Evaluation of Nested PCR in Blood Urin and Stool in Detection of Typhoid Fever by Sequences in the VI Region of the Flagellin Gene

Abouelnour A, Zaki MES and Elkannishy SMH

Published on: 2019-12-30


Background: Typhoid fever remains a leading cause of morbidity, mortality and economic loss regardless of age or gender in developing countries. A sensitive and specific test is urgently needed for the accuracy of the diagnosis. The clinical pictures are commonly misleading with other ferial diseases and diagnosis depends mainly on the laboratory. By using molecular method especially nested PCR it provides the highest sensitivity and specificity.

Objectives: To evaluate the sensitivity and specificity nested polymerase chain reaction (PCR) specific for Salmonella enteric a serovar. Typhi was used for the detection of the pathogen in blood, urine, and stool samples.

Methods: This was a prospective study which involved from 81patients with clinical suspicion of typhoid fever. In addition to 20 patients with febrile condition of cause other than typhoid. For each patient blood culture and widal test was done as in the routine lab processes of febrile condition.

Result: Out of 81 suspected cases of typhoid fever, nested PCR was able to detect gene sequences specific for S. typhi in 76 cases in blood and 56 cases in urine specimens each and 39 cases in stool specimens However, S. typhi was isolated from only 32 cases in blood culture. None of the febrile controls tested positive in blood culture, or PCR.