TABLE 3.

Growth of ExPEC 408 and its derivatives in various media as determined using viable counts

Strain	Growth rate ina:
	LB broth (pH 7.0)	LB broth (pH 5.0)	LB broth + 400 μM 2,2′-dipyridyl	90% Chicken serum	75% Human serum	90% Human serum	Human urine
APEC O1	0.76	0.51	0.29	0.78	0.04	0.10	NDb
APEC O2	ND	ND	ND	ND	ND	ND	0.69
DH5α	0.44	0.33	0.00	0.31	−1	−1	0.16
ExPEC 408	0.76	0.56	0.20c	0.75	−0.15c	−0.09c	0.66
408.1	0.75	0.57	0.18c	0.77	−0.30d	−0.22d	0.59
408.2	0.76	0.58	0.21c	0.74	−0.13c	−0.12c	0.63

^aThe growth rate was determined by calculating the slope of log-transformed data during exponential growth. Negative values reflect a decline in survival as determined using viable counts.

^bND, not determined.

^cSignificantly different (P < 0.05) than the value for the known positive control (APEC O1 or APEC O2) as determined using a two-tailed Student t test.

^dSignificantly different (P < 0.05) than the value for the known positive control and ExPEC wild-type strain 408 as determined using a two-tailed Student t test.