In vitro susceptibility of oral Candida to seven antifungal agents

Antimicrobial Activity of Olive Leaf Extract to Oral Candida Isolates

OBJECTIVES

The aim of this study was to determine the antifungal activity of olive leaf extract (OLE) and the synergistic effect of standard antifungal therapy and OLE against clinical oral Candida species' isolates.

MATERIALS AND METHOD

The susceptibility of 60 clinical isolates of the Candida species (36 C. albicans, 16 C. krusei, 5 C. glabrata and 3 C. tropicalis) was tested with four concentrations of OLE (60 µg/µL, 120 µg/µL, 240 µg/µL and 333 µg/µL) and the synergistic effect of standard antifungal therapy and OLE (miconazole (MIC) + 333 µg/µL OLE and nystatin (NYS) + 333 µg/µL OLE). The antimicrobial activity was tested using the disk diffusion method.

RESULTS

All concentrations (60 µg/µL, 120 µg/µL, 240 µg/µL and 333 µg/µL) of OLE showed a statistically significant effect on all Candida species compared to the control (DMSO) except for the lowest concentration (60 µg/µL) tested on C. glabrata. There was a dose-dependent effect of OLE on tested samples. Concentrations of 240 µg/µL and 333 µg/µL showed statistically significant higher antifungal activity compared to the lowest concentration of 60 µg/µL. No statistically significant synergistic effect of OLE and standard antifungal therapy was found compared with standard therapy alone.

CONCLUSIONS

The results of this study present the significant antimicrobial effect of OLE against all tested Candida species except for the lowest concentration on C. glabrata. Increasing the concentration of OLE also increases its effect on Candida species. This indicates the possible potential effect of OLE in the treatment of Candida-related oral diseases.

Antifungal Susceptibility of Oral Candida Isolates from Mother-Infant Dyads to Nystatin, Fluconazole, and Caspofungin

The carriage of Candida albicans in children's oral cavities is associated with a higher risk for early childhood caries, so controlling this fungus in early life is essential for preventing caries. In a prospective cohort of 41 mothers and their children from 0 to 2 years of age, this study addressed four main objectives: (1) Evaluate in vitro the antifungal agent susceptibility of oral Candida isolates from the mother-child cohort; (2) compare Candida susceptibility between isolates from the mothers and children; (3) assess longitudinal changes in the susceptibility of the isolates collected between 0 and 2 years; and (4) detect mutations in C. albicans antifungal resistance genes. Susceptibility to antifungal medications was tested by in vitro broth microdilution and expressed as the minimal inhibitory concentration (MIC). C. albicans clinical isolates were sequenced by whole genome sequencing, and the genes related to antifungal resistance, ERG3, ERG11, CDR1, CDR2, MDR1, and FKS1, were assessed. Four Candida spp. (n = 126) were isolated: C. albicans, C. parapsilosis, C. dubliniensis, and C. lusitaniae. Caspofungin was the most active drug for oral Candida, followed by fluconazole and nystatin. Two missense mutations in the CDR2 gene were shared among C. albicans isolates resistant to nystatin. Most of the children's C. albicans isolates had MIC values similar to those from their mothers, and 70% remained stable on antifungal medications from 0 to 2 years. For caspofungin, 29% of the children's isolates showed an increase in MIC values from 0 to 2 years. Results of the longitudinal cohort indicated that clinically used oral nystatin was ineffective in reducing the carriage of C. albicans in children; novel antifungal regimens in infants are needed for better oral yeast control.

Mechanisms of Action of the Antimicrobial Peptide Cecropin in the Killing of Candida albicans

The development of drug resistance has caused fungal infections to become a global health concern. Antimicrobial peptides (AMPs) offer a viable solution to these pathogens due to their resistance to drug resistance and their diverse mechanisms of actions, which include direct killing and immunomodulatory properties. The peptide Cecropin, which is expressed by genetically engineered bacteria, has antifungal effects on Candida albicans. The minimal inhibitory concentration (MIC) and the minimal fungicidal concentration (MFC) of Candida albicans were 0.9 μg/mL and 1.8 μg/mL, respectively, detected by the micro-broth dilution method. According to the killing kinetics, the MFC of Cecropin could kill Candida albicans in 40 min. The electron microscope indicated that Cecropin could cause the cell wall to become rough and nicked, eventually killing Candida albicans. The effects of Cecropin on the cell membrane of treated C. albicans, using the 1,6-diphenyl-1,3,5-hexatriene and propidium iodide protocol, showed that they could change the permeability and fluidity, destroy it, and lead to cell necrosis. In addition, Cecropin can also induce cells to produce excessive reactive oxygen species, causing changes in the mitochondrial membrane potential. Therefore, this study provides a certain theoretical basis for the antifungal infection of new antifungal agents.

In vitro Azole antifungals susceptibility of Candida spp. isolates from HIV-infected patients with periodontitis

OBJECTIVE

The objective of the present study was to determine the in vitro Azole antifungals susceptibility of Candida spp. strains isolated from HIV-positive patients with periodontitis.

METHODS

Oral examination was performed in 500 HIV-positive patients, of which 228 were included in the study for having periodontitis which and separated in two groups based on their TCD4+ T-cells: (A) n = 110 (≤200 CD4+); (B) n = 118 (>200 CD4+). Candida spp. were isolated from the subgingival biofilm and crevicular fluid by seeding on CHROMagar plates and confirmed by endpoint PCR and MALDI-TOF. The susceptibility test in vitro for five antifungals was performed using the disc diffusion method.

RESULTS

From the 228 HIV-positive patients with periodontitis, 174 were positive to Candida spp., and 204 isolations were obtained. 138 (67.64%) were C. albicans, and 66 (32.35%) were Candida non-albicans species. The most frequent Candida non-albicans species in order of frequency were C. glabrata with 48 (23.52%), C. tropicalis with 10 (4.9%), C. krusei with 7 (3.43%), and C. dubliniensis with 1 (0.49%). All species presented resistance to any antifungal: 149 to 5-fluorocytosine (73.0%), 149 to fluconazole (73.0%), and 144 to voriconazole (70.7%). Miconazole and econazole presented the highest susceptibility rates with 129 (63.2%) and 130 (63.7%) isolations, respectively.

CONCLUSION

The Candida spp. involved in periodontitis of HIV-positive patients have a multi-resistant feature. It is necessary to implement recurrent research regarding the antifungal resistance of the Candida spp. that take part in periodontitis pathogenesis to promote an effective treatment in HIV patients.

The antifungal and antibiofilm activity of Cymbopogon nardus essential oil and citronellal on clinical strains of Candida albicans

OBJECTIVE

This study investigated the antifungal and antibiofilm activity of Cymbopogon nardus essential oil (EO) and its major compound, citronellal, in association with miconazole and chlorhexidine on clinical strains of Candida albicans. The likely mechanism(s) of action of C. nardus EO and citronellal was further determined.

MATERIALS AND METHODS

The EO was chemically characterized by gas chromatography coupled with mass spectrometry (GC-MS). The antifungal activity (MIC/MFC) and antibiofilm effects of C. nardus EO and citronellal were determined by the microdilution method, and their likely mechanism(s) of action was determined by the sorbitol and ergosterol assays. Then, the samples were tested for a potential association with standard drugs through the checkerboard technique. Miconazole and chlorhexidine were used as positive controls and the assays were performed in triplicate.

RESULTS

The GC-MS analysis tentatively identified citronellal as the major compound in C. nardus EO. Both samples showed antifungal activity, with MIC of 256 µg/mL, as compared to 128 µg/mL and 8 µg/mL of miconazole and chlorhexidine, respectively. C. nardus EO and citronellal effectively inhibited biofilm formation (p < 0.05) and disrupted preformed biofilms (p < 0.0001). They most likely interact with the cell membrane, but not the cell wall, and did not present any synergistic activity when associated with standard drugs.

CONCLUSION

C. nardus EO and citronellal showed strong in vitro antifungal and antibiofilm activity on C. albicans.

CLINICAL RELEVANCE

Natural products have been historically bioprospected for novel solutions to control fungal biofilms. Our data provide relevant insights into the potential of C. nardus EO and citronellal for further clinical testing. However, additional bioavailability and toxicity studies must be carried out before these products can be used for the chemical control of oral biofilms.

Inhibitory effects of different fractions separated from standardized extract of Myrtus communis L. against nystatin-susceptible and nystatin-resistant Candida albicans isolated from HIV positive patients

Background

and Purpose: Myrtle (Myrtus communis L.) is a medicinal herb that plays an essential role in treating fungal infections. The present study investigated the antifungal properties of different fractions of the M. communis L. leaf extract against Candida albicans (susceptible and resistant to nystatin).

Materials and methods

Total extract (TE) and petroleum ether (PE), chloroform (CH), ethyl acetate (EA), and methanol (ME) fractions were prepared using the sonication method. The study used the standard strain sample (ATCC 76645) and nystatin-resistant C. albicans from oral samples of HIV-infected individuals. The identification of resistant isolate was performed using phenotypic and molecular methods. Minimum inhibitory concentration (MIC) and Minimum fungicidal concentration (MFC) of the fractions along total extract were determined by microdilution method on nystatin-resistant and susceptible Candida albicans. The Folin-Ciocalteu method was used to determine the total phenolic content of the extract.

Results

The extraction yield (w/w) was 13.50 for TE, 2.10 for PE, 2.23 for Ch, 2.14 for EA, and 10.03 for ME fractions. Chloroform extract showed good anti-candida activity against nystatin susceptible and resistant C. albicans (62.5 ​μg/mL). Ethyl acetate fraction exhibited the greatest MIC against nystatin susceptible and resistant C. albicans (250 ​μg/mL). The MIC value of fluconazole was >64 μg/mL for both susceptible and -resistant strains. The amount of phenolic compounds of the total extract was reported to be equal to 5.4%, equivalent to gallic acid.

Conclusion

Results revealed that the PE and CH fractions showed greater antifungal effects than the total extract against both susceptible and resistant strains of Candida albicans. It can conclude that active antifungal compounds of the plant belong to a specific group of metabolites, which according to the type of solvent, probably have non-polar nature. Further separation is carrying out.

In vitro pharmacokinetics/pharmacodynamics modeling and efficacy against systemic candidiasis in Drosophila melanogaster of a bisaryloxypropanamine derivative

The number of deaths due to systemic fungal infections is increasing alarmingly, which is aggravated by the limitations of traditional treatments and multidrug resistance. Therefore, the research and development of new therapeutic options against pathogenic fungi is an urgent need. To evaluate the fungicidal activity of a synthetic compound, 1,3-bis-(3,4-dichlorophenoxy)propan-2-aminium chloride (2j), through time-kill studies and pharmacokinetics/pharmacodynamics (PK/PD) modeling. The protective effect of the compound was also evaluated using the Drosophila melanogaster minihost model of candidiasis. Mathematical modeling of time-kill data of compound 2j was performed to obtain PD characteristics. Additionally, Toll-deficient D. melanogaster flies were infected with a Candida albicans strain and treated with 2j. We observed that compound 2j demonstrated a time- and dose-dependent fungicidal effect against Candida spp. and dermatophytes, even at low concentrations, and rapidly achieved kill rates reaching the maximum effect in less than one hour. The efficacy of the compound against systemic candidiasis in D. melanogaster flies was comparable to that achieved by fluconazole. These results support the potential of compound 2j as a systemic antifungal agent candidate and serve as a starting point for further studies involving mammalian animal models.

Whole slide imaging is a high-throughput method to assess Candida biofilm formation

New strategies that enable fast and accurate visualization of Candida biofilms are necessary to better study their structure and response to antifungals agents. Here, we applied whole slide imaging (WSI) to study biofilm formation of Candida species. Three relevant biofilm-forming Candida species (C. albicans ATCC 10231, C. glabrata ATCC 2001, and C. tropicalis ATCC 750) were cultivated on glass coverslips both in presence and absence of widely used antifungals. Accumulated biofilms were stained with fluorescent markers and scanned in both bright-field and fluorescence modes using a WSI digital scanner. WSI enabled clear assessment of both size and structural features of Candida biofilms. Quantitative analyses readily detected reductions in biofilm-covered surface area upon antifungal exposure. Furthermore, we show that the overall biofilm growth can be adequately assessed across both bright-field and fluorescence modes. At the single-cell level, WSI proved adequate, as morphometric parameters evaluated with WSI did not differ significantly from those obtained with scanning electron microscopy, considered as golden standard at single-cell resolution. Thus, WSI allows for reliable visualization of Candida biofilms enabling both large-scale growth assessment and morphometric characterization of single-cell features, making it an important addition to the available microscopic toolset to image and analyse fungal biofilm growth.

Antifungal activity of polymethyl methacrylate/Si3N4 composites against Candida albicans

Previous studies using gram-positive and -negative bacteria demonstrated that hydrolysis of silicon nitride (Si₃N₄) in aqueous suspensions elutes nitrogen and produces gaseous ammonia while buffering pH. According to immunochemistry assays, fluorescence imaging, and in situ Raman spectroscopy, we demonstrate here that the antipathogenic surface chemistry of Si₃N₄ can be extended to polymethylmethacrylate (PMMA) by compounding it with a minor fraction (~8 vol.%) of Si₃N₄ particles without any tangible loss in bulk properties. The hydrolytic products, which were eluted from partly exposed Si₃N₄ particles at the composite surface, exhibited fungicidal action against Candida albicans. Using a specific nitrative stress sensing dye and highly resolved fluorescence micrographs, we observed in situ congestion of peroxynitrite (ONOO^-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si₃N₄ composite, while these radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. These in situ observations suggest that the surface chemistry of Si₃N₄ mimics the antifungal activity of macrophages, which concurrently produce NO radicals and superoxide anions (O₂•^-) resulting in the formation of candidacidal ONOO^-. The fungicidal properties of PMMA/Si₃N₄ composites could be used in dental appliances to inhibit the uncontrolled growth of Candida albicans and ensuing candidiasis while being synergic with chemoprophylaxis. STATEMENT OF SIGNIFICANCE: In a follow-up of previous studies of gram-positive and gram-negative bacteria, we demonstrate here that the antipathogenic surface chemistry of Si₃N₄ could be extended to polymethylmethacrylate (PMMA) containing a minor fraction (~8 vol.%) of Si₃N₄ particles without tangible loss in bulk properties. Hydrolytic products eluted from Si₃N₄ particles at the composite surface exhibited fungicidal action against Candida albicans. Highly resolved fluorescence microscopy revealed congestion of peroxynitrite (ONOO^-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si₃N₄ composite, while radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. The fungicidal properties of PMMA/Si₃N₄ composites could be used in dental appliances to inhibit uncontrolled growth of Candida albicans and ensuing candidiasis in synergy with chemoprophylaxis.

Antifungal Resistance of Candida Species Isolated from HIV Patients in a Tertiary Care Hospital, Mysuru, Karnataka

Context:

Candidiasis still remains as a common opportunistic infection in patients with human immunodeficiency virus (HIV). Drug resistance has become a serious health concern because of indiscriminate usage and dosage.

Aim:

To determine the antifungal resistance pattern of Candida albicans and non-albicans Candida (NAC) from HIV patients.

Subjects and Methods:

The study was carried out in the department of microbiology at a tertiary care hospital. Candida isolates obtained from HIV patients were tested for drug susceptibility by Vitek-2 automated system.

Results:

Antifungal susceptibility pattern (n=109) revealed that 15% of the isolates were resistant to at-least one and 85% were sensitive to all the drugs tested. About 10% and 19% of C. albicans showed resistance to fluconazole and flucytosine respectively. Among non-albicans tested, only C. tropicalis (14%) exhibited resistance to flucytosine.

Conclusions:

Knowledge on epidemiology, species prevalence, and drug resistance pattern may guide for effective therapy. This reduces morbidity and also improves the quality of life.

Mucoadhesive bilayered buccal platform for antifungal drug delivery into the oral cavity

A drug delivery technology comprising a mucoadhesive bilayered buccally anchored tablet containing natamycin was developed. The concept was to anchor the tablet to the buccal tissue and allow controlled release of the drug through the matrix into the mouth. Carbomer (Carbopol ® 974 P NF) was used to formulate the mucoadhesive layer. Hydroxypropyl methylcellulose (HPMC) (Methocel® K4M) at 10, 15, 20, and 40% w/w was used for the drug-containing layer. Natamycin, an amphoteric macrolide antifungal agent, was incorporated into the formulations. In addition, tablets containing erythrosine as a marker were prepared in order to examine the distribution and retention of the dye in the oral cavity. As expected, the in vitro analysis showed that the concentration of natamycin released decreased with the increasing proportion of HPMC in the formulation. A small volunteer study was conducted using the tablets containing 10% and 20% HPMC to quantitate the patterns of distribution of the drug released into the oral cavity (upper right buccal vestibule, lower right and left buccal vestibules, and sublingual region). The mucoadhesive bilayered buccal tablet formulation provided a unidirectional release of the drug from the tablet into the oral cavity in a prolonged release fashion, maintaining drug concentration above the MIC value (2 μg/mL) for Candida albicans. The amount of the drug in the sublingual region was found to be lowest when compared with other regions, which is due to the higher flow of saliva in this region. Graphical abstract.

Design, synthesis, and evaluation of novel 2-substituted 1,4-benzenediol library as antimicrobial agents against clinically relevant pathogens

Development of new antimicrobial agents, capable of combating resistant and multidrug-resistant fungal and bacterial clinical strains, is necessary. This study presents the synthesis and antimicrobial screening of 42 2-substituted-1,4-benzenediols, being 10 novel compounds. In total, 23 compounds showed activity against fungi and/or bacteria. Benzenediol compounds 2, 5, 6, 8, 11, and 12 demonstrated broad spectrum antimicrobial actions, including resistant and multidrug-resistant species of dermatophytes (Trichophyton mentagrophytes), Candida spp. and the ESKAPE panel of bacteria. Minimum inhibitory concentrations of these compounds for fungi and bacterial strains ranged from 25 to 50 µg/ml and 8-128 µg/ml, respectively. The antifungal mechanism of action is related to the fungal cell wall of dermatophytes and membrane disruption to dermatophytes and yeasts, in the presence of compound 8. Specific structural changes, such as widespread thinning along the hyphae and yeast lysis, were observed by scanning electron microscopy. The effects of compound 8 on cell viability are dose-dependent; however they did not cause genotoxicity and mutagenicity in human leukocyte cells nor haemolysis. Moreover, the compounds were identified as nonirritant by the ex-vivo Hen's egg test-chorioallantoic membrane (HET-CAM). The furan-1,4-benzenediol compound 5 showed in vivo efficacy to combat S. aureus infection using embryonated chicken eggs. Therefore, the compounds 8, and 5 are promising as hits for the development of new antimicrobial drugs with reduced toxicity.

Candida isolates causing refractory or recurrent oropharyngeal candidiasis in 11 hospitals in China

Introduction: We studied the species distribution and antifungal susceptibilities of Candida isolates causing refractory or recurrent oropharyngeal candidiasis (OPC) in a multicenter study in China (2013–2016).

Methods: Species identification was performed using the Bruker Biotyper (Bruker Daltonics, Germany) matrix-assisted laser desorption/ionization time of flight mass spectrometry system supplemented by internal transcribed spacer sequencing as required. Antifungal susceptibilities were determined by the Clinical and Laboratory Standards Institute document (CLSI) M27-A3 broth microdilution methodology.

Results: A total of 558 non-duplicate Candida isolates comprising 10 species were obtained from 535 patients. Candida albicans was the most common species (89.6%), followed by C. glabrata (5.2%), C. tropicalis (2.9%), and C. parapsilosis (0.7%). Azoles were active against C. albicans with susceptibility rates of 96% and 95.8% for fluconazole and voriconazole, respectively. MIC₅₀ values of C. albicans to fluconazole, voriconazole, itraconazole, and miconazole were 1, 0.03, 0.25 and 0.12 μg/mL, respectively, higher than those in previous studies of which OPC patients (corresponding MIC₅₀ values of 0.25 , 0.015 , 0.06 , and 0.03 μg/mL). Except for itraconazole, the MIC₅₀ and MIC₉₀ values of 58 non-C. albicans to other azoles were two to threefold higher than C. albicans. Miconazole, amphotericin B, nystatin, and 5-flucytosine had good in vitro antifungal activity for all isolates.

Conclusion: The study provides valuable data on the species distribution and antifungal susceptibility of oropharyngeal Candida isolates from geographically diverse areas of China. C. albicans remains the most common species but with increasing rates of azoles resistance.

Anadenanthera Colubrina vell Brenan: anti-Candida and antibiofilm activities, toxicity and therapeutical action

We evaluated the antifungal and antibiofilm potential of the hydroalcoholic extract of bark from Anadenanthera colubrina (vell.) Brenan, known as Angico, against Candida spp. Antifungal activity was evaluated using the microdilution technique through the Minimum Inhibitory and Fungicide Concentrations (MIC and MFC). The antibiofilm potential was tested in mature biofilms formed by Candida species and analyzed through the counting of CFU/mL and scanning electron micrograph (SEM). In vivo toxicity and therapeutic action was evaluated in the Galleria mellonella model. The treatment with the extract, in low doses, was able to reduce the growth of planktonic cells of Candida species. MIC values range between 19.5 and 39 µg/mL and MFC values range between 79 and 625 µg/mL. In addition was able to reduce the number of CFU/mL in biofilms and to cause structural alteration and cellular destruction, observed via SEM. A. colubrina showed low toxicity in the in vivo assay, having not affected the viability of the larvae at doses below 100mg/kg and high potential in the treatment of C. albicans infection. Considering its high antifungal potential, its low toxicity and potential to treatment of infections in in vivo model, A. colubrina extract is a strong candidate for development of a new agent for the treatment of oral candidiasis.

Structure-based design of δ-lactones for new antifungal drug development: susceptibility, mechanism of action, and toxicity

Dermatophytes are the etiological agents of cutaneous mycoses, including the prevalent nail infections and athlete's foot. Candida spp. are opportunistic and emerging pathogens, causing superficial to deeper infections related to high mortality rates. As a consequence of prolonged application of antifungal drugs, the treatment failures combined with multidrug-resistance have become a serious problem in clinical practice. Therefore, novel alternative antifungals are required urgently. δ-Lactones have attracted great interest owing to their wide range of biological activity. This article describes the antifungal activity of synthetic δ-lactones against yeasts of the genus Candida spp. and dermatophytes (through the broth microdilution method), discusses the pathways by which the compounds exert this action (toward the fungal cell wall and/or membrane), and evaluates the toxicity to human leukocytes and chorioallantoic membrane (by the hen's egg test-chorioallantoic membrane). Two of the compounds in the series presented broader spectrum of antifungal activity, including against resistant fungal species. The mechanism of action was related to damage in the fungal cell wall and membrane, with specific target action dependent on the type of substituent present in the δ-lactone structure. The damage in the fungal cell was corroborated by electron microscopy images, which evidenced lysed and completely altered cells after in vitro treatment with δ-lactones. Toxicity was dose dependent for the viability of human leukocytes, but none of the compounds was mutagenic, genotoxic, or membrane irritant when evaluated at higher concentrations than MIC. In this way, δ-lactones constitute a class with excellent perspectives regarding their potential applications as antifungals.

Missense mutation in CgPDR1 regulator associated with azole-resistant Candida glabrata recovered from Thai oral candidiasis patients

OBJECTIVES

Non-albicans Candida (NAC) species are increasingly identified as pathogens causing oral candidiasis. Incidence rates for azole resistance among NAC species have been continuously reported. This study aimed to evaluate the azole susceptibility profiles and to characterise the azole resistance mechanisms of oral clinical NAC isolates.

METHODS

In vitro susceptibility patterns of 85 NAC species isolates were determined by the broth microdilution method. Azole resistance-related genes (ERG3, ERG11 and PDR1) of Candida glabrata isolates were sequenced to determine the presence of nucleotide substitutions. Expression levels of various resistance-related genes were also evaluated by RT-qPCR in azole-susceptible, susceptible dose-dependent (SDD) and resistant Candida isolates.

RESULTS

Two C. glabrata isolates (2.4% of all NAC isolates) were resistant to all three azoles tested (fluconazole, itraconazole and ketoconazole). All clinical isolates of Candida tropicalis and Candida kefyr were susceptible to azoles. Silent mutations were found in the CgERG11 and CgERG3 genes of clinical C. glabrata isolates. Interestingly, two missense mutations in CgPDR1 (N768D and E818K) were identified only in resistant C. glabrata isolates. The presence of a CgPDR1 missense mutation in resistant isolates is associated with overexpression of its own product as well as multidrug transporters including ABC and MFS transporters.

CONCLUSION

A gain-of-function (GOF) mutation in CgPDR1 is associated with upregulation of various drug transporters, which appears to serve as a primary mechanism for azole resistance in the detected C. glabrata isolates. Therefore, analysis of GOF mutations in the PDR1 regulator provides a better understanding of the development of antifungal resistance.

Prevalence and antifungal susceptibility profiles of Candida glabrata, Candida parapsilosis and their close-related species in oral candidiasis

OBJECTIVE

To evaluate the importance of Candida glabrata, Candida parapsilosis and their close-related species, Candida bracarensis, Candida nivariensis, Candida metapsilosis and Candida orthopsilosis in patients with oral candidiasis and, to determine the in vitro activities of antifungal drugs currently used for the treatment.

METHODS

One hundred fourteen isolates of C. glabrata and 97 of C. parapsilosis, previously identified by conventional mycological methods, were analysed by molecular techniques. In vitro antifungal susceptibility to fluconazole, itraconazole, miconazole, and nystatin was evaluated by CLSI M44-A2 disk diffusion test, and by CLSI M27-A3 microdilution for fluconazole.

RESULTS

All C. glabrata isolates were identified as C. glabrata sensu stricto, 93 out of 97 C. parapsilosis isolates as C. parapsilosis sensu stricto, three as C. orthopsilosis and one as C. metapsilosis. Candida glabrata was mainly isolated in mixed cultures but C. parapsilosis complex was more frequent in pure culture. Candida metapsilosis and C. orthopsilosis were isolated as pure culture and both species were susceptible to all antifungal agents tested. Most C. glabrata isolates were susceptible to miconazole and nystatin, but resistant to fluconazole and itraconazole. Azole cross resistance was also observed. Candida parapsilosis isolates were susceptible to fluconazole although azole cross resistance to miconazole and itraconazole was observed.

CONCLUSION

This study highlights the importance of accurate identification and antifungal susceptibility testing of oral Candida isolates in order to have an in-depth understanding of the role of C. glabrata and C. parapsilosis in oral candidiasis.

Fluconazole impacts the extracellular matrix of fluconazole-susceptible and -resistant Candida albicans and Candida glabrata biofilms

Background: Fluconazole (FLZ) is a drug commonly used for the treatment of Candida infections. However, β-glucans in the extracellular matrices (ECMs) hinder FLZ penetration into Candida biofilms, while extracellular DNA (eDNA) contributes to the biofilm architecture and resistance. Methods: This study characterized biofilms of FLZ-sensitive (S) and -resistant (R) Candida albicans and Candida glabrata in the presence or absence of FLZ focusing on the ECM traits. Biofilms of C. albicans American Type Culture Collection (ATCC) 90028 (CaS), C. albicans ATCC 96901 (CaR), C. glabrata ATCC 2001 (CgS), and C. glabrata ATCC 200918 (CgR) were grown in RPMI medium with or without FLZ at 5× the minimum inhibitory concentration (37°C/48 h). Biofilms were assessed by colony-forming unit (CFU)/mL, biomass, and ECM components (alkali-soluble polysaccharides [ASP], water-soluble polysaccharides [WSP], eDNA, and proteins). Scanning electron microscopy (SEM) was also performed. Data were analyzed by parametric and nonparametric tests (α  =  0.05). Results: In biofilms, FLZ reduced the CFU/mL of all strains (p < 0.001), except for CaS (p = 0.937). However, the ASP quantity in CaS was significantly reduced by FLZ (p = 0.034), while the drug had no effect on the ASP levels in other strains (p > 0.05). Total biomasses and WSP were significantly reduced by FLZ in the ECM of all yeasts (p < 0.001), but levels of eDNA and proteins were unaffected (p > 0.05). FLZ affected the cell morphology and biofilm structure by hindering hyphae formation in CaS and CaR biofilms, by decreasing the number of cells in CgS and CgR biofilms, and by yielding sparsely spaced cell agglomerates on the substrate. Conclusion: FLZ impacts biofilms of C. albicans and C. glabrata as evident by reduced biomass. This reduced biomass coincided with lowered cell numbers and quantity of WSPs. Hyphal production by C. albicans was also reduced.

Prevalence of Candida species in the buccal cavity of diabetic and non-diabetic individuals in and around Pondicherry

OBJECTIVES

The aim of the present study was to determine the prevalence of Candida in the buccal cavity of diabetic and non-diabetic individuals in and around Pondicherry, India and to analyse the antifungal susceptibility profile of the selected isolates.

MATERIALS AND METHODS

A total of 400 buccal samples, 200 each from diabetic and non-diabetic healthy individuals were included in the study. Sabouraud's dextrose agar was used for isolation of Candida species. Identification was performed through microscopy, germ tube test, sugar fermentation test, sugar assimilation test and by using Hichrome agar. Distinct and phenotypically representative colonies were selected and subjected to ITS analysis. In vitro antifungal susceptibility testing for the isolated Candida species was performed using E-test.

RESULTS

Results revealed that the prevalence of Candida species in diabetic individuals was higher when compared with non-diabetic healthy individuals. The most predominantly isolated species in diabetic and non-diabetic individuals from buccal cavity was Candida albicans. C. tropicalis was predominant among the non-albicans Candida isolated from both diabetic and non-diabetic individuals. Among denture wearers C. glabrata was predominant. In vitro antifungal susceptibility testing shows that ketoconazole, fluconazole and itraconazole were effective against the isolated Candida species.

CONCLUSIONS

The rate of candidal carriage in diabetic individuals is higher. Different species of Candida are present in the oral cavity of diabetic individuals. There may be a positive correlation between glycemic control and candidal colonization. In vitro antifungal susceptibility testing of Candia species are required for proper management and treatment of candidal infections.

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.

Current treatment of oral candidiasis: A literature review

Candidiasis or oral candidosis is one of the most common human opportunistic fungal infections of the oral cavity. This pathology has a wide variety of treatment which has been studied until these days. The present study offers a literature review on the treatment of oral candidiasis, with the purpose of establish which treatment is the most suitable in each case. Searching the 24 latest articles about treatment of candidiasis it concluded that the incidence depends on the type of the candidiasis and the virulence of the infection. Although nystatin and amphotericin b were the most drugs used locally, fluconazole oral suspension is proving to be a very effective drug in the treatment of oral candidiasis. Fluconazole was found to be the drug of choice as a systemic treatment of oral candidiasis. Due to its good antifungal properties, its high acceptance of the patient and its efficacy compared with other antifungal drugs. But this drug is not always effective, so we need to evaluate and distinguish others like itraconazole or ketoconazole, in that cases when Candida strains resist to fluconazole.

Key words:Candidiasis, treatment, miconazole, fluconazole, nystatin.

Anti-Candida activity of 1-18 fragment of the frog skin peptide esculentin-1b: in vitro and in vivo studies in a Caenorhabditis elegans infection model

Candida albicans represents one of the most prevalent species causing life-threatening fungal infections. Current treatments to defeat Candida albicans have become quite difficult, due to their toxic side effects and the emergence of resistant strains. Antimicrobial peptides (AMPs) are fascinating molecules with a potential role as novel anti-infective agents. However, only a few studies have been performed on their efficacy towards the most virulent hyphal phenotype of this pathogen. The purpose of this work is to evaluate the anti-Candida activity of the N-terminal 1-18 fragment of the frog skin AMP esculentin-1b, Esc(1-18), under both in vitro and in vivo conditions using Caenorhabditis elegans as a simple host model for microbial infections. Our results demonstrate that Esc(1-18) caused a rapid reduction in the number of viable yeast cells and killing of the hyphal population. Esc(1-18) revealed a membrane perturbing effect which is likely the basis of its mode of action. To the best of our knowledge, this is the first report showing the ability of a frog skin AMP-derived peptide (1) to kill both growing stages of Candida; (2) to promote survival of Candida-infected living organisms and (3) to inhibit transition of these fungal cells from the roundish yeast shape to the more dangerous hyphal form at sub-inhibitory concentrations.

Novel Nystatin A₁ derivatives exhibiting low host cell toxicity and antifungal activity in an in vitro model of oral candidosis

Opportunistic oral infections caused by Candida albicans are frequent problems in immunocompromised patients. Management of such infections is limited due to the low number of antifungal drugs available, their relatively high toxicity and the emergence of antifungal resistance. Given these issues, our investigations have focused on novel derivatives of the antifungal antibiotic Nystatin A1, generated by modifications at the amino group of this molecule. The aims of this study were to evaluate the antifungal effectiveness and host cell toxicity of these new compounds using an in vitro model of oral candidosis based on a reconstituted human oral epithelium (RHOE). Initial studies employing broth microdilution, revealed that against planktonic C. albicans, Nystatin A1 had lower minimal inhibitory concentration than novel derivatives. However, Nystatin A1 was also markedly more toxic against human keratinocyte cells. Interestingly, using live/dead staining to assess C. albicans and tissue cell viability after RHOE infection, Nystatin A1 derivatives were more active against Candida with lower toxicity to epithelial cells than the parent drug. Lactate dehydrogenase activity released by the RHOE indicated a fourfold reduction in tissue damage when certain Nystatin derivatives were used compared with Nystatin A1. Furthermore, compared with Nystatin A1, colonisation of the oral epithelium by C. albicans was notably reduced by the new polyenes. In the absence of antifungal agents, confocal laser scanning microscopy showed that C. albicans extensively invaded the RHOE. However, the presence of the novel derivatives greatly reduced or totally prevented this fungal invasion.

Minimal inhibitory concentration (MIC) of caspofungin and itraconazole inhibiting growth of Candida strains calculated from the linear regression equation

PURPOSE

The aim of the study was to compare the susceptibility of Candida species to caspofungin and itraconazole.

MATERIAL AND METHODS

118 strains of Candida species were used in the study: 8 pattern strains and 110 strains isolated from different ontocenoses. The susceptibility of fungi strains to drugs was determined by diffusion in agar gel. The minimal inhibitory concentration (MIC) was calculated from the linear regression equation with the use of the method by Kadłubowski.

RESULTS

The MIC value for caspofungin for the pattern strains ranged from 0.321 mg/L to 0.552 mg/L and for itraconazole from 0.019 mg/L to 0.11 mg/L. All the analyzed strains isolated from patients exhibited susceptibility to caspofungin; 5 strains of Candida albicans (8.06%) proved to be resistant to itraconazole. The MIC values for caspofungin ranged from 0.114 mg/L to 1.26 mg/L and for itraconazole from 0.012 mg/L to 16.1 mg/L.

CONCLUSIONS

1. All the studied pattern strains are susceptible to the examined drugs; all those isolated from patients show susceptibility to caspofungin; some Candida albicans strains (8.06%) are resistant to itraconazole. 2. The mean MIC values calculated from the activity curves are 0.426 mg/L for caspofungin and 1.0245 mg/L for itraconazole. 3. The mean MIC values calculated for caspofungin are lower than for itraconazole in the case of Candida albicans, C. glabrata and C. tropicalis. Having compared the influence of the drugs on C. famata, C. lusitaniae, C. parapsilosis and C. ciferri we proved there are statistically significant differences (0.0046>p<0.044).

In vitro susceptibility of e.faecalis and c.albicans isolates from apical periodontitis to common antimicrobial agents, antibiotics and antifungal medicaments

The aim of this study was to evaluate in vitro antimicrobial activity of 4 antibiotic agents (for E.faecalis) and 4 antifungal agents (for C.albicans) by agar dilution method. Additionally, modified strip diffusion method was used for detection of in vitro antimicrobial activities of 5% NaOCl, 2.5% NaOCl, 17% EDTA and 2% CHX and agar diffusion method for detection of in vitro susceptibilities of three intracanal medicaments for 18 E.faecalis and 18 C.albicans isolates from primary and secondary root canal infection. Isolates were recovered from 231 endodontic samples of patients, with the need of root canal treatment and retreatment. All tested E.faecalis isolates showed resistance to antibiotics. For irrigation solutions, 2% CHX was more effective in eliminating E.faecalis but 5% NaOCl showed larger inhibition zone than 2.5% NaOCl, 17% EDTA and 2% CHX. For intracanal medication, Ca(OH)2-CHX worked efficiently in killing E.faecalis isolates compared to Ca(OH)2-Steril saline solution, Ca(OH)2-Glycerin. For C.albicans, 18 isolates were susceptible to amphotericin B, nistatin, fluconazole but showed resistance to ketoconazole. 5% NaOCl was more effective in eliminating and produced larger inhibition zone compared to 2.5% NaOCl, 17% EDTA and 2% CHX. Ca(OH)2-Glycerin intracanal medication was better in eliminating C.albicans isolates and produced larger inhibition zone compared to other Ca(OH)2 medicaments.

Key words:E.faecalis, C.albicans, antimicrobial, antibiotic, antifungal.

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).

In vitro activity of voriconazole against Mexican oral yeast isolates

Oral candidiasis is the most prevalent complication in HIV-infected and AIDS patients. Topical antifungal treatment is useful for the initial episodes of oral candidiasis, but most patients suffer more than one episode and fluconazole or itraconazole can help in the management, and voriconazole may represent a useful alternative agent for the treatment of recalcitrant oral and oesophageal candidiasis. The aim of this research was to study the in vitro activity of voriconazole and fluconazole against Mexican oral isolates of clinically relevant yeast. The in vitro susceptibility of 187 oral yeast isolates from HIV-infected and healthy Mexicans was determined for fluconazole and voriconazole by the M44-A disc diffusion method. At 24 h, fluconazole was active against 179 of 187 isolates (95.7 %). Moreover, a 100% susceptibility to voriconazole was observed. Voriconazole and fluconazole are highly active in vitro against oral yeast isolates. This study provides baseline data on susceptibilities to both antifungal agents in Mexico.

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.

Treatment strategies for oropharyngeal candidiasis

BACKGROUND

Oropharyngeal candidiasis (OPC) is a common oral disease that may cause oral symptoms, lead to regional infection (e.g., esophageal candidiasis) and increase the risk of systemic fungal infection in the compromised host.

OBJECTIVE

Critical review of the literature of prevention and therapy.

METHODS

The literature was reviewed using PubMed, and specific keywords from the MeSH Database were used.

RESULTS/CONCLUSION

Management of OPC requires that the underlying risk factors of infection be diagnosed and managed whenever possible. Antimicrobials may be provided as topical or systemic therapy. Topical therapies may provide effective management for candidiasis in the non-compromised host and increase the control of colonization in the compromised host. Advances in prevention and management include new agents and improved mechanisms of topical drug delivery.

Nanodisks protect amphotericin B from ultraviolet light and oxidation-induced damage

BACKGROUND

Macrolide polyene antibiotics possess potent broad-spectrum antifungal properties. Use of these agents in the field or in controlled environments is impeded by their poor water solubility and susceptibility to oxidation- and/or light-induced degradation. While typically used for human disease therapy, there is potential to expand the utility of polyene macrolide antibiotics, such as amphotericin B, for control of fungal disease infestation in agricultural settings. Thus, the susceptibility of this antibiotic to exposure-induced activity loss was evaluated.

RESULTS

Incubation of the prototype polyene amphotericin B (AMB) with phospholipid vesicles and apolipoprotein A-I results in the formation of nanoscale complexes, termed nanodisks (NDs), capable of solubilizing significant quantities of AMB. To evaluate whether AMB incorporation into NDs conferred protection against light- or oxidation-induced damage, yeast growth inhibition assays were conducted. Compared with AMB solubilized in detergent micelles, AMB incorporated into NDs was protected from damage caused by exposure to UV light as well as by KMnO(4)-induced oxidation. Furthermore, AMB-NDs inhibited growth of the turfgrass fungus Marasmius oreades Fr.

CONCLUSION

Results suggest that this water-soluble formulation of a natural, biodegradable, antifungal agent represents a potential cost-effective, non-toxic and environmentally friendly substitute for chemical agents currently employed to control a range of fungal infestations.

Antifungal suscepitibility profile of candida spp. oral isolates obtained from denture wearers

Denture stomatitis is an inflammatory condition that occurs in denture wearers and is frequently associated with Candida yeasts. Antifungal susceptibility profiles have been extensively evaluated for candidiasis patients or immunosupressed individuals, but not for healthy Candida carriers. In the present study, fluconazole, itraconazole, voriconazole, terbinafine and 5-flucytosin were tested against 109 oral Candida spp. isolates. All antifungal agents were effective against the samples tested except for terbinafine. This work might provide epidemiological information about Candida spp. drug susceptibility in oral healthy individuals.

Candida albicans and Candida tropicalis in oral candidosis: quantitative analysis, exoenzyme activity, and antifungal drug sensitivity

Candida albicans and C. tropicalis obtained from whole saliva of patients presenting signs of oral candidosis were assayed for quantification of colony forming units, exoenzyme activity (phospholipase and proteinase) and antifungal drug sensitivity (amphotericin B, fluconazole and itraconazole) by the reference method of the Clinical and Laboratory Standards Institute. The number of colony forming units per milliliter varied according to the Candida species involved and whether a single or mixed infection was present. Proteinase activity was observed in both C. albicans and C. tropicalis, but phospholipase activity was noted only in C. albicans. In vitro resistance to antifungals was verified in both species, but C. tropicalis appears to be more resistant to the tested antifungals than C. albicans.

Species distribution and in vitro antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

Background

In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis.

Methods

A total of 296 clinical oral yeasts were isolated from 292 HIV-infected patients with oropharyngeal candidiasis at the Muhimbili National Hospital, Dar es Salaam, Tanzania. Identification of the yeasts was performed using standard phenotypic methods. Antifungal susceptibility to fluconazole, itraconazole, miconazole, clotrimazole, amphotericin B and nystatin was assessed using a broth microdilution format according to the guidelines of the Clinical and Laboratory Standard Institute (CLSI; M27-A2).

Results

Candida albicans was the most frequently isolated species from 250 (84.5%) patients followed by C. glabrata from 20 (6.8%) patients, and C. krusei from 10 (3.4%) patients. There was no observed significant difference in species distribution between patients with primary and recurrent oropharyngeal candidiasis, but isolates cultured from patients previously treated were significantly less susceptible to the azole compounds compared to those cultured from antifungal naïve patients.

Conclusion

C. albicans was the most frequently isolated species from patients with oropharyngeal candidiasis. Oral yeast isolates from Tanzania had high level susceptibility to the antifungal agents tested. Recurrent oropharyngeal candidiasis and previous antifungal therapy significantly correlated with reduced susceptibility to azoles antifungal agents.

Potent in vitro antifungal activities of naturally occurring acetylenic acids

Our continuing effort in antifungal natural product discovery has led to the identification of five 6-acetylenic acids with chain lengths from C(16) to C(20): 6-hexadecynoic acid (compound 1), 6-heptadecynoic acid (compound 2), 6-octadecynoic acid (compound 3), 6-nonadecynoic acid (compound 4), and 6-icosynoic acid (compound 5) from the plant Sommera sabiceoides. Compounds 2 and 5 represent newly isolated fatty acids. The five acetylenic acids were evaluated for their in vitro antifungal activities against Candida albicans, Candida glabrata, Candida krusei, Candida tropicalis, Candida parapsilosis, Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Trichophyton mentagrophytes, and Trichophyton rubrum by comparison with the positive control drugs amphotericin B, fluconazole, ketoconazole, caspofungin, terbinafine, and undecylenic acid. The compounds showed various degrees of antifungal activity against the 21 tested strains. Compound 4 was the most active, in particular against the dermatophytes T. mentagrophytes and T. rubrum and the opportunistic pathogens C. albicans and A. fumigatus, with MICs comparable to several control drugs. Inclusion of two commercially available acetylenic acids, 9-octadecynoic acid (compound 6) and 5,8,11,14-eicosatetraynoic acid (compound 7), in the in vitro antifungal testing further demonstrated that the antifungal activities of the acetylenic acids were associated with their chain lengths and positional triple bonds. In vitro toxicity testing against mammalian cell lines indicated that compounds 1 to 5 were not toxic at concentrations up to 32 muM. Furthermore, compounds 3 and 4 did not produce obvious toxic effects in mice at a dose of 34 mumol/kg of body weight when administered intraperitoneally. Taking into account the low in vitro and in vivo toxicities and significant antifungal potencies, these 6-acetylenic acids may be excellent leads for further preclinical studies.

Association of oral yeast carriage with specific host factors and altered mouth sensation

OBJECTIVES

The aim of this study was to determine if there was a significant association between the presence of altered mouth and taste sensations with oral carriage of yeasts and to assess the factors that influence the yeast carriage.

STUDY DESIGN

The oral and dental status including unstimulated (USFR) and stimulated (SSFR) whole salivary flow rates of a total of 509 subjects was recorded. Saliva specimens were collected for microbiologic examination. Multiple logistic regression analysis was performed to identify any factors that were significantly associated with the prevalence of oral yeasts.

RESULTS

Old age, clinical signs of oral dryness, denture wearing, and a reduction in USFR increased the prevalence of yeasts, whereas patient gender, levels of dentition, the sensation of dry or burning mouth, taste disorders, and SSFR were not associated with increased prevalence of oral yeasts.

CONCLUSIONS

An increased prevalence of oral yeasts was not found to relate to changes in mouth sensation alone. Other factors, most notably patient age, the wearing of dentures, clinical signs of oral dryness, and salivary flow rate under rest conditions, were, however, found to be closely associated with oral yeast carriage.

Comparison of the efficacy and safety of miconazole 50-mg mucoadhesive buccal tablets with miconazole 500-mg gel in the treatment of oropharyngeal candidiasis: a prospective, randomized, single-blind, multicenter, comparative, phase III trial in patients treated with radiotherapy for head and neck cancer

BACKGROUND

Topical antifungal treatments are recommended but rarely used as first-line therapy for oropharyngeal candidiasis (OPC) in patients with cancer. Miconazole Lauriad 50-mg mucoadhesive buccal tablet (MBT) Loramyc reportedly delivered rapid and prolonged, effective concentrations of miconazole in the mouth. The objective of the current study was to compare MBT with miconazole 500-mg oral gel (MOG) in patients with head and neck cancer.

METHODS

Two hundred eighty-two patients with head and neck cancer received a 14-day treatment of either single-dose MBT or MOG administered in 4 divided doses. The primary endpoint was clinical success at Day 14, and secondary endpoints included clinical success at Day 7, clinical cure, improvement in clinical symptoms, mycologic cure, recurrence rate, and safety.

RESULTS

The success rate was statistically not inferior (P < .0001) in the MBT population to the rate observed in the MOG group (56% vs 49%, respectively; P < .0001). After adjustment for the extent of lesions and salivary secretions, a trend toward superiority was observed in favor of MBT (P = .13), particularly among patients with multiple lesions (P = .013). Results for secondary endpoints were comparable to those observed for the primary endpoint. Compliance with MBT was excellent, and >80% of patients completed treatment. Both treatments were safe.

CONCLUSIONS

The success rate of MBT Loramyc was significantly not inferior to that of MOG in the treatment of cancer patients with OPC; and, after adjusting for prognostic variables, it was more effective than MOG. MBT was well tolerated and, thus, may be recommended as first-line treatment in cancer patients who have OPC as an alternative to systemic antifungal agents. Society.

Antifungal susceptibility of Candida species using the Clinical and Laboratory Standards Institute disk diffusion and broth microdilution methods

There are conflicting reports on the agreement between the Clinical and Laboratory Standards Institute disk diffusion (M44-A) and reference broth microdilution (M27-A) methods for determination of antifungal susceptibility of yeasts. The antifungal susceptibility of 541 yeasts, the majority of which were from the oral cavity, was determined using these two methods and the accuracy of the disk diffusion method assessed for clinical testing of various Candida species. Of the strains tested, Candida albicans predominated (390 out of 541). The classification of susceptibility determined by the disk diffusion method was largely in concordance with that obtained using the broth dilution method, regardless of species within Candida genus. The overall observed agreement between these two methods was 94.7% for fluconazole and 96.7% for voriconazole was with a 'very major' discrepancy level of 1.5% and 1.7% respectively. This study demonstrates a strong agreement of the simple disk diffusion method with the more labour intensive 'gold standard' broth microdilution method. These findings would support the use of the disk diffusion method in a routine mycology service.

Advances in topical and systemic antifungals

Topical antifungal agents are generally used for the treatment of superficial fungal infections unless the infection is widespread, involves an extensive area, or is resistant to initial therapy. Systemic antifungals are often reserved for the treatment of onychomycosis, tinea capitis, superficial and systemic candidiasis, and prophylaxis and treatment of invasive fungal infections. With the development of resistant fungi strains and the increased incidence of life-threatening invasive fungal infections in immunocompromised patients, some previously effective traditional antifungal agents are subject to limitations including multidrug interactions, severe adverse effects, and their fungistatic mechanism of actions. Several new antifungal agents have demonstrated significant therapeutic benefits and have broadened clinicians' choices in the treatment of superficial and systemic invasive fungal infections.

Candida pseudorugosa sp. nov., a novel yeast species from sputum

Two yeast strains, strains XH 1026 and XH 1164, isolated from the sputum of an intensive care unit patient with acute pneumonia, were originally identified as Candida albicans and C. tropicalis, respectively. Sequence analysis of the 26S rRNA gene D1/D2 domain and the internal transcribed spacer (ITS) region indicated that the two strains represent a novel yeast species closely related to C. rogusa. The name Candida pseudorugosa sp. nov. is therefore proposed (type strain, AS 2.3107 [CBS 10433]). The new species is able to grow at 42 degrees C and is resistant or insusceptible to amphotericin B (MIC, 2 microg/ml), caspofungin (MIC, 64 microg/ml), itraconazole (MIC, 1 microg/ml), and nystatin (MIC, 16 microg/ml); dose-dependent susceptible to fluconazole (MIC, 16 microg/ml); and susceptible to flucytosine (MIC, 0.125 microg/ml) and voriconazole (MIC, 0.125 to 0.25 microg/ml). The code for C. pseudorugosa sp. nov. provided by the API 20C AUX system is identical to that for C. rugosa. The colonies of the new species on CHROMagar Candida appear blue-green, similar to those of C. albicans. In addition to the molecular method based on D1/D2 domain or ITS region sequencing, use of the combination of the API system and CHROMagar Candida is helpful for the correct identification of C. pseudorugosa sp. nov.

In vitro synergistic effect of farnesol and human gingival cells againstCandida albicans

Farnesol prevents the germination of yeast cells into mycelia, a fact that may be useful in eliminating C. albicans pathogenicity. Given the clinical potential of farnesol, its impact on C. albicans and host cells merited further investigation. We thus studied the effect of farnesol on C. albicans growth and filamentation and on gingival epithelial cells and fibroblasts and the synergistic effect of both gingival cells and farnesol on C. albicans filamentation. Repeated additions of farnesol reduced the growth of C. albicans. Farnesol was also effective at reducing C. albicans germ tube formation. While farnesol inhibited germ tube formation under the conditions tested, it was most effective at inhibiting C. albicans filamentation when added to the culture medium at the same time as the serum. Farnesol also had an effect on gingival cells. In a serum-free medium, farnesol reduced fibroblast adhesion and proliferation, promoted epithelial cell differentiation and reduced proliferation up to 48 h post-treatment. These effects were not seen in the presence of serum. When C. albicans, farnesol and gingival cells were present in the same culture, significantly greater inhibition of the yeast-to-hyphal transition was observed than germ tube inhibition in cultures containing only C. albicans and farnesol, suggesting a synergistic effect between the gingival cells and farnesol in inhibiting the transition. Overall, the data suggest that farnesol is effective against C. albicans and may have an effect on host cells at certain concentrations.