The magnitude of this fitness cost is an important biological parameter that influences the degree to which antibiotic resistant strains become widespread. We quantified the fitness cost of resistant strains obtained by experimental evolution in the presence of various antibiotics, the relationship between the fitness cost of antibiotic resistance cost and comprehensive phenotypic and genotypic changes remains unclear. And analyzed how the cost correlated to phenotypic and genotypic changes in the resistant strains.
We found that the decrease of the specific growth rate was correlated with overall expression changes between the parent and resistant strains; results: we measured the specific growth rate of the resistant strains in the presence of various concentrations of drugs or in their absence. We also found that there are a number of genes whose changes in expression levels were significantly correlated with the growth rate; measured by the Euclid distance between expression profiles. European Photochemistry Association, which may account for the observed correlation between the fitness cost and overall expression changes.