SPD/CSSD Hygiene Monitoring Systems: Protein & ATP Tests.

ATP testing was born to serve a specific purpose in the food industry market: to
monitor microbiological possible contaminations after washing/disinfection of
the surfaces and machines. After this, and as consequence of healthcare
acquired infections outbreaks a few decades ago, hospitals started to perceive
that they need to incorporate a similar control inside the SPD/CSSD. Since there
was no better technology or testing method available rather than ATP at that
time, both hospital’s urge and manufacturer’s smartness, led the market to
incorporate this testing method inside hospitals.
However ATP systems does not seem to be the best choice for this specific
purpose. And below a list of reasons why:

• The main objective of a washing/cleaning process in hospitals is to eliminate
blood and tissue remainings, thus guaranteeing that subsequent disinfection
and sterilization processes will be successful. Nowadays, the main challenge that
washer and detergent manufacturers face, is the complete removal of proteins
from reprocessed instruments. Thus, if we are talking about a test for cleaning
effectiveness, protein should be the chosen one, because, in biological samples,
there is nothing more adherent than proteins. In this sense, blood and tissue
residues consist of different cell types and free proteins. The most diffcult to
remove are the proteins that coagulate and adhere to the instruments, making
the washing process very di_cult to accomplish successfully. So, why bothering
to measure ATP levels if instruments will subsequently be exposed to a sterilization process to remove any living cell remaining? This points out ATP detection is mainly recommended for disinfection control in places like the food industry.

• ATP does not represent a contamination itself, so microbial or organic
contamination will always be an indirect measure (when measured by ATP). On
the other hand, protein residues do represent a direct measure of
organic/microbial contamination. Not only this, but more importantly, proteins
are the most di_cult to remove residues during a cleaning process. For this
reason, if we are talking about cleaning effectiveness, protein testing is
undoubtedly the best marker.

• ATP is a very easy to hydrolyse molecule, so it does not represent a challenge
to the washing procedure. In this sense, hospital washing/cleaning parameters
do guarantee that any ATP molecule will be destroyed during the process
(temperature, detergents or disinfectants, etc). Not only this, but if there is any
chance that ATP molecules remain after the washing cycle, free ATP will
inevitably hydrolyse within a few minutes. Consequently, it is very unlikely that an
ATP test will give a significant result after a hospital washing cycle.

• It has been proved that some ATP tests fail to lyse some bacterial cells, thus the
release of ATP for later detection may be compromised. (if we consider ATP as a
microbial testing). Again, for instruments that will undergo a sterilization process
after cleaning/disinfection, it would not be the best recommendation to test for
bacterial contamination.

• It has also been shown that some detergents and disinfectants used in
hospitals interfere with the bioluminescence reaction.

• ATP is not present in viruses and, more importantly nowadays, in Prions, protein
infectious agents composed entirely of a protein material that causes transmissible spongiform encephalopathies, such as variant Creutzfeldt-Jakob disease. Remarkably, proteins are one of the main components of viruses, while
prions actually are infectious proteins themselves.
The relevance of this issue is such that institutions such as the UK Department of
Health have set limits on micrograms (_g) of protein to consider an instrument
as “clean” in The Health Technical Memorandum 01-01 (HTM 01-01). Therefore it
is not enough with the simple detection of proteins, but also its quantification by
electronic systems of high sensitivity and temporary analysis of the evaluated
samples is important.

Chemdye® PRO1 MICRO represents an easy option to monitor the cleaning of
reusable medical devices in the context of medical, dental practices and industry
from the detection and quantification of surface proteins, allergens and reducing
agents. The system consists of a swab of special characteristics and two reactive
solutions contained in the same device. PRO1 MICRO offers a quantitative
colorimetric result that can be measured with high sensitivity using any of the
Bionova® Auto-readers: IC10/20FR, IC10/20FRLCD and MiniPro.

For the detection of microorganisms by means of ATP; the available system is
Chemdye® ATP-S1. This product is similar to PRO1 MICRO in its structure; but the
biochemical reactions are completely di_erent. In fact this one is based on an
enzymatic reaction. ATP, the energy source of microorganisms, triggers a light
reaction that can be measured in a Luminometer. It is worth to note that this
system does not recognize proteins of any nature.

In conclusion, proteins do fulfil all the requirements to be the marker molecule
for cleaning effectiveness monitoring. In fact, today our Chemdye® PRO1 MICRO
system has become the most reliable cleaning monitoring system in the market.
Additionally now with Chemdye® ATP-S1 the users can also access to highly
sensitive ATP detection system to fulfill their entire requirements related to
microbial contamination assessment.

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