Infection prevention is a critical aspect of dental practice and the cleaning of surfaces between patients has a key role in infection control. Alcohol based surface disinfectants possess some of the widest disinfectant kill ranges available. They are rapidly bactericidal and are effective against TB, fungi and viruses. Recent evidence has demonstrated that Mikrozid alcohol based wipes effectively eliminate a range of microorganisms from surfaces, without any protein fixation.
When selecting a surface cleaner, consideration should be given to efficacy against a wide range of microorganisms, contact times, material compatibility and ease of use. Taking all of these factors into account will ensure the highest standards of best practice are met for both patient and staff safety.
HTM 01-05 6.61 recommends that: “The patient treatment area should be cleaned after every session using disposable cloths or clean microfibre materials – even if the area appears uncontaminated.”
Surfaces should be wiped down between patients with a high quality disinfectant. Besides the choice of disinfectant, the delivery format also needs to be considered. Heavy microbial contamination has been found on reusable cleaning cloths, so wiping hard surfaces with a reusable cleaning cloth can contaminate hands, equipment and other surfaces.
Wipes pre-saturated with the disinfectant of choice are usually the preferred format in a busy dental practice as they are convenient to use, disposable and require less storage space than sprays. Wipes also have the added advantage of containing the correct amount of disinfectant.
HTM 01-05 recommendations
- 6.46 All work surfaces where clinical care or decontamination is carried out should be impervious and easily cleanable.
- 6.54 The dental practice should have a local protocol clearly outlining surface and room cleaning schedules.
- 6.57 The use of disinfectant or detergent will reduce contamination on surfaces.
- 6.61 The patient treatment area should be cleaned after every session using disposable cloths or clean microfiber materials – even if the area appears uncontaminated.
Selecting a disinfectant wipe
An ideal disinfectant should have a high inactivating capacity for a wide range of viruses, including HIV and hepatitis, as well as being effective against bacteria, including tuberculosis. It should be safe to use and suitable for frequent application. There are two main types of disinfection available for wiping hard, non-porous surfaces: those that are alcohol based and those that are non-alcohol based. The non-alcohol ones are usually types of quaternary ammonium compounds known as ‘quats’.
Alcohol based disinfectants are rapidly bactericidal, they are also effective against TB, fungi and viruses. Alcohol based surface disinfectants possess some of the widest disinfectant kill ranges available. They are virucidal against ‘enveloped’ viruses, such as HIV and hepatitis B and against the ‘non-enveloped’ viruses, such as poliovirus rhinoviruses and hepatitis A. Alcohol-free formulations like quats are generally regarded as ineffective against TB bacteria and non-enveloped viruses such as polio.
In addition to microbial contamination, surfaces may also be contaminated with protein residues such as blood and pus. It has been suggested that alcohol may bind protein to stainless steel and the presence of protein may compromise the efficacy of alcohol based wipes. However, the most recent evidence to test the protein binding hypothesis, found that Mikrozid alcohol wipes when used with a double-wipe technique did not fix protein to stainless steel.
The study was performed in conditions to simulate those found in a dental practice. Alcohol wipes were tested on three different surfaces (including stainless steel) against the microorganisms commonly found in dental surgeries, in the presence of protein residues. To assess that a sufficient number of microorganisms could be killed, 1,000 cells of each microorganism was inoculated onto each surface. The final results, given no survivors were recovered, showed that a 1,000-fold microbial kill had been achieved.
To simulate the effect of potential protein fixation, a pure protein was used (albumin), with each surface containing three percent protein contamination.
The protein-contaminated surfaces were double-wiped with the alcohol based wipes. Each surface was left for one minute to allow the disinfectant to penetrate the microorganisms. The action of the alcohol based wipe was then measured.
The results of the study demonstrated that alcohol based wipes achieved a three-log reduction in the microbial challenge, in the presence of pure protein residue. No protein fixation was observed at any stage of the study. The study author concluded that “Mikrozid alcohol based wipes are effective in eliminating a range of different microorganisms from surfaces, in the presence of protein residue. Dental practices can therefore use alcohol based
wipes with confidence for hard surface cleaning when the most effective spectrum of disinfectant activity is required, including all hard surfaces contaminated with protein residues.”
Surface disinfection – a two-stage process
When cleaning surfaces, it is recommended that a double wipe procedure is used. The first wipe cleans the surface and physically removes contaminants including dust, soil, large numbers of microorganisms and the organic matter
that protects them. The second wipe disinfects the surface; reducing the number of micro-organisms to a safe (or relatively safe) level. The initial cleaning stage is essential to remove any visible soil (such as organic and inorganic material) from the surface, as it may compromise the disinfectant process. Organic matter such as serum, blood or pus can interfere with the antimicrobial activity of disinfectants, meaning that the disinfectant is less effective. Organic material can also protect microorganisms from attack by acting as a physical barrier.
Following the cleaning stage, the disinfectant phase eliminates many or all pathogenic microorganisms, except bacterial spores from the surface – depending on the type of disinfectant used.
Successful surface decontamination can only be achieved by closely following the manufacturer’s specifications for use. For example the following instructions refer to the correct use of Mikrozid wipes.
Gloves should always be worn before using a ready-to-use pre-soaked wipe. The wipe is removed from the container by tearing off at a downward angle. The surface should be wiped thoroughly, ensuring that the surface
is completely moistened. The surface should be allowed to dry, before a second wiping procedure is used to ensure that the surface is effectively decontaminated.
Each wipe should only be used once and on one surface. It may be necessary to use several wipes for large surface
areas. Wiping in figure of eight loops is recommended to ensure that the complete surface area is covered (see diagram above). Wipes and gloves should be correctly disposed of after use. A double-wiping procedure should always be adopted. The first rub of the surfaces with the wipe removes the protein, and the second rub with a wipe
brings the disinfectant into contact with any remaining microorganisms, allowing the disinfectant to penetrate through the microbial cell wall and in the case of an alcohol based wipe, to destroy the microbe by denaturing its cellular proteins.
References available on request.