VIBRIO
• Gram-negative
• Rigid short curved comma shaped rods with rounded or slightly pointed ends
• Highly motile-single polar flagella
• 1.5µ X 0.2 -0.4 µ in size
• Noncapsulated
• Strongly aerobic
• Non spore forming
Habitat
• Vibrios are present in marine environments and surface waters
Vibrio Classification
• 1. Cholera vibrios : Causes epidemic and pandemic cholera
• 2. Non-cholera vibrios: Cause ear, wound, soft tissue, and extra-intestinal
infections
Important species
• V. mimicus
• V. vulnificus
• V. hollisae
• V. fluvialis
• V. damsela
• V. furnissi
• V. alginolyticus
• V. metschnikovii
• V.cholera: Important member of the genus - gastroenteritis
• Vibrio parahaemolyticus: Causes gastroenteritis, and possibly extra-intestinal
infections
Cultural characteristics
• Strongly aerobic and facultative anaerobes
• Temperature: 16- 400C (opt- 370C )
• Growth is better in an alkaline medium
• pH - 6.4 – 9.6 (opt 8.2)
• Extremely sensitive to acidic pH which kills it
• Most are halotolerant and halophilic: NaCl stimulates their growth
• Vibrios grow on media containing 6% NaCl
• Grows well on ordinary media
, • Selective Medium –TCBS agar (Thiosulphate citrate bile sucrose)-produces
yellow colonies that are readily visible against the dark green background of
the agar
Biochemical reactions
• Ferments glucose, mannitol, maltose, mannose, and sucrose and produce acid,
but not gas
• Indole: +ve
• Nitrates are reduced to nitrites
• Catalase: +ve
• Oxidase: +ve (used for preliminary identification )
• Methyl red and urease tests: -ve
Resistance
• Susceptible to heat, drying and acids
• Resist high alkalinity
• Destroyed at 550C in 15 mins
• Survive in clean water for 30 days
• Survive at room temperature for 1-4 days and for a week in the refrigerator
• Susceptible to 2,4-diamino-6,7-diisopropylpteridine phosphate
VIBRIO-Mode of Transmission
• Person-to-person
• Transmission occurs primarily by drinking water or eating food that has been
contaminated by the feces of an infected person
• Through contaminated raw sea food
Cholera
• Cholera - infection of the small intestine
• Caused by Vibrio cholerae
• Source: Ingestion of contaminated water and food
• Short Incubation period: 1-5 days
• Despite being an avoidable and treatable condition cholera affects 3–5 million
people worldwide and causes 100,000–130,000 deaths a year
• Most cases happen in under developed and developing countries
Pathogenesis
• V. cholerae is pathogenic only for humans and not for animals
• Very few organisms are adequate to cause infection
• Water (infectious dose = 104)
• Gram-negative
• Rigid short curved comma shaped rods with rounded or slightly pointed ends
• Highly motile-single polar flagella
• 1.5µ X 0.2 -0.4 µ in size
• Noncapsulated
• Strongly aerobic
• Non spore forming
Habitat
• Vibrios are present in marine environments and surface waters
Vibrio Classification
• 1. Cholera vibrios : Causes epidemic and pandemic cholera
• 2. Non-cholera vibrios: Cause ear, wound, soft tissue, and extra-intestinal
infections
Important species
• V. mimicus
• V. vulnificus
• V. hollisae
• V. fluvialis
• V. damsela
• V. furnissi
• V. alginolyticus
• V. metschnikovii
• V.cholera: Important member of the genus - gastroenteritis
• Vibrio parahaemolyticus: Causes gastroenteritis, and possibly extra-intestinal
infections
Cultural characteristics
• Strongly aerobic and facultative anaerobes
• Temperature: 16- 400C (opt- 370C )
• Growth is better in an alkaline medium
• pH - 6.4 – 9.6 (opt 8.2)
• Extremely sensitive to acidic pH which kills it
• Most are halotolerant and halophilic: NaCl stimulates their growth
• Vibrios grow on media containing 6% NaCl
• Grows well on ordinary media
, • Selective Medium –TCBS agar (Thiosulphate citrate bile sucrose)-produces
yellow colonies that are readily visible against the dark green background of
the agar
Biochemical reactions
• Ferments glucose, mannitol, maltose, mannose, and sucrose and produce acid,
but not gas
• Indole: +ve
• Nitrates are reduced to nitrites
• Catalase: +ve
• Oxidase: +ve (used for preliminary identification )
• Methyl red and urease tests: -ve
Resistance
• Susceptible to heat, drying and acids
• Resist high alkalinity
• Destroyed at 550C in 15 mins
• Survive in clean water for 30 days
• Survive at room temperature for 1-4 days and for a week in the refrigerator
• Susceptible to 2,4-diamino-6,7-diisopropylpteridine phosphate
VIBRIO-Mode of Transmission
• Person-to-person
• Transmission occurs primarily by drinking water or eating food that has been
contaminated by the feces of an infected person
• Through contaminated raw sea food
Cholera
• Cholera - infection of the small intestine
• Caused by Vibrio cholerae
• Source: Ingestion of contaminated water and food
• Short Incubation period: 1-5 days
• Despite being an avoidable and treatable condition cholera affects 3–5 million
people worldwide and causes 100,000–130,000 deaths a year
• Most cases happen in under developed and developing countries
Pathogenesis
• V. cholerae is pathogenic only for humans and not for animals
• Very few organisms are adequate to cause infection
• Water (infectious dose = 104)
