Correlation of aminoglycoside resistance with the KmS and Vmax/Km ratios of enzymatic modification of aminoglycosides by 2''-O-nucleotidyltransferase.
A clinical isolate, Serratia marcescens 75, was found to be susceptible to netilmicin and yet had a high level of aminoglycoside 2''-O-nucleotidyltransferase activity for netilmicin. Kinetic studies of the partially purified enzyme revealed substrate inhibition for gentamicin and tobramycin at concentrations greater than 10(-2) mM, but this was not observed for netilmicin. The MICs of the aminoglycosides tested exhibited a good inverse correlation with the Km values for the enzyme and a direct correlation with the Vmax/Km ratios of the enzyme.
DeHertogh
D A
DA
Lerner
S A
SA
D000617:Aminoglycosides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D005839:Gentamicins / Q000378:metabolism; D007700:Kinetics; D009428:Netilmicin / Q000494:pharmacology; D009713:Nucleotidyltransferases / Q000378:metabolism*; D012706:Serratia marcescens / Q000201:enzymology*; D014031:Tobramycin / Q000378:metabolism; D014465:Ultrasonics
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D009428:Netilmicin; D009713:Nucleotidyltransferases; C020565:gentamicin 2''-nucleotidyltransferase; D014031:Tobramycin