Isolation of Bdellovibrio as Biological Therapeutic Agents Used For the Treatment of Aeromonas hydrophila Infection in Fish

Abstract

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.

The dual probiotic and antibiotic nature of Bdellovibrio bacteriovorus

“…This was demonstrated within a recent study done by Chu and Zhu (2010), where a strain by B. bacteriovorus (BdC-1) effectively protected cultured fish in ponds against an experimental infection of A. hydrophila J-1 (47). The mortality of groups immersed with BdC-1 was lower than the groups without BdC-1 addition, which in turn strongly illustrates the possible use of BALOs to control infectious bacteria within lakes and ponds.…”

Bdellovibrio and Like Organisms

“…BALOs have been isolated from the gills of crabs, sediments, submerged surfaces, soils, rice paddies, the rhizosphere of plants, and fish ponds (Chu and Zhu 2009;Kelley et al 1997;Uematsu 1980;Williams et al 1995) (Jurkevitch et al 2000;Stolp and Starr 1963). They have been isolated from animal feces (Schwudke et al 2003) and detected as forming dominant populations in the leech Hirudo verbana (Kikuchi et al 2009).…”

Predation Efficacy of <i>Bdellovibrio bacteriovorus</i> on Multidrug-Resistant Clinical Pathogens and Their Corresponding Biofilms

“…Its promising ability to reduce bacterial populations is linked to its application as a biocontrol agent to clear different habitats of plant, fish, and food-borne pathogens (17,18). Moreover, it has been proposed that B. bacteriovorus 109J can be used as a probiotic bacterium because of its ability to prey on gram-negative bacteria and their biofilms (19).…”