Comparative Evaluation of Antibacterial and Anti-Adherent Properties between Titanium Oxide, Silver Dioxide-Coated, and Conventional Orthodontic Wires Against Streptococcus Sanguis Causing Gingivitis

Objective

To compare the antibacterial and anti-adherent properties of conventional stainless steel (SS) orthodontic wires and surface-modified silver dioxide-coated and titanium oxide-coated SS orthodontic wires against Streptococcus sanguis causing gingivitis.

Materials and Methods

The study used 60 orthodontic SS wire specimens, organized into six groups of ten each. The control group had uncoated wires, and the experimental group featured wires coated with silver dioxide and titanium oxide. Surface modification was done using DC sputtering, and microbiological tests assessed the antibacterial and anti-adherent properties of the AgO2- and TiO2-coated wires.

Results

This study demonstrated the antibacterial effect against S. sanguis in orthodontic wires coated with the photocatalytic AgO2 and TiO2 compared to the uncoated wires. Also, this study demonstrated an anti-adherent effect in the AgO2- and TiO2-coated orthodontic wires. Moreover, the bacterial accumulation on orthodontic wires coated with AgO2 and TiO2 was lower compared to that on the uncoated wires.

Conclusion

During orthodontic treatment, the formation of dental plaque can be prevented by coating the surface of stainless-steel orthodontic wires with photocatalytic AgO2 and TiO2. Compared to silver dioxide, the titanium oxide-coated SS orthodontic wires showed better antibacterial and anti-adherent properties.

Antibacterial effects of aqueous and alcoholic extracts of Zataria multiflora in comparison with chlorhexidine mouthwash on some pathogenic oral streptococci: An in vitro study

Background

Increasing antibiotic resistance to pathogenic microorganisms (Streptococci) has led scientists around the world to turn to medicinal plants. In this study, the effects of aqueous and alcoholic extracts of Zataria multiflora on the in vitro growth of Streptococcus mutans and Streptococcus sanguis have been considered and compared with 0.2% chlorhexidine mouthwash.

Materials and Methods

In this in vitro study, the inhibitory growth zone was accessed by the disc diffusion method after 48 h of incubation at 37 C. To find out the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of treatments, colony counts of cultured bacteria on nutrient agar have been considered at serial dilution at 1/2-1/1024 dilution rates. An independent t-test was used to compare the antibacterial effects of extracts while the level of significance of was considered to be 5% (P < 0.05).

Results

The inhibitory growth zones of aqueous and alcoholic extracts on S. mutans were 26.8 mm and 35.8 mm, respectively, whereas growth zones for S. sanguis were considered as 25.8 mm and 33.2 mm, sequentially. Comparisons showed better effects of alcohol compared to aqueous extract (P > 0.05). The MIC and MBC assessments showed the same results (P > 0.05). In all comparisons, the effects of 0.2% chlorhexidine mouthwash were significantly better than both Z. multiflora aqueous and alcoholic extracts (P > 0.05).

Conclusion

The different solvents may have contributed to the better effects of an alcoholic to aqueous extract of Z. multiflora on the growth of both bacteria. These two extracts could be used for early inhibition of the growth of the planktonic phase, as well as for better oral taste after chlorhexidine applications.

Antimicrobial photodynamic therapy mediated by methylene blue coupled to β-cyclodextrin reduces early colonizing microorganisms from the oral biofilm

OBJECTIVE

To test the effect of antimicrobial photodynamic therapy (A-PDT) on the oral biofilm formed with early colonizing microorganisms, using the photosensitizer methylene blue coupled with β-cyclodextrin nanoparticles and red light sources laser or LED (λ =660 nm).

METHODS

The groups were divided into (n = 3, in triplicate): C (negative control, 0.9 % NaCl), CX (positive control, 0.2 % chlorhexidine), P (Photosensitizer/Nanoparticle), L (Laser), LED (light-emitting diode), LP (Laser + Photosensitizer/Nanoparticle) and LEDP (LED + Photosensitizer/Nanoparticle). A multispecies biofilm composed ofS. gordonii, S. oralis, S. mitis, and S. sanguinis was grown in microplates containing BHI supplemented with 1% sucrose (w/v) for 24 h. Light irradiations were applied with a laser at 9 J for 90 s (320 J/cm²), or with LED, at 8.1 J for 90 s (8.1 J/cm²). The microbial reduction was assessed by counting viable biofilm microorganisms in selective culture media, before and after the treatments. Data normality was assessed by the Shapiro-Wilk test, and the results were submitted to Kruskal-Wallis analysis, followed by Dunn's test, with a significance level of 5%.

RESULTS

The groups LP and LEDP were able to significantly reduce the biofilm microorganism counts by as much as 4 log₁₀ times compared to the negative control group (p < 0.05) and did not statistically differ from the positive control group (CX) (p > 0.05).

CONCLUSION

The A-PDT mediated by encapsulated β-cyclodextrin methylene blue irradiated by Laser or LED was effective in the microbial reduction of multispecies biofilm composed of early colonizing microorganisms.

Streptococcus sanguis brain abscess as an initial manifestation of pulmonary arteriovenous malformation

Pulmonary arteriovenous malformation is a vascular anomaly that predisposes to complications of paradoxical embolization including stroke and brain abscess. Here, we present a case of brain abscess associated with pulmonary arteriovenous malformation.

Genome analysis of a multidrug-resistant Streptococcus sanguis isolated from a throat swab of a child with scarlet fever

OBJECTIVES

A multidrug-resistant strain of the opportunistic pathogen Streptococcus sanguis (S28) was isolated from a throat swab of a child with scarlet fever as a rare case. Genome sequencing and analysis of strain S28 were performed to gain a better understanding of the multidrug resistance mechanisms of S. sanguis and its relationship with scarlet fever.

METHODS

The genome of S. sanguis S28 was sequenced on a Illumina HiSeq platform. Genome assembly was conducted using SOAPdenovo v.2.04 and the assembled genome sequence was submitted to NCBI for annotation.

RESULTS

The 1 268 358 696bp genome of S. sanguis S28 contains 2287 coding sequences (CDS) with a GC content of 43.2%. Strain S28 possesses four antimicrobial resistance genes (ARGs), which is consistent with phenotypic analysis. A novel transposon with three genes conferring resistance to macrolide-lincosamide-streptogramin B (MLS_B) antibiotics, tetracyclines and aminoglycosides was discovered.

CONCLUSION

To our knowledge, this is the first report of a S. sanguis genome isolated from a throat swab of a child with scarlet fever and the first report of a transposon with three activated ARGs conferring resistance to MLS_B, tetracyclines and aminoglycosides together.

The antibacterial activity of "Satureja hortensis" extract and essential oil against oral bacteria

BACKGROUND

Recently, there has been an increasing growth in research on medical plant's effect on dental plaque bacteria. The aim of this study was to determine the antibacterial effects of Satureja hortensis extract and its essential oil (EO) on Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mutans as important bacteria in early supragingival dental plaque formation.

MATERIALS AND METHODS

In this in vitro study, different concentrations of S. hortensis extract and its EO were prepared using double dilution method. The disc diffusion method was used to determine antibacterial activity. Based on these measurements, the minimal inhibitory concentration value was reported for each bacterium. Antibiotics used as positive controls in this study were erythromycin (15 μg) and tetracycline (30 μg). t-test and ANOVA were used for statistical analysis (P < 0.05).

RESULTS

Aqueous and methanolic extract did not show significant antibacterial activity, but the EO significantly inhibited the growth of the test bacteria compared to positive control (P < 0.05). High concentrations of EO processed greater antimicrobial effects against three oral bacteria than other low concentrations (P < 0.0001). For S. mutans, the inhibition effect of tetracycline 30 μg was similar with 50% (P = 0.789) and 25% (P = 0.158) dosages of the EO. For S. salivarius, the effect of tetracycline 30 μg was similar to 50% dosages of the EO (P = 0.122). For S. sanguis, the effect of erythromycin 15 μg was lower than 50% (P = 0.0006) and 25% (P = 0.003) dosages of the EO. The inhibition effects of all concentrations of EO were higher for S. sanguis. S. salivarius and S. sanguis are more sensitive than S. mutans to S. hortensis EO.

CONCLUSION

Due to the strong antibacterial effect of S. hortensis EO on the oral bacteria growth, it can be served as herbal mouth rinse, while to confirm this antibacterial effect, further clinical studies are necessary.

Effectiveness of Salvadora persica extracts against common oral pathogens

Objective

The purpose of this study was to evaluate the antibacterial activity of ethanol and hexane extracts of Salvadora persica against common oral pathogens.

Materials and methods

Well diffusion, Minimum Inhibition Concentration (MIC), Minimum Bactericidal Concentration (MBC), and Broth microdilution tests were used to determine the optimum antimicrobial concentrations of S. persica extracts against Streptococcus mutans (S. mutans), Streptococcus sanguis (S. sanguis), and Streptococcus salivarius (S. salivarius) over 1, 3, 6, 12, and 24 h. Chlorhexidine (CHX) 0.2% was used as a positive control.

Results

The findings showed that the microbial activity of both extracts was concentration-dependent. Ethanol extract of S. persica at 25, 50, and 100 mg/ml had more growth inhibitory effect against all isolates compared to hexane extract. In addition, ethanol extract at 8 mg/ml (MBC value) was able to eradicate the growth of all isolates. S. sanguis and S. salivarius were very sensitive to hexane extract and required 4 mg/ml (MBC value) for their eradication while S. mutans was the most resistant (MBC = 8 mg/ml).The statistical findings of CFU counts showed no significant difference (p = 1.000) in antibacterial effectiveness between the two extracts against all isolates. A significant decline overtime in CFU counts was noted, except at 12 h and 24 h where no significant difference (p = 0.793) was observed and was comparable to CHX.

Conclusion

Ethanol and hexane extracts of S. persica were found to exhibit maximum antimicrobial activity against S. mutans, S. sanguis and S. salivarius at high concentrations.

Combinatorial effects of arginine and fluoride on oral bacteria

Dental caries is closely associated with the microbial disequilibrium between acidogenic/aciduric pathogens and alkali-generating commensal residents within the dental plaque. Fluoride is a widely used anticaries agent, which promotes tooth hard-tissue remineralization and suppresses bacterial activities. Recent clinical trials have shown that oral hygiene products containing both fluoride and arginine possess a greater anticaries effect compared with those containing fluoride alone, indicating synergy between fluoride and arginine in caries management. Here, we hypothesize that arginine may augment the ecological benefit of fluoride by enriching alkali-generating bacteria in the plaque biofilm and thus synergizes with fluoride in controlling dental caries. Specifically, we assessed the combinatory effects of NaF/arginine on planktonic and biofilm cultures of Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis with checkerboard microdilution assays. The optimal NaF/arginine combinations were selected, and their combinatory effects on microbial composition were further examined in single-, dual-, and 3-species biofilm using bacterial species-specific fluorescence in situ hybridization and quantitative polymerase chain reaction. We found that arginine synergized with fluoride in suppressing acidogenic S. mutans in both planktonic and biofilm cultures. In addition, the NaF/arginine combination synergistically reduced S. mutans but enriched S. sanguinis within the multispecies biofilms. More importantly, the optimal combination of NaF/arginine maintained a "streptococcal pressure" against the potential growth of oral anaerobe P. gingivalis within the alkalized biofilm. Taken together, we conclude that the combinatory application of fluoride and arginine has a potential synergistic effect in maintaining a healthy oral microbial equilibrium and thus represents a promising ecological approach to caries management.

In vitro antagonistic growth effects of Lactobacillus fermentum and lactobacillus salivarius and their fermentative broth on periodontal pathogens

As lactobacilli possess an antagonistic growth property, these bacteria may be beneficial as bioprotective agents for infection control. However, whether the antagonistic growth effects are attributed to the lactobacilli themselves or their fermentative broth remains unclear. The antagonistic growth effects of Lactobacillus salivarius and Lactobacillus fermentum as well as their fermentative broth were thus tested using both disc agar diffusion test and broth dilution method, and their effects on periodontal pathogens, including Streptococcus mutans, Streptococcus sanguis, and Porphyromonas gingivalis in vitro at different concentrations and for different time periods were also compared. Both Lactobacillus salivarius and Lactobacillus fermentum and their concentrated fermentative broth were shown to inhibit significantly the growth of Streptococcus mutans, Streptococcus sanguis, and Porphyromonas gingivalis, although different inhibitory effects were observed for different pathogens. The higher the counts of lactobacilli and the higher the folds of concentrated fermentative broth, the stronger the inhibitory effects are observed. The inhibitory effect is demonstrated to be dose-dependent. Moreover, for the lactobacilli themselves, Lactobacillus fermentum showed stronger inhibitory effects than Lactobacillus salivarius. However, the fermentative broth of Lactobacillus fermentum showed weaker inhibitory effects than that of Lactobacillus salivarius. These data suggested that lactobacilli and their fermentative broth exhibit antagonistic growth activity, and consumption of probiotics or their broth containing lactobacilli may benefit oral health.

Assessing the Effect of Pineapple Extract Alone and in Combination With Vancomycin on Streptococcus sanguis

BACKGROUND

Periodontitis is a major problem that affects a large number of patients in the society. Various treatment alternatives have been proposed to control this pathologic condition. Streptococcus sanguis is one of the countless pathogens involved in periodontitis.

OBJECTIVES

The current study aimed to assess the efficacy of pineapple extract per se and in synergy with vancomycin on the growth activity of S. Sanguis.

MATERIALS AND METHODS

An experimental study was designed to determine the minimum inhibitory concentration (MIC) of Pineapple extract per se and in conjunction with vancomycin. The study was carried out in three stages. Serial concentrations of the aqueous pineapple extract, vancomycin, and pineapple plus vancomycin were prepared by broth microdilution technique respectively and were exposed to the standard laboratory strain of S. sanguis (10556 ATCC). The lowest concentration of the pineapple extract and the mixed pineapple/vancomycin solution which inhibited bacterial growth was recorded as the MIC.

RESULTS

The minimum inhibitory concentration of vancomycin was determined 1 µg/ ml. The pineapple extract failed to show any inhibitory effects per se, however, once added to vancomycin, it reduced the MIC to 0.5µg/ml.

CONCLUSION

Prescription of pineapple extract along with antibiotics increases the antibacterial effects of the drug, therefore reduces the minimum inhibitory concentration of the antibiotic.