Nosocomial imipenem-resistant Acinetobacter baumannii infections in intensive care units: incidence and risk factors assessment

Abstract

Imipenem-resistant Acinetobacter baumannii (A. baumannii) (IRAB) has emerged as a challenging nosocomial pathogen particularly in intensive care units (ICUs). Studying the risk factors associated with IRAB infection is of paramount importance for appropriate control of IRAB spread. The aim of this study was to assess the incidence rate and possible risk factors associated with nosocomial IRAB infections in ICUs. A prospective cohort study was carried out in surgical and emergency ICUs of a tertiary care hospital in Egypt. All patients who developed nosocomial A. baumannii infection from the start of January 2014 to the end of December 2015 were included. Isolates were identified as A. baumannii using API 20NE and E-test was used to define IRAB. Out of 146 A. baumannii isolates, 11 were found to be IRAB (7.5% incidence rate), of them 72.7% (8/11) were found to be multidrug resistant (MDR). Univariate analysis demonstrated that hospital stay before ICU admission [Relative risk (RR) 3.51, 95% confidence interval (CI) 1.0- 12.7, P= 0.04)], longer ICU stay (P= 0.005), exposure to emergent surgery (RR 17.5, CI 7.39-41.4, P= 0.000), the presence of central venous catheter (RR 3.26, CI 1.0-10.6, P= 0.04) and previous carbapenem use (RR 4.05, CI 1.12-14.6, P =0.02) were significant risk factors for IRAB infection. In conclusion, a relatively high IRAB incidence was recorded in ICUs of our hospital. Hospital stay before ICU admission, longer ICU stay, exposure to emergent surgery, the presence of central venous catheter and previous carbapenem use were significant risk factors for IRAB infection. Rationale use of carbapenems in ICUs should be considered.

Keywords: Imipenem-resistant, Acinetobacter baumannii, Intensive care units