AUTHOR=Wu Jing , Lan Fangjun , Lu Yanfang , He Qingwen , Li Bin 

TITLE=Molecular Characteristics of ST1193 Clone among Phylogenetic Group B2 Non-ST131 Fluoroquinolone-Resistant Escherichia coli

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.02294

DOI=10.3389/fmicb.2017.02294

ISSN=1664-302X

ABSTRACT=<p><bold>Objectives:</bold> Sequence type 1193 is emerging as a new, virulent and resistant lineage among fluoroquinolone resistant <italic>Escherichia coli</italic> (FQ<sup>r</sup><italic>E. coli</italic>). In this study, we investigated the prevalence and molecular characteristics of this clone isolated from a Chinese university hospital.</p><p><bold>Methods:</bold> 73 phylogenetic group B2-FQ<sup>r</sup>-non-ST131 isolates were collected from August 2014 and August 2015 at a Chinese university hospital. Isolates were screened for ST1193 by multilocus sequence typing. <italic>E. coli</italic> ST1193 then underwent lactose fermentation determination, susceptibility testing, virulence genotyping, PCR-based O typing, pulsed-field gel electrophoresis (PFGE) and FQ<sup>r</sup> mechanism analysis.</p><p><bold>Results:</bold> Of 73 B2-FQ<sup>r</sup>-non ST131 <italic>E. coli</italic> isolates, 69.9% (<italic>n</italic> = 51) were ST1193. 90.2% (46/51) of ST1193 isolates were O75 serotype and 96.1% (49/51) of the ST1193 isolates were lactose non-fermenters. 35 clusters were identified by PFGE. ST1193 isolates exhibited a set of 3 conserved mutations defining quinolone-resistance determining region substitutions (<italic>gyrA</italic> S83L, D87N, and <italic>parC</italic> S80I). The most frequent VF genes detected in these <italic>E. coli</italic> ST1193 isolates were <italic>fyuA</italic> (yersiniabactin, 96.1%), <italic>fimH</italic> (type 1 fimbriae, 94.1%), <italic>iutA</italic> (iron uptake gene, 90.2%), <italic>kpsMT II</italic> (group II capsule, 90.2%), <italic>kpsK1</italic> (K1 capsule, 86.3%) and PAI.</p><p><bold>Conclusion:</bold> ST1193 lineage accounts for the majority of group B2-FQ<sup>r</sup>-non-ST131 <italic>E. coli</italic> clinical isolates. Most of the ST1193 are serotype O75 and lactose non-fermenting. Strategic surveillance and control schemes are needed in the future for this newly emerging clone of <italic>E. coli</italic>: B2-FQ<sup>r</sup>-ST1193.</p>