A novel TTX-producing Aeromonas isolated from the ovary of Takifugu obscurus

Puffer fish ( Takifugu obscurus) from the Yangtze River of China were screened for tetrodotoxin-producing bacteria. An Aeromonas strain was isolated from the ovary of the puffer fish and was shown to produce tetrodotoxin; this strain was denoted Ne-1. The identity of tetrodotoxin produced by strain Ne-1 was confirmed by mouse bioassay, high performance liquid chromatography coupled with mass chromatography (LC-MS), and ELISA. Strain Ne-1 was characterized morphologically, biochemically, and by 16S rDNA phylogenetic analysis; these analyses suggested that strain Ne-1 is closely related to Aeromonas molluscorum. Given that strain Ne-1 was isolated from the ovary of T. obscurus, we propose that the TTX-producing Aeromonas sp. is a parasite or symbiotic bacterium rather than a sample contaminant. Collectively, our studies suggest that Aeromonas sp. strain Ne-1 produces tetrodotoxin in T. obscurus.