Vibrio, Campylobacter, Helio Flashcards
Gram negative, curved rod, facultative anaerobe, single flagellum
Vibrio cholera
What is a serogroup?
Bacteria of the same species with different antigenic determinants on the cell surface
What is a biotype?
(biovar)
Different strains of the same bacterial species
distinguished by a group of phenotypic or genetic traits
How many serogroups of V.cholera cause epidemic disease?
2
How many chromosomes does V.cholera have?
2 circular chromosomes
Which chromosome of V.cholera contains pathogenicity islands?
Answer: Chromosome II
Chromosome I - larger and contains genes for cell function and housekeeping.
Chromosome II is smaller and carries integron island (genes with antibiotic resistance)
What is Cholera Toxin?
CT is a proteinaceous enterotoxin secreted by
V. Cholera
-responsible for the severe diarrhea characteristic of the disease.
Describe the pathogenicity of Cholera Toxin
Short Answer: Absorption of cholera toxin causes diarrhea via increase in cyclic AMP
Long Answer: absorption of CT–>adenylate cyclase–>formation of cAMP–>secretion of chloride and bicarbonate–>secretion of large amount of water in lumen
How is cholera diagnosed?
Rice water stool
How is cholera treated?
Replace fluids/electrolytes
The following are characteristics common to the superfamily for which two species?
- Gram negative
- Helical (spiral or curved)
- Pleomorphic
- Microaerophilic (curve when exposed to air)
- Neither ferment nor oxidize carbohydrates
campylobacter and heliobacter
Most common cause of acute infectious diarrhea in developed countries
campylobacter (jejuni)
Gull-winged appearance
campylobacter
- small, thin, helical (spiral or curved)
- gram negative
- tendency to become coccoid and elongated *upon exposure to air or prolonged culture
- gull-winged
campylobacter
What is a capnophile?
An organism that prefers an CO2 environment
- Distinctive rapid “darting motility”
- Long sheathed polar flagellum
- microaerophilic & capnophilic
- thermophile
- often nonculturable
campylobacter
A secondary autoimmune disease resulting from campylobacter jejuni infection. Causes acute inflammatory demyelinating neuropathy in response to cross-reaction to O-antigens.
Answer: Guillain-Barre Syndrome
associated with C. jejuni serogroup O19
How do humans acquire Campylobacteriosis?
- Ingestion of contaminated food (particularly poultry), unpasteurized milk, or improperly treated water
- Foods that neutralize gastric acidity, e.g., milk. *Fecal-oral transmission
Which Campylobacter has an S-layer protein “microcapsule” ?
Answer: C. fetus
Causes zoonotic abortion
Cellular virulence factors for Campylobacter?
Endotoxin
Flagellum: Motility
Adhesins: Mediate attachment to mucosa
Invasins
GBS is associated with C. jejuni serogroup O19
S-layer protein “microcapsule” in C. fetus:
Extracellular virulence factors for Campylobacter?
Enterotoxins
Cytopathic toxins
Describe gastroenteritic pathogenesis of Campylobacter jejuni
Damage to the mucosal surfaces of the jejunum, ileum, colon
Inflammatory process due to invasion into the intestinal tissue
Describe Lab Identification of Campylobacter jejuni using microscopy
Gull-wing appearance in gram stain
Darting motility in fresh stool
Name 3 important pathogens of the Helicobacter species
Helicobacter pylori (human; no animal reservoir)
H. cinaedi (male homosexuals; rodents)
H. fenneliae (male homosexuals; rodents)
