Combination of ATP-bioluminescence and PNA probes allows rapid total counts and identification of specific microorganisms in mixed populations.

We have combined ATP-dependent bioluminescence with a novel chemiluminescent in situ hybridization (CISH) method using peroxidase-labeled peptide nucleic acid (PNA) probes targeting species-specific rRNA sequences to provide total counts and subsequent identification of specific microorganisms. Both methods are applied to the same membrane filter following a short incubation time and both methods provide results in the form of spots of light that are captured by the MicroStar detection system. Each spot of light represents individual micro-colonies detected by either ATP bioluminescence or PNA CISH. This new concept is particularly intended for in process and quality control of non-sterile products to rapidly provide total counts as well as presence/absence of specific indicators and/or pathogens in non-sterile, filterable samples.