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.