Chemiluminescent assay for detection of viable microorganisms.

The redox reaction between quinone and viable microorganisms produces active oxygen species. In this study, the production rates of active oxygen species were determined by a luminol chemiluminescent assay, and the luminescence intensity was found to be proportional to the viable cell number. The high sensitivity of the luminol chemiluminescent assay was achieved with Mo-ethylenediaminetetraacetate complex and menadione or coenzyme Q1. The detectable cell densities of bacteria and yeasts were found to be approximately several thousand colony-forming units (CFU/ml) when assays were performed with a 96-well microplate luminometer. The chemiluminescent assay requires 10 min for incubation of quinone and microorganisms and 2s for photon counting. Single Escherichia coli was detected after 4h of cultivation and centrifugation (5 min x 2). This simple chemiluminescent assay is expected to be useful for the rapid detection of viable bacteria and yeast.