Shigella and Antivirulence: the Dark Side of Bacterial Evolution
Kimberly A. Bliven and Anthony T. Maurelli
from: Shigella: Molecular and Cellular Biology (Edited by: William D. Picking and Wendy L. Picking). Caister Academic Press, U.K. (2016) Pages: 49-64.
The acquisition of novel virulence factors and subsequent remodeling of bacteria systems to incorporate these factors are equally important events in pathogen evolution. Genes that are inactivated or lost from an emerging pathogen's genome due to incompatibility with new virulence factors are known as antivirulence genes (AVGs). AVGs were first described in Shigella, a human-specific gastrointestinal pathogen that evolved from ancestral Escherichia coli. Although AVGs have been described in a variety of bacterial pathogens, including Salmonella, Yersinia, Burkholderia, and Francisella, Shigella remains perhaps the best model organism for the study of antivirulence due to the vast extent of literature on not only Shigella, but also E. coli, which retains the functional AVGs that have been inactivated or lost in Shigella strains. Currently, there are five documented AVGs in Shigella: cadA, nadA/nadB, speG, and ompT. In this chapter, we will discuss the discoveries of these AVGs, their effects on virulence, and the events that led to their inactivation or loss in Shigella. The development of novel therapeutics and vaccines, an improved understanding of virulence mechanisms, and a greater insight into pathogen evolution are just some of the benefits that may arise from exploration of AVGs in bacterial pathogens read more ...