Isolation and characterization of Yersinia enterocolitica in Taipei

Of 187 food samples analyzed, 3(1.6%) displayed the presence of Yersinia enterocolitica. All of them were isolated from frozen food samples. Two strains were isolated from 21 sliced beef samples (9.5%), and were identified as serotype O5. One strain was isolated from 20 egg dumpling samples (5%), and was typed as serotype O9. No Y. enterocolitica was found in refrigerated food samples. In addition to serotypes O5 and O9, serotypes O3 and O8 were also identified for other local strains that were included in this study. Three different biotypes have been determined for these strains according to Wauter's schema. Most of the strains tested for their antimicrobial susceptibility were resistance to carbenicillin, ampicillin and cephalothin, and all were susceptible to aminoglycosides, tetracycline, nalidixic acid, chloramphenicol, and sulfamethoxazole-trimethoprim. Five out of 7 strains carried plasmids, but these plasmids may not code for drug resistance.