Study 2: Microbial Detection Optimization
Part 1: Six different fabric softeners were tested using standard and AKuScreen reagents. The fabric softeners were spiked
(<10 cells) with three yeast species and five Acetobacter species and enriched in SDB. The product-broth suspensions were
tested after 24, 48, 65 and 72 hours.
All three yeasts (Saccharomyces sp., Candida albicans, and C. guillermondii) were detected within 24 hours with both standard
and AKuScreen bioluminescence reagents. The following table is data for the five Acetobacter species. (See Table III)
Table III: Case Study 2, Study II, Methodology
Part 2: Five different naturally contaminated fabric softeners were tested using AKuScreen to determine the minimum incubation
time required to detect microbial contamination directly from naturally contaminated products. Each product was tested in
triplicate. The number of colony-forming-units (CFUs) per gram was determined at the same time the samples were set-up for
Celsis enrichment. The product-broth suspensions were tested after 24, 48, and 72 hours.(See Table IV)
Table IV: Case Study 2, Study II, Detection Using AkuScreen Assay
AKuScreen could detect Acetobacter species contamination within 48 hours. One of the replicates for the product with the lowest
bioburden was negative at 48 hours but could be detected at 72 hours.
Results: The data shows that product-adapted microorganisms can be detected faster using AKuScreen. Detection was optimized by using
a suitable enrichment broth. The detection system's ability to detect low numbers of product-adapted microorganisms is due
to the amplification of ATP using adenylate kinase technology in the AkuScreen reagents. The company was able to manufacture
and ship its fabric softener in a timely manner without having to worry about the downstream impact of a contamination event
identified after products had shipped.
Broad Application for Rapid Methods
The economic benefits of implementing rapid microbial detection methods are clearly recognized by pharmaceutical manufacturers
globally. The ability to release product faster is critical to effectively reducing manufacturing cycle times, reducing inventory
holding time, and thereby increasing available working capital.
On the technology side, ATP bioluminescence is broadly utilized and accepted for rapid screening on a wide range of materials
and finished goods. The use of AK can further shorten the detection cycle and improve key manufacturing metrics for many companies.
AK is especially important to consider in certain product applications where the use of standard bioluminescence has its limitations.
If a product has a high level of ATP from non-microbial sources, or if the product is contaminated with slow-growing organisms,
for example, definitive detection can be more difficult to achieve with standard ATP.
In these selected situations, as illustrated by the above case studies, Celsis AKuScreen offers definitive detection while,
at the same time, further decreasing time to result. Detection time decreases from 3-5 days with traditional detection methods
to 24-48 hours with standard ATP Bioluminescence to 18-24 hours with AkuScreen.
Lori Daane is vice-president of Scientific Affairs, Celsis, Inc., 600 West Chicago Avenue, Suite 625, Chicago, IL 60610-2422. tel. 312.476.1200,
fax 312.476.1201, firstname.lastname@example.org