Sulbactam efficacy in experimental models caused by susceptible and intermediate Acinetobacter baumannii strains

Sulbactam and imipenem were compared in an experimental pneumonia model in immunocompetent mice, using a susceptible strain of Acinetobacter baumannii , and in an experimental endocarditis model in rabbits, using an intermedia tely susceptible strain. In the former, sulbactam was as efficacious as imi penem in terms of survival, sterility of lungs and in the bacterial clearan ce from lungs and blood, provided that the t > MIC for sulbactam (1.84 h) w as similar to that for imipenem (2.01 h). In the endocarditis model, imipen em (t > MIC, 2.12 h) was more efficacious than sulbactam (t > MIC, 1.17 h) in bacterial clearance from vegetations. These results show the efficacy of sulbactam in infections caused by susceptible strains of A. baumannii, wit h an MIC up to 4 mg/L, provided that doses reach a t > MIC similar to that of imipenem. The activity of sulbactam was time dependent.