Prevalence of Yersinia enterocolitica in Fattening Pigs

Abstract

The prevalence of pathogenic Yersinia enterocolitica in pig herds was monitored during six trials (at four different farrow-to-finisher farms). Samples were taken throughout the whole rearing period from birth of the piglets to the final fattening stage, and different samples were taken from these pigs during the slaughter process. Environmental samples also were evaluated to identify potential sources of on-farm infection. Y. enterocolitica was isolated using irgasan-ticarcillin-potassium chlorate broth enrichment and cefsulodin-irgasan-novobiocin agar culture. Colonies were identified using bio- and serotyping methods and by PCR assay. Pathogenic Y. enterocolitica were not isolated from fecal samples from piglets and weaners. The only fecal samples positive for Y. enterocolitica were obtained during the fattening stage. The prevalence of Y. enterocolitica in fattening pig herds ranged between 0 and 65.4%. Y. enterocolitica isolates were detected at the abattoir in 38.4% of the tonsils, in 3.8% of the ileocecal lymph nodes, on 0.3% of the carcass surfaces before chilling, and on 0% of the carcass surfaces after chilling. Almost all isolates belonged to bioserotype 4/O:3. Only one strain was identified as O:9. All isolates contained the ail gene. The yopT gene was found in 99.1% of the farm isolates but in only 76.6% of the isolates found at the abattoir from the corresponding carcasses. Although a direct link between porcine isolates and human infection has not been demonstrated, the similarity of the bioserotypes in infected pigs and humans and the presence of virulence factors in porcine isolates should encourage further studies to determine the risk of transmission of Y. enterocolitica to humans from pigs and pork products.

Essential Role of Invasin for Colonization and Persistence of Yersinia enterocolitica in Its Natural Reservoir Host, the Pig

“…In contrast, only the tonsils were efficiently colonized by O:8 in some of the infected minipigs. These results are in agreement with previous observations in surveys that reported that mainly serotype O:3 strains were isolated from the oral cavity, intestinal tract, and feces of pigs (21,38,39). Young pigs generally get infected within the first 3 weeks after entering contaminated areas (e.g., pens) or by other infected pigs, and they remain intestinal and pharyngeal carriers for long time periods (38).…”

Piglets Are a Source of Pathogenic Yersinia enterocolitica on Fattening-Pig Farms

“…An increase in the prevalence in feces up until 16 weeks of age of the pigs was noted, which was followed by a decrease over time until the end of the follow-up. This pattern is in agreement with previous studies (11,14,25). Despite the low fecal prevalence at the end of the period, most of the sampled pigs were seropositive at the time of slaughter.…”

Technical specifications for harmonised national surveys onYersinia enterocoliticain slaughter pigs

“…In the study of Nesbakken et al (2003), the proportion of pathogenic Yersiniae detected in tonsils compared to faeces was six to one. These proportions are similar to findings by Frederiksson-Ahomaa et al (2007) and Gürtler et al (2005), who reported that the frequency of isolated pathogenic Yersiniae was significantly greater from tonsils than that obtained from faeces at slaughter. In conclusion, when the pigs are slaughtered at the age of 135 days or more, the tonsils are a more significant source of human pathogenic Y. enterocolitica than faeces (Nesbakken et al, 2006).…”