Welcome to the new Outpatient Surgery website! Check out our login FAQs.
ABC's of Surface Disinfection
Your guide to cleaning and disinfection of environmental surfaces.
Robert Manasse
Publish Date: October 1, 2008   |  Tags:   Infection Prevention

Materials that will be used during surgery must be sterile and free of all living microorganisms, be they bacteria or viruses. The same does not hold true of surfaces, which are continually exposed to the environment, making it impossible for us to sterilize them. The most we can do with surfaces is to reduce the microbial burden to a level that will significantly reduce the chance that there will be an infection caused by microorganisms on hands or surfaces. This is where disinfectants enter the scene. Disinfectants come in various forms for various purposes. They also have varying abilities to decrease the number of viable organisms present. Here are some helpful tips and points to keep in mind as you consider the right tool for your surface disinfection needs.

1. Disinfectants won't be sufficiently effective if the surface is dirty. This is especially true with proteinaceous substances such as blood. Disinfectants have to get to the area that has to be treated and organic matter of all kinds will prevent their penetration to the surface you want to disinfect. Treating the area with a detergent will usually take care of the problem by breaking up the material covering the surface to be disinfected.

2. One product for all surfaces. Ideally, you'll select a single product to disinfect OR surfaces. Choosing the best product for your conditions will depend on the types of surgeries performed and the environment in which your OR is situated, as well as the product's effectiveness against organisms of concern, cost, ease of use, storage, impact on surfaces and potential irritation to users' skin, eyes and mucous membranes.

Detergent, Disinfectant or Sterilant?

Here's how to distinguish among detergents, disinfectants and sterilants as they apply to the OR and its personnel.

  • Detergents. Usually a component of soaps, they serve to remove organic matter such as blood and oils from surfaces.
  • Disinfectants. Used to reduce the number of viable microorganisms present on a surface, whether inanimate or on a body, such as hands or a surgical site.
  • Sterilants. Designed to kill microorganisms that are in liquids or on surfaces.

3. What do regulators say? Four regulatory bodies influence the disinfectant you choose:

  • The EPA regulates chemicals that are used on such surfaces as OR tables, Mayo stands and gurneys.
  • The FDA oversees the effectiveness and safety of high-level disinfectants, generally used on equipment that will contact the human body, such as glutaraldehyde (Cidex), hydrogen peroxide and peracetic acid.
  • OSHA requires that in order to decontaminate a surface, the disinfectant must be effective against HIV or hepatitis B virus.
  • Part of the Joint Commission's infection control standard (IC.02.01.01.1) is the requirement "to minimize, reduce or eliminate the risk of infection."

4. Low, intermediate or high? There are three levels of disinfectants as categorized by the EPA:

  • Low-level disinfectants kill some viruses and bacteria but are unable to get rid of M. tuberculosis. TB is not transmitted from surface to surface. But its importance in disinfectant categorization is that the bacterium has an outside layer composed of lipids that is hard to penetrate. If the disinfectant can get through this outer layer, it should be able to get through the outer wall of most microorganisms.
  • Intermediate-level disinfectants kill most viruses and bacteria, including M. tuberculosis.
  • High-level disinfectants are chemicals that sterilize equipment that comes in contact with mucous membranes, such as fiberoptic endoscopes. They don't necessarily kill bacterial spores. They're usually used to reprocess reusable medical devices that shouldn't be exposed to high heat. These disinfectants are the ones used to sterilize equipment.

5 Disinfectant Myths

Despite numerous reasons and supporting documentation about the importance of disinfectant use, some still argue against routinely disinfecting surfaces in a healthcare setting. I've listed their arguments as myths on the left and countered them with what science tells us on the right.

Myth

Reality

1. Their use doesn't decrease infection rates in the healthcare setting.

Many studies from high-quality laboratories have been published in peer-reviewed journals demonstrating the efficacy of disinfectant use. Countries with the lowest rate of disinfectant use have been shown to have the highest increase in MRSA infections.

2. Both patients and employees can become allergic to them.

Yes, there's the potential of irritation with some agents, such as glutaraldehyde, but consider the need to decrease the bacterial load on specific surfaces. Careful use of agents that can affect the upper respiratory tract, skin and mucous membranes is very important. Read the Material Safety Data Sheet (MSDS) before using any chemical agent.

3. These chemicals have negative ecological effects.

There should be a well-thought-out use of disinfectants and their disposal.

4. Organisms will become resistant.

The chemical composition of many disinfectants makes it highly unlikely that pathogens will develop resistance.

5. It increases the cost of health care.

The estimated added cost of one surgical site infection far exceeds the cost of disinfectants.

5. Beware bacteria that form spores. Bacterial spores are like seeds, which explains why some bacteria survive harsh environments. Most disinfectants don't affect bacteria. Among the disease-causing bacteria that form spores are Clostridium difficile (C. diff) and Clostridium tetani (tetanus). An instrument used on a patient with C. difficile or an area that had a patient with the organism can become contaminated with spores very quickly. Unless you use adequate disinfection procedures and products, other patients and personnel handling the patient or entering the area may become colonized. The "right" conditions can change colonization to infection very quickly.

6. The big three bacteria. A disinfectant that is EPA-approved for use in an outpatient surgical facility must be active against three bacteria:

  • Salmonella choleraesuis, a Gram-negative rod that is used to represent bacteria such as Escherichia coli.
  • Staphylococcus aureus, a Gram-positive coccus. S. aureus is the same bacterium as MRSA, the organism we're all worried about. A disinfectant active against S. aureus will be effective against MRSA, too.
  • Pseudomonas aeruginosa, another Gram-negative bacterium. It's the cause of many nosocomial or hospital-acquired infections.

7. Stronger the agent, the better it kills? Not true for many disinfectants. A 1:10 dilution of household bleach (prepared fresh daily) is very effective in killing HIV as well as C. difficile vegetative cells and spores. One would expect 100 percent to be the best concentration of alcohol to kill bacteria and viruses, but mixing alcohol into a water-based solution makes it easier for alcohol to penetrate and kill cells. Alcohol gels and foams used as hand disinfectants are usually about 65 percent to 70 percent alcohol. This concentration is most effective in denaturing protein, thereby killing the germs. Quaternary ammonium compounds are usually used at dilutions of about 1:1,000. These chemicals, as well as most others, should be left on the surface for at least 10 minutes in order to be most effective.

Disinfectants: One Size Does Not Fit All

Based on this table, you might think that chlorine in the form of diluted bleach would be the best chemical to use for all types of disinfection. But bleach is very corrosive on some materials, including many metals used in surgical instruments as well as on flexible fiberoptic endoscopes. It can destroy expensive equipment quickly and even instantaneously in some cases. It's also very harmful to skin, eyes and mucous membranes. That's why you can't use bleach for all disinfection. It's always important to consider the specific uses, contaminants and types of equipment that are being disinfected.

Remember, however, that any reusable instrument that comes in contact with normally sterile tissue, including the bloodstream, should always be reprocessed using an autoclave, ethylene oxide or dry heat when possible. The specific uses and properties of any disinfectant can be obtained from the product's manufacturer. Data should include length of exposure required.

Most Frequently Used Classes of Disinfectants

Activity vs.

Chlorine
0.01% to 5%

Iodine
0.5% to 5%

Chlorhexidine
0.05% to 0.5%

Alcohol
70%

Phenol
0.2% to 3%

Bacteria

Good

Good

Good

Good

Good

Bacterial spores

Good

Poor

Poor

Poor

Poor

Viruses

Good

Good

Poor

Fair

Poor

• Enveloped viruses[1]

Yes

Yes

Limited

Yes

Limited

• Non-enveloped viruses[2]

Yes

Limited

No

No

No

Fungi

Good

Fair

Fair/Good

Good

Fair

SOURCE: CDC Web site
1. Enveloped viruses are surrounded by a lipid membrane usually derived from the infected host cell. They include HIV, herpes simplex virus, hepatitis B and C viruses and influenza viruses.
2. Non-enveloped viruses include noroviruses (the Norwalk agent), poliovirus, Coxsackie viruses, hepatitis A virus and rhinoviruses.

DID YOU SEE THIS?