title: Development of a novel multiplex PCR for the detection and differentiation of Salmonella enterica serovars Typhi and Paratyphi A.
abstract: In this study, we developed a multiplex polymerase chain reaction (mPCR) assay for pan-Salmonella detection as well as for specific detection of serovars Typhi and Paratyphi A. The assay detects members of the Salmonella genus by amplifying the outer membrane protein C (ompC). The presence of either Salmonella serovar Typhi or Paratyphi A is indicated by amplification of the putative regulatory protein gene STY4220, which is common to both serovars. Further differentiation of the serovars was achieved by targeting the intergenic region (SSPAI) between SSPA1723a and SSPA1724 in serovar Paratyphi A, and stgA, a fimbrial subunit protein, in serovar Typhi. mPCR was evaluated using 124 clinical and reference Salmonella serovars. S. enterica serovars Typhi and Paratyphi A were detected at 100% specificity and sensitivity. Each PCR reaction detected approximately 1 pg of Salmonella genomic DNA. Sensitivity of the PCR when tested on 8-h-enriched spiked blood samples of serovars Typhi and Paratyphi A was estimated at 4.5 x 10(4)-5.5 x 10(4)CFU/ml, with similar detection levels observed for spiked fecal samples. This mPCR could prove to be a useful diagnostic tool for the detection and differentiation of serovars Typhi and Paratyphi A.
authors.affiliation: National University Hospital, Department of Laboratory Medicine, 5 Lower Kent Ridge Road, Main Building I, Singapore 119074, Singapore.
authors.forename: Grace Jie Yin
authors.initials: GJ
authors.lastname: Ngan
authors.forename: Li Mei
authors.initials: LM
authors.lastname: Ng
authors.forename: Raymond T P
authors.initials: RT
authors.lastname: Lin
authors.forename: Jeanette W P
authors.initials: JW
authors.lastname: Teo
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques / Q000379:methods*; D006801:Humans; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods*; D018272:Porins / Q000235:genetics; D012480:Salmonella Infections / Q000382:microbiology*; D012482:Salmonella paratyphi A / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012485:Salmonella typhi / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; C113724:OmpC protein; D018272:Porins