Control of multidrug-resistant Acinetobacter baumannii in Hong Kong: Role of environmental surveillance in communal areas after a hospital 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 communal 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 intervention 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 diagnosed MRAB patients was significantly correlated with preceding environmental contamination with MRAB (P =.001). The incidence of nosocomial MRAB infection was significantly lower in the intervention 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 carriers. Implementation of timely infection control measures should be guided by environmental culture for MRAB to minimize the risk of MRAB outbreak.