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

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).

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.

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).

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.