[Evolution of Acinetobacter calcoaceticus in the hospital milieu, from 1971 to 1984].

During the last 10 years the authors have evaluated the increasing part played by Acinetobacter calcoaceticus in nosocomial infections and the increasing resistance of this species to antibiotics. The study involved 850 clinical strains isolated from 1971 to 1984, and 24 antibiotics were tested. A progressive increase in resistance to beta-lactam antibiotics, aminoglycosides and tetracycline was observed, and to date up to 80-90% of the strains are resistant to all but major drugs such as imipenem, ceftazidime, tobramycin and amikacin. A significant difference in susceptibility to the major antibiotics was noticed between Acinetobacter clinical strains isolated before and after 1980. A correlation study between the development of resistant strains and the hospital consumption of antibiotics showed that this was a factor to be taken into account. After the new Bichat Hospital was opened, in 1980, the rate at which var. anitratum strains were isolated rose from 77.5% to 94.5%. The opening of new departments (intensive care units) with a higher risk of infection and a totally different environment probably constitutes the most important factor in this evolution.