A. baumanii is recognised by his nosocomial character. Our study was justified by several aspects : the increase in the isolation of the strains these three last years, their multiresistance to antibiotics which becomes usual, the exposed patients who are immunocompromised and finally, epidemic character of the infections.

This study related to 499 strains of A. baumanii isolated from 65 852 pathological specimens in 3 years (2001–2003). The identification was made using the morphology (Gram) and biochemical characters: negative oxidase and rapid identification (Api GN - biorad). The antibiogram was carried out according to CA-SFM standards and the interpretation was done by the software ‘SIR-i2a’. The strains supposed at the origin of epidemics were analysed by AP-PCR after extraction of their DNA by the kit ‘QIAmp DNA minikit-Quiagen’.

A. baumanii was isolated with a prevalence from 0.75% primarily from blood, punctures and katheters, especially in the medical intensive care and surgery units. Concerning b-lactams, 70% of the strains had a penicillinase and a cephalosporinase, concerning in particular, ceftazidim, cefsulodin, cefepim and tazobactam. A low sensitivity or a resistance to imipenem was noted in 40% of cases, to fluoroquinolones in 80% and to cotrimoxazole in 51%, to phosphomycin in 60% of cases. Concerning aminosides, we noted the phenotype KGA in 38% of cases, KGTA in 20%. A sensitivity to colistin was noted in 100% of cases. Two epidemics were noted with the medical intensive care unit (in September 2002 and from September to November 2003).

All these data show that A. baumanii gives a problem with surgery and intensive care units in our hospital, with possibilities of antibiotic treatment often limited to imipenem and tobramycin. The epidemic strains were often most resistant to antibiotics.