摘要目的：了解上海市普陀区老年患者分离的尿路致病性大肠埃希菌（UPEC）的分子流行病学特征和耐药特征。方法收集上海中医药大学附属普陀医院2013年1月至2015年3月自泌尿道感染住院老年患者分离的72株 UPEC ，进行多位点序列分型（MLST ），检测β‐内酰胺酶基因和质粒介导的喹诺酮耐药基因（PMQR），检测 gyrA 和 parC 基因喹诺酮耐药决定区（QRDR）基因突变，并进行体外药物敏感试验。均数比较采用 t 检验，率的比较采用χ2检验或 Fisher 确切概率法。结果UPEC 对环丙沙星、头孢噻肟、复方磺胺甲口恶唑的耐药率分别为76．4％、73．6％、65．3％，而对亚胺培南、美罗培南、阿米卡星、哌拉西林‐他唑巴坦仍保持高度敏感。72株 UPEC 中，55株（76．4％）为超广谱β‐内酰胺酶（ESBL）阳性菌株，其中49株（68．1％）携带 blaCTX‐M 基因。在55株对环丙沙星耐药的菌株中，51株（92．7％）UPEC gyrA 和 parC 基因 QRDR 均有3～4个位点的错义突变，突变热点为 gyrA的83位、87位氨基酸和 parC 的80位、84位氨基酸。72株 UPEC 中最常见 ST 型为 ST131（18／72，25．0％）、ST1193（7／72，9．7％）、ST405（7／72，9．7％）、ST38（5／72，6．9％）和 ST648（3／72，4．2％）。ST131为导致社区获得性泌尿道感染的优势 ST 型。 ST131、ST405、ST38和 ST648表现出多重耐药特性，大多数为产 CTX‐M 型 ESBL 。结论本研究的社区老年患者携带的 UPEC 中存在以 ST131克隆为代表的多重耐药菌株流行，需要加强监测，预防其广泛流行。

abstractsObjective To investigate the molecular epidemiology and antimicrobial resistance status of uropathogenic Escherichia coli (UPEC) in senior population in Putuo District ,Shanghai .Methods A total of 72 UPEC strains were isolated from elderly inpatients with urinary tract infections in Putuo Hospital ,Shanghai University of Traditional Chinese Medicine from January 2013 to March 2015 .The strains were characterized by multi‐locus sequence typing (MLST ) .The β‐lactamase gene and the plasmid mediated quinolone resistance (PMQR) gene were detected ,and the mutations of quinolone resistance‐determining regions (QRDR) in gyrA and parC genes were demonstrated .In vitro drug susceptibility test was performed .Continuous variables were compared using t test and categorical variables were compared using chi‐squared test or Fisher exact test .Results The UPEC strains showed different resistance rates to ciprofloxacin ,cefotaxime and trimethoprim‐sulfamethoxazole ,which were 76 .4% ,73 .6% and 65 .3% , respectively .UPEC still remained highly sensitive to imipenem ,meropenem ,amikacin and piperacillin‐tazobactam .Among 72 isolates ,55 (76 .4% ) of 49 (68 .1% ) extended‐spectrum β‐lactamase (ESBL )‐positive strains harbored blaCTX‐M genes .Among the 55 ciprofloxacin resistant strains ,51 (92 .7% ) had three or four mutations in QRDR of gyrA and parC genes .The “hot‐spot” mutations of QRDR were located at amino acid position 83 and 87 in gyrA gene and at positions 80 and 84 in parC gene .Forward analysis by MLST showed that the most frequent sequence types (ST ) were ST131 (18/72 ,25 .0% ) , ST1193(7/72 ,9 .7% ) ,ST405 (7/72 ,9 .7% ) ,ST38 (5/72 ,6 .9% ) and ST648 (3/72 ,4 .2% ) .ST131 isolates were predominant in ST which caused community‐onset urinary tract infections .Multiple drug‐resistance were detected in ST 131 ,ST405 ,ST38 and ST648 which were mainly producing blaCTX‐M ESBL .Conclusions Community‐acquired multiple drug‐resistant UPEC strains such as ST131 clone are prevalent in elderly patients .Thus ,monitoring of molecular epidemiology would be beneficial to prevent the prevalence of multiple drug‐resistant UPEC .