Molecular characteristics of the new emerging global clone ST1193 among clinical isolates of Escherichia coli from neonatal invasive infections in China

Sequence type 1193 (ST1193) constitutes an emerging fluoroquinolone-resistant Escherichia coli clone in several countries. However, reports of such isolates in neonatal invasive diseases are limited. Here, we assessed the antimicrobial resistance and molecular characteristics of E. coli ST1193 isolates causing neonatal bloodstream infections and meningitis in China. A total of 56 E. coli isolates were collected from neonatal blood and cerebrospinal fluid between September 2009 and June 2015. Antimicrobial susceptibility was evaluated using E-test methods. Polymerase chain reaction amplification was used to detect antibiotic resistance genes including bla TEM , bla SHV , and bla CTX-M groups. Molecular typing was performed via multi-locus sequence typing. Among 56 E. coli isolates, 17 (17/56, 30.4%) were extended-spectrum β-lactamase (ESBL) producers, and 37(37/56, 66.1%) were multidrug-resistant. The most frequent sequence types were ST1193 (12/56), followed by ST95 and ST62. ST1193 isolates exhibited a 91.7% resistance rate to ciprofloxacin, amoxicillin, and sulfonamides, and 83.3% resistance rate to tetracycline. A total of 4 (33.3%) among the 12 ST1193 isolates were ESBL producers, of which three carried both bla CTX-M-15 and bla TEM genes with the remaining isolate harboring bla CTX-M-27 and bla TEM genes. Additionally, 1 of the 3 ST1193 isolates obtained from cerebrospinal fluid was an ESBL producer that carried both bla CTX-M - 15 and bla TE M genes. This study revealed for the first time the molecular characteristics of E. coli ST1193 causing neonatal invasive diseases in China. Notably, we found that ST1193 isolates were multidrug-resistant. Further multicenter studies are needed to assess the molecular epidemiology of ST1193 in China to control its spread.