Abstract:
Diagnosis of typhoid fever is a major issue in Sudan due to the
lack of facilities in most microbiological laboratories. The
objective of this study was to investigate Salmonella typhi in
patients with typhoid fever phenotypically and serologically.
Blood and stool specimens were collected from patients
suspected to have typhoid fever. Serum was aseptically
separated after clot reaction by centrifugation at 3000 rpm for
5 minutes. The serum was used to perform Widal tube method
according to standard protocol. Two –fold serial dilutions of
serum were prepared in small test tubes with normal saline.
0.05 ml of O antigen was added to each test tube, the same
step was repeated for B-O antigen. The tubes were incubated
in a water bath at 37 °C overnight. Negative and positive
controls were included in each batch of the test. Stool
specimens were cultured firstly on Selenite F broth and
incubated at 37 °C overnight then sub- cultured on xylose
lysine deoxycolate agar plates. The plates were incubated at
37 °C overnight. Biochemical tests were adapted to identify
Salmonella typhi .
The results revealed that 14 out of 100 tested sera examined
were positive (Titre ≥1/160) for typhoid fever. The rest 86
serum specimens were negative (Titre ≤ 1/160). Cultivation of
100 stool specimens reveled that only 4 species of Salmonella
typhi and 1 species of Salmonella paratyphi B were identified.The study concluded that the Widal test remains one of easy
accessible, cheap and simple test but the culture is still remain
.the golden standard method to diagnosis of typhoid fever
