BIOFILM FORMATION BY ACINETOBACTER-BAUMANNII

Acinetobacter baumannii, an important nosocomial pathogen is usually f ound on various surfaces in the hospital environment. In this work, th e ability to form biofilms on the surface of sterile coverslips by one clinical isolate of A. baumannii was studied. Sessile cells which adh ered to coverslips after being immersed in a nutrient-deficient minera l medium were observed by epifluorescence and scanning electron micros copy at various times of incubation. A rapid increase in the number of sessile cells in young biofilms, followed by a slower increase of suc h cells was found. At 48 h biofilms were clearly visible and an amorph ous material similar to the exopolysaccharide described in some other bacteria covered sessile cells was evident. Biofilm formation by A. ba umannii probably favours its maintenance on solid surfaces in the hosp ital environment and protects the micro-organism against some antibact erial factors.