Dataset Information

Co-Occurrence of NDM-9 and MCR-1 in a Human Gut Colonized Escherichia coli ST1011.

ABSTRACT:

Background

The emergence of the plasmid-borne colistin-resistant gene (mcr-1) poses a great threat to human health. What is worse, the recent observations of the coexistence of mcr-1 with carbapenemase encoding genes in some bacteria caused even more concern. Yet, there is a lack of observations of such strains in the human gut.

Methods

The isolation of E. coli L889 was performed on selective medium plates. Antibiotic susceptibilities were determined by an agar dilution and a broth microdilution method. Multi-locus sequence typing (MLST) and acquired resistance genes were also characterized. Transferability of bla _NDM-9/mcr-1-carrying plasmids was determined by conjugation, replicon typing and S1-Pulsed-field gel electrophoresis (S1-PFGE), and Southern blotting. The sequences of these plasmids were analyzed by using whole-genome sequencing with Illumina Novaseq and Nanopore platforms.

Results

E. coli L889 was identified as ST1101 concomitantly carrying bla _NDM-9 and mcr-1 from a stool sample. Antimicrobial susceptibility tests showed that it was resistant to various antimicrobial agents and only susceptible to tigecycline. Notably, bla _NDM-9 was located on a ~114-kb untypable plasmid, while mcr-1 was located on a ~63-kb IncI2 plasmid.

Conclusion

Our research, to our knowledge, first reported an ST1101 E. coli strain with an untypeable bla _NDM-9-harbouring plasmid and an IncI2 mcr-1-carrying plasmid. The colonized E. coli strains potentially contribute to the dissemination and transfer of bla _NDM-9 and mcr-1 to clinical isolates, which is a considerable threat to public health and should be closely monitored.

SUBMITTER: Liang G

PROVIDER: S-EPMC8370297 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background:The concurrence of mcr and carbapenemase genes among Enterobacteriaceae has been a great clinical concern. In our study, we aimed to investigate the prevalence of mcr-positive carbapenem-resistant Enterobacteriaceae (CRE) in fresh vegetables and shed light on the possibility of transmission of mcr-positive CRE via fresh vegetables. Methods:In this study, 712 fresh vegetable samples from 10 provinces in China were collected between May 2017 and Dec 2018 and were screened for mcr and carbapenemase genes. Antibiotic susceptibilities for isolates co-harboring carbapenemase genes and mcr were determined by an agar dilution or a broth microdilution method. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analysis were also performed. Transferability of the carbapenemase/mcr-bearing plasmids was determined by conjugation, replicon typing and S1-PFGE-Southern blotting. The sequences of these plasmids were analyzed by using whole-genome sequencing with Illumina Hiseq platform. Results:Two E. coli isolates concomitantly carrying mcr-1 and bla NDM-5/9 from leaf rape and spinach, respectively, were found and both isolates showed multidrug resistance. Notably, mcr-1-positive 690 harboring bla NDM-5 and 701 carrying bla NDM-9 belonged to ST156 and ST2847, respectively, similar to the prevalent MLST types of E. coli co-carrying mcr-1 and bla NDM from avian in our previous study. mcr-1 was on ~33-kb IncX4 plasmid or ~60-kb IncI2 plasmid, while bla NDM-5/9 was on ~46-kb IncX3 plasmid or ~120-kb untypable plasmid. The plasmids were highly similar to those from animals and clinical patients reported in various countries.Conclusion: E. coli isolates concomitantly carrying mcr-1 and bla NDM-5/9 in fresh vegetables may serve as a direct source of pathogens in humans, and such discovery in fresh vegetables emphasizes the importance of prompt surveillance and intervention in limiting the spread of E. coli co-carrying bla NDM and mcr-1. To our knowledge, this is the first report of Enterobacteriaceae co-carrying bla NDM and mcr-1 in fresh vegetables.