WorldWideScience

Sample records for mammalian pathogenic bacteria

  1. 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

  2. Mucosal immunity to pathogenic intestinal bacteria.

    Science.gov (United States)

    Perez-Lopez, Araceli; Behnsen, Judith; Nuccio, Sean-Paul; Raffatellu, Manuela

    2016-03-01

    The intestinal mucosa is a particularly dynamic environment in which the host constantly interacts with trillions of commensal microorganisms, known as the microbiota, and periodically interacts with pathogens of diverse nature. In this Review, we discuss how mucosal immunity is controlled in response to enteric bacterial pathogens, with a focus on the species that cause morbidity and mortality in humans. We explain how the microbiota can shape the immune response to pathogenic bacteria, and we detail innate and adaptive immune mechanisms that drive protective immunity against these pathogens. The vast diversity of the microbiota, pathogens and immune responses encountered in the intestines precludes discussion of all of the relevant players in this Review. Instead, we aim to provide a representative overview of how the intestinal immune system responds to pathogenic bacteria.

  3. Microgravity effects on pathogenicity of bacteria

    Directory of Open Access Journals (Sweden)

    Ya-juan WANG

    2013-01-01

    Full Text Available Microgravity is one of the important environmental conditions during spaceflight. A series of studies have shown that many kinds of bacteria could be detected in space station and space shuttle. Space environment or simulated microgravity may throw a certain influence on those opportunistic pathogens and lead to some changes on their virulence, biofilm formation and drug tolerance. The mechanism of bacteria response to space environment or simulated microgravity has not been defined. However, the conserved RNA-binding protein Hfq has been identified as a likely global regulator involved in the bacteria response to this environment. In addition, microgravity effects on bacterial pathogenicity may threaten astronauts' health. The present paper will focus on microgravity-induced alterations of pathogenicity and relative mechanism in various opportunistic pathogens.

  4. Threats and opportunities of plant pathogenic bacteria.

    Science.gov (United States)

    Tarkowski, Petr; Vereecke, Danny

    2014-01-01

    Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Nyctanthes arbortristis Against Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Savita G. Aggarwal

    2013-09-01

    Full Text Available Nature has provided a complete storehouse of knowledge of drug. Herbal drugs constitute a major part in all traditional systems of medicines. Since ancient times mankind has exploited nature for all kind of useful production and enjoyed the colors, flavors and fragrances of flowers, food etc. Rigveda, the book supplies curious information on this subject. Despite the importance of western medicines, towards the end of the 20th century there again began a revival of interest in traditional medicines not only in developing countries, but also in the developed countries. The resurgence of plant based medicine is mainly due to the increasing evidences of the health hazards associated with the indiscriminate use of the modern medicine such as antibiotic, steroids and other synthetic drug. The plants used in the traditional system of medicine of India and china are now receiving much scientific attention. With the continuous use of antibiotics, microorganisms have become resistant. So, it is necessary to evaluate, in a scientific base, the potential use of folk medicine for the treatment of infectious disease produced by common pathogens. Thus it was thought worthwhile to carry out the systematic chemical examination of Nyctanthes arbortristis. Studies had been conducted to evaluate the antimicrobial properties of leaves of Nyctanthes arbortristis. It belongs to the family verbenaceae. The plant material was collected from herbal local nursery, and was stored for further studies. The different solvent extracts were prepared on the basis of polarity. Phytochemical analytical tests were carried out for preliminary investigation. Antimicrobial activities were evaluated using pathogenic microbes. The different solvent extracts of test material showed marked antimicrobial activity against pathogenic microorganism. The results showed that the test plant material was susceptible to different microorganism.

  6. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology...

  7. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology...

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

    Science.gov (United States)

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

    2016-03-01

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

  9. Bioactive proteins against pathogenic and spoilage bacteria

    Directory of Open Access Journals (Sweden)

    Mahmoud Z. Sitohy

    2014-10-01

    Full Text Available Background: It is likely that both human nutrition and the nutrition of livestock are benefited by the presence of bioactive proteins within their respective diet regimes. Bioactive proteins have been defined as specific protein fragments that positively impact bodily functions or conditions and may, ultimately, influence overall human health. The ingestion of bioactive proteins may have an effect on the major body systems—namely, the cardiovascular, digestive, immune and nervous systems. According to their functional properties, bioactive proteins may be classified as antimicrobial, antithrombotic, antihypertensive, opioid, immune-modulatory, mineral binding and anti-oxidative. There are many examples of biologically active food proteins and active peptides that can be obtained from various food protein sources. They have a physiological significance beyond the pure nutritional requirements; in other wordsthey have the acquisition of nitrogen for normal growth and maintenance. Objective: This study aims to specify and characterize the extent and mode of action of bioactive proteins in their native form, (glycinin, glycinin basic sub-unit and β-conglycinin against specific main pathogens (Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica serovar Enteritidis. We will be using standard media while identifying the main constituents responsible for this action. Methods: Glycinin, basic sub-unit and β-conglycinin were isolated from soybean protein and tested for their antimicrobial action against pathogenic and spoilage bacteria, They were thencompared to the properties of penicillin. Methylated soybean protein and also methylated chickpea protein (MSP and MCP, with isoelectric points around pI 8, were prepared by esterifying. 83 % of their free carboxyl groups and their interactions with Gram positive and Gram negative bacteria were examined. Results: The three divisions of cationic proteins exhibited antibacterial

  10. Laser-Based Identification of Pathogenic Bacteria

    Science.gov (United States)

    Rehse, Steven J.

    2009-01-01

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

  11. Laser-Based Identification of Pathogenic Bacteria

    Science.gov (United States)

    Rehse, Steven J.

    2009-01-01

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

  12. Electrical detection of pathogenic bacteria via immobilized antimicrobial peptides

    National Research Council Canada - National Science Library

    Manu S. Mannoor; Siyan Zhang; A. James Link; Michael C. McAlpine; Charles Lieber

    2010-01-01

    The development of a robust and portable biosensor for the detection of pathogenic bacteria could impact areas ranging from waterquality monitoring to testing of pharmaceutical products for bacterial contamination...

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

    Science.gov (United States)

    Bäumler, Andreas J; Sperandio, Vanessa

    2016-07-07

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

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

    Directory of Open Access Journals (Sweden)

    Alix M Denoncourt

    2014-05-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  16. Deoxyribonucleoside kinases activate nucleoside antibiotics in severely pathogenic bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Shannon, O.; Clausen, A.R.;

    2007-01-01

    Common bacterial pathogens are becoming progressively more resistant to traditional antibiotics, representing a major public-health crisis. Therefore, there is a need for a variety of antibiotics with alternative modes of action. In our study, several nucleoside analogs were tested against...... alternative for combating pathogenic bacteria....

  17. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria

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    Larissa D Cunha

    2013-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Rotariu, Ovidiu [School of Biological Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen (United Kingdom); Ogden, Iain D [Department of Medical Microbiology, University of Aberdeen, Aberdeen (United Kingdom); MacRae, Marion [Department of Medical Microbiology, University of Aberdeen, Aberdeen (United Kingdom); Udrea, Laura Elena [National Institute of R-D for Technical Physics I.F.T. Iasi, Mangeron 47 Blvd., Iasi (Romania); Strachan, Norval J C [School of Biological Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen (United Kingdom)

    2005-06-21

    The standard method of immunomagnetic separation for isolating pathogenic bacteria from food and environmental matrices processes 1 ml volumes. Pathogens present at low levels (<0.5 pathogenic bacteria/g) will not be consistently detected by this method. Here a multiple sample flow through immunomagnetic separator has been designed and tested to process large volume samples (50 to 250 ml). Preliminary results show >97% recovery of polydisperse magnetic particles (diameter range 1 to 8 {mu}m) containing 29-33% w/w Fe{sub 3}O{sub 4} content. Between 70 and 130 times more of the pathogenic bacteria Escherichia coli O157 is recovered from PBS compared with the standard 1 ml method. Also, the recovery of E. coli O157 from beef mince homogenates, after a 4 h incubation at 42 deg. C, is between 80 and 180 times higher than the standard 1 ml method.

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Detection of pathogenic gram negative bacteria using infrared thermography

    Science.gov (United States)

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

    2012-11-01

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

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

    Science.gov (United States)

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

    2006-01-01

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

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

    Science.gov (United States)

    Jing, Ming; Wang, Lei

    2016-02-15

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

  3. Insights into Cross-Kingdom Plant Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Morgan W.B. Kirzinger

    2011-11-01

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

  4. Bacteriocins active against plant pathogenic bacteria.

    Science.gov (United States)

    Grinter, Rhys; Milner, Joel; Walker, Daniel

    2012-12-01

    Gram-negative phytopathogens cause significant losses in a diverse range of economically important crop plants. The effectiveness of traditional countermeasures, such as the breeding and introduction of resistant cultivars, is often limited by the dearth of available sources of genetic resistance. An alternative strategy to reduce loss to specific bacterial phytopathogens is to use narrow-spectrum protein antibiotics such as colicin-like bacteriocins as biocontrol agents. A number of colicin-like bacteriocins active against phytopathogenic bacteria have been described previously as have strategies for their application to biocontrol. In the present paper, we discuss these strategies and our own recent work on the identification and characterization of candidate bacteriocins and how these potent and selective antimicrobial agents can be effectively applied to the control of economically important plant disease.

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

    DEFF Research Database (Denmark)

    Ibfelt, Tobias; Engelund, Eva Høy; Permin, Anders;

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

  7. Bactericidal Effect of Gold-Chitosan Nanocomposites in Coculture Models of Pathogenic Bacteria and Human Macrophages.

    Science.gov (United States)

    Mendoza, Gracia; Regiel-Futyra, Anna; Andreu, Vanesa; Sebastián, Víctor; Kyzioł, Agnieszka; Stochel, Grażyna; Arruebo, Manuel

    2017-05-31

    The ability of pathogenic bacteria to develop resistance mechanisms to avoid the antimicrobial potential of antibiotics has become an increasing problem for the healthcare system. The search for more effective and selective antimicrobial materials, though not harmful to mammalian cells, seems imperative. Herein we propose the use of gold-chitosan nanocomposites as effective bactericidal materials avoiding damage to human cells. Nanocomposites were obtained by taking advantage of the reductive and stabilizing action of chitosan solutions on two different gold precursor concentrations. The resulting nanocomposites were added at different final concentrations to a coculture model formed by Gram-positive (Staphylococcus aureus) or Gram-negative (Escherichia coli) bacteria and human macrophages. Gold-chitosan colloids exhibited superior bactericidal ability against both bacterial models without showing cytotoxicity on human cells at the concentrations tested. Morphological and in vitro viability studies supported the feasibility of the infection model here described to test novel bactericidal nanomaterials. Flow cytometry and scanning electron microscopy analyses pointed to the disruption of the bacterial wall as the lethal mechanism. Data obtained in the present study suggest that gold-chitosan nanocomposites are powerful and promising nanomaterials for reducing bacteria-associated infections, respecting the integrity of mammalian cells, and displaying high selectivity against the studied bacteria.

  8. Natural occurrence and pathogenicity of Xanthomonas bacteria on ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    The bacterial genus Xanthomonas consists of several species of economic importance, among which. Xanthomonas ... of economic importance as they affect the production of different crops ..... significantly greater than for the others. As a result, ..... NW (ed) Laboratory guide for identification of plant pathogenic bacteria, 2nd ...

  9. Molecular battles between plant and pathogenic bacteria in the phyllosphere

    Directory of Open Access Journals (Sweden)

    C.M. Baker

    2010-08-01

    Full Text Available The phyllosphere, i.e., the aerial parts of the plant, provides one of the most important niches for microbial colonization. This niche supports the survival and, often, proliferation of microbes such as fungi and bacteria with diverse lifestyles including epiphytes, saprophytes, and pathogens. Although most microbes may complete the life cycle on the leaf surface, pathogens must enter the leaf and multiply aggressively in the leaf interior. Natural surface openings, such as stomata, are important entry sites for bacteria. Stomata are known for their vital role in water transpiration and gas exchange between the plant and the environment that is essential for plant growth. Recent studies have shown that stomata can also play an active role in limiting bacterial invasion of both human and plant pathogenic bacteria as part of the plant innate immune system. As counter-defense, plant pathogens such as Pseudomonas syringae pv tomato (Pst DC3000 use the virulence factor coronatine to suppress stomate-based defense. A novel and crucial early battleground in host-pathogen interaction in the phyllosphere has been discovered with broad implications in the study of bacterial pathogenesis, host immunity, and molecular ecology of bacterial diseases.

  10. Human pathogenic bacteria, fungi, and viruses in Drosophila: disease modeling, lessons, and shortcomings.

    Science.gov (United States)

    Panayidou, Stavria; Ioannidou, Eleni; Apidianakis, Yiorgos

    2014-02-15

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

  11. Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper.

    Science.gov (United States)

    Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

    2012-07-01

    Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks.

  12. Antibacterial effect of Gracilaria verrucosa bioactive on fish pathogenic bacteria

    OpenAIRE

    Maftuch,; Isma Kurniawati; Awaludin Adam; I’ah Zamzami

    2016-01-01

    Gracilaria verrucosa seaweed is a type of seaweed commonly found in water. This study was conducted to investigate the effect of G. verrucosa on fish pathogenic bacteria to support fish farming. The method used in this research was the separation of G. verrucosa fractions using column chromatography. The active antibacterial fraction of G. verrucosa which is obtained from column chromatography indicated fractions containing antibacterial compounds. It was fraction number 3 by using an eluent ...

  13. Antibacterial activity of caffeine against plant pathogenic bacteria.

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

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

  15. Insect symbiotic bacteria harbour viral pathogens for transovarial transmission.

    Science.gov (United States)

    Jia, Dongsheng; Mao, Qianzhuo; Chen, Yong; Liu, Yuyan; Chen, Qian; Wu, Wei; Zhang, Xiaofeng; Chen, Hongyan; Li, Yi; Wei, Taiyun

    2017-03-06

    Many insects, including mosquitoes, planthoppers, aphids and leafhoppers, are the hosts of bacterial symbionts and the vectors for transmitting viral pathogens(1-3). In general, symbiotic bacteria can indirectly affect viral transmission by enhancing immunity and resistance to viruses in insects(3-5). Whether symbiotic bacteria can directly interact with the virus and mediate its transmission has been unknown. Here, we show that an insect symbiotic bacterium directly harbours a viral pathogen and mediates its transovarial transmission to offspring. We observe rice dwarf virus (a plant reovirus) binding to the envelopes of the bacterium Sulcia, a common obligate symbiont of leafhoppers(6-8), allowing the virus to exploit the ancient oocyte entry path of Sulcia in rice leafhopper vectors. Such virus-bacterium binding is mediated by the specific interaction of the viral capsid protein and the Sulcia outer membrane protein. Treatment with antibiotics or antibodies against Sulcia outer membrane protein interferes with this interaction and strongly prevents viral transmission to insect offspring. This newly discovered virus-bacterium interaction represents the first evidence that a viral pathogen can directly exploit a symbiotic bacterium for its transmission. We believe that such a model of virus-bacterium communication is a common phenomenon in nature.

  16. Living biointerfaces based on non-pathogenic bacteria support stem cell differentiation

    Science.gov (United States)

    Hay, Jake J.; Rodrigo-Navarro, Aleixandre; Hassi, Karoliina; Moulisova, Vladimira; Dalby, Matthew J.; Salmeron-Sanchez, Manuel

    2016-02-01

    Lactococcus lactis, a non-pathogenic bacteria, has been genetically engineered to express the III7–10 fragment of human fibronectin as a membrane protein. The engineered L. lactis is able to develop biofilms on different surfaces (such as glass and synthetic polymers) and serves as a long-term substrate for mammalian cell culture, specifically human mesenchymal stem cells (hMSC). This system constitutes a living interface between biomaterials and stem cells. The engineered biofilms remain stable and viable for up to 28 days while the expressed fibronectin fragment induces hMSC adhesion. We have optimised conditions to allow long-term mammalian cell culture, and found that the biofilm is functionally equivalent to a fibronectin-coated surface in terms of osteoblastic differentiation using bone morphogenetic protein 2 (BMP-2) added to the medium. This living bacteria interface holds promise as a dynamic substrate for stem cell differentiation that can be further engineered to express other biochemical cues to control hMSC differentiation.

  17. Antibacterial effect of Gracilaria verrucosa bioactive on fish pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Maftuch

    2016-12-01

    Full Text Available Gracilaria verrucosa seaweed is a type of seaweed commonly found in water. This study was conducted to investigate the effect of G. verrucosa on fish pathogenic bacteria to support fish farming. The method used in this research was the separation of G. verrucosa fractions using column chromatography. The active antibacterial fraction of G. verrucosa which is obtained from column chromatography indicated fractions containing antibacterial compounds. It was fraction number 3 by using an eluent 16 (ethanol: 4 (ethyl acetate. Furthermore, based on phytochemical screening, ultraviolet spectrophotometer and LC–MS analysis, antibacterial compounds contained in those fraction number 3 are Alkaloid, Flavonoid, Tannin, Phenolic compound. Based on LC–MS and UV–Vis analysis, flavonoid group, Quercetin-7-methyl-ether is a dominant group of the antibacterial compound on fraction no. 3. This fraction had moderate antibacterial activity against Aeromonas hydrophila, Pseudomonas aeruginosa, Pseudomonas putida and had weak antibacterial activity against Vibrio harveyi and Vibrio algynoliticus bacteria.

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

    Science.gov (United States)

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

    2013-07-01

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

  19. Endobiotic bacteria and their pathogenic potential in cnidarian tentacles

    Science.gov (United States)

    Schuett, Christian; Doepke, Hilke

    2010-09-01

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

  20. Innovative tools for detection of plant pathogenic viruses and bacteria.

    Science.gov (United States)

    López, María M; Bertolini, Edson; Olmos, Antonio; Caruso, Paola; Gorris, María Teresa; Llop, Pablo; Penyalver, Ramón; Cambra, Mariano

    2003-12-01

    Detection of harmful viruses and bacteria in plant material, vectors or natural reservoirs is essential to ensure safe and sustainable agriculture. The techniques available have evolved significantly in the last few years to achieve rapid and reliable detection of pathogens, extraction of the target from the sample being important for optimising detection. For viruses, sample preparation has been simplified by imprinting or squashing plant material or insect vectors onto membranes. To improve the sensitivity of techniques for bacterial detection, a prior enrichment step in liquid or solid medium is advised. Serological and molecular techniques are currently the most appropriate when high numbers of samples need to be analysed. Specific monoclonal and/or recombinant antibodies are available for many plant pathogens and have contributed to the specificity of serological detection. Molecular detection can be optimised through the automatic purification of nucleic acids from pathogens by columns or robotics. New variants of PCR, such as simple or multiplex nested PCR in a single closed tube, co-operative-PCR and real-time monitoring of amplicons or quantitative PCR, allow high sensitivity in the detection of one or several pathogens in a single assay. The latest development in the analysis of nucleic acids is micro-array technology, but it requires generic DNA/RNA extraction and pre-amplification methods to increase detection sensitivity. The advances in research that will result from the sequencing of many plant pathogen genomes, especially now in the era of proteomics, represent a new source of information for the future development of sensitive and specific detection techniques for these microorganisms.

  1. The antimicrobial spectra of selected Penicillia against some pathogenic bacteria and yeasts

    Directory of Open Access Journals (Sweden)

    Shashi Chauhan

    2014-08-01

    Full Text Available The antagonista activity of eight isolaies of penicillia bas been studied against 13 pathogenic organisms, which included 6 Gram-positive bacteria, 4 Gram-negative bacteria and 3 yeasts.

  2. Nanoformulated antibiotics: the next step for pathogenic bacteria control.

    Science.gov (United States)

    Saúde, Amanda Caroline Marques; Cherobim, Mariana Dornelles; Amaral, André Corrêa; Dias, Simoní Campos; Franco, Octávio Luiz

    2013-01-01

    The resistance of infectious bacteria to current antibiotics is a worldwide problem. Previous studies have demonstrated the efficacy of nanostructured molecules against pathogens as an innovative methodology for the development of novel drugs. Currently, 95% of properties limited pharmacies applicability such as low solubility, short half-life in the circulatory system, toxicity associated to controlled release and immunogenicity. Furthermore, nanobiotechnology provides a different perspective for modifying these properties and allows innovative drug development. In this context, this review aims to describe different methods, polymers, and drugs used to obtain and analyze nanostructures associated with antibiotics as an unconventional and innovative tool for bacterial control. Biotechnology provides a different perspective for modifying drug properties and allows innovative drug development. This review describes nanostructures in association with antibiotics as an unconventional and innovative tool for bacterial control.

  3. Evolutionary aspects of collective motility in pathogenic bacteria

    Science.gov (United States)

    Deforet, Maxime; Xavier, Joao

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

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

    Directory of Open Access Journals (Sweden)

    Fontes Belchor

    2012-12-01

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

  5. Dual Targeting of Intracellular Pathogenic Bacteria with a Cleavable Conjugate of Kanamycin and an Antibacterial Cell-Penetrating Peptide.

    Science.gov (United States)

    Brezden, Anna; Mohamed, Mohamed F; Nepal, Manish; Harwood, John S; Kuriakose, Jerrin; Seleem, Mohamed N; Chmielewski, Jean

    2016-08-31

    Bacterial infection caused by intracellular pathogens, such as Mycobacterium, Salmonella, and Brucella, is a burgeoning global health epidemic that necessitates urgent action. However, the therapeutic value of a number of antibiotics, including aminoglycosides, against intracellular pathogenic bacteria is compromised due to their inability to traverse eukaryotic membranes. For this significant problem to be addressed, a cleavable conjugate of the antibiotic kanamycin and a nonmembrane lytic, broad-spectrum antimicrobial peptide with efficient mammalian cell penetration, P14LRR, was prepared. This approach allows kanamycin to enter mammalian cells as a conjugate linked via a tether that breaks down in the reducing environment within cells. Potent antimicrobial activity of the P14KanS conjugate was demonstrated in vitro, and this reducible conjugate effectively cleared intracellular pathogenic bacteria within macrophages more potently than that of a conjugate lacking the disulfide moiety. Notably, successful clearance of Mycobacterium tuberculosis within macrophages was observed with the dual antibiotic conjugate, and Salmonella levels were significantly reduced in an in vivo Caenorhabditis elegans model.

  6. The avian and mammalian host range of highly pathogenic avian H5N1 influenza.

    Science.gov (United States)

    Kaplan, Bryan S; Webby, Richard J

    2013-12-05

    Highly pathogenic H5N1 influenza viruses have been isolated from a number of avian and mammalian species. Despite intensive control measures the number of human and animal cases continues to increase. A more complete understanding of susceptible species and of contributing environmental and molecular factors is crucial if we are to slow the rate of new cases. H5N1 is currently endemic in domestic poultry in only a handful of countries with sporadic and unpredictable spread to other countries. Close contact of terrestrial bird or mammalian species with infected poultry/waterfowl or their biological products is the major route for interspecies transmission. Intra-species transmission of H5N1 in mammals, including humans, has taken place on a limited scale though it remains to be seen if this will change; recent laboratory studies suggest that it is indeed possible. Here we review the avian and mammalian species that are naturally susceptible to H5N1 infection and the molecular factors associated with its expanded host range.

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

    DEFF Research Database (Denmark)

    Bruhn, Jesper Bartholin; Dalsgaard, Inger; Nielsen, K.F.

    2005-01-01

    and plant-pathogenic bacteria. A total of 59 strains, representing 9 different fish pathogenic species, were tested against 2 AHL monitor bacteria (Agrobacterium tumefaciens NT1 [pZLR4] and Chromobacterium violaceum CV026) in a well diffusion assay and by thin-layer chromatography (TLC). Representative...

  8. Effects of Ethanolic Ferolagu angulata Extract on Pathogenic Gastrointestinal Bacteria and Probiotic Bacteria in Skimmed Milk Medium

    Directory of Open Access Journals (Sweden)

    Reza Naghiha

    2016-12-01

    Full Text Available Background:    Due to excessive consumption of synthetic drugs, drug resistance rate of pathogenic bacteria is increasing and there is an ever-increasing need to find new safe compounds to tackle this problem. This study was conducted to investigate the consequences of chavill extract on the growth and viability of gastrointestinal pathogenic bacterium and probiotics bacteria. Methods:    The experiment contained three levels of the chavill extract concentrations (0, 1 and 3% which were added to the milk free fat in accompany with three probiotic bacteria (Lactobacillus acidophilus, Lactobacillus casei and lactobacillus plantaram and a pathogenic gastrointestinal bacterium (Salmonella typhimurium. Bacterial inoculums (1×107 CFU/ml with different concentrations of chavill extract were added to skimmed milk medium and bacteria growth were enumerated. Results:  The concentration of 1% chavill extract significantly increased the total count of probiotic bacteria compared to the control group, while the number of pathogenic bacteria was decreased. At 3% chavill extract the growth of Lactobacillus acidophilus and Lactobacillus plantaram were increased. On the other hand, it prevented the growth of Salmonella typhimurium Conclusion:   Chavill extracts would play as an alternative to antibiotics in pharmacological studies to decreases harmful bacteria and increase probiotic bacteria.

  9. Pathogenic Leptospires Modulate Protein Expression and Post-translational Modifications in Response to Mammalian Host Signals

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    Jarlath E. Nally

    2017-08-01

    Full Text Available Pathogenic species of Leptospira cause leptospirosis, a bacterial zoonotic disease with a global distribution affecting over one million people annually. Reservoir hosts of leptospirosis, including rodents, dogs, and cattle, exhibit little to no signs of disease but shed large numbers of organisms in their urine. Transmission occurs when mucosal surfaces or abraded skin come into contact with infected urine or urine-contaminated water or soil. Whilst little is known about how Leptospira adapt to and persist within a reservoir host, in vitro studies suggest that leptospires alter their transcriptomic and proteomic profiles in response to environmental signals encountered during mammalian infection. We applied the dialysis membrane chamber (DMC peritoneal implant model to compare the whole cell proteome of in vivo derived leptospires with that of leptospires cultivated in vitro at 30°C and 37°C by 2-dimensional difference in-gel electrophoresis (2-D DIGE. Of 1,735 protein spots aligned across 9 2-D DIGE gels, 202 protein spots were differentially expressed (p < 0.05, fold change >1.25 or < −1.25 across all three conditions. Differentially expressed proteins were excised for identification by mass spectrometry. Data are available via ProteomeXchange with identifier PXD006995. The greatest differences were detected when DMC-cultivated leptospires were compared with IV30- or IV37-cultivated leptospires, including the increased expression of multiple isoforms of Loa22, a known virulence factor. Unexpectedly, 20 protein isoforms of LipL32 and 7 isoforms of LipL41 were uniformly identified by DIGE as differentially expressed, suggesting that unique post-translational modifications (PTMs are operative in response to mammalian host conditions. To test this hypothesis, a rat model of persistent renal colonization was used to isolate leptospires directly from the urine of experimentally infected rats. Comparison of urinary derived leptospires to IV30

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

    Science.gov (United States)

    Wallmann, Jürgen

    2006-06-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

  12. In Vitro Studies of Chromone-Tetrazoles against Pathogenic Protozoa, Bacteria, and Fungi

    Directory of Open Access Journals (Sweden)

    Pedro A. Cano

    2015-07-01

    Full Text Available In vitro studies to fourteen previously synthesized chromone-tetrazoles and four novel fluorine-containing analogs were conducted against pathogenic protozoan (Entamoeba histolytica, pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus, and human fungal pathogens (Sporothrix schenckii, Candida albicans, and Candida tropicalis, which have become in a serious health problem, mainly in tropical countries.

  13. In Vitro Studies of Chromone-Tetrazoles against Pathogenic Protozoa, Bacteria, and Fungi.

    Science.gov (United States)

    Cano, Pedro A; Islas-Jácome, Alejandro; Rangel-Serrano, Ángeles; Anaya-Velázquez, Fernando; Padilla-Vaca, Felipe; Trujillo-Esquivel, Elías; Ponce-Noyola, Patricia; Martínez-Richa, Antonio; Gámez-Montaño, Rocío

    2015-07-08

    In vitro studies to fourteen previously synthesized chromone-tetrazoles and four novel fluorine-containing analogs were conducted against pathogenic protozoan (Entamoeba histolytica), pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus), and human fungal pathogens (Sporothrix schenckii, Candida albicans, and Candida tropicalis), which have become in a serious health problem, mainly in tropical countries.

  14. Fungal Mimicry of a Mammalian Aminopeptidase Disables Innate Immunity and Promotes Pathogenicity.

    Science.gov (United States)

    Sterkel, Alana K; Lorenzini, Jenna L; Fites, J Scott; Subramanian Vignesh, Kavitha; Sullivan, Thomas D; Wuthrich, Marcel; Brandhorst, Tristan; Hernandez-Santos, Nydiaris; Deepe, George S; Klein, Bruce S

    2016-03-09

    Systemic fungal infections trigger marked immune-regulatory disturbances, but the mechanisms are poorly understood. We report that the pathogenic yeast of Blastomyces dermatitidis elaborates dipeptidyl-peptidase IVA (DppIVA), a close mimic of the mammalian ectopeptidase CD26, which modulates critical aspects of hematopoiesis. We show that, like the mammalian enzyme, fungal DppIVA cleaved C-C chemokines and GM-CSF. Yeast producing DppIVA crippled the recruitment and differentiation of monocytes and prevented phagocyte activation and ROS production. Silencing fungal DppIVA gene expression curtailed virulence and restored recruitment of CCR2(+) monocytes, generation of TipDC, and phagocyte killing of yeast. Pharmacological blockade of DppIVA restored leukocyte effector functions and stemmed infection, while addition of recombinant DppIVA to gene-silenced yeast enabled them to evade leukocyte defense. Thus, fungal DppIVA mediates immune-regulatory disturbances that underlie invasive fungal disease. These findings reveal a form of molecular piracy by a broadly conserved aminopeptidase during disease pathogenesis.

  15. Plants as a habitat for beneficial and/or human pathogenic bacteria.

    Science.gov (United States)

    Tyler, Heather L; Triplett, Eric W

    2008-01-01

    Non-plant pathogenic endophytic bacteria can promote plant growth, improve nitrogen nutrition, and, in some cases, are human pathogens. Recent work in several laboratories has shown that enteric bacteria are common inhabitants of the interior of plants. These observations led to the experiments that showed the entry into plants of enteric human pathogens such as Salmonella and E. coli O157:H7. The extent of endophytic colonization by strains is regulated by plant defenses and several genetic determinants necessary for this interior colonization in endophytic bacteria have been identified. The genomes of four endophytic bacteria now available should promote discovery of other genes that contribute to this phenotype. Common virulence factors in plant and animal pathogens have also been described in bacteria that can infect both plant and animal models. Future directions in all of these areas are proposed.

  16. Antimicrobial activity of yeasts against some pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Gamal Younis

    2017-08-01

    Full Text Available Aim: This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species. Materials and Methods: A total of 160 milk and meat products samples were collected from random sellers and super markets in New Damietta city, Damietta, Egypt. Samples were subjected to yeast isolation procedures and tested for its antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In addition, all yeast species isolates were subjected to polymerase chain reaction (PCR for detection of khs (kievitone hydratase and pelA (pectate degrading enzyme genes. Results: The recovery rate of yeasts from sausage was 20% (2/10 followed by kareish cheese, processed cheese, and butter 10% (1/10 each as well as raw milk 9% (9/100, and fruit yoghurt 30% (6/20. Different yeast species were recovered, namely, Candida kefyr (5 isolates, Saccharomyces cerevisiae (4 isolates, Candida intermedia (3 isolates, Candida tropicalis (2 isolates, Candida lusitaniae (2 isolates, and Candida krusei (1 isolate. khs gene was detected in all S. cerevisiae isolates, however, pelA gene was not detected in all identified yeast species. Antimicrobial activity of recovered yeasts against the selected bacterial species showed high activity with C. intermedia against S. aureus and E. coli, C. kefyr against E. coli, and C. lusitaniae against S. aureus. Moderate activities were obtained with C. tropicalis, C. lusitaniae, and S. cerevisiae against E. coli; meanwhile, all the tested yeasts revealed a very low antimicrobial activity against P. aeruginosa. Conclusion: The obtained results confirmed that some kinds of yeasts have the ability to produce antimicrobial compounds that could inhibit some pathogenic and spoilage bacteria and these antimicrobial activity of yeasts enables them to be one of the novel agents in controlling spoilage of food.

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

    Science.gov (United States)

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

    2008-09-01

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

  18. Erythrophore cell response to food‐associated pathogenic bacteria: implications for detection

    Science.gov (United States)

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

    2008-01-01

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

  19. Bacteria isolated from parasitic nematodes--a potential novel vector of pathogens?

    Science.gov (United States)

    Lacharme-Lora, Lizeth; Salisbury, Vyv; Humphrey, Tom J; Stafford, Kathryn; Perkins, Sarah E

    2009-12-21

    Bacterial pathogens are ubiquitous in soil and water - concurrently so are free-living helminths that feed on bacteria. These helminths fall into two categories; the non-parasitic and the parasitic. The former have been the focus of previous work, finding that bacterial pathogens inside helminths are conferred survival advantages over and above bacteria alone in the environment, and that accidental ingestion of non-parasitic helminths can cause systemic infection in vertebrate hosts. Here, we determine the potential for bacteria to be associated with parasitic helminths. After culturing helminths from fecal samples obtained from livestock the external bacteria were removed. Two-hundred parasitic helminths from three different species were homogenised and the bacteria that were internal to the helminths were isolated and cultured. Eleven different bacterial isolates were found; of which eight were indentified. The bacteria identified included known human and cattle pathogens. We concluded that bacteria of livestock can be isolated in parasitic helminths and that this suggests a mechanism by which bacteria, pathogenic or otherwise, can be transmitted between individuals. The potential for helminths to play a role as pathogen vectors poses a potential livestock and human health risk. Further work is required to assess the epidemiological impact of this finding.

  20. Abundance of sewage-pollution indicator and human pathogenic bacteria in a tropical estuarine complex

    Digital Repository Service at National Institute of Oceanography (India)

    Nagvenkar, G.S.; Ramaiah, N.

    Studies on abundance and types of various pollution indicator bacterial populations from tropical estuaries are rare. This study was aimed to estimate current levels of pollution indicator as well as many groups of human pathogenic bacteria...

  1. Aerobic pathogenic bacteria in post-operative wounds at the Moi ...

    African Journals Online (AJOL)

    2002-12-02

    Dec 2, 2002 ... urease, coagulase, triple sugar iron). Disc diffusion ... Results: Staphylococcus aureus species were the most common pathogenic bacteria isolated from the .... inhibition diameter was measured using a transparent ruler and ...

  2. Species-specific dynamic responses of gut bacteria to a mammalian glycan.

    Science.gov (United States)

    Raghavan, Varsha; Groisman, Eduardo A

    2015-05-01

    The mammalian intestine provides nutrients to hundreds of bacterial species. Closely related species often harbor homologous nutrient utilization genes and cocolonize the gut, raising questions regarding the strategies mediating their stable coexistence. Here we reveal that related Bacteroides species that can utilize the mammalian glycan chondroitin sulfate (CS) have diverged in the manner in which they temporally regulate orthologous CS utilization genes. Whereas certain Bacteroides species display a transient surge in CS utilization transcripts upon exposure to CS, other species exhibit sustained activation of these genes. Remarkably, species-specific expression dynamics are retained even when the key players governing a particular response are replaced by those from a species with a dissimilar response. Bacteroides species exhibiting distinct expression behaviors in the presence of CS can be cocultured on CS. However, they vary in their responses to CS availability and to the composition of the bacterial community when CS is the sole carbon source. Our results indicate that diversity resulting from regulation of polysaccharide utilization genes may enable the coexistence of gut bacterial species using a given nutrient. Genes mediating a specific task are typically conserved in related microbes. For instance, gut Bacteroides species harbor orthologous nutrient breakdown genes and may face competition from one another for these nutrients. How, then, does the gut microbial composition maintain such remarkable stability over long durations? We establish that in the case of genes conferring the ability to utilize the nutrient chondroitin sulfate (CS), microbial species vary in how they temporally regulate these genes and exhibit subtle growth differences on the basis of CS availability and community composition. Similarly to how differential regulation of orthologous genes enables related species to access new environments, gut bacteria may regulate the same genes

  3. Signatures of Conformational Stability and Oxidation Resistance in Proteomes of Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Anita Vidovic

    2014-06-01

    Full Text Available Protein oxidation is known to compromise vital cellular functions. Therefore, invading pathogenic bacteria must resist damage inflicted by host defenses via reactive oxygen species. Using comparative genomics and experimental approaches, we provide multiple lines of evidence that proteins from pathogenic bacteria have acquired resistance to oxidative stress by an increased conformational stability. Representative pathogens exhibited higher survival upon HSP90 inhibition and a less-oxidation-prone proteome. A proteome signature of the 46 pathogenic bacteria encompasses 14 physicochemical features related to increasing protein conformational stability. By purifying ten representative proteins, we demonstrate in vitro that proteins with a pathogen-like signature are more resistant to oxidative stress as a consequence of their increased conformational stability. A compositional signature of the pathogens’ proteomes allowed the design of protein fragments more resilient to both unfolding and carbonylation, validating the relationship between conformational stability and oxidability with implications for synthetic biology and antimicrobial strategies.

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

    OpenAIRE

    Janssens, Lizanne; Stoks, Robby

    2014-01-01

    The important ecological role of predation risk in shaping populations, communities and ecosystems is becoming increasingly clear. In this context, synergistic effects between predation risk and other natural stressors on prey organisms are gaining attention. Although non-pathogenic bacteria can be widespread in aquatic ecosystems their role in mediating effects of predation risk has been ignored. We here address the hypothesis that non-pathogenic bacteria may reinforce the negative effects o...

  5. Evolution of temperate pathogens: the bacteriophage/bacteria paradigm

    Directory of Open Access Journals (Sweden)

    Koch Arthur L

    2007-11-01

    Full Text Available Abstract Background Taking as a pattern, the T4 and lambda viruses interacting with each other and with their Gram-negative host, Escherichia coli, a general model is constructed for the evolution of 'gentle' or temperate pathogens. This model is not simply either pure group or kin selection, but probably is common in a variety of host-parasite pairs in various taxonomic groups. The proposed mechanism is that for its own benefit the pathogen evolved ways to protect its host from attack by other pathogens and this has incidentally protected the host. Although appropriate mechanisms would have been developed and excluded related viral species and also other quite different pathogens, the important advance would have been when other individuals of the same species that arrive at the host subsequent to the first infecting one were excluded. Results Such a class of mechanisms would not compete one genotype with another, but simply would be of benefit to the first pathogen that had attacked a host organism. Conclusion This would tend to protect and extend the life of the host against the detrimental effects of a secondarily infecting pathogen. This leads to the pathogens becoming more temperate via the now favorable co-evolution with its host, which basically protects both host and virus against other pathogens but may cause slowing of the growth of the primary infecting pathogen. Evolution by a 'gentle' strategy would be favored as long as the increased wellbeing of the host also favored the eventual transmission of the early infecting pathogen to other hosts.

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

    DEFF Research Database (Denmark)

    Ibfelt, Tobias; Engelund, Eva Hoy; Permin, Anders;

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  8. 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...

  9. Fluorescence techniques to detect and to assess viability of plant pathogenic bacteria

    NARCIS (Netherlands)

    Chitarra, L.G.

    2001-01-01

    Plant pathogenic bacteria cause major economic losses in commercial crop production worldwide every year. The current methods used to detect and to assess the viability of bacterial pathogens and to test seed lots or plants for contamination are usually based on plate assays or on serological techni

  10. Antagonistic activity of antibiotic producing Streptomyces sp. against fish and human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Nazmul Hossain

    2014-04-01

    Full Text Available In this study, attempts were made to isolate Streptomyces sp. from soil samples of two different regions of Bangladesh and evaluate their antagonistic activity against fish and human pathogenic bacteria. A total of 10 isolates were identified as Streptomyces sp. based on several morphological, physiological and biochemical tests. Cross streak method was used to observe the antagonistic activity of the Streptomyces sp. isolates against different fish pathogens belonging to the genus Aeromonas, Pseudomonas and Edwardsiella and human clinical isolates belonging to the genus Klebsiella, Salmonella and Streptococcus. Seven Streptomyces sp. isolates showed antagonism against both fish and human pathogenic bacteria. Four isolates viz., N24, N26, N28 and N47 showed broad spectrum of antagonistic activity (80-100% against all genera of fish and human pathogenic bacteria. The isolate N49 exhibited highest spectrum of antagonism against all fish pathogens (90-100% but comparatively lower degree of antagonism against human pathogens (50-60%. Rest of the two isolates (N21 and N23 showed variability in their antagonism. Results showed that broad spectrum antibiotic(s could be developed from the isolates N24, N26, N28 and N47against several human and fish pathogens. The isolate N49 could be a potential source of antibiotic, especially for fish pathogenic bacteria.

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

    Directory of Open Access Journals (Sweden)

    Wolf-Rainer Abraham

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Vasconcelos Ana

    2010-02-01

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

  13. Natural occurrence and pathogenicity of Xanthomonas bacteria on ...

    African Journals Online (AJOL)

    African Journal of Biotechnology ... Several economical and ornamental plants were assessed for wilting in South and Southwest Ethiopia. ... The pathogenicity of three Xcm isolates to five plant species was tested in a factorial experiment ...

  14. Culturing aerobic and anaerobic bacteria and mammalian cells with a microfluidic differential oxygenator.

    Science.gov (United States)

    Lam, Raymond H W; Kim, Min-Cheol; Thorsen, Todd

    2009-07-15

    In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel network functioning as an oxygen-nitrogen mixer generates differential oxygen concentration. By controlling the relative flow rate of the oxygen and nitrogen input gases, the dissolved oxygen (DO) concentration in proximal microchannels filled with culture media are precisely regulated by molecular diffusion. Sensors consisting of an oxygen-sensitive dye embedded in the fluid channels permit dynamic fluorescence-based monitoring of the DO concentration using low-cost light-emitting diodes. To demonstrate the general utility of the platform for both aerobic and anaerobic culture, three bacteria with differential oxygen requirements (E. coli, A. viscosus, and F. nucleatum), as well as a model mammalian cell line (murine embryonic fibroblast cells (3T3)), were cultured. Growth characteristics of the selected species were analyzed as a function of eight discrete DO concentrations, ranging from 0 ppm (anaerobic) to 42 ppm (fully saturated).

  15. The specificationof nano-structure superficial layers in some of the pathogen bacteria

    Directory of Open Access Journals (Sweden)

    Shilla Jalalpoor

    2010-11-01

    Full Text Available Background: The superficial layer is a part of the cellular envelop that is seen in bacteria and archaea. This superficial layer is a single layer structure composed of subordinate proteins or glycoproteins. The superficial layer is the outer most cellular structure that is in the exchange and reaction around environment with bacteria. This structure has very diversity in bacteria different types.Materials and Method: The related articles to superficial layer were extracted of these articles: Pubmed, Elsevier Science, and Yahoo, from 1995 to 2010 years. For this purpose keywords were searched including superficial layer, pathogenesis, pathogen bacteria,Results: There is consensus in the case of the superficial layer and about the existence of this superficial structure lead to increased pathogenesis in bacteria, in all of the research articles.Conclusion: S-layers in pathogen bacteria with bacteria protection against bacteriophages and phagocytosis, resistance against low pH, adhesion, stabilisation of the membrane and providing adhesion sites for exoproteins caused pathogenesis, infection resistant and antibiotic resistant in host.The result of this study shows the prevalence of considerable S-layer in pathogen bacteria and this matter identified the bacteria generator importance of this structure in the laboratory

  16. A reservoir of drug-resistant pathogenic bacteria in asymptomatic hosts.

    Directory of Open Access Journals (Sweden)

    Gabriel G Perron

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

  17. Tissue-specific activities of an immune signaling module regulate physiological responses to pathogenic and nutritional bacteria in C. elegans.

    Science.gov (United States)

    Shivers, Robert P; Kooistra, Tristan; Chu, Stephanie W; Pagano, Daniel J; Kim, Dennis H

    2009-10-22

    Microbes represent both an essential source of nutrition and a potential source of lethal infection to the nematode Caenorhabditis elegans. Immunity in C. elegans requires a signaling module comprised of orthologs of the mammalian Toll-interleukin-1 receptor (TIR) domain protein SARM, the mitogen-activated protein kinase kinase kinase (MAPKKK) ASK1, and MAPKK MKK3, which activates p38 MAPK. We determined that the SARM-ASK1-MKK3 module has dual tissue-specific roles in the C. elegans response to pathogens--in the cell-autonomous regulation of innate immunity and the neuroendocrine regulation of serotonin-dependent aversive behavior. SARM-ASK1-MKK3 signaling in the sensory nervous system also regulates egg-laying behavior that is dependent on bacteria provided as a nutrient source. Our data demonstrate that these physiological responses to bacteria share a common mechanism of signaling through the SARM-ASK1-MKK3 module and suggest the co-option of ancestral immune signaling pathways in the evolution of physiological responses to microbial pathogens and nutrients.

  18. STUDY ON ADHERENCE ABILITY OF PERIODONTAL PATHOGENS AND CARIOGENIC BACTERIA TO HYDROXYAPATITE DISKS

    Institute of Scientific and Technical Information of China (English)

    WANG Min-feng; LI De-yi; LI Zong-lin

    2006-01-01

    Objective To study the adherence activity of six representative periodontopathic and cariogenic bacteria to hydroxyapatite disks. Methods Six periodontopathic and cariogenic bacteria of P. gingivalis, A.actinomycetemcomitans, F. nucleatum, S. sanguis, A. viscosus and S. mutans were cultured in modified MD-300 chemostat according to total fifteen experimental groups of single-specie and each pair of periodontal pathogens and cariogenic bacteria, respectively. After 1h attached live bacteria on removable hydroxyapatite disks was analyzed by culture technologies to evaluate the adherence level. Results The adherence activity of periodontopathic and cariogenic bacteria to HA was in the following order: S. sanguis > A. viscosus > S. mutans > A. actinomycetemcomitans > F. nucleatum > P. gingivalis. The number of periodontopathic bacteria to HA was enhanced by S.sanguis and A. viscosus, respectively. When mix-cultivated with S. mutans, the colonization of P. gingivalis was reduced significantly( P<0.001 ). Periodontopathic bacteria had no effect on the adherence activity of S. mutans and A. viscosus, except S. sanguis. Conclusion It was showed that the adherence activity of periodontal pathogens was weaker than that of cariogenic bacteria and emphasized the importance of bacterial adherence in determining the level of bacterial colonization on tooth surfaces. It was suggested that periodontopathic bacteria can utilize initial colonizers to become those predominant bacteria in periodontal ecosystem, which maybe have close relation to the periodontopathic mechanism.

  19. DNA extraction protocol for rapid PCR detection of pathogenic bacteria

    Science.gov (United States)

    Virtually all current assays for foodborne pathogens, including PCR assays, are conducted after lengthy cultural enrichment of the sample to increase the concentration of the target organism. This delays detection by many hours, prevents quantitation, and limits the ability to detect multiple organ...

  20. 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

  1. High inorganic triphosphatase activities in bacteria and mammalian cells: identification of the enzymes involved.

    Directory of Open Access Journals (Sweden)

    Gregory Kohn

    Full Text Available BACKGROUND: We recently characterized a specific inorganic triphosphatase (PPPase from Nitrosomonas europaea. This enzyme belongs to the CYTH superfamily of proteins. Many bacterial members of this family are annotated as predicted adenylate cyclases, because one of the founding members is CyaB adenylate cyclase from A. hydrophila. The aim of the present study is to determine whether other members of the CYTH protein family also have a PPPase activity, if there are PPPase activities in animal tissues and what enzymes are responsible for these activities. METHODOLOGY/PRINCIPAL FINDINGS: Recombinant enzymes were expressed and purified as GST- or His-tagged fusion proteins and the enzyme activities were determined by measuring the release of inorganic phosphate. We show that the hitherto uncharacterized E. coli CYTH protein ygiF is a specific PPPase, but it contributes only marginally to the total PPPase activity in this organism, where the main enzyme responsible for hydrolysis of inorganic triphosphate (PPP(i is inorganic pyrophosphatase. We further show that CyaB hydrolyzes PPP(i but this activity is low compared to its adenylate cyclase activity. Finally we demonstrate a high PPPase activity in mammalian and quail tissue, particularly in the brain. We show that this activity is mainly due to Prune, an exopolyphosphatase overexpressed in metastatic tumors where it promotes cell motility. CONCLUSIONS AND GENERAL SIGNIFICANCE: We show for the first time that PPPase activities are widespread in bacteria and animals. We identified the enzymes responsible for these activities but we were unable to detect significant amounts of PPP(i in E. coli or brain extracts using ion chromatography and capillary electrophoresis. The role of these enzymes may be to hydrolyze PPP(i, which could be cytotoxic because of its high affinity for Ca(2+, thereby interfering with Ca(2+ signaling.

  2. Rainbow trout (Oncorhynchus mykiss) secretory component binds to commensal bacteria and pathogens.

    Science.gov (United States)

    Kelly, Cecelia; Takizawa, Fumio; Sunyer, J Oriol; Salinas, Irene

    2017-02-02

    Commensal bacteria co-exist on the mucosal surfaces of all vertebrates. The host's mucosal immune system must tolerate commensals while fighting pathogens. One of the mechanisms used by the mucosal immune system to maintain homeostasis is the secretion of immunoglobulins (Igs) across epithelial barriers, which is achieved via the polymeric immunoglobulin receptor (pIgR). Rainbow trout pIgR is known to transport IgT and IgM across epithelia. However, other biological functions for trout pIgR or trout secretory component (tSC) remain unknown. This study investigates the interaction of tSC with commensal bacteria, pathogenic bacteria and a fungal pathogen. Our results show that the majority of trout skin and gut bacteria are coated in vivo by tSC. In vitro, tSC present in mucus coats trout commensal isolates such as Microbacterium sp., Staphylococcus warneri, Flectobacillus major, Arthrobacter stackebrantii, and Flavobacterium sp. and the pathogens Vibrio anguillarum and Edwardsiella ictaluri with coating levels ranging from 8% to 70%. Moreover, we found that the majority of tSC is in free form in trout mucus and free tSC is able to directly bind bacteria. We propose that binding of free SC to commensal bacteria is a key and conserved mechanism for maintenance of microbial communities in vertebrate mucosal surfaces.

  3. Antimicrobial Potential Of Azadirachta Indica Against Pathogenic Bacteria And Fungi

    Directory of Open Access Journals (Sweden)

    Mohammad Asif

    2012-11-01

    Full Text Available Drugs from natural sources are used for treating various diseases since the ancient times. From the literature it is clear that various type of pharmacological and biological activities are associated with Azadirachta indica. Theleave oil of A. indica is known to have good antimicrobial potential. The oil of A. indica leaves, was tested against the different infectious microorganisms [Gram positive bacteria and Gram-negative bacteria], such as bacterial strains; S. aureus, E. coli, B. cerus, P. vulgaris, S. typhi, K. pneumonae, S. dysenterae and Fungal strains; F. oxysporum, A. flavus, A. fumigates, A. niger, C. albicans, Cladosporium sp., M. canis, M. gypseum, T. rubrum, T. mentagrophytes, P. notatum and P. citrinum etc.The results showed that level of antimicrobial activities of the A.indica oil depends on both the protein and carbohydrate contents. Generally, the high level of protein and carbohydrate contents of extract had better antimicrobial activities.

  4. Genomic research for important pathogenic bacteria in China

    Institute of Scientific and Technical Information of China (English)

    YANG RuiFu; GUO XiaoKui; YANG Jian; JIANG YongQiang; PANG Bo; CHEN Chen; YAO YuFeng; QIN JinHong; LI QingTian

    2009-01-01

    Rapid accumulation of bacterial genomic data offered an unprecedented opportunity to understand bacterial biology from a holistic view of point. We can thus closely look at the way in which a pathogen is evolved, and these data has been applied to molecular epidemiology and microbial forensics, and screening of novel diagnostic, vaccine and drug targets. The newly developed high-throughput low-cost sequencing technologies, such as 454, Solexa and SOLiD, will promote the acquisition and application of genomic data in new research areas that we dared not imagine previously, such as the metagenomics of human gastric-intestinal tract, for better and comprehensive understanding of human health and disease.

  5. A mathematical model for removal of human pathogenic viruses and bacteria by slow sand filtration under variable operational conditions

    NARCIS (Netherlands)

    Schijven, J.F.; Berg, H.H.J.L. van den; Colin, M.; Dullemont, Y.; Hijnen, W.A.M.; Magic-Knezev, A.; Oorthuizen, W.A.; Wubbels, G.

    2013-01-01

    Slow sand filtration (SSF) in drinking water production removes pathogenic microorganisms, but detection limits and variable operational conditions complicate assessment of removal efficiency. Therefore, amodel was developed to predict removal ofhuman pathogenic viruses and bacteria as a function of

  6. Children with asthma by school age display aberrant immune responses to pathogenic airway bacteria as infants

    DEFF Research Database (Denmark)

    Larsen, Jeppe Madura; Pedersen, Susanne Brix; Thysen, Anna Hammerich

    2014-01-01

    childhood asthma. We hypothesized that children with asthma have an abnormal immune response to pathogenic bacteria in infancy. ObjectiveWe aimed to assess the bacterial immune response in asymptomatic infants and the association with later development of asthma by age 7 years. MethodsThe Copenhagen...... (P = .001), and IL-10 (P = .028), whereas there were no differences in T-cell activation or peripheral T-cell composition. ConclusionsChildren with asthma by school age exhibited an aberrant immune response to pathogenic bacteria in infancy. We propose that an abnormal immune response to pathogenic......BackgroundAsthma is a highly prevalent chronic lung disease that commonly originates in early childhood. Colonization of neonatal airways with the pathogenic bacterial strains Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae is associated with increased risk of later...

  7. Disinfection and removal of human pathogenic bacteria in arctic waste stabilization ponds

    DEFF Research Database (Denmark)

    Huang, Yannan; Hansen, Lisbeth Truelstrup; Ragush, Colin M.

    2017-01-01

    Wastewater stabilization ponds (WSPs) are commonly used to treat municipal wastewater in Arctic Canada. The biological treatment in the WSPs is strongly influenced by climatic conditions. Currently, there is limited information about the removal of fecal and pathogenic bacteria during the short...... cool summer treatment season. With relevance to public health, the objectives of this paper were to determine if treatment in arctic WSPs resulted in the disinfection (i.e., removal of fecal indicator bacteria, Escherichia coli) and removal of selected human bacterial pathogens from the treated...... treatment of the wastewater with a 2–3 Log removal of generic indicator E. coli. The bacterial pathogens Salmonella spp., pathogenic E. coli, and Listeria monocytogenes, but not Campylobacter spp. and Helicobacter pylori, were detected in the untreated and treated wastewater, indicating that human...

  8. A multifunctional probe with aggregation-induced emission characteristics for selective fluorescence imaging and photodynamic killing of bacteria over mammalian cells.

    Science.gov (United States)

    Gao, Meng; Hu, Qinglian; Feng, Guangxue; Tomczak, Nikodem; Liu, Rongrong; Xing, Bengang; Tang, Ben Zhong; Liu, Bin

    2015-04-02

    A multifunctional probe aggregation-induced emission-Zinc(II)-dipicolylamine (AIE-ZnDPA) is developed for selective targeting, fluorescence imaging, and photodynamic killing of both Gram-positive and Gram-negative bacteria over mammalian cells. The probe has significant advantages in simple probe design, enhanced fluorescence upon bacteria binding, excellent photostability, and broad-spectrum antibacterial activity with almost no harm to mammalian cells.

  9. Cell signaling in the interaction between pathogenic bacteria and immune cells.

    Science.gov (United States)

    Yang, Hui; Liu, Yaxiong; Tang, Ruihua; Shao, Dongyan; Li, Jing; Li, Ji; Ye, Linjie; Jin, Mingliang; Huang, Qingsheng; Shi, Junling

    2015-06-01

    Cell signaling is an essential part in the complex system of communication that governs basic cellular activities and coordinates cell actions. The ability of cells to perceive and correctly respond to their microenvironment is essential for cell survival and basic biological function. In the defense from pathogenic bacteria, the immune cells exert their function through various signaling pathways. In this review, we will summarize recent findings on the role of cell signaling in the interaction between pathogenic bacteria and immune cells, focusing on neutrophils and macrophages, which are part of the innate immunity, and also T cells, which are components of the adaptive immune system.

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

    Science.gov (United States)

    Poshtiban, Somayyeh

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

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

    Science.gov (United States)

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

    2012-01-01

    Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary. PMID:22705866

  12. Frost related dieback in Estonian energy plantations of willows in relation to fertilisation and pathogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cambours, M.A.; Nejad, P. [Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, 750 07 Uppsala (Sweden); Heinsoo, K. [Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, 51014 Tartu (Estonia); Granhall, U. [Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala (Sweden)

    2006-03-15

    Two 9-year old Estonian Salix plantations suffering from dieback were studied: one situated on poor mineral soil and divided into fertilised and unfertilised plots (Saare plantation) and another growing on a well-decomposed and nitrogen-rich organic soil, without fertiliser application (Kambja plantation). Bacteria from internal tissues of visually damaged shoots from seven clones were isolated in spring and autumn. The strains were subsequently biochemically characterised and tested for ice nucleation activity and pathogenicity on Salix. Some strains were also analysed with 16S rRNA. High numbers of culturable bacteria were found, belonging mainly to Erwinia, Sphingomonas, Pseudomonas and Xanthomonas spp. Fertilised plots were significantly more colonised by bacteria than unfertilised plots and also more extensively damaged, showing a lower density of living plants after 7 years of culture. More ice nucleation active (INA) strains were found in Saare fertilised plots and at Kambja than in Saare unfertilised plots. Likewise, most pathogenic strains were isolated from Saare fertilised plots and from Kambja. For some of the willow clones studied, dieback appeared to be related to both clonal frost sensitivity and abundance of INA and pathogenic bacteria. The plantations probably suffered from the presence of high amounts of pathogens and from frost related injuries aggravated by INA bacteria. Most probably the fertilisation at Saare and the nitrogen-rich soil at Kambja created a favourable environment for bacterial development and led to high dieback levels after the first harvest. (author)

  13. Prevalence of plant beneficial and human pathogenic bacteria isolated from salad vegetables in India.

    Science.gov (United States)

    Nithya, Angamuthu; Babu, Subramanian

    2017-03-14

    The study aimed at enumerating, identifying and categorizing the endophytic cultivable bacterial community in selected salad vegetables (carrot, cucumber, tomato and onion). Vegetable samples were collected from markets of two vegetable hot spot growing areas, during two different crop harvest seasons. Crude and diluted vegetable extracts were plated and the population of endophytic bacteria was assessed based on morphologically distinguishable colonies. The bacterial isolates were identified by growth in selective media, biochemical tests and 16S rRNA gene sequencing. The endophytic population was found to be comparably higher in cucumber and tomato in both of the sampling locations, whereas lower in carrot and onion. Bacterial isolates belonged to 5 classes covering 46 distinct species belonging to 19 genera. Human opportunistic pathogens were predominant in carrot and onion, whereas plant beneficial bacteria dominated in cucumber and tomato. Out of the 104 isolates, 16.25% are human pathogens and 26.5% are human opportunistic pathogens. Existence of a high population of plant beneficial bacteria was found to have suppressed the population of plant and human pathogens. There is a greater potential to study the native endophytic plant beneficial bacteria for developing them as biocontrol agents against human pathogens that are harboured by plants.

  14. AOTF hyperspectral microscopic imaging for foodborne pathogenic bacteria detection

    Science.gov (United States)

    Park, Bosoon; Lee, Sangdae; Yoon, Seung-Chul; Sundaram, Jaya; Windham, William R.; Hinton, Arthur, Jr.; Lawrence, Kurt C.

    2011-06-01

    Hyperspectral microscope imaging (HMI) method which provides both spatial and spectral information can be effective for foodborne pathogen detection. The AOTF-based hyperspectral microscope imaging method can be used to characterize spectral properties of biofilm formed by Salmonella enteritidis as well as Escherichia coli. The intensity of spectral imagery and the pattern of spectral distribution varied with system parameters (integration time and gain) of HMI system. The preliminary results demonstrated determination of optimum parameter values of HMI system and the integration time must be no more than 250 ms for quality image acquisition from biofilm formed by S. enteritidis. Among the contiguous spectral imagery between 450 and 800 nm, the intensity of spectral images at 498, 522, 550 and 594 nm were distinctive for biofilm; whereas, the intensity of spectral images at 546 nm was distinctive for E. coli. For more accurate comparison of intensity from spectral images, a calibration protocol, using neutral density filters and multiple exposures, need to be developed to standardize image acquisition. For the identification or classification of unknown food pathogen samples, ground truth regions-of-interest pixels need to be selected for "spectrally pure fingerprints" for the Salmonella and E. coli species.

  15. Antibacterial activity of different honeys against pathogenic bacteria.

    Science.gov (United States)

    Voidarou, C; Alexopoulos, A; Plessas, S; Karapanou, A; Mantzourani, I; Stavropoulou, E; Fotou, K; Tzora, A; Skoufos, I; Bezirtzoglou, E

    2011-12-01

    To study the antimicrobial activity of honey, 60 samples of various botanical origin were evaluated for their antimicrobial activities against 16 clinical pathogens and their respective reference strains. The microbiological quality of honeys and the antibiotic susceptibility of the various isolates were also examined. The bioassay applied for determining the antimicrobial effect employs the well-agar diffusion method and the estimation of minimum active dilution which produces a 1mm diameter inhibition zone. All honey samples, despite their origin (coniferous, citrus, thyme or polyfloral), showed antibacterial activity against the pathogenic and their respective reference strains at variable levels. Coniferous and thyme honeys showed the highest activity with an average minimum dilution of 17.4 and 19.2% (w/v) followed by citrus and polyfloral honeys with 20.8 and 23.8% respectively. Clinical isolates of Staphylococcus aureus subsp. aureus, Escherichia coli, Salmonella enterica subsp. Enterica, Streptococcus pyogenes, Bacillus cereus and Bacillus subtilis were proven to be up to 60% more resistant than their equal reference strains thus emphasizing the variability in the antibacterial effect of honey and the need for further research. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Identification and Pathogenicity of Phytopathogenic Bacteria Associated with Soft Rot Disease of Girasole Tuber

    OpenAIRE

    Mamdoh Ewis ISMAIL; Abdel-Monaim, Montaser Fawzy; Yasser Mahmoud MOSTAFA

    2012-01-01

    During 2010-2011 growing seasons six bacterial isolates were separated from naturally infected girasole plants tubers (Helianthus tuberosus L.) cv. �Balady�, showing soft rot, collected from experimental Farm of the Faculty of Agriculture, in El-Minia University, Egypt. Pathogenicity tests showed various virulence for the bacteria isolated from girasole tubers, found pathogenic. These organisms were characterized as rod-shaped, Gram negative, ?-methyl-d-glucoside medium, reducing substances f...

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

    Science.gov (United States)

    Dankevich, L A

    2013-01-01

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

  18. Long-Term Storage of Plant-Pathogenic Bacteria in Sterile Distilled Water

    OpenAIRE

    Nicola S. Iacobellis; DeVay, James E.

    1986-01-01

    This study was made to determine the effectiveness of the preservation of plant-pathogenic bacteria in sterile distilled water. After 20 or 24 years of storage in distilled water, a very high percentage (90 to 92%) of the isolates of Agrobacterium tumefaciens and Pseudomonas spp. were still alive. Moreover, 12 of 13 viable (after 24 years) isolates of P. syringae subsp. syringae maintained their ability to produce syringomycin and were pathogenic to bean seedlings. The water-stored cells of t...

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

    Directory of Open Access Journals (Sweden)

    Thandavarayan eRamamurthy

    2014-07-01

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

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

    Science.gov (United States)

    Tampakaki, Anastasia P

    2014-01-01

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

  1. The production and detoxification of a potent cytotoxin, nitric oxide, by pathogenic enteric bacteria.

    Science.gov (United States)

    Arkenberg, Anke; Runkel, Sebastian; Richardson, David J; Rowley, Gary

    2011-12-01

    The nitrogen cycle is based on several redox reactions that are mainly accomplished by prokaryotic organisms, some archaea and a few eukaryotes, which use these reactions for assimilatory, dissimilatory or respiratory purposes. One group is the Enterobacteriaceae family of Gammaproteobacteria, which have their natural habitats in soil, marine environments or the intestines of humans and other warm-blooded animals. Some of the genera are pathogenic and usually associated with intestinal infections. Our body possesses several physical and chemical defence mechanisms to prevent pathogenic enteric bacteria from invading the gastrointestinal tract. One response of the innate immune system is to activate macrophages, which produce the potent cytotoxin nitric oxide (NO). However, some pathogens have evolved the ability to detoxify NO to less toxic compounds, such as the neuropharmacological agent and greenhouse gas nitrous oxide (N₂O), which enables them to overcome the host's attack. The same mechanisms may be used by bacteria producing NO endogenously as a by-product of anaerobic nitrate respiration. In the present review, we provide a brief introduction into the NO detoxification mechanisms of two members of the Enterobacteriaceae family: Escherichia coli and Salmonella enterica serovar Typhimurium. These are discussed as comparative non-pathogenic and pathogenic model systems in order to investigate the importance of detoxifying NO and producing N₂O for the pathogenicity of enteric bacteria.

  2. Interactions of some common pathogenic bacteria with Acanthamoeba polyphaga.

    Science.gov (United States)

    Huws, Sharon A; Morley, Robert J; Jones, Martin V; Brown, Michael R W; Smith, Anthony W

    2008-05-01

    Protozoan grazing is a major trophic pathway whereby the biomass re-enters the food web. Nonetheless, not all bacteria are digested by protozoa and the number known to evade digestion, resulting in their environmental augmentation, is increasing. We investigated the interactions of Bacillus cereus, Enterococcus faecalis, Enteropathogenic Escherichia coli (EPEC), Listeria monocytogenes, Salmonella enterica serovar Typhimurium, and methicillin-sensitive Staphylococcus aureus (MSSA), with the amoeba, Acanthamoeba polyphaga. There was evidence of predation of all bacterial species except L. monocytogenes and S. aureus, where extracellular numbers were significantly higher when cultured with amoebae compared with growth in the absence of amoebae. Intracellular growth kinetic experiments and fluorescent confocal microscopy suggest that S. aureus survived and may even multiply within A. polyphaga, whereas there was no apparent intra-amoebal replication of L. monocytogenes and higher numbers were likely sustained on metabolic waste products released during coculture.

  3. Vaccines based on the cell surface carbohydrates of pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Jones Christopher

    2005-01-01

    Full Text Available Glycoconjugate vaccines, in which a cell surface carbohydrate from a micro-organism is covalently attached to an appropriate carrier protein are proving to be the most effective means to generate protective immune responses to prevent a wide range of diseases. The technology appears to be generic and applicable to a wide range of pathogens, as long as antibodies against surface carbohydrates help protect against infection. Three such vaccines, against Haemophilus influenzae type b, Neisseria meningitidis Group C and seven serotypes of Streptococcus pneumoniae, have already been licensed and many others are in development. This article discusses the rationale for the development and use of glycoconjugate vaccines, the mechanisms by which they elicit T cell-dependent immune responses and the implications of this for vaccine development, the role of physicochemical methods in the characterisation and quality control of these vaccines, and the novel products which are under development.

  4. DNA extraction protocol for rapid PCR detection of pathogenic bacteria.

    Science.gov (United States)

    Brewster, Jeffrey D; Paoli, George C

    2013-11-01

    Twelve reagents were evaluated to develop a direct DNA extraction method suitable for PCR detection of foodborne bacterial pathogens. Many reagents exhibited strong PCR inhibition, requiring significant dilution of the extract with a corresponding reduction in sensitivity. Most reagents also exhibited much lower recovery of DNA from the gram-positive test organism (Listeria monocytogenes) than from the gram-negative organism (Escherichia coli O157:H7), preventing unbiased detection and quantitation of both organisms. The 5× HotSHOT+Tween reagent exhibited minimal inhibition and high extraction efficiency for both test organisms, providing a 15-min single-tube DNA-extraction protocol suitable for highly sensitive quantitative PCR assays. Published by Elsevier Inc.

  5. Genomic research for important pathogenic bacteria in China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Rapid accumulation of bacterial genomic data offered an unprecedented opportunity to understand bacterial biology from a holistic view of point.We can thus closely look at the way in which a pathogen is evolved,and these data has been applied to molecular epidemiology and microbial forensics,and screening of novel diagnostic,vaccine and drug targets.The newly developed high-throughput low-cost sequencing technologies,such as 454,Solexa and SOLiD,will promote the acquisition and application of genomic data in new research areas that we dared not imagine previously,such as the metagenomics of human gastric-intestinal tract,for better and comprehensive understanding of human health and disease.

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

    Science.gov (United States)

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

    2013-01-01

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

  7. Adhesion to the yeast cell surface as a mechanism for trapping pathogenic bacteria by Saccharomyces probiotics.

    Science.gov (United States)

    Tiago, F C P; Martins, F S; Souza, E L S; Pimenta, P F P; Araujo, H R C; Castro, I M; Brandão, R L; Nicoli, Jacques R

    2012-09-01

    Recently, much attention has been given to the use of probiotics as an adjuvant for the prevention or treatment of gastrointestinal pathology. The great advantage of therapy with probiotics is that they have few side effects such as selection of resistant bacteria or disturbance of the intestinal microbiota, which occur when antibiotics are used. Adhesion of pathogenic bacteria onto the surface of probiotics instead of onto intestinal receptors could explain part of the probiotic effect. Thus, this study evaluated the adhesion of pathogenic bacteria onto the cell wall of Saccharomyces boulardii and Saccharomyces cerevisiae strains UFMG 905, W303 and BY4741. To understand the mechanism of adhesion of pathogens to yeast, cell-wall mutants of the parental strain of Saccharomyces cerevisiae BY4741 were used because of the difficulty of mutating polyploid yeast, as is the case for Saccharomyces cerevisiae and Saccharomyces boulardii. The tests of adhesion showed that, among 11 enteropathogenic bacteria tested, only Escherichia coli, Salmonella Typhimurium and Salmonella Typhi adhered to the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741. The presence of mannose, and to some extent bile salts, inhibited this adhesion, which was not dependent on yeast viability. Among 44 cell-wall mutants of Saccharomyces cerevisiae BY4741, five lost the ability to fix the bacteria. Electron microscopy showed that the phenomenon of yeast-bacteria adhesion occurred both in vitro and in vivo (in the digestive tract of dixenic mice). In conclusion, some pathogenic bacteria were captured on the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741, thus preventing their adhesion to specific receptors on the intestinal epithelium and their subsequent invasion of the host.

  8. White Band Disease (type I) of endangered caribbean acroporid corals is caused by pathogenic bacteria.

    Science.gov (United States)

    Kline, David I; Vollmer, Steven V

    2011-01-01

    Diseases affecting coral reefs have increased exponentially over the last three decades and contributed to their decline, particularly in the Caribbean. In most cases, the responsible pathogens have not been isolated, often due to the difficulty in isolating and culturing marine bacteria. White Band Disease (WBD) has caused unprecedented declines in the Caribbean acroporid corals, resulting in their listings as threatened on the US Threatened and Endangered Species List and critically endangered on the IUCN Red List. Yet, despite the importance of WBD, the probable pathogen(s) have not yet been determined. Here we present in situ transmission data from a series of filtrate and antibiotic treatments of disease tissue that indicate that WBD is contagious and caused by bacterial pathogen(s). Additionally our data suggest that Ampicillin could be considered as a treatment for WBD (type I).

  9. Antimicrobial activity of medicinal plant leaf extracts against pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Atikya Farjana

    2014-09-01

    Full Text Available Objective: To determine antibacterial activity of water, oil and methanol extracts of guava (Psidium guajava, green tea (Camellia sinensis, neem (Azadirachta indica and marigold (Calendula officinalis against different species of bacteria, Pseudomonas spp., Vibrio cholerae, Vibrio parahaemolyticus (V. parahaemolyticus, Klebsiella spp., Escherichia coli, Salmonella spp. and Staphylococcus aureus (S. aureus. Methods: Antibacterial activity of plant extracts was measured by agar well diffusion method. Results: Boiled water extracts of guava leaf showed the largest zone of inhibition (22 mm against V. parahaemolyticus. Water extracts of green tea leaf at boiling and room temperature showed 17.5 mm and 19 mm zone of inhibitions against V. parahaemolyticus and S. aureus, respectively. Boiled water extract of neem leaf showed moderate zone of inhibition against Escherichia coli (10 mm and Klebsiella spp. (11 mm. Water and oil extracts of marigold leaf at both boiling and room temperature did not show any zone of inhibition against any of the tested microorganisms. Methanol extracts of both guava and green tea leaves showed same zone of inhibition against Pseudomonus spp. (18 mm. Methanol extract of neem leaf showed antibacterial acitivity against Klebsiella spp. (16 mm and Vibrio cholerae (14 mm and that of marigold leaf showed antimicrobial activity against S. aureus (18 mm and Klebsiella spp. (12 mm. Conclusions: The results from the study suggest that the leaves of guava, green tea, neem and marigold show anibacterial activity against different bacterial species. They could be used as alternatives to common antimicrobial agents for treatment of bacterial infections.

  10. Inverted methoxypyridinium phthalocyanines for PDI of pathogenic bacteria.

    Science.gov (United States)

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

    2015-10-01

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

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

    Science.gov (United States)

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

    2013-05-31

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

  12. Functional Diversity of Tandem Substrate-Binding Domains in ABC Transporters from Pathogenic Bacteria

    NARCIS (Netherlands)

    Fulyani, Faizah; Schuurman-Wolters, Gea K.; Vujicic - Zagar, Andreja; Guskov, Albert; Slotboom, Dirk-Jan; Poolman, Bert

    2013-01-01

    The ATP-binding cassette (ABC) transporter GInPQ is an essential uptake system for amino acids in gram-positive pathogens and related nonpathogenic bacteria. The transporter has tandem substrate-binding domains (SBDs) fused to each transmembrane domain, giving rise to four SBDs per functional transp

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2008-01-01

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

  16. A preliminary study on the pathogenicity of Bacillus licheniformis bacteria in immunodepressed mice

    DEFF Research Database (Denmark)

    Agerholm, J.S.; Jensen, N.E.; Giese, Steen Bjørck

    1997-01-01

    The pathogenicity of 13 strains of Bacillus licheniformis was studied in immunodepressed mice. The strains had been isolated from cases of bovine abortions (n=5), bovine feedstuffs (n=3), soil (n=l), and grain products (n=2). The origin of two strains was unknown. Groups of 10 mice were inoculate...... intravenously with B. licheniformis bacteria at doses from...

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

    Science.gov (United States)

    Current microbial source tracking (MST) methods for water depend on testing for fecal indicator bacterial counts or specific marker gene sequences to identify fecal contamination where potential human pathogenic bacteria could be present. In this study, we applied 454 high-throughput pyrosequencing ...

  18. 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. ...

  19. Molecular detection of plant pathogenic bacteria using polymerase chain reaction single-strand conformation polymorphism.

    Science.gov (United States)

    Srinivasa, Chandrashekar; Sharanaiah, Umesha; Shivamallu, Chandan

    2012-03-01

    The application of polymerase chain reaction (PCR) technology to molecular diagnostics holds great promise for the early identification of agriculturally important plant pathogens. Ralstonia solanacearum, Xanthomoans axonopodis pv. vesicatoria, and Xanthomonas oryzae pv. oryzae are phytopathogenic bacteria, which can infect vegetables, cause severe yield loss. PCR-single-strand conformation polymorphism (PCR-SSCP) is a simple and powerful technique for identifying sequence changes in amplified DNA. The technique of PCR-SSCP is being exploited so far, only to detect and diagnose human bacterial pathogens in addition to plant pathogenic fungi. Selective media and serology are the commonly used methods for the detection of plant pathogens in infected plant materials. In this study, we developed PCR-SSCP technique to identify phytopathogenic bacteria. The PCR product was denatured and separated on a non-denaturing polyacrylamide gel. SSCP banding patterns were detected by silver staining of nucleic acids. We tested over 56 isolates of R. solanacearum, 44 isolates of X. axonopodis pv. vesicatoria, and 20 isolates of X. oryzae pv. oryzae. With the use of universal primer 16S rRNA, we could discriminate such species at the genus and species levels. Species-specific patterns were obtained for bacteria R. solanacearum, X. axonopodis pv. vesicatoria, and X. oryzae pv. oryzae. The potential use of PCR-SSCP technique for the detection and diagnosis of phytobacterial pathogens is discussed in the present paper.

  20. Molecular detection of plant pathogenic bacteria using polymerase chain reaction single-strand conformation polymorphism

    Institute of Scientific and Technical Information of China (English)

    Chandrashekar Srinivasa; Umesha Sharanaiah; Chandan Shivamallu

    2012-01-01

    The application of polymerase chain reaction (PCR) technology to molecular diagnostics holds great promise for the early identification of agriculturally important plant pathogens.Ralstonia solanacearum,Xanthomoans axonopodis pv.vesicatoria,and Xanthomonas oryzae pv.oryzae are phytopathogenic bacteria,which can infect vegetables,cause severe yield loss.PCR-single-strand conformation polymorphism (PCR-SSCP) is a simple and powerful technique for identifying sequence changes in amplified DNA.The technique of PCR-SSCP is being exploited so far,only to detect and diagnose human bacterial pathogens in addition to plant pathogenic fungi.Selective media and serology are the commonly used methods for the detection of plant pathogens in infected plant materials.In this study,we developed PCR-SSCP technique to identify phytopathogenic bacteria.The PCR product was denatured and separated on a non-denaturing polyacrylamide gel.SSCP banding patterns were detected by silver staining of nucleic acids.We tested over 56 isolates of R. solanacearum,44 isolates of X. axonopodis pv.vesicatoria,and 20 isolates of X.oryzae pv.oryzae.With the use of universal primer 16S rRNA,we could discriminate such species at the genus and species levels.Speciesspecific patterns were obtained for bacteria R.solanacearum,X.axonopodis pv.vesicatoria,and X.oryzae pv.oryzae.The potential use of PCR-SSCP technique for the detection and diagnosis of phytobacterial pathogens is discussed in the present paper.

  1. A novel plasmid for delivering genes into mammalian cells with noninvasive food and commensal lactic acid bacteria.

    Science.gov (United States)

    Tao, Lin; Pavlova, Sylvia I; Ji, Xin; Jin, Ling; Spear, Gregory

    2011-01-01

    Using food and commensal lactic acid bacteria (LAB) as vehicles for DNA delivery into epithelial cells is a new strategy for vaccine delivery or gene therapy. However, present methods for DNA delivery with LAB have suffered low efficiency. Our goal was to develop a new system to deliver DNA into epithelial cells with high efficiency using food and commensal LAB. An Escherichia coli-LAB shuttle plasmid, pLKV1, for DNA delivery into eukaryotic cells was constructed. Two reporter plasmids with green and red fluorescent protein genes were also constructed to monitor the uptake of protein and DNA, respectively. Bacteria delivering these reporter plasmids into Caco-2 cells were monitored by fluorescence microscopy. Several methods that weaken the bacterial cell wall prior to co-culture with Caco-2 cells were evaluated for their role in the improvement of gene transfer efficiency. Treating Streptococcus gordonii with penicillin and lysozyme greatly increased its rate of gene delivery to mammalian cells compared to untreated control bacteria, while glycine pretreatment promoted the highest gene transfer rate for Lactococcus lactis. Uptake of green fluorescent bacteria by Caco-2 cells showed that the cell wall-weakening treatment promoted the internalization of the noninvasive bacteria into Caco-2 cells. In conclusion, we have developed a noninvasive system using LAB as a vehicle for vaccine delivery or gene therapy, and tested this system in vitro with Caco-2 cells.

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

    Science.gov (United States)

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

    2016-01-01

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

  3. Influent pathogenic bacteria may go straight into effluent in full scale wastewater treatment plants

    DEFF Research Database (Denmark)

    Kristensen, Jannie Munk; Nierychlo, Marta; Albertsen, Mads

    Incoming microorganisms to wastewater treatment plants (WWTPs) are usually considered to be adsorbed onto the activated sludge flocs, consumed by protozoan or to just die off. Analyses of the effluent generally show a very high degree of reduction of pathogens supporting this assumption. Thus......, it is assumed that the bacteria present in the effluent comprise primarily of those bacteria that thrive/grow in the plants. However, standard techniques for detecting bacteria in the effluent, particularly pathogens, are based on culture-dependent methods, which may give erroneous results by underestimating...... in influent, process tank and effluent in the 14 WWTPs showed that the microbial communities in incoming wastewater were very similar across the plants. The same was observed for communities in the activated sludge in the process tanks. In contrast, the effluent community was in some WWTPs very similar...

  4. The prevalence of foodborne pathogenic bacteria on cutting boards and their ecological correlation with background biota

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    Natsumi Ishida

    2016-05-01

    Full Text Available This study implemented the pyrosequencing technique and real-time quantitative PCR to determine the prevalence of foodborne pathogenic bacteria (FPB and as well as the ecological correlations of background biota and FPB present on restaurant cutting boards (CBs collected in Seri Kembangan, Malaysia. The prevalence of FPB in high background biota (HBB was lower (0.24% compared to that of low background biota (LBB (0.54%. In addition, a multiple linear regression analysis indicated that only HBB had a significant ecological correlation with FPB. Furthermore, statistical analysis revealed that the combinations of Clostridiales, Flavobacteriales, and Lactobacillales orders in HBB had significant negative associations with FPB, suggesting that these bacteria may interact to ensure survivability and impair the growth of pathogenic bacteria.

  5. Some Pathogenic Bacteria of Livestock Origin as a Cause of Foodborne Diseases

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    Anni Kusumaningsih

    2010-09-01

    Full Text Available Food are essentialy required for cell metabolism in human physiologyc. Food should be free from biological, chemical, and physical contamination and also hazardous substances. All of them are able to disrupt physiological homeostatis resulting disorder or diseases. Diseases resulted by those contaminant are called food borne disease. One of the important contaminants is biological contaminant especially pathogenic bacterias. Some pathogenic bacteria such as Salmonella spp., Escherichia coli, Bacillus anthracis, Clostridium spp., Listeria monocytogenes, Campylobacter spp., Vibrio cholerae, Enterobacter sakazakii, Shigella, are able to cause symptomatic diseases. Overall, the general symptoms of the diseases due to pathogenic bacterial infection are gastric pain, nausea, vomit, headache, loss of appetite, fever, and also dehydration.

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

    Science.gov (United States)

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

    2011-10-01

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

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

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    Andreas eHofmann

    2014-05-01

    Full Text Available In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identify possible factors like bacterial species or serovariation, plant species or organic fertilizer types used, influencing the success of plant colonization by human pathogenic bacteria. Spinach and corn salad were chosen as model plants and were inoculated with different concentrations of Salmonella enterica sv. Weltevreden, Listeria monocytogenes sv. 4b and EGD-E sv. 1/2a either directly (axenic system or via agricultural soil amended with spiked organic fertilizers (soil system. In addition to PCR- and culture-based detection methods, fluorescence in situ hybridization (FISH was applied in order to localize bacteria on or in plant tissues. Our results demonstrate that shoots were colonized by the pathogenic bacteria at inoculation doses as low as 4x10CFU/ml in the axenic system or 4x105CFU/g in the soil system. In addition, plant species dependent effects were observed. Spinach was colonized more often and at lower inoculation doses compared to corn salad. Differential colonization sites on roots, depending on the plant species could be detected using FISH-CLSM analysis. Furthermore, the transfer of pathogenic bacteria to plants via organic fertilizers was observed more often and at lower initial inoculation doses when fertilization was performed with inoculated slurry compared to inoculated manure. Finally, it could be shown that by introducing a simple washing step, the bacterial contamination was reduced in most cases or even was removed completely in

  8. Survival of pathogenic bacteria in compost with special reference to Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    GONG Chun-ming; Koichi Inoue; Shunji Inanaga; Takashi Someya

    2005-01-01

    Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157: H7 ( E. Coli O157). We investigated pathogenic bacteria in compost collected from the compost facilities, and evaluated the survival of E. coli K12 and O157 in laboratory experiments. Out of 19 compost product samples, coliform bacteria and salmonella were detected in 7 and 3 samples respectively. The number of coliform bacteria was 1.8 × 102 to 2.5 × 106 CFU/g dw and that of salmonella was 4.2 × 101 to 6.0 × 103 CFU/g dw. Moreover, coliform bacteria, fecal coliform, E. coli and salmonella were detected during composting at 54℃ to 67℃. The results indicated that moisture content was a very important factor to the heat sensitivity of pathogenic bacteria in compost, E. coli in compost of high moisture content was more sensitive than that in compost of low moisture content, cells harvested in logarithmic phase was more sensitive than these in stationary phase, and E. coli K12 was more sensitive than E. coli O157. Based on the D values, the lethal time of E. coli K12 and O157 from 108 to 100 CFU/g dw were 16.3 and 28.8 min, respectively, at 60℃ in compost with 40% moisture content. However, some E. coli cells survived in composting process at 54℃ to 67℃. Water potential (low moisture content) and physiological aspects of bacteria (stationary phase) could explain only in part of the prolonged survival of E. coli in compost, and there should be some other factors that are conducive to bacterial survival in compost.

  9. 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.

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

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    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

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

    Science.gov (United States)

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

    2013-10-01

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

  12. EFFICACY OF EXTRACTS OF SIX MEDICINAL PLANTS OF INDIA AGAINST SOME PATHOGENIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Indranil Bhattacharjee

    2013-02-01

    Full Text Available The sensitivity of the pathogenic multi-drug resistant bacteria (Aeromonas hydrophila, Bacillus licheniformis, Bacillus mycoides, Bacillus niacini, Bacillus subtilis, Escherichia coli, Geobacillus thermodenitrificans, Klebsiella pneumoniae, Paenibacillus koreensis, Paenibacillus larvae larvae, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas flourescens, Pseudomonas putida and Staphylocccus aureus was tested against aqueous, acetone and ethanol extracts of mature leaves of Mimosa pudica Linn. (Mimosaceae and Moringa oleifera Lam. (Moringaceae, stems of Michelia champaca Linn. (Magnoliaceae and Musa paradisiaca Linn.(Musaceae, roots of Momordica charantia Linn. (Cucurbitaceae and Murraya koenigii Linn. (Rutaceae by agar well diffusion method. Gatifloxacin was the most effective antibiotic against all the reference bacteria. Though all the extracts were found effective, the ethanol extract showed maximum inhibition against the test microorganisms followed by acetone and aqueous extract. Bacillus niacini is the most resistant bacteria and Klebsiella pneumoniae is the most sensitive bacteria against all the extracts used. MIC values of each bacterium were also determined

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

    Science.gov (United States)

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

    2015-01-01

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

  14. Efficient removal of pathogenic bacteria and viruses by multifunctional amine-modified magnetic nanoparticles.

    Science.gov (United States)

    Zhan, Sihui; Yang, Yang; Shen, Zhiqiang; Shan, Junjun; Li, Yi; Yang, Shanshan; Zhu, Dandan

    2014-06-15

    A novel amine-functionalized magnetic Fe3O4-SiO2-NH2 nanoparticle was prepared by layer-by-layer method and used for rapid removal of both pathogenic bacteria and viruses from water. The nanoparticles were characterized by TEM, EDS, XRD, XPS, FT-IR, BET surface analysis, magnetic property tests and zeta-potential measurements, respectively, which demonstrated its well-defined core-shell structures and strong magnetic responsivity. Pathogenic bacteria and viruses are often needed to be removed conveniently because of a lot of co-existing conditions. The amine-modified nanoparticles we prepared were attractive for capturing a wide range of pathogens including not only bacteriophage f2 and virus (Poliovirus-1), but also various bacteria such as S. aureus, E. coli O157:H7, P. aeruginosa, Salmonella, and B. subtilis. Using as-prepared amine-functionalized MNPs as absorbent, the nonspecific removal efficiency of E. coli O157:H7 or virus was more than 97.39%, while it is only 29.8% with Fe3O4-SiO2 particles. From joint removal test of bacteria and virus, there are over 95.03% harmful E. coli O157:H7 that can be removed from mixed solution with polyclonal anti-E. coli O157:H7 antibody modified nanoparticles. Moreover, the synergy effective mechanism has also been suggested.

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

    Directory of Open Access Journals (Sweden)

    Konstantinos Papadimitriou

    2013-02-01

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

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

    Science.gov (United States)

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

    2011-06-01

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

  17. Identification and Pathogenicity of Phytopathogenic Bacteria Associated with Soft Rot Disease of Girasole Tuber

    Directory of Open Access Journals (Sweden)

    Mamdoh Ewis ISMAIL

    2012-02-01

    Full Text Available During 2010-2011 growing seasons six bacterial isolates were separated from naturally infected girasole plants tubers (Helianthus tuberosus L. cv. Balady, showing soft rot, collected from experimental Farm of the Faculty of Agriculture, in El-Minia University, Egypt. Pathogenicity tests showed various virulence for the bacteria isolated from girasole tubers, found pathogenic. These organisms were characterized as rod-shaped, Gram negative, ?-methyl-d-glucoside medium, reducing substances from sucrose, phos, phatase activity and deep cavities on pectate medium. Otherwise, diagnostic tests suggested that the pathogen was Erwinia carotovora ssp. carotovora. The isolated bacteria caused soft rot of wounded tubers when inoculated into tissues. The bacterial isolates were compared for their degree of pathogenicity as well as for differences in specific symptoms, induced in different hosts. The tested isolates could infect several host ranges, such as fruits of apricot, apple, olive, lemon, squash, eggplant and potato tubers, bulbs and garlic and onion cloves, roots radish, carrot, sweet potato and rape. On the other hand, no symptoms were exhibited on pods of bean and cowpea, faba bean, fruits of pepper and tomato. The extracts of experimentally diseased girasole tubers were active in pectinase and also in caboxymethyl cellulose at pH 6 compared to enzyme activities in healthy tissues. Also, the isolated bacteria increased the total and reducing sugars in infected tissues.

  18. Identification and Pathogenicity of Phytopathogenic Bacteria Associated with Soft Rot Disease of Girasole Tuber

    Directory of Open Access Journals (Sweden)

    Mamdoh Ewis ISMAIL

    2012-02-01

    Full Text Available During 2010-2011 growing seasons six bacterial isolates were separated from naturally infected girasole plants tubers (Helianthus tuberosus L. cv. �Balady�, showing soft rot, collected from experimental Farm of the Faculty of Agriculture, in El-Minia University, Egypt. Pathogenicity tests showed various virulence for the bacteria isolated from girasole tubers, found pathogenic. These organisms were characterized as rod-shaped, Gram negative, ?-methyl-d-glucoside medium, reducing substances from sucrose, phos, phatase activity and deep cavities on pectate medium. Otherwise, diagnostic tests suggested that the pathogen was Erwinia carotovora ssp. carotovora. The isolated bacteria caused soft rot of wounded tubers when inoculated into tissues. The bacterial isolates were compared for their degree of pathogenicity as well as for differences in specific symptoms, induced in different hosts. The tested isolates could infect several host ranges, such as fruits of apricot, apple, olive, lemon, squash, eggplant and potato tubers, bulbs and garlic and onion cloves, roots radish, carrot, sweet potato and rape. On the other hand, no symptoms were exhibited on pods of bean and cowpea, faba bean, fruits of pepper and tomato. The extracts of experimentally diseased girasole tubers were active in pectinase and also in caboxymethyl cellulose at pH 6 compared to enzyme activities in healthy tissues. Also, the isolated bacteria increased the total and reducing sugars in infected tissues.

  19. Fluorescence microscopy methods for determining the viability of bacteria in association with mammalian cells.

    Science.gov (United States)

    Johnson, M Brittany; Criss, Alison K

    2013-09-05

    Central to the field of bacterial pathogenesis is the ability to define if and how microbes survive after exposure to eukaryotic cells. Current protocols to address these questions include colony count assays, gentamicin protection assays, and electron microscopy. Colony count and gentamicin protection assays only assess the viability of the entire bacterial population and are unable to determine individual bacterial viability. Electron microscopy can be used to determine the viability of individual bacteria and provide information regarding their localization in host cells. However, bacteria often display a range of electron densities, making assessment of viability difficult. This article outlines protocols for the use of fluorescent dyes that reveal the viability of individual bacteria inside and associated with host cells. These assays were developed originally to assess survival of Neisseria gonorrhoeae in primary human neutrophils, but should be applicable to any bacterium-host cell interaction. These protocols combine membrane-permeable fluorescent dyes (SYTO9 and 4',6-diamidino-2-phenylindole [DAPI]), which stain all bacteria, with membrane-impermeable fluorescent dyes (propidium iodide and SYTOX Green), which are only accessible to nonviable bacteria. Prior to eukaryotic cell permeabilization, an antibody or fluorescent reagent is added to identify extracellular bacteria. Thus these assays discriminate the viability of bacteria adherent to and inside eukaryotic cells. A protocol is also provided for using the viability dyes in combination with fluorescent antibodies to eukaryotic cell markers, in order to determine the subcellular localization of individual bacteria. The bacterial viability dyes discussed in this article are a sensitive complement and/or alternative to traditional microbiology techniques to evaluate the viability of individual bacteria and provide information regarding where bacteria survive in host cells.

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

    Directory of Open Access Journals (Sweden)

    Yixian Wang

    2012-03-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

  3. Role of periodontal pathogenic bacteria in RANKL-mediated bone destruction in periodontal disease

    Science.gov (United States)

    Kajiya, Mikihito; Giro, Gabriela; Taubman, Martin A.; Han, Xiaozhe; Mayer, Marcia P.A.; Kawai, Toshihisa

    2010-01-01

    Accumulated lines of evidence suggest that hyperimmune responses to periodontal bacteria result in the destruction of periodontal connective tissue and alveolar bone. The etiological roles of periodontal bacteria in the onset and progression of periodontal disease (PD) are well documented. However, the mechanism underlying the engagement of periodontal bacteria in RANKL-mediated alveolar bone resorption remains unclear. Therefore, this review article addresses three critical subjects. First, we discuss earlier studies of immune intervention, ultimately leading to the identification of bacteria-reactive lymphocytes as the cellular source of osteoclast-induction factor lymphokine (now called RANKL) in the context of periodontal bone resorption. Next, we consider (1) the effects of periodontal bacteria on RANKL production from a variety of adaptive immune effector cells, as well as fibroblasts, in inflamed periodontal tissue and (2) the bifunctional roles (upregulation vs. downregulation) of LPS produced from periodontal bacteria in a RANKL-induced osteoclast-signal pathway. Future studies in these two areas could lead to new therapeutic approaches for the management of PD by down-modulating RANKL production and/or RANKL-mediated osteoclastogenesis in the context of host immune responses against periodontal pathogenic bacteria. PMID:21523224

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

    Science.gov (United States)

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

    2013-11-15

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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Álvaro D. Ortega

    2014-11-01

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

  7. The mammalian complement system as an epitome of host-pathogen genetic conflicts.

    Science.gov (United States)

    Cagliani, Rachele; Forni, Diego; Filippi, Giulia; Mozzi, Alessandra; De Gioia, Luca; Pontremoli, Chiara; Pozzoli, Uberto; Bresolin, Nereo; Clerici, Mario; Sironi, Manuela

    2016-03-01

    The complement system is an innate immunity effector mechanism; its action is antagonized by a wide array of pathogens and complement evasion determines the virulence of several infections. We investigated the evolutionary history of the complement system and of bacterial-encoded complement-interacting proteins. Complement components targeted by several pathogens evolved under strong selective pressure in primates, with selection acting on residues at the contact interface with microbial/viral proteins. Positively selected sites in CFH and C4BPA account for the human specificity of gonococcal infection. Bacterial interactors, evolved adaptively as well, with selected sites located at interaction surfaces with primate complement proteins. These results epitomize the expectation under a genetic conflict scenario whereby the host's and the pathogen's genes evolve within binding avoidance-binding seeking dynamics. In silico mutagenesis and protein-protein docking analyses supported this by showing that positively selected sites, both in the host's and in the pathogen's interacting partner, modulate binding.

  8. Host-Recognition of Pathogens and Commensals in the Mammalian Intestine

    NARCIS (Netherlands)

    Rossi, O.; Baarlen, van P.; Wells, J.

    2011-01-01

    To peacefully coexist with the microbial inhabitants of the intestine, mammals have evolved elaborate and interconnected regulatory mechanisms to maintain immune homeostasis in the face of potential infection and tissue damage by pathogenic microorganisms. Physical barriers, antimicrobial factors an

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

    Science.gov (United States)

    Tong, Zhongchun; Ni, Longxing; Ling, Junqi

    2014-10-01

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

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

    Science.gov (United States)

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

    2015-12-01

    The development of a versatile approach for the rapid and sensitive detection of relevant pathogenic bacteria and autonomous signaling of the detection events in reporter hydrogel film coatings is reported. Exploiting chitosan hydrogel films equipped with chromogenic or fluorogenic reporter moieties, the presence of the Gram-negative bacterium Pseudomonas aeruginosa and the Gram-positive bacterium Staphylococcus aureus is sensed within 1 h by detecting the characteristic enzymes α-glucosidase and elastase with limits of detection (LOD) hydrogels comprise an interesting platform for the rapid detection of bacteria.

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

    DEFF Research Database (Denmark)

    Breum Andersen, Sandra; Marvig, Rasmus Lykke; Molin, Søren

    2015-01-01

    social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find that Pseudomonas aeruginosa bacteria, causing lung......Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly...... in the host environment. More generally, we provide an example of how sequence analysis can be used to generate testable hypotheses about selection driving long-term phenotypic changes of pathogenic bacteria in situ....

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

    Directory of Open Access Journals (Sweden)

    Daniela Jacob

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

  13. Two-component signal transduction as potential drug targets in pathogenic bacteria.

    Science.gov (United States)

    Gotoh, Yasuhiro; Eguchi, Yoko; Watanabe, Takafumi; Okamoto, Sho; Doi, Akihiro; Utsumi, Ryutaro

    2010-04-01

    Gene clusters contributing to processes such as cell growth and pathogenicity are often controlled by two-component signal transduction systems (TCSs). Specific inhibitors against TCS systems work differently from conventional antibiotics, and developing them into new drugs that are effective against various drug-resistant bacteria may be possible. Furthermore, inhibitors of TCSs that control virulence factors may reduce virulence without killing the pathogenic bacteria. Previous TCS inhibitors targeting the kinase domain of the histidine kinase sensor suffered from poor selectivity. Recent TCS inhibitors, however, target the sensory domains of the sensors blocking the quorum sensing system, or target the essential response regulator. These new targets are introduced, together with several specific TCSs that have the potential to serve as effective drug targets. Copyright 2010 Elsevier Ltd. All rights reserved.

  14. Antimicrobial resistance among pathogenic bacteria from mink (Neovison vison) in Denmark

    DEFF Research Database (Denmark)

    Nikolaisen, Nanett Kvist; Lassen, Desireé Corvera Kløve; Chriél, Mariann

    2017-01-01

    of antimicrobial resistance among pathogenic bacteria isolated from Danish mink during the period 2014-2016. The aim of this investigation was to provide data on antimicrobial resistance and consumption, to serve as background knowledge for new veterinary guidelines for prudent and optimal antimicrobial usage...... of resistance to tetracycline and erythromycin. The antimicrobial consumption increased significantly during 2007-2012, and fluctuated at a high level during 2012-2016, except for a temporary drop in 2013-2014. The majority of the prescribed antimicrobials were aminopenicillins followed by tetracyclines...... and macrolides. Conclusions: The study showed that antimicrobial resistance was common in most pathogenic bacteria from mink, in particular hemolytic E. coli. There is a need of guidelines for prudent use of antimicrobials for mink....

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

    DEFF Research Database (Denmark)

    Bruhn, Jesper Bartholin; Dalsgaard, Inger; Nielsen, K.F.

    2005-01-01

    and plant-pathogenic bacteria. A total of 59 strains, representing 9 different fish pathogenic species, were tested against 2 AHL monitor bacteria (Agrobacterium tumefaciens NT1 [pZLR4] and Chromobacterium violaceum CV026) in a well diffusion assay and by thin-layer chromatography (TLC). Representative...... salmonicida and Vibrio splendidus were also positive. Aeromonas species produced N-butanoyl homoserine lactone (BHL) and N-hexanoyl homoserine lactone (HHL) and 1 additional product, whereas N-3-oxo-hexanoyl homoserine lactone (OHHL) and HHL were detected in Vibrio salmonicida. N-3-oxo-octanoyl homoserine...... lactone (OOHL) and N-3-octanoyl homoserine lactone (OHL) were detected in Y. ruckeii. AHLs were not detected from strains of Photobacterium damselae, Flavobacterium psychrophilum or Moritella viscosa. AHLs were extracted from fish infected with Y. ruckeri but not from fish infected with A. salmonicida...

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

    Science.gov (United States)

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

    2013-02-01

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

  17. Transfer of plasmid-mediated resistance to tetracycline in pathogenic bacteria from fish and aquaculture environments.

    Science.gov (United States)

    Guglielmetti, Elena; Korhonen, Jenni M; Heikkinen, Jouni; Morelli, Lorenzo; von Wright, Atte

    2009-04-01

    The transferability of a large plasmid that harbors a tetracycline resistance gene tet(S), to fish and human pathogens was assessed using electrotransformation and conjugation. The plasmid, originally isolated from fish intestinal Lactococcus lactis ssp. lactis KYA-7, has potent antagonistic activity against the selected recipients (Lactococcus garvieae and Listeria monocytogenes), preventing conjugation. Therefore the tetracycline resistance determinant was transferred via electroporation to L. garvieae. A transformant clone was used as the donor in conjugation experiments with three different L. monocytogenes strains. To our knowledge, this is the first study showing the transfer of an antibiotic resistance plasmid from fish-associated lactic bacteria to L. monocytogenes, even if the donor L. garvieae was not the original host of the tetracycline resistance but experimentally created by electroporation. These results demonstrate that the antibiotic resistance genes in the fish intestinal bacteria have the potential to spread both to fish and human pathogens, posing a risk to aquaculture and consumer safety.

  18. Adaptation of mammalian host-pathogen interactions in a changing arctic environment

    Science.gov (United States)

    2011-01-01

    Many arctic mammals are adapted to live year-round in extreme environments with low winter temperatures and great seasonal variations in key variables (e.g. sunlight, food, temperature, moisture). The interaction between hosts and pathogens in high northern latitudes is not very well understood with respect to intra-annual cycles (seasons). The annual cycles of interacting pathogen and host biology is regulated in part by highly synchronized temperature and photoperiod changes during seasonal transitions (e.g., freezeup and breakup). With a warming climate, only one of these key biological cues will undergo drastic changes, while the other will remain fixed. This uncoupling can theoretically have drastic consequences on host-pathogen interactions. These poorly understood cues together with a changing climate by itself will challenge host populations that are adapted to pathogens under the historic and current climate regime. We will review adaptations of both host and pathogens to the extreme conditions at high latitudes and explore some potential consequences of rapid changes in the Arctic. PMID:21392401

  19. Adaptation of mammalian host-pathogen interactions in a changing arctic environment.

    Science.gov (United States)

    Hueffer, Karsten; O'Hara, Todd M; Follmann, Erich H

    2011-03-11

    Many arctic mammals are adapted to live year-round in extreme environments with low winter temperatures and great seasonal variations in key variables (e.g. sunlight, food, temperature, moisture). The interaction between hosts and pathogens in high northern latitudes is not very well understood with respect to intra-annual cycles (seasons). The annual cycles of interacting pathogen and host biology is regulated in part by highly synchronized temperature and photoperiod changes during seasonal transitions (e.g., freezeup and breakup). With a warming climate, only one of these key biological cues will undergo drastic changes, while the other will remain fixed. This uncoupling can theoretically have drastic consequences on host-pathogen interactions. These poorly understood cues together with a changing climate by itself will challenge host populations that are adapted to pathogens under the historic and current climate regime. We will review adaptations of both host and pathogens to the extreme conditions at high latitudes and explore some potential consequences of rapid changes in the Arctic.

  20. Adaptation of mammalian host-pathogen interactions in a changing arctic environment

    Directory of Open Access Journals (Sweden)

    O'Hara Todd M

    2011-03-01

    Full Text Available Abstract Many arctic mammals are adapted to live year-round in extreme environments with low winter temperatures and great seasonal variations in key variables (e.g. sunlight, food, temperature, moisture. The interaction between hosts and pathogens in high northern latitudes is not very well understood with respect to intra-annual cycles (seasons. The annual cycles of interacting pathogen and host biology is regulated in part by highly synchronized temperature and photoperiod changes during seasonal transitions (e.g., freezeup and breakup. With a warming climate, only one of these key biological cues will undergo drastic changes, while the other will remain fixed. This uncoupling can theoretically have drastic consequences on host-pathogen interactions. These poorly understood cues together with a changing climate by itself will challenge host populations that are adapted to pathogens under the historic and current climate regime. We will review adaptations of both host and pathogens to the extreme conditions at high latitudes and explore some potential consequences of rapid changes in the Arctic.

  1. Sugar fatty acid esters inhibit biofilm formation by food-borne pathogenic bacteria

    OpenAIRE

    Furukawa, Soichi; Akiyoshi, Yuko; O’Toole, George A; Ogihara, Hirokazu; Morinaga, Yasushi

    2010-01-01

    Effects of food additives on biofilm formation by food-borne pathogenic bacteria were investigated. Thirty-three potential food additives and 3 related compounds were added to the culture medium at concentrations from 0.001 to 0.1% (w/w), followed by inoculation and cultivation of five biofilm-forming bacterial strains for the evaluation of biofilm formation. Among the tested food additives, 21 showed inhibitory effects of biofilm formation by Staphylococcus aureus and Escherichia coli, and i...

  2. 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...

  3. COAGGREGATION AND COAGGREGATION INHIBITION BETWEEN PERIO-PATHOGENIC AND CARIOGENIC BACTERIA

    Institute of Scientific and Technical Information of China (English)

    FU Rao; LI De-yi

    2005-01-01

    Objective To screen the coaggregating pairs between perio-pathogenic and cariogenic bacteria and to investigate the susceptibility of these coaggregations to inhibitors. Methods 4 strains of perio-pathogenic bacteria, Fusobacterium nuleatum (Fn) ATCC 10953, Actinobacilllus actinomycetem comitans (Aa) Y4, Porphyromonas gingivalis (Pg) ATCC 33277,Prevotella intermedia (Pi) ATCC 25261 and 4 strains of cariogenic bacteria, Streptococcus mutans (Sm) Ingbritt, Streptococcus sanguis (Ss) 34, Actinomyces viscosus (Av) 19246 and Lactobacillus acidophilus (La) ATCC 4356 were used to determine the coaggregating degrees of various combinations of the above bacteria by a visual assay and a turbidimetric assay. Then more than +2(or 20%) coaggregation degrees' pairs were used to investigate the inhibitory effect of lactose and arginine and to identify the minimum of their coaggregation-inhibitory concentration. Results The coaggregation degrees of Fn-Av, Pg-Av, Fn-Sm, Fn-Ss, Fn-La and Pg-Ss pairs were higher than +2(20%). 3.0 ~ 6.0mmol/L of arginine were considerably effective to the above pairs except Fn-Av pair and the disaggregation degrees were 49% ~ 92%. The maximum of their disaggregation degree to Fn-Av pair was just 18%. 120 ~ 300mmol/L of lactose were significantly effective to Pg-Ss pair, the disaggregation degrees were 57% ~ 91%. They partially inhibited Pg-Av pair and were almost ineffective to Fn-G + pairs. Conclusion The coaggregations between perio-pathogenic and cariogenic bacteria are highly specific. Most of them are relatively sensitive to arginine.

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

    Science.gov (United States)

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

    2010-11-01

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

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

    Science.gov (United States)

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

    2015-05-01

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

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

    Science.gov (United States)

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

    2016-06-01

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

  7. Non-biting flying insects as carriers of pathogenic bacteria in a Brazilian hospital

    Directory of Open Access Journals (Sweden)

    Henrique Borges Kappel

    2013-04-01

    Full Text Available Introduction Insects have been described as mechanical vectors of nosocomial infections. Methods Non-biting flying insects were collected inside a pediatric ward and neonatal-intensive care unit (ICU of a Brazilian tertiary hospital. Results Most (86.4% of them were found to carry one or more species of bacteria on their external surfaces. The bacteria isolated were Gram-positive bacilli (68.2% or cocci (40.9%, and Gram-negative bacilli (18.2%. Conclusions Insects collected inside a hospital were carrying pathogenic bacteria; therefore, one must consider the possibility they may act as mechanical vectors of infections, in especially for debilitated or immune-compromised patients in the hospital environments where the insects were collected.

  8. Detection and identification of intestinal pathogenic bacteria by hybridization to oligonucleotide microarrays

    Institute of Scientific and Technical Information of China (English)

    Lian-Qun Jin; Jun-Wen Li; Sheng-Qi Wang; Fu-Huan Chao; Xin-Wei Wang; Zheng-Quan Yuan

    2005-01-01

    AIM: To detect the common intestinal pathogenic bacteria quickly and accurately.METHODS: A rapid (<3 h) experimental procedure was set up based upon the gene chip technology. Target genes were amplified and hybridized by oligonucleotide microarrays.RESULTS: One hundred and seventy strains of bacteria in pure culture belonging to 11 genera were successfully discriminated under comparatively same conditions, and a series of specific hybridization maps corresponding to each kind of bacteria were obtained. When this method was applied to 26 divided cultures, 25 (96.2%) were identified.CONCLUSION: Salmonella sp., Escherichia coli, Shigella sp., Listeria monocytogenes, Vibrio parahaemolyticus,Staphylococcus aureus, Proteus sp., Bacillus cereus,Vibrio cholerae, Enterococcus faecalis, Yersinia enterocolitica, and Campylobacter jejuni can be detected and identified by our microarrays. The accuracy, range,and discrimination power of this assay can be continually improved by adding further oligonucleotides to the arrays without any significant increase of complexity or cost.

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

    Science.gov (United States)

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

    2016-10-01

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

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

    Science.gov (United States)

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

    2008-10-01

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

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

    Science.gov (United States)

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

    2012-10-01

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

  12. Antibacterial Effect of Myrtus Communis Hydro-Alcoholic Extract on Pathogenic Bacteria

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    Ali Taheri

    2013-06-01

    Full Text Available Background: Today, due to the changes in the form of the resistance of pathogenic bacteria, discovering new antimicrobial drugs is under study. So, the aim of this study is to evaluate the antimicrobial properties of the extract of the myrtle herb on some of pathogenic bacteria. Materials and Methods: Hydroalcoholic extract of the leaves of myrtle herb was evaluated at 4 concentrations including 10-80 mg/ml on four strains of pathogenic bacteria using penetrative dissemination method together with the measuring diameter of the growth inhibition zone; then the results were compared to four conventional antibiotics. The minimum inhibitory and bactericidal concentrations were studied using macro dilution method. Results: Treatment by the concentration of 80 mg/ml extract of this herb showed the greatest effect on the bacterium Staphylococcus aureus and Vibrio cholera serotype Ogawa which had a significant difference with all other treatments and standard antibiotics (p> 0.05. The extract showed no effect on the bacterium Pseudomonas aeruginosa and just concentration of 80 mg/ml showed a little effect on E. coli and other antibiotics had no significant effect except tetracycline which has little effect on this strain. Minimum inhibitory concentration was 0.2 mg/ml for bacterium Staphylococcus aureus (S. aureus and the maximum for E.coli by 8 mg/ml.Conclusion: This study showed that under study bacteria were more resistant to the antibiotics and the extract of Myrtus communis leaves showed greatest antibacterial effect against S. aureus and V. cholerae cerotype Ogawa.

  13. Outer-inner membrane vesicles naturally secreted by gram-negative pathogenic bacteria.

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    Carla Pérez-Cruz

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

  14. Outer-inner membrane vesicles naturally secreted by gram-negative pathogenic bacteria.

    Science.gov (United States)

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

    2015-01-01

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

  15. SERS based immuno-microwell arrays for multiplexed detection of foodborne pathogenic bacteria

    Science.gov (United States)

    Sun, Jian; Hankus, Mikella E.; Cullum, Brian M.

    2009-05-01

    A novel surface enhanced Raman scattering (SERS)-based immuno-microwell array has been developed for multiplexed detection of foodborne pathogenic bacteria. The immuno-microwell array was prepared by immobilizing the optical addressable immunomagnetic beads (IMB) into the microwell array on one end of a fiber optic bundle. The IMBs, magnetic beads coated with specific antibody to specific bacteria, were used for immunomagnetic separation (IMS) of corresponding bacteria. The magnetic separation by the homemade magnetic separation system was evaluated in terms of the influences of several important parameters including the beads concentration, the sample volume and the separation time. IMS separation efficiency of the model bacteria E.coli O157:H7 was 63% in 3 minutes. The microwell array was fabricated on hydrofluoric acid etched end of a fiber optic bundle containing 30,000 fiber elements. After being coated with silver, the microwell array was used as a uniform SERS substrate with the relative standard deviation of the SERS enhancement across the microwell array < 2% and the enhancement factor as high as 2.18 x 107. The antibody modified microwell array was prepared for bacteria immobilization into the microwell array, which was characterized by a sandwich immunoassay. To demonstrate the potential of multiplexed SERS detection with the immuno-microwell array, the SERS spectra of different Raman dye labeled magnetic beads as well as mixtures were measured on the mircrowell array. In bead mixture, different beads were identified by the characteristic SERS bands of the corresponding Raman label.

  16. Antimicrobial and efflux pump inhibitory activity of caffeoylquinic acids from Artemisia absinthium against gram-positive pathogenic bacteria.

    NARCIS (Netherlands)

    Fiamegos, Y.C.; Kastritis, P.L.; Exarchou, V.; Han, H.; Bonvin, A.M.; Vervoort, J.J.M.; Lewis, K.; Hamblin, M.R.; Tegos, G.P.

    2011-01-01

    Background Traditional antibiotics are increasingly suffering from the emergence of multidrug resistance amongst pathogenic bacteria leading to a range of novel approaches to control microbial infections being investigated as potential alternative treatments. One plausible antimicrobial alternative

  17. Antimicrobial and efflux pump inhibitory activity of caffeoylquinic acids from Artemisia absinthium against Gram-positive pathogenic bacteria

    NARCIS (Netherlands)

    Fiamegos, Y.C.; Kastritis, P.; Exarchou, V.; Han, H.; Bonvin, A.M.J.J.; Vervoort, J.; Lewis, K.; Hamblin, M.R.; Tegos, G.P.

    2011-01-01

    Background: Traditional antibiotics are increasingly suffering from the emergence of multidrug resistance amongst pathogenic bacteria leading to a range of novel approaches to control microbial infections being investigated as potential alternative treatments. One plausible antimicrobial alternative

  18. Biotherapy for and protection against gastrointestinal pathogenic infections via action of probiotic bacteria

    Directory of Open Access Journals (Sweden)

    Mongkol Thirabunyanon

    2011-03-01

    Full Text Available The microbiota in the human intestine play an important function in human health and disease. Gastrointestinal infections by foodborne pathogens are a main cause of morbidity and mortality worldwide. Such infections can be caused by contaminated foods or other sources which come in contact with human intestinal epithelial cells. In recent years, probiotics have been recommended as alternative biotherapeutic agents against intestinal pathogenic infections. Two genera of probiotics, Lactobacillus and Bifidobacterium, are commercially valuable applications, several forms of which are available as capsules or in functional food products such as yogurt, fermented juices and sausages. Probiotics protect against gastrointestinal pathogenic infection via several mechanisms. These include production of antimicrobial substances, competition for nutrient substrates, competitive exclusion, enhancement of intestinal barrier function, and immunomodulation. Probiotic bacteria have been documented as being effective in biotherapeutic applications against gastrointestinal pathogens, e.g. Helicobacter pylori, Salmonella, Escherichia coli, Listeria monocytogenes, and rotaviruses. This alternative therapeutic application of probiotics to protect against gastrointestinal pathogenic infections may be of great importance for future medicinal use.

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

    Science.gov (United States)

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

    2008-01-01

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

  20. Investigating the Effectiveness of Centaureacyanus Extracts on Planktonic Growth and Biofilm Structures of Six Pathogenic Bacteria

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    Z Mohsenipour

    2014-10-01

    Full Text Available Introduction: Nowadays, the treatments of infectious disease are regarded difficult due to increasing antibiotic resistance among pathogenic bacteria, which the reason may be placing of microorganisms in a structure named biofilm. Biofilms are complex structures consisting of surface-attached bacteria. Therefore, it is essential to find new compounds in order to remove and inhibit biofilms. This study aimed to examine the antibacterial activities of alcoholic extracts of Centaurea cyanus on the biofilm structures and planktonic form of six pathogen bacteria(Staphylococcusaureus, Bacilluscereus, Streptococcuspneumoniae, Pseudomonasaeruginosa, Escherichiacoli and Klebsiellapneumonia. Methods: Antimicrobial activities of the alcoholic plant extracts against the planktonic form of bacteria were assessed via using the disc diffusion method. MIC and MBC values were determined by a macrobroth dilution technique and anti-biofilm effects were scrutinized by microtiter plate method. Results: The results of this study confirmed high ability of C.cyanus extracts against the biofilm of the tested bacteria as well as their free-living forms. To inhibit bacterial growth, ethanolic extracts proved to be more effective than methanolic extracts. Anti-biofilm effects of plant extracts were associated with the solvent type and extract concentration. C.cyanus extracts were reported to be most efficient to inhibit biofilm formation of E. coli (84/26% and S. pneumoniae(83/14%. The greatest eradication of biofilm structures were observed on S. pneumonia biofilm (75.66%, and the highest decrease in metabolic activity was reported in S.aureus biofilms (71/85%. Conclusion: In this study the high capacity of C. cyanus extracts to encounter with whit biofilm was emphasized. Moreover, it was demonstrated that these extracts possess an appropriate potential to become active principles of new drugs.

  1. Evaluation of antibiotic resistance among isolated pathogenic bacteria from shrimp hatcheries in Bushehr province

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    Azam Moghimi

    2014-01-01

    Full Text Available Abstract Background: Rapid development of shrimp aquaculture has resulted in widespread use of antibiotics for preventing and curing diseases. In aquaculture, particularly shrimp hatcheries antibiotics are routinely used at therapeutic levels to treat disease and at sub-therapeutic levels as prophylactic agents to increase feed efficiency. Antibiotic residues in the environment are likely to lead to the development and maintenance of antibiotic resistance in microbial populations. The aim of this study was determine of antibiotic resistance to two shrimp pathogens Vibrio harveyi, V.alginolyticus, that they are agents of mortality in shrimp hatcheries. Material and Methods: After isolation and detection(by biochemical tests of two species of bacterial pathogens from three hatcheries of Bushehr province, bacterial strains were tested for sensitivity to antibiotics including erythromycin, streptomycin, oxytetracyclin, and trimetoprim by disk diffusion method. Results: Results showed that all isolated bacteria Vibrio harveyi from three hatcheries were sensitive to oxytetracyclin and trimetoprim, but to streptomycin were resistant, and to erythromycin in hatcheries A, B, C was intermediate, resistance, sensitive respectively. Bacteria Vibrio alginolyticus isolated from three hatcheries were resistant to streptomycin. But they isolated from a hatchery to the other antibiotics erythromycin, oxytetracyclin and trimetoprim were resistant, intermediate and intermediate, respectively. Also they isolated from B hatchery were resistant, sensitive and sensitive to erythromycin, oxytetracyclin and trimetoprim, respectively And from C hatchery were intermediate, sensitive and sensitive to antibiotics, respectively. Conclusion: Isolated bacteria showed the most resistance to streptomycin and erythromycin respectively. These antibiotics is used frequently in medicine and veterinary, with entrance of human and animal's bacteria resistance via waste and fluid water

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

    Science.gov (United States)

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

    2016-05-01

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

  3. The application of loop-mediated isothermal amplification for detection of common pathogenic bacteria in lower respiratory tract infections

    Institute of Scientific and Technical Information of China (English)

    陈愉生

    2014-01-01

    Objective To investigate the spectrum of common pathogenic bacteria of low respiratory tract infection by loop-mediated isothermal amplification(LAMP)of nucleic acid test and to prove the clinical significance of this method.Methods A total of 289 qualified sputum samples from patients with lower respiratory tract infections in Fujian Province were detected by LAMP technique,and then the distribution of pathogenic bacteria was analyzed.The positive cases(the patients whose specific3

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

    Science.gov (United States)

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

    2013-09-27

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

  5. Isolation, amplification and characterization of foodborne pathogen disease bacteria gene for rapid kit test development

    Science.gov (United States)

    Nurjayadi, M.; Santoso, I.; Kartika, I. R.; Kurniadewi, F.; Saamia, V.; Sofihan, W.; Nurkhasanah, D.

    2017-07-01

    There is a lot of public concern over food safety. Food-safety cases recently, including many food poisoning cases in both the developed and developing countries, considered to be the national security threats which involved police investigation. Quick and accurate detection methods are needed to handle the food poisoning cases with a big number of sufferers at the same time. Therefore, the research is aimed to develop a specific, sensitive, and rapid result molecular detection tool for foodborne pathogen bacteria. We, thus, propose genomic level approach with Polymerase Chain Reaction. The research has successfully produced a specific primer to perform amplification to fim-C S. typhi, E. coli, and pef Salmonella typhimurium genes. The electrophoresis result shows that amplification products are 95 base pairs, 121 base pairs, and 139 base pairs; and all three genes are in accordance with the size of the in silico to third genes bacteria. In conclusion, the research has been successfully designed a specific detection tool to three foodborne pathogen bacteria genes. Further stages test and the uses of Real-time PCR in the detection are still in the trial process for better detection method.

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

    Science.gov (United States)

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

    2014-11-01

    The implementation of beneficial microorganisms for plant protection has a long history. Many rhizobia bacteria are able to influence the immune system of host plants by inducing resistance towards pathogenic microorganisms. In this report, we present a translational approach in which we demonstrate the resistance-inducing effect of Ensifer meliloti (Sinorhizobium meliloti) on crop plants that have a significant impact on the worldwide economy and on human nutrition. Ensifer meliloti is usually associated with root nodulation in legumes and nitrogen fixation. Here, we suggest that the ability of S. meliloti to induce resistance depends on the production of the quorum-sensing molecule, oxo-C14-HSL. The capacity to enhanced resistance provides a possibility to the use these beneficial bacteria in agriculture. Using the Arabidopsis-Salmonella model, we also demonstrate that the application of N-acyl-homoserine lactones-producing bacteria could be a successful strategy to prevent plant-originated infections with human pathogens. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  7. Inhibition Effect of Lactic Acid Bacteria against Food Born Pathogen, Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Rouha Kasra-Kermanshahi

    2015-09-01

    Full Text Available Disease caused by consuming microbial contaminated food has increased significantly in recent years due to changes in the livelihoods and eating habits of the human populations. Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica are three of the most important foodborne bacterial pathogens and can lead to foodborne diseases. Increased use of antibiotics, has led to development of bacterial resistance to antibiotics. Therefore, there is growing interest in the development of new types of effective and nontoxic antimicrobial compounds. Nowadays, the most extensive research and commercial practices are based on probiotic bacteria. Probiotics, specifically lactic acid bacteria are widely used in the food industry for fermentation but have gained attention from health professionals because of their potential beneficial effects. Now probiotic therapy is thought to be an effective way to improve the gut health and an alternative to antibiotic treatments. They contribute to food safety by their ability to inhibit the growth of several other bacteria. LAB can be used as protective cultures to compete with potential pathogens and other undesired organisms, thereby increasing the safety of the food product.

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

    Directory of Open Access Journals (Sweden)

    Ki-Young Lee

    2016-10-01

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

  9. Horizontal gene transfers link a human MRSA pathogen to contagious bovine mastitis bacteria.

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    Thomas Brody

    Full Text Available BACKGROUND: Acquisition of virulence factors and antibiotic resistance by many clinically important bacteria can be traced to horizontal gene transfer (HGT between related or evolutionarily distant microflora. Comparative genomic analysis has become an important tool for identifying HGT DNA in emerging pathogens. We have adapted the multi-genome alignment tool EvoPrinter to facilitate discovery of HGT DNA sequences within bacterial genomes and within their mobile genetic elements. PRINCIPAL FINDINGS: EvoPrinter analysis of 13 different Staphylococcus aureus genomes revealed that one of the human isolates, the hospital epidemic methicillin-resistant MRSA252 strain, uniquely shares multiple putative HGT DNA sequences with different causative agents of bovine mastitis that are not found in the other human S. aureus isolates. MRSA252 shares over 14 different DNA sequence blocks with the bovine mastitis ET3 S. aureus strain RF122, and many of the HGT DNAs encode virulence factors. EvoPrinter analysis of the MRSA252 chromosome also uncovered virulence-factor encoding HGT events with the genome of Listeria monocytogenes and a Staphylococcus saprophyticus associated plasmid. Both bacteria are also causal agents of contagious bovine mastitis. CONCLUSIONS: EvoPrinter analysis reveals that the human MRSA252 strain uniquely shares multiple DNA sequence blocks with different causative agents of bovine mastitis, suggesting that HGT events may be occurring between these pathogens. These findings have important implications with regard to animal husbandry practices that inadvertently enhance the contact of human and livestock bacterial pathogens.

  10. Early immune response patterns to pathogenic bacteria are associated to increased risk of lower respiratory infections in children

    DEFF Research Database (Denmark)

    Vissing, N. H.; Larsen, Jeppe Madura; Rasmussen, Mette Annelie

    2014-01-01

    Neonatal colonisation of the airways with respiratory pathogens is associated with increased risk of lower respiratory infections (LRI) in early childhood (1). Therefore, we hypothesized that children developing LRI have an abnormal immune response to pathogenic bacteria in infancy. We aimed...

  11. Invariant natural killer T cells recognize glycolipids from pathogenic Gram-positive bacteria.

    Science.gov (United States)

    Kinjo, Yuki; Illarionov, Petr; Vela, José Luis; Pei, Bo; Girardi, Enrico; Li, Xiangming; Li, Yali; Imamura, Masakazu; Kaneko, Yukihiro; Okawara, Akiko; Miyazaki, Yoshitsugu; Gómez-Velasco, Anaximandro; Rogers, Paul; Dahesh, Samira; Uchiyama, Satoshi; Khurana, Archana; Kawahara, Kazuyoshi; Yesilkaya, Hasan; Andrew, Peter W; Wong, Chi-Huey; Kawakami, Kazuyoshi; Nizet, Victor; Besra, Gurdyal S; Tsuji, Moriya; Zajonc, Dirk M; Kronenberg, Mitchell

    2011-09-04

    Natural killer T cells (NKT cells) recognize glycolipid antigens presented by CD1d. These cells express an evolutionarily conserved, invariant T cell antigen receptor (TCR), but the forces that drive TCR conservation have remained uncertain. Here we show that NKT cells recognized diacylglycerol-containing glycolipids from Streptococcus pneumoniae, the leading cause of community-acquired pneumonia, and group B Streptococcus, which causes neonatal sepsis and meningitis. Furthermore, CD1d-dependent responses by NKT cells were required for activation and host protection. The glycolipid response was dependent on vaccenic acid, which is present in low concentrations in mammalian cells. Our results show how microbial lipids position the sugar for recognition by the invariant TCR and, most notably, extend the range of microbes recognized by this conserved TCR to several clinically important bacteria.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Salma [Iowa State Univ., Ames, IA (United States)

    2005-01-01

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

  13. ISOLATION RATE OF PATHOGENIC BACTERIA FROM SOME FOOD PRODUCTS IN TEHRAN

    Directory of Open Access Journals (Sweden)

    H. Salari

    2000-12-01

    Full Text Available Bacteria usually cause disease in the gastrointestinal tract by colonization and growth in the gastrointestinal tract, where the micro organisms may invade the tissues of host or secretion of an exotoxin that is performed in food and then ingested by the host, examples of second group include: staphylococcal, Bacillus cereus, clostridial (C.botulinum and C.perfringens type A toxin. In this study pathogenic bacteria of 350 food products by culture method were investigated. The results were obtained as follows: Bacillus cereus 12 cases (3.4, Staphylococcus coagulase positive 25(7.1%, Staphylococcus coagulase negative 37 (10.6%, Streptococcus alpha hemolysis 18 (5.1%, Enterococcus 3(0.8% and Klebsiella 5(1.4%.

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

    Science.gov (United States)

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

    2007-07-11

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

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

    Directory of Open Access Journals (Sweden)

    Brian C. Jester

    2012-01-01

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

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

    Science.gov (United States)

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

    2006-01-01

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

  17. Fourier Transform Infrared Spectroscopy (FTIR) as a Tool for the Identification and Differentiation of Pathogenic Bacteria.

    Science.gov (United States)

    Zarnowiec, Paulina; Lechowicz, Łukasz; Czerwonka, Grzegorz; Kaca, Wiesław

    2015-01-01

    Methods of human bacterial pathogen identification need to be fast, reliable, inexpensive, and time efficient. These requirements may be met by vibrational spectroscopic techniques. The method that is most often used for bacterial detection and identification is Fourier transform infrared spectroscopy (FTIR). It enables biochemical scans of whole bacterial cells or parts thereof at infrared frequencies (4,000-600 cm(-1)). The recorded spectra must be subsequently transformed in order to minimize data variability and to amplify the chemically-based spectral differences in order to facilitate spectra interpretation and analysis. In the next step, the transformed spectra are analyzed by data reduction tools, regression techniques, and classification methods. Chemometric analysis of FTIR spectra is a basic technique for discriminating between bacteria at the genus, species, and clonal levels. Examples of bacterial pathogen identification and methods of differentiation up to the clonal level, based on infrared spectroscopy, are presented below.

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

    Science.gov (United States)

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

    2006-09-01

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

  19. Protective effect of potentially probiotic Lactobacillus strain on infection with pathogenic bacteria in chickens.

    Science.gov (United States)

    Kizerwetter-Swida, M; Binek, M

    2009-01-01

    The probiotic potential of a Lactobacillus salivarius 3d strain isolated from chicken faeces was assessed in one day old chickens. Lactobacillus salivarius 3d was administered per os at a concentration of 10(8) cfu in 100 microl of PBS. The chickens were then challenged with pathogenic bacteria: Salmonella Enteritidis, Campylobacter jejuni and Clostridium perfringens. Samples of caecal contents and livers were collected after 1, 2, 3, 7 and 14 days after infection. Lactobacilli and pathogenic bacterial cell counts were determined in the samples. This study showed that L. salivarius 3d reduced the number of Salmonella Enteritidis and Clostridium perfringens in the group of chickens treated with Lactobacillus. Therefore it may be concluded that L. salivarius 3d may be used as a potential probiotic for chickens.

  20. ESSENTIAL OILS OF CYMBOPOGON SP. IN THE CONTROL OF FOODBORNE PATHOGENIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Danilo Florisvaldo BRUGNERA

    2011-08-01

    Full Text Available In this study, the agar well diffusion technique was used to determine the antibacterial activity of Cymbopogon nardus (citronella and Cymbopogon citratus (lemongrass essential oils, which were applied at different concentrations. The bacterial species used were the foodborne pathogens Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Both essential oils presented antibacterial activity in most concentrations tested. The Minimum Inhibitory Concentrations (MICs founded were: 7.81μL/mL (S. aureus and 3.90μL/mL (E. coli and P. aeruginosa, for C. nardus essential oil; and 3.90μL/mL (S. aureus, E. coli and P. aeruginosa, for C. citratus essential oil. The essential oils used were shown as promising natural antibacterials for pathogenic bacteria control in the food industry.

  1. 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.

  2. Pathogenic and Ice-Nucleation Active (INA) Bacteria causing Dieback of Willows in Short Rotation Forestry

    Energy Technology Data Exchange (ETDEWEB)

    Nejad, Pajand

    2005-03-01

    hypersensitive reaction in tobacco, as well as causing necrotic symptoms on willows exposed to frost treatment. The most frequently isolated types were found to be non-fluorescent P. fluorescens (biotype A, B, C, F, G) and/or Sphingomonas spp. Erwinia spp, P. fluorescens, Xanthomonas spp and P. syringae however, were considered to be the most important pathogens in the field. We conclude that diseases caused by INA bacteria in relationship with frost are a limiting factor in willow and poplar plantations in Sweden and most likely also in other temperate regions in the world.

  3. Activation of type III interferon genes by pathogenic bacteria in infected epithelial cells and mouse placenta.

    Directory of Open Access Journals (Sweden)

    Hélène Bierne

    Full Text Available Bacterial infections trigger the expression of type I and II interferon genes but little is known about their effect on type III interferon (IFN-λ genes, whose products play important roles in epithelial innate immunity against viruses. Here, we studied the expression of IFN-λ genes in cultured human epithelial cells infected with different pathogenic bacteria and in the mouse placenta infected with Listeria monocytogenes. We first showed that in intestinal LoVo cells, induction of IFN-λ genes by L. monocytogenes required bacterial entry and increased further during the bacterial intracellular phase of infection. Other Gram-positive bacteria, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis, also induced IFN-λ genes when internalized by LoVo cells. In contrast, Gram-negative bacteria Salmonella enterica serovar Typhimurium, Shigella flexneri and Chlamydia trachomatis did not substantially induce IFN-λ. We also found that IFN-λ genes were up-regulated in A549 lung epithelial cells infected with Mycobacterium tuberculosis and in HepG2 hepatocytes and BeWo trophoblastic cells infected with L. monocytogenes. In a humanized mouse line permissive to fetoplacental listeriosis, IFN-λ2/λ3 mRNA levels were enhanced in placentas infected with L. monocytogenes. In addition, the feto-placental tissue was responsive to IFN-λ2. Together, these results suggest that IFN-λ may be an important modulator of the immune response to Gram-positive intracellular bacteria in epithelial tissues.

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

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    Giuditta Fiorella Schiavano

    2016-01-01

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

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

    DEFF Research Database (Denmark)

    Breum Andersen, Sandra; Marvig, Rasmus Lykke; Molin, Søren;

    2015-01-01

    Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly...... social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find that Pseudomonas aeruginosa bacteria, causing lung...

  6. Harpins, multifunctional proteins secreted by gram-negative plant-pathogenic bacteria.

    Science.gov (United States)

    Choi, Min-Seon; Kim, Wooki; Lee, Chanhui; Oh, Chang-Sik

    2013-10-01

    Harpins are glycine-rich and heat-stable proteins that are secreted through type III secretion system in gram-negative plant-pathogenic bacteria. Many studies show that these proteins are mostly targeted to the extracellular space of plant tissues, unlike bacterial effector proteins that act inside the plant cells. Over the two decades since the first harpin of pathogen origin, HrpN of Erwinia amylovora, was reported in 1992 as a cell-free elicitor of hypersensitive response (HR), diverse functional aspects of harpins have been determined. Some harpins were shown to have virulence activity, probably because of their involvement in the translocation of effector proteins into plant cytoplasm. Based on this function, harpins are now considered to be translocators. Their abilities of pore formation in the artificial membrane, binding to lipid components, and oligomerization are consistent with this idea. When harpins are applied to plants directly or expressed in plant cells, these proteins trigger diverse beneficial responses such as induction of defense responses against diverse pathogens and insects and enhancement of plant growth. Therefore, in this review, we will summarize the functions of harpins as virulence factors (or translocators) of bacterial pathogens, elicitors of HR and immune responses, and plant growth enhancers.

  7. Evaluation of Antibacterial Activities of Citrus limon, Citrus reticulata, and Citrus grandis Against Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Sholeh Saeb

    2016-11-01

    Full Text Available Background: Microorganisms resistant to most antibiotics are rapidly spreading, and there is an urgent and continuous need for novel antimicrobial compounds. The genus Citrus belongs to the family Rutaceae has many biologically active secondary metabolites. Objectives: The purpose of this study was to evaluate antimicrobial activity of essential oil and extract of Lemon (Citrus limon, Mandarin (Citrus reticulata and Pummelo (Citrus grandis against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Salmonella typhi. Materials and Methods: The fresh Citrus leaves were shade-dried and powdered. Antimicrobial metabolites were extracted from them by 80% methanol for extract and using a Clevenger-type apparatus for essential oil. Eight different concentrations of the each leaf extract and essential oil were prepared. The antimicrobial susceptibility assay of Citrus leaves metabolites were subjected against four bacterial strains by agar disc diffusion and E-test method. Results: In this study, minimum inhibitory concentrations (MIC of different Citrus leaf extracts were determined against all four food-borne pathogens. The C. grandis leaf essential oil had potent antimicrobial activity against all four pathogens, and the C. limon leaf essential oil was effective on Gram-positive bacteria. S. typhi was resistant against two leaves essential oils. Conclusions: The results showed that there was no antimicrobial activity effect in all extracts on tested bacteria. In this study, the antibacterial effect of essential oil of Citrus leaves on four strains of pathogenic microorganisms was confirmed. The C. grandis leaf essential oil had the most powerful antimicrobial properties, suggesting its potential application as natural preservative in foods or an effective medicine against different pathogenic microbes. Key words: Antibacterial activity, E-test, Citr

  8. [Studies on rapid detection of food-borne pathogenic bacteria by nucleic acid testing and related technology].

    Science.gov (United States)

    Cao, Wei; Wang, Mingzhong; Wang, Xiaoying; Liu, Xiumei

    2008-03-01

    The traditional methods of bacteria isolation, cultivation and identification are time-consuming, which can't meet the needs of the control and prevention of food-borne diseases. Recently, various kinds of rapid methods for food-borne pathogenic bacteria detection have emerged with the prompt development of nucleic acid testing technology. The application studies on polymerase chain reaction and the techniques derived from it, nucleic acid isothermal amplification, oligonucleotide microarray, immunomagnetic separation and DNA biosensing on food-borne pathogenic bacteria including Salmonella, Staphylococcus aureus and Enterohemorrhagic Escherchia coli, etc. were reviewed.

  9. Genotoxic effects of fly ash in bacteria, mammalian cells and animals.

    Science.gov (United States)

    Morris, D L; Connor, T H; Harper, J B; Ward, J B; Legator, M S

    1989-01-01

    The increasing use of fossil fuels has raised concerns about possible deleterious health effects of the final combustion product, fly ash. Seven ash samples from coal sources obtained from Battelle Columbus Laboratories were evaluated in the Salmonella/mammalian microsome mutagenicity assay to determine their mutagenic potential. While dimethyl sulfoxide extracts of five samples showed no mutagenicity, sample 102 caused an increase in the number of revertants per plate over controls in TA100 and TA98 with activation by liver homogenate (2-fold and 2.4-fold, respectively), and without (2-fold and 6-fold). This ash was thus evaluated in whole animal studies. Animals treated by inhalation or oral gavage were assayed for the presence of mutagens in the urine, micronuclei in polychromatic erythrocytes, and chromosomal aberrations in metaphase bone marrow cells. Those animals treated by inhalation were also examined for local damage in the lung. The assay for mutagens in the urine was negative as shown by the Ames assay with TA100 and TA98 and there was no increase in micronuclei or in metaphase aberrations. Histological sections from the animals treated by inhalation did not show the presence of particles, macrophage infiltrations and generalized lung damage. We tested the same fly ash with an in vitro cell transformation assay with the cell line Balb/c 3T3 subclone A31-1-13. Although there was not an increase in Type III foci, there was a dose-dependent increase of Type II foci in the treated cells over the controls. In one assay, there was approximately a 14-fold increase in Type II foci in the highest dose (2 mg/ml) compared to the solvent control. One other ash sample induced cell transformation without being markedly cytotoxic, while a third sample was highly toxic but did not induce transformation.

  10. Small Molecule Membrane Transporters in the Mammalian Podocyte: A Pathogenic and Therapeutic Target

    Directory of Open Access Journals (Sweden)

    Cristina Zennaro

    2014-11-01

    Full Text Available The intriguingly complex glomerular podocyte has been a recent object of intense study. Researchers have sought to understand its role in the pathogenesis of common proteinuric diseases such as minimal change disease and focal segmental glomerular sclerosis. In particular, considerable effort has been directed towards the anatomic and functional barrier to macromolecular filtration provided by the secondary foot processes, but little attention has been paid to the potential of podocytes to handle plasma proteins beyond the specialization of the slit diaphragm. Renal membrane transporters in the proximal tubule have been extensively studied for decades, particularly in relation to drug metabolism and elimination. Recently, uptake and efflux transporters for small organic molecules have also been found in the glomerular podocyte, and we and others have found that these transporters can engage not only common pharmaceuticals but also injurious endogenous and exogenous agents. We have also found that the activity of podocyte transporters can be manipulated to inhibit pathogen uptake and efflux. It is conceivable that podocyte transporters may play a role in disease pathogenesis and may be a target for future drug development.

  11. A prebiotic role of Ecklonia cava improves the mortality of Edwardsiella tarda-infected zebrafish models via regulating the growth of lactic acid bacteria and pathogen bacteria.

    Science.gov (United States)

    Lee, WonWoo; Oh, Jae Young; Kim, Eun-A; Kang, Nalae; Kim, Kil-Nam; Ahn, Ginnae; Jeon, You-Jin

    2016-07-01

    In this study, the beneficial prebiotic roles of Ecklonia cava (E. cava, EC) were evaluated on the growth of lactic acid bacteria (LAB) and pathogen bacteria and the mortality of pathogen-bacteria infected zebrafish model. The result showed that the original E. cava (EC) led to the highest growth effects on three LABs (Lactobacillus brevis, L. brevis; Lactobacillus pentosus, L. pentosus; Lactobacillus plantarum; L. plantarum) and it was dose-dependent manners. Also, EC, its Celluclast enzymatic (ECC) and 100% ethanol extracts (ECE) showed the anti-bacterial activities on the fish pathogenic bacteria such as (Edwardsiella tarda; E. tarda, Streptococcus iniae; S. iniae, and Vibrio harveyi; V. harveyi). Interestingly, EC induced the higher production of the secondary metabolites from L. plantarum in MRS medium. The secondary metabolites produced by EC significantly inhibited the growth of pathogen bacteria. In further in vivo study, the co-treatment of EC and L. plantarum improved the growth and mortality of E. tarda-infected zebrafish as regulating the expression of inflammatory molecules such as iNOS and COX2. Taken together, our present study suggests that the EC plays an important role as a potential prebiotic and has a protective effect against the infection caused by E. tarda injection in zebrafish. Also, our conclusion from this evidence is that EC can be used and applied as a useful prebiotic.

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

    Science.gov (United States)

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

    2014-01-01

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

  13. Differential activity of a lectin from Solieria filiformis against human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    M.L. Holanda

    2005-12-01

    Full Text Available A lectin isolated from the red alga Solieria filiformis was evaluated for its effect on the growth of 8 gram-negative and 3 gram-positive bacteria cultivated in liquid medium (three independent experiments/bacterium. The lectin (500 µg/mL stimulated the growth of the gram-positive species Bacillus cereus and inhibited the growth of the gram-negative species Serratia marcescens, Salmonella typhi, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus sp, and Pseudomonas aeruginosa at 1000 µg/mL but the lectin (10-1000 µg/mL had no effect on the growth of the gram-positive bacteria Staphylococcus aureus and B. subtilis, or on the gram-negative bacteria Escherichia coli and Salmonella typhimurium. The purified lectin significantly reduced the cell density of gram-negative bacteria, although no changes in growth phases (log, exponential and of decline were observed. It is possible that the interaction of S. filiformis lectin with the cell surface receptors of gram-negative bacteria promotes alterations in the flow of nutrients, which would explain the bacteriostatic effect. Growth stimulation of the gram-positive bacterium B. cereus was more marked in the presence of the lectin at a concentration of 1000 µg/mL. The stimulation of the growth of B. cereus was not observed when the lectin was previously incubated with mannan (125 µg/mL, its hapten. Thus, we suggest the involvement of the binding site of the lectin in this effect. The present study reports the first data on the inhibition and stimulation of pathogenic bacterial cells by marine alga lectins.

  14. 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.

  15. Pathogenic bacteria target NEDD8-conjugated cullins to hijack host-cell signaling pathways.

    Directory of Open Access Journals (Sweden)

    Grégory Jubelin

    2010-09-01

    Full Text Available The cycle inhibiting factors (Cif, produced by pathogenic bacteria isolated from vertebrates and invertebrates, belong to a family of molecules called cyclomodulins that interfere with the eukaryotic cell cycle. Cif blocks the cell cycle at both the G₁/S and G₂/M transitions by inducing the stabilization of cyclin-dependent kinase inhibitors p21(waf1 and p27(kip1. Using yeast two-hybrid screens, we identified the ubiquitin-like protein NEDD8 as a target of Cif. Cif co-compartmentalized with NEDD8 in the host cell nucleus and induced accumulation of NEDD8-conjugated cullins. This accumulation occurred early after cell infection and correlated with that of p21 and p27. Co-immunoprecipitation revealed that Cif interacted with cullin-RING ubiquitin ligase complexes (CRLs through binding with the neddylated forms of cullins 1, 2, 3, 4A and 4B subunits of CRL. Using an in vitro ubiquitylation assay, we demonstrate that Cif directly inhibits the neddylated CUL1-associated ubiquitin ligase activity. Consistent with this inhibition and the interaction of Cif with several neddylated cullins, we further observed that Cif modulates the cellular half-lives of various CRL targets, which might contribute to the pathogenic potential of diverse bacteria.

  16. Association with pathogenic bacteria affects life-history traits and population growth in Caenorhabditis elegans.

    Science.gov (United States)

    Diaz, S Anaid; Mooring, Eric Q; Rens, Elisabeth G; Restif, Olivier

    2015-04-01

    Determining the relationship between individual life-history traits and population dynamics is an essential step to understand and predict natural selection. Model organisms that can be conveniently studied experimentally at both levels are invaluable to test the rich body of theoretical literature in this area. The nematode Caenorhabditis elegans, despite being a well-established workhorse in genetics, has only recently received attention from ecologists and evolutionary biologists, especially with respect to its association with pathogenic bacteria. In order to start filling the gap between the two areas, we conducted a series of experiments aiming at measuring life-history traits as well as population growth of C. elegans in response to three different bacterial strains: Escherichia coli OP50, Salmonella enterica Typhimurium, and Pseudomonas aeruginosa PAO1. Whereas previous studies had established that the latter two reduced the survival of nematodes feeding on them compared to E. coli OP50, we report for the first time an enhancement in reproductive success and population growth for worms feeding on S. enterica Typhimurium. Furthermore, we used an age-specific population dynamic model, parameterized using individual life-history assays, to successfully predict the growth of populations over three generations. This study paves the way for more detailed and quantitative experimental investigation of the ecology and evolution of C. elegans and the bacteria it interacts with, which could improve our understanding of the fate of opportunistic pathogens in the environment.

  17. [Two-component signal transduction as attractive drug targets in pathogenic bacteria].

    Science.gov (United States)

    Utsumi, Ryutaro; Igarashi, Masayuki

    2012-01-01

    Gene clusters contributing to processes such as cell growth and pathogenicity are often controlled by two-component signal transduction systems (TCSs). TCS consists of a histidine kinase (HK) and a response regulator (RR). TCSs are attractive as drug targets for antimicrobials because many HK and RR genes are coded on the bacterial genome though few are found in lower eukaryotes. The HK/RR signal transduction system is distinct from serine/threonine and tyrosine phosphorylation in higher eukaryotes. Specific inhibitors against TCS systems work differently from conventional antibiotics, and developing them into new drugs that are effective against various drug-resistant bacteria may be possible. Furthermore, inhibitors of TCSs that control virulence factors may reduce virulence without killing the pathogenic bacteria. Previous TCS inhibitors targeting the kinase domain of the histidine kinase sensor suffered from poor selectivity. Recent TCS inhibitors, however, target the sensory domains of the sensors blocking the quorum sensing system, or target the essential response regulator. These new targets are introduced, together with several specific TCSs that have the potential to serve as effective drug targets.

  18. Inexpensive and fast pathogenic bacteria screening using field-effect transistors.

    Science.gov (United States)

    Formisano, Nello; Bhalla, Nikhil; Heeran, Mel; Reyes Martinez, Juana; Sarkar, Amrita; Laabei, Maisem; Jolly, Pawan; Bowen, Chris R; Taylor, John T; Flitsch, Sabine; Estrela, Pedro

    2016-11-15

    While pathogenic bacteria contribute to a large number of globally important diseases and infections, current clinical diagnosis is based on processes that often involve culturing which can be time-consuming. Therefore, innovative, simple, rapid and low-cost solutions to effectively reduce the burden of bacterial infections are urgently needed. Here we demonstrate a label-free sensor for fast bacterial detection based on metal-oxide-semiconductor field-effect transistors (MOSFETs). The electric charge of bacteria binding to the glycosylated gates of a MOSFET enables quantification in a straightforward manner. We show that the limit of quantitation is 1.9×10(5) CFU/mL with this simple device, which is more than 10,000-times lower than is achieved with electrochemical impedance spectroscopy (EIS) and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-ToF) on the same modified surfaces. Moreover, the measurements are extremely fast and the sensor can be mass produced at trivial cost as a tool for initial screening of pathogens.

  19. Pathogenic bacteria target NEDD8-conjugated cullins to hijack host-cell signaling pathways.

    Science.gov (United States)

    Jubelin, Grégory; Taieb, Frédéric; Duda, David M; Hsu, Yun; Samba-Louaka, Ascel; Nobe, Rika; Penary, Marie; Watrin, Claude; Nougayrède, Jean-Philippe; Schulman, Brenda A; Stebbins, C Erec; Oswald, Eric

    2010-09-30

    The cycle inhibiting factors (Cif), produced by pathogenic bacteria isolated from vertebrates and invertebrates, belong to a family of molecules called cyclomodulins that interfere with the eukaryotic cell cycle. Cif blocks the cell cycle at both the G₁/S and G₂/M transitions by inducing the stabilization of cyclin-dependent kinase inhibitors p21(waf1) and p27(kip1). Using yeast two-hybrid screens, we identified the ubiquitin-like protein NEDD8 as a target of Cif. Cif co-compartmentalized with NEDD8 in the host cell nucleus and induced accumulation of NEDD8-conjugated cullins. This accumulation occurred early after cell infection and correlated with that of p21 and p27. Co-immunoprecipitation revealed that Cif interacted with cullin-RING ubiquitin ligase complexes (CRLs) through binding with the neddylated forms of cullins 1, 2, 3, 4A and 4B subunits of CRL. Using an in vitro ubiquitylation assay, we demonstrate that Cif directly inhibits the neddylated CUL1-associated ubiquitin ligase activity. Consistent with this inhibition and the interaction of Cif with several neddylated cullins, we further observed that Cif modulates the cellular half-lives of various CRL targets, which might contribute to the pathogenic potential of diverse bacteria.

  20. Mapping the amide I absorption in single bacteria and mammalian cells with resonant infrared nanospectroscopy

    Science.gov (United States)

    Baldassarre, L.; Giliberti, V.; Rosa, A.; Ortolani, M.; Bonamore, A.; Baiocco, P.; Kjoller, K.; Calvani, P.; Nucara, A.

    2016-02-01

    Infrared (IR) nanospectroscopy performed in conjunction with atomic force microscopy (AFM) is a novel, label-free spectroscopic technique that meets the increasing request for nano-imaging tools with chemical specificity in the field of life sciences. In the novel resonant version of AFM-IR, a mid-IR wavelength-tunable quantum cascade laser illuminates the sample below an AFM tip working in contact mode, and the repetition rate of the mid-IR pulses matches the cantilever mechanical resonance frequency. The AFM-IR signal is the amplitude of the cantilever oscillations driven by the thermal expansion of the sample after absorption of mid-IR radiation. Using purposely nanofabricated polymer samples, here we demonstrate that the AFM-IR signal increases linearly with the sample thickness t for t \\gt 50 nm, as expected from the thermal expansion model of the sample volume below the AFM tip. We then show the capability of the apparatus to derive information on the protein distribution in single cells through mapping of the AFM-IR signal related to the amide-I mid-IR absorption band at 1660 cm-1. In Escherichia Coli bacteria we see how the topography changes, observed when the cell hosts a protein over-expression plasmid, are correlated with the amide I signal intensity. In human HeLa cells we obtain evidence that the protein distribution in the cytoplasm and in the nucleus is uneven, with a lateral resolution better than 100 nm.

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

    Science.gov (United States)

    Perkins, Sarah D; Angenent, Largus T

    2010-12-01

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

  2. Control of Some Human Pathogenic Bacteria by Seed Extracts of Cumin (Cuminum cyminum L.

    Directory of Open Access Journals (Sweden)

    Mominul Islam Sheikh

    2014-02-01

    Full Text Available Antibacterial activity of seed extracts of cumin (Cuminum cyminum L. was investigated against 10 gram positive and gram negative bacteria. Disc diffusion method was used to test antibacterial activity. Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MBC were determined by using standard procedures. The highest (effective inhibition zone of 16.67±0.47 mm was found at 250 mg/ml for Escherichia coli. On the other hand, the inhibition zones 15.00±0.82 mm for ethanol, 15.33±0.47 for methanol, and 15.67±0.82 for acetone were found against Bacillus subtilis, Sarcina lutea and Klebsiella pneumonia, respectively. MIC value (20 to 50 mg/ml and MBC value (40 to 60 mg/ml were measured against studied bacteria. On the basis of investigation, we can say, cumin seeds could be used as a source of new antibacterial agent for developing drugs to inhibit some human pathogenic bacteria.

  3. Control of Some Human Pathogenic Bacteria by Seed Extracts of Cumin (Cuminum cyminum L.

    Directory of Open Access Journals (Sweden)

    Mominul Islam Sheikh

    2010-03-01

    Full Text Available Antibacterial activity of seed extracts of cumin (Cuminum cyminum L. was investigated against 10 gram positive and gram negative bacteria. Disc diffusion method was used to test antibacterial activity. Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MBC were determined by using standard procedures. The highest (effective inhibition zone of 16.67±0.47 mm was found at 250 mg/ml for Escherichia coli. On the other hand, the inhibition zones 15.00±0.82 mm for ethanol, 15.33±0.47 for methanol, and 15.67±0.82 for acetone were found against Bacillus subtilis, Sarcina lutea and Klebsiella pneumonia, respectively. MIC value (20 to 50 mg/ml and MBC value (40 to 60 mg/ml were measured against studied bacteria. On the basis of investigation, we can say, cumin seeds could be used as a source of new antibacterial agent for developing drugs to inhibit some human pathogenic bacteria.

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

    Science.gov (United States)

    Benz, Roland

    2016-03-01

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

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

    Science.gov (United States)

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

    1998-05-01

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

  6. Antimicrobial activity of phenolics and glucosinolate hydrolysis products and their synergy with streptomycin against pathogenic bacteria.

    Science.gov (United States)

    Saavedra, Maria J; Borges, Anabela; Dias, Carla; Aires, Alfredo; Bennett, Richard N; Rosa, Eduardo S; Simões, Manuel

    2010-05-01

    The purpose of the present study was to evaluate the in vitro antibacterial effects of different classes of important and common dietary phytochemicals (5 simple phenolics - tyrosol, gallic acid, caffeic acid, ferulic acid, and chlorogenic acid; chalcone - phloridzin; flavan-3-ol - (-) epicatechin; seco-iridoid - oleuropein glucoside; 3 glucosinolate hydrolysis products - allylisothiocyanate, benzylisothiocyanate and 2-phenylethylisothiocyanate) against Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus. Another objective of this study was to evaluate the effects of dual combinations of streptomycin with the different phytochemicals on antibacterial activity. A disc diffusion assay was used to evaluate the antibacterial activity of the phytochemicals and 3 standard antibiotics (ciprofloxacin, gentamicin and streptomycin) against the four bacteria. The antimicrobial activity of single compounds and dual combinations (streptomycin-phytochemicals) were quantitatively assessed by measuring the inhibitory halos. The results showed that all of the isothiocyanates had significant antimicrobial activities, while the phenolics were much less efficient. No antimicrobial activity was observed with phloridzin. In general P. aeruginosa was the most sensitive microorganism and L. monocytogenes the most resistant. The application of dual combinations demonstrated synergy between streptomycin and gallic acid, ferulic acid, chlorogenic acid, allylisothiocyanate and 2-phenylethylisothiocyanate against the Gram-negative bacteria. In conclusion, phytochemical products and more specifically the isothiocyanates were effective inhibitors of the in vitro growth of the Gram-negative and Gram-positive pathogenic bacteria. Moreover, they can act synergistically with less efficient antibiotics to control bacterial growth.

  7. [Distribution and antibiotics resistance related to nosocomial pathogenic bacteria infection in patients after cardiac surgery].

    Science.gov (United States)

    Dang, Hai-ming; Song, Yue; Cao, Jian; Wu, Li-song; Dong, Ran

    2013-05-01

    To investigate the clinical distribution and antibiotics resistance of nosocomial infection caused pathogenic bacteria in patients after cardiac surgery. Clinical data from 612 patients after cardiac surgery under microbiologically documented nosocomial infection was retrospectively analyzed from January 2007 to December 2012. Identification on related bacterial was performed in an automatic ATB Expression system while antimicrobial susceptibility was tested by Kirby-Bauer method. were analyzed by WHONET5.4. There were 697 strains of clinical pathogenic bacilli isolates identified and 421 (60.4%) of them were isolated from sputum while 185 (26.5%) were from blood. Acinetobacter spp. (124 strains, 17.8%), Pseudomonas aeruginosa (85 strains, 12.2%) and Klebsiella pneumoniae (50 strains, 7.2%) were the predominant Gram-negative bacilli while S. epidermidis (75 strains, 10.8%) was the predominant Gram-positive cocci. The predominant eumycete was Candida albicans (43 strains, 6.2%). from the susceptibility test showed that carbapenems, cefoperazone/sulbactam and piperacillin/tazobactam were the most active antibiotics. The detection of meticillin-resistant Staphylococcus (MRS) were 82.9% in S aureus and 95.9% in coagulase negative Staphylococcus. There was no Staphylococcus strains resistant to vancomycin found. Non-fermenting Gram-negative bacilli and Staphylococcus appeared the important pathogens in patients after cardiac surgery. Drug resistance to antibiotics was quite common. Prevention on nosocomial infection and rational use of antibiotics remained very important in reducing the amount of drug resistant strains.

  8. 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

  9. The blow fly, Chrysomya megacephala, and the house fly, Musca domestica, as mechanical vectors of pathogenic bacteria in Northeast Thailand.

    Science.gov (United States)

    Chaiwong, T; Srivoramas, T; Sueabsamran, P; Sukontason, K; Sanford, M R; Sukontason, K L

    2014-06-01

    The Oriental latrine fly, Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) and the house fly, Musca domestica L., (Diptera: Muscidae) are synanthropic flies which are adapted to live in close association with human habitations, thereby making them likely mechanical vectors of several pathogens to humans. There were two main aims of this study. The first aim was to determine the prevalence of these two fly species from five types of human habitations including: fresh-food markets, garbage piles, restaurants, school cafeterias and paddy fields, in the Muang Ubon Ratchathani and Warinchamrap districts of Ubon Ratchathani province of Northeast Thailand. Flies collection were conducted monthly from September 2010-October 2011 using a reconstructable funnel trap, containing 1 day-tainted beef offal as bait. A total of 7 750 flies (6 401 C. megacephala and 1 349 M.domestica) were collected. The second aim was to examine the potential of these flies to carry pathogenic bacteria. Bacteria were isolated from 994 individual flies collected using a sweep net (555 C. megacephala and 439 M. domestica). A total of 15 bacterial genera were isolated from the external surfaces, comprising ten genera of gram-negative bacteria and five gram-positive bacteria. The most common bacteria isolated from both species were coagulase-negative staphylococci, followed by Streptococcus group D non-enterococci. Human pathogenic enteric bacteria isolated were Salmonella sp., Shigella sp., Escherichia coli O157:H7, Salmonella typhi, Bacillus sp., and Enterococcus sp., of which S. typhi is the first report of isolation from these fly species. Other human pathogens included Staphylococcus aureus and Pseudomonas aeruginosa. Not only were the number of C. megacephala positive for bacteria significantly higher than for M. domestica, but they were also carrying ~11-12 times greater bacterial load than M. domestica. These data suggest that both fly species should be considered potential

  10. P-Ser-HPr-a link between carbon metabolism and the virulence of some pathogenic bacteria

    DEFF Research Database (Denmark)

    Mijakovic, Ivan

    2005-01-01

    HPr kinase/phosphorylase phosphorylates HPr, a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system, at serine-46. P-Ser-HPr is the central regulator of carbon metabolism in Gram-positive bacteria, but also plays a role in virulence development of certain...... pathogens. In Listeria monocytogenes, several virulence genes, which depend on the transcription activator PrfA, are repressed by glucose, fructose, etc., in a catabolite repressor (CcpA)-independent mechanism. However, the catabolite co-repressor P-Ser-HPr was found to inhibit the activity of Prf...... is probably also mediated via P-Ser-HPr, since ccpA disruption leads to elevated amounts of P-Ser-HPr. Indeed, a ccpA ptsH1 double mutant exhibited normal PrfA activity. In S. pyogenes, the expression of several virulence genes depends on the transcription activator Mga. Interestingly, the mga promoter...

  11. A study of bactericidal effect and optimization of pathogenic bacteria using TiO2 photocatalyst.

    Science.gov (United States)

    Kim, Tae-Young; Park, Seung-Shik; Kim, Seung-Jai; Cho, Sung-Young

    2011-02-01

    The photocatalytic degradation of Salmonella choleraesuis subsp. and Vibrio parahaemolyticus in water by TiO2 catalysts was investigated in a batch reactor. After 30 min of irradiation with UV light in the presence of 1 mg/ml of TiO2, death ratio of S. choleraesuis subsp. and V. parahaemolyticus was 60% and 83%, respectively. And complete killing of the cells was achieved after 3 h of illumination in the presence of TiO2. We established the response surface methodology to investigate the effect of principal parameters on the pathogenic bacteria sterilization such as TiO2 concentration, pH and temperature. By applying response surface analysis to the bactericidal effect of S. almonella choleraesuis subsp. and V. parahaemolyticus, we found that the cell death ratio was influenced significantly by the first order term of TiO2 concentration.

  12. Prevalence of indicator and pathogenic bacteria in a tropical river of Western Ghats, India

    Science.gov (United States)

    Vincy, M. V.; Brilliant, R.; Pradeepkumar, A. P.

    2017-05-01

    The Meenachil, the only river that flows through the heart of the Kottayam district of Kerala state, India was selected for the study. The present study has been carried out with an objective to systematically examine the prevalence of indicator and pathogenic microorganisms and to compare the microbiological quality of the river water during the pre-monsoon and post-monsoon seasons. Water samples from 44 different sites during pre-monsoon and post-monsoon seasons were collected for the analysis. During the pre-monsoon period, the faecal coliform count ranged from 230 to 110,000 MPN/100 ml while there was a variation from 200 to 4600 MPN/100 ml during the post-monsoon period. When the faecal streptococci count was analysed, it ranged from 140 to 110,000 MPN/100 ml during the pre-monsoon and 70 to 4600 MPN/100 ml during the post-monsoon seasons, respectively. All the samples collected were found to have total viable count (TVC) higher than those prescribed by Bureau of Indian Standards (ISI 1991). Total viable counts were found in the range of 1.1 × 102 to 32 × 102 cfu/ml in the pre-monsoon and 1.0 × 102 to 26 × 102 cfu/ml in the post-monsoon. The presence of faecal indicator bacteria, Escherichia coli and potentially pathogenic bacteria, Vibrio cholerae, Vibrio parahaemolyticus and Salmonella enterica in the Meenachil River indicates that the bacteriological quality of the Meenachil River is poor. Moreover, it sheds light to the fact that raw sewage is being dumped into the Meenachil River. Urban runoffs and effluents of rubber factories appear to be the important sources of faecal contamination in the river. From this study, we conclude that these water bodies pose significant public health hazards. Adequate sanitary infrastructure will help in preventing source water contamination. Besides this, public health education aimed at improving personal, household and community hygiene is urgent.

  13. 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.

  14. Phenotypic and genetic diversity of rice seed-associated bacteria and their role in pathogenicity and biological control.

    Science.gov (United States)

    Cottyn, B; Debode, J; Regalado, E; Mew, T W; Swings, J

    2009-09-01

    To study the phenotypic and genetic diversity of culturable bacteria associated with rice seed and to asses the antagonistic and pathogenic potential of the isolated bacteria. Seed of rice cultivar PSBRc14 was collected from farmers' fields of irrigated lowland in southern Luzon, Philippines. Isolations of distinct colonies yielded 498 isolates. Classification of the isolates according to similarities in cellular characteristics, whole-cell fatty acid composition, and colony appearance differentiated 101 morphotype groups. Predominant bacteria were Coryneform spp., Pantoea spp. and Pseudomonas spp. Other bacteria regularly present were Actinomycetes spp., Bacillus pumilus, B. subtilis, Burkholderia glumae, Enterobacter cloacae, Paenibacillus polymyxa, Staphylococcus spp. and Xanthomonas spp. The genetic diversity among isolates was assessed by BOX-PCR fingerprinting of genomic DNA and represented 284 fingerprint types (FPTs). Most FPTs (78%) were not shared among samples, while eight FPTs occurred frequently in the samples. Seven of these FPTs also occurred frequently in a previous collection made from rainfed lowlands of Iloilo island, Philippines. Sixteen per cent of the isolates inhibited in vitro the mycelial growth of the rice pathogens Rhizoctonia solani and Pyricularia grisea, whereas 4% were pathogens identified as Burkholderia glumae, Burkholderia gladioli and Acidovorax avenae ssp. avenae. This study reveals a broad morphological and genetic diversity of bacteria present on seed of a single rice cultivar. This line of work contributes to a better understanding of the microbial diversity present on rice seed and stresses its importance as a carrier of antagonists and pathogens.

  15. The inhibitory effect of Thymus vulgaris extracts on the planktonic form and biofilm structures of six human pathogenic bacteria

    OpenAIRE

    Zinab Mohsenipour; Mehdi Hassanshahian

    2015-01-01

    Objective: Microorganisms are responsible for many problems in industry and medicine because of biofilm formation. Therefore, this study was aimed to examine the effect of Thymus vulgaris (T. vulgaris) extracts on the planktonic form and biofilm structures of six pathogenic bacteria. Materials and methods: Antimicrobial activities of the plant extracts against the planktonic form of the bacteria were determined using the disc diffusion method. MIC and MBC values were evaluated using macrobrot...

  16. Influence of river discharge on abundance and dissemination of heterotrophic, indicator and pathogenic bacteria along the east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Prasad, V.R.; Srinivas, T.N.R.; Sarma, V.V.S.S.

    and pathogenic bacteria, has a vital position in marine pollution studies, as this gives an unswerving consequence of pollution on human health and also other marine biota. Hence it is crucial to observe microbial load in marine environments to warrant... of marine resources that pose a human health hazard and subsequent economic loss. Higher abundance of different bacteria was observed off Visakhapatnam city due to the intensive anthropogenic activities. Besides highlighting significant correlations...

  17. Single walled carbon nanotube-based electrical biosensor for the label-free detection of pathogenic bacteria

    DEFF Research Database (Denmark)

    Yoo, S. M.; Baek, Y. K.; Shin, S.

    2016-01-01

    We herein describe the development of a single-walled carbon nanotube (SWNT)-based electrical biosensor consisting of a two-terminal resistor, and report its use for the specific, label-free detection of pathogenic bacteria via changes in conductance. The ability of this biosensor to recognize....... This SWNT-based electrical biosensor will prove useful for the development of highly sensitive and specific handheld pathogen detectors....

  18. Prewashing with acidified sodium chlorite reduces pathogenic bacteria in lightly fermented Chinese cabbage.

    Science.gov (United States)

    Inatsu, Yasuhiro; Maeda, Yutaka; Bari, M L; Kawasaki, Susumu; Kawamoto, Shinichi

    2005-05-01

    Efficacy of prewashing with acidified sodium chlorite (ASC) for the sanitation of lightly fermented Chinese cabbage was evaluated. The population of the natural microflora on the cabbage leaves was reduced about 2.0 log CFU/g just after washing with ASC, a significant reduction compared with the control distilled water wash (P < or = 0.05). In the control experiment, viable aerobic bacteria increased gradually when incubated at 10 degrees C; however, ASC-washed cabbage maintained a lower microbial concentration. The treatment of Chinese cabbage with ASC reduced the population of artificially inoculated Escherichia coli O157:H7, Salmonella Enteritidis, Staphylococcus aureus, and Listeria monocytogenes by 2.4 log CFU/g. The sanitation efficacy of ASC was 1.6 log CFU/g higher than that of distilled water washing. The viable cell counts of all pathogenic bacteria tested remained constant during 8 days of storage at 10 degrees C for both washing treatments, with the exception of L. monocytogenes, whose viable cell counts increased gradually with time for both treatments. No significant differences in color, odor, taste, and texture in raw leaves were observed after the ASC wash compared with after the distilled water wash. These results indicate that prewashing with ASC could control bacterial growth in lightly fermented Chinese cabbage without changing the product quality.

  19. Antimicrobial Activity of Kefir against Various Food Pathogens and Spoilage Bacteria.

    Science.gov (United States)

    Kim, Dong-Hyeon; Jeong, Dana; Kim, Hyunsook; Kang, Il-Byeong; Chon, Jung-Whan; Song, Kwang-Young; Seo, Kun-Ho

    2016-01-01

    Kefir is a unique fermented dairy product produced by a mixture of lactic acid bacteria, acetic acid bacteria, and yeast. Here, we compared the antimicrobial spectra of four types of kefirs (A, L, M, and S) fermented for 24, 36, 48, or 72 h against eight food-borne pathogens. Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis, Escherichia coli, Salmonella Enteritidis, Pseudomonas aeruginosa, and Cronobacter sakazakii were used as test strains, and antibacterial activity was investigated by the spot on lawn method. The spectra, potencies, and onsets of activity varied according to the type of kefir and the fermentation time. The broadest and strongest antimicrobial spectrum was obtained after at least 36-48 h of fermentation for all kefirs, although the traditional fermentation method of kefir is for 18-24 h at 25℃. For kefir A, B. cereus, E. coli, S. Enteritidis, P. aeruginosa, and C. sakazakii were inhibited, while B. cereus, S. aureus, E. coli, S. Enteritidis, P. aeruginosa, and C. sakazakii were inhibited to different extents by kefirs L, M, and S. Remarkably, S. aureus, S. Enteritidis, and C. sakazakii were only inhibited by kefirs L, M, and S, and L. monocytogenes by kefir M after fermentation for specific times, suggesting that the antimicrobial activity is attributable not only to a low pH but also to antimicrobial substances secreted during the fermentation.

  20. Diversity of honey stores and their impact on pathogenic bacteria of the honeybee, Apis mellifera.

    Science.gov (United States)

    Erler, Silvio; Denner, Andreas; Bobiş, Otilia; Forsgren, Eva; Moritz, Robin F A

    2014-10-01

    Honeybee colonies offer an excellent environment for microbial pathogen development. The highest virulent, colony killing, bacterial agents are Paenibacillus larvae causing American foulbrood (AFB), and European foulbrood (EFB) associated bacteria. Besides the innate immune defense, honeybees evolved behavioral defenses to combat infections. Foraging of antimicrobial plant compounds plays a key role for this "social immunity" behavior. Secondary plant metabolites in floral nectar are known for their antimicrobial effects. Yet, these compounds are highly plant specific, and the effects on bee health will depend on the floral origin of the honey produced. As worker bees not only feed themselves, but also the larvae and other colony members, honey is a prime candidate acting as self-medication agent in honeybee colonies to prevent or decrease infections. Here, we test eight AFB and EFB bacterial strains and the growth inhibitory activity of three honey types. Using a high-throughput cell growth assay, we show that all honeys have high growth inhibitory activity and the two monofloral honeys appeared to be strain specific. The specificity of the monofloral honeys and the strong antimicrobial potential of the polyfloral honey suggest that the diversity of honeys in the honey stores of a colony may be highly adaptive for its "social immunity" against the highly diverse suite of pathogens encountered in nature. This ecological diversity may therefore operate similar to the well-known effects of host genetic variance in the arms race between host and parasite.

  1. Short communication: Lactic acid bacteria from the honeybee inhibit the in vitro growth of mastitis pathogens.

    Science.gov (United States)

    Piccart, K; Vásquez, A; Piepers, S; De Vliegher, S; Olofsson, T C

    2016-04-01

    Despite the increasing knowledge of prevention and control strategies, bovine mastitis remains one of the most challenging diseases in the dairy industry. This study investigated the antimicrobial activity of 13 species of lactic acid bacteria (LAB), previously isolated from the honey crop of the honeybee, on several mastitis pathogens. The viable LAB were first reintroduced into a sterilized heather honey matrix. More than 20 different bovine mastitis isolates were tested against the mixture of the 13 LAB species in the honey medium using a dual-culture overlay assay. The mastitis isolates were identified through bacteriological culturing, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Additionally, the mastitis isolates were subjected to antimicrobial susceptibility testing through disk diffusion. Growth of all tested mastitis pathogens, including the ones displaying antimicrobial resistance to one or more antimicrobial compounds, were inhibited to some extent by the honey and LAB combination. The antibacterial effect of these LAB opens up new perspectives on alternative treatment and prevention of bovine mastitis.

  2. Bactericidal efficacy of elevated pH on fish pathogenic and environmental bacteria

    Directory of Open Access Journals (Sweden)

    Clifford E. Starliper

    2013-07-01

    Full Text Available Ship ballast water is a recognized medium for transfer and introductions of nonindigenous species. There is a need for new ballast water treatment methods that effectively and safely eliminate or greatly minimize movements of these species. The present study employed laboratory methods to evaluate the bactericidal efficacy of increased pH (pH 10.0–12.0 for exposure durations of up to 72 h to kill a variety of Gram-negative and Gram-positive bacteria including fish pathogens (Aeromonas spp., Yersinia ruckeri, Edwardsiella ictaluri, Serratia liquefaciens, Carnobacterium sp., other common aquatic-inhabitant bacteria (Serratia marcescens, Pseudomonas fluorescens, Staphylococcus sp., Bacillus sp. and indicators listed in International Maritime Organization D2 Standards; namely, Vibrio cholera (an environmental isolate from fish, Escherichia coli and Enterococcus faecalis. Volumes of 5 N NaOH were added to tryptic soy broth to obtain desired pH adjustments. Viable cells were determined after 0, 4, 12, 24, 48, and 72 h. Initial (0 h cell numbers ranged from 3.40 × 104 cfu/mL for Bacillus sp. to 2.44 × 107 cfu/mL for E. faecalis. The effective endpoints of pH and treatment duration necessary to realize 100% bactericidal effect varied; however, all bacteria tested were killed within 72 h at pH 12.0 or lower. The lowest parameters examined, 4 h at pH 10.0, were bactericidal to V. cholera, E. ictaluri, three of four isolates of E. coli, and (three of four Aeromonas salmonicida subsp. salmonicida. Bactericidal effect was attained at pH 10.0 within 12 h for the other A. salmonicida subsp. salmonicida, and within 24 h for P. fluorescens, and the remaining E. coli.

  3. Bactericidal efficacy of elevated pH on fish pathogenic and environmental bacteria

    Science.gov (United States)

    Starliper, Clifford E.; Watten, Barnaby J.

    2013-01-01

    Ship ballast water is a recognized medium for transfer and introductions of nonindigenous species. There is a need for new ballast water treatment methods that effectively and safely eliminate or greatly minimize movements of these species. The present study employed laboratory methods to evaluate the bactericidal efficacy of increased pH (pH 10.0–12.0) for exposure durations of up to 72 h to kill a variety of Gram-negative and Gram-positive bacteria including fish pathogens (Aeromonas spp., Yersinia ruckeri, Edwardsiella ictaluri, Serratia liquefaciens, Carnobacterium sp.), other common aquatic-inhabitant bacteria (Serratia marcescens, Pseudomonas fluorescens, Staphylococcus sp., Bacillus sp.) and indicators listed in International Maritime Organization D2 Standards; namely, Vibrio cholera (an environmental isolate from fish), Escherichia coli and Enterococcus faecalis. Volumes of 5 N NaOH were added to tryptic soy broth to obtain desired pH adjustments. Viable cells were determined after 0, 4, 12, 24, 48, and 72 h. Initial (0 h) cell numbers ranged from 3.40 × 104 cfu/mL for Bacillus sp. to 2.44 × 107 cfu/mL for E. faecalis. The effective endpoints of pH and treatment duration necessary to realize 100% bactericidal effect varied; however, all bacteria tested were killed within 72 h at pH 12.0 or lower. The lowest parameters examined, 4 h at pH 10.0, were bactericidal to V. cholera, E. ictaluri, three of four isolates of E. coli, and (three of four) Aeromonas salmonicida subsp. salmonicida. Bactericidal effect was attained at pH 10.0 within 12 h for the other A. salmonicida subsp. salmonicida, and within 24 h for P. fluorescens, and the remaining E. coli.

  4. Evaluation of Antibacterial Activity and Preliminary Phytochemical Screening of Moringa oleifera on Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Ogah James Ode

    2015-11-01

    Full Text Available The use of higher plants and their extracts to treat infections is an old practice in traditional African medicine. However, scientific research has shown that bioactive compounds in plants are valuable medically in the treatment of infections caused by pathogenic microorganisms. This research work is aimed to evaluate the antibacterial potential of Moringa oleifera extracts on standard microorganisms strains as well as multi-drug resistant strains of medical importance. Acetone, aqueous, ethanol and chloroform extracts of bark, leaves and seeds of Moringa oleifera were investigated for antibacterial activity against Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Methicillin resistant Staphylococcus aureus (MRSA, Pseudomonas aeruginosa and Proteus mirabilis. The preliminary phytochemical screening and antibacterial assay were carried out using chemicals and agar well diffusion method respectively. The results of phytochemicals analysis revealed differences in the presence of alkaloids, reducing sugars, saponins and volatile oil in all the extracts. Tannins were present in the extract of leaves while terpenes were present in the extract of bark and leaves. Phlobatannins and flavonoids were absent in all the extracts. The antibacterial assay results showed that M. oleifera extracts exhibited broad spectrum activity against four to six bacteria isolates as indicated by the zone of inhibition ranging from 10 to 36mm with variation in the percentage sensitivity of < 100%, = 100% and >100% depending on the plant part and solvent used. The minimum inhibitory concentration (MIC and bactericidal concentration (MBC ranged from 100mg/ml to 450mg/ml and 250mg/ml to 500mg/ml respectively against the isolates used. Standard antibiotic disc (Ofloxacin- 5μg inhibited the growth of all the tested bacteria isolates except P. mirabilis. The results of this research work showed that M. oleifera has great potential as antibacterial compounds against Gram

  5. Antimicrobial Activity of Croton macrostachyus Stem Bark Extracts against Several Human Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Jackie K. Obey

    2016-01-01

    Full Text Available In Kenya, leaves and roots from Croton macrostachyus are used as a traditional medicine for infectious diseases such as typhoid and measles, but reports on possible antimicrobial activity of stem bark do not exist. In this study, the antibacterial and antifungal effects of methanol, ethyl acetate and butanol extracts, and purified lupeol of C. macrostachyus stem bark were determined against important human gram-negative pathogens Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, and Enterobacter aerogenes, gram-positive Listeria monocytogenes, and a fungus Candida albicans. The most promising broad scale antimicrobial activity against all the studied pathogens was shown by the ethyl acetate extract. The ethyl acetate extract induced the zone of inhibition between 10.1±0.6 mm and 16.0±1.2 mm against S. typhi, E. coli, K. pneumoniae, E. aerogenes, and L. monocytogenes with weaker antimicrobial activity against C. albicans (zone of inhibition: 5.6±1.0 mm. The antibiotic controls (amoxicillin, ciprofloxacin, ampicillin, benzylpenicillin, clotrimazole, and cefotaxime showed antimicrobial activity with zones of inhibition within 13.4±0.7–22.1±0.9 mm. The ethyl acetate extract had MIC in the range of 125–250 mg/mL against all the studied bacteria and against C. albicans MIC was 500 mg/mL. The present results give scientific evidence and support the traditional use of C. macrostachyus stem bark as a source for antimicrobials. We show that C. macrostachyus stem bark lupeol is a promising antimicrobial agent against several important human pathogens.

  6. Antimicrobial Activity of Croton macrostachyus Stem Bark Extracts against Several Human Pathogenic Bacteria

    Science.gov (United States)

    Obey, Jackie K.; von Wright, Atte; Orjala, Jimmy; Kauhanen, Jussi; Tikkanen-Kaukanen, Carina

    2016-01-01

    In Kenya, leaves and roots from Croton macrostachyus are used as a traditional medicine for infectious diseases such as typhoid and measles, but reports on possible antimicrobial activity of stem bark do not exist. In this study, the antibacterial and antifungal effects of methanol, ethyl acetate and butanol extracts, and purified lupeol of C. macrostachyus stem bark were determined against important human gram-negative pathogens Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, and Enterobacter aerogenes, gram-positive Listeria monocytogenes, and a fungus Candida albicans. The most promising broad scale antimicrobial activity against all the studied pathogens was shown by the ethyl acetate extract. The ethyl acetate extract induced the zone of inhibition between 10.1 ± 0.6 mm and 16.0 ± 1.2 mm against S. typhi, E. coli, K. pneumoniae, E. aerogenes, and L. monocytogenes with weaker antimicrobial activity against C. albicans (zone of inhibition: 5.6 ± 1.0 mm). The antibiotic controls (amoxicillin, ciprofloxacin, ampicillin, benzylpenicillin, clotrimazole, and cefotaxime) showed antimicrobial activity with zones of inhibition within 13.4 ± 0.7–22.1 ± 0.9 mm. The ethyl acetate extract had MIC in the range of 125–250 mg/mL against all the studied bacteria and against C. albicans MIC was 500 mg/mL. The present results give scientific evidence and support the traditional use of C. macrostachyus stem bark as a source for antimicrobials. We show that C. macrostachyus stem bark lupeol is a promising antimicrobial agent against several important human pathogens. PMID:27293897

  7. Peracetic Acid (PAA Disinfection: Inactivation of Microbial Indicators and Pathogenic Bacteria in a Municipal Wastewater Plant

    Directory of Open Access Journals (Sweden)

    Silvia Bonetta

    2017-06-01

    Full Text Available Several studies have noted that treated and untreated wastewaters are primary contributors of a variety of pathogenic microorganisms to the aquatic ecosystem. Conventional wastewater treatment may not be sufficient to achieve microbiologically safe effluent to be discharged into natural waters or reused, thus requiring wastewater effluents to be disinfected. In recent years, peracetic acid (PAA has been adopted as a disinfectant for wastewater effluents. The aim of this study was to evaluate the disinfection efficiency of PAA at low doses (range 0.99–2.10 mg/L against microbial indicators and pathogenic bacteria in a municipal wastewater plant. Samples of untreated sewage and effluents before and after PAA treatment were collected seasonally for 1 year and were analysed for pathogenic Campylobacter, Salmonella spp., E. coli O157:H7 and E. coli virulence genes using molecular methods; moreover, the detection of specific microbial indicators (E. coli, faecal coliforms, enterococci, C. perfringens and Salmonella spp. were carried out using culturing methods. Salmonella spp. DNA was found in all untreated sewage and effluent before PAA treatment, whereas it was recovered in 50% of the samples collected after PAA treatment. Although E. coli O157:H7 was never identified, the occurrence of Shiga-like toxin I amplicons was identified in 75% of the untreated sewage samples, in 50% of the effluents assayed before PAA treatment, and in 25% of the effluents assayed after PAA treatment, whereas the stx2 gene was never found. Campylobacter coli was only detected in one effluent sample before PAA treatment. In the effluents after PAA treatment, a lower load of indicator bacteria was observed compared to the effluents before treatment. The results of this study highlight that the use of low doses of PAA seems to lead to an improvement of the microbiological quality of the effluent, although it is not sufficient to guarantee its suitability for irrigation

  8. Distribution of 1 037 strains of pathogenic bacteria and antibiotic resistance of the main pathogenic bacteria analysis%1037株病原菌分布及其主要病原菌耐药情况分析

    Institute of Scientific and Technical Information of China (English)

    潘开拓; 姜朝新; 王陈龙; 黄燕新; 曾令恒; 曾庆洋

    2013-01-01

      目的分析佛山市南海区第三人民医院检出的病原菌分布及其主要病原菌耐药情况,为临床合理用药和控制医院感染提供依据.方法采用法国生物梅里埃公司ATB微生物鉴定仪对2010年1月至2011年12月从该院患者的各类标本中分离的1037株病原菌进行鉴定,药敏试验采用琼脂纸片扩散法及法国生物梅里埃ATB药敏板条.结果检出病原菌以革兰阴性杆菌为主占58.4%、革兰阳性球菌次之占27.3%,真菌占13.2%,除真菌外的其他主要病原菌的抗菌药物耐药率普遍较高.结论医院容易发生医院感染,应加强其病原菌分布及其抗菌药物耐药情况监测,以指导临床合理用药,降低医院感染率.%Objective To analyze the distribution of pathogenic bacteria isolated from our hospital and the an-tibiotic resistance of the main pathogenic bacteria ,to provide a basis for clinical rational drug use and control the hos-pital infection .Methods 1 037 strains of pathogenic bacteria separated from patients in our hospital during Jan 2010-Dec 2011 were identified by ATB biomerieux from France and detected the antibiotic resistance by Kirby-Bauer(K-B) agar tape diffusion and drug sensitivity test tape of ATB biomerieux from France .Results The Gram-negative bacte-ria(58 .4% ) were the main pathogenic bacteria ,as followed by Gram-positive bacteria(27 .3% ) ,and fungi(13 .2% ) . The antibiotic resistance rates of the main pathogenic bacteria except fungi were high .Conclusion Patients easily suffered hospital infection ,it should strengthen the monitoring of the distribution of pathogenic bacteria and their an-tibiotic resistance so as to help the doctors to choose the antibiotics reasonably and reduce the rate of hospital infec-tion .

  9. Cultivation and qPCR detection of pathogenic and antibiotic resistant bacteria establishment in naive broiler houses

    Science.gov (United States)

    : Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space, atop bedding material such as pine shavings or rice hulls, for approximately 6.5 weeks. This environment is known for harboring pathogens and antibiotic resistant bacteria, but ...

  10. The application of flow cytometry and fluorescent probe technology for detection and assessment of viability of plant pathogenic bacteria

    NARCIS (Netherlands)

    Chitarra, L.G.; Bulk, van den R.W.

    2003-01-01

    Conventional methods to detect and assess the viability of plant pathogenic bacteria are usually based on plating assays or serological techniques. Plating assays provide information about the number of viable cells, expressed as colony-forming units, but are time-consuming and laborious.

  11. The application of flow cytometry and fluorescent probe technology for detection and assessment of viability of plant pathogenic bacteria

    NARCIS (Netherlands)

    Chitarra, L.G.; Bulk, van den R.W.

    2003-01-01

    Conventional methods to detect and assess the viability of plant pathogenic bacteria are usually based on plating assays or serological techniques. Plating assays provide information about the number of viable cells, expressed as colony-forming units, but are time-consuming and laborious. Serologica

  12. Synergistic and antagonistic effect of lactic acid bacteria on tyramine production by food-borne pathogenic bacteria in tyrosine decarboxylase broth.

    Science.gov (United States)

    Kuley, Esmeray; Ozogul, Fatih

    2011-08-01

    The effect of lactic acid bacteria (LAB) strains on tyramine (TYR) and also other biogenic amines (BA) production by eight common food-borne pathogen (FBP) in tyrosine decarboxylase broth (TDB) was investigated by using a rapid HPLC method. Significant differences were observed among the FBP strains in ammonia (AMN) and BA production apart from tryptamine, histamine (HIS) and spermine formation (pfood-borne pathogenic bacteria, although the effect of some LAB strains on BA production was strain-dependent. Lactococcus spp. and Streptococcus spp. resulted in significantly higher TYR accumulation by Aeromonas hydrophila and Enterococcus faecalis in TDB. The presence of Lactococcus and/or Lactobacillus in TDB significantly increased HIS production by A. hydrophila, Escherichia coli, Ent. faecalis, Klebsiella pneumoniae and Pseudomonas aeruginosa, whereas HIS accumulation was significantly reduced by Staphylococcus aureus, S. paratyphi A and Listeria monocytogenes.

  13. Susceptibility to Lower Respiratory Infections in Childhood is Associated with Perturbation of the Cytokine Response to Pathogenic Airway Bacteria

    DEFF Research Database (Denmark)

    Vissing, Nadja Hawwa; Larsen, Jeppe Madura; Rasmussen, Morten Arendt

    2016-01-01

    BACKGROUND: Neonatal colonization of the airways with respiratory pathogens is associated with increased risk of lower respiratory infections (LRI) in early childhood. Therefore, we hypothesized that children developing LRI have an aberrant immune response to pathogenic bacteria in infancy....... OBJECTIVE: To characterize in vitro the early life systemic immune response to pathogenic bacteria and study the possible association with incidence of LRI during the first 3 years of life. METHODS: The Copenhagen Prospective Study on Asthma in Childhood2000 (COPSAC2000) is a clinical birth cohort study......, IL-5, IL-10, IL-13, and IL-17 in peripheral blood mononuclear cells isolated at age 6 months from 291 infants. Data were analyzed by Poisson regression against incidence of LRI in infancy. RESULTS:: A multivariable model including all cytokine responses from the three different bacterial stimulations...

  14. Occurrence and distribution of fecal indicator bacteria and gene markers of pathogenic bacteria in Great Lakes tributaries, March-October 2011

    Science.gov (United States)

    Brennan, Angela K.; Johnson, Heather E.; Totten, Alexander R.; Duris, Joseph W.

    2015-01-01

    From March through October 2011, the U.S. Geological Survey (USGS), conducted a study to determine the frequency of occurrence of pathogen gene markers and densities of fecal indicator bacteria (FIB) in 22 tributaries to the Great Lakes. This project was funded as part of the Great Lakes Restoration Initiative (GLRI) and included sampling at 22 locations throughout 6 states that border the Great Lakes.

  15. Combined antibacterial activity of stingless bee (Apis mellipodae) honey and garlic (Allium sativum) extracts against standard and clinical pathogenic bacteria.

    Science.gov (United States)

    Andualem, Berhanu

    2013-09-01

    To investigate the synergic antibacterial activity of garlic and tazma honey against standard and clinical pathogenic bacteria. Antimicrobial activity of tazma honey, garlic and mixture of them against pathogenic bacteria were determined. Chloramphenicol and water were used as positive and negative controls, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration of antimicrobial samples were determined using standard methods. Inhibition zone of mixture of garlic and tazma honey against all tested pathogens was significantly (P≤0.05) greater than garlic and tazma honey alone. The diameter zone of inhibition ranged from (18±1) to (35±1) mm for mixture of garlic and tazma honey, (12±1) to (20±1) mm for tazma honey and (14±1) to (22±1) mm for garlic as compared with (10±1) to (30±1) mm for chloramphenicol. The combination of garlic and tazma honey (30-35 mm) was more significantly (P≤0.05) effective against Salmonella (NCTC 8385), Staphylococcus aureus (ATCC 25923), Lyesria moncytogenes (ATCC 19116) and Streptococcus pneumonia (ATCC 63). Results also showed considerable antimicrobial activity of garlic and tazma honey. MIC of mixture of garlic and tazma honey at 6.25% against total test bacteria was 88.9%. MIC of mixture of garlic and tazma honey at 6.25% against Gram positive and negative were 100% and 83.33%, respectively. The bactericidal activities of garlic, tazma honey, and mixture of garlic and tazma honey against all pathogenic bacteria at 6.25% concentration were 66.6%, 55.6% and 55.6%, respectively. This finding strongly supports the claim of the local community to use the combination of tazma honey and garlic for the treatment of different pathogenic bacterial infections. Therefore, garlic in combination with tazma honey can serve as an alternative natural antimicrobial drug for the treatment of pathogenic bacterial infections. Further in vivo study is recommended to come up with a comprehensive conclusion.

  16. Effects of the Essential Oil from Origanum vulgare L. on Survival of Pathogenic Bacteria and Starter Lactic Acid Bacteria in Semihard Cheese Broth and Slurry.

    Science.gov (United States)

    de Souza, Geany Targino; de Carvalho, Rayssa Julliane; de Sousa, Jossana Pereira; Tavares, Josean Fechine; Schaffner, Donald; de Souza, Evandro Leite; Magnani, Marciane

    2016-02-01

    This study assessed the inhibitory effects of the essential oil from Origanum vulgare L. (OVEO) on Staphylococcus aureus, Listeria monocytogenes, and a mesophilic starter coculture composed of lactic acid bacteria (Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris) in Brazilian coalho cheese systems. The MIC of OVEO was 2.5 μl/ml against both S. aureus and L. monocytogenes and 0.6 μl/ml against the tested starter coculture. In cheese broth containing OVEO at 0.6 μl/ml, no decrease in viable cell counts (VCC) of both pathogenic bacteria was observed, whereas the initial VCC of the starter coculture decreased approximately 1.0 log CFU/ml after 24 h of exposure at 10°C. OVEO at 1.25 and 2.5 μl/ml caused reductions of up to 2.0 and 2.5 log CFU/ml in S. aureus and L. monocytogenes, respectively, after 24 h of exposure in cheese broth. At these same concentrations, OVEO caused a greater decrease of initial VCC of the starter coculture following 4 h of exposure. Higher concentrations of OVEO were required to decrease the VCC of all target bacteria in semisolid coalho cheese slurry compared with cheese broth. The VCC of Lactococcus spp. in coalho cheese slurry containing OVEO were always lower than those of pathogenic bacteria under the same conditions. These results suggest that the concentrations of OVEO used to control pathogenic bacteria in semihard cheese should be carefully evaluated because of its inhibitory effects on the growth of starter lactic acid cultures used during the production of the product.

  17. Studies on water quality and pathogenic bacteria in coastal water Langkawi, Malaysia.

    Science.gov (United States)

    Jalal, K C A; Faizul, H N Noor; Naim, M Azrul; John, B Akbar; Kamaruzzaman, B Y

    2012-07-01

    A study on physico-chemical parameters and pathogenic bacterial community was carried out at the coastal waters of Pulau Tuba island, Langkawi. The physico-chemical parameters such as temperature (27.43-28.88 degrees C), dissolved oxygen (3.79-6.49 mg l(-1)), pH (7.72-8.20), salinity (33.10-33.96 ppt), total dissolved solids (32.27-32.77 g l(-1)) and specific conductivity (49.83-51.63 mS cm(-1)) were observed. Station 3 and station 4 showed highest amount of nitrates (26.93 and 14.61 microg at N l(-1)) than station 1 (2.04 microg at N l(-1)) and station 2 (4.18 microg at N l(-1)). The highest concentration (12.4 +/- microg l(-1)) of chlorophyll a was observed in station 4 in October 2005. High phosphorus content (561 microg P l(-1)) was found in the station 2. Thirteen bacterial isolates were successfully identified using API 20E system. The highest amount of bacteria was observed at Station 4 (3400 CFU ml(-1)) and the lowest numberwas at Station 2 (890 CFU ml(-1)). Out of identified 13 Gram-negative bacterial isolates dominant species were Aeromonas hydrophila, Klebsiella oxytoca, Pseudomonas baumannii, Vibrio vulnificus, Proteus mirabilis, Providencia alcalifaciens and Serratia liquefaciens. Apart from this, oil biodegrading Pseudomonas putida were also identified. The study reveals the existing status of water quality is still conducive and the reasonably diverse with Gram-negative bacteria along the Pulau Tuba Langkawi.

  18. Antibacterial Activities of Metabolites from Platanus occidentalis (American sycamore) against Fish Pathogenic Bacteria

    Science.gov (United States)

    Schrader, Kevin K; Hamann, Mark T; McChesney, James D; Rodenburg, Douglas L; Ibrahim, Mohamed A

    2016-01-01

    One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentally safe natural compounds as alternatives to antibiotics would benefit the aquaculture industries. Four natural compounds, commonly called platanosides, [kaempferol 3-O-α-L-(2″,3″-di-E-p-coumaroyl)rhamnoside (1), kaempferol 3-O-α-L-(2″-E-p-coumaroyl-3″-Z-p-coumaroyl)rhamnoside (2), kaempferol 3-O-α-L-(2″-Z-p-coumaroyl-3″-E-p-coumaroyl)rhamnoside (3), and kaempferol 3-O-α-L-(2″,3″-di-Z-p-coumaroyl)rhamnoside (4)] isolated from the leaves of the American sycamore (Platanus occidentalis) tree were evaluated using a rapid bioassay for their antibacterial activities against common fish pathogenic bacteria including Flavobacterium columnare, Edwardsiella ictaluri, Aeromonas hydrophila, and Streptococcus iniae. The four isomers and a mixture of all four isomers were strongly antibacterial against isolates of F. columnare and S. iniae. Against F. columnare ALM-00-173, 3 and 4 showed the strongest antibacterial activities, with 24-h 50% inhibition concentration (IC50) values of 2.13 ± 0.11 and 2.62 ± 0.23 mg/L, respectively. Against S. iniae LA94-426, 4 had the strongest antibacterial activity, with 24-h IC50 of 1.87 ± 0.23 mg/L. Neither a mixture of the isomers nor any of the individual isomers were antibacterial against isolates of E. ictaluri and A. hydrophila at the test concentrations used in the study. Several of the isomers appear promising for the potential management of columnaris disease and streptococcosis in fish.

  19. Simultaneous detection of pathogenic bacteria using agglutination test based on colored silica nanoparticles.

    Science.gov (United States)

    Yu, Hui; Zhao, Guangying; Dou, Wenchao

    2015-01-01

    Aimed to explore an agglutination test which can simultaneously detect two pathogenic bacteria, an agglutination test based on colored silica nanoparticles (colored-SiNps) was established in this work. Monodisperse colored-SiNps were used as agglutination test carriers; red-SiNps and blue-SiNps were prepared by reverse microemulsion with C.I. Reactive red 136 and C.I. Reactive Blue 14. Then the red-SiNps were sensitized with antibodies against E. sakazaki and denoted as IgG-red-SiNps; The blue-SiNps were coated with antibodies against S. pullorum and S. Gallinarum and denoted as IgGblue- SiNps. The mixture solution of IgG-red-SiNps and IgG-blue-SiNps could simultaneously agglutinate with E. sakazakii and S. pullorum and S. gallinarum on glass slide. The E. sakazakii and S. pullorum and S. gallinarum could be simultaneously detected by agglutination test with obvious agglutination phenomena. The E. sakazakii and S. pullorum and S. gallinarum could both be detected in a range from 4×10(3) to 4×10(9) CFU/mL. The pullorum and S. gallinarum and E. sakazakii in the infected food sample were detected by mixture solution of IgG-red-SiNps and IgG-blue-SiNps too. This agglutination test was easy and rapid, it might be useful for in situ rapid detection method for simultaneously screening different pathogenic microorganisms of foods and feeds in the field.

  20. ß-defensin-2 in breast milk displays a broad antimicrobial activity against pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Joanna Baricelli

    2015-02-01

    Full Text Available OBJECTIVE: To describe the antimicrobial activity of ß-defensin-2 produced in the mammary gland and secreted in human breast milk. METHODS: The peptide production was performed by DNA cloning. ß-defensin-2 levels were quantified in 61 colostrum samples and 39 mature milk samples from healthy donors, by an indirect enzyme-linked immunosorbent assay (ELISA. Using halo inhibition assay, this study assessed activity against seven clinical isolates from diarrheal feces of children between 0 and 2 years of age. The activity of ß-defensin-2 against three opportunistic pathogens that can cause nosocomial infections was determined by microdilution test. RESULTS: The peptide levels were higher in colostrum (n = 61 than in mature milk samples (n = 39, as follows: median and range, 8.52 (2.6-16.3 µg/ml versus 0.97 (0.22-3.78, p < 0.0001; Mann-Whitney test. The recombinant peptide obtained showed high antimicrobial activity against a broad range of pathogenic bacteria. Its antibacterial activity was demonstrated in a disk containing between 1-4 µg, which produced inhibition zones ranging from 18 to 30 mm against three isolates of Salmonella spp. and four of E. coli. ß-defensin-2 showed minimum inhibitory concentrations (MICs of 0.25 µg/mL and 0.5 µg/mL for S. marcescen and P. aeruginosa, respectively, while a higher MIC (4 µg/mL was obtained against an isolated of multidrug-resistant strain of A. baumannii. CONCLUSIONS: To the authors' knowledge, this study is the first to report ß-defensin-2 levels in Latin American women. The production and the activity of ß-defensin-2 in breast milk prove its importance as a defense molecule for intestinal health in pediatric patients.

  1. Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

    Science.gov (United States)

    Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

    2016-11-01

    Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

  2. Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools.

    Science.gov (United States)

    Bittar, Fadi; Keita, Mamadou B; Lagier, Jean-Christophe; Peeters, Martine; Delaporte, Eric; Raoult, Didier

    2014-11-24

    Wild apes are considered to be the most serious reservoir and source of zoonoses. However, little data are available about the gut microbiota and pathogenic bacteria in gorillas. For this propose, a total of 48 fecal samples obtained from 21 Gorilla gorilla gorilla individuals (as revealed via microsatellite analysis) were screened for human bacterial pathogens using culturomics and molecular techniques. By applying culturomics to one index gorilla and using specific media supplemented by plants, we tested 12,800 colonies and identified 147 different bacterial species, including 5 new species. Many opportunistic pathogens were isolated, including 8 frequently associated with human diseases; Mycobacterium bolletii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Staphylococcus aureus and Clostridium botulinum. The genus Treponema accounted for 27.4% of the total reads identified at the genus level via 454 pyrosequencing. Using specific real-time PCR on 48 gorilla fecal samples, in addition to classical human pathogens, we also observed the fastidious bacteria Bartonella spp. Borrelia spp., Coxiella burnetii and Tropheryma whipplei in the gorilla population. We estimated that the prevalence of these pathogens vary between 4.76% and 85.7%. Therefore, gorillas share many bacterial pathogens with humans suggesting that they could be a reservoir for their emergence.

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

    Science.gov (United States)

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

    2016-01-01

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

  4. Persistence and potential Viable but Non-culturable state of pathogenic bacteria during storage of digestates from agricultural biogas plants

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    Geraldine Maynaud

    2016-09-01

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

  5. 613株病原菌分布及其主要耐药情况分析%Distribution of 613 Strains of Pathogenic Bacteria and Antibiotic Resistance of the Main Pathogenic Bacteria analysis

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Objective To analyze the distribution of pathogenic bacteria isolated from our hospital and the antibiotic resistance of the main pathogenic bacteria ,to provide a basis for clinical rational drug use and control the hospital infection .Methods 613 strains of pathogenic bacteria separated from patients in our hospital during June to December of 2012 were identifited by Hengxing bacteria analysis and detected the antibiotic resistance by Kirby-Bauer(K-B) agar tapediffusion. Results We gather 613 strains in last year of 2012,there were 417 strains Gram-negative bacteria (68%),128 strains Gram-positive bacteria(20.8%),and 68 strains fungi(13.2%), obviously the antibiotic resistance of pathogenic bacteria was higer than first half year.Conclusion It is necessary to reasonably use antibiotics,strengthen the awareness of bacteria culture and strictly comply the standards of diagnosis and antibiotic use so as to prevent the antibiotic resistanc of pathogenic bacteria. Gram-negative bacteria was the main pathogenic bacteria,clinician should ware the infection of Gram-negative bacteria.%  目的分析故城县医院检出的病原菌分布及其主要病原菌的耐药情况,为临床合理用药和控制医院感染提供参考。方法采用恒星细菌分析系统对2012年6月至2012年12月分离的613株病原菌进行鉴定,药敏试验采用琼脂纸片扩散法。结果2012年下半年共收集非重复临床分离菌株613株,其中革兰阴性菌417株占68%,革兰阳性菌128株占20.8%,真菌68株占11.2%,除真菌外其他病原菌的耐药率较之上半年都明显增加。结论应完善抗菌药物的规范使用,加强细菌培养意识,严格控制医院感染病例的诊断和用药标准,预防抗菌药物耐药率的快速产生。革兰阴性杆菌在住院患者感染中占主要地位,临床医师应警惕革兰阴性菌引起的感染。

  6. Antibacterial activity of plasma from crocodile (Crocodylus siamensis against pathogenic bacteria

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    Kommanee Jintana

    2012-07-01

    , perturbing and damaging bacterial membranes. The effect of the crude plasma was not toxic by the yellow tetrazolium bromide (MTT assay using a macrophage-like cell, RAW 264.7. The pooled four fractions, designated as fractions D1-D4, were obtained by column chromatography, and only fraction D1 showed growth inhibition in the reference strains and the clinical, human pathogenic isolates. Conclusions The crude and purified plasma from the Siamese crocodile significantly showed antibacterial activity against pathogenic bacteria and reference strains by damage cell membrane of target bacterial cells. From the MTT assay, the Siamese crocodile plasma was not cytotoxic to the cells.

  7. Selected Pathogens of Concern to Industrial Food Processors: Infectious, Toxigenic, Toxico-Infectious, Selected Emerging Pathogenic Bacteria

    Science.gov (United States)

    Behling, Robert G.; Eifert, Joseph; Erickson, Marilyn C.; Gurtler, Joshua B.; Kornacki, Jeffrey L.; Line, Erick; Radcliff, Roy; Ryser, Elliot T.; Stawick, Bradley; Yan, Zhinong

    This chapter, written by several contributing authors, is devoted to discussing selected microbes of contemporary importance. Microbes from three categories are described by the following: (1) infectious invasive agents like Salmonella, Listeria monocytogenes, and Campylobacter; (2) toxigenic pathogens such as Staphylococcus aureus, Bacillus cereus, and Clostridium botulinum; and (3) toxico-infectious agents like enterohemorrhagic Escherichia coli and Clostridium perfringens. In addition, emerging pathogens, like Cronobacter (Enterobacter) sakazakii, Arcobacter spp., and Mycobacterium avium subspecies paratuberculosis are also described.

  8. Oligo-DNA custom macroarray for monitoring major pathogenic and non-pathogenic fungi and bacteria in the phyllosphere of apple trees.

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    Ying-Hong He

    Full Text Available BACKGROUND: To monitor the richness in microbial inhabitants in the phyllosphere of apple trees cultivated under various cultural and environmental conditions, we developed an oligo-DNA macroarray for major pathogenic and non-pathogenic fungi and bacteria inhabiting the phyllosphere of apple trees. METHODS AND FINDINGS: First, we isolated culturable fungi and bacteria from apple orchards by an agar-plate culture method, and detected 32 fungal and 34 bacterial species. Alternaria, Aureobasidium, Cladosporium, Rhodotorula, Cystofilobasidium, and Epicoccum genera were predominant among the fungi, and Bacillus, Pseudomonas, Sphingomonas, Methylobacterium, and Pantoea genera were predominant among the bacteria. Based on the data, we selected 29 major non-pathogenic and 12 phytopathogenic fungi and bacteria as the targets of macroarray. Forty-one species-specific 40-base pair long oligo-DNA sequences were selected from the nucleotide sequences of rDNA-internal transcribed spacer region for fungi and 16S rDNA for bacteria. The oligo-DNAs were fixed on nylon membrane and hybridized with digoxigenin-labeled cRNA probes prepared for each species. All arrays except those for Alternaria, Bacillus, and their related species, were specifically hybridized. The array was sensitive enough to detect 10(3 CFU for Aureobasidium pullulans and Bacillus cereus. Nucleotide sequencing of 100 each of independent fungal rDNA-ITS and bacterial 16S-rDNA sequences from apple tree was in agreement with the macroarray data obtained using the same sample. Finally, we analyzed the richness in the microbial inhabitants in the samples collected from apple trees in four orchards. Major apple pathogens that cause scab, Alternaria blotch, and Marssonina blotch were detected along with several non-phytopathogenic fungal and bacterial inhabitants. CONCLUSIONS: The macroarray technique presented here is a strong tool to monitor the major microbial species and the community structures in

  9. HVEM signalling at mucosal barriers provides host defence against pathogenic bacteria.

    Science.gov (United States)

    Shui, Jr-Wen; Larange, Alexandre; Kim, Gisen; Vela, Jose Luis; Zahner, Sonja; Cheroutre, Hilde; Kronenberg, Mitchell

    2012-08-09

    The herpes virus entry mediator (HVEM), a member of the tumour-necrosis factor receptor family, has diverse functions, augmenting or inhibiting the immune response. HVEM was recently reported as a colitis risk locus in patients, and in a mouse model of colitis we demonstrated an anti-inflammatory role for HVEM, but its mechanism of action in the mucosal immune system was unknown. Here we report an important role for epithelial HVEM in innate mucosal defence against pathogenic bacteria. HVEM enhances immune responses by NF-κB-inducing kinase-dependent Stat3 activation, which promotes the epithelial expression of genes important for immunity. During intestinal Citrobacter rodentium infection, a mouse model for enteropathogenic Escherichia coli infection, Hvem−/− mice showed decreased Stat3 activation, impaired responses in the colon, higher bacterial burdens and increased mortality. We identified the immunoglobulin superfamily molecule CD160 (refs 7 and 8), expressed predominantly by innate-like intraepithelial lymphocytes, as the ligand engaging epithelial HVEM for host protection. Likewise, in pulmonary Streptococcus pneumoniae infection, HVEM is also required for host defence. Our results pinpoint HVEM as an important orchestrator of mucosal immunity, integrating signals from innate lymphocytes to induce optimal epithelial Stat3 activation, which indicates that targeting HVEM with agonists could improve host defence.

  10. Sugar fatty acid esters inhibit biofilm formation by food-borne pathogenic bacteria

    Science.gov (United States)

    Furukawa, Soichi; Akiyoshi, Yuko; O’Toole, George A.; Ogihara, Hirokazu; Morinaga, Yasushi

    2010-01-01

    Effects of food additives on biofilm formation by food-borne pathogenic bacteria were investigated. Thirty-three potential food additives and 3 related compounds were added to the culture medium at concentrations from 0.001 to 0.1% (w/w), followed by inoculation and cultivation of five biofilm-forming bacterial strains for the evaluation of biofilm formation. Among the tested food additives, 21 showed inhibitory effects of biofilm formation by Staphylococcus aureus and Escherichia coli, and in particular, sugar fatty acid esters showed significant anti-biofilm activity. Sugar fatty acid esters with long chain fatty acid residues (C14-16) exerted their inhibitory effect at the concentration of 0.001%(w/w), but bacterial growth was not affected at this low concentration. Activities of the sugar fatty acid esters positively correlated with the increase of the chain length of the fatty acid residues. Sugar fatty acid esters inhibited the initial attachment of the Staphylococcus aureus cells to the abiotic surface. Sugar fatty acid esters with long chain fatty acid residues (C14-16) also inhibited biofilm formation by Streptococcus mutans and Listeria monocytogenes at 0.01%(w/w), while the inhibition of biofilm formation by Pseudomonas aeruginosa required the addition of a far higher concentration (0.1%(w/w)) of the sugar fatty acid esters. PMID:20089325

  11. Marine Antimicrobial Peptides: Nature Provides Templates for the Design of Novel Compounds against Pathogenic Bacteria

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    Annarita Falanga

    2016-05-01

    Full Text Available The discovery of antibiotics for the treatment of bacterial infections brought the idea that bacteria would no longer endanger human health. However, bacterial diseases still represent a worldwide treat. The ability of microorganisms to develop resistance, together with the indiscriminate use of antibiotics, is mainly responsible for this situation; thus, resistance has compelled the scientific community to search for novel therapeutics. In this scenario, antimicrobial peptides (AMPs provide a promising strategy against a wide array of pathogenic microorganisms, being able to act directly as antimicrobial agents but also being important regulators of the innate immune system. This review is an attempt to explore marine AMPs as a rich source of molecules with antimicrobial activity. In fact, the sea is poorly explored in terms of AMPs, but it represents a resource with plentiful antibacterial agents performing their role in a harsh environment. For the application of AMPs in the medical field limitations correlated to their peptide nature, their inactivation by environmental pH, presence of salts, proteases, or other components have to be solved. Thus, these peptides may act as templates for the design of more potent and less toxic compounds.

  12. Sugar fatty acid esters inhibit biofilm formation by food-borne pathogenic bacteria.

    Science.gov (United States)

    Furukawa, Soichi; Akiyoshi, Yuko; O'Toole, George A; Ogihara, Hirokazu; Morinaga, Yasushi

    2010-03-31

    Effects of food additives on biofilm formation by food-borne pathogenic bacteria were investigated. Thirty-three potential food additives and 3 related compounds were added to the culture medium at concentrations from 0.001 to 0.1% (w/w), followed by inoculation and cultivation of five biofilm-forming bacterial strains for the evaluation of biofilm formation. Among the tested food additives, 21 showed inhibitory effects of biofilm formation by Staphylococcus aureus and Escherichia coli, and in particular, sugar fatty acid esters showed significant anti-biofilm activity. Sugar fatty acid esters with long chain fatty acid residues (C14-16) exerted their inhibitory effect at the concentration of 0.001% (w/w), but bacterial growth was not affected at this low concentration. Activities of the sugar fatty acid esters positively correlated with the increase of the chain length of the fatty acid residues. Sugar fatty acid esters inhibited the initial attachment of the S. aureus cells to the abiotic surface. Sugar fatty acid esters with long chain fatty acid residues (C14-16) also inhibited biofilm formation by Streptococcus mutans and Listeria monocytogenes at 0.01% (w/w), while the inhibition of biofilm formation by Pseudomonas aeruginosa required the addition of a far higher concentration (0.1% (w/w)) of the sugar fatty acid esters.

  13. Rapid Detection of Pathogenic Bacteria from Fresh Produce by Filtration and Surface-Enhanced Raman Spectroscopy

    Science.gov (United States)

    Wu, Xiaomeng; Han, Caiqin; Chen, Jing; Huang, Yao-Wen; Zhao, Yiping

    2016-04-01

    The detection of Salmonella Poona from cantaloupe cubes and E. coli O157:H7 from lettuce has been explored by using a filtration method and surface-enhanced Raman spectroscopy (SERS) based on vancomycin-functionalized silver nanorod array substrates. It is found that with a two-step filtration process, the limit of detection (LOD) of Salmonella Poona from cantaloupe cubes can be as low as 100 CFU/mL in less than 4 h, whereas the chlorophyll in the lettuce causes severe SERS spectral interference. To improve the LOD of lettuce, a three-step filtration method with a hydrophobic filter is proposed. The hydrophobic filter can effectively eliminate the interferences from chlorophyll and achieve a LOD of 1000 CFU/mL detection of E. coli O157:H7 from lettuce samples within 5 h. With the low LODs and rapid detection time, the SERS biosensing platform has demonstrated its potential as a rapid, simple, and inexpensive means for pathogenic bacteria detection from fresh produce.

  14. Perforin-2 is essential for intracellular defense of parenchymal cells and phagocytes against pathogenic bacteria.

    Science.gov (United States)

    McCormack, Ryan M; de Armas, Lesley R; Shiratsuchi, Motoaki; Fiorentino, Desiree G; Olsson, Melissa L; Lichtenheld, Mathias G; Morales, Alejo; Lyapichev, Kirill; Gonzalez, Louis E; Strbo, Natasa; Sukumar, Neelima; Stojadinovic, Olivera; Plano, Gregory V; Munson, George P; Tomic-Canic, Marjana; Kirsner, Robert S; Russell, David G; Podack, Eckhard R

    2015-09-24

    Perforin-2 (MPEG1) is a pore-forming, antibacterial protein with broad-spectrum activity. Perforin-2 is expressed constitutively in phagocytes and inducibly in parenchymal, tissue-forming cells. In vitro, Perforin-2 prevents the intracellular replication and proliferation of bacterial pathogens in these cells. Perforin-2 knockout mice are unable to control the systemic dissemination of methicillin-resistant Staphylococcus aureus (MRSA) or Salmonella typhimurium and perish shortly after epicutaneous or orogastric infection respectively. In contrast, Perforin-2-sufficient littermates clear the infection. Perforin-2 is a transmembrane protein of cytosolic vesicles -derived from multiple organelles- that translocate to and fuse with bacterium containing vesicles. Subsequently, Perforin-2 polymerizes and forms large clusters of 100 Å pores in the bacterial surface with Perforin-2 cleavage products present in bacteria. Perforin-2 is also required for the bactericidal activity of reactive oxygen and nitrogen species and hydrolytic enzymes. Perforin-2 constitutes a novel and apparently essential bactericidal effector molecule of the innate immune system.

  15. Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland

    Science.gov (United States)

    Nally, Jarlath E.; Arent, Zbigniew; Bayles, Darrell O.; Hornsby, Richard L.; Gilmore, Colm; Regan, Siobhan; McDevitt, Allan D.; Yearsley, Jon; Fanning, Séamus; McMahon, Barry J.

    2016-01-01

    The greater white-toothed shrew (Crocidura russula) is an invasive mammalian species that was first recorded in Ireland in 2007. It currently occupies an area of approximately 7,600 km2 on the island. C. russula is normally distributed in Northern Africa and Western Europe, and was previously absent from the British Isles. Whilst invasive species can have dramatic and rapid impacts on faunal and floral communities, they may also be carriers of pathogens facilitating disease transmission in potentially naive populations. Pathogenic leptospires are endemic in Ireland and a significant cause of human and animal disease. From 18 trapped C. russula, 3 isolates of Leptospira were cultured. However, typing of these isolates by standard serological reference methods was negative, and suggested an, as yet, unidentified serovar. Sequence analysis of 16S ribosomal RNA and secY indicated that these novel isolates belong to Leptospira alstonii, a unique pathogenic species of which only 7 isolates have been described to date. Earlier isolations were limited geographically to China, Japan and Malaysia, and this leptospiral species had not previously been cultured from mammals. Restriction enzyme analysis (REA) further confirms the novelty of these strains since no similar patterns were observed with a reference database of leptospires. As with other pathogenic Leptospira species, these isolates contain lipL32 and do not grow in the presence of 8-azagunaine; however no evidence of disease was apparent after experimental infection of hamsters. These isolates are genetically related to L. alstonii but have a novel REA pattern; they represent a new serovar which we designate as serovar Room22. This study demonstrates that invasive mammalian species act as bridge vectors of novel zoonotic pathogens such as Leptospira. PMID:27935961

  16. Emerging Infectious Disease Implications of Invasive Mammalian Species: The Greater White-Toothed Shrew (Crocidura russula) Is Associated With a Novel Serovar of Pathogenic Leptospira in Ireland.

    Science.gov (United States)

    Nally, Jarlath E; Arent, Zbigniew; Bayles, Darrell O; Hornsby, Richard L; Gilmore, Colm; Regan, Siobhan; McDevitt, Allan D; Yearsley, Jon; Fanning, Séamus; McMahon, Barry J

    2016-12-01

    The greater white-toothed shrew (Crocidura russula) is an invasive mammalian species that was first recorded in Ireland in 2007. It currently occupies an area of approximately 7,600 km2 on the island. C. russula is normally distributed in Northern Africa and Western Europe, and was previously absent from the British Isles. Whilst invasive species can have dramatic and rapid impacts on faunal and floral communities, they may also be carriers of pathogens facilitating disease transmission in potentially naive populations. Pathogenic leptospires are endemic in Ireland and a significant cause of human and animal disease. From 18 trapped C. russula, 3 isolates of Leptospira were cultured. However, typing of these isolates by standard serological reference methods was negative, and suggested an, as yet, unidentified serovar. Sequence analysis of 16S ribosomal RNA and secY indicated that these novel isolates belong to Leptospira alstonii, a unique pathogenic species of which only 7 isolates have been described to date. Earlier isolations were limited geographically to China, Japan and Malaysia, and this leptospiral species had not previously been cultured from mammals. Restriction enzyme analysis (REA) further confirms the novelty of these strains since no similar patterns were observed with a reference database of leptospires. As with other pathogenic Leptospira species, these isolates contain lipL32 and do not grow in the presence of 8-azagunaine; however no evidence of disease was apparent after experimental infection of hamsters. These isolates are genetically related to L. alstonii but have a novel REA pattern; they represent a new serovar which we designate as serovar Room22. This study demonstrates that invasive mammalian species act as bridge vectors of novel zoonotic pathogens such as Leptospira.

  17. Antibacterial activity of Green Seaweed Caulerpa racemosa from Takalar Waters against pathogenic bacteria promoting ice-ice diseases in the agar-producing red algae Gracilaria verrucosa.

    OpenAIRE

    Zainuddin, Elmi Nurhaidah; Anshary, Hilal; Huyyirnah; Hiola, Ridha

    2012-01-01

    The Ice-ice disease caused by bacterial pathogens which attack the algae tissue resulted white and brittle of seaweed thallus on red seaweed Gracilaria verrucosa farming. Study of antibacterial activity of green seaweed Caulerpa racemosa against the pathogens has been done using method include isolation of bacteria, pathogenicity test with Koch's postulates method, characterization of ice-ice bacteria, extraction of Caulerpa racemosa, and antibacterial test by agar diffusion method. The res...

  18. Factors Affecting Microbial Load and Profile of Potential Pathogens and Food Spoilage Bacteria from Household Kitchen Tables.

    Science.gov (United States)

    Biranjia-Hurdoyal, Susheela; Latouche, Melissa Cathleen

    2016-01-01

    The aim was to study the bacterial load and isolate potential pathogens and food spoilage bacteria from kitchen tables, including preparation tables and dining tables. Methods. A total of 53 households gave their consent for participation. The samples were collected by swabbing over an area of 5 cm by 5 cm of the tables and processed for bacterial count which was read as colony forming units (CFU), followed by isolation and identification of potential pathogens and food spoilage bacteria. Result. Knowledge about hygiene was not always put into practice. Coliforms, Enterococcus spp., Pseudomonas spp., Proteus spp., and S. aureus were detected from both dining and preparation tables. The mean CFU and presence of potential pathogens were significantly affected by the hygienic practices of the main food handler of the house, materials of kitchen tables, use of plastic covers, time of sample collection, use of multipurpose sponges/towels for cleaning, and the use of preparation tables as chopping boards (p Kitchen tables could be very important source of potential pathogens and food spoilage bacteria causing foodborne diseases. Lack of hygiene was confirmed by presence of coliforms, S. aureus, and Enterococcus spp. The use of plastic covers, multipurpose sponges, and towels should be discouraged.

  19. In vitro growth inhibition of intra root canal pathogenic microorganisms by Lactic Acid Bacteria, an Antibiosis method

    Directory of Open Access Journals (Sweden)

    A. Nakhjavani F.

    2008-12-01

    Full Text Available "nBackground and Aim: Elimination of microorganisms and their byproducts from root canal system is one of important aims of root canal therapy. This object is gained by using of many chemomechanical techniques but with noncertain success. A new method is used of nonpathogenic bacteria for growth inhibition of pathogenic bacteria, Antibiosis, in root canal therapy.The aim of this study was in vitro evaluation of antimicrobial effect of probiotics, such as Lactic Acid Bacteria (LAB on the infected root canal bacteria. "nMaterials and Methods: Isolated bacteria from infected root canal were grown and then scattered onto the muller Hinton agar plates which contain wells, LAB, extracted from dairy products, were added into these wells, Inhibition effected of LAB was determined. Furthermore the sample taken from the inhibition zone and possible resistant monoclonal bacteria also were identified, then 6 sensitive and 14 resistant samples were selected and E. faecalis species were added to them; Then antimicrobial effects of LAB on these samples was reevaluated. "nResults: The results showed that 66.7% of the samples were sensitive at least to one type of LAB, and 33% were resistant to all kind of LAB. Meanwhile the outgrowing anaerobic bacteria inside the inhibition zone were from the low frequency oral bacterial flora. Furthermore, adding E. faecalis to the samples caused more sensitivity of them to LAB. Mc-Neamar test recognized the difference significant. "nConclusion: This study showed that the LAB inhibit growth of the pathogenic root canal bacteriae. Furthermore, presence of E. faecalis reinforces the antimicrobial effect of LAB. It seemed that LAB maybe have potential to use in endodontic practice for elimination of root canal infections.

  20. Emerging role of bacteria in oral carcinogenesis: a review with special reference to perio-pathogenic bacteria

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    Manosha Perera

    2016-09-01

    Full Text Available Oral cancer, primarily oral squamous cell carcinoma (OSCC, continues to be a major global health problem with high incidence and low survival rates. While the major risk factors for this malignancy, mostly lifestyle related, have been identified, around 15% of oral cancer cases remain unexplained. In light of evidence implicating bacteria in the aetiology of some cancer types, several epidemiological studies have been conducted in the last decade, employing methodologies ranging from traditional culture techniques to 16S rRNA metagenomics, to assess the possible role of bacteria in OSCC. While these studies have demonstrated differences in microbial composition between cancerous and healthy tissues, they have failed to agree on specific bacteria or patterns of oral microbial dysbiosis to implicate in OSCC. On the contrary, some oral taxa, particularly Porphyromonas gingivalis and Fusobacterium nucleatum, show strong oral carcinogenic potential in vitro and in animal studies. Bacteria are thought to contribute to oral carcinogenesis via inhibition of apoptosis, activation of cell proliferation, promotion of cellular invasion, induction of chronic inflammation, and production of carcinogens. This narrative review provides a critical analysis of and an update on the association between bacteria and oral carcinogenesis and the possible mechanisms underlying it.

  1. Emerging role of bacteria in oral carcinogenesis: a review with special reference to perio-pathogenic bacteria

    Science.gov (United States)

    Perera, Manosha; Al-hebshi, Nezar Noor; Speicher, David J.; Perera, Irosha; Johnson, Newell W.

    2016-01-01

    Oral cancer, primarily oral squamous cell carcinoma (OSCC), continues to be a major global health problem with high incidence and low survival rates. While the major risk factors for this malignancy, mostly lifestyle related, have been identified, around 15% of oral cancer cases remain unexplained. In light of evidence implicating bacteria in the aetiology of some cancer types, several epidemiological studies have been conducted in the last decade, employing methodologies ranging from traditional culture techniques to 16S rRNA metagenomics, to assess the possible role of bacteria in OSCC. While these studies have demonstrated differences in microbial composition between cancerous and healthy tissues, they have failed to agree on specific bacteria or patterns of oral microbial dysbiosis to implicate in OSCC. On the contrary, some oral taxa, particularly Porphyromonas gingivalis and Fusobacterium nucleatum, show strong oral carcinogenic potential in vitro and in animal studies. Bacteria are thought to contribute to oral carcinogenesis via inhibition of apoptosis, activation of cell proliferation, promotion of cellular invasion, induction of chronic inflammation, and production of carcinogens. This narrative review provides a critical analysis of and an update on the association between bacteria and oral carcinogenesis and the possible mechanisms underlying it. PMID:27677454

  2. The inhibitory effect of Thymus vulgaris extracts on the planktonic form and biofilm structures of six human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Zinab Mohsenipour

    2015-06-01

    Full Text Available Objective: Microorganisms are responsible for many problems in industry and medicine because of biofilm formation. Therefore, this study was aimed to examine the effect of Thymus vulgaris (T. vulgaris extracts on the planktonic form and biofilm structures of six pathogenic bacteria. Materials and methods: Antimicrobial activities of the plant extracts against the planktonic form of the bacteria were determined using the disc diffusion method. MIC and MBC values were evaluated using macrobroth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. Results: According to disc diffusion test (MIC and MBC, the ability of Thymus vulgaris (T. vulgaris extracts for inhibition of bacteria in planktonic form was confirmed. In dealing with biofilm structures, the inhibitory effect of the extracts was directly correlated to their concentration. Except for the inhibition of biofilm formation, efficacy of each extract was independent from type of solvent. Conclusion: According to the potential of Thymus vulgaris (T. vulgaris extracts to inhibit the test bacteria in planktonic and biofilm form, it can be suggested that Thymus vulgaris(T. vulgaris extracts can be applied as antimicrobial agents against the pathogenic bacteria particularly in biofilm forms.

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

    Science.gov (United States)

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

    2005-11-28

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

  4. 1,3-Propanediol production by new recombinant Escherichia coli containing genes from pathogenic bacteria.

    Science.gov (United States)

    Przystałowska, Hanna; Zeyland, Joanna; Szymanowska-Powałowska, Daria; Szalata, Marlena; Słomski, Ryszard; Lipiński, Daniel

    2015-02-01

    1,3-Propanediol (1,3-PDO) is an organic compound, which is a valuable intermediate product, widely used as a monomer for synthesizing biodegradable polymers, increasing their strength; as well as an ingredient of textile, cosmetic and medical products. 1,3-PDO is mostly synthesized chemically. Global companies have developed technologies for 1,3-PDO synthesis from petroleum products such as acrolein and ethylene oxide. A potentially viable alternative is offered by biotechnological processes using microorganisms capable of synthesizing 1,3-PDO from renewable substrates (waste glycerol, a by-product of biofuel production, or glucose). In the present study, genes from Citrobacter freundii and Klebsiella pneumoniae were introduced into Escherichia coli bacteria to enable the synthesis of 1,3-PDO from waste glycerol. These strains belong to the best 1,3-PDO producers, but they are pathogenic, which restricts their application in industrial processes. The present study involved the construction of two gene expression constructs, containing a total of six heterologous glycerol catabolism pathway genes from C. freundii ATCC 8090 and K. pneumoniae ATCC 700721. Heterologous genes encoding glycerol dehydratase (dhaBCE) and the glycerol dehydratase reactivation factor (dhaF, dhaG) from C. freundii and gene encoding 1,3-PDO oxidoreductase (dhaT) from K. pneumoniae were expressed in E. coli under the control of the T7lac promoter. An RT-PCR analysis and overexpression confirmed that 1,3-PDO synthesis pathway genes were expressed on the RNA and protein levels. In batch fermentation, recombinant E. coli bacteria used 32.6gl(-1) of glycerol to produce 10.6 gl(-1) of 1,3-PDO, attaining the efficiency of 0.4 (mol₁,₃-PDO molglycerol(-1)). The recombinant E. coli created is capable of metabolizing glycerol to produce 1,3-PDO, and the efficiency achieved provides a significant research potential of the bacterium. In the face of shortage of fossil fuel supplies and climate warming

  5. Associations between pathogens in the upper respiratory tract of young children: interplay between viruses and bacteria.

    Science.gov (United States)

    van den Bergh, Menno R; Biesbroek, Giske; Rossen, John W A; de Steenhuijsen Piters, Wouter A A; Bosch, Astrid A T M; van Gils, Elske J M; Wang, Xinhui; Boonacker, Chantal W B; Veenhoven, Reinier H; Bruin, Jacob P; Bogaert, Debby; Sanders, Elisabeth A M

    2012-01-01

    High rates of potentially pathogenic bacteria and respiratory viruses can be detected in the upper respiratory tract of healthy children. Investigating presence of and associations between these pathogens in healthy individuals is still a rather unexplored field of research, but may have implications for interpreting findings during disease. We selected 986 nasopharyngeal samples from 433 6- to 24-month-old healthy children that had participated in a randomized controlled trial. We determined the presence of 20 common respiratory viruses using real-time PCR. Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus were identified by conventional culture methods. Information on risk factors was obtained by questionnaires. We performed multivariate logistic regression analyses followed by partial correlation analysis to identify the overall pattern of associations. S. pneumoniae colonization was positively associated with the presence of H. influenzae (adjusted odds ratio 1.60, 95% confidence interval 1.18-2.16), M. catarrhalis (1.78, 1.29-2.47), human rhinoviruses (1.63, 1.19-2.22) and enteroviruses (1.97, 1.26-3.10), and negatively associated with S. aureus presence (0.59, 0.35-0.98). H. influenzae was positively associated with human rhinoviruses (1.63, 1.22-2.18) and respiratory syncytial viruses (2.78, 1.06-7.28). M. catarrhalis colonization was positively associated with coronaviruses (1.99, 1.01-3.93) and adenoviruses (3.69, 1.29-10.56), and negatively with S. aureus carriage (0.42, 0.25-0.69). We observed a strong positive association between S. aureus and influenza viruses (4.87, 1.59-14.89). In addition, human rhinoviruses and enteroviruses were positively correlated (2.40, 1.66-3.47), as were enteroviruses and human bocavirus, WU polyomavirus, parainfluenza viruses, and human parechovirus. A negative association was observed between human rhinoviruses and coronaviruses. Our data revealed high viral and bacterial

  6. Inhibitory Effects of Gallic Acid Isolated from Caesalpinia mimosoides Lamk on Cholangiocarcinoma Cell Lines and Foodborne Pathogenic Bacteria.

    Science.gov (United States)

    Rattanata, Narintorn; Klaynongsruang, Sompong; Daduang, Sakda; Tavichakorntrakool, Ratree; Limpaiboon, Temduang; Lekphrom, Ratsami; Boonsiri, Patcharee; Daduang, Jureerut

    2016-01-01

    Gallic acid was isolated from Caesalpinia mimosoides Lamk and the structure s identified based on spectroscopic analysis and comparison with authentic compound. In this study we compared the ability of natural gallic acid (nGA) and commercial gallic acid (cGA) to inhibit the proliferation of cholangiocarcinoma cell lines (M213, M214) and foodborne pathogenic bacteria (Salmonella spp. and Plesiomonas shigelloides). Both nGA and cGA had the same inhibitory effects on cell proliferation by inducing apoptosis of cholangiocarcinoma cell lines. In addition, nGA inhibited growth of foodborne pathogenic bacteria in the same manner as cGA. Our results suggest that nGA from Caesalpinia mimosoides Lamk is a potential anticancer and antibacterial compound. However, in vivo studies are needed to elucidate the specific mechanisms involved.

  7. Perception of pathogenic or beneficial bacteria and their evasion of host immunity: pattern recognition receptors in the frontline.

    Directory of Open Access Journals (Sweden)

    Lucie eTrda

    2015-04-01

    Full Text Available Plants are continuously monitoring the presence of microorganisms to establish an adapted response. Plants commonly use pattern recognition receptors (PRRs to perceive microbe- or pathogen-associated molecular patterns (MAMPs/PAMPs which are microorganism molecular signatures. Located at the plant plasma membrane, the PRRs are generally receptor-like kinases (RLKs or receptor-like proteins (RLPs. MAMP detection will lead to the establishment of a plant defense program called MAMP-triggered immunity (MTI. In this review, we overview the RLKs and RLPs that assure early recognition and control of pathogenic or beneficial bacteria. We also highlight the crucial function of PRRs during plant-microbe interactions, with a special emphasis on the receptors of the bacterial flagellin and peptidoglycan. In addition, we discuss the multiple strategies used by bacteria to evade PRR-mediated recognition.

  8. Nasogastric feeding tubes from a neonatal department yield high concentrations of potentially pathogenic bacteria- even 1 d after insertion

    DEFF Research Database (Denmark)

    Petersen, Sandra Meinich; Greisen, Gorm; Krogfelt, Karen Angeliki

    2016-01-01

    probiotic administration through the tube. RESULTS: Out of the 94 NG-tubes, 89% yielded more than 1,000 colony-forming units (CFU)/ml bacteria, and 55% yielded the potentially pathogenic Enterobacteriaceae and/or Staphylococcus aureus. The mean concentration in the yield was 5.3 (SD: 2.1, maximum 9.4) log10......BACKGROUND: Preterm infants are vulnerable to pathogens and at risk of developing necrotizing enterocolitis (NEC) or sepsis. Nasogastric feeding tubes (NG-tubes) might contaminate feeds given through them due to biofilm formation. We wanted to determine if there is a rationale in replacing NG-tubes...... more often to reduce contamination. METHODS: We conducted an observational study of used NG-tubes from a tertiary neonatal department. After removal, we flushed a 1-ml saline solution through the tube, determined the density of bacteria by culture, and related it to the duration of use and any...

  9. Detection and characterization of foodborne pathogenic bacteria with hyperspectral microscope imaging

    Science.gov (United States)

    Rapid detection and identification of pathogenic microorganisms naturally occurring during food processing are important in developing intervention and verification strategies. In the poultry industry, contamination of poultry meat with foodborne pathogens (especially, Salmonella and Campylobacter) ...

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

    NARCIS (Netherlands)

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

    2014-01-01

    Intracellular bacterial pathogens have evolved distinct lifestyles inside eukaryotic cells. Some pathogens coexist with the infected cell in an obligate intracellular state, whereas others transit between the extracellular and intracellular environment. Adaptation to these intracellular lifestyles i

  11. Antibacterial activity of some medicinal mangroves against antibiotic resistant pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Abeysinghe P

    2010-01-01

    Full Text Available The antibacterial activity of the leaves and bark of mangrove plants, Avicennia marina, A. officinalis, Bruguiera sexangula, Exoecaria agallocha, Lumnitzera racemosa, and Rhizophora apiculata was evaluated against antibiotic resistant pathogenic bacteria, Staphylococcus aureus and Proteus sp. Soxhlet extracts of petroleum ether, ethyl acetate, ethanol and water were prepared and evaluated the antibacterial activity using agar diffusion method. Most of the plant extracts showed promising antibacterial activity against both bacterial species. However, higher antibacterial activity was observed for Staphylococcus aureus than Proteus sp. The highest antibacterial activity was shown by ethyl acetate of mature leaf extracts of E. agallocha for Staphylococcus aureus. All ethyl acetate extracts showed higher inhibition against S. aureus while some extracts of chloroform, ethyl acetate and ethanol gave inhibition against Proteus sp. None of the petroleum ether and aqueous extracts showed inhibition against Proteus sp. All fresh plant materials did also show more antibacterial activity against both bacterial strains than did dried plant extracts. Antibacterial activity of fresh and dried plant materials reduced for both bacterial strains with time after extraction. Since L. racemosa and A. marina gave the best inhibition for bacterial species, they were used for further investigations. Charcoal treated plant extracts of L. racemosa and A. marina were able to inhibit both bacterial strains more than those of untreated plant extracts. Phytochemical screening of mature leaf, bark of L. racemosa and leaf extracts of A. marina has been carried out and revealed that leaf and bark contained alkaloids, steroids, triterpenoids and flavonoids. None of the above extracts indicate the presence of saponins and cardiac glycosides. Separated bands of extracts by TLC analysis showed antibacterial activity against S. aureus.

  12. THE IMMUNOLOGICAL STRUCTURE OF POPULATION OF KARAKUL LAMBS BUCCINATED AGAINST CONDITIONALLY AND ACUTE PATHOGENOUS BACTERIA

    Directory of Open Access Journals (Sweden)

    Rachmatullo Ruzikulov

    2014-12-01

    Full Text Available Antibodies, developing in animal and human organisms against antigens of external and internal origin are not limited with opsonization functions, lying on the base of formation of humoral immunity. Being the product of somatic mutations of plasmatic cells, according to clonal selection theory of immunity, they themselves are also alien proteins for organisms. Thus, they themselves also begin to display antigen pressure on the immune competent system. So, they will start themselves the elaboration of antibodies against them, which are called anti–idiotypic ones. Anti–idiotypic antibodies, imitating the corresponding bacterial and virus antigens are able to initiate the immune response of animal organism against them, which play great immune modulating role. The immunological structure of populations of Karakul sheep lambs vaccinated against E. coli bacteria, salmonellosis and anthrax antigen from the age of 2–3 days till 2–3 weeks was studied. Experiments were carried out in the 1–2, 3–4, 5–6, 7–8, 9–10 and 11–12 weeks old Karakul lambs. Experimental lambs during appraisal were vaccinated once by associated hydroxide aluminum form vaccine against paratyphoid and coli bacteriosis of calves, pigs and lambs. In another experiment, the lambs were immunized by rare naturally occurring bacterial antigen. As such an immunogenic was selected sterile soluble anthrax antigen. Developed and tested in the application of Ascoli reaction the role of anti–idiotype antibodies in the formation of natural immunity against opportunistic pathogens identified the nature of normal antibodies was studied. The nature of wavelike character of the immune reaction of an organism of newborn animals of vaccination was revealed. Also the immunomodulation role of anti–idiotypic antibodies was determined.

  13. Suppression of Emergence of Resistance in Pathogenic Bacteria: Keeping Our Powder Dry, Part 1.

    Science.gov (United States)

    Drusano, G L; Louie, Arnold; MacGowan, Alasdair; Hope, William

    2015-12-28

    We are in a crisis of bacterial resistance. For economic reasons, most pharmaceutical companies are abandoning antimicrobial discovery efforts, while, in health care itself, infection control and antibiotic stewardship programs have generally failed to prevent the spread of drug-resistant bacteria. At this point, what can be done? The first step has been taken. Governments and international bodies have declared there is a worldwide crisis in antibiotic drug resistance. As discovery efforts begin anew, what more can be done to protect newly developing agents and improve the use of new drugs to suppress resistance emergence? A neglected path has been the use of recent knowledge regarding antibiotic dosing as single agents and in combination to minimize resistance emergence, while also providing sufficient early bacterial kill. In this review, we look at the data for resistance suppression. Approaches include increasing the intensity of therapy to suppress resistant subpopulations; developing concepts of clinical breakpoints to include issues surrounding suppression of resistance; and paying attention to the duration of therapy, which is another important issue for resistance suppression. New understanding of optimizing combination therapy is of interest for difficult-to-treat pathogens like Pseudomonas aeruginosa, Acinetobacter spp., and multidrug-resistant (MDR) Enterobacteriaceae. These lessons need to be applied to our old drugs to preserve them as well and need to be put into national and international antibiotic resistance strategies. As importantly, from a regulatory perspective, new chemical entities should have a corresponding resistance suppression plan at the time of regulatory review. In this way, we can make the best of our current situation and improve future prospects.

  14. 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.

  15. Antimicrobial activities of chicken β -defensin (4 and 10 peptides against pathogenic bacteria and fungi

    Directory of Open Access Journals (Sweden)

    Haitham Ahmed Yacoub

    2015-04-01

    Full Text Available Host Defense Peptides (HDPs are small cationic peptides found in several organisms. They play a vital role in innate immunity response and immunomodulatory stimulation. This investigation was designed to study the antimicrobial activities of β-defensin peptide-4 (sAvBD-4 and 10 (sAvBD-4 derived from chickens against pathogenic organisms including bacteria and fungi. Ten bacterial strains and three fungal species were used in investigation. The results showed that the sAvBD-10 displayed a higher bactericidal potency against all the tested bacterial strains than that of sAvBD-4. The exhibited bactericidal activity was significant against almost the different bacterial strains at different peptide concentrations except for that of P. aeruginosa and Str. bovis strains where a moderate effect was noted. Both peptides were effective in the inactivation of fungal species tested yielding a killing rate of up to 95%. The results revealed that the synthetic peptides were resistant to salt at a concentration of 50mM NaCl. However, they lost antimicrobial potency when applied in the presence of high salt concentrations. Based on blood hemolysis studies, a little hemolytic effect was showed in the case of both peptides even when applied at high concentrations. The data obtained from this study indicated that synthetic avian peptides exhibit strong antibacterial and antifungal activity. In conclusion, future work and research should be tailored to a better understanding of the mechanisms of action of those peptides and their potential use in the pharmaceutical industry to help reduce the incidence and impact of infectious agent and be marketed as a naturally occurring antibiotic.

  16. Antifungal Activity of Lactic Acid Bacteria Strains Isolated from Natural Honey against Pathogenic Candida Species

    Science.gov (United States)

    Bulgasem, Bulgasem Y.; Lani, Mohd Nizam; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G.

    2016-01-01

    The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species. PMID:28154488

  17. Antimicrobial activities of chicken β-defensin (4 and 10) peptides against pathogenic bacteria and fungi.

    Science.gov (United States)

    Yacoub, Haitham A; Elazzazy, Ahmed M; Abuzinadah, Osama A H; Al-Hejin, Ahmed M; Mahmoud, Maged M; Harakeh, Steve M

    2015-01-01

    Host Defense Peptides (HDPs) are small cationic peptides found in several organisms. They play a vital role in innate immunity response and immunomodulatory stimulation. This investigation was designed to study the antimicrobial activities of β-defensin peptide-4 (sAvBD-4) and 10 (sAvBD-4) derived from chickens against pathogenic organisms including bacteria and fungi. Ten bacterial strains and three fungal species were used in investigation. The results showed that the sAvBD-10 displayed a higher bactericidal potency against all the tested bacterial strains than that of sAvBD-4. The exhibited bactericidal activity was significant against almost the different bacterial strains at different peptide concentrations except for that of Pseudomonas aeruginosa (P. aeruginosa) and Streptococcus bovis (Str. bovis) strains where a moderate effect was noted. Both peptides were effective in the inactivation of fungal species tested yielding a killing rate of up to 95%. The results revealed that the synthetic peptides were resistant to salt at a concentration of 50 mM NaCl. However, they lost antimicrobial potency when applied in the presence of high salt concentrations. Based on blood hemolysis studies, a little hemolytic effect was showed in the case of both peptides even when applied at high concentrations. The data obtained from this study indicated that synthetic avian peptides exhibit strong antibacterial and antifungal activity. In conclusion, future work and research should be tailored to a better understanding of the mechanisms of action of those peptides and their potential use in the pharmaceutical industry to help reduce the incidence and impact of infectious agent and be marketed as a naturally occurring antibiotic.

  18. Mechanisms of infection by pathogens transmitted by ticks on the example of bacteria: Anaplasma phagocytophilum and Borrelia burgdorferi

    OpenAIRE

    2016-01-01

    Tick-borne diseases are transmission diseases belonging to the group of zoonoses but carried by ticks. These diseases are a major public health problem but also a problem for groups occupationally exposed to tick bites. Ixodes ricinus is a species of ticks which is the most common reservoir and the vector of a large number of microorganisms pathogenic to humans. It transfers, among others, bacteria of the species: Anaplasma phagocytophilum and Borrelia burgdorferi. The...

  19. The Wnt/β-Catenin Signaling Pathway Controls the Inflammatory Response in Infections Caused by Pathogenic Bacteria

    OpenAIRE

    Octavio Silva-García; Valdez-Alarcón, Juan J.; Baizabal-Aguirre, Víctor M.

    2014-01-01

    Innate immunity against pathogenic bacteria is critical to protect host cells from invasion and infection as well as to develop an appropriate adaptive immune response. During bacterial infection, different signaling transduction pathways control the expression of a wide range of genes that orchestrate a number of molecular and cellular events to eliminate the invading microorganisms and regulate inflammation. The inflammatory response must be tightly regulated because uncontrolled inflammati...

  20. A system for detection and identification of foodborne pathogenic bacteria based on a “Combinatory qPCR” technology

    OpenAIRE

    2014-01-01

    Foodborne outbreaks are important issues worldwide. Two of the most important foodborne pathogens are Salmonella spp. and Listeria monocytogenes. The reference methods to detect foodborne bacteria are international standard operating procedures, ISO methods, which are recognized in the whole world. These methods are mostly culture-based methods that are time consuming (several days) and labor intensive. In order to identify faster the source of foodborne outbreaks, to better manage food-relat...

  1. Genome comparison of the epiphytic bacteria Erwinia billingiae and E. tasmaniensis with the pear pathogen E. pyrifoliae

    Directory of Open Access Journals (Sweden)

    Kuhl Heiner

    2010-06-01

    Full Text Available Abstract Background The genus Erwinia includes plant-associated pathogenic and non-pathogenic Enterobacteria. Important pathogens such as Erwinia amylovora, the causative agent of fire blight and E. pyrifoliae causing bacterial shoot blight of pear in Asia belong to this genus. The species E. tasmaniensis and E. billingiae are epiphytic bacteria and may represent antagonists for biocontrol of fire blight. The presence of genes that are putatively involved in virulence in E. amylovora and E. pyrifoliae is of special interest for these species in consequence. Results Here we provide the complete genome sequences of the pathogenic E. pyrifoliae strain Ep1/96 with a size of 4.1 Mb and of the non-pathogenic species E. billingiae strain Eb661 with a size of 5.4 Mb, de novo determined by conventional Sanger sequencing and next generation sequencing techniques. Genome comparison reveals large inversions resulting from homologous recombination events. Furthermore, comparison of deduced proteins highlights a relation of E. billingiae strain Eb661 to E. tasmaniensis strain Et1/99 and a distance to E. pyrifoliae for the overall gene content as well as for the presence of encoded proteins representing virulence factors for the pathogenic species. Pathogenicity of E. pyrifoliae is supposed to have evolved by accumulation of potential virulence factors. E. pyrifoliae carries factors for type III secretion and cell invasion. Other genes described as virulence factors for E. amylovora are involved in the production of exopolysaccharides, the utilization of plant metabolites such as sorbitol and sucrose. Some virulence-associated genes of the pathogenic species are present in E. tasmaniensis but mostly absent in E. billingiae. Conclusion The data of the genome analyses correspond to the pathogenic lifestyle of E. pyrifoliae and underlines the epiphytic localization of E. tasmaniensis and E. billingiae as a saprophyte.

  2. An antibody microarray, in multiwell plate format, for multiplex screening of foodborne pathogenic bacteria and biomolecules

    Science.gov (United States)

    Intoxication and infection caused by foodborne pathogens are important problems in the United States, and screening tests for multiple pathogen detection have been developed because food producers are known reservoirs of multiple pathogens. We developed a 96-well microplate, multiplex antibody micr...

  3. PENAMBAHAN BAKTERI ASAM LAKTAT TERENKAPSULASI UNTUK MENEKAN PERTUMBUHAN BAKTERI PATOGEN PADA PROSES PRODUKSI TAPIOKA [Addition of Encapsulated Lactic Acid Bacteria to Suppress the Growth of Pathogenic Bacteria during Tapioca Production

    Directory of Open Access Journals (Sweden)

    Glisina Dwinoor Rembulan

    2015-07-01

    Full Text Available Lactic acid bacteria (LAB produce organic acids and active compounds which can inhibit the growth of pathogenic bacteria. Lactic acid bacteria potentially can be introduced to inhibit pathogenic bacteria in the tapioca production at the extraction stage, especially during the settling process since there is possibility of starch slurry to be contaminated by pathogenic bacteria from water. The objectives of this research were to design a solid starter of LAB through encapsulation by using modified starch includes sour cassava starch, lintnerized cassava starch and nanocrystalline starch, utilize the starter for suppressing the growth of pathogenic bacteria in the production process of tapioca and characterize the functional properties of tapioca. The encapsulation of lactic acid bacteria was conducted by freeze drying at a temperature of -50°C for 48 hours. The viability of LAB after freeze drying with sour cassava starch matrix was 92% of the liquid starter, with lintnerized cassava starch matrix was 93%, while that with nanocrystalline matrix was 96%. After application of the LAB culture during settling process for tapioca extraction and the tapioca was stored at room temperature for 6 months, it was shown that E. coli, Salmonella and Shigella were  detected in the native tapioca starch (without treatment while the starch added with lactic acid bacteria starter was not absent for the pathogenic bacteria. The addition of lactic acid bacteria in extraction process can suppress the growth of pathogenic bacteria in tapioca. The results showed that lintnerized cassava starch matrix is the best matrix because after 6 months it still contained lactic acid bacteria as compared to liquid starter and that encapsulated with other matrixes.

  4. ntibacterial and brine shrimp lethality effect of marine actinobacterium Streptomyces sp. CAS72 against human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Palaniappan Sivasankar

    2013-08-01

    Full Text Available Objective: To investigate the in vitro antibacterial activity against human pathogenic bacteria and brine shrimp lethality bioassay of the marine actinobacterium. Methods: Forty six marine actinobacterial strains were isolated from sediment samples of Uppanar estuary, Cuddalore, India. Preliminary screening was done by cross-streak method and the potential strain was identified by morphological, chemotaxonomical and molecular methods. Fermentation was done and the metabolite was obtained by liquid-liquid extraction using ethyl acetate and purified by silica gel (100-200 mesh column chromatography. The purified metabolite was tested for antibacterial activity, minimal inhibitory concentration and brine shrimp lethality bioassay. Results: Among the forty six strains, CAS72 was found effective against human pathogenic bacteria. The strain CAS72 was identified as Streptomyces sp. The purified metabolite exhibited a significant in vitro antibacterial activity. The MIC value was also determined against human pathogenic bacteria and a strong cytotoxic activity in brine shrimp lethality assay was observed and the LC 50 value was 23.5 µg/mL. Conclusions: The present investigation reveals that the marine actinobacteria are well obtainable in Uppanar estuary environment and it can provide a definite source for novel bioactive metabolites.

  5. INACTIVATION OF PATHOGENIC BACTERIA USING PULSED UV-LIGHT AND ITS APPLICATION IN WATER DISINFECTION AND QUALITY CONTROL

    Directory of Open Access Journals (Sweden)

    M. K. Sharifi-Yazdi H. Darghahi

    2006-09-01

    Full Text Available The lethality of pulsed ultra-violet (UV rich light for the inactivation of pathogenic bacteria has been investigated. A low pressure xenon filled flash lamps that produced UV intensities have been used. The pulsed operation of the system enable the release of electrical energy stored in the capacitor into the flash lamp within a short time and produces the high current and high peak power required for emitting the intense UV flash. The flash frequency was adjusted to one pulse per second. Several types of bacteria were investigated for their susceptibility to pulsed UV illumination. The treated bacterial populations were reduced and determined by direct viable counts. Among the tested bacteria Pseudomonas aeruginosa was the most susceptible to the pulsed UV- light with a 8 log10 cfu/ml reduction after 11 pulses, while the spores of Bacillus megaterium was the most resistant and only 4 log10 cfu/ml reduction achieved after 50 pulses of illumination. The results of this study demonstrated that pulsed UV- light technology could be used as an effective method for the inactivation, of pathogenic bacteria in different environments such as drinking water.

  6. Functional Fe3O4/TiO2 core/shell magnetic nanoparticles as photokilling agents for pathogenic bacteria.

    Science.gov (United States)

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

    2008-04-01

    A photokilling approach for pathogenic bacteria is demonstrated using a new type of magnetic nanoprobe as the photokilling agent. In addition to their magnetic property, the nanoprobes have other features including a photocatalytic property and the capacity to target bacteria. The nanoprobes comprise iron oxide/titania (Fe(3)O(4)@TiO(2)) core/shell magnetic nanoparticles. As dopamine molecules can self-assemble onto the surface of the titania substrate, dopamine is used as the linker to immobilize succinic anhydride onto the surfaces of the Fe(3)O(4)@TiO(2) nanoparticles. This is followed by the immobilization of IgG via amide bonding. We demonstrate that the IgG-Fe(3)O(4)@TiO(2) magnetic nanoparticles not only have the capacity to target several pathogenic bacteria, but they also can effectively inhibit the cell growth of the bacteria targeted by the nanoparticles under irradiation of a low-power UV lamp within a short period. Staphylococcus saprophyticus, Streptococcus pyogenes, and antibiotic-resistant bacterial strains, such as multiantibiotic-resistant S. pyogenes and methicillin-resistant Staphylococcus aureus (MRSA), are used to demonstrate the feasibility of this approach.

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

    Science.gov (United States)

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

    2011-07-01

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

  8. Rapid Identification of Pathogenic Bacteria by means of Two Conservative Gene Loci' Specific PCR-CE-RFLP

    Institute of Scientific and Technical Information of China (English)

    高鹏; 张卓然; 徐维家; 安万新; 张晓慧; 戴兵; 范艳萍; 王运锋; 李萍; 温杰; 于卫健; 高向仪; 谢凡迪; 王永海

    2003-01-01

    To establish a rapid identification method for common pathogenic bacteria on the basis of molecular biology and to construct a preliminary Polymerase Chain Reaction-Capillary Electrophoresis-Restriction Fragment Length Polymorphism (PCR-CE-RFLP) database of bacteria isolated from clinical specimens frequently, 183 strains collected from clinical samples belonging to 12 genera and 19 species whose biochemical characterizations corresponded to the typical ones were examined.The genomic DNAs were amplified by two pairs of fluorescence labeled primers aiming at 16S rRNA gene and 16S-23S rRNA spacer region gene respectively at the same time. PCR products were then digested by restriction endonuclease Hae Ⅲ in-completely before taking capillary electrophoresis. The results with the PCR-CE-RFLP patterns of 16S rRNA genes were just alike within some genera, but when it comes to 16S-23S rRNA spacer region genes, each bacterium showed a unique pattern, which can be distinguished from each other easily. It seems that PCR-CE-RFLP patterns of 16S rRNA gene could only be used to classify the bacteria into family level, whereas the data of 16S-23S rRNA spacer region gene could be utilized to identify the whole microorganisms as precisely as the species level. In spite of the data of the spacer region gene alone can be sufficiently to verify the whole bacteria, we insist that the 16S rRNA gene could be of some assistant in case that there should be lots of families of bacteria, in which some similar ones, with the same RFLP data of 16S-23S rRNA spacer region gene, may coexist. This study proves that the utility of PCR-CE-RFLP is a convenient, rapid method to identify pathogenic bacteria, and is also a quick diagnosis measure for application to clinical use.

  9. Cockroaches (Periplaneta americana and Blattella germanica) as potential vectors of the pathogenic bacteria found in nosocomial infections.

    Science.gov (United States)

    Fakoorziba, M R; Eghbal, F; Hassanzadeh, J; Moemenbellah-Fard, M D

    2010-09-01

    Although it has been difficult to prove the direct involvement of cockroaches (i.e. insects of the order Blattaria) in the transmission of pathogenic agents to humans, such insects often carry microorganisms that are important in nosocomial infections, and their medical importance in the spread of bacteria cannot be ruled out. In houses and institutions with poor standards of hygiene, heavy infestations with cockroaches, such as the peridomestic American cockroach (Periplaneta americana L.) and the domestic German cockroach (Blattella germanica L.), can occur. In the present study, cockroaches (126 B. germanica and 69 P. americana) were collected from four buildings (three public training hospitals and one house) in central Tehran, Iran. Each insect was processed, under sterile conditions, so that the bacteria on its external surfaces and in its alimentary tract and faecal pellets could be isolated and identified. The oldest and largest of the three hospitals sampled (a 1400-bed unit built 80 years ago) appeared to be the one most heavily infested with cockroaches, and cockroaches from this hospital accounted for most (65.4%) of the isolates of medically important bacteria made during the study. No significant difference was found between the percentages of P. americana and B. germanica carrying medically important bacteria (96.8% v. 93.6%; P>0.05). At least 25 different species of medically important bacteria were isolated and identified, and at least 22 were Gramnegative. The genus of enteric bacteria most frequently isolated from both cockroach species, at all four collection sites, was Klebsiella. The cockroaches from each hospital were much more likely to be found contaminated with medically important bacteria than those from the house. The hospital cockroaches were also more likely to be carrying medically important bacteria internally than externally (84.3% v. 64.1%; Pcockroaches and nosocomial infections, are discussed.

  10. Combined antibacterial activity of stingless bee (Apis mellipodae) honey and garlic (Allium sativum) extracts against standard and clinical pathogenic bacteria

    Institute of Scientific and Technical Information of China (English)

    Berhanu Andualem

    2013-01-01

    Objective:To investigate the synergic antibacterial activity of garlic and tazma honey against standard and clinical pathogenic bacteria. Methods:Antimicrobial activity of tazma honey, garlic and mixture of them against pathogenic bacteria were determined. Chloramphenicol and water were used as positive and negative controls, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration of antimicrobial samples were determined using standard methods. Results: Inhibition zone of mixture of garlic and tazma honey against all tested pathogens was significantly (P≤0.05) greater than garlic and tazma honey alone. The diameter zone of inhibition ranged from (18±1) to (35±1) mm for mixture of garlic and tazma honey, (12±1) to (20±1) mm for tazma honey and (14±1) to (22±1) mm for garlic as compared with (10±1) to (30±1) mm for chloramphenicol. The combination of garlic and tazma honey (30-35 mm) was more significantly (P≤0.05) effective against Salmonella (NCTC 8385), Staphylococcus aureus (ATCC 25923), Lyesria moncytogenes (ATCC 19116) and Streptococcus pneumonia (ATCC 63). Results also showed considerable antimicrobial activity of garlic and tazma honey. MIC of mixture of garlic and tazma honey at 6.25%against total test bacteria was 88.9%. MIC of mixture of garlic and tazma honey at 6.25%against Gram positive and negative were 100%and 83.33%, respectively. The bactericidal activities of garlic, tazma honey, and mixture of garlic and tazma honey against all pathogenic bacteria at 6.25%concentration were 66.6%, 55.6%and 55.6%, respectively. Conclusions: This finding strongly supports the claim of the local community to use the combination of tazma honey and garlic for the treatment of different pathogenic bacterial infections. Therefore, garlic in combination with tazma honey can serve as an alternative natural antimicrobial drug for the treatment of pathogenic bacterial infections. Further in vivo study is recommended to come up

  11. Cost-Effective Filter Materials Coated with Silver Nanoparticles for the Removal of Pathogenic Bacteria in Groundwater

    Science.gov (United States)

    Mpenyana-Monyatsi, Lizzy; Mthombeni, Nomcebo H.; Onyango, Maurice S.; Momba, Maggy N. B.

    2012-01-01

    The contamination of groundwater sources by pathogenic bacteria poses a public health concern to communities who depend totally on this water supply. In the present study, potentially low-cost filter materials coated with silver nanoparticles were developed for the disinfection of groundwater. Silver nanoparticles were deposited on zeolite, sand, fibreglass, anion and cation resin substrates in various concentrations (0.01 mM, 0.03 mM, 0.05 mM and 0.1 mM) of AgNO3. These substrates were characterised by SEM, EDS, TEM, particle size distribution and XRD analyses. In the first phase, the five substrates coated with various concentrations of AgNO3 were tested against E. coli spiked in synthetic water to determine the best loading concentration that could remove pathogenic bacteria completely from test water. The results revealed that all filters were able to decrease the concentration of E. coli from synthetic water, with a higher removal efficiency achieved at 0.1 mM (21–100%) and a lower efficiency at 0.01 mM (7–50%) concentrations. The cation resin-silver nanoparticle filter was found to remove this pathogenic bacterium at the highest rate, namely 100%. In the second phase, only the best performing concentration of 0.1 mM was considered and tested against presumptive E. coli, S. typhimurium, S. dysenteriae and V. cholerae from groundwater. The results revealed the highest bacteria removal efficiency by the Ag/cation resin filter with complete (100%) removal of all targeted bacteria and the lowest by the Ag/zeolite filter with an 8% to 67% removal rate. This study therefore suggests that the filter system with Ag/cation resin substrate can be used as a potential alternative cost-effective filter for the disinfection of groundwater and production of safe drinking water. PMID:22470290

  12. Modulation of pathogen-induced CCL20 secretion from HT-29 human intestinal epithelial cells by commensal bacteria.

    LENUS (Irish Health Repository)

    Sibartie, Shomik

    2009-01-01

    BACKGROUND: Human intestinal epithelial cells (IECs) secrete the chemokine CCL20 in response to infection by various enteropathogenic bacteria or exposure to bacterial flagellin. CCL20 recruits immature dendritic cells and lymphocytes to target sites. Here we investigated IEC responses to various pathogenic and commensal bacteria as well as the modulatory effects of commensal bacteria on pathogen-induced CCL20 secretion. HT-29 human IECs were incubated with commensal bacteria (Bifidobacterium infantis or Lactobacillus salivarius), or with Salmonella typhimurium, its flagellin, Clostridium difficile, Mycobacterium paratuberculosis, or Mycobacterium smegmatis for varying times. In some studies, HT-29 cells were pre-treated with a commensal strain for 2 hr prior to infection or flagellin stimulation. CCL20 and interleukin (IL)-8 secretion and nuclear factor (NF)-kappaB activation were measured using enzyme-linked immunosorbent assays. RESULTS: Compared to untreated cells, S. typhimurium, C. difficile, M. paratuberculosis, and flagellin activated NF-kappaB and stimulated significant secretion of CCL20 and IL-8 by HT-29 cells. Conversely, B. infantis, L. salivarius or M. smegmatis did not activate NF-kappaB or augment CCL20 or IL-8 production. Treatment with B. infantis, but not L. salivarius, dose-dependently inhibited the baseline secretion of CCL20. In cells pre-treated with B. infantis, C. difficile-, S. typhimurium-, and flagellin-induced CCL20 were significantly attenuated. B. infantis did not limit M. Paratuberculosis-induced CCL20 secretion. CONCLUSION: This study is the first to demonstrate that a commensal strain can attenuate CCL20 secretion in HT-29 IECs. Collectively, the data indicate that M. paratuberculosis may mediate mucosal damage and that B. infantis can exert immunomodulatory effects on IECs that mediate host responses to flagellin and flagellated enteric pathogens.

  13. 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.

  14. Modelling antagonic effect of lactic acid eacteria supernatants on some pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Augustus Caeser Franke Portella

    2009-11-01

    Full Text Available This work presents a statistical model of survival analysis for three pathogenic bacterial strains (Escherichia coli, Listeria monocytogenes and Staphylococcus aureus, when treated with neutralized and non-neutralized filtered supernatants broth from cultures of Lactobacillus acidhophilus, Lactobacillus rhamnosus and Lactobacillus sake. Survival analysis is a method employed to determine the period of time from an initial stage up to the occurrence of a particular event of interest, as death or a particular culture growth failure. In order to evaluate the potential efficacy of the ahead mentioned lactic acid bacteria when used as bioprotective starters in foods, experimental data were statistically treated and expressed by simple representative curves. Following the methodology of Cox and Kaplan-Meier, it was possible to make the selection of the best bioprotective lactic starter, as a predictive tool for evaluation of shelf life and prevention of eventual risks in fresh sausages and other similar food products.Este trabalho apresenta um modelo estatístico de análise de sobrevivência para três bactérias patogénicas (Escherichia coli, Listeria monocytogenes e Staphylococcus aureus, quando tratados com sobrenadantes filtrados neutralizado e não neutralizado provenientes de culturas de Lactobacillus acidhophilus, Lactobacillus rhamnosus e Lactobacillus sake. A Análise de sobrevivência é um método utilizado para determinar o período de tempo a partir de uma fase inicial até a ocorrência de um determinado evento de interesse, como a morte ou a inibição de uma particular cultura, a fim de avaliar a eficácia potencial das referidas bactérias lácticas quando usadas como bioproteção em alimentos. Os dados experimentais foram tratados estatisticamente, seguindo a metodologia de Cox e Kaplan-Meier e foi possível fazer a seleção dos melhores fermentos láticos bioprotectivos, como uma ferramenta para avaliação preditiva, vida de

  15. Competition for attachment of aquaculture candidate probiotic and pathogenic bacteria on fish intestinal mucus.

    Science.gov (United States)

    Vine, N G; Leukes, W D; Kaiser, H; Daya, S; Baxter, J; Hecht, T

    2004-06-01

    Probiotics for aquaculture are generally only selected by their ability to produce antimicrobial metabolites; however, attachment to intestinal mucus is important in order to remain within the gut of its host. Five candidate probiotics (AP1-AP5), isolated from the clownfish, Amphiprion percula (Lacepéde), were examined for their ability to attach to fish intestinal mucus and compete with two pathogens, Aeromonas hydrophila and Vibrio alginolyticus. Two different radioactive isotopes were used to quantify competition between pathogens and probionts. Attachment of the pathogens was enhanced by the presence of the candidate probiotics. However, the addition of the candidate probiotics after the pathogens resulted in reduced pathogen attachment. Only AP5 caused lower attachment success of V. alginolyticus when added before the pathogen. When AP5 was added first, the average attachment change was 41% compared with 72% when added after V. alginolyticus, suggesting that the probiotic is displaced but that enhanced attachment of the pathogen does not occur. Conversely, when V. alginolyticus was added first, followed by AP5, attachment change was 37% while AP5 had 92% attachment change when added second. This implies that the pathogen was displaced by the candidate probiotic and therefore it appeared that, based on the ability of probiont AP5 to attach to mucus, the growth of the pathogen in the digestive tract might be suppressed by the candidate probiont's presence.

  16. Influence of Co-Doping of Ni (II on Photocatalytic Activity of TiO2 for Pathogenic Bacteria Inhibition

    Directory of Open Access Journals (Sweden)

    Baharuddin Shaleh

    2010-04-01

    Full Text Available Nanoparticle titanium dioxide (TiO2 has most attention in the past decade, since it can be applied as alternative material on sterilization photocatalyst process. This research focused on increasing performance of titania such as structure, particles size and surface area through Ni ion doped on TiO2 surface by sol-gel technique. Product were used to design of a photobioreactor for sterilization process from pathogenic bacteria such as Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Product were characterized using TG-DTA, XRD, TEM, SEM-EDS and BET. Titanium dioxide with anatase structure have 12.1 nm in particles size and surface area 49.6 m2/ g that have higher inhibition rate to bacteria cell. Photobiocatalytic reaction was carried out in various TiO2-Ni concentration and UV irradiation times. The anti bacteria from TiO2-Ni to all bacteria cell suspension after UV irradiated at λm : 365 nm has good synergistic effect. Effect of mechanical treatment by sonicator showed the increasing inhibition rate around 4% for 120 minute irradiation. Inhibition rate optimization for each bacteria gave different efficiency inhibition to TiO2-Ni concentration 1.5-2.0 g/L. TiO2-Ni inhibited growth of Escherichia coli, Staphylococcus aureus around ≥ 95% for 120 minute irradiation, while Bacillus subtilis resistance with inhibition percentage rate only 88.1%.

  17. Antimicrobial activities of commercial essential oils and their components against food-borne pathogens and food spoilage bacteria.

    Science.gov (United States)

    Mith, Hasika; Duré, Rémi; Delcenserie, Véronique; Zhiri, Abdesselam; Daube, Georges; Clinquart, Antoine

    2014-07-01

    This study was undertaken to determine the in vitro antimicrobial activities of 15 commercial essential oils and their main components in order to pre-select candidates for potential application in highly perishable food preservation. The antibacterial effects against food-borne pathogenic bacteria (Listeria monocytogenes, Salmonella Typhimurium, and enterohemorrhagic Escherichia coli O157:H7) and food spoilage bacteria (Brochothrix thermosphacta and Pseudomonas fluorescens) were tested using paper disk diffusion method, followed by determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Most of the tested essential oils exhibited antimicrobial activity against all tested bacteria, except galangal oil. The essential oils of cinnamon, oregano, and thyme showed strong antimicrobial activities with MIC ≥ 0.125 μL/mL and MBC ≥ 0.25 μL/mL. Among tested bacteria, P. fluorescens was the most resistant to selected essential oils with MICs and MBCs of 1 μL/mL. The results suggest that the activity of the essential oils of cinnamon, oregano, thyme, and clove can be attributed to the existence mostly of cinnamaldehyde, carvacrol, thymol, and eugenol, which appear to possess similar activities against all the tested bacteria. These materials could be served as an important natural alternative to prevent bacterial growth in food products.

  18. Commercial probiotic bacteria and prebiotic carbohydrates: a fundamental study on prebiotics uptake, antimicrobials production and inhibition of pathogens.

    Science.gov (United States)

    Cruz-Guerrero, Alma; Hernández-Sánchez, Humberto; Rodríguez-Serrano, Gabriela; Gómez-Ruiz, Lorena; García-Garibay, Mariano; Figueroa-González, Ivonne

    2014-08-01

    Probiotics and prebiotics are among the most important functional food ingredients worldwide. The proven benefits of such ingredients to human health have encouraged the development of functional foods containing both probiotics and prebiotics. In this work, the production of antimicrobial compounds coupled to the uptake of commercial prebiotics by probiotic bacteria was investigated. The probiotic bacteria studied were able to take up commercial prebiotic carbohydrates to the same or higher extent than that observed for lactose (control carbohydrate). The growth of probiotic bacteria was coupled to the production of antimicrobials such as short-chain fatty acids (SCFA), H2 O2 and bacteriocins. A higher production of antimicrobial compounds was recorded with Oligomate 55® compared with Regulact® and Frutafit® (3-5 and 10-115 times higher SCFA and H2 O2 production, respectively). The probiotic bacteria grown with Oligomate 55® also produced bacteriocins and other non-identified antimicrobial compounds. The antimicrobials produced by the probiotic bacteria inhibited up to 50% the growth of model pathogens such as Escherichia coli, Listeria innocua and Micrococcus luteus compared with control cultures. The results here obtained are useful for the adequate selection of probiotic/prebiotics pairs and therefore in the development of efficient functional foods. © 2013 Society of Chemical Industry.

  19. Antimicrobial activities of commercial essential oils and their components against food-borne pathogens and food spoilage bacteria

    Science.gov (United States)

    Mith, Hasika; Duré, Rémi; Delcenserie, Véronique; Zhiri, Abdesselam; Daube, Georges; Clinquart, Antoine

    2014-01-01

    This study was undertaken to determine the in vitro antimicrobial activities of 15 commercial essential oils and their main components in order to pre-select candidates for potential application in highly perishable food preservation. The antibacterial effects against food-borne pathogenic bacteria (Listeria monocytogenes, Salmonella Typhimurium, and enterohemorrhagic Escherichia coli O157:H7) and food spoilage bacteria (Brochothrix thermosphacta and Pseudomonas fluorescens) were tested using paper disk diffusion method, followed by determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Most of the tested essential oils exhibited antimicrobial activity against all tested bacteria, except galangal oil. The essential oils of cinnamon, oregano, and thyme showed strong antimicrobial activities with MIC ≥ 0.125 μL/mL and MBC ≥ 0.25 μL/mL. Among tested bacteria, P. fluorescens was the most resistant to selected essential oils with MICs and MBCs of 1 μL/mL. The results suggest that the activity of the essential oils of cinnamon, oregano, thyme, and clove can be attributed to the existence mostly of cinnamaldehyde, carvacrol, thymol, and eugenol, which appear to possess similar activities against all the tested bacteria. These materials could be served as an important natural alternative to prevent bacterial growth in food products. PMID:25473498

  20. A simplified experimental model for clearance of some pathogenic bacteria using common bacterivorous ciliated spp. in Tigris river

    Science.gov (United States)

    Ali, Talib Hassan; Saleh, Dhuha Saad

    2014-03-01

    Bacteria-specific uptake rates of three different protozoan taxa on a pure and mixed bacterial community was studied by means of a simplified and functionally reproducible experimental model. The bacterial species Shigella flexneri, Escherichia coli and Salmonella typhi were isolated and classified from stool samples of patients suffering from diarrhea. Paramecium caudatum, Tetrahymena pyriformis and Halteria grandinella, free living ciliate Protozoans, were isolated and identified from Tigris river water. Pure and mixed ( E. coli + S. typhi), ( E. coli + Sh. flexneri) bacterial cultures were used with each ciliate genera to evaluate the following: predator duplication rate, prey reduction rate, clearance rate and net grazing rate. We used selective lactose fermentation phenomena of enteric bacteria on MacConkey medium for the quantification of bacteria cultural characteristics. The final bacteria concentration was reduced by growing protozoa of 98-99.9 % compared to protozoa-free controls. It showed that Tetrahymena pyriformis had the highest duplication rate (4.13 time/day) in both types of cultures (pure and mixed), followed by Paramecium caudatum and Halteria grandinella, respectively. Paramecium caudatum had the highest rate of ingestion in both types of cultures (26 × 103 bacteria/organism/hr) and yielded the longest time required for 90 % bacterial reduction in a pure suspension of S. typhi (166 h). Clearance rates of pathogenic bacteria by ciliates ranged between 106 nanoliter/organism/h by P. caudatum to S. typhi and 1.92 nanoliter/organism/h seen in T. pyriformis in ( E. coli + S. typhi) mixed culture. We used aquatic experimental microcosms under controlled conditions to explore bacteria-dependent ciliate growth and examined whether these ciliates could discriminate between equally sized bacterial preys in a mixture.

  1. On the trail of EHEC/EAEC--unraveling the gene regulatory networks of human pathogenic Escherichia coli bacteria.

    Science.gov (United States)

    Pauling, Josch; Röttger, Richard; Neuner, Andreas; Salgado, Heladia; Collado-Vides, Julio; Kalaghatgi, Prabhav; Azevedo, Vasco; Tauch, Andreas; Pühler, Alfred; Baumbach, Jan

    2012-07-01

    Pathogenic Escherichia coli, such as Enterohemorrhagic E. coli (EHEC) and Enteroaggregative E. coli (EAEC), are globally widespread bacteria. Some may cause the hemolytic uremic syndrome (HUS). Varying strains cause epidemics all over the world. Recently, we observed an epidemic outbreak of a multi-resistant EHEC strain in Western Europe, mainly in Germany. The Robert Koch Institute reports >4300 infections and >50 deaths (July, 2011). Farmers lost several million EUR since the origin of infection was unclear. Here, we contribute to the currently ongoing research with a computer-aided study of EHEC transcriptional regulatory interactions, a network of genetic switches that control, for instance, pathogenicity, survival and reproduction of bacterial cells. Our strategy is to utilize knowledge of gene regulatory networks from the evolutionary relative E. coli K-12, a harmless strain mainly used for wet lab studies. In order to provide high-potential candidates for human pathogenic E. coli bacteria, such as EHEC, we developed the integrated online database and an analysis platform EhecRegNet. We utilize 3489 known regulations from E. coli K-12 for predictions of yet unknown gene regulatory interactions in 16 human pathogens. For these strains we predict 40,913 regulatory interactions. EhecRegNet is based on the identification of evolutionarily conserved regulatory sites within the DNA of the harmless E. coli K-12 and the pathogens. Identifying and characterizing EHEC's genetic control mechanism network on a large scale will allow for a better understanding of its survival and infection strategies. This will support the development of urgently needed new treatments. EhecRegNet is online via http://www.ehecregnet.de.

  2. [Pathogenic bacteria dissemination by ants (Hymenoptera: Formicidae) in two hospitals in northeast Brazil].

    Science.gov (United States)

    Fontana, Renato; Wetler, Rita M da C; Aquino, Renata S S; Andrioli, João L; Queiroz, Guilherme R G; Ferreira, Sônia L; Nascimento, Ivan C do; Delabie, Jacques H C

    2010-01-01

    Nosocomial infections bring a high risk to the health of hospital patients and employees. Ants are common organisms in Brazilian hospitals, where they can act as dispersers of opportunistic microorganisms in places they forage. The occurrence of multi-resistant bacteria carried by ants was analyzed in two public hospitals (HA and HB) in southeastern Bahia, Brazil. In these two hospitals 132 workers belonging to three ant species were collected. The bacteria associated to these ants were identified and their susceptibility to antibiotics was evaluated. More than half (57.3%) of ants collected in HA were associated with some kind of bacteria, with 26.7% of them being opportunist bacteria, while 84,2% of the ants from HB presented associated bacteria growth, with 61.4% of them being opportunist bacteria. Twenty four species of bacteria were isolated. The Gram-positive bacilli of the genus Bacillus were the most frequent, followed by the Gram-positive cocci, Gram-negative bacilli (family Enterobacteriaceae) and Gram-negative non-fermenters bacilli. The profile of sensitivity of the bacterial isolates to drugs pointed out the existence of multi-resistant isolates carried by ants. For the first time, are reported cases of the same bacterial resistant isolates taken form homospecific ant workers that point out the importance of ants to bacteria dissemination and proliferation in a hospital. Our results suggest that the risk of contamination presented by these ants is similar to the one of any other mechanical vector of bacterial dissemination.

  3. Microgravity as a biological tool to examine host-pathogen interactions and to guide development of therapeutics and preventatives that target pathogenic bacteria.

    Science.gov (United States)

    Higginson, Ellen E; Galen, James E; Levine, Myron M; Tennant, Sharon M

    2016-11-01

    Space exploration programs have long been interested in the effects of spaceflight on biology. This research is important not only in its relevance to future deep space exploration, but also because it has allowed investigators to ask questions about how gravity impacts cell behavior here on Earth. In the 1980s, scientists designed and built the first rotating wall vessel, capable of mimicking the low shear environment found in space. This vessel has since been used to investigate growth of both microorganisms and human tissue cells in low shear modeled microgravity conditions. Bacterial behavior has been shown to be altered both in space and under simulated microgravity conditions. In some cases, bacteria appear attenuated, whereas in others virulence is enhanced. This has consequences not only for manned spaceflight, but poses larger questions about the ability of bacteria to sense the world around them. By using the microgravity environment as a tool, we can exploit this phenomenon in the search for new therapeutics and preventatives against pathogenic bacteria for use both in space and on Earth.

  4. Selection of media for antimicrobial susceptibility testing of fish pathogenic bacteria

    DEFF Research Database (Denmark)

    Dalsgaard, Inger

    2001-01-01

    The available data concerning antimicrobial susceptibility testing of fish pathogens showed that there is no consensus to the basal medium currently being employed. Different media recommended for susceptibility testing of human pathogens (Mueller-Hinton Agar, Tryptone Soya Agar, Antibiotic Medium...

  5. Selection of media for antimicrobial susceptibility testing of fish pathogenic bacteria

    DEFF Research Database (Denmark)

    Dalsgaard, Inger

    2001-01-01

    The available data concerning antimicrobial susceptibility testing of fish pathogens showed that there is no consensus to the basal medium currently being employed. Different media recommended for susceptibility testing of human pathogens (Mueller-Hinton Agar, Tryptone Soya Agar, Antibiotic Medium...

  6. Occurrence of potentially pathogenic bacteria on the hands of hospital patients before and after the introduction of patient hand disinfection.

    Science.gov (United States)

    Hedin, Göran; Blomkvist, Annika; Janson, Marianne; Lindblom, Anders

    2012-10-01

    The leading cause of nosocomial infections and spread of multiresistant bacteria is considered to be the failure of healthcare workers to perform appropriate hand hygiene. The role of the hands of hospital patients in the spread of infection has received little attention. The aim of the present study was to investigate the occurrence of potentially pathogenic bacteria on the patients' hands. Quantitative cultures were repeatedly taken from the fingertips of patients at a rehabilitation clinic before and after an intervention in which patient hand disinfection was introduced and promoted. Before the intervention, the occurrence on the hands of Escherichia coli, Klebsiella spp., enterococci, Staphylococcus aureus and yeast was a common finding. The colony counts of S. aureus were often higher than the counts of other organisms. After the intervention, the level of hand contamination was lower. The difference was statistically significant (p < 0.05) concerning Enterobacteriaceae, both when the patients were resting and at lunch time, for enterococci and total bacterial counts at lunch time, and for yeast when they were resting. Concerning S. aureus, the difference was not statistically significant, neither while resting nor at lunch time. The role of the patients in the spread of pathogenic bacteria merits more discussion.

  7. Glycosaminoglycans are involved in pathogen adherence to corneal epithelial cells differently for Gram-positive and Gram-negative bacteria

    Directory of Open Access Journals (Sweden)

    Beatriz García

    2016-11-01

    Full Text Available The epithelium of the cornea is continuously exposed to pathogens, and adhesion to epithelial cells is regarded as an essential first step in bacterial pathogenesis. In this article, the involvement of glycosaminoglycans in the adhesion of various pathogenic bacteria to corneal epithelial cells is analyzed. All microorganisms use glycosaminoglycans as receptors, but arranged in different patterns depending on the Gram-type of the bacterium. The heparan sulfate chains of syndecans are the main receptors, though other molecular species also seem to be involved, particularly in Gram-negative bacteria. Adherence is inhibited differentially by peptides, including heparin binding sequences, indicating the participation of various groups of Gram-positive and -negative adhesins. The length of the saccharides produces a major effect, and low molecular weight chains inhibit the binding of Gram-negative microorganisms but increase the adherence of Gram-positives. Pathogen adhesion appears to occur preferentially through sulfated domains, and is very dependent on N- and 6-O-sulfation of the glucosamine residue and, to a lesser extent, 2-O sulfation of uronic acid. These data show the differential use of corneal receptors, which could facilitate the development of new anti-infective strategies.

  8. Food-borne zoonotic pathogens and antimicrobial resistance of indicator bacteria in urban wild boars in Barcelona, Spain.

    Science.gov (United States)

    Navarro-Gonzalez, Nora; Casas-Díaz, Encarna; Porrero, Concepción M; Mateos, Ana; Domínguez, Lucas; Lavín, Santiago; Serrano, Emmanuel

    2013-12-27

    Wildlife is increasingly abundant in urban environments, but little is known about the zoonotic pathogens carried by these populations. Urban wild boars are of particular concern because this species is well-known as a pathogen reservoir, and thus, we studied selected zoonotic pathogens in urban wild boars in Barcelona, Spain (n=41). Salmonella enterica was found in 5.00% (95% CI 0.61-16.91) and Campylobacter coli in 4.88% (95% CI 0.6-16.53) of the animals. E. coli O157:H7 and C. jejuni were not found. Other thermophilic Campylobacter were moderately prevalent (19.51%, 95% CI 8.82-34.87). Additionally, we screened for antimicrobial resistance in indicator bacteria: resistance was most frequent in Enterococcus faecium (95% of the isolates were resistant to at least one antimicrobial agent), followed by Enterococcus faecalis (50%) and Escherichia coli (10%). For the first time resistance to linezolid in bacteria carried by wildlife is reported. These findings pose a concern for public health, and thus, further research is needed on wildlife in urban environments.

  9. A recombinant horseshoe crab plasma lectin recognizes specific pathogen-associated molecular patterns of bacteria through rhamnose.

    Directory of Open Access Journals (Sweden)

    Sim-Kun Ng

    Full Text Available Horseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs, yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL in an Escherichia coli system. Interestingly, rHPL bound not only to bacteria and LPSs like the native HPL but also to selective medically important pathogens isolated from clinical specimens, such as Gram-negative Pseudomonas aeruginosa and Klebsiella pneumoniae and Gram-positive Streptococcus pneumoniae serotypes. The binding was demonstrated to occur through a specific molecular interaction with rhamnose in pathogen-associated molecular patterns (PAMPs on the bacterial surface. Additionally, rHPL inhibited the growth of P. aeruginosa PAO1 in a concentration-dependent manner. The results suggest that a specific protein-glycan interaction between rHPL and rhamnosyl residue may further facilitate development of novel diagnostic and therapeutic strategies for microbial pathogens.

  10. A recombinant horseshoe crab plasma lectin recognizes specific pathogen-associated molecular patterns of bacteria through rhamnose.

    Science.gov (United States)

    Ng, Sim-Kun; Huang, Yu-Tsyr; Lee, Yuan-Chuan; Low, Ee-Ling; Chiu, Cheng-Hsun; Chen, Shiu-Ling; Mao, Liang-Chi; Chang, Margaret Dah-Tsyr

    2014-01-01

    Horseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs), yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL) in an Escherichia coli system. Interestingly, rHPL bound not only to bacteria and LPSs like the native HPL but also to selective medically important pathogens isolated from clinical specimens, such as Gram-negative Pseudomonas aeruginosa and Klebsiella pneumoniae and Gram-positive Streptococcus pneumoniae serotypes. The binding was demonstrated to occur through a specific molecular interaction with rhamnose in pathogen-associated molecular patterns (PAMPs) on the bacterial surface. Additionally, rHPL inhibited the growth of P. aeruginosa PAO1 in a concentration-dependent manner. The results suggest that a specific protein-glycan interaction between rHPL and rhamnosyl residue may further facilitate development of novel diagnostic and therapeutic strategies for microbial pathogens.

  11. Detection of pathogenic bacteria in skin lesions of patients with chiclero's ulcer: reluctant response to antimonial treatment

    Directory of Open Access Journals (Sweden)

    Isaac-Márquez Angélica Patricia

    2003-01-01

    Full Text Available We investigated the bacterial flora present in skin lesions of patients with chiclero's ulcer from the Yucatan peninsula of Mexico using conventional culture methods (11 patients, and an immunocolorimetric detection of pathogenic Streptococcus pyogenes (15 patients. Prevalence of bacteria isolated by culture methods was 90.9% (10/11. We cultured, from chiclero's ulcers (60%, pathogenic bacterial such as Staphylococcus aureus (20%, S. pyogenes (1.6%, Pseudomonas aeruginosa (1.6%, Morganella morganii (1.6%, and opportunist pathogenic bacteria such as Klebsiella spp. (20.0%, Enterobacter spp. (20%, and Enterococcus spp. (20%. We also cultured coagulase-negative staphylococci in 40% (4/10 of the remaining patients. Micrococcus spp. and coagulase-negative staphylococci constituted the bacterial genuses more frequently isolated in the normal skin of patients with chiclero's ulcer and healthy individuals used as controls. We also undertook another study to find out the presence of S. pyogenes by an immunocolorimetric assay. This study indicated that 60% (9/15 of the ulcerated lesions, but not normal controls, were contaminated with S. pyogenes. Importantly, individuals with purulent secretion and holding concomitant infections with S. pyogenes, S. aureus, P. aeruginosa, M. morganii, and E. durans took longer to heal Leishmania (L. mexicana infections treated with antimonial drugs. Our results suggest the need to eliminate bacterial purulent infections, by antibiotic treatment, before starting antimonial administration to patients with chiclero's ulcer.

  12. Antibacterial Effects of (Mentha X Piperita L. Hydroalcoholic Extract on the Six Food-Borne Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    H Zandi

    2016-11-01

    Full Text Available Abstract Introduction: Iran is the richest country in terms of distribution of medicinal plants. The antimicrobial effect of plant extracts and essential oils is well known and they are used as a good substitute in food industry to control food-borne pathogens. Due to the antibacterial activity of plant extracts and their efficacy against microorganisms, the aim of this study was to investigate the antibacterial activity of peppermint extract in order to control pathogenic bacteria. Methods: Piperita L., which is one of the species of mint; was used in this invitro-experimental study. The extraction was performed by percolation method. Well - agar method was used for antibacterial effects of extracts. The minimum inhibitory concentration (MIC and minimal bactericidal concentration (MBC were done for six standard bacteria using microdilution method. The test was performed 3 times for each bacterium. Data were analyzed by using SPSS version 16 and t-test. Results: The lowest MIC of peppermint extract on examined microorganisms were observed for Staphylococcus aureus and Enterococcus faecalis (3.25 mg/ ml. Also the maximum diameter of inhibition zone, was related to Staphylococcus aureus (32 mm. Conclusion: Results of this study indicated that peppermint extract has a favorable control effect on the growth of food borne pathogens, which can be used as a perfect preservative for keeping food.

  13. Recyclable Photo-Thermal Nano-Aggregates of Magnetic Nanoparticle Conjugated Gold Nanorods for Effective Pathogenic Bacteria Lysis.

    Science.gov (United States)

    Ramasamy, Mohankandhasamy; Kim, Sanghyo; Lee, Su Seong; Yi, Dong Kee

    2016-01-01

    We describe the nucleophilic hybridization technique for fabricating magnetic nanoparticle (MNP) around gold nanorod (AuNR) for desired photo-thermal lysis on pathogenic bacteria. From the electromagnetic energy conversion into heat to the surrounding medium, a significant and quicker temperature rise was noted after light absorption on nanohybrids, at a controlled laser light output and optimum nanoparticle concentration. We observed a similar photo-thermal pattern for more than three times for the same material up on repeated magnetic separation. Regardless of the cell wall nature, superior pathogenic cell lysis has been observed for the bacteria suspensions of individual and mixed samples of Salmonella typhi (S.typhi) and Bacillus subtilis (B.subtilis) by the photo-heated nanoparticles. The synthesis of short gold nanorod, conjugation with magnetic nanoparticle and its subsequent laser exposure provides a rapid and reiterated photo-thermal effect with enhanced magnetic separation for efficient bactericidal application in water samples. Resultant novel properties of the nano-aggregates makes them a candidate to be used for a rapid, effective, and re-iterated photo-thermal agent against a wide variety of pathogens to attain microbe free water.

  14. Size-dependent toxicity of silver nanoparticles to bacteria, yeast, algae, crustaceans and mammalian cells in vitro.

    Directory of Open Access Journals (Sweden)

    Angela Ivask

    Full Text Available The concept of nanotechnologies is based on size-dependent properties of particles in the 1-100 nm range. However, the relation between the particle size and biological effects is still unclear. The aim of the current paper was to generate and analyse a homogenous set of experimental toxicity data on Ag nanoparticles (Ag NPs of similar coating (citrate but of 5 different primary sizes (10, 20, 40, 60 and 80 nm to different types of organisms/cells commonly used in toxicity assays: bacterial, yeast and algal cells, crustaceans and mammalian cells in vitro. When possible, the assays were conducted in ultrapure water to minimise the effect of medium components on silver speciation. The toxic effects of NPs to different organisms varied about two orders of magnitude, being the lowest (∼0.1 mg Ag/L for crustaceans and algae and the highest (∼26 mg Ag/L for mammalian cells. To quantify the role of Ag ions in the toxicity of Ag NPs, we normalized the EC50 values to Ag ions that dissolved from the NPs. The analysis showed that the toxicity of 20-80 nm Ag NPs could fully be explained by released Ag ions whereas 10 nm Ag NPs proved more toxic than predicted. Using E. coli Ag-biosensor, we demonstrated that 10 nm Ag NPs were more bioavailable to E. coli than silver salt (AgNO3. Thus, one may infer that 10 nm Ag NPs had more efficient cell-particle contact resulting in higher intracellular bioavailability of silver than in case of bigger NPs. Although the latter conclusion is initially based on one test organism, it may lead to an explanation for "size-dependent" biological effects of silver NPs. This study, for the first time, investigated the size-dependent toxic effects of a well-characterized library of Ag NPs to several microbial species, protozoans, algae, crustaceans and mammalian cells in vitro.

  15. Computational analyses of an evolutionary arms race between mammalian immunity mediated by immunoglobulin A and its subversion by bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Ana Pinheiro

    Full Text Available IgA is the predominant immunoglobulin isotype in mucosal tissues and external secretions, playing important roles both in defense against pathogens and in maintenance of commensal microbiota. Considering the complexity of its interactions with the surrounding environment, IgA is a likely target for diversifying or positive selection. To investigate this possibility, the action of natural selection on IgA was examined in depth with six different methods: CODEML from the PAML package and the SLAC, FEL, REL, MEME and FUBAR methods implemented in the Datamonkey webserver. In considering just primate IgA, these analyses show that diversifying selection targeted five positions of the Cα1 and Cα2 domains of IgA. Extending the analysis to include other mammals identified 18 positively selected sites: ten in Cα1, five in Cα2 and three in Cα3. All but one of these positions display variation in polarity and charge. Their structural locations suggest they indirectly influence the conformation of sites on IgA that are critical for interaction with host IgA receptors and also with proteins produced by mucosal pathogens that prevent their elimination by IgA-mediated effector mechanisms. Demonstrating the plasticity of IgA in the evolution of different groups of mammals, only two of the eighteen selected positions in all mammals are included in the five selected positions in primates. That IgA residues subject to positive selection impact sites targeted both by host receptors and subversive pathogen ligands highlights the evolutionary arms race playing out between mammals and pathogens, and further emphasizes the importance of IgA in protection against mucosal pathogens.

  16. Computational Analyses of an Evolutionary Arms Race between Mammalian Immunity Mediated by Immunoglobulin A and Its Subversion by Bacterial Pathogens

    Science.gov (United States)

    Pinheiro, Ana; Woof, Jenny M.; Abi-Rached, Laurent; Parham, Peter; Esteves, Pedro J.

    2013-01-01

    IgA is the predominant immunoglobulin isotype in mucosal tissues and external secretions, playing important roles both in defense against pathogens and in maintenance of commensal microbiota. Considering the complexity of its interactions with the surrounding environment, IgA is a likely target for diversifying or positive selection. To investigate this possibility, the action of natural selection on IgA was examined in depth with six different methods: CODEML from the PAML package and the SLAC, FEL, REL, MEME and FUBAR methods implemented in the Datamonkey webserver. In considering just primate IgA, these analyses show that diversifying selection targeted five positions of the Cα1 and Cα2 domains of IgA. Extending the analysis to include other mammals identified 18 positively selected sites: ten in Cα1, five in Cα2 and three in Cα3. All but one of these positions display variation in polarity and charge. Their structural locations suggest they indirectly influence the conformation of sites on IgA that are critical for interaction with host IgA receptors and also with proteins produced by mucosal pathogens that prevent their elimination by IgA-mediated effector mechanisms. Demonstrating the plasticity of IgA in the evolution of different groups of mammals, only two of the eighteen selected positions in all mammals are included in the five selected positions in primates. That IgA residues subject to positive selection impact sites targeted both by host receptors and subversive pathogen ligands highlights the evolutionary arms race playing out between mammals and pathogens, and further emphasizes the importance of IgA in protection against mucosal pathogens. PMID:24019941

  17. Pathogenic bacteria and microbial-source tracking markers in Brandywine Creek Basin, Pennsylvania and Delaware, 2009-10

    Science.gov (United States)

    Duris, Joseph W.; Reif, Andrew G.; Olson, Leif E.; Johnson, Heather E.

    2011-01-01

    The City of Wilmington, Delaware, is in the downstream part of the Brandywine Creek Basin, on the main stem of Brandywine Creek. Wilmington uses this stream, which drains a mixed-land-use area upstream, for its main drinking-water supply. Because the stream is used for drinking water, Wilmington is in need of information about the occurrence and distribution of specific fecally derived pathogenic bacteria (disease-causing bacteria) and their relations to commonly measured fecal-indicator bacteria (FIB), as well as information regarding the potential sources of the fecal pollution and pathogens in the basin. This study focused on five routinely sampled sites within the basin, one each on the West Branch and the East Branch of Brandywine Creek and at three on the main stem below the confluence of the West and East Branches. These sites were sampled monthly for 1 year. Targeted event samples were collected on two occasions during high flow and two occasions during normal flow. On the basis of this study, high flows in the Brandywine Creek Basin were related to increases in FIB densities, and in the frequency of selected pathogen and source markers, in the West Branch and main stem of Brandywine Creek, but not in the East Branch. Water exceeding the moderate fullbody-contact single-sample recreational water-quality criteria (RWQC) for Escherichia coli (E. coli) was more likely to contain selected markers for pathogenic E. coli (eaeA,stx1, and rfbO157 gene markers) and bovine fecal sources (E. hirae and LTIIa gene markers), whereas samples exceeding the enterococci RWQC were more likely to contain the same pathogenic markers but also were more likely to carry a marker indicative of human source (esp gene marker). On four sample dates, during high flow between October and March, the West Branch was the only observed potential contributor of selected pathogen and bovine source markers to the main stem of Brandywine Creek. Indeed, the stx2 marker, which indicates a highly

  18. Determination of common pathogenic bacteria of blast injury to the limbs in plateau area and related research

    Directory of Open Access Journals (Sweden)

    Zheng-lei WANG

    2015-11-01

    Full Text Available Objective To investigate the common pathogenic bacteria and their drug susceptibility in the wounds in the limbs as a result of blast injury in plateau with a low temperature so as to provide a basis for prevention and treatment of war wound infection in such area. Methods The model of blast injury was reproduced to the hind legs of 800 rabbits in cold and dry plateau. 1, 3, 6, 12, 24, 48, 72 and 96h after injury, the general condition and vital signs of the wounded were observed, and bacterial culture, flora analysis and drug susceptibility test of excretion from wound tract, air, surface of snow, soil and animal fur were performed. Results Micrococciand Bacilliwere found in air and snow. Bacillus subtilis, Escherichia coliand Pseudomonas aeruginosawere found in soil, and Staphylococcus aureus, Acinetobacters, Pseudomonas aeruginosaand Escherichia coliin rabbit fur. The respiration and pulse became faster, and body temperature lowered after injury compared with that before injury. G+ bacteria were found in most wound tract secretions, and the frequency of the bacterial strains in descending order were Bacillus subtilis, coagulase-negative Staphylococci, E. coli, Pseudomonas aeruginosa, Stenotrophomonas maltophiliastrains. The sensitive antibiotics for these G+ bacteria were ofloxacin, ciprofloxacin, erythromycin. Susceptible G– bacteria were susceptible to ceftazidime, minocycline, sulfamethoxazole etc. Conclusions The growth of bacteria in the wounds as a result of blast injury grow slower in cold and dry alpine area. The time of debridement may be delayed for 2-3h. G+ bacteria were main susceptible flora to antibiotics, and it is related to the bacterial flora of the surrounding environment, thus it is suggested that a combination of different antibiotics (ofloxacin, ciprofloxacin or erythromycin alone combined with ceftazidime, minocycline or cotrimoxazole alone are needed to prevent infection after blast injury. DOI: 10.11855/j

  19. THE EXISTENCE OF PATHOGENIC BACTERIA Vibrio cholerae IN SOME FISHERY PRODUCTS SOLD IN DENPASAR CITY TRADITIONAL MARKET

    Directory of Open Access Journals (Sweden)

    I Wayan Yogi Widyastana

    2015-03-01

    Full Text Available The purpose of this research was to find out the existence of Vibrio cholerae, bacteria that may cause cholera disease, in some fishery products in Denpasar traditional market, Bali. This research used samples taken from three different fisheries products: tuna fishes (Euthynnus affinis, shrimps (Penaeus indicus, and shellfish (Anodonta sp.. They were taken from three traditional markets in Denpasar City: Ketapian, Kumbasari, and Pidada Markets. All samples were cultured on Alkaline Peptone Water (APW media, continued by Thiosulfate Citrate Bile Salt Sucrose (TCBS, and then Biochemical Test and Serology Test undertaken. The results of this study showed that two (7.4% samples taken from Ketapian Market were proved to be positive containing pathogenic bacteria of V. cholerae; they were the shrimps with UA2 code and the shellfish with KA2 code. Meanwhile, there were no V. cholerae contaminations proven to exist in two other kind of products in other two traditional markets.

  20. Prevalence and persistence of potentially pathogenic and antibiotic resistant bacteria during anaerobic digestion treatment of cattle manure.

    Science.gov (United States)

    Resende, Juliana Alves; Silva, Vânia Lúcia; de Oliveira, Tamara Lopes Rocha; de Oliveira Fortunato, Samuel; da Costa Carneiro, Jailton; Otenio, Marcelo Henrique; Diniz, Cláudio Galuppo

    2014-02-01

    Anaerobic digestion figures as a sustainable alternative to avoid discharge of cattle manure in the environment, which results in biogas and biofertilizer. Persistence of potentially pathogenic and drug-resistant bacteria during anaerobic digestion of cattle manure was evaluated. Selective cultures were performed for enterobacteria (ENT), non-fermenting Gram-negative rods (NFR) and Gram-positive cocci (GPC). Antimicrobial susceptibility patterns were determined and a decay of all bacterial groups was observed after 60days. Multidrug-resistant bacteria were detected both the influent and effluent. GPC, the most prevalent group was highly resistant against penicillin and levofloxacin, whereas resistance to ampicillin, ampicillin-sulbactam and chloramphenicol was frequently observed in the ENT and NFR groups. The data point out the need of discussions to better address management of biodigesters and the implementation of sanitary and microbiological safe treatments of animal manures to avoid consequences to human, animal and environmental health. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Coliform and human pathogenic bacteria in tourism affected water bodies in North Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.

    forms of biota. Thus, bacteria as a community are useful and reliable indicators of ecosystem alterations. Through careful planning, choice, and analysis of relevant bacteriological parameters, deeper insights on quality, health, and stability of natural...

  2. Mechanisms of infection by pathogens transmitted by ticks on the example of bacteria: Anaplasma phagocytophilum and Borrelia burgdorferi

    Directory of Open Access Journals (Sweden)

    Paula Wróblewska

    2016-06-01

    Full Text Available Tick-borne diseases are transmission diseases belonging to the group of zoonoses but carried by ticks. These diseases are a major public health problem but also a problem for groups occupationally exposed to tick bites. Ixodes ricinus is a species of ticks which is the most common reservoir and the vector of a large number of microorganisms pathogenic to humans. It transfers, among others, bacteria of the species: Anaplasma phagocytophilum and Borrelia burgdorferi. The article discusses the mechanisms of infection with Borrelia burgdorferi and Anaplasma phagocytophilum for both ticks as well as for animals and humans. The two microorganisms discussed have developed many characteristics and mechanisms of adaptation to the environment, as well as defense mechanisms against the body's immune response. Understanding the biology of ticks and the function of proteins produced by ticks and pathogenic microorganisms is the key in the development of effective treatments and prevention of Lyme disease and anaplasmosis.

  3. Highly active modulators of indole signaling alter pathogenic behaviors in Gram-negative and Gram-positive bacteria.

    Science.gov (United States)

    Minvielle, Marine J; Eguren, Kristen; Melander, Christian

    2013-12-16

    Indole is a universal signal that regulates various bacterial behaviors, such as biofilm formation and antibiotic resistance. To generate mechanistic probes of indole signaling and control indole-mediated pathogenic phenotypes in both Gram-positive and Gram-negative bacteria, we have investigated the use of desformylflustrabromine (dFBr) derivatives to generate highly active indole mimetics. We have developed non-microbicidal dFBr derivatives that are 27-2000 times more active than indole in modulating biofilm formation, motility, acid resistance, and antibiotic resistance. The activity of these analogues parallels indole, because they are dependent on temperature, the enzyme tryptophanase TnaA, and the transcriptional regulator SdiA. This investigation demonstrates that molecules based on the dFBr scaffold can alter pathogenic behaviors by mimicking indole-signaling pathways.

  4. OEM--a new medium for rapid isolation of onion-pathogenic and onion-associated bacteria.

    Science.gov (United States)

    Zaid, Ali M; Bonasera, Jean M; Beer, Steven V

    2012-12-01

    Onions (Allium cepa L.) are plagued by a number of bacterial pathogens including Pantoea ananatis, P. agglomerans, Burkholderia cepacia, Enterobacter cloacae, Pectobacterium carotovorum subsp. carotovorum, Xanthomonas axonopodis pv. axonopodis and several Pseudomonas spp. We developed a semi-selective medium, termed onion extract medium (OEM), to selectively and rapidly isolate bacteria pathogenic to and associated with onions and onion-related samples including bulbs, seeds, sets, transplant seedlings, soil and water. Most strains of interest grow sufficiently on OEM in 24h at 28°C for tentative identification based on colony morphology, facilitating further characterization by microbiological and/or molecular means. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Diversity of Gram negative bacteria antagonistic against major pathogens of rice from rice seed in the tropic environment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty-two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference!strains. Sixteen species or types of Pseudomonas and 17 genera of non-pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed were P. putida and P. fulva. About 17% of the strains of Pseudomonas and 2% of the non-pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents.

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

    DEFF Research Database (Denmark)

    Jonach, Beata Renata; Boye, Mette; Stockmarr, Anders

    2014-01-01

    pathogens. The microorganisms that for decades have been associated with enteritis and diarrhea in suckling piglets are: rotavirus A, coronavirus, enterotoxigenic Escherichia coli (ETEC), Clostridium perfringens type C, Cryptosporidium spp., Giardia spp., Cystoisospora suis and Strongyloides ransomi...

  7. Deep-sea hydrothermal vent bacteria related to human pathogenic Vibrio species

    National Research Council Canada - National Science Library

    Nur A. Hasan; Christopher J. Grim; Erin K. Lipp; Irma N. G. Rivera; Jongsik Chun; Bradd J. Haley; Elisa Taviani; Seon Young Choi; Mozammel Hoq; A. Christine Munk; Thomas S. Brettin; David Bruce; Jean F. Challacombe; J. Chris Detter; Cliff S. Han; Jonathan A. Eisen; Anwar Huq; Rita R. Colwell

    2015-01-01

    .... antiquarius is closely related to pathogenic Vibrio species, namely Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, and Vibrio vulnificus, but sufficiently divergent to warrant a separate species status. The V...

  8. Phylogenetic distribution of symbiotic bacteria from Panamanian amphibians that inhibit growth of the lethal fungal pathogen Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Becker, Matthew H; Walke, Jenifer B; Murrill, Lindsey; Woodhams, Douglas C; Reinert, Laura K; Rollins-Smith, Louise A; Burzynski, Elizabeth A; Umile, Thomas P; Minbiole, Kevin P C; Belden, Lisa K

    2015-04-01

    The introduction of next-generation sequencing has allowed for greater understanding of community composition of symbiotic microbial communities. However, determining the function of individual members of these microbial communities still largely relies on culture-based methods. Here, we present results on the phylogenetic distribution of a defensive functional trait of cultured symbiotic bacteria associated with amphibians. Amphibians are host to a diverse community of cutaneous bacteria and some of these bacteria protect their host from the lethal fungal pathogen Batrachochytrium dendrobatidis (Bd) by secreting antifungal metabolites. We cultured over 450 bacterial isolates from the skins of Panamanian amphibian species and tested their interactions with Bd using an in vitro challenge assay. For a subset of isolates, we also completed coculture experiments and found that culturing isolates with Bd had no effect on inhibitory properties of the bacteria, but it significantly decreased metabolite secretion. In challenge assays, approximately 75% of the bacterial isolates inhibited Bd to some extent and these inhibitory isolates were widely distributed among all bacterial phyla. Although there was no clear phylogenetic signal of inhibition, three genera, Stenotrophomonas, Aeromonas and Pseudomonas, had a high proportion of inhibitory isolates (100%, 77% and 73%, respectively). Overall, our results demonstrate that antifungal properties are phylogenetically widespread in symbiotic microbial communities of Panamanian amphibians and that some functional redundancy for fungal inhibition occurs in these communities. We hope that these findings contribute to the discovery and development of probiotics for amphibians that can mitigate the threat of chytridiomycosis. © 2015 John Wiley & Sons Ltd.

  9. Limits to compensatory adaptation and the persistence of antibiotic resistance in pathogenic bacteria

    OpenAIRE

    MacLean, R. Craig; Vogwill, Tom

    2014-01-01

    Antibiotic resistance carries a fitness cost that could potentially limit the spread of resistance in bacterial pathogens. In spite of this cost, a large number of experimental evolution studies have found that resistance is stably maintained in the absence of antibiotics as a result of compensatory evolution. Clinical studies, on the other hand, have found that resistance in pathogen populations usually declines after antibiotic use is stopped, suggesting that compensatory adaptation is not ...

  10. Point of care nucleic acid detection of viable pathogenic bacteria with isothermal RNA amplification based paper biosensor

    Science.gov (United States)

    Liu, Hongxing; Xing, Da; Zhou, Xiaoming

    2014-09-01

    Food-borne pathogens such as Listeria monocytogenes have been recognized as a major cause of human infections worldwide, leading to substantial health problems. Food-borne pathogen identification needs to be simpler, cheaper and more reliable than the current traditional methods. Here, we have constructed a low-cost paper biosensor for the detection of viable pathogenic bacteria with the naked eye. In this study, an effective isothermal amplification method was used to amplify the hlyA mRNA gene, a specific RNA marker in Listeria monocytogenes. The amplification products were applied to the paper biosensor to perform a visual test, in which endpoint detection was performed using sandwich hybridization assays. When the RNA products migrated along the paper biosensor by capillary action, the gold nanoparticles accumulated at the designated Test line and Control line. Under optimized experimental conditions, as little as 0.5 pg/μL genomic RNA from Listeria monocytogenes could be detected. The whole assay process, including RNA extraction, amplification, and visualization, can be completed within several hours. The developed method is suitable for point-of-care applications to detect food-borne pathogens, as it can effectively overcome the false-positive results caused by amplifying nonviable Listeria monocytogenes.

  11. Antimicrobial and efflux pump inhibitory activity of caffeoylquinic acids from Artemisia absinthium against gram-positive pathogenic bacteria.

    Directory of Open Access Journals (Sweden)

    Yiannis C Fiamegos

    Full Text Available BACKGROUND: Traditional antibiotics are increasingly suffering from the emergence of multidrug resistance amongst pathogenic bacteria leading to a range of novel approaches to control microbial infections being investigated as potential alternative treatments. One plausible antimicrobial alternative could be the combination of conventional antimicrobial agents/antibiotics with small molecules which block multidrug efflux systems known as efflux pump inhibitors. Bioassay-driven purification and structural determination of compounds from plant sources have yielded a number of pump inhibitors which acted against gram positive bacteria. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report the identification and characterization of 4',5'-O-dicaffeoylquinic acid (4',5'-ODCQA from Artemisia absinthium as a pump inhibitor with a potential of targeting efflux systems in a wide panel of gram-positive human pathogenic bacteria. Separation and identification of phenolic compounds (chlorogenic acid, 3',5'-ODCQA, 4',5'-ODCQA was based on hyphenated chromatographic techniques such as liquid chromatography with post column solid-phase extraction coupled with nuclear magnetic resonance spectroscopy and mass spectroscopy. Microbial susceptibility testing and potentiation of well know pump substrates revealed at least two active compounds; chlorogenic acid with weak antimicrobial activity and 4',5'-ODCQA with pump inhibitory activity whereas 3',5'-ODCQA was ineffective. These initial findings were further validated with checkerboard, berberine accumulation efflux assays using efflux-related phenotypes and clinical isolates as well as molecular modeling methodology. CONCLUSIONS/SIGNIFICANCE: These techniques facilitated the direct analysis of the active components from plant extracts, as well as dramatically reduced the time needed to analyze the compounds, without the need for prior isolation. The calculated energetics of the docking poses supported the

  12. Frost-related dieback of Swedish and Estonian Salix plantations due to pathogenic and ice nucleation-active bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cambours, M.A.

    2004-07-01

    During the past decade, important dieback has been observed in short-rotation forestry plantations of Salix viminalis and S. dasyclados in Sweden and Estonia, plantations from which the isolation of ice nucleation-active (INA) and pathogenic bacteria has also been reported. This thesis investigates the connection between bacterial infection and frost as a possible cause for such damage, and the role played by internal and external factors (e.g. plant frost sensitivity, fertilisation) in the dieback observed. Bacterial floras isolated from ten Salix clones growing on fertilised/unfertilised mineral soil or nitrogen-rich organic soil, were studied. Culturable bacterial communities present both in internal necrotic tissues and on the plant surface (i.e. epiphytes) were isolated on two occasions (spring and autumn). The strains were biochemically characterised (with gram, oxidase and fluorescence tests), and tested for ice nucleation-activity. Their pathogenic properties were studied with and without association to a freezing stress. Certain strains were eventually identified with BIOLOG plates and 16S rRNA analysis. A high number of culturable bacterial strains was found in the plant samplings, belonging mainly to Erwinia and Sphingomonas spp.; pathogenic and INA communities being mostly Erwinia-, Sphingomonas- and Xanthomonas-like. The generally higher plant dieback noted in the field on nutrient-rich soils and for frost sensitive clones was found connected to higher numbers of pathogenic and INA bacteria in the plants. We thus confirm Salix dieback to be related to a synergistic effect of frost and bacterial infection, possibly aggravated by fertilisation.

  13. Analysis of Pathogenic Bacteria in Reclaimed Water and Impact of UV Disinfection on the Removal of Pathogenic Bacteria%污水回用中主要病原菌解析及其紫外消毒效应

    Institute of Scientific and Technical Information of China (English)

    景明; 王磊

    2016-01-01

    本研究以污水处理厂二级出水中的微生物为研究对象,通过454焦磷酸测序技术分析其群落结构组成,揭示了主要病源菌的种类和比例;通过培养法、 qPCR、 Q-RT-PCR 这3种方法分析紫外剂量为60 mJ•cm -2时对指示菌大肠杆菌和典型病原菌沙门氏菌及分枝杆菌的去除特性.结果表明,二级出水中共有11种病原菌,主要为梭菌属(2.96%)、弓形杆菌属(0.82%)和分枝杆菌(0.36%).60 mJ•cm -2剂量的紫外消毒可以有效去除99.9%可培养的大肠杆菌和沙门氏菌,对可培养分枝杆菌的去除率不足90%.但是,该剂量紫外消毒对活性大肠杆菌、沙门氏菌和分枝杆菌的去除率较低,Q-RT-PCR 检测方法可以较准确评价微生物的存活状态.60 mJ•cm -2紫外剂量会导致大量病原菌进入具有活性但不可培养(VBNC)状态,需结合其他深度处理工艺进一步去除活性病原菌以保障污水回用的安全利用.%In the study, 454-pyrosequencing technology was employed to investigate the species of pathogenic bacteria and the proportion of each pathogen in secondary effluent. Culture-based, qPCR and Q-RT-PCR methods were employed to analyze the removal of indicator (E. coli) and pathogen (Salmonella and Mycobacterium) by ultraviolet (UV) disinfection at a dose of 60 mJ•cm - 2 . The results showed that 11 kinds of pathogenic bacteria were found and the most abundant potentially pathogenic bacteria in the secondary effluent were affiliated with the genera of Clostridium (2. 96% ), Arcobacter (0. 82% ) and Mycobacterium (0. 36% ). 99. 9% of culturable E. coli and Salmonella were removed by UV disinfection ( 60 mJ•cm - 2 ), however, less than 90% of culturable Mycobacterium were removed. The removal efficiencies of viable E. coli, Salmonella and Mycobacterium were low. Q-RT-PCR seemed to be a promising method for evaluating viable microorganisms in samples. Besides, pathogenic bacteria entered into VBNC state at

  14. Effect of hand wash agents on controlling the transmission of pathogenic bacteria from hands to food.

    Science.gov (United States)

    Fischler, George E; Fuls, Janice L; Dail, Elizabeth W; Duran, Melani H; Rodgers, Nancy D; Waggoner, Andrea L

    2007-12-01

    The goals of this study were to evaluate the effectiveness of two hand wash regimens in reducing transient bacteria on the skin following a single hand wash and the subsequent transfer of the bacteria to a ready-to-eat food item, freshly cut cantaloupe melon. The number of bacteria recovered from hands and the quantity transferred to the melon were significantly less following the use of an antibacterial soap compared with plain soap. The antimicrobial soap achieved > 3-log reductions versus Escherichia coli and 3.31- and 2.83-log reductions versus Shigella flexneri. The plain soap failed to achieve a 2-log reduction against either organism. The bacteria recovered from the melon handled by hands treated with antimicrobial hand soap averaged 2 log. Melon handled following hand washing with plain soap had > 3 log bacteria in the experiments. Based on previously published feeding studies, an infection rate in the range of approximately 15 to 25% would be expected after ingesting melon containing 2 log CFU compared with ingesting greater than the 3 log transferred from hands washed with plain soap, which would result in a higher infection attack rate of 50 to 80%. The data thus demonstrate there is a greater potential to reduce the transmission and acquisition of disease through the use of an antimicrobial hand wash than through the use of plain soap.

  15. Recent Advancements in Nanobioassays and Nanobiosensors for Foodborne Pathogenic Bacteria Detection.

    Science.gov (United States)

    Chen, Jing; Park, Bosoon

    2016-06-01

    Bacterial pathogens are one of the leading causes of food safety incidents and product recalls worldwide. Timely detection and identification of microbial contamination in agricultural and food products is crucial for disease prevention and outbreak investigation. In efforts to improve and/or replace time-consuming and laborious "gold standards" for pathogen detection, numerous alternative rapid methods have been proposed in the past 15 years, with a trend toward incorporating nanotechnology and nanomaterials in food pathogen detection. This article is a review of the use of nanotechnology in various detection and sample preparation techniques and advancements in nanotechnology applications in food matrices. Some practical considerations in nanobioassay design are discussed, and the gaps between research status quo and market demands are identified.

  16. Viruses versus bacteria-novel approaches to phage therapy as a tool against multidrug-resistant pathogens.

    Science.gov (United States)

    Viertel, Tania Mareike; Ritter, Klaus; Horz, Hans-Peter

    2014-09-01

    Bacteriophage therapy (the application of phages to treat bacterial infections) has a tradition dating back almost a century, but interest in phage therapy slowed down in the West when antibiotics were discovered. With the emerging threat of infections caused by multidrug-resistant bacteria and scarce prospects of newly introduced antibiotics in the future, phages are currently being reconsidered as alternative therapeutics. Conventional phage therapy uses lytic bacteriophages for treatment and recent human clinical trials have revealed encouraging results. In addition, several other modern approaches to phages as therapeutics have been made in vitro and in animal models. Dual therapy with phages and antibiotics has resulted in significant reductions in the number of bacterial pathogens. Bioengineered phages have overcome many of the problems of conventional phage therapy, enabled targeted drug delivery or reversed the resistance of drug-resistant bacteria. The use of enzymes derived from phages, such as endolysin, as therapeutic agents has been efficient in the elimination of Gram-positive pathogens. This review presents novel strategies for phage-related therapies and describes our current knowledge of natural bacteriophages within the human microbiome. Our aim is to provide an overview of the high number of different methodological concepts, thereby encouraging further research on this topic, with the ultimate goal of using phages as therapeutic or preventative medicines in daily clinical practice.

  17. The Wnt/β-catenin signaling pathway controls the inflammatory response in infections caused by pathogenic bacteria.

    Science.gov (United States)

    Silva-García, Octavio; Valdez-Alarcón, Juan J; Baizabal-Aguirre, Víctor M

    2014-01-01

    Innate immunity against pathogenic bacteria is critical to protect host cells from invasion and infection as well as to develop an appropriate adaptive immune response. During bacterial infection, different signaling transduction pathways control the expression of a wide range of genes that orchestrate a number of molecular and cellular events to eliminate the invading microorganisms and regulate inflammation. The inflammatory response must be tightly regulated because uncontrolled inflammation may lead to tissue injury. Among the many signaling pathways activated, the canonical Wnt/β-catenin has been recently shown to play an important role in the expression of several inflammatory molecules during bacterial infections. Our main goal in this review is to discuss the mechanism used by several pathogenic bacteria to modulate the inflammatory response through the Wnt/β-catenin signaling pathway. We think that a deep insight into the role of Wnt/β-catenin signaling in the inflammation may open new venues for biotechnological approaches designed to control bacterial infectious diseases.

  18. Effects of Achyrocline satureioides Inflorescence Extracts against Pathogenic Intestinal Bacteria: Chemical Characterization, In Vitro Tests, and In Vivo Evaluation

    Directory of Open Access Journals (Sweden)

    Karla Suzana Moresco

    2017-01-01

    Full Text Available Three Achyrocline satureioides (AS inflorescences extracts were characterized: (i a freeze-dried extract prepared from the aqueous extractive solution and (ii a freeze-dried and (iii a spray-dried extract prepared from hydroethanol extractive solution (80% ethanol. The chemical profile, antioxidant potential, and antimicrobial activity against intestinal pathogenic bacteria of AS extracts were evaluated. In vitro antioxidant activity was determined by the total reactive antioxidant potential (TRAP assay. In vivo analysis and characterization of intestinal microbiota were performed in male Wistar rats (saline versus treated animals with AS dried extracts by high-throughput sequencing analysis: metabarcoding. Antimicrobial activity was tested in vitro by the disc diffusion tests. Moisture content of the extracts ranged from 10 to 15% and 5.7 to 17 mg kg−1 of fluorine. AS exhibited antioxidant activity, especially in its freeze-dried form which also exhibited a wide spectrum of antimicrobial activity against intestinal pathogenic bacteria greater than those observed by the antibiotic, amoxicillin, when tested against Bacillus cereus and Staphylococcus aureus. Antioxidant and antimicrobial activities of AS extracts seemed to be positively correlated with the present amount of flavonoids. These findings suggest a potential use of AS as a coadjuvant agent for treating bacterial-induced intestinal diseases with high rates of antibiotic resistance.

  19. Antagonistic and Quantitative Assessment of Indigenous Lactic acid Bacteria in Different Varieties of Ogi against Gastrointestinal Pathogens.

    Science.gov (United States)

    Afolayan, Ayorinde Oluwatobiloba; Ayeni, Funmilola Abidemi; Ruppitsch, Werner

    2017-01-01

    Ogi is a popular fermented cereal gruel consumed mainly in the western part of Nigeria. Traditionally, uncooked Ogi is normally administered to diarrhoea patients to reduce the frequency of stooling. This study was therefore undertaken to identify, quantify and determine the antimicrobial properties of lactic acid bacteria (LAB) isolated from Ogi. The Ogi samples (Yellow, white, sorghum) were obtained from different market in Ibadan, Nigeria and Ogi control (cooked, uncooked and Omidun) were prepared with the viable counts of bacteria monitored over 5 days period. LAB were isolated from the varieties and identified by partial sequencing of 16S rRNA gene. The antimicrobial activities of the cell free supernatant (CFS) and the viable cells of the isolated LAB against Escherichia coli EC004, Salmonella sp. SS11, Shigella sp. SS10 were investigated by agar diffusion assay, agar overlay method, and coculture growth studies. Omidun had the highest LAB count while cooked ogi has the lowest LAB count. Weissella paramesenteroides , L. brevis, L. rossiae, L. fermentum, L. plantarum, Acetobacter pasteurianus, Paenibacillus sp. and Bacillus sp. were isolated from Ogi in this study. Large zone of inhibition (11≤x≤20) was observed with CFS against Salmonella sp. SS11 and Shigella sp. SS10 and also the overlay method. Coculture studies of Weissella paramesenteroides, Lactobacillus fermentum, and L. plantarum with Salmonella sp. SS11 showed a 5-8 log reduction of the pathogens' growth after 24 hours as compared with the control. Ogi and its contents have antimicrobial properties against pathogenic organisms.

  20. Evaluation of Lactic Acid Bacteria Isolated from Fermented Plant Products for Antagonistic Activity Against Urinary Tract Pathogen Staphylococcus saprophyticus.

    Science.gov (United States)

    Tsai, Cheng-Chih; Lai, Tzu-Min; Lin, Pei-Pei; Hsieh, You-Miin

    2017-08-05

    Urinary tract infections (UTIs) are the most common infectious diseases in infants and the elderly; they are also the most common among nosocomial infections. The treatment of UTIs usually involves a short-term course of antibiotics. The purpose of this study was to identify the strains of lactic acid bacteria (LAB) that can inhibit the urinary tract pathogen Staphylococcus saprophyticus, as alternatives to antibiotics. In this study, we collected 370 LAB strains from fermented plant products and reference strains from the Bioresources Collection and Research Center (BCRC). Using spent culture supernatants (SCS), we then screened these LAB strains with for antimicrobial effects on urinary tract pathogens by the well-diffusion assay. Seven LAB strains-PM2, PM68, PM78, PM201, PM206, PM229, and RY2-exhibited inhibitory activity and were evaluated for anti-growth activity against urinary tract pathogens by the co-culture inhibition assay. Anti-adhesion and anti-invasion activities against urinary tract pathogens were evaluated using the SV-HUC-1 urothelial cell cultures. The results revealed that the survival rate of S. saprophyticus ranged from 0.9-2.96%, with the pH continuously decreasing after co-culture with LAB strains for 4 h. In the competitive adhesion assay, the exclusion and competition groups performed better than the displacement group. In the SV-HUC-1 cell invasion assay, PM201, PM206, PM229, and RY2 were found to inhibit the invasion of SV-HUC-1 cells by S. saprophyticus BCRC 10786. To conclude, RY2, PM229, and PM68 strains exhibited inhibitory activity against the urinary tract pathogen S. saprophyticus.

  1. ANTIBACTERIAL ACTIVITY OF THREE MEDICINAL PLANTS OF KUMAUN HIMALAYA AGAINST SOME PATHOGENIC BACTERIA

    Directory of Open Access Journals (Sweden)

    S. C. SATI

    2015-11-01

    Full Text Available The antibacterial property of methanol, ethanol and hexane extracts of Berberis aristata, Chenopodium ambrosioides and Tinospora cordifolia grown in Kumaun Himalayan were investigated against some pathogenic gram positive and gram negative bacterial strains (Bacillus subtilis, Agrobacterium tumefaciens, Escherichia coli, Xanthomonas phaseoli and Erwinia chrysanthemi using disc diffusion method. Methanol extract of B. aristata was found with highest inhibitory activity against E. chrysanthemi (ZOI, 11±0.3mm. Whereas lowest inhibition was recorded in ethanolic extract of B. aristata against E. coli. The hexane extract of B. aristata and methanolic extract of C. ambrosioides were found totally inactive against all the pathogens tested.

  2. Dual Enlargement of Gold Nanoparticles: From Mechanism to Scanometric Detection of Pathogenic Bacteria

    DEFF Research Database (Denmark)

    Cao, Cuong; Gontard, Lionel Cervera; Le Ly, Tram Thuy

    2011-01-01

    capturing the target bacteria, gold‐tagged immunoprobes are added to create a signal on a solid substrate. The signal is then amplified by the dual enlargement process, resulting in a strong color intensity that can easily be recognized by the unaided eye, or measured by an inexpensive flatbed scanner...

  3. Antimicrobial Activity of a Cationic Guanidine Compound against Two Pathogenic Oral Bacteria

    Directory of Open Access Journals (Sweden)

    E. Escamilla-García

    2017-01-01

    Full Text Available This study evaluated the potential antimicrobial properties of a polyguanidine (CatDex on two oral bacteria. Chlorhexidine gluconate 1340 μmoL L−1 (CHX 0.12% was used as control. Streptococcus mutans (S. mutans and Porphyromonas gingivalis (P. gingivalis were grown in BHI media. Bacterial sensitivity and antimicrobial activity were determined by the minimum inhibitory concentration (MIC and Kirby-Bauer methods. To study side effects, that is, toxicity, dental pulp stem cells (DPSCs were used. Fluorometric cytotoxicity and confocal microscopy assays were used in order to test cell viability. CatDex inhibited growth of S. mutans at all concentrations and growth of P. gingivalis at all concentrations except 25 μmoL L−1. The MIC of CatDex was 50 μmoL L−1 for both S. mutans and P. gingivalis. The inhibition of bacteria exposed for 8 h at 50 μmoL L−1 of CatDex exhibited increased antimicrobial activity over time, with 91% inhibition in both bacteria. The antimicrobial activities of CatDex and CHX were similar when tested on two common bacteria. CatDex was significantly less toxic to DPSCs. CatDex toxicity depended on time and not on concentration. With regard to clinical relevance, CatDex may have potential as a novel antimicrobial agent. Further studies are in progress.

  4. Diversity and natural functions of antibiotics produced by beneficial and plant pathogenic bacteria.

    Science.gov (United States)

    Raaijmakers, Jos M; Mazzola, Mark

    2012-01-01

    Soil- and plant-associated environments harbor numerous bacteria that produce antibiotic metabolites with specific or broad-spectrum activities against coexisting microorganisms. The function and ecological importance of antibiotics have long been assumed to yield a survival advantage to the producing bacteria in the highly competitive but resource-limited soil environments through direct suppression. Although specific antibiotics may enhance producer persistence when challenged by competitors or predators in soil habitats, at subinhibitory concentrations antibiotics exhibit a diversity of other roles in the life history of the producing bacteria. Many processes modulated by antibiotics may be inherently critical to the producing bacterium, such as the acquisition of substrates or initiation of developmental changes that will ensure survival under stressful conditions. Antibiotics may also have roles in more complex interactions, including in virulence on host plants or in shaping the outcomes of multitrophic interactions. The innate functions of antibiotics to producing bacteria in their native ecosystem are just beginning to emerge, but current knowledge already reveals a breadth of activities well beyond the historical perspective of antibiotics as weaponry in microbial conflicts.

  5. Diversity and natural functions of antibiotics produced by beneficial and plant pathogenic bacteria

    NARCIS (Netherlands)

    Raaijmakers, J.M.; Mazzola, M.

    2012-01-01

    Soil- and plant-associated environments harbor numerous bacteria that produce antibiotic metabolites with specific or broad-spectrum activities against coexisting microorganisms. The function and ecological importance of antibiotics have long been assumed to yield a survival advantage to the produci

  6. Diversity and natural functions of antibiotics produced by beneficial and plant pathogenic bacteria

    NARCIS (Netherlands)

    Raaijmakers, J.M.; Mazzola, M.

    2012-01-01

    Soil- and plant-associated environments harbor numerous bacteria that produce antibiotic metabolites with specific or broad-spectrum activities against coexisting microorganisms. The function and ecological importance of antibiotics have long been assumed to yield a survival advantage to the produci

  7. Copper, gold, and silver decorated magnetic core-polymeric shell nanostructures for destruction of pathogenic bacteria

    Science.gov (United States)

    Padervand, Mohsen; Karanji, Ahmad Kiani; Elahifard, Mohammad Reza

    2017-05-01

    Fe3O4 magnetic nanoparticles (MNPs) were prepared by co-precipitation method. The nanoparticles were silica coated using TEOS, and then modified by the polymeric layers of polypropylene glycol (PPG) and polyethylene glycol (PEG). Finally, the core-shell samples were decorated with Ag, Au, and Cu nanoparticles. The products were characterized by vibrating sample magnetometry (VSM), TGA, SEM, XRD, and FTIR methods. The antibacterial activity of the prepared samples was evaluated in inactivation of E. coli and S. aureus microorganisms, representing the Gram-negative and Gram-positive species, respectively. The effect of solid dosage, bacteria concentration and type of polymeric modifier on the antibacterial activity was investigated. TEM images of the bacteria were recorded after the treatment time and according to the observed changes in the cell wall, the mechanism of antibacterial action was discussed. The prepared nanostructures showed high antibacterial activity against both Gram-negative and Gram-positive bacteria. This was due to the leaching of metal ions which subsequently led to the lysis of bacteria. A theoretical investigation was also done by studying the interaction of loaded metals with the nucleotide components of the microorganism DNA, and the obtained results were used to explain the experimental data. Finally, based on the observed inactivation curves, we explain the antibacterial behavior of the prepared nanostructures mathematically.

  8. Diversity and natural functions of antibiotics produced by beneficial and plant pathogenic bacteria

    NARCIS (Netherlands)

    Raaijmakers, J.M.; Mazzola, M.

    2012-01-01

    Soil- and plant-associated environments harbor numerous bacteria that produce antibiotic metabolites with specific or broad-spectrum activities against coexisting microorganisms. The function and ecological importance of antibiotics have long been assumed to yield a survival advantage to the

  9. Antibacterial activities of metabolites from Platanus occidenatalis (American sycamore) against fish pathogenic bacteria

    Science.gov (United States)

    One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentall...

  10. Antibacterial activities of metabolites from Platanus occidentalis (American sycamore) against fish pathogenic bacteria

    Science.gov (United States)

    One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentall...

  11. Identification of organic acids in Cichorium intybus inhibiting virulence-related properties of oral pathogenic bacteria

    NARCIS (Netherlands)

    Papetti, A.; Mascherpa, D.; Carazzone, C.; Stauder, M.; Spratt, D.A.; Wilson, M.; Pratten, J.; Ciric, L.; Lingström, P.; Zaura, E.; Weiss, E.; Ofek, I.; Signoretto, C.; Pruzzo, C.; Gazzani, G.

    2013-01-01

    The low molecular mass (LMM) extract of Cichorium intybus var. silvestre (red chicory) has been shown to inhibit virulence-linked properties of oral pathogens including Streptococcus mutans, Actinomyces naeslundii and Prevotella intermedia. In the present study HPLC-DAD-ESI/MS2 was used to investiga

  12. Antibacterial activity of leaves extracts of Trifolium alexandrinum Linn. against pathogenic bacteria causing tropical diseases

    Institute of Scientific and Technical Information of China (English)

    Abdul Viqar Khan; Qamar Uddin Ahmed; Indu Shukla; Athar Ali Khan

    2012-01-01

    Objective: To investigate antibacterial potential of Trifolium alexandrinum (T. alexandrinum) Linn. against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases. Methods: Non-polar and polar extracts of the leaves of T. alexandrinum i.e., hexane, dichloromethane (DCM), ethyl acetate (EtOAc), methanol (MeOH) and aqueous (AQ) extracts at five different concentrations (1, 2, 5, 10 and 15 mg/mL) were prepared to evaluate their antibacterial value. NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method. Results: Polar extracts demonstrated significant antibacterial activity against tested pathogens. EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens. While AQ plant extract inhibited the growth of sixteen of the test strains. EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains. Conclusions: The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases. Since Egyptian clover is used as a fodder plant, it could be helpful in controlling various infectious diseases associated with cattle as well.

  13. Identification of organic acids in Cichorium intybus inhibiting virulence-related properties of oral pathogenic bacteria

    NARCIS (Netherlands)

    Papetti, A.; Mascherpa, D.; Carazzone, C.; Stauder, M.; Spratt, D.A.; Wilson, M.; Pratten, J.; Ciric, L.; Lingström, P.; Zaura, E.; Weiss, E.; Ofek, I.; Signoretto, C.; Pruzzo, C.; Gazzani, G.

    2013-01-01

    The low molecular mass (LMM) extract of Cichorium intybus var. silvestre (red chicory) has been shown to inhibit virulence-linked properties of oral pathogens including Streptococcus mutans, Actinomyces naeslundii and Prevotella intermedia. In the present study HPLC-DAD-ESI/MS2 was used to

  14. Seeds of the Wild Progenitor of Maize Possess Bacteria That Antagonize Foodborne Pathogens.

    Science.gov (United States)

    Shehata, Hanan R; Griffiths, Mansel W; Raizada, Manish N

    2017-02-10

    Endophytes are microorganisms that inhabit plant tissues without causing disease. Some endophytes help their hosts to combat pathogens. Here we explored the hypothesis that the plant-derived foods consumed by humans and other animals host endophytes that also antagonize foodborne pathogens or food-rotting agents. Our laboratory previously cultured a library of bacterial endophytes from different members of the maize/corn family (Zea) including wild relatives. Here, 190 of these endophytes were screened for their ability to antagonize four foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Clostridium perfringens, and Salmonella enterica Newport) and a food spoiling agent (Pseudomonas fluorescens) using dual culture assays. Two Paenibacillus polymyxa endophytes (strains 3C6 and 3G11) were found to inhibit the growth of all five deleterious strains on agar. Using conserved polymerase chain reaction primers and sequencing, both beneficial endophytes were found to encode polymyxin genes, suggesting a potential antibacterial mechanism of action. Polymyxin production by both strains was confirmed using enzyme-linked immunosorbent assay. Strains 3C6 and 3G11 originated, respectively, from the seeds of the wild Central American maize species Zea diploperennis, and the wild ancestor of modern maize, Zea mays ssp parviglumis (Parviglumis). As the latter is the direct ancestor of modern maize, we discuss the role its endophyte(s) may have played in promoting crop domestication by suppressing foodborne pathogens and/or food-spoilage agents.

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

    Science.gov (United States)

    Antibiotics are important to equine medicine, but antibiotic-associated diarrhea (AAD) can lead to poor performance and even mortality. AAD is attributed to disruption of the hindgut microbiota, which permits proliferation of pathogenic microbes. The goal of this study was to evaluate the effects o...

  16. Toxicity of twenty-two plant essential oils against pathogenic bacteria of vegetables and mushrooms.

    Science.gov (United States)

    Todorović, Biljana; Potočnik, Ivana; Rekanović, Emil; Stepanović, Miloš; Kostić, Miroslav; Ristić, Mihajlo; Milijašević-Marčić, Svetlana

    2016-12-01

    ASBTRACT Toxicity of twenty-two essential oils to three bacterial pathogens in different horticultural systems: Xanthomonas campestris pv. phaseoli (causing blight of bean), Clavibacter michiganensis subsp. michiganensis (bacterial wilt and canker of tomato), and Pseudomonas tolaasii (causal agent of bacterial brown blotch on cultivated mushrooms) was tested. Control of bacterial diseases is very difficult due to antibiotic resistance and ineffectiveness of chemical products, to that essential oils offer a promising alternative. Minimal inhibitory and bactericidal concentrations are determined by applying a single drop of oil onto the inner side of each plate cover in macrodilution assays. Among all tested substances, the strongest and broadest activity was shown by the oils of wintergreen (Gaultheria procumbens), oregano (Origanum vulgare), and lemongrass (Cymbopogon flexuosus. Carvacrol (64.0-75.8%) was the dominant component of oregano oils, while geranial (40.7%) and neral (26.7%) were the major constituents of lemongrass oil. Xanthomonas campestris pv. phaseoli was the most sensitive to plant essential oils, being susceptible to 19 oils, while 11 oils were bactericidal to the pathogen. Sixteen oils inhibited the growth of Clavibacter michiganensis subsp. michiganensis and seven oils showed bactericidal effects to the pathogen. The least sensitive species was Pseudomonas tolaasii as five oils inhibited bacterial growth and two oils were bactericidal. Wintergreen, oregano, and lemongrass oils should be formulated as potential biochemical bactericides against different horticultural pathogens.

  17. Stenotrophomonas comparative genomics reveals genes and functions that differentiate beneficial and pathogenic bacteria.

    Science.gov (United States)

    Alavi, Peyman; Starcher, Margaret R; Thallinger, Gerhard G; Zachow, Christin; Müller, Henry; Berg, Gabriele

    2014-06-18

    In recent years, the number of human infections caused by opportunistic pathogens has increased dramatically. Plant rhizospheres are one of the most typical natural reservoirs for these pathogens but they also represent a great source for beneficial microbes with potential for biotechnological applications. However, understanding the natural variation and possible differences between pathogens and beneficials is the main challenge in furthering these possibilities. The genus Stenotrophomonas contains representatives found to be associated with human and plant host. We used comparative genomics as well as transcriptomic and physiological approaches to detect significant borders between the Stenotrophomonas strains: the multi-drug resistant pathogenic S. maltophilia and the plant-associated strains S. maltophilia R551-3 and S. rhizophila DSM14405T (both are biocontrol agents). We found an overall high degree of sequence similarity between the genomes of all three strains. Despite the notable similarity in potential factors responsible for host invasion and antibiotic resistance, other factors including several crucial virulence factors and heat shock proteins were absent in the plant-associated DSM14405T. Instead, S. rhizophila DSM14405T possessed unique genes for the synthesis and transport of the plant-protective spermidine, plant cell-wall degrading enzymes, and high salinity tolerance. Moreover, the presence or absence of bacterial growth at 37°C was identified as a very simple method in differentiating between pathogenic and non-pathogenic isolates. DSM14405T is not able to grow at this human-relevant temperature, most likely in great part due to the absence of heat shock genes and perhaps also because of the up-regulation at increased temperatures of several genes involved in a suicide mechanism. While this study is important for understanding the mechanisms behind the emerging pattern of infectious diseases, it is, to our knowledge, the first of its kind to

  18. New findings from an old pathogen: intraerythrocytic bacteria (family Anaplasmatacea) in red-backed salamanders Plethodon cinereus.

    Science.gov (United States)

    Davis, Andrew K; DeVore, Jayna L; Milanovich, Joseph R; Cecala, Kristen; Maerz, John C; Yabsley, Michael J

    2009-06-01

    During a recent study of red-backed salamanders (Plethodon cinereus), we discovered an intraerythrocytic organism typified by violet-staining, intracellular inclusions, consistent with descriptions of Cytamoeba or Aegyptianella (bacteria). Here we characterize its taxonomic status using molecular techniques and ask basic questions about its nature. Blood smears from 102 salamanders were examined from Pennsylvania, New York, and Virginia to determine prevalence, and whole blood from several infected animals was tested using a PCR which targets the 16S rRNA gene of bacteria. Phylogenetic analysis of partial 16S rRNA gene sequence (1201 bp) indicated this organism was in the order Rickettsiales and is likely a member of the family Anaplasmatacea. The organism differed from currently described taxa and was clearly differentiated from Aegyptianella pullorum of birds and "Candidatus Hemobacterium ranarum" (formally A. ranarum) of frogs. Of all salamanders, 17 (16.7%) were infected and these were significantly larger (snout-vent length) and had higher body condition scores than uninfected ones, and males were more likely to be infected than females. Erythrocytes affected by the pathogen were 5% larger than unaffected ones, but otherwise similar in morphology. Infected animals tended to have a greater number of circulating white blood cells, based on estimates from smears, indicating a nonspecific response to the pathogen by the innate immune system. Given its phylogenetic position, this pathogen is likely transmitted by an arthropod vector, and the male-biased prevalence strongly implicates trombiculid mites, which also live in leaf litter and affect male salamanders more so than females.

  19. Chemical Composition and Antibacterial Activity of Essential Oils of Tagetes minuta (Asteraceae) against Selected Plant Pathogenic Bacteria

    Science.gov (United States)

    Wagacha, John M.; Dossaji, Saifuddin F.

    2016-01-01

    The objective of this study was to determine the chemical composition and antibacterial activity of essential oils (EOs) of Tagetes minuta against three phytopathogenic bacteria Pseudomonas savastanoi pv. phaseolicola, Xanthomonas axonopodis pv. phaseoli, and Xanthomonas axonopodis pv. manihotis. The essential oils were extracted using steam distillation method in a modified Clevenger-type apparatus while antibacterial activity of the EOs was evaluated by disc diffusion method. Gas chromatography coupled to mass spectrometry (GC/MS) was used for analysis of the chemical profile of the EOs. Twenty compounds corresponding to 96% of the total essential oils were identified with 70% and 30% of the identified components being monoterpenes and sesquiterpenes, respectively. The essential oils of T. minuta revealed promising antibacterial activities against the test pathogens with Pseudomonas savastanoi pv. phaseolicola being the most susceptible with mean inhibition zone diameters of 41.83 and 44.83 mm after 24 and 48 hours, respectively. The minimum inhibitory concentrations and minimum bactericidal concentrations of the EOs on the test bacteria were in the ranges of 24–48 mg/mL and 95–190 mg/mL, respectively. These findings provide a scientific basis for the use of T. minuta essential oils as a botanical pesticide for management of phytopathogenic bacteria. PMID:27721831

  20. 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.

  1. [Evaluation of epidemic risk from pathogenic and opportunistic bacteria isolated from water of its various use types].

    Science.gov (United States)

    Zagaĭnova, A V; Talaeva, Iu G; Dmitrieva, R A; Ingel', F I; Iurchenko, V V; Artemova, T Z; Nedachin, A E; Gipp, E K; Butorina, N N; Snegirev, D V

    2010-01-01

    The investigation was concerned with wild gram-positive and gram-negative microorganisms (E. coli spp., Klebsiella spp., Salmonella spp., and the nonfermentative bacteria Pseudomonas spp.) isolated from the waters of different types, as well as museum cultures (E. coli strain 1257, E. coli strain 675, Salmonella enteritidis ATCC 5765, Staphylococcus aureus 906, and Pseudomonas aeruginosa ATCC 10145). The wild strains were isolated from water when conducting experimental and field studies; these are able to survive in the waters disinfected by various procedures (a guanidine-containing disinfectant in non-toxic concentrations; photo-activated decontamination with sensitizers; exposure to magnetic and ultrasound waves). The cytotoxic, adhesive, and invasive activities of the bacteria isolated from environmental water objects increased on their cultivation on nutrient growth media, by simulating their possible effects in man. The developed experimental approach makes it possible to estimate the hazard of potentially pathogenic bacteria in one test trial, by applying the BGM cells and may be used to assess the microbial risk.

  2. Chemical Composition and In Vitro Antibacterial Activity of Mentha spicata Essential Oil against Common Food-Borne Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Yasser Shahbazi

    2015-01-01

    Full Text Available The aim of the present study was to investigate chemical composition and antibacterial activity of essential oil from the leaf of Mentha spicata plant against common food-borne pathogenic bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli O157:H7. Chemical composition of the essential oil was identified by gas chromatography coupled with mass spectrometer detector (GC-MS. The antibacterial activity of the essential oil was evaluated by broth microdilution method and agar disk diffusion assay. According to the result of GC-MS analysis, 18 components were identified, accounting for 99.89% of the whole essential oil. The main components were carvone (78.76%, limonene (11.50%, β-bourbonene (11.23%, cis-dihydrocarveol (1.43%, trans-caryophyllene (1.04%, menthone (1.01%, menthol (1%, and terpinen-4-ol (0.99. The essential oil exhibited moderate level of antibacterial activity against all test microorganisms. In general, Gram-positive bacteria were more susceptible to M. spicata essential oil than Gram-negative bacteria. L. monocytogenes was the most sensitive of the microorganisms to the antibacterial activity of M. spicata essential oil (inhibition zone = 22 mm and MIC and MBC = 2.5 µL/mL. Based on our results, the essential oil of M. spicata plant collected from Kermanshah province, west of Iran, has a potential to be applied as antibacterial agent.

  3. 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.

  4. Chemical Composition and In Vitro Antibacterial Activity of Mentha spicata Essential Oil against Common Food-Borne Pathogenic Bacteria.

    Science.gov (United States)

    Shahbazi, Yasser

    2015-01-01

    The aim of the present study was to investigate chemical composition and antibacterial activity of essential oil from the leaf of Mentha spicata plant against common food-borne pathogenic bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli O157:H7). Chemical composition of the essential oil was identified by gas chromatography coupled with mass spectrometer detector (GC-MS). The antibacterial activity of the essential oil was evaluated by broth microdilution method and agar disk diffusion assay. According to the result of GC-MS analysis, 18 components were identified, accounting for 99.89% of the whole essential oil. The main components were carvone (78.76%), limonene (11.50%), β-bourbonene (11.23%), cis-dihydrocarveol (1.43%), trans-caryophyllene (1.04%), menthone (1.01%), menthol (1%), and terpinen-4-ol (0.99). The essential oil exhibited moderate level of antibacterial activity against all test microorganisms. In general, Gram-positive bacteria were more susceptible to M. spicata essential oil than Gram-negative bacteria. L. monocytogenes was the most sensitive of the microorganisms to the antibacterial activity of M. spicata essential oil (inhibition zone = 22 mm and MIC and MBC = 2.5 µL/mL). Based on our results, the essential oil of M. spicata plant collected from Kermanshah province, west of Iran, has a potential to be applied as antibacterial agent.

  5. Screening of marine seaweeds for bioactive compound against fish pathogenic bacteria and active fraction analysed by gas chromatography– mass spectrometry

    Directory of Open Access Journals (Sweden)

    Rajasekar Thirunavukkarasu

    2014-05-01

    Full Text Available Objective: To isolate bioactive molecules from marine seaweeds and check the antimicrobial activity against the fish pathogenic bacteria. Methods: Fresh marine seaweeds Gracilaria edulis, Kappaphycus spicifera, Sargassum wightii (S. wightii were collected. Each seaweed was extracted with different solvents. In the study, test pathogens were collected from microbial type culture collection. Antibacterial activity was carried out by using disc diffusion method and minimum inhibition concentration (MIC was calculated. Best seaweed was analysed by fourier transform infrared spectroscopy. The cured extract was separated by thin layer chromatography (TLC. Fraction was collected from TLC to check the antimicrobial activity. Best fraction was analysed by gas chromatography mass spectrometer (GCMS. Results: Based on the disc diffusion method, S. wightii showed a better antimicrobial activity than other seaweed extracts. Based on the MIC, methanol extract of S. wightii showed lower MIC than other solvents. S. wightii were separated by TLC. In this TLC, plate showed a two fraction. These two fractions were separated in preparative TLC and checked for their antimicrobial activity. Fraction 2 showed best MIC value against the tested pathogen. Fraction 2 was analysed by GCMS. Based on the GCMS, fraction 2 contains n-hexadecanoic acid (59.44%. Conclusions: From this present study, it can be concluded that S. wightii was potential sources of bioactive compounds.

  6. DNA Delivery and Genomic Integration into Mammalian Target Cells through Type IV A and B Secretion Systems of Human Pathogens

    Directory of Open Access Journals (Sweden)

    Dolores L. Guzmán-Herrador

    2017-08-01

    Full Text Available We explore the potential of bacterial secretion systems as tools for genomic modification of human cells. We previously showed that foreign DNA can be introduced into human cells through the Type IV A secretion system of the human pathogen Bartonella henselae. Moreover, the DNA is delivered covalently attached to the conjugative relaxase TrwC, which promotes its integration into the recipient genome. In this work, we report that this tool can be adapted to other target cells by using different relaxases and secretion systems. The promiscuous relaxase MobA from plasmid RSF1010 can be used to deliver DNA into human cells with higher efficiency than TrwC. MobA also promotes DNA integration, albeit at lower rates than TrwC. Notably, we report that DNA transfer to human cells can also take place through the Type IV secretion system of two intracellular human pathogens, Legionella pneumophila and Coxiella burnetii, which code for a distantly related Dot/Icm Type IV B secretion system. This suggests that DNA transfer could be an intrinsic ability of this family of secretion systems, expanding the range of target human cells. Further analysis of the DNA transfer process showed that recruitment of MobA by Dot/Icm was dependent on the IcmSW chaperone, which may explain the higher DNA transfer rates obtained. Finally, we observed that the presence of MobA negatively affected the intracellular replication of C. burnetii, suggesting an interference with Dot/Icm translocation of virulence factors.

  7. In vitro Antibacterial activity of Pimpinella anisum fruit extracts against some pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    A.Akhtar

    Full Text Available The antibacterial activities of the aqueous, 50% (v/v methanol,acetone and petroleum ether extracts of Pimpinella anisum (L fruits were studied. The extracts of Pimpinella anisum were tested in vitro against 4 bacterial species by the disc diffusion method. Staphylococcus aureus (MTCC 96, Streptococcus pyogenes (MTCC 442, Escherchia coli (MTCC 723 and Klebsiella Pneumoniae (MTCC 109 were used in this investigation. Only aqueous and 50% (v/v methanol extract exhibited fair antibacterial activity against all the test bacteria whereas acetone and petroleum ether extract were not observed to inhibit the growth of any of the test bacteria under study. [Veterinary World 2008; 1(9.000: 272-274

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

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. In vitro antibacterial activity of selected medicinal plants traditionally used in Vietnam against human pathogenic bacteria

    OpenAIRE

    Vu, Thuy Thu; Kim, Hyungrok; Tran, Vu Khac; Le Dang, Quang; Nguyen, Hoa Thi; Kim, Hun; Kim, In Seon; Choi, Gyung Ja; Kim, Jin-Cheol

    2016-01-01

    Background Medicinal plants are widely used for the treatment of different infectious diseases. Infectious diseases caused by bacteria have a large impact on public health. This study aimed to determine the in vitro antibacterial activity of the medicinal plants traditionally used in Vietnam against the bacterial strains associated with infectious diseases. Methods Methanol extracts of twelve Vietnamese medicinal plants were tested for their antibacterial activity against five bacterial speci...

  11. Fighting Off Wound Pathogens in Horses with Honeybee Lactic Acid Bacteria

    OpenAIRE

    Olofsson, Tobias C.; Butler, Éile; Lindholm, Christina; Nilson, Bo; Michanek, Per; Vásquez, Alejandra

    2016-01-01

    In the global perspective of antibiotic resistance, it is urgent to find potent topical antibiotics for the use in human and animal infection. Healing of equine wounds, particularly in the limbs, is difficult due to hydrostatic factors and exposure to environmental contaminants, which can lead to heavy bio-burden/biofilm formation and sometimes to infection. Therefore, antibiotics are often prescribed. Recent studies have shown that honeybee-specific lactic acid bacteria (LAB), involved in ho...

  12. Engineering the stereochemistry of cephalosporin for specific detection of pathogenic carbapenemase-expressing bacteria.

    Science.gov (United States)

    Shi, Haibin; Cheng, Yunfeng; Lee, Kyung Hyun; Luo, Robert F; Banaei, Niaz; Rao, Jianghong

    2014-07-28

    Reported herein is the design of fluorogenic probes specific for carbapenem-resistant Enterobacteriaceae (CRE) and they were designed based on stereochemically modified cephalosporin having a 6,7-trans configuration. Through experiments using recombinant β-lactamase enzymes and live bacterial species, these probes demonstrate the potential for use in the specific detection of carbapenemases, including metallo-β-lactamases in active bacterial pathogens.

  13. Modelling antagonic effect of lactic acid eacteria supernatants on some pathogenic bacteria

    OpenAIRE

    2009-01-01

    This work presents a statistical model of survival analysis for three pathogenic bacterial strains (Escherichia coli, Listeria monocytogenes and Staphylococcus aureus), when treated with neutralized and non-neutralized filtered supernatants broth from cultures of Lactobacillus acidhophilus, Lactobacillus rhamnosus and Lactobacillus sake. Survival analysis is a method employed to determine the period of time from an initial stage up to the occurrence of a particular event of interest, as death...

  14. INHIBITION OF PATHOGENS BY SPOROGENIC BACTERIA ISOLATED FROM HONEY OF Melipona sp. (APIDAE: APINAE: MELIPONINI

    Directory of Open Access Journals (Sweden)

    KELY DAMIANA NOVAES DA SILVA

    2016-01-01

    Full Text Available The aim of this study was to isolate sporogenic bacteria from the honey of stingless bees Melipona sp., in dry forest, and to evaluate their antagonistic potential for medicinal employment purposes and animal production. The honey samples were collected in Serra Talhada - PE, where honey was taken from four different hives (in triplicate, totaling 12 samples. The samples were diluted and subjected to 80 ºC for 20 minutes to eliminate vegetative cells. The dilutions were plated onto nutrient agar and incubated at 30 ºC for 72 hours. Then the colony forming units (CFU were quantified. The samples were also plated onto malt agar and Sabouraud agar, and incubated at 30 ºC for 14 days for the growth of yeast and molds. Total and fecal coliforms were quantified by the most probable number method (MPN. Seven isolates (I of sporogenic bacteria ( Bacillus were obtained, however only four showed probiotic potential. Isolate I - 5 showed the greatest probiotic potential and inhibited the growth of Escherichia coli , Klebsiella sp., Pseudomonas aeruginosa, Salmonella sp., and Staphylococcus aureus . The growth of the Sarcina sp. was not inhibited by any isolate. No yeast, molds or coliforms were found. The Melipona sp. honey is a source of spore - forming bacteria and is antagonistic to microorganisms that contaminate honey. It has good microbiological quality.

  15. In vitro antimicrobial activity of ZnO based glass-ceramics against pathogenic bacteria.

    Science.gov (United States)

    Riaz, Madeeha; Zia, Rehana; Saleemi, Farhat; Ikram, Hafeez; Bashir, Farooq

    2015-12-01

    The antibacterial activity of ZnO (0-15.53 mol%) based SiO2-CaO-P2O5-Na2O-CaF2 bioactive glass-ceramics synthesized by controlled crystallisation were studied against eight micro-organisms using modified Kirby Bauer method. The antibacterial activity of the specimens was statistically evaluated using one-way analysis of variance and P < 0.05 was used as the level of significance. In vitro dissolution tests were performed in stimulated body fluid for 48 h at 37 °C for different time intervals to correlate the dissolution behaviour of test samples with antibacterial effects. The results illustrate that specimen BZn15.53 having the highest concentration of ZnO (15.53 mol%) demonstrated the strongest effect against Staph.aureus, S. epidermidis, B. subtilis and K. pneumonia. The effectiveness of BZn15.53 in inhibiting bacteria was due to accumulation of Zn(+2) ions around the surface of the bacteria cell release that caused the death of the cell, besides the presence of hydroxyapatite phase was also responsible for damaging the cell membrane of bacteria.

  16. Autoinducer-2 of the fire blight pathogen Erwinia amylovora and other plant-associated bacteria.

    Science.gov (United States)

    Mohammadi, Mojtaba; Geider, Klaus

    2007-01-01

    Autoinducers are important for cellular communication of bacteria. The luxS gene has a central role in the synthesis of autoinducer-2 (AI-2). The gene was identified in a shotgun library of Erwinia amylovora and primers designed for PCR amplification from bacterial DNA. Supernatants of several Erwinia amylovora strains were assayed for AI-2 activity with a Vibrio harveyi mutant and were positive. Many other plant-associated bacteria also showed AI-2 activity such as Erwinia pyrifoliae and Erwinia tasmaniensis. The luxS genes of several bacteria were cloned, sequenced, and complemented Escherichia coli strain DH5alpha and a Salmonella typhimurium mutant, both defective in luxS, for synthesis of AI-2. Assays to detect AI-2 activity in culture supernatants of several Pseudomonas syringae pathovars failed, which may indicate the absence of AI-2 or synthesis of another type. Several reporter strains did not detect synthesis of an acyl homoserine lactone (AHL, AI-1) by Erwinia amylovora, but confirmed AHL-synthesis for Erwinia carotovora ssp. atroseptica and Pantoea stewartii.

  17. Bactericidal Effect of Pterostilbene Alone and in Combination with Gentamicin against Human Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Wee Xian Lee

    2017-03-01

    Full Text Available The antibacterial activity of pterostilbene in combination with gentamicin against six strains of Gram-positive and Gram-negative bacteria were investigated. The minimum inhibitory concentration and minimum bactericidal concentration of pterostilbene were determined using microdilution technique whereas the synergistic antibacterial activities of pterostilbene in combination with gentamicin were assessed using checkerboard assay and time-kill kinetic study. Results of the present study showed that the combination effects of pterostilbene with gentamicin were synergistic (FIC index < 0.5 against three susceptible bacteria strains: Staphylococcus aureus ATCC 25923, Escherichia coli O157 and Pseudomonas aeruginosa 15442. However, the time-kill study showed that the interaction was indifference which did not significantly differ from the gentamicin treatment. Furthermore, time-kill study showed that the growth of the tested bacteria was completely attenuated with 2 to 8 h treatment with 0.5 × MIC of pterostilbene and gentamicin. The identified combinations could be of effective therapeutic value against bacterial infections. These findings have potential implications in delaying the development of bacterial resistance as the antibacterial effect was achieved with the lower concentrations of antibacterial agents.

  18. Bactericidal Effect of Pterostilbene Alone and in Combination with Gentamicin against Human Pathogenic Bacteria.

    Science.gov (United States)

    Lee, Wee Xian; Basri, Dayang Fredalina; Ghazali, Ahmad Rohi

    2017-03-17

    The antibacterial activity of pterostilbene in combination with gentamicin against six strains of Gram-positive and Gram-negative bacteria were investigated. The minimum inhibitory concentration and minimum bactericidal concentration of pterostilbene were determined using microdilution technique whereas the synergistic antibacterial activities of pterostilbene in combination with gentamicin were assessed using checkerboard assay and time-kill kinetic study. Results of the present study showed that the combination effects of pterostilbene with gentamicin were synergistic (FIC index < 0.5) against three susceptible bacteria strains: Staphylococcus aureus ATCC 25923, Escherichia coli O157 and Pseudomonas aeruginosa 15442. However, the time-kill study showed that the interaction was indifference which did not significantly differ from the gentamicin treatment. Furthermore, time-kill study showed that the growth of the tested bacteria was completely attenuated with 2 to 8 h treatment with 0.5 × MIC of pterostilbene and gentamicin. The identified combinations could be of effective therapeutic value against bacterial infections. These findings have potential implications in delaying the development of bacterial resistance as the antibacterial effect was achieved with the lower concentrations of antibacterial agents.

  19. Shigella IpaH Family Effectors as a Versatile Model for Studying Pathogenic Bacteria.

    Science.gov (United States)

    Ashida, Hiroshi; Sasakawa, Chihiro

    2015-01-01

    Shigella spp. are highly adapted human pathogens that cause bacillary dysentery (shigellosis). Via the type III secretion system (T3SS), Shigella deliver a subset of virulence proteins (effectors) that are responsible for pathogenesis, with functions including pyroptosis, invasion of the epithelial cells, intracellular survival, and evasion of host immune responses. Intriguingly, T3SS effector activity and strategies are not unique to Shigella, but are shared by many other bacterial pathogens, including Salmonella, Yersinia, and enteropathogenic Escherichia coli (EPEC). Therefore, studying Shigella T3SS effectors will not only improve our understanding of bacterial infection systems, but also provide a molecular basis for developing live bacterial vaccines and antibacterial drugs. One of Shigella T3SS effectors, IpaH family proteins, which have E3 ubiquitin ligase activity and are widely conserved among other bacterial pathogens, are very relevant because they promote bacterial survival by triggering cell death and modulating the host immune responses. Here, we describe selected examples of Shigella pathogenesis, with particular emphasis on the roles of IpaH family effectors, which shed new light on bacterial survival strategies and provide clues about how to overcome bacterial infections.

  20. Impact of Moringa aqueous extract on pathogenic bacteria and fungi in vitro

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    Latifa A. Al_husnan

    2016-12-01

    Full Text Available Moringa peregrine have many benefits. In this study aqueous extract of Moringa plant inhibited the activity of these bacteria which include Bacillus cereus; Staphylococcus aureus; Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli; Enterococcus cloacae; Salmonella typhi and; Proteus vulgaris. Moringa extracts has shown an impact on the growth of bacteria on the Blood with inhibition zone variable (23.5 ± 0.45 to 12.5 ± 0.50 mm according to the type of bacteria. The mean growth inhibition percentages were 85.9 ± 0.42 to 65.3 ± 0.34 nm against all tested bacteria. As regards to fungi, high potency extract displayed zones of inhibition of ⩾10 mm, moderate potent extracts gave zones of inhibition between <10 and 9 mm. The results indicated that, Moringa aqueous extract played variable antifungal activity ranged from high (18 ± 0.54 mm, moderate (13.2 ± 0.58 mm and low (6.6 ± 0.47 mm. The inhibition zones diameter in millimeters against A. niger, A. flavus, P. italicum, F. oxysporum, R. stolonifer, Alternaria sp., C. albicans, C. parapsilosis were 15.2 ± 0.52, 12.4 ± 0.55, 10.5 ± 0.26, 9.4 ± 0.71, 13.2 ± 0.58, 6.6 ± 0.47, 12 ± 0.44 and 18 ± 0.54, respectively. On the other hand, the mean inhibition of growth (as percentages were 75.2 ± 0.55, 59.4 ± 0.75, 58.2 ± 0.63, 46.5 ± 0.63, 62.5 ± 0.77, 24.5 ± 0.65, 20.3 ± 0.75 and 80.00 ± 0.70% respectively. Thus, the aqueous extract of Moringa leaves showed antimicrobial activity against tested bacteria, fungi and yeasts at different concentrations.

  1. Elimination of pathogenic bacteria in sewage sludge during the solar drying; Eliminacion de bacterias patogenas en lodos residuales durante el secado solar

    Energy Technology Data Exchange (ETDEWEB)

    Cota Espericueta, Alma Delia; Ponce Corral, Carlos [Instituto de Ciencias Biomedicas, Universidad Autonoma de Ciudad Juarez, Ciudad Juarez, Chihuahua, (Mexico)

    2008-11-15

    This paper describes the performance of a solar dryer capable of bacterial pathogen removal from the physicochemical sludge of the main wastewater treatment plant for Ciudad Juarez, Mexico. The solar setup was proposed as an alternative solution, technically feasible, for reducing the volume of the 135 tons of sludge produced per day in this plant. The experimental-greenhouse prototype has a 4.5 m{sup 2} collection area, a 1 m{sup 3}-drying bed, and automatic systems for ventilation, extraction, and data acquisition. The automatic operation was controlled by temperature and humidity differences between internal and external conditions. Global solar radiation, pH and water content of the sludge were monitored. The overall effectiveness of the solar dryer was determined by assessing thermal and microbiological performance. Water content in sludge during the process was used as an indicator of thermal effectiveness. The microbiological elimination was quantified at different residence times considering two contamination indicators: faecal coliforms and Salmonella spp. Quantification of the pathogenic microorganisms was carried out by the multiple-tube fermentation technique presented in the Mexican regulation NOM-004-SEMARNAT-2002. The thermal results related to the water content showed an exponential decay that achieved up to a 99 % reduction. Regarding microbiological removal effectiveness, there was a strong dependence between the number of bacteria present and the water content in the sludge. As a consequence, with the removal of 92 % of water, it was verified that the elimination of faecal coliforms fell from 3.8x10{sup 6} to 1.6 MPN per gram of dried sludge; and for Salmonella spp. the reduction was from 1.5x10{sup 1}3 to 1.9x10{sup 3} MPN per gram of dried sludge. [Spanish] La presente investigacion describe el desempeno de un secador solar con respecto a la eliminacion de bacterias patogenas contenidas en lodos fisicoquimicos provenientes de la principal

  2. Foodborne and waterborne pathogenic bacteria in selected Organisation for Economic Cooperation and Development (OECD) countries.

    Science.gov (United States)

    Curtis, Dennis; Hill, Arthur; Wilcock, Anne; Charlebois, Sylvain

    2014-10-01

    The World Ranking Food Safety Performance reports by Charlebois in 2008 and 2010 importantly stimulated international discussion and encouraged efforts to establish realistic international benchmarks for food safety performance among Organisation for Economic Cooperation and Development (OECD) countries. This paper presents the international incidence of 5 common foodborne pathogens and describes the challenges of comparing international data. Data were compiled from surveillance authorities in the countries, such as the Natl. Notifiable Diseases Surveillance System of Australia; the Canadian Notifiable Diseases Surveillance System; the European Food Safety Authority, EFSA; the Ministry of Health, Labour and Welfare of Japan; New Zealand Food Safety Authority; and the U.S. Center for Disease Control and Prevention. The highest average rates in cases per 100000 people over the 12-y period from 2000 to 2011 for Campylobacter spp. (237.47), Salmonella spp. (67.08), Yersinia spp. (12.09), Verotoxigenic/Shiga toxin producing Escherichia coli (3.38), and Listeria monocytogenes (1.06) corresponded, in order, to New Zealand, Belgium, Finland, Canada, and Denmark. Comparatively, annual average rates for these 5 pathogens showed an increase over the 12-y period in 28%, 17%, 14%, 50%, and 6% of the countries for which data were available. Salmonella spp. showed a decrease in 56% of the countries, while incidence of L. monocytogenes was constant in most countries (94%). Variable protocols for monitoring incidence of pathogens among OECD countries remain. Nevertheless, there is evidence of sufficient standardization of monitoring protocols such as the European Surveillance System, which has contributed to reduce this gap. © 2014 Institute of Food Technologists®

  3. Fate of Pathogenic Bacteria Associated with Production of Pickled Sausage by Using a Cold Fill Process.

    Science.gov (United States)

    Gaydos, Nelson J; Cutter, Catherine N; Campbell, Jonathan A

    2016-10-01

    Preservation by pickling has been used for many years to extend the shelf life of various types of food products. By storing meat products in a brine solution containing an organic acid, salt, spices, as well as other preservatives, the pH of the product is reduced, thus increasing the safety and shelf life of the product. Pickling may involve the use of heated brines to further add to the safety of the food product. When precooked, ready-to-eat (RTE) sausages are pickled with a heated brine solution, the process is referred to as hot filling. However, hot filling has been shown to affect the clarity of the brine, making the product cloudy and unappealing to consumers. Because of the potential quality defects caused by higher temperatures associated with hot fill pickling, cold fill pickling, which uses room temperature brine, is preferred by some pickled sausage manufacturers. Because little information exists on the safety of cold fill, pickled sausages, a challenge study was designed using a brine solution (5% acetic acid and 5% salt at 25°C) to pickle precooked, RTE sausages inoculated with a pathogen cocktail consisting of Salmonella Typhimurium, Salmonella Senftenberg, Salmonella Montevideo, Listeria monocytogenes , and Staphylococcus aureus . All pathogens were reduced ~6.80 log CFU/g in 72 h when enumerated on nonselective media. On selective media, Salmonella and L. monocytogenes decreased 6.33 and 6.35 log CFU/g in 12 h, respectively whereas S. aureus was reduced 6.80 log CFU/g in 24 h. Sausages experienced significant (P ≤ 0.05) decreases in pH over the 28 days of storage, whereas no significant differences were observed in water activity (P =0.1291) or salt concentration of the sausages (P =0.1445) or brine (P =0.3180). The results of this experiment demonstrate that cold fill pickling can effectively reduce and inhibit bacterial pathogens.

  4. Control of Some Human Pathogenic Bacteria by Seed Extracts of Cumin (Cuminum cyminum L.)

    OpenAIRE

    2010-01-01

    Antibacterial activity of seed extracts of cumin (Cuminum cyminum L.) was investigated against 10 gram positive and gram negative bacteria. Disc diffusion method was used to test antibacterial activity. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined by using standard procedures. The highest (effective) inhibition zone of 16.67±0.47 mm was found at 250 mg/ml for Escherichia coli. On the other hand, the inhibition zones 15.00±0.82 mm f...

  5. Application of a pathogen microarray for the analysis of viruses and bacteria in clinical diagnostic samples from pigs.

    Science.gov (United States)

    Jaing, Crystal J; Thissen, James B; Gardner, Shea N; McLoughlin, Kevin S; Hullinger, Pam J; Monday, Nicholas A; Niederwerder, Megan C; Rowland, Raymond R R

    2015-05-01

    Many of the disease syndromes challenging the commercial swine industry involve the analysis of complex problems caused by polymicrobial, emerging or reemerging, and transboundary pathogens. This study investigated the utility of the Lawrence Livermore Microbial Detection Array (Lawrence Livermore National Laboratory, Livermore, California), designed to detect 8,101 species of microbes, in the evaluation of known and unknown microbes in serum, oral fluid, and tonsil from pigs experimentally coinfected with Porcine reproductive and respiratory syndrome virus (PRRSV) and Porcine circovirus-2 (PCV-2). The array easily identified PRRSV and PCV-2, but at decreased sensitivities compared to standard polymerase chain reaction detection methods. The oral fluid sample was the most informative, possessing additional signatures for several swine-associated bacteria, including Streptococcus sp., Clostridium sp., and Staphylococcus sp.

  6. Isolation of lactic acid bacteria with inhibitory activity against pathogens and spoilage organisms associated with fresh meat.

    Science.gov (United States)

    Jones, Rhys J; Hussein, Hassan M; Zagorec, Monique; Brightwell, Gale; Tagg, John R

    2008-04-01

    The use of lactic acid bacteria (LAB) as protective cultures in vacuum-packed chill-stored meat has potential application for assuring and improving food quality, safety and market access. In a study to identify candidate strains suitable for evaluation in a meat model, agar-based methods were employed to screen 181 chilled meat and meat process-related LAB for strains inhibitory to pathogens and spoilage organisms of importance to the meat industry. Six meat-derived strains, including Lactobacillus sakei and Lactococcus lactis, were found to be inhibitory to one or more of the target strains Listeria monocytogenes, Brochothrix thermosphacta, Campylobacter jejuni and Clostridium estertheticum. The inhibitory agents appeared to be either cell-associated or molecules released extracellularly with bacteriocin-like properties. Variations detected in the antimicrobial activity of LAB associated with changes to test parameters such as substrate composition underlined the importance of further in situ evaluation of the inhibitory strains in stored meat trials.

  7. Divergent pro-inflammatory profile of human dendritic cells in response to commensal and pathogenic bacteria associated with the airway microbiota

    DEFF Research Database (Denmark)

    Larsen, Jeppe Madura; Steen-Jensen, Daniel Bisgaard; Laursen, Janne Marie

    2012-01-01

    Recent studies using culture-independent methods have characterized the human airway microbiota and report microbial communities distinct from other body sites. Changes in these airway bacterial communities appear to be associated with inflammatory lung disease, yet the pro-inflammatory properties...... differences in DC stimulating properties of bacteria associated with the airway microbiota....... of individual bacterial species are unknown. In this study, we compared the immune stimulatory capacity on human monocyte-derived dendritic cells (DCs) of selected airway commensal and pathogenic bacteria predominantly associated with lungs of asthma or COPD patients (pathogenic Haemophillus spp. and Moraxella...

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

    Energy Technology Data Exchange (ETDEWEB)

    Fallah, Aziz A., E-mail: a_a_falah@yahoo.co [Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Research Institute of Zoonotic Diseases, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Siavash Saei-Dehkordi, S. [Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Research Institute of Zoonotic Diseases, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Rahnama, Mohammad [Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, University of Zabol, Zabol 98615 (Iran, Islamic Republic of)

    2010-10-15

    Ready-to-cook Iranian barbecued chicken consists of cubed chicken breast, lemon juice, salt, red pepper, onion, saffron and vegetable oil with an overall pH value of about 5.5. This product is sometimes consumed under-cooked, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. In this study, the effect of gamma irradiation (0, 1.5, 3 and 4.5 kGy) on the microbial quality of ready-to-cook (RTC) barbecued chicken samples stored at 4 {sup o}C for 15 days was investigated. Moreover, the effectiveness of irradiation for inactivating Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella typhimurium inoculated into the samples was also studied. Irradiation of the samples resulted in dose dependent reduction in counts of aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and lactic acid bacteria. Among the microbial flora, yeasts and molds and Enterobacteriaceae were more sensitive to irradiation and got completely eliminated at dose of 3 kGy. D{sub 10} values of L. monocytogenes, E. coli O157:H7 and S. typhimurium inoculated into the samples were 0.680, 0.397 and 0.601 kGy, respectively. An irradiation dose of 3 kGy reduced the counts of E. coli O157:H7 to an undetectable level in RTC barbecued chicken but was ineffective on elimination of L. monocytogenes and S. typhimurium. However, none of the food-borne pathogens were detected in the samples irradiated at 4.5 kGy. This study showed that irradiation had no undesirable effects on the initial sensory attributes of barbecued chicken. At the end of the storage period, irradiated samples were more acceptable compared to non-irradiated ones.

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

    Science.gov (United States)

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

    2010-10-01

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

  10. Gut Microbiota-Induced Immunoglobulin G Controls Systemic Infection by Symbiotic Bacteria and Pathogens.

    Science.gov (United States)

    Zeng, Melody Y; Cisalpino, Daniel; Varadarajan, Saranyaraajan; Hellman, Judith; Warren, H Shaw; Cascalho, Marilia; Inohara, Naohiro; Núñez, Gabriel

    2016-03-15

    The gut microbiota is compartmentalized in the intestinal lumen and induces local immune responses, but it remains unknown whether the gut microbiota can induce systemic response and contribute to systemic immunity. We report that selective gut symbiotic gram-negative bacteria were able to disseminate systemically to induce immunoglobulin G (IgG) response, which primarily targeted gram-negative bacterial antigens and conferred protection against systemic infections by E. coli and Salmonella by directly coating bacteria to promote killing by phagocytes. T cells and Toll-like receptor 4 on B cells were important in the generation of microbiota-specific IgG. We identified murein lipoprotein (MLP), a highly conserved gram-negative outer membrane protein, as a major antigen that induced systemic IgG homeostatically in both mice and humans. Administration of anti-MLP IgG conferred crucial protection against systemic Salmonella infection. Thus, our findings reveal an important function for the gut microbiota in combating systemic infection through the induction of protective IgG. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Antibiotic resistance and assessment of food-borne pathogenic bacteria in frozen foods.

    Science.gov (United States)

    Baek, Eunhye; Lee, Dokyung; Jang, Seok; An, Hyangmi; Kim, Mijin; Kim, Kyungjae; Lee, Kangoh; Ha, Namjoo

    2009-12-01

    One hundred ninety-three frozen food samples collected in Korea various public bazaars from October 2006 to September 2007. Staphylococci were detected in 21.8% of frozen food samples. Staphylococcus aureus was isolated from 17 (8.8%) samples. Other staphylococci isolates were identified as S. warneri (7.8%), S. epidermidis (2.1%), S. xylosus (1.6%), S. eguorum (1%), and S. vitulinus (0.5%). Additionally, the antimicrobial susceptibility of 42 staphylococcal isolates to ten different antimicrobial agents was determined. The staphylococcal isolates demonstrated antimicrobial resistance to mupirocin (31%) oxacillin (14.3%), gentamicin (9.5%), teicoplanin (7.1%) and ciprofloxacin (7.1%). Most of the staphylococcal isolates showed high-level resistance to mupirocin (MIC(90), >128 microg/mL). Fortunately, most of the isolates were susceptible to vancomycin. The total bacteria and Escherichia coli count were tested to investigate the microbiological quality of frozen foods. From 193 frozen food samples, 43 (22.3%), 34 (17.6%) and 19 (9.8%) samples were shown to be of unacceptable quality due to total bacteria, coliform and E. coli counts, respectively.

  12. Social and Economic Aspects of the Transmission of Pathogenic Bacteria between Wildlife and Food Animals: A Thematic Analysis of Published Research Knowledge.

    Science.gov (United States)

    Fournier, A; Young, I; Rajić, A; Greig, J; LeJeune, J

    2015-09-01

    Wildlife is a known reservoir of pathogenic bacteria, including Mycobacterium bovis and Brucella spp. Transmission of these pathogens between wildlife and food animals can lead to damaging impacts on the agri-food industry and public health. Several international case studies have highlighted the complex and cross-sectoral challenges involved in preventing and managing these potential transmission risks. The objective of our study was to develop a better understanding of the socio-economic aspects of the transmission of pathogenic bacteria between wildlife and food animals to support more effective and sustainable risk mitigation strategies. We conducted qualitative thematic analysis on a purposive sample of 30/141 articles identified in a complementary scoping review of the literature in this area and identified two key themes. The first related to the framing of this issue as a 'wicked problem' that depends on a complex interaction of social factors and risk perceptions, governance and public policy, and economic implications. The second theme consisted of promising approaches and strategies to prevent and mitigate the potential risks from transmission of pathogenic bacteria between wildlife and food animals. These included participatory, collaborative and multidisciplinary decision-making approaches and the proactive incorporation of credible scientific evidence and local contextual factors into solutions. The integration of these approaches to address 'wicked problems' in this field may assist stakeholders and decision-makers in improving the acceptability and sustainability of future strategies to reduce the transmission of pathogenic bacteria between wildlife and food animals.

  13. Washing-resistant surfactant coated surface is able to inhibit pathogenic bacteria adhesion

    Science.gov (United States)

    Treter, Janine; Bonatto, Fernando; Krug, Cristiano; Soares, Gabriel Vieira; Baumvol, Israel Jacob Rabin; Macedo, Alexandre José

    2014-06-01

    Surface-active substances, which are able to organize themselves spontaneously on surfaces, triggering changes in the nature of the solid-liquid interface, are likely to influence microorganism adhesion and biofilm formation. Therefore, this study aimed to evaluate chemical non-ionic surfactants activity against pathogenic microbial biofilms and to cover biomaterial surfaces in order to obtain an anti-infective surface. After testing 11 different surfactants, Pluronic F127 was selected for further studies due to its non-biocidal properties and capability to inhibit up to 90% of biofilm formation of Gram-positive pathogen and its clinical isolates. The coating technique using direct impregnation on the surface showed important antibiofilm formation characteristics, even after extensive washes. Surface roughness and bacterial surface polarity does not influence the adhesion of Staphylococcus epidermidis, however, the material coated surface became extremely hydrophilic. The phenotype of S. epidermidis does not seem to have been affected by the contact with surfactant, reinforcing the evidence that a physical phenomenon is responsible for the activity. This paper presents a simple method of surface coating employing a synthetic surfactant to prevent S. epidermidis biofilm formation.

  14. In vitro antibacterial potential of someVitex species against human pathogenic bacteria

    Institute of Scientific and Technical Information of China (English)

    Krishnan Kannathasan; Annadurai Senthilkumar; Venugopalan Venkatesalu

    2011-01-01

    Objective:To study the antibacterial activity of the leaf methanol extracts of five different species ofVitex namely,Vitex altissima (V. altissima),Vitex diversifolia (V. diversifolia),Vitex negundo(V. negundo),Vitex peduncularis (V. peduncularis) andVitex trifolia (V. trifolia). Methods: Antibacterial assay was carried out by using disc diffusion method, determination of minimum inhibitory concentrations (MIC)and minimum bactericidal concentrations(MBC)against five strains of Gram-positive and seven strains of Gram-negative human pathogenic bacterial strains.Results: The results of antibacterial activity ofVitex species showed that the extracts possessed a broad spectrum of antibacterial activity. TheV. peduncularis possessed the highest activity against all the microorganisms screened. It produced a zone of inhibition ranged between (11.000± 0.577) and(22.670 ± 0.667) mm and theMIC values were from 62.5 to1 000.0 μg/mL and theMBCvalues were from 125.0to2 000.0μg/mL.Conclusions:Based on the present study, V. peduncularis is recommended for the isolation of antibacterial molecule responsible for the activity against the tested human pathogenic bacterial strains.

  15. Antimicrobial activity of lactic acid bacteria in dairy products and gut: effect on pathogens.

    Science.gov (United States)

    Arqués, Juan L; Rodríguez, Eva; Langa, Susana; Landete, José María; Medina, Margarita

    2015-01-01

    The food industry seeks alternatives to satisfy consumer demands of safe foods with a long shelf-life able to maintain the nutritional and organoleptic quality. The application of antimicrobial compounds-producing protective cultures may provide an additional parameter of processing in order to improve the safety and ensure food quality, keeping or enhancing its sensorial characteristics. In addition, strong evidences suggest that certain probiotic strains can confer resistance against infection with enteric pathogens. Several mechanisms have been proposed to support this phenomenon, including antimicrobial compounds secreted by the probiotics, competitive exclusion, or stimulation of the immune system. Recent research has increasingly demonstrated the role of antimicrobial compounds as protective mechanism against intestinal pathogens and therefore certain strains could have an effect on both the food and the gut. In this aspect, the effects of the combination of different strains keep unknown. The development of multistrain probiotic dairy products with good technological properties and with improved characteristics to those shown by the individual strains, able to act not only as protective cultures in foods, but also as probiotics able to exert a protective action against infections, has gained increased interest.

  16. Inhibitory effect of Allium sativum and Zingiber officinale extracts on clinically important drug resistant pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Gull Iram

    2012-04-01

    Full Text Available Abstract Background Herbs and spices are very important and useful as therapeutic agent against many pathological infections. Increasing multidrug resistance of pathogens forces to find alternative compounds for treatment of infectious diseases. Methods In the present study the antimicrobial potency of garlic and ginger has been investigated against eight local clinical bacterial isolates. Three types of extracts of each garlic and ginger including aqueous extract, methanol extract and ethanol extract had been assayed separately against drug resistant Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, Shigella sonnei, Staphylococcusepidermidis and Salmonella typhi. The antibacterial activity was determined by disc diffusion method. Results All tested bacterial strains were most susceptible to the garlic aqueous extract and showed poor susceptibility to the ginger aqueous extract. The (minimum inhibitory concentration MIC of different bacterial species varied from 0.05 mg/ml to 1.0 mg/ml. Conclusion In the light of several socioeconomic factors of Pakistan mainly poverty and poor hygienic condition, present study encourages the use of spices as alternative or supplementary medicine to reduce the burden of high cost, side effects and progressively increasing drug resistance of pathogens.

  17. Antimicrobial Activity of Lactic Acid Bacteria in Dairy Products and Gut: Effect on Pathogens

    Directory of Open Access Journals (Sweden)

    Juan L. Arqués

    2015-01-01

    Full Text Available The food industry seeks alternatives to satisfy consumer demands of safe foods with a long shelf-life able to maintain the nutritional and organoleptic quality. The application of antimicrobial compounds-producing protective cultures may provide an additional parameter of processing in order to improve the safety and ensure food quality, keeping or enhancing its sensorial characteristics. In addition, strong evidences suggest that certain probiotic strains can confer resistance against infection with enteric pathogens. Several mechanisms have been proposed to support this phenomenon, including antimicrobial compounds secreted by the probiotics, competitive exclusion, or stimulation of the immune system. Recent research has increasingly demonstrated the role of antimicrobial compounds as protective mechanism against intestinal pathogens and therefore certain strains could have an effect on both the food and the gut. In this aspect, the effects of the combination of different strains keep unknown. The development of multistrain probiotic dairy products with good technological properties and with improved characteristics to those shown by the individual strains, able to act not only as protective cultures in foods, but also as probiotics able to exert a protective action against infections, has gained increased interest.

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

    Science.gov (United States)

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

    2007-09-01

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

  19. Divergent pro-inflammatory profile of human dendritic cells in response to commensal and pathogenic bacteria associated with the airway microbiota.

    Science.gov (United States)

    Larsen, Jeppe Madura; Steen-Jensen, Daniel Bisgaard; Laursen, Janne Marie; Søndergaard, Jonas Nørskov; Musavian, Hanieh Sadat; Butt, Tariq Mahmood; Brix, Susanne

    2012-01-01

    Recent studies using culture-independent methods have characterized the human airway microbiota and report microbial communities distinct from other body sites. Changes in these airway bacterial communities appear to be associated with inflammatory lung disease, yet the pro-inflammatory properties of individual bacterial species are unknown. In this study, we compared the immune stimulatory capacity on human monocyte-derived dendritic cells (DCs) of selected airway commensal and pathogenic bacteria predominantly associated with lungs of asthma or COPD patients (pathogenic Haemophillus spp. and Moraxella spp.), healthy lungs (commensal Prevotella spp.) or both (commensal Veillonella spp. and Actinomyces spp.). All bacteria were found to induce activation of DCs as demonstrated by similar induction of CD83, CD40 and CD86 surface expression. However, asthma and COPD-associated pathogenic bacteria provoked a 3-5 fold higher production of IL-23, IL-12p70 and IL-10 cytokines compared to the commensal bacteria. Based on the differential cytokine production profiles, the studied airway bacteria could be segregated into three groups (Haemophilus spp. and Moraxella spp. vs. Prevotella spp. and Veillonella spp. vs. Actinomyces spp.) reflecting their pro-inflammatory effects on DCs. Co-culture experiments found that Prevotella spp. were able to reduce Haemophillus influenzae-induced IL-12p70 in DCs, whereas no effect was observed on IL-23 and IL-10 production. This study demonstrates intrinsic differences in DC stimulating properties of bacteria associated with the airway microbiota.

  20. Divergent pro-inflammatory profile of human dendritic cells in response to commensal and pathogenic bacteria associated with the airway microbiota.

    Directory of Open Access Journals (Sweden)

    Jeppe Madura Larsen

    Full Text Available Recent studies using culture-independent methods have characterized the human airway microbiota and report microbial communities distinct from other body sites. Changes in these airway bacterial communities appear to be associated with inflammatory lung disease, yet the pro-inflammatory properties of individual bacterial species are unknown. In this study, we compared the immune stimulatory capacity on human monocyte-derived dendritic cells (DCs of selected airway commensal and pathogenic bacteria predominantly associated with lungs of asthma or COPD patients (pathogenic Haemophillus spp. and Moraxella spp., healthy lungs (commensal Prevotella spp. or both (commensal Veillonella spp. and Actinomyces spp.. All bacteria were found to induce activation of DCs as demonstrated by similar induction of CD83, CD40 and CD86 surface expression. However, asthma and COPD-associated pathogenic bacteria provoked a 3-5 fold higher production of IL-23, IL-12p70 and IL-10 cytokines compared to the commensal bacteria. Based on the differential cytokine production profiles, the studied airway bacteria could be segregated into three groups (Haemophilus spp. and Moraxella spp. vs. Prevotella spp. and Veillonella spp. vs. Actinomyces spp. reflecting their pro-inflammatory effects on DCs. Co-culture experiments found that Prevotella spp. were able to reduce Haemophillus influenzae-induced IL-12p70 in DCs, whereas no effect was observed on IL-23 and IL-10 production. This study demonstrates intrinsic differences in DC stimulating properties of bacteria associated with the airway microbiota.

  1. Effects of modified atmosphere and vacuum packaging on the growth of spoilage and inoculated pathogenic bacteria on fresh poultry.

    Science.gov (United States)

    Ozbaş, Z Y; Vural, H; Aytaç, S A

    1996-10-01

    Fresh chicken breast meats inoculated with Yersinia enterocolitica and Aeromonas hydrophila were packaged in glass jars either containing different compositions of modified atmospheres (MA) (100% CO2; 80% CO2/20% N2), or in vacuo or containing air, and were stored at 3 +/- 1 degrees C and 8 +/- 1 degrees C. The changes in gas composition as well as Y. enterocolitica, A. hydrophila, total aerobic bacterial, total psychotropic, Lactobacilli and Enterobacteriaceae counts were determined after 0, 1, 3, 7, 9, 11 and 14 days of storage. The results show that while the growth of Y. enterocolitica and A. hydrophila were retarded following MA storage, the pathogens were capable of growth in MA and vacuum storage at both temperatures, for the inoculation levels studied. For total aerobic bacterial counts, there were no differences between the values for chicken breast meats kept in different atmospheres. Being packaged in CO2 had the greatest inhibitory effect on the growth of psychotropic aerobic bacteria during the first 3 days. Lactic acid bacteria levels of samples stored in MA conditions and in vacuo increased rapidly when compared to those levels of samples stored in air. It was also found that the effect of MA storage increased at 3 +/- 1 degrees C.

  2. Isolation and Identification of Pathogenic Bacteria from Brackish Waters of Chilika Lagoon, Odisha, India for Pharmaceutical Use

    Directory of Open Access Journals (Sweden)

    Subhashree Parida

    2012-09-01

    Full Text Available Aims: The present investigation was undertaken in order to isolate bacteria from eighteen different water samples collected from three different sectors of ‘Chilika’ lagoon of India and to study the resistance against ten different antibiotics viz., norfloxacin, tetracycline, ciprofloxacin, neomycin, nalidixic acid, ofloxacin, chloramphenicol, nitrofurantoin, streptomycin and amoxicillin as well as their serological implications.Methodology and Results: Four different pathogenic bacteria species viz., Shigella dysenteriae, Streptococcus lactis, Bacillus cereus and Klebsiella pneumoniae were isolated which showed a wide range of sensitivity to norfloxacin,tetracycline, ciprofloxacin, ofloxacin and nitrofurantoin. S. dysenteriae was sensitive to streptomycin where as other isolates were found to be resistant. Agarose gel electrophoresis failed to reveal plasmid DNA band indicating that theobserved resistance was perhaps encoded by nucleotide sequences harboured on the chromosomal DNA. Bacterial isolates were used as antigen for the production of polyclonal antibodies in rabbits.Conclusion, significance and impact of study:All the isolates exhibited strong antigenic character with specific serological relationship which can be implicated towards development of novel and pharmaceutically effective antibacterial products.

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

    Science.gov (United States)

    Nei, Daisuke; Enomoto, Katsuyoshi; Nakamura, Nobutaka

    2015-08-01

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

  4. Screening of extracts of algae from Baja California sur, Mexico as reversers of the antibiotic resistance of some pathogenic bacteria.

    Science.gov (United States)

    Muñoz-Ochoa, M; Murillo-Alvarez, J I; Zermeño-Cervantes, L A; Martínez-Diaz, S; Rodríguez-Riosmena, R

    2010-09-01

    Sixty ethanol extracts of marine flora of Baja California Sur (Mexico) were screened to evaluate the reversing effect of the bacterial resistance to antibiotics in combination with a sublethal concentration of ampicillin or erythromycin. The activity was assayed by using a modification of the classical agar-diffusion method against 3 resistant, pathogenic bacteria; Escherichia coil (ATCC BAA196), Staphylococcus aureus (ATCC BAA42), and Streptococcus pyogenes (ATCC BAA946). From the 60 ethanolic extracts, 12 (20%) of them in combination with ampicillin were able to reverse the resistance of Staphylococcus aureus and 8 (13%) with erythromycin yielded the same reversal with Streptococcus pyogenes. An extract from Sargassum horridum was the only one that reversed the resistance to antibiotics against both Staphylococcus aureus and Streptococcus pyogenes. Our findings suggest that some algae may be source of compounds with the potential to reverse the antibiotic resistance of some bacteria. In addition, of the assayed extracts, 35 (57%) showed inhibitory activity against Staphylococcus aureus, 48 (78%) were active against Streptococcus pyogenes, but none was active against Escherichia coil. The most active extracts were from Laurencia spp., Gelidium robustum, Chnoospora implexa, Padina mexicana, Gracilaria subsecundata, and Dictyopteris undulata.

  5. Antibacterial Activity and Action Mechanism of the Essential Oil from Enteromorpha linza L. against Foodborne Pathogenic Bacteria.

    Science.gov (United States)

    Patra, Jayanta Kumar; Baek, Kwang-Hyun

    2016-03-21

    Foodborne illness and disease caused by foodborne pathogenic bacteria is continuing to increase day by day and it has become an important topic of concern among various food industries. Many types of synthetic antibacterial agents have been used in food processing and food preservation; however, they are not safe and have resulted in various health-related issues. Therefore, in the present study, essential oil from an edible seaweed, Enteromorpha linza (AEO), was evaluated for its antibacterial activity against foodborne pathogens, along with the mechanism of its antibacterial action. AEO at 25 mg/disc was highly active against Bacillus cereus (12.3-12.7 mm inhibition zone) and Staphylococcus aureus (12.7-13.3 mm inhibition zone). The minimum inhibitory concentration and minimum bactericidal concentration values of AEO ranged from 12.5-25 mg/mL. Further investigation of the mechanism of action of AEO revealed its strong impairing effect on the viability of bacterial cells and membrane permeability, as indicated by a significant increase in leakage of 260 nm absorbing materials and K⁺ ions from the cell membrane and loss of high salt tolerance. Taken together, these data suggest that AEO has the potential for use as an effective antibacterial agent that functions by impairing cell membrane permeability via morphological alternations, resulting in cellular lysis and cell death.

  6. Strategies for Pathogen Biocontrol Using Lactic Acid Bacteria and Their Metabolites: A Focus on Meat Ecosystems and Industrial Environments

    Directory of Open Access Journals (Sweden)

    Patricia Castellano

    2017-07-01

    Full Text Available The globalization of trade and lifestyle ensure that the factors responsible for the emergence of diseases are more present than ever. Despite biotechnology advancements, meat-based foods are still under scrutiny because of the presence of pathogens, which causes a loss of consumer confidence and consequently a fall in demand. In this context, Lactic Acid Bacteria (LAB as GRAS organisms offer an alternative for developing pathogen-free foods, particularly avoiding Listeria monocytogenes, with minimal processing and fewer additives while maintaining the foods’ sensorial characteristics. The use of LAB strains, enabling us to produce antimicrobial peptides (bacteriocins in addition to lactic acid, with an impact on quality and safety during fermentation, processing, and/or storage of meat and ready-to-eat (RTE meat products, constitutes a promising tool. A number of bacteriocin-based strategies including the use of bioprotective cultures, purified and/or semi-purified bacteriocins as well as their inclusion in varied packaging materials under different storage conditions, have been investigated. The application of bacteriocins as part of hurdle technology using non-thermal technologies was explored for the preservation of RTE meat products. Likewise, considering that food contamination with L. monocytogenes is a consequence of the post-processing manipulation of RTE foods, the role of bacteriocinogenic LAB in the control of biofilms formed on industrial surfaces is also discussed.

  7. Associations among pathogenic bacteria, parasites, and environmental and land use factors in multiple mixed-use watersheds.

    Science.gov (United States)

    Wilkes, G; Edge, T A; Gannon, V P J; Jokinen, C; Lyautey, E; Neumann, N F; Ruecker, N; Scott, A; Sunohara, M; Topp, E; Lapen, D R

    2011-11-15

    Over a five year period (2004-08), 1171 surface water samples were collected from up to 24 sampling locations representing a wide range of stream orders, in a river basin in eastern Ontario, Canada. Water was analyzed for Cryptosporidium oocysts and Giardia cyst densities, the presence of Salmonella enterica subspecies enterica, Campylobacter spp., Listeria monocytogenes, and Escherichia coli O157:H7. The study objective was to explore associations among pathogen densities/occurrence and objectively defined land use, weather, hydrologic, and water quality variables using CART (Classification and Regression Tree) and binary logistical regression techniques. E. coli O157:H7 detections were infrequent, but detections were related to upstream livestock pasture density; 20% of the detections were located where cattle have access to the watercourses. The ratio of detections:non-detections for Campylobacter spp. was relatively higher (>1) when mean air temperatures were 6% below mean study period temperature values (relatively cooler periods). Cooler water temperatures, which can promote bacteria survival and represent times when land applications of manure typically occur (spring and fall), may have promoted increased frequency of Campylobacter spp. Fifty-nine percent of all Salmonella spp. detections occurred when river discharge on a branch of the river system of Shreve stream order = 9550 was >83 percentile. Hydrological events that promote off farm/off field/in stream transport must manifest themselves in order for detection of Salmonella spp. to occur in surface water in this region. Fifty seven percent of L. monocytogenes detections occurred in spring, relative to other seasons. It was speculated that a combination of winter livestock housing, silage feeding during winter, and spring application of manure that accrued during winter, contributed to elevated occurrences of this pathogen in spring. Cryptosporidium and Giardia oocyst and cyst densities were, overall

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

    Science.gov (United States)

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

    2013-01-01

    The survival of eight undesired (spoilage/pathogenic) food related bacteria (Citrobacter freundii PSS60, Enterobacter spp. PSS11, Escherichia coli PSS2, Klebsiella oxytoca PSS82, Serratia grimesii PSS72, Pseudomonas putida PSS21, Stenotrophomonas maltophilia PSS52 and Listeria monocytogenes ATCC 19114(T)) was investigated in mineral nutrient solution (MNS) during the crop cycle of radishes (Raphanus sativus L.) cultivated in hydroponics in a greenhouse. MNSs were microbiologically analyzed weekly by plate count. The evolution of the pure cultures was also evaluated in sterile MNS in test tubes. The inoculated trials contained an initial total mesophilic count (TMC) ranging between 6.69 and 7.78Log CFU/mL, while non-sterile and sterile control trials showed levels of 4.39 and 0.97Log CFU/mL, respectively. In general, all inoculated trials showed similar levels of TMC in MNS during the experimentation, even though the levels of the inoculated bacteria decreased. The presence of the inoculums was ascertained by randomly amplified polymorphic DNA (RAPD) analysis applied on the isolates collected at 7-day intervals. At harvest, MNSs were also analyzed by denaturing gradient gel electrophoresis (DGGE). The last analysis, except P. putida PSS21 in the corresponding trial, did not detect the other bacteria, but confirmed that pseudomonads were present in un-inoculated MNSs. Despite the high counts detected (6.44 and 7.24CFU/g), only C. freundii PSS60, Enterobacter spp. PSS11 and K. oxytoca PSS82 were detected in radishes in a living form, suggesting their internalization. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria

    DEFF Research Database (Denmark)

    Ebbensgaard, Anna Elisabeth; Mordhorst, Hanne; Overgaard, Michael Toft

    2015-01-01

    The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various...... AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram......-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli...

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

    Science.gov (United States)

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

    2016-04-01

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

  11. Inhibition by the essential oils of peppermint and spearmint of the growth of pathogenic bacteria.

    Science.gov (United States)

    Imai, H; Osawa, K; Yasuda, H; Hamashima, H; Arai, T; Sasatsu, M

    2001-01-01

    The effects of the, essential oils of peppermint (Mentha piperita L.), spearmint Mentha spicata L.) and Japanese mint (Mentha, arvensis L.), of four major constituents of the esssential oil of peppermint, and of three major constituents of the essential oil of spearmint, on the proliferation of Helicobacter pylori, Salmonella enteritidis, Escherichia coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin sensitive Staphylococccus aureus (MSSA) were examined. The essential oils and the various constituents inhibited the proliferation of each strain in liquid culture in a dose-dependent manner. In addition, they exhibited bactericidal activity in phosphate-buffered saline. The antibacterial activities varied among the bacterial species tested but were almost the same against antibiotic-resistant and antibiotic-sensitive strains of Helicobacter pylori and S. aureus. Thus, the essential oils and their constituents may be useful as potential antibacterial agents for inhibition of the growth of pathogens.

  12. Occurrence of Vibrio and other pathogenic bacteria in Mytilus galloprovincialis (mussels) harvested from Adriatic Sea, Italy.

    Science.gov (United States)

    Ripabelli, G; Sammarco, M L; Grasso, G M; Fanelli, I; Caprioli, A; Luzzi, I

    1999-08-01

    Sixty-two samples of Mytilus galloprovincialis (mussels) harvested from approved shellfish waters in the Adriatic Sea were examined for the presence of Vibrio, Salmonella, Campylobacter, and verocytotoxin producing Escherichia coli. Vibrio spp. were isolated from 48.4% of samples; the species most frequently found were V. alginolyticus (32.2%) and V. vulnificus (17.7%), followed by V. cincinnatiensis (3.2%), V. parahaemolyticus (1.6%), V. fluvialis (1.6%) and V. cholerae non-O1 (1.6%). V. parahaemolyticus resulted negative to Kanagawa-phenomenon and to PCR amplification of tdh gene. V. cholerae resulted negative to PCR amplification of sto gene. No Salmonella, Campylobacter, or E. coli verocytotoxin-producing strains were isolated. The results of this study suggest the potential risk of ingesting raw or undercooked mussels due to the frequent presence of potentially pathogenic Vibrio species.

  13. Antibacterial activity of commercially available plant-derived essential oils against oral pathogenic bacteria.

    Science.gov (United States)

    Bardají, D K R; Reis, E B; Medeiros, T C T; Lucarini, R; Crotti, A E M; Martins, C H G

    2016-01-01

    This work investigated the antibacterial activity of 15 commercially available plant-derived essential oils (EOs) against a panel of oral pathogens. The broth microdilution method afforded the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the assayed EOs. The EO obtained from Cinnamomum zeylanicum (Lauraceae) (CZ-EO) displayed moderate activity against Fusobacterium nucleatum (MIC and MBC = 125 μg/mL), Actinomyces naeslundii (MIC and MBC = 125 μg/mL), Prevotella nigrescens (MIC and MBC = 125 μg/mL) and Streptococcus mutans (MIC = 200 μg/mL; MBC = 400 μg/mL). (Z)-isosafrole (85.3%) was the main chemical component of this oil. We did not detect cinnamaldehyde, previously described as the major constituent of CZ-EO, in specimens collected in other countries.

  14. Effects of mutation and some environmental factors on the physiology and pathogenicity of selected bacteria

    Science.gov (United States)

    Decicco, B. T.

    1974-01-01

    Studies with mutants of Staphylococcus aureus lacking some virulence factors suggest that the presence of deoxyribonuclease correlates with mouse pathogenicity of S. aureus, while the ability to ferment mannitol or the possession of coagulases are not required for virulence. Autotrophy investigations on mycobacteria demonstrate a complete correlation between the ability to grow with hydrogen and the species of scotochromogenic mycobacterium tested. All tested strains of M. gordonae, a saprophyte, could grow autotrophically while none of the tested strains of M. scrofulaceum, a clinically important species, possessed this ability. A series of heat tolerant mutants of Pseudomonas fluorescences were obtained which can grow at temperatures up to 54 C, in contrast to a maximum growth temperature of 37 C for the wild type.

  15. Bacteria Murmur: Application of an Acoustic Biosensor for Plant Pathogen Detection.

    Directory of Open Access Journals (Sweden)

    George Papadakis

    Full Text Available A multi-targeting protocol for the detection of three of the most important bacterial phytopathogens, based on their scientific and economic importance, was developed using an acoustic biosensor (the Quartz Crystal Microbalance for DNA detection. Acoustic detection was based on a novel approach where DNA amplicons were monitored and discriminated based on their length rather than mass. Experiments were performed during real time monitoring of analyte binding and in a direct manner, i.e. without the use of labels for enhancing signal transduction. The proposed protocol improves time processing by circumventing gel electrophoresis and can be incorporated as a routine detection method in a diagnostic lab or an automated lab-on-a-chip system for plant pathogen diagnostics.

  16. Bacteria Murmur: Application of an Acoustic Biosensor for Plant Pathogen Detection.

    Science.gov (United States)

    Papadakis, George; Skandalis, Nicholas; Dimopoulou, Anastasia; Glynos, Paraskevas; Gizeli, Electra

    2015-01-01

    A multi-targeting protocol for the detection of three of the most important bacterial phytopathogens, based on their scientific and economic importance, was developed using an acoustic biosensor (the Quartz Crystal Microbalance) for DNA detection. Acoustic detection was based on a novel approach where DNA amplicons were monitored and discriminated based on their length rather than mass. Experiments were performed during real time monitoring of analyte binding and in a direct manner, i.e. without the use of labels for enhancing signal transduction. The proposed protocol improves time processing by circumventing gel electrophoresis and can be incorporated as a routine detection method in a diagnostic lab or an automated lab-on-a-chip system for plant pathogen diagnostics.

  17. Copper as an antibacterial agent for human pathogenic multidrug resistant Burkholderia cepacia complex bacteria.

    Science.gov (United States)

    Ibrahim, Muhammad; Wang, Fang; Lou, Miao-miao; Xie, Guan-lin; Li, Bin; Bo, Zhu; Zhang, Gou-qing; Liu, He; Wareth, Abdul

    2011-12-01

    The Burkholderia cepacia complex (Bcc) consists of 17 closely related multidrug resistant bacterial species that are difficult to eradicate. Copper has recently gained attention as an antimicrobial agent because of its inhibitory effects on bacteria, yeast, and viruses. The objective of this study was to evaluate the antibacterial activity of copper surfaces and copper powder against members of the B. cepacia complex. The antibacterial activity of different copper surfaces was evaluated by incubating them with Bcc strain suspensions (5×10(7)cfu/ml). The bacterial survival counts were calculated and the data for various copper surfaces were compared to the data for stainless steel and polyvinylchloride, which were used as control surfaces. The antibacterial activity of copper powder was determined with the diffusimetrical technique and the zone of inhibition was evaluated with paper disks. A single cell gel electrophoresis assay, staining assays, and inductively coupled plasma mass spectroscopy were performed to determine the mechanism responsible for the bactericidal activity. The results showed a significant decrease in the viable bacterial count after exposure to copper surfaces. Moreover, the copper powder produced a large zone of inhibition and there was a significantly higher influx of copper ions into the bacterial cells that were exposed to copper surfaces compared to the controls. The present study demonstrates that metallic copper has an antibacterial effect against Bcc bacteria and that copper adversely affects the bacterial cellular structure, thus resulting in cell death. These findings suggest that copper could be utilized in health care facilities to reduce the bioburden of Bcc species, which may protect susceptible members of the community from bacterial infection.

  18. Antibacterial activity of the terrestrial fernLygodium flexuosum (L.) Sw. against multidrug resistant enteric- and uro-pathogenic bacteria

    Institute of Scientific and Technical Information of China (English)

    Nabakishore Nayak; Sibanarayan Rath; Monali P Mishra; Goutam Ghosh; Rabindra N Padhy

    2013-01-01

    Objective:To investigate antibacterial properties of the terrestrial fernLygodium flexuosum (L. flexuosum) obtained fromKalahandi district,Odisha against enteric- and uro-pathogenic bacteria isolated from clinical samples.Method:Frond-extracts ofL. flexuosum were obtained by the cold percolation method using four solvents, petroleum ether, chloroform, methanol and water.Antibacterial potencies of concentrated cold frond-extracts were tested by the agar-well diffusion method against7 multidrug resistant(MDR) bacteria of which,2 wereGram-positives, methicillin resistantStaphylococcus aureus(MRSA) and vancomycin resistantEnterococcus faecalis(VRE), and5Gram-negatives,Enterobacter aerogenes,Escherichia coli,Klebsiella pneumoniae, Pseudomonas aeruginosa andProteus mirabilis.Result:The cold-water frond-extract had the best antimicrobial activity against7MDR bacterial isolates, compared to extracts with other solvents.Values of zones of inhibition againstMRSA andP. mirabilis were the highest, 29 mm.Zones of inhibition againstVRE andP. aeruginosa were25 mm, while those were23 mm againstE. aerogenes andE. coli.The least size of zone of inhibition19 mm was recorded against K. pneumoniae.Minimum inhibitory concentration(MIC) and minimum bactericidal concentration (MBC) values of active frond-extracts with water, chloroform, methanol, and petroleum ether were recorded.For the water extract, theMIC value1.562 mg/mL againstMRSA andP. mirabilis, but the value3.25 mg/mL againstVRE,E. aerogenes andP. aeruginosa, while the value of12.5 mg/mL againstK. pneumoniae were recorded.MBC values were the least with chloroform-extracts, with the range12.5 for6 bacteria, excludingP. aeruginosa for which, the value25 mg/mL was recorded asMBC.Conclusions:Phytochemical analysis of the water-extract ofL. flexuosum confirmed the presence of glycosides and carbohydrates, but alkaloids, terpenoids, steroids, saponins, tannins, and flavonoids were absent.L. flexuosum, being a fern, is a suitable non

  19. Do symbiotic bacteria subvert host immunity?

    Science.gov (United States)

    Hooper, Lora V

    2009-05-01

    The mammalian intestine is home to dense and complex indigenous bacterial communities. Most of these bacteria establish beneficial symbiotic relationships with their hosts, making important contributions to host metabolism and digestive efficiency. The vast numbers of intestinal bacteria and their proximity to host tissues raise the question of how symbiotic host-bacterial relationships are established without eliciting potentially harmful immune responses. In light of the varied ways in which pathogenic bacteria manipulate host immunity, this Opinion article explores the role of immune suppression, subversion and evasion in the establishment of symbiotic host-bacterial associations.

  20. Structural characterization and comparison of three acyl-carrier-protein synthases from pathogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Halavaty, Andrei S. [Center for Structural Genomics of Infectious Diseases, (United States); Northwestern University, Chicago, IL 60611 (United States); Kim, Youngchang [Center for Structural Genomics of Infectious Diseases, (United States); Argonne National Laboratory, Argonne, IL 60439 (United States); University of Chicago, Chicago, IL 60637 (United States); Minasov, George; Shuvalova, Ludmilla; Dubrovska, Ievgeniia; Winsor, James [Center for Structural Genomics of Infectious Diseases, (United States); Northwestern University, Chicago, IL 60611 (United States); Zhou, Min [Center for Structural Genomics of Infectious Diseases, (United States); Argonne National Laboratory, Argonne, IL 60439 (United States); University of Chicago, Chicago, IL 60637 (United States); Onopriyenko, Olena; Skarina, Tatiana [Center for Structural Genomics of Infectious Diseases, (United States); University of Toronto, Toronto, Ontario M5G 1L6 (Canada); Papazisi, Leka; Kwon, Keehwan; Peterson, Scott N. [Center for Structural Genomics of Infectious Diseases, (United States); J. Craig Venter Institute, Rockville, MD 20850 (United States); Joachimiak, Andrzej [Center for Structural Genomics of Infectious Diseases, (United States); Argonne National Laboratory, Argonne, IL 60439 (United States); University of Chicago, Chicago, IL 60637 (United States); Savchenko, Alexei [Center for Structural Genomics of Infectious Diseases, (United States); University of Toronto, Toronto, Ontario M5G 1L6 (Canada); Anderson, Wayne F., E-mail: wf-anderson@northwestern.edu [Center for Structural Genomics of Infectious Diseases, (United States); Northwestern University, Chicago, IL 60611 (United States)

    2012-10-01

    The structural characterization of acyl-carrier-protein synthase (AcpS) from three different pathogenic microorganisms is reported. One interesting finding of the present work is a crystal artifact related to the activity of the enzyme, which fortuitously represents an opportunity for a strategy to design a potential inhibitor of a pathogenic AcpS. Some bacterial type II fatty-acid synthesis (FAS II) enzymes have been shown to be important candidates for drug discovery. The scientific and medical quest for new FAS II protein targets continues to stimulate research in this field. One of the possible additional candidates is the acyl-carrier-protein synthase (AcpS) enzyme. Its holo form post-translationally modifies the apo form of an acyl carrier protein (ACP), which assures the constant delivery of thioester intermediates to the discrete enzymes of FAS II. At the Center for Structural Genomics of Infectious Diseases (CSGID), AcpSs from Staphylococcus aureus (AcpS{sub SA}), Vibrio cholerae (AcpS{sub VC}) and Bacillus anthracis (AcpS{sub BA}) have been structurally characterized in their apo, holo and product-bound forms, respectively. The structure of AcpS{sub BA} is emphasized because of the two 3′, 5′-adenosine diphosphate (3′, 5′-ADP) product molecules that are found in each of the three coenzyme A (CoA) binding sites of the trimeric protein. One 3′, 5′-ADP is bound as the 3′, 5′-ADP part of CoA in the known structures of the CoA–AcpS and 3′, 5′-ADP–AcpS binary complexes. The position of the second 3′, 5′-ADP has never been described before. It is in close proximity to the first 3′, 5′-ADP and the ACP-binding site. The coordination of two ADPs in AcpS{sub BA} may possibly be exploited for the design of AcpS inhibitors that can block binding of both CoA and ACP.

  1. EFSA Panel on Biological Hazards (BIOHAZ); Scientific Opinion on the risk posed by Shiga toxinproducing Escherichia coli (STEC) and other pathogenic bacteria in seeds and sprouted seeds

    DEFF Research Database (Denmark)

    Hald, Tine

    Sprouted seeds are young seedlings obtained from the germination of seeds. They are ready-to-eat foods which have caused large outbreaks. The bacterial pathogens most frequently associated with illness due to contaminated sprouted seeds are Salmonella and to a lesser extent STEC. Bacillus cereus...... be contaminated during production, harvest, storage and transport, and there may be difficulties in traceability of seeds from production to sprouting. Bacterial pathogens on seeds may survive for long periods during seed storage. There is so far no guarantee of a bactericidal step which is able to control...... contamination of seeds with bacterial foodborne pathogens acquired prior to germination. Due to the high humidity and the favourable temperature during sprouting, bacterial pathogens present on dry seeds can multiply on the sprouts. Contamination with pathogenic bacteria must be minimized by identification...

  2. Antibacterial behaviour of Vitex negundo extract assisted ZnO nanoparticles against pathogenic bacteria.

    Science.gov (United States)

    Ambika, Subramanian; Sundrarajan, Mahalingam

    2015-05-01

    The biological routes are advantageous over the chemical and physical ones as unlike. These, the biological synthesis protocol occurs at ambient conditions, are cheap, non-toxic and eco-friendly. This research describes the synthesis of zinc oxide nanoparticles (ZnO NPs) using Vitex negundo plant extract with zinc nitrate hexahydrate as precursor. Biomolecules present in plant extract can be used to hydrolyze metal ions into metal oxide NPs in a single-step green synthesis. The hydrolyzing agents involved the various water soluble plant metabolites such as flavonoid, alkaloids, flavone, phenolic compounds, terpenoids and co-enzymes. Presence of isoorientin (flavone) in V. negundo plant extract is mainly responsible for the formation of ZnO NPs. The prepared ZnO NPs were calcinated at 450°C and were confirmed by XRD, FT-IR, UV-visible, SEM with EDX and DLS analysis. The biological application of antibacterial activity was done by gram positive and gram negative bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Antimicrobial effect of emulsion-encapsulated isoeugenol against biofilms of food pathogens and spoilage bacteria.

    Science.gov (United States)

    Krogsgård Nielsen, Christina; Kjems, Jørgen; Mygind, Tina; Snabe, Torben; Schwarz, Karin; Serfert, Yvonne; Meyer, Rikke Louise

    2017-02-02

    Food-related biofilms can cause food-borne illnesses and spoilage, both of which are problems on a global level. Essential oils are compounds derived from plant material that have a potential to be used in natural food preservation in the future since they are natural antimicrobials. Bacterial biofilms are particularly resilient towards biocides, and preservatives that effectively eradicate biofilms are therefore needed. In this study, we test the antibacterial properties of emulsion-encapsulated and unencapsulated isoeugenol against biofilms of Lis. monocytogenes, S. aureus, P. fluorescens and Leu. mesenteroides in tryptic soy broth and carrot juice. We show that emulsion encapsulation enhances the antimicrobial properties of isoeugenol against biofilms in media but not in carrot juice. Some of the isoeugenol emulsions were coated with chitosan, and treatment of biofilms with these emulsions disrupted the biofilm structure. Furthermore, we show that addition of the surfactant Tween 80, which is commonly used to disperse oils in food, hampers the antibacterial properties of isoeugenol. This finding highlights that common food additives, such as surfactants, may have an adverse effect on the antibacterial activity of preservatives. Isoeugenol is a promising candidate as a future food preservative because it works almost equally well against planktonic bacteria and biofilms. Emulsion encapsulation has potential benefits for the efficacy of isoeugenol, but the effect of encapsulation depends on the properties of food matrix in which isoeugenol is to be applied.

  4. The role of CRISPR-Cas systems in virulence of pathogenic bacteria.

    Science.gov (United States)

    Louwen, Rogier; Staals, Raymond H J; Endtz, Hubert P; van Baarlen, Peter; van der Oost, John

    2014-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes are present in many bacterial and archaeal genomes. Since the discovery of the typical CRISPR loci in the 1980s, well before their physiological role was revealed, their variable sequences have been used as a complementary typing tool in diagnostic, epidemiologic, and evolutionary analyses of prokaryotic strains. The discovery that CRISPR spacers are often identical to sequence fragments of mobile genetic elements was a major breakthrough that eventually led to the elucidation of CRISPR-Cas as an adaptive immunity system. Key elements of this unique prokaryotic defense system are small CRISPR RNAs that guide nucleases to complementary target nucleic acids of invading viruses and plasmids, generally followed by the degradation of the invader. In addition, several recent studies have pointed at direct links of CRISPR-Cas to regulation of a range of stress-related phenomena. An interesting example concerns a pathogenic bacterium that possesses a CRISPR-associated ribonucleoprotein complex that may play a dual role in defense and/or virulence. In this review, we describe recently reported cases of potential involvement of CRISPR-Cas systems in bacterial stress responses in general and bacterial virulence in particular.

  5. Automated surface-scanning detection of pathogenic bacteria on fresh produce

    Science.gov (United States)

    Horikawa, Shin; Du, Songtao; Liu, Yuzhe; Chen, I.-Hsuan; Xi, Jianguo; Crumpler, Michael S.; Sirois, Donald L.; Best, Steve R.; Wikle, Howard C.; Chin, Bryan A.

    2017-05-01

    This paper investigates the effects of surface-scanning detector position on the resonant frequency and signal amplitude of a wireless magnetoelastic (ME) biosensor for direct pathogen detection on solid surfaces. The experiments were conducted on the surface of a flat polyethylene (PE) plate as a model study. An ME biosensor (1 mm × 0.2 mm × 30 μm) was placed on the PE surface, and a surface-scanning detector was brought close and aligned to the sensor for wireless resonant frequency measurement. The position of the detector was accurately controlled by using a motorized three-axis translation system (i.e., controlled X, Y, and Z positions). The results showed that the resonant frequency variations of the sensor were -125 to +150 Hz for X and Y detector displacements of +/-600 μm and Z displacements of +100 to +500 μm. These resonant frequency variations were small compared to the sensor's initial resonant frequency (Z distance). Finally, additional experiments were conducted on the surface of cucumbers. Similar results were obtained.

  6. Control of lifespan by food bacteria, nutrient limitation and pathogenicity of food in C. elegans.

    Science.gov (United States)

    So, Shuhei; Tokumaru, Takaaki; Miyahara, Kohji; Ohshima, Yasumi

    2011-04-01

    The increased lifespan caused by food limitation has been observed in a wide range of animals including the nematode Caenorhabditis elegans. We show here that the lifespans of eat-2 and eat-5 feeding-defective mutants and a mutant of dbl-1 encoding a TGFβ ligand significantly change between the cultures fed on Escherichia coli strain OP50 or a more nutrient-rich strain HB101. On HB101 food, the eat-2, eat-5 and dbl-1 mutants show increased lifespan compared to that of the wild type. This result is probably due to nutrient limitation because the eat mutations reduce food uptake and the mutation of dbl-1 that regulates expression of several digestive enzymes leads to nutrient limitation. In contrast, the lifespans of the eat-2 and dbl-1 mutants decreased from that of the wild type on OP50 food. We found that live OP50 cells within a worm were markedly more in these mutants than in the wild type, which suggests that impaired digestion of pathogenic OP50 decreased lifespan in the eat-2 and dbl-1 mutants.

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

    Science.gov (United States)

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

    2008-09-01

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

  8. Phylogenetic analysis of the pathogenic bacteria Spiroplasma penaei based on multilocus sequence analysis.

    Science.gov (United States)

    Heres, Allan; Lightner, Donald V

    2010-01-01

    A pathogenic Spiroplasma penaei strain was isolated from the hemolymph of moribund Pacific white shrimp, Penaeus vannamei. The shrimp sample originated from a shrimp farm near Cartagena, Colombia, that was suffering from high mortalities in ponds with very low salinity and high temperatures. This new emerging disease in a marine crustacean in the Americas is described as a systemic infection. The multilocus phylogenetic analysis suggests that S. penaei strain has a terrestrial origin. Evolutionary relationship trees, based on five partial DNA sequences of 16S rDNA, 23S rDNA, 5S rDNA, gyrB, rpoB genes and two complete DNA sequences of 16S-23S rDNA and 23S-5S rDNA intergenic spacer region, were reconstructed using the distance-based Neighboring-Joining (NJ) method with Kimura-2-parameter substitution model. The NJ trees based on all DNA sequences investigated in this study positioned S. penaei in the Citri-Poulsonii clade and corroborate the observations by other investigators using the 16S rDNA gene. Pairwise genetic distance calculation between sequences of spiroplasmas showed S. penaei to be closely related to Spiroplasma insolitum and distantly related to Spiroplasma sp. SHRIMP from China.

  9. Antibacterial activity of lemongrass (Cymbopogon citratus) oil against some selected pathogenic bacterias

    Institute of Scientific and Technical Information of China (English)

    Mohd Irfan Naik; Bashir Ahmad Fomda; Ebenezar Jaykumar; Javid Ahmad Bhat

    2010-01-01

    Objective:To find the effectiveness of essential oil of lemongrass for the treatment of pathogenic organisms. Methods:Lemongrass oil was investigated for activity against Staphylococcus aureus (S. aureus) , Bacillus cereus (B. cereus) , Bacillus subtilis (B. subtilis) , Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae) and Pseudomonas aeruginosa (P. aeruginosa) , using Agar Diffusion Method and Broth Dilution Method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the Broth Dilution Method. The antibiotic susceptibility test against the test organisms was performed by Disc Diffusion Method. Results: Lemongrass was found effective against all the test organisms except P. aeruginosa. Gram positive organisms were found more sensitive to lemon grass oil as compared to gram negative organisms. The test organisms were found inhibited by Lemon grass oil at lower concentrations in Broth Dilution Method as compared to Agar Diffusion Method. Conclusions:The tested organisms, particularly gram-negative organisms had shown high resistance towards different antibiotics whereas they were found to be inhibited by lemongrass oil even at lower concentration. Thus lemongrass oil is effective against drug resistant organisms. It can be suggested that use of lemongrass oil would be helpful in the treatment of infections caused by multidrug resistant organisms.

  10. Phenotypic and genotypic characteristics of enterocin producing enterococci against pathogenic bacteria

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    Sandra Mojsova

    2015-10-01

    Full Text Available The study investigated the antimicrobial activity of 13 enterococcal strains (E. faecalis -8, E. faecium-2, E. hirae-2, E. spp.-1 isolated from our traditional cheeses against pathogen microorganisms. Also, it includes the detection of the following enterocin structural genes: enterocin A, enterocin B, enterocin P, enterocin L50A/B, bacteriocin 31, enterocin AS48, enterocin Q, enterocin EJ97 and cytolysin by using PCR method. All isolates inhibited growth of L. monocytogenes and L.innocua. One isolate had a broader antimicrobial activity. None of the isolates showed inhibitory activity against S. enteritidis, E. coli and Y. enterocolitica. The genes enterocin P, cytolysin and enterocin A were the most frequently detected structural genes among the PCR positive strains. No amplification was obtained in two strains E. faecalis-25 and E. faecalis-86. Three different genes were identified in some strains. With the exclusion of strains possessing a virulence factor, such as cytolysin, producers of more than one enterocins could be of a great technological potential as protective cultures in the cheese industry.

  11. The Role of CRISPR-Cas Systems in Virulence of Pathogenic Bacteria

    Science.gov (United States)

    Staals, Raymond H. J.; Endtz, Hubert P.; van Baarlen, Peter; van der Oost, John

    2014-01-01

    SUMMARY Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes are present in many bacterial and archaeal genomes. Since the discovery of the typical CRISPR loci in the 1980s, well before their physiological role was revealed, their variable sequences have been used as a complementary typing tool in diagnostic, epidemiologic, and evolutionary analyses of prokaryotic strains. The discovery that CRISPR spacers are often identical to sequence fragments of mobile genetic elements was a major breakthrough that eventually led to the elucidation of CRISPR-Cas as an adaptive immunity system. Key elements of this unique prokaryotic defense system are small CRISPR RNAs that guide nucleases to complementary target nucleic acids of invading viruses and plasmids, generally followed by the degradation of the invader. In addition, several recent studies have pointed at direct links of CRISPR-Cas to regulation of a range of stress-related phenomena. An interesting example concerns a pathogenic bacterium that possesses a CRISPR-associated ribonucleoprotein complex that may play a dual role in defense and/or virulence. In this review, we describe recently reported cases of potential involvement of CRISPR-Cas systems in bacterial stress responses in general and bacterial virulence in particular. PMID:24600041

  12. Occurrence of antimicrobial resistance among bacterial pathogens and indicator bacteria in pigs in different European countries from year 2002-2004; the ARBAO-II study

    NARCIS (Netherlands)

    Hendriksen, R.S.; Mevius, D.J.; Schroeter, A.; Teale, C.; Jouy, E.; Butaye, P.; Franco, A.; Utinane, A.; Amado, A.; Moreno, M.; Greko, C.; Stark, K.D.; Berghold, C.; Myllyniemi, A.L.; Hoszowski, A.; Sunde, M.; Aerestrup, F.

    2008-01-01

    Background The project "Antibiotic resistance in bacteria of animal origin ¿ II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003¿05. The aim of this project was to establish a program for the continuous monitoring of antimicrobial susceptibility of pathogenic

  13. Suppression of pecan and peach pathogens using metabolites or broths of from symbiotic bacteria obtained from the guts of entomopathogenic nematodes

    Science.gov (United States)

    Concentrated metabolites from the bacteria Xenorhabdus spp. and Photorhabdus spp. have previously been shown to suppress growth of peach and pecan pathogens in vitro, and reduce disease on detached leaves or terminals. The objectives of this study were 1) determine if bacterial broths (in addition t...

  14. ANTIBACTERIAL ACTIVITY OF GUAVA (PSIDIUM GUAJAVA L.) AND NEEM (AZADIRACHTA INDICA A. JUSS.)EXTRACTS AGAINST FOOD BORNE PATHOGENS AND SPOILAGE BACTERIA

    Science.gov (United States)

    The objective of this study was to investigate the antibacterial properties of guava (Psidium guajava) and neem (Azadirachta indica) extracts against a number of common food borne pathogens and spoilage bacteria. Screening for antibacterial activity was determined by disc diffusion assay against 21...

  15. Characterizing relationships among fecal indicator bacteria, microbial source tracking markers, and associated waterborne pathogen occurrence in stream water and sediments in a mixed land use watershed

    Science.gov (United States)

    Bed sediments of streams and rivers may store high concentrations of fecal indicator bacteria (FIB) and pathogens. Due to resuspension events, these contaminants can be mobilized into the water column and affect overall water quality. Other bacterial indicators such as microbial ...

  16. THE COMPARING OF ANTIMICROBIAL ACTIVITY OF CSN1S2 PROTEIN OF FRESH MILK AND YOGHURT GOAT BREED ETHAWAH INHIBITED THE PATHOGENIC BACTERIA

    Science.gov (United States)

    Triprisila, Lidwina Faraline; Suharjono, Suharjono; Christianto, Antonius; Fatchiyah, Fatchiyah

    2016-01-01

    Background: Goat milk is reported to have antimicrobial activity of several pathogen bacteria that contained on food materials. The research related with antimicrobial activity of Alpha-S2 casein from goat milk is relatively less than other casein components. Herein, we reported the antimicrobial activity of caprine Alpha-S2 Casein (CSN1S2) protein from Ethawah breed goat milk and yoghurt in Gram positive (Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus) and negative pathogen bacteria (Escherichia coli, Salmonella typhi and Shigella flexneri). Those bacteria were known as pathogens that caused gastrointestinal infection. Methods: Serial dilution and agar diffusion analysis with three different concentrations of caprine CSN1S2, 1.25 mg/ml, 2.5 mg/ml, and 5 mg/ml were used to test the inhibition effect of protein on the viability of bacteria cells. The inhibitory activity of caprine CSN1S2 was based on dose dependent manner. Agar diffusion analysis was showed the larger diameter of clear zone at B. cereus and S. flexneri. Results: The serial dilution analysis was shown the inhibition of almost in all groups of bacteria with concentration 5 mg/ml higher by CSN1S2 protein of goat fresh milk than yogurt. The inhibitory activity caprine CSN1S2 protein of fresh milk was shown a vary inhibition clear zone with optimal concentration 5 mg/ml, however CSN1S2 protein of goat yogurt intermediate effectively was only in gram negative bacteria. The weakness bacteria against inhibition activity caprine CSN1S2 protein was B. cereus (Gram positive) and S. flexneri (Gram negative). Meanwhile the strongest bacteria against inhibition activity caprine CSN1S2 protein was S. typhi (Gram negative), may cause in this bacteria has lipopolysaccharide prevent to interact with that protein as proper. Conclusion: This study result concluded that the caprine CSN1S2 protein has inhibition activity in opposition to pathogenic bacteria by optimal concentration 5 mg/ml in all

  17. 动物源性病原细菌的危害、监测与控制%Animal Origin Pathogenic Bacteria:Hazard,Surveillance and Control

    Institute of Scientific and Technical Information of China (English)

    王君玮

    2015-01-01

    Animal origin pathogenic bacteria are those isolated from animal samples,damaging animals and human by bacteria invasion or ingestion of their toxin. Not only can it bring economic loss and biosafety problem by causing animal diseases,but also do harm to consumers. This paper briefly introduced the main pathogenic bacteria species that impact animal health and its product safety,as well as their harm to both animals and human. Furthermore,new advance on these bacteria surveillance status was analyzed both at home and abroad. Suggestions on their control were proposed in combination with risk surveillance of pathogenic bacteria.%动物源性病原细菌,不仅引起动物发病带来经济损失和生物安全问题,而且通过污染动物源性产品,给消费者带来致病性危害。本文梳理了影响动物健康和动物源性产品安全的主要病原细菌种类及其危害,对此分析了目前国际、国内对该类病原细菌的监测管理状况,并提出了控制建议。

  18. The Investigation of Antibacterial Effects of Salvia Sahendica Extracts on Some Pathogenic Bacteria

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    H Bannazadeh Baghi

    2007-06-01

    Full Text Available Background: The salvia plant is one of the Lamiacea family members, that is being cultiurated all over the world. In Iran almost all spices of this plant could found, that are used for medical, food industry and parfumers production. Salvia sahendica genus is the member of this family, that its antibacterial effects on Klebsiella pneumonia, Staphylococcus aureus and Pseudomonas aeruginosa have been investigated. Methods: In this study are used standard strains of Pseudomonas aeruginosa (ATCC 27852 Staphylococcus aureus, (ATCC 25923 and, Klebsiella pneumonia (ATCC 3583. Salvia was provided from Tabriz mall and was powdered. Then this powder was suspended with ratio 1:10 with Metanol, Aceton, Chloroform, Hexan, Ethyl acetate and water. After 24h extractions isolated and concentrated with distillated in vacuum system. Which of bacteria were cultured to over night in Mohler Hinton agar medium, then compared with 0.5 macfarland. In continue extraction were tested by used of well assay method and then the diameter of zone measured. Experiments repeated tree times and the average of data obtained. In each of tests we had a control from special solvent. Results: Regarding to the results, all of salvia sahendica extractions showed antibacterial activity on Staphylococcus aureus, Pseudomonas aeruginosa and. That regarding Klebsiella pneumonia, Ethanol, Chloroform, Ethyl acetate, Hexan, and regarding Staphylococcus aureus Metanol, Aceton, Chloroform, Hexan, Ethyl acetate and Pseudomonas aeruginosa only Chloroform this plant has antibacterial effects. Chloroform extraction of salvia shows the most antibacterial activity (with the biggest diameter of antibacterial zone. Conclusion: Regarding the carried out study it could be noted that for inhibition and destroying Staphylococcus aureus and Klebsiella pneumonia, plants effects extraction could be used.

  19. Spectrum and antimicrobial resistance of common pathogenic bacteria isolated from patients with acute exacerbation of chronic obstructive pulmonary disease in mainland of China

    Institute of Scientific and Technical Information of China (English)

    YE Feng; HE Li-xian; CAI Bo-qiang; WEN Fu-qiang; CHEN Bai-yi; Mangunnegoro Hadiarto; CHEN Rong-chang

    2013-01-01

    Background Bacteria-induced respiratory infection has been long considered to be the major cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD).Therefore,a clear picture about the distribution and drug-resistance of pathogenic bacteria in the lower airways should be helpful for treatment of the disease.So far,data on this topic among Chinese are lacking.Methods A surveillance study was performed in consecutive patients with AECOPD at five areas in China between October 2006 and April 2008.The sputum from these patients was cultured and isolated for bacteria.Agar dilution method was used to determine the minimal inhibitory concentrations (MICs) of levofloxacin and other 15 antibiotics against these strains.Results Three hundred and fifty-nine pathogenic bacterial strains were isolated among 884 patients with AECOPD.The predominant bacteria were Pseudomonas aeruginosa (21.7%),Klebsiella pneumoniae (12.3%),Haemophilus influenzae (14.2%) and Streptococcus pneumoniae (11.7%),followed by Haemophilus parainfluenzae (9.5%),Acinetobacter baumannii (7.8%),Moraxella catarrhalis (6.4%) and Escherichia coli (3.6%).The majority of bacterial pathogens isolated in this study were susceptible to fluoroquinolones,ceftazidime,cefepime and imipenem.Conclusions Gram-negative bacilli are the leading pathogens in patients with AECOPD in China.Haemophilus parainfluenzae may be one of the most important pathogens in AECOPD.This study provides evidence for local surveillance of AECOPD pathogens and appropriate choice of antimicrobials in China.

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

    Science.gov (United States)

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

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

  1. Elaboration of highly hydrophobic polymeric surface — a potential strategy to reduce the adhesion of pathogenic bacteria?

    Energy Technology Data Exchange (ETDEWEB)

    Poncin-Epaillard, F., E-mail: fabienne.poncin-epaillard@univ-lemans.fr [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Herry, J.M. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France); Marmey, P.; Legeay, G. [CTTM, 20 rue Thalès de Milet 72000 Le Mans (France); Debarnot, D. [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Bellon-Fontaine, M.N. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France)

    2013-04-01

    Different polymeric surfaces have been modified in order to reach a high hydrophobic character, indeed the superhydrophobicity property. For this purpose, polypropylene and polystyrene have been treated by RF or μwaves CF{sub 4} plasma with different volumes, the results were compared according to the density of injected power. The effect of pretreatment such as mechanical abrasion or plasma activation was also studied. The modified surfaces were shown as hydrophobic, or even superhydrophobic depending of defects density. They were characterized by measurement of wettability and roughness at different scales, i.e. macroscopic, mesoscopic and atomic. It has been shown that a homogeneous surface at the macroscopic scale could be heterogeneous at lower mesoscopic scale. This was associated with the crystallinity of the material. The bioadhesion tests were performed with Gram positive and negative pathogenic strains: Listeria monocytogenes, Pseudomonas aeruginosa and Hafnia alvei. They have demonstrated an antibacterial efficiency of very hydrophobic and amorphous PS treated for all strains tested and a strain-dependent efficiency with modified PP surface being very heterogeneous at the mesoscopic scale. Thus, these biological results pointed out not only the respective role of the surface chemistry and topography in bacterial adhesion, but also the dependence on the peaks and valley distribution at bacteria dimension scale. Highlights: ► Simple, eco-friendly modification of polymers leading to highly hydrophobic property ► Plasma treatment inducing surface fluorination and roughness ► Study of non-adhesion of different types of bacteria onto such polymeric surfaces ► Dependence of their non-adhesion on surface topography whatever their characteristics.

  2. Sediment composition influences spatial variation in the abundance of human pathogen indicator bacteria within an estuarine environment.

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    Tracy L Perkins

    Full Text Available Faecal contamination of estuarine and coastal waters can pose a risk to human health, particularly in areas used for shellfish production or recreation. Routine microbiological water quality testing highlights areas of faecal indicator bacteria (FIB contamination within the water column, but fails to consider the abundance of FIB in sediments, which under certain hydrodynamic conditions can become resuspended. Sediments can enhance the survival of FIB in estuarine environments, but the influence of sediment composition on the ecology and abundance of FIB is poorly understood. To determine the relationship between sediment composition (grain size and organic matter and the abundance of pathogen indicator bacteria (PIB, sediments were collected from four transverse transects of the Conwy estuary, UK. The abundance of culturable Escherichia coli, total coliforms, enterococci, Campylobacter, Salmonella and Vibrio spp. in sediments was determined in relation to sediment grain size, organic matter content, salinity, depth and temperature. Sediments that contained higher proportions of silt and/or clay and associated organic matter content showed significant positive correlations with the abundance of PIB. Furthermore, the abundance of each bacterial group was positively correlated with the presence of all other groups enumerated. Campylobacter spp. were not isolated from estuarine sediments. Comparisons of the number of culturable E. coli, total coliforms and Vibrio spp. in sediments and the water column revealed that their abundance was 281, 433 and 58-fold greater in sediments (colony forming units (CFU/100g when compared with the water column (CFU/100ml, respectively. These data provide important insights into sediment compositions that promote the abundance of PIB in estuarine environments, with important implications for the modelling and prediction of public health risk based on sediment resuspension and transport.

  3. Is Predominant Clonal Evolution a Common Evolutionary Adaptation to Parasitism in Pathogenic Parasitic Protozoa, Fungi, Bacteria, and Viruses?

    Science.gov (United States)

    Tibayrenc, M; Ayala, F J

    2017-01-01

    We propose that predominant clonal evolution (PCE) in microbial pathogens be defined as restrained recombination on an evolutionary scale, with genetic exchange scarce enough to not break the prevalent pattern of clonal population structure. The main features of PCE are (1) strong linkage disequilibrium, (2) the widespread occurrence of stable genetic clusters blurred by occasional bouts of genetic exchange ('near-clades'), (3) the existence of a "clonality threshold", beyond which recombination is efficiently countered by PCE, and near-clades irreversibly diverge. We hypothesize that the PCE features are not mainly due to natural selection but also chiefly originate from in-built genetic properties of pathogens. We show that the PCE model obtains even in microbes that have been considered as 'highly recombining', such as Neisseria meningitidis, and that some clonality features are observed even in Plasmodium, which has been long described as panmictic. Lastly, we provide evidence that PCE features are also observed in viruses, taking into account their extremely fast genetic turnover. The PCE model provides a convenient population genetic framework for any kind of micropathogen. It makes it possible to describe convenient units of analysis (clones and near-clades) for all applied studies. Due to PCE features, these units of analysis are stable in space and time, and clearly delimited. The PCE model opens up the possibility of revisiting the problem of species definition in these organisms. We hypothesize that PCE constitutes a major evolutionary strategy for protozoa, fungi, bacteria, and viruses to adapt to parasitism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. The missing link: Bordetella petrii is endowed with both the metabolic versatility of environmental bacteria and virulence traits of pathogenic Bordetellae

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    Schneiker-Bekel Susanne

    2008-09-01

    Full Text Available Abstract Background Bordetella petrii is the only environmental species hitherto found among the otherwise host-restricted and pathogenic members of the genus Bordetella. Phylogenetically, it connects the pathogenic Bordetellae and environmental bacteria of the genera Achromobacter and Alcaligenes, which are opportunistic pathogens. B. petrii strains have been isolated from very different environmental niches, including river sediment, polluted soil, marine sponges and a grass root. Recently, clinical isolates associated with bone degenerative disease or cystic fibrosis have also been described. Results In this manuscript we present the results of the analysis of the completely annotated genome sequence of the B. petrii strain DSMZ12804. B. petrii has a mosaic genome of 5,287,950 bp harboring numerous mobile genetic elements, including seven large genomic islands. Four of them are highly related to the clc element of Pseudomonas knackmussii B13, which encodes genes involved in the degradation of aromatics. Though being an environmental isolate, the sequenced B. petrii strain also encodes proteins related to virulence factors of the pathogenic Bordetellae, including the filamentous hemagglutinin, which is a major colonization factor of B. pertussis, and the master virulence regulator BvgAS. However, it lacks all known toxins of the pathogenic Bordetellae. Conclusion The genomic analysis suggests that B. petrii represents an evolutionary link between free-living environmental bacteria and the host-restricted obligate pathogenic Bordetellae. Its remarkable metabolic versatility may enable B. petrii to thrive in very different ecological niches.

  5. Metabolic Environments and Genomic Features Associated with Pathogenic and Mutualistic Interactions between Bacteria and Plants is accepted for publication in MPMI

    Energy Technology Data Exchange (ETDEWEB)

    Karpinets, Tatiana V [ORNL; Park, Byung H [ORNL; Syed, Mustafa H [ORNL; Klotz, Martin G [University of North Carolina, Charlotte; Uberbacher, Edward C [ORNL

    2014-01-01

    Most bacterial symbionts of plants are phenotypically characterized by their parasitic or matualistic relationship with the host; however, the genomic characteristics that likely discriminate mutualistic symbionts from pathogens of plants are poorly understood. This study comparatively analyzed the genomes of 54 plant-symbiontic bacteria, 27 mutualists and 27 pathogens, to discover genomic determinants of their parasitic and mutualistic nature in terms of protein family domains, KEGG orthologous groups, metabolic pathways and families of carbohydrate-active enzymes (CAZymes). We further used all bacteria with sequenced genomesl, published microarrays and transcriptomics experimental datasets, and literature to validate and to explore results of the comparison. The analysis revealed that genomes of mutualists are larger in size and higher in GC content and encode greater molecular, functional and metabolic diversity than the investigated genomes of pathogens. This enriched molecular and functional enzyme diversity included constructive biosynthetic signatures of CAZymes and metabolic pathways in genomes of mutualists compared with catabolic signatures dominant in the genomes of pathogens. Another discriminative characteristic of mutualists is the co-occurence of gene clusters required for the expression and function of nitrogenase and RuBisCO. Analysis of previously published experimental data indicate that nitrogen-fixing mutualists may employ Rubisco to fix CO2 not in the canonical Calvin-Benson-Basham cycle but in a novel metabolic pathway, here called Rubisco-based glycolysis , to increase efficiency of sugar utilization during the symbiosis with plants. An important discriminative characteristic of plant pathogenic bacteria is two groups of genes likely encoding effector proteins involved in host invasion and a genomic locus encoding a putative secretion system that includes a DUF1525 domain protein conserved in pathogens of plants and of other organisms. The

  6. Effects of biochar on reducing the abundance of oxytetracycline, antibiotic resistance genes, and human pathogenic bacteria in soil and lettuce.

    Science.gov (United States)

    Duan, Manli; Li, Haichao; Gu, Jie; Tuo, Xiaxia; Sun, Wei; Qian, Xun; Wang, Xiaojuan

    2017-05-01

    Antibiotics and antibiotic resistance genes (ARGs) in soil can affect human health via the food chain. Biochar is a soil amendment but its impacts on ARGs and the microbial communities associated with soil and vegetables are unclear. Therefore, we established three lettuce pot culture experiments, i.e., O300: 300 mg/kg oxytetracycline (OTC), BO300: 300 mg/kg OTC + 2% biochar, and a control without OTC or biochar. We found that under BO300, the relative abundances of ARGs were reduced by 51.8%, 43.4%, and 44.1% in lettuce leaves, roots, and soil, respectively, compared with O300. intI1 was highly abundant in soil and lettuce, and it co-occurred with some ARGs (tetW, ermF, and sul1). Redundancy analysis and network analysis indicated that the bacterial community succession was the main mechanism that affected the variations in ARGs and intI1. The reduction of Firmicutes due to the biochar treatment of soil and lettuce was the main factor responsible for the removal of tetracycline resistance genes in leaves. Biochar application led to the disappearance of human pathogenic bacteria (HPB), which was significantly correlated with the abundances of ermF and ermX. In summary, biochar is an effective farmland amendment for reducing the abundances of antibiotics, ARGs, and HPB in order to ensure the safety of vegetables and protect human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Screening and Scoring of Antimicrobial and Biological Activities of Italian Vulnerary Plants against Major Oral Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Gianmaria F. Ferrazzano

    2013-01-01

    Full Text Available This study aims to evaluate the activity of Italian vulnerary plants against the most important oral pathogenic bacteria. This estimate was accomplished through a fivefold process: (a a review of ethnobotanical and microbiological data concerning the Italian vulnerary plants; (b the development of a scoring system to rank the plants; (c the comparative assessment of microbiological properties; (d the assessment of potential cytotoxic effects on keratinocyte-like cells and gingival fibroblasts in culture by XTT cell viability assay; (e clinical evaluation of the most suitable plant extract as antibacterial agent in a home-made mouthwash. The study assays hexane (H, ethanol (E, and water (W extracts from 72 plants. The agar diffusion method was used to evaluate the activity against Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Actinomyces viscosus. Twenty-two plants showed appreciable activity. The extracts showing the strongest antibacterial power were those from Cotinus coggygria Scop., Equisetum hyemale L., Helichrysum litoreum Guss, Juniperus communis L., and Phyllitis scolopendrium (L. Newman subsp. scolopendrium. The potential cytotoxic effect of these extracts was assessed. On the basis of these observations, a mouth-rinse containing the ethanolic extract of H. litoreum has been tested in vivo, resulting in reduction of the salivary concentration of S. mutans.

  8. Behavior of metals, pathogen parasites, and indicator bacteria in sewage effluents during biological treatment by activated sludge.

    Science.gov (United States)

    Tonani, K A A; Julião, F C; Trevilato, T M B; Takayanagui, A M M; Bocio, Ana; Domingo, Jose L; Segura-Muñoz, Susana I

    2011-11-01

    The purpose of this study was to evaluate the behavior of metals, pathogen parasites, and indicator bacteria in sewage effluents during biological treatment by activated sludge in a wastewater treatment plant in Ribeirão Preto (WTP-RP), Sao Paulo, Brazil. The evaluation was done during a period of 1 year. Results showed that metal concentrations in treated effluents decreased, reaching concentrations according to those established by national regulations. The activated sludge process at the WTP-RP promoted a partial removal of parasites considered as possible indicators according to the WHO guidelines. Reduction factors varied between 18.2% and 100% for agents such as Endolimax nana, Entamoeba coli, Entamoeba hystolitica, Giardia sp., Ancylostoma sp., Ascaris sp., Fasciola hepatica, and Strongyloides stercoralis. A removal was also observed in total and fecal coliforms quantification. The present study represents an initial evaluation of the chemical and microbiological removal capacity of the WTP-RP. The results should be of interest for the authorities responsible for the environmental health at municipal, regional, national, and international levels.

  9. DESIGN NOTE: Development of an integrated solid-state generator for light inactivation of food-related pathogenic bacteria

    Science.gov (United States)

    Ghasemi, Z.; Macgregor, S.; Anderson, J.; Lamont, Y.

    2003-06-01

    This paper is concerned with the design and performance of a fully integrated solid-state Marx generator, which has been developed to drive a UV flashlamp for use in microbiological inactivation. The generator has an output voltage rating of 3 kV and a peak current rating of 2 kA, although the modular approach taken allows for a number of voltage and current ratings to be achieved. The generator is constructed using a number of series- and parallel-connected 1.2 kV insulated-gate-bipolar-transistor (IGBT) switched capacitors. Switching of the IGBT modules is controlled by an optical signal. Details are given of how the optimum IGBT gate-drive circuit is achieved using optical components and a pass-through wire to provide the required energies for individual IGBT modules. The generator is demonstrated as the driver of a UV flashlamp used for inactivation of food-related pathogenic bacteria such as E. coli and Salmonella. The performance of the Marx generator over a period of 106 pulses is examined, along with the changes that occur in the spectrum of the UV flashlamp during the same period.

  10. Identification of Opportunistic Pathogenic Bacteria in Drinking Water Samples of Different Rural Health Centers and Their Clinical Impacts on Humans

    Directory of Open Access Journals (Sweden)

    Pavan Kumar Pindi

    2013-01-01

    Full Text Available International drinking water quality monitoring programs have been established in order to prevent or to reduce the risk of contracting water-related infections. A survey was performed on groundwater-derived drinking water from 13 different hospitals in the Mahabubnagar District. A total of 55 bacterial strains were isolated which belonged to both gram-positive and gram-negative bacteria. All the taxa were identified based on the 16S rRNA gene sequence analysis based on which they are phylogenetically close to 27 different taxa. Many of the strains are closely related to their phylogenetic neighbors and exhibit from 98.4 to 100% sequence similarity at the 16S rRNA gene sequence level. The most common group was similar to Acinetobacter junii (21.8% and Acinetobacter calcoaceticus (10.9% which were shared by 7 and 5 water samples, respectively. Out of 55 isolates, only 3 isolates belonged to coliform group which are Citrobacter freundii and Pantoea anthophila. More than half (52.7%, 29 strains of the phylogenetic neighbors which belonged to 12 groups were reported to be pathogenic and isolated from clinical specimens. Out of 27 representative taxa are affiliated have eight representative genera in drinking water except for those affiliated with the genera Exiguobacterium, Delftia, Kocuria, and Lysinibacillus.

  11. Gold nanoparticles synthesized by Brassica oleracea (Broccoli) acting as antimicrobial agents against human pathogenic bacteria and fungi

    Science.gov (United States)

    Piruthiviraj, Prakash; Margret, Anita; Krishnamurthy, Poornima Priyadharsani

    2016-04-01

    Production of antimicrobial agents through the synthesis of gold nanoparticles using green technology has been extensively made consistent by various researchers; yet, this study uses the flower bud's aqueous extracts of Brassica oleracea (Broccoli) as a reducing agent for chloroauric acid (1 mM). After 30 min of incubation, synthesis of gold nanoparticles (AuNps) was observed by a change in extract color from pale yellow to purple color. Synthesis of AuNps was confirmed in UV-visible spectroscopy at the range of approximately 560 nm. The SEM analysis showed the average nanoparticles size of 12-22 nm. The antimicrobial activity of AuNps was analyzed by subjecting it to human pathogenic bacteria (Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumonia) and fungi (Aspergillus flavus, Aspergillus niger and Candida albicans) using disc diffusion method. The broccoli-synthesized AuNps showed the efficient antibacterial and antifungal activity of above-mentioned microbes. It was confirmed that AuNps have the best antimicrobial agent compared to the standard antibiotics (Gentamicin and Fluconazole). When the concentrations of AuNps were increased (10, 25, and 50 µg/ml), the sensitivity zone also increased for all the tested microbes. The synthesized AuNps are capable of rendering high antimicrobial efficacy and, hence, have a great potential in the preparation of drugs used against major bacterial and fungal diseases in humans.

  12. A new hybrid bacteriocin, Ent35–MccV, displays antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria

    Science.gov (United States)

    Acuña, Leonardo; Picariello, Gianluca; Sesma, Fernando; Morero, Roberto D.; Bellomio, Augusto

    2012-01-01

    Bacteriocins and microcins are ribosomally synthesized antimicrobial peptides that are usually active against phylogenetically related bacteria. Thus, bacteriocins are active against Gram-positive while microcins are active against Gram-negative bacteria. The narrow spectrum of action generally displayed by bacteriocins from lactic acid bacteria represents an important limitation for the application of these peptides as clinical drugs or as food biopreservatives. The present study describes the design and expression of a novel recombinant hybrid peptide combining enterocin CRL35 and microcin V named Ent35–MccV. The chimerical bacteriocin displayed antimicrobial activity against enterohemorrhagic Escherichia coli and Listeria monocytogenes clinical isolates, among other pathogenic bacteria. Therefore, Ent35–MccV may find important applications in food or pharmaceutical industries. PMID:23650575

  13. Characterization of the microbial community in a lotic environment to assess the effect of pollution on nitrifying and potentially pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    JD Medeiros

    Full Text Available This study aimed to investigate microbes involved in the nitrogen cycle and potentially pathogenic bacteria from urban and rural sites of the São Pedro stream. Water samples were collected from two sites. A seasonal survey of bacterial abundance was conducted. The dissolved nutrient content was analysed. PCR and FISH analysis were performed to identify and quantify microbes involved in the nitrogen cycle and potentially pathogenic bacteria. The seasonal survey revealed that the bacterial abundance was similar along the year on the rural area but varied on the urban site. Higher concentration of dissolved nutrients in the urban area indicated a eutrophic system. Considering the nitrifying microbes, the genus Nitrobacter was found, especially in the urban area, and may act as the principal bacteria in converting nitrite into nitrate at this site. The molecular markers napA, amoA, and nfrA were more accumulated at the urban site, justifying the higher content of nutrients metabolised by these enzymes. Finally, high intensity of amplicons from Enterococcus, Streptococcus, Bacteroides/Prevotella/Porphyromonas, Salmonella, S. aureus, P. aeruginosa and the diarrheagenic lineages of E. coli were observed at the urban site. These results indicate a change in the structure of the microbial community imposed by anthrophic actions. The incidence of pathogenic bacteria in aquatic environments is of particular importance to public health, emphasising the need for sewage treatment to minimise the environmental impacts associated with urbanisation.

  14. Frost-related dieback of willows. Comparison of epiphytically and endophytically isolated bacteria from different Salix clones, with emphasis on ice nucleation activity, pathogenic properties and seasonal variation

    Energy Technology Data Exchange (ETDEWEB)

    Cambours, M.A.; Nejad, P.; Ramstedt, M. [Swedish University of Agricultural Sciences, Uppsala (Sweden). Plant Pathology and Biocontrol Unit; Granhall, U. [Swedish University of Agricultural Sciences, Uppsala (Sweden). Department of Microbiology

    2005-01-01

    Swedish Salix plantation for biomass production have been suffering severe dieback during the past 10 years, possibly due to the combination of frost and bacterial disease. As opposed to summer and winter, spring and autumn are periods when epiphytic populations of ice nucleation active (INA) bacteria are generally high. The culturable bacterial floras from stems of diseased plant of four Salix viminalis clones were compared in spring and autumn. Both epiphytic and endophytic bacteria were isolated (i.e. from plant surface and from tissues beneath the bark, respectively), characterised and tested for ice nucleating activity and pathogenicity. Some strains were also identified with BIOLOG and 16S rRNA. Endophytically isolated communities were generally more stable than epiphytes, both in number of isolates and type of bacteria. More types were found in autumn than in spring the same year, although the total number of strains isolated was rather constant. In contrast, more strains (and a higher percentage of the total community) expressed ice nucleating activity in spring than in autumn. The overall number of pathogenic strains remained stable but their proportion among the community tested on plants increased. A close relationship was observed between the dieback rates in the field and the percentage of pathogenic strains found in the different clones. The dominating bacterial type isolated, Sphingomonas spp., also contained the highest percentage of ice nucleation active pathogenic strains. (author)

  15. Quantitative analyses of the bacterial microbiota of rearing environment, tilapia and common carp cultured in earthen ponds and inhibitory activity of its lactic acid bacteria on fish spoilage and pathogenic bacteria.

    Science.gov (United States)

    Kaktcham, Pierre Marie; Temgoua, Jules-Bocamdé; Ngoufack Zambou, François; Diaz-Ruiz, Gloria; Wacher, Carmen; Pérez-Chabela, María de Lourdes

    2017-02-01

    The present study aimed to evaluate the bacterial load of water, Nile Tilapia and common Carp intestines from earthen ponds, isolate lactic acid bacteria (LAB) and assess their antimicrobial activity against fish spoilage and pathogenic bacteria. Following enumeration and isolation of microorganisms the antimicrobial activity of the LAB isolates was evaluated. Taxonomic identification of selected antagonistic LAB strains was assessed, followed by partial characterisation of their antimicrobial metabolites. Results showed that high counts (>4 log c.f.u ml(-1) or 8 log c.f.u g(-1)) of total aerobic bacteria were recorded in pond waters and fish intestines. The microbiota were also found to be dominated by Salmonella spp., Vibrio spp., Staphylococcus spp. and Escherichia coli. LAB isolates (5.60%) exhibited potent direct and extracellular antimicrobial activity against the host-derived and non host-derived spoilage and pathogenic bacteria. These antagonistic isolates were identified and Lactococcus lactis subsp. lactis was found as the predominant (42.85%) specie. The strains displayed the ability to produce lactic, acetic, butyric, propionic and valeric acids. Bacteriocin-like inhibitory substances with activity against Gram-positive and Gram-negative (Vibrio spp. and Pseudomonas aeruginosa) bacteria were produced by three L. lactis subsp. lactis strains. In this study, the LAB from the microbiota of fish and pond water showed potent antimicrobial activity against fish spoilage or pathogenic bacteria from the same host or ecological niche. The studied Cameroonian aquatic niche is an ideal source of antagonistic LAB that could be appropriate as new fish biopreservatives or disease control agents in aquaculture under tropical conditions in particular or worldwide in general.

  16. 新生儿感染性肺炎的病原菌状况分析%Investigation of pathogenic bacteria and antibiotic susceptibility in neonatal infective pneumonia

    Institute of Scientific and Technical Information of China (English)

    卓少宏; 伍成峰; 马兴灶; 詹世产

    2012-01-01

    Objective To investigate the pathogenic bateria of neonatal infective pneumonia in Shantou area. Method The identification of bacteria and susceptibility test were performed by AMS VITEK-60. Reslut Gram-negative bacteria were the prominent pathogens, which accounted for 92.81% (142/153) of the pathogens in neonatal infective pneumonia. The most common pathogens were Klebsialla pneumonia. There were less pathogens of Gram-positive bacteria found in the neonatal infective pneumonia. The resistance rates of Gram-negative bacteria to cephalosporins and aminoglycosides were significantly higher than to imipenem and fluroguinlones. Conclusion Klebsialla pneumonia is the prominent pathogen of neonatal infective pneumonia in Shantou area. The first choices of antibiotics in treating Gram-negative bacteria infection are imipenem, cefotetan and ciprofloxacin. Use of antibiotics in clinical therapy should be based on the results of susceptibility of pathogens.%目的 了解本地区新生儿感染性肺炎的病原菌的菌种、构成比及耐药情况,探索临床合理选用抗生素.方法 细菌鉴定及药敏试验采用VITEK-60全自动细菌鉴定仪.结果 本地区新生儿感染性肺炎的病原菌主要为革兰阴性杆菌(92.81%),其中以肺炎克雷伯菌最为常见,革兰阳性球菌感染较少(7.19%).革兰阴性杆菌对头孢二代、三代和氨基糖苷类抗生素的耐药率均较高,对喹诺酮类抗生素耐药率较低.亚胺培南具有良好的抗菌活性.结论 肺炎克雷伯菌是本地区新生儿感染性肺炎的主要病原菌.经验性治疗用药可首选亚胺培南、头孢替坦、环丙沙星等,建议临床根据药敏结果选用抗生素.

  17. Antimicrobial Effect of Filipendula ulmaria Plant Extract Against Selected Foodborne Pathogenic and Spoilage Bacteria in Laboratory Media, Fish Flesh and Fish Roe Product

    Directory of Open Access Journals (Sweden)

    Charalampos Proestos

    2011-01-01

    Full Text Available Water-methanol extract from Filipendula ulmaria contains a variety of phenolic compounds, such as caffeic, p-coumaric and vanillic acid, myricetin, etc, which demonstrate antibacterial activity. Monitoring this activity in the broth using absorbance measurements showed that species of the Enterobacteriaceae family were more resistant than other Gram-negative and Gram-positive bacteria tested. Acidic environment enhanced the antibacterial activity of Filipendula ulmaria extract when it was tested against Salmonella Enteritidis PT4 and Listeria monocytogenes Scott A. The efficacy of Filipendula ulmaria extract against selected foodborne psychrotrophic bacteria was also tested using solid laboratory media and low incubation temperatures for better simulation of food preservation conditions. Higher concentrations of the extract, compared to minimum inhibitory concentration determined in the broth, were needed for satisfactory inhibition of spoilage bacteria. Potential use of Filipendula ulmaria extract as natural food preservative was also examined against natural spoilage flora and inoculated pathogenic bacteria on fish flesh and fish roe product (tarama salad. No significant differences of viable populations of spoilage or pathogenic bacteria were found between the treated samples and controls. Further trials of Filipendula ulmaria extract should be carried out in acidic foods with low fat and protein content, supplemented with additional adjuncts, in order to explore its potential as effective natural food antimicrobial agent.

  18. Purification and proteomics of pathogen-modified vacuoles and membranes

    Directory of Open Access Journals (Sweden)

    Jo-Ana eHerweg

    2015-06-01

    Full Text Available Certain pathogenic bacteria adopt an intracellular lifestyle and proliferate in eukaryotic host cells. The intracellular niche protects the bacteria from cellular and humoral components of the mammalian immune system, and at the same time, allows the bacteria to gain access to otherwise restricted nutrient sources. Yet, intracellular protection and access to nutrients comes with a price, i.e. the bacteria need to overcome cell-autonomous defense mechanisms, such as the bactericidal endocytic pathway. While a few bacteria rupture the early phagosome and escape into the host cytoplasm, most intracellular pathogens form a distinct, degradation-resistant and replication-permissive membranous compartment. Intracellular bacteria that form unique pathogen vacuoles include Legionella, Mycobacterium, Chlamydia, Simkania and Salmonella species. In order to understand the formation of these pathogen niches on a global scale and in a comprehensive and quantitative manner, an inventory of compartment-associated host factors is required. To this end, the intact pathogen compartments need to be isolated, purified and biochemically characterized. Here, we review recent progress on the isolation and purification of pathogen-modified vacuoles and membranes, as well as their proteomic characterization by mass spectrometry and different validation approaches. These studies provide the basis for further investigations on the specific mechanisms of pathogen-driven compartment formation.

  19. Service Learning Course in Which Undergraduates and Middle School Students Investigate Levels of Pathogen Indicating Bacteria in Beach Sand

    Science.gov (United States)

    Imamura, G.; Mika, K.; Lin, T.; Lee, C.; Lin, C.; Jay, J.

    2007-12-01

    Service-learning is a pedagogy that combines academic rigor with activities that address human and community needs. Over the past three years, we have developed a service-learning course that involves UCLA students working with 6th graders in an economically disadvantaged neighborhood to address issues of environmental science and health. This past year UCLA students conducted a research project in collaboration with a middle school class to investigate levels of pathogen-indicating organisms in beach sand near the Santa Monica pier. All students were taught necessary methods in class by the UCLA professor, and then met at the field site. Fieldwork involved collection of water and sand samples from various locations, extraction of bacteria from sand by shaking with buffer and decanting, and addition of sample to growth media that allow quantification of two organisms, Escherichia coli and enterococci. These organisms are typically used to indicate fecal contamination of water. Methods were straightforward and were accomplished by the 6th graders with only modest supervision by the UCLA students. Results showed extremely high levels of pathogen indicating organisms in the vicinity of a diverted stormdrain, indicating a continuing problem with the diversion. Levels decreased with distance away from the stormdrain, indicating migration of the organisms from the site of the diversion. UCLA students then visited the sixth grade classroom to help the sixth graders create Powerpoint posters including statement of hypotheses, graphs of the results, pictures of the entire process, and conclusions. Middle school students then visited UCLA to tour the campus and present their posters at a poster session hosted by the Center for Embedded Networked Sensing at UCLA. Desired outcomes at the 6th grade level included: 1) increased interest in science; 2) greater knowledge of and interest in attending college; and 3) enhanced knowledge of and feeling of political empowerment

  20. Application of loop-mediated isothermal amplification (LAMP) assay for the rapid diagnosis of pathogenic bacteria in clinical sputum specimens of acute exacerbation of COPD (AECOPD).

    Science.gov (United States)

    Zhang, Wei; Chen, Chuanhui; Cui, Jian; Bai, Wei; Zhou, Jing

    2015-01-01

    The present study explores the application of LAMP for rapid diagnosis of pathogenic bacteria in clinical sputum specimens of AECOPD as compared with conventional sputum culturing method. 120 sputum specimens of AECOPD patients, 46 sputum specimens of healthy controls, as well as 166 serum specimens as negative controls, were evaluated by LAMP assay using primers of eight typical respiratory pathogens. No cross-reactivity was observed in these negative control species using LAMP assay. The lower detection limit of LAMP assay was approximately 10(3) copies. 25 cases (20.8%) were detected at least one positive bacteria species by conventional sputum culturing method, while 73 cases (60.8%) were tested positive in LAMP assay. Moreover, compared with sputum culture, bacterial titers results of LAMP assay were more consistent with FEV1/FVC value of AECOPD patients. These results indicated that the sensitivity of LAMP assay was significantly higher than that of sputum culturing method.

  1. Thionin-like peptides from Capsicum annuum fruits with high activity against human pathogenic bacteria and yeasts.

    Science.gov (United States)

    Taveira, Gabriel B; Mathias, Luciana S; da Motta, Olney V; Machado, Olga L T; Rodrigues, Rosana; Carvalho, André O; Teixeira-Ferreira, André; Perales, Jonas; Vasconcelos, Ilka M; Gomes, Valdirene M

    2014-01-01

    Plants defend themselves against pathogens with production of antimicrobial peptides (AMPs). Herein we describe the discovery of a new antifungal and antibacterial peptide from fruits of Capsicum annuum that showed similarity to an already well characterized family of plant AMPs, thionins. Other fraction composed of two peptides, in which the major peptide also showed similarity to thionins. Among the obtained fractions, fraction 1, which is composed of a single peptide of 7 kDa, was sequenced by Edman method and its comparative sequence analysis in database (nr) showed similarity to thionin-like peptides. Tests against microorganisms, fraction 1 presented inhibitory activity to the cells of yeast Saccharomyces cerevisiae, Candida albicans, and Candida tropicalis and caused growth reduction to the bacteria species Escherichia coli and Pseudomonas aeruginosa. Fraction 3 caused inhibitory activity only for C. albicans and C. tropicalis. This fraction was composed of two peptides of ∼7 and 10 kDa, and the main protein band correspondent to the 7 kDa peptide, also showed similarity to thionins. This plasma membrane permeabilization assay demonstrates that the peptides present in the fractions 1 and 3 induced c