Klebsiella pneumoniae co-harbouring bla_NDM-1, armA and mcr-10 isolated from blood samples in Myanmar

Background. The spread of Enterobacteriaceae coproducing carbapenemases, 16S rRNA methylase and mobile colistin resist-ance proteins (MCRs) has become a serious public health problem worldwide. This study describes two clinical isolates of Klebsiella pneumoniae coharbouring bla(IMP-1), armA and mcr-10.Methods. Two clinical isolates of K. pneumoniae resistant to carbapenems and aminoglycosides were obtained from two patients at a hospital in Myanmar. Their minimum inhibitory concentrations (MICs) were determined by broth microdilution methods. The whole-genome sequences were determined by MiSeq and MinION methods. Drug-resistant factors and their genomic environments were determined.Results. The two K. pneumoniae isolates showed MICs of >= 4 and >= 1024 mu g ml(-1) for carbapenems and aminoglycosides, respectively. Two K. pneumonaie harbouring mcr-10 were susceptible to colistin, with MICs of <= 0.015 mu g ml(-1) using cation-adjusted Mueller-Hinton broth, but those for colistin were significantly higher (0.5 and 4 mu g ml(-1)) using brain heart infusion medium. Whole-genome analysis revealed that these isolates coharboured bla(NDM-1), armA and mcr-10. These two isolates showed low MICs of 0.25 mu g ml(-1) for colistin. Genome analysis revealed that both bla(NDM-1) and armA were located on IncFIIs plasmids of similar size (81 kb). The mcr-10 was located on IncM2 plasmids of sizes 220 or 313 kb in each isolate. These two isolates did not possess a qseBC gene encoding a two-component system, which is thought to regulate the expression of mcr genes. Conclusion. This is the first report of isolates of K. pneumoniae coharbouring bla(NDM-1), armA and mcr-10 obtained in Myanmar.