The influence of postantibiotic effects and postantibiotic effects of sub-inhibitory concentrations of quinolones and aminoglycosides on phospholipase C of Pseudomonas aeruginosa.

We have studied the postantibiotic effect (PAE) and postantibiotic sub-MICs effect (PA SME) of ciprofloxacin, pefloxacin, netilmicin and tobramycin on the production of phospholipase C (PLC) in a Pseudomonas aeruginosa strain isolated from clinical material. All antibiotics tested (postantibiotic phase evoked by 2.MIC) reduced the production of PLC, particularly pefloxacin to 13.2%. The PA phase evoked by 4.MIC of quinolones did not cause regrowth of P. aeruginosa and aminoglycosides inhibited PLC, in particular with tobramycin to 16.9%. The effect of PA SME (2.MIC) of netilmicin and tobramycin inhibited PLC more expressively (< 20%) than ciprofloxacin; pefloxacin did not allow regrowth. PA SMEs of the antibiotics tested reduced the production of PLC more effectively than PAE.