TABLE 2.
Comparison of predominant antimicrobial resistance phenotypes of Salmonella isolates from pigs (fecal, cecal, or mesenteric lymph node samples) and the environment (floor swab, truck swab, lagoon, or lairage swab samples)a
| Resistance pattern | No. of isolates | No. (%) positive on:
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Farm 1
|
Farm 2
|
Farm 3
|
Farm 4
|
All farms
|
|||||||
| Animal | Environment | Animal | Environment | Animal | Environment | Animal | Environment | Animal | Environment | ||
| ACSSuT | 812 | 151 (52) | 44 (26) | 266 (83) | 69 (39) | 56 (67) | 7 (50) | 202 (86) | 17 (20) | 675 (71) | 137 (30) |
| SSuT | 226 | 86 (30) | 45 (27) | 1 (0.3) | 57 (32) | 1 (1) | 1 (7) | 35 (40) | 88 (9) | 138 (30) | |
| Pansusceptible | 71 | 25 (9) | 25 (15) | 6 (2) | 7 (3) | 8 (9) | 38 (4) | 33 (7) | |||
| T | 59 | 2 (1) | 17 (10) | 2 (1) | 32 (18) | 4 (5) | 1 (0.4) | 1 (1) | 9 (1) | 50 (11) | |
| ACSSuTAxCfCroKGm | 44 | 7 (2) | 17 (5) | 5 (3) | 10 (4) | 5 (6) | 34 (4) | 10 (2) | |||
| ST | 34 | 4 (1.5) | 8 (5) | 3 (1) | 3 (2) | 12 (14) | 1 (7) | 3 (3) | 19 (2) | 15 (3) | |
| A(ST)AxCfCro | 18 | 9 (3) | 4 (2) | 5 (36) | 9 (1) | 9 (2) | |||||
| STK | 17 | 12 (7) | 5 (2) | 5 (0.5) | 12 (3) | ||||||
| SuT | 19 | 8 (3) | 7 (4) | 4 (5) | 8 (1) | 11 (2) | |||||
| CSSuT | 10 | 10 (12) | 10 (2) | ||||||||
| SSuTKGm | 9 | 6 (2) | 3 (1) | 9 (1) | |||||||
| ASSuTKGm | 11 | 8 (5) | 3 (1) | 3 (0.3) | 8 (2) | ||||||
| S | 7 | 5 (2) | 1 (0.6) | 1 (1) | 6 (0.6) | 1 (0.2) | |||||
| AT | 4 | 3 (4) | 1 (0.4) | 4 (0.4) | |||||||
| Others | 64 | 12 (4) | 7 (4) | 18 (6) | 8 (4.5) | 7 (8) | 8 (3) | 2 (2) | 45 (5) | 19 (4) | |
| Total | 1405 | 292 (21) | 167 (12) | 341 (24) | 185 (13) | 84 (6) | 14 (1) | 235 (17) | 87 (6) | 952 (68) | 453 (32) |
a
Statistically significant associations (P < 0.05) between sample origin (animal or environment) and predominant resistance patterns, including ACSSuT (odds ratio, 5.6), SSuT (odds ratio, 0.23), T (odds ratio, 0.08), and pansusceptible (odds ratio, 0.53), were found.