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Four Common Questions About Surface Disinfection
The keys to booting bacteria, viruses and other microorganisms, from the groundup.
Nathan Hall
Publish Date: November 17, 2007   |  Tags:   Infection Prevention

With all the publicity surrounding the MRSA superbug, we thought now would be an interesting time to discuss how well you disinfect the surfaces in your facility. There are a lot of disagreements and misunderstandings about which agents to use and what surfaces you can use soap and water for instead of disinfectants. We talked to several experts to get their takes.

1 What's the best disinfectant for your needs?
When it comes to picking the best disinfectant, you need to get something that is registered with the EPA and compliant with your state's regulations, says Jack Wagner, president of Micro-Scientific Industries in Rolling Meadows, Ill. "There is no room for people to make a judgment," he says. "If you're in a healthcare facility and you're not using an EPA-approved agent, you will be fined. It's like driving without a license, you just can't do it."

But it's also important to be sure that the agent you're getting is specifically tested and approved for the microorganisms you're trying to control. "Some people take a cavalier attitude here and use the same disinfectants for everything," he says.

To make sure you're getting the right disinfectant for your needs, Mr. Wagner suggests looking for:

  • Approval. The agent should be EPA-approved as a cleaner as well as a disinfectant.
  • Marker viruses. These are the viruses the disinfectant has proven effective against, so it should be able to destroy the cells of viruses that are at least that strong. In healthcare facilities, it should be able to kill tuberculosis, staphylococcus, pseudomonas, salmonella, hepatitis B and C viruses, HIV and poliovirus.
  • Timeliness. The disinfectant's label should list how long it takes to effectively disinfect the surface against all organisms. Some products have multiple times on the labels, so consider the longest "kill time" the required contact time.
  • Compatibility with the surfaces. Be sure the agent is approved for hard surfaces, including plastics and stainless steel, and won't leave potentially harmful residuals or otherwise damage the surface it disinfects.

Is Your Office Equipment a Contaminant?

Do you realize that keyboards can be reservoirs for pathogens? At the 15th annual scientific meeting of the Society for Healthcare Epidemiology of America in 2005, researchers from the Northwestern Memorial Hospital in Chicago presented a study that showed VRE and MRSA could survive for 24 hours on the raw keys or keyboard covers. What's more, the covers didn't do anything to prevent the transmission of these bacteria.

The investigators determined that washing your hands before typing can reduce the number of these diseases each touch spreads, but there's no harm in disinfecting your keyboard. William Rutala, PhD, MPH, professor of the department of infectious diseases at the University of North Carolina at Chapel Hill and his colleagues did an experiment to see how well common disinfectants treated the pathogens on a keyboard and whether the keyboards would be damaged after 300 wipes. They found that quaternary ammonium compounds, 70% isopropyl alcohol, phenolic and chlorine (80ppm) were all very effective in removing or inactivating MRSA and PSAE without wiping away any of the key's letters or making them any less functional. They recommended that keyboards should be disinfected each day for about five seconds as well as whenever they are visibly soiled.

Dr. Rutala also says that computer keyboards that are used in patient care areas should be disinfected daily and when visibly soiled. In an effort to prevent contamination of computers, healthcare personnel shouldn't touch computer keyboards with contaminated hands. If a keyboard cover is used, he suggests that it should be disinfected using these same recommendations.

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But if you're dealing with more resistant culprits, such as if you know you have Clostridium difficile, Bob Manasse, PhD, an infection control consultant with Western Maryland Health System in Cumberland, Md., recommends using more powerful solutions like diluted bleach with chlorine. "The spores that these organisms form are quite resistant to the majority of agents," he says.

Some infection control specialists have found success when including bleach in their techniques to control an outbreak. A specifically formulated 10 percent bleach and water solution was the only thing that helped when C. diff struck the Maine Medical Center in Portland, says Gwen Rogers, RN, MS, CIC, manager of the hospital's department of epidemiology. "We're one of the facilities that was invaded by the strain from Canada that is stronger than it used to be, so we had to be very aggressive," she says. "We sent some cleaning products to an English company in collaboration with our antibiotic stewardship program and found that any of the pre-made products, even those with bleach, seemed to cause the spores to intensify due to the stabilizing ingredients."

The overall research behind bleach has been favorable. The CDC recommends using a diluted hypochlorite such as an EPA-registered bleach agent or diluted household bleach on its Web page titled "Clostridium Difficile Information for Healthcare Providers." A study presented at the Infectious Diseases Society of America found that using bleach in a universal cleaning protocol reduced the rates of C. diff infections by two-thirds at a New Orleans hospital, even though it had no apparent effect on MRSA and VRE infection rates.

But Mr. Wagner says bleach will not be effective for C. diff outbreaks due to the microorganism's hard shell and tendency to be surrounded by biological material that can neutralize its effectiveness. He says bleach can also damage the surfaces of medical equipment.

2 Are you taking enough time?
"The length of time it takes to do the disinfection is our biggest concern," says Ms. Rogers. "Most disinfectants take a minimum of 10 minutes to do their job, and when time is money, like it is in a doctor's office or a surgery department, that 10 minutes seems like a long time."

But this is nothing you can shave a few minutes from, says Jeanette Harris, MS, an infection control professional at Multicare Health Systems in Tacoma, Wash. "There's all kinds of studies that have been done that show you have to be sure of the timing," she says. "Whenever we clean something, it needs to have a wet time that varies depending on the solution used so we can be sure it's effective."

To keep turnover time to a minimum without compromising patient safety, Ms. Rogers says her staff prioritizes by starting with the surfaces that need the most time. "Do the most critical things first, then move on to other things that will take up that time," she says. "If you need to wash a bed or a stretcher or exam table, do that before you do the floor."

3 Do you disinfect your floors?
So while you may be using powerful disinfectants to take care of anything that could come into contact with the patient, will a detergent be sufficient to take care of the surfaces that do not come into contact with patients? There are a couple of different views on this subject.

Surfaces for disinfection purposes fall into one of three categories, according to a 2004 presentation from William Rutala, PhD, MPH, professor of the department of infectious diseases at the University of North Carolina at Chapel Hill, titled "Disinfection and Sterilization: Issues and Controversies" (available at http://disinfectionandsterilization.org):

  • critical surfaces, such as surgical instruments and implants, which need full sterilization;
  • semi-critical surfaces, such as endoscopes and anesthesia equipment, that will come into contact with mucous membranes or sites without intact skin and need high-level disinfection; and
  • non-critical surfaces, which include medical equipment that makes contact with the patient, such as BP cuffs, and housekeeping surfaces, such as bedside tables.

Obviously the critical and semi-critical surfaces need to be thoroughly treated, but what about the non-critical surfaces that play a more theoretical role in disease transmission?

"We always use disinfectants for everything including the floors," says Ms. Harris.

"I don't think floors need to be disinfected, because if something hits the floor, then it's dirty and it needs to be cleaned or thrown out," says Ms. Rogers. "But other items that come into contact with the patient should be disinfected, because every patient deserves a clean environment."

"If you spot-clean to disinfect any spilled blood or bodily fluids, then it's OK to use soap and water when cleaning the floors," says Mr. Wagner. "But anything above waist-level requires high-level disinfection."

According to Dr. Rutala, the medical equipment in this category should be disinfected for at least one minute with an EPA-registered agent. As for the floors and walls, soap and water is fine unless the floors are visibly soiled (If the staff isn't sure if a spot is blood or dirt, it's best to treat it as blood) or if you suspect multi-drug resistant organisms are present.

4 How do you find the source of an outbreak?
Even if you follow all the guidelines to the letter and spare no expense at reducing the risk, an infection rate of zero is still impossible. But when this rate increases sharply because of an outbreak of a particular infection, Dr. Manasse says it's time to do some detective work. "One tries to work back to what is called the ????-??index' case, which is the first patient that can be linked to having the infection or at least colonized by the causative organism," he says.

The first step to spotting infections is to keep track of all your patients' infection rates and the symptoms they show, says Ms. Harris. "If you only have one patient with an infection, it's hard to track it to the source," she says. "So we constantly look for patterns to see if we can find a patient here and another one there with this condition."

When you have a few cases of similar infections, Ms. Rogers says you should try to find out if there are any common elements between the patients and the infections they received. "You have to look at the time, their location, the products used, and the person, and if the infections are spread out try to see a link between them," she says. "For example, infections could be linked because the patient had a caregiver in common."

Every facility should have a plan in place to investigate outbreaks, says Ms. Rogers, even though many times the source simply isn't found. "You don't find out where the infection came from, but you implement a lot of things at once to stop the outbreak and suddenly it stops," she says. "Often, it comes down to a breakdown somewhere in the process, where someone isn't doing something they should, so when you start investigating and implementing new measures, the staffers get back in line."

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