Vibrio spp. Flashcards
What shape do Vibrio spp. bacteria have?
Curved-rod shaped
They are classified as gram-negative bacteria.
How are Vibrio spp. bacteria propelled?
By a single polar flagellum
This adaptation allows them to navigate effectively in aquatic environments.
Where are Vibrio spp. naturally found?
Freshwater estuarine and marine environments
They are especially prevalent in warmer climates and show seasonal distribution.
How many chromosomes do Vibrio spp. have?
Two chromosomes
This is unique as most bacteria typically only possess one chromosome.
What contributes to the adaptability of Vibrio spp.?
Their ability to undergo recombination and horizontal gene transfer
This contributes to the spread of virulence and antibiotic resistance genes.
What are O antigens used for in Vibrio spp.?
Serotyping and species identification
O antigens are part of the lipopolysaccharide structure in their outer membrane.
What is a primary reservoir of infection for Vibrio spp.?
Faecal contamination of water and food
Poor sanitation and lack of clean drinking water are closely linked to these infections.
What areas are at risk for Vibrio spp. infections?
Slums, camps for refugees
Disruption of water and sanitation systems increases the risk of transmission.
What is the causative agent of cholera?
Vibrio cholerae
It is the most clinically significant species among Vibrio spp.
What type of disease is cholera?
A severe, acute secretory diarrheal disease
It is caused by the cholera toxin produced by certain toxigenic strains.
What are the potential consequences of cholera if not treated promptly?
Hypovolemic shock and death
Extremely rapid fluid loss leads to dehydration and electrolyte imbalance.
How many cholera cases occur globally each year?
3 to 5 million cases
This results in around 100,000 deaths annually.
What percentage of cholera deaths occur in children under 5 years of age?
Around 50%
This highlights the vulnerability of young children to the disease.
Cholera can be classified as endemic, epidemic, or _______.
Pandemic
Cholera has been observed in several waves across centuries.
In how many countries is cholera endemic?
50 countries
Endemic refers to a disease or condition regularly found among particular people or in a certain area.
List the regions where cholera epidemics have occurred.
- Africa
- Asia
- Middle East
- South America
- Central America
- Caribbean
These regions have reported significant outbreaks of cholera.
What was the number of cholera cases reported during the 2010 Haiti epidemic?
800,000 cases
This epidemic also affected neighboring countries like the Dominican Republic, Cuba, and Mexico.
How many cholera cases were reported in Yemen in 2017?
330,000 cases
What type of toxin is the cholera toxin (CT)?
AB Toxin
The AB toxin consists of two components: an A (active) component and a B (binding) component.
What is the mechanism by which cholera toxin causes fluid loss?
cAMP-mediated activation of anion secretion
This leads to inhibition of NaCl absorption and massive secretion of Cl−.
What severe symptom is caused by cholera toxin?
Severe diarrhea
On what genetic element is cholera toxin encoded?
Filamentous phage
What is the role of the toxin-coregulated pilus (TCP)?
- Mediates adherence
- Microcolony formation
- Required for intestinal colonization
TCP is essential for the initial stages of infection by Vibrio cholerae.
What is TCP a receptor for?
CTXΦ
