Background: Our ICU has witnessed a gradual increase in infections due to Acinetobacter baumannii complex that has reached a level of stable endemia since 1995. This situation, aggravated by a high degree of resistance, has led to the present prospective study, designed to establish the incidence of Acinetobacter colonization and to investigate the role of risk factors and their relation to environmental colonization.
Methods: Serial sampling of all patients from the time of ICU admission to discharge. Sample collection from the environment and from hospital personnel. Monitorization of pre-established risk factors and detection of episodes of infection.
Results: One-third of patients were colonized during their stay, with the trachea (43%), rectum (31%), and skin (35%) being the most frequent sites. In 92% of cases, colonization was established within the first 9 days after admission. Significant risk factors included mechanical ventilation (p < 0.01) and previous use of antibiotics (p < 0.007). Acinetobacter was recovered from thermometers (35%), respirator switches (43%), and damp surfaces (54%). Infection developed in 8% of patients; all had been previously colonized.
Conclusions: In an endemic setting, Acinetobacter colonization can occur in a third of ICU patients. This event is relatively early and often precedes infection. Duration of mechanical ventilation and previous use of antibiotics are the main risk factors. Environmental elements are frequent bacterial reservoirs, but the main reservoir is the colonized patient.