Comparison of clinical and immunological findings in gnotobiotic piglets infected with Escherichia coli O104:H4 outbreak strain and EHEC O157:H7

Table 1 Infective dose administered, bacteriological and clinical findings in individual animals

Group animal number	Infective dose (CFUs)	CFUs/g stool day 4 p.i.	CFUs/g stool day 5–6 p.i.	OD Stx ELISA day 5–6 p.i.	CFUs/g stool day 9–12 p.i.	OD Stx ELISA day 9–12 p.i.	Average clinical score (animal/group)	Clinical signs, assessed at least once	Day of death
Negative
1	Mock	Sterile	Sterile	n.a.	Sterile	0.009 (N)	0.00	None	10
2	Mock	Sterile	Sterile	0.025 (N)	Sterile	0.012 (N)	0.11	Reduced appetite	9
3	Mock	Sterile	Sterile	0.020 (N)			0.00	None	6^a
							Ø 0.04
E. coli O104:H4
4	1.00 × 10⁹	1.22 × 10¹⁰	2.81 × 10¹⁰	n.a.	8.60 × 10⁸	4.538 (P)	0.53	Reduced appetite, dehydration	10
5	1.00 × 10⁹	8.17 × 10⁹	6.88 × 10¹⁰	n.a.	2.62 × 10⁹	3.993 (P)	0.51	Reduced appetite, dehydration, mild central nerval signs	10
6	2.19 × 10⁸	2.13 × 10¹⁰	3.38 × 10⁷	n.a.	Sterile	2.746 (P)	0.46	Reduced appetite, dehydration	10
7	2.19 × 10⁸	1.18 × 10⁷	2.10 × 10⁹	n.a.	Sterile	3.492 (P)	0.52	Reduced appetite, mild central nerval signs	9
8	2.19 × 10⁸	3.13 × 10⁹	1.63 × 10⁹	4.122 (P)			0.07	Reduced appetite	6^a
9	2.19 × 10⁸	5.58 × 10⁹	1.11 × 10¹⁰	2.833 (P)	4.65 × 10⁷	4.561 (P)	0.11	Reduced appetite, dehydration	12
							Ø 0.37
E. coli O157:H7
10	2.20 × 10⁸	5.43 × 10⁹		.			0.74	Severe neurological signs	4^b
11	2.20 × 10⁸	1.02 × 10¹⁰	8.35 × 10⁹	n.a.	5.95 × 10⁹	4.599 (P)	0.67	Mild central nerval signs, dehydration	11
12	2.08 × 10⁸	1.95 × 10⁷	2.50 × 10⁷	4.358 (P)			0.30	Severe neurological signs	5^b
13	2.08 × 10⁸	1.30 × 10⁹	1.37 × 10⁸	4.527 (P)			0.50	Dehydration	5^b
							Ø 0.55

Interpretation Shiga toxin ELISA: optical density (OD) < 0.070 = negative; OD > 0.070/<0.100 = indefinite, ODs > 0.100 = positive
n.a. not assessed, N negative, P positive
^aEuthanized early due to organisational reasons
^bEuthanized early due to severe clinical symptoms

ISSN: 1757-4749