Development of nested PCR based on the ViaB sequence to detect Salmonella typhi

This is the authors' abstract. We don't add key points for this paper.

For a rapid diagnosis of typhoid fever, we developed a nested PCR based on the nucleotide sequence encoding the Vi antigen. All Salmonella typhi strains along with a Salmonella paratyphi C strain were PCR positive. This assay was able to detect S. typhi at the single-cell level. Typhoid fever is still one of the most important infectious diseases worldwide. The conventional culture method for de-tecting Salmonella typhi in clinical samples takes 2 to 5 days and sometimes takes more than 1 week with blood samples. Many successful approaches for rapidly detecting S. typhi have been reported (for example, detection of typhoid antibody or antigen and by DNA probe assay), but these methods are limited by poor sensitivity. Recently, a nested PCR based on the H1-d flagellin gene was reported to detect S. typhi in blood samples (2). It demonstrated that a nested PCR assay is sen-sitive enough to detect S. typhi directly from blood specimens. However, this assay is not applicable to the clinical specimens