Micro| Bacterial Toxins

3.02 Bacterial Toxins   Microbiology review for the USMLE Step 1 Exam.   Bacterial toxins are harmful compounds produced by bacteria that cause damage to the host Exotoxins are toxins that are actively secreted by some species of gram positive and gram negative bacteria Examples of exotoxins include botulinum toxin, Corynebacterium diphtheriae toxin, and cholera toxin Endotoxins are toxins that are contained within the cell wall of gram negative bacteria and are released when the bacteria are lysed or fragmented Structurally, endotoxins consist of the O antigen, the core oligosaccharide, and Lipid A, with the Lipid A component being responsible for most of the toxicity Endotoxins are less virulent and more heat stable than exotoxins, and are usually contained in the bacteria's own genetic material rather than on a plasmid