Pharmaceutical manufacturers around the world have recognized the economic benefits of implementing adenosine triphosphate
(ATP) bioluminescence for the rapid microbial screening of a wide range of raw materials, work in-process, and finished goods.
One way to achieve this is with the Celsis Rapid Detection System, which more than 450 industrial facilities on six continents
have implemented.
The Celsis ATP bioluminescence technology detects the presence of microbial contamination within 24–48 hours rather than the
3–5 days required by traditional methods. This translates to quantifiable financial benefits in a few principle areas of manufacturing
operations. For example, by reducing quarantined inventory and manufacturing cycle times, manufacturers also reduce their
safety stock and working capital requirements. This leads to better utilization and return on invested working capital. In
addition, by using rapid screening, contamination is identified faster, corrective action is more timely and effective, and
losses associated with contamination are minimized.
Although ATP bioluminescence is a very sensitive technique that is widely accepted and broadly used, it does have its limitations
for certain product applications. Definitive detection is based on having a sufficient quantity of microbial ATP present that
can generate a light signal that is distinguishable from product background. If the product itself has a high background based
on ATP from non-microbial sources, or the product is contaminated with an adaptive, slow-growing organism, then definitive
detection becomes more difficult.
Companies have overcome these two technical issues by moving to the Celsis "AKuScreen"which utilizes a two-step, two-enzyme
system that further decreases time to result. The AKuScreen technology is based on the amplification of microbial ATP and
is not constrained by the finite amount of ATP available in a standard bioluminescence assay. Amplification of microbial ATP
is accomplished by exploiting microbial adenylate kinase (AK) that is also present in all living organisms. It is possible
to use AK to generate almost unlimited amounts of its product because this is an enzyme, rather than a metabolite. The reaction
catalysed by AK is:
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This amplification allows for greater differentiation and a more sensitive measure of microbial contamination. Therefore,
companies can more effectively screen products with elevated background of nonmicrobial ATP and products contaminated with
adaptive, slow growing organisms. Also, the time to result is reduced to 18–24 hours compared to 24–48 hours with standard
ATP bioluminescence and 3–5 days with traditional methods.
How it works
Applying Celsis technology, the adenylate kinase (AK) enzyme in a bacterium can be made to produce within one minute approximately
40 times its current volume of ATP. If the reaction is allowed to continue for 25 minutes, the amount of ATP can be 1000 times
greater than what the organism contained originally. The end result is a much higher signal (positive result) when compared
to standard bioluminescence.
Another benefit of the core technology is the high signal-to-noise (S/N) ratio. This ratio is an indicator of a test kit's
ability to distinguish between a contaminated sample and regular background generated from a product sample. AKuScreen exhibits
a significantly higher S/N ratio than the standard ATP bioluminescence assay. As the AK assay continuously generates ATP,
sample background noise is proportionately smaller as compared to traditional ATP bioluminescence. Additionally, because of
this strong signal, the assay read time can be further reduced, minimizing the impact of background noise generated from non-microbial
ATP in the sample. This increases the sensitivity of the assay and removes any uncertainty of the end result.
A number of companies have derived value from deploying the rapid AK method of microbial detection.
