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Pathogenicity of live bacteria and extracellular products of motile Aeromonas isolated from eels
Author(s) -
Esteve Consuelo,
Amaro Carmen,
Garay Esperanza,
Santos Y.,
Toranzo Alicia E.
Publication year - 1995
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1995.tb03099.x
Subject(s) - microbiology and biotechnology , aeromonas hydrophila , hemolysin , biology , virulence , aeromonas , pathogenic bacteria , bacteria , vibrionaceae , extracellular , gene , biochemistry , genetics
The pathogenic activities in vitro and in vivo of live bacteria and extracellular products (ECP) of 24 motile Aeromonas strains were investigated. Most Aer. hydrophila and Aer. jandaei isolates were pathogenic for eels (LD 50 10 5·4 ‐10 7·6 cfu fish ‐1 ) but no Aer. sobria , Aer. caviae and Aer. allosaccharophila caused mortality in eels at doses of > 10 8·4 cfu fish ‐1 . Of these Aeromonas strains, Aer. hydrophila and Aer. jandaei in particular produced elastases and haemolysins against fish erythrocytes. ECP from Aer. hydrophila and Aer. jandaei caused degenerative changes in fish cell lines and were strongly toxic for eels (LD 50 1·0–3·2 μg (g fish) ‐1 ) reproducing the symptoms associated with natural disease. ECP from non‐pathogenic species were inactive on fish cell lines as well as being poorly lethal for eels (LD 50 > 9·2 μg (g fish) ‐1 ). All these biological activities of Aeromonas ECP were lost after heat treatment. These findings indicate differences between pathogenic and non‐pathogenic Aeromonas species with respect to the expression of virulence factors, and show that elastases, haemolysins and exotoxins play a leading role in the pathogenicity of motile Aeromonas for eels.