TABLE 2.
VSH-1-mediated transduction of chloramphenicol and tylosin resistances between B. hyodysenteriae strains A203 and B78
| VSH-1 virion | No. of transductants/108 CFUa
|
|
|---|---|---|
| Tylosin resistant (10 μg/ml) | Chloramphenicol resistant (10 μg/ml) | |
| None (control) | <LODb | <LOD |
| Mitomycin C induced | 470 | 800 |
| Metronidazole induced | 405 | 390 |
| Carbadox induced | 250 | 820 |
VSH-1 virions were induced by treating NT cultures of B. hyodysenteriae strain A203 (Tyr Cmr) with mitomycin C (20 μg/ml), metronidazole (1 μg/ml), or carbadox (1 μg/ml). Purified virions (containing 1 to 2.5 μg DNA) were added to B. hyodysenteriae B78 (Tys Cms) cultures. The values represent average numbers of resistant CFU per total numbers of CFU as determined in two experiments using two VSH-1 preparations for each treatment.
LOD, limit of detection. Spontaneously occurring tylosin-resistant cells were too few for accurate estimates (i.e., 2 to 4 CFU/108 CFU). Spontaneously occurring chloramphenicol-resistant cells were not detected.