Datta N, Dacey S, Hughes V, Knight S, Richards H, Williams G, Casewell M, Shannon K P
J Gen Microbiol. 1980 Jun;118(2):495-508. doi: 10.1099/00221287-118-2-495.
The incidence of trimethoprim resistance in enterobacteria causing infection in a London hospital increased from 5.6% in 1970 to 16% in 1979. The proportion of gentamicin-resistant aerobic Gram-negative bacilli had risen to 6.5% by 1979. During a 5-month period in 1977, during which no epidemic was recognized, all isolates resistant to either trimethoprim, gentamicin, tobramycin or amikacin were studied. The proportion of enterobacteria resistant to both trimethoprim and gentamicin (3.8% of the total) was significantly higher than expected assuming no correlation between acquisition of resistance characters. The resistance was transferable in 23% of trimethoprim-resistant and 76% of gentamicin-resistant strains. Trimethoprim resistance was carried by plasmids of seven different incompatibility groups and in at least four instances was part of a transposon. Gentamicin resistance was determined by plasmids of three groups - IncC, IncFII and IncW. Transposition of gentamicin resistance was not shown, though this may have been the means of evolution of the gentamicin R plasmids of InW, which determined aminoglycoside acetyltransferase, AAC(3). Some bacterial strains with their plasmids were endemic. There was evidence for these plasmids (i) acquiring new resistance genes by transposition, (ii) losing resistance genes by deletion and (iii) being transferred between bacterial species in the hospital.
在伦敦一家医院引起感染的肠道细菌中，甲氧苄啶耐药率从1970年的5.6%上升至1979年的16%。到1979年，耐庆大霉素的需氧革兰氏阴性杆菌比例已升至6.5%。在1977年的5个月期间，当时未发现有疫情，对所有对甲氧苄啶、庆大霉素、妥布霉素或阿米卡星耐药的分离株进行了研究。对甲氧苄啶和庆大霉素均耐药的肠道细菌比例（占总数的3.8%）显著高于假设耐药性状获得之间无相关性时的预期比例。23%的耐甲氧苄啶菌株和76%的耐庆大霉素菌株的耐药性是可转移的。甲氧苄啶耐药性由七个不同不相容群的质粒携带，至少在四种情况下是转座子的一部分。庆大霉素耐药性由三组质粒决定——IncC、IncFII和IncW。未显示庆大霉素耐药性的转座情况，不过这可能是IncW的庆大霉素R质粒进化的方式，IncW质粒决定氨基糖苷乙酰转移酶AAC(3)。一些带有质粒的细菌菌株呈地方流行。有证据表明这些质粒：(i) 通过转座获得新的耐药基因；(ii) 通过缺失失去耐药基因；(iii) 在医院内不同细菌物种之间转移。
