Clinical outcomes of patients infected with carbapenem-resistant Acinetobacter baumannii treated with single or combination antibiotic therapy

Abstract

Objective: To evaluate treatment outcomes in patients with carbapenem-resistant Acinetobacter baumannii (CRAB) nosocomial infections treated with antimicrobial agent either alone or in combination.

Material and method: Clinical data were retrospectively evaluated in patients with CRAB nosocomial infections admitted to Songklanagarind Hospital, Songkhla, Thailand from January-December 2008.

Results: One hundred ten patients with CRAB nosocomial infections were identified. Most patients (57.3%) had site of infection in the lower respiratory tract and the majority of them (61.8%) received a single antimicrobial agent. Crude mortality was 30%. The presumptive success rate was 60.3% (41/68) for patients given monotherapy and 81.0% (34/42) for patients given combination therapy (p = 0.024). Patients given combination therapy were more likely to have been given at least one antibiotic to which the organism was susceptible (p = 0.004). In multivariate analysis, renal impairment, bloodstream infection, and inappropriate antimicrobial regimen were independent predictors of treatment failure.

Conclusion: The combination therapy regimen yielded more presumptive treatment success by increasing the likelihood of an appropriate antimicrobial therapy. Additionally, inappropriate antimicrobial treatment, renal impairment, and bloodstream infection were associated with poor treatment outcomes in patients with CRAB nosocomial infections.