Table 1.
Chlortetracycline-resistant anaerobic bacterial populations in fecal samples from organically raised and feral swinea
| Swine origin | Total anaerobe population levels at chlortetracycline concn (μg/ml)b: |
||
|---|---|---|---|
| 0 | 64 | 256 | |
| Organically raised | 5.9 × 1010 (A) | 9.5 × 109 (16%) (B) | 1.4 × 108 (0.24%) (C) |
| Feral | 1.1 × 109 (A) | 3.2 × 106 (0.3%) (B) | <2.6 × 104 (<.003%) (C) |
Values in the table are the average viable population levels (expressed as CFU/g [wet weight] of feces) of bacteria cultured anaerobically on RTC agar medium (spread plate method) and containing different concentrations of chlortetracycline.
Anaerobe populations on RTC medium without chlortetracycline for 10 organically raised swine ranged from to 2.9 × 1010 to 9.1 × 1010 CFU/g (SEM = 7.4 × 109) and for 19 feral swine ranged from 2.5 × 108 to 3 × 109 CFU/g (SEM = 1.8 × 108). Values in parentheses represent chlortetracycline-resistant CFU as percentages of total CFU for each animal group. Values with similar uppercase letters in parentheses (A, B, and C) were significantly different (P < 0.001, CI = 95%, Welch's t test).