BACTERIOLOGICAL STUDY OF A SINGLE DAILY D OSE OF ONCE-DAILY AMIKACIN IN CYSTIC-FIBROSIS PATIENTS WITH PSEUDOMONAS-AERUGINOSA EXACERBATIONS

The interest of the treatment with a single daily dose of amikacine (A MK) in cystic fibrosis (CF) patients with P. aeruginosa infections has been much debated. The aim of work was to study the efficiency of thi s treatment on (CF) patients with chronic bronchopulmonary P. aerugino sa infections previously treated for two weeks with the combination ce ftazidime (CAZ 200 mg/day in 3 inj. IVD) and AMK (35 mg/day in one IV perf. of 30 minutes). The bacteriological supervision of this treatmen t was performed 1 : by the determination of MICs before and after trea tment, 2 : by the decrease of P. aeruginosa colonization immediately a fter this treatment and during 11 months, 3 : by the identification of P. aeruginosa strains with phenotypic methods (serotyping and antibio typing) and with genotypic method (pulsed field gel electrophoresis). The use of AMK in a single daily dose in order to treat chronic lung i nfections colonized with P. aeruginosa susceptible to this antibiotic shows encouraging results as far as bacteriology is concerned : this t reatment has given means to reduce colonization for a month in 15 of 1 8 patients. For 9 of the 18 patients, no P. aeruginosa strains were is olated for nine months. The serotyping and antibiotyping systems do no t enable us to study the P. aeruginosa epidemiology. Genome macrorestr iction fingerprinting of P. aeruginosa in pulsed field gel electrophor esis confirms that patient with CF were colonized with one or several clones. In our study no variation of these clones was noticed for the first eleven months. Genome macrorestriction fingerprinting appears to be one of the most effective methods for delineate strains of P. aeru ginosa colonizing CF patients.