13. diseases of the digestive system Flashcards
this is a medical condition characterized by inflammation of the gastrointestinal tract that could involve both the stomach (“gastro”) and/or the small intestine (“entero”) resulting in some combination of diarrhea, vomiting, abdominal pain and cramping
gastro-enteritis
globally, most cases of gastroenteritis are caused by ________; a virus transmitted by the fecal-oral route and capable of causing severe diarrhea
rotavirus
this is a large family of gram-negative bacteria, many members of this family are causative agents for gastroenteritis
enterobacteriacecae
this type of bacteria which is gram-negative and rod shaped is a common member of the normal microbiota of the colon; most strains are harmless, but some serotypes are pathogenic and can cause serious food poisoning in humans and other species
escherichia coli (e. coli)
how many groups of pathogenic E.coli are there?
six
this is a pathogenic group of e.coli; it is the most common cause of traveller’s diarrhea. it attaches to the intestinal wall and produces a heat stable enterotoxin which induces hyper secretion of electrolytes and water into the intestinal lumen which causes diarrheal illness. can be spread from hand to mouth or through contaminated food/water
enterotoxigenic e.coli (ETEC)
what are some symptoms if ETEC/traveller’s diarrhea is present?
water diarrhea, abdominal cramps, low fever
T/F: the disease that ETEC causes is usually self limiting
true
what may be used to treat ETEC if needed?
antibiotics: fluoroquinolone, doxycycline and rifaximin
this is a pathogenic group of e.coli; it is an intracellular invasion into intestinal epithelial tissue, and is similar to shigellosis disease. virulence factors of this e.coli are carried on a large plasmid
enteroinvasic e.coli (EIEC)
what are some symptoms if EIEC is present?
diarrhea, chills, cramps and fever -> usually self-limiting
this is a pathogenic group of e.coli; strains cause a kind of cell damage called effacing lesions by attaching to the brush border of intestinal epithelial cells using an adhesion factor known as intimin which results in destruction of brush border microvilli (hemorrhagic colitis)
enter-pathogenic E. coli (EPEC)
EPEC has __________ encoding for virulence factors such as Tir protein that triggers rearrangement of host cell actin from microvilli
pathogenicity island genes
what are some symptoms if EPEC is present?
fever, vomiting, and diarrhea can lead to severe dehydration. can cause fatal diarrhea especially in infants and those in less developed countries. tx is similar to ETEC
this is a pathogenic group of e.coli; strains adhere to epithelial cells in localized regions, forming clumps of bacteria with a stacked brick appearance. can also produce several plasmid-encoded toxins that cause diarrhea, especially in children. it is the second most common cause of travellers diarrhea
Enteroaggregative e.col (EAEC)
this is a pathogenic group of e.coli; the most dangerous kind of strains, which is capable of causing epidemics. produces a shiga-like toxin (or verotoxin). can cause diseases ranging from relatively mild to life threatening
enterohemorrhagic (EHEC) or shiga toxin-producing e.col (STEC)
EHEC/STEC has a strain known as ______ which has been responsible for several recent epidemic outbreaks
O157:H7
what are some symptoms if EHEC/STEC is present?
bloody diarrhea with severe cramping, but no fever, it can lead to hemorrhagic colitis and profuse bleeding
this is a group of gastrointestinal infections caused by 4 Shigella (rod-shaped, gram-negative) species; these species invade intestinal epithelial cells and then multiply inside the tissue, the epithelium and the M cells of the Peyers patches in the intestine become ulcerated and start loss of fluid
Shigellosis (bacillary Dysentry)
what 4 shigella species are responsible for causing shigellosis?
Shigella Sonnei, Shigella flexneri, Shigella boydii and Shigella dysenteriae
how is shigellosis spread?
hand to mouth or through contaminated food/water
what are some symptoms of Shigellosis?
- fever
- watery diarrhea (may also contain pus, mucus, and/or blood)
- in severe cases: ulceration of the mucosa, dehydration and rectal bleeding
________ type 1 produce Shiga toxin, which targets the endothelial cells of the small blood vessels in the intestines and later targets the glomerular endothelium in the kidneys leading to hemolytic uremic syndrome (HUS) and kidney failure
S. dysenteriae
T/F: antibiotics are never indicated for Shigellosis
false - severe cases may require antibiotics such as ciprofloxacin and azithromycin
