Tantulavanich S, Olexy V M, Prasad T R, Bird T J, Talanda-Fath C, Grieble H G, Farrand S K
J Med Microbiol. 1981 Nov;14(4):371-80. doi: 10.1099/00222615-14-4-371.
Of 3952 clinical isolates of Enterobacteriaceae, 246 exhibited resistance to at least carbenicillin, gentamicin and tobramycin. All these isolates, representing eight genera, were resistant to at least nine antimicrobial agents in common, including the three key antibiotics and streptomycin, kanamycin, sisomycin, ampicillin, cephalothin and sulphonamide. The strains could be subdivided into seven groups depending upon additional resistance traits and some were resistant to as many as 15 antibiotics. When mated with a standard strain of Escherichia coli, 85% of 123 randomly selected donors transferred resistance to at least the nine core antibiotics. Some donors occasionally transferred resistance to two additional antibiotics, neomycin and tetracycline, while one Citrobacter freundi donor always transferred linked resistance to all 11 drugs. Although many donors were found to harbour more than one species of plasmid DNA, all except a strain of C. freundi contained at least a plasmid of mol. wt 89 x 10(6). Analysis of E. coli transconjugants showed this plasmid to be responsible for transferable resistance to the nine core antibiotics. Restriction-endonuclease analysis indicates that the 89 x 10(6) plasmids originating from different isolates were essentially identical with each other. These results show that a particular R plasmid has established itself among the Enterobacteriaceae at Hines VA Hospital. This R plasmid appears to be the predominant genetic element responsible for linked resistance to carbenicillin, gentamicin and tobramycin among these hospital-associated bacteria.
在3952株肠杆菌科临床分离菌中，有246株至少对羧苄青霉素、庆大霉素和妥布霉素耐药。所有这些分离菌分属于8个菌属，它们共同对至少9种抗菌药物耐药，包括上述3种关键抗生素以及链霉素、卡那霉素、西索米星、氨苄青霉素、头孢噻吩和磺胺类药物。这些菌株可根据其他耐药特性再分为7组，有些菌株对多达15种抗生素耐药。当与标准大肠杆菌菌株接合时，123株随机挑选的供体菌株中有85%可将耐药性传递给至少9种核心抗生素。一些供体偶尔还会将对另外两种抗生素（新霉素和四环素）的耐药性传递给受体，而一株弗氏柠檬酸杆菌供体总是会将对所有11种药物的连锁耐药性传递给受体。虽然发现许多供体菌株含有不止一种质粒DNA，但除了一株弗氏柠檬酸杆菌外，所有菌株都至少含有一种分子量为89×10⁶的质粒。对大肠杆菌接合子的分析表明，这种质粒是导致对9种核心抗生素产生可传递耐药性的原因。限制性内切酶分析表明，源自不同分离菌的89×10⁶质粒彼此基本相同。这些结果表明，一种特定的R质粒已在海因斯退伍军人医院的肠杆菌科细菌中确立了自身地位。这种R质粒似乎是这些医院相关细菌中对羧苄青霉素、庆大霉素和妥布霉素产生连锁耐药性的主要遗传元件。
