First report of plasmid-mediated colistin resistance mcr-8.1 gene from a clinical Klebsiella pneumoniae isolate from Lebanon

Colistin is considered as a last resort treatment for infections caused by multidrug-resistant Enterobacteriaceae. Plasmid-mediated mobile colistin resistance (mcr) genes contributed to the global spread of colistin resistance. This is the first report of plasmid-mediated colistin resistance mcr-8 gene from a clinical Klebsiella pneumoniae K9 isolate recovered from Lebanon. The isolate was characterized phenotypically and genotypically through both short and long read whole-genome sequencing, plasmid typing and conjugation assays. k9 belonged to sequence type 15 and harbored 31 antimicrobial resistance genes. The mcr-8.1 variant was carried on a novel ~ 300 kb multireplicon plasmid having IncFIA, IncR and IncHI1B. The plasmid was conjugative and carried a plethora of antimicrobial resistance determinants. The introduction of novel mcr variants in Lebanon poses an alarming health concern. Surveillance and screening for colistin resistant Enterobacteriaceae and mcr in livestock, animal farms, imported meat and poultry is highly recommended along with monitoring antibiotic use.