Objective. This investigation aimed to study the presence of Streptococcus spp. in tilapia (Oreochromis niloticus) from fish farm located in Sullana-Piura, Peru. Materials and methods. 150 fish with clinical signs of streptococcal disease were sampled, and the bacterium isolation was performed on blood agar, correlated to histopathological lesions description and molecular confirmation by real-time PCR. Results. The necropsy revealed exophthalmia, hyphema, congestion and/or haemorrhagic meninges, ascites, splenomegaly, hepatomegaly and diffuse haemorrhagic zones throughout the body. 102 isolated positives (54 tilapias) to Streptococcus spp. were identified in the microbiological analysis (prevalence of 26%), the brain was the organ with the highest percentage of this bacteria (34.31%), and 19 isolates were beta-haemolytic (18.63%) with prevalence of 10.12%. Fish beta-haemolytic streptococci presented epicarditis, perisplenitis and chronic meningitis, panophthalmitis, coagulative necrosis of skeletal muscle and granulomas formation. In the confirmatory test by real-time PCR, any positive tilapia to S. iniae was obtained. The results were analysed using a stochastic simulation of beta distribution using @Risk program uncertainty, reporting an average prevalence of 0.66% in sick tilapias. Conclusions. The analysed fishes were positive to bacteria of the genus Streptococcus, which confirms its presence in the fish farm. However, 19 isolates were beta-haemolytic, and the presence of S. iniae was not positive to the limit prevalence of 2.7% in real-time PCR.Keywords: Cichlids, histopathology, microbiology, PCR, teleost fish (Source: DeCS, CAB, MeSH).
Beta-haemolytic streptococci in farmed
RESUMENObjetivo. Esta investigación objetivó estudiar la presencia de Streptococcus spp. en tilapia (Oreochromis niloticus) de la piscifactoría localizada en Sullana-Piura, Perú. Materiales y Métodos. 150 peces con signos clínicos de la enfermedad estreptocócica fueron analizados, el aislamiento bacteriano se realizó en agar sangre, en correlación con las lesiones histopatológicas y diagnóstico molecular mediante PCR en tiempo real. Resultados. A la necropsia se observó exoftalmia, hifema, congestión y/o meninges hemorrágicas, ascitis, esplenomegalia, hepatomegalia y zonas hemorrágicas difusas en todo el cuerpo. 102 aislados positivos (54) tilapias para Streptococcus spp. fueron identificados en el análisis microbiológico (prevalencia del 26%), el cerebro fue el órgano con el más alto porcentaje del género de esta bacteria (34.31%), 19 aislados fueron beta-hemolítico (18.63%), con prevalencia de 10.12%. Peces con Streptococcus beta-hemolíticos presentaron epicarditis, perisplenitis y meningitis crónica, panoftalmitis, necrosis coagulativa del músculo esquelético y formación de granulomas. En el análisis de PCR en tiempo real, no se obtuvo ninguna tilapia positiva para S. iniae. Los resultados se analizaron mediante una simulación estocástica de la distribución beta usando el programa de incertidumbre @Risk, reportando una pr...
