II. Gastrointestinal Infections

Sanitation

Key for preventing most gastrointestinal infections.

Microflora

Large and diverse populations in the GI tract that compete with pathogens.

Lysozyme

An enzyme found in saliva that helps break down bacterial cell walls.

Lactoferrin

A protein in saliva that has antimicrobial properties.

Low pH of the stomach

Helps to kill pathogens ingested with food.

Mucus layer

Protective layer present throughout the entire GI tract.

Gut-associated lymphoid tissue

Provides immune function in the gastrointestinal tract.

Exotoxin

A toxin secreted by bacteria that can destroy cells or disrupt metabolism.

Enterotoxin

A type of exotoxin that specifically targets the intestine.

Endotoxin

A toxic substance that is part of the bacterial cell wall and released upon cell rupture.

Gastric ulcers

Ulcers in the stomach caused by Helicobacter pylori.

Helicobacter pylori

A gram-negative bacterium associated with gastric ulcers and stomach cancer.

Robin Warren and Barry Marshall

Discovered Helicobacter pylori and won the Nobel Prize in 2005.

Urease

An enzyme that helps Helicobacter pylori neutralize stomach acid.

Fecal-oral transmission

Mode of transmission for Helicobacter pylori and many other pathogens.

Cholera

An infection caused by Vibrio cholerae leading to severe diarrhea and dehydration.

Cholera toxin

An enterotoxin produced by Vibrio cholerae that causes fluid loss in the intestine.

John Snow

Conducted an early epidemiological study to trace cholera outbreaks.

Gastroenteritis

An inflammation of the stomach and intestines often caused by pathogens.

Enterohemorrhagic E. coli O157:H7

A pathogenic strain of E. coli that causes severe diarrhea and potentially kidney failure.

Traveler’s diarrhea

Diarrhea caused by Enterotoxigenic E. coli, especially in travelers.

Salmonellosis

Illness caused by Salmonella bacteria affecting the GI tract.

Typhoid fever

A severe infection caused by S. typhi that can enter all body cells.

Campylobacter jejuni

A common cause of bacterial diarrhea in the U.S. associated with poultry.

Clostridium difficile

A bacterium that can cause antibiotic-associated diarrhea and severe inflammation.

Viral gastroenteritis

Diarrhea caused by viruses like Rotavirus or Norwalk virus.

Rotavirus

A virus that causes severe gastrointestinal illness in children.

Norwalk virus

A virus responsible for many food poisoning outbreaks, especially on cruise ships.

Porcine Epidemic Diarrhea Virus (PEDV)

A coronavirus affecting pigs that leads to high mortality rates in piglets.

Food Poisoning

Caused by pre-formed toxins, resulting in vomiting and diarrhea.

Staphylococcus aureus

A bacterium that produces heat-stable toxins responsible for food poisoning.

Rehydration therapy

Important treatment for dehydration caused by diarrheal diseases.

Antibiotic resistance

A significant problem consisting of bacteria becoming resistant to antibiotic treatment.

Lyses

The rupture or disintegration of bacterial cells releasing endotoxins.

Zoonosis

A disease that can be transmitted from animals to humans.

Cramps

Abdominal pain often associated with gastrointestinal infections.

Contaminated water supplies

Common source of outbreaks for diseases like cholera.

Poor sanitation

A contributing factor for the spread of waterborne diseases.

H. pylori infection

An infection linked to gastric ulcers and sometimes stomach cancer.

Healthcare-associated infections

Infections that occur in healthcare settings, such as those caused by Clostridium difficile.

Heat-stable toxin

A type of toxin produced by some bacteria, such as Staphylococcus aureus, that can endure cooking temperatures.

Gut microbiome

The community of microorganisms living in the intestinal tract, contributing to digestion and immunity.

Infectious dose

The amount of pathogen needed to cause infection.

Bacterial cell wall

The rigid outer structure of bacteria, contributing to their shape and protection.

Cholera outbreak

A significant rise in cases of cholera often linked to contaminated water.

Epidemiological study

Research analyzing the distribution and determinants of health-related states.