Assessment of blood culture and tube agglutination serology test for the diagnosis of typhoid fever amongst malaria-negative patients: a one-year hospital-based study

Salmonella serotypes, including Salmonella Typhi, S. Paratyphi A, S. Paratyphi B, and S. Paratyphi C, are responsible for the systemic, protracted febrile sickness known as typhoid fever. Various antibody-based tests are being used for diagnosing typhoid fever. This study was carried out to assess the performance of the widal test and blood culture for the diagnosis of typhoid fever among malaria-negative patients in a tertiary care hospital in east Delhi, India. The study was conducted from July 2021 to June 2022 in the Department of Microbiology of a tertiary care hospital in Delhi. Patients, including the adult and pediatric population, were evaluated for typhoid fever and participated in an observational, prospective study on febrile patients that was malaria-negative. Venous blood samples were obtained under strict aseptic conditions and further processed for widal serology and blood culture tests for typhoid fever. In our study, the prevalence of blood culture-positive Salmonella species was 0.3% (30/10,000 = 0.3%) Among antimicrobial susceptibility patterns, S. Typhi revealed the highest resistance rates for Ciprofloxacin (43.33%), Azithromycin (36.66%), and third-generation cephalosporins. Out of 30 blood culture-positive Salmonella Typhi of typhoid fever patients, 5 (17%) samples were negative for the Widal test. Among 30 samples, all were blood culture positive, but only 25 samples show Widal titer above the baseline i.e. >1:64. Although blood culture is the gold standard for the diagnosis of typhoid fever, the Widal test does play a role in the diagnosis and management of typhoid fever, especially in suspected cases when blood culture is negative, especially in government tertiary care hospitals.