Widal antibody titre test versus blood culture; which is a better diagnostic for typhoid fever?   

*1Popoola, O. D., 1Thomas, B. T., 2Folorunso, J. B., 1Balogun-Abiola, H. T., 1Adekola, H. A., 1Okulaja, Q. O., and 1Coker, M. O.

1Department of Microbiology, Olabisi Onabanjo University, Ago Iwoye, Ogun State, Nigeria

2Department of Medical Laboratory, Directorate of Health Services, Olabisi Onabanjo University, Ago Iwoye, Ogun State, Nigeria

*Correspondence to: [email protected]; [email protected]; +234-8075773022

ORCID: //orcid.org/0000-0001-6816-5627

 

Abstract:

Background: The importance of accurate diagnosis of infectious diseases is central and crucial to the effectiveness of treatment and prevention of the associated long-term complications of such infections. The objective of this study was therefore to determine the accuracy of the Widal antibody titre test in the diagnosis of typhoid fever relative to the gold standard blood culture technique.

Methodology: A total of 40 students attending the Olabisi Onabanjo University Health Services, Ago-Iwoye, Ogun State, Nigeria on account of suspected typhoid fever by positive Widal test (≥ 1/80) and not on antibiotic therapy, were recruited for the study. Stool and blood samples were collected from each participant and analysed at the medical laboratory of the health center using conventional culture techniques and confirmation of isolates by simplex and multiplex polymerase chain reaction (PCR) amplification assays of hilA (Salmonella enterica), ipaH (Shigella spp), rfc (Shigella flexneri) and wbgZ (Shigella sonnei) genes. Antibiotic susceptibility testing (AST) of isolated bacteria to 10 panel of antibiotics was done using the Kirby Bauer disk diffusion test and interpreted according to the Clinical and Laboratory Standards Institute (CSLI) guideline.

Results: Of the 40 patients with suspected typhoid fever by the Widal test, 9 yielded Salmonella enterica giving a 22.5% isolation rate, with Salmonella enterica serovar Typhi (Salmonella Typhi) confirmed as sole bacterium from blood cultures in 5 (12.5%) patients and co-infection of Salmonella and Shigella from stool samples in 4 (10.0%) patients. A total of 52 enteric bacteria isolates were recovered from blood and stool samples of the 40 patients made of Salmonella enterica 9 (17.3%), Shigella spp 20 (38.5%), S. flexneri 9 (17.3%) and S. sonnei 14 (26.9%). All the enteric isolates were multi-drug resistant (MDR), with resistance rates to the antibiotic panel ranging from 33.3%-100%, and all the isolates were resistant to ceftriaxone and pefloxacin. Salmonella isolates were also 100% resistant to nitrofurantoin, ofloxacin and ciprofloxacin; S. flexneri were 100% resistant to nitrofurantoin, amoxicillin, cotrimoxazole, ofloxacin and ciprofloxacin; and S. sonnei were 100% resistant to nitrofurantoin and cotrimoxazole.

Conclusion: These results showed that only 12.5% of typhoid fever diagnosis by Widal test had Salmonella Typhi isolated from their blood cultures while Salmonella enterica and Shigella spp were isolated from stool samples of other cases. There is need to adopt culture techniques for laboratory diagnosis of febrile illnesses in order to improve treatment regimen. The fact that AST can also be performed with culture technique could further guide antibiotic prescription and reduce the risk of emergence of resistant bacteria.

Keywords: Blood culture, Typhoid fever, Widal test, Salmonella enterica, Shigella spp.

Received Jun 6, 2022; Revised Jul 7, 2022; Accepted Jul 8, 2022

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Widal antibody titre test versus blood culture; which is a better diagnostic for typhoid fever?