Heliobacter pylori and Vibrio cholera

Helicobacter pylori Characteristics

• Curved, gram-negative rod

• Colonizes gastric mucosa

• Acid-resistant

Transmission of H. pylori

Person-to-person or consuming contaminated food/water (oral-oral or fecal-oral)

H. pylori Virulence Factors

• Urease neutralizes acid

• Flagella and shape for motility

• Adherence

• VacA and CagA exotoxins

Diseases by H. pylori

• Gastritis

• Peptic Ulcer Disease

• Stomach Cancer

Peptic Ulcer Disease

Sores of stomach, SI, esophagus

Stomach Cancer

Untreated acid irritation/gastric mucosa erosion; result of chronic infection

Peptic Ulcer Symptoms

• Pain/discomfort

• Bloating/burping

• Full after little food

• No appetite, N/V

• Dark stools from blood (fatigue/low RBC)

How H. pylori forms ulcers

1. Invasion of mucus and attachment to epithelium

2. Secrete exotoxins causing inflammation, thinning of mucus

3. Gastric acid destroys epithelium and tissue

Diagnosis of H. pylori

Urea Breath Test; endoscopy/biopsy; definitive diagnosis requires culture or NAAT

Treatment of H. pylori

Antibiotic therapy early on, Proton Pump Inhibitors (acid blocker)

Prevention of H. pylori

• Complete antibiotic/PPI therapy

• Hand-washing/food handling

• Lifestyle change

How does diet increase risk of H. pylori?

Stress, spice, caffeine, NSAIDs increase chance for infection, slow healing, worsen pain

Vibrio cholerae Characteristics

• Highly motile, single flagella

• Comma-shaped gram-negative

What disease does V. cholerae cause?

Cholera, acute diarrheal disease caused by contaminated water

Transmission of V. cholerae

• Brackish/coastal waters free-living

• Drinking contaminated water (fecal-oral)

Endemic Cholera

Regularly occurring in coastal communities from high tides, hot and dry seasons

Epidemic Cholera

Spread by water, high precipitation, poor water treatment

Life Cycle of Cholera

1. Ingestion of contamination water → Colonize SI

2. Use of flagellum to propel to epithelium

3. Produce toxin coregulated pilus and cholera toxin

4. TCP helps colonize, CT binds receptors

5. CT → High cAMP, efflux of water/electrolytes

6. Form biofilms, repression of virulence factors

7. Migrate to lumen, upregulate aquatic genes

8. Excreted from host into environment

V. cholerae Virulence Factors

• Biofilm allows survival in acid

• Cholera Toxin - increases ion concentration to increase water secretion and diarrhea (AB exotoxin)

• Toxin-coeregulated Pilus - colonization of mucosa

Symptoms of Cholera

• Acute, profuse diarrhea

• “Rice-water stools”

• Rapid, large water loss and dehydration

Diagnosis of Cholera

Symptoms and fecal culture

Treatment of cholera

• Oral rehydration solution

• Antibiotics shorten and diminish severity

Prevention of Cholera

• Sewage treatment/water management

• Vaxchora vaccine for travel