Evaluation of fimC and bdha based duplex PCR for specific identification and differentiation of Burkholderia pseudomallei from near-neighbor Burkholderia species

Assays for the rapid detection and accurate differentiation of Burkholderia pseudomallei from near-neighbor species are urgently needed in melioidosis endemic regions due to the high associated mortality and biowarfare importance of the pathogen. PCR-based methods have revolutionized this field due to the accuracy, sensitivity, and specificity that are achievable in a rapid way. In this study, a compound molecular detection system, consisting of a duplex PCR assay, was developed for the specific identification of Burkholderia pseudomallei and differentiation from other Burkholderia species. For accurate identification of B. pseudomallei, we deciphered and adopted a novel gene termed putative fimbrial chaperone (fimC). D-beta hydroxybutyrate dehydrogenase (bdha), reported previously by our group for sequence-based differentiation of B. pseudomallei from other Burkholderia species, was employed as a genus-specific target. Enforcement of an internal amplification control in the PCR format ruled out possible false negative results in the assay. Thus, the developed PCR assay was highly specific (100%) in its detection features, and a clear detection sensitivity of 10 pg/mu l for purified gDNA and 3 x 10(3) CFU/ml for B. pseudomallei spiked urine was recorded. Successful identification of B. pseudomallei from an experimental mouse model at both the genus and species level revealed the accurate diagnostic efficiency of the duplex PCR method.