Et ve süt ürünlerinden yersinia türlerinin izolasyonu, fenotipik ve genotipik yöntemlerle adlandırılması ve bazı patojenite özelliklerinin belirlenmesi

The genus Yersinia belongs to the family Enterobacteriaceae and comprises 11 species, of which Y. enterocolitica and Y. pseudotuberculosis are well-known enteropathogens in humans and transmitted through contaminated food or water. In the present study, a total of 300 meat and milk products were collected and analyzed to determine the presence of Yersinia spp. Out of the 300 samples, 84 (28%) were positive for Yersinia spp. Eighteen (6%) out of 84 were identified to be Y. enterocolitica. The other Yersinia species were Y. rohdei 15 (5%), Y. intermedia 14 (4.7%), Y. pseudotuberculosis 12 (4%), Y. ruckeri 12 (4%), Y. mollaretii 5 (1.7%) and Y. bercovieri 4 (1.3%). Furthermore, 4 (1.3%) atypical Yersinia isolates were confirmed as Yersinia but could not be identified at Yersinia species level. The conventionally identified Y. enterocolitica strains were also confirmed by 16S rRNA amplification and sequencing. The prevalence of Yersinia spp. was 40.8% in meat products and 19.4% in milk products. Yersinia spp. was most frequently found in meat products at a rate of 51.7% in chicken meat and 30% in minced meat. Y. enterocolitica was the most common species in this research that was most frequently found in chicken meat. All Y. enterocolitica strains were tested for biotype profiles and phenotypic virulence characteristics including autoagglutination, Congo-red absorption and crystal-violet binding. In this study, as a result of phenotypic virulence tests, it was seen that none of the Y. enterocolitica biotyped as 1A had pathogenic potentials. Eighteen Y. enterocolitica and the other 66 Yersinia strains were genotypically examined for the presence of chromosomal (ail, ystA and ystB) and plasmid-encoded (yadA and virF) virulence genes. This study demonstrated that neither the Y. enterocolitica nor the other Yersinia strains harboured the ail, ystA, yadA, and virF genes. Only one strain of Y. intermedia and two strains of Y. enterocolitica had ystB. All 84 (100%) Yersinia spp. had resistance to clindamycin. Most Yersinia spp., namely, 86.9% were resistant to cephalothine, 78.6% to cephazoline, 64.3% to ampicillin and 57.1% to amoxicillin. A multidrug-resistance was observed in 71 (84.5%) of the strains to at least three or more antimicrobial agents. The present study is noteworthy in that it documents prevalence, virulence characteristics and antimicrobial resistance of Yersinia spp. and especially Y. enterocolitica as foodborne pathogen in meat and milk products. Thus, it is essential that these foods should be closely monitored for sanitation during all the processes from production till consumption and that their quality should be improved.