Extensively drug-resistant Acinetobacter baumannii outbreak cross-transmitted in an intensive care unit and respiratory intensive care unit.

Background: Extensively drug-resistant Acinetobacter baumannii (XDRAB) is a great threat in intensive care units (ICUs). The aim of this study was to describe an XDRAB outbreak which was cross-transmitted in the ICU and respiratory intensive care unit (RICU) in a tertiary care hospital from January-March 2013.

Methods: Patient and environmental surveillances were performed. Isolates were tested for antimicrobial susceptibility. Genotypes were analyzed by multilocus sequence typing (MLST). A series of enhanced strategies were implemented to control the outbreak.

Results: A total of 11 patients were infected by XDRAB strains during this outbreak. Three patients in the ICU were found positive for XDRAB at the onset of the outbreak. Thereafter, infections were detected in 6 patients in the RICU, followed by reappearance of this strain in the ICU in 2 patients. All A baumannii strains isolated from patients and the environment were extensively drug resistant. MLST revealed them as ST368. After 3 rounds of environmental screening and cleaning, the laminar flow system connecting the ICU and RICU was found as the source of transmission. Successful control of this outbreak was achieved through multifaceted intervention measures.

Conclusions: This study suggested the importance of thorough surveillance and disinfection of the environment, including concealed devices, in preventing the transmission of an outbreak.