肠球菌中抗生素抗性传递的研究

Studies on Transferable Drug Resistance of Enterococci

本文初步研究四环素（Tc），红霉素（Ery），盐酸二甲胺四环素（Mn），庆大霉素（Gm＞2000μg／ml）抗性在肠球菌中转移的机制。从病理材料中分离获得扬球菌EF-1只能通过平板接合法把Tc、Mn、Ery、Gm抗性传递给受体坚韧的肠球菌EFR，获得一株不含质粒带的接台子Tc-16，Tc-16，又能作为供体把Tc、Mn、Ery抗性传递给肠球菌FT137，表明Tc、Ery、Mn抗性基因是位于接合转座子上。EF-1也仅能通过平板接合法把Gm抗性传递给EFR或FT137，在获得的接合子中，有一株（G-1）对Gm抗性，而Tc敏感，含单条小质粒带，一株GT-1对Gm、Tc、Ery、Mn抗性，含相同的单条小质粒带，对这两株接合子作质粒消除实验，都获得对庆大敏感的（GT-1仍对Tc、Ery、Mn抗性）不含质粒带的菌株，这说明庆大霉素抗性基因位于该质粒上。EF-1所含的质粒都是非接合性质粒，平板法接合传递中所获得的接合子，大都含有EF-1的数目不等的质粒带，说明这些质粒是被接合转座子诱动传递的。

The authors studied the mechanism on transfer of tetracycline, Erythromycin, Minocycline hydrochloride, Gentamicin resistance among enterococci. Only by plate mating, a multi-resistant and multi-plasmid enterococcus EF-1 isolated from nosocomial infections can transfer resistance of Tc, Ery, and Mn to a E. durans EFR, including a plasmid-free tranconjugants Tc-16. As a donor, Tc-16 can transfer resistance of Tc, Ery and Mn to E. hirae FT137 by plate mating. Plasmid of EF-1 are all non-conjugative, tranconjugants from plate mating has differnt plasmids of EF-1. The results indicate that Gm resistance was mediated by plasmid (named pBY01) and conjugative transposon Tn705 is mobilizing agent of enterococca 1 plasmids.