Reduction In Colony-forming Units Research Articles

Effects of D-Tagatose on Cariogenic Risk: A Systematic Review of Randomized Clinical Trials

Dental caries remains a prevalent chronic disease driven by dysbiosis in the oral biofilm, with Streptococcus mutans playing a central role in its pathogenesis. Objective: This study aimed to assess the effect of D-tagatose on cariogenic risk by analyzing randomized clinical trials (RCTs). Methods: A systematic literature review was conducted targeting RCTs published up to 2024 in eight databases and two gray literature sources. The search strategy utilized Medical Subject Headings (MeSHs) and relevant keywords combined via Boolean operators using the query “Tagatose OR D-tagatose AND Dental Caries”. Eligible studies must evaluate the impact of D-tagatose on cariogenic risk, as indicated by reductions in colony-forming units (CFUs) and improvements in salivary pH levels in treatment groups. Results: From 1139 retrieved records, three studies met the inclusion criteria. These studies consistently demonstrated significant reductions in CFU counts and improvements in salivary pH levels in groups treated with D-tagatose compared to controls using other non-caloric sweeteners or placebos (p < 0.01). However, the quality of the evidence was heterogeneous, with certain methodological concerns. Conclusions: Although the findings suggest potential benefits of D-tagatose in reducing cariogenic risk, limitations such as small sample sizes and variability in study methodologies warrant caution. Further robust investigations are needed to substantiate these promising results and support the integration of D-tagatose into oral care formulations aimed at reducing cariogenic risk.

Efficacy of non -thermal pressure plasma versus other modalities for disinfection of primary root canals

BackgroundEndodontic treatment aims in the preservation of extremely carious primary teeth. For root canal therapy to be successful, root canals must be properly prepared and effectively irrigated .Therefore, it is necessary to select the proper root canal disinfection method to preserve the primary tooth.ObjectiveThis research was carried out to compare non-thermal pressure plasma (NTPP), diode laser, propolis, and chlorhexidine (CHX) efficacy for disinfection of deciduous anterior root canals contaminated with Enterococcus Faecalis (E. faecalis) after sterilization by gamma radiation.MethodsIn this study, forty extracted single-rooted primary anterior teeth were used. All teeth were cleaned, disinfected, and stored till use. Gaining access was provided till reaching the orifices of canals, all pulp tissue debris was removed, and root canals of all teeth were prepared. Standardized 8 mm root length was obtained through crown decronation below the cemento-enamel junction. Samples were sterilized by gamma radiation then the bacterial suspension was inoculated inside root canals. Specimens divided into four main groups; ten samples each group. Group I: Samples irrigated with chlorhexidine. Group II: Samples treated with diode laser. Group III: Samples irrigated with Ethanolic extract of propolis. Group IV: Samples treated with NTPP.ResultsA significant difference was found between values measured before and after four irrigation types (p < 0.001) for CHX, Diode Laser, NTPP and (P = 0.035) for Propolis. The highest values of colony reduction measured before and after irrigation were for NTPP (4.06 ± 0.88). Maximum reduction in colony-forming units was recorded in the NTPP group (98.79%), while the lowest reduction in colony-forming units was recorded in Propolis group (81.99%).ConclusionAll tested methods (CHX, NTPP, Diode laser and Propolis) decreased colony count, with the highest reduction noted in group treated by NTPP and the least reduction noticed in Propolis treated group.

Photodynamic antibacterial evaluation of polydopamine nanoparticle optimised Curcumin Longa against endodontic biofilm-An in-vitro study.

This study aims to evaluate the effect of antimicrobial photodynamic therapy(aPDT) with polydopamine nanoparticle functionalised with Curcuma longa(nPD-Cur) against root canal biofilm. nPD-Cur was prepared and characterised using Scanning Electron Microscopy(SEM), dynamic light scattering(DLS), Fourier-transform infrared spectroscopy(FTIR) and Ultraviolet visual(UV/Vis) spectrophotometry. Root sections (10 mm length) were obtained from 53 single-rooted human premolars and chemo-mechanically prepared followed by inoculation with E. faecalis. All the specimens were randomly divided into five groups(n = 10) and irrigated (Group 1-Saline; Group 2-2.5% Sodium hypochlorite(NaOCl); Group 3-Cur; Group 4-nPD; and Group 5-nPD-Cur) followed by diode irradiation and analysed for reduction in colony-forming units(CFU)/mL, bacterial viability using Confocal Laser Scanning Microscopy(CLSM) and SEM for biofilm disruption. Results were analysed using one-way ANOVA followed by post hoc Tukey's test for pairwise comparison (p < 0.05). nPD-Cur revealed the characteristic absorption patterns. The antimicrobial potency was highest for NaOCl followed by nPD > Cur-nPD > Cur.

Photodynamic disruption of a polymicrobial biofilm of two periodontal species using indocyanine green-loaded nanospheres

ObjectiveAntimicrobial photodynamic therapy (aPDT) is considered a potential treatment for biofilm infections, which have become an increasing health issue because of the rise in antimicrobial resistance. This study aimed to evaluate the bactericidal effect of aPDT using indocyanine green-loaded nanospheres with chitosan coating (ICG-Nano/c) against polymicrobial periodontal biofilms. MethodsComposite biofilms of Porphyromonas gingivalis and Streptococcus gordonii were constructed in 96-well plates, and aPDT with ICG-Nano/c and an 810 nm diode laser was performed either by direct irradiation or transmitting irradiation through a 3-mm-thick gingival model. The efficacy of ICG-Nano/c-based aPDT was compared with antibiotics (minocycline and amoxicillin). Additionally, attenuated aPDT under sublethal conditions was used to investigate gene expression related to the antioxidant response (oxyR and sod of P. gingivalis) and biofilm formation via quorum sensing (luxS of both species) with real-time polymerase chain reaction. ResultsICG-Nano/c-based aPDT significantly reduced the bacterial load in the biofilm, achieving at least a 2 log10 reduction in colony-forming units within 5 min for both irradiation methods. After 6 h of treatment, the bactericidal effects of aPDT and antibiotics were similar, but after 32 h, antibiotics were more effective, particularly against P. gingivalis. Attenuated aPDT showed a slight increase in sod expression in P. gingivalis, while luxS expression decreased in both bacteria. ConclusionThe ICG-Nano/c-based aPDT system exerted a certain degree of bactericidal activity against a composite biofilm of periodontal bacteria. Therefore, it has potential as an alternative option or adjunctive therapy to conventional antibiotics in periodontal treatment.

Povidone-iodine and silver nitrate are equally effective in eradicating staphylococcal biofilm grown on a titanium surface: an in-vitro analysis

BackgroundThere is no consensus on the irrigation solution and concentration that should be used when performing a debridement, antibiotics, and implant retention (DAIR)-surgery. AimTo determine the minimum-biofilm-eradication-concentration of five antibacterial solutions and compare their efficacy in eradicating Staphylococcal biofilm embedded on a titanium surface. MethodsMethicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) ATCC standard strains were grown over porous Ti-6Al-4V acetabular screw-caps. Antibacterial solutions were povidone iodine, rifampicin, silver nitrate, copper sulphate, chlorhexidine. Minimum biofilm eradication concentration (MBEC) values were calculated for MSSA and MRSA. After 24 hours, screw-caps were exposed 3 minutes to each solution. Bacterial separation from each specimen was performed with vortex agitation and footprint on agar plate in triplicate. Colony forming units (CFU) were counted pre- and post-agitation, and the delta of CFU/ml was calculated for each solution. A three-fold log reduction in CFU was considered a measure of solution efficacy. Comparison between groups was made with Fisher’s test. FindingsMBEC values for MSSA and MRSA, respectively, were as follows: 8000 ug/mL and 16000 ug/ml for povidone iodine; 64 ug/mL and 128 ug/mL for rifampicin; 10000 ug/mL and 5120 ug/mL for silver nitrate; 900 ug/mL and 900 ug/mL for copper sulphate; 16 ug/mL and 32 ug/mL for chlorhexidine. Rifampicin, copper sulphate and chlorhexidine were ineffective against MSSA and MRSA biofilm compared to povidone iodine (p<0.01) and silver nitrate (p=0.015) that had a delta CFU reduction >8 log. Povidone iodine and silver nitrate showed negative footprints without visible MSSA (p=0.005) and MRSA (p=0.014). ConclusionsPovidone iodine and silver nitrate were the only irrigating solutions capable of eradicating at least 99.9% of 24-hour biofilm.

Not All Antiseptic Solutions Are Equivalent in Removing Biofilm: A Comparison Across Different Orthopaedic Surfaces.

Antiseptic solutions are commonly utilized during total joint arthroplasty (TJA) to prevent and treat periprosthetic joint infection (PJI). The purpose of this study was to investigate which antiseptic solution is most effective against methicillin-sensitive Staphylococcus aureus (MSSA) and Escherichia coli biofilms established in vitro on orthopaedic surfaces commonly utilized in total knee arthroplasty: cobalt-chromium (CC), oxidized zirconium (OxZr), and polymethylmethacrylate (PMMA). MSSA and E. coli biofilms were grown on CC, OxZr, and PMMA discs for 24 and 72 hours. Biofilm-coated discs were treated with control or various antiseptic solutions for 3 minutes. Solutions included 10% povidone-iodine, a 1:1 mixture of 10% povidone-iodine plus 3% hydrogen peroxide, diluted povidone-iodine, 0.05% chlorhexidine gluconate, and a surfactant-based formulation of ethanol, acetic acid, sodium acetate, benzalkonium chloride, and water. Following treatment, discs were sonicated to quantify adherent bacteria or underwent imaging with scanning electron microscopy to identify biofilm. Antiseptic solutions were considered efficacious if they produced a 3-log (1,000-fold) reduction in colony-forming units compared with controls. On both OxZr and CC, 10% povidone-iodine with hydrogen peroxide eradicated all MSSA, and it achieved clinical efficacy on PMMA at both 24-hour MSSA biofilm (p < 0.0002) and 72-hour MSSA biofilm (p = 0.002). On 72-hour MSSA biofilm, 10% povidone-iodine eradicated all bacteria on OxZr and CC, and it achieved clinical efficacy on PMMA (p = 0.04). On 24-hour MSSA biofilm, 10% povidone-iodine achieved efficacy on all surfaces (all p < 0.01). The surfactant-based formulation only achieved clinical efficacy on 72-hour MSSA biofilms on CC (p = 0.04) and OxZr (p = 0.07). On 72-hour E. coli biofilm, 10% povidone-iodine with or without hydrogen peroxide achieved clinical efficacy on all surfaces. No other solution achieved clinical efficacy on either MSSA or E. coli. Antiseptic solutions vary considerably in efficacy against bacterial biofilm. The 10% povidone-iodine solution with or without hydrogen peroxide consistently removed MSSA and E. coli biofilms on multiple orthopaedic surfaces and should be considered for clinical use. Clinicians should be aware of the differences in the efficacy of antiseptic solutions on different orthopaedic surfaces when treating MSSA or E. coli biofilms.

Treatment of Mycobacterium tuberculosis infected macrophages with Rifabutin loaded β-glucan microparticles induces macroautophagy mediated bacillary killing

Tuberculosis (TB), attributable to Mycobacterium tuberculosis (M.tb.), constitutes a formidable global health challenge, particularly with the proliferation of multidrug-resistant (MDR-TB) strains. The efficacious clearance of M.tb. from host cells is imperative for mitigating infection and averting disease progression. Autophagy, an intricate cellular mechanism for degrading and recycling biomolecules, plays a pivotal role in the immune response to M.tb. by facilitating the degradation of intracellular pathogen through the formation of autophagosomes and their subsequent fusion with lysosomes. The present study elucidates the therapeutic efficacy of Rifabutin loaded YDGP (DYDGP) microparticles within M.tb.infected macrophage. Our results show that the administration of DYDGP improve the membrane integrity of macrophage infected with H37Rv as well as MDR strains, as compared to that of untreated controls at 30 min, 6 h and 24 h post-exposure time points. DCFHDA staining elucidated that DYDGP treatment significantly enhances intracellular reactive oxygen species (ROS) production compared to blank YDGP, even in the presence of NOX-2 inhibitors. Furthermore, DYDGP promotes the biogenesis of acidic vesicular organelles and phago-lysosomal maturation, as corroborated by acridine orange and Lysotracker Red staining. Immunofluorescence and dansylcadaverine dual staining data evidenced that DYDGP treatment enhances autophagosome formation, autophagy induction and LC3 puncta formation within M.tb. infected macrophage at both 30 min and 24 h post-exposure time points. Further, protein expression analyses demonstrated that DYDGP treatment enhances the expression levels of NOX-2 and LC3, thereby confirming autophagy induction within M.tb. infected macrophage. Antimycobacterial efficacy assessments revealed that DYDGP treatment engendered significant reductions in colony-forming units (CFUs) of H37Rv (64, 40, 19), MDR32420 (44, 35, 18), MDR32422 (44, 39, 21), and MDR32521 (38, 22, 18) after 30 min, 24 h, and 48 h, exposure respectively. These findings accentuate DYDGP's potential to substantially attenuate M.tb. burden, including the addressal of MDR strains, thereby positioning it as a promising adjunctive therapy for augmenting TB treatment.

Efficacy of UV-C 254 nm Light and a Sporicidal Surface Disinfectant in Inactivating Spores from Clostridioides difficile Ribotypes In Vitro.

Clostridioides difficile is widely recognised as one of the most common causes of healthcare-associated C. difficile infections due to the ability of spores to survive for prolonged periods in the hospital environment. This study aimed to evaluate the efficacy of UV-C 254 nm light in the inactivation of the spores of different C. difficile ribotypes on brain heart infusion (BHI) agar plates or in phosphate-buffered saline (PBS) with varying spore densities. Furthermore, the effectiveness of a sporicidal surface disinfectant against C. difficile spores was determined on different surfaces. Spore suspensions of different C. difficile strains in the range of 105-107 colony-forming units (CFUs) mL-1 were inoculated on BHI agar plates or in PBS and exposed to UV-C light for up to 30 min. Additionally, a spore suspension of 103-105 CFUs was spread over a 1 cm2 test area on different surfaces, and sporicidal surface wipes were used according to the manufacturer's instructions. The findings demonstrated that spores of C. difficile ribotypes exhibited a complete reduction in log10 CFU on BHI agar plates and PBS following 20 min of exposure to a UV-C dose of 2208 mJ cm-2. The surface wipes with sporicidal properties demonstrated efficacy in reducing the number of C. difficile spores on the Formica, stainless steel, and plastic surfaces by 2.03-3.53 log10. The present study demonstrates that moist surfaces or liquids can enhance the efficacy of UV-C treatment in reducing C. difficile spores. This approach may be applicable to the surfaces of healthcare facilities and to water disinfection systems.

Comparison of ultraviolet C light and isopropyl alcohol for the disinfection of cellular phones in a paediatric intensive care unit setting.

A considerable proportion of cellular phones (cell phones) used by healthcare workers (HCWs) have been shown to be contaminated with pathogenic micro-organisms, making these devices reservoirs to infect susceptible patients. Although many units have well-defined infection control protocols, methods for the decontamination of cell phones are scarce. To compare the efficacy of ultraviolet C (UVC) light with that of 70% isopropyl alcohol in disinfecting cell phones used by HCWs in a paediatric intensive care unit (ICU). A randomised controlled study in a paediatric ICU setting was conducted. Cell phones of HCWs or other personnel entering the ICU were swabbed prior to and after decontamination with either the 70% isopropyl alcohol or UVC light method. The reduction ratio of colony-forming units (CFUs) before and after intervention was analysed using the Mann-Whitney U-test. In addition, the effectiveness of the disinfection methods was compared using the Wilcoxon signed-rank paired test. A total of 74 cell phones were acquired from HCWs working in the paediatric ICU. After excluding 5, 69 samples were therefore available for statistical analysis, with 34 samples subjected to disinfection using 70% isopropyl alcohol-based swabs and 35 samples treated with UVC light disinfection. Disinfection with 70% isopropyl alcohol (z=5.16; p<0.000001) and with UVC light (z=3.28; p<0.005) were individually statistically significantly effective in reducing CFUs. The CFU reduction ratio indicated that disinfection using a 70% isopropyl alcohol solution was 67% more effective than UVC light disinfection (Mann-Whitney U-test score 968; p<0.001). Although both 70% isopropyl alcohol and UVC light disinfection effectively reduced CFUs following decontamination, 70% isopropyl alcohol was determined to be much more effective.

Formulation and Optimization of Solid Lipid Nanoparticle-based Gel for Dermal Delivery of Linezolid Using Taguchi Design.

Linezolid (LNZ) is a synthetic oxazolidinone antibiotic approved for the treatment of uncomplicated and complicated skin and soft tissue infections caused by gram-positive bacteria. Typically, LNZ is administered orally or intravenously in most cases. However, prolonged therapy is associated with various side effects and life threatening complications. Cutaneous application of LNZ will assist in reducing the dose, hence minimizing the unwanted side/adverse effects associated with oral administration. Dermal delivery provides an alternative route of administration, facilitating a local and sustained concentration of the antimicrobial at the site of infection. The current research work aimed to formulate solid lipid nanoparticles (SLNs) based gel for dermal delivery of LNZ in the management of uncomplicated skin and soft tissue infections to maximise its benefits and minimise the side effects. SLNs were prepared by high-shear homogenisation and ultrasound method using Dynasan 114 as solid lipid and Pluronic F-68 as surfactant. The effect of surfactant concentration, drug-to-lipid ratio, and sonication time was investigated on particle size, zeta potential, and entrapment efficiency using the Taguchi design. The main effect plot of means and signal-to-noise ratio were generated to determine the optimized formulation. The optimized batch was formulated into a gel, and ex-vivo permeation study, in-vitro and in-vivo antibacterial activity were conducted. The optimised process parameters to achieve results were 2% surfactant concentration, a drug-to-lipid ratio of 1:2, and 360 s of sonication time. The optimized batch was 206.3± 0.17nm in size with a surface charge of -24.4± 4.67mV and entrapment efficiency of 80.90 ± 0.45%. SLN-based gel demonstrated anomalous transport with an 85.43% in vitro drug release. The gel showed a 5 cm zone of inhibition while evaluated for in vitro antibacterial activity against Staphylococcus aureus. Ex-vivo skin permeation studies demonstrated 20.308% drug permeation and 54.96% cutaneous deposition. In-vivo results showed a significant reduction in colony-forming units in the group treated with LNZ SLN-based gel. Ex-vivo studies ascertain the presence of the drug at the desired site and improve therapy. In-vivo results demonstrated the ability of SLN-based gel to significantly reduce the number of bacteria in the stripped infection model. The utilization of SLN as an LNZ carrier holds significant promise in dermal delivery.

Netupitant Exhibits Potent Activity on Mycobacterium tuberculosis Persisters.

In Mycobacterium tuberculosis (Mtb), persisters are genotypically drug-sensitive bacteria that nonetheless survive antibiotic treatment. Persisters represent a significant challenge to shortening TB treatment and preventing relapse, underscoring the need for new therapeutic strategies. In this study, we screened 2,336 FDA-approved compounds to identify agents that enhance the sterilizing activity of standard anti-TB drugs and prevent the regrowth of persisters. Netupitant (NTP), an FDA-approved antiemetic, emerged as a promising candidate with bacteriostatic activity on its own. However, in combination with isoniazid (INH) and rifampicin (RIF), NTP eliminated viable Mtb cells within 7 days, achieving a >6-log reduction in colony-forming units (CFUs) compared to the 2.5-log reduction observed with INH-RIF alone. NTP also demonstrated broad-spectrum efficacy, enhancing the activity of multiple TB drugs, including ethambutol, moxifloxacin, amikacin, and bedaquiline. Notably, NTP retained its potency under hypoxic and caseum-mimicking conditions, both of which are known to enrich for non-replicating, drug-tolerant cells. Interestingly, under hypoxic conditions, NTP demonstrated strong tuberculocidal activity, achieving an approximate 4-log CFU reduction, whereas high-dose INH-RIF was ineffective. Transcriptomic analysis revealed that NTP primarily disrupts cellular bioenergetics, with significant downregulation observed in activities associated with the electron transport chain, oxidative phosphorylation, NADH-ubiquinone oxidoreductase, succinate dehydrogenase, and ATP synthesis. While further studies are required to decipher the mechanism of action and resistance profile of NTP, and to assess its in vivo efficacy, these findings underscore its potential as a promising adjunct to existing TB therapies.

A silver lining in MRSA treatment: The synergistic action of poloxamer-stabilized silver nanoparticles and methicillin against antimicrobial resistance

BackgroundIncreasing antibiotic resistance in bacterial infections, including drug-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA), necessitates innovative therapeutic solutions. Silver nanoparticles are promising for combating infections, but toxicity concerns emphasize the importance of factors like dosage, size, shape, and surface chemistry. Hence, exploring poloxamer as a stabilizing agent to reduce its toxicity and enhance the antibacterial effect on MRSA is investigated. MethodsSilver nanoparticles stabilized with poloxamer (AgNPs@Pol) were synthesized through the chemical reduction method and characterized using UV–visible spectrophotometer, HR-TEM, DLS, and Zeta potential measurements. Subsequently, the antibacterial activity of AgNPs@Pol alone and in combination with methicillin against MRSA and methicillin-susceptible S. aureus (MSSA) was evaluated using the broth microdilution method. ResultsAgNPs@Pol showed significant efficacy against MRSA and MSSA, achieving a 100 % reduction in colony-forming units (CFU) at 9.7 μg/ml. The minimum inhibitory concentration (MIC) against MRSA and MSSA was 8.6 μg/ml and 4.3 μg/ml, respectively. A synergistic effect was observed when AgNPs@Pol was combined with methicillin. Treatment with AgNPs@Pol increased reactive oxygen species (ROS) production in both strains, contributing to its antibacterial activity. Real-time qPCR analysis indicated the downregulation of genes involved in antimicrobial resistance and cell adhesion in both strains. Further, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay demonstrated low cytotoxicity for AgNPs@Pol against MCF-7, MG-63, and NIH-3T3 cell lines. ConclusionThe developed AgNPs@Pol demonstrated extensive colloidal stability, potent antibacterial activity and synergistic effect with methicillin against MRSA and MSSA. Further studies in primary cells and in vivo models may validate its potential for clinical applications.

Shear-Thinning Extrudable Hydrogels Based on Star Polypeptides with Antimicrobial Properties.

Hydrogels with low toxicity, antimicrobial potency and shear-thinning behavior are promising materials to combat the modern challenges of increased infections. Here, we report on 8-arm star block copolypeptides based on poly(L-lysine), poly(L-tyrosine) and poly(S-benzyl-L-cysteine) blocks. Three star block copolypeptides were synthesized with poly(S-benzyl-L-cysteine) always forming the outer block. The inner block comprised either two individual blocks of poly(L-lysine) and poly(L-tyrosine) or a statistical block copolypeptide from both amino acids. The star block copolypeptides were synthesized by the Ring Opening Polymerization (ROP) of the protected amino acid N-carboxyanhydrides (NCAs), keeping the overall ratio of monomers constant. All star block copolypeptides formed hydrogels and Scanning Electron Microscopy (SEM) confirmed a porous morphology. The investigation of their viscoelastic characteristics, water uptake and syringe extrudability revealed superior properties of the star polypeptide with a statistical inner block of L-lysine and L-tyrosine. Further testing of this sample confirmed no cytotoxicity and demonstrated antimicrobial activity of 1.5-log and 2.6-log reduction in colony-forming units, CFU/mL, against colony-forming reference laboratory strains of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, respectively. The results underline the importance of controlling structural arrangements in polypeptides to optimize their physical and biological properties.

Effects of photodynamic therapy using bisdemethoxycurcumin combined with melatonin or acetyl-melatonin on C. Albicans

The current study aims to explore the efficacy of antifungal photodynamic therapy (PDT) on C. albicans biofilms by combining photosensitizers, bisdemethoxycurcumin (BDMC), and melatonin (MLT) or acetyl-melatonin (AcO-MLT). Additionally, the relationship between different types of reactive oxygen species and PDT’s antifungal efficacy was investigated. BDMC, MLT and AcO-MLT were applied, alone and in combination, to 48-hour C. albicans biofilm cultures (n = 6/group). Blue and red LED light (250 mW/cm2 with 37.5 J/cm2 for single or 75 J/cm2 for dual photosensitizer groups) were used to irradiate BDMC groups and MLT/AcO-MLT groups, respectively. For combination groups, blue LEDs and subsequently red LEDs were used. Drop plate assays were performed at 0, 1 and 6 h post-treatment. Colony forming units (CFUs) were then counted after 48 h. Hydroxyl radicals and singlet oxygen were measured using fluorescence spectroscopy and electron spin resonance (ESR) spectroscopy. Additionally, cell cytotoxicity was tested on human oral keratinocytes. Significant CFU reductions were observed with combinations 20 µM BDMC + 20 µM AcO-MLT and 60 µM BDMC + 20 µM MLT at 0 and 1 h post-treatment, respectively. Singlet oxygen production increased with the addition of MLT/AcO-MLT and had moderate-substantial correlations with inhibition at all times. Hydroxyl radical production was not significantly different from the control. Additionally, BDMC exhibited subtle cytotoxicity on human oral keratinocytes. PDT using BDMC + MLT or AcO-MLT, with blue and red LED light, effectively inhibits C. albicans biofilm through singlet oxygen generation. Melatonin acts as a photosensitizer in PDT to inhibit fungal infection.

Exploring Myrrh Oil as a Natural Antimicrobial Agent Against Oral Pathogens: An In Vitro Research

Background: While contemporary pharmaceuticals play a critical role in managing oral infections, there remain persistent concerns regarding their chemical composition and potential adverse effects. This apprehension has led to an increased focus on exploring natural alternatives, particularly herbal substances, for their potential therapeutic benefits in oral health. Aim: This study aimed to examine the antibacterial properties of myrrh oil against common oral bacteria, including Candida, Escherichia coli, Klebsiella, and Staphylococcus aureus, and to assess its suitability as a natural alternative in oral healthcare. Methods: Oral swabs were obtained from 50 individuals from various socioeconomic backgrounds. The isolated organisms were cultivated on different types of media and identified using established microbiological methods. Bacterial growth inhibition was evaluated by culturing subsequent cultures on Muller-Hinton agar with myrrh oil. This agar medium was selected for its suitability in evaluating myrrh oil’s suppressive impact on oral bacteria proliferation. Results: Candida demonstrated abundant proliferation on the control media but showed a reduction in colony-forming units when treated with myrrh oil. E. coli, Klebsiella, and Staphylococcus aureus exhibited decreased growth and suppressed colony formation when exposed to myrrh oil. Conclusion: These findings indicate that myrrh oil can prevent the growth of oral bacteria, making it a promising natural antibacterial agent for managing oral health. Additional investigations are needed to examine the safety, ideal dosage, and clinical feasibility of this treatment.

A far ultraviolet-C light technology is effective for decontamination of items in proximity to sinks and is enhanced by a far UV-C reflective surface.

Dispersal of gram-negative bacilli from sink drains has been implicated as a source of transmission in multiple outbreaks. In an acute care hospital, we assessed how often patient care supplies and other frequently touched items were within 1 meter of sink drains. We tested the efficacy of a ceiling-mounted far ultraviolet-C (UV-C) light technology for decontamination of sink bowls and surfaces near sinks with and without a wall-mounted film that reflects far UV-C light. Of 190 sinks assessed, 55 (29%) had patient care supplies or other frequently touched items within 1 meter of the drain. The far UV-C technology reduced Pseudomonas aeruginosa, Enterobacter cloacae and Candida auris on steel disk carriers by ≥1.5 log10 colony-forming units (CFU) in 45 minutes. On inoculated real-world items, ≥1.9 log10 CFU reductions in P. aeruginosa were achieved on sites in line with the light source versus 0.4-1.8 log10 CFU reductions on shaded surfaces. The addition of the reflective surface significantly enhanced efficacy in shaded sites (P < 0.01). In a hospital setting, patient care supplies and other frequently touched items were often in proximity to sinks. The far UV-C light technology could potentially be useful for sink decontamination in high-risk areas.

The Effect of Nanoparticles Against Streptococcus mutans in the Orthodontic Primer Used for Aligner Attachment: An In Vitro Study.

Objective This study investigates the antimicrobial properties of silver (1%) and chitosan (1%) nanoparticles against Streptococcus mutans (S. mutans) when added to an orthodontic primer used for aligner attachments. While aligner treatments are becoming increasingly popular for their aesthetics and convenience, their attachments can create retention sites for bacteria, potentially leading to white spot lesions (WSLs). This in vitro study aims to address this issue by enhancing the antimicrobial efficacy of aligner primers. Methodology Thirty freshly extracted teeth were classified into the following three groups: Group A with the standard primer, Group B with chitosan nanoparticles mixed in the primer, and Group C with silver nanoparticles mixed in the primer. The samples were incubated with S. mutans and bacterial colonies were counted at 12, 24, 48, and 72 hours. Results The results showed a significant reduction in colony-forming units (CFUs) in the groups with nanoparticles compared to the control group, with silver nanoparticles exhibiting a higher antimicrobial effect than chitosan. Conclusions This study suggests that incorporating silver nanoparticles into orthodontic primers can effectively reduce bacterial growth, potentially improving oral hygiene and reducing the risk of WSLs in patients undergoing aligner treatment.

Drug delivery and antibiofilm efficacy of nano silver fluoride sustained release orthodontic elastomerics against Streptococcus mutans

We aimed to investigate the chemical and physical properties of nano silver fluoride sustained release orthodontic elastomerics (NSF-RE) and determine their antimicrobial and antibiofilm formation activities against Streptococcus mutans. Orthodontic elastomerics were dip-coated with NSF solution in ethyl cellulose (EC) and polyethylene glycol 6000 (PEG). The studied groups included NSF (no EC/PEG), NSF-E (EC), NSF-EP1 (EC:PEG, 4:1), and NSF-EP2 (EC:PEG, 2:1). The cumulative release of silver nanoparticles (AgNPs) and fluoride, along with the compatibility of the tensile force with orthodontic brackets, was evaluated. The antimicrobial activity was evaluated using an agar diffusion test. The inhibition of biofilm formation was evaluated using colony-forming units (CFUs), biofilm thickness, and the live/dead cell ratio. NSF-RE containing EC sustained the release of AgNPs and fluoride for > 7 days. Tensile forces were not significantly different among the groups. The inhibition zone was 2.64- and 1.31-fold larger with NSF-EP2 than that with NSF and NSF-E, respectively. NSF-EP2 was the most effective in inhibiting biofilm formation with significant reductions in CFUs, biofilm thickness, and live/dead cell ratio by 57, 86, and 96%, respectively, as compared to those in the control group. Overall, sustained release of AgNPs and fluoride by NSF-RE provides antimicrobial and antibiofilm effects against S. mutans.

S. mutans Antisense vicK RNA Over-Expression Plus Antibacterial Dimethylaminohexadecyl Methacrylate Suppresses Oral Biofilms and Protects Enamel Hardness in Extracted Human Teeth.

Streptococcus mutans (S. mutans) antisense vicK RNA (ASvicK) is a non-coding RNA that regulates cariogenic virulence and metabolic activity. Dimethylaminohexadecyl methacrylate (DMAHDM), a quaternary ammonium methacrylate used in dental materials, has strong antibacterial activity. This study examined the effects of S. mutans ASvicK on DMAHDM susceptibility and their combined impact on inhibiting S. mutans biofilm formation and protecting enamel hardness. The parent S. mutans UA159 and ASvicK overexpressing S. mutans (ASvicK) were tested. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations for planktonic bacteria (MBC-P) and biofilms (MBC-B) were measured. As the ASvicK MBC-B was 175 μg/mL, live/dead staining, metabolic activity (MTT), colony-forming units (CFUs), biofilm biomass, polysaccharide, and lactic acid production were investigated at 175 μg/mL and 87.5 μg/mL. The MIC, MBC-P, and MBC-B values for DMAHDM for the ASvicK strain were half those of the UA159 strain. In addition, combining S. mutans ASvicK with DMAHDM resulted in a significant 4-log CFU reduction (p < 0.05), with notable decreases in polysaccharide levels and lactic acid production. In the in vitro cariogenic model, the combination achieved the highest enamel hardness at 67.1% of sound enamel, while UA159 without DMAHDM had the lowest at 16.4% (p < 0.05). Thus, S. mutans ASvicK enhanced DMAHDM susceptibility, and their combination effectively inhibited biofilm formation and minimized enamel demineralization. The S. mutans ASvicK + DMAHDM combination shows great potential for anti-caries dental applications.

NIR-II triggered Cu(I) phosphide for chemodynamic and photothermal periodontitis treatment: Efficient reduction of bacterial co-aggregation

The synergy between chemodynamic therapy (CDT) and photothermal therapy (PTT) offers a promising antimicrobial strategy for periodontitis, yet faces challenges like complex material structure and limited NIR-I light penetration. Additionally, low endogenous H2O2 levels in biofilm and a focus on bacterial eradication over colonization prevention limit current treatments. To address these issues, we newly introduce a single-material system (Cu3P@PAH@Lox) that integrates dual functionalities to synergistically enhance antimicrobial effects and significantly reduce pathogen co-aggregation. This system utilizes PTT to increase local temperature, boosting •OH production in CDT while downregulating heat shock proteins to enhance PTT efficacy, forming a self-reinforcing feedback loop. Lactate oxidase (Lox) is employed to convert lactate—a metabolite in periodontal biofilm—into H2O2, further amplifying CDT's potential. In vitro Cu3P@PAH@Lox demonstrates a remarkable synergistic effect against dual-species biofilms by more than 2-log reduction of colony-forming unit. Moreover, Cu3P@PAH@Lox exhibits outstanding synergistic antibacterial performances to alleviate inflammation and destruction of tissue in vivo periodontitis model. Furthermore, the mechanism of pathogen co-aggregation disruption by PTT is verified via the Cbe-Ltp1-Ptk1-fimA signaling pathway. This single-material multimodal system we have herein demonstrated for the first time marks a significant advancement in periodontitis treatment, eradicating microbes and preventing bacterial colonization, offering a path to comprehensive periodontal care. Statement of significanceThe synergy between chemodynamic therapy (CDT) and photothermal therapy (PTT) has been considered a promising therapy for periodontitis. Yet, facing challenges, the complex material structure, limited NIR-I light penetration, low endogenous H2O2 level in biofilm, and a focus on bacterial eradication over colonization prevention are still insufficient. This study pioneers a unique, single-material system (Cu3P@PAH@Lox) that synergistically enhances antimicrobial effects and substantially curtails pathogen co-aggregation, advancing periodontitis therapy. By exploiting PTT to elevate local temperatures, thereby increasing hydroxyl radical production in CDT and concurrently suppressing heat shock proteins, the system establishes a potent, self-enhancing loop. Furthermore, lactate oxidase is innovatively utilized to convert lactate from periodontal biofilm into hydrogen peroxide, augmenting the efficacy of CDT. The introduction of Cu3P@PAH@Lox is poised to revolutionize periodontitis treatment, eliminating microbes and impeding bacterial colonization, thereby charting a course for comprehensive periodontal management.