Modelling streptococcal urogenital tract infection to study mechanisms of bacterial colonization and persistence (2007–2009)
Colonization of the urogenital tract with bacterial pathogens is one of the most common infections in humans. In Australia millions of people are colonized in their urogenital tracts at any given time, often asymptomatically, and many such individuals require medical intervention for the treatment of consequent infections that result from persistent colonization. Bacterial colonization of the urogenital tract is associated with a variety of disease presentations including urinary tract infections and neonatal infections resulting from vertical transmission of colonizing bacteria from mothers to newborns. Aside from sexually-transmitted diseases the most prominent bacterial pathogens that colonize the urogenital tract are Group B Streptococcus (GBS) and Escherichia coli. GBS in particular exist in the female urogenital tract as a persistent microbial reservoir in up to 40% of pregnant women and are transmitted to newborns in up to 72% of live births. Colonization of newborns leads to invasive disease including pneumonia, sepsis, and meningitis. While the disease presentations resulting from colonization of the urogenital tract vary the underlying basis that leads to disease is antecedent bacterial persistence in the urogenital tract despite immune system activation. The mechanisms whereby GBS evade immune responses in the urogenital tract to allow their survival are unknown. I will define the immune-evasion mechanisms and virulence traits used by GBS, as a model urogenital pathogen, to successfully colonize the urogenital tract in the face of mounting immune responses. These studies will provide a better understanding of the pathogenesis of urogenital disease in terms of bacterial colonization and immune-evasion strategies. This will shed light onto new approaches for the prevention and treatment of urogenital disease in humans such as improved vaccination, locally acting cytokines, and deliberate colonization with non-invasive strains for the prevention of disease.