RESUMO
Objective To evaluate the anti-bacteria effects of polymyxin B combined with meropenem against 30 strains pan-drug resistant pseudomonas aeruginosa that separated in clinic. Methods The minimal inhibitory concentration (MICs) of 30 strains pan-drug resistant pseudomonas aeruginosa after treated with polymyxin B and meropenem as single-use or combination use were determined by both microdilution method and checkerboard method. The FIC index was calculated, then the type of combination effect was determined according to FIC index, which was used to determine whether there was synergistic or antagonistic effects. Results The MICs of pan-drug resistant pseudomonas aeruginosa were reduced significantly after polymyxin B combined with meropenem when compared with single-use. The percentages of the FIC index that less than 0.5 and the index between 0.5 and 1 were 60%and 30%respectively. Conclusion The results indicate that the combinations of polymyxin B with meropenem have good synergistic and additive effects against pan-drug resistant pseudomonas aeruginosa, there is no antagonism.