Aeromonas encheleia sp. nov., isolated from European eels

Abstract

Four strains isolated from European eels in Valencia, Spain, were found to constitute a DNA relatedness group which is 0 to 50% related to the 13 species and DNA group 11 of the genus Aeromonas. Phenotypically, these strains have all of the properties that define the genus Aeromonas. However, they differ from the previously described Aeromonas species by three or more properties. The strains are positive for motility, growth at 37 degrees C, indole production, and arginine dihydrolase activity. They exhibit negative reactions in tests for growth at 42 degrees C and in thiosulfate-citrate-bile salts-sucrose medium (Oxoid), Simmons citrate tests, and tests for lysine and ornithine decarboxylase activities. They produce acid from salicin but not from L-arabinose, D-cellobiose, or lactose. All four strains hydrolyze esculin and arbutin but not elastin. They use L-serine as a sole carbon and energy source but cannot utilize L-arabinose, L-arginine, D-gluconate, or L-glutamine. The strains are resistant to ampicillin. The guanine-plus-cytosine content of the DNA is 59.4 to 60.8 mol%. The name Aeromonas encheleia sp. nov. is proposed for these strains; strain S181 (= CECT 4342) is the type strain. This new species is generally not pathogenic for eels or mice.