LECTURE - Vibrio cholerae Flashcards
1
Q
V. cholerae characteristics
A
- gram neg curved rods
- motile with polar sheathed flagellum
- tolerant to higher NaCl
- cholera toxin
- major antigenic classes based on capsule and LPS structure
- causes life-threatening watery diarrhea that infects 3-5 million ppl a year; killing 100 000
2
Q
Agglutination test for major O antigen
A
- Non-O1
- O1 (A) or 139 = problem!!; biovars = classical and eltor
3
Q
Cholera the disease
A
- acquired through ingestion of water contaminated with feces
- voluminous diarrhea (up to 20L a dsay)
- dehydration
- collapse of circulatory system
- rice-water stool
- bind to microvilli of SI = produce toxins
- can kill a healthy person within 12-24 hours depending on dose; can kill most number of humans in shortest period of time
4
Q
V. cholerae treatment
A
oral rehydration and intravenous rehydration therapy (esp. if they are unconscious)
5
Q
Virulence factors of V. cholerae
A
- motility
- VPI PAthogenicity Island = Phi phage genes, Tcp pili and regulatory proteins
- Cholera toxin (CTX phage genes)
- “other toxins” = milder diarrhea
- antibiotic resistance
6
Q
Motility of cholera
A
- single polar flagellum, sheathed
- consists of 5 protein subunits (flaABCDE)
7
Q
V. cholerae PI
A
- VPI encodes for toxin co-regulated pili (Tcp pili)
- originated from genome of a filamentous phage
- form bundles at one end
- are a receptor for CTX phage that carries cholera toxin genes
8
Q
Tcp pili important for adhesion to
A
human enterocytes but dont do this on their own
9
Q
Cholera toxin
A
- A-B type; ADP-ribosylating
- responsible for most of pathogolgy of disease
- genes contained in an operon within a filamentous bacteriophage (CTX) that lysogenizes V. cholerae
10
Q
receptor for cholera toxin
A
Ganglioside GM1 (each B subunit recognizes this)
11
Q
“Other” cholera toxis
A
- Zot (Zonula occludans toxin)
- Ace (Accessory cholera enterotoxin)
both enterotoxins, part of CTX phage genome and play a role in bacteriophage replication
