In vitro activities of polymyxin B in combination with imipenem gainst pan-drug- resistant strains of Acinetobacter baumannii
Objective To evaluate the in vitro activities of polymyxin B in combination with imipenem against 30 strains of pan-drug resistant Acinetobacter baumannii. Methods The MICs of polymyxin B and imipenem in single-use or in combination against 30 strains of pan-drug resistant Acinetobacter baumannii were determined by broth microdilution method and checkerboard method. The FIC index was calculated according to MIC results. Results The MICs of polymyxin B combined with imipenem were reduced significantly compared with single-use. The percentage of the FIC indexes less than 0.5, between 0.5 and 1 were 50% and 40%. Conclusion The results indicate that the combinations of polymyxin B with imipenem have good synergistic and additive effects against pan-drug resistant Acinetobacter baumannii, there is no antagonism.