Table 2. Overview of putative transmission clusters of Escherichia coli isolates from France, Germany, the Netherlands, Norway, Spain, the United Kingdom, 2013–2020 (n = 3,745).

Cluster	Phylogroup	ST	Sampling strategy		Source	Country	Plasmid	Average genome coverage (%)	SNP distance
			Monitoring	Longitudinal					Mean	Median	Range
44a	A	46	1	56	Cattle	DE, NL	ND	89.50	16	15	1–39
23b	A	2040	29	5	Poultry, poultry meat	NO, UK	IncI (n = 3)	86.80	32	30	2–91
449a	G	117	17	0	Poultry, poultry meat	NL, UK	IncI (n = 6)	93.30	43	46	1–73
193b	B2	429	7	6	Human, poultry, poultry meat	FR, NL, NO, UK	ND	86.80	28	20	4–88
174a	A	46	1	11	Cattle	DE, NL	ND	86.40	22	22	2–43
419a	A	2325	2	9	Cattle	DE, NL	ND	89.50	22	16	8–41
51a	A	744	2	9	Cattle, pig, poultry	ES, NL, UK	ND	92.40	32	29	1–68
580	B2	1193	2	7	Human	ES, FR, NO, UK	ND	86.50	78	80	50–114
509	B2	404	1	8	Human	ES, FR, NO, UK	ND	80.30	86	87	63–101
64	C	410	6	0	Pig, pork	ES, UK	IncI (n = 3)	87.30	82	88	25–122
764a	D	69	2	5	Human, pig, poultry	ES, FR, UK	ND	87.20	74	75	50–94
1185b	B1	683	6	0	Cattle, pig	DE, NL, UK	ND	90.50	22	24	7–28
1123	B2	131	1	4	Human	ES, NO, UK	ND	88.00	67	66.5	53–80
346	B1	58	3	2	Human, pig, poultry, poultry meat	NO, UK	ND	90.80	56	59.5	10–69
417a	F	1722	2	3	Cattle, human	DE, NL, NO	ND	93.60	54	49.5	17–89

DE: Germany; ES: Spain; FR: France; ND: not detected; NL: the Netherlands; NO: Norway; PCT: putative transmission cluster; SNP: single nucleotide polymorphism; ST: sequence type; UK: the United Kingdom.

^a PCTs which were deduced as vertical transmission events from core genome SNP distances; for ST1722 only cattle isolates were inferred.

^b PCTs which were associated with more than one vertical transmission event.