Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, China.
Diagn Microbiol Infect Dis. 2012 Dec;74(4):363-8. doi: 10.1016/j.diagmicrobio.2012.08.015. Epub 2012 Sep 26.
A better understanding of virulence gene profiling and molecular characterization of Staphylococcus aureus isolates associated with bloodstream infection (BSI) may provide further insights related to clinical outcomes with these infections. We analyzed 89 S. aureus isolates including 37 MRSA isolates (41.6%) recovered from 89 adult patients with BSI from 4 hospitals in Zhejiang province, eastern China. Thirty-five (94.6%) of MRSA isolates and 4 (7.7%) of methicillin-sensitive S. aureus (MSSA) isolates were resistant to multiple antimicrobials. All isolates harbored at least 2 of 22 possible virulence genes, including sdrC (92.1%), icaA (89.9%), hla (80.9%), clf (69.7%), sea (68.5%), sdrD (67.4%), hlb (67.4%), sdrE (65.2%), sei (51.7%), seg (50.6%), and cna (50.6%). Forty-four (49.4%) of all S. aureus BSI isolates, including 23 (62.2%) of MRSA isolates, harbored ≥10 of the virulence genes evaluated in this study. Sixteen (43.2%) MRSA isolates and 5 (9.6%) MSSA isolates harbored the gene encoding Panton-Valentine leukocidin (PVL). Collective genes for pvl, sdrE, sed, seg, and sei among MRSA isolates were significantly more frequent relative to MSSA isolates (P < 0.05). A total of 22 sequence types (STs), including novel ST2184, ST2199, and ST2200, and 33 spa types, including novel spa types t9530 and t9532, were identified among S. aureus BSI isolates, among which ST188 (15.7%) and ST7 (15.7%), and t091 (12.4%) and t189 (12.4%), seldom noted for Chinese isolates previously, were major STs and spa types, respectively. In contrast to previous reports, no predominant clones were found in the present study. Among the MRSA isolates, although ST239-MRSA-SCCmecIII, predominant clone in China, still represented the most common clone, it only accounted for 18.9%. However, ST188-MRSA- SCCmecIV seldom reported before accounted for 10.8%. Among the MSSA isolates, ST7-MSSA represented the most common clone (23.1%), followed by ST188-MSSA and ST630-MSSA (9.6% each). In conclusion, simultaneous carriage of multiple virulence genes and genetically considerable diversity were common among S. aureus BSI isolates. Furthermore, MRSA isolates exhibited more frequent carriage of superantigen genes and pvl relative to MSSA isolates. Taken together, there are distinctive virulence gene profiling and molecular characteristic among S. aureus isolates associated with bloodstream infection in China.
更好地了解与血流感染（BSI）相关的金黄色葡萄球菌分离株的毒力基因谱和分子特征，可能有助于进一步了解这些感染的临床结果。我们分析了 89 株金黄色葡萄球菌分离株，包括来自中国东部浙江省 4 家医院的 89 名 BSI 成年患者的 37 株耐甲氧西林金黄色葡萄球菌（MRSA）分离株（41.6%）。35 株（94.6%）MRSA 分离株和 4 株（7.7%）甲氧西林敏感金黄色葡萄球菌（MSSA）分离株对多种抗菌药物耐药。所有分离株均携带至少 22 种可能的毒力基因中的 2 种，包括 sdrC（92.1%）、icaA（89.9%）、hla（80.9%）、clf（69.7%）、sea（68.5%）、sdrD（67.4%）、hlb（67.4%）、sdrE（65.2%）、sei（51.7%）、seg（50.6%）和 cna（50.6%）。44 株（49.4%）金黄色葡萄球菌 BSI 分离株（包括 23 株[62.2%]MRSA 分离株）携带本研究评估的至少 10 种毒力基因。16 株（43.2%）MRSA 分离株和 5 株（9.6%）MSSA 分离株携带编码杀白细胞素 Panton-Valentine（PVL）的基因。MRSA 分离株中与 PVL、sdrE、sed、seg 和 sei 相关的基因座明显比 MSSA 分离株更为常见（P<0.05）。在金黄色葡萄球菌 BSI 分离株中鉴定出 22 种序列型（STs），包括新的 ST2184、ST2199 和 ST2200，以及 33 种 spa 型，包括新的 spa 型 t9530 和 t9532，其中 ST188（15.7%）和 ST7（15.7%）以及 t091（12.4%）和 t189（12.4%）在中国分离株中很少见，分别是主要的 ST 和 spa 型。与以前的报告不同，本研究中未发现优势克隆。在 MRSA 分离株中，尽管 ST239-MRSA-SCCmecIII 是中国的主要克隆，但仍占 18.9%。然而，以前很少报道的 ST188-MRSA-SCCmecIV 占 10.8%。在 MSSA 分离株中，ST7-MSSA 是最常见的克隆（23.1%），其次是 ST188-MSSA 和 ST630-MSSA（9.6%）。总之，金黄色葡萄球菌 BSI 分离株普遍携带多种毒力基因，遗传多样性较大。此外，MRSA 分离株携带超抗原基因和 PVL 的频率高于 MSSA 分离株。综上所述，中国血流感染相关金黄色葡萄球菌分离株存在独特的毒力基因谱和分子特征。
