Debra E. Bessen, Ph.D., obtained her Ph.D. at The Rockefeller University working on the pathogenesis of Neisseria gonorrhoeae. Her post-graduate work continued at Rockefeller with studies on the development of a mucosal vaccine targeting infection by Streptococcus pyogenes (i.e., group A streptococci). In 1992, Dr. Bessen joined the faculty at Yale University School of Medicine where she further developed a research program on the population biology and pathogenesis of group A streptococci, including their role in childhood neuropsychiatric disorders. Her lab moved to NYMC in late 2003. Dr. Bessen's research continues to focus on group A streptococci and spans a wide range of disciplines: molecular epidemiology, population genetics, bacterial evolution, molecular mechanisms of pathogenesis and vaccine development. Current questions of interest include: What is the underlying genetic organization of this bacterial species? What is a biologically relevant definition for GAS ‘strain?’ What are the molecular determinants of host tissue tropisms at the throat and skin? What are the microenvironmental causes and pathological consequences of antibiotic resistance gene transfer in GAS?

Education

• Ph.D., The Rockefeller University

Honors and Awards

• Grant funding (2021-2024):
  • Macrolide resistance transfer in Streptococcus pyogenes, NIH AI-156226
  • Pilin Genotyping for Group A Streptococci, NIH AI-148983

Research

Dr. Bessen's laboratory conducts research that continues to focus on group A streptococci and spans a wide range of disciplines: molecular epidemiology, population genetics, bacterial evolution, molecular mechanisms of pathogenesis, and vaccine development. The current study questions of interest include: What is the underlying genetic organization of this bacterial species? What is a biologically relevant definition for GAS ‘strain?’ What are the molecular determinants of host tissue tropisms at the throat and skin? What are the microenvironmental causes and pathological consequences of antibiotic resistance gene transfer in GAS?

Publications

• Bessen DE, Beall BW, Hayes A, et. al. "Recombinational exchange of M-fibril and T-pilus genes generates extensive cell surface diversity in the global group A Streptococcus population." mBio, 15(5), (2024) e0069324. doi: 10.1128/mbio.00693-24
• Xie O, Morris JM, Hayes AJ, et. al. "Inter-species gene flow drives ongoing evolution of Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis." Nature communications, 15(1), (2024) 2286. doi: 10.1038/s41467-024-46530-2
• Ferretti JJ, Stevens DL, Fischetti VA, et. al. "Molecular Basis of Serotyping and the Underlying Genetic Organization of Streptococcus pyogenes." , (), (2022) .
• Bessen DE, Smeesters PR, Beall BW, et. al. "Molecular Epidemiology, Ecology, and Evolution of Group A Streptococci." Microbiology spectrum, 6(5), (2018) . doi: 10.1128/microbiolspec.CPP3-0009-2018
• Rouchon CN, Ly AT, Noto JP, et. al. "Incremental Contributions of FbaA and Other Impetigo-Associated Surface Proteins to Fitness and Virulence of a Classical Group A Streptococcal Skin Strain." Infection and immunity, 85(11), (2017) . doi: 10.1128/IAI.00374-17
• Ly AT, Noto JP, Walwyn OL, et. al. "Differences in SpeB protease activity among group A streptococci associated with superficial, invasive, and autoimmune disease." PloS one, 12(5), (2017) e0177784. doi: 10.1371/journal.pone.0177784
• Ferretti JJ, Stevens DL, Fischetti VA, et. al. "Molecular Basis of Serotyping and the Underlying Genetic Organization of Streptococcus pyogenes." , (), (2016) .

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Memberships and Affiliations

• Associate Editor, PLoS Pathogens
• Curator, www.pubmlst.org/spyogenes, Hosted by University of Oxford, U.K.
• Member, Admissions Committee (M.D.), NYMC

Teaching Responsibilities

• Medical Microbiology (School of Medicine, NYMC)
• General Microbiology II (GSBMS, NYMC)
• Microbiology and Immunology (Touro College of Dental Medicine at NYMC)
• Infectious Diseases (New York College of Podiatry Medicine, Touro)