ANTIBIOSIS OF BURKHOLDERIA UBONENSIS AGAINIST BURKHOLDERIA PSEUDOMALLEI, THE CAUSATIVE AGENT FOR MELIOIDOSIS

Melioidosis, caused by Burkholderia pseudomallei, is an enigmatic infectious disease that afflicts individuals in many tropical and developing regions. Treatment is hampered by the organism's innate antibiotic resistance and the disease's non-pathognomic presentation. Recently, added attention has been given to this organism due to its classification as a potential biowarfare agent. Therefore, methods of preventing acquisition of infection are needed. We investigated antagonism between Burkholderia spp and B. pseudomallei derived from the same ecological niche in a melioidosis endemic region in Papua New Guinea. Isolates of environmentally derived non-pseudomallei Burkholderia spp (n=16) were screened for antibiosis against 27 B. pseudomallei isolates. Three isolates subsequently identified as B. ubonensis produced specific antagonistic activity against all B. pseudomallei isolates tested. The antagonistic compound in a cell-free state was obtained from a representative producing strain, with subsequent biological characterization revealing a pepsin sensitive peptide moiety consistent with a bacteriocin-like compound. To our knowledge, this is the first report of antagonistic activity demonstrated by near-neighbor Burkholderia against B. pseudomallei. This antagonism may be important in the micro-ecology of B. pseudomallei, and could also have application in the biocontrol of this pathogen.