FIG. 2.

Growth of E. coli ATCC 25922 determined by monitoring viable counts in urine. The bacteria were first grown at pH 7 with different amounts of sodium nitrate (1 to 10 mM NaNO₃). After 20 h, the culture containing nitrite and bacteria was transferred (and thereby diluted 1/10) to slightly acidic urine (pH 5.5) containing ascorbic acid (10 mM), and bacterial growth was again monitored. Data are means ± standard deviations (n = 6).