Table 3.
Resistance genes identified in MH isolated from study animals.
| TxGroup (Isolates) | Isolates with ARGs (Multiple ARGs) | Amin (a3”, a6) | B-lac (bO, bR) | MLS (me, mm) | Phen | Tet (tH, tR) | Total ARGs |
|---|---|---|---|---|---|---|---|
| META (139 total) | 102 (75) | 43 (1, 42) | 77 (73, 34) | 73 (73, 73) | 41 | 100 (100, 51) | 491 |
| Arrival (39) | 13 (8) | 5 (0, 5) | 9 (6, 9) | 6 (6, 6) | 4 | 12 (12, 4) | 52 |
| WK3 (77) | 75 (55*) | 29 (0, 29) | 55 (55, 23) | 55 (55, 55) | 29 | 75 (75, 35) | 360 |
| WK10 (23) | 14 (12) | 9 (1, 8) | 13 (12, 3) | 12 (12, 12) | 8 | 13 (13, 10) | 79 |
| NO META (108 total) | 59 (26) | 17 (0, 17) | 28 (25, 25) | 26 (25, 26) | 17 | 47 (47, 13) | 196 |
| Arrival (33) | 11 (9) | 7 (0, 7) | 10 (9, 9) | 9 (9, 9) | 7 | 10 (10, 4) | 65 |
| WK3 (62) | 31 (13) | 7 (0, 7) | 14 (12, 13) | 13 (12, 13) | 7 | 30 (30, 6) | 100 |
| WK10 (13) | 7 (4) | 3 (0, 3) | 4 (4, 3) | 4 (4, 4) | 3 | 7 (7, 3) | 31 |
| Grand total (246) | 151 (101) | 60 (1, 59) | 105 (98, 59) | 99 (98, 99) | 58 | 147 (147, 62) | 687 |
*Significant difference in isolation of MDR MH compared to previous time point (McNemar’s χ2 test, p < 0.0001). TxGroup, treatment group; META, tulathromycin metaphylaxis; NO META, no tulathromycin metaphylaxis; ARG, antimicrobial resistance gene; WK3, week 3; WK10, week 10; Amin, aminoglycoside; B-lac, beta-lactams; MLS, macrolide-lincosamide-streptogramins; Phen, phenicols; Tet, tetracyclines; a3”,aph(3″); a6’, aph(6′); bo, blaOXA; bR, blaROB; me, erm(42); mm, msr(E); tH, tetH;tR, tetR.