2014～2018年北京市人源性肠产毒性大肠埃希菌耐药性与PFGE分子分型研究

Antimicrobial resistance and molecular typing characteristics of enterotoxigenic Escherichia coli from diarrheal patients in Beijing from 2014 to 2018

目的分析北京市门诊腹泻病例肠产毒性大肠埃希菌(enterotoxigenic Escherichiacoli,ETEC)分离株抗生素敏感性及分子分型特征。方法采用微量肉汤稀释法对2014~2018年北京市门诊腹泻病例ETEC分离株进行8大类14种抗生素敏感性检测。参照PulseNet中非O157大肠埃希菌脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)分型方法,对不同区县不同采样时间分离的菌株采用随机抽样原则,对178株菌基因组经限制性内切酶Xba I酶切后进行分子分型和聚类分析。结果 578株2014~2018年北京市门诊腹泻病例ETEC菌株总耐药率为94.29%,对萘啶酸、氨苄西林、头孢唑林耐药率较高,分别为61.58%、60.38%、36.19%。578株菌分为152个耐药谱,耐3种及3种以上抗生素的菌株数达340株(59.00%),有1株菌对12种抗生素耐药。常见耐药谱为耐喹诺酮类的萘啶酸,占20.18%,其次为耐β-内酰胺类的氨苄西林-头孢唑林-头孢噻肟,占12.29%,再次为耐β-内酰胺类的氨苄西林-喹诺酮类的萘啶酸-大环内酯类的阿奇霉素,占6.79%,且耐药谱种类逐年缓慢上升。其中178株菌共产生153种PFGE带型,带型分布较为分散,无优势带型,菌株之间的相似系数为31.60%~100.0%。结论 2014~2018年北京市腹泻病例肠产毒性大肠埃希菌耐药情况严重,耐药谱复杂广泛,多重耐药菌株占比呈逐年缓慢上升趋势。PFGE带型呈多态性分布。

Objective To investigate the antibiotic sensitivity and molecular typing characteristics of enterotoxigenic Escherichia coli(ETEC)isolates in outpatient diarrhea cases in Beijing.Methods Microbroth dilution method was used to detect the sensitivity of 8 categories of 14 kinds of antibiotics of ETEC isolates in outpatient diarrhea cases in Beijing from 2014 to 2018.According to the pulsed-field gel electrophoresis(PFGE)typing method in PulseNet,the random sampling principle was adopted for the strains isolated from different sampling periods in different districts and counties,and the genome of 178 strains was digested by restriction enzyme Xba I for molecular typing and clustering analysis.Results The total resistance rate of 578 strains of ETEC strains in outpatients with diarrhea in Beijing from 2014 to 2018 was 94.29%,and the resistance rates to nalidixic acid,ampicillin and cefazolin were 61.58%,60.38%and 36.19%,respectively.The 578 strains are divided into 152 resistant spectrums.The 340 strains were resistant to 3 or more antibiotics(59.00%),and 1 strain was resistant to 12 antibiotics.The common drug resistance spectrum was nalidixic,accounting for 20.18%,followed byampicillincefazolin-cefotaxime,accounting for 12.29%,and ampicillin-nalidixic-azithromycin accounting for 6.79%,and the type of drug resistance spectrum slowly increased year by year.Among them,178 strains produced 153 kinds of PFGE bands,and the band type distribution was more dispersed.There was no dominant band type,and the similarity coefficients between the strains were 31.60%-100.0%.Conclusion From 2014 to 2018,the incidence of enterotoxic Escherichia coli in diarrhea cases in Beijing is serious,and the drug resistance spectrum is complex.The proportion of multi-drug resistant strains increase slowly year by year.PFGE band type is polymorphic.