Burkholderia pseudomallei-specific recombinant protein and its potential in the diagnosis of melioidosis

Melioidosis is an important public health problem in Southeast Asia and Nor thern Australia. This disease is caused by the gram-negative bacilli, Burkh olderia pseodomallei. Wide spectra of clinical manifestations are observed in melioidosis ranging from asymptomatic to septicemic infection. Although serodiagnostic methods of melioidosis have been improved significantly in r ecent years, a highly specific diagnostic test that can differentiate asymp tomatic seropositive individuals and melioidosis patients remains to be the subject of current investigations. In this study, a B. pseudomallei-specif ic gene, pBps-1, expressing a novel 18.7 kDa recombinant protein was select ed from genomic libraries of two a. pseudomallei virulent isolates by using pooled sera from septicemic melioidosis patients. Nucleotide sequence anal ysis demonstrated that this gene is unique and does not show substantial si milarity with any known genes in the Genbank database. The Bps-1 recombinan t protein was evaluated for its potential in serodiagnosis of melioidosis b y Western blot analysis. A high degree of specificity was demonstrated usin g sera from healthy individuals in the endemic (98.5%) and non-endemic area s (100%), with moderate sensitivity (69.7%) in melioidosis patients. The st udy demonstrated that this approach can be used to obtain highly specific r ecombinant antigens such as that described in the present report. A combina tion of such antigens should provide materials for successful serodiagnosis of melioidosis in the endemic areas.