With an outbreak of the extensively drug-resistant pathogen Acinetobacter baumannii (XDR-Ab), patient screening and daily chlorhexidine baths were part of a comprehensive outbreak control strategy, a new study suggested.

XDR-Ab transmission within hospitals has been documented via direct and indirect patient contact, inadequate sterilization of medical devices, contamination of rooms, and colonized health care workers, said Dr. Yves Longtin, chair of the infection prevention and control unit at Jewish General Hospital in Montreal. Dr. Longtin and his coauthors described the epidemiology and control of an XDR-Ab outbreak that involved multiple units of a large Canadian hospital in a recent article published in the Journal of Hospital Infection.

The outbreak was the result of a single clonal strain of XDR-Ab that colonized or infected 29 patients, 5 of whom died of XDR-Ab bacteremia. Transmission occurred primarily on two wards, either directly between patients or indirectly through staff, shared equipment, or the environment, investigators found. There is currently no consensus on optimal screening procedures, nor on the best combination of interventions to prevent transmission among patients, Dr. Longtin and his colleagues said.

The outbreak described in the study ended following the application of intensive screening, environmental disinfection, source control, reinforcement of routine hygiene, and isolation procedures including cohorting and unit closure. Intensive screening – screening of rectum, groin, throat, urine (in catheterized patients), wounds, and other catheter sites – revealed that 57% of infected patients were rectal carriers of the bacterium. Thus, a single rectal screening, considered standard for detection of carbapenem-resistant Enterobacteriaceae, would not have been sufficient to detect all infected patients.

Colonized patients received daily chlorhexidine baths, a strategy that is a useful tool in the control of other antibiotic-resistant nosocomial pathogens, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, but is not mentioned in the recent acinetobacter-specific guidelines or reviews, Dr. Longtin and coauthors said. They hypothesized that the prompt resolution of the outbreak may have been due in part to the use of the chlorhexidine baths.

Read the full study in the Journal of Hospital Infection ( doi: 10.1016/j.jhin.2015.12.013 ).

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