Effects of Physicochemical Factors and Bacterial Colony Morphotype on Association of 'Vibrio vulnificus' with Hemocytes of 'Crassostrea virginica'

摘要

Vibrio vulnificus is a naturally occurring marine bacterium which causes invasive disease of immunocompromised humans following consumption of raw oysters. It is natural flora of Gulf Coast estuaries and has been found to inhabit tissues of oysters, Crassostrea virginica (Gmelin, 1791). The interaction of V. vulnificus with oyster host defenses has not been reported in detail. In the present studies, we examined the interaction of V. vulnificus with phagocytic oyster hemocytes in response to time, temperature, bacterial concentration, pretreatment in hemolymph, and with V. vulnificus translucent and opaque colonial morphotypes. Within these experimental parameters, results showed that association of V. vulnificus with hemocytes increased with time, temperature, and V. vulnificus:hemocyte ratio. Pretreatment of V. vulnificus with serum, or increased serum concentration, did not enhance V. vulnificus-hemocyte associations, indicating undetectable opsonic activity. More than 50% of hemocytes bound the translucent, avirulent morphotype, whereas 10% to 20% were associated with the opaque, virulent form. (Copyright (c) 1993, American Society for Microbiology.)