Fica Alberto, Fernández Jorge, Ebensperger Germán, Cona Erna, Galanti Andrea, Alonso Catalina, Ulloa María Teresa, Frola Ana María, Prat Soledad
Departamento de Medicina, Hospital Clínico Universidad de Chile, Av. Santos Dumont 999, Independencia, Santiago.
Rev Med Chil. 2003 Feb;131(2):145-54.
Group A Streptococcal (GAS) infections have increased in frequency and severity worldwide. During April 1996, a nosocomial outbreak associated to GAS infections affected seven patients admitted to a pediatric burn unit. The causative organism was likely disseminated from the source patient to another child in the emergency room before he was transferred to the burn unit. Patients developed burn infections or invasive disease. One of them died due to a toxic shock syndrome and 3 other lost their skin grafts. Perineal and nasal microbiological surveillance of 42 related health care workers identified only one of them as carrier of S pyogenes.
To report a molecular analysis of an apparently clonal outbreak.
The available isolates were analyzed by molecular methods including random amplified polymorphic DNA analysis (RAPD) with 4 different primers, Sma-I pulsed field gel electrophoresis (PFGE) analysis, and speA, speB and speC detection by polymerase chain reaction (PCR).
Two phylogenetically distant and sequentially isolated bacterial groups were identified either by RAPD analysis with selected primers or by Smal-PFGE analysis. The first group involved isolates identified in two patients that included the lethal case. The second bacterial group comprised 5 clinical isolates and the perineal and nasal isolates obtained from a health care worker. Only strains belonging to the first group harbored the speA gene and were associated with invasive disease. The second group could be split further in two subgroups according to their speB profile.
RAPD analysis with selected primers can reproduce the PFGE-discriminating ability on the epidemiological analysis of GAS infections.
A 组链球菌（GAS）感染在全球范围内的发生频率和严重程度均有所增加。1996 年 4 月，一家儿科烧伤病房发生了一起与 GAS 感染相关的医院感染暴发，影响了 7 名入院患者。致病微生物可能在源患者被转至烧伤病房之前，就在急诊室从源患者传播给了另一名儿童。患者出现了烧伤感染或侵袭性疾病。其中 1 例因中毒性休克综合征死亡，另外 3 例皮肤移植失败。对 42 名相关医护人员进行的会阴和鼻腔微生物学监测仅发现其中 1 人为化脓性链球菌携带者。
报告对一次明显的克隆性暴发进行的分子分析。
采用分子方法对可用分离株进行分析，包括使用 4 种不同引物的随机扩增多态性 DNA 分析（RAPD）、Sma - I 脉冲场凝胶电泳（PFGE）分析以及通过聚合酶链反应（PCR）检测 speA、speB 和 speC。
通过使用选定引物的 RAPD 分析或 Smal - PFGE 分析，鉴定出两个系统发育距离较远且相继分离的细菌群。第一组包括在两名患者中鉴定出的分离株，其中包括致死病例。第二组细菌包括 5 株临床分离株以及从一名医护人员处获得的会阴和鼻腔分离株。只有属于第一组的菌株携带 speA 基因并与侵袭性疾病相关。根据 speB 谱型，第二组可进一步分为两个亚组。
使用选定引物的 RAPD 分析在 GAS 感染的流行病学分析中能够重现 PFGE 的鉴别能力。
