Transcript Lecture 21-Vibrio cholerae

‫بسم اهلل الرحمن الرحيم‬
FAMILY:
VIBRIONACEAE
Prof. Khalifa Sifaw Ghenghesh
3 Important Genera:
• Vibrio
• Aeromonas,
• Plesiomonas
• Oxidase +ve
Habitat:
‫بسم اهلل الرحمن الرحيم‬
Vibrio cholerae
I. V. cholera O1:
• Agglutinate in Antisera Directed
Against O1 Antigen.
• Produce Enterotoxin.
2. Non-Toxigenic V. cholera O1:
3. Non O1 V. cholera (NCV, NAV):
II. V. cholerae O139
Vibrio cholerae
Gram-negative, curved rods
Vibrio cholerae
Leifson flagella stain
Vibrio cholerae
curved rods with polar flagellum (EM)
V. cholerae O1
---------------------------------------------------
Biotye
Haemolysis (SRBC)
VP
El-tor
+
Classic
--
+
--
Resistance to PB
+
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
VIRULENCE FACTORS:
• Enterotoxin: CT
• Adherence: Ability to Attach to the
Microvilli at the Brush Borders of the
Epithelial Cells.
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EPIDEMIOLOGY:
• Causes Widespread Disease.
• Human Carriers:
• Modern International Travel:

PATHOGENESIS & CLINICAL
INFECTION:
•
•
•
•
•
Infectious Dose:
Incubation period:
Abrupt Onset of Diarrhoea & Vomiting
Stool > Watery (Rice Water), Odorless
Fatality Rate:

LAB. DIAGNOSIS:
• Isolation & Identification of the
Organism.
• Media: TCBS
• Transport Media:
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TREATMENT:
• Prompt Replacement of Fluid &
Elecrolytes
• Tetracycline and others

PREVENTION & CONTROL:
• Adequate Sewage Treatment and
Water Purification Systems.
• Vaccination: ??
Typical Vibrio cholera
contaminated water supply
Vibrio parahaemolyticus
• Halophilic vibrio
• Associated with seafood
• Gastroenteritis:
– Outbreaks of Food Poisoning
• Extraintestinal infections > wounds
• Virulence Factors:
– Haemolysin >
– heat-stable cytotoxin
– Heat-labile enterotoxin
– Adherence to human intestinal cells
Aeromonas species
A. hydrophila, A. sobria & A. caviae
• Enterotoxins, Cytotoxins, Haemolysins,
Etc…
• Gastroenteritis, Septicaemia, and Skin
& Wound Infections

TREATMENT
• TMP-SMX, Tetracycline, Gentamicin
• Resistant to b-Lactam Antibiotics.