Development Of A Multiplex PCR Assay Targeting O-antigen Modification Genes For Molecular Serotyping Of Shigella Flexneri

ObjectiveTo explore a multiplex PCR assay to detect and identify 14 most common S.flexneriserotypes (1a, 1b, 1c, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, X, Xv, Y and F6) targeting the O-antigensynthesis gene wzx and the O-antigen modification genes gtrI, gtrIc, gtrII, oac, gtrIV, gtrV, andgtrX for molecular serotyping of S.flexneri.MethodsTo develop a multiplex PCR assay: Targeting the O-antigen synthesis gene wzx and theO-antigen modification genes gtrI, gtrIc, gtrII, oac, gtrIV, gtrV, and gtrX, we developed amultiplex PCR assay to detect and identify 14 most common S.flexneri serotypes (1a, 1b, 1c, 2a,2b, 3a, 3b, 4a, 4b, 5a, 5b, X, Xv, Y and F6) for molecular serotyping of S.flexneri.To validate availability: 358 S.flexneri strains of various serotypes were analyzed to validatethe method of availability.RusultsThe multiplex PCR assay contained eight sets of specific PCRs in a single tube and canidentify 14 of the 15 serotypes (the exception being serotype Xv) of S.flexneri recognized thusfar.A nearly perfect concordance (97.8%) between multiplex PCR assay and slide agglutinationwas observed when 358 S.flexneri strains of various serotypes were analyzed, except that 8strains were carrying additional cryptic and/or defective serotype-specific genes.The multiplex PCR assay contained eight sets of specific PCRs in a single tube and canidentify 8 genes every time, so provides a rapid and specific method for the serotypeidentification of S. flexneri.ConclusionThe multiplex PCR assay provides a rapid and specific method for the serotypeidentification of S. flexneri, which is identify 14 of the 15 serotypes (the exception beingserotype Xv) of S.flexneri recognized thus far. This method can be used in clinical analysis anddisease surveillance.