Bacillus amyloliquefaciensG1: A Potential Antagonistic Bacterium against Eel-PathogenicAeromonas hydrophila

Abstract

Recent studies have revealed that the use of probiotics is an alternative to control marine aeromonas. However, few probiotics are available againstAeromonas hydrophilainfections in eels. In the present study, a potential antagonistic strain G1 against the eel-pathogenicA. hydrophilawas isolated from sediment underlying brackish water. Its extracellular products with antibacterial activities were shown to be stable under wide range of pH, temperature, and proteinase K. It was initially identified asBacillus amyloliquefaciensusing API identification kits and confirmed to beB. amyloliquefaciensstrain (GenBank accession number DQ422953) by phylogenetic analysis. In addition, it was shown to be safe for mammalians, had a wide anti-A. hydrophilaspectrum, and exhibited significant effects on inhibiting the growth of the eel-pathogenicA. hydrophilabothin vitroandin vivo. To the best of our knowledge, this is the first report on a promising antagonisticBacillus amyloliquefaciensstrain from brackish water sediment against eel-pathogenicA. hydrophila.