Allelotyping PCR for Detection and Screening of Salmonella enterica Serovar Enteritidis and Typhimurium

Classical Salmonella sero-typing is an expensive and time consuming process that requires implementing a battery of O and H antisera to detect 2541 different Salmonella enterica serovars. During this study a rapid multiplex Polymerase Chain Reaction (PCR) scheme was developed to screen for the prevalent Salmonella enterica serovar Enteritidis and Typhimurium. By analyzing the nucleotide sequences of the genes for O-antigen biosynthesis including wba operon and the central variable regions of the H1 and H2 flagellin genes in Salmonella, designated PCR primers for two multiplex PCR reactions were used to detect and differentiate Salmonella serogroups A/D1, B, C1, C2, or E1; H1 antigen types i, g, m, r or z10 and H2 antigen complexes, I: 1,2; 1,5; 1,6; 1,7 or II: e, n, x; e,n,z15. Through the detection of these antigen gene allele combinations, the study was able to distinguish among Salmonella enterica serovars Enteritidis and Typhimurium. The assays were useful in identifying Salmonella with O and H antigen gene alleles representing ten distinct serovars. While the H2 multiplex could discriminate between unrelated H2 antigens, the PCR could not discern differences within the antigen complexes, 1,2; 1,5; 1,6; 1,7 or e, n, x; e,n,z15, requiring a final confirmatory PCR test in the final serovar reporting of Salmonella enterica.