ABSTRACT
Objective 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 .