The isolation and identification of Candida glabrata from avian species and a study of the antibacterial activities of Chinese herbal medicine in vitro.

Previously, a fungus was isolated from a diseased pigeon group clinically suspected of being infected with Candida. The fungus was subsequently identified as Candida glabrata using morphology, physiology, biochemistry, and molecular biology testing methods. In the present study, to determine the controlling effects of Chinese herbal medicine for C. glabrata, the bacteriostatic effects of the ethanol extracts Acorus gramineus, Sophora flavescens, Polygonum hydropiper, Cassia obtusifolia, Pulsatilla chinensis, Dandelion, and Cortex phellodendri on C. glabrata in vitro were analyzed. The results showed that the minimum inhibitory concentrations (MIC80) of Cortex phellodendri was 0.25 µg/µL. Meanwhile, that of S. flavescens was 32 µg/µL; C. obtusifolia was 56 µg/µL; A. gramineus and Polygonum hydropiper was 64 µg/µL; and P. chinensis was 112 µg/µL. However, MIC80 for Dandelion was undetectable. In addition, improved drug sensitivity tests revealed that colonies had grown after 24 h in the blank group, as well as the Polygonum hydropiper, P. chinensis, Dandelion, and ethanol groups. The colonies first appeared at the 48-hour point in the other drug-sensitive medium of Chinese herbal medicine. However, no colony growth was found in Cortex phellodendri medium, and the formation of the maximum colony diameter in that group was later than the blank group (e.g., 96 h in the blank group and 120 h in the Chinese herbal medicine group). It was observed that only 17 colony-forming units had grown in 125 µg/µL of the S. flavescens medium, which was significantly different from other groups. Also, the final colony diameter was significantly smaller than that of the other experimental groups. Therefore, it was determined that the A. gramineus, S. flavescens, Polygonum hydropiper, Cassia obtusifolia, P. chinensis, and Cortex phellodendri had certain inhibitory effects on the growth of the C. glabrata. Among those, it was observed that the Cortex phellodendri had the strongest inhibitory effects, followed by the S. flavescens. In the future, these Chinese herbal medicines are expected to be used to treat the fungal infections related to C. glabrata in poultry to improve production performance.

In-vitro pharmacokinetic/pharmacodynamic model data suggest a potential role of new formulations of posaconazole against Candida krusei but not Candida glabrata infections.

Posaconazole exhibits in-vitro activity against Candida glabrata and Candida krusei. Epidemiological cut-off values set by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI) are 1/1 and 0.5/0.5 mg/L, respectively, but clinical breakpoints have not been established to date. This study explored the pharmacodynamics (PD) of posaconazole in a validated one-compartment in-vitro pharmacokinetic (PK)/PD model, and determined the probability of PK/PD target attainment (PTA) for the available formulations. Five C. glabrata and three C. krusei isolates with posaconazole minimum inhibitory concentrations (MICs) of 0.06-2 and 0.03-0.25 mg/L, respectively, were tested in the PK/PD model simulating different time-concentration profiles of posaconazole. The exposure-effect relationship fAUC0-24/MIC was described for EUCAST/CLSI methods, and PTA was calculated in order to determine PK/PD susceptibility breakpoints for oral solution (400 mg q12h), and intravenous (i.v.)/tablet formulations (300 mg q24h). Fungicidal activity (~2log kill) was found against the most susceptible C. glabrata isolate alone, and against all three C. krusei isolates. The corresponding EUCAST/CLSI PK/PD targets (fAUC0-24/MIC) were 102/79 for C. glabrata and 12/8 for C. krusei. Mean PTA was high (>95%) for C. glabrata isolates with EUCAST/CLSI MICs ≤0.03/≤0.03 mg/L for oral solution and ≤0.125/≤0.125 mg/L for i.v. and tablet formulations for the wild-type population. For C. krusei isolates, mean PTA was high (>95%) for EUCAST/CLSI MICs ≤0.25/≤0.5 mg/L for oral solution and ≤1/≤2 mg/L for i.v. and tablet formulations for the wild-type population. The use of posaconazole to treat C. glabrata infections is questionable. Intravenous and tablet formulations may be therapeutic options for the treatment of C. krusei infections, and oral exposure can be optimized with therapeutic drug monitoring (trough levels >0.6-0.9 mg/L).

Low level of antifungal resistance of Candida glabrata blood isolates in Turkey: Fluconazole minimum inhibitory concentration and FKS mutations can predict therapeutic failure.

BACKGROUND: Candida glabrata is the third leading cause of candidaemia in Turkey; however, the data regarding antifungal resistance mechanisms and genotypic diversity in association with their clinical implication are limited. OBJECTIVES: To assess genotypic diversity, antifungal susceptibility and mechanisms of drug resistance of C glabrata blood isolates and their association with patients' outcome in a retrospective multicentre study. PATIENTS/METHODS: Isolates from 107 patients were identified by ITS sequencing and analysed by multilocus microsatellite typing, antifungal susceptibility testing, and sequencing of PDR1 and FKS1/2 hotspots (HSs). RESULTS: Candida glabrata prevalence in Ege University Hospital was twofold higher in 2014-2019 than in 2005-2014. Six of the analysed isolates had fluconazole MICs ≥ 32 µg/mL; of them, five harboured unique PDR1 mutations. Although echinocandin resistance was not detected, three isolates had mutations in HS1-Fks1 (S629T, n = 1) and HS1-Fks2 (S663P, n = 2); one of the latter was also fluconazole-resistant. All patients infected with isolates carrying HS-FKS mutations and/or demonstrating fluconazole MIC ≥ 32 µg/mL (except one without clinical data) showed therapeutic failure (TF) with echinocandin and fluconazole; seven such isolates were collected in Ege (n = 4) and Gulhane (n = 3) hospitals and six detected recently. Among 34 identified genotypes, none were associated with mortality or enriched for fluconazole-resistant isolates. CONCLUSION: Antifungal susceptibility testing should be supplemented with HS-FKS sequencing to predict TF for echinocandins, whereas fluconazole MIC ≥ 32 µg/mL may predict TF. Recent emergence of C glabrata isolates associated with antifungal TF warrants future comprehensive prospective studies in Turkey.

Effect of initial antifungal therapy on mortality among patients with bloodstream infections with different Candida species and resistance to antifungal agents: A multicentre observational study by the Turkish Fungal Infections Study Group.

This study aimed to describe the effect of initial antifungal therapy on patient mortality and to detail the current distribution and resistance patterns of Candida spp. among patients with candidaemia. A prospective observational study was performed among consecutive patients with candidaemia from 10 Turkish medical centres between January 2015 and November 2018. The primary outcome was 10-day mortality. Species were identified using MALDI-TOF/MS. A total of 342 patients with candidaemia were included, of which 175 (51.2%) were male and 68 (19.9%) were aged <18 years. The most common species were Candida albicans (47.4%), Candida parapsilosis (26.6%), Candida tropicalis (9.6%) and Candida glabrata (7.6%). Among all Candida spp., the 10-day case fatality rate (CFR) was 32.2%. The CFR was highest in patients with C. albicans (57.3%) and lowest in patients with C. parapsilosis (21.8%). The resistance rate to fluconazole was 13% in C. parapsilosis, with no significant effect on mortality. No resistance to echinocandins was detected. In the multivariate analysis, being in the ICU [OR = 2.1 (95% CI 1.32-3.57); P = 0.002], renal failure [OR = 2.4 (1.41-3.97); P = 0.001], total parenteral nutrition [OR = 2 (1.22-3.47); P = 0.006], C. albicans infection [OR = 1.7 (1.06-2.82); P = 0.027] and echinocandin as primary agent [OR = 0.6 (0.36-0.99); P = 0.047] were significantly associated with mortality. Candidaemia is a deadly infection. Fluconazole resistance is emerging, although it was not significantly related to mortality. Using an echinocandin as the primary agent could be life-saving.

In vitro anticandidal potency of Syzygium aromaticum (clove) extracts against vaginal candidiasis.

BACKGROUND: Candida vaginitis is a global health hazard that increases morbidity among women of childbearing age. Recent studies have revealed a high incidence of drug-resistant Candida strains. Additionally, treating Candida vulvovaginitis during pregnancy is challenging as antifungal therapy is associated with fetal abnormalities. Hence, it is important to develop novel therapeutic strategies to treat vulvovaginal candidiasis. METHODS: In this study, we used the disc diffusion method to evaluate the anticandidal activity of different Syzygium aromaticum extracts (methanol, ethyl acetate, n-hexane, and diethyl ether) against C. albicans, C. glabrata, and C. tropicalis. Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis of different S. aromaticum extracts was performed to determine active components exhibiting anticandidal activity. Cytotoxicity of different clove extracts against the HUH7 cell line was evaluated. RESULTS: The ethyl acetate extract exhibited the highest antifungal activity against C. albicans, C. glabrata, and C. tropicalis with inhibition zone diameters of 20.9, 14.9, and 30.7 mm, respectively. The minimum inhibitory concentration of the S. aromaticum ethyl acetate extract was 250 µg/disc against C. tropicalis, and 500 µg/disc against C. albicans and C. glabrata, while the minimum fungicidal concentration was 0.5 mg/disc against C. tropicalis and 1 mg/disc against the C. albicans and C. glabrata. GC-MS analysis of the ethyl acetate extract revealed the main bioactive compound as eugenol (58.88%), followed by eugenyl acetate (23.86%), trans-caryophyllene (14.44%), and α-humulene (1.88%). The cytotoxicity assay indicated that the diethyl ether extract demonstrated the lowest toxicological effect against the HUH7 cell line, with a relative IC50 of 62.43 µg/ml; the methanolic extract demonstrated a higher toxicity (IC50, 24.17 µg/ml). CONCLUSION: As the S. aromaticum extract exhibited high antifungal activity at low concentrations, it can be a potential source of natural antifungal drugs.

Study of the activity of Punica granatum-mediated silver nanoparticles against Candida albicans and Candida glabrata, alone or in combination with azoles or polyenes.

The continuous emergence of Candida strains resistant to currently used antifungals demands the development of new alternatives that could reduce the burden of candidiasis. In this work silver nanoparticles synthesized using a green route are efficiently used, alone or in combination with fluconazole, amphotericin B or nystatine, to inhibit growth of C. albicans and C. glabrata oral clinical strains, including in strains showing resistance to fluconazole. A potent inhibitory effect over biofilm formation prompted by the two Candida species was also observed, including in mature biofilm cells. These results foster the use of phytotherapeutics as effective treatments in oral candidiasis.

Ethno-medicinal study of Artemisia ordosica Krasch. (traditional Chinese/Mongolian medicine) extracts for the treatment of allergic rhinitis and nasosinusitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia ordosica Krasch. (AOK) has been used for rheumatic arthritis, cold headache, sore throat, etc. in traditional Chinese/Mongolian medicine and is used for nasosinusitis by local Mongolian "barefoot" doctors. Up to now, their mechanisms are still unclear. AIM: To evaluate the in vivo anti-inflammatory and allergic rhinitis (AR) alleviating effect as well as in vitro antimicrobial activities of AOK extracts to verify its ethno-medicinal claims. MATERIALS AND METHODS: Crude extracts (methanol/95%-ethanol/ethyl acetate) of AOK root/stem/leaf and fractions (petroleum ether/ethyl acetate/n-butanol/aqueous) of AOK root extract were prepared. Xylene-induced ear swelling model in mouse and ovalbumin (OVA)-induced AR model in guinea pig were established. Ear swelling degrees of mice were measured. The numbers of rubbing movement and sneezes of guinea pigs were counted to evaluate the symptoms of AR. The serum levels of histamine, INF-γ, IL-2/4/10, and VCAM-1 were measured by ELISA assay. The histological changes of nasal mucosa were investigated by light microscope after H&E staining. Antimicrobial activities of AOK extracts were also tested. LC-MS/MS analysis was performed to characterize the constituents of active extract and molecular docking was conducted to predict the biological mechanism. RESULTS: In ear-swelling model, extract (100.00 mg/kg) from the ethyl acetate layer of 95% ethanol (100.00 mg/kg) showed better swelling inhibition in mice than positive control (dexamethasone, 191.91 mg/kg). In AR model, extract from the ethyl acetate layer of 95% ethanol significantly alleviated the AR symptoms in guinea pigs, decreased the serum levels of histamine, INF-γ, IL-2/4/10, and VCAM-1, and reduced the infiltration of eosinophil in nasal mucosa. For Staphylococcus aureus, the ethyl acetate extract of AOK stem showed the highest inhibition (MIC=1.25 mg/mL), for Escherichia coli, n-butanol layer of 95% ethanol extract of AOK root showed the highest inhibition (MIC=15.00 mg/mL), for Candida glabrata, 95%-ethyl acetate extract of AOK leaf showed the best inhibition (MIC=0.064 mg/mL), while ethyl acetate and n-butanol layers showed similar inhibition on MRSA (MIC=7.50 mg/mL). LC-MS/MS characterization showed that dicaffeoylquinic acids account for more than 30% of ethyl acetate layer of AOK extract. Dicaffeoylquinic acids bind with histamine-1 receptor with high affinities and interesting modes. CONCLUSIONS: Extracts from AOK had interesting anti-inflammatory activity in mice, alleviating effect against OVA-induced AR in guinea pigs, and antimicrobial activities in vitro, which support the ethno-medicinal use of it. The main constituents in ethyl acetate layer of AOK root extract are dicaffeoylquinic acids and could bind with histamine-1 receptor well. These findings highlighted the importance of natural product chemistry study of AOK.

Acquisition of FKS2 mutation after echinocandin treatment of infective endocarditis by Candida glabrata.

Bloodstream infections caused by non-albicans Candida species are increasing and echinocandins have been extensively used especially in patients with hemodynamic instability, previous antifungal treatment and hospital risk factors for intrinsic or acquired resistance to azoles. Candida glabrata resistance to echinocandins is reported and is generally associated with previous use of echinocandins; FKS gene mutations have been associated with a worse outcome. We report the case of a 65-year-old woman who developed candidemia and endocarditis by C. glabrata with a newly acquired FKS mutation 24 months after successful treatment of infective endocarditis by C. glabrata with a double dosage of anidulafungin (200 mg daily) followed by oral voriconazole. Driven by high echinocandin MICs the strain taken by intraoperative cultures was further analyzed in a referral microbiology laboratory, confirming the new onset of point mutation S633P of the FKS2 gene.

Amphotericin B Induction with Voriconazole Consolidation as Salvage Therapy for FKS-Associated Echinocandin Resistance in Candida glabrata Septic Arthritis and Osteomyelitis.

We report the case of a 61-year-old female with Crohn's disease dependent on total parenteral nutrition who developed a central venous catheter bloodstream infection and septic arthritis, complicated further by osteomyelitis and persistent Candida glabrata fungemia. Fluconazole treatment led to persistent infection, and micafungin therapy failed with development of FKS-associated resistance. Infection responded after initiation of amphotericin B plus voriconazole. Echinocandin resistance is increasingly recognized, suggesting a role for alternative antifungal therapies.

Clove oil nanoemulsion showed potent inhibitory effect against Candida spp.

Increasing resistance to current fungicides is a clinical problem that leads to the need for new treatment strategies. Clove oil (CO) has already been described as having antifungal action. However, it should not be applied directly to the skin as it may be irritating. One option for CO delivery and suitable topical application would be nanoemulsions (NEs). NEs have advantages such as decreased irritant effects and lower dose use. The purpose of this work was the development of NEs containing CO and in vitro evaluation against Candida albicans and Candida glabrata. The NEs were produced by an ultrasonic processor with different proportions of CO and Pluronic® F-127. In order to determine the best composition and ultrasound amplitude, an experimental design was performed. For the evaluation, droplet size and polydispersity index (PdI) were used. After the stability study, in vitro activity against C. albicans and C. glabrata was evaluated. NEs selected for the stability study, with diameter <40 nm and PdI <0.2, remained stable for 420 d. Activity against Candida spp. was improved when the CO was nanoemulsified, for it possibly leads to a better interaction between the active and the microorganisms, mainly in C. albicans.

Activity of base analogues (5-fluorouracil, 5-flucytosine) against planktonic cells and mature biofilm of Candida yeast. Effect of combination with folinic acid.

BACKGROUND: The increasing number of Candida infections, especially those caused by non-C. albicans species and resistant strains, is a serious medical problem. OBJECTIVES: In this study, the antifungal activity of base analogues, 5-flucytosine (5-FC) and 5-fluorouracil (5-FU), was tested against planktonic cells as well as against mature biofilm. METHODS: Tests were performed according the EUCAST methodology. Antibiofilm effectiveness of tested drugs was determined by the crystal violet staining method. The cytotoxicity assays was performed according to the ISO 10993-5 norm. RESULTS: 5-FC and 5-FU were effective against fifteen fluconazole resistant Candida glabrata strains with an average minimal inhibitory concentration (MIC) of 0.152mg/L and 0.39mg/L, respectively. Folinic acid (folinate- e.g., leucovorin) is a common drug used in oncology simultaneously with 5-FU. In our tests folinate was able to lower MIC for 5-FC from 0.152 to 0.058mg/L (P<0.05). In the biofilm assay 5-FU and 5-FC alone did not induce any changes in the biomass of mature biofilm. Addition of folinate to each base analogue resulted in up to 90% reduction of biomass. Viability tests show that a concentration of 64mg/L of 5-FC and 5-FU supplemented with folinate can be fungicidal against mature biofilms of some Candida isolates. No cytotoxic effect was found for combination of FOL and 5-FC. CONCLUSION: Therapy of 5-FU+folinate is well known in cancer treatment, in this study we reveal the beneficial effect of folinate on antifungal activity of 5-FC as well as the antifungal potential of 5-FU+folinate.

Species distribution and antifungal drug susceptibilities of yeasts isolated from the blood samples of patients with candidemia.

Candida albicans is the most frequently isolated fungal species in hospital settings worldwide. However, non-albicans Candida species with decreased susceptibility to antifungals have emerged as an important cause of fungemia. The aims of this study were to determine the species distribution of fungi isolated from the blood samples of patients at a Swedish University Hospital and to define the in vitro susceptibilities of these isolates to nine antifungal agents. In total, 233 yeast isolates from 143 patients were included in this study. Antifungal susceptibility testing was performed using broth dilution Sensititre YeastOne panels, which comprised amphotericin B, 5-flucytosine, fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, micafungin, and caspofungin. The most common species in all age groups was C. albicans (n = 93, 65%), followed by C. glabrata (n = 27, 19%) and C. parapsilosis (n = 15, 10%). C. glabrata was mostly found in elderly individuals, while C. parapsilosis was found mainly in young children (p = 0.008). Antifungal resistance was low in the Candida species, except for reduced susceptibility to fluconazole among C. glabrata strains. C. albicans is the most frequent colonizer of Swedish patients. In general antifungal resistance is uncommon in Candida species. Nevertheless, reduced susceptibilities to fluconazole and echinocandins were found in C. glabrata and C. parapsilosis, respectively.

In Vitro Activity of a Novel Antifungal Compound, MYC-053, against Clinically Significant Antifungal-Resistant Strains of Candida glabrata, Candida auris, Cryptococcus neoformans, and Pneumocystis spp.

An urgent need exists for new antifungal compounds to treat fungal infections in immunocompromised patients. The aim of the current study was to investigate the potency of a novel antifungal compound, MYC-053, against the emerging yeast and yeast-like pathogens Candida glabrata, Candida auris, Cryptococcus neoformans, and Pneumocystis species. MYC-053 was equally effective against the susceptible control strains, clinical isolates, and resistant strains, with MICs of 0.125 to 4.0 µg/ml. Notably, unlike other antifungals such as azoles, polyenes, and echinocandins, MYC-053 was effective against Pneumocystis isolates, therefore being the only synthetic antifungal that may potentially be used against Pneumocystis spp., Candida spp., and Cryptococcus spp. MYC-053 was highly effective against preformed 48-h-old C. glabrata and C. neoformans biofilms, with minimal biofilm eradication concentrations equal to 1 to 4 times the MIC. Together, these data indicated that MYC-053 may be developed into a promising antifungal agent for the treatment and prevention of invasive fungal infections caused by yeasts and yeast-like fungi.

The antifungal activity and mechanisms of action of quantified extracts from berries, leaves and roots of Phytolacca tetramera.

BACKGROUND: Phytolacca tetramera is an endemic plant from Argentina that is currently at serious risk because its environment is subjected to a high anthropic impact. A previous study has shown that berry extracts obtained from this plant display antifungal activity against multiple human-pathogenic fungi when tested with a non-standardized method. Further evidences of the antifungal properties of other parts of the plant and studies of mechanism of antifungal action of the antifungal chemically characterized extracts are required. PURPOSE: This study aimed to gain further evidence of the antifungal activity of P. tetramera berry, leaf and root extracts in order to find the most active extract to be developed as an Herbal Medicinal Antifungal Product. The medicinal usefulness of P. tetramera extracts as antifungal agents will serve as an important support to create concience and carry out actions tending to the preservation of this threatened species and its environment. MATERIALS AND METHODS: Chemical analysis of all P. tetramera extracts, including quantitation of selected markers, was performed through UHPLC-ESI-MS/MS and UPLC-ESI-MS techniques according to the European Medicines Agency (EMA). The antifungal activity of the quantified extracts was tested with the standardized CLSI microbroth dilution method against Candida spp. Antifungal mechanisms of the most active extract were studied by examination of morphological changes by phase-contrast and fluorescence microscopies and both, cellular and enzymatic assays targeting either the fungal membrane or the cell wall. RESULTS: The antifungal activity of twelve P. tetramera extracts was tested against Candida albicans and Candida glabrata. The dichloromethane extract from berries (PtDEb) showed the best activity. Phytolaccagenin (PhytG) and phytolaccoside B (PhytB) were selected as the main active markers for the antifungal P. tetramera extracts. The quantitation of these active markers in all extracts showed that PtDEb possessed the highest amount of PhytG and PhytB. Finally, studies on the mechanism of antifungal action showed that the most active PtDEb extract produces morphological changes compatible with a damage of the cell wall and/or the plasma membrane. Cellular and enzymatic assays showed that PtDEb would not damage the fungal cell wall by itself, but would alter the plasma membrane. In agreement, PtDEb was found to bind to ergosterol, the main sterol of the fungal plasma membrane. CONCLUSION: Studies of the anti-Candida activity of P. tetramera extracts led to the selection of PtDEb as the most suitable extract, confirming the antifungal properties of the threatened species P. tetramera. The new data give a valuable reason for the definitive protection of this sp. and its natural environment thus allowing further studies for the future development of an Herbal Medicinal Antifungal Product.

Comparative Genomics of Serial Candida glabrata Isolates and the Rapid Acquisition of Echinocandin Resistance during Therapy.

The opportunistic pathogen Candida glabrata shows a concerning increase in drug resistance. Here, we present the analysis of two serial bloodstream isolates, obtained 12 days apart. Both isolates show pan-azole resistance and echinocandin resistance was acquired during the sampling interval. Genome sequencing identified nine nonsynonymous SNVs between the strains, including a S663P substitution in FKS2 and previously undescribed SNVs in MDE1 and FPR1, offering insight into how C. glabrata acquires drug resistance and adapts to a human host.

In Vitro Antimicrobial Activities of Commercially Available Tea Tree (Melaleuca alternifolia) Essential Oils.

Melaleuca alternifolia tea tree oil (TTO) is largely used in cutaneous infections. Clinical observations reported antibacterial, antifungal, and antiviral activities, whereas in vitro experiments ascribed most of biological properties to terpinen-4-ol. Since different plant chemotypes and storage conditions result in variations of chemical composition of commercially available TTO, in this study we investigated the antimicrobial activity and the chemical profile of ten commercially available TTO products. The antimicrobial activity was assessed against Candida glabrata, Herpes simplex virus type 1 (HSV-1), methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa grown in planktonic mode or biofilms. Only five out of ten TTO batches reported significant antimicrobial activity. The identified TTO products reduced bacterial survival in biofilms, generated oxidative damage in C. glabrata, and diminished HSV-1 infectivity. GC-MS analysis revealed that all the analyzed TTO batches fitted into the terpinen-4-ol chemotype even if we reported great variability in composition of nine major ISO-specified TTO components. Overall, we were not able to ascribe the antimicrobial activity to the content in terpinen-4-ol. We therefore conclude that the antimicrobial activity of TTO results from complex interaction among different components.

Do raspberry extracts and fractions have antifungal or anti-adherent potential against Candida spp.?

Candida spp., especially Candida albicans, is one of the main colonisers of the oral cavity. Due to its ability to form biofilms, it can be implicated in dental caries, periodontal disease and denture stomatitis. Microbial cells in biofilms are minimally impacted by conventional drugs. The aim of this study was to find new substances able to inhibit the adhesion of Candida spp. in order to prevent biofilm formation in the oral cavity. This study focused on the red raspberry (Rubus idaeus) fruit, known for its richness in potentially antimicrobial tannins. Extraction with a polarity gradient was performed on acetone extracts from frozen ripe and unripe fruits, resulting in eight extracts. The antifungal and anti-adhesion effects of the extracts were determined using broth microdilution and XTT methods, respectively, against C. albicans, Candida glabrata and Candida parapsilosis strains. Interestingly, four extracts (hexane and ethyl acetate) displayed anti-adhesion activity against C. albicans at low concentrations [50% inhibitory concentration (IC50) 15.6-62.5 µg/mL]. Bioassay-guided fractionation by chromatographic methods of the most active extract obtained from ripe fruit (ethyl acetate extract) led to two subfractions enriched in anti-adhesion compounds, identified by mass spectrometry analysis as hydrolysable and condensed tannins. Their activities were dose-dependent with maximum inhibition at 80% (IC50 = 25 µg/mL and 12.5 µg/mL). Regarding antifungal activity, no extract was active against planktonic cells of the tested strains. This work highlights for the first time the potential of raspberries to prevent oral C. albicans biofilms.

Phytochemical analysis and mode of action against Candida glabrata of Paeonia emodi extracts.

In the present study, we have evaluated the antifungal activity of the seed, root and leaf of Paeonia emodi (commonly known as Himalayan peony) in four common solvents (acetone, chloroform, methanol and water) against six fungal strains. The methanolic seed extract (MSE) showed promising antifungal activity against Candida albicans (6.25mg/mL), Candida glabrata (3.12mg/mL) and Candida parapsilosis (12.50mg/mL) among all the fungal strains tested. Combination of the MSE with the well-known commercial antifungal drugs amphotericin B (Amp B), nystatin (NYS) and fluconazole (FLC) resulted in the killing of C. glabrata at non-inhibitory concentrations, i.e., 0.35µg/mL for Amp B, 0.55µg/mL for NYS and 1.19µg/mL for FLC. Notably, MSE caused cell wall damage of C. glabrata cells, as confirmed by confocal microscopy, flowcytometry and scanning electron microscopy (SEM). The MSE was fractionated by thin layer chromatography (TLC). TLC-bioautography was used to determine the active compounds present in the MSE. Column chromatography was used to separate the potential active compounds from the MSE. Furthermore, gas chromatography-mass spectrometry (GC-MS) andfourier-transform infrared spectroscopy (FTIR) were used to identify the phytocomponents of the MSE. These experiments revealed 13-docosenamide/9-octadecenamide/trans-13-docosenamide (89.70%) as being the predominant compound using a chloroform/methanol solvent system for the separation. Interestingly, the MSE also exhibited less significant cytotoxicity at the minimum inhibitory concentration (MIC) against mammalian cells (HeLa and HEK293). This study suggests that the MSE of P. emodi can be used for the treatment of C. glabrata infection.

Antifungal activity of essential oils against azole-resistant and azole-susceptible vaginal Candida glabrata strains.

Candida glabrata is an opportunistic pathogen, associated with endocarditis, meningitis, and disseminated disease, and also with complicated vaginitis. Essential oils derived from aromatic plants are known in traditional medicine as antimicrobial agents and have antifungal properties. The aim of this work was to evaluate whether 12 tested essential oils (tea tree, laurel, anise, basil, bergamot, lavender, mint, oregano, grapefruit, rosemary, winter savory, and ginger) could have a transverse effect on C. glabrata sensitive strains but above all on strains resistant to the three main azole antifungals used (clotrimazole, fluconazole, itraconazole). For this reason, different strains of C. glabrata, vaginal isolated, were characterized (disk diffusion assay, minimal inhibitory concentration) with respect to their response to such antifungals. Electron microscopy analyses were performed to examine cellular damages in depth. Subsequently, we wanted to evaluate the effect of the oils on human cells to estimate their potential cytotoxicity. Oregano and winter savory were the two most effective essential oils, inducing growth inhibition, cell damage of C. glabrata strains (both sensitive and resistant to azole antifungal drugs), and medium-high level of toxicity against human keratinocytes. The results of this work support the research for new alternatives or complementary therapies against vaginal candidiasis.

Voriconazole Treatment for an Infant With Intractable Candida glabrata Meningitis.

We report voriconazole levels in an infant with disseminated Candida glabrata infection who received combination antifungal therapy and rescue voriconazole treatment. Serum and cerebrospinal fluid voriconazole levels were higher than anticipated and above target. Dose reduction did not lead to a reduction in the blood or cerebrospinal fluid levels. The patient did not exhibit identifiable drug toxicity.