Environmental Asepsis

The process of cleaning and disinfecting healthcare facilities is of the utmost importance to help ensure patient safety and prevent the spread of healthcare-associated infections.

Many pathogenic microorganisms can survive for extended periods of time from – days to weeks to months in the clinical environment. Both patients and practitioners can be infected through contact with contaminated environmental surfaces.9

Disinfection is the destruction of pathogenic and other species of microorganisms by physical or chemical means. Disinfection is less lethal than sterilization, because it can destroy the majority of recognized pathogenic microorganisms, but not all microbial forms (e.g., bacterial spores). Disinfection does not ensure the degree of safety associated with sterilization processes.

The disinfection process involves one or two steps or activities – For two steps, cleaning is performed first, followed by the application of an appropriate disinfectant. Its desirable to use a cleaner/disinfectant product that contains a detergent (surfactant) to first clean the surface plus chemical agents that are disinfectants and have broad and rapid antimicrobial activity. This saves having to take 2 separate products with you (i.e., a cleaner and a separate disinfectant). In recent years, spray type surface disinfectants have been supplemented by the use of disinfectant-containing wipes. These disinfectant wipes may be easier to transport than liquid disinfectants and disposable paper towels. A one-step process can be performed if the surface is not soiled or only lightly soiled – provided the product being used is both a cleaner and a disinfectant.

There are three basic types or levels of disinfectants used in dentistry:10

  1. High-level disinfection disinfection process that inactivates vegetative bacteria, mycobacteria, fungi, and viruses, but not necessarily high numbers of bacterial spores. FDA further defines a high-level disinfectant as a liquid sterilant used for a shorter contact time.
  2. Intermediate-level disinfectant Liquid chemical germicide registered with the US Environmental Protection Agency (EPA) as a hospital disinfectant with a label claim of being tuberculocidal (TB kill time will be noted on the label). Such agents destroy vegetative bacteria and the majority of fungi and viruses and inactivates Mycobacterium bovis, but are not necessarily capable of killing bacterial spores. Intermediate-level disinfectants are used on noncritical surfaces with visible blood.
  3. Low-level disinfectant Liquid chemical germicide registered with EPA as a hospital disinfectant. The US Occupational Safety and Health Administration (OSHA) requires low-level hospital disinfectants have a label claim for potency against HIV and HBV if used for disinfecting clinical contact surfaces. These can be used on noncritical surfaces only in the absence of visible blood.

The choice of specific cleaning and disinfecting agents is guided by product label claims and instructions and government regulations. Realistic use of liquid chemical germicides depends on consideration of multiple factors, including the degree of microbial killing required; the nature and composition of the surface, item, or device to be treated; and the cost, safety and ease of use of the available agents. In the case of intermediate- and low-level disinfectants used for clinical contact surfaces, choosing to use only an intermediate-level disinfectant addresses infection control requirements whether or not visible blood is present. In contrast, if a low-level disinfectant is used when no visible blood is present this means that the mission must also carry and stock an intermediate-level disinfectant for the situation where the surface has visible blood on it. To reduce product requirements, using only an intermediate-level disinfectant makes sense.

In some cases, protective covers, such as plastic, sheets, tubes or bags can be used as a barrier between surfaces and patient body fluids instead of having to perform cleaning and disinfection after treating each patient.. A combination of disinfection and protective covers can be effective and involves professional judgment. If covers are used, they must be removed, discarded and replaced between each patient. If they were damaged during use or removal, the underlying surface must be cleaned and disinfected before placing fresh barrier and treating the next patient.