First Detection of Colistin Resistance Encoding Gene mcr-۱ in Clinical Enterobacteriaceae isolates in Morocco

Background and Objective: Since first reported in ۲۰۱۵, the mobile colistin resistance gene (MCR-۱) 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 ۳۳۸ 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 ۲۰۲۰ and May ۲۰۲۱. 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-۱- MCR-۵). Results: ۲۲.۷۸% of the isolates in this study were multidrug-resistant (MDR), among which ۵۷.۱۴% of P. mirabilis isolates, ۳۰% of Enterobacter isolates, ۲۲.۲۲% of K. pneumoniae isolates, and ۲۲.۰۵% of E. coli isolates. Colistin resistance was found in ۵۱ of ۳۳۸ isolates, including ۳۳ E. coli, ۱۱ K. pneumoniae, and ۷ P. mirabilis. Only three MCR-۱ genes were detected. Furthermore, no MCR-۲ to MCR-۵ genes were found. Sequencing of our PCR products showed ۹۹–۱۰۰% similarity to MCR-۱ 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-۱ genes circulating in human isolates in Morocco. This could lead to the dissemination of these genes throughout Morocco.

Keywords:

Colistin , Enterobacteriaceae , Escherichia coli , MCR genes , Morocco