Biotyping of Acinetobacter calcoaceticus using the API 2ONE system.

The API 2ONE system for the identification of non-fermentative Gram-negative bacilli enables the discrimination of a possible 209 different biotypes of Acinetobacter spp. and consequently has potential for use as an Acinetobacter spp. typing system. A total of 122 separate strains of Acinetobacter spp. isolated in Nottingham hospitals over a 4 year period from a wide variety of clinical specimens, divided into 31 different biotypes which were stable over a 1 year storage period. Two biotypes predominated, one of which was a multiply resistant strain of A. calcoaceticus variant anitratus. The API 2ONE system was found to be a rapid method for biotyping strains of Acinetobacter spp. and was helpful in monitoring cross-infection and spread of particular strains of Acinetobacter spp. in the hospital environment.