Phosphorescence in Bacillus Spores

The rapid classification and identification of bacteria and bacterial spores by non-invasive means remains largely unsolved. U.V. fluorescence is becoming an accepted method for detecting the presence of biological aerosols. In other studies, auto fluorescence of bacteria has been shown to be useful in identifying bacteria in a medical application. Our present work attempts to build on this approach for environmental applications. We have measured a change in the fluorescence spectra of suspensions of Bacillus bacteria between the vegetative bacteria and their spores at room temperature. Furthermore, we have measured a significant change in the spore fluorescence as the spores are dried. Upon drying, increased light emission is measured at wavelengths longer than 400 nm. We identified this emission as phosphorescence. The phosphorescence spectra have the potential to be used to aid in bacterial spore detection and identification. INTRODUCTION Previous work by one of the present authors showed that the use of fluorescence technology can be adapted to a rapid noninvasive technique that successfully identifies the bacterial species commonly causing acute otitis media (middle ear infections) is present in an animal model. We will briefly review this application since it shows that autofluorescence of bacteria has broader potential than some have indicated.