MOLECULAR TYPING OF ACINETOBACTER-BAUMANNII ACINETOBACTER-CALCOACETICUS COMPLEX ISOLATES FROM ENDEMIC AND EPIDEMIC NOSOCOMIAL INFECTIONS

Ribotype, biotype and resistance phenotype were used to characterize 3 7 Acinetobacter baumannii-A. calcoaceticus complex isolates responsibl e for nosocomial infections in Buenos Aires. Nineteen isolates were re covered from endemic infections at 2 hospitals and 18 represent an int ensive care unit outbreak that occurred in a third hospital. By riboty ping isolates were classified into five different clones of A. baumann ii biotype 2, 3 of A. baumannii biotype 9, and 3 of Acinetobacter geno species 13. Combination of the three epidemiological markers permitted categorization of 18 outbreak isolates into four probable strains: 2 A. baumannii biotype 2, named type I, and II, and 2 A. baumannii bioty pe 9. Type I (15 isolates) was the most prevalent strain at one hospit al and was responsible for the outbreak. In conclusion, combined analy sis of biotypes, resistance phenotypes, and ribotypes was an accurate approach for epidemiologic investigation of 8. baumannii. Furthermore, ribotyping discriminated Acinetobacter genospecies 13 isolates which were phenotypically difficult to type.