2016与2019年成人致泻性大肠埃希菌食源性腹泻临床流行病学特征研究

Comparison of clinical epidemiological characteristics of adult diarrheal Escherichia coli food-borne diarrhea in 2016 and 2019

目的研究2016与2019年成人致泻性大肠埃希菌(DEC)食源性腹泻临床特征与耐药性,了解北京市强化食品卫生安全措施前后DEC流行病学变迁。方法分别收集2016和2019年就诊于北京同仁医院肠道门诊食源性成人腹泻患者1926例和1482例,共计3408例。患者信息录入“肠道预警系统”,便标本分离培养,菌落行基质辅助激光解析电离飞行时间质谱(MALDI-TOF)鉴定。大肠埃希菌采用多重荧光定量PCR对5种致病型进行分型。药物敏感性试验根据2019美国临床与实验室标准化协会标准判读。分类资料采用χ^(²)检验或者Fisher精确检验进行统计分析。结果3408份标本共检出DEC 581株,肠产毒性大肠埃希菌(ETEC)占53.36%(310/581),未检出肠出血性大肠埃希菌(EHEC)。2016年DEC检出率为14.54%(280/1926),肠聚集性大肠埃希菌(EAEC)占DEC检出率的18.21%(51/280),ETEC占71.79%(173/280)。2019年DEC检出率为20.31%(301/1482),EAEC占DEC检出率的41.23%(116/301),ETEC占48.93%(137/301)。与2016年比较,2019年EAEC检出率增高(χ^(²)=29.26,P<0.001),其次为肠致病性大肠埃希菌(χ^(²)=9.37,P=0.002),而ETEC检出率下降(χ^(²)=15.43,P<0.001)。与其他致病型相比,EAEC易引起恶心(χ^(²)=32.72,P<0.001),感染肠侵袭性大肠埃希菌(EIEC)的患者便标本易观察到红细胞(χ^(²)=16.44,P=0.001)和白细胞(χ^(²)=26.82,P<0.001)。EIEC对氨苄西林、氨苄西林/舒巴坦及庆大霉素耐药率分别为80.95%(17/21)、66.67%(14/21)和57.14%(12/21)。2019年出现3株耐碳青霉烯类抗菌药物的EAEC,其中2株厄他培南及亚胺培南均耐药,1株仅厄他培南耐药。全基因测序显示存在多种耐药机制,以耐药结节性细胞分化家族外排泵、青霉素结合位点突变及产新德里金属β内酰胺酶5(NDM-5)为主。结论成人食源性腹泻患者DEC检出率高,以ETEC为主。与2016年相比,2019年ETEC下降,EAEC检出率显著升高,并于2019年分离到耐碳青霉烯类抗菌药物的致泻性大肠埃希菌菌株,其生物学特征及流行病学变迁应引起临床重视。

Objective To quantitatively analyze the clinical and drug resistance feature of diarrhea of adults patients in 2016 and 2019 induced by the Escherichia coli(diarrheagenic Escherichia coli,DEC),and to reveal the difference of DEC′s epidemiological features of before and after measuring to strengthen food hygiene and safety in Beijing.Methods A total number of 3408 patients with food-borne adult diarrhea were received diagnosis and treatment in the intestinal clinic department of Beijing Tongren Hospital in 2016 and 2019.There were 1926 patients in 2016 and 1482 in 2019,respectively.The clinical information of patient were entered into the intestinal early warning system and were carefully preserved.The clinical specimens(the stool samples)were isolated and the DECs were identified by culturing.The colony of DECs was identified by matrix assisted laser desorption ionization-time of flight(MALDI-TOF)mass spectrometry.Five pathogenic types of Escherichia coli were classified by multiplex PCR methods.The drug-susceptibility test was performed according to the standards of the American Society for Clinical and Laboratory Standardization in 2019.The categorical data were analyzed byχ2 test or Fisher′s exact test to verify the statistical difference.Results A total number of 581 DECs strains were detected in 3408 specimens.Among the subtypes of E Coli,the Enterotoxigenic Escherichia coli(ETEC)accounted for 53.36%(310/581),and Enterohemorrhagic Escherichia coli(EHEC)was detected.In 2016,the total detection rate of DEC was 14.54%(280/1926),enteroaggregative Escherichia coli(EAEC)accounted for 18.21%(51/280),and ETEC accounted for 71.79%(173/280).In 2019,the total detection rate of DEC was 20.31%(301/1482),EAEC accounted for 41.23%(116/301),and ETEC accounted for 48.93%(137/301).Compared with 2016,the detection rate of EAEC in 2019 increased significantly(χ^(²)=29.26,P<0.001),followed by EPEC(χ^(²)=9.37,P=0.002),and ETEC decreased(χ^(²)=15.43,P<0.001).Compared with other pathogenic types,EAEC can easily cause nausea(χ^(²)=32.72,P<0.001).The red blood cells(χ^(²)=16.44,P=0.001)or the white blood cells(χ^(²)=26.82,P<0.001)could be easily observed in stool specimens of patients infected with enteroinvasive Escherichia coli(EIEC).The resistance rates of EIEC to ampicillin,ampicillin/sulbactam and gentamicin were 80.95%(17/21),66.67%(14/21)and 57.14%(12/21),respectively.Three strains of EAEC resistant to carbapenem antimicrobials were discovered in 2019 and of which two strains were resistant to ertapenem and imipenem,and the other one strain was only resistant to ertapenem.The whole genomic sequencing showed that there are multiple resistance mechanisms:including the mainly drug-resistant nodular cell differentiation family efflux pump,penicillin binding site mutation,and New Delhi metal-β-lactamase 5 production.Conclusions The detection rate of DECs in adult patients with food-borne diarrhea is high,and the foremost subtype of DECs is ETEC.Compared with 2016,the detection rates of ETEC in clinical specimens decreased in 2019,and the detection rate of EAEC increased significantly,respectively.In 2019,a carbapenem-resistant antibacterial drug-resistant Escherichia coli strain was isolated.It is of great significance to focus on the biological characteristics and epidemiological changes of DEC.