BIOL 2905 Study Guide - Final Guide: Antimicrobial Resistance, Exotoxin, Lipopolysaccharide
14 Dec 2016
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Norton animation; virulence factors listeria infectionmode of entry. Listeria species include enteric pathogens such as listeria monocytogenes, that may contaminate foods such as cheese and sauerkraut. When listeria enters the digestive tract, the immune system mounts an attack. Macrophages engulf the bacteria by phagocytosis: the internalized vesicle is called a phagosome. Normally, a phagocytized bacterium would be digested by the macrophage, but listeria releases a toxin that lyses the phagosomal membrane, allowing the bacterium to move freely through the cytoplasm. Inside the cell, bacteria have a rich medium for growth and reproduce quickly: because they are hidden inside cell, they can evade the antibodies of the immune system. The growth of the actin tail can force a bacterium into the the plasma membrane, creating a protrusion that a neighboring cell can take up by phagocytosis: new cell = new host to listeria and continues infection. Many bacteria produce toxins, enzymes, and pigments.
