[The activity of four fluoroquinolones against strains of Pseudomonas aeruginosa with a different sensitivity pattern to ceftazidime and imipenem]. / Actividad de cuatro fluoroquinolonas frente a cepas de Pseudomonas aeruginosa con diferente patrón de sensibilidad a ceftazidima e imipenem.

OBJECTIVES: To evaluate the activity of four fluorquinolones (ciprofloxacin, clinafloxacin, norfloxacin and perfloxacin) against clinical strains of Pseudomonas aeruginosa with different sensitivity patterns to ceftazidime and imipenem. MATERIAL AND METHODS: 156 strains of isolated P. aeruginosa were studied at the Virgin Macarena University Hospital in Seville during 1998 and 1999. The in vitro activity of four fluorquinolones was determined by microdilution in Mueller Hinton bouillon, supplemented with cations, following the NCCLS guidelines. RESULTS: For all the strains evaluated, the minimum inhibitory concentration values (MIC90) of the clinafloxacin (4 mg/l) were significantly less than those for ciprofloxacin (64 mg/l). In the 76 strains resistant to ciprofloxacin, the clinafloxacin and ciprofloxacin MCI90 were 16 and >128 mg/l respectively. Clinafloxacin was more active than ciprofloxacin, norfloxacin and pefloxacin, independent to the sensitivity pattern or the resistance to ceptazidime and imipenem. CONCLUSION: Clinafloxacin was more active in vitro than ciprofloxacin against P. aeruginosa.