ARS | Publication request: Serotype, Antimicrobial Resistance Patterns, Genotype and Virulence Characteristics of Pathogenic Yersinia Enterocolitica Isolated from Swine Feces

Submitted to: Meeting Abstract
Publication Acceptance Date: February 5, 2004
Publication Date: August 1, 2004
Citation: Bhaduri, S., Wesley, I.V., Wallace, F.M., Richards, H., Draughon, A.F. 2004. Serotype, Antimicrobial Resistance Patterns, Genotype And Virulence Characteristics Of Pathogenic Yersinia Enterocolitica Isolated From Swine Feces. Meeting Abstract.

Technical Abstract: Swine are the only known animal reservoir of Yersinia enterocolitica (YE) pathogenic to humans. Since YE is a fecal organism of swine, the primary goal of this study was to evaluate the characteristics of YE from swine feces by serotype, antibiotic susceptibility, presence of virulence plasmid, expression of plasmid-associated virulence determinants, and by determination of the clonal distribution of isolates. A total of 2,793 swine fecal samples collected from September 2000 to March 2001 from 78 production sites in 15 major pork producing states across the United States Were tested for the presence of YE in pigs. YE were isolated using a combination of ITC medium for enrichment and CIN agar and were identified by fluorogenic 5' nuclease PCR targeting the chromosomal attachment invasion ail gene. Serotyping and antimicrobial susceptibility testing were performed. Isolates were tested for markers of virulence including carriage of a 70-kbp plasmid, colony morphology, low calcium response, Congo red uptake, crystal violet binding, autoagglutination, hydrophobicity, and presence of a cytotoxicity factor, YopE. Clonal distribution of the isolates was determined by PFGE. Experimentally, 107 ail-positive YE were isolated from the 2,793 samples. One isolate from each positive sample was characterized. The predominant serotype, O:3 (n=81/107), was evenly distributed among isolates from the 15 states. Serotype O:5 (n=26/107) was found in pigs from only three states. Regional and serotype specific differences were observed in antimicrobial susceptibility. All isolates contained the virulence plasmid and expressed virulence-associated phenotypic characteristics. PFGE showed that O:3 and O:5 isolates were highly clonal within a serotype regardless of state of origin. The serotypes, presence of the ail gene, virulence plasmid, and the expression of virulence determinants indicate that these isolates are potentially capable of causing food borne illness. The results from this study will aid in the design of future epidemiological investigations concerning on-farm prevalence of pathogenic YE. Additionally, the results confirmed that swine are a reservoir for pathogenic YE.