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

Functions of the digestive system

Digests food, absorbs nutrients and water, eliminates waste.

GI tract

The pathway from mouth to anus.

Accessory digestive organs

Help with mechanical digestion or secrete digestive fluids.

Viridans streptococci

Microbiota found on the tongue and teeth.

Esophagus, stomach, and duodenum

These are mostly microbe-free due to peristalsis and fast food movement.

Most microbial-rich part of the digestive tract

The lower small intestine and colon.

Causes of dental caries

Streptococcus mutans.

Virulence factors involved in tooth decay

Dextran and pili help form biofilms on teeth.

Causes of periodontal disease

Porphyromonas gingivalis, which uses proteases to break down gums.

Cavity treatment and prevention

Treat by filling; prevent with good oral hygiene.

Causes of peptic ulcers

Helicobacter pylori.

Virulence factors of H. pylori

Flagella (motility), adhesins, urease (neutralizes acid), toxins (damage cells).

Transmission of H. pylori

Fecal-oral route.

Diagnosis and treatment of ulcers

Diagnosed by x-ray and clinical tests; treated with antimicrobials and acid blockers.

Bacterial gastroenteritis

Inflammation of stomach or intestines caused by bacteria.

Common symptoms of bacterial gastroenteritis

Nausea, vomiting, diarrhea, cramps, and abdominal pain.

Dysentery

Severe diarrhea with blood and mucus.

Causes of cholera

Vibrio cholerae.

Cholera toxin

Causes cells to secrete electrolytes and water, leading to watery diarrhea.

Key sign of cholera

"Rice-water" stool.

Cholera treatment and prevention

Rehydration and tetracycline; prevent with hygiene and vaccines.

Causes of Campylobacter diarrhea

Campylobacter jejuni.

Virulence factors of C. jejuni

Adhesins, cytotoxins, and endotoxins.

Common food linked to C. jejuni

Poultry.

Causes of antimicrobial-associated diarrhea

Clostridioides (formerly Clostridium) difficile.

Dangerous features of C. difficile

It forms endospores and releases two toxins that cause inflammation and colitis.

Diagnosis and treatment of C. difficile

Toxin detection in stool; treated with antimicrobials and stopping unnecessary antibiotics.

Causes of salmonellosis and typhoid fever

Salmonella enterica.

Typhoid fever spread

Contaminated food or water.

Acquisition of salmonellosis

From contaminated eggs or poultry.

How Salmonella causes disease

Invades epithelial cells, multiplies, and may enter the bloodstream.

Treatment of salmonella infections

Salmonellosis is self-limiting; typhoid fever requires antimicrobials.

Causes of bacterial food poisoning

Staphylococcus aureus.

Unique feature of S. aureus food poisoning

Toxin is ingested and acts fast (within 4 hours); food may taste normal.

Symptoms of food poisoning

Nausea, vomiting, diarrhea, and cramps.

Causes of mumps

Mumps virus.

Key symptoms of mumps

Painful swelling of the salivary glands (especially parotid gland).

Treatment for mumps

No specific treatment; vaccine prevents it.

Causes of viral gastroenteritis

Caliciviruses, astroviruses, and rotaviruses.

Leading cause of infant death from diarrhea worldwide

Rotavirus.

Treatment and prevention of viral gastroenteritis

Treated with fluid/electrolyte replacement; rotavirus vaccine exists.

Causes of viral hepatitis

Hepatitis A, B, C, D, and E viruses.

Symptoms of hepatitis

Jaundice, fatigue, abdominal pain, vomiting, and appetite loss.

Cause of liver damage in hepatitis

The host immune response.

Diagnosis and treatment of hepatitis

Diagnosed via jaundice, liver enlargement, serological tests; treated supportively.

Hepatitis viruses with vaccines

HAV and HBV.

Group most likely to develop chronic hepatitis B

Newborns.

Severity increase of hepatitis infections

Co-infection with HBV and HDV.