DIFFERENTIATION OF ACINETOBACTER-BAUMANNII BIOTYPES BY AMPLIFICATION OF 16S-23S RIBOSOMAL-RNA INTERGENIC SPACER SEQUENCES

Isolates of Acinetobacter baumannii (32 strains) from blood samples ob tained from patients in five Chilean hospitals were identified and bio typed according to their phenotypic properties. They were also submitt ed to random amplified polymorphic DNA (RAPD) using eight randomly des igned 10-mers and the core sequence of M13 phage (15-mers) as well as amplification of the spacer regions between 16S and 23S genes in the p rokaryotic rRNA genetic loci. With some primers, RAPD discriminated be tween biotypes, whereas with others each isolate showed a particular p rofile. When amplification of spacer regions was performed, a clear co rrelation between patterns and biotypes was found. This last technique allowed correct biotyping of clinical isolates. Both genetic methods might be used for the identification of A. baumannii biotypes.