2018-2022年北京市某区腹泻病例副溶血弧菌流行与分子分型特征

Prevalence and molecular characterization of Vibrio Parahaemolyticus in patients with diarrhea in one district in Beijing,2018—2022

目的分析2018—2022年北京某平原郊区腹泻病例中副溶血弧菌的流行状况和分子分型特征,为疾病暴发和病原检测提供参考。方法分析由副溶血性弧菌引起的腹泻病例流行病学及临床资料,对病例的分离菌株进行毒力基因检测和脉冲场凝胶电泳(pulsed field gel electrophoresis,PFGE)分子分型,利用致病菌识别网对PFGE图谱进行聚类分析。结果腹泻病例中副溶血弧菌检出率为6.83%(87/1273),不同年份和年龄组检出率差异有统计学意义(χ^(2)趋势=16.47,χ^(2)=0.005,P<0.01;病例主要临床症状为腹泻(98.85%,86/87)、恶心(87.36%,76/87)、腹痛(68.97%,60/87);分离菌株有11种血清型,构成比前3位为O3∶K6(58.62%,51/87)、O10∶K4(14.94%,13/87)和O4∶KUT(10.34%,9/87),O3∶K6血清型比例随年份下降,O10∶K4血清型比例随年份上升,差异有统计学意义(χ^(2)趋势=22.25、34.95,P<0.01);85株副溶血弧菌携带毒力基因特征为tdh+/trh-,2株为tdh+/trh+;87株菌共有37种PFGE带型,4种血清型(O3:K6、O10:K4、O4:KUT、O6:KUT)中均存在带型一致且检出时间接近的菌株。结论本地区腹泻病例副溶血弧菌流行强度下降,血清型分布多样且优势血清型发生转变,多种血清型可能存在分散暴发,应加强副溶血弧菌相关暴发监测和深度病原学监测。

Objective To analyze the prevalence and molecular characteristics of Vibrio parahaemolyticus in cases of diarrhea in a suburb district in the plain of Beijing,so as to provide reference for detection of disease outbreak and etiological testing.Methods Epidemiological and clinical data of the diarrhea cases caused by V.parahaemolyticus were collected.Virulence gene detection and molecular typing of pulsed field gel electrophoresis(PFGE)were conducted for the strains isolated from the cases.PFGE fingerprints of V.parahaemolyticus were processed with cluster analysis using Chinese Pathogen Identification Net.Results The detection rate of V.parahaemolyticus in diarrhea cases was 6.83%(87/1273),with a statistically significant difference in different years(χ^(2)t rend=16.47,P<0.01)and in different age groups(χ^(2)=0.005,P<0.01).The most common clinical symptom was diarrhea(98.85%,86/87),followed by nausea(87.36%,76/87)and abdominal pain(68.97%,60/87).Of the isolated strains,11 serotypes were identified,and the top three were O3:K6(58.62%,51/87),O10:K4(14.94%,13/87),and O4:KUT(10.34%,9/87).The proportion of O3:K6 serotype decreased and the proportion of O10:K4 serotype increased over the study period,both with a statistically significant difference(χ^(2)t rend=22.25,34.95,P<0.01).All the V.parahaemolyticus strains carried virulence gene tdh,only 2 strains carried virulence gene trh.Among the 87 strains,a total of 37 PFGE patterns were identified,and strains with the same PFGE pattern and close detection time were observed in 4 serotypes(O3:K6,O10:K4,O4:KUT,O6:KUT).Conclusions The epidemic intensity of V.parahaemolyticus in diarrhea cases in the study area has decreased.The serotypes of V.parahaemolyticus are diverse,and the dominant serotype has changed.There may be scattered outbreaks of various serotypes.It is necessary to strengthen the surveillance of outbreaks and in-depth etiological surveillance of V.parahaemolyticus.