2020年郑州某哨点医院儿童致泻性大肠埃希菌流行特征及分子分型分析

Epidemic characteristics and molecular typing of diarrheagenic Escherichia coli from children in a sentinel hospital in Zhengzhou, 2020

目的了解郑州市某哨点医院儿童致泻性大肠埃希菌(diarrheagenic Escherichia coli, DEC)的流行特征及分子分型特征,为今后本地区科学防控儿童DEC感染提供依据。方法对2020年收集的230份腹泻儿童和187份非腹泻儿童粪便标本进行常规细菌培养,采用多重PCR技术检测DEC的毒力基因和脉冲场凝胶电泳(pulsed field gel electrophoresis, PFGE)技术进行分子分型。结果 DEC在腹泻儿童与非腹泻儿童中的检出率分别为8.26%(19/230)和14.97%(28/187),腹泻儿童中检出的型别及检出率分别为典型黏附性大肠埃希菌(typical enteroaggregative Escherichia coli, tEAEC)(3.48%)、肠致病性大肠埃希菌(enteropathogenic Escherichia coli, EPEC)(2.61%)、非典型黏附性大肠埃希菌(atypical enteroaggregative Escherichia coli,aEAEC)(2.17%)和肠侵入性大肠埃希菌(enteroinvasive Escherichia coli, EIEC)(0.43%),非腹泻儿童中检出的型别为aEAEC(8.02%)、tEAEC(4.28%)、EPEC(3.74%)和产肠毒素大肠埃希菌(enterotoxigenic Escherichia coli, ETEC)(0.53%)。在腹泻儿童中黏液便的检出率高于稀便的检出率(χ;=47.332,P<0.001),在不同性别、不同年龄段中检出率无显著性差异。46株DEC分为44个带型,种内最高相似度为100.00%,最低相似度为24.54%,腹泻儿童与非腹泻儿童之间并未检测出带型一致的条带。结论 DEC在郑州市腹泻儿童与非腹泻儿童中优势型别是tEAEC、aEAEC和EPEC,提示DEC为机会致病菌。常见DEC型别的PFGE指纹图谱呈高度多态性,腹泻儿童与非腹泻儿童未发现同源克隆菌株的感染。

Objective To investigate the epidemic features and molecular typing of diarrheagenic Escherichia coli(DEC) from children in a sentinel hospital in Zhengzhou City, and to provide a basis for scientific prevention and control of DEC infection in children in future. Methods We collected 230 stool samples of diarrhea children and 187 stool samples of non-diarrhea children for routine bacterial culture in 2020. The virulence genes of DEC were detected by multiplex PCR, and pulsed field gel electrophoresis(PFGE) was used for molecular typing. Results The detection rates of DEC in the diarrhea and non-diarrhea children were 8.26%(19/230) and 14.97%(28/187), respectively. The most common pathogen in the diarrhea children was typical enteroaggregative Escherichia coli(tEAEC)(3.48%), followed by enteropathogenic Escherichia coli(EPEC)(2.61%), atypical enteroaggregative Escherichia coli(aEAEC)(2.17%) and enteroinvasive Escherichia coli(EIEC)(0.43%). The most common pathogen in the non-diarrhea children was aEAEC(8.02%), followed by tEAEC(4.28%), EPEC(3.74%) and ETEC(0.53%). Among the diarrhea children, the detection rate of DEC from mucus stool was higher than that from loose stool(χ;=47.332, P<0.001), and no statistically significant difference was found in the detection rate in different genders and different age groups. 46 strains of DEC were divided into 44 bands, with the highest similarity of 100% and the lowest similarity of 24.54%. No consistent bands were detected between the diarrhea children and the non-diarrhea children. Conclusion The dominant types of DEC in the diarrhea and non-diarrhea children in Zhengzhou City were tEAEC, aEAEC and EPEC, suggesting that DEC was an opportunistic pathogen. PFGE of the common types of DEC showed highly polymorphic,and no homologous clones were found between the diarrhea and non-diarrhea children.