| PubMed ID | Author / Year | Patient Group | Study type (level of evidence) |
| 28134351 | Dongyeop/2017 | Bacterial and fungal biofilms | Laboratory study |
| Key results | Conditioned medium was gathered from single-species bacterial S. mutans, single-species fungal C. albicans, or a mix of bacterial-fungal biofilms spaced out at certain time-points: 6, 18 and 30 hours. These time periods correlate to active biofilm growth. “The results showed that BF-CM [bacterial and fungal conditioned media] collected at 18 h significantly promoted bacterial accumulation within biofilms compared to control (no supplementation, P < 0.001). In contrast, no significant increase in the bacterial cell population was detected when S. mutans was grown in CM preparations from single-species biofilms or from BF-CM at other time-points. It appears that during the initial phase of active biofilm formation (between 6 h to 18 h) the presence of cross-kingdom metabolites could be enhancing S. mutans cell growth, while at the later time point (30 h) this effect is attenuated possibly due to reduced microbial/metabolic activity. Thus, hereafter further experiments were focused on the bioactivity of BF-CM collected at 18 h on biofilm formation by S. mutans. Using different dilutions of BF-CM, the data showed a clear trend of increasing number of viable S. mutans-biofilm cells (>6-fold increase at highest BF-CM content vs. no supplementation) in a dose-dependent manner (r2 = 0.9) suggesting that BF-CM contains bacterial growth-inducing factors.” This experiment allows us to study the “chemical interactions between an opportunistic fungus and an oral pathogen, which in part help to explain the in vivo and clinical findings showing enhanced S. mutans carriage in the presence of C. albicans in plaque-biofilms associated with [early childhood caries].” One of the main modulators in this cross-kingdom biofilm is farnesol. At high concentrations, farnesol has been found to decrease the growth of both S. mutans and C. albicans. As a result, this can lessen the pathogenicity of the biofilm created by these two organisms. This shows that there is a possibility of utilizing an anti-fungal therapy approach in treating children with early childhood caries in the future. | ||
| 24566629 | Falsetta/2014 | Six litters of 8 female Sprague Dawley rats aged 15 days. 4 groups: (1.) S. mutans infected, (2.) C. albicans infected, (3.) S. mutans plus C. albicans infected, and (4.) uninfected. | Randomized Controlled Trial |
| Key results | Six litters of 8 female Sprague Dawley rats were (1) S. mutans infected, (2) C. albicans infected, (3) S. mutans plus C. albicans infected, or (4) uninfected. The researchers evaluated the formation of a biofilm for each of the groups listed. “The jaws were aseptically dissected and were processed for microbiological analysis of each animal's plaque biofilms …”. They examined the EPS (extracellular matrix of polymeric substances)-mediated bacterium-fungus interaction when sucrose was present. It was found that the EPS-mediated matrix biofilm was denser and greater in size when both C. albicans and S. mutans were present, compared to just a single organism being present. The researchers measured different times in the group of rats that were infected with both organisms. It was found that by 8 hours of post infection, the first signs of C. albicans were detected. S. mutans was already present by 6 hours. After 42 hours, great amounts of fungal cells were present. “Furthermore, cospecies biofilms displayed more (at the early stage of 18 h) and larger (at 42 h) microcolonies than S. mutans-only biofilms (P, <0.05).” The significance of this study is that a biofilm becomes more virulent in time in animals. Since farnesol was used to reduce the pathogenicity of a cross-kingdom biofilm, this metabolite can potentially be used to reduce the pathogenicity in the jaws of Sprague Dawley rats. Most importantly, farnesol could possibly be used as an antifungal agent to decrease the prevalence of Streptococcus Mutans in a biofilm. | ||
The Evidence
| Basic Science Rationale (Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?) |
| None available |
| Comments and Evidence-Based Updates on the CAT (FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs) |
| None available |