engleski

Prevalence, phenotypic and genetic characterization of Yersinia enterocolitica isolated from slaughtered pigs raised in different housing systems in Croatia

Background. Yersinia enterocolitica is one of the leading zoonotic bacterial pathogens in European Union, and pork is considered the most important source of infection for humans. Objective. The study aimed to determine Y. enterocolitica prevalence in tonsils of slaughtered pigs raised in different housing systems and in retail pork, and to compare their phenotypic and genetic characteristics. Materials and Methods. At the slaughter line, 234 tonsils were sampled from pigs originating from 26 farms, including three large integrated farms (N = 69), ten medium farms (N = 130) and thirteen family farms (N = 35). Additionally, 128 samples of retail portioned and minced pork were sampled. Isolation was performed by PSB and ITC broth, CIN and CHROMagarᵀᴹ, and identification by MALDI-TOF MS and RT-PCR. Strains (N = 85) were biotyped, serotyped, subjected to PFGE analysis and tested for antibiotic susceptibility. Results. The overall prevalence of pathogenic Y. enterocolitica in tonsils was 43.16%. In tonsils of pigs from integrated farms, the prevalence was 29%, in medium farms 51.5% and in family farms 40%. Y. enterocolitica was absent in retail pork. All presumptive colonies from CHROMagar® (pYV +) were confirmed as Y. enterocolitica by MALDI-TOF MS, possesed ail gene and belonged to bioserotype 4/O:3. PFGE typing revealed high genetic concordance (80.6 to 100%) of biotype 4/O:3 strains. Multi-resistant strains occurred more frequently in integrated farms (P<0.05), with dominant resistance to cephalothin and ampicillin, but also to nalidixic acid, chloramphenicol and streptomycin. Discussion and Conclusion. The study shows persistence of Y. enterocolitica bioserotype 4/O:3 in tonsils of pigs from different farming systems in Croatia, but the risk of pathogen transmission through the pork chain is low. Perspectives. This is the first study characterizing Y. enterocolitica in the pork production chain in Croatia and the basis for the introduction of serological surveillance.

Yersinia enterocolitica, pig, farm, tonsils, antimicrobial resistance

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