Prevalence and risk factors associated with nasal carriage of methicillin-resistant staphylococci in horses and their caregivers

Table 1 Details of the barns and horses studied

	Internal barn	Racehorse barns	Show riding barns	Pleasure riding barns	All external barns
Barns [n]	1	6	7	8	21
Barns where tacks are shared [n]	1	4	2	3	9
Total horses [n]	5	104	225	286	615
Horses per barn [n]	5	17 ± 9	32 ± 15	32 ± 14	27 ± 14
Total horses sampled [n]	5	33	38	39	110
Age [years]	16.0 ± 7.4	5.5 ± 3.6	13.0 ± 4.4*	13.6 ± 6.8*	11.1 ± 6.3
Sex [M: F]	2:3	17:14	25:13	23:16	65:43
Weight [kg]	476 ± 33	440 ± 52	516 ± 93*	478 ± 170	481 ± 123
Travelling rate ratio [IRR (95%CI)]	–	3.06 (1.13, 8.27)	1.48 (0.49, 4.51)	1.00	–
Hospitalizations last year [n]	0	1	4	0	5
Horses intended for food consumption [n]	1	3	0	7	10
Horse-specific antimicrobial treatment rate ratio [IRR (95% CI)]	–	3.16 (0.84, 11.84)	2.31 (0.63, 8.54)	1.00	–
Barn-estimated antimicrobial treatment rate ratio [IRR (95% CI)]	1.50	10.00 (4.16, 23.97)	2.00 (0.81, 4.97)	1.00	–

The data are expressed as absolute counts or means ± SD. Data from the internal barn were systemically excluded from the statistical analyses. “All external barns” includes data from the 21 racehorses and shows riding barns. Barn estimates of antimicrobial treatments administered are based on personnel interviews and cover all horses stabled at the barn during the 12 months preceding the interview. Horse-specific values are based on personnel interviews and cover antimicrobial treatments administered in the last 12 months only to the horses included in the study. IRR were compared with Poisson regression and robust variance estimates.
*Significantly different from racehorse barns (p < 0.05, Kruskal‒Wallis test).

ISSN: 1297-9716