Heterogeneity and Diversity of mcr-8 Genetic Context in Chicken-Associated Klebsiella pneumoniae.
Antimicrob Agents Chemother
; 65(1)2020 12 16.
Article
em En
| MEDLINE
| ID: mdl-33046490
ABSTRACT
Increasing mobile colistin resistance, mediated by the mcr gene family, in Enterobacteriaceae has become a global concern. Among the 10 reported mcr genes, mcr-8 was first identified in Klebsiella pneumoniae, which could cause severe infections with high mortality. Information about the prevalence and genetic context of mcr-8 is still lacking. In this study, we found that mcr-8 was present in 9.83% of K. pneumoniae isolates of chicken origin. S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting showed that the mcr-8 gene was located on a plasmid in all of the isolates. The genetic context of the plasmids exhibited considerable diversity from the whole-genome sequence through Illumina and MinION long-read sequencing. Mutations in two-component systems may function synergistically with mcr-8, resulting in extremely high resistance to colistin. In addition to colistin resistance, these plasmids also contained genes conferring resistance to beta-lactams, tetracycline, aminoglycosides, sulfonamides, macrolides, chloramphenicol, and florfenicol. Therefore, these findings indicate that the genetic context of mcr-8 is heterogeneous and diverse and that mcr-8 and certain chromosomal mechanisms jointly contribute to high-level colistin resistance in K. pneumoniae strains, which provides new insights into the resistance mechanisms of K. pneumoniae.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Escherichia coli
/
Klebsiella pneumoniae
Tipo de estudo:
Prognostic_studies
/
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article