Development of a Slide Latex Agglutination Assay for Identification and Confirmation of Burkholderia pseudomallei from Cultures

Abstract

Culture and biochemical assay remain as “gold standard” for identification and confirmation of B. pseudomallei. However confirmation by API 20NE biochemical assay is time consuming as the identification can only be done 24 hours onwards up to a week. Consequently, treatment of the patients suspected for melioidosis can be delayed and increases mortality rate as death can occur within 24 hours onset of the disease. Therefore there is a need to develop an assay that can shorten the time for identification and confirmation of B. pseudomallei from cultures. In this study, a rapid slide agglutination assay was developed using a specific monoclonal antibody raised against culture filtrate antigen of B. pseudomallei in Balb-C mice. The purified monoclonal antibody was tagged onto 0.8 um latex particles by means of passive adsorption. Latex agglutination assay was performed on a total of 45 B. pseudomallei strains and additional of five other Burkholderia species on glass microscope slide. Cross reactivity studies were performed on control panel strains which consisted of various gram-negative and gram-positive organisms. The latex agglutination assay was able to identify correctly 44 of 45 B. pseudomallei strains with a remarkable sensitivity of 97.8% and specificity of 100%. No cross reaction was observed with the control panel strains. In addition, latex agglutination assay was also performed on various B. pseudomallei antigen and compared with the developed assay. It was found that the developed latex agglutination assay is useful in identification and confirmation of B. pseudomallei from cultures.