الفهرس | Only 14 pages are availabe for public view |
Abstract The present study was planned to investigate streptococcosis in cultured and wild Nile tilapia. The studies were carried out on 160 Nile tilapia. The clinical picture was darkening of skin, opacity in the eye, haemorrhages in different parts of body with presence of detached scales. 20 bacterial isolates of Streptococcus faecalis were detected. The prevalence was high in summer season (44%) than winter (8%) to gain total prevalence (18%) all over the year. Kidney was the most common organ where44.4% of Streptococcus species were located. The antibiogram revealed that the isolates were sensitive to oxytetracycline and chloramphenicol, and resistant to ampicillin, erythromycin, nalidixic acid, neomycin, streptomycin, kanamycin and sulphaltrimethoprim. Experimentally infection with Streptococcus faecalis caused nearly the same clinical signs found. The mortalities were observed among fish infected by dipping in the bacterial suspension with skin scrafication and by intraperitoneal injection. . |