Sadowski P L, Peterson B C, Gerding D N, Cleary P P
Antimicrob Agents Chemother. 1979 Apr;15(4):616-24. doi: 10.1128/AAC.15.4.616.
Gentamicin resistance in Klebsiella pneumoniae involved in an outbreak at the Minneapolis Veterans Administration Hospital was due to a transmissible R plasmid. In addition to gentamicin, this plasmid conferred resistance to tobramycin, kanamycin, ampicillin, carbenicillin, cephalothin, chloramphenicol, and sulfathiazole. R plasmids which transferred this complex antibiogram were identified in several clinical isolates, including four different serotypes of K. pneumoniae, Escherichia coli, Enterobacter cloacae, and Proteus morganii. The covalently closed circular form of all R plasmids isolated had a sedimentation coefficient of 76S to 77S, corresponding to a molecular weight of 58 x 10(6). The possibility that a single R plasmid was responsible for the dissemination of multiple drug resistance among all of these different clinical strains was examined by characterizing the plasmids by using EcoRI restriction endonuclease. The same 15 fragments were obtained from each of the 10 plasmids analyzed. Their molecular weights ranged from 4 x 10(5) to 11 x 10(6). Thus, we conclude that each of the 10 plasmids present in the various clinical strains isolated from the hospital over a 7-month period originated from a common source and that R plasmid transfer was important in their spread.
明尼阿波利斯退伍军人管理局医院爆发的疫情中，肺炎克雷伯菌对庆大霉素的耐药性是由一种可传递的R质粒引起的。除庆大霉素外，该质粒还赋予对妥布霉素、卡那霉素、氨苄青霉素、羧苄青霉素、头孢噻吩、氯霉素和磺胺噻唑的耐药性。在几种临床分离株中鉴定出了携带这种复杂抗菌谱的R质粒，包括四种不同血清型的肺炎克雷伯菌、大肠杆菌、阴沟肠杆菌和摩根氏变形杆菌。所有分离出的R质粒的共价闭合环状形式的沉降系数为76S至77S，对应分子量为58×10⁶。通过使用EcoRI限制性内切酶对质粒进行特征分析，研究了单个R质粒是否导致了所有这些不同临床菌株中多重耐药性传播的可能性。从分析的10个质粒中的每一个都获得了相同的15个片段。它们的分子量范围从4×10⁵到11×10⁶。因此，我们得出结论，在7个月期间从医院分离出的各种临床菌株中存在的10个质粒中的每一个都起源于一个共同来源，并且R质粒转移在它们的传播中起重要作用。
