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- Detection of Yersinia enterocolitica in food: an overview. [JOURNAL ARTICLE]
- Eur J Clin Microbiol Infect Dis 2014 Nov 20.
Yersinia enterocolitica is a gastrointestinal pathogen which causes yersiniosis, an illness characterized by diarrhea, ileitis, and mesenteric lymphadenitis. Y. enterocolitica is transmitted via the feco-oral route by the consumption of contaminated food or water. Several phenotypic and genotypic methods have been developed to reliably detect Y. enterocolitica in food. However, the source of infection of many recently reported foodborne outbreaks remains obscure. The detection of this pathogen in food is a challenging task, since it shares similarities with other enteric bacteria. The presence of other microorganisms in the food samples makes it even more difficult to identify this slow-growing pathogen. Therefore, the present-day emphasis is on the development of sensitive, easily automated methods suitable for in-situ detection, allowing quick and cost-effective characterization of food samples. This review summarizes and compares the currently available cultural, immunological, and molecular methods, particularly in relation to their specific merits or demerits when implemented for the detection of Y. enterocolitica in food.
- Serological characterization of the enterobacterial common antigen substitution of the lipopolysaccharide of Yersinia enterocolitica O:3. [JOURNAL ARTICLE]
- Microbiology 2014 Nov 18.
Enterobacterial common antigen (ECA) is a polysaccharide present in all members of Enterobacteriaceae anchored either via phosphatidylglycerol (PG) or lipopolysaccharide (LPS) to the outer leaflet of outer membrane (ECAPG and ECALPS, respectively). Only the latter form is ECA-immunogenic. We earlier demonstrated that Yersinia enterocolitica O:3 and its rough (O-specific polysaccharide-negative) mutants were ECA-immunogenic implicating that they contained ECALPS however, it was not known which part of the LPS core region was involved in ECA binding. To address this, we used a set of three deep-rough LPS mutants for rabbit immunizations. The obtained polyvalent antisera were: (i) analyzed for the presence of anti-LPS and anti-ECA antibodies; (ii) treated with caprylic acid (CA) to precipitate IgM antibodies and protein aggregates; and (iii) adsorbed with live ECA-negative bacteria to obtain specific anti-ECA antisera. We could demonstrate the presence of antibodies specific for both ECAPG and ECALPS in all antisera obtained. Both CA treatment and adsorption with ECA-negative bacteria efficiently removed anti-LPS antibodies resulting in specific anti-ECA sera. The LPS of the ECALPS positive deepest-rough mutant contained only lipid A and 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) residues of the inner core suggesting that ECALPS was linked to the Kdo-region of LPS in Y. enterocolitica O:3.
- Bacterial programming of host responses: coordination between type I interferon and cell death. [Journal Article, Review]
- Front Microbiol 2014.:545.
During mammalian infection, bacteria induce cell death from an extracellular or intracellular niche that can protect or hurt the host. Data is accumulating that associate type I interferon (IFN) signaling activated by intracellular bacteria with programmed death of immune effector cells and enhanced virulence. Multiple pathways leading to IFN-dependent host cell death have been described, and in some cases it is becoming clear how these mechanisms contribute to virulence. Yet common mechanisms of IFN-enhanced bacterial pathogenesis are not obvious and no specific interferon stimulated genes have yet been identified that cause sensitivity to pathogen-induced cell death. In this review, we will summarize some bacterial infections caused by facultative intracellular pathogens and what is known about how type I IFN signaling may promote the replication of extracellular bacteria rather than stimulate protection. Each of these pathogens can survive phagocytosis but their intracellular life cycles are very different, they express distinct virulence factors and trigger different pathways of immune activation and crosstalk. These differences likely lead to widely varying amounts of type I IFN expression and a different inflammatory environment, but these may not be important to the pathologic effects on the host. Instead, each pathogen induces programmed cell death of key immune cells that have been sensitized by the activation of the type I IFN response. We will discuss how IFN-dependent host cell death may increase host susceptibility and try to understand common pathways of pathogenesis that lead to IFN-enhanced bacterial virulence.
- Interrelationship between type three secretion system and metabolism in pathogenic bacteria. [REVIEW]
- Front Cell Infect Microbiol 2014.:150.
Before the advent of molecular biology methods, studies of pathogens were dominated by analyses of their metabolism. Development of molecular biology techniques then enabled the identification and functional characterisation of the fascinating toolbox of virulence factors. Increasing, genomic and proteomic approaches form the basis for a more systemic view on pathogens' functions in the context of infection. Re-emerging interest in the metabolism of pathogens and hosts further expands our view of infections. There is increasing evidence that virulence functions and metabolism of pathogens are extremely intertwined. Type three secretion systems (T3SSs) are major virulence determinants of many Gram-negative pathogens and it is the objective of this review to illustrate the intertwined relationship between T3SSs and the metabolism of the pathogens deploying them.
- Isolation of Pathogenic Yersinia enterocolitica 1B/O:8 from Apodemus Mice in Japan. [JOURNAL ARTICLE]
- J Wildl Dis 2014 Nov 7.
Abstract Yersinia enterocolitica was isolated from 15.7% (88/560) of wild rodents captured in 15 prefectures in Japan. Prevalences by rodent species were 18.0% (70/388) in Japanese field mice (Apodemus speciosus), 20% (14/71) in small Japanese field mice (Apodemus argenteus), and 11% (4/38) in gray red-backed vole (Myodes rufocanus bedfordiae), suggesting that these rodent species are important reservoirs of Y. enterocolitica. Although most of the isolates were identified as biotype 1A, the pathogenic bioserotype 1B/O:8 was detected in one of the A. speciosus and in three of the A. argenteus captured in Aomori Prefecture. It is suggested that Apodemus mice may be an important reservoir of Y. enterocolitica, and that there are foci of the pathogenic bioserotype 1B/O:8 in Aomori Prefecture, because human sporadic cases by the serotype have been reported in this prefecture.
- Immunopotentiation for bacterial biodefense. [Journal Article]
- Curr Top Med Chem 2014; 14(18):2115-26.
Activation of the innate immune system can enhance resistance to a variety of bacterial and viral infections. In situations where the etiological agent of disease is unknown, such as a bioterror attack, stimulation of innate immunity may be particularly useful as induced immune responses are often capable of providing protection against a broad range of pathogens. In particular, the threat of an intentional release of a highly virulent bacterial pathogen that is either intrinsically resistant to antibiotics, or has been weaponized via the introduction of antibiotic resistance, makes immunopotentiation an attractive complementary or alternative strategy to enhance resistance to bacterial biothreat agents. Francisella tularensis, Yersinia pestis, Bacillus anthracis, and Burkholderia mallei or pseudomallei can all be easily disseminated via the respiratory route and infections can result in high mortality rates. Therefore, there has been a marked increase in research on immunotherapeutics against these Tier 1 select agents over the last 10 years that will be covered in this review. In addition, immunopotentiation against non-Tier 1 select agents such as Brucella spp., and Coxiella burnetii has also been studied and will be reviewed here. In particular, we will focus on cellular targets, such as toll-like receptors (TLRs), carbohydrate receptors and cytokine receptors, which have been exploited by immunomodulatory regimens that confer broad-spectrum protection against virulent bacterial pathogens.
- [Development of molecular PCR-RFLP test for identification of the epidemic strain of Y. enterocolitica bioserotype 1B/O8 circulating in Poland since 2004]. [English Abstract, Journal Article, Research Support, Non-U.S. Gov't]
- Med Dosw Mikrobiol 2014; 66(2):89-98.
Highly pathogenic Y. enterocolitica bioserotype 1B/O8 is considered to be an important etiological agent of yersiniosis in Poland. Infections caused by Y. enterocolitica 1B/O8 became an important public health problem in Poland, especially because of their high potential of virulence and the unknown source of the bacteria. Y. enterocolitica 1B/O8 isolates recovered in Poland are genetically highly related and constitute single epidemic sensu stricto strain. The aim of the present study was to develop a time- and money-effective molecular assay for rapid identification of pathogenic Y. enterocolitica 1B/O8 isolates belonging to the epidemic strain.In the first stage we performed a multiplex-PCR for four genetic markers: ail, ystA, irp1 and 16S rDNA sequence. In the next stage we designed a duplex-PCR-RFLP assay with BtsI endonuclease to detect/identify specific variant of an ysrR gene that is characteristic for epidemic strain of Y. enterocolitica 1B/O8 strain. The assay was tested against a panel of a consisted of a variety Yersinia enterocolitica and Y. pseudotuberculosis strains.All the tested Y. enterocolitica 1B/O8 strains were positive for all the genetic markers in multiplex-PCR assay what distinguished them from other tested Yersinia strains. In duplex-PCR-RFLP test all tested isolates of the epidemic strain were negative for ysrR digestion with BtsI endonuclease, while all tested reference strains of Y. enterocolitica 1B/O8 were positive.The assay developed in this study was two-stage/two-step molecular test efficiently distinguishing wild-type and the epidemic Y. enterocolitica 1B/O8 strain. Such test can be a useful screening tool for clinical, veterinary and food diagnostics, as well as for the purposes of epidemiological investigation.
- Fast and sensitive detection of enteropathogenic Yersinia by immunoassays. [JOURNAL ARTICLE]
- J Clin Microbiol 2014 Oct 29.
Yersinia enterocolitica and Yersinia pseudotuberculosis, the two enteropathogenic Yersinia species for humans are worldwide distributed and are causing frequently diarrhea to inhabitants of temperate and cold countries. Yersinia enterocolitica is a major cause of foodborne disease, by consumption of contaminated pork meat further associated substantial economic cost. However, investigating enteropathogenic Yersinia is hardly performed routinely in clinical laboratories because of their specific growth characteristics, which make difficult their isolation from stools samples. Moreover, current isolation procedures are time consuming and expensive, thus leading to underestimated incidence of enteric yersiniosis, inappropriate prescriptions of antibiotic treatments and unnecessary appendectomies. The main objective of the study was to develop fast, sensitive, specific and easy-to-use immunoassays, useful for both human and veterinary diagnosis. Monoclonal antibodies (mAbs) directed against Y. enterocolitica bioserotypes 2/O:9 and 4/O:3 and Y. pseudotuberculosis serotypes I and III were produced. Pairs of mAbs were selected by testing their specificity and affinity toward enteropathogenic Yersinia and other commonly found enterobacteria. Pairs of mAbs were selected to develop highly sensitive enzyme immunoassays (EIA) and lateral flow immunoassays (LFI or dipsticks) convenient for rapid diagnostic purpose. The limit of detection of the EIAs ranged from 3.2 x 10(3) cfu/ml to 8.8 x 10(4) cfu/ml for pathogenic serotypes I and III of Y. pseudotuberculosis and pathogenic bioserotypes 2/O:9 and 4/O:3 of Y. enterocolitica and ranged for the LFIs from 10(5) cfu/ml to 10(6) cfu/ml. A similar limit of detection was observed for artificially contaminated human feces.
- Complete genome sequence of bacteriophage vB_YenP_AP5 which infects Yersinia enterocolitica of serotype O:3. [Journal Article, Research Support, Non-U.S. Gov't]
- Virol J 2014.:188.
Bacteriophage vB_YenP_AP5 is a lytic bacteriophage capable of infecting Yersinia enterocolitica strains of serotype O:3, an epidemiologically significant serotype within this bacterial species that causes yersiniosis in humans. This work describes the complete genome sequence of this phage.The genome consists of linear double-stranded DNA of 38,646 bp, with direct terminal repeats of 235 bp in length, and a GC content of 50.7%. There are 45 open reading frames which occupy 89.9% of the genome. Most of the proteins encoded by this virus exhibit sequence similarity to Yersinia phage φYeO3-12 and Salmonella phage φSG-JL2 proteins.Genomic and morphological analyses place the bacteriophage vB_YenP_AP5 in the T7likevirus genus of the subfamily Autographivirinae within the family Podoviridae.
- Detection of Rickettsia felis, Rickettsia typhi, Bartonella Species and Yersinia pestis in Fleas (Siphonaptera) from Africa. [Journal Article]
- PLoS Negl Trop Dis 2014 Oct; 8(10):e3152.
Little is known about the presence/absence and prevalence of Rickettsia spp, Bartonella spp. and Yersinia pestis in domestic and urban flea populations in tropical and subtropical African countries.Fleas collected in Benin, the United Republic of Tanzania and the Democratic Republic of the Congo were investigated for the presence and identity of Rickettsia spp., Bartonella spp. and Yersinia pestis using two qPCR systems or qPCR and standard PCR. In Xenopsylla cheopis fleas collected from Cotonou (Benin), Rickettsia typhi was detected in 1% (2/199), and an uncultured Bartonella sp. was detected in 34.7% (69/199). In the Lushoto district (United Republic of Tanzania), R. typhi DNA was detected in 10% (2/20) of Xenopsylla brasiliensis, and Rickettsia felis was detected in 65% (13/20) of Ctenocephalides felis strongylus, 71.4% (5/7) of Ctenocephalides canis and 25% (5/20) of Ctenophthalmus calceatus calceatus. In the Democratic Republic of the Congo, R. felis was detected in 56.5% (13/23) of Ct. f. felis from Kinshasa, in 26.3% (10/38) of Ct. f. felis and 9% (1/11) of Leptopsylla aethiopica aethiopica from Ituri district and in 19.2% (5/26) of Ct. f. strongylus and 4.7% (1/21) of Echidnophaga gallinacea. Bartonella sp. was also detected in 36.3% (4/11) of L. a. aethiopica. Finally, in Ituri, Y. pestis DNA was detected in 3.8% (1/26) of Ct. f. strongylus and 10% (3/30) of Pulex irritans from the villages of Wanyale and Zaa.Most flea-borne infections are neglected diseases which should be monitored systematically in domestic rural and urban human populations to assess their epidemiological and clinical relevance. Finally, the presence of Y. pestis DNA in fleas captured in households was unexpected and raises a series of questions regarding the role of free fleas in the transmission of plague in rural Africa, especially in remote areas where the flea density in houses is high.