Acinetobacter baumannii is a feared pathogen in the burn center due to its opportunistic nature and its multidrug resistance. Our purpose was to study the incidence density of Acinetobacter baumannii colonization and infection and to determine the antibiotic susceptibility of the strains isolated in patients hospitalized in the Trauma and Burn Center Burn Unit in Tunisia. Our retrospective study included 1517 non-repetitive strains of Acinetobacter baumannii, between January 2012 and September 2020, with an average rate of 12.2% of the service's bacterial ecology. The incidence density of Acinetobacter baumannii colonization and infection was 13.7‰ days of in-patient stay and 14.1‰ days of in-patient stay, respectively. A positive and statistically significant correlation between Acinetobacter baumannii colonization and infection (rs=0,7; p=0.005) was noted in our study. The colonization strains were mainly isolated from central catheters (71.2%) and skin swab samples (22.9%). Infections were dominated by bacteremia (47.6%) and respiratory tract infections (25.4%). Bacteremia was microbiologically documented in 53% of cases. The most common source of bacteremia was central catheters (60.8%), skin (22.2%) and respiratory tract (15.5%). The rates of resistance inAcinetobacter baumannii to the antimicrobial agents tested were high: ceftazidime (85.2%), pipéracillin-tazobactam (95.6%), imipenem (95.3%), amikacine (91.1%), ciprofloxacin (93.5%), rifampicin (36.4%) and cotrimoxazole (88.1%). The resistance of colistin was noted in 1.8% of cases.