Table 7.

Likelihood of identifying resistance among NTSEC isolates cultured from feces collected as composite pen floor samples or as individual samples collected per rectum on the same sampling days^1,2

Resistance outcome3	Type of fecal sample	OR4	95% CI5	P-value
Ampicillin	Individual	0.8	0.3 – 1.8	0.58
	Composite	Reference
Chloramphenicol	Individual	0.9	0.4 – 2.5	0.94
	Composite	Reference
Kanamycin	Individual	0.6	0.2 – 2.5	0.5
	Composite	Reference
Nalidixic Acid	Individual	3.5	0.3 – 44.8	0.41
	Composite	Reference
Streptomycin	Individual	1.3	0.8 – 2.2	0.31
	Composite	Reference
Sulfisoxazole	Individual	1.2	0.7 – 2.2	0.5
	Composite	Reference
Tetracycline	Individual	0.9	0.6 – 1.7	0.92
	Composite	Reference
Trimethoprim- Sulfamethoxazole	Individual	1.7	0.4 – 8.5	0.5
	Composite	Reference

¹n=412 isolates recovered from 137 fecal samples collected from individual cattle, and n=198 isolates recovered from 40 composite pen floor fecal samples.

²Susceptibility testing was performed using broth microdilution.

³Other drugs could not be analyzed because of low resistance prevalence (amikacin, amoxicillin-clavulanate, cefoxitin, ceftiofur, ceftriaxone, ciprofloxacin, gentamicin, and nalidixic acid).

⁴ Odds Ratio. Analyses controlled for potential lack of independence related to repeated measures and hierarchical data structure using generalized estimating equations.

⁵95% confidence intervals.