Transmission of Hypervirulent Acinetobacter baumannii Between General and Intensive Care Unit

Abstract

Background Acinetobacter baumannii is one of the most important microorganisms associated with hospital-acquired infections and nosocomial outbreaks.Aim We investigate a hypervirulent A. baumannii outbreak with aim to identify the transmission mediator.Methods We investigated an outbreak in respiratory intensive critical care unit (RICU) and respiratory medicine unit (RMU) based on whole genome sequencing (WGS) and epidemiology data. Virulence potential was performed in a mouse model.Results Eight and two CRAB isolates were isolated in RICU and RMU during August 2018. Four fatal cases were all involved in a transmission event. In vivo test confirmed the hypervirulence phenotype of the isolates. We inferred that the portable devices were probably the mediator of the transmission based on the transmission chain and epidemiology data. We isolated an hypervirulent CRAB from the screen of portable ventilator. Portable devices disinfection using vaporized hydrogen peroxide and avoiding the sharing of devices between general ward and ICU successfully blocked the further transmission.Conclusions An emerging hypervirulent A. baumannii with enhanced virulence has successfully colonized on the surface of mobile medical device. Sharing these mobile devices may lead to spread between the general ward and ICU. The new transmission chain construction tool is useful to the outbreak investigation.