Antimicrobial Susceptibility and Virulence of mcr-1-Positive Enterobacteriaceae in China, a Multicenter Longitudinal Epidemiological Study

Abstract

This study was to investigate the prevalence of mcr-1 -positive Enterobacteriaceae (MPE) in intra-abdominal infections (IAIs), urinary tract infections (UTIs), and lower respiratory tract infections (LRTIs) in China. A total of 6,401 Enterobacteriaceae isolates were collected consecutively from IAI, UTI, and LRTI patients in 19 hospitals across mainland China during 2014–2016. MPE isolates were screened by PCR detection for the mcr gene. The resistance profiles were tested by antimicrobial susceptibility test. All MPE isolates were characterized by pulsed-field gel electrophoresis (PFGE), multi-locus-sequence typing, O and H serotyping, and whole-genome sequencing. Among the 6,401 Enterobacteriaceae isolates, 17 Escherichia coli strains (0.27%) were positive for the mcr-1 gene. The MPE prevalence rates in IAI, UTI, and LRTI patients were 0.34% (12/3502), 0.23% (5/2154), and 0% (0/745), respectively. The minimum inhibition concentrations (MICs) of colistin against 3 isolates were of 0.5–2 mg/L, and 4–8 mg/L against other 14 isolates. All the 17 isolates were susceptible to meropenem, imipenem, tigecycline, and ceftazidime/avibactam. The 17 MPE isolates belonged to 14 different ST types, and those that belonged to the same STs were not clonal by PFGE. The mcr-1 -harboring plasmid of ten MPE isolates could transfer to the recipients by conjugation and the colistin MICs of the transconjugants ranged from 0.5 to 8 mg/L. M cr-1 -carrying plasmids from the 17 MPE isolates could be grouped into four clusters, including 8 IncX4 type, 4 IncI2 type, 4 IncHI2A type, and 1 p0111 type. Multiple-drug resistance genes and virulence genes were detected. In conclusion, the prevalence of MPE in IAI, UTI, and LRTI were low in China, and no clonal transmission was identified in our study. Most MPE isolates exhibited low-level colistin resistance. However, our study indicated that MPE isolates always carried a variety of drug resistance and virulence genes, which should be paid more attention.

High Prevalence of Extended-Spectrum Beta-Lactamases in Escherichia coli Strains Collected From Strictly Defined Community-Acquired Urinary Tract Infections in Adults in China: A Multicenter Prospective Clinical Microbiological and Molecular Study

“…This study also found that two of three colistin-resistant E. coli isolates carried bla CTX–M– 14 and bla TEM– 1 genes but were susceptible to carbapenems, which is consistent with a previous study ( Jiang et al, 2020 ). The results suggest we need to attach great importance to the management of MDR Gram-negative bacteria.…”

Colistin resistance genes inEscherichia coliisolated from patients with urinary tract infections

“…The detection of one isolate MCR -1 gene in E. coli urinary tract strains was proved by Multiplex PCR similarly, MCR -1 was shown in colistin-resistant E. coli isolates from China [31]. Single E. coli isolate that resisted colistin, was also resisted multiple classes of antimicrobials, but was susceptible to gentamicin, florfenicol, kanamycin, tigecycline, and fosfomycin.…”

Associated resistance of Escherichia coli isolated from humans and animals to polymyxin and beta-lactam antibiotics

“…По данным многоцентрового исследования в Китае в период 2014-2016 гг. частота mcr-позитивных изолятов среди возбудителей интраабдоминальных инфекций составила 0,34%, среди возбудителей инфекций мочевыводящих путей -0,23%, среди возбудителей инфекций дыхательных путей таких штаммов обнаружено не было [31]. При инфекциях кровотока частота выделения mcr-позитивных штаммов в Китае также не превышала 1% [32][33][34].…”