Flashcard Set: MICR290 - Chapter 23 (Digestive System Infections)

Q: What are the functions of the digestive system?
A: Digests food, absorbs nutrients and water, eliminates waste.

Q: What does the GI tract include?
A: The pathway from mouth to anus.

Q: What do accessory digestive organs do?
A: Help with mechanical digestion or secrete digestive fluids.

Q: What microbiota are found on the tongue and teeth?
A: Viridans streptococci.

Q: Are the esophagus, stomach, and duodenum colonized by microbes?
A: No, they are mostly microbe-free due to peristalsis and fast food movement.

Q: What part of the digestive tract has the most microbes?
A: The lower small intestine and colon (with microbial antagonists).

Q: What causes dental caries?
A: Streptococcus mutans.

Q: What virulence factors are involved in tooth decay?
A: Dextran and pili help form biofilms on teeth.

Q: What causes periodontal disease?
A: Porphyromonas gingivalis, which uses proteases to break down gums.

Q: How are cavities treated and prevented?
A: Treat by filling; prevent with good oral hygiene.

Q: What causes peptic ulcers?
A: Helicobacter pylori.

Q: What are the virulence factors of H. pylori?
A: Flagella (motility), adhesins, urease (neutralizes acid), toxins (damage cells).

Q: How is H. pylori transmitted?
A: Fecal-oral route.

Q: How are ulcers diagnosed and treated?
A: Diagnosed by x-ray and clinical tests; treated with antimicrobials and acid blockers.

Q: What is bacterial gastroenteritis?
A: Inflammation of stomach or intestines caused by bacteria.

Q: What are common symptoms of bacterial gastroenteritis?
A: Nausea, vomiting, diarrhea, cramps, and abdominal pain.

Q: What is dysentery?
A: Severe diarrhea with blood and mucus.

Q: What causes cholera?
A: Vibrio cholerae.

Q: What does cholera toxin do?
A: Causes cells to secrete electrolytes and water, leading to watery diarrhea.

Q: What is a key sign of cholera?
A: "Rice-water" stool.

Q: How is cholera treated and prevented?
A: Rehydration and tetracycline; prevent with hygiene and vaccines.

Q: What causes Campylobacter diarrhea?
A: Campylobacter jejuni.

Q: What are the virulence factors of C. jejuni?
A: Adhesins, cytotoxins, and endotoxins.

Q: What food is commonly linked to C. jejuni?
A: Poultry.

Q: What causes antimicrobial-associated diarrhea?
A: Clostridioides (formerly Clostridium) difficile.

Q: What makes C. difficile dangerous?
A: It forms endospores and releases two toxins that cause inflammation and colitis.

Q: How is C. difficile diagnosed and treated?
A: Toxin detection in stool; treated with antimicrobials and stopping unnecessary antibiotics.

Q: What causes salmonellosis and typhoid fever?
A: Salmonella enterica.

Q: How is typhoid fever spread?
A: Contaminated food or water.

Q: How is salmonellosis usually acquired?
A: From contaminated eggs or poultry.

Q: How does Salmonella cause disease?
A: Invades epithelial cells, multiplies, and may enter the bloodstream.

Q: How are salmonella infections treated?
A: Salmonellosis is self-limiting; typhoid fever requires antimicrobials.

Q: What causes bacterial food poisoning?
A: Staphylococcus aureus.

Q: What makes S. aureus food poisoning unique?
A: Toxin is ingested and acts fast (within 4 hours); food may taste normal.

Q: What are symptoms of food poisoning?
A: Nausea, vomiting, diarrhea, and cramps.

Q: What causes mumps?
A: Mumps virus.

Q: What are key symptoms of mumps?
A: Painful swelling of the salivary glands (especially parotid gland).

Q: Is there a treatment for mumps?
A: No specific treatment; vaccine prevents it.

Q: What causes viral gastroenteritis?
A: Caliciviruses, astroviruses, and rotaviruses.

Q: What virus is the leading cause of infant death from diarrhea worldwide?
A: Rotavirus.

Q: How is viral gastroenteritis treated and prevented?
A: Treated with fluid/electrolyte replacement; rotavirus vaccine exists.

Q: What causes viral hepatitis?
A: Hepatitis A, B, C, D, and E viruses.

Q: What are symptoms of hepatitis?
A: Jaundice, fatigue, abdominal pain, vomiting, and appetite loss.

Q: What causes liver damage in hepatitis?
A: The host immune response.

Q: How is hepatitis diagnosed and treated?
A: Diagnosed via jaundice, liver enlargement, serological tests; treated supportively.

Q: Which hepatitis viruses have vaccines?
A: HAV and HBV.

Q: Which group is most likely to develop chronic hepatitis B?
A: Newborns.

Q: What increases severity of hepatitis infections?
A: Co-infection with HBV and HDV.