<p>Prevalence Of <em>mcr-1</em> Among Cefotaxime-Resistant Commensal <em>Escherichia coli</em> In Residents Of Vietnam</p>

Abstract

PurposeThe dissemination of colistin-resistant bacteria harboring the colistin-resistance gene mcr-1 in developing countries has recently entered the spotlight as an emerging public health threat, which is attributed to the abuse of colistin use in these countries. However, the prevalence of these bacteria in developing countries has not been extensively investigated. Therefore, in the present study, we examined the prevalence of cefotaxime-resistant commensal Escherichia coli harboring mcr-1 among residents of a representative Vietnamese village and assessed the characteristics of these isolates.Materials and methodsThe stool samples, one stool sample per resident, of 612 residents were cultured on MacConkey agar with cefotaxime. Resulting E. coli-like colonies were isolated and examined further for the presence of colistin-resistant extended-spectrum β-lactamase (ESBL)-producing E. coli with mcr-1. Antibiotic susceptibility tests were performed, and clonal relationship among colistin-resistant isolates was assessed.ResultsThirty-one of the 451 cefotaxime-resistant E. coli isolates were resistant to colistin and the majority possessed mcr-1, blaCTX-M, and/or blaTEM, except for two isolates that produced the AmpC β-lactamase. All mcr-1 ESBL-producing E. coli isolates were multidrug-resistant (5–11 antibiotics). The isolates contained various plasmid replicon types, including the most prevalent types IncHI2 (54.8%), IncFIB (48.4%), and IncN (41.9%). In addition, 83.9% of the mcr-1 ESBL-E. coli isolates possessed a transposon ISApl1-mcr-1 segment. Furthermore, 77.4% of the mcr-1 ESBL-E. coli isolates belonged to phylogenetic group A. Pulsed-field gel electrophoresis analysis indicated limited clonal expansion of a specific strain.ConclusionThese results demonstrate the wide dissemination of colistin-resistant ESBL-E. coli harboring mcr-1 among commensal bacteria of rural residents in Vietnam, suggesting possible mobilization of the mcr-1 gene among ESBL-producing microbiota, which is a great public health concern.

High Prevalence of Colistin-Resistant Escherichia coli with Chromosomally Carried mcr-1 in Healthy Residents in Vietnam

“…The chromosomal mcr-1-carrying bacteria may contribute to the emergence of untreatable MDR bacteria when MDR genes, including carbapenem resistance genes on the plasmid (14), are transferred to bacteria possessing chromosomal mcr. In fact, this likelihood is supported by our current study, wherein several extended-spectrum ␤-lactamase (ESBL)-producing E. coli isolates that had MDR with mcr-1 were obtained from fecal microbiota of healthy human residents of the community (15).…”

Occurrence and Molecular Characteristics of Mcr-1-Positive Escherichia coli from Healthy Meat Ducks in Shandong Province of China

“…In this study, two IncI2 plasmids were obtained from the same farm, whereas the other five plasmids were respectively recovered from different farms. As a common mcr -disseminator, IncI2 plasmid was identified in isolates from animals, vegetables, and humans [ 49 , 54 , 55 ]. These results suggest that diversified conjugative plasmids, especially IncI2 plasmid, may be the key vectors that mediate the dissemination of the mcr-1 among Enterobacteriaceae [ 56 ].…”

Quantitative Analysis of Colistin-Resistant Escherichia coli in Retail Meat from Local Vietnamese Markets

“…coli strains isolated from healthy residents during 2013–2016 in the Thai Binh Province of Vietnam showed that 6.9% of the ESBL-producing E . coli strains possessed mcr-1 [ 9 ]. Another study from the same area conducted during 2017–2018 showed that approximately 70% of healthy residents carried CR E .…”

“…Supporting this hypothesis, Kawahara et al [8] reported that in a rural area of Vietnam, approximately 100% chicken and pig fecal samples contained CR Escherichia coli with mcr-1 or mcr-3. A retrospective study on extended-spectrum β-lactamase-(ESBL-) producing E. coli strains isolated from healthy residents during 2013-2016 in the Thai Binh Province of Vietnam showed that 6.9% of the ESBL-producing E. coli strains possessed mcr-1 [9]. Another study from the same area conducted during 2017-2018 showed that approximately 70% of healthy residents carried CR E. coli with mcr-1 and/or mcr-3, and that 92.8% of those isolates were multidrug resistant [10].…”