AUTHOR=Miao Zengmin , Li Song , Wang Lei , Song Wengang , Zhou Yufa 

TITLE=Antimicrobial Resistance and Molecular Epidemiology of ESBL-Producing Escherichia coli Isolated from Outpatients in Town Hospitals of Shandong Province, China

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00063

DOI=10.3389/fmicb.2017.00063

ISSN=1664-302X

ABSTRACT=<p>This study aimed to investigate antimicrobial resistance and molecular epidemiology of extended-spectrum β-lactamase (ESBL)-producing <italic>Escherichia coli</italic> (<italic>E. coli</italic>) isolated from outpatients in town hospitals of Shandong province, China. Antimicrobial susceptibility of ESBL-producing <italic>E. coli</italic> was tested using the disk diffusion and resistance genes encoding for β-lactamases (<italic>bla</italic><sub>TEM</sub>, <italic>bla</italic><sub>CTXM</sub>, and <italic>bla</italic><sub>SHV</sub>) were detected by polymerase chain reaction (PCR). Multilocus sequence typing (ST) of ESBL-producing <italic>E. coli</italic> was analyzed in this study. Our results showed that of 320 <italic>E. coli</italic> isolates, 201 carried ESBL genes (201/320, 62.8%), and these isolates all carried <italic>bla</italic><sub>CTX-M</sub> genes, the most common being <italic>bla</italic><sub>CTX-M-14</sub> (116/201, 57.7%), followed by <italic>bla</italic><sub>CTX-M-55</sub> (47/201, 23.4%) and <italic>bla</italic><sub>CTX-M-15</sub> (31/201, 15.4%). ESBL-producing <italic>E. coli</italic> exhibited highly resistant to penicillin derivatives, fluoroquinolones, folate pathway inhibitors, and third-generation cephalosporins, but no carbapenem-resistant isolates were found in this study. Forty-two STs were found among the 201 ESBL-producing <italic>E. coli</italic>, and the most common ST was ST131 (27/201, 13.4%), followed by ST405 (19/201, 9.5%) and ST69 (15/201, 7.5%). Taken together, a high isolation rate of ESBL-producing <italic>E. coli</italic> (62.8%) was found among outpatients in town hospitals. <italic>bla</italic><sub>CTX-M</sub> gene was most dominant and was composed of a variety of subtypes. No dominant ST was detected among ESBL-producing <italic>E. coli</italic>, indicating that these ESBL-producing <italic>E. coli</italic> isolates derive from different clones.</p>