Genomic and Molecular Characterization of Clinical Isolates of Enterobacteriaceae Harboring mcr-1 in Colombia, 2002 to 2016

Yamile Saavedra, Sandra; Diaz, Lorena; Wiesner, Magdalena; Correa, Adriana; Alejandra Arevalo, Stefany; Reyes, Jinnethe; Melissa Hidalgo, Andrea; de la Cadena, Elsa; Perenguez, Marcela; Angeline Montano, Lucy; Ardila, Javier; Rios, Rafael; Victoria Ovalle, Maria; Diaz, Paula; Porras, Paola; et. al.

Abstract

Polymyxins are last-resort antimicrobial agents used to treat infections caused by carbapenem-resistant Enterobacteriaceae. Due to the worldwide dissemination of polymyxin resistance in animal and human isolates, we aimed to characterize polymyxin resistance associated with the presence of mcr-1 in Enterobacteriaceae and nonfermenter Gram-negative bacilli, using isolates collected retrospectively in Colombia from 2002 to 2016. A total of 5,887 Gram-negative clinical isolates were studied, and 513 were found to be resistant to the polymyxins. Susceptibility to colistin was confirmed by broth microdilution for all mcr-1-positive isolates, and these were further subjected to whole-genome sequencing (WGS). The localization of mcr-1 was confirmed by S1 pulsed-field gel electrophoresis (S1-PFGE) and CeuI-PFGE hybridization. Transferability was evaluated by mating assays. A total of 12 colistin-resistant isolates recovered after 2013 harbored mcr-1, including 8 Escherichia coli, 3 Salmonella enterica serovar Typhimurium, and 1 Klebsiella pneumoniae isolate. E. coli isolates were unrelated by PFGE and belonged to 7 different sequence types (STs) and phylogroups. S. Typhimurium and K. pneumoniae isolates belonged to ST34 and ST307, respectively. The mcr-1 gene was plasmid borne in all isolates but two E. coli isolates which harbored it on the chromosome. Conjugation of mcr-1 was successful in 8 of 10 isolates (8.2 x 10(-5) to 2.07 x 10(-1) cell per recipient). Plasmid sequences showed that the mcr-1 plasmids belonged to four different Inc groups (a new IncP-1 variant and the IncFII, IncHI1, and IncH families). Our results indicate that mcr-1 is circulating in clinical isolates of colistin-resistant Enterobacteriaceae in Colombia and is mainly harbored in transferable plasmids.

Más información

Título según WOS: ID WOS:000416578900010 Not found in local WOS DB
Título de la Revista: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
Volumen: 61
Número: 12
Editorial: AMER SOC MICROBIOLOGY
Fecha de publicación: 2017
DOI:

10.1128/AAC.00841-17

Notas: ISI