Isolation and Identification of Pathogenic Cocci Form Bacteria of Rainbow Trout (Oncorhynchus mykiss) in Fish Farms in North West Province of Fars, Using Culture and PCR Methods
Subject Areas : Journal of Animal Biologyفرشید کفیل زاده 1 , یلدا بناکار 2 , ایرج نامداری 3
1 - دانشگاه آزاد اسلامی، واحد جهرم، گروه زیست شناسی، جهرم، ایران.
2 - دانشگاه آزاد اسلامی، واحد جهرم، گروه زیست شناسی، جهرم، ایران.
3 - استادیار، اداره کل دامپزشکی شیراز، شیراز، ایران
Keywords: PCR, Rainbow trout, Lactic acid bacteria, Streptococcus milleri,
Abstract :
Streptococcosis /Entrococcosisis important disease in aquaculturewhich are duo to gram positive bacteria such as cocci in fresh and salty water fish and cause infectious and septicemia. In recent decades the mentioned diseases caused economic damages. One of the most important cocci are lactic acid bacteria. They invaded to fish farms and caused to death of them. The aim of this research was identification of gram positive and pathogenic cocci form bacteria in rainbow trout farms in North West area of Fars province by cultivation and PCR methods. At first 90 samples of rainbow trout were collected from farms where might be contaminated. Then dead and sick fish were identified and their clinical profiles were recorded. Sampling from their kidney was done for cultivating bacteria and doing biochemical test to identify them. In the next step for determination of antibiotic that was effective on identified bacteria antibiogram test was done. At the end identification of bacteria was done by PCR method in the base of 16srRNA gene. In this research 43 gram positive cocci were identified they included: 4.6% Streptococcus iniae, 23.3 % Lactococcus graviae, and 72.1 % Streptococcus milleri. The result of PCR test showed that identified bacteria belonged to lactic acid bacteriathat caused diseases in the fish. As regards the diseases are common between human and aquaculture and they cause economical damages so identification and treatment of these infectious agents are important. Clinical symptoms of bacteria which cause the diseases are similar so the best method for identification of them is PCR.