Control of Environmental MDR Acinetobacter baumanii with Hydrogen Peroxide with Ag+ Vapor Disinfection

Background: Rapports of critically injured soldiers returning home with MDR A. baumanii complex (MDR-ABC) infections are well described (Scott, Clin Infect Dis, 2007). Environmental sources probably play a role for further transmission in hospitals. In 2008-9, three patients with MDR-ABC infections where admitted to our posttraumatic neurorehabilitation unit. All patients were isolated in single rooms with bathroom. Daily cleaning and disinfection was performed with chlorine. At discharge the three rooms where decontaminated using hydrogen peroxide with Ag+ vapor. Nosocomial transmission with this strain was not seen in our hospital, but in two other Danish hospitals.

Objective: To investigate the effect of hydrogen peroxide with Ag+ vapor, Sterinis® (Gloster Sante, Europe) on MDR-ABC) for decontamination of the patient environment.

Methods: Pre-disinfection environmental sampling, to investigate contamination with MDR-ABC after routine disinfection cleaning.
Intervention, post discharge room decontamination with hydrogen peroxide vapor with Ag+ .
Post-disinfection environmental sampling, to investigate the efficiency of the intervention.
Uniform environmental sampling based on a checklist was performed with dip slides in the patient’s room and bathroom. A gentamicin disc was placed on the dip slides to assist isolation of MDR-ABC.
After patient discharge the environment was decontaminated, using the hydrogen peroxide with Ag+  vapor for 3 cycles.
Post-disinfection sampling was performed as above.

Results: Despite daily cleaning with chlorine, 32 of 78 pre-disinfection environmental sampling from the three rooms were positive with MDR-ABC. These included: hand-hygiene facilities, faucet, soap and alcohol dispensers, glove boxes, bed, shower heads and bathing stretchers. Before using hydrogen peroxide with Ag+ vapor the rooms were stripped of all disposables. Four of 55 post-disinfection samples were positive. These samples came from a faucet, showerheads and bathing stretcher in two of the bathrooms. 

Conclusions: Environmental decontamination with hydrogen peroxide vapor was effective.  However, in areas such as the showerhead and other bathing equipment, where hydrogen peroxide vapor interfaces with water, disinfection is challenged. This problem has been solved by thermal disinfection of these units.