TABLE 3.
Distribution of determinants of antimicrobial resistance to tetracyclines, florfenicol, β-lactams, quinolones, and macrolides, alone or in combination, with corresponding sequence types, among 80 unique E. coli strains isolated from 22 calves
| AMR determinanta combinations | n | Sequence types |
|---|---|---|
| Tet(A) | 10 | 10 (n = 4), 58, 120, 329, 1302, 10850, and 13058 |
| Tet(B) | 10 | 56, 58 (n = 3), 101, 718, 2522 (n = 2), 3695, and 155 |
| Tet(B) + GyrA_S83L | 1 | 2522 |
| TEM-1 | 1 | 723 |
| TEM-1 + Tet(A) | 13 | 10, 58, 69 (n = 4), 101, 162, 410, 446, 6126, 10850, and 13059 |
| TEM-1 + Tet(B) | 1 | 69 |
| TEM-1 + Tet(A) + Mph(B) | 1 | 10 |
| TEM-1 + Tet(A) + Tet(B) + Mph(B) | 3 | 58 (n = 3) |
| TEM-1 + Tet(A) + FloR | 6 | 3057, 8580 (n = 2), and 58 (n = 3) |
| TEM-1 + Tet(A) + Tet(B) + FloR | 1 | 2522 |
| TEM-35 + Tet(B) + FloR | 1 | 949 |
| TEM-1 + Tet(A) + FloR + GyrA_S83L | 2 | 301 (n = 2) |
| TEM-1 + Tet(A) + FloR + GyrA_S83L + Mph(B) | 1 | 57 |
| TEM-1 + Tet(C) + FloR + GyrA_S83L | 1 | 301 |
| TEM-1 + Tet(A) + FloR + GyrA_D87Y | 1 | 783 |
| TEM-1 + Tet(A) + GyrA_D87Y | 1 | 117 |
| TEM-1 + Tet(A) + Tet(M) + GyrA_S83L | 1 | 58 |
| TEM-1 + Tet(B) + GyrA_D87N + GyrA_S83L + ParC_S80I | 1 | 162 |
| TEM-1 + Tet(A) + Tet(M) +FloR + GyrA_D87N + GyrA_S83L + ParC_S80I | 1 | 361 |
| OXA-1 +TEM-1 +Tet(B) +FloR + Mph(B) +GyrA_D87N + GyrA_S83L + ParC_S80I | 1 | 162 |
Antibiotic resistance determinants and their function: GyrA_D87N and GyrA_D87Y, DNA gyrase subunit A with substitution of aspartic acid (D) to asparagine (N) or to tyrosine (Y) at codon 87 for quinolone resistance; GyrA_S83L, DNA gyrase subunit A with substitution of serine (S) to leucine (L) at codon 83 for quinolone resistance; ParC_S80I, DNA topoisomerase 4 subunit A with substitution of serine (S) to isoleucine (I) at codon 80 for quinolone resistance; Tet(A), Tet(B), and Tet(C), tetracycline efflux; Tet(M), ribosomal protection for tetracycline resistance; OXA-1, TEM-1, and TEM-35, β-lactamase; FloR, phenicol efflux; and Mph(B), macrolide phosphotransferase.