Profile - Doug Mitchell -Mellon College of Science - Carnegie Mellon University

Pharmacology Researcher: Doug Mitchell

photo of Doug Mitchell

B.S., Chemistry, 2002

Occupation: Postdoctoral fellow, Department of Pharmacology, the University of California, San Diego School of Medicine

Doug Mitchell thinks that it might be a more diplomatic strategy to disarm bacteria rather than kill them, and his efforts have uncovered a wealth of potential targets for novel antibiotics to fight childhood disease. Mitchell, a 2002 chemistry graduate who is now a postdoctoral fellow conducting research in the Department of Pharmacology at the University of California, San Diego School of Medicine, is working to develop a new therapeutic strategy to combat the notorious pathogen, Streptococcus pyogenes, which causes strep throat, among other diseases. Children are especially prone to strep infections, as indicated by 2.5 million visits to pediatricians annually in the United States alone.

Strep produces a complex polypeptide known as streptolysin S (SLS), a toxin also linked to diseases such as toxic shock, a skin infection called impetigo, and necrotizing fasciitis, better known as the "flesh-eating disease." Mitchell is studying how this toxin is produced by bacteria, in hopes of discovering how to take out a critical component and render it ineffective. In these efforts, Mitchell and colleagues have discovered that many bacterial pathogens biosynthesize toxins structurally related to SLS, leading to the belief that many diseases could be treated by targeting toxin production.

"All antibiotics now in clinical use or in development target essential life processes of the bacteria," said Mitchell. He added that the bacteria are pressured into developing drug resistance if such a vital process is inhibited, so a more thoughtful strategy is to target virulence and remove the bacteria's ability to cause disease in its host, or, as he puts it, "Let them live, but make them incapable of infecting humans."

Mitchell and colleagues have devised a way to attenuate the SLS toxin, a finding that could potentially lead to a strep vaccine, which stands to benefit more than just humans. A highly related bacterium, Streptococcus iniae, infects fish and devastates the food supply in countries that rely on fish as the cornerstone of their dietary needs.

Mitchell was recently selected by UC San Diego to receive a Hartwell Fellowship, which provides support of his research for two years at $50,000 per year.  The support is made possible by The Hartwell Foundation to enable scientists in the early stages of biomedical research careers to pursue further specialized training as part of their career development.

Excerpted from UC San Diego press release. Photo courtesy of UC San Diego.

Update: Doug Mitchell is currently an assistant professor of chemistry at the University of Illinois.