In Vitro Activity of Eravacycline in Combination with Colistin Against Carbapenem-Resistant A. baumannii Isolates

The synergistic activity of eravacycline in combination with colistin on carbapenem-resistant A.baumannii (CRAB) isolates was evaluated in this study. Minimum inhibitory concentrations (MICs) of eravacycline and colistin were determined by the broth microdilution method. MICs values ranged between 1 to 4 mg and 0,5 to 128 mg/L for eravacycline and colistin, respectively. In-vitro synergy between eravacycline and colistin was evaluated by using the chequerboard methodology. Synergistic (10 %) and additive ( 20 %) effects were detected. Antagonism was not detected.  Similar activity is maintained in colistin resistant CRAB isolates. The result of this study indicates that eravacycline and colistin combination may be a potential therapeutic option for the treatment of carbapenem-resistant A.baumannii  related infections.