Background: Typhoid fever continues to be a major health problem in many parts of the world, particularly the developing countries. The rate of typhoid fever is increasing in Egypt. Clinical diagnosis of enteric fever is difficult, as the symptoms associated with enteric fever overlap with those of other febrile illness. The objective of this study is to validate a PCR technique for the detection of typhoid infection. So, we can differentiate between the true and current infections by this organism from the falsely positive antibodies produced from previous or treated infections.
Methods: This study comprised 115 patients (88 males and 27 females) from different ages experienced the clinical symptoms of typhoid fever. This study was carried out at Mansoura University Hospitals. The blood samples collected were subjected to culture, Widal test and PCR targeting the hto gene of S. Typhi.
Results: PCR standardized for hisJ (hto) gene result in specific amplicon of 495-bp. In positive PCR cases of typhoid (total 15), a single band of 495bp corresponding to hisJ (hto) gene was obtained. The PCR assay was found to be highly specific and the true positive typhoid cases (n = 9) are positive of Widal test, blood culture and/or PCR. PCR was sensitive than blood culture for diagnosis of typhoid fever.
Conclusion: We recommend using PCR as an alternative to blood culture for diagnosis of typhoid fever. We also recommend performance of a large scale study to test this PCR technique for screening for tyhoid fever in Egypt.
Key words: Typhoid fever, widal test, blood culture, PCR.