Expression of virulence factors by classical and El Tor Vibrio cholerae in vivo and in vitro

Abstract We examined the production of virulence factors of Vibrio cholerae O1 bacteria, and especially compared expression in vitro under near optimal growth conditions with that in vivo during experimental cholera infection. The results show that the in vitro formation of cholera toxin (CT), soluble hemagglutinin (SHA), colonizing pilus TCP, and the biotype associated hemagglutinins FSHA and MSHA, as well as of various cell envelope antigens often rather poorly reflected expression in vivo. For instance, production of CT by vibrios of classical biotype and of TCP by the El Tor biotype were enhanced in vivo, while production of SHA was instead suppressed. Likewise significant differences in cell envelope antigen composition were found between bacteria grown in vivo and in vitro. A more precise definition of the role of different postulated virulence factors in the processes of infection and immunity should include in vivo studies as outlined by this study.     

Starvation survival of the fish pathogenic bacteria Vibrio anguillarum and Vibrio salmonicida in marine environments

Abstract The possible fate in sea water of the two fish pathogenic bacteria Vibrio anguillarum and Vibrio salmonicida is discussed on the basis of microcosm experiments with these and other copiotrophic bacteria. Recent articles dealing with the survival of fish pathogens are reviewed, and the reported survival capacities are discussed in relation to ecological mechanisms, such as death, and predation, leading to the removal of bacteria from the water column.