Fitness Cost of Daptomycin-Resistant Staphylococcus aureus Obtained from in Vitro Daptomycin Selection Pressure.

ABSTRACT: Daptomycin-resistant (DAP-R) Staphylococcus aureus strains are well documented, but have not been reported in China. To elucidate the evolution adaptability and fitness cost of DAP-R S. aureus, three DAP susceptible strains, Pre3 (MRSA, ST239-t037), Pre5 (MRSA, ST239-t037), and Pre14b (MSSA, ST188-t189), were isolated from patients with bloodstream infections, and serially passaged in Mueller-Hinton broth with a gradient of DAP concentration to select for resistance. Highly DAP-R mutants were obtained after screening for 34 passages. The DAP minimum inhibitory concentrations increased from 0.5 μg/ml in the parent strains to 16 μg/ml in the mutants, which remained tolerant to 4 μg/ml of DAP for more than 160 generations. The growth of the three mutant strains was slower than t

SUBMITTER: Li S 

PROVIDER: S-EPMC5684181 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature