Title: A Comprehensive Literature Review on the Impact of Scardovia Wiggsiae on Cariogenic Dental Caries
Authors: Elena A. Munroe, OMS1; Myshelle M. Williams, OMS1; Kristen E. Senior, OMS1; Jen Reinmuth-Birch, OMS1
Introduction
Dental caries is a common yet detrimental oral health condition that is estimated to affect the permanent teeth of 2.3 billion people and the primary teeth of 530 million children worldwide. Dental caries result in the gradual loss of calcified tissues of the teeth, and in its advanced stages, can lead to pain, tooth loss, and severe infection. Scardovia wiggsiae, a novel gram-negative, biofilm-producing, bacillus member of the Actinomyces/Bifidobacterium family, has been found in cariogenic oral microbiomes.
Methods
A total of 37 peer-reviewed papers referencing S. wiggsiae were found on NCBI PubMed and Medline, including three review papers on the microbiomes associated with dental caries. The information pertaining to S. wiggsiae was then compiled and summarized.
Results
- wiggsiae has been found to be associated with severe early childhood caries, with elevations present in patients with fixed orthodontic appliances, elevated sugar intake, and patients with chronic kidney disease on dialysis. Using scanning electron microscopy, S. wiggsiae arranges in clusters within a rich biofilm matrix containing a micro-canalicular system used for protection, nutrient exchange, and communication. Advanced caries and lesion induction is associated with dual infection of S. wiggsiae and Streptococcus mutans. Compared to other dental caries-associated bacteria, S. wiggsiae has a higher acid production, lower enolase sensitivity, and can withstand oral cavities with a low pH. A study has shown that S. wiggsiae possesses a unique metabolic pathway, the F6PPK shunt, which may contribute to its fluoride and acid tolerance. The herbal extracts Anzer thyme, Stevia rebaudiana, and chlorhexidine were also found to be effective against S. wiggsiae.
Discussion
To successfully treat dental caries, it is imperative to first isolate and understand cariogenic microbes from the oral cavity. In children and adolescents, S. wiggsiae has been isolated from decaying tooth lesions as a primary cariogenic bacterium. A study has demonstrated that saliva collection provides an improved model to detect caries-affected from caries-free individuals, as compared to tooth biofilm samples. A promising option for the isolation of cariogenic bacteria from a limited plaque sample is the use of a dry-reagent biosensor-PCR-dipstick using DNA chromatography. This multi-taxonomic assay approach will allow for the monitoring and customization of community-level therapies, including the implementation of therapeutics to combat the unique metabolic behavior of S. wiggsiae. Additionally, further research into the introduction of microbiome modifying materials integrated into dental procedures may contribute to the implementation of pathogenic microbe inhibition techniques into standard dental practices.
Thanks for the interesting presentation. As a judge for this project, I was wondering what percentage of dental caries and/or dental biofilms contain this organism and if there are other places besides these dental biofilms where this bacterium lives.
Thank you for the question Dr. Rhodes. As this is a relatively newly discovered bacteria, obtaining accurate prevalence numbers is still an ongoing pursuit. Several studies have reported varying percentages of the S. wiggsiae bacterium present in the dental microbiome, the differences being largely dependent on the population sampled and the degree of advancement of dental caries present. It has been found, that the more progressive the dental caries burden is, the greater the percentage of S. wiggsiae is present. Prevalence between the severity of dental caries and the different bacteria found is also shown on slide 5 of the presentation.
A study on oral site-specific analysis was done in 2021 and did provide some of the first evidence to suggest this organism may be present not only in traditional supragingival tooth-associated biofilm sites but also in non-traditional oral sites including the dorsum of the tongue and the gingival crevice. However, with only the relatively recent discovery of this organism, no studies outside the oral cavity have been published (McDaniel S, et al., 2021). This would be an interesting avenue to pursue for future research.
McDaniel S, McDaniel J, Howard KM, Kingsley K. Molecular Screening and Analysis Reveal Novel Oral Site-Specific Locations for the Cariogenic Pathogen Scardovia wiggsiae. Dent J (Basel). 2021 Jun 17;9(6):73. doi: 10.3390/dj9060073. PMID: 34204219; PMCID: PMC8234915.
Nice review and presentation. We know that microbiomes are very complex microenvironments. Was there any literature on a bacteria that might outcompete or decrease the levels of S. wiggsiae? Or any targeted antimicrobials?
Thanks for the interesting presentation, Student Dr. Munroe. I have been assigned to be a judge for this project. On the poster, you mentioned looking at specific populations. Did you sort your 37 articles based on populations studied? If so, what was the most commonly reported population? If not, how come? Thanks so much.
Thank you for the question Dr. Briggs Early. Due to the low number of total articles found, we did not sort them by population, a method that would have been favorable. However it was found frequently throughout our search, that children of lower socioeconomic populations tended to have higher incidences of the bacterium. While a few of the articles did obtain samples for study from both children and adults, one of which focused on patients with chronic kidney disease on hemodialysis (Yue, et al., 2018). Research thus far has mainly been with children, likely in an effort to understand and hinder the induction of dental caries prior to infection of the permanent dentition. The number of studies directed towards the oral microbiome of children could be due to a number of reasons, including the increased rate of dental visits in childhood, the impact of low socioeconomic effects, second hand nicotine exposure, and an attempt to avoid poor oral health education. Additional research into the presence of S. wiggsiae in adult populations, as well as the specific populations of children being affected by dental caries would be compelling avenues for further research.
Yue Q, Yin FT, Zhang Q, Yuan C, Ye MY, Wang XL, Li JJ, Gan YH. Carious status and supragingival plaque microbiota in hemodialysis patients. PLoS One. 2018 Oct 9;13(10):e0204674. doi: 10.1371/journal.pone.0204674. PMID: 30300382; PMCID: PMC6177147.
Thanks for your thorough response, Student Dr. Munroe!
Thank you for the question Dr. Habecker. As you mentioned, the oral microbiome is incredibly complex and varies among ages, populations, and numerous other factors. From the 37 articles that were available at the time of our review, some studies recommended finding a long-term balance in the dysbiosis of S. wiggsiae and other microbes, rather than eliminating the bacterium completely (Zhan L., 2018).
Another proposed treatment modality that shows promise is the implementation of interventions in the cariogenic processes. This could potentially include the use of sugar substitutes xylitol and erythritol to interrupt typical cariogenic processes with the intention of shifting the oral microbiome to a state less supportive of dental caries, an exciting proposition for future research (Zhan L., 2018). Further, another proposed treatment modality focused on viral-mediated gene delivery may also help in reducing S. wiggsiae and related biofilms formed by the bacterial burden in the oral cavity (Fernandes, et al., 2018). Additionally, the herbal extracts Anzer thyme, Stevia rebaudiana, and chlorhexidine were also found to be effective against S. wiggsiae and may have space for future investigation (Demirez, et al., 2021).
Fernandes, T, Bhavsar, C, Sawakar, S & D’souza, A (2018). Current and novel approaches for control of dental biofilm. Pharmaceutics, 536(1): 199-201.
Demirez Bircan Z, Aydinoglu S, Arslan I, Alpay Karaoglu S, Yurteri E, Bozdeveci A. Comparative evaluation of various herbal extracts on biofilms of Streptococcus mutans and Scardovia wiggsiae: An in vitro study. Int J Paediatr Dent. 2021 Sep 26. doi: 10.1111/ipd.12929. Epub ahead of print. PMID: 34564912.
Zhan L. Rebalancing the Caries Microbiome Dysbiosis: Targeted Treatment and Sugar Alcohols. Adv Dent Res. 2018 Feb;29(1):110-116. doi: 10.1177/0022034517736498. PMID: 29355418; PMCID: PMC5784483