ABSTRACT
A retrospective multicentric study was carried out over a period of 2 years [1999-2000]. 2659 strains of pseudomonas aeruginosa were collected from 4 university hospitals [charles Nicolle Hospital, pediatric Hospital and national center of Bone Marrow Transplantation in Tunis, Habib Bourguiba Hospital in Sfax]. Epidemiological profile and antibiotic susceptibility were analyesd. All bacteria were identified by conventional methods and antibiotic susceptibility tests were performed according to CA-SFM guidelines. The strains were recovered essrntially from surgical wards [33%] and intensive care units [22%]. Pseudomonas aeruginosa was isolated mainly from pus [36%] urine [32%]and respiratory samples [18%]. 25% of strains were resistant to ticarcilline, 18% to cefsulodine, 9% to ceftazidime, 14% to imipenem and amikacin and 25% to ciprofloxacin. Moreover, the resistance rates varied from hospital to hospital and from unit to another. The resistant strains were isolated particularly from urology and intensive care units: respectively 62% and 39% for ticarcilline; 26% and 13% for ceftazidime. The acquired resistance to b-lactams seems largely due to penicillinase production. The frequency of resistance to ceftazidime was the lowest and seem associated to chromosomal cephalosporinase over production