Study of gross and histopathological changes in Cyprinus carpio infected by non- hemolytic Streptococcus Part 1: Isolation and Identification of non-hemolytic Streptococcus

Abstract

Twenty four of non- hemolytic Streptococcus was isolated from thepond of healthy carp of Marine Science Center- Basrah University.The bacteria were identified depending on colonies morphology ofgrowing isolates on Brain Heart Infusion (BHI) agar. Colonies weresmall, round and convex shape. The cells of non- hemolyticStreptococcus were Gram positive, and may occur in pairs or chains.The cells are spherical or ovoid shape and small.Sixty fishes of common carp (Cyprinus carpio) were obtained fromthe farm of Marine Science Center, University of Basrah. Thesefishes were divided into six groups (10 fishes/20 liters aquaria). Oneof those groups was injected intraperitoneally (I.P.) with an isolate ofnon-hemolytic Streptococcus at a concentration of 1 X 104 CFU/ ml.The other two groups were inoculated with 2.5 X 107 CFU/ ml of thesame isolate via water pollution, one with and the other without skinabrasion. The other three groups were left as control and theexperimental period was 35 days. The mortality rate was 100% inthe I.P. injected group during the first week of the experiment, whilenil in the other groups.