Association of Aeromonas sobria with mortalities of adult gizzard shad, Dorosoma cepedianum Lesueur

Abstract

This report describes an epizootic in a natural population of spawning females of gizzard shad, Dorosoma cepedianum Lesueur, which occurred in the Potomac River (Maryland, USA). Microbiologieal analysis of moribund shad revealed the presence in pure culture in all the organs examined of one bacterium which was identified as Aeromonas sobria by conventional tube and plate tests. The different API-systems used to attempt for a rapid diagnosis of the disease yielded false negative and positive reactions in important differential tests such as ornithine decarboxylase, arabinose fermentation, gelatinase, urease, indole and production of H^S which gave an erroneous identifieation of the shad isolate. The virulence assays in rainbow trout revealed that A. sobria was pathogenic with a mean LDso of 2 X 10^^. Bacterial extracellular products a)so displayed fish lethality and were cytotoxic for poikilothermic and homcothermic cell-lines. Although the source of shad infection is unknown, the physico-chemical conditions of the river, together with the stress associated with the spawning could have been contributing factors in the proliferation of A. sobria indueing this epizootic.

Morfologia e quantificação da microbiota intestinal do curimbatá (Prochilodus lineatus) e do cascudo cinza (Pterygoplichthys anisitsi) cultivados em cativeiro

“…Segundo Toranzo et al (1989) A adesão bacteriana é um fenômeno de interação célula-superficie, e esta propriedade a faz ideal para as análises em MEV (Knutton, 1995;Ringo et al, 2003). A MEV apresenta a vantagem, ao contrário da microscopia eletrônica de transmissão, de possibilitar o exame mais rápido das bactérias aderentes colonizadoras e de áreas mais extensas da superfície celular (Ringo et al, 2003).…”

Aeromonas Causes Severe Skin Lesions in Rainbow Trout (Oncorhynchus mykiss): Clinical Pathology, Haematology, and Biochemistry

“…This was confirmed by our other findings in the brook trout affected on mass in intensive culture, as well as in eel and chub in dam reservoirs. Toranzo et al (1989) found Aeromonas sobria to be associated with outbreaks of fatal disease in gizzard shad (Dorosoma cepedianum) and showed it to be pathogenic to rainbow trout in trhe laboratory.…”

The effect of various Aeromonas bestiarum vaccines on non-specific immune parameters and protection of carp (Cyprinus carpio L.)

“…According to recent classification, various species of motile Aeromonas such as A. hydrophila, A. bestiarum, A. sobria, A. jandaei, A. allosaccharophila, A. veronii have been reported as fish pathogens [6][7][8][9][10].…”