Distribution of Acinetobacter species on skin of healthy humans.

The distribution of the 19 currently known genospecies of Acinetobacter on human skin, i.e. forehead, forearm and toe webs, was determined. Three selective media were compared for their specificity for all genospecies of Acinetobacter. A minimal-salts agar supplemented with 1% acetate proved to be more efficient than the Leeds medium for the isolation of most genospecies in mixed culture with other bacterial species. Acinetobacter isolates were provisionally identified using biochemical tests and the DNA transformation assay of Juni. Genospecies identification was performed using amplified ribosomal DNA restriction analysis, and duplicate isolates of the same genospecies from individuals were ruled out by random amplified polymorphic DNA analysis. Over 40% of 192 healthy volunteers carried Acinetobacter spp. at one or more body sites, and the frequencies of colonisation were as follows: forearm (51%), forehead (47%) and toe web (34%). Genospecies 8/9 (Acinetobacter lwoffii) was the most common (61%), followed by genospecies 15BJ and 12 (Acinetobacter radioresistens) at 12.5% and 8%, respectively. The Acinetobacter baumannii-Acinetobacter calcoaceticus group (genospecies 1, 2, 3 and 13TU) that predominates in hospital-acquired infections was found in only one individual.