Eliopoulos G M, Wennersten C, Zighelboim-Daum S, Reiszner E, Goldmann D, Moellering R C
Department of Medicine, New England Deaconess Hospital, Boston, Massachusetts.
Antimicrob Agents Chemother. 1988 Oct;32(10):1528-32. doi: 10.1128/AAC.32.10.1528.
During a 14-month period beginning in July 1986, three distinct clinical isolates of Streptococcus (Enterococcus) faecium demonstrating high-level resistance (MIC, greater than 2,000 micrograms/ml) to gentamicin, kanamycin, tobramycin, and streptomycin were recovered from individual patients at one institution. Combinations of ampicillin with any of these agents failed to show bactericidal synergism. By filter-mating techniques, high-level gentamicin resistance could be transferred into a susceptible recipient of the same species at frequencies as high as 1 x 10(-4); transfer into Streptococcus faecalis JH2-7 occurred at lower frequencies (less than 2 x 10(-7). Aminoglycoside substrate profile analysis of clinical isolates as well as of laboratory-derived cured strains and transconjugants revealed 2"-aminoglycoside phosphotransferase and 3'-aminoglycoside phosphotransferase (III) phosphorylating enzymes, AAC-6' acetylating activity above that attributable to the intrinsic activity characteristic of S. faecium, and a streptomycin adenylylating enzyme. All three isolates carried a 51-megadalton plasmid. Curing of this plasmid or conjugative transfer into susceptible recipients was associated with the loss or acquisition of high-level gentamicin resistance, respectively. Loss of high-level gentamicin resistance was also observed when curing techniques resulted in a decrease in the size of this plasmid equivalent to a 10-megadalton deletion. Transferable, high-level resistance to gentamicin and other aminoglycosides, which was previously recognized in S. faecalis, has now emerged in clinical isolates of S. faecium, with the attendant concerns for possible spread.
从1986年7月开始的14个月期间，在某一机构从不同患者身上分离出3株不同的粪肠球菌临床菌株，这些菌株对庆大霉素、卡那霉素、妥布霉素和链霉素表现出高水平耐药（最低抑菌浓度大于2000微克/毫升）。氨苄西林与上述任何一种药物联合使用均未显示出杀菌协同作用。通过滤膜接合技术，高水平庆大霉素耐药性能够以高达1×10⁻⁴的频率转移到同一物种的敏感受体中；转移到粪肠球菌JH2 - 7的频率较低（小于2×10⁻⁷）。对临床分离株以及实验室衍生的治愈菌株和接合子进行氨基糖苷类底物谱分析，发现了2'' - 氨基糖苷磷酸转移酶和3' - 氨基糖苷磷酸转移酶（III）磷酸化酶、高于粪肠球菌固有活性特征的AAC - 6'乙酰化活性以及一种链霉素腺苷酸化酶。所有三株分离株都携带一个51兆道尔顿的质粒。该质粒的消除或向敏感受体的接合转移分别与高水平庆大霉素耐药性的丧失或获得有关。当消除技术导致该质粒大小减少相当于10兆道尔顿的缺失时，也观察到了高水平庆大霉素耐药性的丧失。以前在粪肠球菌中发现的对庆大霉素和其他氨基糖苷类药物的可转移高水平耐药性，现已出现在粪肠球菌的临床分离株中，随之而来的是对其可能传播的担忧。
