In microbiology, bacterial toxins are molecules secreted or displayed by bacteria that alter host-cell metabolism and account for many disease symptoms, in contrast to viral infection, which involves few identified toxins. Toxins are classified by mechanism into exotoxins (secreted A-B subunit proteins that enter host cells and disrupt intracellular processes), type III secretion-system toxins (directly injected into host cells), surface-acting toxins (pattern-recognition-receptor agonists, pore-forming toxins, superantigens), and exoenzymes that degrade the extracellular matrix; endotoxin (lipopolysaccharide) is a distinct gram-negative cell-wall component recognized by innate pattern-recognition receptors that triggers dose-dependent cytokine-mediated host responses.
In microbiology, bacterial toxins are molecules secreted or displayed by bacteria that alter host-cell metabolism and account for many disease symptoms, in contrast to viral infection, which involves…