[Inactivation of aminoglycoside antibiotics by clinically isolated Pseudomonas aeruginosa].

Minimal inhibitory concentrations (MIC) of micronomicin (MCR) and gentamicin (GM) against clinically isolated Pseudomonas aeruginosa F 4150 were 1.56 mcg/ml and 6.25 mcg/ml, respectively. Sisomicin, dibekacin, amikacin, netilmicin, tobramycin ribostamycin and kanamycin did not inhibit the strain at the concentrations less than 25 mcg/ml. Each aminoglycoside antibiotic was incubated in Tris-HCl buffer solutions (pH 7.8) containing cell free crude enzyme preparations obtained by sonic oscillation of intact cells of P. aeruginosa F 4150, coenzyme A and adenosine-5'-triphosphate. The residual activity at 3 hours of incubation at 37 degrees C was 88% for MCR and 33.6% for GM, while all of the other aminoglycoside antibiotics tested were completely inactivated under this condition.