Molecular epidemiology of carbapenem-resistant acinetobacter baumanniiin patients and their surrounding environment

Abstract

Background

There has been an increasing awareness of the role of the hospital environment as a reservoir of Acinetobacter baumannii. A. baumannii is an important nosocomial pathogen and is difficult to control due to the increasing cases of resistance to carbapenem.

Objectives

The objectives of this study areto examine carbapenem-resistant Acinetobacter baumannii (CRAB) positive patients according to their environmental sample to determine how frequently the environment surrounding the patient becomes contaminated and which environmental surfaces are most commonly contaminated.

Methodology

During June 2011 to December 2011, data regarding 30 hospitalized patients with at least one positive CRAB clinical sample were collected from hospital X in Kowloon of Hong Kong. For 30 case patients, one patient in the ICU ward had been isolated in a single room and the other 29 patients stayed in a multi-room. Fifteen surfaces in the patient cubicle and nine surfaces in health care worker stations were evaluated for the presence of CRAB. 29 control environmental samples were obtained from the surroundings of patients without CRAB in the same cubicle and one control environmental sample was obtained from the surroundings of patients without CRAB in the other room of ICU. Pulsed-field gel electrophoresis was performed on all environmental isolates and clinical samples.

Results

Of the 30casepatients, 26 patients (86.7%) were found to have CRAB contamination in their surrounding environment and 6negative control patients (20%) were found to have CRAB in their environmental samples. The percentage of positive CRAB cultures in the case environment, control and health care worker stations was 28.9% (117/405), 3.4% (14/406) and 1.9% (5/265)respectively. In the surrounding case patient area, pillows (60% 18/30) and bed sheets on which the patients sleep on (60% 18/30), bed sheets covering the patients (50% 15/30) and bedside table tops (40% 12/30) were the most commonly contaminated. For 26casepatientswere found to have CRAB contamination in their surrounding environment, 23 (88.5%) of these patients were found to have the clone of isolates in the case environment related to the patients.

Conclusion

For patients with CRAB, the surrounding environment is frequently contaminated.

Surfaces often touched by the patients are commonly contaminated. CRAB was also found on surfaces that were not closely related to the patient which are frequently touched by healthcare workers during patient care.