Hayden M K, Trenholme G M, Schultz J E, Sahm D F
Section of Infectious Diseases, Rush-Presbyterian-St. Luke's Medcal Center, Chicago, IL 60612.
J Infect Dis. 1993 May;167(5):1224-7. doi: 10.1093/infdis/167.5.1224.
Acquired vancomycin resistance in enterococci may be associated with teicoplanin susceptibility (VanB) or teicoplanin resistance (VanA). This paper characterizes the first instance of in vivo emergence of teicoplanin resistance in an Enterococcus faecium strain of VanB phenotype. Vancomycin-resistant (MIC, 256/512 micrograms/mL) E. faecium was isolated intermittently from a patient's blood over 4 months. The MIC of teicoplanin for the first 5 isolates was 1.0 micrograms/mL; it was 64 micrograms/mL for the final 2. Analysis of plasmid and chromosomal DNA revealed the isolates to be of clonal origin. Conjugal transfer of vancomycin resistance was not obtained. A vanB DNA probe hybridized with both teicoplanin-susceptible and resistant isolates, but a vanA probe failed to hybridize with any isolate. SDS-PAGE of membrane proteins from a teicoplanin-resistant isolate revealed constitutive production of a normally inducible 41-kDa protein. These findings challenge the ultimate utility of teicoplanin for treatment of infections caused by vancomycin-resistant enterococci.
肠球菌中获得性万古霉素耐药性可能与替考拉宁敏感性（VanB）或替考拉宁耐药性（VanA）有关。本文描述了第一例粪肠球菌VanB表型菌株体内出现替考拉宁耐药性的情况。在4个月的时间里，从一名患者血液中间歇性分离出耐万古霉素（MIC，256/512微克/毫升）的粪肠球菌。最初5株分离菌的替考拉宁MIC为1.0微克/毫升；最后2株为64微克/毫升。对质粒和染色体DNA的分析表明这些分离菌来源于克隆。未获得万古霉素耐药性的接合转移。vanB DNA探针与替考拉宁敏感和耐药的分离菌均杂交，但vanA探针未与任何分离菌杂交。对一株替考拉宁耐药分离菌的膜蛋白进行SDS-PAGE分析，结果显示一种通常可诱导的41 kDa蛋白呈组成型表达。这些发现对替考拉宁用于治疗耐万古霉素肠球菌引起的感染的最终效用提出了质疑。
