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

Sequence type 1193 is emerging as a new, virulent and resistant lineage among fluoroquinolone resistant (FQ ). In this study, we investigated the prevalence and molecular characteristics of this clone isolated from a Chinese university hospital. 73 phylogenetic group B2-FQ -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. ST1193 then underwent lactose fermentation determination, susceptibility testing, virulence genotyping, PCR-based O typing, pulsed-field gel electrophoresis (PFGE) and FQ mechanism analysis. Of 73 B2-FQ -non ST131 isolates, 69.9% ( = 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 ( S83L, D87N, and S80I). The most frequent VF genes detected in these ST1193 isolates were (yersiniabactin, 96.1%), (type 1 fimbriae, 94.1%), (iron uptake gene, 90.2%), (group II capsule, 90.2%), (K1 capsule, 86.3%) and PAI. ST1193 lineage accounts for the majority of group B2-FQ -non-ST131 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 : B2-FQ -ST1193.