Although discharge cleaning in the hospital reduces contamination with multidrug-resistant Acinetobacter baumannii, it is not sufficient to remove the threat of transmission, a single-center study showed.

At discharge prior to room-cleaning, 46.9 percent of rooms used by patients who were infected or colonized by the pathogen were contaminated, and 15.3 percent of sites within the room tested positive, according to Anthony Harris, MD, MPH, of the University of Maryland School of Medicine in Baltimore, and colleagues.

After environmental services had completed post-discharge cleaning, 25 percent of the rooms and 5.5 percent of sites were still contaminated with the bacteria, the researchers reported in the December issue of the American Journal of Infection Control.

"Persistent room contamination serves as a potential reservoir for transmission and colonization of future room occupants," noted the authors, who called for further research on more effective cleaning methods.

"Novel methods, such as hydrogen peroxide vapor and ultraviolet light, have been shown to be significantly more effective," they wrote. "However, turnaround time may limit regular use and hinder implementation in hospitals."

Harris and colleagues conducted their study using rooms in the medical, surgical, and cardiac surgery intensive care units at the University of Maryland Medical Center. All 32 rooms included in the study had been occupied by a patient known to be infected or colonized by multidrug-resistant A. baumannii (susceptible to two or fewer classes of antibiotics).

Environmental samples were taken when a patient was ready for discharge and then again after cleaning had been completed by environmental services. The samples were collected from up to 10 sites within each room, including the sink drain and the edge of the basin, bed rail buttons, bedside table handle, vital sign monitor buttons, call button/remote, supply cart drawer handles, interior and exterior door handles, infusion pump buttons, ventilator machine buttons, and an area of the floor on either side of the bed.

The cleaning protocol involved disinfecting surfaces from high to low. Staff removed curtains, infusion pumps, and respiratory equipment, and wipes soaked in hospital-grade disinfectant were used to clean all surfaces. The floors were mopped with the same solution.

The researchers collected 487 cultures from 32 rooms from March 2009 to April 2011.

Before cleaning, contamination with the bacteria was most often seen on the floor, supply cart, bed rails, and ventilator.

After cleaning, which was associated with significant reductions in the percentage of rooms and sites that were contaminated (P≤0.01 for both), the most common areas of persistent contamination were the floor, bedside table, call button, door handles, and supply cart.

The researchers acknowledged that their study was limited by the lack of observation of the cleaning methods used. Thus, they said, it is possible that contamination rates after cleaning could be reduced through education and feedback to environmental services.

In addition, the study did not include molecular typing to match patient and environmental samples of the bacteria.

As reported by MedPage Today.