Role of carriers of Acinetobacter species in transmission of nosocomial infections in intensive care units

Abstract

Background: Acinetobacter baumannii is a common pathogen in intensive care units (ICUs) attended with higher mortality and morbidity, often with its sources and transmission dynamics remaining an enigma. Limited data on carriers of Acinetobacter species necessitated the present study. Objectives: The aim was to determine prevalence of carriers of Acinetobacter spp. And predisposing risk factors among healthy health care workers (HCWs) in ICUs and their role as source in nosocomial infections. Materials and Methods: Specimens from nose, throat, axilla and hands of all HCWs (82, [72 staff nurses and 10 attenders]) from ICUs and 50 (out of 400) from general wards were collected and processed by standard laboratory procedures. Temporal spatial association and Acinetobacter spp. with identical antibiogram type from carriers and cases was done to assess the role of carriers as sources. Fisher's exact test used for statistical analysis. Results: Prevalence of A. baumanii carriers was 14.63% (15.28% vs. 10%, P = 0.55 NS) in nurses and attenders. Higher in female than male HCWs (16.36% vs. 11.11% P = 0.39 NS). Carrier rate was 30% and 28.57% in surgical ICU and neonatal ICU respectively with none from critical care unit, intensive cardiac care unit and general wards. Carrier rate was 4.1% at hands, axilla and throat. Four antibiogram types of A. baumannii from carriers were associated with 46.88% (45/96) of nosocomial infections in ICUs during study period of 6 months. Carrier rate decreased to 4.87% (in repeat samples after 8 weeks) without new infection control practices due to decreasing in the exposure to the pathogen after eight carriers were shifted outside the ICUs for administrative reasons. Conclusions: A. baumanii carriers (HCWs) act as source/reservoirs for nosocomial infections. Constant exposure of HCWs to ICU environment and predisposing risk factors are associated with the acquisition of the carrier state.