Evaluation of three oligonucleotide primer sets in PCR for the identification of Burkholderia cepacia and their differentiation from Burkholderia gladioli.

AIMS To evaluate three oligonucleotide primer pairs--two specific for 16S and 23S rRNA sequences of Burkholderia cepacia, and the third specific for internal transcribed spacer region of 16S-23S sequences of B gladioli--for the identification and differentiation of reference and clinical strains of these and other species. METHODS The three primers sets were applied in polymerase chain reaction (PCR) to a collection of 177 clinical isolates submitted for identification from diagnostic laboratories as presumed B cepacia. RESULTS At an annealing temperature of 63 degrees C, all eight B cepacia and four B gladioli reference strains reacted with their specific primers. B vandii was the only other species that was positive with both B cepacia primers but five Burkholderia or Ralstonia species reacted with one of these primers. Seventy eight isolates were typical of B cepacia in biochemical tests and 75 of these reacted with specific primers; three, however, were positive with the B gladioli primers. Fifteen asaccharolytic isolates were confirmed as B cepacia by PCR but other non-fermenting Gram negative species were negative with each of the primers. CONCLUSIONS PCR using 16S rRNA sequences is recommended for identification of B cepacia that give atypical results in biochemical tests.