金黄色葡萄球菌引起的皮肤和软组织感染（SSTIs）分离株的分子特征。
Molecular characterization of Staphylococcus aureus isolates causing skin and soft tissue infections (SSTIs).
机构信息
Department of Respiratory Medicine, the First Affiliated Hospital of Wenzhou Medical College, Wenzhou325000, China.
出版信息
BMC Infect Dis. 2010 May 26;10:133. doi: 10.1186/1471-2334-10-133.
BACKGROUND
Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), is an important cause of pyogenic skin and soft tissue infections (SSTIs). The aim of present study is to investigate the molecular characteristic of Staphylococcus aureus isolates isolated from the pus samples from the patients with purulent skin and soft tissue infections in Wenzhou, China.
METHODS
Between December 2002 and June 2008, a total of 111 nonduplicate S. aureus isolates were collected from the pus samples of the patients with SSTIs in a teaching hospital in Wenzhou, China. All the tested isolates were confirmed as S. aureus using a Staph SPA agglutination kit, Gram's stain and a Vitek-60 microbiology analyzer. The homology among the tested isolates was determined by pulsed-field gel electrophoresis (PFGE). Multilocus sequence typing (MLST) was used to determine the sequence types (STs) of the selected isolates. The genotypes of SCCmec were determined by a multiplex PCR in the MRSA isolates. Panton-Valentine leukocidin (PVL) genes and mecA were also determined by another multiplex PCR.
RESULTS
Among the 111 S. aureus isolates, 48 and 63 isolates were community-acquired and hospital-acquired respectively. Sixty isolates were confirmed as MRSA harboring mecA detected by PCR. A total of 32 PFGE clonal types were obtained by PFGE, with 10 predominant patterns (types A to J). Twenty-five different STs including ST398 and three novel STs were found among 51 selected isolates. The main STs were ST239, ST1018, ST59, ST7 and ST88. Of 60 MRSA isolates, SCCmec II, III, IV and SCCmec V were found in three, 50, three and two isolates, respectively. The positive rates of PVL genes in overall isolates, HA-isolates, CA-isolates, MRSA isolates and MSSA isolates were 23.4% (26/111), 20.6% (13/63), 27.1% (13/48), 21.7% (13/60) and 25.5% (13/51), respectively. Eight (33.3%, 8/24) of 24 CA-MRSA isolates and 5 (13.9%, 5/36) of 36 HA-MRSA isolates were positive for PVL genes. ST239-MRSA-SCCmecIII and ST1018-MRSA-SCCmecIII clones were found to be main clones and spread between community and hospital.
CONCLUSION
S. aureus isolates causing SSTIs showed considerable molecular heterogeneity and harbored high prevalence of PVL genes. Clonal spread was responsible for the dissemination of the isolates of S. aureus associated with SSTIs.
背景
金黄色葡萄球菌，尤其是耐甲氧西林金黄色葡萄球菌（MRSA），是化脓性皮肤和软组织感染（SSTIs）的重要原因。本研究的目的是研究从中国温州化脓性皮肤和软组织感染患者的脓液样本中分离出的金黄色葡萄球菌分离株的分子特征。
方法
2002 年 12 月至 2008 年 6 月，从中国温州一家教学医院的 SSTIs 患者的脓液样本中收集了总共 111 个非重复的金黄色葡萄球菌分离株。所有测试的分离株均通过葡萄球菌 SPA 凝集试剂盒、革兰氏染色和 Vitek-60 微生物分析仪确认为金黄色葡萄球菌。通过脉冲场凝胶电泳（PFGE）确定了测试分离株之间的同源性。多位点序列分型（MLST）用于确定选定分离株的序列类型（ST）。通过 MRSA 分离株中的多重 PCR 确定 SCCmec 型。通过另一个多重 PCR 也确定了杀白细胞素（PVL）基因和 mecA。
结果
在 111 株金黄色葡萄球菌分离株中，48 株为社区获得性，63 株为医院获得性。60 株通过 PCR 确认为携带 mecA 的 MRSA。通过 PFGE 获得了 32 个 PFGE 克隆型，其中有 10 种主要模式（类型 A 至 J）。在 51 株选定的分离株中发现了 25 种不同的 ST，包括 ST398 和三种新型 ST。主要 ST 为 ST239、ST1018、ST59、ST7 和 ST88。在 60 株 MRSA 分离株中，在 3 株、50 株、3 株和 2 株分离株中分别发现了 SCCmec II、III、IV 和 SCCmec V。总体分离株、HA 分离株、CA 分离株、MRSA 分离株和 MSSA 分离株中 PVL 基因的阳性率分别为 23.4%（26/111）、20.6%（13/63）、27.1%（13/48）、21.7%（13/60）和 25.5%（13/51）。24 株 CA-MRSA 分离株中有 8 株（33.3%，8/24）和 36 株 HA-MRSA 分离株中有 5 株（13.9%，5/36）为 PVL 基因阳性。发现 ST239-MRSA-SCCmecIII 和 ST1018-MRSA-SCCmecIII 克隆是主要的克隆，在社区和医院之间传播。
结论
引起 SSTIs 的金黄色葡萄球菌分离株表现出相当大的分子异质性，并具有高流行的 PVL 基因。克隆传播是与 SSTIs 相关的金黄色葡萄球菌分离株传播的原因。
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