. 2019 Jan 24;38(4):801–809. doi: 10.1007/s10096-019-03475-5

Table 2.

Microbiological characteristics of cases categorised with high-virulent (number of cases; N = 475) versus low-virulent (N = 652) Shiga toxin-producing Escherichia coli (STEC) infections, notified to the Norwegian Surveillance System for Communicable Diseases (MSIS), Norway, 2007–2017 (N = 1127)

Characteristics	Category	All cases^a (N = 1127)		High-virulent STEC cases^a (N = 475)		Low-virulent STEC cases^a (N = 652)		Chi-square p value^b
Characteristics	Category	N	%	N	%	N	%	Chi-square p value^b
Serogroup distribution	O157	195	20	192	43	3	1	< 0.001
	O103	136	14	16	4	120	23
	O26	126	13	78	17	48	9
	O145	96	10	67	15	29	5
	Other	418	43	96	21	322	62
eae ^c	Positive	710	67	406	87	304	51	< 0.001
eae ^c	Negative	352	33	60	13	292	49	< 0.001
ehxA ^d	Identified	700	62	365	77	335	51	< 0.001
ehxA ^d	Not identified	427	38	110	23	317	49	< 0.001

^aThe numbers and proportions reported per column for each characteristic use the number of cases with available (known) information regarding each characteristic

^bA p value of ≤ 0.05 (italicised) was considered statistically significant

^cIntimin-encoding gene (Escherichia coli attaching and effacing)

^dEnterohaemolysin-encoding gene (enterohaemolysin)