2. Medias & Stains

Types of agar, Gram stain, special stains pg. 140-142

Routine Medias and their Purpose

• Blood Agar (BA, BAP) - Most bacteria; determines hemolytic reactions

• Chocolate Agar - Haemophilus and Neisseria sp.; enriched with Hemoglobin or IsoVitalleX

• Phenylethyl Alcohol Agar (PEA) - Selects for gram pos cocci and anaerobic gram neg bacilli

• Columbia Colistin-Nalidixic Acid (CNA) - Selects for gram pos cocci

• Thayer-Martin Agar - N. gonorrhoeae and N. meningitidis

• CAMPY-Blood Agar - Campylobacter sp.

• Thioglycolate Broth - “Back-up” for Anaerobes

• Lowenstein-Jensen Agar, Middlebrook 7H10 Agar, and Petragnani Agar - Mycobacterium sp.

Anaerobic Media and their Purpose

• Bacteroides Bile Esculin Agar (BBE) - Selects for B. fragilis Group (Black Colonies)

• Kanamycin-Vancomycin Laked Blood (KVLB) - Bacteroides sp. (Enhances Pigment Production

• Cycloserine-Cefoxitin Fructose Agar (CCFA) - C. difficile

• CDC Anaerobic Blood Agar - Anaerobes (enriched with Hemin, Cystine, and Vitamin K)

• Cooked or Chopped Meat Medium - Anaerobes

Special Media and their Purpose

• Bordet-Gengou Agar - B. pertussis

• Buffered Charcoal Yeast Extract (BYCE) - Legionella sp.

• Cystine-Glucose Agar - F. tularensis

• Fletcher’s Medium - Leptospira

• Skirrow Agar - Helicobacter pylori

• Thiosulfate Citrate-Bile Salts (TCBS) - Vibrio sp.

• Vaginalis Agar (V-Agar) (human blood) - Gardnerella vaginalis

• Cystine-Tellurite Blood (Tinsdale) - C. diphtheriae (Black Colonies)

• Loeffler’s Medium - C. diphtheriae (Enhances Grouping and Metachromatic Granules)

Select Biochemical Reactions