Table 1.

Toxin production in different culture media.

Culture Medium	Medium Components	pH	OD600	TcdB (ng/mL)
BHI	Brain Heart Infusion/yeast extract	7.0	0.79	588 (534–643) (n = 2)
TYfor	Tryptone/yeast extract	7.0	0.82	1046 (1039–1054) (n = 2)
TYbac	Tryptone/yeast extract	7.0	1.36	453 (409–496) (n = 2)
N-Z-Soy BL4	N-Z-Soy BL4/yeast extract	7.0	0.90	723 (578–869) (n = 2)
PY	Peptone/yeast extract	7.0	0.81	192 (191–192) (n = 2)

All cultures were incubated unagitated for 5 days at 37 °C, and their optical density at 600 nm (OD₆₀₀) was measured on day 5. ^for = tryptone (Formedium), ^bac = Bacto tryptone (BD Biosciences).