Over an 18 month period, the bacteriological, clinical and epidemiological characteristics of nosocomial Acinetobacter baumannii infections in a teaching hospital were studied. Typing studies were performed on 38 strains isolated from 36 patients. Twenty-two of the strains were isolated during the three outbreaks.
Surgery, catheterization, mechanical ventilation, and antibiotic therapy for adult patients and respiratory distress syndrome, mechanical ventilation, and prematurity for paediatric patients were the main risk factors identified. All isolates were resistant to penicillins (except ampicillin-sulbactam), cephalosporins, gentamicin, and aztreonam but susceptible to carbapenems and colistin. Resistance to tobramycin, ciprofloxacin, ampicillin-sulbactam, trimethoprim-sulfamethoxazole, and amikacin was variable. Antibiotyping, arbitrarily-primed polymerase chain reaction (AP-PCR) and the pulse-field get electrophoresis (PFGE) indicated the epidemiological relationship. The outbreak strains, demonstrated genetic distinction between our three outbreaks and isolates from specific areas in the hospital. (C) 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved.