FIREFLY LUCIFERASE ASSAY OF ADENOSINE-TRIPHOSPHATE AS A TOOL OF QUANTITATION OF THE VIABILITY OF BCG VACCINES

The purpose of the present study was to compare conventional colony fo rming unit (CFU) enumeration with a bioluminescent measurement in orde r to quantitate living bacteria in BCG vaccine. Forty batches of BCG v accine quantitated with respect to weight (10 each of concentration 12 0 mg/vial, 30 mg/vial, 1.5 mg/vial and 0.75 mg/vial, respectively) wer e tested. Adenosine triphosphate (ATP) was extracted using the boiling Tris-EDTA extraction method preceded by treatment with the ATP-hydrol ysing enzyme apyrase, and the liberated ATP was assayed using a LKB 12 51 luminometer. The sensitivity of the assay was 10(-11) M ATP which c orresponded to 5 x 10(5) CFU/ml. A proportional relation between CFU a nd ATP content per vial was found up to 30 mg/vial, but for 120 mg/via l the CFU method seemed unreliable in contrast to the bioluminescence method. The measurements error for the logarithm (base 10) of ATP was 0.051 and this method was therefore more exact than the CFU method (0. 097). Because the bioluminescence method is sensitive, reliable, time- saving and less expensive it seems preferable to CFU enumeration in th e quality control of BCG vaccines.