Multiplex PCR for Identification of Salmonella enterica serovars Typhi and Paratyphi A by Selective Amplification of tyv, prt, viaB, fliC-d and fliC-a Genes

Salmonellosis is responsible for large number of infections in both human and animals. Salmonella enterica serovar Typhi is a causative agent of typhoid fever and Salmonella enterica serovar Paratyphi A is a causative agent of paratyphoid fever. Conventional methods of isolation of Salmonella strains take 4-6 days to complete and are therefore laborious and require substiantial manpower. Therefore development of a PCR assay that can target multiple genes for rapid detection of S. Typhi and S.Paratyphi A. Methods: Synthetic primers for O, H, and Vi antigen genes, tyv , prt , fliC-d, fliC-a, and viaB, were used for the rapid identification of S. Typhi and Paratyphi A with Multiplex PCR. Results: All the clinical isolates examined were accurately identified by this PCR technique, that differentiated S. Typhi and Paratyphi A, based on size and number of amplified fragments. S. enterica serovar Typhi, yielded four bands of tyv(tyvelose epimerase gene, 615bp),prt (paratose gene, 258bp),flic-d(phage-1 flagellin gene for d- antigen 750bp) and viaB ( vi antigen gene, 439bp); S.enterica serovar Paratyphi A yielded only two bands prt (paratose gene, 258bp) and flic-a (phage-1 flagellin gene for a- antigen 329bp). Conclusion: These data indicate that multiplex PCR is a potentially valuable tool for rapid diagnosis of Salmonella enterica serovar Typhi and Paratyphi A from clinical isolates