In vitro antibacterial activity of colistin in combination with other antibacterials against the 73 strains of multidrug-resistant acinetobacter baumannii / 中国药学杂志

ABSTRACT

OBJECTIVE: To evaluate the antibiotic effects in vitro of colistin combined with other antibacterials respectively against 73 strains of multidrug-resistant Acinetobacter baumannii (MDR-Ab). METHODS: The protocol was designed by checkerboard method and the MICs of drugs alone and combination against the 73 strains of Acinetobacter baumannii were determined by broth dilution method, the FIC index was calculated according to MIC results. The interaction was measured by the fractional inhibitory concentration index (FIC) antagonism was defined as FICI≥4, indifference as 1RESULTS: Combined colistin and minocycline showed 6.85% synergism, 61.64% partially synergism, 31.55% additivity, no indifference, and antagonistic effect on MDR-AB strains. Combined colistin and fosfomycin demonstrated 15.07% synergism, 47.95% partially synergism, 32.88% additivity, 4.11% indifference, and no antagonistic effect on MDR-AB strains.

CONCLUSION:

The results suggested that synergism and partially synergism and addition of colistin combined with minocycline and fosfomycin respectively against 73 strains of Acinetobacter baumannii were main action, there are little indifference and no antagonism.