| Autor: |
Faisal, Mohamed, La Peyre, JeromeF., Elsayed, Ehab, Wright, D.Craig |
| Zdroj: |
Journal of Aquatic Animal Health; June 1999, Vol. 11 Issue: 2 p130-138, 9p |
| Abstrakt: |
AbstractThe in vitro growth rates of two isolates of Perkinsus marinuswere significantly reduced by bacitracin. Upon coincubation with 1 mg bacitracin/mL, the doubling times rose from 27 ± 2.1 h to 34 ± 2.9 h for the LMTX-1 isolate (P< 0.001) and from 15 ± 1.9 h to 22.2 ± 2.4 h for the Perkinsus-1 isolate (P< 0.001). At 10 mg bacitracin/mL, viability of both isolates was much reduced (P< 0.0001). The sensitivity of P. marinusto bacitracin was examined in vivo in two clinical trials. In the first, individual eastern oysters Crassostrea virginicawere injected with 107Perkinsus-1 cells, then fed bacitracin at a concentration of 5 or 50 mg/mL encapsulated in lipid vesicles daily for 6 weeks. Parasite body burden was significantly reduced in oysters administered 5 mg bacitracin/mL (3.3 × 104± 2.5 × 104hypnospores/g wet tissue) or 50 mg/mL (5.3 × 104± 6.4 × 104hypnospores/g) as compared with control oysters (3.2 × 105± 4.7 × 105hypnospores/g, P< 0.05) that received encapsulated seawater only. In the second experiment, naturally infected oysters (average, 10.9 × 106± 30.7 × 106hypnospores/g) received encapsulated bacitracin at 10 mg/mL for 10 weeks. Treated oysters had significantly lower levels of infection (2.5 × 106± 3 × 106hypnospores/g) than did control oysters (67.4 × 106± 144 × 106hypnospores/g, P< 0.05). Despite the sharp decrease in infection intensity in the bacitracin-treated oysters, survival rate improved by only 10%. It is possible that damage to the vital organs of infected oysters was too advanced and widespread to be reversed. The in vitro and in vivo findings of this study suggest that bacitracin has promise for use in P. marinuschemotherapy. |
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