LAB - Enterobacteriaceae

• IMVC REACTIONS are test done to our enterobacteriae to help them differentiate from one another
• M


  Methyl Red
• V

  Voges-Proskauer test
• Indole test

  1. Used for demonstrate the ability of certain bacteria to decomposed amino acid tryptophan to indole

  2. Positive it should have the formation of pink to red color at the top

  3. Negative it has no color change
• Methyl Red


  1. Determines whether the organisms perform mix acid fermentation and produces stable acid and products

  2. Methyl red positive, the medium should change red

  3. Methyl red negative, the medium has no color change and remain yellow
• Voges-Proskauer test

  1. Use to determine if an organism produces acetylmethyl carbinol from glucose fermentation

  2. Positive color is red

  3. Negative is yellow
• Citrate


  1. Used to test an organism ability to utilize citrate as a source of energy

  2. Positive it will change from green to intense blue

  3. Negative no growth and no color change and it will remain color green
• V means instead of negative and positive certain strain of an actual bacteria species have the enzyme system whereas other strains of the same species block certain enzyme of the system
• ESCHERICHIA

  • E. coli
• KLEBSIELLA

  • K. pneumoniae
  • K. oxytoca
  • K. ozaenae
• ENTEROBACTER

  • E. aerogenes
  • E. cloacae
  • E. agglomerans
• SERRATIA

  • S. marcescens
  • S. liquifaciens
• CITROBACTER

  • C. freundii
  • C. diversus/koseri
• HAFNIA

  • H. alvei
• PROTEUS

  • P. mirabilis
  • P. vulgaris
  • P. penneri
• PROVIDENCIA

  • P. rettgeri
  • P. stuartii
• MORGANNELA

  • M. morganni subsp. morganii
• SALMONELLA


  • Most serotypes
• SHIGELLA


  • ABC
  • D
• YERSINIA

  • Y. enterocolitica
  • Y. frediriksenii
  • P. penneri
• EDWARDSIELLA


  • E. tarda
• No special consideration required for ENTEROBACTERIACEAE SPECIMAN COLLECTION
• Transport media: Cary-Blair, Amies or Stuart Media
• Direct microscopic examination reveals Gram (-) bacilli
• Stool sample: not helpful but may reveal if GI infection is ("toxin mediated") ("invasive process")
• Culture

  1. 35C to 37C for 18-24 hours of incubation

  2. 1-5C ("Serratia & Yersinia)

  3. 45C to 50C ("E.coli")
• CULTURE: LACTOSE FERMENTERS

  • Escherichia coli
  • Klebsiella
  • Enterobacteria spp.
  • Citrobacter spp.
  • Serratia spp.
  • Salmonella spp.
  • Shigella spp.
  • Edwardsiella spp.
  • Hafnia spp.
  • Yersinia spp.
• BIOCHEMICAL TEST