Thesis
Evaluating the ability of marketed oral probiotics to interfere with the growth of clinical strains of Streptococcus mutans
University of Iowa
Master of Science (MS), University of Iowa
Spring 2021
DOI: 10.17077/etd.005922
Abstract
Objective: To isolate probiotic strains from commercially available oral probiotics and examine each probiotic strain’s ability to inhibit the growth of representative strains of cariogenic species and species associated with a healthy oral environment.Materials & Methods: Bacterial strains, representing a diverse taxonomical panel, were isolated from commercially available oral probiotic products based on a Gram stain and/or polymerase chain reaction with species or strain-specific primers.
Growth antagonisms were assayed by standardizing inoculums to an optical density (OD600) of 0.100 ± 0.005. Seven microliters of the probiotic strain were inoculated onto a blood agar plate and incubated overnight. Next, a suspension of identical OD was made with the test strain and 7ul was inoculated adjacent to the probiotic strain and incubated a second night. The order of plating was reversed to determine possible inhibition of the probiotic strain by the challenge strains. Areas of inhibition were calculated as percentages.
Results: Nine probiotic strains were isolated from commercial products: 5 Streptococcus, 3 Lactobacillus and 1 Bifidobacterium. Only Streptococcus strains had growth inhibitory activity with 3 strains displaying varying percentages of growth inhibition against members of the mutans streptococci. One of those, Streptococcus rattus JH145, inhibited all 4 clinical isolates of S. mutans. An equivalent number of strains (3 of 9 probiotic strains) showed inhibition toward health-related oral species. Only Streptococcus oralis K13 exclusively inhibited S. mutans. No growth inhibition was seen towards any of the isolated probiotic strains from the challenge bacteria.
Conclusion: There remains uncertainty regarding the mechanisms by which probiotic regimens may benefit oral health. Selective growth inhibition of oral pathogens is considered a desirable characteristic for probiotic strains. The results of this study suggest that only a small subset of marketed probiotics possess this property.
Details
- Title: Subtitle
- Evaluating the ability of marketed oral probiotics to interfere with the growth of clinical strains of Streptococcus mutans
- Creators
- Mohammadhossein Tajik
- Contributors
- Jeffrey A Banas (Advisor)Kyungsup Shin (Advisor)Steven R Armstrong (Committee Member)Justine L Kolker (Committee Member)Xian Jin Xie (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Oral Science
- Date degree season
- Spring 2021
- DOI
- 10.17077/etd.005922
- Publisher
- University of Iowa
- Number of pages
- vii, 48 pages
- Copyright
- Copyright 2021 Mohammadhossein Tajik
- Language
- English
- Description bibliographic
- Includes bibliographical references (pages 44-48)
- Public Abstract (ETD)
Dental caries is a result of acid production by some oral bacteria which dissolves the tooth structure. Multiple measures are utilized to prevent dental decay. However, most people still need restorations due to dental caries. Probiotics are microorganism that have potential in reduction/inhibition of bacteria responsible for tooth decay. The use of probiotics for oral health does not have a long history but several products are nonetheless marketed for oral health without strong evidence of clinical efficacy.
Lab studies have shown the reduction of mutans streptococci (major contributors to dental decay) is one of the effects of selected probiotic regimens. Only a few clinical trials have studied the effects of probiotic therapy on reducing dental caries, but these studies have revealed a potential benefit. Probiotics hold promise as a preventive measure in oral health; however, more research is needed to understand the effects of probiotics on caries before we can inform clinical practice. If proven useful, probiotics provide an easy and low-cost option for patients to improve their oral health and possibly prevent the need for restorative treatment.
Thus, the aim of this project was to evaluate some of the probiotic products marketed as oral probiotics and see if they have any effects against Streptococcus mutans which is known to be one of the main species responsible for tooth decay. The second aim of the project was to evaluate the possible effects of the probiotics on some of the health-related bacteria such as Streptococcus sanguinis and Streptococcus gordonii.
- Academic Unit
- Oral Pathology, Radiology and Medicine
- Record Identifier
- 9984096974602771
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