2.2. Biochemical tests
Twenty-six putative E. ictaluri isolates (whitish, pinpoint colonies) were cultured on BHIA at 28 °C for 48 h and then subjected to biochemical characterization. Gram staining was conducted and the bacterial morphology was examined under a light microscope (Zeiss, Jena, Germany). Oxidase and catalase tests were conducted on all 26 isolates, as described by Crumlish et al. (2002). Other biochemical tests were performed using the API 20E kit (bioMérieux, Marcy l’Etoile, France), following the manufacturer’s instructions.