M.D., Ph.D, Washington University School of Medicine, 2000
My laboratory is interested in understanding the bacterial factors that promote successful colonization by the diverse population of pneumococci. This organism spends majority of its life in the polymicrobial environment of the nasopharynx where it is exposed to attack by the host immune system as well as by other inhabiting or invading organisms. Although the interaction of the bacteria with the host immune system in controlling or modifying colonization has been the focus of intense study by others, the role of inter-bacterial interactions that impact successful colonization in a polymicrobial environment are less well understood. We have recently identified a heterogeneous locus in pneumococcus encoding antimicrobial peptides called pneumocins. These peptides target unrelated pneumococci as well as other members of the respiratory flora and presumably give producing strains an advantage during colonization. We have shown that these peptides are produced during murine colonization, allowing producing strains to out-compete sensitive competitors.