Aminoglycoside resistance patterns in clinical isolates of Enterobacteriaceae from Czechoslovakia

Multi-resistant Enterobacteriaceae isolated mainly from urine specimens from patients at the Department of Urology, Kramáre Hospital, Bratislava, were characterized for resistance phenotype. Seventeen gentamicin-resistant isolates were further studied for the presence of aminoglycoside-modifying enzymes. Five enzymes were detected: AAC(2'), AAC(3)-II, AAC non-characterized, ANT(2") and APH(3')-I. The substrate range of these enzymes was found to correlate with the resistance phenotype in most isolates. In our collection the AAC(3)-II enzyme that inactivates gentamicin, sisomicin, tobramycin and netilmicin was predominant. Predominance of this type of modifying enzyme has been observed also in resistant Gram-negative strains in Belgium, The Netherlands and Chile, in contrast to the United States, Federal Republic of Germany, Switzerland, Greece and Turkey, where ANT(2") has been the most common enzyme.