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Questions and Answers
What is the primary cause of the severe diarrhea characteristic of cholera?
What is the primary cause of the severe diarrhea characteristic of cholera?
Which environment is most likely to harbor the cholera-causing bacterium, Vibrio cholerae?
Which environment is most likely to harbor the cholera-causing bacterium, Vibrio cholerae?
What is a common clinical manifestation of severe cholera?
What is a common clinical manifestation of severe cholera?
What can increase the risk of cholera transmission?
What can increase the risk of cholera transmission?
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What characteristic feature is associated with the stools of cholera patients?
What characteristic feature is associated with the stools of cholera patients?
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Which groups of people are at higher risk of exposure to cholera?
Which groups of people are at higher risk of exposure to cholera?
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What is the incubation period for cholera after infection?
What is the incubation period for cholera after infection?
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What is a key factor that contributes to the severity of cholera symptoms?
What is a key factor that contributes to the severity of cholera symptoms?
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What characteristic appearance do the stools of a cholera patient typically have?
What characteristic appearance do the stools of a cholera patient typically have?
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Which of the following substances is NOT significantly lost during cholera diarrhea?
Which of the following substances is NOT significantly lost during cholera diarrhea?
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What is the mainstay treatment approach for cholera?
What is the mainstay treatment approach for cholera?
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What visual symptom might suggest severe dehydration in a cholera patient?
What visual symptom might suggest severe dehydration in a cholera patient?
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Which biochemical test helps in identifying V. cholerae?
Which biochemical test helps in identifying V. cholerae?
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What type of agar is most effective for culturing V. cholerae?
What type of agar is most effective for culturing V. cholerae?
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Why are antibiotics considered for cholera treatment?
Why are antibiotics considered for cholera treatment?
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Which of the following is NOT a characteristic of cholera diagnosis?
Which of the following is NOT a characteristic of cholera diagnosis?
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What is a characteristic feature of Vibrio cholerae?
What is a characteristic feature of Vibrio cholerae?
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Which species is known to commonly cause diarrhea globally?
Which species is known to commonly cause diarrhea globally?
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What is the main structure responsible for the motility of Vibrio species?
What is the main structure responsible for the motility of Vibrio species?
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How does Vibrio cholerae adapt to its environment?
How does Vibrio cholerae adapt to its environment?
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Which of the following serotypes is primarily responsible for cholera?
Which of the following serotypes is primarily responsible for cholera?
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What type of media is used for the transport of Vibrio species without multiplication?
What type of media is used for the transport of Vibrio species without multiplication?
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Which component of Cholera toxin facilitates binding to host cells?
Which component of Cholera toxin facilitates binding to host cells?
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What happens to the ions and water due to the action of Cholera toxin?
What happens to the ions and water due to the action of Cholera toxin?
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What is a common clinical manifestation of Campylobacter infection?
What is a common clinical manifestation of Campylobacter infection?
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What method is used to confirm the diagnosis of Campylobacter infection?
What method is used to confirm the diagnosis of Campylobacter infection?
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Which antibiotic may be used to shorten the course of Campylobacter infection in severe cases?
Which antibiotic may be used to shorten the course of Campylobacter infection in severe cases?
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What is a characteristic feature of Helicobacter bacteria?
What is a characteristic feature of Helicobacter bacteria?
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What morphological characteristic differentiates Campylobacter from Helicobacter bacteria?
What morphological characteristic differentiates Campylobacter from Helicobacter bacteria?
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Why is treatment typically not necessary for Campylobacter infections?
Why is treatment typically not necessary for Campylobacter infections?
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How long does the incubation period typically last for Campylobacter infections?
How long does the incubation period typically last for Campylobacter infections?
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What percentage of the world's population is estimated to have Helicobacter pylori in their upper gastrointestinal tract?
What percentage of the world's population is estimated to have Helicobacter pylori in their upper gastrointestinal tract?
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What is the primary risk associated with chronic infections caused by this pathogen?
What is the primary risk associated with chronic infections caused by this pathogen?
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How does Helicobacter pylori primarily adhere to the gastric mucosa?
How does Helicobacter pylori primarily adhere to the gastric mucosa?
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What is the most common diagnostic test for detecting Helicobacter pylori antigens?
What is the most common diagnostic test for detecting Helicobacter pylori antigens?
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Which clinical manifestation is most common among individuals infected with this pathogen?
Which clinical manifestation is most common among individuals infected with this pathogen?
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Which sequence correctly represents the progression of complications stemming from chronic infection?
Which sequence correctly represents the progression of complications stemming from chronic infection?
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What is the role of urease produced by Helicobacter pylori?
What is the role of urease produced by Helicobacter pylori?
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What factor most likely leads to the development of duodenal ulcers in infected individuals?
What factor most likely leads to the development of duodenal ulcers in infected individuals?
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What is a characteristic of the Rapid Urease Test?
What is a characteristic of the Rapid Urease Test?
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What is the primary reason for antibiotic prophylaxis in disease prevention?
What is the primary reason for antibiotic prophylaxis in disease prevention?
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Which cholera vaccine is NOT mentioned as approved for use?
Which cholera vaccine is NOT mentioned as approved for use?
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Which method is primarily used to grow Campylobacter species?
Which method is primarily used to grow Campylobacter species?
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What characteristic is NOT true about Campylobacter jejuni?
What characteristic is NOT true about Campylobacter jejuni?
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Which body systems are primary reservoirs for Campylobacter species?
Which body systems are primary reservoirs for Campylobacter species?
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What is the function of the A subunit in cytolethal distending toxin (CDT)?
What is the function of the A subunit in cytolethal distending toxin (CDT)?
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How is Campylobacter typically transmitted to humans?
How is Campylobacter typically transmitted to humans?
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Which of the following elements is NOT part of the oral rehydration solution recommended by the World Health Organization?
Which of the following elements is NOT part of the oral rehydration solution recommended by the World Health Organization?
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Study Notes
Vibrio, Campylobacter, and Helicobacter
- Vibrio are a group of curved Gram-negative rods
- Vibrio cholerae causes cholera, a water-loss diarrhea
- Campylobacter jejuni is a common cause of diarrhea globally
- Helicobacter pylori causes peptic ulcers and other gastric issues
Vibrio Species
- Gram-negative curved rods, comma or S-shaped
- Motile with a single polar flagellum
- Can grow in aerobic or anaerobic conditions
- Commonly found in saltwater
- Different species cause different diseases (wound infections, gastroenteritis, bacteremia)
- Specific species are associated with particular sources of infection (e.g., V. cholerae with water/food, V. vulnificus with shellfish)
Vibrio Species Associated with Human Diseases
| Species | Source of Infection | Clinical Diseases |
|---|---|---|
| V. alginolyticus | Seawater | Wound infection, external otitis |
| V. cholerae | Water, food | Gastroenteritis |
| V. cincinnatiensis* | Unknown | Bacteremia, meningitis |
| V. fluvialis* | Seafood | Gastroenteritis, wound infection, bacteremia |
| V. furnissii* | Seawater | Gastroenteritis |
| V. harveyi* | Seawater | Wound infection (shark bite), bacteremia |
| V. etschnikovii* | Unknown | Bacteremia |
| V. mimicus* | Fresh water | Gastroenteritis, wound infection, bacteremia |
| V. parahaemolyticus | Shellfish, seawater | Gastroenteritis, wound infection, bacteremia, cellulitis |
| V. vulnificus | Shellfish, seawater | Bacteremia, wound infection, cellulitis |
Bacteriology of Vibrio Cholerae
- Produces Cholera toxin, a polypeptide with A1, A2 and 5 binding units.
- Causes active secretion of Na+, Cl–, K+, HCO3– and H2O from intestinal cells, causing diarrhea.
- Over 200 serotypes based on the lipopolysaccharide O antigen.
- Serotypes O1 and O139 cause cholera.
- Has low tolerance to acid but grows in alkaline conditions.
- O139 serotypes produce a polysaccharide capsule.
- Biofilms aid in attachment.
Bacteriological Media
- Transport media (keeps bacteria viable for weeks without multiplication) = Bile peptone transport medium and Cary blair medium.
- Enrichment media = Alkaline peptone water and Thiosulphate citrate bile sucrose agar medium (TCBS)
- Vibrio cholerae colonies appear on TCBS agar as yellowish colonies; colonies become greenish over time. Vibrio parahaemolyticus form yellow colonies
Epidemiology of Cholera
- Transmitted through contaminated water/food from an infected person.
- Requires inadequate water treatment, poor sanitation and hygiene.
- Brackish and marine waters are the natural environment for Vibrio cholerae.
- Shellfish can be a source if the bacteria is eaten raw or undercooked.
- Cholera is endemic in India and Africa.
Pathogenesis of Vibrio Cholerae
- Ingestion of large numbers (10^6 to 10^11)
- Incubation period is a few hours to 5 days
- Bacteria reach small intestine and swim to epithelial surface
- Adhere to cells by pili
- Release cholera toxin
- Cause massive fluid and electrolyte loss in small intestine
- Loss of electrolytes and high secretion leading to metabolic acidosis, shock, and death if untreated.
- Fluid and electrolytes loss results, hence stools are rice-water-like containing mucus, and high numbers of vibrios and epithelial cells.
Clinical Manifestations of Cholera
- Infection can be mild with no symptoms to severe.
- Severe disease causes watery diarrhea, vomiting, leg cramps.
- Rapid onset diarrhea with abdominal fullness
- Stools are watery, rice-water appearance, odorless, mucus flecks (quickly become watery).
- Disease lasts 4-5 days
Diagnosis of Cholera
- Stool specimen or rectal swab for bacteriological diagnosis
- Microscopic examination = Gram-negative comma-shaped bacilli
- Culture on TCBS or alkaline bile salt agar
- Biochemical tests (sugar fermentation, catalase, oxidase, motility)
- Latex agglutination (detects antigens in the stool)
Treatment of Cholera
- Oral rehydration is most effective
- Intravenous replacement fluids if severe dehydration
- Antibiotics (doxycycline, erythromycin, tetracycline) can shorten duration and reduce severity if needed.
Prevention of Cholera
- Proper sanitation and hygiene
- Safe food and water practices; cooking thoroughly, eating only peeled and cooked food, avoid using contaminated water.
- Antibiotics (doxycycline, erythromycin, tetracycline)
- Vaccines (oral cholera vaccines available.
Campylobacter
- Motile, oxidase-positive, Gram-negative curved rods (often S-shaped)
- Common cause of bacterial diarrhea globally
- Primarily found in animals (cattle, chickens)
- Undercooked poultry and unpasteurized milk are major sources
- Incubating period is 2-7 days
- Causes lower abdominal pain, fever, diarrhea containing blood and pus
- Self-limiting, lasts 3-5 days
Helicobacter Pylori
- Gram-negative bacteria, curved rods with polar flagella
- Thrives in the acidic stomach due to urease production
- Common cause of peptic ulcers and gastric cancer
- Transmitted via fecal-oral route (contaminated water, food)
Helicobacter Pylori Pathogenesis
- Adheres to gastric mucosa
- Motility helps reach less acidic areas
- Urease breaks down urea to ammonia, neutralizes gastric acid
- Leads to gastritis, ulcers, and potentially cancer.
Clinical Manifestations of Helicobacter Pylori Infection
- 85% asymptomatic
- Nausea, abdominal pain, vomiting, and diarrhea (lasting up to 2 weeks)
- Inflammation of pyloric antrum = duodenal ulcers
- Inflammation of stomach body = gastric ulcers
Diagnosis of Helicobacter Pylori
- Non-invasive = Serologic tests (detect antibodies), Urea breath tests (measure labeled CO2), Stool antigen tests (detect antigens)
- Invasive = Endoscopy (visual examination), Rapid Urease Test, Histology.
Treatment of Helicobacter Pylori
- Triple therapy (PPI + clarithromycin + amoxicillin/metronidazole)
- Other antibiotics (levofloxacin, tetracycline)
- Bismuth subsalicylate
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Description
This quiz explores the characteristics and diseases associated with Vibrio, Campylobacter, and Helicobacter species. Learn about their morphology, modes of transmission, and clinical significance. Dive into the details of how these bacteria can cause various gastrointestinal and other infections.
