Production and evaluation of recombinant Burkholderia pseudomallei GroEL and OmpA proteins for serodiagnosis of melioidosis.

Melioidosis is a bacterial infectious disease caused by Burkholderia pseudomallei (B. pseudomallei). The variable clinical manifestations of this disease make its diagnosis difficult. The gold standard strategy for diagnosis is bacterial culture and identification, which is time-consuming and often too late for early medical intervention. Therefore, a rapid and accurate diagnosis of melioidosis is needed for effective treatment. This study aimed to produce and evaluate two purified B. pseudomallei recombinant proteins (rGroEL and rOmpA) as potential antigens for melioidosis diagnosis by ELISA. A total of 218 serum samples from Thailand was analysed. The study includes melioidosis patients' serum samples confirmed by bacterial culture (n=38); sera from patients with various bacterial infections but negative for B. pseudomallei (disease control, n=55); and sera from healthy individuals from non-endemic (n=77) and endemic (n=48) regions. The rGroEL ELISA achieved a good sensitivity of 92%, which was higher than that of rOmpA ELISA (76%). The specificities of rGroEL and rOmpA ELISAs were 88% and 90%, respectively. Both antigens demonstrated good diagnostic accuracy, at 89% (rGroEL) and 88% (rOmpA). There was less reactivity of sera from healthy individuals with rGroEL than rOmpA antigens. These data highlight the usefulness of rGroEL purified protein as a potential antigen for the serodiagnosis of melioidosis by ELISA and may be useful in the development of additional methods, such as dot blot ELISA or immunochromatographic tests (ICT), for a rapid, simple, cost-effective and efficient diagnosis for use in poorly resourced regions where melioidosis is endemic.