Section of Infectious Diseases, Department of Pediatrics, The University of Chicago, 5841 S. Maryland Ave., MC 6054, Chicago, IL 60637, USA.
J Clin Microbiol. 2011 Jan;49(1):95-100. doi: 10.1128/JCM.00759-10. Epub 2010 Nov 17.
Mupirocin is a topical antimicrobial used to eradicate methicillin-resistant Staphylococcus aureus (MRSA) colonization, usually in the absence of susceptibility testing. We hypothesized that high-level (HL) mupirocin resistance was associated with multidrug resistance (MDR). To this end, unique patient isolates identified at our institution during 2008 were stratified into those resistant to ≥ 3 non-β-lactam antimicrobial classes (MDR) and non-MDR MRSA. HL mupirocin resistance was screened by mupA PCR on all MDR isolates (n = 191) and a 20% random sample (n = 130) of non-MDR isolates; E-testing confirmed HL resistance. We found that among MDR isolates, 13 (6.8%) carried mupA, whereas none of the non-MDR isolates did (P = 0.001). Thus, although the overall prevalence of HL mupirocin resistance is low among MRSA isolates at our institution, an association exists between mupA carriage and MDR. Using genotyping and antimicrobial susceptibility profiling, we identified nine HL mupirocin-resistant clones. Whereas the majority of mupA-negative MDR isolates had a health care-associated MRSA (HA-MRSA) genotype (multilocus sequence type 5 [ST5] or SCCmec type II), the majority of mupA-positive MDR isolates had a community-associated MRSA (CA-MRSA) genotype (ST8 or SCCmec type IV). However, CA- and HA-MRSA genotypes were more evenly distributed among mupA-positive isolates compared to mupA-negative MDR isolates. Thus, in Chicago, mupA is circulating among both CA- and HA-MRSA backgrounds.
莫匹罗星是一种局部用抗菌药物，用于消除耐甲氧西林金黄色葡萄球菌（MRSA）定植，通常在没有药敏试验的情况下使用。我们假设高水平（HL）莫匹罗星耐药与多药耐药（MDR）有关。为此，我们对 2008 年在我院分离的独特患者分离株进行分层，分为对≥3 种非β-内酰胺类抗菌药物耐药（MDR）和非 MDR-MRSA。对所有 MDR 分离株（n=191）和非 MDR 分离株的 20%随机样本（n=130）进行 mupA PCR 筛选 HL 莫匹罗星耐药；E 试验确认 HL 耐药。我们发现，在 MDR 分离株中，有 13 株（6.8%）携带 mupA，而非 MDR 分离株无一株携带 mupA（P=0.001）。因此，尽管我院 MRSA 分离株 HL 莫匹罗星耐药的总体流行率较低，但 mupA 携带与 MDR 之间存在关联。通过基因分型和抗菌药物敏感性分析，我们鉴定了 9 个 HL 莫匹罗星耐药克隆。虽然大多数 mupA 阴性 MDR 分离株具有医疗保健相关 MRSA（HA-MRSA）基因型（多位点序列型 5 [ST5]或 SCCmec 型 II），但大多数 mupA 阳性 MDR 分离株具有社区相关 MRSA（CA-MRSA）基因型（ST8 或 SCCmec 型 IV）。然而，mupA 阳性分离株中 CA 和 HA-MRSA 基因型的分布更为均匀，而 mupA 阴性 MDR 分离株中则不然。因此，在芝加哥，mupA 同时在 CA 和 HA-MRSA 背景中传播。
