Isolation of Bdellovibrio as biological therapeutic agents used for the treatment of Aeromonas hydrophila infection in fish.
Fourteen strains of Bdellovibrio-like organisms were isolated from cultured fish ponds using Aeromonas hydrophila J-1 as host, one of them formed large plaques after 48 h of incubation at 28 degrees C on a double layer plate, designated as Bdellovibrio C-1. The Bdellovibrio was confirmed by electron microscopy and PCR amplification of Bdellovibrio-specific 16S rDNA. The optimum temperature for the growth of BdC-1 was between 15-37 degrees C and with optimal activity at temperatures of 25-30 degrees C. The ability of BdC-1 to lyse A. hydrophila was similar in the pH range of 6.5 to 8.5. It can lyse 23 Gram-negative bacterial strains comprising three genera of fish pathogens and one strain of Escherichia coli but cannot lyse Gram-positive bacteria such as Bacillus subtillis and Staphylococcus aureus. Immersion of fish in water containing different concentrations of BdC-1 was used in protection against an experimental infection of A. hydrophila J-1. Results show that the mortality of groups immersed with BdC-1 was lower than the group without BdC-1. These results suggest that it may be possible to use Bdellovibrio to control the disease caused by A. hydrophila.
Chu
W-H
WH
Department of Microbiology, School of Life Science & Technology, China Pharmaceutical University, Nanjing, China. churong@yahoo.cn
Zhu
W
W
D016980:Aeromonas hydrophila / Q000502:physiology*; D000818:Animals; D001501:Bdellovibrio / Q000502:physiology*; D018920:Coculture Techniques; D005393:Fish Diseases / Q000382:microbiology* / Q000517:prevention & control; D006054:Goldfish; D016905:Gram-Negative Bacterial Infections / Q000517:prevention & control / Q000662:veterinary*; D013997:Time Factors