Differentiation between non-virulent and virulent Burkholderia pseudomallei with monoclonal antibodies to the Ara+ or Ara- biotypes.

Burkholderia pseudomallei is the causative agent of melioidosis, a fatal tropical infectious disease endemic in Southeast Asia. Environmental isolates of B. pseudomallei have two distinctive biotypes. Some soil isolates are arabinose-assimilators (Ara+ biotype) and are non-virulent in experimental animals. The others cannot assimilate arabinose (Ara- biotype) and are virulent in experimental animals. The Ara- biotype is found in almost all B. pseudomallei clinical isolates. In the present study, a panel of eight monoclonal antibodies that agglutinate the bacteria were produced and tested. The first group, Bps-D2, -D3, -D5, -L1, and -L2 agglutinated 100% of Ara+ clinical and soil isolates of B. pseudomallei. Another group Bps-A1, -A2, and -D1 agglutinated 92.9% and 90.9% of Ara- clinical and soil isolates, respectively. This panel of monoclonal antibodies may be useful for rapid differentiation between non-virulent Ara+ and virulent Ara- B. pseudomallei.

Rapid identification of Burkholderia pseudomallei in blood cultures by latex agglutination using lipopolysaccharide-specific monoclonal antibody.

Melioidosis, an infection caused by Burkholderia pseudomallei, is endemic in Southeast Asia. The septicemic form of melioidosis is the leading cause of death due to community-acquired bacteremia in the northeastern part of Thailand. The delay in isolation and identification of the causative organism is a major contributing factor to the high mortality. The present study describes the evaluation of a latex agglutination test for rapid identification of the bacteria directly from blood cultures. The Bps-L1 monoclonal antibody recognized the lipopolysaccharide antigen of 96.8% of B. pseudomallei clinical isolates and was highly specific for B. pseudomallei. The diagnostic value of the latex agglutination test based on Bps-L1 monoclonal antibody was prospectively evaluated in an area endemic for melioidosis. The agglutination test kit was evaluated in 88 blood cultures with gram-negative bacteria identified with Gram staining. The sensitivity and specificity of the test kit were both 100%. These results indicated that the detection of B. pseudomallei lipopolysaccharide by specific monoclonal antibody in a latex agglutination format is clinically useful for the rapid identification of the bacteria in blood cultures in areas endemic for melioidosis.