Assessment of Ail Gene Marker Amplicon for Mo­lecular Characterization of Pathogenic Yersinia enterocolitica in Food Samples Collected in Iran

Abstract

Background: To assess the utility of the chromosomal ail virulence gene sequence for detection of pathogenic Yersinia en­terocolitica in raw meet food products (beef, lamb, and chicken).

Methods: This study included 39 Yersinia enterocolitica positive cultures from suspicious food samples, in a working pe­riod of six months. These samples were referred to the "Food-Borne Diseases and Chronic Diarrhea Lab at Research Cen­tre for Gastric and Liver Diseases" of the Taleghani Hospital at Shahid Beheshti University of Medical Sciences, Te­hran, Iran. Isolates from 8 cultured Y. intermedia, Y. aldovi, Y. intermedia type O:45, Y. kristensenii, Y. enterocolitica type O:12/26, Y. enterocolitica type1/7/8, Y. frederiksenii type O:39, and Y. enterocolitica type O:8 samples were in­cluded in the study. Four non-Yersinia species Salmonella typhi, Shigella dysenteriae, Shigella flexeneri, and Proteus mirabi­lis were used for specificity testing. An established Yersinia type O:9 was used as positive control and for sensitiv­ity testing. An in-house real-time PCR assay was designed in order to rapidly and specifically identifies the pres­ence of specific Yersinia species.

Results: Out of 39 tested Y. enterocolitica samples, 6(2.3%) showed positive results for the ail gene PCR prod­uct, typed as O:8, and O:9, respectively. PCR products were sent for sequencing. Two sequences were registered with the Na­tional Center for Biotechnology Information (NCBI Genbank) as polymorphic ail gene sequences under the acces­sion numbers of DQ157767 and DQ003329.

Conclusions: Collectively, this test is well adapted for definite confirmation of pathogenic Y. en­terocolitica in food sam­ples.