Non-Selectivity of R-S Media for Aeromonas hydrophila and TCBS Media for Vibrio Species Isolated from Diseased Oreochromis niloticus

Abstract

The current study was conducted to determine the bacterial pathogens incorporated in mass mortality observed in cultured Oreochromis niloticus farms at Kafrelsheikh province, Egypt, during the summer season of 2015. Moribund fish samples were collected from six infected farms. General signs of septicemia were dominant in the clinical and gross internal examination of diseased fish. The pathogenic bacteria were isolated on specific media then confirmed by polymerase chain reaction (PCR). Out of thirty isolates, nineteen Aeromonas hydrophila, seven Vibrio cholera and three Vibrio alginolyticus isolates were recovered and identified using PCR. Current study indicated non-selectivity of Rimler-Shotts media for selective isolation of Aeromonas hydrophila also non-selectivity of TCBS media for Vibrio spp. isolated from diseased Oreochromis niloticus.