- Differential detection of pathogenic Yersinia spp. by fluorescence in situ hybridization. [Journal Article]
- FMFood Microbiol 2017; 62:39-45
- Yersinia enterocolitica, Y. pseudotuberculosis and Y. pestis are pathogens of major medical importance, which are responsible for a considerable number of infections every year. The detection of thes...
Yersinia enterocolitica, Y. pseudotuberculosis and Y. pestis are pathogens of major medical importance, which are responsible for a considerable number of infections every year. The detection of these species still relies on cultural methods, which are slow, labour intensive and often hampered by the presence of high amounts of accompanying flora. In this study, fluorescence in situ hybridization (FISH) was used to develop a fast, sensitive and reliable alternative to detect viable bacteria in food. For this purpose, highly specific probes targeting the 16S and 23S ribosomal RNA were employed to differentially detect each of the three species. In order to enable the differentiation of single nucleotide polymorphisms (SNPs), suitable competitor oligonucleotides and locked nucleic acids (LNAs) were used. Starved cells still showed a strong signal and a direct viable count (DVC) approach combined with FISH optimized live/dead discrimination. Sensitivity of the FISH test was high and even a single cell per gram of spiked minced pork meat could be detected within a day, demonstrating the applicability to identify foodborne hazards at an early stage. In conclusion, the established FISH tests proved to be promising tools to compensate existing drawbacks of the conventional cultural detection of these important zoonotic agents.
- YPTB3816 of Yersinia pseudotuberculosis strain IP32953 is a virulence-related metallo-oligopeptidase. [Journal Article]
- BMBMC Microbiol 2016 Nov 25; 16(1):282
- CONCLUSIONS: The results of this study provide valuable contribution to the investigation of bacterial peptidases in general, and that of metallo-oligopeptidases in particular. This is the first study demonstrating that opdA in Yersinia pseudotuberculsosis is required for pathogenicity. The data reported are important for better understanding of the role of OpdA-like enzymes in pathogenesis in bacterial infections. Characterisation of this protein may serve as a basis for the development of novel antibacterials based on specific inhibition of this peptidase activity.
- Flagellin-mediated protection against intestinal Yersinia pseudotuberculosis infection does not require interleukin-22. [Journal Article]
- IIInfect Immun 2016 Nov 21
- Signaling through toll-like receptors (TLRs), the main receptors in innate immunity, is essential for the defense of mucosal surfaces. It was previously shown that systemic TLR5 stimulation by bacter...
Signaling through toll-like receptors (TLRs), the main receptors in innate immunity, is essential for the defense of mucosal surfaces. It was previously shown that systemic TLR5 stimulation by bacterial flagellin induces an immediate, transient interleukin-22 (IL-22)-dependent antimicrobial response to bacterial or viral infections of the mucosa. This process was dependent on the activation of type 3 innate lymphoid cells (ILCs). The objective of the present study was to analyze the effects of flagellin treatment in a murine model of oral infection with Yersinia pseudotuberculosis (an invasive, Gram-negative, enteropathogenic bacterium that targets the small intestine). We found that systemic administration of flagellin significantly increased the survival rate after intestinal infection (but not systemic infection) by Y. pseudotuberculosis This protection was associated with a low bacterial count in the gut and the spleen. In contrast, no protection was afforded by administration of the TLR4 agonist lipopolysaccharide - suggesting the presence of a flagellin-specific effect. Lastly, we found that TLR5- and MyD88-mediated signaling was required for the protective effects of flagellin, whereas neither lymphoid cells nor IL-22 were involved.
- Investigation of and Response to 2 Plague Cases, Yosemite National Park, California, USA, 2015. [Journal Article]
- EIEmerg Infect Dis 2016; 22(12)
- In August 2015, plague was diagnosed for 2 persons who had visited Yosemite National Park in California, USA. One case was septicemic and the other bubonic. Subsequent environmental investigation ide...
In August 2015, plague was diagnosed for 2 persons who had visited Yosemite National Park in California, USA. One case was septicemic and the other bubonic. Subsequent environmental investigation identified probable locations of exposure for each patient and evidence of epizootic plague in other areas of the park. Transmission of Yersinia pestis was detected by testing rodent serum, fleas, and rodent carcasses. The environmental investigation and whole-genome multilocus sequence typing of Y. pestis isolates from the patients and environmental samples indicated that the patients had been exposed in different locations and that at least 2 distinct strains of Y. pestis were circulating among vector-host populations in the area. Public education efforts and insecticide applications in select areas to control rodent fleas probably reduced the risk for plague transmission to park visitors and staff.
- Yersiniosis in Poland in 2014 [Journal Article]
- PEPrzegl Epidemiol 2016; 70(3):367-374
- CONCLUSIONS: A significant decrease of serologically identified cases of yersinia observed in 2014. could be explained by the test for Yersinia not being reimbursed by routine health care insurance. Reporting cases of extraintestinal yersiniosis from only few voivodeships suggests that the real number of infections remains underreported. In 2014 significantly higher number of cases of Yersinia infection occurred during the second and third quarter of the year. Seasonality of yersiniosis in 2014 differs from seasonality in 2013. However, it was similar to the seasonality observed in previous years (2009-2012).
- Modeling of spatio-temporal variation in plague incidence in Madagascar from 1980 to 2007. [Journal Article]
- SSSpat Spatiotemporal Epidemiol 2016; 19:125-135
- Plague is an infectious disease caused by the bacterium Yersinia pestis, which, during the fourteenth century, caused the deaths of an estimated 75-200 million people in Europe. Plague epidemics stil...
Plague is an infectious disease caused by the bacterium Yersinia pestis, which, during the fourteenth century, caused the deaths of an estimated 75-200 million people in Europe. Plague epidemics still occur in Africa, Asia and South America. Madagascar is today one of the most endemic countries, reporting nearly one third of the human cases worldwide from 2004 to 2009. The persistence of plague in Madagascar is associated with environmental and climatic conditions. In this paper we present a case study of the spatio-temporal analysis of plague incidence in Madagascar from 1980 to 2007. We study the relationship of plague with temperature and precipitation anomalies, and with elevation. A joint spatio-temporal analysis of the data proves to be computationally intractable. We therefore develop a spatio-temporal log-Gaussian Cox process model, but then carry out marginal temporal and spatial analyses. We also introduce a spatially discrete approximation for Gaussian processes, whose parameters retain a spatially continuous interpretation. We find evidence of a cumulative effect, over time, of temperature anomalies on plague incidence, and of a very high relative risk of plague occurrence for locations above 800 m in elevation. Our approach provides a useful modeling framework to assess the relationship between exposures and plague risk, irrespective of the spatial resolution at which the latter has been recorded.
- Site-Directed Mutagenesis and Its Application in Studying the Interactions of T3S Components. [Journal Article]
- MMMethods Mol Biol 2017; 1531:11-31
- Type III secretion systems are a prolific virulence determinant among Gram-negative bacteria. They are used to paralyze the host cell, which enables bacterial pathogens to establish often fatal infec...
Type III secretion systems are a prolific virulence determinant among Gram-negative bacteria. They are used to paralyze the host cell, which enables bacterial pathogens to establish often fatal infections-unless an effective therapeutic intervention is available. However, as a result of a catastrophic rise in infectious bacteria resistant to conventional antibiotics, these bacteria are again a leading cause of worldwide mortality. Hence, this report describes a pDM4-based site-directed mutagenesis strategy that is assisting in our foremost objective to better understand the fundamental workings of the T3SS, using Yersinia as a model pathogenic bacterium. Examples are given that clearly document how pDM4-mediated site-directed mutagenesis has been used to establish clean point mutations and in-frame deletion mutations that have been instrumental in identifying and understanding the molecular interactions between components of the Yersinia type III secretion system.
- RAPID IDENTIFICATION OF THE ETIOLOGICAL FACTORS CAUSING DIARRHEAL DISEASES. [Journal Article]
- GMGeorgian Med News 2016; (258):89-92
- The main objective of this investigation was to develop and pilot a real-time Polymerase Chain Reaction (rt-PCR) diagnostic system for rapid and simultaneous identification of pathogens with a partic...
The main objective of this investigation was to develop and pilot a real-time Polymerase Chain Reaction (rt-PCR) diagnostic system for rapid and simultaneous identification of pathogens with a particular emphasis on diarrheal disease diagnostics. The diarrheal diseases were selected as a target for the pilot because they constitute a primary public health priority in Georgia and worldwide. The product developed by our research team "Neo_PCR_Diagnostics" represents an original system for the identification of pathogens associated with gastrointestinal tract infections and diarrhea. The advantages of the proposed technology over existing conventional methods include the ability of simultaneous identification of multiple pathogens and the detection of pathogenic agents directly from the fecal samples. For the evaluation of the new diagnostic system, stool samples were collected at collaborating hospitals and clinics and analyzed by real-time PCR using the Neo_PCR_Diagnostic system. The selection of the pathogens for detection was based on their epidemiological and clinical importance. The following bacterial pathogens were targets for detection: Salmonella spp., Campylobacter spp., Shigella spp., Clostridium difficile (Toxin A/B), Escherichia coli (ETEC, STEC and O157), Yersinia enterocolitica and Vibrio cholerae. The following viral pathogens were studied: adenoviruses, rotaviruses and noroviruses. Genetic material (DNA) of the following parasites were targets in our study: Giardia lamblia, Entamoeba histolitica and Cryptosporidium spp. We also compared the results obtained by our molecular technology with the conventional methods - bacterial culture (for bacterial growth) and ELISA (for bacterial toxins). For viral and parasitic pathogens, comparison tests were performed with immunochromatographic assays for direct detection of antigens in the stool samples or with the data obtained by use of home-made end-point PCR (where available). Advantages of the proposed technology over existing conventional technologies include the ability of simultaneous identification of diarrheal infections by multiple pathogens. The proposed test system allows the detection of pathogenic agents directly from the fecal samples and can be completed within one working day. In general, the spectrum of pathogens detected by our approach was wider than those detected by the conventional methods used in the clinical setting, taking into consideration the list of pathogenic agents requisitioned by physicians within the framework of the routine clinical visit. Given these promising results, Neo_PCR_Diagnostics test performance and accuracy may be sufficient for use in molecular microbiological diagnostics in clinical and/or research settings.
- Bacteriophages of Yersinia pestis. [Journal Article]
- AEAdv Exp Med Biol 2016; 918:361-375
- Bacteriophage play many varied roles in microbial ecology and evolution. This chapter collates a vast body of knowledge and expertise on Yersinia pestis phages, including the history of their isolati...
Bacteriophage play many varied roles in microbial ecology and evolution. This chapter collates a vast body of knowledge and expertise on Yersinia pestis phages, including the history of their isolation and classical methods for their isolation and identification. The genomic diversity of Y. pestis phage and bacteriophage islands in the Y. pestis genome are also discussed because all phage research represents a branch of genetics. In addition, our knowledge of the receptors that are recognized by Y. pestis phage, advances in phage therapy for Y. pestis infections, the application of phage in the detection of Y. pestis, and clustered regularly interspaced short palindromic repeats (CRISPRs) sequences of Y. pestis from prophage DNA are all reviewed here.
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- Immunology of Yersinia pestis Infection. [Journal Article]
- AEAdv Exp Med Biol 2016; 918:273-292
- As a pathogen of plague, Yersinia pestis caused three massive pandemics in history that killed hundreds of millions of people. Yersinia pestis is highly invasive, causing severe septicemia which, if ...
As a pathogen of plague, Yersinia pestis caused three massive pandemics in history that killed hundreds of millions of people. Yersinia pestis is highly invasive, causing severe septicemia which, if untreated, is usually fatal to its host. To survive in the host and maintain a persistent infection, Yersinia pestis uses several stratagems to evade the innate and the adaptive immune responses. For example, infections with this organism are biphasic, involving an initial "noninflammatory" phase where bacterial replication occurs initially with little inflammation and following by extensive phagocyte influx, inflammatory cytokine production, and considerable tissue destruction, which is called "proinflammatory" phase. In contrast, the host also utilizes its immune system to eliminate the invading bacteria. Neutrophil and macrophage are the first defense against Yersinia pestis invading through phagocytosis and killing. Other innate immune cells also play different roles, such as dendritic cells which help to generate more T helper cells. After several days post infection, the adaptive immune response begins to provide organism-specific protection and has a long-lasting immunological memory. Thus, with the cooperation and collaboration of innate and acquired immunity, the bacterium may be eliminated from the host. The research of Yersinia pestis and host immune systems provides an important topic to understand pathogen-host interaction and consequently develop effective countermeasures.