yphoid fever is becoming an ever increasing threat in the developing countries.
Cultivation of bacteria and serology (especially Widal test) give unacceptable levels of
false-negative and false-positive results, respectively.
The aims of present work is development of a PCR assay that can target specific multiple
genes for rapid detection of Salmonella enterica serovar Typhi (S. typhi) .(which has 100%
specificity for Salmonella typhi) was compared with Widal test and Salmonella typhi
IgGIgM rapid test as well as Salmonella typhi IgG and IgM ELISA test during the first week
of illness of 50 suspected cases of typhoid.
PCR primers for invasion, O, H and Vi antigen genes, invA, prt, and viaB were designed and
used for the rapid detection of S. typhi by multiplex PCR.
The respective figures of positivity for PCR, Blood culture, Widal test and S. typhi IgGIgM
rapid test and Salmonella typhi IgG /IgM ELISA were 66%, 52%, 46%, 42% and 48%
respectively. A control group of 20 healthy persons gave figures of 0%, 0%, 40%, 0% and
0% respectively.
The present study conclude that this PCR-based technique is not only absolutely
specific, but also very sensitive and, therefore, much superior to Widal test, Blood culture S.
typhi IgGIgM rapid test and Salmonella typhi IgG/IgM ELISA tests for the early diagnosis
of typhoid. |