Evaluation of Chromogenic Medium for Selective Isolation of Yersinia

摘要

代表的なエルシニアの選択分離培地として知られるCefsulodin-lrgasan-novobiocin寒天培地(CIN)〖よ，Yersinia enterocolitica血清型O3やYersinia pseudotuberculosisの一部の菌株の発育を阻害することが知られている.最近，新しいエルシニア選択培地，CHROM agar Yersima enterocolitica(CAYe)が開発されたので.その能力についてCINと比較検討を行った.Yersmia属菌株251株（病原性Y.enterocolitica 176株，Y.pseudotuberculosis 59株,および非病原性Yersiraia 16株）について，CINとCAYeでの発育を検討した.その結果，病原性Y.enterocolitica O3 104株中10株とY. pseudotuberculosis 59株以外の198菌株は，32℃ 48時間の培養で両培地に発育可能であった.いずれかの培地に発育できなかった病原性Y.enterocolitica O3 10株のうち，9株はサブリメント添加CINで，1株はサプリメント添加CAYeで発育できなかった.サプリメント添加CINに発育できなかった9株のうち，3株は，サプリメント非添加のCINでも発育できなかった.しかし，サプリメント添加CAYeで発育できなかった1株は，サプリメント非添加のCAYeでは発育可能であった.これらのことから，前者ではCINの培地成分が，後者ではCAYeのサプリメントが発育の阻害にかかわっているものと思われた.また，Y.pseudomわerculosis 59株は，サプリメント非添加のCAYeではすベて発育できた.CAYeは.コロニーの色で病原性Y.enterocoliticaを他の非病原性Yersinia属菌や他菌種から選択的に識別でき，CINと同等またはそれ以上の選択力があり，病原性Y.enterocoliticaの分離には適しているものと思われた.%Cefsulodin-irgasan-novobiocin agar (CIN) has been used as a selective agar to detect Yersinia in food or human patients; however, its components can inhibit the growth of some strains of Yersinia enterocolitica serovar 03 and Y. pseudotuberculosis. Recently, a new Yersinia selective agar, CHROMagar Yersinia enterocolitica (CAYe), was developed and evaluated as a novel selective agar for pathogenic Y. enterocolitica. In this research, a total of 251Yersinia strains (176 pathogenic Y. enterocolitica, 59 Y. pseudotuberculosis, and 16 non-pathogenic Yersinia) were cultured on both CIN and CAYe for comparison. Except for 10 of 104 pathogenic Y. enterocolitica 03 strains and 59 Y. pseudotuberculosis strains,198 Yersinia isolates grew on both media after 48 hr of incubation at 32℃.Of the 10 pathogenic Y. enterocolitica 03 which could not grow on CIN or CAYe, 9 strains could not grow on CIN with supplements and 1 strain could not grow CAYe with supplements. Of 9 strains which did not grow on CIN with supplements, 3 strains could not grow on CIN without supplements. However,1 strain which did not grow on CAYe with supplements could grow on CAYe without supplements. All of the Y. pseudotuberculosis strains could grow on CIN with/without supplements and on CAYe without supplements. The results indicate that the inhibition of the growth of Y. enterocolitica 03 on CIN is related to the components of CIN; however, the inhibition on CAYe appears to be related to the supplements in CAYe. Therefore, CAYe may be a more useful selective medium than CIN for pathogenic Y. enterocolitica .