Multidrug and carbapenem-resistant Acinetobacter baumannii infections: Factors associated with mortality

Abstract

Background and objective: To analyse factors related to mortality and influence of antibiotic treatment on outcome in patients with nosocomial infection due to multidrug and carbapenem-resistant Acinetobacter baumannii (MDR-C AB).

Patients and methods: Observational and prospective study of a cohort of adult patients with MDR-C AB infection. Data collection from clinical records was done according to a standard protocol (January 2007 through June 2008). Patients with MDR-C AB infection were identified by review of results of microbiology cultures from the hospital microbiology laboratory. Epidemiological and clinical variables and predictors of mortality were analysed.

Results: 24 out of 101 cases were considered colonizations and 77 infections (27 bacteraemia); global mortality in infected patients was 49% (18 cases with bacteraemia and 20 with no bacteraemia). In the multivariate analysis, including the 77 cases of infection, the prognosis factors associated with mortality were age (OR 1.09; 95% CI 1.02-1.2), McCabe 1 (OR 33.98; 95% CI 4.33-266.85), bacteraemia (OR 9.89; 95% CI 1.13-86.13), inadequate empiric treatment (OR 16.7; 95% CI 2.15-129.79), and inadequate definitive treatment (OR 26.29; 95% CI 1.45-478.19). In the multivariate analysis including the 57 cases of infection with adequate definitive treatment, the prognosis factors associated with mortality were McCabe 1 (OR 24.08; 95% CI 3.67-157.96) and monotherapy versus combined treatment (OR 7.11; 95% CI 1.63-30.99).

Conclusions: Our cohort of patients with MDR-C AB infection is characterised by a very high mortality (49%); the severity of patients and inadequate treatment or monotherapy are statistically associated with mortality.