Abstract:
Burkholderia pseudomallei is the cause of melioidosis, a fatal tropical infectious disease, which was reported to have a high rate of recurrence even when an intensive dose of antibiotics was used. The biofilm formation is believed to be one of the possible relapse causes because of the ability to increase drug resistance. Extracellular polymeric substance (EPS) in biofilm has been reported to be related to limitation of antibiotic penetration in B. pseudomallei. However, the mechanisms through which that biofilm creates a restricting diffusion to antibiotics remains unclear. In this study, the researcher presented a correlation between exopolysaccharide production in biofilm matrix and antibiotic resistance in B. pseudomallei by using bpsI, ppk, rpoN2 and rpoS mutant strains. CLSM revealed a reduction of the exopolysccharide production and disability of the micro-colony formation in B. pseudomallei mutants, which paralleled the antibiotic resistance. Different ratios of carbohydrate contents in exopolysaccharide of the mutants was detected, although they had the same components; glucose, galactose, mannose, and rhamnose with no detectable peak found in bpsI mutant. These results indicated that the correlation between these phenomenal in B. pseudomallei biofilm at least resulted from exopolysaccharide which may have been under the regulation of bpsI, ppk, rpoN2 or rpoS genes.