Antifungal activity of Cinnamaldehyde derivatives against fluconazole-resistant Candida albicans.

BACKGROUND: Candida albicans is an opportunistic pathogen commonly found in human mucous membranes. In light of the escalating challenge posed by antibiotic resistance of C. albicans strains worldwide, it is an urgently necessary to explore alternative therapeutic options. OBJECTIVE: This study aims to assess the efficacy of two Cinnamaldehyde derivatives, 2-Cl Cinnamaldehyde (2-Cl CA) and 4-Cl Cinnamaldehyde (4-Cl CA), against C. albicans through both in vitro experiments and in vivo murine models and to evaluate their potential as new drug candidates for treating C. albicans. METHODS AND RESULTS: The minimum inhibitory concentrations (MICs) of Cinnamaldehyde 2-Cl and 4-Cl benzene ring derivatives against C. albicans were 25 µg/mL. Time-killing experiments revealed that both Cinnamaldehyde derivatives exhibited fungicidal activity against C. albicans at concentrations of 5 MIC and 10 MIC. In the checkerboard experiment, 4-Cl CA did not show any antagonistic effect when combined with first-line antifungal drugs. Instead, it exhibited additive effects in combination with nystatin. Both 2-Cl and 4-Cl CA demonstrated inhibitory activity against C. albicans biofilm formation, especially at 8 MIC and 16 MIC concentrations. In C. albicans biofilm eradication experiments, although high drug concentrations of 2-Cl and 4-Cl CA were unable to eradicate the biofilm completely, they were still effective in killing C. albicans cells within the biofilm. Moreover, sub-inhibitory concentrations of 4-Cl CA (ranging from 5 to 20 µg/mL) significantly inhibited cell aggregation and hyphal formation. Furthermore, 4-Cl CA effectively inhibited intracellular C. albicans infection in macrophages. Lastly, the effectiveness of 4-Cl CA was evaluated in a mouse model of hematogenous disseminated candidiasis caused by C. albicans, which revealed that 4-Cl CA significantly reduced fungal burden and improved mouse survival compared to the untreated controls. CONCLUSION: The 4-Cl CA exhibited inhibitory effects against C. albicans through both in vivo and in vitro models, demonstrating its therapeutic potential as a promising new drug candidate for treating drug-resistant candidiasis albicans.

Fluconazole-resistant Candida parapsilosis: fast detection of the Y132F ERG11p substitution, and a proposed microsatellite genotyping scheme.

OBJECTIVES: We propose fast and accurate molecular detection of the Y132F ERG11p substitution directly on pure-cultured Candida parapsilosis isolates. We also assessed a discriminative genotyping scheme to track circulating genotypes. METHODS: A total of 223 C. parapsilosis isolates (one patient each) from 20 hospitals, located in Spain and Italy were selected. Isolates were fluconazole-resistant (n = 94; harbouring the Y132F ERG11p substitution [n = 85], the G458S substitution [n = 6], the R398I substitution [n = 2], or the wild-type ERG11 gene sequence) or fluconazole-susceptible (n = 129). Two targeted-A395T-mutation PCR formats (conventional and real-time) were engineered and optimized on fluconazole-susceptible and fluconazole-resistant pure-cultured isolates, thus skipping DNA extraction. Two genotyping schemes were compared: Scheme 1 (CP1, CP4a, CP6, and B markers), and Scheme 2 (6A, 6B, 6C, CP1, CP4a, and CP6 markers). RESULTS: The screening performed using both PCR formats showed 100% specificity (fluconazole-susceptible isolates; n = 129/129) and sensitivity (Y132F isolates; n = 85/85) values; however, results were available in 3 and 1.5 hours with the conventional and real-time PCR formats, respectively. Overall, Scheme 1 showed higher genetic diversity than Scheme 2, as shown by the number of alleles detected (n = 98; mean 23, range 13-38), the significantly higher observed and expected heterozygosity, and the probability of identity index (2.5 × 10-6). Scheme 2 markers did not provide further genotypic discrimination of Y132F fluconazole-resistant genotypes. CONCLUSION: Both proposed PCR formats allow us to speed up the accurate detection of substitution Y132F ERG11p in C. parapsilosis isolates with 100% specificity and sensitivity. In addition, we recommend CP1, CP4a, CP6, and B microsatellite markers for genotyping fluconazole-resistant isolates.

Increase in candidemia cases and emergence of fluconazole-resistant Candida parapsilosis and C. auris isolates in a tertiary care academic hospital during the COVID-19 pandemic, Greece, 2020 to 2023.

BackgroundThe COVID-19 pandemic and the emergence of Candida auris have changed the epidemiological landscape of candidaemia worldwide.AimWe compared the epidemiological trends of candidaemia in a Greek tertiary academic hospital before (2009-2018) and during the early COVID-19 (2020-2021) and late COVID-19/early post-pandemic (2022-2023) era.MethodsIncidence rates, species distribution, antifungal susceptibility profile and antifungal consumption were recorded, and one-way ANOVA or Fisher's exact test performed. Species were identified by MALDI-ToF MS, and in vitro susceptibility determined with CLSI M27-Ed4 for C. auris and the EUCAST-E.DEF 7.3.2 for other Candida spp.ResultsIn total, 370 candidaemia episodes were recorded during the COVID-19 pandemic. Infection incidence (2.0 episodes/10,000 hospital bed days before, 3.9 during the early and 5.1 during the late COVID-19 era, p < 0.0001), C. auris (0%, 9% and 33%, p < 0.0001) and fluconazole-resistant C. parapsilosis species complex (SC) (20%, 24% and 33%, p = 0.06) infections increased over time, with the latter not associated with increase in fluconazole/voriconazole consumption. A significant increase over time was observed in fluconazole-resistant isolates regardless of species (8%, 17% and 41%, p < 0.0001). Resistance to amphotericin B or echinocandins was not recorded, with the exception of a single pan-echinocandin-resistant C. auris strain.ConclusionCandidaemia incidence nearly tripled during the COVID-19 era, with C. auris among the major causative agents and increasing fluconazole resistance in C. parapsilosis SC. Almost half of Candida isolates were fluconazole-resistant, underscoring the need for increased awareness and strict implementation of infection control measures.

Antifungal bioactivity of Sarcococca hookeriana var. digyna Franch. against fluconazole-resistant Candida albicans in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Sarcococca hookeriana var. digyna Franch. has been widely utilized in folk medicine by the Miao people in the southwestern region of China for treating skin sores which may be associated with microbial infection. AIM OF THE STUDY: To investigate the antifungal bioactivity of S. hookeriana var. digyna against fluconazole-resistant Candida albicans in vitro and in vivo, as well as its underlying mechanism and the key bioactive component. MATERIALS AND METHODS: The antifungal bioactivity of 80% ethanol extract of S. hookeriana var. digyna (SHE80) was investigated in vitro using the broth microdilution method, time-growth curve, and time-kill assay. Its key functional component and antifungal mechanism were explored with combined approaches including UPLC-Q-TOF-MS, network pharmacology and metabolomics. The antifungal pathway was further supported via microscopic observation of fungal cell morphology and examination of its effects on fungal biofilm and cell membranes using fluorescent staining reagents. In vivo assessment of antifungal bioactivity was conducted using a mouse model infected with C. albicans on the skin. RESULTS: S. hookeriana var. digyna suppressed fluconazole-resistant C. albicans efficiently (MIC = 16 µg/mL, MFC = 64 µg/mL). It removed fungal biofilm, increased cell membrane permeability, induced protein leakage, reduced membrane fluidity, disrupted mitochondrial membrane potential, induced the release of reactive oxygen species, promoted cell apoptosis, and inhibited the transformation of fungi from the yeast state to the hyphal state significantly. In terms of mechanism, it affected sphingolipid metabolism and signaling pathway. Moreover, the predicted bioactive component, sarcovagine D, was supported by antifungal bioactivity evaluation in vitro (MIC = 4 µg/mL, MFC = 16 µg/mL). Furthermore, S. hookeriana var. digyna promoted wound healing, reduced the number of colony-forming units, and reduced inflammation effectively in vivo. CONCLUSIONS: The traditional use of S. hookeriana var. digyna for fungal skin infections was supported by antifungal bioactivity investigated in vitro and in vivo. Its mechanism and bioactive component were predicted and confirmed by experiments, which also provided a new antifungal agent for future research.

Activity and mechanism of action of antimicrobial peptide ACPs against Candida albicans.

AIMS: Candida albicans is the most prevalent pathogenic fungus, exhibiting escalating multidrug resistance (MDR). Antimicrobial peptides (AMPs) represent promising candidates for addressing this issue. In this research, five antimicrobial peptides, ACP1 to ACP5 which named ACPs were studied as alternative fungicidal molecules. MAIN METHODS: CD assay was used to analyze the 2D structures, Absorbance method was used to test the antimicrobial activity, haemolytic activity, time-kill kinetics, biofilm inhibition and reduction activity, resistance induction activity and assessment against fluconazole-resistant C. albicans. SEM, TEM, CLSM, flow cytometer and FM were carried out to provide insight into the mechanisms of anti-Candida action. KEY FINDINGS: ACPs possessed an α-helical structure and strong anti-Candida activities, with minimum inhibitory concentrations (MICs) from 3.9 to 15.6 µg/mL. In addition, ACPs did not produce hemolysis at concentrations lower than 10 or 62 × MIC, indicating their low cytotoxicity. Fungicidal kinetics showed that they completely killed C. albicans within 8 h at 2 to 4 × MIC. Notably, ACPs were highly fungicidal against fluconazole-resistant C. albicans and showed low resistance. In addition, they were effective in inhibiting mycelium and biofilm formation. Fluorescence microscopy revealed that while fluconazole had minimal to no inhibitory effect on biofilm-forming cells, ACPs induced apoptosis in all of them. The research on mechanism of action revealed that ACPs disrupted the cell membranes, with ROS increasing and cellular mitochondrial membrane potential decreasing. SIGNIFICANCE: ACPs could be promising candidates for combating fluconazole-resistant C. albicans infections.

Synthesis, structure-activity relationship and biological evaluation of indole derivatives as anti-Candida albicans agents.

In this work, we synthesized a series of indole derivatives to cope with the current increasing fungal infections caused by drug-resistant Candida albicans. All compounds were evaluated for antifungal activities against Candida albicans in vitro, and the structure-activity relationships (SARs) were analyzed. The results indicated that indole derivatives used either alone or in combination with fluconazole showed good activities against fluconazole-resistant Candida albicans. Further mechanisms studies demonstrated that compound 1 could inhibit yeast-to-hypha transition and biofilm formation of Candida albicans, increase the activity of the efflux pump, the damage of mitochondrial function, and the decrease of intracellular ATP content. In vivo studies, further proved the anti-Candida albicans activity of compound 1 by histological observation. Therefore, compound 1 could be considered as a novel antifungal agent.

A mechanism study on the synergistic effects of rifapentine and fluconazole against fluconazole-resistant Candida albicans in vitro.

Candida albicans (C. albicans) is one of the most common clinical isolates of systemic fungal infection. Long-term and inappropriate use of antifungal drugs can cause fungal resistance, which poses a great challenge to the clinical treatment of fungal infections. The combination of antifungal drugs and non-antifungal drugs to overcome the problem of fungal resistance has become a research hotspot in recent years. Our previous study found that the combination of rifapentine (RFT) and fluconazole (FLC) has a significant synergistic against FLC-resistant C. albicans. The present study aimed to further verify the synergistic effect between FLC and RFT against the FLC-resistant C. albicans 100, and explore the underlying mechanism. The growth curve and spot assay test not only showed the synergistic effect of FLC and RFT on FLC-resistant C. albicans in vitro but exhibited a dose-dependent effect on RFT, indicating that RFT may play a principal role in the synergic effect of the two drugs. Flow cytometry showed that the combined use of RFT and FLC arrested cells in the G2/M phase, inhibiting the normal division and proliferation of FLC-resistant C. albicans. Transmission electron microscopy (TEM) demonstrated that FLC at a low concentration could still cause a certain degree of damage to the cell membrane in the FLC-resistant C. albicans, as represented by irregular morphologic changes and some defects observed in the cell membrane. When FLC was used in combination with RFT, the nuclear membrane was dissolved and the nucleus was condensed into a mass. Detection of the intracellular drug concentration of fungi revealed that the intracellular concentration of RFT was 31-195 fold that of RFT alone when it was concomitantly used with FLC. This indicated that FLC could significantly increase the concentration of RFT in cells, which may be due to the damage caused to the fungal cell membrane by FLC. In short, the present study revealed a synergistic mechanism in the combined use of RFT and FLC, which may provide a novel strategy for the clinical treatment of FLC-resistant C. albicans.

The anti-staphylococcal fusidic acid as an efflux pump inhibitor combined with fluconazole against vaginal candidiasis in mouse model.

BACKGROUND: Candida albicans is the most common fungus that causes vaginal candidiasis in immunocompetent women and catastrophic infections in immunocompromised patients. The treatment of such infections is hindered due to the increasing emergence of resistance to azoles in C. albicans. New treatment approaches are needed to combat candidiasis especially in the dwindled supply of new effective and safe antifungals. The resistance to azoles is mainly attributed to export of azoles outside the cells by means of the efflux pump that confers cross resistance to all azoles including fluconazole (FLC). OBJECTIVES: This study aimed to investigate the possible efflux pump inhibiting activity of fusidic acid (FA) in C. albicans resistant isolates and the potential use of Fusidic acid in combination with fluconazole to potentiate the antifungal activity of fluconazole to restore its activity in the resistant C. albicans isolates. METHODS: The resistance of C. albicans isolates was assessed by determination of minimum inhibitory concentration. The effect of Fusidic acid at sub-inhibitory concentration on efflux activity was assayed by rhodamine 6G efflux assay and intracellular accumulation. Mice model studies were conducted to evaluate the anti-efflux activity of Fusidic acid and its synergistic effects in combination with fluconazole. Impact of Fusidic acid on ergosterol biosynthesis was quantified. The synergy of fluconazole when combined with Fusidic acid was investigated by determination of minimum inhibitory concentration. The cytotoxicity of Fusidic acid was tested against erythrocytes. The effect of Fusidic acid on efflux pumps was tested at the molecular level by real-time PCR and in silico study. In vivo vulvovaginitis mice model was used to confirm the activity of the combination in treating vulvovaginal candidiasis. RESULTS: Fusidic acid showed efflux inhibiting activity as it increased the accumulation of rhodamine 6G, a substrate for ABC-efflux transporter, and decreased its efflux in C. albicans cells. The antifungal activity of fluconazole was synergized when combined with Fusidic acid. Fusidic acid exerted only minimal cytotoxicity on human erythrocytes indicating its safety. The FA efflux inhibitory activity could be owed to its ability to interfere with efflux protein transporters as revealed by docking studies and downregulation of the efflux-encoding genes of both ABC transporters and MFS superfamily. Moreover, in vivo mice model showed that using fluconazole-fusidic acid combination by vaginal route enhanced fluconazole antifungal activity as shown by lowered fungal burden and a negligible histopathological change in vaginal tissue. CONCLUSION: The current findings highlight FA's potential as a potential adjuvant to FLC in the treatment of vulvovaginal candidiasis.

Fluconazole-resistant Candida parapsilosis complex candidemia and analysis of mutations in the ERG11 gene from Pakistan.

BACKGROUND: Recent reports of the emergence of fluconazole resistance in Candida parapsilosis species complex poses a challenge, more specifically in settings where echinocandin-based treatment regime is not feasible. OBJECTIVE: This study reported emergence of fluconazole resistance in C. parapsilosis species complex strains isolated from blood cultures. MATERIALS AND METHODS: This retrospective observational study was conducted from 2018 to 2020 at a tertiary care laboratory from Pakistan. Fluconazole-resistant C. parapsilosis species complex fungemia cases were identified from laboratory database and clinical details were collected. Identification of C. parapsilosis species complex was done using API 20C AUX and Cornmeal Tween80 agar morphology. Minimum inhibitory concentrations (MICs) were determined using Sensititre YeastONE and interpretation was done with CLSI M60 ED1:2017. ERG11 gene region was amplified and sequenced by Sanger sequencing and analysed by MEGA 11 Software. RESULTS: A total of 13 (8.5%) fluconazole-resistant isolates were identified from 152 C. parapsilosis species complex candidemia cases. Fluconazole MICs of resistant isolates ranged between 8 and 256 µg/mL. Analysis of ERG11 gene revealed nonsynonymous mutations at position Y132F in 86% of the fluconazole-resistant isolates. Diabetes and hospitalization were important risk factors for candidemia with fluconazole-resistant C. parapsilosis complex. CONCLUSION: This is the first report of the emergence and molecular mechanisms of fluconazole resistance in C. parapsilosis species complex from Pakistan. Y132F mutation in the ERG11 gene was the most common mutation in fluconazole-resistant strains. These findings are concerning and necessitate better diagnostics, newer antifungals, ongoing surveillance and further insights on resistance mechanisms in the country.

Invasive Candida infection: epidemiology, clinical and therapeutic aspects of an evolving disease and the role of rezafungin.

INTRODUCTION: Invasive Candida Infections (ICIs) have undergone a series of significant epidemiological, pathophysiological, and clinical changes during the last decades, with a shift toward non-albicans species, an increase in the rate of exogenous infections and clinical manifestations ranging from candidemia to an array of highly invasive and life-threatening clinical syndromes. The long-acting echinocandin rezafungin exhibits potent in-vitro activity against most wild-type and azole-resistant Candida spp. including C.auris. AREAS COVERED: The following topics regarding candidemia only and ICIs were reviewed and addressed: i) pathogenesis; ii) epidemiology and temporal evolution of Candida species; iii) clinical approach; iv) potential role of the novel long-acting rezafungin in the treatment of ICIs. EXPERT OPINION: Authors' expert opinion focused on considering the potential role of rezafungin in the evolving context of ICIs. Rezafungin, which combines a potent in-vitro activity against Candida species, including azole-resistant strains and C.auris, with a low likelihood of drug-drug interactions and a good safety profile, may revolutionize the treatment of candidemia/ICI. Indeed, it may shorten the length of hospital stays when clinical conditions allow and extend outpatient access to treatment of invasive candidiasis, especially when prolonged treatment duration is expected.

[Chemical constituents from Paris rugosa rhizomes and their antimicrobial activities].

Paris rugosa(Melanthiaceae) only grows in Yunnan province of China at present, and its chemical constituents have not been systematically studied. In this study, nine compounds, including one new compound pariposide G(1) and eight known compounds of cerin(2), stigmast-4-en-3-one(3), ß-ecdysone(4), ophiopogonin C'(5), methyl protogracillin(6), gracillin(7), parissaponin H(8), and parisyunnanoside G(9), were isolated and identified from the ethanol extract of P. rugosa rhizomes by column chromatography methods and semi-preparative high-performance liquid chromatography(HPLC). Compounds 1-9 were isolated from this plant for the first time. The antibacterial and antifungal activities of all the compounds were evaluated. The results showed that ophiopogonin C' had strong inhibitory effects on Candida albicans [MIC_(90)=(4.68±0.01) µmol·L~(-1)] and the fluconazole-resistant strain of C. albicans [MIC_(90)=(4.66±0.02) µmol·L~(-1)].

Withania somnifera seed oil exhibits antibiofilm properties against drug-resistant Candida auris clinical isolate through modulation in cell permeability.

AIM: Candida auris, fast evolving drug-resistant fungus, poses an imminent global health threat. Alternative drug-resistance nonevoking treatment options are necessary. This study explored the antifungal and antibiofilm efficacies of Withania somnifera seed oil extracted using super critical CO2 (WSSO) against clinically isolated Fluconazole-resistant C. auris and its putative mode-of-action. METHODS AND RESULTS: Effects of WSSO on C. auris were tested by broth microdilution method, with observed IC50 at 5.96 mg ml-1. Time-kill assay revealed that WSSO is fungistatic. Mechanistically, ergosterol binding and sorbitol protection assays showed that C. auris cell membrane and cell wall are the targets for WSSO. Lactophenol: Cotton-Blue: Trypan-Blue staining confirmed loss of intracellular contents by WSSO treatment. Candida auris biofilm formation was disrupted by WSSO (BIC50: 8.52 mg ml-1). Additionally, WSSO exhibited dose and time-dependent mature biofilm eradication property with 50% efficacies at 23.27, 19.28, 18.18, and 7.22 mg ml-1 over 24, 48, 72, and 96 h, respectively. Biofilm eradication by WSSO was further substantiated through scanning electron microscopy. Standard-of-Care Amphotericin B, at its break-point concentration, (2 µg ml-1) was found to be inefficient as an antibiofilm agent. CONCLUSIONS: WSSO is a potent antifungal agent effective against planktonic C. auris and its biofilm.

Arthrocolins Synergizing with Fluconazole Inhibit Fluconazole-Resistant Candida albicans by Increasing Riboflavin Metabolism and Causing Mitochondrial Dysfunction and Autophagy.

Our previous study reported that seminaturally occurring arthrocolins A to C with unprecedented carbon skeletons could restore the antifungal activity of fluconazole against fluconazole-resistant Candida albicans. Here, we showed that arthrocolins synergized with fluconazole, reducing the fluconazole minimum and dramatically augmenting the survivals of 293T human cells and nematode Caenorhabditis elegans infected with fluconazole-resistant C. albicans. Mechanistically, fluconazole can induce fungal membrane permeability to arthrocolins, leading to the intracellular arthrocolins that were critical to the antifungal activity of the combination therapy by inducing abnormal cell membranes and mitochondrial dysfunctions in the fungus. Transcriptomics and reverse transcription-quantitative PCR (qRT-PCR) analysis indicated that the intracellular arthrocolins induced the strongest upregulated genes that were involved in membrane transports while the downregulated genes were responsible for fungal pathogenesis. Moreover, riboflavin metabolism and proteasomes were the most upregulated pathways, which were accompanied by inhibition of protein biosynthesis and increased levels of reactive oxygen species (ROS), lipids, and autophagy. Our results suggested that arthrocolins should be a novel class of synergistic antifungal compounds by inducing mitochondrial dysfunctions in combination with fluconazole and provided a new perspective for the design of new bioactive antifungal compounds with potential pharmacological properties. IMPORTANCE The prevalence of antifungal-resistant Candida albicans, which is a common human fungal pathogen causing life-threatening systemic infections, has become a challenge in the treatment of fungal infections. Arthrocolins are a new type of xanthene obtained from Escherichia coli fed with a key fungal precursor toluquinol. Different from those artificially synthesized xanthenes used as important medications, arthrocolins can synergize with fluconazole against fluconazole-resistant Candida albicans. Fluconazole can induce the fungal permeability of arthrocolins into fungal cells, and then the intracellular arthrocolins exerted detrimental effects on the fungus by inducing fungal mitochondrial dysfunctions, leading to dramatically reduced fungal pathogenicity. Importantly, the combination of arthrocolins and fluconazole are effective against C. albicans in two models, including human cell line 293T and nematode Caenorhabditis elegans. Arthrocolins should be a novel class of antifungal compounds with potential pharmacological properties.

Study on the mechanisms of action of berberine combined with fluconazole against fluconazole-resistant strains of Talaromyces marneffei.

Talaromyces (Penicillium) marneffei (T. marneffei) is a thermally dimorphic fungus that can cause opportunistic systemic mycoses. Our previous study demonstrated that concomitant use of berberine (BBR) and fluconazole (FLC) showed a synergistic action against FLC-resistant T. marneffei (B4) in vitro. In this paper, we tried to figure out the antifungal mechanisms of BBR and FLC in T. marneffei FLC-resistant. In the microdilution test, the minimum inhibitory concentration (MIC) of FLC was 256 µg/ml before FLC and BBR combination, and was 8 µg/ml after combination, the partial inhibitory concentration index (FICI) of B4 was 0.28. After the treatments of BBR and FLC, the studies revealed that (i) increase reactive oxygen species (ROS), (ii) reduce ergosterol content, (iii) destroy the integrity of cell wall and membrane, (iv) decrease the expression of genes AtrF, MDR1, PMFCZ, and Cyp51B however ABC1 and MFS change are not obvious. These results confirmed that BBR has antifungal effect on T. marneffei, and the combination with FLC can restore the susceptibility of FLC-resistant strains to FLC, and the reduction of ergosterol content and the down-regulation of gene expression of AtrF, Mdr1, PMFCZ, and Cyp51B are the mechanisms of the antifungal effect after the combination, which provides a theoretical basis for the application of BBR in the treatment of Talaromycosis and opens up new ideas for treatment of Talaromycosis.

Treatment of Recurrent Vulvovaginal Candidiasis With Ibrexafungerp.

Recurrent vulvovaginal candidiasis is a common disorder which causes significant morbidity among women worldwide, and treatment options are limited. Ibrexafungerp is a novel antifungal agent which was approved in 2021 for treatment of vulvovaginal candidiasis. We present a case of recurrent vulvovaginal candidiasis successfully treated with ibrexafungerp.

Design, synthesis, and evaluation of novel 3,4-isoxazolediamide derivatives for the combination treatment of azole-resistant candidiasis.

Invasive fungal infections are emerging as serious infectious diseases worldwide. Due to the frequent emergence of resistance, the cure for invasive fungal infections is often unachievable. The molecular chaperone Hsp90 provides a promising target because it supports survival, virulence, and drug resistance in a variety of pathogens. Herein, we report on the structural optimization and structure-activity relationship studies of 3,4-isoxazolediamide analogs. As a new class of fungal Hsp90 inhibitor, compound B25 was found to have good synergistic effects with fluconazole and to avoid potential mammalian toxicity. It also showed remarkable metabolic stability in vitro. Collectively, B25 could be a promising lead compound for drug discovery targeting fungal Hsp90 and deserves further investigation.

Synthesis and in vitro synergistic antifungal activity of analogues of Panax stipulcanatus saponin against fluconazole-resistant Candida albicans.

Oleanolic acid 3-O-ß-d-glucopyranosyl-(1 â†’ 3)-ß-d-glucopyranoside (1) and oleanolic acid 3-O-ß-d-glucopyranosyl-(1 â†’ 3)-[α-l-arabinofuranosyl-(1 â†’ 4)]-ß-d-glucopyranoside (2), novel Panax stipulcanatus saponin analogues, were synthesized for the first time starting from commercially available oleanolic acid, d-glucose, and L-(+)-arabinose. Glycosyl N-phenyltrifluoroacetimidates as donors and two-step consecutive glycosylation reactions are crucial in the synthesis. In vitro antifungal activity results indicated that analogue 2 combined with fluconazole showed synergistic antifungal activity against fluconazole-resistant Candida albicans, with MIC50 values 31.80 µg/mL and FICI values 0.32. We also found that intermediate compounds 16 and 17 revealed synergistic antifungal activity against susceptible Candida albicans when combined with fluconazole, with MIC50 values 1.43 µg/mL and 1.59 µg/mL, FICI values 0.29 and 0.32, respectively.

Antifungal Effects and Potential Mechanisms of Benserazide Hydrochloride Alone and in Combination with Fluconazole Against Candida albicans.

PURPOSE: The resistance of C. albicans to traditional antifungal drugs brings a great challenge to clinical treatment. To overcome the resistance, developing antifungal agent sensitizers has attracted considerable attention. This study aimed to determine the anti-Candida activity of BEH alone or BEH-FLC combination and to explore the underlying mechanisms. MATERIALS AND METHODS: In vitro antifungal effects were performed by broth microdilution assay and XTT reduction assay. Infected Galleria mellonella larvae model was used to determine the antifungal effects in vivo. Probes Fluo-3/AM, FITC-VAD-FMK and rhodamine 6G were used to study the influence of BEH and FLC on intracellular calcium concentration, metacaspase activity and drug efflux of C. albicans. RESULTS: BEH alone exhibited obvious antifungal activities against C. albicans. BEH plus FLC not only showed synergistic effects against planktonic cells and preformed biofilms within 8 h but also enhanced the antifungal activity in infected G. mellonella larvae. Mechanistic studies indicated that antifungal effects of drugs might be associated with the increasement of calcium concentration, activation of metacaspase activity to reduce virulence and anti-biofilms, but were not related to drug efflux. CONCLUSION: BEH alone or combined with FLC displayed potent antifungal activity both in vitro and in vivo, and the underlying mechanisms were related to reduced virulence factors.

First fluconazole-resistant Candida auris isolated from fungal otitis in Iran.

BACKGROUND AND PURPOSE: Candida auris, as a new characterized pathogenic yeast, has attracted remarkable attention in the recent decade due to its rapid global emergence and multidrug resistance traits. This unique species is able to cause nosocomial outbreaks and tolerate adverse conditions; however, it has been mostly misidentified by conventional methods. CASE REPORT: This report aimed to describe the first fluconazole-resistant case of C. auris otitis in an immunocompetent patient in Iran. The isolate showed minimum inhibitory concentration of ≥ 32 µg/ml for fluconazole; however, the patient was treated with topical clotrimazole and miconazole with no recurrence. CONCLUSION: This was the second strain of C. auris isolated from otitis in Iran which was fluconazole-resistant, unlike the first Iranian isolate.

Effectiveness of antimicrobial photodynamic therapy with indocyanine green against the standard and fluconazole-resistant Candida albicans.

Antimicrobial photodynamic therapy (aPDT) is an alternative approach. The current study aimed to investigate the efficacy of aPDT with indocyanine green (ICG) against two Candida albicans (C. albicans) strains. In this in vitro study, the inoculum of standard ATCC 10,231 (S) and fluconazole-resistant (FR) strains were adjusted to the turbidity of a 0.5 McFarland standard. Each strain was allocated into 4 groups: S1 and FR1) control groups, S2 and FR2) ICG-treated groups (1 µg/mL), S3 and FR3) laser-irradiated groups (wavelength: 810 nm; mode: continuous-wave; output power: 300 mW; spot size: 4.5 mm; exposure time: 120 s; radiation dose: 228 J/cm2), S4 and FR4) ICG-mediated-aPDT groups. After treatments, the number of colony-forming units per milliliter (CFU/mL) was calculated. Using the XTT reduction assay, the effects of each treatment on Candida biofilm formation were evaluated. Data were analyzed using SPSS software version 22. In both strains, the maximum number of CFUs was observed in the control group, followed by ICG-treated, laser-irradiated, and ICG-mediated-aPDT groups. In ATCC 10,231 strain, the XTT assay exhibited significant difference between ICG-mediated-aPDT and control groups (p < 0.0001). However, the ICG, laser, and ICG-mediated-aPDT groups in fluconazole-resistant strain showed significant differences when compared with the control (p < 0.05). The mean Candida CFUs and the XTT assay did not show any significant difference between the ATCC 10,231 and fluconazole-resistant strains with respect to each treatment. Data suggest ICG-mediated-aPDT could diminish Candida CFUs in laboratory; however, further studies are warranted to confirm its efficacy and safety to be applied in clinics.