Yoğun Bakım Ünitesinde Acinetobacter baumannii Kolonizasyonu ve İnfeksiyonu: Risk Faktörleri, Bulaşma Yolları ve Bulaşma Dinamikleri

Objective: We aimed to evaluate risk factors, transmission routes and dynamics of Acinetobacter baumannii infections and colonization in the intensive care unit (ICU). Methods: This is a prospective cohort study performed in the medical ICU of a university hospital for 4 months. The surveillance cultures were periodically collected from the patients, patients’ beds, tables, pumps, telephones, keyboards and hands of staff, doctors and nurses. Positive cultures indicating A. baumannii colonization were recorded. All isolates were genotyped. Polymerase chain reaction were applied to all of the isolates causing infections in order to detect carbapenemase genes. Results: Fifty nine patients were included. Median length of hospital stay was 15 days and median ICU stay was 11 days. Totally, 1169 samples were collected, 48 (4.1%) of them were colonized with A. baumannii. Colonization and infection rates were 37.2% (22/59) and 13.5% (8/59) and mortality rates of the patients colonized and infected with A. baumannii were 45.5% (10/22) and 25% (2/8), respectively. APACHE II score (hazard ratio, HR: 1.07, 95% confidence interval, CI: 1.02-1.12, p=0.01) and cancer (HR: 4.97, 95% CI: 1.49-16.55, p=0.01) were independent risk factors for mortality. Respiratory failure (HR:2.72, 95% CI.: 1.09-6.80, ρ=0.03) was the only independent risk factor for A. baumannii colonization. Chronic obstructive pulmonary disease (COPD) (HR: 11.57, 95% CI: 1.72-77.88, ρ=0.04) and use of aminoglycosides (HR: 26.92, 95% CI: 2.29-316.62, ρ=0.03) were independent risk factors for A. baumannii infection. Colonization in the patients’ surrounding environment with A. baumannii increased the risk of patients’ colonization (OR:11.56, 95% CI: 1.25-107.07, ρ=0.02). Five different clones were detected among eight isolates of A. baumannii genotyped. All isolates had production of OXA-51 carbapenemase. Conclusions: Risk factors for developing A. baumannii infection and colonization were COPD, use of aminoglycosides, and respiratory failure. Colonization with A. baumannii in the patients' surrounding environment increased the risk of patients’ colonization. However, the effect of A. baumannii infection on mortality was less than expected.