Virulence of Vibrio harveyi responsible for the 鈥淏right-red鈥?Syndrome in the Pacific white shrimp Litopenaeus vannamei

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• 作者：Sonia A. Soto-Rodriguez^a ; ^{ssoto@ciad.mx} ; Bruno Gomez-Gil^a ; Rodolfo Lozano^a ; Rodolfo del Rio-Rodrí ; guez^b ; Ana L. Dié ; guez^c ; Jesú ; s L. Romalde^c
• 关键词：&ldquo ; Bright-red&rdquo ; Syndrome ; Vibrio harveyi ; Shrimp ; Pathogenicity ; Histopathology ; Antibiotics ; Extracellular products
• 刊名：Journal of Invertebrate Pathology
• 出版年：2012
• 期刊代码：120_00222011
• 类别：abs
• 出版时间：March, 2012
• 卷：109
• 期：3
• 页码：307-317
• 文件大小：2297 K

摘要

Vibrio harveyi (Vh) CAIM 1792 strain was isolated from Litopenaeus vannamei affected with 鈥淏right-red鈥?Syndrome (BRS). The strain grew in 1-10%NaCl, at 15-35 掳C and was resistant to ampicillin (10 渭g), carbenicillin (100 渭g) and oxytetracycline (30 渭g). The lowest MIC was for enrofloxacine (0.5 渭g ml^鈭?). The in vivo and in vitro toxicity of bacterial cells and the extracellular products (ECPs) of Vh CAIM 1792 grown at 1.0%, 2.0%and 4.0%NaCl were evaluated. Adherence ability, enzymatic activities and siderophore production of bacterial cell was tested. The ECPs exhibited several enzymatic activities, such as gelatinase, amylase, lipase, phospholipase and caseinase. These ECPs displayed a strong cytotoxic effect on HELA cell line at 6 and 24 h. Challenges using 10³ CFU g^鈭? caused opacity at the site of injection and over 80%shrimp mortality before 24 h p.i. (post-injection). Mortality caused by the ECPs was higher than mortalities with bacteria, especially in the first hours p.i. Bacteria were re-isolated from hemolymph samples of moribund shrimp and identified as Vh CAIM 1792 by rep-PCR. Histological analysis of shrimp L. vannamei injected with Vh CAIM 1792 revealed generalized necrosis involving skeletal muscle (MU) at the injection site, the lymphoid organ (LO), heart and connective tissues. Melanization within the MU at the site of injection was also observed as well as hemocytic nodules within the hearth and MU at 168 h p.i. LO was the target organ of BRS. Necrosis of the MU at the injection site was the main difference in comparison to other shrimp vibriosis.