INFECTION PREVENTION & CONTROL
The advantages of enzymatic detergents
Contaminated flexible endoscopes are medical devices which may be associated with outbreaks of healthcare-associated infection.1
To minimise this
risk, effective cleaning and disinfection of flexible endoscopes must be undertaken. Dr Tim Sandle explains why, for this process to be effective, several steps need to be followed in a controlled manner.
Dr Tim Sandle
The first step, where a detergent is used at the pre-washer / disinfectant stage, is critical for the removal of soil and in preventing a biofilm community from developing.2 This step requires the use of a suitable detergent and following an agreed protocol.3 A detergent used for the cleaning of endoscopes should be of a medical device grade and carry a CE mark, be low-foaming (to help ensure the active chemicals remain in contact with the target surface), non-corrosive (and avoid discolouring the endoscope) and have proven cleanability. Detergents should always be used according to the manufacturer’s instructions, observing carefully the recommendations relating to detergent concentration, temperature and expiry date.
It is not sufficient to just soak the endoscope in a detergent solution; a degree of agitation is required, such as using a wipe applied to all external surfaces of the endoscope, together with uniform application of the detergent to ensure that all surfaces both internal and external, are treated. A key factor in determining how effective the cleaning process will be, relates to the type
of detergent selected and its formulation. There is an essential difference between enzymatic and non-enzymatic (‘neutral’) detergents. Generally, enzymatic detergents are considered to be more effective due to their ability to digest different types of soils and therefore facilitate the cleaning process. This article examines some of the differences between detergents used for the manual cleaning of flexible endoscopes, and considers some of the factors needed for the safe and effective application of detergents.
Effective detergents and endoscope cleaning
If an endoscope is not cleaned effectively it poses a risk to the patient in relation to the transmission of a microbial infection (infection from exogenous bacteria). This is likely to be caused by the presence of soil (such as blood or other bodily fluids) remaining on or inside the endoscope. Soil provides a growth source to enable bacteria to colonise parts of the device and form a biofilm, particularly within the inner channels of the endoscope.4
An additional concern is where the presence of soil acts
If an endoscope is not cleaned effectively it poses a risk to the patient in relation to the transmission of a microbial infection (infection from exogenous bacteria). This is likely to be caused by the presence of soil (such as blood or other bodily fluids) remaining on or inside the endoscope.
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as a barrier against the post-cleaning disinfection step applied.5
Due to their
complexity, flexible endoscopes are generally the most challenging to clean. During use the external surface and multiple internal channels of flexible endoscopes are exposed to bodily fluids and other potential contaminants, creating challenges for reprocessing. Flexible endoscopes are heat labile and therefore cannot be steam sterilised, so require chemical treatment for the second step.6 To achieve the appropriate level of cleaning, an effective detergent is required, followed by high-level disinfection, rinsing and effective drying. The detergent will be a chemical formulated to solubilise and remove both organic and non-organic soiling7 not damaging the endoscope itself.8
while The
detergent selected must also be compatible with the disinfectant (ideally the chosen disinfectant should be assessed against the ISO 15883 series of standards), otherwise any detergent residues may inactivate the active ingredient of the disinfectant. The removal of soil through the use of detergent cleaning is a key step, otherwise bacteria can be masked from the subsequent disinfection step, as most disinfectants have poor penetrative ability. Neutral anionic detergents rely solely on the activity of the surfactant and agitation to remove soil and to assist with the detachment of microorganisms from the endoscope surface; whereas enzymatic detergents contain one or more enzymes to facilitate the breakdown of soil. Making an informed choice between these two types of detergent should form part of a risk review of the endoscope reprocessing programme.
NOVEMBER 2019
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