What is an endotoxin?

An endotoxin is defined as a component of the outer membrane of Gram-negative bacteria. Specifically, it refers to lipopolysaccharides (LPS) found in the cell wall of these bacteria. When Gram-negative bacteria die or are damaged, endotoxins are released into the surrounding environment, which can trigger strong immune responses in the host. This response often includes fever, inflammation, and can lead to more severe complications such as septic shock.

Understanding the nature of endotoxins is crucial in microbiology and infectious disease, as they differ significantly from exotoxins, which are actively secreted by bacteria and often have specific, targeted effects on host cells. The other choices relate to aspects of toxins or components of other microorganisms but do not accurately define endotoxins in the context of bacteriology.