Genetic analysis of the first mcr-1 positive Escherichia coli isolate collected from an outpatient in Chile

Publication date: Available online 20 June 2019Source: The Brazilian Journal of Infectious DiseasesAuthor(s): Camila Gutiérrez, Javier Zenis, Paulette Legarraga, Jaime Cabrera-Pardo, Patricia García, Helia Bello-Toledo, Andrés Opazo-Capurro, Gerardo González-RochaAbstractGlobal dissemination of mcr-like genes represents a serious threat to public health since it jeopardizes the effectiveness of colistin, an antibiotic used as a last-resort treatment against highly antibiotic-resistant bacteria. In 2017, a mcr-1-positive isolate was found in Chile for the first time. Herein we report the genetic features of this strain (UCO-457) by whole-genome sequencing (WGS) and conjugation experiments. The UCO-457 strain belonged to ST4204 and carried a 285 kb IncI2-type plasmid containing the mcr-1 gene. Moreover, this plasmid was transferred by conjugation to an E. coli J53 strain at high frequency. The isolate harbored the cma, iroN, and iss virulence genes and did carry resistance genes to rimethoprim/sulfamethoxazole and fluoroquinolones. Other antibiotic resistance determinants such as β-lactamases-encoding genes were not detected, making the isolate highly susceptible to these antibiotics. Our results revealed that such susceptible isolates could be acting as platforms to disseminate plasmid-mediated colistin resistance. Based on this evidence, we consider that mcr-like prevalence deserves urgent attention and should be examined not only in highly resistant bacteria but also ...
Source: The Brazilian Journal of Infectious Diseases - Category: Infectious Diseases Source Type: research