In: Biology
Microbes have several mechanisms of pathogenicity. Contrast pathogenicity and virulence. Describe five virulence factors found in microbes and explain how each affects the establishment and success of disease.
Pathogenicity is an absolute qualitative ability of an infectious agent to cause disease, while virulence is the quantitative relative capacity of a pathogen to invade or infect host cells.
The major virulence factors includes adhesins, toxins, surface receptors, capsule, and exoenzymes.
Adhesins are cell-surface components or appendages of microbes: bacteria to facilitate bacterial adhesion or adherence to other cells or to inanimate surfaces. The expression of these adhesins at different phases of infection play most important role in adhesion based virulence.
The toxins allow the pathogens to invade host tissue and cause them damage. The toxins: endotoxin and exotoxins can be immunogenic or cause intense inflammations.
Surface receptors are usually glycoproteins that binds to the host cell membrane with having the property of adherence and virulence, while the exoenzyme, or extracellular enzyme, is an enzyme that is secreted by a cell and functions outside that cells.
Capsule is a virulence factor due to it's ability to cause disease by preventing phagocytosis, and it can also protect cells from engulfment by eukaryotic cells: macrophages.
Each of these five virulence factors found in microbes acts differently, but are essential to infect host cells.