list of culture media

• Acetate agar

  • Use: Differential medium [E.coli from Shigella spp.]
  • Principle & Components:
  • Acetate: carbon source
  • Amm. salt: nitrogen source
  • Bromthymol blue: green to blue
  • Results:
  • (+) growth: Escherichia spp. & Enterobacteriaceae
  • (-) growth: Shigella, Proteus, and Providencia spp.
• Alkaline peptone water

  • Use: Enrichment medium for Vibrio and Aeromonas spp. (required)
  • Principle & Components:
  • Alkaline pH: Uninhibited replication of organisms while temporarily suppressing the replication of others
  • Uses: provide fatty acids
• American Trudeau Society Medium (ATSM)

  • Use: Enriched medium used for the isolation of M. tuberculosis
  • Principle & Components:
  • Potatoes: provide a carbon source
  • Malachite green: inhibitory for normal bacterial flora
  • Results: Dark brown or black colonies
• Bacteroides Bile Esculin Agar (BBEA)

  • Use: Selective differential agar to isolate and identify group D streptococci and enterococci
  • Principle & Components:
  • Bile: separates bile-resistant species from bile-sensitive ones (no growth)
  • 1% esculin: ability (+) or inability (-) to hydrolyze esculin
  • Oxgall: inhibits the growth of most gram-positive organisms
  • Esculin: ability (+) or inability (-) to hydrolyze esculin
  • Esculin/oxgall: detect vancomycin-resistant streptococci & enterococci
• Bismuth Sulfite Agar

  • Use: Selective medium for the isolation of Salmonella spp.
  • Principle & Components:
  • Inhibit gram (+) organisms
  • Brilliant green & bismuth: gram inhibits gram (+) bacteria enriching Salmonella normal flora
  • Results: S. gallinarum, choleraesuis & paratyphi (light green)
• Blood Agar, Anaerobic, CDC

  • Use: Standard medium for the isolation of fastidious anaerobes
  • Principle & Components: Hemin and base, yeast extract, L-cysteine, hemin, sheep blood and vitamin K1
• Blood Agar, Anaerobic, Brucella Basic, Wadsworth, Etc.

  • Use: Useful enrichment medium for the isolation of moderately fastidious, obligate anaerobes
  • Principle & Components: Sheep's blood: enrichment; vitamin K1 and hemin
• Blood Agar, Anaerobic, with Kanamycin and Vancomycin (KV)

  • Use: Selective enrichment medium for the isolation of species of Bacteroides spp. and Prevotella melanogenica
• Blood Agar, Anaerobic, Laked, with Kanamycin, Vancomycin, and Vitamin K (KVL)

  • Use: Primary isolation of obligate gram-negative anaerobes, particularly Bacteroides spp.
  • Principle & Components: Kanamycin & vancomycin: inhibit all cocci & facultative gram (-) bacilli, except the pseudomonads
• Blood Agar, Rabbit

  • Use: Enrichment medium in recovery and the demonstration of β-hemolysis by Haemophilus spp. and Gardnerella vaginalis
• Blood Agar, Sheep

  • Use: Routine medium to cultivate moderately fastidious organisms
  • Principle & Components: Infusion agar or tryptic soy agar base + 5% to 10% defibrinated sheep, rabbit, or human blood; yeast extract, hemin, vitamin K, and defibrinated sheep blood enrichment
• Phenylethyl Alcohol Agar, Anaerobic, CDC (PEA)

  • Use: Selective enrichment medium for isolation of Bacteroides, Prevotella, and other obligate anaerobes from specimens containing a mixture of obligate and facultative anaerobes
  • Principle & Components: Infusion agar or tryptic soy agar base + 5% to 10% defibrinated sheep, rabbit, or human blood; yeast extract, hemin, vitamin K, and defribinated sheep blood; enrichment; phenylethyl alcohol: inhibits facultative gram (-) anaerobes by suppressing DNA synthesis and cell division