Used to discriminate between closely related org. with differences in characteristic growth patterns and biochem. changes

pH indicators

• Acid Production
• H2S production
• Indole Production
• Coagulase Activity

• Combines aspects of both selecective and diff

• Selects for NaCl
• iF Staphyloccocus present, will grow

• Differential: contains phenol red as pH indicator
• Butt Reactions: glucose fermentation, H2S production
• Slant reaction:lactose and/or sucrose fermentation

• Gas: Bubble- positve, no bubble- neg
• H2S: black in butt: +, not black:-
• K= alkaline, A= acidic
  
  • Finish this card later

• Fe is indicator of H2S
• Kovac's must be added after incubation to observe indole production.
  
  • Amber= indole neg
  • Red= indole pos
• Semisolid medium=allows us to observe motility

• Selective: tellurite and LiCl
• Differential: tellurite and egg yolk
  • Coag +: clear zone
  • Coag -: no clearance
  • tellurite reduction: black

• Staph grows on these

• Selective: NaCl (if it grows, contains staph)
• Differential: pheno red as indicator
  • Neutral/Alkaline=red= mannitol -
  • Acidic= yellow=mannitol +

• Selective: crystal violet and tellurite
• Diff: trypan blue and tellurite
  • Strep= blue
  • Entero=dark blue/black

• Selective: methylene blue and eosin Y dyes
• Diff: methylene blue and eosin Y are pH indicators
  
  • n-a: opaque growth
  • acidic=purple/black
  • highly acidic= green/metallic sheen
• Acidic=lactose positive

Selective: crystal violet and bile salts

Differential: neutral red pH indicator

• n-a: opaque growth
• acidic=pink growth
• Acidic= lactose positive
• basic= lactose neg

• Selective: sodium citrate, bile salts, brilliant green
• diff: neutral red as pH indicator, Fe to indicate H2S
• N-a: opaque growth (lactose neg)
• Acidic- pink growth (lac positive)
• H2S=black