The Evolution of Vibrio cholerae as a Pathogen

Abstract

Vibrio cholerae is the causative agent of cholera, a severe gastrointestinal infection that is a major public health problem in developing countries where water quality and sanitation are poor. Not all strains of V. cholerae are highly pathogenic for humans and genetic analysis has shown that the difference between pathogen and nonpathogenic strains resides in their virulence gene content. In this chapter, I will review the field’s knowledge of the major virulence factors of V. cholerae,the genetic elements that encode them, and the evolutionary process that leads to the emergence of toxigenic V. cholerae. Ecological factors (e.g., lytic phage sensitivity, chitin utilization, and quiescent environmental states) will not be discussed in this chapter given that these aspects of V. cholerae biology will be discussed in detail in other chapters. Instead, this chapter will focus on aspects of the organism that relate to its evolution as a pathogen with emphasis on its known and putative virulence factors, the genetic elements that encode them, and how this knowledge has shaped cholera vaccine development efforts.