Aminoglycoside resistance. Enzymatic mechanisms in clinical bacterial strains in Slovakia during the last decade.

We determined the importance and dissemination of enzymatic mechanisms of aminoglycoside resistance in 239 gentamicin-resistant strains of Gram-negative bacilli isolated in Slovakia during the past decade. Over the past 5 years, the resistance to tobramycin has risen by 1.1% to netilmicin by 27.4%, to amikacin by 78.3%, and resistance to isepamicin was high too (81.9%). Sixteen different aminoglycoside-modifying enzymes were detected and their significance for resistance to aminoglycosides was confirmed. It is evident that within the past 5 years gentamicin-resistant bacterial have obtained genetic information on resistance to the other aminoglycosides tested and the percentage of strains with different enzyme combinations has risen. These observations confirm the continuously increasing complexity of antibiotic resistance in clinical bacterial isolates under study in Slovakia during the last decade.