RESISTANCE TO FLUOROQUINOLONES IN PSEUDOMONAS-AERUGINOSA AND KLEBSIELLA-PNEUMONIAE

The fluoroquinolone sensitivity of Pseudomonas aeruginosa and Klebsiel la pneumoniae was studied by determinations of Minimum Inhibitory Conc entrations (MICs) of norfloxacin and ciprofloxacin in consecutive clin ical isolates. In P. aeruginosa, resistance or reduced susceptibility (MIC greater than or equal to 8 mg/l for norfloxacin and greater than or equal to 2 mg/l for ciprofloxacin) was found in 17% (9/54) of the i solates. Reduced susceptibility (MIC greater than or equal to 2 mg/l f or norfloxacin) was found in 12% (10/84) of K. pneumoniae isolates. P. aeruginosa strains isolated in 1991 had reduced susceptibility to bot h norfloxacin and ciprofloxacin significantly more often than isolates from 1984-85 (p = 0.02). 10/84 K. pneumoniae strains from 1991 had re duced susceptibility to norfloxacin, compared with 1/34 from 1984-85. This difference was not statistically significant (p = 0.11).