[The propagation of aminoglycoside transferases in gram negative bacteria]

Molecular genetic and enzymatic studies on Gram-negative bacteria from hospital specimens give the following picture on surveillance of aminoglycoside transferases: The most frequent enzymes inactivate streptomycin only, AAD- (3'') and APH-(3''). Only 15% of the isolated enzymes inactivate gentamycin, tobramycin, sisomycin or amikacin. The most frequent of these are AAD-(2'') with 7% and AAC-(6') IV with 3%, both enzymes inactivate a wide range of substrates. The high frequency of streptomycin inactivating enzymes is due to the high incidence of linked resistance markers. A plasmid rPB1 is described, that is present in about 10% of all clinical isolates of E. coli. It has a molecular weight of 4. 1 Mdal and typical restriction pattern.