Laboratory of Microbiology and Infection Control, University Hospital Antoine-Béclère, Assistance Publique-Hôpitaux de Paris, Paris Sud University, 92140 Clamart, France.
J Antimicrob Chemother. 2013 Aug;68(8):1714-7. doi: 10.1093/jac/dkt085. Epub 2013 Mar 27.
Mupirocin is the cornerstone of decolonization regimens, a successful strategy to prevent healthcare-associated staphylococcal infections. Several recent studies have reported alarming results: (i) an extending reservoir of mupA, the ancestral mobile resistance gene, among coagulase-negative staphylococci (CoNS); (ii) the emergence of a new resistance gene (mupB); and (iii) a growing number of mupirocin-resistant methicillin-resistant Staphylococcus aureus (MRSA), including highly pathogenic clones. We performed a nationwide prospective study in France to detect such trends among invasive staphylococci.
Between October 2011 and February 2012, 367 MRSA and 708 CoNS invasive isolates were collected from 37 hospitals and analysed centrally. Mupirocin MICs were determined using the broth microdilution method. mupA/B PCR was performed for resistant isolates (MIC >1 mg/L). Genetic relatedness between mupirocin-resistant MRSA isolates was determined by PFGE analysis and related isolates were tested by microarray.
Among MRSA isolates 2.2% (n = 8) were classified as mupirocin resistant; 1.4% (n = 5) showing low-level resistance (MIC ≤256 mg/L) and 0.8% (n = 3) high-level resistance (MIC >256 mg/L). Only the latter isolates carried mupA. A clonal relationship was identified between two mupA-negative MRSA from the same hospital and three mupA-positive MRSA from three distant towns; these three isolates belonged to the Lyon clone. Mupirocin resistance was identified in 10.3% of CoNS, mainly highly resistant mupA-positive isolates (5.6%). The mupB gene was not detected in mupirocin-resistant MRSA or CoNS.
This first large national study indicates the need for thorough epidemiological monitoring and a stewardship programme to prevent and detect mupirocin resistance in staphylococci.
莫匹罗星是去定植治疗方案的基石，也是预防医源性葡萄球菌感染的成功策略。最近的几项研究报告了令人震惊的结果：（i）凝固酶阴性葡萄球菌（CoNS）中移动耐药基因 mupA 的储备不断扩大；（ii）新耐药基因（mupB）的出现；以及（iii）越来越多的耐莫匹罗星的耐甲氧西林金黄色葡萄球菌（MRSA），包括高致病性克隆。我们在法国进行了一项全国性前瞻性研究，以检测侵袭性葡萄球菌中是否存在这些趋势。
2011 年 10 月至 2012 年 2 月，从 37 家医院收集了 367 株 MRSA 和 708 株 CoNS 侵袭性分离株，并进行了集中分析。使用肉汤微量稀释法测定莫匹罗星 MIC。对耐药分离株（MIC > 1 mg/L）进行 mupA/B PCR。通过 PFGE 分析确定耐莫匹罗星 MRSA 分离株之间的遗传相关性，并通过微阵列检测相关分离株。
在 MRSA 分离株中，2.2%（n = 8）被归类为莫匹罗星耐药；1.4%（n = 5）表现出低水平耐药（MIC ≤ 256 mg/L），0.8%（n = 3）表现出高水平耐药（MIC > 256 mg/L）。只有后者携带 mupA。来自同一医院的两个 mupA 阴性 MRSA 和来自三个不同城镇的三个 mupA 阳性 MRSA 之间存在克隆关系；这三个分离株属于里昂克隆。CoNS 中发现 10.3%的莫匹罗星耐药，主要是高度耐药的 mupA 阳性分离株（5.6%）。未在耐莫匹罗星的 MRSA 或 CoNS 中检测到 mupB 基因。
这项首次全国性大型研究表明，需要进行彻底的流行病学监测和管理计划，以预防和检测葡萄球菌中的莫匹罗星耐药性。
