LAB IS

• Somatic Ag (O Ag)

  Derived from the German Ohne Hauch, refers to the cell body alone excluding the flagella and capsule
• Nonflagellated nonmotile strains


  • Smooth & sharply defined colony structures with no hazy boundaries
• O Ag


  A complex mixture of discrete complete & incomplete antigenic components with a variety of specificities
• O Ag


  • Important in classification of enteric Gram (-) bacilli into major groups
• Enteric bacteria possessing O Ag without flagellar "H" Ag

  • Klebsiella pneumoniae
  • Shigella spp.
• O Ag


  • Relatively stable toward heat, alcohol or acids
• Preparation of O Ag

  Heating or treating the cells with alcohol or acids to destroy all flagellar Ag & leave only the O
• O Agglutination


  Fine granular precipitate which results from the reaction between nonflagellated cells and anti-O serum
• Flagellar "H" Antigen


  • Derived from Hauch
  • Relatively labile toward heat, alcohol, and acids
  • More specific than O Ag
  • Of more value in separating bacteria into specific strains or types
  • Also a composite of many different discrete antigenic entities
  • Of particular importance to the immunology of the enteric Gram (-) bacilli
• Preparation of Flagellar "H" Antigen


  Add equal volume of formol to an 18 to 24 hr broth culture
• H Agglutination


  Loose, coarse, flocculent precipitate
• Capsular Ag (K or Vi Ag)


  • Occur most bacteria but a play predominant role in only a few: Streptococcus pneumoniae and Bacillus anthracis
• Salmonella typhi


  A type of bacteria
• Cultures of Salmonella typhi inoculated on TSA

  1. Inoculation bottle

  2. 1 mL of the organism
• TSA (Tryptic Soy Agar)


  Non-selective nutrient agar
• BaSO4 no. 4 standard solution


  1.2 billion org/ml - maximum efficiency of the Ag
• Preparation of attenuated antigen

  1. 8mL 0.6% formalinized saline

  2. Kills the org. but doesn't affect the antigenicity of organism
• Scraping off the growth on the surface of the agar

  Glass beads
• Enriched medium for sterility testing

  1. 10 mL thioglycollate broth

  2. 1 drop of Antigen
• Incubation


  37 C for 24 hours
• Destroy the H antigen without killing the O antigen

  Absolute Alcohol
• Incubation


  Room temperature for 48 hours
• Preparation of O antigen

  Water Bath - 60 C for 60 minutes

  
  

  Centrifugation - 1,500 rpm for 2 minutes
• Bacillus subtilis is a common contaminant