[Study investigating the activity of several fluoroquinolones against Pseudomonas aeruginosa using the mutant prevention concentration].
BACKGROUND
The objective of this study was to compare the activity of ciprofloxacin, levofloxacin, moxifloxacin, gatifloxacin and ofloxacin against Pseudomonas aeruginosa by determining the mutant prevention concentration (MPC).


METHODS
Thirty-four clinical isolates of Pseudomonas aeruginosa causing nosocomial infection were studied. MPC values were determined using an inoculum of 10(10) cfu/mL on Mueller-Hinton plates with serial dilutions of the antibiotics. The microorganisms were classified according to whether the patients had been previously treated with fluoroquinolones or not.


RESULTS
The fluoroquinolone with the lowest MPC values was ciprofloxacin, followed by levofloxacin. Analysis of strains from patients previously treated with fluoroquinolones showed persistent susceptibility according to the CLSI criteria, but with lower activity of all the drugs.


CONCLUSIONS
Although the microorganism remained susceptible to fluoroquinolones according to classical methods, the suitability of using these drugs in patients with severe infection and a history of fluoroquinolone use should be evaluated.
Sirvent
Elia
E
Servicio de Microbiología, Hospital General Universitario de Elche, Universidad Miguel Hernández, Alicante, España.
Ruiz
Montserrat
M
Rodríguez
Juan C
JC
Royo
Gloria
G
D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001372:Aza Compounds / Q000008:administration & dosage / Q000494:pharmacology; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000494:pharmacology; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial / Q000235:genetics; D024841:Fluoroquinolones / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000077734:Gatifloxacin; D005798:Genes, Bacterial / Q000187:drug effects; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D009152:Mutagenicity Tests; D009154:Mutation / Q000187:drug effects*; D015242:Ofloxacin / Q000008:administration & dosage / Q000494:pharmacology; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D011804:Quinolines / Q000008:administration & dosage / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D002939:Ciprofloxacin; D064704:Levofloxacin; D015242:Ofloxacin; D000077734:Gatifloxacin; D000077266:Moxifloxacin