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Studies on the pathogenesis of streptococcal infection in cultured yellowtails Seriola spp.: the fate of Streptococcus sp. bacteria after inoculation
Author(s) -
KUSUDA RIICHI,
KIMURA HAJIME
Publication year - 1978
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/j.1365-2761.1978.tb00009.x
Subject(s) - biology , bacteria , microbiology and biotechnology , inoculation , streptococcus , pathogenesis , virulence , colony forming unit , immunology , biochemistry , genetics , gene
. The causative agent of streptococcal infection of yellowtails has been isolated but no information is presently available with respect to the mechanism of infection. The present study deals with the growth of the bacteria in the fish body at various periods after either per‐oral or per‐cutaneous challenge with Streptococcus sp. YT‐3 strain at different passage levels. After percutaneous challenge with bacteria of high virulence, the kidneys retained the bacteria with the relatively high count of 10 7 cells per gram of tissue while in other organs, although high concentrations of 10 5 ‐10 6 cells were detected in 10 min, this was followed by a progressive decrease up to 24 h post‐inoculation with a subsequent rapid increase during the later stages of the disease process. The highest rate of growth was obtained in the intestine, where 10 7 cells were detected at 72 h after inoculation. After oral challenge, the bacteria were detected at high levels from organs and blood within 10 min but they were completely removed from all organs except the intestine within 24 h.