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Microbiology Spectrum May 2024The tenacious biofilms formed by are resistant to conventional antibiotics and current treatments. There is a growing need for novel therapeutics that selectively...
The tenacious biofilms formed by are resistant to conventional antibiotics and current treatments. There is a growing need for novel therapeutics that selectively inhibit biofilms while preserving the normal oral microenvironment. Previous studies have shown that increased levels of cyclic di-AMP, an important secondary messenger synthesized by diadenylate cyclase (DAC), favored biofilm formation in . Thus, targeting DAC is a novel strategy to inhibit biofilms. We screened a small NCI library of natural products using a fluorescence detection assay. (+)-Brazilin, a tetracyclic homoisoflavanoid found in the heartwood of , was identified as one of the 11 "hits," with the greatest reduction (>99%) in fluorescence at 100 µM. The DAC inhibitory profiles of the 11 "hits" established by a quantitative high-performance liquid chromatography assay revealed that (+)-brazilin had the most enzymatic inhibitory activity (87% at 100 µM) and was further studied to determine its half maximal inhibitory concentration (IC = 25.1 ± 0.98 µM). (+)-Brazilin non-competitively inhibits DAC's enzymatic activity ( = 140.0 ± 27.13 µM), as determined by a steady-state Michaelis-Menten kinetics assay. In addition, (+)-brazilin's binding profile with DAC ( = 11.87 µM) was illustrated by a tyrosine intrinsic fluorescence quenching assay. Furthermore, at low micromolar concentrations, (+)-brazilin selectively inhibited the biofilm of (IC = 21.0 ± 0.60 µM) and other oral bacteria. biofilms were inhibited by a factor of 10 in colony-forming units when treated with 50 µM (+)-brazilin. In addition, a significant dose-dependent reduction in extracellular DNA and glucan levels was evident by fluorescence microscopy imaging of biofilms exposed to different concentrations of (+)-brazilin. Furthermore, colonization of on a representative model of enamel using suspended hydroxyapatite discs showed a >90% reduction with 50 µM (+)-brazilin. In summary, we have identified a drug-like natural product inhibitor of biofilm that not only binds to DAC but can also inhibit the function of DAC. (+)-Brazilin could be a good candidate for further development as a potent therapeutic for the prevention and treatment of dental caries.IMPORTANCEThis study represents a significant advancement in our understanding of potential therapeutic options for combating cariogenic biofilms produced by . The research delves into the use of (+)-brazilin, a natural product, as a potent inhibitor of ' diadenylate cyclase (DAC), an enzyme crucial in the formation of biofilms. The study establishes (+)-brazilin as a non-competitive inhibitor of DAC while providing initial insights into its binding mechanism. What makes this finding even more promising is that (+)-brazilin does not limit its inhibitory effects to alone. Instead, it demonstrates efficacy in hindering biofilms in other oral bacteria as well. The broader spectrum of anti-biofilm activity suggests that (+)-brazilin could potentially serve as a versatile tool in a natural product-based treatment for combating a range of conditions caused by resilient biofilms.
Topics: Biofilms; Streptococcus mutans; Isoflavones; Anti-Bacterial Agents; Biological Products; Microbial Sensitivity Tests; Phosphorus-Oxygen Lyases; Bacterial Proteins; Humans
PubMed: 38591917
DOI: 10.1128/spectrum.02418-23 -
JPMA. the Journal of the Pakistan... Mar 2024
Topics: Humans; Chlorhexidine; Streptococcus mutans; Oral Health; Dental Plaque; Saliva; Probiotics; Dental Caries; Colony Count, Microbial
PubMed: 38591271
DOI: 10.47391/JPMA.24-15 -
Journal of Dentistry Jun 2024To incorporate the nanostructured silver vanadate decorated with silver nanoparticles (AgVO) into denture base materials: heat-cured (HC) and 3D printed (3DP) resins, at...
OBJECTIVES
To incorporate the nanostructured silver vanadate decorated with silver nanoparticles (AgVO) into denture base materials: heat-cured (HC) and 3D printed (3DP) resins, at concentrations of 2.5 %, 5 %, and 10 %; and to evaluate the antimicrobial activity in two multi-species biofilm: (1) Candida albicans, Candida glabrata, and Streptococcus mutans, (2) Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus, and the wettability.
METHODS
The AgVO was added to the HC powder, and printed samples were coated with 3DP with AgVO incorporated. After biofilm formation, the antimicrobial activity was evaluated by colony forming units per milliliter (CFU/mL), metabolic activity, and epifluorescence microscopy. Wettability was assessed by the contact angles with water and artificial saliva.
RESULTS
In biofilm (1), HC-5 % and HC-10 % showed activity against S. mutans, HC-10 % against C. glabrata, and HC-10 % and 3DP-10 % had higher CFU/mL of C. albicans. 3DP-5 % had lower metabolic activity than the 3DP control. In biofilm (2), HC-10 % reduced S. aureus and P. aeruginosa, and HC-5 %, 3DP-2.5 %, and 3DP-5 % reduced S. aureus. 3DP incorporated with AgVO, HC-5 %, and HC-10 % reduced biofilm (2) metabolic activity. 3DP-5 % and 3DP-10 % increased wettability with water and saliva.
CONCLUSION
HC-10 % was effective against C. glabrata, S. mutans, P. aeruginosa, and S. aureus, and HC-5 % reduced S. mutans and S. aureus. For 3DP, 2.5 % and 5 % reduced S. aureus. The incorporation of AgVO into both resins reduced the metabolic activity of biofilms but had no effect on C. albicans. The wettability of the 3DP with water and saliva increased with the addition of AgVO.
CLINICAL SIGNIFICANCE
The incorporation of silver vanadate into the denture base materials provides antimicrobial efficacy and can prevent the aggravation of oral and systemic diseases. The incorporation of nanomaterials into printed resins is challenging and the coating is an alternative to obtain the inner denture base with antimicrobial effect.
Topics: Biofilms; Wettability; Streptococcus mutans; Candida albicans; Staphylococcus aureus; Vanadates; Pseudomonas aeruginosa; Silver; Denture Bases; Metal Nanoparticles; Anti-Infective Agents; Candida glabrata; Printing, Three-Dimensional; Materials Testing; Humans; Nanostructures; Silver Compounds; Dental Materials
PubMed: 38583645
DOI: 10.1016/j.jdent.2024.104984 -
JAMA Cardiology Apr 2024The association between antibiotic prophylaxis and infective endocarditis after invasive dental procedures is still unclear. Indications for antibiotic prophylaxis were...
IMPORTANCE
The association between antibiotic prophylaxis and infective endocarditis after invasive dental procedures is still unclear. Indications for antibiotic prophylaxis were restricted by guidelines beginning in 2007.
OBJECTIVE
To systematically review and analyze existing evidence on the association between antibiotic prophylaxis and infective endocarditis following invasive dental procedures.
DATA SOURCES
PubMed, Cochrane-CENTRAL, Scopus, Web of Science, Proquest, Embase, Dentistry and Oral Sciences Source, and ClinicalTrials.gov were systematically searched from inception to May 2023.
STUDY SELECTION
Studies on the association between antibiotic prophylaxis and infective endocarditis following invasive dental procedures or time-trend analyses of infective endocarditis incidence before and after current antibiotic prophylaxis guidelines were included.
DATA EXTRACTION AND SYNTHESIS
Study quality was evaluated using structured tools. Data were extracted by independent observers. A pooled relative risk (RR) of developing infective endocarditis following invasive dental procedures in individuals who were receiving antibiotic prophylaxis vs those who were not was computed by random-effects meta-analysis.
MAIN OUTCOMES AND MEASURES
The outcome of interest was the incidence of infective endocarditis following invasive dental procedures in relation to antibiotic prophylaxis.
RESULTS
Of 11 217 records identified, 30 were included (1 152 345 infective endocarditis cases). Of them, 8 (including 12 substudies) were either case-control/crossover or cohort studies or self-controlled case series, while 22 were time-trend studies; all were of good quality. Eight of the 12 substudies with case-control/crossover, cohort, or self-controlled case series designs performed a formal statistical analysis; 5 supported a protective role of antibiotic prophylaxis, especially among individuals at high risk, while 3 did not. By meta-analysis, antibiotic prophylaxis was associated with a significantly lower risk of infective endocarditis after invasive dental procedures in individuals at high risk (pooled RR, 0.41; 95% CI, 0.29-0.57; P for heterogeneity = .51; I2, 0%). Nineteen of the 22 time-trend studies performed a formal pre-post statistical analysis; 9 found no significant changes in infective endocarditis incidence, 7 demonstrated a significant increase for the overall population or subpopulations (individuals at high and moderate risk, streptococcus-infective endocarditis, and viridans group streptococci-infective endocarditis), whereas 3 found a significant decrease for the overall population and among oral streptococcus-infective endocarditis.
CONCLUSIONS AND RELEVANCE
While results from time-trend studies were inconsistent, data from case-control/crossover, cohort, and self-controlled case series studies showed that use of antibiotic prophylaxis is associated with reduced risk of infective endocarditis following invasive dental procedures in individuals at high risk, while no association was proven for those at low/unknown risk, thereby supporting current American Heart Association and European Society of Cardiology recommendations. Currently, there is insufficient data to support any benefit of antibiotic prophylaxis in individuals at moderate risk.
PubMed: 38581643
DOI: 10.1001/jamacardio.2024.0873 -
Microscopy Research and Technique Aug 2024To incorporate different concentrations of AlOZr (1%, 5%, and 10%) nanoparticles (NP) into the ER adhesive and subsequently assess the impact of this addition on the...
Aluminum zirconate nanoparticles in etch and rinse adhesive to caries affected dentine: An in-vitro scanning electron microscopy, elemental distribution, antibacterial, degree of conversion and micro-tensile bond strength assessment.
To incorporate different concentrations of AlOZr (1%, 5%, and 10%) nanoparticles (NP) into the ER adhesive and subsequently assess the impact of this addition on the degree of conversion, μTBS, and antimicrobial efficacy. The current research involved a wide-ranging examination that merged various investigative techniques, including the application of scanning electron microscopy (SEM) for surface characterization of NP coupled with energy-dispersive x-ray spectroscopy (EDX), Fourier-transform infrared (FTIR) spectroscopy, μTBS testing, and microbial analysis. Teeth were divided into four groups based on the application of modified and unmodified three-step ER adhesive primer. Group 1 (0% AlOZr NPs) Control, Group 2 (1% AlOZr NPs), Group 3 (5% AlOZr NPs), and Group 4 (10% AlO9Zr3 NPs). EDX analysis of AlOZr NPs was performed showing elemental distribution in synthesized NPs. Zirconium (Zr), Aluminum (Al), and Oxides (O). After primer application, an assessment of the survival rate of Streptococcus mutans was completed. The FTIR spectra were analyzed to observe the characteristic peaks indicating the conversion of double bonds, both before and after the curing process, for the adhesive Etch and rinse containing 1,5,10 wt% AlOZr NPs. μTBS and failure mode assessment were performed using a Universal Testing Machine (UTM) and stereomicroscope respectively. The μTBS and S.mutans survival rates comparison among different groups was performed using one-way ANOVA and Tukey post hoc (p = .05). Group 4 (10 wt% AlOZr NPs + ER adhesive) specimens exhibited the minimum survival of S.mutans (0.11 ± 0.02 CFU/mL). Nonetheless, Group 1 (0 wt% AlOZr NPs + ER adhesive) displayed the maximum surviving S.mutans (0.52 ± 0.08 CFU/mL). Moreover, Group 2 (1 wt% AlOZr NPs + ER adhesive) (21.22 ± 0.73 MPa) samples displayed highest μTBS. However, the bond strength was weakest in Group 1 (0 wt% AlOZr NPs + ER adhesive) (14.13 ± 0.32 MPa) study samples. The etch-and-rinse adhesive exhibited enhanced antibacterial activity and micro-tensile bond strength (μTBS) when 1% AlOZr NPs was incorporated, as opposed to the control group. Nevertheless, the incorporation of AlOZr NPs led to a decrease in DC. RESEARCH HIGHLIGHTS: 10 wt% AlOZr NPs + ER adhesive specimens exhibited the minimum survival of S.mutans. 1 wt% AlOZr NPs + ER adhesive samples displayed the most strong composite/CAD bond. The highest DC was observed in Group 1: 0 wt% AlOZr NPs + ER adhesive.
Topics: Zirconium; Microscopy, Electron, Scanning; Streptococcus mutans; Aluminum; Tensile Strength; Anti-Bacterial Agents; Humans; Dentin; Dental Caries; Nanoparticles; Spectroscopy, Fourier Transform Infrared; Dental Cements; Spectrometry, X-Ray Emission; Dental Bonding; Surface Properties; Adhesives
PubMed: 38581370
DOI: 10.1002/jemt.24569 -
BMC Neurology Apr 2024Streptococcus intermedius is a member of the S. anginosus group and is part of the normal oral microbiota. It can cause pyogenic infections in various organs, primarily...
BACKGROUND
Streptococcus intermedius is a member of the S. anginosus group and is part of the normal oral microbiota. It can cause pyogenic infections in various organs, primarily in the head and neck area, including brain abscesses and meningitis. However, ventriculitis due to periodontitis has not been reported previously.
CASE PRESENTATION
A 64-year-old male was admitted to the hospital with a headache, fever and later imbalance, blurred vision, and general slowness. Neurological examination revealed nuchal rigidity and general clumsiness. Meningitis was suspected, and the patient was treated with dexamethasone, ceftriaxone and acyclovir. A brain computer tomography (CT) scan was normal, and cerebrospinal fluid (CSF) Gram staining and bacterial cultures remained negative, so the antibacterial treatment was discontinued. Nine days after admission, the patient's condition deteriorated. The antibacterial treatment was restarted, and a brain magnetic resonance imaging revealed ventriculitis. A subsequent CT scan showed hydrocephalus, so a ventriculostomy was performed. In CSF Gram staining, chains of gram-positive cocci were observed. Bacterial cultures remained negative, but a bacterial PCR detected Streptococcus intermedius. An orthopantomography revealed advanced periodontal destruction in several teeth and periapical abscesses, which were subsequently operated on. The patient was discharged in good condition after one month.
CONCLUSIONS
Poor dental health can lead to life-threatening infections in the central nervous system, even in a completely healthy individual. Primary bacterial ventriculitis is a diagnostic challenge, which may result in delayed treatment and increased mortality.
Topics: Male; Humans; Middle Aged; Streptococcus intermedius; Cerebral Ventriculitis; Anti-Bacterial Agents; Meningitis; Central Nervous System Bacterial Infections; Periodontitis
PubMed: 38580923
DOI: 10.1186/s12883-024-03604-4 -
Indian Journal of Medical Microbiology 2024Viridans Group of Streptococci (VGS) are heterogeneous alpha hemolytic Streptococci that form commensal flora in the oral cavity, upper respiratory tract,...
INTRODUCTION
Viridans Group of Streptococci (VGS) are heterogeneous alpha hemolytic Streptococci that form commensal flora in the oral cavity, upper respiratory tract, gastrointestinal tract and female genital tract and are potential pathogens that can cause serious infections like infective endocarditis and bacteremia. Penicillin or Ceftriaxone is the recommended first line agent for definitive therapy of VGS endocarditis. Alteration in penicillin binding proteins can decrease the susceptibility of VGS to penicillin and other beta-lactam agents and complicate antimicrobial therapy for serious VGS infections like Infective endocarditis. The aim of our study was to determine the antimicrobial susceptibility pattern of viridians group Streptococci isolated from blood samples of infective endocarditis patients from April 2018 to September 2023 against betalactam and other agents.
MATERIAL AND METHODS
Three sets of blood cultures with 8-10 ml per bottle were collected from suspected infective endocarditis and incubated in automated blood culture system (BACTEC from BD diagnostics). The broth from positive bottles was streaked on Blood agar, Chocolate agar and MacConkey agar plates and incubated at 37°C. Alpha hemolytic Streptococci that grew after 24-48 h were further identified and antimicrobial susceptibility determined by Vitek 2 system.
RESULTS
A total of 100 VGS was isolated from blood samples of Infective endocarditis patients. The species most commonly isolated in our study was S. sanguinis (25%) and S.mitis/oralis group (23%) followed by Non speciated Viridans Streptococci (17%). The lowest penicillin susceptibility ie. PEN MIC <0.12 μg/ml of 40% was observed in S. alactolyticus group, followed by S. mitis (52%) and S. gallolyticus (56%). S. mitis/oralis group showed the lowest susceptibilities to betalactam antibiotics among all speciated and non speciated VGS.
CONCLUSION
Infective endocarditis carries a very high mortality and morbidity and the emergence of resistance to betalactam agents like penicillin will only narrow available therapeutic options and further challenge the treatment.
Topics: Humans; Microbial Sensitivity Tests; Viridans Streptococci; Anti-Bacterial Agents; Streptococcal Infections; Female; Endocarditis, Bacterial; Male; Endocarditis; Adult; Middle Aged; Penicillins
PubMed: 38556250
DOI: 10.1016/j.ijmmb.2024.100576 -
Journal of Global Antimicrobial... Jun 2024Eravacycline, a new tetracycline derivative, exhibits broad-spectrum antimicrobial susceptibility. This study aimed to comprehensively investigate in vitro activities of... (Comparative Study)
Comparative Study
OBJECTIVES
Eravacycline, a new tetracycline derivative, exhibits broad-spectrum antimicrobial susceptibility. This study aimed to comprehensively investigate in vitro activities of eravacycline, tigecycline, and ertapenem against various Gram-positive, Gram-negative, and anaerobic bacteria.
METHODS
Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method. The following bacterial species were collected: vancomycin-sensitive (VS) Enterococci species, vancomycin-resistant Enterococci species (VRE), Staphylococcus aureus, Streptococcus anginosus, Bacteroides species, Clostridioides difficile, Clostridium innocuum, Clostridium perfringens, Parabacteroides distasonis, and Stenotrophomonas maltophilia.
RESULTS
We found that eravacycline exhibited superior in vitro activity compared to tigecycline and ertapenem. Notably, it exhibited the lowest MIC for several bacterial species, including VS E. faecalis (0.12 µg/mL), VS E. faecium (0.12 µg/mL), and others. Besides, VRE was susceptible to eravacycline (MIC:0.12 µg/mL) and tigecycline (MIC:0.12 µg/mL), but was all resistant to ertapenem (MIC > 64 µg/mL). S. aureus was also susceptible to eravacycline (MIC:0.5 µg/mL) as well as tigecycline (MIC:1.0 µg/mL). Furthermore, S. anginosus showed higher susceptibility to eravacycline (MIC:2.0 µg/mL) and tigecycline (MIC:4.0 µg/mL), but lower to ertapenem (MIC:32.0 µg/mL). Eravacycline and tigecycline also demonstrated good susceptibility to anaerobes, including Bacteroides species (susceptibility rate: 100%), P. distasonis (100%), C. difficile (94.1‒100%), C. innocuum (94.1‒96.1%), and C. perfringens (88.9‒96.3%). For S. maltophilia, both tigecycline and eravacycline showed an MIC of 2 µg/mL. A moderate-to-strong correlation (rho = 0.608-0.804, P < 0.001) was noted between the MIC values of eravacycline and tigecycline against various bacterial species.
CONCLUSIONS
Our study highlights the potential of eravacycline as an effective treatment option for multidrug-resistant bacterial infections.
Topics: Microbial Sensitivity Tests; Tigecycline; Tetracyclines; Humans; Anti-Bacterial Agents; Bacteria, Anaerobic; Taiwan; Ertapenem; Staphylococcus aureus; Bacteria, Aerobic; Vancomycin-Resistant Enterococci; Streptococcus anginosus; Clostridioides difficile; Stenotrophomonas maltophilia; Vancomycin; Gram-Negative Bacteria; Gram-Positive Bacteria
PubMed: 38552878
DOI: 10.1016/j.jgar.2024.03.014 -
BMC Complementary Medicine and Therapies Mar 2024Natural products are one of the best candidates for controlling drug-resistant pathogens, the advantages of which include low production costs and low side effects. In...
BACKGROUND
Natural products are one of the best candidates for controlling drug-resistant pathogens, the advantages of which include low production costs and low side effects. In this study, as potential antimicrobials, the anti-bacterial and antibiofilm activities of several Iranian native medicinal plants were screened.
METHODS
The antibacterial/antifungal and anti-biofilm activities of 18 medicinal plants including Reseda lutea L., Nepeta sintenisii Bunge., Stachys turcomanica Trautv., Stachys lavandulifolia Vahl, Diarthron antoninae (Pobed.) Kit Tan., Ziziphora clinopodioides Lam., Euphorbia kopetdaghi Prokh, Euphorbia serpens Kunth., Hymenocrater calycinus Benth., Scutellaria pinnatifida A.Ham., Viola tricolor L., Hypericum helianthemoides (Spach) Boiss., Hypericum scabrum L., Convolvulus lineatus L., Scabiosa rotata M.Bieb Greuter & Burdet, Delphinium semibarbatum Bien. Ex Boiss., Glycyrrhiza triphylla Fisch. & C.A.Mey., and Ziziphus jujuba Mill., against two Gram-positive bacteria, Staphylococcus aureus, Bacillus cereus, as well as two Gram-negative bacteria, Pseudomonas aeruginosa, Escherichia coli; and Candida albicans as a fungal strain, were evaluated. The minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) values of the extracts against tested microorganisms were reported and we investigated their effect on the biofilm inhibition of Pseudomonas aeruginosa PAO1, Staphylococcus epidermis, Staphylococcus aureus and Streptococcus mutans. In addition, the effect of the extracts on the eradication of the biofilms of these bacteria was evaluated.
RESULTS
In this study, H. scabrum was found to exhibit potentially significant activity against Gram-positive bacteria with the MIC range of 6.25-25 µg/mL. This extract also showed a significant effect on inhibiting the biofilm of S. aureus, S. mutans, and S. epidermidis and eradicating the biofilm of S. epidermidis DSMZ 3270. In addition, Hymenocrater calycinus root extract had moderate antibacterial activity against B. cereus with the MIC and MBC 62.5 µg/mL, respectively.
CONCLUSIONS
The results of this study showed that the root extracts of two plants, Hypericum scabrum and Hymenocrater calycinus, had antimicrobial and anti-biofilm effects. Based on the observed anti-biofilm effects, these two plants may be considered in future studies to find responsible antimicrobial compounds.
Topics: Plants, Medicinal; Iran; Staphylococcus aureus; Plant Extracts; Anti-Infective Agents; Anti-Bacterial Agents; Biofilms; Candida albicans; Pseudomonas aeruginosa; Streptococcus mutans
PubMed: 38549139
DOI: 10.1186/s12906-024-04437-x -
The Journal of Clinical Pediatric... Mar 2024Fluoridated dentifrices have antibacterial effects on children's teeth. On the other hand, the side effects encountered with the use of them have led researchers to look...
Fluoridated dentifrices have antibacterial effects on children's teeth. On the other hand, the side effects encountered with the use of them have led researchers to look for safe alternatives. This study aimed to determine the antibacterial effect of different commercially available fluoride-free dentifrices on () in comparison with different concentrations of fluoridated dentifrices. Study groups comprised of fluoride-free dentifrices, which contain Probiotic (Activated Charcoal Probiotic Dentifrice-Group P), Aloe Vera-Group AV and Salivary Proteins-Group SP. Fluoridated dentifrices containing 1450 ppm fluoride-Control Group 1 and 500 ppm fluoride-Control Group 2 served as control groups. Antibacterial activity was assessed by Minimum Inhibitory Concentrations and agar well diffusion assays on . Biofilm inhibition assay was performed with dentifrices, which had antibacterial activities, and a negative control phosphate-buffered saline (Group PBS) on sterile hydroxyapatite discs against . Statistical evaluation was performed. Only group AV showed an antibacterial effect on , while control groups showed a similar antibacterial effect. The mean number of viable bacteria present in biofilm in Control Group 1 and 2 and Group AV were statistically significantly lower than that in Group PBS, but there were no statistically significant differences between Control Groups and Group AV. Antibacterial activity of commercial dentifrices against may be exerted by antibacterial components other than fluoride. Aloe vera-containing toothpaste showed an antibacterial effect on , although not as much as the fluoride-containing toothpastes in the control groups. However, further and long-term studies are required.
Topics: Child; Humans; Dentifrices; Fluorides; Streptococcus mutans; Toothpastes; Anti-Bacterial Agents
PubMed: 38548635
DOI: 10.22514/jocpd.2024.035