Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany.
Int J Antimicrob Agents. 2010 Feb;35(2):119-25. doi: 10.1016/j.ijantimicag.2009.10.012. Epub 2009 Dec 16.
Hospital-adapted Enterococcus faecium differ from their colonising variants in humans and animals by additional genomic content. Molecular typing based on multilocus sequence typing (MLST) allows allocation of isolates to specific clonal complexes (CCs), such as CC17 for hospital-adapted strains. Acquired ampicillin resistance is a specific feature of these hospital isolates, especially in Europe. A few recent reports have described acquired high-level ciprofloxacin resistance as a supposed feature of hospital-adapted E. faecium strains. In the present retrospective analysis, ciprofloxacin minimum inhibitory concentrations (MICs) of 609 clinical isolates from German hospital patients (1997-2007) were determined and a breakpoint for high-level resistance was deduced (>16mg/L). Acquired high-level ciprofloxacin resistance was distributed among isolates of 26 different MLST types (all CC17), indicating a wide prevalence of this acquired resistance trait among the hospital-adapted E. faecium population. High-level ciprofloxacin resistance was linked to gyrA and parC mutations in 98 investigated isolates. Eleven different allele types or combinations thereof were identified. Their allocation to specific MLST and pulsed-field gel electrophoresis (PFGE) types revealed differences in the emergence and spread of corresponding mutations and strains.
医院适应型屎肠球菌与人类和动物中的定植变体不同，其具有额外的基因组内容。基于多位点序列分型（MLST）的分子分型可将分离株分配到特定的克隆复合体（CC），例如医院适应型菌株的 CC17。获得性氨苄青霉素耐药性是这些医院分离株的一个特定特征，尤其是在欧洲。最近的一些报告描述了获得性高水平环丙沙星耐药性，这被认为是医院适应型屎肠球菌菌株的一个特征。在本回顾性分析中，测定了来自德国医院患者（1997-2007 年）的 609 株临床分离株的环丙沙星最小抑菌浓度（MIC），并推断出高水平耐药的断点（>16mg/L）。获得性高水平环丙沙星耐药性分布在 26 种不同 MLST 型（均为 CC17）的分离株中，表明这种获得性耐药特性在医院适应型屎肠球菌群体中广泛存在。在 98 株受检的分离株中，高水平环丙沙星耐药性与 gyrA 和 parC 突变有关。鉴定出 11 种不同的等位基因类型或其组合。将它们分配到特定的 MLST 和脉冲场凝胶电泳（PFGE）类型揭示了相应突变体和菌株的出现和传播的差异。
