Influence of Cell Wall Polysaccharides on Structure and Mechanics of Streptococcus mutans

Streptococcus mutans (S. mutans) is a group of cocci bacteria that highly contributes to oral decay. In cases of high potency, it can cause plaque build-up, impaired speech, difficulty chewing, and cavity formation, which contribute to over half of the dental visits in the United States. In severe cases where a biofilm develops on a dental implant, patients will experience pain, swelling, and potential loosening or loss of the titanium implant. S. mutans are also highly resistant to antibiotics, which makes the infections both persistent and difficult to treat. As poor oral hygiene continues to be a global epidemic, it is important to study and characterize the mechanics of the bacteria to develop therapeutic targets to alleviate S. mutans infections. One possible target is modifications of the cell wall. Recent literature suggests that alterations to the biosynthesis pathways of cell wall polysaccharides could lead to new opportunities for therapeutics. The cell wall of S. mutans is high-functioning and complex. It consists of multiple peptidoglycan layers, wall teichoic acid (WTA) containing surface glycopolymers, and a polysaccharide capsule. Using atomic force microscopy (AFM) in combination with fluorescent laser scanning confocal imaging, we compare cell wall deformation with mutants defective in WTA. Furthermore, scanning electron microscopy of both wild type S. mutans and mutant strains reveal differences in surface morphology. Our long-term goal is to determine mechanical and structural properties of bacterial cell walls that contribute to antibiotic resistance in order to preferentially regulate such properties.