Production and molecular composition of Burkholderia pseudomallei and
Burkholderia thailandensis biofilms
Biofilm communities cause many infectious diseases. Biofilms are diverse
microbial species found either attached to a surface or aggregated into
an extracellular matrix. Bacteria form biofilms as a default mode of
growth or as a response mechanism to environmental conditions like
stress. As such, biofilm strains are increasingly virulent causing a
wide variety of chronic persistent diseases, are typically
antibiotic-resistant and known to improve host mortality rate. Most
biofilms contain polysaccharides, proteins, extracellular DNA (eDNA),
RNA, and water. Determining and quantifying the major components of a
biofilm may indicate an appropriate treatment for biofilm eradication.
Burkholderia pseudomallei is a Gram-negative, motile bacillus typically
found in surface water and/or soil in endemic regions. It is the
etiologic agent of melioidosis and is capable of forming both surface
adherent and air-liquid interface biofilms (pellicle) in broth cultures.
This study evaluates the components of established biofilms using B.
pseudomallei and Burkholderia thailandensis, a closely related
nonpathogenic species. Using assays, fluorescent dyes and microscopy, we
quantified the major components of biofilms produced by five genetically
related B. pseudomallei strains and compared them to B. thailandensis
E264. Our data show that biofilm produced by the B. pseudomallei 1026b
derivatives and B. thailandensis E264 significantly differ. The
molecular composition of the surface adherent biofilm is similar to the
molecular composition of the air-liquid pellicle. Finally, the eDNA
quantity biofilm produced by JW270 which bears a CPS I deletion, is
significantly increased in comparison to 1026 and Bp82 biofilm.