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Table 3 Target populations and agar composition for bacterial ennumeration

From: Method comparison for the direct enumeration of bacterial species using a chemostat model of the human colon

Gut model growth medium

Solid components (g/L):

Peptone water (2.0), yeast extract (2.0), NaCl (0.1), K2HPO4 (0.04), KH2PO4 (0.04), MgSO4.7H2O (0.01), CaCl2.2H2O (0.01), NaHCO3 (2.0), haemin (0.005), cysteine HCl (0.5), bile salts (0.5), glucose (0.4), arabinogalactan (1.0), pectin (2.0), starch (3.0)

Liquid components:

vitamin K1 at 10 mL/L, and Tween 80 at 0.2%

Medium is sterilised at 121 °C for 30 min and cooled to 50 °C. Post-autoclaving glucose (0.4 g/L), and resazurin anaerobic indicator (0.005 g/L) are added.

Target populations

Agar

Supplements

Incubation (temp, environment)

Total anaerobes and total Clostridium spp.

Fastidious anaerobe agar

5% horse blood

37 °C, anerobic

Bifidobacterium spp.

42.5 g/L Columbia agar, and 5 g/L agar technical

0.5 g/L cysteine HCl, 5 g/L glucose

37 °C, anerobic

Bacteroides spp.

Bacteroides bile aesculin agar

5 mg/L haemin, 10 μL/L vitamin K, 7.5 mg/L vancomycin, 1 mg/L penicillin, 75 mg/L kanamycin and 10 mg/L colistin

37 °C, anerobic

Lactobacillus spp.

52.2 g/L MRS broth and 20 g/L agar technical

0.5 g/L cysteine hydrocloride, 20 mg/L vancomycin

37 °C, anerobic

Total facultative anaerobes

Nutrient agar

N/A

37 °C, aerobic

Lactose fermenting Enterobacteriaceae

MaConkey’s agar

N/A

37 °C, aerobic

Enterococcus spp.

Kanamycin aesculin azide agar

10 mg/L nalidixic acid, 10 mg/L aztreonam, and 20 mg/L kanamycin

37 °C, aerobic

Total spores (following alcohol shock for 1 h)

Fastidious anaerobe agar

5% horse blood

37 °C, anerobic

C. difficile total viable cells

Braziers CCEY agar

D-cycloserine (250 mg/L) cefoxitin (8 mg/L), 5 mg/L lysozyme, and 20 mL/L lysed horse blood

37 °C, anerobic

C. difficile spores

Braziers CCEY agar

5 mg/L lysozyme, and 2% lysed horse blood

37 °C, anerobic