Debra Bessen, Ph.D.
Professor of Microbiology and Immunology
Email:
Address:
Dept. of Microbiology & Immunology
Basic Sciences Building
New York Medical College
Valhalla, NY 10595
Personal Profile:
1990 - 1992, Assistant Professor, Bacterial Pathogenesis & Immunology, Rockefeller University, NY, NY
1992 - 1996, Assistant Professor, Epidemiology & Public Health, Yale University, New Haven, CT
1997 - 2001, Associate Professor, Epidemiology & Public Health, Yale University, New Haven, CT
2002 - 2003, Research Scientist, Ecology & Evolutionary Biology, Yale University, New Haven, CT
2003 - 2004, Associate Professor, Microbiology & Immunology, New York Medical College
2004 - present, Professor, Microbiology & Immunology, New York Medical College
Professional Interests:
Our research is primarily focused on group A beta-hemolytic streptococci (Streptococcus pyogenes), which are among the most prevalent of bacterial pathogens; humans are its sole biological host. A hallmark feature of S. pyogenes is its molecular and biological diversity among strains. Although S. pyogenes infection can produce serious illness, such as autoimmune and severe invasive disease, most often it causes only a mild disease at superficial tissue sites - the oropharynx (strep throat) or epidermis (impetigo). The throat and skin are the primary tissue reservoirs for S. pyogenes, whereby the organism is most successful in reproductive growth and transmission to new hosts. Based on decades of field work, it has become widely recognized that many strains differ in their tissue site preference, giving rise to the concept of distinct throat and skin strains. Our long-term goals include understanding the underlying genetic organization of S. pyogenes, and determining the molecular basis for throat- and skin-specific infections. Our approach integrates the disciplines of population genetics and molecular pathogenesis.
In another major area of inquiry, we are investigating the role of group A streptococcal infections in triggering acute episodes of common neuropsychiatric disorders in children (Tourette's syndrome and chronic tic disorders, obsessive-compulsive disorder), via an autoimmune mechanism.
Bessen Lab website is at www.bessenlab.org.
Projects on streptococci include:
1. Multi-locus sequence typing (MLST). Go to www.mlst.net for data and tools.
2. Characterizing the role of streptococcal genes in tissue tropisms, by testing genetic mutants of S. pyogenes in a humanized mouse model for skin infection. The streptococcal products under study include a secreted cysteine proteinase (SpeB), a plasminogen activator (streptokinase), a plasminogen-binding surface protein (PAM), extracellular matrix-binding surface proteins, and global regulators of transcription.
3. The development and testing of predictive models that can aid in the design of effective vaccines, by assessing the impact of selection by the host immune response, through examination of its imprint on the bacterial population genetic structure.
4. Understanding the molecular evolutionary processes underlying niche adaptation, with a special focus on recombinational replacements by orthologous genes.
5. Deciphering the molecular evolution of antibiotic resistance.
6. Assessing immunological changes in pediatric patients with tics or OCD, in correspondence with changes in the clinical severity of neuropsychiatric symptoms.
Education Profile:
Post Graduate Studies The Rockefeller University
Graduate Degree: Ph.D.
Graduate Degree Institution: The Rockefeller University
Undergraduate Institution: Hampshire College
Selected Bibliography:
Lizano, S., F. Luo and D.E. Bessen, 2007. Role of streptococcal T-antigens in superficial skin infection. J. Bacteriol. 189: 1426-1434.
Kratovac, Z., A. Manoharan, F. Luo, S. Lizano and D.E. Bessen, 2007. Population genetics and linkage analysis of loci within the FCT region of Streptococcus pyogenes. J. Bacteriol. 189: 1299-1310.
Wertz, J.E., K.F. McGregor and D.E. Bessen, 2007. Detecting key structural features within highly recombined genes. PLoS Comp. Biol. 3: 137-150.
Robinson, D.A., J.A. Sutcliffe, W. Tewodros, A. Manoharan and D.E. Bessen, 2006. Evolution and global dissemination of macrolide resistant group A streptococci. Antimicrob. Agents & Chemo. 50:2903-2911.
Luo, F., J.F. Leckman, L. Katsovich, D. Findley, H. Grantz, D.M. Tucker, P.J. Lombroso, R.A. King and D.E. Bessen, 2004. A prospective longitudinal study of children with tic disorders and/or obsessive-compulsive disorder: Relationship of symptom exacerbations to newly acquired streptococcal infections. Pediatrics 113: e578-e585.