Scientists at the University of Pennsylvania School of Dental Medicine made an unexpected discovery while studying saliva samples from children with severe forms of tooth decay. They discovered that oral bacteria can combine with fungi to create a type of organism that moves through teeth at incredible speeds, promoting tooth decay.
A research team from the University of Pennsylvania found that within a few hours of growth, groups of bacteria were able to “jump” more than 200 times their body length across the surface of teeth, providing an accurate explanation for the mechanism behind rapid bacterial colonization and dental caries.
In a university press release, study co-author Professor Heng Michel Koo, founding director of the university's Center for Innovation and Precision Dentistry, said that although the organisms making up the biofilm were nonmotile, the combination they have formed a “superorganism”: a clump that is much more difficult to remove from teeth than either of its two components individually.
When the research team studied severe childhood tooth decay in toddlers, they were shocked to discover that the mixture of bacteria and fungi actually developed the ability to “walk” and “jump.” The organisms in question, Streptococcus mutans and the fungus Candida albicans, have been identified as the main components of the biofilm causing severe dental caries in children.
Dr. Zhi Ren, a graduate student working in the lab and one of the study's co-authors, used a form of microscopy that allowed the team to observe changes in organisms in real time. Bacteria and fungi have been able to develop unexpected levels of adhesion and microbial tolerance. The fungi sprouted hyphae, which allowed the bacteria to better attach and resist removal. The colonies firmly “stuck” to the teeth and coped well with the attacks of antimicrobial drugs.
Despite the secure attachment, the new superorganism can not only “move its legs, but also jump from tooth to tooth like bacteria hitchhiking on mushrooms,” said Professor Ku. This ability meant that once clumps were tested on human teeth in a laboratory model, the biofilm spread much faster than expected because the organisms were able to move as they grew
The findings may not only help dentists better understand the levels of prevention needed to prevent them. severe caries, but can also help clinicians understand the spread of bacteria in other areas of medicine.
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