[An Acinetobacter baumanii outbreak at the Versailles Hospital Center]

A. baumannii is a multiresistant bacteria which is recognised as responsible for nosocomial infections and hospital outbreaks. The control of these outbreaks depends on the strain's typing and on the fight's policy against nosocomial infections. An outbreak of A. baumannii is occurred to patients who were hospitalized in Centre Hospitalier de Versailles. To investigate this outbreak, we have determined the biotype (Bouvet's method), the succeptibility pattern (disk diffusion and agar dilution results were analysed with the hierarchical classification and main component analysis) and the total DNA macrorestriction pattern (Pulse Field Gel Electrophoresis using SmaI restriction enzyme). A risk factors for A. baumannii acquisition were delineated in case-control study. During 2 years, 38 patients have been infected or colonized to A. baumannii. Thirty two patients were hospitalized in ICU. We studied 38 non repetitive clinical isolates and 9 strains of the patient's rooms. Four biotypes were defined by the Bouvet's typing method. Fourteen groups were obtained when succeptibility results were analysed with the hierarchical classification and 6 with the main composant analysis. The molecular typing permit us to define 4 epidemic and 6 sporadic strains. All the epidemic strains were isolated on ICU hospitalized patients. Our study has shown wide contamination in patient's rooms (Water tap, dry surfaces, patient's mattresses...). Environmental objects have been a major risk factor for A. baumannii acquisition. The control of this outbreak has been possible by application of hygienic measures (hands washing, isolment, meticulous cleaning of the ICU and environmental controls). No new case is occurred in the last year. Typing methods and case-control study are necessary to investigate cross-infections and take efficient measures against these outbreaks.