Research Interests

My primary interest as a marine microbiologist has been to understand the two life styles of an epidemic-causing diarrhea pathogen Vibrio cholerae in its host environment as a pathogen and in its free-living state in the aquatic environment. This rather unconventional approach has enabled me to study another important process that relates to the emergence of new variants of this organism that has been induced by selective pressures in the environment as well as in the host. Following this approach has allowed my colleagues and I to discover the evolution of new variants of enteric pathogens in an endemic setting, the most famous of which was the discovery of the new serogroup that causes cholera, namely, Vibrio cholerae O139 Bengal. We were also associated with the discovery of the new pandemic serogroup Vibrio parahaemolyticus and many new variants of Shiga-producing Escherichia coli (STEC). I have begun dabbling with the gastric pathogen Helicobacter pylori, which has a nonepidemic mode of transmission in contrast with that of Vibrio cholerae. Understanding the evolution of bacterial pathogens that have two entirely different modes of transmission will provide new insights into how these pathogens outwit their human hosts.

Membership Type

International Member

Election Year


Primary Section

Section 27: Evolutionary Biology

Secondary Section

Section 63: Environmental Sciences and Ecology