Table 4.
Comparison of tetracycline and sulfonamide resistance gene prevalence in organic farms and native prairies in Nebraska.
| Gene | Mechanism | Conventional manure prevalence (%) | Organic farm soil (n = 98) | Prairie soil (n = 100) | P-value |
|---|---|---|---|---|---|
| Sul1 | Enzyme | 100A,B | 16 | 91 | <0.0001 |
| tet(A) | Efflux | 8C | 2 | 52 | <0.0001 |
| tet(B) | Efflux | 0–4B,C | 2 | 27 | <0.0001 |
| tet(C) | Efflux | 0–100%B,C,D | 0 | 14 | 0.0001 |
| tet(D) | Efflux | No data | 29 | 55 | 0.0004 |
| tet(E) | Efflux | 28B | 14 | 15 | 0.887 |
| tet(G) | Efflux | No data | 56 | 15 | <0.0001 |
| tet(K) | Efflux | No data | 0 | 9 | 0.0024 |
| tet(L) | Efflux | No data | 13 | 34 | 0.0006 |
| tet(M) | Ribosomal | 80–100%B,D | 11 | 15 | 0.4316 |
| tet(O) | Ribosomal | 85–100%B,D | 8 | 37 | <0.0001 |
| tetA(P) | Ribosomal | No data | 30 | 17 | 0.359 |
| tet(Q) | Ribosomal | 80–100%B,D | 48 | 0 | <0.0001 |
| tet(S) | Ribosomal | 49B | 45 | 12 | <0.0001 |
| tet(X) | Enzymatic | No data | 33 | 2 | <0.0001 |
| Mean # ARGs∗∗ | 3.07 | 3.94 | |||
P-value is for comparison of gene % positive in organic vs prairie soils. Manure prevalence % values are calculated from data from peer-reviewed publications that measured gene prevalence from various manure-impacted substrates. AData from Martietal. (2014). BData from Storteboometal. (2010). CData from Sengeløvetal. (2003). DData from Jindaletal. (2006). **Based on n = 15 assayed for this study.