Enriched PCR for Detection of Salmonella spp. in Mice

A pair of oligonucleotide primer was synthesized according to the invA gene nucleotide sequence within Salmonella specices. A new method of PCR was successfully developed by enrichment broth cultivation for the detection of Salmonella in laboratory animals.The DNA was extracted from 7 strains of Salmonella and 3 strains of non salmonella bacteria(by a rapid boiled lysate technique). All Salmonella yielded 284 bp specific band, while no specific product yielded in non salmonella bacteria. As few as 50 CFU of salmonella in pure culture could be detected by PCR. Three sample processing methods for mice feces, including low and high speed centrifugation, binding to glass powder, and selective enrichment cultivation, were used for the extraction of DNA template, and the corresponding sensitivities of the methods were 2×10 4,5×10 3,10 CFU, respectively. One hundred and five laboratory animals were detected for the salmonella by enriched PCR procedure and conventional culture technique. The results suggested that the enriched cultivation PCR have advangtages in rapid detection of Salmonella in a large number of laboratory animals