THE INFLUENCE OF POSTANTIBIOTIC EFFECTS AND POSTANTIBIOTIC EFFECTS OFSUBINHIBITORY CONCENTRATIONS OF OFLOXACIN AND IMIPENEM ON ELASTASE AND PROTEINASE OF PSEUDOMONAS-AERUGINOSA

Suprainhibitory concentrations of ofloxacin and imipenem (2x or 4x MIG ) induced postantibiotic effects (PAEs) against P. aeruginosa of 1.2-4 .9 h. Subinhibitory concentrations of ofloxacin (0.1x, 0.2x and 0.3x M IG) as well as of imipenem (0.1x and 0.2x MIG) added to bacterial. sus pensions in the postantibiotic phase evoked a longer delay of bacteria l regrowth (PA SMEs) as compared to PAEs. Imipenem at 0.3x MIC concent ration added to bacteria previously treated with 2x or 4x MIC of the s ame antibiotic did not allow any regrowth of bacterial culture. PAEs a nd PA SMEs affected the enzymic activity of P. aeruginosa. All combina tions of supra/subinhibitory antibiotic concentrations (except the com bination of 4x MIC + 0.1x MIC of imipenem) reduced more effectively to xic enzymes in comparison with the effect of suprainhibitory concentra tions alone. Elastase activity was suppressed more significantly as co mpared to proteinase.