First Detection of Colistin Resistance Encoding Gene mcr-1 in Clinical Enterobacteriaceae isolates in Morocco

Background and Objective: Since first reported in 2015, the mobile colistin resistance gene (MCR-1) has been found in increasing numbers worldwide. However, only a few studies have been carried out in Morocco. This study aimed to examine the profile of colistin resistance and MCR-genes within the human Enterobacteriaceae isolates of northwest Morocco. Materials and Methods: MCR-genes were investigated among 338 Enterobacteriaceae isolates, including Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), Enterobacter ssp, Citrobacter freundii (C. freundii), and, Proteus mirabilis (P. mirabilis). All isolates were collected from Tangier and Tetouan between December 2020 and May 2021. Susceptibility tests were performed using the disc diffusion assay and minimal inhibitory concentrations (MIC). PCR and DNA sequencing techniques were used to screen and confirm the presence of MCR genes (MCR-1- MCR-5). Results: 22.78% of the isolates in this study were multidrug-resistant (MDR), among which 57.14% of P. mirabilis isolates, 30% of Enterobacter isolates, 22.22% of K. pneumoniae isolates, and 22.05% of E. coli isolates. Colistin resistance was found in 51 of 338 isolates, including 33 E. coli, 11 K. pneumoniae, and 7 P. mirabilis. Only three MCR-1 genes were detected. Furthermore, no MCR-2 to MCR-5 genes were found. Sequencing of our PCR products showed 99–100% similarity to MCR-1 genes. Conclusion: This is the first study in Morocco to investigate the prevalence of colistin resistance among human isolates, and it has revealed the first MCR-1 genes circulating in human isolates in Morocco. This could lead to the dissemination of these genes throughout Morocco.

First Detection of Colistin Resistance Encoding Gene mcr-1 in Clinical Enterobacteriaceae isolates in Morocco Keywords:

Colistin , Enterobacteriaceae , Escherichia coli , MCR genes , Morocco