In vitro activities of antimicrobial agents against Candida species

Are Mouthwashes Really Effective against Candida spp.?

Oral candidiasis is an opportunistic infection caused by fungi of the genus Candida. Nystatin, fluconazole, and miconazole are the most widely used antifungal drugs in dentistry, but in recent years, they have been shown to be less effective due to the increase in the resistance to antifungal drugs. The growing challenge of antifungal resistance emphasizes the importance of exploring not only alternative strategies in the fight against Candida spp. infections but also supportive treatment for pharmacological treatment for oral candidiasis. This review aims to evaluate and compare the in vitro reports on antifungal efficacy against Candida spp. exhibited by mouthwashes distributed on the European market. The research question was elaborated through the PEO framework recommended by PRISMA 2020. A bibliographic search strategy was developed for the scientific online databases Pubmed and ScienceDirect. According to the eligibility criteria, 21 papers were included in this study over a 27-year period. Mouthwashes containing chlorhexidine digluconate, cetylpyridinium chloride, hexetidine, and fluorine compounds among others, and natural antimicrobials, such as menthol, thymol, eucalyptol, and Glycyrrhiza glabra extracts, have demonstrated antifungal effectiveness. Nonetheless, the methodological variance introduces ambiguity concerning the comparative efficacy of distinct molecules or mouthwash formulations and complicates the evaluation and the comparison of results between studies. Some mouthwashes commercially available in Europe have the potential to be used in anti-Candida therapy and prevention since they have shown antifungal effect.

Antimicrobial Efficacy of Probiotic and Herbal Oral Rinses against Candida albicans in Children: A Randomized Clinical Trial

Background: A growing number of dentists are embracing the philosophy that natural agents are better for children’s oral health. Knowledge of probiotics on host immune system has entered a new phase of research, and progression in this field is likely to offer novel means by modulating host immunity for prevention and treatment of a wide variety of oral diseases.

Aim: To compare the antimicrobial efficacy of probiotics in reducing salivary Candida albicans counts with commonly used antimicrobial agents like 0.2% chlorhexidine and herbal rinse.

Materials and methods: A randomized clinical trial was conducted on 60 subjects aged between 6 and 14 years, for a period of 9 months. The subjects were randomly divided into three groups comprising 20 subjects in each group. Three oral agents were administered twice daily for a maximum period of 1 week. Candida albicans counts were recorded before and after intervention and the results were submitted for statistical analysis using Statistical Package for the Social Sciences (SPSS) version 15.0 software.

Results: The change in mean log₁₀ colony-forming unit (CFU)/ ml of C. albicans in groups A to C was 0.43 ± 0.72, 0.68 ± 1.05 and 0.22 ± 0.66 CFU/ml respectively.

Conclusion: Data obtained from the study demonstrated that probiotic rinse was equally effective as 0.2% chlorhexidine digluconate rinse in reducing C. albicans counts after 1 week of intervention. Herbal oral rinse was least effective. Probiotic oral rinses have opened new horizons in improvement of oral health by maintaining healthy ecosystem. However, a longitudinal study with larger sample size needs to be undertaken to evaluate the therapeutic effects of probiotics and herbal agents.

How to cite this article: Mishra R, Tandon S, Rathore M, Banerjee M. Antimicrobial Efficacy of Probiotic and Herbal Oral Rinses against Candida albicans in Children: A Randomized Clinical Trial. Int J Clin Pediatr Dent 2016;9(1):25-30.

Antifungal prescribing pattern and attitude towards the treatment of oral candidiasis among dentists in Jordan

AIM

The aim of this study was to evaluate the attitude of Jordanian dentists towards the treatment of oral candidiasis and their current antifungal prescribing habits, shedding more light on the possible influence of their socio-professional factors on the pattern of prescribing and practice.

METHODS

A structured validated questionnaire was developed and tested; it was then emailed to a random sample of 600 Jordanian dental practitioners during the period of this cross-sectional survey. The questionnaire recorded practitioners' personal details and their attitude and prescribing of antifungal therapy for oral candidiasis. Statistical significance was based on probability values of <0.05 and was measured using the chi-square and Fisher's exact tests. Multiple logistic regression analysis was used to analyse the influence of respondents' socio-professional factors on their attitude towards oral candidiasis.

RESULTS

Of the 423 questionnaires returned, only 330 were included. The attitude of respondents was significantly influenced by their experience [odds ratio (OR) = 0.14; P < 0.001] and workplace (OR = 4.70; P < 0.001). Nystatin was the most commonly prescribed antifungal agent (78.2%), followed by miconazole (62.4%), which was prescribed for topical use. Systemic antifungals were prescribed by 21.2% of respondents, with a significant (P < 0.05) association with the country in which their qualification was obtained.

CONCLUSION

The attitude towards the treatment of oral candidiasis is much better among the least-experienced dentists working in private practice. Nystatin and miconazole are the most popular choices of antifungal agents among Jordanian dentists.

Chlorhexidine: beta-cyclodextrin inhibits yeast growth by extraction of ergosterol

Chlorhexidine (Cx) augmented with beta-cyclodextrin (β-cd) inclusion compounds, termed Cx:β-cd complexes, have been developed for use as antiseptic agents. The aim of this study was to examine the interactions of Cx:β-cd complexes, prepared at different molecular ratios, with sterol and yeast membranes. The Minimal Inhibitory Concentration (MIC) against the yeast Candida albicans (C.a.) was determined for each complex; the MICs were found to range from 0.5 to 2 μg/mL. To confirm the MIC data, quantitative analysis of viable cells was performed using trypan blue staining. Mechanistic characterization of the interactions that the Cx:β-cd complexes have with the yeast membrane and assessment of membrane morphology following exposure to Cx:β-cd complexes were performed using Sterol Quantification Method analysis (SQM) and scanning electron microscopy (SEM). SQM revealed that sterol extraction increased with increasing β-cd concentrations (1.71 ×10³; 1.4 ×10³; 3.45 ×10³, and 3.74 ×10³ CFU for 1:1, 1:2, 1:3, and 1:4, respectively), likely as a consequence of membrane ergosterol solubilization. SEM images demonstrated that cell membrane damage is a visible and significant mechanism that contributes to the antimicrobial effects of Cx:β-cd complexes. Cell disorganization increased significantly as the proportion of β-cyclodextrin present in the complex increased. Morphology of cells exposed to complexes with 1:3 and 1:4 molar ratios of Cx:β-cd were observed to have large aggregates mixed with yeast remains, representing more membrane disruption than that observed in cells treated with Cx alone. In conclusion, nanoaggregates of Cx:β-cd complexes block yeast growth via ergosterol extraction, permeabilizing the membrane by creating cluster-like structures within the cell membrane, possibly due to high amounts of hydrogen bonding.

Susceptibilities of Candida albicans mouth isolates to antifungal agents, essentials oils and mouth rinses

Forty Candida albicans strains isolated from patient's mouth with fixed orthodontic appliances were analyzed to their susceptibilities to antifungal agents, mouth rinses and essential oils. Susceptibility to fluconazole, econazole, miconazole and ketoconazole, amphotericin B and nystatin was assessed by the disk diffusion (DD) method based on the Clinical and Laboratory Standards Institute M44-A protocol, and by Etest (fluconazole and amphotericin B). The susceptibilities to mouth rinses and essential oils were also determined by the DD technique. All isolates tested were susceptible (S) to amphotericin B, nystatin and fluconazole. The overall concordance between the DD and the Etest was 100% for amphotericin and fluconazole. One isolate was resistant to econazole (2.5%) and the other to ketoconazole (2.5%). Econazole and ketoconazole had the highest percentages of susceptible dose dependent (SDD), 55 and 95%, respectively. Regarding to the susceptibility isolates profile, seven phenotypes were detected, and the 3 more represented (90% of the isolates) of them were SDD to one, two or three azoles. The study of mouth rinses showed a high variability of efficacy against C. albicans. The results showed that the isolates susceptibility to essential oils differed (P < 0.05). The profile activity was: cinnamon > laurel > mint > eucalyptus > rosemary > lemon > myrrh > tangerine. The main finding was that the susceptibility to cinnamon and laurel varied among the three more representative antifungal phenotypes (P < 0.05). The susceptibility of econazole-SDD isolates to cinnamon and lemon was higher than those of the econazole-S yeasts (P < 0.05). In contrast, econazole-SDD isolates were less affected by laurel than econazole-S counterparts (P < 0.05).

Histological Evaluation of Peri-Implant Soft Tissues in Immediately Loaded Implants Featuring Different Implant-Abutment Connections: A Preliminary Study

The aim of the present study is to evaluate the peri-implant soft tissues and the amount of inflammatory cells around two different implant-abutment connections (self-locking conical connection with platform switching and screwed connection with standard abutment and internal anti-rotational system). Histological analysis was made of 14 implants, 7 with self-locking Morse tapered connection (experimental group A) and 7 with screw-retained anti-rotational connection (control group B). Sixty days after non-functional immediate loading, peri-implant tissue biopsies were performed. In the samples taken from the experimental group the peri-implant connective tissue consisted of a greater density of collagen and fibroblasts compared to the connective tissue of the control group. The experimental group specimens showed less inflammatory infiltrate close to the self-locking tapered connection compared to the tissues around the screw-retained connection. The SEM observations showed less microgap in the self-locking conical connection than in the screw connections with standard abutment and internal anti-rotational system. The presence of connective tissue with few inflammatory cells and the absence of inflammatory infiltrate, in self-locking conical connection implants is due to the minimal size of the implant-abutment microgap that does not allow the passage of fluids and bacteria from the oral cavity to the implant thus preventing tissue inflammation.

Oral health promotion interventions on oral yeast in hospitalised and medically compromised patients: a systematic review

Yeast are major aetiological agents of localised oral mucosal lesions, and are also leading causes of nosocomial bloodstream infections. The purpose of this systematic review was to examine the effectiveness of oral health promotion interventions on the prevalence and incidence of these opportunistic oral pathogens in hospitalised and medically compromised patients. The PubMed, ISI Web of Science and Cochrane Library databases were searched for clinical trials assessing the effect of oral health promotion interventions on oral yeast. Chlorhexidine delivered in a variety of oral hygiene products appeared to have some effect on oral yeast, although some studies found equivocal effects. Although a wide array of other compounds have also been investigated, their clinical effectiveness remains to be substantiated. Likewise, the utility of mechanical oral hygiene interventions and other oral health promotion measures such as topical application of salivary substitute, remains unsettled. Although many chemical agents contained in oral hygiene products have proven in vitro activity against oral yeast, their clinical effectiveness and potential role as adjuncts or alternative therapies to conventional treatment remains to be confirmed by further high-quality randomised controlled trials. This is pertinent, given the recent emergence of yeast resistance to conventional antifungal agents.

Use of antifungal agents for oral candidiasis: results of a national survey

BACKGROUND

Candida albicans is an opportunistic agent that colonizes the oral mucosa.

OBJECTIVES

To determine the attitude of Spanish dentists toward the oral treatment of candidiasis.

METHOD

Between May and November 2006, a questionnaire was circulated to a random selection of 1134 dentists obtained from the General Dental Council's main list. The survey consisted of a block of socio-demographic items followed by another block related to the diagnosis and treatment of oral candidiasis. Replies to the questionnaire were received from 840 (74%) dentists.

RESULTS

50.4% of respondents were men, and 48.1% were female with a mean age of 38 and 12.2 years of professional experience. Miconazole was the most popular choice of antifungal agent prescribed (59.3%), followed by nystatin (57.7%) for topical use. Systemic antifungal agents were used by 30.20% of dentists, with a strong association between their use and the number of years in practice, gender and professional qualifications (P < 0.005).

CONCLUSION

Most Spanish dentists make clinical diagnosis and treat oral infections by C. albicans themselves with topical drugs (miconazole and nystatin) as a first choice. Systemic treatments are more commonly chosen by male dentists with long professional experience, especially by stomatologists.

Sensitivity of Candida albicans biofilm cells grown on denture acrylic to antifungal proteins and chlorhexidine

OBJECTIVES

Candida albicans cells form biofilms on polymeric surfaces of dentures and other prostheses introduced into the oral cavity. Many biofilm microorganisms exhibit resistance to antimicrobial agents; C. albicans cells may also develop resistance to naturally occurring antifungal peptides in human saliva including histatins (Hsts) and defensins (hBDs). Therefore, we evaluated Hst 5 activity on C. albicans biofilm cells compared to planktonic cells and measured whether surface treatment of denture acrylic with Hst 5, hBD-3, or chlorhexidine gluconate could inhibit in vitro biofilm development.

METHODS

Acrylic disks were preconditioned with 500 microl saliva for 30 min, and inoculated with C. albicans cells (10(6)cells/ml) for 1h, at 37 degrees C. Non-adherent cells were removed by washing and disks and were incubated in YPD growth medium for 24, 48, and 72 h at 37 degrees C. Candidacidal assays were performed on 48-h-biofilms and on planktonically grown cells using Hst 5 (15.5, 31.25, and 62 microM). Cell adhesion was compared on disks pre-coated with 0.12% chlorhexidine gluconate, 50 microM Hst 5, or 0.6 microM hBD-3 after 24, 48, and 72 h growth.

RESULTS

No significant difference was observed in sensitivity to Hst 5 of biofilm cells compared to planktonic cells (p>0.05). Pre-coating disks with hBD-3 did not inhibit biofilm development; however, Hst 5 significantly inhibited biofilm development at 72 h, while 0.12% chlorhexidine significantly inhibited biofilm development at all time intervals (p<0.05).

CONCLUSIONS

C. albicans biofilm cells grown on denture acrylic are sensitive to killing by Hst 5. Surface coating acrylic with chlorhexidine or Hst 5 effectively inhibits biofilm growth and has potential therapeutic application.

Antifungal effect of mouth rinses on oral Candida counts and salivary flow in treatment-naïve HIV-infected patients

Oral candidiasis is a major problem in developing countries where antiretroviral therapy is available to a small percentage of the infected population. HIV patients are prone to xerostomia and predisposed to Candida infection. Preventing oral candidiasis is better than the frequent use of antifungals that may lead to the development of drug resistance. This study investigated the ability of commercial mouth rinses and sodium bicarbonate to reduce salivary Candida and to improve the saliva flow of HIV-positive patients. One hundred fifty HIV patients without oral candidiasis were examined for oral lesions initially and after 2, 4, and 12 weeks. Unstimulated saliva was collected; the volume was measured and cultured for yeasts. Subjects were provided with mouth rinses containing either benzydamine hydrochloride, benzydamine hydrochloride with chlorhexidine gluconate, triclosan with sodium fluoride, 5% sodium bicarbonate, or placebo and asked to rinse twice daily for 12 weeks. The effect of the mouth rinses and placebo on Candida counts and saliva flow was analyzed using analysis of variance (ANOVA). A total of 108 patients completed the trial, 35 missed appointments, 4 died, 2 developed oral candidiasis, and 1 herpetic lesion. Triclosan/fluoride decreased the Candida count more than the placebo (p = 0.005) while chlorhexidine/benzydamine hydrochloride (p = 0.001) and triclosan/fluoride mouthrinses (p = 0.002) increased the salivary flow during the initial 4 weeks. The most effective mouth rinse triclosan/fluoride decreased oral Candida counts and increased saliva flow. Studies are needed to determine the efficacy of these mouth rinses for the long-term prevention of clinical oral candidiasis in adult HIV-positive patients.

Antifungal activity of the plant Dodonaea viscosa var. angustifolia on Candida albicans from HIV-infected patients

was to determine the minimum inhibitory concentration (MIC) and the time taken by Dodonaea viscosa var. angustifolia (PLE) a South African medicinal plant, chlorhexidine gluconate (CHX) and triclosan (TRN) to kill Candida albicans. 41 strains of Candida albicans were investigated, 20 from HIV-positive patients, 20 from HIV-negative subjects and Candida albicans ATCC 90028. The MICs of an acetone extract of PLE, CHX and TRN were measured using a microtitre double dilution technique, and the time taken to kill 99.5% of the strains was determined. The MICs of PLE, CHX and TRN were 6.25-25, 0.008-0.16 and 0.0022-0.009 mg/ml, respectively. PLE killed all the test strains within 30s and CHX 40% of the isolates from HIV-positive patients and 20% of strains from HIV-negative subjects in 1 min. During the same time TRN killed 55% and 35% of isolates from HIV-positive and HIV-negative patients. Dodonaea viscosa var. angustifolia has antifungal properties and is more effective than commercially available mouthrinses.

Management of patients who have undergone head and neck cancer therapy

Patients who undergo treatment for head and neck cancers often suffer from acute or late reactions to therapy. Severity of these oral complications may be based on the location and extent of tumor, as well as the type and extent of treatment. Some complications are transient, whereas others require a lifetime of management secondary to damage that results in permanent dysfunction. Patients who have a history of head and neck cancers are also at an increased risk for recurrences or second malignancies, and therefore require close follow-up. Dental professionals should provide preventive and supportive care, including education and symptom management, for patients experiencing oral complications related to cancer therapy, and should closely monitor patients' level of distress, ability to cope, and treatment response.

A prospective randomized trial to reduce oral Candida spp. colonization in patients with hyposalivation

Low salivary flow rates are associated with higher oral Candida spp. counts, which may predispose to oral candidiasis. The aim of this study was to compare the effect of stimulating salivary flow rates with that of a regimen of chlorhexidine mouth rinse on the intensity of Candida colonization in patients with reduced salivary flow rates. Thirty-one outpatients were randomized to stimulate salivary output (group 1) or to receive chlorhexidine mouth rinses (group 2). Evaluations were performed at baseline (T0), at end of treatment (T1), and 15 days after last day of treatment (T2). Chewing-stimulated whole saliva samples were collected at each visit. Group 1 showed a constant reduction in median cfu counts, although the difference was significant only between T0 and T2 (p = 0.004). Group 2 showed a reduction in median Candida cfu counts between T0 and T1 (p = 0.01), but the counts increased at T2 (p = 0.01), and the difference between T0 and T2 was not significant (p = 0.8). In conclusion, patients who received salivary stimulation showed reductions of Candida cfu counts in saliva and a trend for increasing salivary flow rates between baseline and end of study evaluations. The use of chlorhexidine mouth rinses dramatically reduced Candida cfu counts, but when patients discontinued treatment, intensity of colonization rose again.

Effects of cetylpyridinium chloride resistance and treatment on fluconazole activity versus Candida albicans

Mouthwash antiseptic cetylpyridinium chloride (CPC) has potent activity against Candida albicans; however, two of five azole-resistant strains showed reduced CPC susceptibility. To further examine the potential for cross-resistance, CPC-resistant mutants were selected in vitro and their fluconazole susceptibility was tested. MICs were unchanged, and trailing growth generally decreased. With CPC-fluconazole combinations, both antagonism and synergism were observed, which can be explained, in part, by CDR1-CDR2 multidrug transporter upregulation.

Patterns of antifungal prescribing in general dental practice

OBJECTIVE

To examine the current practice of antifungal prescribing by GDPs in the United Kingdom. Design A postal questionnaire circulated to a random selection of 400 dentists.

OUTCOME MEASURES

The questionnaires were analysed and the responses expressed as absolute and relative frequencies.

RESULTS

Responses to the questionnaire were received from 297 (74.3%) GDPs. Nystatin was the most popular choice of antifungal agent that GDPs would use, followed by miconazole, amphotericin B and fluconazole. The likelihood of use of miconazole was positively linked to recent date of graduation. Lack of knowledge regarding contraindications and problems with azole antibiotics was found in a significant minority of practitioners (36%).

CONCLUSIONS

The present study indicates that azole antifungal agents (especially miconazole) are becoming more widely used by GDPs, but that knowledge regarding potential problems with their use is sub-optimal. Nystatin remains the most popular choice of antifungal agent.

Quantitative liquid chromatographic determination of sanguinarine in cell culture medium and in rat urine and plasma

Sanguinarine is a quaternary benzo[c]phenanthridine alkaloid, extracted from the argemone oil, which produced severe human intoxications. To investigate the sanguinarine biotransformation, we develop a simple extraction process and a high performance liquid chromatographic separation coupled to a sensitive fluorometric detection of sanguinarine in cell culture medium, as well as in rat urine and plasma. After extraction with an acidified organic solvent, sanguinarine elution is performed within 15 min on a Nucleosil C18 column with a gradient using 0.2% formic acid/water/acetonitrile as mobile phase. Extracted and standard sanguinarine are characterized by mass spectrometry. The extraction recovery of sanguinarine is about 80% in cell culture medium and in rat urine, but lower in plasma. This convenient high performance liquid chromatography (HPLC) method allows to quantify sanguinarine over concentrations ranged 10-2000 ng ml(-1). The limit of fluorometric detection is 0.5 ng. Under these conditions, the lower limit of quantification of sanguinarine is 50 ng ml(-1) in cell culture medium and in rat urine and 100 ng ml(-1) in rat plasma. This analytical HPLC method is specific, linear and reproducible in all media and is suitable for quantitative determination of sanguinarine in biological fluids.

In vitro effect of sanguinarine alkaloid on binding of [3H]candesartan to the human angiotensin AT1 receptor

The type of interaction of 5-methyl-2,3,7,8-bis(methylenedioxy)benzo[c]phenanthridinium (sanguinarine), an alkaloid isolated from the root of Bocconia frutescens L., with the human angiotensin AT(1) receptor was evaluated in both intact cells and membrane binding of [3H](2-ethoxy-1-[(2'-(1H-tetrazol-5-yl)biphenyl-4-yl)methyl]-1H-benzimidazoline-7-carboxylic acid) ([3H]candesartan). The results indicate that the inhibition of [3H]candesartan binding by sanguinarine is independent of cell viability, since the alkaloid inhibited at a similar extent radioligand binding on both intact Chinese hamster ovary (CHO) cells transfected with the human angiotensin AT(1) receptor (hAT(1)) and their cell membranes (K(i)=0.14 and 1.10 microM, respectively). The unsuccessful recovery of [3H]candesartan binding after washing sanguinarine off the cells suggested a nearly irreversible or slow reversible interaction. Saturation binding studies showed a substantial reduction of the B(max) without affecting the K(d). In addition, the presence of 2-n-butyl-4chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl)biphenyl-4-yl)methyl]imidazole (losartan) could not prevent sanguinarine inhibition of [3H]candesartan binding neither. The present findings indicate that sanguinarine interacts with the receptor in a slow, nearly irreversible and noncompetitive manner.

Periodontal management of patients with cardiovascular diseases

Periodontists are often called upon to provide periodontal therapy for patients with a variety of cardiovascular diseases. Safe and effective periodontal treatment requires a general understanding of the underlying cardiovascular diseases, their medical management, and necessary modifications to dental/periodontal therapy that may be required. In this informational paper more common cardiovascular disorders will be discussed and dental management considerations briefly described. This paper is intended for the use of periodontists and members of the dental profession.

Antifungal and antiviral chemotherapy

Fungal and viral infections are difficult to treat, since fungal infections commonly rebound after suppression by the antifungal agent and current antiviral drugs are only virustatic, allowing the virus to reassert its pathogenicity if not eliminated by the host defenses. In addition, fungal infections commonly are associated with significant biofilms, retarding drug penetration, and the fluid nature of the oral cavity does not promote drug-fungus contact for long periods of time. Both mycotic and viral pathogens are developing sophisticated methods to elude the toxic effects of drugs intended to eliminate their existence. The drug therapy of oral fungal and viral infections is therefore limited but occasionally successful (more with fungal than viral infections) and is often relegated to palliative care. The specter of drug resistance and its promotion by prolonged, repetitive and frivolous use must always be foremost in the clinician's mind.

In vitro studies of the efficacy of antimicrobials against fungi

OBJECTIVE

The purpose of this study was to compare the efficacy of Listerine Antiseptic, Tartar Control Listerine Antiseptic, and Peridex mouthrinses and a 0.2% chlorhexidine digluconate solution against known pathogenic fungi.

STUDY DESIGN

Standardized methods were used to compare the antimicrobial efficacy of the above agents versus representative fungal species. Minimum inhibitory concentration-minimum fungicidal concentrations in macrobroth dilutions, suspension kill-time, and effectiveness against an artificial biofilm-attached population were studied.

RESULTS

All antimicrobials tested were effective against the fungal species under investigation at the concentration available commercially. Listerine Antiseptic showed a greater efficacy against attached artificial biofilm populations than the other antimicrobials tested.

CONCLUSIONS

Listerine Antiseptic, Tartar Control Listerine Antiseptic, and Peridex mouthrinses show promise as a means to control the pathogenic fungal species under investigation and may have applications to reduce oral colonization.