Week 7 Flashcards
The term gastroenteritis is applied to syndromes of diarrhea or vomiting that tend to involve _____ infection of the ___ or ____ of the ____
Non-inflammatory
Upper small bowel
Inflammatory
Colon
Who are more likely to get diarrhea, children or the elderly?
Children
What is the best way to prevent getting diarrhea?
Washing your hands!
What is the #1 anaerobic bacteria in the normal enteric microflora?
Bacteriodes fragilis
This plays an important role in the development of the immune system
What is the #1 facultative bacteria in the normal enteric microbiota?
E. Coli
What are the three different types of microbial virulence factors?
Toxins
Attachement
Invasiveness
What are the three different types of toxins that may cause diarrhea?
Neurotoxins
Enterotoxins
Cytotoxins
Neurotoxins are usually ingested as ____ that cause enteric symptoms
Preformed toxins
Neurotoxins have their effect on the ____ rather than directly on the intestine
Central autonomic nervous system
Name three bacterial species that produce neurotoxins
**clostridium botulinum
Bacillus cereus
Staphylococcus aureus
How do enterotoxins work?
Have a direct effect on the intestinal mucosa to cause fluid secretion
Cause an alteration in the metabolic activity of the intestinal epithelial cells
Results in an outpouring of electrolytes and fluid, primarily in the jejunum and upper ileum
Name four bacteria that produce enterotoxin
**vibrio cholerae
Non cholera vibrio spp.
E. Coli
Salmonella
What are cytotoxins responsible for? Where do they primarily affect? Cytotoxins often result in…
Responsible for mucosal destruction
Often results in inflammatory colitis
Happens almost exclusively in the colon
Generally referred to as dysentery
Name some species that produce cytotoxins
**shigella dysenteraie
S. Aureus
C. Perfringens
E. Coli
C. Difficile
Why is “attachment” a virulence factor?
They destroy the ability of cells to participate in normal secretion and absorption
Name four bacterial species that have attachment virulence factors
E. Coli
Giardia lamblia
Cryptosporidium
Isospora
Name some species that have the ability to invade the GI tract
Shigella
E. Coli
Vibrio
What percentage of food borne illnesses are due to bacteria and viruses? What about toxins and parasites? What species are the leading cause of bacterial food borne illnesses in the U.S?
84
16
Campylobacter jejuni and Salmonella
What foods are you most likely to get food poisoning from staphylococcus aureus?
Meats and milk products
Often because food handlers have a staph infection and get it in the food
Where is C. Perfringens likely to be found?
Lives in the soil but can grow on meats
When the spores germinate, it releases toxin
What foods are you most likely to get food poisoning from salmonella? How long does it take for onset?
Poultry, eggs, meats, milk, produce
Takes about 24 hours or longer because it must get to the small intestine.
True or false… Shigella does not survive well in the environment and must be transferred from person to person. It is an invasive pathogen and causes dysentery and fever
True
What food sources are you most likely to pick up shigella?
Produce
(But mostly fecal oral route)
Note that this bacteria is closely retaliated to E.coli, which is why it can pick up some E.coli genes
Where are you most likely to pick up campylobacter?
Water
Raw milk
Poultry
Pets
Note that this is one of the most common causes for food poisoning in the US
What is the most common vibrios (that is not vibrio cholera) to cause food poisoning? What is this bacteria associated with?
Vibrio parahaemolyticus
It is halophilic so it is associated with salt water and sea food (especially raw or uncooked seafood)
Describe bacillus cereus
Very widespread (you can find it about anywhere)
Spore forming
Found especially in rice, meat, and in dirt (on vegetables)
If you cook it, then cool it down, spores will form
Aeromonas Hydrophila is associated with…
Fresh water
Its like the fresh water version of vibrio parahaemolyticus
Vibrio cholera is usually found where?
If contaminated water. It doesn’t survive freely in water, it lives on microscopic crustations called coprapods. This means that it is easy to filter out vibrio cholera from water
What is SLT E.coli? What foods is it most likely to be present in?
It is E.coli that has taken up a shigella toxin gene
It is associated with hamburger because this meat has a lot more surface area for the microbe to grow on
Is listeria monocytogenes gram positive or gram negative? What foods is it most likely to be found in? This particular pathogen is especially detrimental to whom?
Gram positive rod.
Mostly found in milk products
Danger to fetuses because this bacteria can cross the uterus
What is a hysteria reaction?
Vomiting due to a psychological reason (such as watching someone else vomit).
This reaction occurs within minutes
What bacterial species has an incubation time of minutes-hours?
Bacillus cereus
Staphylococcus aureus
and chemicals, heavy metals, and shellfish toxins
