Detection and speciation of bacteria through PCR using universal major cold-shock protein primer oligomers

The detection of bacteria using PCR is a well-established diagnostic technique. However, conventional PCR requires the use of DNA primer oligomers that are specific to the target organism and, as a consequence, a sample can only be tested for the presence of that specific target. A significant advantage would be to probe a sample for the presence of any bacteria, followed by identification. To achieve this it is necessary to identify a DNA sequence common to all bacteria. Here we demonstrate that such a sequence may be that encoding the major cold-shock proteins. Using two universal PCR primer oligomers from conserved regions of these gene homologues, we have amplified a 200 base-pair DNA sequence from more than 30 diverse Gram-positive and Gram-negative bacteria, including representatives from the genera Aeromonas, Bacillus, Citrobacter, Enterobacter, Enterococcus, Escherichia, Klebsiella, Lactobacillus, Lactococcus, Listeria, Pediococcus, Photobacterium, Proteus, Salmonella, Shigella, Staphylococcus, Streptococcus, and Yersinia. Sequence analysis of the amplified products confirmed a high level of DNA homology. Significantly, however, there are sufficient nucleotide variations to allow the unique allocation of each amplified sequence to its parental bacterium.