[Clinical Aeromonas hydrophila contain the DNA fragments with nucleotide sequence similar to those of hemolysin and cholera-toxin gene].
The artificially synthesized aquatic Aeromonas hydrophila partial aerolysin gene DNA (Ae, containing 48 oligonucleotides), and partial cholera-toxin gene DNA fragments (C1 and C2, containing 34 and 19 oligonucleotide, respectively) were used as probes to determine their DNA sequence homology to the chromosome DNA of 191 strains of the clinically isolated A. hydrophila, using the colony hybridization test. The three probes had a positive reaction with clinical A. hydrophila strains. Several positive strains of this organism were further screened by cutting reaction with restriction endonuclease BamHI and EcoRI, the alkaline Southern transfer, and DNA hybridization test. Some strains were found to be positive in reacting with Ae and C1, but negative with C2. The findings led to the conclusion that the DNA sequences were homologous among the clinical A. hydrophila toxin gene, cholera-toxin gene and aquatic A. hydrophila aerolysin gene.