Table 5. Cow-level evaluation of the association of season and isolation of a Salmonella resistant to the referred antimicrobial from an individual fecal sample.
| Season2 | Ceftriaxone (6/239)1 | Ciprofloxacin (4/239)1 | Tetracycline (18/239)1 | Ampicillin (9/239)1 | MDR* (7/239)1 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| %3 | OR4 [95% CI] | P-value5 | %3 | OR4 [95% CI] | P-value5 | %3 | OR4 [95% CI] | P-value5 | %3 | OR4 [95% CI] | P-value5 | %3 | OR4 [95% CI] | P-value5 | |
| Winter | 4 | 1.7 [0.7–4.3] | 0.19 | 1 | 0.4 [0.07–2.6] | 0.35 | 12 | 1 [0.6–1.7] | 0.92 | 4 | 0.6 [0.2–1.3] | 0.2 | 4 | 1.3 [0.5–3.1] | 0.49 |
| Spring | 2 | 0.47 [0.1–1.9] | 0.28 | 5 | 7.7 [2.0–28.5] | 0.0003 | 8 | 0.5 [0.3–1.07] | 0.07 | 11 | 2.7 [1.4–5.4] | 0.0025 | 5 | 1.4 [0.5–3.4] | 0.48 |
| Summer | 6 | 3.2 [1.3–7.6] | 0.0052 | 0 | – | – | 13 | 1 [0.6–1.8] | 0.8 | 6 | 1.2 [0.6–2.5] | 0.59 | 6 | 2.3 [1.03–5.2) | 0.036 |
| Fall | 0 | – | – | 1 | 0.6 [0.1–3.0] | 0.58 | 15 | 1.3 [0.8–2.2] | 0.21 | 3 | 0.4 [0.1–1.04] | 0.056 | 0 | – | – |
Notes:
P-values in bold indicates a significant difference was observed.
Analysis was conducted using weighted Chi-square.
Number of isolates resistant to the referred drugs and the total number of samples tested.
Season for which odds of isolating a antimicrobial resistant Salmonella was evaluated.
Survey adjusted percent of fecal samples culture positive for a Salmonella resistant to the referred drugs within the population of animals for which samples were collected during the referred season.
Odds ratio for culturing a Salmonella resistant to the referred drug during the referred season compared to any of the other season.
P-value for the odds ratio.
Salmonella isolates identified as multidrug resistant.
During the referred season either no animals with a culture positive for a Salmonella resistant to the referred drugs was isolated, or no animals with a culture negative fecal sample for Salmonella or a culture positive sample for Salmonella that is susceptible to the referred antimicrobial drug. Therefore effect of season could not be evaluated.