Menadione-catalyzed luminol chemiluminescent assay for the viability of Escherichia coli ATCC 25922

Escherichia coli ATCC 25922 produced O-2(-) in the presence of menadione, a nd O-2(-)-dependent luminol chemiluminescence intensity was proportional to colony-forming unit (CFU) in the exponential phase. CFU was determined by using a 96-well plate at a range of 3 x 10(3) to 8 x 10(7) CFU /well (0.1 m l) after a 10-min incubation with menadione, followed by chemiluminescent a ssay for 5 s. After a 4-hr incubation of E. coli (10(5)CFU/0.1 ml) with men adione and an antimicrobial agent inhibiting the synthesis of peptidoglycan , protein, and DNA, the inhibitory concentration (IC) of the antimicrobial agent determined by menadione-catalyzed luminol chemiluminescent assay was in good agreement with minimal inhibitory concentration (MIC) of the NCCLS (National Committee for Clinical Laboratory Standard) method requiring 18 h r. Menadione-catalyzed luminol chemiluminescent assay is expected to be use ful for the rapid determination of cell viability under the conditions of v arious cell growths and stresses.