Term
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Definition
| Increased fluid content in the feces; increased volume of feces; increased frequency of elimination; increased dehydration; increased electrolyte loss; increased GI motility. |
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Term
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Definition
A disease characterized by frequent, watery stools containing blood and mucus.
This is an extreme case of diarrhea. |
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Term
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Definition
| Inflammation of the epithelial lining of the small and large intestines |
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Term
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Definition
| Inflammation of the epithelial lining of the stomach and intestines |
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Term
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Definition
| Affect cells linikng the GI tract |
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Term
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Definition
The ingestion of an overabundance of pre-formed bacterial toxins.
The body has a rapid response rate for intoxication. |
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Term
| Defense Mechanisms of the GI |
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Definition
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Term
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Definition
GRAM NEGATIVE
- ALL: Endotoxin in cell walls
- 5 groups associated with gastroenteritis
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Term
| 5 Major Groups of E. coli |
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Definition
Organism Site Disease
1)Enteropathogenic SI Infant, traveler’s diarrhea UD
2)Enterotoxigenic SI “ UD (underdeveloped county)
3)Enteroaggregative SI “ UD
4)Enterohemorrhagic LI Watery to grossly bloody D
5)Enteroinvasive LI Dysentery UD
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Term
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Definition
Produces a very severe toxin. It is similar to the shigella toxin in its severity.
As few as 100 bacteria can produce severe diarrhea. |
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Term
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Definition
Invades the epithelial lining.
Endocytosis and disrupts cell function.
Can breakdown lining of epithelium and cause dysentery (severe diarrhea).
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Term
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Definition
- Bacillus even though it looks coccus (cross section).
- The E. coli upset the SA of the small intestine- affecting absorption.
- This type of E. coli isn’t invasive, it stays on the surface and interrupts absorption.
- It also doesn’t produce endotoxins- is just a physical presence.
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Term
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Definition
Fimbrae are around a layer of toxins being released around the bacteria.
This strain releases a lot of endotoxins.
When the toxin is released, it affects the SI and causes a change of function.
It causes the SI to release a lot of prostaglandins, which increases contractions (peristalsis) to get rid of the bacteria.
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Term
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Definition
The surface of the SI is being destroyed.
The aggregation of bacteria irritates the lining and makes it produce a lot of mucus, which interferes with absorption and provides a breeding ground for more bacteria. |
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Term
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Definition
GRAM NEGATIVE
- Bacillus; comma shape
- Microaerophilic
- Flagellar motility
- Contaminated food and milk
- Undercooked chickens
- BLOODY STOOL from damage to mucosa of the jejunum
- MOST COMMON CAUSE OF BACTERIAL GASTROENTERITIS
- Self limiting
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Term
Salmonella spp.
(Salmonellosis)
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Definition
GRAM NEGATIVE
•Facultative anaerobe
•Most common cause of food-borne diarrhea in most developed countries
•Humans acquire from poultry, meat, eggs, milk
•Usually an acute infection and self-limiting except in the young or old (12-36 h recovery)
Ruffle the surface of the SI to get into the gut
Ssp. Refers to a large group that may or may not be in the same species.
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Term
| How many serovars/serotypes (serological varieties) of Salmonella enterica have been recognized? |
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Definition
2400
Most cases of salmonellosis are casued by S.enterica |
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Term
| What is the passage of salmonella through the body? |
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Definition
o Invade epithelial cells of the ileocecal region and migrate to the lamina propria (thin CT layer). Can multiply in lymphoid follicles.
o Good that it is confined to the GI tract (doesn’t become systemic).
o Many species and serotypes, but S. enteric important for human infection.
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Term
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Definition
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Term
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Definition
GRAM NEGATIVE
- - Facultative anaerobe, curved.
- - Single flagellum (vibro=vibrates), virulence factors such as an enterotoxin.
- - Strictly a human pathogen, causing cholera.
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Term
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Definition
o Due to inadequate drinking water and sewage handling or asymptomatic humans, shellfish, or contaminated food.
o Colonization of SI, enterotoxin causes rice water stools (epithelial lining comes out in chunks).
o Severe diarrhea causes dehydration and person may drink more contaminated water (major cause of death in the world).
o ORT- oral rehydration therapy to prevent fluid and electrolyte balance.
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Term
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Definition
•4 species cause bacillary dysentery (shigellosis)
•GRAM NEGATIVE, bacilli
•Facultative anaerobe, non-motile
•Invades ileum, colon epithelial cells; rarely invade bloodstream
• Exotoxin (Shiga toxin)
•Usually transmitted via poor sanitation, overcrowding
Destroys immune cells, but remains localized in the small intestinal lining. If the toxin is secreted in large enough amounts it can cause adverse effects.
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Term
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Definition
Attached to intestinal epithelium
Damage transport mechanisms in the intestines
Damage reabsorption --> dehydration
Cause of most viral gastoenteritis
Fecal/Oral transmission
If no re-infection then it lasts about 1 week |
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Term
| Rotavirus Diarrhea Mechanism |
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Definition
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Term
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Definition
GRAM POSITIVE
Facultative anaerobe
Enterotoxins act as superantigens and bind to MHC...leads to T-cell stimulation
Heating can kill bacteria, toxins survive
Intoxication --> can get a very high bacterial load and a high load of toxins |
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Term
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Definition
GRAM POSITIVE
ANAEROBIC
Common pathogen in birds, mammals, and soil
3 Types:
Foodborne
Infant
Wound
VERY POTENT |
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Term
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Definition
Exotoxin
(Botulinum toxin)
Produced in gut after bacterium ingested or from improperly canned or reheated foods
Absorbed from the gut to the blood |
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Term
| Where is the site of action for Botulism toxin? |
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Definition
NERVE SYNAPSES
Blocks nerve impluses (Ach release) at the neuromuscular junctoon |
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Term
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Definition
GRAM NEGATIVE
Spiral
Microaerophilic bacteria
Gastric and duodenal ulcers
Adhesins, urease, cytoxins disrupt stomach and SI mucosa
Produces urease --> ammonia which neutralizes the acidity of the protective mucous layer --> erosion of the wall |
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Term
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Definition
•Gram-negative bacillus
•Facultative anaerobe
•Pathogen not found in animals; only spread by human fecal/oral route
•Pathogens multiply in phagocyctic cells, spread to liver, spleen, and lyse, becoming blood-borne
•Frequent cause of death in parts of world with poor sanitation
•Much more serious than salmonellosis
Can become chronic carriers.
NOT FROM ANIMALS
FECAL/ORAL
Typhoid Fever
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Term
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Definition
•Single-stranded RNA, can be grown in cell culture
•Picornaviridae
•Hepatovirus
•Spread by fecally contaminated food, water, hands, or by anal intercourse
•Multiplies in the intestinal epithelium, spreads to liver, kidneys, spleen
•Usually no liver damage...will cause it, but not permanent
Can affect hepatocytes and also kupffer cells: fixed macrophages/phagocytic cells of the liver
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Term
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Definition
Amoebic Dysentery
Giardiasis |
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Term
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Definition
Causes amoebic dysentery or amoebiasis: mild to severe diarrhea, with blood, mucus, pus in stools
•Food or water contaminated with cysts; stomach acids don’t affect cysts
•Worldwide but common in tropical countries
- Trophozytes
- There is an active feeding stage and an incysted stage
- Stomach acids cannot affect cyst
- In the SI the cyst will dissolve and becomes active
- Immune system may be able to get rid of it
- If you keep ingesting it, can become systemic and go to brain and lungs…more severe
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Term
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Definition
Like Entamoeba, mild to severe diarrhea and cysts and trophozoite forms
Adhere to microvilii of SI
Most commonly diagnosed intestinal protozal-parasite in US
Adheres to microvilli and destroys epithelium and a person can live with it but have chronic diarrhea
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Term
| Helminth (nematode) Infections |
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Definition
Ascariasis
Hookworm
Enterobiasis |
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Term
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Definition
- Ascariasis; roundworm infection
- Spread via a fecal/oral route
- Adult worms migrate
- Usually not severe symptoms but can cause duct blockage
- Feeds on digested food
Lifecycle:
-2. fertilized eggs
-2-3. eggs further develop into a larvae …still has egg casing and if someone ingests it, it will mature in small intestine that is able to invade the CV system which explains why the arrow jumps to the lungs --> trachea --> pharynx --> swallowed --> esophagus --> stomach --> small intestine -->mature into adult à mate and produce unfertilized eggs
-If destroyed in the gut then it gets rid of it
-If maturing into larger larval forms they can migrate to other parts…like out the nose and anus and that is how they are diagnosed
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Term
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Definition
Once common in the SE US
Hookworm attaches to intestinal wall, feeding on blood, tissue (not food); anemia
Does NOT feed on digested food
Teeth to hook onto intestinal wall and feed in BLOOD and TISSUE --> leads to anemia
Similar lifecycle as ascaris
The eggs are excreted in feces and larval form hatches in nature (i.e. sand) and the larval form penetrates in the foot and becomes systemic and goes to the lung then up trachea and swallowed and mature in SI and lifecycle repeats
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Term
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Definition
•migrates out of anus to lay eggs; if ingested, larvae hatch in SI
•Best detected with a “Graham sticky tape method”
Most common helmith infection in US
Crawls down to anus to lay eggs
PINWORM DISEASE
Hatch in SI and mature in intestines
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Term
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Definition
Tapeworms
1.Adult worm in intestines of humans, eggs excreted in feces
2.Eggs ingested by grazers and hatch into larvae
3.Humans eat undercooked meat, larvae develop into adults that attach to walls of SI
Humans ingest improperly cooked meat --> passed in feces --> eggs can be ingested by intermediate host --> eggs will hatch in the hosts SI and larvae migrates to the muscles --> ingested by humans --> mature in SI --> passed --> continue
Attaches to intestinal wall and has teeth and feeds on blood and tissue of the host and interfere with digestion and blocks absorption
Intermittent diarrhea
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Term
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Definition
•A common mold, Aspergillus flavus, produces a mycotoxin, aflatoxin.
•Many foods, particularly peanuts and corn
•May contribute to liver CA and cirrhosis
Fungal disease of GI tract
The most common natural toxin known to be a potential carcinogen because can lead to liver cancer…must be ingested in large amounts and continually
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