Frequency of plasmids in strains of Acinetobacter calcoaceticus.

Plasmids were found in 75 out of 93 clinical isolates of Acinetobacter calcoaceticus. The strains harboured up to 20 plasmids each, with two-thirds containing two or more. Most plasmids were smaller than 15 Md. Strains of A. Iwoffi contained more plasmids than A. anitratus. Plasmid analysis may be an easy and valuable tool in the epidemiology of A. calcoaceticus, especially in conjunction with other typing methods.