Identification of Mammaliicoccus fleurettii as the source of a methicillin-resistant gene in a First Nation reserve lake in Manitoba, Canada.

Our study aimed to identify the bacterial source of a previously detected mobile antibiotic-resistant gene, mecA, found in a lake that serves as a source to a water treatment plant operated by a First Nation reserve. Three methicillin-resistant presumptive Staphylococcus spp. isolated from the sample using selective media were verified as mecA positive by PCR. MALDI-TOF and whole-genome sequencing of each isolate confirmed that all three were Mammaliicoccus fleurettii. Antibiotic-resistant gene analysis of the assembled genomes predicted mecA with 99.7% sequence identity, and phylogenetic analysis grouped our three mecA genes with the mecA allele from a methicillin-resistant strain of Staphylococcus aureus. Identifying microbial species known to harbour mobile antibiotic-resistant elements can provide greater depth of information about drinking water, an especially essential need in First Nation reserves where water quality too frequently is poor.