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Microbial identification through DNA amplification 
A novel technique based on polymerase chain reaction (PCR) amplification of DNA sequences may provide the food industry with a rapid and inexpensive method of identifying microorganisms. Automated ribotyping has been applied very successfully at CCFRA for characterising microorganisms below species level, and is increasingly used for identification as the associated database is improved.To complement this technology, the possibility of developing an identification system based on the capture of PCR-amplified DNA sequences onto DNA microarrays was investigated. A microarray is a solid surface such as a microscope slide, onto which the amplified DNA (or any other macromolecule of interest) is bonded. These microarrays can then be used to probe an unknown organism of interest to see which of the DNA sequences on the array are also present in the organism. Microarray probes were designed for selected groups of bacteria, based on regions of the 16S ribosomal RNA. A successful PCR protocol was developed and validated for Enterobacteriaceae, Pseudomonas, Bacillus and Clostridium species. Although observed hybridization did not always match that predicted by computer analysis of sequences, the research supported the belief that PCR/hybridization protocols will become a preferred technique for microbial identification. Contact: Chris Baylis |