TABLE 3.

Pathogenicities of ExPEC strains of different clinical origins for SPF chickens following intra-air sac inoculation^a

E. coli strain	Phylogenetic subcluster	Clinical originb	Serotype	% of chickens with contamination in:				Lesion score/8 (SD)	Death (%)
				Air sacs	Blood	Pericardial fluid	Liver
SP15	B2-1	Hu M	O18:K1	100	100	100	100	7.0 (0.6)	41.6
BEN3031	B2-1	Hu M	O18:K1	100	100	100	100	5.8 (1.2)	0
BEN3033	B2-1	Hu M	O18:K1	100	100	100	91.7	5.1 (0.8)	33.3
SP3	B2-1	Hu M	O18:K1	75	50	58.3	75	3.6 (3.1)	33.3
IHE3034	B2-1	Hu M	O18:K1	50	33.3	33.3	16.7	2.6 (1.8)	0
RS218	B2-1	Hu M	O18:K1	11.1	5.5	5.5	5.5	1.6 (1.2)	0
BEN79	B2-1	Av C	O18:K1	91.7	83.3	83.3	100	4.9 (0.8)	25
BEN374	B2-1	Av C	O18:K1	100	100	100	100	7.1 (0.9)	30
IHE3072	B2-1	Hu M	O2:K1	100	100	100	100	6.2 (1.0)	25
BEN2908	B2-1	Av C	O2:K1	100	100	100	100	5.0 (1.6)	37.5
BEN3009	B2-2	Hu Sc	O2:K1	25	0	0	0	1.5 (1.2)	0
BEN3012	B2-4	Hu Sd	O2:K1	100	58.3	100	100	4.8 (0.8)	0
EC79e	A	Av healthy	O2	6	0	0	0	0.5	0

^aGroups of 12 chickens were inoculated in the air sacs with bacterial cultures of E. coli strains. Bacterial colonization of internal organs, fibrinous lesions, and deaths were recorded.

^bStrains were from newborn meningitis (n = 7), human septicemia (n = 2), and avian colibacillosis (n = 3). Hu, human origin; Av, avian origin; M, newborn meningitis; S, septicemia; C, avian colibacillosis.

^cIsolated from an adult with a urinary tract infection.

^dIsolated from a newborn with septicemia.

^eNonpathogenic E. coli strain of avian origin used as a negative control (14).