In vivo activity of levofloxacin alone or in combination with imipenem or amikacin in a mouse model of Acinetobacter baumannii pneumonia

We evaluated the in vivo activity of levofloxacin alone or in combination w ith imipenem or amikacin in a mouse model of Acinetobacter baumannii pneumo nia using a susceptible strain and one with low-level resistance (MIC/MBC o f levofloxacin: 0.06/0.06 and 4/4 mg/L, respectively), As demonstrated prev iously with other pathogens, the AUC/MIC ratio predicted the efficacy of fl uoroquinolones against A. baumannii. This parameter correlated with bacteri cidal effect and survival. Combination therapy did not enhance the efficacy of levofloxacin.