Differential cell surface properties of vegetative Bacillus

The genus Bacillus encompasses a wide range of species which display varying pathogenic abilities. The hydrophobicity of a range of Bacillus species was determined to evaluate the correlation between bacterial hydrophobicity and pathogenicity. Bacterial adhesion to hydrocarbon assays were used to determine the hydrophobicity of various Bacillus species. Significant differences in the hydrophobicity of vegetative Bacilli were found. Specifically, vegetative Bacillus anthracis or Bacillus thuringiensis cells were highly hydrophobic whereas Bacillus cereus or Bacillus subtilis were only slightly hydrophobic using this test. Cell adhesion assays using A549 or J774 cells were used to demonstrate a correlation between the bacterial hydrophobicity profiles with the ability to adhere to the mammalian cell lines. The ability of Bacillus species to adhere to mammalian cell lines correlates with the hydrophobicity of the bacteria and also correlates with the relative pathogenicity of some of the Bacillus species tested. This work suggests that study of the physical-chemical properties of vegetative cells could inform future approaches for the rapid identification and discrimination of potentially pathogenic Bacilli.