Infection Control Today: inside central sterile

Keeping a Clean Slate
The Effort to Protect Instrumentation from Tough Infectious Agents Such as Biofilm and CJD Prions

By Kris Ellis

The constant battle to guard against the spread of infection and promote patient safety is waged on many fronts in each and every facility. As front-line participants, sterile processing department (SPD) personnel and infection control practitioners (ICPs) must focus their attention on variety of different elements, including surgical instruments and medical devices. Biofilm and Creutzfeldt-Jakob disease (CJD) are two very different threats that have the potential to cause problems for facilities if they take up residence on instruments and devices.

Biofilm can be generally defined as a group of microorganisms that form on a solid surface that comes in contact with water. As these organisms grow and multiply, they form a protective layer made up of polysaccharides. This layer can make any pathogenic organisms contained in the biofilm very difficult to eradicate. Biofilms have been implicated in several infections, such as bacterial endocarditis and Legionnaires disease, and can be extremely resistant to antibiotics.1

Biofilms are present literally in or on any device that sees water, says Martin Favero, PhD, director of scientific and clinical affairs at Advanced Sterilization Products. The reality is any kind of water will support these organisms to a certain extent. When organisms grow in a fluid, they tend to attach; they migrate to surfaces, they attach themselves to surfaces and then cover themselves with the socalled biofilm.

This phenomenon can become a serious concern from an infection control perspective. The importance is that, with some devices in some settings, especially those things that get disinfected, the organisms that are embedded in the biofilm, in spite of the fact they might be simple bacteria like pseudomonas, they take on the resistance that often approaches that of a bacterial spore because the germicide cannot penetrate the biofilm, Favero continues.

Theyre very tenacious and very difficult to get off of surgical instruments once they form, says Carla McDermott, RN, CNOR, education specialist, perioperative services, at Clearwater, Fla.-based Morton Plant Mease Hospitals. Its kind of like taking Scotch tape and winding it around and around itself it gets bigger and bigger the longer its left unmanaged.

McDermott explains that because biofilm is microscopic, it is sometimes difficult to communicate the importance of dealing with it and preventing it from forming. She points out that an aggressive approach with cleaning materials and tools is a necessity. You have to use a brush to clean this stuff, she continues. You have to use the proper mix of chemicals for disinfection and for the enzyme cleaners. It takes an enzyme cleaner to get through this stuff, but it takes physical friction as well its not something you can just soak and rinse off; that isnt going to help.

Stringent observance of proper cleaning procedures is the best defense against biofilm. Do not skip steps in the cleaning process, says Becki Jenkins, CST, RCST, CRCST, FEL, president and CEO of Sterilization by Design. Follow manufacturers recommendations for cleaning/decontamination of devices to include recommended solutions.

Jenkins explains that certain equipment can be more prone to biofilm formation. Instruments that are affected the most are lumens that are hard to reach or surfaces that are corrugated or textured and make effective cleaning difficult, she says. Insulated instruments present a concern when the insulation is not properly maintained and can thereby provide a safe haven for organisms between the insulation and the instrument. When in doubt, your instrument repair company can help you and you can send the instrument in question for testing.

Devices and instruments are not the only potential sources of biofilm. Washers and disinfectors can become colonized with biofilm, which can cause contamination on the instruments, says Stephen Kovach, BS, director of education at Healthmark Industries. Thats why as central service departments its important to use a descaler according to the instrument washer/disinfector manufacturers guidelines.

The use of a washer/decontaminator and/or ultrasonic washers, depending on the type of instrumentation being cleaned, can be effective in removing biofilm, says Rudolph Gonzales, RN, MSN, CNOR, CHL, CRCST, manager of the central sterile department at Medical Center of Louisiana in New Orleans. Gonzales also points out that inspection for visible bioburden is vital, as is the use of appropriate soaps and enzymatic cleaners, as well as thorough rinsing.

More complex instruments such as endoscopes may require different techniques. Ultrasonic cleaning using an enzymatic solution works well for us on lumened items and for fragile instrumentation, Gonzales continues. Cavitation that occurs in this procedure removes miniscule traces of tissue. Handwashing using enzymatic and instrument company-recommended detergents can also provide a reduction of biofilm when the other methods are not available. Visual inspection throughout the process will ensure that instruments are ready for sterilization.

Even when washers are in optimal condition, Jenkins points out that they alone are not enough. Please, please do not assume that a washer/decontamination unit, though very effective in removal of bioburden, will do all that needs to be done, she says. Never, NEVER skip steps in the cleaning and decontamination of instruments.

Kovach reiterates that it all starts with effective cleaning practices. The real part of helping to prevent biofilm is that youre cleaning and making sure youre getting it done as soon as possible and making sure whether youre doing it manually or its an automated process youre really monitoring it and making sure your equipment and your technique is good.

It all comes down to having properly trained and dedicated SP workers who pay attention to detail, Gonzales says in summary. All instruments that come to the SPD are infected with multiple sources for potential infection bacteria, viruses, protozoa, fungi, spores, antibiotic-resistant bacteria, etc., which require that all personnel use standard precautions every day for every instrument that is processed.


CJD, although extremely rare, remains a significant concern for infection control personnel due to the fact that no treatment currently exists for the disease, and the prions that cause it are unusually resistant to standard decontamination methods.2 This combination can be frightening, as evidenced by recent developments at Atlanta-based Emory University Hospital in which the facility notified 98 patients of possible CJD exposure.

Most infectious agents are living microorganisms, which can generally be killed by a biocidal substance of some sort. Prions, which are proteins, present a different type of challenge altogether.

When youre talking about a prion, youre talking about quite a different entity an infectious protein, says Peter Burke, PhD, senior vice president and chief technology officer at STERIS Corporation. We all have prions in our body that are normal, that cause us no harm;

something triggers a prion protein to become an infectious protein with abnormal structure, and that infectious prion has the ability to act like a chaperone protein that induces normal prion proteins to be become abnormal and infectious.

Burke notes that a prions basic chemical properties make it very difficult to eradicate. Let me give you a simple analogy, he says. When you cook something in a pan, during the cooking process you have lipids and proteins, and you have a variety of other types of matter. As you cook, you can fix that to the surface. Were all aware of how hard it is to get that off after cooking. In a hospital setting, when you let something dry, it has the ability to affix itself to a surface and it then has the tendency to be harder to remove.

Burke explains that prions that have affixed themselves onto instruments will develop a greater affinity to that surface if they are not loosened in some way early on. Coupled with that is the fact that when you now treat them with cleaning agents and processes, the theory that most scientists believe is the case for prions is that the surface prions (and other materials) will become inactivated or removed and the ones that are hidden below or remain on the surface afterward are still infectious and can transmit disease, he continues.

There are a number of guidelines and recommendations from various associations, such as the World Health Organization (WHO),3 regarding the disinfection of instruments that may house CJD prions. Oftentimes, the methods recommended are harsh and have the potential to damage fragile instrumentation. The specific procedures employed by different facilities may vary depending on their own unique circumstances, but basic precautions do exist that may be employed at any facility.

I think its very important that in most cases, hospitals will not know whether a person has one of these prion diseases, says Gerald McDonnell, BS, PhD, senior director of technical affairs at STERIS. CJD and other similar infections develop very slowly, and patients may not know they have been infected or carry the disease for a long time. This means that procedures could be performed and instruments used on a patient without knowing that the patient is infected. This is why universal precautions are recommended to avoid possible infection.

McDonnell describes these precautions as follows:

  1. Keep instruments moist
  2. Perform adequate cleaning to physically remove as much soil as possible
  3. Use cleaning chemicals that are effective at inactivating prions
  4. Use prolonged steam sterilization cycles

In the United States, I think people would tend to agree with Bill Rutala, says Favero. Basically what he recommends, and this will be reflected in the CDC guidelines on disinfection and sterilization once theyre published, the way they will read is unless you have three things going on, you really dont have to use a special protocol. The three things are, one: you have a patient who is either known or suspected to have prion disease. Secondly, the instruments in question are exposed to high-risk tissue such as brain tissue. Third, that the instrument be a critical instrument, which it would be automatically if it was a surgical instrument.

If those three conditions are present, deviation from normal sterilization protocol is recommended in favor of methods such as extended steam sterilization cycles and the use of sodium hydroxide. Favero adds that several recent publications have indicated that certain alkaline cleaners may also have potential in combating prions. I think this is good because I think the scientific community has finally combined prion sciences with disinfection and sterilization sciences, he says. Prior to this time, a lot of the prion scientists basically were not using the correct protocols for establishing whether or not a certain procedure could inactivate prions. I think weve turned a corner on that.

The harshness of the WHO-recommended treatment methods prompted STERIS to embark upon research in the area and eventually organize a study exploring methods of disinfecting prion-contaminated devices.4 There was a lack of qualified, complete studies on prion inactivation that were performed under laboratory control; STERIS undertook to conduct such a study, says Burke. The WHOrecommended treatments were used as positive controls, including sodium hydroxide, bleach and high-temperature treatment. In addition, new potential prion treatments were evaluated in comparison to the recommended WHO guideline treatments.

McDonnell notes that the purpose of the study was two-fold: to establish a methodology for testing prion inactivation, and to test existing and developing treatments using this methodology in a scientific, controlled manner.

Results of the study supported the efficacy of current WHO guidelines, but also noted potential drawbacks. The treatments recommended by the WHO did work to inactivate prions, although they were harsh for instrument surfaces and users, says McDonnell. However, autoclaving at 134 degrees Fahrenheit under recommended WHO conditions did not result in total inactivation.

The study also found that three milder methods of disinfection including a phenolic disinfectant, an alkaline cleaner, and the combination of an enzymatic cleaner and vaporized hydrogen peroxide (VHP) were also effective.5

Sorting through the wealth of information addressing disinfection and sterilization products and methods can become overwhelming, but Jenkins points out that adherence to established policies and procedures by well-trained personnel is the bottom line. The issue is in central sterile itself and whether or not there are certified or non-certified professionals, she says. In addition, it is critical that no step of the process be skipped, modified, shortened or otherwise manipulated to appease the push for faster turnover or a rush case in the operating room. The consequences could be costly and devastating to patients and their families. Stand up for the rights of patients first, surgeon preference second and convenience dead last, if at all.

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