Acinetobacter baumannii infection in a medical intensive care unit: The impact of strict infection control

Abstract

Background. Acinetobacter baumannii is a waterborne organism that preferentially colonises aquatic environments. Infections usually involve organ systems that have a high fluid content. Multidrug-resistant (MDR) A. baumannii is recognised to be among the most difficult antimicrobial-resistant Gram-negative bacilli to prevent and treat in the nosocomial setting. Objective. To determine the utility of concomitant implementation of a strict antimicrobial stewardship programme and comprehensive infection control measures to control MDR A. baumannii in a medical intensive care unit (ICU). Methods. We retrospectively compared the relative incidence of A. baumannii infections in our unit over a 1-year period before (2012) and after (2016) the implementation of strict infection control bundles. Patients with A. baumannii infections were identified using the microbiology database of the National Health Laboratory Service’s central data warehouse. The total number of admissions and clinical data were derived from the ICU registry. Results. A. baumannii was isolated from 43/263 patients (16.35%) in 2012 compared with 37/348 patients in 2016 (10.63%, p=0.03; relative risk reduction=35%). We found almost 100% sensitivity to colistin and tigecycline, but 90% resistance to carbapenem antibiotics. Conclusion. The introduction of strict infection control bundles had a statistically significant and clinically meaningful impact on the incidence of nosocomial A. baumannii infection in the medical ICU.