Relation between virulence and presence of plasmids in bacteria Vibrio fluvialis and Vibrio furnissi isolated from goldfish (Carassius auratus)

Abstract

BACTERIAL STRAINS WERE ISOLATED FROM KIDNEYS OF ORNAMENTAL FISH OF THE CARASSIUS AURATUS SPECIES. TWO BACTERIAL FAMILIES OF ICTIOPATHOGENIC RELEVANCE WERE PRESUMPTIVELY IDENTIFIED: AEROMONADACEAE AND VIBRIONACEAE, THROUGH THE API-20E, API-20NE METHODS. THE IDENTITY OF THESE BACTERIA WAS CONFIRMED THROUGH COMPLEMENTARY BIOCHEMICAL TESTS. THE PRESENCE OF AEROMONAS HYDROPHILA AND TWO DIFFERENT STRAINS OF THE GENUS VIBRIO: VIBRIO FL UVIALIS AND VIBRIO FURNISSII WERE ALSO CONFIRMED USING THE POLYMERASE CHAIN REACTION. WE CONFIRMED THE ABILITY OF THE VIBRIO SPECIES TO INDUCE INFECTION IN HEALTHY SUSCEPTIBLE FISH OF THE SPECIES CARASSIUS AURATUS, ACCORDING TO KOCH'S POSTULATES. THE STRAINS OF BOTH SPECIES WERE CULTURED IN AGAR- BLOOD PLATES, OBSERVING'-HEMOLYSIS IN 97% OF THE GROWN STRAINS. ALKALINE DNA EXTRACTION YIELDED R-PLASMIDS IN 87.5 % OF THE ISOLATED STRAINS WITH MOLECULAR WEIGHTS FROM 25 000 BP TO 6 000 BP. THE RELATION BETWEEN THE -HEMOLYTIC CAPACITY OF THE STUDIED STRAIN AND THE PRESENCE OF PLASMIDS WAS CONFIRMED BY THE LACK OF HEMOLYSIS IN AGAR-BLOOD PLATES AND THE INABILITY TO PRODUCE INHIBITION HALOS IN THE ANTIBIOTICS TEST, AFTER CURING THE PLASMIDS WITH ACRIDINE-ORANGE.