Bacterial Cell Wall Glycopolymers Affect Polymer Chain Alignment and Mechanics of Streptococcus mutans

Antibiotic resistance is the phenomenon in which bacteria is or becomes resistant to antibiotics. As it pertains to oral bacteria, current methods for elimination of their presence and reduction of infection is through mechanical means, such as brushing, flossing, or swishing with an alcoholic rinse. These methods loosen the bacteria from oral surfaces or attack bacteria through cell disruption by protein denaturation and lipid membrane dissolution. One strain of oral bacteria that can cause plaque accumulation, chewing difficulty, impaired speech, and dental caries is Streptococcus mutans (S. mutans). S. mutans is a group of Gram-positive, facultatively anaerobic, cocci bacteria that can contribute to a multitude of oral hygiene concerns, including loss of dental implants in cases of high concentration. Research suggests that modification of the cell wall may lead to new developments on how to regulate cell permeation, thereby, regulation of microbial resistance mechanisms. In this work, three S. mutans stains with altered peptidoglycan layers are studied through atomic force and confocal microscopy. Surface roughness differences due to molecular glycerol phosphate alterations are quantified and compared at two positions: near the pole of the cell and within the septal region. We show AFM images of bacteria scans, including the cell wall, and quantitative surface roughness measurements at the two difference regions for each strain investigated.