The long-term goals of my laboratory are to increase our knowledge and understanding of the pathogenicity and transmission of mucosal pathogens. We are currently using two model pathogens in our studies; the Gram-negative, water-borne, intestinal pathogen Vibrio cholerae, which is the causative agent of epidemic diarrhea (cholera) in many areas of Africa and South Asia, and the Gram-positive pathogen Streptococcus pneumoniae, which is a major cause of pneumonia and otitis media throughout the world. Our primary focus is identifying and characterizing those pathogen genes and their protein products that are specifically expressed during various stages of the infectious process. To accomplish this, we employ various molecular and genetic techniques, some of which we have created, and several murine models of infection and transmission. The Figure below provides an example of how we approach this issue for Vibrio cholerae.
Figure 1. The left panel shows Vibrio cholerae attached to intestinal villi; the right panel shows the classical rice water stool of a cholera patient, a ready source of Vibrio that express particular sets of genes associated with transmission.
Because bacteria are extremely efficient and generally express genes only in environments where they are needed, investigation of genes expressed during infection and during transmission is a fruitful endeavor. Specifically, it is providing important data on the growth physiology of V. cholerae and S. pneumoniae at host mucosal sites, pathogenic factors elaborated during infection, transmission factors elaborated at late stages of infection, regulatory proteins which coordinate these events, and host stimuli which induce expression of these genes. In addition to determining the roles that these various proteins play in infection and in transmission, we are also engaged in vaccine development for both V. cholerae and S. pneumoniae.
Review supplemental data from the Camilli Lab