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Wednesday Afternoon Lecture Series (WALS) - Microbiota-mediated defense against antibiotic-resistant infections

January 10, 2018

3:00pm - 4:00pm

Building 10, Clinical Center, Masur Auditorium

The NIH Director's Wednesday Afternoon Lecture Series, colloquially known as WALS, is the highest-profile lecture program at the NIH. Lectures occur on most Wednesdays from September through June from 3:00 to 4:00 p.m. in Masur Auditorium, Building 10 on the NIH Bethesda campus.

Each season includes some of the biggest names in biomedical and behavioral research. The goal of the WALS is to keep NIH researchers abreast of the latest and most important research in the United States and beyond. An added treat is the annual J. Edward Rall Cultural Lecture, which features top authors and other cultural icons. All speakers are nominated by the NIH community.

The full WALS lecture season agenda is available at


Eric Pamer, M.D.
Director, MSK Center for Microbes, Inflammation and Cancer
Memorial Sloan Kettering Cancer Center

Lecture summary:
Infections caused by antibiotic-resistant bacteria generally begin with colonization of mucosal surfaces, in particular the intestinal epithelium. The intestinal microbiota provides resistance to infection with highly antibiotic-resistant bacteria, including Vancomycin Resistant Enterococcus faecium (VRE), Klebsiella pneumoniae and Clostridium difficile, the major cause of hospitalization-associated diarrhea. Metagenomic sequencing of the murine and human microbiota following treatment with different antibiotics is beginning to identify bacterial taxa that are associated with resistance to VRE and C. difficile infection. By treating mice with different antibiotics that result in distinct microbiota changes and lead to varied susceptibility to C. difficile, we correlated loss of specific bacterial taxa with development of infection. Using a workflow involving mouse models, clinical studies, metagenomic analyses and mathematical modeling, we identified a probiotic candidate that corrects the microbiome deficiency responsible for susceptibility to C. difficile infection. Using a similar strategy, we demonstrated that oxygen-tolerant members of the microbiota are ineffective at eliminating VRE while administration of obligate anaerobic commensal bacteria to mice results in a billion-fold reduction in the density of intestinal VRE colonization. We have identified specific bacterial species, including Blautia producta and Clostridium bolteae, which prevent intestinal colonization with VRE and lead to its clearance from the gut. Our studies indicate that obligate anaerobic bacteria that can be retrieved from the commensal microbiota enable clearance of intestinal VRE colonization and provide resistance to C. difficile infection. These bacterial species may provide novel approaches to prevent the spread of highly antibiotic-resistant bacteria.

This lecture will be followed by a reception in the NIH Library. Special thanks to the Foundation for Advanced Education in the Sciences (FAES) for its support of the weekly reception. FAES is proud to co-sponsor with the NIH in hosting the Wednesday Afternoon Lecture Series.

To watch the lecture online, visit Registration is not required; seating is on a first-come, first-served basis. Fire regulations require that every person in Masur Auditorium must have a seat. Standing in the aisles or in the back of the auditorium is not permitted. Sign language interpreters can be provided. Individuals with disabilities who need reasonable accommodation to participate in this event should contact Jacqueline Roberts,, 301-594-6747, or the Federal Relay, 800-877-8339.