RESUMEN
Aim To investigate the antibacterial activity and anti-resistant mutation ability of Qiguiyin decoction (a traditional Chinese herbal formula) combined with levofloxacin against pseudomonas aeruginosa byantibacterial experiment in vitro and serum pharmacology. Methods The minimal inhibitory concentrations (MICs) of levofloxacin and Qiguiyin decoction were detected respectively by the broth dilution technique.The MIC of the combination of two drugs was determined by the micro chessboard dilution method. The effects of combined drugs on enhancing the antibacterial activity of different strains were evaluated respectively by calculating the fractional inhibitory concentration index (FICI). The drug-containing serum of levofloxa-cin group, Qiguiyin decoction group, Qiguiyin decoction combined with levofloxacin group and control group was prepared. The antibacterial rate, MIC and MBC of 10% ~ 90% serum against the two strains were determined. Results Combined with Qiguiyin decoction, MIC of levofloxacin against pseudomonas aeruginosa (standard/resistant) decreased significantly, 0. 5 < FICI