Postantibiotic effect of some antibiotics on the metabolism of Pseudomonas aeruginosa.

The influence of the postantibiotic effects (PAEs) of ciprofloxacin, pefloxacin, imipenem, meropenem and amikacin in the suprainhibitory concentrations (2 x and 4 x MIC) on the metabolic processes of P. aeruginosa was studied. The synthesis of macromolecules was expressed by influencing of the incorporation rate of [14C] adenine and [14C] leucine. Remarkable affecting of both biosynthetic processes evoked the suprainhibitory concentration 4 x MIC of meropenem by inhibition of the nucleic acids synthesis to 76.1% and proteins synthesis to 61.1% against the control. The suprainhibitory concentration 4 x MIC of both pefloxacin and ciprofloxacin affected the highest suppression of the endogenous respiration to 16.5% and to 20.3%, respectively. The respiration was influenced the least after the effect of meropenem in the both suprainhibitory concentrations tested. According to our knowledge, this is first report about the evaluation of the endogenous respiration after PAE. In this study we demonstrated the inhibitory effects of 4 x MIC concentration of antibiotics studied on the metabolic processes of P. aeruginosa. The results suggest a multiple mechanism for the PAE.