Abstract: Aim To study the in-vitro postantibiotic effec1s (PAEs) induced by Gentamicin (GN), Netilmicin (NTL) and Amikacin (AMK) and estimate their clinical significance. Methods The invitro postantibiotic effects (PAE) induced by GN, NTL and AMK were determined by means of measurement of transmitance using AV ANGE Microbilolgy system. Results The PAE induced by GN、NTL and AMK against gram-postive and gram-negative bacterial was rather long,and even in the subinhibitory antibiotic concentrations (sub-MICs). The duration of the PAE was enhanced with increasing concentration, showing strongly a concentration-dependent relationship (P<0.05),Furthermore,the PAE induced by different pathogens was varied. Conclusion Less fre-quences and longer dosing intervals in adminstration of aminoglycosides would be able to maintain the same efficiency and to reduce the side effects.

Key words: The postantibiotic effect, Gentamicin, Netilmicin, Amikacin, Spectrometer methods