ABSTRACT
An indirect immunofluorescent assay to detect antibodies against the lipopolysaccharide (LPS) of Burkholderia pseudomallei and taxonomically closely related species was developed with the Luminex system. LPSs of Pseudomonas aeruginosa, Burkholderia cepacia, Burkholderia thailandensis, Burkholderia vietnamiensis, B. pseudomallei, and Burkholderia mallei were successfully conjugated to Luminex microspheres. Antibodies measured against the LPS of B. pseudomallei-conjugated Luminex beads only cross-reacted with those of two genetically closely related species, B. mallei and B. thailandensis (previously classified as non-pathogenic arabinose-negative B. pseudomallei). However, this system could distinguish other closely related species from B. pseudomallei. This assay is able to detect significantly high levels of anti-LPS antibodies of B. pseudomallei in serum from patients with culture-proven melioidosis.
Subject(s)
Antibodies, Bacterial/analysis , Burkholderia pseudomallei/immunology , Fluorescent Antibody Technique, Indirect/methods , Antibodies, Bacterial/immunology , Burkholderia pseudomallei/classification , Enzyme-Linked Immunosorbent Assay/methods , Lipopolysaccharides/immunology , Melioidosis/diagnosis , Melioidosis/microbiology , Microspheres , O Antigens/immunologyABSTRACT
In the last few years, many attempts have been made to use conserved gene sequences for identification and for phylogenetic studies of Staphylococcus species. In an effort to identify a more reliable approach, a dnaJ gene sequence-based database was created. In this study, an approximately 883 bp portion of the dnaJ gene sequence from 45 staphylococcal type strains was compared with 16S rRNA and other conserved gene (hsp60, sodA and rpoB) sequences available in public databases. Nucleotide sequence comparisons revealed that the staphylococcal dnaJ gene showed higher discrimination (mean similarity 77.6 %) than the 16S rRNA (mean similarity 97.4 %), rpoB (mean similarity 86 %), hsp60 (mean similarity 82 %) and sodA (mean similarity 81.5 %) genes. Analysis of the dnaJ gene sequence from 20 Staphylococcus isolates representing two clinically important species showed <1 % sequence divergence. Phylogenetic data obtained from the dnaJ gene sequence were in general agreement with those of 16S rRNA gene sequence analysis and DNA-DNA reassociation studies. In conclusion, the dnaJ gene sequence-based assay is an effective alternative to currently used methods, including 16S rRNA gene sequencing, for identification and taxonomical analysis of Staphylococcus species.
