MOLECULAR EPIDEMIOLOGY OF 2 GENES ENCODING 3-N-AMINOGLYCOSIDE ACETYLTRANSFERASES AAC(3)I AND AAC(3)II AMONG GRAM-NEGATIVE BACTERIA FROM A SPANISH HOSPITAL

The molecular epidemiology of the aacC1 and aacC2 genes, encoding 3-N- aminoglycoside acetyltransferases AAC(3)I and AAC(3)II, respectively, was studied by DNA-DNA hybridization. The sample included 315 gentamic in-resistant Gram-negative bacilli collected over a six-month period f rom patients attending a Spanish Hospital. The aminoglycoside resistan ce phenotype of these strains was also determined. The aacC1 probe hyb ridized with 39 strains, the aacC2 probe with 146 strains and both pro bes hybridized with 26 strains. The aacC1 gene was most frequently det ected in Pseudomonas aeruginosa whereas the aacC2 gene was most freque ntly detected in enterobacteria and Acinetobacter spp. Strains harbour ing aacC genes were isolated from both in-and outpatients with differe nt infectious diseases, mainly urinary tract infections. As inferred f rom the results of Southern hybridization, both genes showed a wide ho rizontal dispersion among plasmids and bacteria.