The high frequency of fluoroquinolone resistance inEscherichia coliis a feature of clinical bacteriology in China, where the molecular epidemiology and genetic characteristics of this resistance in county hospitals remain unclear. A total of 590 nonduplicateE. coliisolates from 30 county hospitals located across seven Chinese regions were examined for plasmid-mediated quinolone resistance (PMQR) genes and mutations in quinolone resistance-determining regions (QRDRs). Multilocus sequence typing (MLST) and phylogenetic analysis of fluoroquinolone-resistant isolates were used to determine their genetic relatedness. The ciprofloxacin resistance rate of community-onsetE. coliwas 51.2%, and at least one PMQR gene was carried by 220 (37.3%) isolates. These includedqnr(3.7%),aac(6′)-Ib-cr(19.7%),qepA(14.4%), andoqxAB(3.8%). Two noveloqxBmutants were identified and namedoqxB20andoqxB29. From 60 sequence types (STs) isolated, 5 novel STs (ST4499 to ST4503) were identified. ST1193 (7.9%) was the second most abundant ST among fluoroquinolone-resistant isolates (ST131 was the most common, with 14.6%), and this is the first report of it in China. This is also the first report of ST2115 and ST3014 isolates from human samples. Ciprofloxacin-resistantE. coliisolates fell mainly into phylogroups B2 and D. The rates of fluoroquinolone resistance and the prevalence of PMQR genes in community-onsetE. coliisolates from Chinese county hospitals were high. The wide-ranging molecular epidemiology ofE. coliisolates from scattered locations across China indicates that fluoroquinolone resistance evolved from different sources.
First report regarding molecular epidemiology and novel variant identification of Anaplasma centrale in cattle from Pakistan
