Fig 8. Biofilm assay with B. mallei recombinant and WT strains.

B. mallei strains were cultured in the wells of PVC microplates, stained with crystal violet, washed with deionized water, and the wells were photographed. The arrow shows biofilm formation, which was quantitated by extracting crystal violet with methanol and measuring absorbance at 570 nm. The results are shown in parentheses and are expressed as the mean (± standard error) absorbance. The asterisk indicates that the increase in biofilm formation by bacteria carrying pBpaB is statistically significant (P values < 0.05, Mann-Whitney test).