Media used in the anaerobic bacteriology can be freshly prepared or purchased from commercial suppliers. Media for anaerobic culture prepared in the laboratory should be used within 2 weeks of preparation as long storage degrades the quality of the media due to peroxide accumulation and dehydration. Anaerobic culture media contains reducing agents such as cysteine.
Pre-reduced, anaerobically sterilized media are produced by different commercial suppliers, which have extended shelf life of up to six months. The primary plating media for inoculating anaerobic specimen includes a non-selective blood agar and one or all of the following mentioned selective media.
Nonselective media used in anaerobic bacteriology:
- Cooked meat broth (e.g. Robertson’s Cooked Meat Medium): Non-selective for the cultivation of anaerobic organisms; with the addition of glucose, can be used for gas-liquid chromatography.
- Anaerobic blood agar: It is a non-selective medium for the isolation of anaerobes and facultative anaerobes.
- Egg-yolk agar (EYA): Non-selective for determination of lecithinase and lipase production by Clostridia and Fusobacteria.
- Peptone-yeast extract glucose broth (PYG): Non-selective for the cultivation of anaerobic bacteria for gas-liquid chromatography.
Selective and differential media used in anaerobic bacteriology:
- Bacterioides bile esculin agar (BBE): It is selective and differential for Bacteriodes fragilis group and good for presumptive identification.
- Laked Kanamycin-vancomycin blood agar (LKV): It is selective for isolation of Prevotella and Bacteriodes spp.
- Anaerobic phenylethyl alcohol agar (PEA): Selective for inhibition of gram-negative rods and swarming by some Clostridia.
- Cycloserine cefoxitin fructose agar (CCFA): selective for Clostridium difficile.
- Thioglycollate broth: Nonselective for the cultivation of anaerobes; as well as facultative anaerobes and aerobes.