Download the Free Unbound MEDLINE PubMed App to your smartphone or tablet.
Available for iPhone, iPad, iPod touch, and Android.
- Detection and prevalence of pathogenic Yersinia enterocolitica in refrigerated and frozen dairy products by duplex PCR and dot hybridization targeting the virF and ail genes. [JOURNAL ARTICLE]
- J Dairy Sci 2014 Sep 10.
Pathogenic Yersinia enterocolitica is involved in yersiniosis through expression of chromosome-borne or plasmid-borne virulence factors. Yersinia enterocolitica is a cold-tolerant pathogen frequently isolated from refrigerated or frozen foods. However, little attention has been focused on the prevalence of pathogenic Y. enterocolitica in refrigerated or frozen dairy samples in China. In this study, we developed a new duplex PCR targeting the plasmid-borne virF gene and chromosome-borne ail gene for detection of pathogenic Y. enterocolitica isolates. We established a detection limit for the duplex PCR of 6.5 × 10(2) cfu/mL in artificially contaminated dairy samples. In addition, the duplex PCR could detect directly 4.5 to 5.7 cfu of Y. enterocolitica in 5 mL of brain heart infusion broth after 6 h of enrichment at 28°C. A newly developed dot hybridization assay further confirmed specificity of the duplex PCR for detection of virulent Y. enterocolitica. Furthermore, 13 Y. enterocolitica and 5 pathogenic strains, from 88 commercial frozen or refrigerated dairy products, were detected successfully by the China National Standard method (GB/T4789.8-2008) and the duplex PCR, respectively. Finally, biotypes and serotypes of pathogenic Y. enterocolitica strains were further characterized. The duplex PCR developed here is reliable for large-scale screening, routine monitoring, and risk assessment of pathogenic Y. enterocolitica in refrigerated or frozen dairy products.
- Unique virulence properties of Yersinia enterocolitica O:3 - An emerging zoonotic pathogen using pigs as preferred reservoir host. [JOURNAL ARTICLE]
- Int J Med Microbiol 2014 Jul 25.
Enteropathogenic Yersinia enterocolitica bioserotype 4/O:3 are the most frequent cause of human yersiniosis worldwide with symptoms ranging from mild diarrhea to severe complications of mesenteric lymphadenitis, liver abscesses and postinfectious extraintestinal sequelae. The main reservoir host of 4/O:3 strains are pigs, which represent a substantial disease-causing potential for humans, as they are usually asymptomatic carriers. Y. enterocolitica O:3 initiates infections by tight attachment to the intestinal mucosa. Colonization of the digestive tract is frequently followed by invasion of the intestinal layer primarily at the follicle-associated epithelium, allowing the bacteria to propagate in the lamina propria and disseminate into deeper tissues. Molecular characterization of Y. enterocolitica O:3 isolates led to the identification of (i) alternative virulence and fitness factors and (ii) small genetic variations which cause profound changes in their virulence gene expression pattern (e.g. constitutive expression of the primary invasion factor InvA). These changes provoke a major difference in the virulence properties, i.e. reduced colonization of intestinal tissues in mice, but improved long-term colonization in the pig intestine. Y. enterocolitica O:3 strains cause also a considerably lower level of proinflammatory cytokine IL-8 and higher levels of the anti-inflammatory cytokine IL-10 in porcine primary macrophages, as compared to murine macrophages, which could contribute to limiting inflammation, immunopathology and severity of the infection in pigs.
- Evaluation of different enrichment methods for pathogenic Yersinia species detection by real time PCR. [Journal Article]
- BMC Vet Res 2014; 10(1):192.
Yersiniosis is a zoonotic disease reported worldwide. Culture and PCR based protocols are the most common used methods for detection of pathogenic Yersinia species in animal samples. PCR sensitivity could be increased by an initial enrichment step. This step is particularly useful in surveillance programs, where PCR is applied to samples from asymptomatic animals. The aim of this study was to evaluate the improvement in pathogenic Yersinia species detection using a suitable enrichment method prior to the real time PCR (rtPCR). Nine different enrichment protocols were evaluated including six different broth mediums (CASO, ITC, PSB, PBS, PBSMSB and PBSSSB).The analysis of variance showed significant differences in Yersinia detection by rtPCR according to the enrichment protocol used. These differences were higher for Y. pseudotuberculosis than for Y. enterocolitica. In general, samples incubated at lower temperatures yielded the highest detection rates. The best results were obtained with PBSMSB and PBS2. Application of PBSMSB protocol to free-ranging wild board samples improved the detection of Y. enterocolitica by 21.2% when compared with direct rtPCR. Y. pseudotuberculosis detection was improved by 10.6% when results obtained by direct rtPCR and by PBSMSB enrichment before rtPCR were analyzed in combination.The data obtained in the present study indicate a difference in Yersinia detection by rtPCR related to the enrichment protocol used, being PBSMSB enrichment during 15 days at 4°C and PBS during 7 days at 4°C the most efficient. The use of direct rtPCR in combination with PBSMSB enrichment prior to rtPCR resulted in an improvement in the detection rates of pathogenic Yersinia in wild boar and could be useful for application in other animal samples.
- Efficacy of lipopolysaccharide antigen of Yersinia ruckeri in rainbow trout by intraperitoneal and bath immersion administration. [JOURNAL ARTICLE]
- Res Vet Sci 2014 Aug 7.
In this study, Intraperitoneal (IP) and bath immersion (BI) vaccine trials were conducted in fish with a mean weight of 6.3 g. Rainbow trout vaccinated with lipopolysaccharide (LPS) was 50 mg/L protein concentration and challenged by IP injection with 9.8 × 10(6) cell/ml of Yersinia ruckeri at 45 days post-immunization had a relative percent survival (RPS). To obtain an effective bath immersion vaccine against yersiniosis, LPS preparation was obtained from the Y. ruckeri and with the LPS antigen. After 28 and 60 days vaccinated fish with first and second immunizations by LPS were challenged via intraperitoneal injection with 9.8 × 10(6) cell/ml of Y. ruckeri for evaluating the mortality rates and calculating the relative percentage of survival (RPS). RPS value of experimental groups, which was significantly (P < 0.05) larger than that of the control group.
- Low-shear force associated with modeled microgravity and spaceflight does not similarly impact the virulence of notable bacterial pathogens. [JOURNAL ARTICLE]
- Appl Microbiol Biotechnol 2014 Aug 23.
As their environments change, microbes experience various threats and stressors, and in the hypercompetitive microbial world, dynamism and the ability to rapidly respond to such changes allow microbes to outcompete their nutrient-seeking neighbors. Viewed in that light, the very difference between microbial life and death depends on effective stress response mechanisms. In addition to the more commonly studied temperature, nutritional, and chemical stressors, research has begun to characterize microbial responses to physical stress, namely low-shear stress. In fact, microbial responses to low-shear modeled microgravity (LSMMG), which emulates the microgravity experienced in space, have been studied quite widely in both prokaryotes and eukaryotes. Interestingly, LSMMG-induced changes in the virulence potential of several Gram-negative enteric bacteria, e.g., an increased enterotoxigenic Escherichia coli-mediated fluid secretion in ligated ileal loops of mice, an increased adherent invasive E. coli-mediated infectivity of Caco-2 cells, an increased Salmonella typhimurium-mediated invasion of both epithelial and macrophage cells, and S. typhimurium hypervirulence phenotype in BALB/c mice when infected by the intraperitoneal route. Although these were some examples where virulence of the bacteria was increased, there are instances where organisms became less virulent under LSMMG, e.g., hypovirulence of Yersinia pestis in cell culture infections and hypovirulence of methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, and Listeria monocytogenes in a Caenorhabditis elegans infection model. In general, a number of LSMMG-exposed bacteria (but not all) seemed better equipped to handle subsequent stressors such as osmotic shock, acid shock, heat shock, and exposure to chemotherapeutics. This mini-review primarily discusses both LSMMG-induced as well as bona fide spaceflight-specific alterations in bacterial virulence potential, demonstrating that pathogens' responses to low-shear forces vary dramatically. Ultimately, a careful characterization of numerous bacterial pathogens' responses to low-shear forces is necessary to evaluate a more complete picture of how this physical stress impacts bacterial virulence since a "one-size-fits-all" response is clearly not the case.
- Tuberculosis and the risk of infection with other intracellular bacteria: a population-based study. [JOURNAL ARTICLE]
- Epidemiol Infect 2014 Aug 22.:1-9.
SUMMARY Persons who develop tuberculosis (TB) may have subtle immune defects that could predispose to other intracellular bacterial infections (ICBIs). We obtained data on TB and five ICBIs (Chlamydia trachomatis, Salmonella spp., Shigella spp., Yersinia spp., Listeria monocytogenes) reported to the Tennessee Department of Health, USA, 2000-2011. Incidence rate ratios (IRRs) comparing ICBIs in persons who developed TB and ICBIs in the Tennessee population, adjusted for age, sex, race and ethnicity were estimated. IRRs were not significantly elevated for all ICBIs combined [IRR 0·87, 95% confidence interval (CI) 0·71-1·06]. C. trachomatis rate was lowest in the year post-TB diagnosis (IRR 0·17, 95% CI 0·04-0·70). More Salmonella infections occurred in extrapulmonary TB compared to pulmonary TB patients (IRR 14·3, 95% CI 1·67-122); however, this appeared to be related to HIV co-infection. TB was not associated with an increased risk of other ICBIs. In fact, fewer C. trachomatis infections occurred after recent TB diagnosis. Reasons for this association, including reduced exposure, protection conferred by anti-TB drugs or macrophage activation by Mycobacterium tuberculosis infection warrant further investigation.
- Prevalence of yersinia species in traditional and commercial dairy products in isfahan province, iran. [Journal Article]
- Jundishapur J Microbiol 2014 Apr; 7(4):e9249.
Yersinia species, especially Yersinia enterocolitica, are considered as the most prevalent milk-borne pathogens. Several serological and molecular techniques have been developed for rapid and safe diagnosis of yersiniosis.This study was carried out to assess the prevalence rate of Yersinia species, especially Y. enterocolitica, in milk and dairy products in Isfahan province, Iran.A total of 285 commercial and traditional dairy products as well as 267 pasteurized and raw milk samples were collected during one year. The samples were studied by culturing and the positive-culture samples were investigated using PCR techniques.The results of culture showed that 52 (9.42%) and 28 (5.07%) of the total 552 milk and dairy samples were positive for presences of Yersinia species and Y. enterocolitica, respectively. Totally, 24 of 28 Y. enterocolitica isolates by culture were positive in PCR test (4.59%). Raw cow milk and traditional cheese had the highest prevalence of Yersinia species and Y. enterocolitica, respectively. There were no positive results for pasteurized cow milk, raw camel milk, commercial ice cream, commercial cheese, yoghurt, Doogh, butter and curd. Yersinia species and Y. enterocolitica had the highest prevalence in autumn (15.15% and 10.6%, respectively). Significant differences regarding P < 0.05 were observed between the presences of Yersinia species and Y. enterocolitica in various samples and seasons.Sanitation and pasteurization are the best ways to increase the microbial quality and particularly decrease the load of Yersinia species. The ability of Yersinia species to growth in Doogh, yoghurt, curd and butter is very low.
- Yersiniosis in poland in 2012. [Journal Article]
- Przegl Epidemiol 2014; 68(2):235-8.
The aim of this study is to assess the epidemiology of yersiniosis in Poland in 2012 compared to previous years.We reviewed surveillance data published in the annual bulletin "Infectious diseases and poisonings in Poland" from 2007 to 2012 (MP Czarkowski et al., NIH and GIS) and individual yersiniosis case reports from 2012 sent by the Sanitary-Epidemiological Stations. Additionally, we used data from the Department of Demographic Surveys in Central Statistical Office.In Poland in 2012 a total of 231 yersiniosis cases were reported including 201 cases of intestinal and 30 cases of extraintestinal yersiniosis; 61.9% of patients were hospitalized. The incidence rate was 0.6 per 100 000 inhabitants. No deaths related to the disease were reported. Intestinal yersiniosis was manifested mostly by following symptoms: diarrhoea (87%), fever (76%), abdominal pain (47%) and vomiting (31%). The most affected group in intestinal infections were children younger than 4 years - 145 cases (72% of all cases). Extraintestinal form of infection was more common than in 2011 (19 cases) and usually involved symptoms from the osteoarticular system, noted in 90% of patients. Similarly to the previous year (2011) most cases of yersiniosis were reported from Mazowieckie province (103), no case has been reported from Świętokrzyskie province. Serological types of Yersinia enterocolitica were identified in 120 cases (52%): serotype O3 (96.7%), O8 (2.5%) and O9 (<1%). There were two household outbreaks. In comparison to previous years the total number of cases caused by serotype O8 has significantly decreased - from 55 cases in 2011 to 3 cases in 2012.A large percentage (48%) of unknown Yersinia serotypes is a consequence, that physicians do not always request serotyping in routine diagnostics. Reporting cases of extraintestinal yersiniosis from only few provinces may suggest that the real number of infections remains underreported.
- Whole-animal chemical screen identifies colistin as a new immunomodulator that targets conserved pathways. [Journal Article]
- MBio 2014; 5(4)
The purpose of this study was to take advantage of the nematode Caenorhabditis elegans to perform a whole-animal chemical screen to identify potential immune activators that may confer protection against bacterial infections. We identified 45 marketed drugs, out of 1,120 studied compounds, that are capable of activating a conserved p38/PMK-1 mitogen-activated protein kinase pathway required for innate immunity. One of these drugs, the last-resort antibiotic colistin, protected against infections by the Gram-negative pathogens Yersinia pestis and Pseudomonas aeruginosa but not by the Gram-positive pathogens Enterococcus faecalis and Staphylococcus aureus. Protection was independent of the antibacterial activity of colistin, since the drug was administered prophylactically prior to the infections and it was also effective against antibiotic-resistant bacteria. Immune activation by colistin is mediated not only by the p38/PMK-1 pathway but also by the conserved FOXO transcription factor DAF-16 and the transcription factor SKN-1. Furthermore, p38/PMK-1 was found to be required in the intestine for immune activation by colistin. Enhanced p38/PMK-1-mediated immune responses by colistin did not reduce the bacterial burden, indicating that the pathway plays a role in the development of host tolerance to infections by Gram-negative bacteria.The innate immune system represents the front line of our defenses against invading microorganisms. Given the ever-increasing resistance to antibiotics developed by bacterial pathogens, the possibility of boosting immune defenses represents an interesting, complementary approach to conventional antibiotic treatments. Here we report that the antibiotic colistin can protect against infections by a mechanism that is independent of its microbicidal activity. Prophylactic treatment with colistin activates a conserved p38/PMK-1 pathway in the intestine that helps the host better tolerate a bacterial infection. Since p38/PMK-1-mediated immune responses appear to be conserved from plants to mammals, colistin may also activate immunity in higher organisms, including humans. Antibiotics with immunomodulatory properties have the potential of improving the long-term outcome of patients with chronic infectious diseases.
- The first imported human case of Yersinia pseudotuberculosis serotype O1 septicemia presents with acute appendicitis-like syndrome in Taiwan. [Journal Article]
- J Formos Med Assoc 2014 Sep; 113(9):656-9.
Human nonplague yersiniosis occurs more commonly in temperate regions than in tropical or subtropical regions. In Taiwan, which is located in a subtropical region of Southeast Asia, only environmental isolates and human infection of Yersinia enterocolitica were reported, but a human case of Y. pseudotuberculosis infection had not been identified. We report the first person with Y. pseudotuberculosis serotype O1 septicemia who presented with acute appendicitis-like syndrome and who was probably contracted the infection via ingestion of raw foods in a barbecue restaurant in Japan.