Virulent forms of B. anthracis, the causative agent of anthrax, are more likely to be surrounded by a capsule. This capsule is a polypeptide, composed of a polymer of glutamic acid, and is a unique feature of B. anthracis. Lipopolysaccharides (LPS/endotoxin) are unique to gram-negative bacteria (B. anthracis is a gram-positive rod). In addition, whereas B. anthracis is associated with both teichoic acid (cell wall) and a potent exotoxin, these are not unique features of this bacterium. Other gram-positives (i.e., staphylococci) release exotoxins and have teichoic acid in their cell walls.