一起水源性细菌性痢疾暴发疫情的病原学特征及溯源分析

目的 分析一起学校水源性细菌性痢疾暴发疫情中病例分离株之间及其环境分离株之间的病原学和分子分型特征及遗传相关性,追溯传染源。 方法 对疫情病例与外环境井水分离到的29株志贺菌进行分离鉴定、血清分型和药敏试验,通过脉冲场凝胶电泳(PFGE)获得电泳图谱,利用BioNumerics软件对图谱进行聚类分析,探讨菌株间的相关性。 结果 疫情病例和外环境井水中分离的29株志贺菌均为宋内Ⅰ相,29株志贺菌耐药结果显示产超广谱β-内酰胺酶菌株占96.55%。PFGE方法显示有3种脉冲场凝胶电泳图谱,相似率在72.8%~100%之间,井水中分离的2株志贺菌与疫情病例分离的25株菌株之间100%同源。 结论 结合实验室结果和流行病学调查,可以证实该事件是一起因饮用和使用宋内志贺菌污染的井水而导致的细菌性痢疾暴发疫情。

Pathogenic characteristics and traceability of a water-borne bacillary dysentery outbreak

Objective To trace the source of a waterborne bacterial dysentery form a school outbreak and to analyze the etiological characteristics and genetic correlation between the patient strains and the isolated environmental strains. Methods All the 29 Shigella bacteria strains isolated from patients and well water were subject to isolation and identification, serotyping and drug sensitive test. Electrophoresis patterns were obtained by pulsed field gel electrophoresis (PFGE), and then subject to cluster analysis by BioNumerics to study the correlation among the strains. Results All the 29 isolates were Shigella sonnei Phase Ⅰ, and 96.55% isolates produced extended spectrum β-lactamases. Three kinds of PFGE patterns were obtained, with similar rates between 72.8%-100%. The 25 isolates from patients and 2 from well water were 100% homologous. Conclusions Based on the laboratory Results and epidemiological investigation, it is a water-borne bacillary dysentery outbreak caused by drinking or using Shigella sonnei contaminated well water.