The study to evaluate the prevalence of Yersinia species in salad sold and water supplied in Quetta city, Pakistan

The spectrum of foodborne illness has been changed dramatically because of modern life style. This pilot study was intended to investigate the contaminated salad and water with Yersinia species and to determine their antimicrobial susceptibility pattern in 200 collected samples. Typical biochemical tests along with advanced molecular techniques were adopted for characterization of the isolated bacteria. In salad sample 20% (n=100) were contaminated with Yersinia species when biochemical tests were adopted for identification, however polymerase chain reaction (PCR) test confirmed the contamination of 27% of the samples. Out of 100 water samples analyzed 6 and 8 were found contaminated as confirmed by biochemical and PCR respectively. PCR based species typing was performed on the Yersinia isolated from the analyzed samples. The PCR confirmed isolates were further investigated by multiplex PCR to identify the specific species involved. Multiplex PCR demonstrated that 34 were Yersinia enterocolitica and 5 were identified as Yersinia pseudotuberculosis. Further segregation of multiplex PCR outcomes demonstrated that salad samples were most contaminated with Y. enterocolitica (n=27) and only two water samples were found positive. Similarly, out of five Y. pseudotuberclosis isolated, 4 were detected in salad samples while only 1 water sample was found contaminated with Y. pseudotuberclosis. Importantly, no sample was found contaminated with Y. pestis. The isolated Yersinia species were susceptible to Gentamicin, Tobramycin, Chloramphinicol, Nalidixic acid, Levofloxacin, Ciprolopxicin, Imipenum, Ceftaxine, and Cefrixone but resistant against Ampicillin, Amoxicillin, Tetracycline and Fosfomycin.