[Carbapenem and multidrug-resistant Acinetobacter baumannii colonisation/infection: epidemiology and factors associated with infection]

Abstract

Background and objective: To study an outbreak of nosocomial colonisation/infection due to multidrug and carbapenem resistant A. baumannii (ABMDR-C).

Patients and methods: Prospective study of patients with ABMDR-C colonisation/infection (January 2007-June 2008). Epidemiological and clinical variables and predictors of infection versus colonization were analysed.

Results: 24 out of 101 cases were considered colonisations and 77 infections (27 bacteraemia); global mortality (colonisations and infections) was 42% (4 colonisations and 38 infections -18 bacteraemia). All together, the incidence was 3.2/1000 admissions/day; 29% had been previously admitted and 79% had received previous antibiotic treatment (29% carbapenem; 34% piperacillin-tazobactam; 12.5% both); 78% had an underlying condition; 81% were UCI patients; 90% had gone through invasive procedures; 65% had another microorganism isolated. In multivariate analysis, infection predictor factors were isolation of ABMDR-C in respiratory samples (OR 5.406; 95% CI 1.419-20.599); male patients (OR 8.842; 95% CI 1.988-39.325); previous hospitalization (OR 9.720; 95% CI 1.383-68.291) and initial clinical severity (OR 30.897; 95% CI 5.533-172.543).

Conclusions: Our cohort of patients with ABMDR-C colonisation/infection is characterised by their underlying comorbidity, the high rate of previous invasive procedures, previous hospitalisation and previous broad-spectrum betalactam treatments (especially carbapenem). Initial severity and respiratory samples with ABMDR-C isolates were predictors of infection versus colonisation.