PHARMACODYNAMIC PARAMETERS OF AMINOGLYCOSIDES AND THEIR EFFECT ON EXOENZYMES OF PSEUDOMONAS-AERUGINOSA

Aminoglycosides at 2x or 4x minimum inhibitory concentration induced p ostantibiotic effects against Pseudomonas aeruginosa lasting 3.5-4.9 h (gentamicin) and 0.5-3.7 h (selemycin). Postantibiotic effects of sub inhibitory concentrations of the aminoglycosides tested were substanti ally longer. Some combinations of supra- and subinhibitory concentrati ons of antibiotics did not even allow any regrowth of the bacterial st rain. The postantibiotic effects and postantibiotic effects of subinhi bitory concentrations of gentamicin and selemycin were associated with changes of P. aeruginosa elastase and proteinase. Combinations of sup ra- and subinhibitory concentrations more pronouncedly suppressed enzy mic activities than did suprainhibitory concentrations alone.