New Technique for Identification of Bacterial Spores Featured on Cover of Applied Spectroscopy


Research at the Pacific Northwest National Laboratory (PNNL) has led to a new technique for identifying strains of bacterial spores that requires a minimum of preparation of test samples and gives highly accurate results. An article on the project is featured on the cover of the August 2003 issue of the widely read journal Applied Spectroscopy. The technique is based on the combination of Fourier Transform Infrared (FTIR) spectroscopy and Photoacoustic spectroscopy (PAS). FTIR offers good differentia­tion among highly similar substances, while PAS enables the technique to be used on solid samples without the need for extensive pretreatment. The research group developed new algorithms for classification of samples based on the FTIR-PAS experimental results. With this spectroscopic/statistical approach it was proved possible to differentiate bacterial from non-bacterial materials, determine which bacterial samples corresponded to ones in the FTIR-PAS reference library in the laboratory, and to identify the exact strain of those bacterial spores. An accuracy of better than 90% was obtained at each stage. Further research is planned to expand the range of bacteria in the library, to determine the effect of varying growing conditions, and to test the applicability of the technique to mixtures of spores. The instrumentation has the potential to be made portable for testing of samples in the field. The project was carried out at the William R. Wiley Environmental Molecular Sciences Laboratory at PNNL and supported by Laboratory Directed Research and Development funds.