Yersinia enterocolitica의 신속증균법

Rapid enrichment method of yersinia enterocolitica

A KOH postenrichment treat procedure have been used for isolation of Yersinia spp., such conventional method was compare to KOH anteenrichment treatment procedure designated in this study for recovering of Y. entercolitica from feces inoculated with Y. enterocolitica and coliforms. The stool samples were homogenized in physicalsaline and autoclaved. Escherichia coli, Enterobacter aerogenes, and Klebsiella pneumoniae were each added to the suspension at a final concentration of 3×10⁴ per ml, Y. enterocolitica were then added to a final concentration 3×10, 3×10², 3×10³ or 3×10⁴ cells per ml. For KOH postenrichment treatment, 1 ml of feces suspension was tranferred into 9 ml of MacConkey broth and incubated for 48 hours at 25℃. Thereafter the suspension was treated with 0.25% KOH for 2 min. Also for KOH anteenrichment treatment, after feces suspension was treated with 0.15% KOH for 30 min.(before enrichiment), 1ml of the suspension transferred into 9 ml of MacConkey broth and then incubated for 24 hours at 21℃. Y. enterocolitica in feces suspension contaminated with more than 10³ cells per ml were equally recovered by using KOH postenrichment treatment or KOH anteenrichment treatment, but in suspensions contaminated with less than 10² cells per ml, KOH anteenrichment treatment proved to be more valuable procedure than KOH postenrichment treatment. The growth rate of Y. enterocolita inoculated in MacConkey broth contain ing 0.05% KOH was very superior to E. coli, E. aerogenes or K. pneumonia after incubation for 24 hours at 21℃.