سال انتشار: ۱۳۸۷

محل انتشار: اولین کنگره بین المللی مدیریت بهداشتی و بیماریهای آبزیان

تعداد صفحات: ۱

نویسنده(ها):

Z Sattari Najafabadi – Faculty of Veterinary Medicine, Shahrekord University
S Shahrokh –
H Malekyan –
A Nematolahi –

چکیده:

Objective: Different genera and species of gram-positive, catalase-negative cocci are pathogenic to fish. The numbers of infections caused by these microorganisms have increased during the last decade as a consequence of the intensification of aquaculture, and such infections are responsible for significant economic losses in the fish farm industry. Streptococcus iniae has been recognized as a cause of human and fish streptococcosis which is a hemolytic, gram-positive coccus. It causes meningoencephalitis in tilapia, yellowtail, rainbow trout, and coho salmon and has been associated with disease outbreaks in aquaculture farms with mortality rates of up to 50%.
Method & Materials: In common with other encapsulated betahaemolytic streptococci and in direct contradiction to the phenomenal success story of bacterial vaccines in finfish aquaculture, control of Streptococus iniae by vaccination has met with limited success. Thus, antibiotic usage is the current practice for reducing mortality and consequent economic loss. Before choosing an antibiotic a sensitivity test should be performed to ensure that the correct medication is used. A sensitivity test shows the resistance of the disease-causing bacteria to various antibiotics. In this study antibiotic sensitivity was assessed using the disk diffusion assay.
Results & Conclusion: The isolated bacteria from the disease rainbow trouts were seeded in Mueller-Hinton agar. Commercially available disks with the following antibiotics were used: penicillin, kanamycin, novobiocin, amikacin, chloramphenicol, nalidixic acid, bacitracin, methicilin, cloxacilin and cefepime. The bacteria showed resistance to nalidixic acid and cloxacilin. Among the other antibiotics it seemed that the most effective one was choramphenicol and respectively amikacin, bacitracin, cefepime, kanamycin, methicilin, penicillin and novobiocin were after that. Further studies are needed in order to confirm the effectiveness of these antibiotics in vivo situations.