Yersinia enterocolitica: Epidemiological Studies and Outbreaks

Abstract

Yersinia enterocolitica is the most common bacteriological cause of gastrointestinal disease in many developed and developing countries. Although contaminated food is the main source of human infection due to Y. enterocolitica, animal reservoir and contaminated environment are also considered as other possible infection sources for human in epidemiological studies. Molecular based epidemiological studies are found to be more efficient in investigating the occurrence of human pathogenic Y. enterocolitica in natural samples, in addition to conventional culture based studies.

Figure 1

Occurrence of Y. enterocolitica in natural samples.

Figure 2

Methods used for epidemiological studies of Y. enterocolitica-1. Selective enrichment methods [43]; selective agar media [11]; cold enrichment method [57]; biochemical & serological identification methods [–63]. (PBS: Phosphate buffered saline; PSB: Phosphate-buffered saline with sorbitol and bile salts; MRB: Modified Rappaport broth containing magnesium chloride, malachite green, and carbenicillin; ITC: Modified Rappaport base supplemented with irgasan, ticarcillin, and potassium chlorate; BOS: Bile-oxalate-sorbose medium; TSB: Tryptic soy broth; TSPN: TSB with polymyxin and novobiocin; CIN: Cefsulodin-irgasan-novobiocin; SSDC: Salmonella-Shigella deoxycolate calcium chloride; VYE: Virulent Yersinia enterocolitica; SSI: Statens Serum Institute, Copenhagen, Denmark, enteric medium).

Figure 3

Methods used for epidemiological studies of Y. enterocolitica-2. DNA colony hybridization assays [, –70]; PCR based detection methods [, –81]. (inv: gene for invasin, an outer membrane protein that is required for efficient translocation of bacteria across the intestinal epithelium; ail: gene for adhesin, an outer membrane protein that may contribute to adhesion, invasion and resistance to complement-mediated lysis; yst: gene for heat-stable enterotoxin that may contribute to the pathogenesis of diarrhea associated with acute yersiniosis; virF: gene for transcriptional activator; yadA, gene for Yersinia adhesin A; PFGE: pulsed field gel electrophoresis).