Rapid and sensitive method for detection of Salmonella strains using a combination of polymerase chain reaction and reverse dot-blot hybridization.

We have developed a reverse dot-blot hybridization assay for detection of Salmonella using Salmonella-specific oligonucleotide probes designed from the base sequence of the 16S rRNA gene (rDNA). The target fragment of 16S rDNA was amplified, and labelled with biotin by the polymerase chain reaction. The amplified fragment was hybridized with the membrane-immobilized probe and the hybridization was detected by chemiluminescence. Amplified fragments from 24 different serovars of Salmonella hybridized with the probes, whereas those of species of Enterobacteriaceae, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus failed to hybridize. By this assay, it was possible to detect in the order of 10(4) bacteria in fish meat homogenate in 10 h.