北京市通州区致泻性大肠埃希菌病原特征分析

Pathogenic characteristics analysis of diarrhea-causing Escherichia coli in Tongzhou District,Beijing

目的了解北京市通州区2016年-2019年腹泻患者致泻性大肠埃希菌病原学特征和耐药情况。方法对通州区2016年-2019年门诊腹泻监测病例的粪便标本进行致泻性大肠埃希菌的分离培养,利用荧光PCR方法进行菌株毒力基因检测,应用MIC法进行耐药试验。结果2016年-2019年通州区DEC菌株检出率为13.05%(217/1663),检出率逐年增高。20岁~39岁年龄组DEC检出率最高,其次为0岁~5岁组和≥60岁组。EAEC为主要型别,其次为ETEC和EPEC,不同年龄组的DEC型别构成不同。astA和pic是EAEC主要的毒力因子,ETEC以lt.sth.stp基因为主,部分菌株也含有astA和pic基因。DEC菌株对头孢唑林、氨苄西林、磺胺异恶唑耐药率较高,对碳青霉烯类、多肽类及三代头孢较为敏感,多重耐药菌株占60.37%。结论通州区DEC以EAEC为主,毒力基因组合具有多样性,astA和pic可在不同型别菌株中转移。菌株多重耐药情况比较严重,耐药基因易传播,应重视临床抗生素的使用。

Objective To investigate the etiological characteristics and drug resistance of diarrhea-causing Escherichia coli in patients with diarrhea in Tongzhou District,Beijing from 2016 to 2019. Methods Diarrheagenic Escherichia coli was isolated and cultured from stool samples of diarrhea surveillance cases in Tongzhou District from 2016 to 2019. The virulence gene of the strain was detected by fluorescent PCR method,and the drug resistance test was carried out by MIC method. Results From2016 to 2019,the detection rate of DEC was 13. 05%( 217/1 663) in Tongzhou District,and the detection rate increased year by year. The detection rate of DEC was highest in 20 to 39 years old group,followed by 0 to 5 years old group and ≥60 years old group. EAEC was the main type,followed by ETEC and EPEC. DEC types were different in different age groups. ast A and pic were the main virulence factors in EAEC,and lt,sth and stp genes were the main genes in ETEC. Some strains also contained ast A and pic genes. DEC strain had high drug resistance rate to cefazolin,ampicillin and sulfaisoxazole,and was sensitive to carbapenems,peptides and three generations of cephalosporins. The number of multi-drug resistant strains accounted for60. 37%. Conclusion DEC in Tongzhou District was dominated by EAEC,and the virulence gene combinations were diverse.ast A and pic could be transferred in different strains. The multiple drug resistance of the strain is serious,and the resistant gene is easy to spread,so the use of clinical antibiotics should be paid attention to.