Enhanced serodiagnosis of melioidosis by indirect ELISA using the chimeric protein rGroEL-FLAG300 as an antigen

Background The accurate and rapid diagnosis of melioidosis is challenging. Several serological approaches have been developed using recombinant antigens to improve the diagnostic indices of serological tests for melioidosis. Methods Fusion proteins from Burkholderia pseudomallei (rGroEL-FLAG300) were evaluated as a potential target antigen for melioidosis antibodies. A total of 220 serum samples from 38 culture proven melioidosis patients (gold standard), 126 healthy individuals from endemic (n = 37) and non-endemic (n = 89) Thai provinces and 56 patients with other proven bacterial infections as negative controls were tested using indirect enzyme-linked immunosorbent assays (ELISA). Results Using an optical density (OD) cut-off of 0.299148, our assay had 94.74% sensitivity (95% confidence interval (CI) = 82.3–99.4%), 95.05% specificity (95% CI = 90.8–97.7%), and 95% accuracy, which was better than in our previous work (90.48% sensitivity, 87.14% specificity, and 87.63% accuracy). Conclusion Our results suggest that the application of chimeric antigens in ELISA could improve the serological diagnosis of melioidosis and should be reconfirmed with greater patient numbers.