Dr. Weimer's laboratory group focuses on microbial physiology and function. Research on host/microbe interactions has led to the elucidation of the competitive binding of beneficial bacteria to the gut epithelium and the resulting displacement of pathogenic bacteria such as salmonella. Using genomics and functional genomics — gene expression, metabolomics, proteomics, and metagenomics — Dr. Weimer's program examines the mechanisms of gene interplay to produce a specific phenotype and the metabolism involved in the process. The interplay between the host, the microbe, and the interdependent response is a key question for his program. The primary thrust of his program is the systems biology of biological processes important for bacterial growth, survival, and persistence.

Recent work has focused on the specifics of bacterial adhesion in the gut. By using the Caco 2 cell model, Dr. Weimer has explored the binding of specific bacterial strains, the competitive binding of beneficial and pathogenic bacteria, the discovery of the molecular mechanisms of adhesion, and the cellular signaling that takes place when bacteria adhere to the intestinal wall. In addition, the group has investigated the adhesion and competitive binding of bacteria grown on human milk oligosaccharides compared with lactose. The findings of this research will pave the way toward understanding the underlying mechanisms of the benefits of “good bacteria” and how they modulate host immunity.