Department of Clinical Microbiology, Health Sciences Centre/Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada R3A 1R9.
J Antimicrob Chemother. 2013 May;68 Suppl 1:i47-55. doi: 10.1093/jac/dkt026.
To compare the demographics, antimicrobial susceptibilities and molecular epidemiology of community-associated (CA) and healthcare-associated (HA) methicillin-resistant Staphylococcus aureus (MRSA) in Canada.
Between 2007 and 2011, 1266 MRSA were collected from inpatients and outpatients attending tertiary-care medical centres across Canada. Susceptibility testing was performed using broth microdilution and isolates were characterized by spa typing and PCR to detect the Panton-Valentine leucocidin (PVL) gene. Detection of heterogeneous vancomycin-intermediate S. aureus (hVISA) was performed using the Etest macromethod and confirmed by population analysis profiling.
The annual proportion of S. aureus that were methicillin resistant decreased from 26.1% in 2007 to 19.3% in 2011 (P= 0.0002). Of 1266 MRSA isolated, 366 (28.9%) were CA-MRSA genotypes and 868 (68.6%) were HA-MRSA genotypes. The proportion of MRSA represented by CA-MRSA genotypes increased from 19.7% to 36.4% between 2007 and 2011 (P < 0.0001). CMRSA10 (USA300) was the predominant CA-MRSA genotype (22.1%); the most common HA-MRSA genotype was CMRSA2 (USA100/800) (58.1%). PVL was detected in 328/366 (89.6%) of CA-MRSA genotypes and 6/868 (0.7%) of HA-MRSA genotypes. The hVISA phenotype was detected in 7/27 (25.9%) of MRSA with a vancomycin MIC of 2 mg/L.
The most frequent CA-MRSA genotype was CMRSA10 (USA300), while CMRSA2 (USA100/800) was the predominant HA-MRSA genotype. Despite a decrease in the numbers of MRSA, the proportion of CMRSA10 (USA300) CA-MRSA has risen significantly between 2007 and 2011 in Canada.
比较加拿大社区获得性（CA）和医疗保健相关性（HA）耐甲氧西林金黄色葡萄球菌（MRSA）的人口统计学、抗菌药物敏感性和分子流行病学特征。
2007 年至 2011 年期间，从加拿大三级医疗中心的住院患者和门诊患者中收集了 1266 株 MRSA。使用肉汤微量稀释法进行药敏试验，通过 spa 分型和 PCR 检测葡萄球菌杀白细胞素（PVL）基因来对分离株进行特征分析。使用 Etest 宏法检测异质性万古霉素中介金黄色葡萄球菌（hVISA），并用群体分析轮廓法进行确认。
2007 年至 2011 年期间，金黄色葡萄球菌中耐甲氧西林的比例从 26.1%下降至 19.3%（P=0.0002）。在 1266 株分离的 MRSA 中，366 株（28.9%）为 CA-MRSA 基因型，868 株（68.6%）为 HA-MRSA 基因型。2007 年至 2011 年间，CA-MRSA 基因型代表的 MRSA 比例从 19.7%增加至 36.4%（P<0.0001）。CMRSA10（USA300）是最主要的 CA-MRSA 基因型（22.1%）；最常见的 HA-MRSA 基因型是 CMRSA2（USA100/800）（58.1%）。在 366 株 CA-MRSA 基因型中，328 株（89.6%）检测到 PVL，在 868 株 HA-MRSA 基因型中，6 株（0.7%）检测到 PVL。在 27 株万古霉素 MIC 值为 2mg/L 的 MRSA 中，检测到 7 株（25.9%）为 hVISA 表型。
最常见的 CA-MRSA 基因型是 CMRSA10（USA300），而 CMRSA2（USA100/800）是最主要的 HA-MRSA 基因型。尽管 MRSA 的数量有所减少，但在 2007 年至 2011 年间，加拿大 CA-MRSA 中 CMRSA10（USA300）的比例显著上升。
