Genotypic and phenotypic similarity of multiresistant Acinetobacter baumannii isolates in the Czech Republic

The diversity of 103 clinical isolates of the Acinetobacter calcoaceticus-A cinetobacter baumannii complex obtained between 1991 and 1997 from 17 Czech hospitals was studied by ribotyping, biotyping, plasmid profiling and anti biotic susceptibility testing. According to the EcoRI ribotypes, all but on e of these isolates were identified to the DNA group level: 77 isolates wer e allocated to DNA group 2 (A, baumannii), 14 to DNA group 3, 10 to DNA gro up 13 sensu Tjernberg and Ursing and one to DNA group 1 (A, calcoaceticus). In total, 50 different EcoRI ribotypes and 10 biotypes were observed, Plas mids were found in 92% of the isolates and a high variability in plasmid pr ofiles was found in isolates of the same DNA group. The combination of typi ng profiles allowed two predominant groups (termed A and B) to be distingui shed among the A. baumannii isolates (37 and eight isolates, respectively) that shared a specific ribotype and were highly similar in other properties . These two groups comprised both sporadic and outbreak isolates and were f ound in most localities. Group A and B isolates were markedly more resistan t to antibiotics than most of the remaining isolates, thus representing 85% of all multiresistant isolates. The features of groups A and B corresponde d to those of two epidemic clones identified recently among hospital strain s in north-western Europe.