Identification of Non- Streptococcus mutans Bacteria from Predente Infant Saliva Grown on Mitis-Salivarius-Bacitracin Agar

Comparison the salivary streptococcus mutans levels between caries-active and caries-free children from Birjand, Iran: A case-control study

Objective

Dental plaque bacteria, including Streptococcus mutans (SM), play a role in the pathogenesis of the dental caries. There are conflicting results regarding the association of salivary SM level and dental caries susceptibility. Our aim was to compare salivary SM levels in colony-forming units (CFU) between children with active caries and caries-free children in Birjand, Iran.

Methods

This case-control study included 61 six-year-old children referred to health centers in Birjand city, Iran, in 2022. The children were divided into two groups: case (dmft/DMFT>0 with active caries) (including 31 children) and control (dmft/DMFT = 0 [caries-free]) (including 30 children). Demographic information and dental history were recorded. Oral examinations were also performed by the dentist. Unstimulated saliva samples were collected from children. The number of salivary SM colonies was determined using the microbial culture and confirmed using the polymerase chain reaction (PCR). The data were analyzed using Chi-square and T-tests at a significance level of p < 0.05.

Results

The mean number of SM colonies was 126.24 ± 92.78 CFU/ml and 92.38 ± 75.34 CFU/ml in case and control groups, respectively. No significant difference was found in salivary SM levels between case and control groups (P = 0.125). No significant association was observed between caries experience with gender (P = 0.363), type of school (public/private) (P = 0.296), receiving oral health education (P = 0.072) and frequency of tooth brushing (P = 0.935). The mean gingival index (P = 0.001) and plaque index (P = 0.025) in case group were significantly higher than control group.

Conclusion

There is no significant difference in salivary SM levels between caries-active and caries-free children in Birjandi children.

Isolation and detection of bacterial species on mitis salivarius bacitracin agar from the plaque samples of caries active children

BACKGROUND

In cariology studies, mitis-salivarius-bacitracin (MSB) agar has been commonly considered as the selective medium for Streptococcusmutans growth. The present study was the part of a funded project (a noninferiority randomized controlled trial) which compared the efficacy of a plant extract-based mouth rinse with that of a fluoride mouth rinse on the S.mutans counts of the children.

AIM

This study aimed to identify the frequency of detection of S.mutans and nonstreptococcal bacterial species from the dental plaque of caries active children using a combined technique of anaerobic culture and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry.

SETTINGS AND METHODS

Caries-active children (8-12 years old) were enrolled from a pediatric dental outpatient department at a tertiary care hospital. From each participant, dental plaque samples were collected from carious surfaces under sterilized conditions and then subjected to anaerobic culture. After 48 h of incubation, the bacterial colonies were isolated by sub-culture and identified by the MALDI-TOF.

RESULTS

In all, 13 different bacterial species were isolated from the MSB agar medium. Other than S.mutans species, colonies of bacterial species such as Veillonelladispar,Streptococcusanginosus, Veillonellaparvula, and Streptococcusgordonii were also frequently observed from the medium.

CONCLUSIONS

The study concluded that several bacterial strains, both streptococcal and nonstreptococcal, could be isolated from the MSB agar medium; hence, this medium should no longer be considered selective medium for the culture of S.mutans in clinical and epidemiological studies.

Effects of Nystatin oral rinse on oral Candida species and Streptococcus mutans among healthy adults

OBJECTIVES

To examine the effect of Nystatin oral rinse on oral Candida species and Streptococcus mutans carriage.

MATERIALS AND METHODS

Twenty healthy adults with oral candidiasis participated in the single-arm clinical trial and received Nystatin oral rinse for 7 days, 4 applications/day, and 600,000 International Units/application. Demographic-socioeconomic-oral-medical conditions were obtained. Salivary and plaque Candida species and Streptococcus mutans were assessed at baseline and 1-week and 3-month follow-ups. Twenty-four salivary cytokines were assessed. Candida albicans isolates underwent Nystatin susceptibility test.

RESULTS

Half of participants (10/20) were free of salivary C. albicans after using Nystatin rinse. Salivary S. mutans was significantly reduced at 3-month follow-up (p < 0.05). Periodontal status reflected by bleeding-on-probing was significantly improved at 1-week and 3-month follow-ups (p < 0.05). Plaque accumulation was significantly reduced at 1-week follow-up (p < 0.05). Interestingly, the responses to Nystatin oral rinse were not associated with race, gender, age, oral hygiene practice, adherence to Nystatin rinse, or sweet consumption (p > 0.05). No C. albicans isolates were resistant to Nystatin. Furthermore, salivary cytokine eotaxin and fractalkine were significantly reduced at 3-month follow-up among participants who responded to Nystatin rinse (p < 0.05).

CONCLUSIONS

The study results indicate that oral antifungal treatment had an effect on S. mutans salivary carriage. Future clinical trials are warranted to comprehensively assess the impact of antifungal treatment on the oral flora other than S. mutans and Candida.

CLINICAL RELEVANCE

Due to the potential cariogenic role of oral Candida species, antifungal approaches shed new light on the prevention and management of dental caries from a fungal perspective.

Comparative evaluation of antibacterial efficacy of active oxygen containing versus other dentifrices against Streptococcus mutans count in children with early childhood caries: A clinico-microbiological study

Background

Fluoridated dentifrices have been used for the prevention of dental caries since ages. However, to avoid the risk of fluorosis, the use of newer nonfluoridated options in dentifrices has shown a great interest in reducing Streptococcus mutans (SM) in early childhood caries (ECC).

Aim

The study aimed to evaluate the antimicrobial efficacy of active oxygen (AO)-based dentifrice with amine fluoride (AF)-, sodium monofluorophosphate (SMP)-, herbal (HB)-, and tricalcium phosphate (TCP)-based dentifrices on SM count in children with ECC.

Materials and Methods

Two hundred and fifty children aged 3-6 years with def ≥4 were selected and randomly divided into five groups of 50 each, based on the type of dentifrices used; Group I: AO-based, Group II: TCP, Group III: SMP, Group IV: AF, and Group V: HB dentifrice, and were asked to brush twice daily for 15 days. The saliva samples were collected at baseline, and after 15 days, cultured for SM colonies count.

Results

Difference in colony-forming units (CFU)/ml between baseline and 15 days was highly significant in all the five groups (P < 0.001). Significant difference was observed in SM count after 15 days between Groups I and IV (P = 0.017), while nonsignificant differences were seen when compared with Groups II, III, and V (P = 0.975, 0.137, and 0.992).

Conclusions

All the dentifrices were efficacious in reducing SM count in children with ECC. Although AO dentifrice showed superior results when compared to SMP, TCP, and HB, it did not prove to be superior to AF.

Saliva sampling methods. Cariogenic streptococci count using two different methods of saliva collection in children

The aim of this study is to compare the efficacy of two methods for collecting saliva samples from infants under 2 years of age for cariogenic streptococci (CS) count. Two collection methods were applied in 11 infants. In Method (A), saliva samples were collected by swabbing the inner cheek mucosa and floor of the mouth in figure of eight motions with a sterile cotton swab until it was soaked. In method (B), saliva samples were collected by aspiration of 1 ml of saliva with a sterile plastic syringe on the floor of the mouth, after stimulation with glove. The samples were cultured in modified Gold's broth (MSMG), and on trypticase, yeast extract, sucrose, cystine and bacitracin culture medium (TYSCB). In method (A), the swab with the sample was unloaded in situ on TYSCB and placed in PBS medium for transport. Then, 100 μl of the eluate was seeded in MSMG. In method (B) 100 μl were seeded in TYSCB and 100 μl in MSMG. Both culture media were incubatedundercapnophilicconditions for 48 hours at 37 °C. Colony forming units (CFU/ml) were counted by calibrated operators (kappa = 0.75). The presence of cariogenic streptococci (CS) (Streptococcus mutans-Streptococcus sobrinus) was determined by qPCR in the samples collected by both methods. The CFU/ml counts in MSMG differed significantly between methods (p = 0.021). In TYSCB, the recovery of CFU/ml was higher in method (A), without significant difference (p = 0.705). The molecular technique detected presence of CS, with no difference between collection methods. Collecting saliva samples by swabbing proved more effective in terms of recovery of microorganisms, and did not affect the detection of presence of CS by molecular techniques.

Oral Candida Predicts Streptococcus mutans Emergence in Underserved US Infants

Despite the cariogenic role of Candida suggested from recent studies, oral Candida acquisition in children at high risk for early childhood caries (ECC) and its association with cariogenic bacteria Streptococcus mutans remain unclear. Although ECC disproportionately afflicts socioeconomically disadvantaged and racial-minority children, microbiological studies focusing on the underserved group are scarce. Our prospective cohort study examined the oral colonization of Candida and S. mutans among 101 infants exclusively from a low-income and racial-minority background in the first year of life. The Cox hazard proportional model was fitted to assess factors associated with the time to event of the emergence of oral Candida and S. mutans. Oral Candida colonization started as early as 1 wk among 13% of infants, increased to 40% by 2 mo, escalated to 48% by 6 mo, and remained the same level until 12 mo. S. mutans in saliva was detected among 20% infants by 12 mo. The emergence of S. mutans by year 1 was 3.5 times higher (hazard ratio [HR], 3.5; confidence interval [CI], 1.1-11.3) in infants who had early colonization of oral Candida compared to those who were free of oral Candida (P = 0.04) and 3 times higher (HR, 3.0; CI, 1.3-6.9) among infants whose mother had more than 3 decayed teeth (P = 0.01), even after adjusting demographics, feeding, mother's education, and employment status. Infants' salivary S. mutans abundance was positively correlated with infants' Candida albicans (P < 0.01) and Candida krusei levels (P < 0.05). Infants' oral colonization of C. albicans was positively associated with mother's oral C. albicans carriage and education (P < 0.01) but negatively associated with mother's employment status (P = 0.01). Future studies are warranted to examine whether oral Candida modulates the oral bacterial community as a whole to become cariogenic during the onset and progression of ECC, which could lead to developing novel ECC predictive and preventive strategies from a fungal perspective.

Changes in Candida albicans, Streptococcus mutans and oral health conditions following Prenatal Total Oral Rehabilitation among underserved pregnant women

Objectives

To assess the oral health condition and oral microbial outcomes from receiving an innovative treatment regimen - Prenatal Total Oral Rehabilitation (PTOR).

Methods

This prospective cohort study included 15 pregnant women in the PTOR group who had a baseline visit before PTOR and three follow-up visits (immediate after, 2 weeks and 2 months) after receiving PTOR. A historical control group of additional 15 pregnant women was matched from a separate study based on a propensity score. Along with demographic and medical background, oral health conditions and perinatal oral health literacy were assessed. Oral samples (saliva and plaque) were analyzed to identify and quantify Streptococcus mutans and Candida species by culturing-dependent and -independent methods.

Results

Significant reductions of salivary S. mutans were observed following PTOR, the effect remained until 2-month follow-up (p < 0.05). The carriage of salivary and plaque S. mutans at the 2-month visit of the PTOR group was significantly lower than that of the control group (p < 0.05). Oral health conditions reflected by BOP and PI were significantly improved upon receiving PTOR (p < 0.05). Receiving PTOR significantly improved the perinatal oral health literacy score, and the knowledge retained until 2-month follow-up (p < 0.05).

Conclusions

PTOR is associated with an improvement in oral health conditions and perinatal oral health literacy, and a reduction in S. mutans carriage, within a 2-month follow-up period. Future clinical trials are warranted to comprehensively assess the impact of PTOR on the maternal oral flora other than S. mutans and Candida, birth outcomes, and their offspring's oral health.

Isolation and Identification of Potentially Pathogenic Microorganisms Associated with Dental Caries in Human Teeth Biofilms

Dental caries is attributed to the predominance of cariogenic microorganisms. Cariogenic microorganisms are pathological factors leading to acidification of the oral microenvironment, which is related to the initiation and progression of caries. The accepted cariogenic microorganism is Streptococcus mutans (S. mutans). However, studies have found that caries could occur in the absence of S. mutans. This study aimed to assess the presence of potentially cariogenic microorganisms in human teeth biofilm. The microorganisms were isolated from human mouth and freshly extracted human maxillary incisors extracted for reasons of caries. The isolates were sorted based on their acidogenic and aciduric properties, and the S. mutans was used as the reference strain. Four potentially cariogenic strains were selected. The selected strains were identified as Streptococcus salivarius (S. salivarius), Streptococcus anginosus (S. anginosus), Leuconostoc mesenteroides (L. mesenteroides), and Lactobacillus sakei (L. sakei) through morphological analysis followed by 16S rRNA gene sequence analysis. The cariogenicity of isolates was analyzed. We show, for the first time, an association between L. sakei (present in fermented food) and dental caries. The data provide useful information on the role of lactic acid bacteria from fermented foods and oral commensal streptococci in dental caries.