Fitness cost of mcr-1-mediated polymyxin resistance in Klebsiella pneumoniae

摘要: Objectives The discovery of mobile colistin resistance mcr-1, a plasmid-borne polymyxin gene, highlights the potential for widespread to last-line polymyxins. In present study, we investigated impact mcr-1 acquisition on and biological fitness in Klebsiella pneumoniae. Methods K. pneumoniae B5055 was used as parental strain construction strains carrying vector only (pBBR1MCS-5) recombinant plasmids (pmcr-1). Plasmid stability determined by serial passaging 10 consecutive days antibiotic-free LB broth, followed patching gentamicin-containing agar plates. Lipid A analysed using LC-MS. examined an vitro competition assay with flow cytometry. vivo cost evaluated neutropenic mouse thigh infection model. Results Increased observed following B5055. modification lipid phosphoethanolamine addition demonstrated profiling. plasmid revealed instability after acquiring mcr-1. Reduced growth were mcr-1-carrying strain. Conclusions Although confers moderate level resistance, it is associated significant This indicates that mcr-1-mediated could be attenuated limiting usage