August 3, 2009

New sanitizer reduces infections, cuts back on costly disposables

Johns Hopkins experts in applied physics, computer engineering, infectious diseases, emergency medicine, microbiology, pathology and surgery have unveiled a 7-foot-tall, $10,000 shower cubicle–shaped device that automatically sanitizes in 30 minutes all sorts of hard-to-clean equipment in a highly trafficked hospital Emergency Department. The novel device can sanitize and disinfect equipment of all shapes and sizes, from intravenous line poles and blood pressure cuffs, to pulse oximeter wires and electrocardiogram wires, to computer keyboards and cell phones.

The invention, dubbed SUDS for “self-cleaning unit for the decontamination of small instruments,” has been shown to initially disinfect noncritical equipment better than manual cleaning, the team reports in the Annals of Surgical Innovation and Research online July 27.

Surgeon Bolanle Asiyanbola, the study’s senior author, says that the four-year SUDS project was sparked by the rapid rise in use of expensive disposable items, a trend linked to efforts to prevent bacterial infections among patients in hospitals.

Drawing on her experience in the operating room, where many batches of surgical clamps, retractors and scalpels have been sterilized, decontaminated and safely reused for decades, Asiyanbola put together a team to end what she calls the “wasteful and unnecessary” practice of wiping down a lot of heavily used items with disinfectants and applying a lot of elbow grease. “If we can safely reuse equipment in the operating room, then we can do it elsewhere in the hospital for noncritical equipment,” she said.

In the study, the Johns Hopkins team showed that SUDS was able to disinfect some 90 pieces of used emergency-room equipment, placing as many as 15 items in the device and “fogging” the equipment with an aerosolized, commercially available disinfectant chemical, or biocide, called Sporicidin. None of the electronic circuitry appeared to be damaged by the decontamination process. Instruments tested were of the type that comes in direct contact with a patient’s skin, the body’s key barrier to infection.

Repeated swabbing and lab culture testing of each decontaminated instrument showed that all items remained free of so-called gram-positive bacteria for two full days after cleaning, even after the equipment was returned to the Emergency Department and reused. On the bacteria-free list were such potentially dangerous superbugs as methicillin-resistant Staphylococcus aureus, known as MRSA, and vancomycin-resistant Enterococcus, or VRE.

By contrast, testing of an equal number of similar items that were manually scrubbed down with a disinfectant solution called Airex showed that 25 percent of the devices had bacterial growth after two days, including growth of potentially dangerous gram-positive bacteria, such as MRSA and VRE, as well as gram-negative type bacteria, most notably Pseudomonas aeruginosa and Acinetobacter baumannii, plus some types of fungi.

“Our study results with the prototype offer strong evidence that more can be done to disinfect noncritical equipment through automated decontamination processes in heavily trafficked areas of the hospital,” said Asiyanbola, an assistant professor at the School of Medicine. “We believe this SUDS device has the potential to further protect our patients and staff from hospital infections and save health care dollars by making it possible to clean and reuse more kinds of hospital equipment.”

The Johns Hopkins inventors, who have patent applications pending, say that more studies must be done to determine if SUDS is effective for other hospital superbugs, notably Clostridium difficile.

Asiyanbola worked closely with Karen Carroll, director of Microbiology and a professor of pathology and medicine, and Allison Agwu, an assistant professor in Pediatric Infectious Diseases, to assemble the team to help test the prototype. Funding was provided by a grant from the Department of Surgery at The Johns Hopkins Hospital.

In addition to Asiyanbola, Carroll and Agwu, Johns Hopkins University researchers involved in this study were Chidi Obasi, Richard Rothman and Tracy Ross, all of the School of Medicine; Wale Akinpelu and Roger Hammons, of the Applied Physics Laboratory; Clyde Clarke and Ralph Etienne-Cummings, of the Whiting School of Engineering; and Peter Hill and Stella Babola, of the Bloomberg School of Public Health.

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