The most prevalent and worldwide oral disease is dental caries that affects a significant proportion of the world population. There are some classical approaches for control, prevention and treatment of this pathologic condition; however, the results are still not completely successful. Therefore new methods are needed for better management of this important challenge. Chitosan is a natural and non-toxic polysaccharide with many biological applications, particularly as an antimicrobial agent. Chitosan nanoparticle is a bioactive and environment friendly material with unique physicochemical properties. The aim of the present study was to investigate the antimicrobial effect of chitosan and nano-chitosan on the most important cariogenic streptococci. For evaluation of antimicrobial effect of chitosan and nano-chitosan against oral streptococci broth micro-dilution method was carried out for four bacterial species; Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguis and Streptococcus salivarius. Also the effect of these materials on adhesion of above bacteria was evaluated. One-way ANOVA and post hoc Tukey test were used for statistical analysis. The MICs of chitosan for S. mutans, S. sanguis, S. salivarius and S. sobrinus were 1.25, 1.25, 0.625 and 0.625 mg/mL, respectively. The MIC of chitosan nanoparticle for S. mutans, S. salivarius and S. sobrinus was 0.625 mg/mL and for S. sanguis was 0.312 mg/mL. Chitosan and chitosan nanoparticles at a concentration of 5 mg/mL also reduced biofilm formation of S. mutans up to 92.5% and 93.4%, respectively. The results of this study supported the use of chitosan and chitosan nanoparticles as antimicrobial agents against cariogenic Streptococci.

The Masjed-e Jāme’ of Isfahan is one of the largest historic mosques in the Islamic world. It was listed as a World Heritage Site by UNESCO. Due to the arid climate of the region, the building is quite well preserved and presents only localized patterns of alteration. However, due to the risk of biodeteriogenic microorganisms which could be present on these valuable surfaces, this study aimed to isolate the microorganisms associated with the specific deteriorated areas of this monument and determine their deteriorative mechanism. Samples were taken from the deteriorated areas in order to isolate bacteria and fungi. These were tested for their potential to induce biodeterioration via CaCO₃ dissolution, pH alteration, and pigment and mineral production. Results revealed that ubiquitous species such as Penicillium spp. and Bacillus spp. were the most abundant microorganisms isolated from the samples, some of which were able to release organic acids and induce CaCO₃ dissolution. Very often, the isolated fungi showed a combined biodeteriogenic activity due to solubilization and precipitation of CaCO₃. Rarely was CaCO₃ solubilization combined with pigment release. These findings are a first step toward providing helpful information to assess the biodeteriogenic potential of colonizing microorganisms and planning a preventive method for the conservation of this monument which has never been studied in terms of biodeterioration risk.

Objective: The increasing prevalence of Candida infections and the emergence of resistance to chemical antifungal medicines, such as fluconazole, has prompted increased research into natural compounds with anti-Candida activity. Probiotics, in particular, are being investigated as promising alternatives due to their lower costs and reduced side effects compared to synthetic ...

Background and Objectives: Infectious diseases are among the most known important causes of morbidity and mortality in the world. The ongoing explosion antibiotic-resistant bacteria and side effects of medications, application of assistive methods including the use of medicinal plants for treatment have become particularly important. Materials and Methods: In this study, the ethanol extract of green tea (Camellia sinensis) and yarrow flower (Achillea millefolium) were prepared by maceration method and its antibacterial effect on four clinical strains of antibiotic resistant bacteria including Klebsiella pneumoniae, Acinetobacter, Escherichia coli and Pseudomonas aeruginosa were evaluated with microtiter plate method for determining the MIC (Minimum Inhibitory Concentration). Results: The MICs of green tea extract for Acinetobacter baumannii was 15.6 mg/ml and 31.25 mg/ml for Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli. The MIC of Achillea millefolium extract for Acinetobacter baumannii and Escherichia coli was 125 mg/ml and against Klebsiella pneumoniae and Pseudomonas aeruginosa was 250 mg/ml. Conclusion: Considering the antimicrobial effects of green tea and Achillea on four strains of resistant bacteria, the extract of this plant can be used in control and treatment of infections caused by these infectious agents.

Introduction: Increasing antibiotic resistance in microorganisms and the advantages that natural compounds have over synthetic chemicals led to more investigation of plant resources. Rosa damascena is one of the valuable species of the Rosaceae family that has different therapeutic effects. This review studies the antimicrobial effects of R. damascene and ...