Comparative Study of Blood Culture and Widal Agglutination Test from the Patients Suspected of Enteric Fever

Aims: This study was performed to identify the enteric fever cases by both blood culture and Widal agglutination test and compare the results obtained from both methods.

Study Design: This research was carried out as hospital based descriptive cross-sectional study.

Methods: Blood samples collected aseptically from patients suspecting enteric fever were processed for identification of Salmonella species by blood culture and Widal agglutination test. The isolates were further subjected to antibiotic susceptibility testing according to CLSI guidelines. Total 1269 samples from the suspected patients were enrolled for this study and statistical analysis of the result was done by using 16.0 versions of SPSS.

Results: Among suspected patients studied, 70 (71%) and 29 (29%) cases were confirmed to be infected with S. typhi and S. paratyphi A respectively from blood culture. Out of total sera processed for Widal test, 263 samples gave agglutination with titre more than 1/80. The study showed sensitivity of 81.4% and specificity of 84.4%, positive predictive value of 31.5% and negative predictive value of 98.2% and the efficiency 84.4% of Widal test in compare to blood culture. S. typhi isolates sensitive to the classical first line drugs- amoxycillin, chloramphenicol and cotrimoxazole were 94.3%, 97.1% and 97.1% respectively while S. paratyphi A isolates sensitive were 68.9%, 96.5%, and 93.1% respectively. Fifty eight (82.9%) S. typhi isolates were nalidixic acid resistance while 25(86.2%) S. paratyphi A were nalidixic acid resistant. Also, 3(3.03%) multi-drug resistant isolates were confirmed to be nalidixic acid resistant.

Conclusion: The study showed blood culture remains the gold standard for enteric fever diagnosis. Widal test alone either positive or negative should not be considered confirmatory for enteric fever However cut-off titre can be taken in the diagnosis and Widal test can be helpful in making a presumptive diagnosis of typhoid fever if interpreted with care. Azithromycin and Ceftriaxone were the most effective drugs for enteric fever cases.