Mechanisms of azole resistance in clinical isolates of Candida glabrata from two hospitals in China

Molecular Evaluation of the mRNA Expression of the ERG11, ERG3, CgCDR1, and CgSNQ2 Genes Linked to Fluconazole Resistance in Candida glabrata in a Colombian Population

INTRODUCTION

The study of Candida glabrata genes associated with fluconazole resistance, from a molecular perspective, increases the understanding of the phenomenon with a view to its clinical applicability.

OBJECTIVE

We sought to establish the predictive molecular profile of fluconazole resistance in Candida glabrata by analyzing the ERG11, ERG3, CgCDR1, and CgSNQ2 genes.

METHOD

Expression was quantified using RT-qPCR. Metrics were obtained through molecular docking and Fisher discriminant functions. Additionally, a predictive classification was made against the susceptibility of C. glabrata to fluconazole.

RESULTS

The relative expression of the ERG3, CgCDR1, and CgSNQ2 genes was higher in the fluconazole-resistant strains than in the fluconazole-susceptible, dose-dependent strains. The gene with the highest relative expression in the fluconazole-exposed strains was CgCDR1, and in both the resistant and susceptible, dose-dependent strains exposed to fluconazole, this was also the case. The molecular docking model generated a median number of contacts between fluconazole and ERG11 that was lower than the median number of contacts between fluconazole and ERG3, -CgCDR1, and -CgSNQ2. The predicted classification through the multivariate model for fluconazole susceptibility achieved an accuracy of 73.5%.

CONCLUSION

The resistant strains had significant expression levels of genes encoding efflux pumps and the ERG3 gene. Molecular analysis makes the identification of a low affinity between fluconazole and its pharmacological target possible, which may explain the lower intrinsic susceptibility of the fungus to fluconazole.

Candida glabrata (Nakaseomyces glabrata): A systematic review of clinical and microbiological data from 2011 to 2021 to inform the World Health Organization Fungal Priority Pathogens List

Recognising the growing global burden of fungal infections, the World Health Organization (WHO) established an advisory group consisting of experts in fungal diseases to develop a Fungal Priority Pathogen List. Pathogens were ranked based on their research and development needs and perceived public health importance using a series of global surveys and pathogen characteristics derived from systematic reviews. This systematic review evaluates the features and global impact of invasive disease caused by Candida glabrata (Nakaseomyces glabrata). PubMed and Web of Science were searched for studies reporting on mortality, morbidity (hospitalization and disability), drug resistance (including isolates from sterile and non-sterile sites, since these reflect the same organisms causing invasive infections), preventability, yearly incidence, diagnostics, treatability, and distribution/emergence in the last 10 years. Candida glabrata (N. glabrata) causes difficult-to-treat invasive infections, particularly in patients with underlying conditions such as immunodeficiency, diabetes, or those who have received broad-spectrum antibiotics or chemotherapy. Beyond standard infection prevention and control measures, no specific preventative measures have been described. We found that infection is associated with high mortality rates and that there is a lack of data on complications and sequelae. Resistance to azoles is common and well described in echinocandins-in both cases, the resistance rates are increasing. Candida glabrata remains mostly susceptible to amphotericin and flucytosine. However, the incidence of the disease is increasing, both at the population level and as a proportion of all invasive yeast infections, and the increases appear related to the use of antifungal agents.

Synergistic and potential antifungal properties of tailored, one pot multicomponent monoterpenes co-delivered with fluconazole encapsulated nanostructure lipid carrier

Frequent and variant infections are caused by the virtue of opportunistic fungi pathogens. Candidiasis, aspergillosis, and mucormycosis are pathogenic microorganisms that give rise to vast fungal diseases that alternate between moderate to fatal in severity. The use of fluconazole as an antifungal drug was limited due to the acquired resistance in some types of Candida and other fungal species. This study aims to consolidate fluconazole's biological effectiveness against several pathogenic fungi. Six active monoterpenes (MTs) of carvacrol, linalool, geraniol, α-terpinene, citronellal, and nerolidol were selected and encapsulated in nanostructure lipid carrier (NLC) with (NLC-Flu-MTs) and/without (NLC-MTs) fluconazole in one nanoformulation to determine if they will act synergistically or not? The synthesized nanoformulation NLC-Flu-MTs and NLC-MTs exhibited very good particle size of 144.5 nm and 138.6 nm for size and zeta potential values of (- 23.5 mV) and (- 20.3 mV), respectively. Transmission electron microscope investigation confirmed that the synthesized NLCs have regular and spherical shape. The abundance and concentration of the six released monoterpenes were determined, as a novel approach, using GC-MS with very good results and validity. In-vitro antifungal screening was done before and after nano co-delivery against seven pathogenic, and aggressive fungi of Candida tropicalis, Candida krusei, Candida glabrata, Geotrichum Candidum, Candidaalbicans, Aspergillus Niger, and mucor circinelloides. Inhibition Zone diameter (IZD) and the minimum inhibitory concentration (MIC) were measured. Nanoformulations NLC-Flu-MTs and NLC-MTs manifested potential and unique biological susceptibility against all the tested microorganisms with reduced (MIC) values, especially against Candida Tropicalis (MIC = 0.97 µg/ml) which represents 16-fold of the value shown by NLC-MTs (MIC = 15.6 µg/ml) and 64-fold of fluconazole free before nanoformulation (MIC = 62.5 µg/ml). The efficiency of nanomaterials, particularly NLC-Flu-MTs, has become evident in the diminishing value of MIC which affirmed the synergism between fluconazole and the other six monoterpenes.

Molecular mechanisms of azole resistance in Candida glabrata isolated from oropharyngeal candidiasis in head and neck cancer patients

OBJECTIVE

The aim of the current work was to assess the molecular mechanisms of fluconazole-resistant Candida glabrata strains isolated from oropharyngeal candidiasis (OPC) in head and neck patients, as well as evaluation of virulence factors.

DESIGN

Antifungal susceptibility pattern of sixty six clinical isolates of C. glabrata were evaluated by broth-microdilution method. The expression of ERG11, CDR1, CDR2, PDR1 genes as well as ERG11 gene capable of possible mutations was also detected in 21 fluconazol-resistant C. glabrata isolates. Phospholipase and proteinase activity of these isolates was estimated, too. The correlation between the virulence factors, antifungal susceptibility patterns and cancer type was also analyzed.

RESULTS

Seven synonymous and four non-synonymous mutations were found in 21 fluconazole-resistant C. glabrata isolates; subsequently, four amino acid substitutions including H257P, Q47H, S487Y and I285N were then reported for the first time. High expression of CDR1 and PDR1 in related to other gene findings were tested in these isolates. Additionally, there was no significant difference between stage of cancer and MIC of all antimicrobial drugs. Significant differences between MIC of fluconazole, voriconazole and cancer types were also, found. The proteinase activity (92.4%) was higher than phospholipase activity in the isolates. Further, no significant difference between proteinase (rs: 0.003), phospholipase (rs: -0.107) activity and fluconazole MICs was observed.

CONCLUSION

C. glabrata isolated from OPC in head and neck patients represented high capacities for proteolytic enzymes activity and high mRNA level of CDR1 and PDR1 gene and ERG11 mutations play an important role in azole drug resistance.

Distribution and antifungal susceptibility pattern of Candida species from mainland China: A systematic analysis

Antifungal resistance to Candida pathogens increases morbidity and mortality of immunosuppressive patients, an emerging crisis worldwide. Understanding the Candida prevalence and antifungal susceptibility pattern is necessary to control and treat candidiasis. We aimed to systematically analyse the susceptibility profiles of Candida species published in the last ten years (December 2011 to December 2021) from mainland China. The studies were collected from PubMed, Google Scholar, and Science Direct search engines. Out of 89 included studies, a total of 44,716 Candida isolates were collected, mainly comprising C. albicans (49.36%), C. tropicalis (21.89%), C. parapsilosis (13.92%), and C. glabrata (11.37%). The lowest susceptibility was detected for azole group; fluconazole susceptibilities against C. parapsilosis, C. albicans, C. glabrata, C. tropicalis, C. guilliermondii, C. pelliculosa, and C. auris were 93.25%, 91.6%, 79.4%, 77.95%, 76%, 50%, and 0% respectively. Amphotericin B and anidulafungin were the most susceptible drugs for all Candida species. Resistance to azole was mainly linked with mutations in ERG11, ERG3, ERG4, MRR1-2, MSH-2, and PDR-1 genes. Mutation in FKS-1 and FKS-2 in C. auris and C. glabrata causing resistance to echinocandins was stated in two studies. Gaps in the studies' characteristics were detected, such as 79.77%, 47.19 %, 26.97%, 7.86%, and 4.49% studies did not mention the mortality rates, age, gender, breakpoint reference guidelines, and fungal identification method, respectively. The current study demonstrates the overall antifungal susceptibility pattern of Candida species, gaps in surveillance studies and risk-reduction strategies that could be supportive in candidiasis therapy and for the researchers in their future studies.

Comparison of the antifungal effect of voriconazole and fluconazole on oral candidiasis before and during radiotherapy

Background

Head-and-neck radiotherapy can change oral Candida species and cause candidiasis resistance to common antifungals by making the changes to the oral cavity environment. Voriconazole is a synthetic azole with extensive antifungal activity. The current study aimed at comparing the antifungal activity of fluconazole and voriconazole on Candida species isolated from the oral cavity of patients undergoing head-and-neck radiotherapy.

Materials and Methods

The present in vitro study was performed on samples isolated from patients undergoing head-and-neck radiotherapy, before and during radiotherapy. After the identification of the species, the antifungal effect of fluconazole and voriconazole was determined by the microdilution method, and the minimum inhibitory concentration (MIC), the minimum fungicidal concentration, and the antifungal susceptibility of the isolated strains were also measured. The data were analyzed by the Chi-squared and then two-sided Fisher's exact tests. P < 0.05 was considered statistically significant.

Results

The study findings showed no significant difference in the susceptibility of Candida albicans to voriconazole and fluconazole before and during radiotherapy. Before radiotherapy, both voriconazole and fluconazole had similar effects on Candida tropicalis, but after radiotherapy, voriconazole was less effective. However, both before and during radiotherapy, fluconazole had a greater antifungal effect than voriconazole on Candida glabrata strains. The MICs of voriconazole and fluconazole for both Candida parapsilosis and Candida krusei isolates were within the susceptible or dose-dependent range.

Conclusion

The current study results showed that voriconazole was not more effective than fluconazole in the treatment of oral candidiasis in patients undergoing head-and-neck radiotherapy.

A New Variant of Mutational and Polymorphic Signatures in the ERG11 Gene of Fluconazole-Resistant Candida albicans

Background

Resistance to antifungal drugs for treating Candida infections remains a major concern globally despite the range of medications available. Most of these drugs target key proteins essential to the life cycle of the organism. An enzyme essential for fungal cell membrane integrity, lanosterol 14–α demethylase (CYP51), is encoded by the ERG11 gene in Candida species. This enzyme is the target of azole–based drugs. The organism has, however, devised molecular adaptations to evade the activity of these drugs.

Materials and Methods

Classical methods were employed to characterize clinical isolates sampled from women and dogs of reproductive age. For fluconazole efficacy studies, CLSI guidelines on drug susceptibility testing were used. To understand the susceptibility pattern, various molecular and structural analytic approaches, including sequencing, in silico site-directed mutagenesis, and protein-ligand profiling, were applied to the ERG11 gene and CYP51 protein sequences. Several platforms, comprising Clustal Omega, Pymol plugin manager, Pymol molecular visualizer, Chimera–curated Dynameomics rotamer library, protein–ligand interaction profiler, Charmm36 force field, GROMACS, Geneious, and Mega7, were employed for this analysis.

Results

The following Candida species distribution was obtained: 37.84% C. albicans, 8.12% C. glabrata, 10.81% C. krusei, 5.41% C. tropicalis, and 37.84% of other unidentified Candida species. Two codons in the nucleotide sequence of the wild-type (CTC and CCA) coding for LEU–370 and PRO–375, respectively, were mutated to L370S and P375H in the resistant strain. The mutation stabilized the protein at the expense of the heme moiety. We found that the susceptible isolate from dogs (Can–iso–029/dog) is closely related to the most resistant isolate from humans.

Conclusion

Taken together, our results showed new mutations in the heme-binding pocket of caCYP51 that explain the resistance to fluconazole exhibited by the Candida isolates. So far, the L370S and P375H resistance-linked mutations have not been previously reported.

Multilocus Sequence Typing and Antifungal Susceptibility of Vaginal and Non-vaginal Candida glabrata Isolates From China

Candida glabrata is a common cause of Candida infections. In our present study, we investigated the antifungal susceptibility and molecular epidemiology of vaginal and non-vaginal C. glabrata isolates. Seventy-six vaginal C. glabrata strains isolated from patients with vulvovaginal candidiasis and 57 non-vaginal C. glabrata isolates were collected at two hospitals in Shanghai, China. Antifungal susceptibility was examined using a broth microdilution method. Multilocus sequence typing was used for genotyping. Overall, 28 (21.1%), 28 (21.1%), and 29 (21.8%) C. glabrata isolates were resistant to fluconazole, itraconazole, and voriconazole, respectively. Briefly, 18 (23.7%), 18 (23.7%), and 19 (25%) vaginal strains were resistant to fluconazole, itraconazole, and voriconazole. While the resistance to these antifungals were all 17.5% (10/57) in non-vaginal strains. All isolates retained susceptibility to amphotericin B, and only four non-vaginal isolates were caspofungin resistant. Genotyping identified 17 ST patterns. In non-vaginal samples, the same genotypes appear as in the vaginal samples, except for one genotype (ST-182), while in the vaginal samples more genotypes appear (ST8, ST19, ST45, ST55, ST66, ST80, ST138, and ST17). The most common genotype was ST7 (81 strains), followed by ST10 (14 strains) and ST15 (11 strains). The majority of resistant phenotype strains (25/30, 83.3%) correlated to the predominant genotype (ST7), and the rest belonged to ST3 (2/30, 6.7%), ST10 (1/30, 3.3%), ST19 (1/30, 3.3%), and ST45 (1/30, 3.3%). Our survey revealed cross-resistance in vaginal and non-vaginal C. glabrata isolates. Moreover, there is no genotype associated with the resistance phenotype.

Antifungal susceptibility profile of invasive Candida glabrata isolates (2009-2020) from a tertiary care hospital laboratory in Pakistan

Introduction. Invasive infections with Candida glabrata are a global concern due to poor clinical outcomes and propensity to acquire resistance to antifungal agents. Hypothesis/Gap Statement. Monitoring emerging resistance and trends in Candida glabrata, an important agent of candidemia in Pakistan, is critical for patient management; data that is missing from Pakistan. Aim. Thus, this study evaluated antifungal resistance and MICs) distribution in invasive C. glabrata isolates from Pakistan. Methods. This cross-sectional and retrospective study was conducted from January 2009 to March 2020 at a clinical laboratory in Pakistan that has a nation-wide network. Antifungal susceptibility data of 277 candidemia, deep organ and soft tissue (invasive) C. glabrata sensu lato isolates against fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, micafungin, caspofungin and amphotericin B was retrieved. Susceptibility testing was performed using colorimetric broth microdilution and interpreted using CLSI criteria. Demographics, clinical history and outcome were studied. Chi-square test was used to demonstrate association between antifungal resistance and clinical characteristics of the patients. Results. We identified 277 patients with invasive C. glabrata infection. Of which 48 (18.4%) isolates were resistant to fluconazole (MIC ≥64 mg l^-1), one isolate each was resistant to amphotericin (MIC=2 mg l^-1), anidulafungin (MIC=1 mg l^-1) and micafungin (MIC=0.5 mg l^-1). MIC₉₀ for fluconazole was 64 mg l^-1 and other triazoles 2 mg l^-1, caspofungin 0.12 mg l^-1, anidulafungin 0.06 mg l^-1, micafungin 0.03 mg l^-1 and amphotericin 0.5 mg l^-1. Fluconazole MIC ≥64 mg l^-1, caspofungin MIC >0.06 mg l^-1 and amphotericin MIC >0.25 mg l^-1 (above MIC₅₀) were significantly associated with patient being alive at the time of reporting, no use of healthcare devices, nor infection with other fungi. Fluconazole resistance was significantly associated with prior antifungal use by the patient. Conclusion. Surveillance data of antifungal resistance among common Candida species should be monitored closely for identification of resistant strains.

Danish Whole-Genome-Sequenced Candida albicans and Candida glabrata Samples Fit into Globally Prevalent Clades

Candida albicans and Candida glabrata are opportunistic fungal pathogens with increasing incidence worldwide and higher-than-expected prevalence in Denmark. We whole-genome sequenced yeast isolates collected from Danish Clinical Microbiology Laboratories to obtain an overview of the Candida population in the country. The majority of the 30 C. albicans isolates were found to belong to three globally prevalent clades, and, with one exception, the remaining isolates were also predicted to cluster with samples from other geographical locations. Similarly, most of the eight C. glabrata isolates were predicted to be prevalent subtypes. Antifungal susceptibility testing proved all C. albicans isolates to be susceptible to both azoles and echinocandins. Two C. glabrata isolates presented azole-resistant phenotypes, yet all were susceptible to echinocandins. There is no indication of causality between population structure and resistance phenotypes for either species.

Antisense locked nucleic acid gapmers to control Candida albicans filamentation

Whereas locked nucleic acid (LNA) has been extensively used to control gene expression, it has never been exploited to control Candida virulence genes. Thus, the main goal of this work was to compare the efficacy of five different LNA-based antisense oligonucleotides (ASO) with respect to the ability to control EFG1 gene expression, to modulate filamentation and to reduce C. albicans virulence. In vitro, all LNA-ASOs were able to significantly reduce C. albicans filamentation and to control EFG1 gene expression. Using the in vivo Galleria mellonella model, important differences among the five LNA-ASOs were revealed in terms of C. albicans virulence reduction. The inclusion of PS-linkage and palmitoyl-2'-amino-LNA chemical modification in these five LNA gapmers proved to be the most promising combination, increasing the survival of G. mellonella by 40%. Our work confirms that LNA-ASOs are useful tools for research and therapeutic development in the candidiasis field.

Role of Antifungal Combinations in Difficult to Treat Candida Infections

Candida infections are varied and, depending on the immune status of the patient, a life-threatening form may develop. C. albicans is the most prevalent species isolated, however, a significant shift towards other Candida species has been noted. Monotherapy is frequently indicated, but the patient's evolution is not always favorable. Drug combinations are a suitable option in specific situations. The aim of this review is to address this problem and to discuss the role of drug combinations in difficult to treat Candida infections. A search for eligible studies in PubMed and Google Scholar databases was performed. An analysis of the data was carried out to define in which cases a combination therapy is the most appropriate. Combination therapy may be used for refractory candidiasis, endocarditis, meningitis, eye infections and osteomyelitis, among others. The role of the drug combination would be to increase efficacy, reduce toxicity and improve the prognosis of the patient in infections that are difficult to treat. More clinical studies and reporting of cases in which drug combinations are used are needed in order to have more data that support the use of this therapeutic strategy.

Antimycotic Drugs and their Mechanisms of Resistance to Candida Species

Fungal infections have shown an upsurge in recent decades, which is mainly because of the increasing number of immunocompromised patients and the occurrence of invasive candidiasis has been found to be 7-15 fold greater than that of invasive aspergillosis. The genus Candida comprises more than 150 distinct species, however, only a few of them are found to be pathogenic to humans. Mortality rates of Candida species are found to be around 45% and the reasons for this intensified mortality are inefficient diagnostic techniques and unfitting initial treatment strategies. There are only a few antifungal drug classes that are employed for the remedy of invasive fungal infections. which include azoles, polyenes, echinocandins, and pyrimidine analogs. During the last 2-3 decades, the usage of antifungal drugs has increased several folds due to which the reports of escalating antifungal drug resistance have also been recorded. The resistance is mostly to the triazole- based compounds. Due to the occurrence of antifungal drug resistance, the success rates of treatment have been reduced as well as major changes have been observed in the frequency of fungal infections. In this review, we have summarized the major molecular mechanisms for the development of antifungal drug resistance.

Invasive para-aortic Candida glabrata: a multidisciplinary management challenge

A 69-year-old man was admitted with recurrent fungal bloodstream infection on a background of abdominal aneurysm, diabetes and chronic obstructive pulmonary disease. Investigations revealed a para-aortic mass, previously thought to be lymphoma, which was culture positive for Candida glabrata on biopsy. Diagnosis and management involved multidisciplinary teamwork, diagnostic uncertainty and significant risk taking.

Pyrogallol and Fluconazole Interact Synergistically In Vitro against Candida glabrata through an Efflux-Associated Mechanism

Candida glabrata is currently the first or second most commonly encountered non-albicans Candida species worldwide. The potential severity of Candida resistance mandates the discovery of novel antifungal agents, including those that can be used in combination therapies. In this study, we evaluated the in vitro interactions of pyrogallol (PG) and azole drugs against 22 clinical C. glabrata isolates. The potential mechanism underlying the synergism between PG and fluconazole (FLC) was investigated by the rhodamine 6G efflux method and quantitative reverse transcription (qRT)-PCR analysis. In susceptibility tests, PG showed strong synergism with FLC, itraconazole (ITC), and voriconazole (VRC), with fractional inhibitory concentration index values of 0.18 to 0.375 for PG+FLC, 0.250 to 0.750 for PG+ITC, and 0.141 to 0.750 for PG+VRC. Cells grown in the presence of PG+FLC exhibited reduced rhodamine 6G extrusion and significantly downregulated expression of the efflux-related genes CgCDR1, CgCDR2, and CgPDR1 compared with cells grown in the presence of PG or FLC alone. PG did not potentiate FLC when tested against a ΔCgpdr1 strain. Restoration of a functional CgPDR1 allele also restored the synergism. These results indicate that PG is an antifungal agent that synergistically potentiates the activity of azoles. Furthermore, PG appears to exert its effects by inhibiting efflux pumps and downregulating CgCDR1, CgCDR2, and CgPDR1, with CgPDR1 probably playing a crucial role in this process.

A Review on Molecular Mechanisms of Antifungal Resistance in Candida glabrata: Update and Recent Advances

Candida glabrata is the second frequent etiologic agent of mucosal and invasive candidiasis. Based on the recent developments in molecular methods, C. glabrata has been introduced as a complex composed of C. glabrata, Candida nivariensis, and Candida bracarensis. The four main classes of antifungal drugs effective against C. glabrata are pyrimidine analogs (flucytosine), azoles, echinocandins, and polyenes. Although the use of antifungal drugs is related to the predictable development of drug resistance, it is not clear why C. glabrata is able to rapidly resist against multiple antifungals in clinics. The enhanced incidence and antifungal resistance of C. glabrata and the high mortality and morbidity need more investigation regarding the resistance mechanisms and virulence associated with C. glabrata; additional progress concerning the drug resistance of C. glabrata has to be further prevented. The present review highlights the mechanism of resistance to antifungal drugs in C. glabrata.

Drug-Resistant Fungi: An Emerging Challenge Threatening Our Limited Antifungal Armamentarium

The high clinical mortality and economic burden posed by invasive fungal infections (IFIs), along with significant agricultural crop loss caused by various fungal species, has resulted in the widespread use of antifungal agents. Selective drug pressure, fungal attributes, and host- and drug-related factors have counteracted the efficacy of the limited systemic antifungal drugs and changed the epidemiological landscape of IFIs. Species belonging to Candida, Aspergillus, Cryptococcus, and Pneumocystis are among the fungal pathogens showing notable rates of antifungal resistance. Drug-resistant fungi from the environment are increasingly identified in clinical settings. Furthermore, we have a limited understanding of drug class-specific resistance mechanisms in emerging Candida species. The establishment of antifungal stewardship programs in both clinical and agricultural fields and the inclusion of species identification, antifungal susceptibility testing, and therapeutic drug monitoring practices in the clinic can minimize the emergence of drug-resistant fungi. New antifungal drugs featuring promising therapeutic profiles have great promise to treat drug-resistant fungi in the clinical setting. Mitigating antifungal tolerance, a prelude to the emergence of resistance, also requires the development of effective and fungal-specific adjuvants to be used in combination with systemic antifungals.

Oral Ibrexafungerp: an investigational agent for the treatment of vulvovaginal candidiasis

INTRODUCTION

Vulvovaginal candidiasis (VVC) is a common fungal infection caused by predominantly Candida albicans, and is diagnosed in up to 40% of women with vaginal complaints in the primary care setting. Approximately 75% of women experience at least one episode during their reproductive years.

AREAS COVERED

Ibrexafungerp is an orally active, semi-synthetic triterpenoid glucan synthase inhibitor under development for treatment and prevention of VVC. We present the chemistry, mechanism of action, pharmacology, microbiology, and results from clinical studies with ibrexafungerp in women with VVC.

EXPERT OPINION

Ibrexafungerp addresses several unmet needs with existing antifungal drugs as a first in a new class of antifungal agents with a novel mechanism of action demonstrating no antifungal cross resistance with azoles, and fungicidal activity against Candida spp., including fluconazole-resistant species. Some of the key attributes of ibrexafungerp related to VVC include oral one-day dosing, high tissue penetration, enhanced activity at low pH seen in the vagina, low risk for clinically significant drug-drug interactions, and a low risk of adverse events. If approved, ibrexafungerp will be the first new antifungal agent available for the treatment of VVC in more than 20 years and the only oral, non-azole antifungal approved for women suffering from VVC.

Antifungal Activity of ZnO Nanoparticles and Nystatin and Downregulation of SAP1-3 Genes Expression in Fluconazole-Resistant Candida albicans Isolates from Vulvovaginal Candidiasis

Purpose

Antifungal resistance and virulence properties of Candida albicans (C. albicans) are growing health problems worldwide. The present study aims to investigate the effect of Zinc Oxide (ZnO) nanoparticles and Nystatin on SAP1-3 genes expression in C. albicans isolates of females with Vulvovaginal Candidiasis (VVC) isolated from Sayad Shirazi Obstetrics and Gynecology Hospital in Northeastern Iran during 2017–2018.

Patients and Methods

In this descriptive-analytic study, vaginal samples were collected from 280 VVC women. 196 (70%) of C. albicans isolates were identified by phenotypic and ITS genotypic methods. Susceptibility to Fluconazole C. albicans isolates was determined by the disk diffusion method. Detection of ERG11 gene was done by RT-PCR technique.

Results

It was revealed that PCR amplified the ERG11 gene in all of the Fluconazole-resistant isolates. Real-time PCR was used to survey the effects of 3±1.7µg/mL concentrations of ZnO nanoparticles and Nystatin on expression of SAP1-3 genes before and after treatment. 186 (95%) susceptible C. albicans and 10 (5%) Fluconazole-resistant C. albicans isolates from VVC were exposed to sub-minimum inhibitory concentrations (Sub-MIC) of ZnO-np (range=0.02–12 μg/mL). Sub-MIC concentration was used for each strain, which reduced the expression of SAP1-3 genes to 1.8 MIC in the vaginal swabs. The observed reduction in gene expression was significant for both ZnO nanoparticles and Nystatin (P=0.01 and P=0.07, respectively).

Conclusion

ZnO as antifungal agent can well reduce the growth and gene expression of SAP1-3 in the pathogenesis of VVC.