TABLE 3

Population analysis of four P. aeruginosa strains isolated in 1983 from adult CF patients treated twice daily with 500 mg ciprofloxacin orally a

StrainDayCLSI MIC (mg/liter)Bacterial load determined by population analysis (log10 CFU/ml)
1× CLSI MIC2× CLSI MIC4× CLSI MIC16× CLSI MIC64× CLSI MIC
110.257.66.36.85.5ND
31.0NDND7.37.3ND
52.0NDND4.18.38.8
910.036.66.5NDNDND
31.0ND6.06.75.5ND
51.0NDND6.27.7ND
1910.128.38.68.66.5ND
30.5ND7.57.56.35.9
51.0ND7.37.38.18.3
3610.038.07.26.95.3ND
30.25ND8.37.36.05.9
50.5ND5.56.99.19.3
  • a These isolates were exposed in vitro to fluctuating ciprofloxacin concentrations simulating an oral twice-daily dose of 500 mg. The CLSI MIC was generated by selecting at least three to five well-isolated colonies of the same morphological type for preparation of the inoculum. Population analysis was performed by selecting only one colony for the inoculum preparation (viable counts represent the number of colonies grown on agar plates containing a ciprofloxacin concentration one or two times, etc., the concentration equivalent to the CLSI MIC) (ND, not detected; i.e., viable counts were below the limit of detectability of 2 log10 CFU/ml). See reference 97 for the method used to analyze the data.