Hospitals are also using fluorescent markers and other methods to test housekeepers' work. An old standby - bleach - is in a resurgence because it can kill C. difficile.
On the high end, several ultraviolet-light systems are competing with machines that fog a room with hydrogen peroxide. Johns Hopkins Hospital and Pennsylvania Hospital use the latter approach.
The fancy machines, which are used after normal disinfection, add time to what hospitals call "terminal cleaning," the work they do when a patient leaves a room. This puts them at odds with rising pressure to cut costs and maximize efficiency.
But hospitals are also under pressure to reduce infections acquired in house as well as readmissions. The goal is to turn over rooms as fast as possible without spreading disease.
Veronica Cessna, Doylestown's director of infection prevention, said the hospital saw the country's C. diff rate double between 2000 and 2009. Its own rate rose from 2.62 per 10,000 patient hours in 2009 to the current 5.7. "We wanted to get out in front of that," she said.
The 238-bed hospital started using a light-based system made by Xenex Healthcare Services of San Antonio in February. It is too early to tell whether the machine, which costs $125,000 for three years, is cutting infections.
The machine uses pulsing light to kill germs within 10 to 12 square feet. During Tuesday's demonstration, it had to be moved three times to cover an entire patient room and bathroom. (While the company's marketing materials call it a "robot," it can't move on its own.) That took about 15 minutes.
In this price range, cleaning is a catty business. Xenex representatives argue that their machine is better than competitors' because it uses more environmentally friendly xenon instead of mercury. They also say that the slight burnt-ozone smell after cleaning is less noticeable with their machine.
Bioquell, a Horsham company that makes the hydrogen peroxide system that Hopkins uses - it costs $40,000 - says its mist reaches nooks and crannies that light, which travels in a straight line, misses. It also says its mist is better than cheaper aerosolized peroxide systems. It takes about 90 minutes, though, which can really create traffic jams in a busy hospital.
Both approaches are dangerous to people, so the machine has to be left in an empty room. Ducts and door cracks must be sealed with hydrogen peroxide systems.
Figuring out what's best is frustrating. There's been no head-to-head scientific comparison of hydrogen peroxide and light, although there is evidence that both can reduce infections. Duke University and the University of North Carolina are partway through a 28-month study that will evaluate standard cleaning, bleach, and UV light.
Many hospitals are waiting it out for now. A recent survey by the Association for Professionals in Infection Control and Epidemiology found that only 9 percent of hospitals had used either UV light or hydrogen peroxide systems.
Many have switched to bleach for cleaning the rooms of C. difficile patients.
As to one of the more obvious questions - can I get a small version of one of these systems for my kitchen or bathroom? - the answer is no.
Contact Stacey Burling at 215-854-4944 or firstname.lastname@example.org.