The spectrum of activity of disinfectants

Effectiveness spectrum

The effectiveness spectrum of disinfectants indicates which pathogens the product can kill and how efficiently it does so. Medical preparations for disinfecting skin and hands, surfaces, or medical instruments use various active ingredients, such as aldehydes, alcohols, phenols, octenidine, chlorhexidine, or ethylene oxide. Not all of these active ingredients are equally effective against every type of pathogen - in some cases, they are even ineffective.

The following pathogens are intended to be rendered harmless by medical skin or surface disinfectants:

• Bacteria & mycobacteria (e.g., tuberculosis)
• Viruses (enveloped and non-enveloped viruses)
• Spores
• Fungi

The effectiveness spectrum shows what a disinfectant can do

The respective effectiveness spectrum of a disinfectant can be found on the label and in the product description.

Here is an overview of the terms for the individual modes of action that make up the effectiveness spectrum of disinfectants:

• Bactericidal: Bactericidal disinfectants reliably kill bacteria. To be considered bactericidal, a substance must eliminate at least 99 percent of all bacteria in the area of application within four hours. Most bactericidal medical disinfectants are already effective against bacteria after just a few seconds.
• Tuberculocidal: Tuberculosis pathogens are also bacteria - more precisely, mycobacteria. The mode of action “tuberculocidal” is listed primarily for historical reasons, as Robert Koch's research into tuberculosis was crucial in demonstrating the transmission of disease by living microorganisms. Bactericidal disinfectants are often also tuberculocidal - nevertheless, manufacturers point out that tuberculosis bacteria are expressly killed as well.
• Mycobactericidal: Another term used to emphasize effectiveness against mycobacteria such as the tubercle bacillus. Mycobacteria are particularly resistant to antibiotics and disinfectants. In areas with an increased risk of contamination by mycobacteria, mycobactericidal disinfectants should therefore be used.
• Virucidal: A virucidal disinfectant is used specifically against viruses, with a distinction made between virucidal, limited virucidal, and limited virucidal PLUS. Virucidal means that all viruses - enveloped and non-enveloped viruses - are killed. A limited virucidal product eliminates all enveloped viruses, such as HIV, HBV, or HCV. If the disinfectant is limited virucidal PLUS, the non-enveloped adenoviruses, noroviruses, and rotaviruses are also inactivated in addition to enveloped viruses.
• Fungicidal: A fungicidal active ingredient kills fungi such as harmful molds. However, most fungicidal disinfectants must also be sporicidal in order to kill the spores through which fungi reproduce.
• Sporicidal: All spores of fungi and spore-forming bacteria (for example, Clostridium difficile) are reliably inactivated.
• Yeasticidal: Specific effectiveness against yeasts such as Candida albicans, glabrata, or krusei is described as yeasticidal activity.

Influence of contact time on the effectiveness spectrum

Depending on the product and manufacturer, ready-to-use disinfectant solutions contain different concentrations of the active ingredients. This results in different contact times until the various pathogens are killed.

For example, Bode's Sterillium® Gel pure disinfectant gel is effective against bacteria, mycobacteria, fungi, and yeasts within 15 seconds - however, a fully virucidal effect is only achieved after 60 seconds. Therefore, always observe the manufacturer's instructions for each individual product.

As a general rule, the longer a disinfectant is allowed to act, the more effective it is. The prerequisite for this is complete wetting of all surfaces or areas of skin to be disinfected. It is important to ensure that the disinfectant reaches all recesses and uneven areas, for example by thoroughly massaging it into all skin folds when disinfecting the hands.