digestive system Flashcards
GI tract includes
mouth
pharynx (throat)
esophagus
stomach
small and large intestine
accessory sturctures of the digestive system include
teeth and the tongue
salivary glands
liver
gallbladder
pancreas
staphyloccoal food poisoning
Staphylococcal Enterotoxicosis
*bacterial INFX.
enterotoxin produced by S. aureus
outgrows most bacteria in high osmotic pressure (salt) and high temperature.
coagulates blood plasma (type A).
toxin is not killed through boiling and are produced by allowing the organism to incubate in food - TEMPERATURE ABUSE.
caused: when food is prepared incorrectly.
phage typing
traces where the toxin came from
Shigellosis/Bacillary Dysentery
*bacterial INFX.
caused by the genus Shigella
- facultative anaerobe and gm(-)
*multiplies inside the cell!
- S. sonnei
- S. dysenteriae
residents of the intestinal tract of humans, apes, and monkeys.
closely related to E. coli.
treatment: fluoroquinolones and oral rehydration
symptoms: blood or mucus in stool, abdominal cramps, fever.
small infectious dose!
Shigellosis: S. sonnei
causes mild dystenery
“travelers diarrhea”
Shigellosis: S. dysenteriae
causes SEVERE dysentery.
- prostration: extreme fatigue
caused by an unusual viral toxin
Shiga toxin S. dysenteriae!
The least common INFX in the US
cause ulceration of the intestinal wall.
Salmonellaosis/Salmonella Gastroenteritis
caused by Salmonella enterica
associated with chickens, eggs, and reptiles!
invades the intestinal mucosa and multiplies WITHIIN the vesicle of a cell.
it then enters lymph, evades phagocytes, and replicates in macrophages.
symptoms: fever, nausea, pain, cramps, diarrhea.
bacterium can survive in the abdomen
detected through stool sample.
treatment: oral rehydration therapy
Salmonellosis/Thyphoid Fever
caused by Salmonella serotype Typhi
spread by human feces.
rare in the US due to sanitation.
the bacteria is spread throughout the body in phagocytes, releasing organisms in the blood stream.
symptoms: high fever, headache, ulceration in intestinal wall.
chronic carriers harbor the organism in the gallbladder!
treatment: ceftriaxone (cephalosporin) and azithromycin.
chronic carriers require weeks of treatment.
Cholera
caused by vibrio cholera.
curved gm(-) rod.
associated with oysters, salty waters, and natural disasters.
cholera toxin: causes the host to secrete 12-20 liters of electrolytes and water rapidly per day. “rice water stools”.
causes: shock, collapse, organ failure, and death.
treatment: IV fluid replacement.
! increases when sanitation and sewage disposal systems are compromised.
ex. Haiti outbreak.
Escherichia coli gastroenteritis
caused by E. coli
mobile genetic elements can turn normal E. coli into a highly adaptive pathogen causing multiple diseases.
can secrete toxins into the body.
urinary tract, bloodstream, and CNS can be affected.
Enterohemorrhagic E. coli (EHEC): adheres to the epithelial wall and destroys surface microvilli, important for absorption, causing the formation of a pedestal-like projection that may help spread adjacent cells.
main carriers: cattle!
Campylobacteriosis: Campylobacter Gastroenteritis
caused by Campylobacter jejuni
gm (-) microaerophile, curved/spiral.
associated with poultry!
the leading cause of foodborne illness in the US!
common in the intestines of POULTRY. 60% of cattle excrete organisms in feces and milk.
symptoms: fever, cramping, abdominal pain, diarrhea, dysentery.
1 in 1000 cases can lead to a severe neurological disorder: Guillain-Barre syndrome.
Helicobacter pylori: Peptic Ulcer Disease
caused by H. pylori
causes: gastric ulcers and duodenal ulcers.
treatment: a combination of 2-3 ABX and a PPI (protein pump inhibitor), which drops acid secretion!
takes 3-14 days to treat the microbe and to reduce stomach acid.
Clarithromycin and Amoxicillin +
either: Nexium, Prilosec, Serid, or Prevacid.
Clostridium difficle-associated diarrhea
caused by C. difficile
gm (+) anaerobe, endospore-forming, and found in healthy adults.
exotoxins produced cause symptoms ranging from mild diarrhea to life-threatening colitis which can result in ulceration and perforation (rupture/hole) in the cell wall.
highest mortality in the elderly
treated with Vancomycin.
Rotavirus and Norovirus
*viral INFX
- Rotavirus: very common in children along with Rhinovirus!
low mortality, but is higher in underdeveloped countries since rehydration therapy isn’t available.
acquired immunity in the US since places like daycares are more common making it less common in adulthood.
symptoms: lower fever, diarrhea, vomiting.
prevented with a live oral vaccine.
1. RotaTea (RV5): 3 doses (1m, 4m, 6m)
2. RotaTrix (RV1): 2 doses (2m and 4m)
- Norovirus
fecal-oral transmission
low INFX dose
causes diarrhea and vomiting.
