Antibiotic disk diffusion test and quantification of the resistant mutant subpopulations of the 38 P. aeruginosa CF isolates.

aMRS genes was considered positive (+) when the sequences of mutS and mutL genes were wild type and negative (−) when were mutated.DD, diffusion diameter zone; RMS, resistant mutant subpopulation: +100 mutants.Zone diameter interpretative criteria was according to CLSI: S, susceptible; I, intermediate resistance; R, resistant.*lack of diffusion zone that prevents the resistant mutant subpopulation to be quantified.