TABLE 3.
Percentages of root-nodulating isolates resistant to a mixture of the three antibiotics (sulfamethazine, tylosin, and chlortetracycline) each supplemented into the culture medium at a concentration of 10 mg · liter−1
| Soil antibiotic treatment (mg · kg−1) | % of resistant isolatesa |
|||
|---|---|---|---|---|
| Mean | SE | Lower limit (95%) | Upper limit (95%) | |
| Control (0) | 54.0 | 9.8 | 31.3 | 76.7 |
| Low dose (0.1) | 61.0 | 9.8 | 38.3 | 83.7 |
| Intermediate dose (1) | 37.3 | 9.8 | 14.6 | 60.0 |
| High dose (10) | 50.3 | 9.8 | 27.6 | 73.1 |
a
The isolates were obtained from plants grown in soils that received the indicated concentrations of antibiotics in the field. An ANOVA indicated the differences were not significant (P = 0.434).