vibro

• What are the main objectives of the lecture on Vibrio?

  To cover morphology, classification, virulence determinants, associated diseases, treatment, and prevention.
• What are the morphological characteristics of Vibrio?


  • Curved Gram-negative rods
  • Comma-shaped
  • Actively motile with a single polar flagella
• What is the optimal growth temperature for Vibrio?

  The optimal growth temperature for Vibrio is 37c
• What type of agar is used for culturing Vibrio?

  Thiosulphate-citrate-bile salt sucrose agar (TCBS).
• What is the pH range in which Vibrio can grow?

  Vibrio can grow in a pH range of 8.5 to 9.5.
• How long can Vibrio survive on fruits and vegetables when kept cool?

  Vibrio can survive for 4-7 days on fruits and vegetables when kept cool.
• What are the two main types of antigens in Vibrio classification?

  The two main types of antigens are flagella ('H' antigen) and somatic ('O' antigen).
• Which serogroups of Vibrio are known to cause epidemics and pandemics?

  Serogroups O1 and O139.
• What are the biotypes and serotypes of Vibrio O1?

  • Biotypes: El Tor and Classical
  • Serotypes:
  • Ogawa = A & B antigens
  • Inaba = A & C antigens
  • Hikojima = A, B & C antigens
• How do the El Tor and Classical biotypes of Vibrio differ in terms of haemolysin production?

  El Tor biotype produces haemolysin, while Classical biotype does not.
• What diseases are associated with medically important Vibrios?

  • V. cholerae: Epidemic and pandemic cholera
  • V. parahaemolyticus: Gastroenteritis
  • Other Vibrios: Ear, wound, soft tissue infections

  
• What are the adhesion factors of Vibrio that contribute to its pathogenicity?

  Mucinases dissolve the glycoprotein coating of small intestinal cells.
• What is the infective dose of V. cholerae when transmitted through water?

  The infective dose is $10^{10}$ or more V. cholerae.
• What is the incubation period for cholera infection?

  The incubation period is between 0.5 to 5 days.
• How does cholera toxin affect the intestinal cells?

  It increases intracellular cAMP, leading to hypersecretion of water and electrolytes.

  
• What are the clinical features of cholera?

  • Sudden onset of profuse diarrhea and vomiting
  • Dehydration symptoms: intense thirst, oliguria, muscle cramps
  • Watery 'rice water stool' with no fecal matter
• What is the mortality rate of untreated cholera?

  The mortality rate is 50-60% if untreated.
• What specimens are used for laboratory diagnosis of cholera?

  • Stool
  • Rectal swab
  • Vomitus
• What is the purpose of inoculating samples into alkaline peptone water during laboratory diagnosis?

  It enhances rapid growth of Vibrio.
• What is the appearance of colonies on TCBS agar for Vibrio?

  Colonies appear yellow on TCBS agar.
• What biochemical test is used to identify Vibrio biotypes?

  Oxidase test is used to identify Vibrio biotypes.
• What is the recommended treatment for cholera?

  Fluid and electrolyte replacement intravenously until diarrhea stops.

  
• How much fluid may a cholera patient need per day?

  A cholera patient may need 20-25 liters of fluid per day.
• What are the characteristics of cholera carriers?

  • Convalescent patients: 7-14 days
  • Few cases: 4-5 weeks
  • Chronic carriers: may carry for years
  • Casual carriers in endemic areas: $10^2 - 10^3\text{/gm of faeces}$
• What are the prevention and control measures for cholera?

  • Exclude infected patients from handling food
  • Killed oral cholera vaccines available
  • Vaccination required for travel to endemic areas

  
• What is the major source of cholera transmission?

  The major source is contaminated water used for bathing, swimming, drinking, and contaminated food.
• What are the epidemiological characteristics of cholera?

  • Disease of the poor due to poor sanitation
  • Strictly a human parasite
  • Aquatic resident in non-endemic areas
• What is the incubation period for V. parahaemolyticus gastroenteritis?

  The incubation period is 2-20 hours.
• What are the characteristics of V. parahaemolyticus?

  • Associated with food poisoning from raw fish and shellfish
  • Requires 6-8% NaCl in medium
  • Found in warm coastal waters

  
• What color do colonies of V. parahaemolyticus appear on TCBS agar?

  Colonies appear green on TCBS agar.
• What is the significance of the biblical references at the end of the study material?

  • They emphasize the importance of wisdom and spiritual insight.
  • They encourage receiving Christ for personal transformation.
• Endotoxin(enterotoxin)

  A subunit (A1 & A2) and a ring of 5 B subunits. Epithelial cell receptors in s. intestine
• What is the infective dose when vehicle for transmission is food?

  10 exponent 2 to 10 exponent 4
• Predisposing factors for vibro include

  hypoclorhydria, achlorhydrria and blood group O
• Pathogenesis

  Cholera attaches to epithelial cells, releasing toxins that bind to the GM1 receptor, allowing A Subunit entry and activation, which then increases intracellular cAMP, leading to water and electrolyte hypersecretion. Note that cholera does not invade tissues.