High Prevalence of blaNDM Variants Among Carbapenem-Resistant Escherichia coli in Northern Jiangsu Province, China

Abstract

The continuous emergence of carbapenem-resistant Escherichia coli (CRECO) presents a great challenge to public health. New Delhi metallo-lactamase (NDM) variants are widely disseminated in China, so the research on the prevalence and transmission of diverse blaNDM variants is urgently needed. In the present study, 54 CRECO isolates were collected from 1,185 Escherichia coli isolates in five hospitals in Northern Jiangsu Province, China from September 2015 to August 2016. Antimicrobial susceptibility tests, PCR detection of resistance determinants, multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were performed to characterize these strains. Plasmid conjugation experiments were carried out to determine the transferability of resistant genes from selected isolates. PCR-based replicon typing (PBRT), S1 nuclease-PFGE, and Southern blotting were conducted for plasmid profiling. Carbapenemase genes were detectable in all CRECO isolates, among which thirty-one CRECO isolates were found to carry blaNDM−5 (54.7%), while, blaNDM−1, blaNDM−7, blaNDM−4, blaNDM−9, and blaKPC−2 were identified in 14, five, two, one, and one isolates, respectively. MLST results revealed 15 different STs and four new STs were first reported to be linked with NDM-producing isolates. PFGE typing showed that no more than two isolates with the same ST appeared to the same band pattern except three ST410 isolates. Twenty-six selected NDM-producing isolates were successfully transferred to E. coli J53 by conjugation experiments. Notably, 50.0% (13/26) of blaNDM variants were found to be carried by ~55 kb IncX3 plasmid. Our study reported a high prevalence of blaNDM variants, especially blaNDM−5, in Northern Jiangsu province, China. Diverse blaNDM variants were mainly carried by ~55 kb IncX3 plasmids, suggesting that the fast evolution and high transferability of this kind of plasmid promote the high prevalence of blaNDM variants. Therefore, large-scale surveillance and effective infection control measures are also urgently needed to prevent diverse blaNDM variants from becoming epidemic in the future.

Genomic characterization of carbapenem resistant Escherichia coli from multiple hospitals in Nanjing, China: focusing on frequent co-occurrence of blaNDM and blaKPC-2

“…The multiple distinct STs identi ed in our study indicated the diversity of these CREC, which was also con rmed by the phylogenetic relationship. NDM-5 has been reported in E.coli ST410, ST156, and ST167 (20). However, to the best of our knowledge, NDM-5 producing E. coli ST297, ST683 and ST3489, as well as NDM-1 producing E. coli ST361 has not been reported previously.…”

“…For the 6 isolates co-carrying blaKPC and blaNDM, broth mating was performed in order to analyze the transferability of these genes according to the protocol prescribed previously (20). Azide resistant E. coli J53 was used as the recipient.…”

The prevalence and mechanism of triclosan resistance in Escherichia coli isolates from urine samples in Wenzhou, China

“…All the triclosan non-susceptible isolates were typed using MLST method. [24]. Salmonella standard strain H9812 was taken as the positive control.…”

Genomic characterization of carbapenem resistant Escherichia coli from multiple hospitals in Nanjing, China: focusing on frequent co-occurrence of blaNDM and blaKPC-2 

“…For the 6 isolates co-carrying blaKPC and blaNDM, broth mating was performed in order to analyze the transferability of these genes according to the protocol prescribed previously (24). Azide resistant E. coli J53 was used as the recipient.…”

“…It is worthy to note that the co-occurrence of multiple ß-lactamases among single bacteria species (7), especially carbapenemase, such as co-production of NDM-1 and Klebsiella pneumoniae carbapenemase 2 (KPC-2)(8), co-occurrence of KPC-2 and OXA-48, have so far been frequently described in multiple clinical Enterobacterales, such as K. pneumoniae, Enterobacter cloacae, and Citrobacter freundi (8)(9)(10). Thus, such a frequent co-occurrence of carbapenemase in one isolate are causing rapidly rising carbapenem resistance, leading to increasing CREassociated morbidity and mortality (11) Report from the China CRE Network showed that the overall CREC infection incidence differed signi cantly by region, with the highest in Shandong (9.1%) and the lowest in Qinghai (0 %) during January to December 2015 (12); another study showed a 4.6% prevalent rate of CREC in in Northern Jiangsu Province, China during September 2015 to August 2016 (13). However, strains analyzed were predominantly collected from tertiary hospitals.…”