Food-poisoning bacteria use enzymes to escape the cells they infect freeing them to infect even more
Species of Vibrio bacteria are a major cause of food poisoning in humans, commonly acquired through the consumption of raw shellfish or contaminated water. Infection with the bacteria leads to nausea, stomach cramps, vomiting and diarrhoea as the bacteria invade the cells lining the intestine and multiply rapidly. While researchers have figured out that Vibrio uses needle-like appendages (known as the type III secretion system) to enter intestinal cells, how the bugs get back out was a mystery. Now, it’s been discovered that, inside the cell (highlighted in red), the bacteria (green) secrete fat-modifying enzymes called lipases, which alter the cholesterol components of the cell’s plasma membrane, weakening its structure. This allows the jostling multitude of bugs to eventually push their way out. The liberated bacteria are then free to invade more intestinal cells, or to escape the body and, if not properly destroyed, lie in wait for another victim.
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