Lakshmi Rajagopal, PhD: Associate Professor of Pediatric Infectious Diseases and Microbiology. Our research interest is to understand signaling events that occur during bacterial disease pathogenesis. The human pathogens that we study are Group B Streptococcus (GBS) and Staphylococcus aureus.
Although both GBS and S. aureus are commensal organisms, these bacteria can also become disease-causing pathogens. GBS are commonly found in the recto-vaginal tract of healthy women but can cause severe invasive disease in human newborns and adults that include elderly, immunocompromised and diabetic individuals. Our studies on GBS are focused on understanding how these bacteria adapt to the environmental niches encountered during their life cycle. Studies from our research have shown that GBS encodes signaling factors such as a serine/threonine kinase; these proteins were previously thought only to exist in higher forms such as eukaryotic organisms. Our research showed that the kinase regulates the expression of the GBS toxin known as hemolysin/cytolysin and also enables the bacteria to adapt to nutrient starvation.
In recent studies, we demonstrated that the kinase affects toxin expression based upon its interaction with a DNA-binding response regulator known as CovR. The interaction between the kinase and CovR represents novel findings in bacterial environmental adaptation. Current research is focused toward identifying the environmental cues/signals that are sensed by these bacteria for regulation of toxin expression and virulence. Like GBS, S. aureus are also Gram-positive bacteria that can cause severe invasive disease in humans. We have recently identified a number of novel genes/signaling factors that regulate toxin expression in S. aureus. Current studies are focused on elucidating how these signaling factors regulate toxin expression and S. aureus virulence. The ultimate goal is to use the information gathered from our research to identify novel compounds that can be used to treat these bacterial infections.
For more information, please visit: http://www.seattlechildrens.org/research/childhood-infections-and-prematurity/rajagopal-lab/