Rapid detection of Salmonella in water samples by multiplex polymerase chain reaction

A rapid protocol for detecting Salmonella species in water samples using the polymerase chain reaction (PCR) technique is described in this paper. Salmonellae, the etiological agents for typhoid fever, salmonellosis, and gastrointestinal infections, require more than 30 hours to be detected in water samples using current standard protocols. In epidemic conditions, where detection time is crucial, the multiplex PCR protocol developed can give results within 5 hours of collection of water samples. This latter protocol uses a gradient temperature program that allows simultaneous amplification of five different loci in a single reaction. The target loci used were invA, phoE, spvA, spvB, and 16s rDNA gene. The selected primers in the reactions allow the detection of a broad range of pathogenic Salmonella, whereas 16s rRNA locus was included as a reaction control for raw water samples devoid of Salmonella. The protocol has been successfully tried on standard strains and on samples collected from river water.