Phenotypic and genotypic characterization of Streptococcus species isolated from fish / Nehal Mohamed Fawzy Elsayed Mahmoud ; Supervised Kamelia Mahmoud Osman Ahmed , Mai Eldesoky Elsaid Ibrahim , Mohamed Naguib Mohamed Ali

Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Microbiology

The prevalence of streptococcus species isolated from a total number (80) of tilapia fish was 21.25% with total number of isolates 17 (6 isolates of E. faecalis (7.5%), 3 isolates of S. pluranimalium (3.75%), 2 isolates of A. viridans and E. gallinarum (2.5% for each), one isolate of S. dysgalactiae, S. anginosus, L. garvieae and Granulicatella elegans (1.25% for each)). Isolates were tested for growth in different environmental conditions 210{u00B0} C, 45{u00B0} C, 6.5% salinity and 40% bile salts3 Streptococcus anginosus and Streptococcus dysgalactiae showed no growth at 10{u00B0}C, Enterococcus gallinarum and Streptococcus anginosus showed no growth at 45{u00B0}C, Lactococcus garvieae, Streptococcus dysgalactiae and Streptococcus anginosus showed no growth in 6.5% salinity, and none of the isolates could grow in 40% bile salts. Isolates were identified biochemically using 2Vitek3 and the results were confirmed by applying PCR technique using by the guidance of the specific 16s rRNA primers for Enterococcus species, S. pluranimalium, L. garvieae, S. anginosus, and A. viridans. Species specific gene 2ddl E. faecalis3 was identified in 100% of E. faecalis isolates

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