Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/6/2006
Publication Date: 7/1/2006
Citation: Bhaduri, S., Wesley, I.V. 2006 Isolation and characterization of yersinia enterocolitica from swine feces recovered during the National Animal Health Monitoring System Swine 2000 Study. Journal of Food Protection. Vol.69:1552-1560. Interpretive Summary: Yersinia enterocolitica is a bacterium that is a common cause of food-borne illness in humans. Swine are the only known reservoir for the disease-causing (pathogenic ) Y. enterocolitica, and this bacterium is a serious concern of the pork production and processing industry in the United States. A national study, the National Animal Health Monitoring System (NAHMS) Swine 2000, on the national occurrence of pathogenic Y. enterocolitica in swine in the United States was facilitated by the United states Department of Agriculture (USDA), and the Animal and Plant Health Inspection Service (APHIS) in collaboration with the USDA-Agricultural Research Service (ARS). A combination of culture and polymerase chain reaction (PCR) was used to detect/isolate Y. enterocolitica in pig feces. Genetic virulence markers were used to determine the pathogenic potential of these Y. enterocolitica isolates. The expression of these virulence specific genetic markers showed that these isolates are potentially capable of causing food borne illness. The results of the study indicate that swine in the United States harbor pathogenic Y. enterocolitica and are a potential reservoir for strains that cause human illness. Since pork safety begins on the farm, pork producers play a critical role in providing safe pork products for the United States and international consumers. The data collected in the NAHMS Swine 2000 study will provide information to the pork industry on the prevalence and epidemiology of this pathogen and associated risk factors.
Technical Abstract: A national study was conducted for the isolation of pathogenic Yersinia enterocolitica in pig feces in the United States as part of the National Animal Health Monitoring System's Swine 2000 study. Fecal samples collected from swine operations from September 2000 to March 2001 from 77 production sites in 15 of the top 17 swine-producing states were tested for the presence of pathogenic Y. enterocolitica. After enrichment of swine fecal samples in Irgasan-ticarcillin potassium chlorate broth, the enriched cultures were plated on Cefsulodin-Irgasan-Novobiocin agar for isolation of presumptive Y. enterocolitica. The isolates were confirmed as pathogenic Y. enterocolitica by the fluorogenic 5' nuclease PCR assay targeting the chromosomal attachment invasion ail gene. Of 2.793 fecal samples tested, 106 (3.80%) ail-positive strains of Y. enterocolitica were isolated. These 106 ail-positive isolatets originated from 7 of the 15 participating states. The predominant serotype 0:3 (n = 79 of 106) was distributed in five states (n = 5 of 7). Serotype 0:5 (n - 27 of 106) was also found in five states (n = 5 of 7). All isolates contained the virulence plasmid and expressed virulence associated phenotypic characteristics. These results indicate that swine in the United States harbor Y. enterocolitica that can potentially cause human illness.