Major Article Control of multidrug-resistant Acinetobacter baumannii in Hong Kong: Role of environmental surveillance in communal areas after a hospital outbreak Vincent C.C. Cheng MD a,b , Shuk-Ching Wong MNurs b,c , Jonathan H.K. Chen PhD a , Simon Y.C. So MMedSc a , Sally C.Y. Wong FRCPath a , Pak-Leung Ho MD a , Kwok-Yung Yuen MD a, * a Department of Microbiology, Queen Mary Hospital, Hong Kong Special Administrative Region, China b Infection Control Team, Queen Mary Hospital, Hong Kong West Cluster, Hong Kong Special Administrative Region, China c Infection Control Team, Tung Wah Hospital, Hong Kong West Cluster, Hong Kong Special Administrative Region, China Key Words: Multidrug-resistant Acinetobacter baumannii Environmental surveillance Outbreak Background: Environmental reservoir is an important source of multidrug-resistant Acinetobacter baumannii (MRAB) outbreaks. The role of postoutbreak environmental surveillance for guiding sustained infection control effort has not been examined. Methods: Enhanced environmental disinfection and regular environmental surveillance of ward com- munal areas after an outbreak were performed in a university-affiliated hospital. To assess the usefulness of environmental culture in predicting patients with MRAB, weekly surveillance of communal areas was continued for 3 months after the outbreak in intervention wards. The incidence of MRAB in interven- tion and nonintervention wards (control) was compared, whereas the other infection control measures remained identical. Results: Postoutbreak weekly surveillance of communal areas showed that identification of newly di- agnosed MRAB patients was significantly correlated with preceding environmental contamination with MRAB (P = .001). The incidence of nosocomial MRAB infection was significantly lower in the interven- tion compared with nonintervention wards (0.55 vs 2.28 per 1,000 patient days, respectively; P = .04). All MRAB isolated from the environmental and patients’ samples belonged to multilocus sequence typing ST457 and were blaOXA23-like positive. Conclusions: Environmental surveillance may serve as a surrogate marker for the presence of MRAB car- riers. Implementation of timely infection control measures should be guided by environmental culture for MRAB to minimize the risk of MRAB outbreak. © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. Acinetobacter baumannii is a medically important gram-negative coccobacillus associated with prolonged nosocomial outbreaks because it is notoriously resistant to desiccation, and can survive on dry surfaces for months. 1 Multidrug-resistant A baumannii (MRAB) has been endemic in health care settings in various parts of the world. 2 Furthermore, environmental contamination by A baumannii with increasing antibiotic resistance has contributed to numerous hospital outbreaks. 3,4 Failure to eradicate the environmental reser- voir has also caused recurrent outbreaks of A baumannii infection in a burn unit, 5 and prior room occupancy with patients carrying MRAB was found to be an independent risk factor for acquisition of MRAB by subsequent patients. 6 Although multifaceted infection control measures, including staff education, promotion of hand hygiene, strict contact precautions with isolation of index cases, environmental cleaning, and tar- geted active surveillance in high-risk areas, have been recommended in the control of hospital-wide transmission of MRAB in endemic situations, disinfection of hospital surfaces was recently found to be a particularly important infection control intervention in outbreaks. 7 Nontouch disinfection technology, such as hydrogen per- oxide vapor decontamination, has been advocated in the eradication of environmental reservoirs of multidrug-resistant gram-negative * Address correspondence to Kwok-Yung Yuen, MD, Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong Special Administrative Region, China. E-mail address: kyyuen@hku.hk (K.-Y. Yuen). Funding/support: Supported by the Health and Medical Research Fund, Food and Health Bureau, Hong Kong SAR Government (no. HKM-15-M12). Conflicts of interest: None to report. ARTICLE IN PRESS 0196-6553/© 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajic.2017.07.010 American Journal of Infection Control ■■ (2017) ■■-■■ Contents lists available at ScienceDirect American Journal of Infection Control journal homepage: www.ajicjournal.org American Journal of Infection Control