patients had culture-confirmed bacterial conjunctivitis across the four studies, and 151 infections were due to the aforementioned pathogens (P. aeruginosa n=9; S. marcescens n=10; Neisseria spp. n=16; MRSA n=35; MRSE n=81. Among MRSA and MRSE infections, 48.3% demonstrated concurrent ciprofloxacin resistance (ciprofloxacin-resistant [CipR]-MRSA n=24; CipR-MRSE n=32. The MIC90 (MIC for 90% of isolates for besifloxacin was 1 µg/mL for S. marcescens, 0.25 µg/mL for Neisseria spp., 0.06 µg/mL for both ciprofloxacin-sensitive MRSA and ciprofloxacin-sensitive MRSE, and 4 µg/mL for both CipR-MRSA and CipR-MRSE. Against P. aeruginosa, the MIC range was 1–4 µg/mL. Bacterial eradication rates in patients treated with besifloxacin were 100% by

  20. Capsaicin-sensitive vagal afferent neurons contribute to the detection of pathogenic bacterial colonization in the gut

    OpenAIRE

    2013-01-01

    Vagal activation can reduce inflammation and disease activity in various animal models of intestinal inflammation via the cholinergic anti-inflammatory pathway. In the current model of this pathway, activation of descending vagal efferents is dependent on a signal initiated by stimulation of vagal afferents. However, little is known about how vagal afferents are activated, especially in the context of subclinical or clinical pathogenic bacterial infection. To address this question, we first d...

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

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    Reshmi eUpreti

    2015-04-01

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

  2. Arabidopsis Clade I TGA Factors Regulate Apoplastic Defences against the Bacterial Pathogen Pseudomonas syringae through Endoplasmic Reticulum-Based Processes

    OpenAIRE

    Lipu Wang; Pierre R Fobert

    2013-01-01

    During the plant immune response, large-scale transcriptional reprogramming is modulated by numerous transcription (co) factors. The Arabidopsis basic leucine zipper transcription factors TGA1 and TGA4, which comprise the clade I TGA factors, have been shown to positively contribute to disease resistance against virulent strains of the bacterial pathogen Pseudomonas syringae . Despite physically interacting with the key immune regulator, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), f...

  3. Removal of Contaminant DNA by Combined UV-EMA Treatment Allows Low Copy Number Detection of Clinically Relevant Bacteria Using Pan-Bacterial Real-Time PCR.

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    Bruce Humphrey

    Full Text Available More than two decades after its discovery, contaminant microbial DNA in PCR reagents continues to impact the sensitivity and integrity of broad-range PCR diagnostic techniques. This is particularly relevant to their use in the setting of human sepsis, where a successful diagnostic on blood samples needs to combine universal bacterial detection with sensitivity to 1-2 genome copies, because low levels of a broad range of bacteria are implicated.We investigated the efficacy of ethidium monoazide (EMA and propidium monoazide (PMA treatment as emerging methods for the decontamination of PCR reagents. Both treatments were able to inactivate contaminating microbial DNA but only at concentrations that considerably affected assay sensitivity. Increasing amplicon length improved EMA/PMA decontamination efficiency but at the cost of assay sensitivity. The same was true for UV exposure as an alternative decontamination strategy, likely due to damage sustained by oligonucleotide primers which were a significant source of contamination. However, a simple combination strategy with UV-treated PCR reagents paired with EMA-treated primers produced an assay capable of two genome copy detection and a <5% contamination rate. This decontamination strategy could have important utility in developing improved pan-bacterial assays for rapid diagnosis of low pathogen burden conditions such as in the blood of patients with suspected blood stream infection.

  4. Target-specific capture enhances sensitivity of electrochemical detection of bacterial pathogens.

    Science.gov (United States)

    Patel, Mayank; Gonzalez, Rodrigo; Halford, Colin; Lewinski, Michael A; Landaw, Elliot M; Churchill, Bernard M; Haake, David A

    2011-12-01

    We report the concentration and purification of bacterial 16S rRNA by the use of a biotinylated DNA target-specific capture (TSC) probe. For both cultivated bacterial and urine specimens from urinary tract infection patients, TSC resulted in a 5- to 8-fold improvement in the sensitivity of bacterial detection in a 16S rRNA electrochemical sensor assay.

  5. In vitro antibacterial activity of venom protein isolated from sea snake Enhydrina schistosa against drugresistant human pathogenic bacterial strains

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    Palani Damotharan

    2015-06-01

    Full Text Available Objective: To evaluate the antibacterial activity of sea snake (Enhydrina schistosa venom protein against drug-resistant human pathogenic bacterial strains. Methods: The venom was collected by milking process from the live specimens of sea snake are using capillary tubes or glass plates. Venom was purified by ion exchange chromatography and it was tested for in-vitro antibacterial activity against 10 drug-resistant human pathogenic bacterial strains using the standard disc diffusion method. Results: The notable antibacterial activity was observed at 150 µg/mL concentration of purified venom and gave its minimum inhibitory concentrations values exhibited between 200-100 µg/mL against all the tested bacterial strains. The maximum zone of inhibition was observed at 16.4 mm against Salmonella boydii and the minimum activity was observed at 7.5 mm against Pseudomonas aeruginosa. After the sodium-dodecyl-sulfate-polyacrylamide gel electrophoresis there were a clear single band was detected in the gel that corresponding to purified venom protein molecular weight of 44 kDa. Conclusions: These results suggested that the sea snake venom might be a feasible source for searching potential antibiotics agents against human pathogenic diseases.

  6. One-day workflow scheme for bacterial pathogen detection and antimicrobial resistance testing from blood cultures.

    Science.gov (United States)

    Hansen, Wendy L J; Beuving, Judith; Verbon, Annelies; Wolffs, Petra F G

    2012-07-09

    Bloodstream infections are associated with high mortality rates because of the probable manifestation of sepsis, severe sepsis and septic shock(1). Therefore, rapid administration of adequate antibiotic therapy is of foremost importance in the treatment of bloodstream infections. The critical element in this process is timing, heavily dependent on the results of bacterial identification and antibiotic susceptibility testing. Both of these parameters are routinely obtained by culture-based testing, which is time-consuming and takes on average 24-48 hours(2, 4). The aim of the study was to develop DNA-based assays for rapid identification of bloodstream infections, as well as rapid antimicrobial susceptibility testing. The first assay is a eubacterial 16S rDNA-based real-time PCR assay complemented with species- or genus-specific probes(5). Using these probes, Gram-negative bacteria including Pseudomonas spp., Pseudomonas aeruginosa and Escherichia coli as well as Gram-positive bacteria including Staphylococcus spp., Staphylococcus aureus, Enterococcus spp., Streptococcus spp., and Streptococcus pneumoniae could be distinguished. Using this multiprobe assay, a first identification of the causative micro-organism was given after 2 h. Secondly, we developed a semi-molecular assay for antibiotic susceptibility testing of S. aureus, Enterococcus spp. and (facultative) aerobe Gram-negative rods(6). This assay was based on a study in which PCR was used to measure the growth of bacteria(7). Bacteria harvested directly from blood cultures are incubated for 6 h with a selection of antibiotics, and following a Sybr Green-based real-time PCR assay determines inhibition of growth. The combination of these two methods could direct the choice of a suitable antibiotic therapy on the same day (Figure 1). In conclusion, molecular analysis of both identification and antibiotic susceptibility offers a faster alternative for pathogen detection and could improve the diagnosis of

  7. Rapid detection and identification of bacterial pathogens by using an ATP bioluminescence immunoassay.

    Science.gov (United States)

    Hunter, Dawn M; Lim, Daniel V

    2010-04-01

    Rapid identification of viable bacterial contaminants in food products is important because of their potential to cause disease. This study examined a method for microbial detection by using a combined ATP bioluminescence immunoassay. Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium were selected as target organisms because of their implication in foodborne illness. Various matrices containing the target cells were examined, including ground beef homogenate, apple juice, milk, and phosphate-buffered saline. Specific antibodies were immobilized on the surface of 96-well plates, and then the sample matrices containing target cells in the wells were incubated. Sample matrix (no cells) was used to establish background. The plates were washed, and the wells were incubated with BacTiter-Glo reagent in Mueller-Hinton II broth. Bioluminescent output was measured with the GloMax 96 luminometer. Signal-to-noise ratios were calculated, resulting in a limit of detection of 10(4) CFU/ml for both E. coli O157:H7 and Salmonella Typhimurium. The limit of detection for both species was not affected by the presence of nontarget cells. The various sample matrices did not affect signal-to-noise ratios when E. coli O157:H7 was the target. A weak matrix effect was observed when Salmonella Typhimurium was the target. A strong linear correlation was observed between the number of cells and luminescent output over 4 orders of magnitude for both species. This method provides a means of simultaneously detecting and identifying viable pathogens in complex matrices, and could have wider application in food microbiology.

  8. Prophage-mediated dynamics of 'Candidatus Liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.

    Directory of Open Access Journals (Sweden)

    Lijuan Zhou

    Full Text Available Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB, a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and

  9. Bacterial pathogens and their antimicrobial susceptibility in Otukpo Benue state of Nigeria

    Institute of Scientific and Technical Information of China (English)

    Okwori EE; Nwadioha SI; Nwokedi EOP; Odimayo M; Jombo GTA

    2011-01-01

    Objective:To isolate bacterial pathogens and test for their antibiotic susceptibility. Methods:A total of 20 000 samples from 9 different clinical sites were processed in the laboratory between 1987 to 2000. The specimens were inoculated on the appropriate media for the isolation of the bacteria. Biochemical and serology tests were carried out on the organisms to confirm the type of bacteria isolated. Antibiotic susceptibility test was also carried out on each of the bacteria isolated. Results:A total of 18 520 bacteria were isolated from the specimens. The specimens were from nine different clinical sites, i.e. wound accounted for 22.84%, urine 31.67%, blood 12.38%, genital 7.70%, sputum 6.81%, stool 6.28%, cerebrospinal fluid 5.98%, aspirates 3.85%and ear/throat swabs were 2.49%. Gram negative bacteria accounted for 76%of isolates. The main species were Pseudomonas 2 238 (12.08%), Escherichia coli (E. coli) 2 073 (11.19%) and Staphylococcus aureus (S. aureus) which accounted for 2 511 (13.56%) of the total isolates. S. aureus showed 70%and 65%resistance to penicillin and ampicillin, respectively. Surprisingly, 40%of the organism was resistant to cloxacillin. E. coli showed 47%and 42%resistance to ampicillin and gentamicin, respectively. 49%of Salmonella typhi was resistant to chloramphenicol while 37%of Neisseria meningitidis was resistant to penicillin. Conclusions: The rate of bacteria isolated from the clinical specimens is high and antibiotic sensitivity pattern of the organisms vary from one antibiotic to the other.

  10. Iron Limitation Triggers Early Egress by the Intracellular Bacterial Pathogen Legionella pneumophila

    Science.gov (United States)

    Zheng, Huaixin; VanRheenen, Susan M.; Ghosh, Soma; Cianciotto, Nicholas P.; Isberg, Ralph R.

    2016-01-01

    Legionella pneumophila is an intracellular bacterial pathogen that replicates in alveolar macrophages, causing a severe form of pneumonia. Intracellular growth of the bacterium depends on its ability to sequester iron from the host cell. In the L. pneumophila strain 130b, one mechanism used to acquire this essential nutrient is the siderophore legiobactin. Iron-bound legiobactin is imported by the transport protein LbtU. Here, we describe the role of LbtP, a paralog of LbtU, in iron acquisition in the L. pneumophila strain Philadelphia-1. Similar to LbtU, LbtP is a siderophore transport protein and is required for robust growth under iron-limiting conditions. Despite their similar functions, however, LbtU and LbtP do not contribute equally to iron acquisition. The Philadelphia-1 strain lacking LbtP is more sensitive to iron deprivation in vitro. Moreover, LbtP is important for L. pneumophila growth within macrophages while LbtU is dispensable. These results demonstrate that LbtP plays a dominant role over LbtU in iron acquisition. In contrast, loss of both LbtP and LbtU does not impair L. pneumophila growth in the amoebal host Acanthamoeba castellanii, demonstrating a host-specific requirement for the activities of these two transporters in iron acquisition. The growth defect of the ΔlbtP mutant in macrophages is not due to alterations in growth kinetics. Instead, the absence of LbtP limits L. pneumophila replication and causes bacteria to prematurely exit the host cell. These results demonstrate the existence of a preprogrammed exit strategy in response to iron limitation that allows L. pneumophila to abandon the host cell when nutrients are exhausted. PMID:27185787

  11. Prophage-mediated dynamics of 'Candidatus Liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.

    Science.gov (United States)

    Zhou, Lijuan; Powell, Charles A; Li, Wenbin; Irey, Mike; Duan, Yongping

    2013-01-01

    Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and disease development.

  12. Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators

    Science.gov (United States)

    Haack, S.K.; Duris, J.W.; Fogarty, L.R.; Kolpin, D.W.; Focazio, M.J.; Furlong, E.T.; Meyer, M.T.

    2009-01-01

    The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes. Genes tested included esp (indicating human-pathogenic ENT) and nine genes associated with various animal sources of shiga-toxin-producing EC (STEC). Fecal pollution was indicated by genes and/or chemicals for 14 of the 18 tested samples, with little relation to FIB standards. Of 13 samples with 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.

  13. In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Muhammad Kamruzzaman; S.M. Nayeemul Bari; Shah M. Faruque

    2013-01-01

    Objective: To investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens. Methods: Water and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). Results: Methanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9-22.6 mm, MIC:200-3 200 μg/mL, MBC: 200-6 400 μg/mL) against all the pathogenic enteric bacteria (Vibriocholerae , Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001). Conclusions: For the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

  14. A membrane-bound matrix-metalloproteinase from Nicotiana tabacum cv. BY-2 is induced by bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Wahner Verena

    2009-06-01

    Full Text Available Abstract Background Plant matrix metalloproteinases (MMP are conserved proteolytic enzymes found in a wide range of monocotyledonous and dicotyledonous plant species. Acting on the plant extracellular matrix, they play crucial roles in many aspects of plant physiology including growth, development and the response to stresses such as pathogen attack. Results We have identified the first tobacco MMP, designated NtMMP1, and have isolated the corresponding cDNA sequence from the tobacco suspension cell line BY-2. The overall domain structure of NtMMP1 is similar to known MMP sequences, although certain features suggest it may be constitutively active rather than dependent on proteolytic processing. The protein appears to be expressed in two forms with different molecular masses, both of which are enzymatically active as determined by casein zymography. Exchanging the catalytic domain of NtMMP1 with green fluorescent protein (GFP facilitated subcellular localization by confocal laser scanning microscopy, showing the protein is normally inserted into the plasma membrane. The NtMMP1 gene is expressed constitutively at a low level but can be induced by exposure to bacterial pathogens. Conclusion Our biochemical analysis of NtMMP1 together with bioinformatic data on the primary sequence indicate that NtMMP1 is a constitutively-active protease. Given its induction in response to bacterial pathogens and its localization in the plasma membrane, we propose a role in pathogen defense at the cell periphery.

  15. Immunity induced shortly after DNA vaccination of rainbow trout against rhabdoviruses protects against heterologous virus but not against bacterial pathogens

    DEFF Research Database (Denmark)

    Lorenzen, Niels; Lorenzen, Ellen; Einer-Jensen, Katja;

    2002-01-01

    It was recently reported that DNA vaccination of rainbow trout fingerlings against viral hemorrhagic septicaemia virus (VHSV) induced protection within 8 days after intramuscular injection of plasmid DNA. In order to analyse the specificity of this early immunity, fish were vaccinated with plasmid...... DNA encoding the VHSV or the infectious haematopoietic necrosis virus (IHNV) glycoprotein genes and later challenged with homologous or heterologous pathogens. Challenge experiments revealed that immunity established shortly after vaccination was cross-protective between the two viral pathogens...... whereas no increased survival was found upon challenge with bacterial pathogens. Within two months after vaccination, the cross-protection disappeared while the specific immunity to homologous virus remained high. The early immunity induced by the DNA vaccines thus appeared to involve short-lived non...

  16. Antibacterial efficacy of the seed extracts of Melia azedarach against some hospital isolated human pathogenic bacterial strains

    Institute of Scientific and Technical Information of China (English)

    Abdul Viqar Khan; Qamar Uddin Ahmed; M Ramzan Mir; Indu Shukla; Athar Ali Khan

    2011-01-01

    To investigate the antibacterial potential of the polar and non-polar extracts of the seeds of Melia azedarach (M. azedarach) L. (Meliaceae) against eighteen hospital isolated human pathogenic bacterial strains. Methods: Petrol, benzene, ethyl acetate, methanol, and aqueous extracts at five different concentrations (1, 2, 5, 10 and 15 mg/mL) were evaluated. Disk diffusion method was followed to evaluate the antibacterial efficacy. Results: All extracts of the seeds demonstrated significant antibacterial activity against tested pathogens. Among all extracts, ethyl acetate extract revealed the highest inhibition comparatively. The present study also favored the traditional uses reported earlier. Conclusions: Results of this study strongly confirm that the seed extracts of M. azedarach could be effective antibiotics, both in controlling gram-positive and gram-negative human pathogenic infections.

  17. Antibiotic resistance among bacterial pathogens in Central Africa: a review of the published literature between 1955 and 2008.

    Science.gov (United States)

    Vlieghe, E; Phoba, M F; Tamfun, J J Muyembe; Jacobs, J

    2009-10-01

    A systematic review of the published literature on bacterial resistance in Central Africa between 1955 and 2008 was performed. Eighty-three publications from seven countries were retrieved, the majority presenting data on enteric and other gram-negative pathogens. Despite methodological limitations in many studies, alarming resistance rates are noted in nearly all pathogens. Of special concern are multidrug resistance in Shigella and Salmonella spp. and the emergence of meticillin-resistant Staphylococcus aureus, high-level penicillin-resistant Streptococcus pneumoniae and extended-spectrum beta-lactamases among gram-negative pathogens. These findings make clear that the Central African region shares the worldwide trend of increasing antimicrobial resistance and is in urgent need of sound surveillance based on competent and affordable microbiology to provide clear data on antimicrobial resistance. These data could enable redaction of local treatment guidelines and fuel national and regional policies to contain antimicrobial resistance.

  18. Influence of phenolic compounds of Kangra tea [Camellia sinensis (L O Kuntze] on bacterial pathogens and indigenous bacterial probiotics of Western Himalayas

    Directory of Open Access Journals (Sweden)

    Aditi Sourabh

    2013-09-01

    Full Text Available Phenolic compounds of nutraceutical importance viz., catechins (C, (--epicatechin (EC, (--epigallocatechin (EGC, (--epigallocatechin-3-gallate (EGCG and (--epicatechin-3-gallate (ECG were estimated in fresh green tea shoots of Camellia sinensis (L O Kuntze cultivar. The total polyphenols and total catechins were in the range of 219.90 to 317.81 and 140.83 to 271.39 g/kg, respectively in monthly samples of tea. The values of C, EC, EGC, EGCG and ECG in tea powders as analyzed through high performance liquid chromatography (HPLC were in the range of 1.560 to 3.661, 13.338 to 27.766, 26.515 to 39.597, 62.903 to 102.168 and 18.969 to 39.469 mg/g, respectively. Effect of tea extracts and standard flavanols against five pathogenic bacteria viz., Listeria monocytogenes (MTCC-839, Pseudomonas aeruginosa (MTCC-741, Bacillus cereus (MTCC-1272, Staphylococcus aureus (MTCC-96 and Escherichia coli (MTCC-443, and eleven indigenous potential bacterial probiotics belonging to genera Enterococcus, Bacillus and Lactobacillus spp. obtained from fermented foods of Western Himalayas, was investigated. EGCG, ECG and EGC exhibited antibacterial activity but, C and EC did not show this activity. Tea extracts having high concentrations of EGCG and ECG were more potent in antibacterial action against bacterial pathogens. Tea extracts and standard flavan-3-ols augmented viability of potential probiotics in an order of EGCG > EGC > ECG > EC > C. Tea extracts and standard flavanols had no antibacterial activity against Escherichia coli (MTCC-443 but, in combination with probiotic culture supernatants, this activity was seen. The Kangra tea thus, exerts antibacterial effect on bacterial pathogens through EGCG, ECG and EGC constituents while stimulatory effect on growth of indigenous potential probiotics.

  19. Co-Selection of Resistance to Antibiotics, Biocides and Heavy Metals, and Its Relevance to Foodborne Pathogens

    Directory of Open Access Journals (Sweden)

    Andrew D. Wales

    2015-11-01

    Full Text Available Concerns have been raised in recent years regarding co-selection for antibiotic resistance among bacteria exposed to biocides used as disinfectants, antiseptics and preservatives, and to heavy metals (particularly copper and zinc used as growth promoters and therapeutic agents for some livestock species. There is indeed experimental and observational evidence that exposure to these non-antibiotic antimicrobial agents can induce or select for bacterial adaptations that result in decreased susceptibility to one or more antibiotics. This may occur via cellular mechanisms that are protective across multiple classes of antimicrobial agents or by selection of genetic determinants for resistance to non-antibiotic agents that are linked to genes for antibiotic resistance. There may also be relevant effects of these antimicrobial agents on bacterial community structure and via non-specific mechanisms such as mobilization of genetic elements or mutagenesis. Notably, some co-selective adaptations have adverse effects on fitness in the absence of a continued selective pressure. The present review examines the evidence for the significance of these phenomena, particularly in respect of bacterial zoonotic agents that commonly occur in livestock and that may be transmitted, directly or via the food chain, to human populations.

  20. Microarray-based identification of clinically relevant vaginal bacteria in relation to bacterial vaginosis

    NARCIS (Netherlands)

    Dols, J.A.M.; Smit, P.W.; Kort, R.; Reid, G.; Schuren, F.H.J.; Tempelman, H.; Bontekoe, T.R.; Korporaal, H.; Boon, M.E.

    2011-01-01

    Objective: The objective was to examine the use of a tailor-made DNA microarray containing probes representing the vaginal microbiota to examine bacterial vaginosis. Study Design: One hundred one women attending a health center for HIV testing in South Africa were enrolled. Stained, liquid-based

  1. Microarray-based identification of clinically relevant vaginal bacteria in relation to bacterial vaginosis

    NARCIS (Netherlands)

    Dols, J.A.M.; Smit, P.W.; Kort, R.; Reid, G.; Schuren, F.H.J.; Tempelman, H.; Bontekoe, T.R.; Korporaal, H.; Boon, M.E.

    2011-01-01

    Objective: The objective was to examine the use of a tailor-made DNA microarray containing probes representing the vaginal microbiota to examine bacterial vaginosis. Study Design: One hundred one women attending a health center for HIV testing in South Africa were enrolled. Stained, liquid-based cyt

  2. Raman spectroscopy based toolkit for mapping bacterial social interactions relevant to human and plant health

    Science.gov (United States)

    Couvillion, Sheha Polisetti

    Bacteria interact and co-exist with other microbes and with higher organisms like plants and humans, playing a major role in their health and well being. These ubiquitous single celled organisms are so successful, because they can form organized communities, called biofilms, that protect them from environmental stressors and enable communication and cooperation among members of the community. The work described in this thesis develops a toolkit of analytical techniques centered around Raman microspectroscopy and imaging representing a powerful approach to non-invasively investigate bacterial communities, yielding molecular information at the sub-micrometer length scale. Bacterial cellular components of non-pigmented and pigmented rhizosphere strains are characterized, and regiospecific SERS is used for cases where resonantly enhanced background signals obscure the spectra. Silver nanoparticle colloids were synthesized in situ, in the presence of the cells to form a proximal coating and principal component analysis (PCA) revealed features attributed to flavins. SERS enabled in situ acquisition of Raman spectra and chemical images in highly autofluorescent P.aeruginosa biofilms. In combination with PCA, this allowed for non-invasive spatial mapping of bacterial communities and revealed differences between strains and nutrients in the secretion of virulence factor pyocyanin. The rich potential of using Raman microspectroscopy to study plant-microbe interactions is demonstrated. Effect of exposure to oxidative stress, on both the wild type Pantoea sp. YR343 and carotenoid mutant Delta crtB, was assessed by following the intensity of the 1520 cm -1 and 1126 cm-1 Raman bands, respectively, after treatment with various concentrations of H2O2. Significant changes were observed in these marker bands even at concentrations (1 mM) below the point at which the traditional plate-based viability assay shows an effect (5-10 mM), thus establishing the value of Raman

  3. Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Rajinder S Mann

    Full Text Available Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las, affects host preference behavior of its psyllid (Diaphorina citri Kuwayama vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of

  4. Frontiers for research on the ecology of plant-pathogenic bacteria: fundamentals for sustainability: Challenges in Bacterial Molecular Plant Pathology.

    Science.gov (United States)

    Morris, Cindy E; Barny, Marie-Anne; Berge, Odile; Kinkel, Linda L; Lacroix, Christelle

    2017-02-01

    Methods to ensure the health of crops owe their efficacy to the extent to which we understand the ecology and biology of environmental microorganisms and the conditions under which their interactions with plants lead to losses in crop quality or yield. However, in the pursuit of this knowledge, notions of the ecology of plant-pathogenic microorganisms have been reduced to a plant-centric and agro-centric focus. With increasing global change, i.e. changes that encompass not only climate, but also biodiversity, the geographical distribution of biomes, human demographic and socio-economic adaptations and land use, new plant health problems will emerge via a range of processes influenced by these changes. Hence, knowledge of the ecology of plant pathogens will play an increasingly important role in the anticipation and response to disease emergence. Here, we present our opinion on the major challenges facing the study of the ecology of plant-pathogenic bacteria. We argue that the discovery of markedly novel insights into the ecology of plant-pathogenic bacteria is most likely to happen within a framework of more extensive scales of space, time and biotic interactions than those that currently guide much of the research on these bacteria. This will set a context that is more propitious for the discovery of unsuspected drivers of the survival and diversification of plant-pathogenic bacteria and of the factors most critical for disease emergence, and will set the foundation for new approaches to the sustainable management of plant health. We describe the contextual background of, justification for and specific research questions with regard to the following challenges: Development of terminology to describe plant-bacterial relationships in terms of bacterial fitness. Definition of the full scope of the environments in which plant-pathogenic bacteria reside or survive. Delineation of pertinent phylogenetic contours of plant-pathogenic bacteria and naming of strains

  5. Finding immune gene expression differences induced by marine bacterial pathogens in the Deep-sea hydrothermal vent mussel Bathymodiolus azoricus

    Science.gov (United States)

    Martins, E.; Queiroz, A.; Serrão Santos, R.; Bettencourt, R.

    2013-11-01

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus lives in a natural environment characterised by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea vent biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in vent animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio bacteria. Flavobacterium suspensions were also used as a non-pathogenic bacterium. Gene expression analyses were carried out using gill samples from infected animals by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h to 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the bacterium inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly evident for proteins of 18-20 KDa molecular mass, where most dissimilarity was found. Multivariate analyses demonstrated that immune genes, as well as experimental

  6. A Study of Parasitic and Bacterial Pathogens Associated with Diarrhea in HIV-Positive Patients

    Science.gov (United States)

    Kongre, Vaishali; Kumar, Varun; Bharadwaj, Renu

    2016-01-01

    Introduction Diarrhea is a common complication of acquired immune deficiency syndrome (AIDS), occurring in almost 90% of AIDS patients in developing countries like India. The present study was aimed to determine the prevalence and microbiological profile of pathogens associated with diarrhea in human immunodeficiency virus (HIV) positive patients and their relation to CD4 counts. Materials and methods Forty-five successive HIV-positive patients, 27 with diarrhea (study group) and 18 without diarrhea (control group), were included in the three-month study. The HIV infection was confirmed by three different antibody detection tests. The stool samples were collected on two consecutive days and were examined for parasites by microscopy using wet mount and modified Ziehl-Neelsen stain. They were examined for bacteria by Gram stain and conventional Ziehl-Neelsen stain and were inoculated on appropriate culture media. The isolates were identified by standard biochemical tests, followed by antibiotic susceptibility testing using the Kirby-Bauer disc diffusion method. Results  Twenty-four pathogens were detected in diarrheal HIV-positive patients, including 14 parasites (58.33%), seven bacteria (29.17%), and three fungi (12.50%). Isospora sp. was the most common parasite (25.9%) followed by Cryptosporidium sp. (14.8%). Other parasites included Cyclospora sp., Strongyloides stercoralis, and Entamoeba histolytica (3.7% each).​ Escherichia coli (18.5%) was the most common bacterial isolate, of which, 80% were Enterotoxigenic E. coli (ETEC) while 20% were Enteropathogenic E. coli (EPEC). Other isolates included Shigella flexneri and Mycobacterium tuberculosis (3.7% each). The isolates were sensitive to furazolidone (94.11%), chloramphenicol (76.47%), and gentamicin (52.94%). The isolates from diarrheal patients showed resistance to norfloxacin (5.88% vs. 50%, p<0.05) as compared to those from non-diarrheal patients. The diarrheal HIV-positive patients

  7. Anti-biotic Effect of Slightly Acidic Electrolyzed Water on Plant Bacterial / Fungal Pathogen

    OpenAIRE

    津野, 和宣; 中村, 悌一

    2012-01-01

    The anti-biotic effect of slightly acidic electrolyzed water on plant pathogen was determined. The spores of 4 kinds of fungal pathogen and 17 kinds of plant pathogenic bacteria were applied at different concentration.###Slightly acidic electrolyzed water showed strong growth inhibition in germination of fungi spores tested. In addition, by the treatment with slightly acidic electrolyzed water for 30 sec., all kinds of bacteria tested were inhibited to grow on the medium.###The anti-biotic ef...

  8. Incidence and clinical relevance of bacterial contamination in preservation solution for liver transplantation.

    Science.gov (United States)

    Ruiz, P; Gastaca, M; Gonzalez, J; Hernandez, M J; Ventoso, A; Valdivieso, A; Montejo, M; Ortiz de Urbina, J

    2009-01-01

    Postoperative infection is considered one of the most important causes of morbidity and mortality after liver transplantation. We prospectively studied the incidence and significance of infections in preservation solutions for liver transplantation. From March 2007 to March 2008, we cultured the University of Wisconsin preservation solution for 60 consecutive liver transplantations. Fluid samples were obtained at the beginning and at the end of the back table procedure. Our posttransplant infection prophylactic protocol consisted of ampicillin and cefotaxime for 48 hours. Cultures were positive in 59 patients (98.4%). Seventy-five percent of the isolates were superficial saprophytic flora (SSF; Staphylococcus coagulase negative, Streptococcus viridans, and Corynebacterium), nevertheless in 15 cases (25.1%) we isolated high virulence pathogens (Staphylococcus aureus, Klebsiella, Escherichia coli, Enterobacter, and Pseudomonas aeruginosa). There were neither anaerobic nor fungal isolates. Sixteen patients (36%) from the group with SSF developed postoperative fever, including 12 with negative posttransplant cultures, while 4 patients showed positive cultures for various microorganisms distinct from those isolated from the preservation solution. Five patients (30%) with high virulence pathogens in the preservation solution developed posttransplant fever, although no pathogen was isolated. Positive cultures of preservation fluids were observed in 98% of patients, although most of them (75%) were SSF. Microorganisms isolated from posttransplant cultures did not match the ones obtained from the preservation solution. Our results did not support routine culturing of the preservation solution provided that one administrator an adequate posttransplant antibiotic prophylactic regimen.

  9. ``Black Holes" and Bacterial Pathogenicity: A Large Genomic Deletion that Enhances the Virulence of Shigella spp. and Enteroinvasive Escherichia coli

    Science.gov (United States)

    Maurelli, Anthony T.; Fernandez, Reinaldo E.; Bloch, Craig A.; Rode, Christopher K.; Fasano, Alessio

    1998-03-01

    Plasmids, bacteriophages, and pathogenicity islands are genomic additions that contribute to the evolution of bacterial pathogens. For example, Shigella spp., the causative agents of bacillary dysentery, differ from the closely related commensal Escherichia coli in the presence of a plasmid in Shigella that encodes virulence functions. However, pathogenic bacteria also may lack properties that are characteristic of nonpathogens. Lysine decarboxylate (LDC) activity is present in ≈ 90% of E. coli strains but is uniformly absent in Shigella strains. When the gene for LDC, cadA, was introduced into Shigella flexneri 2a, virulence became attenuated, and enterotoxin activity was inhibited greatly. The enterotoxin inhibitor was identified as cadaverine, a product of the reaction catalyzed by LDC. Comparison of the S. flexneri 2a and laboratory E. coli K-12 genomes in the region of cadA revealed a large deletion in Shigella. Representative strains of Shigella spp. and enteroinvasive E. coli displayed similar deletions of cadA. Our results suggest that, as Shigella spp. evolved from E. coli to become pathogens, they not only acquired virulence genes on a plasmid but also shed genes via deletions. The formation of these ``black holes,'' deletions of genes that are detrimental to a pathogenic lifestyle, provides an evolutionary pathway that enables a pathogen to enhance virulence. Furthermore, the demonstration that cadaverine can inhibit enterotoxin activity may lead to more general models about toxin activity or entry into cells and suggests an avenue for antitoxin therapy. Thus, understanding the role of black holes in pathogen evolution may yield clues to new treatments of infectious diseases.

  10. Mycobacterium biofilms: factors involved in development, dispersal, and therapeutic strategies against biofilm-relevant pathogens.

    Science.gov (United States)

    Xiang, Xiaohong; Deng, Wanyan; Liu, Minqiang; Xie, Jianping

    2014-01-01

    Many bacteria can develop biofilm (BF), a multicellular structure largely combining bacteria and their extracellular polymeric substances (EPS). The formation of biofilm results in an alternative existence in which microbes ensure their survival in adverse environments. Biofilm-relevant infections are more persistent, resistant to most antibiotics, and more recalcitrant to host immunity. Mycobacterium tuberculosis, the causative agent of tuberculosis, can develop biofilm, though whether M. tuberculosis can form biofilm within tuberculosis patients has yet to be determined. Here, we summarize the factors involved in the development and dispersal of mycobacterial biofilms, as well as underlying regulatory factors and inhibitors against biofilm to deepen our understanding of their development and to elucidate potential novel modes of action for future antibiotics. Key factors in biofilm formation identified as drug targets represent a novel and promising avenue for developing better antibiotics.

  11. Diagnosis of bacterial pathogens in the dialysate of peritoneal dialysis patients with peritonitis using surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Tien, Ni; Chen, Hung-Chih; Gau, Shiow-Lan; Lin, Tzu-Hsien; Lin, Hsiu-Shen; You, Bang-Jau; Tsai, Po-Chuan; Chen, I-Ru; Tsai, Ming-Fan; Wang, I-Kuan; Chen, Chao-Jung; Chang, Chiz-Tzung

    2016-10-01

    Bacterial peritonitis is the most common cause of peritoneal dialysis (PD) therapy drop-out. A quick and accurate diagnosis of the bacterial pathogen can reduce the PD drop-out rate. Surface-enhanced Raman spectroscopy (SERS) can rapidly identify bacteria using chips coated with nano-sized metal particles. Known bacteria were loaded in the SERS-chips and illuminated with laser light to establish a reference Raman spectra library. Dialysate from PD peritonitis patients was concentrated by centrifuge and examined with the same SERS, and the resulting Raman spectra were compared with library spectra for bacteria identification. Principal component analysis was used for further confirmation. The same batches of dialysate were sent to routine culture as a reference bacteria identification method. The results of the 2 identification methods were compared. A total of 43 paired-samples were sent for study. There were 37 samples with bacteria identified but 6 were culture-negative by the reference method. 31 bacteria were identified in paired-samples by SERS, among which, 29 bacteria were exactly the same as those identified by the reference method. Bacteria not included in the reference library spectra cannot be identified. SERS techniques can rapidly identify bacterial pathogens in the dialysate of PD peritonitis patients. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Antibacterial activity of carbapenems against clinical isolates of respiratory bacterial pathogens in the northeastern region of Japan in 2007.

    Science.gov (United States)

    Gomi, Kazunori; Fujimura, Shigeru; Fuse, Katsuhiro; Takane, Hidenari; Nakano, Yoshihisa; Kariya, Yasuko; Kikuchi, Toshiaki; Kurokawa, Iku; Tokue, Yutaka; Watanabe, Akira

    2011-04-01

    As the increasing prevalence of resistant strains of respiratory bacterial pathogens has recently been reported, continuous monitoring of the susceptibility of clinical isolates to antibacterial agents is important. We performed a surveillance study focusing on the susceptibility of major respiratory bacterial pathogens in the northeastern region of Japan to carbapenems and control drugs. A total of 168 bacterial strains isolated from patients with respiratory tract infections in 2007 were collected and the minimum inhibitory concentration (MIC) determined. MIC data were subjected to pharmacokinetic/pharmacodynamic analysis with Monte Carlo simulation to calculate the probability of achieving the target of time above MIC with each carbapenem. All Moraxella catarrhalis, Streptococcus pneumoniae, and methicillin-sensitive Staphylococcus aureus isolates were susceptible to carbapenems. Despite the increasing prevalence of β-lactamase-nonproducing ampicillin-resistant strains, all Haemophilus influenzae isolates were susceptible to meropenem. For Pseudomonas aeruginosa, the susceptibility rates for meropenem and biapenem were 76.7%, and the highest probability of achieving pharmacodynamic target (40% of the time above MIC) was obtained with meropenem 0.5 g three times daily as a 4-h infusion (89.4%), followed by meropenem 0.5 g four times daily as a 1-h infusion (88.4%). Carbapenems have retained their position as key drugs for severe respiratory tract infections.

  13. Amoeba host-Legionella synchronization of amino acid auxotrophy and its role in bacterial adaptation and pathogenic evolution.

    Science.gov (United States)

    Price, Christopher T D; Richards, Ashley M; Von Dwingelo, Juanita E; Samara, Hala A; Abu Kwaik, Yousef

    2014-02-01

    Legionella pneumophila, the causative agent of Legionnaires' disease, invades and proliferates within a diverse range of free-living amoeba in the environment, but upon transmission to humans, the bacteria hijack alveolar macrophages. Intracellular proliferation of L. pneumophila in two evolutionarily distant hosts is facilitated by bacterial exploitation of conserved host processes that are targeted by bacterial protein effectors injected into the host cell. A key aspect of microbe-host interaction is microbial extraction of nutrients from the host, but understanding of this is still limited. AnkB functions as a nutritional virulence factor and promotes host proteasomal degradation of polyubiquitinated proteins generating gratuitous levels of limiting host cellular amino acids. Legionella pneumophila is auxotrophic for several amino acids including cysteine, which is a metabolically preferred source of carbon and energy during intracellular proliferation, but is limiting in both amoebae and humans. We propose that synchronization of bacterial amino acids auxotrophy with the host is a driving force in pathogenic evolution and nutritional adaptation of L. pneumophila and other intracellular bacteria to life within the host cell. Understanding microbial strategies of nutrient generation and acquisition in the host will provide novel antimicrobial strategies to disrupt pathogen access to essential sources of carbon and energy.

  14. A longitudinal study of lung bacterial pathogens in patients with primary ciliary dyskinesia

    DEFF Research Database (Denmark)

    C. Alanin, M.; G. Nielsen, K.; von Buchwald, C.

    2015-01-01

    In patients with primary ciliary dyskinesia (PCD), impaired mucociliary clearance leads to an accumulation of secretions in the airways and susceptibility to repeated bacterial infections. The primary aim of this study was to investigate the bacterial flora in non-chronic and chronic infections i...

  15. Functional analysis of alleged NOGGIN mutation G92E disproves its pathogenic relevance.

    Directory of Open Access Journals (Sweden)

    Julia Zimmer

    Full Text Available We identified an amino acid change (p.G92E in the Bone Morphogenetic Protein antagonist NOGGIN in a 22-month-old boy who presented with a unilateral brachydactyly type B phenotype. Brachydactyly type B is a skeletal malformation that has been associated with increased Bone Morphogenetic Protein pathway activation in other patients. Previously, the amino acid change p.G92E in NOGGIN was described as causing fibrodysplasia ossificans progressiva, a rare genetic disorder characterized by limb malformations and progressive heterotopic bone formation in soft tissues that, like Brachydactyly type B, is caused by increased activation of Bone Morphogenetic Protein signaling. To determine whether G92E-NOGGIN shows impaired antagonism that could lead to increased Bone Morphogenetic Protein signaling, we performed functional assays to evaluate inhibition of BMP signaling. Interestingly, wt-NOGGIN shows different inhibition efficacies towards various Bone Morphogenetic Proteins that are known to be essential in limb development. However, comparing the biological activity of G92E-NOGGIN with wt-NOGGIN, we observed that G92E-NOGGIN inhibits activation of bone morphogenetic protein signaling with equal efficiency as wt-NOGGIN, supporting that G92E-NOGGIN does not cause pathological effects. Genetic testing of the child's parents revealed the same amino acid change in the healthy father, further supporting that p.G92E is a neutral amino acid substitution in NOGGIN. We conclude that p.G92E represents a rare polymorphism of the NOGGIN gene-- causing neither brachydactyly nor fibrodysplasia ossificans progressiva. This study highlights that a given genetic variation should not be considered pathogenic unless supported by functional analyses.

  16. Practical benefits of knowing the enemy: Modern molecular tools for diagnosing the etiology of bacterial diseases and understanding the taxonomy and diversity of plant pathogenic bacteria

    Science.gov (United States)

    Knowing the identity of bacterial plant pathogens is essential to strategic and sustainable disease management. However, such identifications are linked to bacterial taxonomy, a complicated and changing discipline that depends on methods and information that often are not used by those who are diagn...

  17. Bacterial Pathogens in Ixodid Ticks from a Piedmont County in North Carolina: Prevalence of Rickettsial Organisms

    Science.gov (United States)

    2010-01-01

    scapularis-Pathogen prevalence-Rickettsia-Rickettsia amblyommii. Introduction TICK-BORNE ILLNESSES (TBis) are zoonoses involving pathogens...white- tailed deer, and emergence of Amblyomma americanum- associated zoonoses in the United States. CTMI 2007; 315: 289-324. Papin, JF, Vahrson, W

  18. Custom database development and biomarker discovery methods for MALDI-TOF mass spectrometry-based identification of high-consequence bacterial pathogens.

    Science.gov (United States)

    Tracz, Dobryan M; Tyler, Andrea D; Cunningham, Ian; Antonation, Kym S; Corbett, Cindi R

    2017-03-01

    A high-quality custom database of MALDI-TOF mass spectral profiles was developed with the goal of improving clinical diagnostic identification of high-consequence bacterial pathogens. A biomarker discovery method is presented for identifying and evaluating MALDI-TOF MS spectra to potentially differentiate biothreat bacteria from less-pathogenic near-neighbour species.

  19. Vitamin B12 uptake by intestinal microorganisms: mechanism and relevance to syndromes of intestinal bacterial overgrowth

    Science.gov (United States)

    Giannella, R. A.; Broitman, S. A.; Zamcheck, N.

    1971-01-01

    The mechanism of bacterial uptake of vitamin B12, the spectrum of microorganisms capable of such uptake, and the factors involved were the subject of this study. Bacterial uptake of vitamin B12 was found to be at least a two stage process. A primary uptake phase which was rapid (1 min or less), pH dependent, nontemperature dependent, did not require viable organisms and was insensitive to either the metabolic inhibitor dinitrophenol or to the sulfhydryl inhibitor N-ethyl-maleimide. Protein denaturation (formalin treatment or autoclaving) abolished all B12 uptake. This primary uptake phase is thought to represent adsorption to binding or “receptor” sites on the cell wall. Second stage uptake was slower, pH and temperature dependent, required living bacteria, and was abolished by either dinitrophenol or N-ethyl-maleimide. This phase is dependent upon metabolic processes and may reflect transfer of B12 from surface “receptor” sites into the bacterial cell. Although differences among organisms were observed in total 1 hr uptake, number of surface “receptor” sites, and relative avidities for B12, all organisms except Streptococcus fecalis shared the two stage mechanism. Two Gram-positive organisms. Bacillus subtilis and Group A streptococcus, demonstrated the highest 1 hr vitamin B12 uptake values; Gram-negative bacteria required 2,000-10,000 the number of organisms for comparable uptake. Binding constants (Km) varied from 5.05 ±1.67 × 10-10M for B. subtilis to 6.18 ±3.08 × 10-9M for Klebsiella pneumoniae which approximate the Km for human intrinsic factor (0.38 × 10-10M). Competition between bacteria and intrinsic factor for vitamin B12 may be inferred from the similarity of these constants. These observations suggest that a variety of enteric and nonenteric organisms, not requiring exogenous B12, may play a role in the pathogenesis of the vitamin B12 malabsorption found in the intestinal bacterial overgrowth syndromes. PMID:4994753

  20. Mass spectrometry-based bacterial proteomics: focus on dermatological associated microbial pathogens

    Directory of Open Access Journals (Sweden)

    Youcef eSoufi

    2016-02-01

    Full Text Available The composition of human skin acts as a natural habitat for various bacterial species that function in a commensal and symbiotic fashion. In a healthy individual, bacterial flora serves to protect the host. Under certain conditions such as minor trauma, impaired host immunity, or environmental factors, the risk of developing skin infections is increased. Although a large majority of bacterial associated skin infections are common, a portion can potentially manifest into clinically significant morbidity. For example, Gram positive species that typically reside on the skin such as Staphylococcus and Streptococcus can cause numerous epidermal (impetigo, ecthyma and dermal (cellulitis, necrotizing fasciitis, erysipelas skin infections. Moreover, the increasing incidence of bacterial antibiotic resistance represents a serious challenge to modern medicine and threatens the health care system. Therefore, it is critical to develop tools and strategies that can allow us to better elucidate the nature and mechanism of bacterial virulence. To this end, mass spectrometry (MS-based proteomics has been revolutionizing biomedical research, and has positively impacted the microbiology field. Advances in MS technologies have paved the way for numerous bacterial proteomes and their respective post translational modifications (PTMs to be accurately identified and quantified in a high throughput and robust fashion. This technological platform offers critical information with regards to signal transduction, adherence, and microbial-host interactions associated with bacterial pathogenesis. This mini-review serves to highlight the current progress proteomics has contributed towards the understanding of bacteria that are associated with skin related diseases, infections, and antibiotic resistance.

  1. Isolation and Characterization of Gut Bacterial Proteases Involved in Inducing Pathogenicity of Bacillus thuringiensis Toxin in Cotton Bollworm, Helicoverpa armigera

    Science.gov (United States)

    Regode, Visweshwar; Kuruba, Sreeramulu; Mohammad, Akbar S.; Sharma, Hari C.

    2016-01-01

    Bacillus thuringiensis toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac) to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation toward pro-Cry1Ac. Among 12 gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2, and IVS3) were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2, and IVS3 isolates were purified to 11.90-, 15.50-, and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40°C. Maximum inhibition of total proteolytic activity was exerted by phenylmethane sulfonyl fluoride followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65, and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity toward H. armigera. The gut bacterial isolates IVS1, IVS2, and IVS3 showed homology with B. thuringiensis (CP003763.1), Vibrio fischeri (CP000020.2), and Escherichia coli (CP011342.1), respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of B. thuringiensis protoxin and play a major role in inducing pathogenicity of B. thuringiensis toxins in H. armigera. PMID:27766093

  2. Isolation and characterization of gut bacterial proteases involved in inducing pathogenicity of Bacillus thuringiensis toxin in cotton bollworm, Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Visweshwar Regode

    2016-10-01

    Full Text Available Bacillus thuringiensis (Bt toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation towards pro-Cry1Ac. Among twelve gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2 and IVS3 were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2 and IVS3 isolates were purified to 11.90-, 15.50- and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40 oC. Maximum inhibition of total proteolytic activity was exerted by PMSF followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65 and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity towards H. armigera. The gut bacterial isolates IVS1, IVS2 and IVS3 showed homology with Bacillus thuringiensis (CP003763.1, Vibrio fischeri (CP000020.2 and Escherichia coli (CP011342.1, respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of Bt protoxin and play a major role in inducing pathogenicity of Bt toxins in H. armigera.

  3. Parallel evolution of a type IV secretion system in radiating lineages of the host-restricted bacterial pathogen Bartonella.

    Science.gov (United States)

    Engel, Philipp; Salzburger, Walter; Liesch, Marius; Chang, Chao-Chin; Maruyama, Soichi; Lanz, Christa; Calteau, Alexandra; Lajus, Aurélie; Médigue, Claudine; Schuster, Stephan C; Dehio, Christoph

    2011-02-10

    Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS), and thereby translocated Bartonella effector proteins (Beps), evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial pathogens

  4. Cytotoxic chromosomal targeting by CRISPR/Cas systems can reshape bacterial genomes and expel or remodel pathogenicity islands.

    Directory of Open Access Journals (Sweden)

    Reuben B Vercoe

    2013-04-01

    Full Text Available In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs and their associated (Cas proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2 involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas-mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA-targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity.

  5. Cytotoxic chromosomal targeting by CRISPR/Cas systems can reshape bacterial genomes and expel or remodel pathogenicity islands.

    Directory of Open Access Journals (Sweden)

    Reuben B Vercoe

    2013-04-01

    Full Text Available In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs and their associated (Cas proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2 involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas-mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA-targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity.

  6. Parallel evolution of a type IV secretion system in radiating lineages of the host-restricted bacterial pathogen Bartonella.

    Directory of Open Access Journals (Sweden)

    Philipp Engel

    2011-02-01

    Full Text Available Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS, and thereby translocated Bartonella effector proteins (Beps, evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial

  7. Cytotoxic Chromosomal Targeting by CRISPR/Cas Systems Can Reshape Bacterial Genomes and Expel or Remodel Pathogenicity Islands

    Science.gov (United States)

    Vercoe, Reuben B.; Chang, James T.; Dy, Ron L.; Taylor, Corinda; Gristwood, Tamzin; Clulow, James S.; Richter, Corinna; Przybilski, Rita; Pitman, Andrew R.; Fineran, Peter C.

    2013-01-01

    In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs) and their associated (Cas) proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2) involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas–mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM) beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA–targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity. PMID:23637624

  8. Photopolymerization of polydiacetylene in hybrid liposomes: effect of polymerization on stability and response to pathogenic bacterial toxins.

    Science.gov (United States)

    Thet, Naing Tun; Jamieson, William David; Laabei, Maisem; Mercer-Chalmers, June D; Jenkins, A Toby A

    2014-05-22

    Liposomes containing lipids and polydiacetylene (PDA) are hybrid systems encompassing both a fluid phospholipid membrane and a polymer scaffold (PDA). However, the biophysical role of PDA in such liposomes is not well understood. In this report, we studied the effects of photopolymerization of PDA on the stability of lipid-PDA liposomes, and their sensitivity to selected purified toxins and bacterial supernatants, using a fluorescence assay. Of the three different types of liposomes with variable lipid chain lengths that were chosen, the degree of polymerization had a significant impact on the long-term stability, and response, to external microbial exotoxins secreted by pathogenic bacteria, namely, Staphylococcus aureus and Pseudomonas aeruginosa. The degree of polymerization of TCDA played an important role in lipid-chain-length-dependent stabilization of lipid-PDA liposomes, as well as in their response to bacterial toxins of S. aureus and P. aeruginosa.

  9. Presence of potential bacterial pathogens in a municipal drinking water supply system.

    Science.gov (United States)

    Felföldi, T; Tarnóczai, Tímea; Homonnay, Z G

    2010-09-01

    The quality of drinking water is a major public concern, but the detection of most potential pathogens is not always included in drinking water hygienic monitoring or is only assessed with highly biased cultivation-based methods. In this study, the occurrence of Pseudomonas aeruginosa and Legionella spp. was examined with taxon-specific PCRs in samples taken at ten points of a municipal drinking water supply system in three months. Sequence analysis confirmed the positivity of samples and revealed a diverse community of legionellae. The results showed that chlorination was an important and effective disinfection method against pathogenic bacteria in drinking water, but pathogenic bacteria could reoccur in the system farther away from the chlorination point. No strong correlation was found between the presence of the investigated potentially pathogenic bacteria and the measured abiotic and biotic parameters within the investigated range. It is hypothesized that instead of physicochemical parameters, the main factors influencing the presence of pathogens in the drinking water were rather the composition of the microbial community, the biotic interactions between individual non-pathogenic and pathogenic microorganisms (competition or promotion of growth) and the structure of biofilm grown on the inner surface of the supply system.

  10. Nanoparticle targeting of Gram-positive and Gram-negative bacteria for magnetic-based separations of bacterial pathogens

    Science.gov (United States)

    Lu, Hoang D.; Yang, Shirley S.; Wilson, Brian K.; McManus, Simon A.; Chen, Christopher V. H.-H.; Prud'homme, Robert K.

    2017-02-01

    Antimicrobial resistance is a healthcare problem of increasing significance, and there is increasing interest in developing new tools to address bacterial infections. Bacteria-targeting nanoparticles hold promise to improve drug efficacy, compliance, and safety. In addition, nanoparticles can also be used for novel applications, such as bacterial imaging or bioseperations. We here present the use of a scalable block-copolymer-directed self-assembly process, Flash NanoPrecipitation, to form zinc(II)-bis(dipicolylamine) modified nanoparticles that bind to both Gram-positive and Gram-negative bacteria with specificity. Particles have tunable surface ligand densities that change particle avidity and binding efficacy. A variety of materials can be encapsulated into the core of the particles, such as optical dyes or iron oxide colloids, to produce imageable and magnetically active bacterial targeting constructs. As a proof-of-concept, these particles are used to bind and separate bacteria from solution in a magnetic column. Magnetic manipulation and separation would translate to a platform for pathogen identification or removal. These magnetic and targeted nanoparticles enable new methods to address bacterial infections.

  11. Nanoparticle targeting of Gram-positive and Gram-negative bacteria for magnetic-based separations of bacterial pathogens

    Science.gov (United States)

    Lu, Hoang D.; Yang, Shirley S.; Wilson, Brian K.; McManus, Simon A.; Chen, Christopher V. H.-H.; Prud'homme, Robert K.

    2017-04-01

    Antimicrobial resistance is a healthcare problem of increasing significance, and there is increasing interest in developing new tools to address bacterial infections. Bacteria-targeting nanoparticles hold promise to improve drug efficacy, compliance, and safety. In addition, nanoparticles can also be used for novel applications, such as bacterial imaging or bioseperations. We here present the use of a scalable block-copolymer-directed self-assembly process, Flash NanoPrecipitation, to form zinc(II)-bis(dipicolylamine) modified nanoparticles that bind to both Gram-positive and Gram-negative bacteria with specificity. Particles have tunable surface ligand densities that change particle avidity and binding efficacy. A variety of materials can be encapsulated into the core of the particles, such as optical dyes or iron oxide colloids, to produce imageable and magnetically active bacterial targeting constructs. As a proof-of-concept, these particles are used to bind and separate bacteria from solution in a magnetic column. Magnetic manipulation and separation would translate to a platform for pathogen identification or removal. These magnetic and targeted nanoparticles enable new methods to address bacterial infections.

  12. Molecular basis for manganese sequestration by calprotectin and roles in the innate immune response to invading bacterial pathogens.

    Science.gov (United States)

    Damo, Steven M; Kehl-Fie, Thomas E; Sugitani, Norie; Holt, Marilyn E; Rathi, Subodh; Murphy, Wesley J; Zhang, Yaofang; Betz, Christine; Hench, Laura; Fritz, Günter; Skaar, Eric P; Chazin, Walter J

    2013-03-05

    The S100A8/S100A9 heterodimer calprotectin (CP) functions in the host response to pathogens through a mechanism termed "nutritional immunity." CP binds Mn(2+) and Zn(2+) with high affinity and starves bacteria of these essential nutrients. Combining biophysical, structural, and microbiological analysis, we identified the molecular basis of Mn(2+) sequestration. The asymmetry of the CP heterodimer creates a single Mn(2+)-binding site from six histidine residues, which distinguishes CP from all other Mn(2+)-binding proteins. Analysis of CP mutants with altered metal-binding properties revealed that, despite both Mn(2+) and Zn(2+) being essential metals, maximal growth inhibition of multiple bacterial pathogens requires Mn(2+) sequestration. These data establish the importance of Mn(2+) sequestration in defense against infection, explain the broad-spectrum antimicrobial activity of CP relative to other S100 proteins, and clarify the impact of metal depletion on the innate immune response to infection.

  13. Pseudomonas fluorescens filamentous hemagglutinin, an iron-regulated protein, is an important virulence factor that modulates bacterial pathogenicity

    Directory of Open Access Journals (Sweden)

    Yuan-yuan Sun

    2016-08-01

    Full Text Available Pseudomonas fluorescens is a common bacterial pathogen to a wide range of aquaculture animals including various species of fish. In this study, we employed proteomic analysis and identified filamentous hemagglutinin (FHA as an iron-responsive protein secreted by TSS, a pathogenic P. fluorescens isolate. In vitro study showed that compared to the wild type, the fha mutant TSSfha (i exhibited a largely similar vegetative growth profile but significantly retarded in the ability of biofilm growth and producing extracellular matrix, (ii displayed no apparent flagella and motility, (iii was defective in the attachment to host cells and unable to form self-aggregation, (iv displayed markedly reduced capacity of hemagglutination and surviving in host serum. In vivo infection analysis revealed that TSSfha was significantly attenuated in the ability of dissemination in fish tissues and inducing host mortality, and that antibody blocking of the natural FHA produced by the wild type TSS impaired the infectivity of the pathogen. Furthermore, when introduced into turbot as a subunit vaccine, recombinant FHA elicited a significant protection against lethal TSS challenge. Taken together, these results indicate for the first time that P. fluorescens FHA is a key virulence factor essential to multiple biological processes associated with pathogenicity.

  14. Bottlenecks in the Transferability of Antibiotic Resistance from Natural Ecosystems to Human Bacterial Pathogens

    OpenAIRE

    Martínez, José L.

    2012-01-01

    It is generally accepted that resistance genes acquired by human pathogens through horizontal gene transfer originated in environmental, non-pathogenic bacteria. As a consequence, there is increasing concern on the roles that natural, non-clinical ecosystems, may play in the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance on their expression in a heterologous host is much larger than what is actually found in human...

  15. Evaluation of bacterial pathogens in paediatric poliovirus-positive faecal specimens

    Institute of Scientific and Technical Information of China (English)

    Adenike AOOgunshe; Oluwafunmilayo GOyero; Olalekan POlabode

    2009-01-01

    Objective:To evaluate the in vitro inhibitory potential of commonly available antibiotic (discs)and paediatric suspensions against bacterial species from polio-positive faecal specimens.Methods:Commonly available anti-biotic (discs)and oral,paediatric suspensions were screened for in vitro inhibitory activities against bacterial species from infantile polio-positive faecal specimens,using agar disc-diffusion and modified agar well-diffu-sion methods.Results:Isolated bacteria were Bacillus cereus,B.subtilis,Staphylococcus aureus,Streptococcus pneumoniae,Aeromonas hydrophila,Citrobacter aerogenes,Escherichia coli,Enterobacter aerogenes,Klebsiella pneumoniae,Pseudomonas aeruginosa,Proteus mirabilis,Pr.vulgaris,Shigella dysenteriae,Sh.flexneri,Sh. sonnei and Vibrio parahaemolyticus.Overall phenotypic antibiotic susceptibility rates among Gram-positive bac-terial species were between 33.3% (augmentin)and 75.0% (chloramphenicol,erythromycin and gentami-cin);higher susceptibility rates (48.6%-100.0%)were recorded among Gram-negative bacterial species, while between 7.8% /10.1% (metronidazole /ampicillin)and 25.2% /28.1 % (cotrimoxazole /septrin) were recorded towards paediatric antibiotics.Conclusions:Bacterial species from polio-positive fecal speci-mens are minimally susceptible to commonly available oral paediatric antibiotic suspensions in Nigeria.

  16. Autonomous Marine Robotic Technology Reveals an Expansive Benthic Bacterial Community Relevant to Regional Nitrogen Biogeochemistry.

    Science.gov (United States)

    Valentine, David L; Fisher, G Burch; Pizarro, Oscar; Kaiser, Carl L; Yoerger, Dana; Breier, John A; Tarn, Jonathan

    2016-10-06

    Benthic accumulations of filamentous, mat-forming bacteria occur throughout the oceans where bisulfide mingles with oxygen or nitrate, providing key but poorly quantified linkages between elemental cycles of carbon, nitrogen and sulfur. Here we used the autonomous underwater vehicle Sentry to conduct a contiguous, 12.5 km photoimaging survey of sea-floor colonies of filamentous bacteria between 80 and 579 m water depth, spanning the continental shelf to the deep suboxic waters of the Santa Barbara Basin (SBB). The survey provided >31 000 images and revealed contiguous, white-colored bacterial colonization coating > ∼80% of the ocean floor and spanning over 1.6 km, between 487 and 523 m water depth. Based on their localization within the stratified waters of the SBB we hypothesize a dynamic and annular biogeochemical zonation by which the bacteria capitalize on periodic flushing events to accumulate and utilize nitrate. Oceanographic time series data bracket the imaging survey and indicate rapid and contemporaneous nitrate loss, while autonomous capture of microbial communities from the benthic boundary layer concurrent with imaging provides possible identities for the responsible bacteria. Based on these observations we explore the ecological context of such mats and their possible importance in the nitrogen cycle of the SBB.

  17. Pattern of Bacterial Pathogens and Their Susceptibility Isolated from Surgical Site Infections at Selected Referral Hospitals, Addis Ababa, Ethiopia

    Directory of Open Access Journals (Sweden)

    Walelign Dessie

    2016-01-01

    Full Text Available Background. The emergence of multidrug resistant bacterial pathogens in hospitals is becoming a challenge for surgeons to treat hospital acquired infections. Objective. To determine bacterial pathogens and drug susceptibility isolated from surgical site infections at St. Paul Specialized Hospital Millennium Medical College and Yekatit 12 Referral Hospital Medical College, Addis Ababa, Ethiopia. Methods. A cross-sectional study was conducted between October 2013 and March 2014 on 107 surgical site infected patients. Wound specimens were collected using sterile cotton swab and processed as per standard operative procedures in appropriate culture media; and susceptibility testing was done using Kirby-Bauer disc diffusion technique. The data were analyzed by using SPSS version 20. Result. From a total of 107 swabs collected, 90 (84.1% were culture positive and 104 organisms were isolated. E. coli (24 (23.1% was the most common organism isolated followed by multidrug resistant Acinetobacter species (23 (22.1%. More than 58 (75% of the Gram negative isolates showed multiple antibiotic resistance (resistance ≥ 5 drugs. Pan-antibiotic resistance was noted among 8 (34.8% Acinetobacter species and 3 (12.5% E. coli. This calls for abstinence from antibiotic abuse. Conclusion. Gram negative bacteria were the most important isolates accounting for 76 (73.1%. Ampicillin, amoxicillin, penicillin, cephazoline, and tetracycline showed resistance while gentamicin and ciprofloxacin were relatively effective antimicrobials.

  18. Foliar application of the leaf-colonizing yeast Pseudozyma churashimaensis elicits systemic defense of pepper against bacterial and viral pathogens

    Science.gov (United States)

    Lee, Gahyung; Lee, Sang-Heon; Kim, Kyung Mo; Ryu, Choong-Min

    2017-01-01

    Yeast associates with many plant parts including the phyllosphere, where it is subject to harsh environmental conditions. Few studies have reported on biological control of foliar pathogens by yeast. Here, we newly isolated leaf-colonizing yeasts from leaves of field-grown pepper plants in a major pepper production area of South Korea. The yeast was isolated using semi-selective medium supplemented with rifampicin to inhibit bacterial growth and its disease control capacity against Xanthomonas axonopodis infection of pepper plants in the greenhouse was evaluated. Of 838 isolated yeasts, foliar spray of Pseudozyma churashimaensis strain RGJ1 at 108 cfu/mL conferred significant protection against X. axonopodis and unexpectedly against Cucumber mosaic virus, Pepper mottle virus, Pepper mild mottle virus, and Broad bean wilt virus under field conditions. Direct antagonism between strain RGJ1 and X. axonopodis was not detected from co-culture assays, suggesting that disease is suppressed via induced resistance. Additional molecular analysis of the induced resistance marker genes Capsicum annuum Pathogenesis-Related (CaPR) 4 and CaPR5 indicated that strain RGJ1 elicited plant defense priming. To our knowledge, this study is the first report of plant protection against bacterial and viral pathogens mediated by a leaf-colonizing yeast and has potential for effective disease management in the field. PMID:28071648

  19. The adaptive response of bacterial food-borne pathogens in the environment, host and food: Implications for food safety.

    Science.gov (United States)

    Alvarez-Ordóñez, Avelino; Broussolle, Véronique; Colin, Pierre; Nguyen-The, Christophe; Prieto, Miguel

    2015-11-20

    Bacteria are constantly faced to stress situations in their ecological niches, the food and the host gastrointestinal tract. The capacity to detect and respond to surrounding changes is crucial for bacterial pathogens to survive or grow in changing environments. To this purpose, cells have evolved various sophisticated networks designed to protect against stressors or repair damage caused by them. Challenges can occur during production of foods when subjected to processing, and after food ingestion when confronted with host defensive barriers. Some pathogenic bacteria have shown the capacity to develop stable resistance against extreme conditions within a defined genomic context and a limited number of generations. On the other hand, bacteria can also respond to adverse conditions in a transient manner, through the so-called stress tolerance responses. Bacterial stress tolerance responses include both structural and physiological modifications in the cell and are mediated by complex genetic regulatory machinery. Major aspects in the adaptive response are the sensing mechanisms, the characterization of cell defensive systems, such as the operation of regulatory proteins (e.g. RpoS), the induction of homeostatic and repair systems, the synthesis of shock response proteins, and the modifications of cell membranes, particularly in their fatty acid composition and physical properties. This article reviews certain strategies used by food-borne bacteria to respond to particular stresses (acid, cold stress, extreme pressure) in a permanent or transient manner and discusses the implications that such adaptive responses pose for food safety.

  20. The anti-biofilm potential of pomegranate (Punica granatum L.) extract against human bacterial and fungal pathogens.

    Science.gov (United States)

    Bakkiyaraj, Dhamodharan; Nandhini, Janarthanam Rathna; Malathy, Balakumar; Pandian, Shunmugiah Karutha

    2013-09-01

    Infectious diseases caused by bacteria and fungi are the major cause of morbidity and mortality across the globe. Multi-drug resistance in these pathogens augments the complexity and severity of the diseases. Various studies have shown the role of biofilms in multi-drug resistance, where the pathogen resides inside a protective coat made of extracellular polymeric substances. Since biofilms directly influence the virulence and pathogenicity of a pathogen, it is optimal to employ a strategy that effectively inhibits the formation of biofilm. Pomegranate is a common food and is also used traditionally to treat various ailments. This study assessed the anti-biofilm activity of a methanolic extract of pomegranate against bacterial and fungal pathogens. Methanolic extract of pomegranate was shown to inhibit the formation of biofilms by Staphylococcus aureus, methicillin resistant S. aureus, Escherichia coli, and Candida albicans. Apart from inhibiting the formation of biofilm, pomegranate extract disrupted pre-formed biofilms and inhibited germ tube formation, a virulence trait, in C. albicans. Characterization of the methanolic extract of pomegranate revealed the presence of ellagic acid (2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione) as the major component. Ellagic acid is a bioactive tannin known for its antioxidant, anticancer, and anti-inflammatory properties. Further studies revealed the ability of ellagic acid to inhibit the growth of all species in suspension at higher concentrations (>75 μg ml(-1)) and biofilm formation at lower concentrations (pomegranate for the treatment of human ailments.

  1. A potent fish pathogenic bacterial killer Streptomyces sp. isolated from the soils of east coast region, South India

    Directory of Open Access Journals (Sweden)

    Durairaj Thirumurugan

    2013-10-01

    Full Text Available Objective: To investigate the potentiality of the marine actinobacteria isolated from marine soil against fish pathogenic bacteria. Methods: In the present study, a total of 33 soil samples were collected from the Bay of Bengal, east coast region (ECR of Tamilnadu, South India. Then they were used for the isolation of actinobacteria by using conventional serial dilution technique on starch casein agar medium. The antibacterial activities of the actinobacteria were screened primarily by using cross streak plate method against fish pathogenic bacteria namely Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio cholera, Aeromonas sp. and Pseudomonas sp. The antimicrobial efficacy of the selected isolates was carried out with various organic solvents, and finally the active compound was subjected to chromatographic techniques including TLC and GC-MS. Results: Of the 82 actinobacteria isolated, 21 (26% isolates were possessed antibacterial activity against fish pathogenic bacteria. Out of 21 antibacterial isolates, the isolate ECR77 was selected for further study based on its potential activity against fish pathogenic bacteria. Of the various solvents tested, the ethyl acetate extract had good antibacterial activity against the tested bacterial pathogens. The isolate ECR77 grew well on oat meal agar medium with 2% salt level at 35 °C. GC-MS study found that the presence of bioactive compounds namely tetradecanoic acid, n-hexadecanoic acid and octadecanoic acid. The morphological, physiological, biochemical and cultural characteristics of the potential isolate were supported the identity up to generic level as Streptomyces sp. ECR77. Conclusions: The results obtained from this study concludes that the ECR soils of South India is a hot spot of novel bioactive compound producing marine actinobacteria with great pharmaceutical values.

  2. A potent fish pathogenic bacterial killer Streptomyces sp. isolated from the soils of east coast region, South India

    Institute of Scientific and Technical Information of China (English)

    Durairaj Thirumurugan; Ramasamy Vijayakumar

    2013-01-01

    Objective: To investigate the potentiality of the marine actinobacteria isolated from marine soil against fish pathogenic bacteria.Methods:east coast region (ECR) of Tamilnadu, South India. Then they were used for the isolation of actinobacteria by using conventional serial dilution technique on starch casein agar medium. The antibacterial activities of the actinobacteria were screened primarily by using cross streak plate method against fish pathogenic bacteria namely Vibrio alginolyticus, Vibrio parahaemolyticus,Vibrio cholera, Aeromonas sp. and Pseudomonas sp. The antimicrobial efficacy of the selected isolates was carried out with various organic solvents, and finally the active compound was subjected to chromatographic techniques including TLC and GC-MS.Results:In the present study, a total of 33 soil samples were collected from the Bay of Bengal, against fish pathogenic bacteria. Out of 21 antibacterial isolates, the isolate ECR77 was selected for further study based on its potential activity against fish pathogenic bacteria. Of the various solvents tested, the ethyl acetate extract had good antibacterial activity against the tested bacterial pathogens. The isolate ECR77 grew well on oat meal agar medium with 2% salt level at 35 °C. GC-MS study found that the presence of bioactive compounds namely tetradecanoic acid,n-hexadecanoic acid and octadecanoic acid. The morphological, physiological, biochemical and cultural characteristics of the potential isolate were supported the identity up to generic level asStreptomyces sp. ECR77. Conclusions: The results obtained from this study concludes that the ECR soils of South India is a hot spot of novel bioactive compound producing marine actinobacteria with great pharmaceutical values. Of the 82 actinobacteria isolated, 21 (26%) isolates were possessed antibacterial activity.

  3. Triclosan Resistance in a Bacterial Fish Pathogen, Aeromonas salmonicida subsp. salmonicida, is Mediated by an Enoyl Reductase, FabV.

    Science.gov (United States)

    Khan, Raees; Lee, Myung Hwan; Joo, Hae-Jin; Jung, Yong-Hoon; Ahmad, Shabir; Choi, Jin-Hee; Lee, Seon-Woo

    2015-04-01

    Triclosan, the widely used biocide, specifically targets enoyl-acyl carrier protein reductase (ENR) in the bacterial fatty acid synthesis system. Although the fish pathogen Aeromonas salmonicida subsp. salmonicida exhibits triclosan resistance, the nature of this resistance has not been elucidated. Here, we aimed to characterize the triclosan resistance of A. salmonicida subsp. salmonicida causing furunculosis. The fosmid library of triclosan-resistant A. salmonicida subsp. salmonicida was constructed to select a fosmid clone showing triclosan resistance. With the fosmid clone showing triclosan resistance, a subsequent secondary library search resulted in the selection of subclone pTSR-1. DNA sequence analysis of pTSR-1 revealed the presence of a chromosomal-borne fabV-encoding ENR homolog. The ENR of A. salmonicida (FabVas) exhibited significant homology with previously known FabV, including the catalytic domain YX(8)K. fabVas introduction into E. coli dramatically increased its resistance to triclosan. Heterologous expression of FabVas might functionally replace the triclosan-sensitive FabI in vivo to confer E. coli with triclosan resistance. A genome-wide search for fabVas homologs revealed the presence of an additional fabV gene (fabVas2) paralog in A. salmonicida strains and the fabVas orthologs from other gram-negative fish pathogens. Both of the potential FabV ENRs expressed similarly with or without triclosan supplement. This is the first report about the presence of two potential FabV ENRs in a single pathogenic bacterium. Our result suggests that triclosan-resistant ENRs are widely distributed in various bacteria in nature, and the wide use of this biocide can spread these triclosan-tolerant ENRs among fish pathogens and other pathogenic bacteria.

  4. Bacterial inclusion bodies as potential synthetic devices for pathogen recognition and a therapeutic substance release.

    Science.gov (United States)

    Talafová, Klaudia; Hrabárová, Eva; Chorvát, Dušan; Nahálka, Jozef

    2013-02-07

    Adhesins of pathogens recognise the glycans on the host cell and mediate adherence. They are also crucial for determining the tissue preferences of pathogens. Currently, glyco-nanomaterials provide potential tool for antimicrobial therapy. We demonstrate that properly glyco-tailored inclusion bodies can specifically bind pathogen adhesins and release therapeutic substances. In this paper, we describe the preparation of tailored inclusion bodies via the conjugation of indicator protein aggregated to form inclusion bodies with soluble proteins. Whereas the indicator protein represents a remedy, the soluble proteins play a role in pathogen recognition. For conjugation, glutaraldehyde was used as linker. The treatment of conjugates with polar lysine, which was used to inactivate the residual glutaraldehyde, inhibited unwanted hydrophobic interactions between inclusion bodies. The tailored inclusion bodies specifically interacted with the SabA adhesin from Helicobacter pylori aggregated to form inclusion bodies that were bound to the sialic acids decorating the surface of human erythrocytes. We also tested the release of indicator proteins from the inclusion bodies using sortase A and Ssp DNAB intein self-cleaving modules, respectively. Sortase A released proteins in a relatively short period of time, whereas the intein cleavage took several weeks. The tailored inclusion bodies are promising "nanopills" for biomedical applications. They are able to specifically target the pathogen, while a self-cleaving module releases a soluble remedy. Various self-cleaving modules can be enabled to achieve the diverse pace of remedy release.

  5. Assessment of the Antimicrobial Activity of Olive Leaf Extract Against Foodborne Bacterial Pathogens

    Science.gov (United States)

    Liu, Yanhong; McKeever, Lindsay C.; Malik, Nasir S. A.

    2017-01-01

    Olive leaf extract (OLE) has been used traditionally as a herbal supplement since it contains polyphenolic compounds with beneficial properties ranging from increasing energy levels, lowering blood pressure, and supporting the cardiovascular and immune systems. In addition to the beneficial effects on human health, OLE also has antimicrobial properties. The aim of this work was to investigate the antimicrobial effect of OLE against major foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis. Our results demonstrated that at a concentration of 62.5 mg/ml, OLE almost completely inhibited the growth of these three pathogens. In addition, OLE also reduced cell motility in L. monocytogenes, which correlated with the absence of flagella as shown by scanning electron microscopy. Moreover, OLE inhibited biofilm formation in L. monocytogenes and S. Enteritidis. Taken together, OLE, as a natural product, has the potential to be used as an antimicrobial to control foodborne pathogens. PMID:28210244

  6. Characterization and Identification of Two Opportunistic Human Bacterial Pathogens in Rice

    Institute of Scientific and Technical Information of China (English)

    LUO Yuan-chan; XIE Guan-lin; ZHANG Li-xin; AN Gilmyong; FANG Yuan; LUO Jin-yan; HAO Xiao-juan; ZHAO Si-feng

    2006-01-01

    Burkholderia cepacia (Bc) and Pseudomonas aeruginosa (Pa) are both biocontrol agents in agriculture and opportunistic human pathogens in hospitals. Effective management and utilization practice is needed to understand their characteristics and distribution in rice. During the last decade, the two opportunistic human pathogens were detected in 631 samples of rice seed and 117 samples of rice plant in plain, highland and mountainous rice growing areas of China. Bc and Pa were primarily differentiated by common bacteriological characteristics and pathogenic tests and then identified into species by Biolog and FAME tests. However,the genotypes of Bc still could not be distinguished. It has been noted that the Bc and Pa mainly existed in rice root with the highest distribution frequency in plain areas ( 6.1% and 16.1%) and lowest in the mountainous areas (1.0% and 7.8%).

  7. Bacterial-based systems for expression and purification of recombinant Lassa virus proteins of immunological relevance

    Directory of Open Access Journals (Sweden)

    Cashman Kathleen A

    2008-06-01

    Full Text Available Abstract Background There is a significant requirement for the development and acquisition of reagents that will facilitate effective diagnosis, treatment, and prevention of Lassa fever. In this regard, recombinant Lassa virus (LASV proteins may serve as valuable tools in diverse antiviral applications. Bacterial-based systems were engineered for expression and purification of recombinant LASV nucleoprotein (NP, glycoprotein 1 (GP1, and glycoprotein 2 (GP2. Results Full-length NP and the ectodomains of GP1 and GP2 were generated as maltose-binding protein (MBP fusions in the Rosetta strains of Escherichia coli (E. coli using pMAL-c2x vectors. Average fusion protein yields per liter of culture for MBP-NP, MBP-GP1, and MBP-GP2 were 10 mg, 9 mg, and 9 mg, respectively. Each protein was captured from cell lysates using amylose resin, cleaved with Factor Xa, and purified using size-exclusion chromatography (SEC. Fermentation cultures resulted in average yields per liter of 1.6 mg, 1.5 mg, and 0.7 mg of purified NP, GP1 and GP2, respectively. LASV-specific antibodies in human convalescent sera specifically detected each of the purified recombinant LASV proteins, highlighting their utility in diagnostic applications. In addition, mouse hyperimmune ascitic fluids (MHAF against a panel of Old and New World arenaviruses demonstrated selective cross reactivity with LASV proteins in Western blot and enzyme-linked immunosorbent assay (ELISA. Conclusion These results demonstrate the potential for developing broadly reactive immunological assays that employ all three arenaviral proteins individually and in combination.

  8. Foodborne Bacterial Pathogens in Retail Prepacked Ready-to-Eat Mixed Ingredient Salads.

    Science.gov (United States)

    Söderqvist, Karin; Thisted Lambertz, Susanne; Vågsholm, Ivar; Boqvist, Sofia

    2016-06-01

    Prepacked ready-to-eat mixed ingredient salads (RTE salads) are readily available whole meals that include a variety of ingredients such as raw vegetables, cooked meat, and pasta. As part of a trend toward healthy convenience foods, RTE salads have become an increasingly popular product among consumers. However, data on the incidence of foodborne pathogens in RTE salads are scarce. In this study, the microbiological safety of 141 RTE salads containing chicken, ham, or smoked salmon was investigated. Salad samples were collected at retail and analyzed using standard methods for Listeria monocytogenes, Shiga toxin-producing Escherichia coli (STEC), pathogenic Yersinia enterocolitica, Salmonella, and Campylobacter spp.L. monocytogenes was isolated from two (1.4%) of the RTE salad samples. Seven (5.0%) of the samples were positive for the ail gene (present in all human pathogenic Y. enterocolitica isolates) and three (2.1%) of the samples were positive for the Shiga toxin genes stx1 and/or stx2. However, no strains of pathogenic Y.enterocolitica or STEC were isolated. Thus, pathogens were found or suspected in almost 1 of 10 RTE salads investigated, and pathogenic bacteria probably are present in various RTE salads from retail premises in Sweden. Because RTE salads are intended to be consumed without heat treatment, control of the ingredients and production hygiene is essential to maintain consumer safety. The recommended maximum storage temperature for RTE salads varies among countries but can be up to 8°C (e.g., in Sweden). Even during a short shelf life (3 to 5 days), storage at 8°C can enable growth of psychrotrophs such as L. monocytogenes and Y. enterocolitica. The maximum storage temperature should therefore be reduced.

  9. Specific detection of common pathogens of acute bacterial meningitis using an internally controlled tetraplex-PCR assay.

    Science.gov (United States)

    Farahani, Hamidreza; Ghaznavi-Rad, Ehsanollah; Mondanizadeh, Mahdieh; MirabSamiee, Siamak; Khansarinejad, Behzad

    2016-08-01

    Accurate and timely diagnosis of acute bacterial meningitis is critical for antimicrobial treatment of patients. Although PCR-based methods have been widely used for the diagnosis of acute meningitis caused by bacterial pathogens, the main disadvantage of these methods is their high cost. This disadvantage has hampered the widespread use of molecular assays in many developing countries. The application of multiplex assays and "in-house" protocols are two main approaches that can reduce the overall cost of a molecular test. In the present study, an internally controlled tetraplex-PCR was developed and validated for the specific detection of Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae in cerebrospinal fluid (CSF) samples. The analysis of a panel of other human pathogens showed no cross-reactivity in the assay. The analytical sensitivity of the in-house assay was 792.3 copies/ml, when all three bacteria were presentin the specimens. This value was calculated as 444.5, 283.7, 127.8 copies/ml when only S. pneumoniae, N. meningitidis and H. influenzae, respectively, were present. To demonstrate the diagnostic performance of the assay, a total of 150 archival CSF samples were tested and compared with a commercial multiplex real-time PCR kit. A diagnostic sensitivity of 92.8% and a specificity of 95.1% were determined for the present tetraplex-PCR assay. The results indicate that the established method is sensitive, specific and cost-effective, and can be used particularly in situations where the high cost of commercial kits prevents the use of molecular methods for the diagnosis of bacterial meningitis.

  10. Detection of Pathogenic Biofilms with Bacterial Amyloid Targeting Fluorescent Probe, CDy11

    DEFF Research Database (Denmark)

    Jun-Young, Kim; Srikanta, Sahu; Yin-Hoe, Yau

    2016-01-01

    Bacterial biofilms are responsible for a wide range of persistent infections. In the clinic, diagnosis of biofilm-associated infections relies heavily on culturing methods, which fail to detect nonculturable bacteria. Identification of novel fluorescent probes for biofilm imaging will greatly fac...

  11. Multidrug Efflux Pumps from Enterobacteriaceae, Vibrio cholerae and Staphylococcus aureus Bacterial Food Pathogens

    Directory of Open Access Journals (Sweden)

    Jody L. Andersen

    2015-01-01

    Full Text Available Foodborne illnesses caused by bacterial microorganisms are common worldwide and constitute a serious public health concern. In particular, microorganisms belonging to the Enterobacteriaceae and Vibrionaceae families of Gram-negative bacteria, and to the Staphylococcus genus of Gram-positive bacteria are important causative agents of food poisoning and infection in the gastrointestinal tract of humans. Recently, variants of these bacteria have developed resistance to medically important chemotherapeutic agents. Multidrug resistant Escherichia coli, Salmonella enterica, Vibrio cholerae, Enterobacter spp., and Staphylococcus aureus are becoming increasingly recalcitrant to clinical treatment in human patients. Of the various bacterial resistance mechanisms against antimicrobial agents, multidrug efflux pumps comprise a major cause of multiple drug resistance. These multidrug efflux pump systems reside in the biological membrane of the bacteria and actively extrude antimicrobial agents from bacterial cells. This review article summarizes the evolution of these bacterial drug efflux pump systems from a molecular biological standpoint and provides a framework for future work aimed at reducing the conditions that foster dissemination of these multidrug resistant causative agents through human populations.

  12. Capsaicin-sensitive vagal afferent neurons contribute to the detection of pathogenic bacterial colonization in the gut.

    Science.gov (United States)

    Riley, T P; Neal-McKinney, J M; Buelow, D R; Konkel, M E; Simasko, S M

    2013-04-15

    Vagal activation can reduce inflammation and disease activity in various animal models of intestinal inflammation via the cholinergic anti-inflammatory pathway. In the current model of this pathway, activation of descending vagal efferents is dependent on a signal initiated by stimulation of vagal afferents. However, little is known about how vagal afferents are activated, especially in the context of subclinical or clinical pathogenic bacterial infection. To address this question, we first determined if selective lesions of capsaicin-sensitive vagal afferents altered c-Fos expression in the nucleus of the solitary tract (nTS) after mice were inoculated with either Campylobacter jejuni or Salmonella typhimurium. Our results demonstrate that the activation of nTS neurons by intraluminal pathogenic bacteria is dependent on intact, capsaicin sensitive vagal afferents. We next determined if inflammatory mediators could cause the observed increase in c-Fos expression in the nTS by a direct action on vagal afferents. This was tested by the use of single-cell calcium measurements in cultured vagal afferent neurons. We found that tumor necrosis factor alpha (TNFα) and lipopolysaccharide (LPS) directly activate cultured vagal afferent neurons and that almost all TNFα and LPS responsive neurons were sensitive to capsaicin. We conclude that activation of the afferent arm of the parasympathetic neuroimmune reflex by pathogenic bacteria in the gut is dependent on capsaicin sensitive vagal afferent neurons and that the release of inflammatory mediators into intestinal tissue can be directly sensed by these neurons.

  13. Effects of climate change on the persistence and dispersal of foodborne bacterial pathogens in the outdoor environment: A review.

    Science.gov (United States)

    Hellberg, Rosalee S; Chu, Eric

    2016-08-01

    According to the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal. Over the coming century, warming trends such as increased duration and frequency of heat waves and hot extremes are expected in some areas, as well as increased intensity of some storm systems. Climate-induced trends will impact the persistence and dispersal of foodborne pathogens in myriad ways, especially for environmentally ubiquitous and/or zoonotic microorganisms. Animal hosts of foodborne pathogens are also expected to be impacted by climate change through the introduction of increased physiological stress and, in some cases, altered geographic ranges and seasonality. This review article examines the effects of climatic factors, such as temperature, rainfall, drought and wind, on the environmental dispersal and persistence of bacterial foodborne pathogens, namely, Bacillus cereus, Brucella, Campylobacter, Clostridium, Escherichia coli, Listeria monocytogenes, Salmonella, Staphylococcus aureus, Vibrio and Yersinia enterocolitica. These relationships are then used to predict how future climatic changes will impact the activity of these microorganisms in the outdoor environment and associated food safety issues. The development of predictive models that quantify these complex relationships will also be discussed, as well as the potential impacts of climate change on transmission of foodborne disease from animal hosts.

  14. [Involvement of soluble mediators of inflammation in the pathogenic agent interaction--immune system in acute bacterial meningitis].

    Science.gov (United States)

    Lerescu, L; Tucureanu, C; Caraş, Iuliana; Pitica, Ramona; Ungureanu, Vasilica; Sălăgeanu, Aurora

    2008-01-01

    Acute Bacterial Meningitis is a medical emergency, which warrants early diagnosis and aggressive therapy, which in most cases must be initiated as an "empirical" treatment. Such an approach needs permanent epidemiological surveillance due to the major variability of the etiological agents depending upon time, geographical areas and demographic characteristics of the population. A program for the surveillance of meningitis is in progress in Romania, but the available clinical inbformation is incomplete and not well documented by paraclinical data, poorly reflecting the real incidence of the disease. The specific anatomic localization of the disease has major influences on the antiinfectious immune response. Inflammation is involved in the disease pathogenesis, especially in promotion and evolution of neurological sequelae (neuronal demyelinisation and degeneration) even in case of pathogen clearance following antimicrobial therapy. Activation of the immune response in a immunologically "privileged "region can lead to the break of tolerance and induction of autoimmunity (neuronal degenerescence). On the other hand, an efficient immune response is necessary for the clearance of pathogenic agents. A detailed investigation of the interaction between pathogenic agents and the immune system in relation to the particular meningeal localization and also a study on the involvement of soluble mediators of inflammation (cytokines, chemokines) in the pathogenesis of meningitis might prove useful for differential diagnosis (viral or "aseptic" meningitis) and also for elucidating the mechanisms which that underlie the disease pathogenesis/neurological complications.

  15. FDA Bioinformatics Tool for Microbial Genomics Research on Molecular Characterization of Bacterial Foodborne Pathogens Using Microarrays

    Science.gov (United States)

    Background: Advances in microbial genomics and bioinformatics are offering greater insights into the emergence and spread of foodborne pathogens in outbreak scenarios. The Food and Drug Administration (FDA) has developed the genomics tool ArrayTrackTM, which provides extensive functionalities to man...

  16. Bacteriophage remediation of bacterial pathogens in aquaculture: a review of the technology

    Science.gov (United States)

    Bacteriophages have been proposed as an alternative to antibiotic usage and several studies on their application in aquaculture have been reported. This review highlights progress to date on phage therapies for the following fish and shellfish diseases and associated pathogens: hemorrhagic septicem...

  17. The response of the host microcirculation to bacterial sepsis: Does the pathogen matter?

    NARCIS (Netherlands)

    M. Legrand (Matthieu); E. Klijn (Elko); D. Payen (Didier); C. Ince (Can)

    2010-01-01

    textabstractSepsis results from the interaction between a host and an invading pathogen. The microcirculatory dysfunction is now considered central in the development of the often deadly multiple organ dysfunction syndrome in septic shock patients. The microcirculatory flow shutdown and flow shuntin

  18. Mild processing applied to the inactivation of the main foodborne bacterial pathogens

    DEFF Research Database (Denmark)

    Barba Orellana, Francisco Jose; Koubaa, Mohamed; do Prado-Silva, Leonardo

    2017-01-01

    such as high pressure processing, ultrasounds, pulsed electric fields, UV-light, and atmospheric cold plasma may serve, in some conditions, as useful alternatives to commercial sterilization and pasteurization aiming to destroy foodborne pathogens. Each of these mild technologies has a specific mode...

  19. The Clavibacter michiganensis subspecies: molecular investigation of gram-positive bacterial plant pathogens.

    Science.gov (United States)

    Eichenlaub, Rudolf; Gartemann, Karl-Heinz

    2011-01-01

    Clavibacter michiganensis subspecies are actinomycete plant pathogens residing mainly in the xylem vessels that infect economically important host plants. In the Clavibacter subspecies michiganensis and sepedonicus, infecting tomato and potato, respectively, essential factors for disease induction are plasmid encoded and loss of the virulence plasmids converts these biotrophic pathogens into endophytes. The genes responsible for successful colonization of the host plant, including evasion/suppression of plant defense reactions, are chromosomally encoded. Several serine proteases seem to be involved in colonization. They are secreted by Clavibacter, but their targets remain unknown. A type 3 secretion system (T3SS) translocating effectors into the plant cells is absent in these gram-positive pathogens. With the development of the modern 'omics technologies for RNA and proteins based on the known genome sequences, a new phase in the investigation of the mechanisms of plant pathogenicity has begun to allow the genome-wide investigation of the Clavibacter-host interaction. Copyright © 2011 by Annual Reviews. All rights reserved.

  20. “Nothing is permanent but change”* -- Antigenic variation in persistent bacterial pathogens

    OpenAIRE

    Palmer, Guy H.; Bankhead, Troy; Lukehart, Sheila A.

    2009-01-01

    Pathogens persist in immunocompetent mammalian hosts using various strategies, including evasion of immune effectors by antigenic variation. Among highly antigenically variant bacteria, gene conversion is used to generate novel expressed variants from otherwise silent donor sequences. Recombination using oligonucleotide segments from multiple donors is a combinatorial mechanism that tremendously expands the variant repertoire, allowing thousands of variants to be generated from a relatively s...

  1. Quantifying School Officials' Exposure to Bacterial Pathogens at Graduation Ceremonies Using Repeated Observational Measures

    Science.gov (United States)

    Bishai, David; Liu, Liang; Shiau, Stephanie; Wang, Harrison; Tsai, Cindy; Liao, Margaret; Prakash, Shivaani; Howard, Tracy

    2011-01-01

    The purpose of this study was to estimate the risk of acquiring pathogenic bacteria as a result of shaking hands at graduation ceremonies. School officials participating in graduation ceremonies at elementary, secondary, and postsecondary schools were recruited. Specimens were collected before and immediately following graduation. Cultures…

  2. Draft genome sequence of Erwinia tracheiphila, an economically important bacterial pathogen of cucurbits

    Science.gov (United States)

    Erwinia tracheiphila is one of the most economically important pathogen of cucumbers, melons, squashes, pumpkins, and gourds, in the Northeastern and Midwestern United States, yet the molecular pathology remains uninvestigated. Here we report the first draft genome sequence of an E. tracheiphila str...

  3. Diffusible signal factor (DSF) quorum sensing signal and structurally related molecules enhance the antimicrobial efficacy of antibiotics against some bacterial pathogens

    Science.gov (United States)

    2014-01-01

    Background Extensive use of antibiotics has fostered the emergence of superbugs that are resistant to multidrugs, which becomes a great healthcare and public concern. Previous studies showed that quorum sensing signal DSF (diffusible signal factor) not only modulates bacterial antibiotic resistance through intraspecies signaling, but also affects bacterial antibiotic tolerance through interspecies communication. These findings motivate us to exploit the possibility of using DSF and its structurally related molecules as adjuvants to influence antibiotic susceptibility of bacterial pathogens. Results In this study, we have demonstrated that DSF signal and its structurally related molecules could be used to induce bacterial antibiotic susceptibility. Exogenous addition of DSF signal (cis-11-methyl-2-dodecenoic acid) and its structural analogues could significantly increase the antibiotic susceptibility of Bacillus cereus, possibly through reducing drug-resistant activity, biofilm formation and bacterial fitness. The synergistic effect of DSF and its structurally related molecules with antibiotics on B. cereus is dosage-dependent. Combination of DSF with gentamicin showed an obviously synergistic effect on B. cereus pathogenicity in an in vitro model. We also found that DSF could increase the antibiotic susceptibility of other bacterial species, including Bacillus thuringiensis, Staphylococcus aureus, Mycobacterium smegmatis, Neisseria subflava and Pseudomonas aeruginosa. Conclusion The results indicate a promising potential of using DSF and its structurally related molecules as novel adjuvants to conventional antibiotics for treatment of infectious diseases caused by bacterial pathogens. PMID:24575808

  4. Simultaneous Detection of Six Diarrhea-Causing Bacterial Pathogens with an In-House PCR-Luminex Assay

    Science.gov (United States)

    Gratz, Jean; Maro, Athanasia; Kumburu, Happy; Kibiki, Gibson; Taniuchi, Mami; Howlader, Arif Mahmud; Sobuz, Shihab U.; Haque, Rashidul; Talukder, Kaisar A.; Qureshi, Shahida; Zaidi, Anita; Haverstick, Doris M.; Houpt, Eric R.

    2012-01-01

    Diarrhea can be caused by a range of pathogens, including several bacteria. Conventional diagnostic methods, such as culture, biochemical tests, and enzyme-linked immunosorbent assay (ELISA), are laborious. We developed a 7-plex PCR-Luminex assay to simultaneously screen for several of the major diarrhea-causing bacteria directly in fecal specimens, including pathogenic Aeromonas, Campylobacter jejuni, Campylobacter coli, Salmonella, Shigella, enteroinvasive Escherichia coli (EIEC), Vibrio, and Yersinia. We included an extrinsic control to verify extraction and amplification. The assay was first validated with reference strains or isolates and exhibited a limit of detection of 103 to 105 CFU/g of stool for each pathogen as well as quantitative detection up to 109 CFU/g. A total of 205 clinical fecal specimens from individuals with diarrhea, previously cultured for enteric pathogens and tested for Campylobacter by ELISA, were evaluated. Using these predicate methods as standards, sensitivities and specificities of the PCR-Luminex assay were 89% and 94% for Aeromonas, 89% and 93% for Campylobacter, 96% and 95% for Salmonella, 94% and 94% for Shigella, 92% and 97% for Vibrio, and 100% and 100% for Yersinia, respectively. All discrepant results were further examined by singleplex real-time PCR assays targeting different gene regions, which revealed 89% (55/62 results) concordance with the PCR-Luminex assay. The fluorescent signals obtained with this approach exhibited a statistically significant correlation with the cycle threshold (CT) values from the cognate real-time PCR assays (P < 0.05). This multiplex PCR-Luminex assay enables sensitive, specific, and quantitative detection of the major bacterial causes of gastroenteritis. PMID:22075596

  5. Finding immune gene expression differences induced by marine bacterial pathogens in the deep-sea hydrothermal vent mussel Bathymodiolus azoricus

    Directory of Open Access Journals (Sweden)

    R. Bettencourt

    2013-02-01

    Full Text Available The deep-sea hydrothermal vent mussel Bathymodiolus azoricus lives in a natural environment characterized by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea vent biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in vent animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio strains. Flavobacterium suspensions were also used as an irrelevant bacterium. Gene expression analyses were carried out using gill samples from animals dissected at 12 h and 24 h post-infection times by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h and 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the microorganism species inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly around a protein area, of 18 KDa molecular mass, where most dissimilarities were found. Multivariate

  6. Pathogen-Specific Local Immune Fingerprints Diagnose Bacterial Infection in Peritoneal Dialysis Patients

    OpenAIRE

    Lin, Chan-Yu; Roberts, Gareth W.; Kift-Morgan, Ann; Donovan, Kieron L.; Topley, Nicholas; Eberl, Matthias

    2013-01-01

    Accurate and timely diagnosis of bacterial infection is crucial for effective and targeted treatment, yet routine microbiological identification is inefficient and often delayed to an extent that makes it clinically unhelpful. The immune system is capable of a rapid, sensitive and specific detection of a broad spectrum of microbes, which has been optimized over millions of years of evolution. A patient's early immune response is therefore likely to provide far better insight into the true nat...

  7. Surface Proteins of Streptococcus agalactiae and Related Proteins in Other Bacterial Pathogens

    OpenAIRE

    Lindahl, Gunnar; Stålhammar-Carlemalm, Margaretha; Areschoug, Thomas

    2005-01-01

    Streptococcus agalactiae (group B Streptococcus) is the major cause of invasive bacterial disease, including meningitis, in the neonatal period. Although prophylactic measures have contributed to a substantial reduction in the number of infections, development of a vaccine remains an important goal. While much work in this field has focused on the S. agalactiae polysaccharide capsule, which is an important virulence factor that elicits protective immunity, surface proteins have received incre...

  8. Adaptive immunity to Anaplasma pathogens and immune dysregulation: implications for bacterial persistence

    Science.gov (United States)

    Brown, Wendy C.

    2012-01-01

    Anaplasma marginale is an obligate intraerythrocytic bacterium that infects ruminants, and notably causes severe economic losses in cattle worldwide. A. phagocytophilum infects neutrophils and causes disease in many mammals, including ruminants, dogs, cats, horses, and humans. Both bacteria cause persistent infection – infected cattle never clear A. marginale and A. phagocytophilum can also cause persistent infection in ruminants and other animals for several years. This review describes correlates of the protective immune response to these two pathogens as well as subversion and dysregulation of the immune response following infection that likely contribute to long-term persistence. I also compare the immune dysfunction observed with intraerythrocytic A. marginale to that observed in other models of chronic infection resulting in high antigen loads, including malaria, a disease caused by another intraerythrocytic pathogen. PMID:22226382

  9. FGL chaperone-assembled fimbrial polyadhesins: anti-immune armament of Gram-negative bacterial pathogens.

    Science.gov (United States)

    Zavialov, Anton; Zav'yalova, Galina; Korpela, Timo; Zav'yalov, Vladimir

    2007-07-01

    This review summarizes the current knowledge on the structure, function, assembly, and biomedical applications of the family of adhesive fimbrial organelles assembled on the surface of Gram-negative pathogens via the FGL chaperone/usher pathway. Recent studies revealed the unique structural and functional properties of these organelles, distinguishing them from a related family, FGS chaperone-assembled adhesive pili. The FGL chaperone-assembled organelles consist of linear polymers of one or two types of protein subunits, each possessing one or two independent adhesive sites specific to different host cell receptors. This structural organization enables these fimbrial organelles to function as polyadhesins. Fimbrial polyadhesins may ensure polyvalent fastening of bacteria to the host cells, aggregating their receptors and triggering subversive signals that allow pathogens to evade immune defense. The FGL chaperone-assembled fimbrial polyadhesins are attractive targets for vaccine and drug design.

  10. Iron piracy: acquisition of transferrin-bound iron by bacterial pathogens.

    Science.gov (United States)

    Cornelissen, C N; Sparling, P F

    1994-12-01

    The mechanism of iron utilization from transferrin has been most extensively characterized in the pathogenic Neisseria species and Haemophilus species. Two transferrin-binding proteins, Tbp1 and Tbp2, have been identified in these pathogens and are thought to be components of the transferrin receptor. Tbp1 appears to be an integral, TonB-dependent outer membrane protein while Tbp2, a lipoprotein, may be peripherally associated with the outer membrane. The relative contribution of each of these proteins to transferrin binding and utilization is discussed and a model of iron uptake from transferrin is presented. Sequence comparisons of the genes encoding neisserial transferrin-binding proteins suggest that they are probably under positive selection for variation and may have resulted from inter-species genetic exchange.

  11. Microbial Diagnostic Microarrays for the Detection and Typing of Food- and Water-Borne (Bacterial) Pathogens.

    Science.gov (United States)

    Kostić, Tanja; Sessitsch, Angela

    2011-10-14

    Reliable and sensitive pathogen detection in clinical and environmental (including food and water) samples is of greatest importance for public health. Standard microbiological methods have several limitations and improved alternatives are needed. Most important requirements for reliable analysis include: (i) specificity; (ii) sensitivity; (iii) multiplexing potential; (iv) robustness; (v) speed; (vi) automation potential; and (vii) low cost. Microarray technology can, through its very nature, fulfill many of these requirements directly and the remaining challenges have been tackled. In this review, we attempt to compare performance characteristics of the microbial diagnostic microarrays developed for the detection and typing of food and water pathogens, and discuss limitations, points still to be addressed and issues specific for the analysis of food, water and environmental samples.

  12. Microbial Diagnostic Microarrays for the Detection and Typing of Food- and Water-Borne (Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Tanja Kostić

    2011-10-01

    Full Text Available Reliable and sensitive pathogen detection in clinical and environmental (including food and water samples is of greatest importance for public health. Standard microbiological methods have several limitations and improved alternatives are needed. Most important requirements for reliable analysis include: (i specificity; (ii sensitivity; (iii multiplexing potential; (iv robustness; (v speed; (vi automation potential; and (vii low cost. Microarray technology can, through its very nature, fulfill many of these requirements directly and the remaining challenges have been tackled. In this review, we attempt to compare performance characteristics of the microbial diagnostic microarrays developed for the detection and typing of food and water pathogens, and discuss limitations, points still to be addressed and issues specific for the analysis of food, water and environmental samples.

  13. A trip in the "New Microbiology" with the bacterial pathogen Listeria monocytogenes.

    OpenAIRE

    2014-01-01

    International audience; Listeria monocytogenes is a food-borne pathogen causing an opportunistic disease called listeriosis. This bacterium invades and replicates in most cell types, due to its multiple strategies to exploit host molecular mechanisms. Research aiming at unravelling Listeria invasion and intracellular lifestyle has led to a number of key discoveries in infection biology, cell biology and also microbiology. In this review, we report on our most recent advances in understanding ...

  14. Antibacterial activity of different extracts of prawn shell (Macrobrachium nipponense against human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Katayoon Karimzadeh

    2017-01-01

    Full Text Available Aims: Bioactive compounds existing in crustacean shells have the potential to inhibit the growth of some pathogenic microorganism. The purpose of this study is to evaluate the antibacterial effects of different extracts of prawn shells (Macrobrachium nipponense on some human pathogenic bacteria. Materials and Methods: Sampling (prawn was conducted in summer 2014 from Anzali wetland in southern coast of Caspian Sea. Then, the hydroalcoholic, methanolic, and acetone extracts of prawn shells were applied for this purpose. Two Gram-positive (Bacillus subtilis Staphylococcus aureus and three Gram-negative (Klebsiella pneumoniae, Vibrio cholerae, and Escherichia coli were used as test organisms. The antibacterial activity was determined by paper disk diffusion. Results: The prawn shell extracts showed activity against pathogenic bacteria. The highest antibacterial activities were measured in B. subtilis, S. aureus, and V. cholerae with the zone of inhibition being 12.12 ± 0.32 mm, 12.51 ± 0.14 mm, and 12.35 ± 0.27 mm, respectively. Among all the strains, S. aureus exhibits a significant zone of inhibition against all extracts (P < 0.05. Conclusion: The findings of this research showed that different prawn shell extracts, particularly hydroalcoholic, have bactericidal effect on B. subtilis, S. aureus, and V. cholerae species.

  15. Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part II: Vaccines for Shigella, Salmonella, enterotoxigenic E. coli (ETEC) enterohemorragic E. coli (EHEC) and Campylobacter jejuni.

    Science.gov (United States)

    O'Ryan, Miguel; Vidal, Roberto; del Canto, Felipe; Carlos Salazar, Juan; Montero, David

    2015-01-01

    In Part II we discuss the following bacterial pathogens: Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic) and Campylobacter jejuni. In contrast to the enteric viruses and Vibrio cholerae discussed in Part I of this series, for the bacterial pathogens described here there is only one licensed vaccine, developed primarily for Vibrio cholerae and which provides moderate protection against enterotoxigenic E. coli (ETEC) (Dukoral(®)), as well as a few additional candidates in advanced stages of development for ETEC and one candidate for Shigella spp. Numerous vaccine candidates in earlier stages of development are discussed.

  16. Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part II: Vaccines for Shigella, Salmonella, enterotoxigenic E. coli (ETEC) enterohemorragic E. coli (EHEC) and Campylobacter jejuni

    Science.gov (United States)

    O’Ryan, Miguel; Vidal, Roberto; del Canto, Felipe; Carlos Salazar, Juan; Montero, David

    2015-01-01

    In Part II we discuss the following bacterial pathogens: Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic) and Campylobacter jejuni. In contrast to the enteric viruses and Vibrio cholerae discussed in Part I of this series, for the bacterial pathogens described here there is only one licensed vaccine, developed primarily for Vibrio cholerae and which provides moderate protection against enterotoxigenic E. coli (ETEC) (Dukoral®), as well as a few additional candidates in advanced stages of development for ETEC and one candidate for Shigella spp. Numerous vaccine candidates in earlier stages of development are discussed. PMID:25715096

  17. Antibiotic Resistance Pattern Of Bacterial Pathogens Isolated From Poultry Manure Used To Fertilize Fish Ponds In New Bussa, Nigeria

    Directory of Open Access Journals (Sweden)

    Funso Omojowo

    2013-02-01

    Full Text Available This study was carried out to isolate and identify antibiotic resistant bacteria from poultry manure usually used for pond fertilization. Poultry manure from 120 Chickens in National Institute for Freshwater Fisheries Research (NIFFR integrated fish farms, New-Bussa, Nigeria was collected. Five bacterial pathogens; Salmonella typhi, Escherichia coli, Shigella dysenteriae, Staphylococcus aureus and Aeromonas hydrophila were isolated. Antibiotic susceptibility testing carried out using the disk diffusion technique. Antibiotics used were; ofloxacin, amoxicillin, tetracycline, ampicillin, erythromycin, gentamicin, nalidixic acid and chloramphenicol. All the isolated organisms were 100% sensitive to ofloxacin. The multiple resistance pattern revealed that 100% were resistant to tetracycline, 84.34% resistant to ampicillin, 76.68% resistant to amoxicillin, 66% resistant to chloramphenicol, 66% resistant to gentamicin, 29% resistant to erythromycin, 28.34% resistant to nalidixic acid. The risk posed by untreated poultry manure used in fish pond fertilization and the public health implications of these results were discussed.

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

    Science.gov (United States)

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

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

  19. Adhesion of bacterial pathogens to soil colloidal particles: influences of cell type, natural organic matter, and solution chemistry.

    Science.gov (United States)

    Zhao, Wenqiang; Walker, Sharon L; Huang, Qiaoyun; Cai, Peng

    2014-04-15

    Bacterial adhesion to granular soil particles is well studied; however, pathogen interactions with naturally occurring colloidal particles (organic matter (NOM), and solution chemistry. Specifically, batch adhesion experiments were conducted using NOM-present, NOM-stripped soil colloids, Streptococcus suis SC05 and Escherichia coli WH09 over a wide range of solution pH (4.0-9.0) and ionic strength (IS, 1-100 mM KCl). Cell characterization techniques, Freundlich isotherm, and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (sphere-sphere model) were utilized to quantitatively determine the interactions between cells and colloids. The adhesion coefficients (Kf) of S. suis SC05 to NOM-present and NOM-stripped soil colloids were significantly higher than E. coli WH09, respectively. Similarly, Kf values of S. suis SC05 and E. coli WH09 adhesion to NOM-stripped soil colloids were greater than those colloids with NOM-present, respectively, suggesting NOM inhibits bacterial adhesion. Cell adhesion to soil colloids declined with increasing pH and enhanced with rising IS (1-50 mM). Interaction energy calculations indicate these adhesion trends can be explained by DLVO-type forces, with S. suis SC05 and E. coli WH09 being weakly adhered in shallow secondary energy minima via polymer bridging and charge heterogeneity. S. suis SC05 adhesion decreased at higher IS 100 mM, which is attributed to the change of hydrophobic effect and steric repulsion resulted from the greater presence of extracellular polymeric substances (EPS) on S. suis SC05 surface as compared to E. coli WH09. Hence, pathogen adhesion to the colloidal material is determined by a combination of DLVO, charge heterogeneity, hydrophobic and polymer interactions as a function of solution chemistry.

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

    Directory of Open Access Journals (Sweden)

    Mohamed Adam

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

  1. The bacterial pangenome as a new tool for analysing pathogenic bacteria

    OpenAIRE

    L. Rouli; V. Merhej; P.-E. Fournier; Raoult, D

    2015-01-01

    The bacterial pangenome was introduced in 2005 and, in recent years, has been the subject of many studies. Thanks to progress in next-generation sequencing methods, the pangenome can be divided into two parts, the core (common to the studied strains) and the accessory genome, offering a large panel of uses. In this review, we have presented the analysis methods, the pangenome composition and its application as a study of lifestyle. We have also shown that the pangenome may be used as a new to...

  2. Chlamydia psittaci: new insights into genomic diversity, clinical pathology, host-pathogen interaction and anti-bacterial immunity.

    Science.gov (United States)

    Knittler, Michael R; Berndt, Angela; Böcker, Selina; Dutow, Pavel; Hänel, Frank; Heuer, Dagmar; Kägebein, Danny; Klos, Andreas; Koch, Sophia; Liebler-Tenorio, Elisabeth; Ostermann, Carola; Reinhold, Petra; Saluz, Hans Peter; Schöfl, Gerhard; Sehnert, Philipp; Sachse, Konrad

    2014-10-01

    The distinctive and unique features of the avian and mammalian zoonotic pathogen Chlamydia (C.) psittaci include the fulminant course of clinical disease, the remarkably wide host range and the high proportion of latent infections that are not leading to overt disease. Current knowledge on associated diseases is rather poor, even in comparison to other chlamydial agents. In the present paper, we explain and summarize the major findings of a national research network that focused on the elucidation of host-pathogen interactions in vitro and in animal models of C. psittaci infection, with the objective of improving our understanding of genomics, pathology, pathophysiology, molecular pathogenesis and immunology, and conceiving new approaches to therapy. We discuss new findings on comparative genome analysis, the complexity of pathophysiological interactions and systemic consequences, local immune response, the role of the complement system and antigen presentation pathways in the general context of state-of-the-art knowledge on chlamydial infections in humans and animals and single out relevant research topics to fill remaining knowledge gaps on this important yet somewhat neglected pathogen.

  3. Vibrational fingerprinting of bacterial pathogens by surface enhanced Raman scattering (SERS)

    Science.gov (United States)

    Premasiri, W. Ranjith; Moir, D. T.; Ziegler, Lawrence D.

    2005-05-01

    The surface enhanced Raman scattering (SERS) spectra of vegetative whole-cell bacteria were obtained using in-situ grown gold nanoparticle cluster-covered silicon dioxide substrates excited at 785 nm. SERS spectra of Gram-negative bacteria; E. coli and S. typhimurium, and Gram-positive bacteria; B. subtilis, B. cereus, B. thuringeinsis and B. anthracis Sterne, have been observed. Raman enhancement factors of ~104-105 per cell are found for both Gram positive and Gram negative bacteria on this novel SERS substrate. The bacterial SERS spectra are species specific and exhibit greater species differentiation and reduced spectral congestion than their corresponding non-SERS (bulk) Raman spectra. Fluorescence observed in the 785 nm excited bulk Raman emission of Bacillus species is not apparent in the corresponding SERS spectra. The surface enhancement effect allows the observation of Raman spectra at the single cell level excited by low incident laser powers (blood serum, has an observable effect on the bacterial SERS spectra. However, reproducible, species specific SERS vibrational fingerprints are still obtained. The potential of SERS for detection and identification of bacteria with species specificity on these gold nanoparticle coated substrates is demonstrated by these results.

  4. TIR Domain-Containing Adapter-Inducing Beta Interferon (TRIF) Mediates Immunological Memory against Bacterial Pathogens.

    Science.gov (United States)

    Kanagavelu, Saravana; Flores, Claudia; Termini, J M; Romero, Laura; Riveron, Reldy; Ruiz, Jose; Arditi, Moshe; Schesser, Kurt; Fukata, Masayuki

    2015-11-01

    Induction of adaptive immunity leads to the establishment of immunological memory; however, how innate immunity regulates memory T cell function remains obscure. Here we show a previously undefined mechanism in which innate and adaptive immunity are linked by TIR domain-containing adapter-inducing beta interferon (TRIF) during establishment and reactivation of memory T cells against Gram-negative enteropathogens. Absence of TRIF in macrophages (Mϕs) but not dendritic cells led to a predominant generation of CD4(+) central memory T cells that express IL-17 during enteric bacterial infection in mice. TRIF-dependent type I interferon (IFN) signaling in T cells was essential to Th1 lineage differentiation and reactivation of memory T cells. TRIF activated memory T cells to facilitate local neutrophil influx and enhance bacterial elimination. These results highlight the importance of TRIF as a mediator of the innate and adaptive immune interactions in achieving the protective properties of memory immunity against Gram-negative bacteria and suggest TRIF as a potential therapeutic target.

  5. Bacterial biomes and potential human pathogens in irrigation water and leafy greens from different production systems described using pyrosequencing.

    Science.gov (United States)

    Jongman, M; Chidamba, L; Korsten, L

    2017-10-01

    To investigate the influence of irrigation water microbial quality on leafy green vegetables produced in commercial and small-scale farms as well as homestead gardens using pyrosequencing. Next generation sequencing analysis of the V1-V3 hypervariable region of bacterial 16S rDNA was used to compare bacterial diversity in irrigation water sources and on leafy vegetables. In all samples (12) analysed, the phylum Proteobacteria (64·5%), class Gammaproteobacteria (56·6%) and genus Aeromonas (14·4%) were found to be dominant. Of the total Escherichia sequences detected in tested samples, lettuce (16·3%) from the one commercial farm harboured more sequences than cabbage from the small-scale farm (1·3%) or homestead gardens (1·9%). Escherichia sequences were detected in both irrigation water (4·6%) and on cabbage (1·3%) samples from the small-scale farm. The genus Salmonella was absent in borehole water but was detected in the holding dam water (irrigation greatly influences the microbial dynamics of the irrigated crop. Microbial biomes in irrigation water and on leafy greens were described with pyrosequencing and revealed insights into prevalence of potential and opportunistic pathogens across different production systems. © 2017 The Society for Applied Microbiology.

  6. A Two-Tube Multiplex Reverse Transcription PCR Assay for Simultaneous Detection of Viral and Bacterial Pathogens of Infectious Diarrhea

    Directory of Open Access Journals (Sweden)

    Ji Wang

    2014-01-01

    Full Text Available Diarrhea caused by viral and bacterial infections is a major health problem in developing countries. The purpose of this study is to develop a two-tube multiplex PCR assay using automatic electrophoresis for simultaneous detection of 13 diarrhea-causative viruses or bacteria, with an intended application in provincial Centers for Diseases Control and Prevention, China. The assay was designed to detect rotavirus A, norovirus genogroups GI and GII, human astrovirus, enteric adenoviruses, and human bocavirus (tube 1, and Salmonella, Vibrio parahaemolyticus, diarrheagenic Escherichia coli, Campylobacter jejuni, Shigella, Yersinia, and Vibrio cholera (tube 2. The analytical specificity was examined with positive controls for each pathogen. The analytical sensitivity was evaluated by performing the assay on serial tenfold dilutions of in vitro transcribed RNA, recombinant plasmids, or bacterial culture. A total of 122 stool samples were tested by this two-tube assay and the results were compared with those obtained from reference methods. The two-tube assay achieved a sensitivity of 20–200 copies for a single virus and 102-103 CFU/mL for bacteria. The clinical performance demonstrated that the two-tube assay had comparable sensitivity and specificity to those of reference methods. In conclusion, the two-tube assay is a rapid, cost-effective, sensitive, specific, and high throughput method for the simultaneous detection of enteric bacteria and virus.

  7. Universal Probe Library based real-time PCR for rapid detection of bacterial pathogens from positive blood culture bottles.

    Science.gov (United States)

    Zhu, Lingxiang; Shen, Ding-Xia; Zhou, Qiming; Liu, Chao-Jun; Li, Zexia; Fang, Xiangdong; Li, Quan-Zhen

    2014-03-01

    A set of real-time PCR based assays using the locked nucleic acid probes from Roche Universal ProbeLibrary were developed for rapid detection of eight bacterial species from positive blood culture bottles. Four duplex real-time PCR reactions targeting to one Gram-positive bacterium and one Gram-negative bacterium were optimized for species identification according to Gram stain results. We also included mecA-specific primers and probes in the assays to indicate the presence of methicillin resistance in the bacterial species. The analytical sensitivity was in the range of 1-10 CFU per PCR reaction mixture. The specificity and cross reactivity of the assay was validated by 28 ATCC reference strains and 77 negative blood culture specimens. No cross-reactivity was observed in these samples thus demonstrating 100 % specificity. 72 previously characterized clinical isolates were tested by the real-time PCR assay and validated the accuracy and feasibility of the real-time PCR assay. Furthermore, 55 positive blood culture samples were tested using real-time PCR and 50 (90.9 %) of them were identified as the same species as judged by biochemical analysis. In total, real-time PCR showed 98.2 % consistent to that of traditional methods. Real-time PCR can be used as a supplement for early detection of the frequently-occurred pathogens from the positive blood cultures.

  8. Comparative evaluation in the efficacy of peppermint (Mentha piperita) oil with standards antibiotics against selected bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Ebenezer Jeyakumar; Rubina Lawrence; Tripti Pal

    2011-01-01

    Objective: To find the efficacy of peppermint oil against selected bacterial pathogens and compare with their susceptibility towards antibiotics. Methods:Peppermint oil was evaluated for activity against Bacillus cereus, Bacillus subtilis, Escherichia coli, Staphylococcus aureus (S. aureus), Klebsiella pneumoniae and Pseudomonas aeruginosa. The antibacterial assay was evaluated using agar well diffusion method and the viability of the organisms (MIC and MBC) was determined at different concentrations using broth dilution method. Results: Peppermint oil was found to be effective against all the gram positive and gram negative organisms tested. A progressive effect of antibacterial activity with increase in concentration of oil was observed. The test organisms were found to be inhibited by peppermint oil at lower concentration in broth dilution method as compared with agar diffusion method. When comparing the assessment of the inhibitory effect of peppermint oil, broth dilution was found to be more effective as compared with agar diffusion method. Except S. aureus, the remaining organisms tested in the present study were found to possess multiple drug resistance. However, peppermint oil was found to be effective against these bacterial strains studied. Conclusions:Hence, with such broad spectrum activity of peppermint oil, it can be further recommended in the treatment of the infections caused by these multi-drug resistant bacteria.

  9. Identification and characterization of pathogen to bacterial septicaemia in cultured turbot, Scophthalmus maximus

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Bacteria-infected turbots Scophthalmus maximus with septicaemia were examined between 2001 and 2004 in aspects of the conditions of disease occurrence, clinical syndromes and pathological changes. The phenotypic information of pathogenic bacteria was studied, including morphology,physiological and biochemical characteristics, and the mol% G+C of the DNA. In addition, representative strains (S010623-1, LH031120-1) were selected for molecular identification by partial 16S rRNA gene sequencing. The results show that the isolates (LH031120-1 to LH031120-6, HT040308-1 to HT040308-6,HT040620-1 to HT040620-6) from three farms were identified as Edwardsiella tarda. The isolates (S010610-1 to S010610-10, S010623-1 to S010623-20) from one farm were identified as Listonella anguillarum. We conducted studies on the pathogenicity of isolates by artificial infection, and revealed all infected groups in morbidity and mortality. The septicaemia infected turbot showed a syndrome similar to that of the naturally infected fish. Antibiotic sensitivity showed that of 37 antimicrobial agents, E. tarda was sensitive to 27 agents, and L. anguillarum was sensitive to 21 agents.

  10. GATA transcription factor required for immunity to bacterial and fungal pathogens.

    Directory of Open Access Journals (Sweden)

    Samantha Kerry

    Full Text Available In the past decade, Caenorhabditis elegans has been used to dissect several genetic pathways involved in immunity; however, little is known about transcription factors that regulate the expression of immune effectors. C. elegans does not appear to have a functional homolog of the key immune transcription factor NF-kappaB. Here we show that that the intestinal GATA transcription factor ELT-2 is required for both immunity to Salmonella enterica and expression of a C-type lectin gene, clec-67, which is expressed in the intestinal cells and is a good marker of S. enterica infection. We also found that ELT-2 is required for immunity to Pseudomonas aeruginosa, Enterococcus faecalis, and Cryptococcus neoformans. Lack of immune inhibition by DAF-2, which negatively regulates the FOXO transcription factor DAF-16, rescues the hypersusceptibility to pathogens phenotype of elt-2(RNAi animals. Our results indicate that ELT-2 is part of a multi-pathogen defense pathway that regulates innate immunity independently of the DAF-2/DAF-16 signaling pathway.

  11. Genomic epidemiology and global diversity of the emerging bacterial pathogen Elizabethkingia anophelis.

    Science.gov (United States)

    Breurec, Sebastien; Criscuolo, Alexis; Diancourt, Laure; Rendueles, Olaya; Vandenbogaert, Mathias; Passet, Virginie; Caro, Valérie; Rocha, Eduardo P C; Touchon, Marie; Brisse, Sylvain

    2016-07-27

    Elizabethkingia anophelis is an emerging pathogen involved in human infections and outbreaks in distinct world regions. We investigated the phylogenetic relationships and pathogenesis-associated genomic features of two neonatal meningitis isolates isolated 5 years apart from one hospital in Central African Republic and compared them with Elizabethkingia from other regions and sources. Average nucleotide identity firmly confirmed that E. anophelis, E. meningoseptica and E. miricola represent demarcated genomic species. A core genome multilocus sequence typing scheme, broadly applicable to Elizabethkingia species, was developed and made publicly available (http://bigsdb.pasteur.fr/elizabethkingia). Phylogenetic analysis revealed distinct E. anophelis sublineages and demonstrated high genetic relatedness between the African isolates, compatible with persistence of the strain in the hospital environment. CRISPR spacer variation between the African isolates was mirrored by the presence of a large mobile genetic element. The pan-genome of E. anophelis comprised 6,880 gene families, underlining genomic heterogeneity of this species. African isolates carried unique resistance genes acquired by horizontal transfer. We demonstrated the presence of extensive variation of the capsular polysaccharide synthesis gene cluster in E. anophelis. Our results demonstrate the dynamic evolution of this emerging pathogen and the power of genomic approaches for Elizabethkingia identification, population biology and epidemiology.

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

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    Youssef Darzi

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

  13. Low dietary iron intake restrains the intestinal inflammatory response and pathology of enteric infection by food-borne bacterial pathogens.

    Science.gov (United States)

    Kortman, Guus A M; Mulder, Michelle L M; Richters, Thijs J W; Shanmugam, Nanda K N; Trebicka, Estela; Boekhorst, Jos; Timmerman, Harro M; Roelofs, Rian; Wiegerinck, Erwin T; Laarakkers, Coby M; Swinkels, Dorine W; Bolhuis, Albert; Cherayil, Bobby J; Tjalsma, Harold

    2015-09-01

    Orally administrated iron is suspected to increase susceptibility to enteric infections among children in infection endemic regions. Here we investigated the effect of dietary iron on the pathology and local immune responses in intestinal infection models. Mice were held on iron-deficient, normal iron, or high iron diets and after 2 weeks they were orally challenged with the pathogen Citrobacter rodentium. Microbiome analysis by pyrosequencing revealed profound iron- and infection-induced shifts in microbiota composition. Fecal levels of the innate defensive molecules and markers of inflammation lipocalin-2 and calprotectin were not influenced by dietary iron intervention alone, but were markedly lower in mice on the iron-deficient diet after infection. Next, mice on the iron-deficient diet tended to gain more weight and to have a lower grade of colon pathology. Furthermore, survival of the nematode Caenorhabditis elegans infected with Salmonella enterica serovar Typhimurium was prolonged after iron deprivation. Together, these data show that iron limitation restricts disease pathology upon bacterial infection. However, our data also showed decreased intestinal inflammatory responses of mice fed on high iron diets. Thus additionally, our study indicates that the effects of iron on processes at the intestinal host-pathogen interface may highly depend on host iron status, immune status, and gut microbiota composition.

  14. Decreased mortality of lake michigan chinook salmon after bacterial kidney disease challenge: Evidence for pathogen-driven selection?

    Science.gov (United States)

    Purcell, M.K.; Murray, A.L.; Elz, A.; Park, L.K.; Marcquenski, S.V.; Winton, J.R.; Alcorn, S.W.; Pascho, R.J.; Elliott, D.G.

    2008-01-01

    In the late 1960s, Chinook salmon Oncorhynchus tshawytscha from the Green River, Washington, were successfully introduced into Lake Michigan. During spring from1988 to 1992, large fish die-offs affecting Chinook salmon occurred in the lake. Multiple ecological factors probably contributed to the severity of the fish kills, but the only disease agent found regularly was Renibacterium salmoninarum, the causative agent of bacterial kidney disease. in this study, survival after challenge by R. salmoninarum was compared between two Chinook salmon stocks: a Lake Michigan stock from Wisconsin (WI) and the progenitor stock from the Green River. We found that the WI stock had significantly greater survival than the Green River stock. Next, the WI and Green River stocks were exposed to the marine pathogen Listonella anguillarum (formerly Vibrio anguillarum), one of the causative agents of vibriosis; survival after this challenge was significantly poorer for the WI stock than for the Green River stock. A close genetic relationship between the Green River and WI stocks was confirmed by analyzing 13 microsatellite loci. These results collectively suggest that disease susceptibility of Lake Michigan Chinook salmon has diverged from that of the source population, possibly in response to pathogen-driven selection. ?? Copyright by the American Fisheries Society 2008.

  15. In vitro effectiveness of the antimicrobial peptide eCATH1 against antibiotic-resistant bacterial pathogens of horses.

    Science.gov (United States)

    Schlusselhuber, Margot; Guldbech, Kristen; Sevin, Corinne; Leippe, Matthias; Petry, Sandrine; Grötzinger, Joachim; Giguère, Steeve; Cauchard, Julien

    2014-01-01

    The equine antimicrobial peptide eCATH1 previously has been shown to have in vitro activity against antibiotic-susceptible reference strains of Rhodococcus equi and common respiratory bacterial pathogens of foals. Interestingly, eCATH1 was also found to be effective in the treatment of R. equi infection induced in mice. The aim of this study was to assess the in vitro activity of eCATH1 against equine isolates of Gram-negative (Escherichia coli, Salmonella enterica, Klebsiella pneumoniae and Pseudomonas spp.) and Gram-positive (R. equi, Staphylococcus aureus) bacteria resistant to multiple classes of conventional antibiotics. A modified microdilution method was used to evaluate the minimum inhibitory concentrations (MICs) of the antimicrobial peptide. The study revealed that eCATH1 was active against all equine isolates of E. coli, S. enterica, K. pneumoniae, Pseudomonas spp. and R. equi tested, with MICs of 0.5-16 μg mL(-1), but was not active against most isolates of S. aureus. In conclusion, the activity of the equine antimicrobial peptide eCATH1 appears to not be hampered by the antibiotic resistance of clinical isolates. Thus, the data suggest that eCATH1 could be useful, not only in the treatment of R. equi infections, but also of infections caused by multidrug-resistant Gram-negative pathogens.

  16. A Novel Mechanism of Host-Pathogen Interaction through sRNA in Bacterial Outer Membrane Vesicles.

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    Katja Koeppen

    2016-06-01

    Full Text Available Bacterial outer membrane vesicle (OMV-mediated delivery of proteins to host cells is an important mechanism of host-pathogen communication. Emerging evidence suggests that OMVs contain differentially packaged short RNAs (sRNAs with the potential to target host mRNA function and/or stability. In this study, we used RNA-Seq to characterize differentially packaged sRNAs in Pseudomonas aeruginosa OMVs, and to show transfer of OMV sRNAs to human airway cells. We selected one sRNA for further study based on its stable secondary structure and predicted mRNA targets. Our candidate sRNA (sRNA52320, a fragment of a P. aeruginosa methionine tRNA, was abundant in OMVs and reduced LPS-induced as well as OMV-induced IL-8 secretion by cultured primary human airway epithelial cells. We also showed that sRNA52320 attenuated OMV-induced KC cytokine secretion and neutrophil infiltration in mouse lung. Collectively, these findings are consistent with the hypothesis that sRNA52320 in OMVs is a novel mechanism of host-pathogen interaction whereby P. aeruginosa reduces the host immune response.

  17. 草莓细菌叶斑病病原鉴定%Bacterial Pathogen Identification of Leaf Spot on Strawberry

    Institute of Scientific and Technical Information of China (English)

    米楠

    2011-01-01

    Traditional bacterial identification measures by appearance observation and physiology bio-chemical tests and the mordern bacterial identification measures by 16S rDNA technique were used to identify the bacterial pathogen of leaf spot on strawberry. The results showed that the strain could use glucose,lactose,maltose,sucrose,D-Trehalose,starch,mannitol,inositol,L-Valine and L-Proline. The strain was positive for nitrate reduction, arginine cihydrolase and oxidase reaction,but negative for fat hydrolysis,starch hydrolysis and gelatin hydrolysis. At last,the strain was identified as Xanthomonas fragariae.%采用形态观察、生理生化特性测试等传统的细菌鉴定方法和16srDNA碱基序列测定等现代的细菌鉴定方法鉴定草莓细菌叶斑病菌株。结果表明:该菌株可利用的碳源有葡萄糖、乳糖、麦芽糖、蔗糖、D-海藻糖、淀粉、甘露醇、肌醇、L-缬氨酸、L-精氨酸。硝酸盐还原试验为阳性,淀粉水解阴性,明胶水解阴性,油脂水解阴性,精氨酸双水解酶阳性,接触酶阳性;鉴定该菌株为草莓黄单孢菌(Xanthomonas fragariae)。

  18. Impact of urbanization and agriculture on the occurrence of bacterial pathogens and stx genes in coastal waterbodies of central California.

    Science.gov (United States)

    Walters, Sarah P; Thebo, Anne L; Boehm, Alexandria B

    2011-02-01

    Fecal pollution enters coastal waters through multiple routes, many of which originate from land-based activities. Runoff from pervious and impervious land surfaces transports pollutants from land to sea and can cause impairment of coastal ocean waters. To understand how land use practices and water characteristics influence concentrations of fecal indicator bacteria (FIB) and pathogens in natural waters, fourteen coastal streams, rivers, and tidal lagoons, surrounded by variable land use and animal densities, were sampled every six weeks over two years (2008 & 2009). Fecal indicator bacteria (FIB; Escherichia coli and Enterococci) and Salmonella concentrations, the occurrence of Bacteroidales human, ruminant, and pig-specific fecal markers, E. coli O157:H7, and Shiga toxin (stx) genes present in E. coli, were measured. In addition, environmental and climatic variables (e.g., temperature, salinity, rainfall), as well as human and livestock population densities and land cover were quantified. Concentrations of FIB and Salmonella were correlated with each other, but the occurrence of host-specific Bacteroidales markers did not correlate with FIB or pathogens. FIB and Salmonella concentrations, as well as the occurrence of E. coli harboring stx genes, were positively associated with the fraction of the surrounding subwatershed that was urban, while the occurrence of E. coli O157:H7 was positively associated with the agricultural fraction. FIB and Salmonella concentrations were negatively correlated to salinity and temperature, and positively correlated to rainfall. Areal loading rates of FIB, Salmonella and E. coli O157:H7 to the coastal ocean were calculated for stream and river sites and varied with land cover, salinity, temperature, and rainfall. Results suggest that FIB and pathogen concentrations are influenced, in part, by their flux from the land, which is exacerbated during rainfall; once waterborne, bacterial persistence is affected by water temperature and

  19. Using weakly conserved motifs hidden in secretion signals to identify type-III effectors from bacterial pathogen genomes.

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    Xiaobao Dong

    Full Text Available BACKGROUND: As one of the most important virulence factor types in gram-negative pathogenic bacteria, type-III effectors (TTEs play a crucial role in pathogen-host interactions by directly influencing immune signaling pathways within host cells. Based on the hypothesis that type-III secretion signals may be comprised of some weakly conserved sequence motifs, here we used profile-based amino acid pair information to develop an accurate TTE predictor. RESULTS: For a TTE or non-TTE, we first used a hidden Markov model-based sequence searching method (i.e., HHblits to detect its weakly homologous sequences and extracted the profile-based k-spaced amino acid pair composition (HH-CKSAAP from the N-terminal sequences. In the next step, the feature vector HH-CKSAAP was used to train a linear support vector machine model, which we designate as BEAN (Bacterial Effector ANalyzer. We compared our method with four existing TTE predictors through an independent test set, and our method revealed improved performance. Furthermore, we listed the most predictive amino acid pairs according to their weights in the established classification model. Evolutionary analysis shows that predictive amino acid pairs tend to be more conserved. Some predictive amino acid pairs also show significantly different position distributions between TTEs and non-TTEs. These analyses confirmed that some weakly conserved sequence motifs may play important roles in type-III secretion signals. Finally, we also used BEAN to scan one plant pathogen genome and showed that BEAN can be used for genome-wide TTE identification. The webserver and stand-alone version of BEAN are available at http://protein.cau.edu.cn:8080/bean/.

  20. Exploration and conservation of bacterial genetic resources as bacteriocin producing inhibitory microorganisms to pathogen bacteria in livestock

    Directory of Open Access Journals (Sweden)

    Chotiah S

    2013-06-01

    Full Text Available Exploration and conservation of microorganisms producing bacteriocin was done as the primary study towards the collection of potential bacteria and its application in improving livestock health condition and inhibit food borne pathogens. Diferent kinds of samples such as beef cattle rectal swab, rumen fluids, cow’s milk, chicken gut content, goat’s milk were collected at Bogor cattle slaughter houses, poultry slaughter houses, dairy cattle and goat farms. A total of 452 bacterial isolates consisted of 73 Gram negative bacteria and 379 Gram positive bacteria were isolated from samples collected and screened for bacteriocin activity. Determination of bacteriocin activity with bioassay using agar spot tests were carried out on liquid and semisolid medium assessing 8 kins of indicators of pathogenic bacteria and food borne pathogens. A total of 51 bacteriocin producing strains were collected and some of the strains had high inhibitory zone such as Lactobacillus casei SS14C (26 mm, Enterobacter cloacae SRUT (24mm, Enterococcus faecalis SK39 (21mm and Bifidobacterium dentium SS14T (20mm respectively, to Salmonella typhimurium BCC B0046/ATCC 13311, E. coli O157 hemolytic BCC B2717, Listeria monocytogenes BCC B2767/ATCC 7764 and Escherichia coli VTEC O157 BCC B2687. Evaluation after conservation ex situ to all bacterocin producing strain at 5oC for 1 year in freeze drying ampoules in vacuum and dry condition revealed the decreasing viability starting from log 0.8 CFU/ml for Lactococcus and Leuconostoc to log 2.2. CFU/ml for Streptococcus. Result of the study showed that the bacteriocin producing strains obtained were offered a potential resource for preventing disease of livestock and food borne diseases.

  1. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002-2004.

    Science.gov (United States)

    Hendriksen, Rene S; Mevius, Dik J; Schroeter, Andreas; Teale, Christopher; Meunier, Danièle; Butaye, Patrick; Franco, Alessia; Utinane, Andra; Amado, Alice; Moreno, Miguel; Greko, Christina; Stärk, Katharina; Berghold, Christian; Myllyniemi, Anna-Liisa; Wasyl, Dariusz; Sunde, Marianne; Aarestrup, Frank M

    2008-07-08

    The project "Antibiotic resistance in bacteria of animal origin - II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003-2005, with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected. Antimicrobial susceptibility data for several bovine pathogens were obtained over a three year period (2002-2004). Each year the participating laboratories were requested to fill in excel-file templates with national summary data on the occurrence of antimicrobial resistance from different bacterial species.A proficiency test (EQAS - external quality assurance system) for antimicrobial susceptibility testing was conducted each year to test the accuracy of antimicrobial susceptibility testing in the participating laboratories. The data from this testing demonstrated that for the species included in the EQAS the results are comparable between countries. Data from 25,241 isolates were collected from 13 European countries. For Staphylococcus aureus from bovine mastitis major differences were apparent in the occurrence of resistance between countries and between the different antimicrobial agents tested. The highest frequency of resistance was observed for penicillin. For Mannheimia haemolytica resistance to ampicillin, tetracycline and trimethoprim/sulphonamide were observed in France, the Netherlands and Portugal. All isolates of Pasteurella multocida isolated in Finland and most of those from Denmark, England (and Wales), Italy and Sweden were susceptible to the majority of the antimicrobials. Streptococcus dysgalactiae and Streptococcus uberis isolates from Sweden were fully susceptible. For the other countries some resistance was observed to tetracycline, gentamicin and erythromycin. More resistance

  2. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004

    Directory of Open Access Journals (Sweden)

    Stärk Katharina

    2008-07-01

    Full Text Available Abstract Background The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II was funded by the European Union (FAIR5-QLK2-2002-01146 for the period 2003–2005, with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected. Method Antimicrobial susceptibility data for several bovine pathogens were obtained over a three year period (2002–2004. Each year the participating laboratories were requested to fill in excel-file templates with national summary data on the occurrence of antimicrobial resistance from different bacterial species. A proficiency test (EQAS – external quality assurance system for antimicrobial susceptibility testing was conducted each year to test the accuracy of antimicrobial susceptibility testing in the participating laboratories. The data from this testing demonstrated that for the species included in the EQAS the results are comparable between countries. Results Data from 25,241 isolates were collected from 13 European countries. For Staphylococcus aureus from bovine mastitis major differences were apparent in the occurrence of resistance between countries and between the different antimicrobial agents tested. The highest frequency of resistance was observed for penicillin. For Mannheimia haemolytica resistance to ampicillin, tetracycline and trimethoprim/sulphonamide were observed in France, the Netherlands and Portugal. All isolates of Pasteurella multocida isolated in Finland and most of those from Denmark, England (and Wales, Italy and Sweden were susceptible to the majority of the antimicrobials. Streptococcus dysgalactiae and Streptococcus uberis isolates from Sweden were fully susceptible. For the other countries some resistance was observed to

  3. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004

    Science.gov (United States)

    Hendriksen, Rene S; Mevius, Dik J; Schroeter, Andreas; Teale, Christopher; Meunier, Danièle; Butaye, Patrick; Franco, Alessia; Utinane, Andra; Amado, Alice; Moreno, Miguel; Greko, Christina; Stärk, Katharina; Berghold, Christian; Myllyniemi, Anna-Liisa; Wasyl, Dariusz; Sunde, Marianne; Aarestrup, Frank M

    2008-01-01

    Background The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003–2005, with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected. Method Antimicrobial susceptibility data for several bovine pathogens were obtained over a three year period (2002–2004). Each year the participating laboratories were requested to fill in excel-file templates with national summary data on the occurrence of antimicrobial resistance from different bacterial species. A proficiency test (EQAS – external quality assurance system) for antimicrobial susceptibility testing was conducted each year to test the accuracy of antimicrobial susceptibility testing in the participating laboratories. The data from this testing demonstrated that for the species included in the EQAS the results are comparable between countries. Results Data from 25,241 isolates were collected from 13 European countries. For Staphylococcus aureus from bovine mastitis major differences were apparent in the occurrence of resistance between countries and between the different antimicrobial agents tested. The highest frequency of resistance was observed for penicillin. For Mannheimia haemolytica resistance to ampicillin, tetracycline and trimethoprim/sulphonamide were observed in France, the Netherlands and Portugal. All isolates of Pasteurella multocida isolated in Finland and most of those from Denmark, England (and Wales), Italy and Sweden were susceptible to the majority of the antimicrobials. Streptococcus dysgalactiae and Streptococcus uberis isolates from Sweden were fully susceptible. For the other countries some resistance was observed to tetracycline

  4. Making healthier or killing enemies? Bacterial volatile-elicited plant immunity plays major role upon protection of Arabidopsis than the direct pathogen inhibition.

    Science.gov (United States)

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Bacterial volatiles protect plants either by directly inhibiting a pathogenic fungus or by improving the defense capabilities of plants. The effect of bacterial volatiles on fungal growth was dose-dependent. A low dosage did not have a noticeable effect on Botrytis cinerea growth and development, but was sufficient to elicit induced resistance in Arabidopsis thaliana. Bacterial volatiles displayed negative effects on biofilm formation on a polystyrene surface and in in planta leaf colonization of B. cinerea. However, bacterial volatile-mediated induced resistance was the major mechanism mediating protection of plants from B. cinerea. It was responsible for more than 90% of plant protection in comparison with direct fungal inhibition. Our results broaden our knowledge of the role of bacterial volatiles in plant protection.

  5. [Microbiological diagnosis of emerging bacterial pathogens: Anaplasma, Bartonella, Rickettsia, and Tropheryma whipplei].

    Science.gov (United States)

    Blanco, José Ramón; Jado, Isabel; Marín, Mercedes; Sanfeliu, Isabel; Portillo, Aránzazu; Anda, Pedro; Pons, Immaculada; Oteo, José Antonio

    2008-11-01

    Ehrlichia/Anaplasma, Bartonella, Rickettsia and Tropheryma whipplei (formerly called whippelii) are fastidious bacterial organisms, considered the causative agents of potentially severe emerging and re-emerging diseases with repercussions on public health. The recent availability of advanced molecular biology and cell culture techniques has led to the implication of many of these species in human pathologies. These issues are extensively covered in number 27 of the SEIMC microbiological procedure: Diagnóstico microbiológico de las infecciones por patógenos bacterianos emergentes: Anaplasma, Bartonella, Rickettsia y Tropheryma whippelii (Microbiological diagnosis of Anaplasma, Bartonella, Rickettsia and Tropheryma whippelii infections) (2nd ed., 2007) (www.seimc.org/documentos/protocolos/microbiologia/).

  6. One third of middle ear effusions from children undergoing tympanostomy tube placement had multiple bacterial pathogens

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    Holder Robert C

    2012-06-01

    Full Text Available Abstract Background Because previous studies have indicated that otitis media may be a polymicrobial disease, we prospectively analyzed middle ear effusions of children undergoing tympanostomy tube placement with multiplex polymerase chain reaction for four otopathogens. Methods Middle ear effusions from 207 children undergoing routine tympanostomy tube placement were collected and were classified by the surgeon as acute otitis media (AOM for purulent effusions and as otitis media with effusion (OME for non-purulent effusions. DNA was isolated from these samples and analyzed with multiplex polymerase chain reaction for Haemophilus influenzae, Streptococcus pneumoniae, Alloiococcus otitidis, and Moraxella catarrhalis. Results 119 (57% of 207 patients were PCR positive for at least one of these four organisms. 36 (30% of the positive samples indicated the presence of more than one bacterial species. Patient samples were further separated into 2 groups based on clinical presentation at the time of surgery. Samples were categorized as acute otitis media (AOM if pus was observed behind the tympanic membrane. If no pus was present, samples were categorized as otitis media with effusion (OME. Bacteria were identified in most of the children with AOM (87% and half the children with OME (51%, p Haemophilus influenzae was the predominant single organism and caused 58% of all AOM in this study. Alloiococcus otitidis and Moraxella catarrhalis were more frequently identified in middle ear effusions than Streptococcus pneumoniae. Conclusions Haemophilus influenzae, Streptococcus pneumoniae, Alloiococcus otitidis, and Moraxella catarrhalis were identified in the middle ear effusions of some patients with otitis media. Overall, we found AOM is predominantly a single organism infection and most commonly from Haemophilus influenzae. In contrast, OME infections had a more equal distribution of single organisms, polymicrobial entities, and non-bacterial agents.

  7. Anti-infective effects of Brazilian Caatinga plants against pathogenic bacterial biofilm formation.

    Science.gov (United States)

    Silva, Laura Nunes; Trentin, Danielle da Silva; Zimmer, Karine Rigon; Treter, Janine; Brandelli, Clara Lia Costa; Frasson, Amanda Piccoli; Tasca, Tiana; da Silva, Alexandre Gomes; da Silva, Márcia Vanusa; Macedo, Alexandre José

    2015-03-01

    The local communities living in the Brazilian Caatinga biome have a significant body of traditional knowledge on a considerable number of medicinal plants used to heal several maladies. Based on ethnopharmacological data, this study screened 23 aqueous plant extracts against two well-known models of biofilm-forming bacteria: Staphylococcus epidermidis and Pseudomonas aeruginosa. Crystal violet assay and scanning electron microscopy (SEM) were used to evaluate the effect of extracts on biofilm formation and measurements of the absorbance at 600 nm to assess bacterial growth. Selected extracts were investigated regarding the cytotoxicity by MTT assay using mammal cells and the qualitative phytochemical fingerprint by thin layer chromatography. Harpochilus neesianus Mart. ex Nees. (Acanthaceae) leaves, Apuleia leiocarpa Vogel J. F. Macbr. (Fabaceae), and Poincianella microphylla Mart. ex G. Don L. P. Queiroz (Fabaceae) fruits showed non-biocidal antibiofilm action against S. epidermidis with activities of 69, 52, and 63%, respectively. SEM confirmed that biofilm structure was strongly prevented and that extracts promoted overproduction of the matrix and/or bacterial morphology modification. Poincianella microphylla demonstrated toxicity at 4.0 mg/mL and 2.0 mg/mL, A. leiocarpa presented toxicity only at 4.0 mg/mL, whereas H. neesianus presented the absence of toxicity against Vero cell line. Preliminary phytochemical analysis revealed the presence of flavonoids, terpenoids, steroids, amines, and polyphenols. This work provides a scientific basis which may justify the ethnopharmacological use of the plants herein studied, indicating extracts that possess limited mammal cytotoxicity in vitro and a high potential as a source of antibiofilm drugs prototypes.

  8. The sensitivity of bacterial foodborne pathogens to Croton blanchetianus Baill essential oil

    Directory of Open Access Journals (Sweden)

    Geiseanny Fernandes do Amarante Melo

    2013-12-01

    Full Text Available The aim of this study was to assess the activity of essential oil extracted from the leaves of C. blanchetianus Baill, popularly known as "marmeleiro", in inhibiting the growth and survival of pathogenic microorganisms in food by determining their survival in vitro and by observing the behaviour of Listeria monocytogenes inoculated into a food model (meat cubes that was stored at refrigeration temperature (7 ± 1 ºC for 4 days. The results indicated a bactericidal effect against Aeromonas hydrophila and Listeria monocytogenes and bacteriostatic action against Salmonella Enteritidis. A bacteriostatic effect on meat contaminated with L. monocytogenes was found for all concentrations of essential oils tested. These results showed that essential oil from the leaves of C. blanchetianus Baill represents an alternative source of potentially natural antimicrobial agents that may be used as a food preservative.

  9. Salvage microbiology: opportunities and challenges in the detection of bacterial pathogens following initiation of antimicrobial treatment

    Science.gov (United States)

    Farrell, John J.; Hujer, Andrea M.; Sampath, Rangarajan; Bonomo, Robert A.

    2015-01-01

    Broad-range 16S ribosomal RNA gene PCR coupled with Sanger sequencing was originally employed by soil scientists and was subsequently adapted for clinical applications. PCR coupled with electrospray ionization mass spectrometry has also progressed from initial applications in the detection of organisms from environmental samples into the clinical realm and has demonstrated promise in detection of pathogens in clinical specimens obtained from patients with suspected infection but negative cultures. We review studies of multiplex PCR, 16S ribosomal RNA gene PCR and sequencing and PCR coupled with electrospray ionization mass spectrometry for detection of bacteria in specimens that were obtained from patients during or after administration of antibiotic treatment, and examine the role of each for assisting in antimicrobial treatment and stewardship efforts. Following an exploration of the available data in this field we discuss the opportunities that the preliminary investigations reveal, as well as the challenges faced with implementation of these strategies in clinical practice. PMID:25523281

  10. The sensitivity of bacterial foodborne pathogens to Croton blanchetianus Baill essential oil

    Science.gov (United States)

    do Amarante Melo, Geiseanny Fernandes; da Costa, Ana Caroliny Vieira; Garino, Felício; Medeiros, Rosália Severo; Madruga, Marta Suely; Neto, Vicente Queiroga

    2013-01-01

    The aim of this study was to assess the activity of essential oil extracted from the leaves of C. blanchetianus Baill, popularly known as “marmeleiro”, in inhibiting the growth and survival of pathogenic microorganisms in food by determining their survival in vitro and by observing the behaviour of Listeria monocytogenes inoculated into a food model (meat cubes) that was stored at refrigeration temperature (7 ± 1 °C) for 4 days. The results indicated a bactericidal effect against Aeromonas hydrophila and Listeria monocytogenes and bacteriostatic action against Salmonella Enteritidis. A bacteriostatic effect on meat contaminated with L. monocytogenes was found for all concentrations of essential oils tested. These results showed that essential oil from the leaves of C. blanchetianus Baill represents an alternative source of potentially natural antimicrobial agents that may be used as a food preservative. PMID:24688510

  11. The sensitivity of bacterial foodborne pathogens to Croton blanchetianus Baill essential oil.

    Science.gov (United States)

    do Amarante Melo, Geiseanny Fernandes; da Costa, Ana Caroliny Vieira; Garino Junior, Felício; Medeiros, Rosália Severo; Madruga, Marta Suely; Queiroga Neto, Vicente

    2013-12-01

    The aim of this study was to assess the activity of essential oil extracted from the leaves of C. blanchetianus Baill, popularly known as "marmeleiro", in inhibiting the growth and survival of pathogenic microorganisms in food by determining their survival in vitro and by observing the behaviour of Listeria monocytogenes inoculated into a food model (meat cubes) that was stored at refrigeration temperature (7 ± 1 °C) for 4 days. The results indicated a bactericidal effect against Aeromonas hydrophila and Listeria monocytogenes and bacteriostatic action against Salmonella Enteritidis. A bacteriostatic effect on meat contaminated with L. monocytogenes was found for all concentrations of essential oils tested. These results showed that essential oil from the leaves of C. blanchetianus Baill represents an alternative source of potentially natural antimicrobial agents that may be used as a food preservative.

  12. Molecular detection of bacterial and parasitic pathogens in hard ticks from Portugal.

    Science.gov (United States)

    Maia, Carla; Ferreira, Andreia; Nunes, Mónica; Vieira, Maria Luísa; Campino, Lenea; Cardoso, Luís

    2014-06-01

    Ticks are important vector arthropods of human and animal pathogens. As information about agents of disease circulating in vectors in Portugal is limited, the aim of the present study was to detect bacteria and parasites with veterinary and zoonotic importance in ticks collected from dogs, cats, and field vegetation. A total of 925 ticks, comprising 888 (96.0%) adults, 8 (0.9%) nymphs, and 29 (3.1%) larvae, were collected in 4 geographic areas (districts) of Portugal. Among those, 620 (67.0%) were removed from naturally infested dogs, 42 (4.5%) from cats, and 263 (28.4%) were questing ticks obtained from field vegetation. Rhipicephalus sanguineus was the predominant tick species, and the only one collected from dogs and vegetation, while all Ixodes ricinus specimens (n=6) were recovered from cats. Rickettsia massiliae and Rickettsia conorii were identified in 35 ticks collected from cats and dogs and in 3 ticks collected from dogs. Among ticks collected from cats or dogs, 4 Rh. sanguineus specimens were detected with Hepatozoon felis, 3 with Anaplasma platys, 2 with Hepatozoon canis, one with Anaplasma phagocytophilum, one with Babesia vogeli, one with Borrelia burgdorferi sensu lato and one with Cercopithifilaria spp. Rickettsia helvetica was detected in one I. ricinus tick collected from a cat. To the best of our knowledge, this was the first time that Cercopithifilaria spp., Ba. vogeli, H. canis, and H. felis have been detected in ticks from Portugal. The wide range of tick-borne pathogens identified, some of zoonotic concern, suggests a risk for the emergence of tick-borne diseases in domestic animals and humans in Portugal. Further studies on these and other tick-borne agents should be performed to better understand their epidemiological and clinical importance, and to support the implementation of effective control measures.

  13. The landscape of host transcriptional response programs commonly perturbed by bacterial pathogens: towards host-oriented broad-spectrum drug targets.

    Science.gov (United States)

    Kidane, Yared H; Lawrence, Christopher; Murali, T M

    2013-01-01

    The emergence of drug-resistant pathogen strains and new infectious agents pose major challenges to public health. A promising approach to combat these problems is to target the host's genes or proteins, especially to discover targets that are effective against multiple pathogens, i.e., host-oriented broad-spectrum (HOBS) drug targets. An important first step in the discovery of such drug targets is the identification of host responses that are commonly perturbed by multiple pathogens. In this paper, we present a methodology to identify common host responses elicited by multiple pathogens. First, we identified host responses perturbed by each pathogen using a gene set enrichment analysis of publicly available genome-wide transcriptional datasets. Then, we used biclustering to identify groups of host pathways and biological processes that were perturbed only by a subset of the analyzed pathogens. Finally, we tested the enrichment of each bicluster in human genes that are known drug targets, on the basis of which we elicited putative HOBS targets for specific groups of bacterial pathogens. We identified 84 up-regulated and three down-regulated statistically significant biclusters. Each bicluster contained a group of pathogens that commonly dysregulated a group of biological processes. We validated our approach by checking whether these biclusters correspond to known hallmarks of bacterial infection. Indeed, these biclusters contained biological process such as inflammation, activation of dendritic cells, pro- and anti- apoptotic responses and other innate immune responses. Next, we identified biclusters containing pathogens that infected the same tissue. After a literature-based analysis of the drug targets contained in these biclusters, we suggested new uses of the drugs Anakinra, Etanercept, and Infliximab for gastrointestinal pathogens Yersinia enterocolitica, Helicobacter pylori kx2 strain, and enterohemorrhagic Escherichia coli and the drug Simvastatin for

  14. The landscape of host transcriptional response programs commonly perturbed by bacterial pathogens: towards host-oriented broad-spectrum drug targets.

    Directory of Open Access Journals (Sweden)

    Yared H Kidane

    Full Text Available BACKGROUND: The emergence of drug-resistant pathogen strains and new infectious agents pose major challenges to public health. A promising approach to combat these problems is to target the host's genes or proteins, especially to discover targets that are effective against multiple pathogens, i.e., host-oriented broad-spectrum (HOBS drug targets. An important first step in the discovery of such drug targets is the identification of host responses that are commonly perturbed by multiple pathogens. RESULTS: In this paper, we present a methodology to identify common host responses elicited by multiple pathogens. First, we identified host responses perturbed by each pathogen using a gene set enrichment analysis of publicly available genome-wide transcriptional datasets. Then, we used biclustering to identify groups of host pathways and biological processes that were perturbed only by a subset of the analyzed pathogens. Finally, we tested the enrichment of each bicluster in human genes that are known drug targets, on the basis of which we elicited putative HOBS targets for specific groups of bacterial pathogens. We identified 84 up-regulated and three down-regulated statistically significant biclusters. Each bicluster contained a group of pathogens that commonly dysregulated a group of biological processes. We validated our approach by checking whether these biclusters correspond to known hallmarks of bacterial infection. Indeed, these biclusters contained biological process such as inflammation, activation of dendritic cells, pro- and anti- apoptotic responses and other innate immune responses. Next, we identified biclusters containing pathogens that infected the same tissue. After a literature-based analysis of the drug targets contained in these biclusters, we suggested new uses of the drugs Anakinra, Etanercept, and Infliximab for gastrointestinal pathogens Yersinia enterocolitica, Helicobacter pylori kx2 strain, and enterohemorrhagic Escherichia

  15. Evaluation of the Seeplex® Meningitis ACE Detection kit for the detection of 12 common bacterial and viral pathogens of acute meningitis.

    Science.gov (United States)

    Shin, So Youn; Kwon, Kye Chul; Park, Jong Woo; Kim, Ji Myung; Shin, So Young; Koo, Sun Hoe

    2012-01-01

    Bacterial meningitis is an infectious disease with high rates of mortality and high frequency of severe sequelae. Early identification of causative bacterial and viral pathogens is important for prompt and proper treatment of meningitis and for prevention of life-threatening clinical outcomes. In the present study, we evaluated the value of the Seeplex Meningitis ACE Detection kit (Seegene Inc., Korea), a newly developed multiplex PCR kit employing dual priming oligonucleotide methods, for diagnosing acute meningitis. Analytical sensitivity of the kit was studied using reference strains for each pathogen targeted by the kit, while it's analytical specificity was studied using the human genome DNA and 58 clinically well-identified reference strains. For clinical validation experiment, we used 27 control cerebrospinal fluid (CSF) samples and 78 clinical CSF samples collected from patients at the time of diagnosis of acute meningitis. The lower detection limits ranged from 10(1) copies/µL to 5×10(1) copies/µL for the 12 viral and bacterial pathogens targeted. No cross-reaction was observed. In the validation study, high detection rate of 56.4% was obtained. None of the control samples tested positive, i.e., false-positive results were absent. The Seeplex Meningitis ACE Detection kit showed high sensitivity, specificity, and detection rate for the identification of pathogens in clinical CSF samples. This kit may be useful for rapid identification of important acute meningitis-causing pathogens.

  16. Detection of respiratory viral and bacterial pathogens causing pediatric community-acquired pneumonia in Beijing using real-time PCR

    Institute of Scientific and Technical Information of China (English)

    Tie-Gang Zhang; Ai-Hua Li; Min Lyu; Meng Chen; Fang Huang; Jiang Wu

    2015-01-01

    Objective: The aim of this study was to determine the etiology and prevalence of pediatric CAP in Beijing using a real-time polymerase chain reaction (PCR) technique. Methods: Between February 15, 2011 and January 18, 2012, 371 pediatric patients with CAP were enrolled at Beijing Children's Hospital. Sixteen respiratory viruses and two bacteria were detected from tracheal aspirate specimens using commercially available multiplex real-time reverse transcription PCR (RT-PCR) kits. Results: A single viral pathogen was detected in 35.3%of enrolled patients, multiple viruses in 11.6%, and virus/bacteria co-infection in 17.8%. In contrast, only 6.5%of patients had a single bacterial pathogen and 2.2%were infected with multiple bacteria. The etiological agent was unknown for 26.7% of patients. The most common viruses were respiratory syncytial virus (RSV) (43.9%), rhinovirus (14.8%), parainfluenza virus (9.4%), and adenovirus (8.6%). In patients under three years of age, RSV (44.6%), rhinovirus (12.8%), and Streptococcus pneumoniae (9.9%) were the most frequent pathogens. In children aged 3e7 years, S. pneumoniae (38.9%), RSV (30.6%), Haemophilus influenzae (19.4%), and adenovirus (19.4%) were most prevalent. Finally in children over seven years, RSV (47.3%), S. pneumoniae (41.9%), and rhinovirus (21.5%) infections were most frequent. Conclusions: Viral pathogens, specifically RSV, were responsible for the majority of CAP in pediatric patients. However, both S. pneumoniae and H. influenzae contributed as major causes of disease. Commercially available multiplexing real-time PCR allowed for rapid detection of the etiological agent. Copyright © 2015, Chinese Medical Association Production. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  17. Novel Approaches to Manipulating Bacterial Pathogen Biofilms: Whole-Systems Design Philosophy and Steering Microbial Evolution.

    Science.gov (United States)

    Penn, Alexandra S

    2016-01-01

    Understanding and manipulating bacterial biofilms is crucial in medicine, ecology and agriculture and has potential applications in bioproduction, bioremediation and bioenergy. Biofilms often resist standard therapies and the need to develop new means of intervention provides an opportunity to fundamentally rethink our strategies. Conventional approaches to working with biological systems are, for the most part, "brute force", attempting to effect control in an input and effort intensive manner and are often insufficient when dealing with the inherent non-linearity and complexity of living systems. Biological systems, by their very nature, are dynamic, adaptive and resilient and require management tools that interact with dynamic processes rather than inert artefacts. I present an overview of a novel engineering philosophy which aims to exploit rather than fight those properties, and hence provide a more efficient and robust alternative. Based on a combination of evolutionary theory and whole-systems design, its essence is what I will call systems aikido; the basic principle of aikido being to interact with the momentum of an attacker and redirect it with minimal energy expenditure, using the opponent's energy rather than one's own. In more conventional terms, this translates to a philosophy of equilibrium engineering, manipulating systems' own self-organisation and evolution so that the evolutionarily or dynamically stable state corresponds to a function which we require. I illustrate these ideas with a description of a proposed manipulation of environmental conditions to alter the stability of co-operation in the context of Pseudomonas aeruginosa biofilm infection of the cystic fibrosis lung.

  18. Foreign Body Infection Models to Study Host-Pathogen Response and Antimicrobial Tolerance of Bacterial Biofilm

    Directory of Open Access Journals (Sweden)

    Justyna Nowakowska

    2014-08-01

    Full Text Available The number of implanted medical devices is steadily increasing and has become an effective intervention improving life quality, but still carries the risk of infection. These infections are mainly caused by biofilm-forming staphylococci that are difficult to treat due to the decreased susceptibility to both antibiotics and host defense mechanisms. To understand the particular pathogenesis and treatment tolerance of implant-associated infection (IAI animal models that closely resemble human disease are needed. Applications of the tissue cage and catheter abscess foreign body infection models in the mouse will be discussed herein. Both models allow the investigation of biofilm and virulence of various bacterial species and a comprehensive insight into the host response at the same time. They have also been proven to serve as very suitable tools to study the anti-adhesive and anti-infective efficacy of different biomaterial coatings. The tissue cage model can additionally be used to determine pharmacokinetics, efficacy and cytotoxicity of antimicrobial compounds as the tissue cage fluid can be aspirated repeatedly without the need to sacrifice the animal. Moreover, with the advance in innovative imaging systems in rodents, these models may offer new diagnostic measures of infection. In summary, animal foreign body infection models are important tools in the development of new antimicrobials against IAI and can help to elucidate the complex interactions between bacteria, the host immune system, and prosthetic materials.

  19. Biological Control of Bacterial Fruit Blotch of Watermelon Pathogen (Acidovorax citrulli) with Rhizosphere Associated Bacteria.

    Science.gov (United States)

    Adhikari, Mahesh; Yadav, Dil Raj; Kim, Sang Woo; Um, Young Hyun; Kim, Hyun Seung; Lee, Seong Chan; Song, Jeong Young; Kim, Hong Gi; Lee, Youn Su

    2017-04-01

    Bacterial fruit blotch (BFB), which is caused by Acidovorax citrulli, is a serious threat to watermelon growers around the world. The present study was conducted to screen effective rhizobacterial isolates against 35 different A. citrulli isolates and determine their efficacy on BFB and growth parameters of watermelon. Two rhizobacterial isolates viz. Paenibacillus polymyxa (SN-22), Sinomonas atrocyanea (NSB-27) showed high inhibitory activity in the preliminary screening and were further evaluated for their effect on BFB and growth parameters of three different watermelon varieties under greenhouse conditions. The greenhouse experiment result revealed that SN-22 and NSB-27 significantly reduced BFB and had significant stimulatory effect on total chlorophyll content, plant height, total fresh weight and total dry weight compared to uninoculated plants across the tested three watermelon varieties. Analysis of the 16S ribosomal RNA (rRNA) sequences revealed that strains SN-22 belong to P. polymyxa and NSB-27 to S. atrocyanea with the bootstrap value of 99% and 98%, respectively. The isolates SN-22 and NSB-27 were tested for antagonistic and PGP traits. The result showed that the tested isolates produced siderophore, hydrolytic enzymes (protease and cellulose), chitinase, starch hydrolytic enzymes and they showed phosphate as well as zinc solubilizing capacity. This is the first report of P. polymyxa (SN-22) and S. atrocyanea (NSB-27) as biocontrol-plant growth promoting rhizobacteria on watermelon.

  20. Biological Control of Bacterial Fruit Blotch of Watermelon Pathogen (Acidovorax citrulli) with Rhizosphere Associated Bacteria

    Science.gov (United States)

    Adhikari, Mahesh; Yadav, Dil Raj; Kim, Sang Woo; Um, Young Hyun; Kim, Hyun Seung; Lee, Seong Chan; Song, Jeong Young; Kim, Hong Gi; Lee, Youn Su

    2017-01-01

    Bacterial fruit blotch (BFB), which is caused by Acidovorax citrulli, is a serious threat to watermelon growers around the world. The present study was conducted to screen effective rhizobacterial isolates against 35 different A. citrulli isolates and determine their efficacy on BFB and growth parameters of watermelon. Two rhizobacterial isolates viz. Paenibacillus polymyxa (SN-22), Sinomonas atrocyanea (NSB-27) showed high inhibitory activity in the preliminary screening and were further evaluated for their effect on BFB and growth parameters of three different watermelon varieties under greenhouse conditions. The greenhouse experiment result revealed that SN-22 and NSB-27 significantly reduced BFB and had significant stimulatory effect on total chlorophyll content, plant height, total fresh weight and total dry weight compared to uninoculated plants across the tested three watermelon varieties. Analysis of the 16S ribosomal RNA (rRNA) sequences revealed that strains SN-22 belong to P. polymyxa and NSB-27 to S. atrocyanea with the bootstrap value of 99% and 98%, respectively. The isolates SN-22 and NSB-27 were tested for antagonistic and PGP traits. The result showed that the tested isolates produced siderophore, hydrolytic enzymes (protease and cellulose), chitinase, starch hydrolytic enzymes and they showed phosphate as well as zinc solubilizing capacity. This is the first report of P. polymyxa (SN-22) and S. atrocyanea (NSB-27) as biocontrol-plant growth promoting rhizobacteria on watermelon. PMID:28381964

  1. Host adaptation of a bacterial toxin from the human pathogen Salmonella Typhi.

    Science.gov (United States)

    Deng, Lingquan; Song, Jeongmin; Gao, Xiang; Wang, Jiawei; Yu, Hai; Chen, Xi; Varki, Nissi; Naito-Matsui, Yuko; Galán, Jorge E; Varki, Ajit

    2014-12-04

    Salmonella Typhi is an exclusive human pathogen that causes typhoid fever. Typhoid toxin is a S. Typhi virulence factor that can reproduce most of the typhoid fever symptoms in experimental animals. Toxicity depends on toxin binding to terminally sialylated glycans on surface glycoproteins. Human glycans are unusual because of the lack of CMAH, which in other mammals converts N-acetylneuraminic acid (Neu5Ac) to N-glycolylneuraminic acid (Neu5Gc). Here, we report that typhoid toxin binds to and is toxic toward cells expressing glycans terminated in Neu5Ac (expressed by humans) over glycans terminated in Neu5Gc (expressed by other mammals). Mice constitutively expressing CMAH thus displaying Neu5Gc in all tissues are resistant to typhoid toxin. The atomic structure of typhoid toxin bound to Neu5Ac reveals the structural bases for its binding specificity. These findings provide insight into the molecular bases for Salmonella Typhi's host specificity and may help the development of therapies for typhoid fever.

  2. Laboratory monitoring of bacterial gastroenteric pathogens Salmonella and Shigella in Shanghai, China 2006-2012.

    Science.gov (United States)

    Zhang, J; Wang, F; Jin, H; Hu, J; Yuan, Z; Shi, W; Yang, X; Meng, J; Xu, X

    2015-02-01

    In 2006 we initiated an enhanced laboratory-based surveillance of Salmonella and Shigella infections in Shanghai, China. A total of 4483 Salmonella and 2226 Shigella isolates were recovered from stool specimens by 2012. In 80 identified Salmonella serovars, Enteritidis (34·5%) and Typhimurium (26·2%) were the most common. Shigella (S.) sonnei accounted for 63·9% of human Shigella infections over the same time period, and replaced S. flexneri to become the primary cause of shigellosis since 2010. Overall, a high level of antimicrobial resistance was observed in Salmonella and Shigella, particularly to nalidixic acid, ampicillin, and tetracycline. Ciprofloxacin resistance was common in Salmonella Typhimurium (21·0%) and S. flexneri (37·6%). The cephalosporin resistance in both pathogens also increased over the years, ranging from 3·4% to 7·0% in Salmonella, and from 10·4% to 28·6% in Shigella. Resistance to multiple antimicrobials was also identified in a large number of the isolates. This study provides insight into the distribution of Salmonella and Shigella in diarrhoeal diseases.

  3. Antibiotic resistance in bacterial pathogens from retail raw meats and food-producing animals in Japan.

    Science.gov (United States)

    Hiroi, Midori; Kawamori, Fumihiko; Harada, Tetsuya; Sano, Yono; Miwa, Norinaga; Sugiyama, Kanji; Hara-Kudo, Yukiko; Masuda, Takashi

    2012-10-01

    To determine the prevalence and antimicrobial susceptibility profiles of Campylobacter, Salmonella, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and vancomycin-resistant enterococci (VRE) in food-producing animals and retail raw meats in Japan, raw meat samples as well as food-producing animal feces, cutaneous swabs, and nasal swabs collected from 2004 to 2006 were analyzed. Isolation rates of Campylobacter jejuni and Campylobacter coli, Salmonella, and S. aureus were 34.6% (363 of 1,050), 2.7% (28 of 1,050), and 32.8% (238 of 725), respectively. MRSA was isolated from 3% (9 of 300) of meat samples. No VRE were isolated in this study. Antibiotic resistance in C. coli was higher than that in C. jejuni. Three C. jejuni isolates from a patient with diarrhea in a hospital of Shizuoka Prefecture and two chicken samples that exhibited resistance to ciprofloxacin had identical pulsed-field gel electrophoresis patterns, suggesting that ciprofloxacin-resistant C. jejuni could have been distributed in meat. S. aureus isolates showed the highest level of resistance to ampicillin and tetracycline. Resistance to tetracycline in S. aureus isolates from beef was lower than that seen in isolates from chicken and pork (P food-producing animals and retail domestic meats in Japan, although Campylobacter isolates resistant to fluoroquinolone and erythromycin were detected. The occurrence of antimicrobial-resistant pathogens should be monitored continuously to improve the management of the risks associated with antimicrobial drug resistance transferred from food-producing animals to humans.

  4. Real-Time PCR Methods for Detection of Foodborne Bacterial Pathogens in Meat and Meat Products

    Science.gov (United States)

    Hernández, Marta; Hansen, Flemming; Cook, Nigel; Rodríguez-Lázaro, David

    As a consequence of the potential hazards posed by the presence of microbial pathogens, microbiological quality control programmes are being increasingly applied throughout the meat production chain in order to minimize the risk of infection for the consumer. Classical microbiological methods to detect the presence of microorganisms, involving enrichment and isolation of presumptive colonies of bacteria on solid media, and final confirmation by biochemical and/or serological identification, although remaining the approach of choice in routine analytical laboratories, can be laborious and time consuming. The adoption of molecular techniques in microbial diagnostics has become a promising alternative approach, as they possess inherent advantages such as shorter time to results, excellent detection limits, specificity and potential for automation. Several molecular detection techniques have been devised in the last two decades, such as nucleic acid sequence-based amplification (NASBA) (Cook, 2003; Rodriguez-Lazaro, Hernandez, D’Agostino, & Cook, 2006) and loop-mediated isothermal amplification (Notomi et al., 2000), but the one which has undergone the most extensive development as a practical food analytical tool is the polymerase chain reaction (PCR) (Hoorfar & Cook, 2003; Malorny, Tassios, et al., 2003).

  5. Redox cycling amplified electrochemical detection of DNA hybridization: application to pathogen E. coli bacterial RNA.

    Science.gov (United States)

    Walter, Anne; Wu, Jie; Flechsig, Gerd-Uwe; Haake, David A; Wang, Joseph

    2011-03-09

    An electrochemical genosensor in which signal amplification is achieved using p-aminophenol (p-AP) redox cycling by nicotinamide adenine dinucleotide (NADH) is presented. An immobilized thiolated capture probe is combined with a sandwich-type hybridization assay, using biotin as a tracer in the detection probe, and streptavidin-alkaline phosphatase as reporter enzyme. The phosphatase liberates the electrochemical mediator p-AP from its electrically inactive phosphate derivative. This generated p-AP is electrooxidized at an Au electrode modified self-assembled monolayer to p-quinone imine (p-QI). In the presence of NADH, p-QI is reduced back to p-AP, which can be re-oxidized on the electrode and produce amplified signal. A detection limit of 1 pM DNA target is offered by this simple one-electrode, one-enzyme format redox cycling strategy. The redox cycling design is applied successfully to the monitoring of the 16S rRNA of E. coli pathogenic bacteria, and provides a detection limit of 250 CFU μL(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Multigenic natural variation underlies Caenorhabditis elegans olfactory preference for the bacterial pathogen Serratia marcescens.

    Science.gov (United States)

    Glater, Elizabeth E; Rockman, Matthew V; Bargmann, Cornelia I

    2014-02-19

    The nematode Caenorhabditis elegans can use olfaction to discriminate among different kinds of bacteria, its major food source. We asked how natural genetic variation contributes to choice behavior, focusing on differences in olfactory preference behavior between two wild-type C. elegans strains. The laboratory strain N2 strongly prefers the odor of Serratia marcescens, a soil bacterium that is pathogenic to C. elegans, to the odor of Escherichia coli, a commonly used laboratory food source. The divergent Hawaiian strain CB4856 has a weaker attraction to Serratia than the N2 strain, and this behavioral difference has a complex genetic basis. At least three quantitative trait loci (QTLs) from the CB4856 Hawaii strain (HW) with large effect sizes lead to reduced Serratia preference when introgressed into an N2 genetic background. These loci interact and have epistatic interactions with at least two antagonistic QTLs from HW that increase Serratia preference. The complex genetic architecture of this C. elegans trait is reminiscent of the architecture of mammalian metabolic and behavioral traits.

  7. Biological and genetic factors regulating natural competence in a bacterial plant pathogen.

    Science.gov (United States)

    Kung, Stephanie H; Almeida, Rodrigo P P

    2014-01-01

    For naturally competent bacteria, spatially structured growth can provide an environment for enhanced horizontal gene transfer through transformation and recombination. DNA is often present in the extracellular environment, such as in the extracellular matrix of biofilms, and the lysis of a single cell can result in high local DNA concentrations. Xylella fastidiosa is a naturally competent plant pathogen that typically lives in a surface-attached state, yet previous work characterizing the competence of this organism was conducted with planktonic cells in liquid environments. Here, we show that transformation and recombination efficiencies are two to three orders of magnitude higher for cells grown on solid compared with liquid media, with maximum recombination efficiencies of about 10(-3). Cells were highly competent throughout their exponential growth phase, with no significant change in recombination efficiencies until population growth rates began to slow. Mutations in type IV pili, competency-related, and cell-cell signalling genes significantly impacted the ability of X. fastidiosa to acquire and incorporate DNA. Because X. fastidiosa is highly competent when growing in a surface-attached state, as it does within its insect vectors and host plants, recombination of naturally transformed DNA could be a significant route by which horizontal gene transfer occurs in natural environments.

  8. Label-free molecular imaging of bacterial communities of the opportunistic pathogen Pseudomonas aeruginosa