Table 1.

Results of logistic regression for univariate and multivariate models Only cases with full information on the analysed variable or set of variables were included.

Variable	Category	No.	Positive %	Univariate			Multivariate
				ORa	-95 % CI	+95% CI	ORa	-95 % CI	+95% CI
Region	East	65	39	Ref
	Northwest	72	51	1.7	0.9	3.3	2.6	1.2	5.8
	Southwest	153	59	2.3	1.3	4.1	3.8	1.9	7.9
Herd size	Small	83	30	Ref
	Medium	87	60	3.5	2.7	7.2	3.8	1.9	7.5
	Large	116	63	3.4	1.8	6.5	5.4	2.7	11
Production type	Farrow-to-finish	65	31	Ref
	Wean-to-finish	38	63	3.9	1.7	9.0	4.0	1.6	10
	Grow-to-finish	185	58	3.1	1.7	5.6	2.0	1.0	4.0
Purchase of pigs	No purchase	73	36	Ref
	Purchase from 1-2 sources	165	55	2.2	1.3	3.9
	Purchase from multiple sources	49	71	4.5	2.1	9.9
Animal flow system	Continuous	90	40	Ref
	AI/AOb with cleanup	22	46	1.3	0.5	3.2
	AI/AObwith cleanup and disinfection	154	59	2.2	1.3	3.4
Flooring	Concrete with bedding	25	16	Ref
	Partially slatted	41	44	7.1	2.4	21
	Totally slatted	219	58	4.1	1.2	14
Cattle in the farm	Present	235	56	Ref
	Absent	55	36	0.5	0.2	0.8
Use of antimicrobialsc	No	126	42	Ref
	Yes	164	60	2.1	1.3	3.4

Categories with the lowest MRSA prevalence were chosen as references (indicated as Ref).

^a p-value < 0.05

^b All in/all out

^c Reported treatments at group level