Comparison of clean surfaces contamination by bioluminescence technology and microbiological technic

Objective

Compounding process is validated with microbiological control of surfaces with a delay of 2 to 5 days required. Rapid microbiological detection technics based on detection of microbiological growth are marketed alternate sterility methods. The aim is to compare bioluminescence technology with standard microbiological technic to the Laminar Air Flow Hood surfaces control. There are 2 parameters: detection limit and rates of positivity.

Method

Serial 10-fold dilutions were realized for each microorganism (Candida albicans, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella sp). We inoculated 10 to 1000 CFU on sterile inox surfaces previously cleaned with detergent-disinfectant (d-D), or not.

Results

Detection limit is different depending on microorganism for each method, but limit detection is always 10 times less for microbiological technology. Positivity rates of microbiological technic are higher than bioluminescence technology (67% vs 10% for surfaces not cleaned with d-D). ATP-bioluminescence detects small quantity of ATP after d-D cleaning, whereas microbiology does not detect any viable microorganism. These results should be interpreted cautiously, because bioluminescence detects ATP, while viable microorganisms are searched.

Discussion – conclusion

Bioluminescence and microbiological positivity rates can only be compared for important inocula (10⁵ CFU). Microbiology technic detection limit is higher than bioluminescence detection limit. This bioluminescence technology is not suitable for Laminar Air Flow Hood surfaces controls, because it cannot detect small quantity of viable microorganisms.otechnie.