When University of Maryland (UMD) School of Medicine researchers sampled 10 surfaces in each of 50 rooms, multidrug-resistant Acinetobacter baumannii (MDR-AB) was found in 48 percent of rooms of patients colonized or infected with MDR-AB, and 85 percent of it matched the strain of the infected patients in those rooms, according to a study published in the November 2011 issue of the American Journal of Infection Control (AJIC).
Surfaces sampled included door knobs, bedrails, bedside tables, vital-sign-monitor touchpads, nurse call buttons, sinks, supply-cart drawer handles, infusion pumps, ventilator touchpads, and floors near beds. Most commonly contaminated were:
- Supply-cart drawer handles (20 percent)
- Floors (16 percent)
- Infusion pumps (14 percent)
- Ventilator touchpads (11.4 percent)
- Bedrails (10.2 percent)
Researchers noted that surfaces often touched by healthcare workers during routine patient care are commonly contaminated and may be a source of nosocomial transmission.
In independent research, two studies, each using five individual test surfaces, evaluated the disinfecting capability of a novel steam vapor disinfection system (TANCS, Advanced Vapor Technologies, Seattle) on surfaces colonized by Acinetobacter baumannii.
Very brief treatments of the surface produced substantial reductions in the pathogen load; more than 97.5 percent of bacteria were killed within the first 2 seconds of treatment, says Benjamin Tanner, PhD, chief researcher and principal of Antimicrobial Test Laboratories in Round Rock, Texas. Total disinfection of A. baumannii on surfaces occurred within 5 seconds in both trials.
For each experiment, greater than 10 million viable A. baumannii in a 5 percent artificial soil suspension were spread over porous clay surfaces resulting in at least 2 million viable A. baumannii cells present in the dried inoculum. Areas were then treated briefly with the saturated steam device, for periods of 0.5, 1, 2 and 5 seconds.
"Microbial reductions in typical use of the device may be even greater than in testing because test surfaces were highly porous and cooled immediately after treatment, Tanner adds. The trials suggest that the unit tested is a rapid, reliable and consistent non-chemical means to disinfect surfaces contaminated with A. baumannii.