In Vitro Antifungal Activity of Ibrexafungerp (SCY-078) Against Contemporary Blood Isolates From Medically Relevant Species of Candida: A European Study.

Background: Ibrexafungerp (SCY-078) is the newest oral and intravenous antifungal drug with broad activity, currently undergoing clinical trials for invasive candidiasis. Objective: The aim of this study was to assess the in vitro activity of ibrexafungerp and comparators against a collection of 434 European blood isolates of Candida. Methods: Ibrexafungerp, caspofungin, fluconazole, and micafungin minimum inhibitory concentrations (MICs) were collected from 12 European laboratories for 434 blood isolates, including 163 Candida albicans, 108 Candida parapsilosis, 60 Candida glabrata, 40 Candida tropicalis, 29 Candida krusei, 20 Candida orthopsilosis, 6 Candida guilliermondii, 2 Candida famata, 2 Candida lusitaniae, and 1 isolate each of Candida bracarensis, Candida catenulata, Candida dubliniensis, and Candida kefyr. MICs were determined by the EUCAST broth microdilution method, and isolates were classified according to recommended clinical breakpoints and epidemiological cutoffs. Additionally, 22 Candida auris from different clinical specimens were evaluated. Results: Ibrexafungerp MICs ranged from 0.016 to ≥8 mg/L. The lowest ibrexafungerp MICs were observed for C. albicans (geometric MIC 0.062 mg/L, MIC range 0.016-0.5 mg/L) and the highest ibrexafungerp MICs were observed for C. tropicalis (geometric MIC 0.517 mg/L, MIC range 0.06-≥8 mg/L). Modal MICs/MIC50s (mg/L) against Candida spp. were 0.125/0.06 for C. albicans, 0.5/0.5 for C. parapsilosis, 0.25/0.25 for C. glabrata, 0.5/0.5 for C. tropicalis, 1/1 for C. krusei, 4/2 for C. orthopsilosis, and 0.5/0.5 for C. auris. Ibrexafungerp showed activity against fluconazole- and echinocandin-resistant isolates. If adopting wild-type upper limits, a non-wild-type phenotype for ibrexafungerp was only observed for 16/434 (3.7%) isolates: 11 (4.6%) C. parapsilosis, 4 (5%) C. glabrata, and 1 (2.5%) C. tropicalis. Conclusion: Ibrexafungerp showed a potent in vitro activity against Candida.

In vitro and in vivo anti-Candida activity of citral in combination with fluconazole.

BACKGROUND: The ability of Candida to develop biofilms on inert surfaces or living tissues favors recalcitrant and chronic candidiasis associated, in many instances, with resistance to current antifungal therapy. AIM: The aim of this study was to evaluate the antifungal activity of citral, a phytocompound present in lemongrass essential oil, in monotherapy and combined with fluconazole against azole-resistant Candida planktonic cells and biofilms. The effect of citral combined with fluconazole was also analysed with regard to the expression of fluconazole resistance-associated genes in Candida albicans and the effectiveness of the combination therapy in a Caenorhabditis elegans model of candidiasis. RESULTS: Citral reduced biofilm formation at initial stages and the metabolic activity of the mature biofilm. The combination of citral with fluconazole was synergistic, with a significant increase in the survival of C. elegans infected with Candida. RNA analysis revealed a reduction of the expression of the efflux pump encoded by MDR1, leading to a greater effect of fluconazole. CONCLUSION: Citral in monotherapy and in combination with fluconazole could represent an interesting therapy to treat recalcitrant Candida infections associated to biofilms.

In vitro activities of carvacrol, cinnamaldehyde and thymol against Candida biofilms.

Oral candidiasis is frequently associated with Candida biofilms. Biofilms are microbial communities related to persistent, recalcitrant and difficult to-treat infections. Conventional treatments are not sufficient to overcome biofilm-associated candidiasis; thus, the search of new antifungal compounds is necessary. In the current study, we have evaluated the effect of three phytocompounds, carvacrol, cinnamaldehyde and thymol, against Candida planktonic and sessile cells. Reduction in biofilm biomass and metabolic activity was assessed during adhesion and mature biofilm phases. Candida albicans was the most biofilm-producing Candida species. All phytocompounds tested were fungicidal against Candida planktonic cells. Cinnamaldehyde was the most active in inhibiting biofilm adhesion, but carvacrol and thymol significantly reduced both mature biofilm biomass and metabolic activity. These results highlight the role of cinnamaldehyde, carvacrol and thymol as promising alternatives for the treatment of candidiasis due to their antibiofilm capacities, and stress the necessity to continue studies on their safety, toxicity and pharmacodynamics and pharmacokinetics.

Development and Characterization of Monoolein-Based Liposomes of Carvacrol, Cinnamaldehyde, Citral, or Thymol with Anti-Candida Activities.

There is an increasing need for novel drugs and new strategies for the therapy of invasive candidiasis. This study aimed to develop and characterize liposome-based nanoparticles of carvacrol, cinnamaldehyde, citral, and thymol with anti-Candida activities. Dioctadecyldimethylammonium bromide- and monoolein-based liposomes in a 1:2 molar ratio were prepared using a lipid-film hydration method. Liposomes were assembled with equal volumes of liposomal stock dispersion and stock solutions of carvacrol, cinnamaldehyde, citral, or thymol in dimethyl sulfoxide. Cytotoxicity was tested on RAW 264.7 macrophages. In vitro antifungal activity of liposomes with phytocompounds was evaluated according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) methodology using clinical isolates of Candida albicans, Candida auris, Candida dubliniensis, and Candida tropicalis Finally, the ability of macrophage cells to kill Candida isolates after addition of phytocompounds and their nanoparticles was determined. Nanoparticles with 64 µg/ml of cinnamaldehyde, 256 µg/ml of citral, and 128 µg/ml of thymol had the best characteristics among the formulations tested. The highest encapsulation efficiencies were achieved with citral (78% to 83%) and carvacrol (66% to 71%) liposomes. Carvacrol and thymol in liposome-based nanoparticles were nontoxic regardless of the concentration. Moreover, carvacrol and thymol maintained their antifungal activity after encapsulation, and there was a significant reduction (∼41%) of yeast survival when macrophages were incubated with carvacrol or thymol liposomes. In conclusion, carvacrol and thymol liposomes possess high stability, low cytotoxicity, and antifungal activity that act synergistically with macrophages.

Candida duobushaemulonii: An Old But Unreported Pathogen.

Candidiasis caused by species of the Candida haemulonii complex (Candida haemulonii and Candida duobushaemulonii) and closely related species, Candida auris and Candida pseudohaemulonii are increasing. These species often show reduced susceptibility to antifungal drugs, such as azoles and amphotericin B or, less frequently, echinocandins. However, conventional phenotypic identification methods are unable to accurately differentiate these species and, therefore, their prevalence may have been underestimated. In this study, 150 isolates that were probably misidentified were reanalyzed using two novel PCR approaches. We found that one isolate previously identified in 1996 as Candida intermedia was C. duobushaemulonii, being one of the oldest isolates of this species described to date. We also found that this isolate had reduced susceptibility to fluconazole, itraconazole, and amphotericin B.

Utility of two PCR-RFLP-based techniques for identification of Candida parapsilosis complex blood isolates.

BACKGROUND: Candida parapsilosis is the second or third most frequently isolated Candida species related to nosocomial infections, even overtaking Candida albicans in some hospitals. C. parapsilosis constitutes a complex of closely related species: Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. Accurate detection of these species is of importance, as the incidence of C. orthopsilosis has been reported to surpass that of Candida krusei. OBJECTIVE: To evaluate the diagnostic utility of two PCR-RFLP methods targeting the SADH and FKS1 genes and to determine the prevalence of cryptic species in 96 bloodstream isolates of C. parapsilosis from 93 patients. METHODS: Restriction patterns of the SADH and FKS1 genes were analysed, and sequencing of the D1/D2 regions of the ribosomal RNA was used to evaluate the reliability of both PCR-RFLP methods. RESULTS: In our study, 77 C. parapsilosis sensu stricto, 13 C. orthopsilosis and five C. metapsilosis were identified by sequencing. Both PCR-RFLP methods demonstrated strong agreement with D1/D2 sequencing in the identification of C. parapsilosis and C. orthopsilosis, while both methods were unable to identify the C. metapsilosis isolates. Moreover, unexpected restriction patterns were observed for two isolates on SADH PCR-RFLP and for four isolates on FKS1 PCR-RFLP. Mixed bloodstream infections of C. parapsilosis sensu stricto and C. orthopsilosis were detected for three patients, for which differential growth characteristics were observed. CONCLUSION: The molecular method chosen for identification could have an impact on determination of the real prevalence of C. metapsilosis in candidaemia, and mixed fungaemias can remain undetected.

Corrigendum: Antifungal Activity of the Human Uterine Cervical Stem Cells Conditioned Medium (hUCESC-CM) Against Candida albicans and Other Medically Relevant Species of Candida.

[This corrects the article DOI: 10.3389/fmicb.2018.02818.].

Therapeutic tools for oral candidiasis: Current and new antifungal drugs

Background: Candidiasis is one of the most common opportunistic oral infections that presents different acute and chronic clinical presentations with diverse diagnostic and therapeutic approaches. The present study carries out a bibliographic review on the therapeutic tools available against oral candidiasis and their usefulness in each clinical situation. Material and Methods: Recent studies on treatment of oral candidiasis were retrieved from PubMed and Cochrane Library. Results: Nystatin and miconazole are the most commonly used topical antifungal drugs. Both antifungal drugs are very effective but need a long time of use to eradicate the infection. The pharmacological presentations of miconazole are more comfortable for patients but this drug may interact with other drugs and this fact should be assessed before use. Other topical alternatives for oral candidiasis, such as amphotericin B or clotrimazole, are not available in many countries. Oral fluconazole is effective in treating oral candidiasis that does not respond to topical treatment. Other systemic treatment alternatives, oral or intravenous, less used are itraconazole, voriconazole or posaconazole. Available novelties include echinocandins (anidulafungin, caspofungin) and isavuconazole. Echinocandins can only be used intravenously. Isavuconazole is available for oral and intravenous use. Other hopeful alternatives are new drugs, such as ibrexafungerp, or the use of antibodies, cytokines and antimicrobial peptides. Conclusions: Nystatin, miconazole, and fluconazole are very effective for treating oral candidiasis. There are systemic alternatives for treating recalcitrant infections, such as the new triazoles, echinocandins, or lipidic presentations of amphotericin B

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Antifungal Activity of the Human Uterine Cervical Stem Cells Conditioned Medium (hUCESC-CM) Against Candida albicans and Other Medically Relevant Species of Candida.

Background: Candidiasis is a major cause of human morbidity and mortality. Human uterine cervical stem cells conditioned medium (hUCESC-CM) is obtained from stromal stem cells of the cervical transformation zone, which are in permanent contact with a wide array of potential vaginal pathogens. In previous reports we have found that hUCESC-CM has antitumor and antibacterial potential. Since Candida is the most prevalent yeast in the human vagina, it seems plausible that hUCESC-CM might also show activity against it. Methods: In a preliminary step, to evaluate if hUCESC-CM showed any activity at all on Candida growth, in vitro activities of hUCESC-CM against fluconazole-susceptible reference strains of Candida albicans, Candida glabrata, Candida krusei, and Candida parapsilosis were studied with a microdilution method on RPMI 1640, using the BioScreen C microbiological incubator. Each measurement was repeated five times. The same methodology was used subsequently on fluconazole-susceptible and fluconazole-resistant Candida isolates from blood and vagina of those species corresponding to the reference strains of Candida against which activity had been detected in the previous study. Moreover, two fluconazole-resistant clinical isolates of Candida auris from blood and urine were also included. Findings: In vitro inhibitory activity of hUCESC-CM ranged from 57.5 to 96.6% growth-reduction against fluconazole-susceptible reference strains of Candida albicans, Candida glabrata, and Candida parapsilosis. hUCESC-CM also reduced the growth of all fluconazole-susceptible tested vaginal isolates by more than 50%. For fluconazole-resistant isolates, growth-reduction was higher than 67% for Candida albicans, regardless of its origin (vagina or blood). The isolate of Candida auris from urine with a MIC > 128 µ/ml for fluconazole was also significantly inhibited. However, hUCESC-CM was almost inactive against any of the fluconazole-resistant blood isolates of Candida glabrata, Candida parapsilosis, and Candida auris tested. Interpretation: This is the first report about the growth-inhibiting properties of conditioned medium from human stromal stem cells against different species of Candida. Antifungal activity of stromal stem cells depends on their site of origin, being most effective against Candida species most prevalent at that particular location. If confirmed in further studies, these findings might result in a completely new therapeutic approach against superficial and invasive candidiasis.

Oral Candida colonization in patients with chronic periodontitis. Is there any relationship? / Colonización oral por Candida en pacientes con enfermedad periodontal crónica. ¿Existe alguna relación?

Background: Candida can be implicated in the pathology of chronic periodontitis. Aims: To analyze the oral Candida carriage in patients suffering from chronic periodontitis (CP) and its correlation with the severity of this condition. Methods: Microbiological samples were taken from 155 patients using the oral rinse (OR) technique and by using paper points in the periodontal pockets (GPP). These patients were divided into 3 groups: 89 patients without CP (control), 47 with moderate CP, and 19 with severe CP. Samples were cultured in a Candida chromogenic agar for Candida. Species were identified by microbiological and molecular methods. Results: Candida was isolated in the OR of 45 (50.6%), 21 (44.7%), and 11 (57.9%) patients, respectively, and in the GPP of 32 (36%), 14 (29.2%), and 10 (42.6%) patients from the control, moderate CP and severe CP groups, respectively. Candida was isolated more frequently and in a greater burden in OR than in GPP (p<0.01). Candida albicans was the most prevalent species. GPP of patients with CP had poor fungal biodiversity (p<0.01). Conclusions: Colonization by Candida was present in the samples of patients without CP, and with both moderate and severe CP. Nonetheless, patients with severe CP had a higher rate of Candida colonization, especially by C. albicans

Antecedentes: Candida puede estar implicada en la patogenia de la enfermedad periodontal crónica. Objetivos: Analizar la colonización oral por Candida en pacientes con enfermedad periodontal (EP) crónica y su asociación con la gravedad de esta entidad clínica. Métodos: Se tomaron muestras microbiológicas de 155 pacientes mediante enjuagues orales e introduciendo una punta de papel estéril en la bolsa periodontal. Se dividieron los pacientes en tres grupos: 89 pacientes sin EP (control), 47 con EP moderada y 19 con EP grave. Las muestras se cultivaron en un agar cromógeno para Candida y las especies se identificaron mediante métodos microbiológicos tradicionales y moleculares. Resultados: Se aisló Candida en los enjuagues de 45 (50,6%), 21 (44,7%) y 11 (57,9%) pacientes y en las puntas de papel de 32 (36%), 14 (29,2%) y 10 (42,6%) pacientes de los grupos control, con EP moderada y con EP grave, respectivamente. Candida se aisló con mayor frecuencia y mayor carga fúngica en las muestras de los enjuagues que en las de las puntas de papel (p < 0,01). Candida albicans fue la especie más prevalente. Las muestras de la bolsa periodontal de los pacientes con EP presentaron una baja biodiversidad fúngica (p??0,01). Conclusiones: Hubo colonización por Candida en las muestras de pacientes sin EP y con EP tanto moderada como leve. No obstante, los pacientes con EP grave presentaron una mayor colonización por Candida, especialmente por C. albicans

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

OBJECTIVE: To evaluate the importance of Candida glabrata, Candida parapsilosis and their close-related species, Candida bracarensis, Candida nivariensis, Candida metapsilosis and Candida orthopsilosis in patients with oral candidiasis and, to determine the in vitro activities of antifungal drugs currently used for the treatment. METHODS: One hundred fourteen isolates of C. glabrata and 97 of C. parapsilosis, previously identified by conventional mycological methods, were analysed by molecular techniques. In vitro antifungal susceptibility to fluconazole, itraconazole, miconazole, and nystatin was evaluated by CLSI M44-A2 disk diffusion test, and by CLSI M27-A3 microdilution for fluconazole. RESULTS: All C. glabrata isolates were identified as C. glabrata sensu stricto, 93 out of 97 C. parapsilosis isolates as C. parapsilosis sensu stricto, three as C. orthopsilosis and one as C. metapsilosis. Candida glabrata was mainly isolated in mixed cultures but C. parapsilosis complex was more frequent in pure culture. Candida metapsilosis and C. orthopsilosis were isolated as pure culture and both species were susceptible to all antifungal agents tested. Most C. glabrata isolates were susceptible to miconazole and nystatin, but resistant to fluconazole and itraconazole. Azole cross resistance was also observed. Candida parapsilosis isolates were susceptible to fluconazole although azole cross resistance to miconazole and itraconazole was observed. CONCLUSION: This study highlights the importance of accurate identification and antifungal susceptibility testing of oral Candida isolates in order to have an in-depth understanding of the role of C. glabrata and C. parapsilosis in oral candidiasis.

Oral Candida colonization in patients with chronic periodontitis. Is there any relationship?

BACKGROUND: Candida can be implicated in the pathology of chronic periodontitis. AIMS: To analyze the oral Candida carriage in patients suffering from chronic periodontitis (CP) and its correlation with the severity of this condition. METHODS: Microbiological samples were taken from 155 patients using the oral rinse (OR) technique and by using paper points in the periodontal pockets (GPP). These patients were divided into 3 groups: 89 patients without CP (control), 47 with moderate CP, and 19 with severe CP. Samples were cultured in a Candida chromogenic agar for Candida. Species were identified by microbiological and molecular methods. RESULTS: Candida was isolated in the OR of 45 (50.6%), 21 (44.7%), and 11 (57.9%) patients, respectively, and in the GPP of 32 (36%), 14 (29.2%), and 10 (42.6%) patients from the control, moderate CP and severe CP groups, respectively. Candida was isolated more frequently and in a greater burden in OR than in GPP (p<0.01). Candida albicans was the most prevalent species. GPP of patients with CP had poor fungal biodiversity (p<0.01). CONCLUSIONS: Colonization by Candida was present in the samples of patients without CP, and with both moderate and severe CP. Nonetheless, patients with severe CP had a higher rate of Candida colonization, especially by C. albicans.

The continuous changes in the aetiology and epidemiology of invasive candidiasis: from familiar Candida albicans to multiresistant Candida auris.

Recent changes in the aetiology and epidemiology of invasive candidiasis have serious implications for current and future diagnosis, treatment and prognosis. The aim of the current review was to discuss the epidemiology of invasive candidiasis, the distribution of Candida species in different regions of the world, the medical concerns of the changing aetiology and the emergence of antifungal resistance. Overall burden of invasive candidiasis remains high, especially in vulnerable persons, such as the elderly, immunosuppressed or debilitated patients. Moreover, there is a progressive shift in the aetiology of invasive candidiasis from Candida albicans to other species of Candida, probably related to the increased use of azole drugs with a clear trend towards increased antifungal resistance. Finally, the emergence and rise of multiresistant species, such as Candida auris or Candida glabrata, is a major threat making necessary invasive candidiasis worldwide surveillances. These changes have serious implications for the diagnosis, treatment and prognosis of invasive candidiasis. Updated knowledge of the current local epidemiology of invasive candidiasis is critical for the clinical management.

Usefulness of the Non-conventional Caenorhabditis elegans Model to Assess Candida Virulence.

Invasive candidiasis is caused mainly by Candida albicans, but other Candida species have increasing etiologies. These species show different virulence and susceptibility levels to antifungal drugs. The aims of this study were to evaluate the usefulness of the non-conventional model Caenorhabditis elegans to assess the in vivo virulence of seven different Candida species and to compare the virulence in vivo with the in vitro production of proteinases and phospholipases, hemolytic activity and biofilm development capacity. One culture collection strain of each of seven Candida species (C. albicans, Candida dubliniensis, Candida glabrata, Candida krusei, Candida metapsilosis, Candida orthopsilosis and Candida parapsilosis) was studied. A double mutant C. elegans AU37 strain (glp-4;sek-1) was infected with Candida by ingestion, and the analysis of nematode survival was performed in liquid medium every 24 h until 120 h. Candida establishes a persistent lethal infection in the C. elegans intestinal tract. C. albicans and C. krusei were the most pathogenic species, whereas C. dubliniensis infection showed the lowest mortality. C. albicans was the only species with phospholipase activity, was the greatest producer of aspartyl proteinase and had a higher hemolytic activity. C. albicans and C. krusei caused higher mortality than the rest of the Candida species studied in the C. elegans model of candidiasis.

In Vitro Antifungal Susceptibility of Oral Candida Isolates from Patients Suffering from Caries and Chronic Periodontitis.

Caries and chronic periodontitis are common oral diseases where a higher Candida colonization is reported. Antifungal agents could be adjuvant drugs for the therapy of both clinical conditions. The aim of the current study has been to evaluate the in vitro activities of conventional and new antifungal drugs against oral Candida isolates from patients suffering from caries and/or chronic periodontitis. In vitro activities of amphotericin B, fluconazole, itraconazole, miconazole, nystatin, posaconazole and voriconazole against 126 oral Candida isolates (75 Candida albicans, 18 Candida parapsilosis, 11 Candida dubliniensis, six Candida guilliermondii, five Candida lipolytica, five Candida glabrata, four Candida tropicalis and two Candida krusei) from 61 patients were tested by the CLSI M27-A3 method. Most antifungal drugs were highly active, and resistance was observed in less than 5% of tested isolates. Miconazole was the most active antifungal drug, being more than 98% of isolates susceptible. Fluconazole, itraconazole, and the new triazoles, posaconazole and voriconazole, were also very active. Miconazole, fluconazole and voriconazole have excellent in vitro activities against all Candida isolates and could represent suitable treatment for a hypothetically adjunctive therapy of caries and chronic periodontitis.

Caries and Candida colonisation in adult patients in Basque Country (Spain).

Candida albicans is one of the most frequent pathogens of the oral cavity, as a major cause of opportunistic disease. Moreover, Candida could be a cofactor of common oral diseases, such as dental caries. The aim of this study was to analyse the oral yeast colonisation in adults with dental caries and to evaluate its relationship with this clinical entity. We studied 190 patients distributed into controls (58 patients) and patients with caries (132 patients). Oral samples were collected by oral rinse and cultured in a chromogenic agar. C. albicans was the most prevalent species isolated from oral specimens in both groups. Patients with caries had a greater Candida colonisation (74 patients, 56.1%), than persons without caries (18 patients, 31%, P < 0.01). Patients with caries were significantly more colonised by non-C. albicans species than individuals without caries (P = 0.006). Moreover, the diversity of Candida species was richer in patients suffering from caries. The odds ratio of the colonisation of patients with caries was 3.144 (95% CI 1.525-5.478). There is a significant clinical correlation between dental caries and oral Candida colonisation in adults.

Sertaconazole: an antifungal agent for the topical treatment of superficial candidiasis.

Sertaconazole is a useful antifungal agent against mycoses of the skin and mucosa, such as cutaneous, genital and oral candidiasis and tinea pedis. Its antifungal activity is due to inhibition of the ergosterol biosynthesis and disruption of the cell wall. At higher concentrations, sertaconazole is able to bind to nonsterol lipids of the fungal cell wall, increasing the permeability and the subsequent death of fungal cells. Fungistatic and fungicidal activities on Candida are dose-dependent. The antifungal spectrum of sertaconazole includes deramophytes, Candida, Cryptococcus, Malassezia and also Aspergillus, Scedosporium and Scopulariopsis. Sertaconazole also shows an antimicrobial activity against streptococci, staphylococci and protozoa (Trichomonas). In clinical trials including patients with vulvovaginal candidiasis, a single dose of sertaconazole produced a higher cure rate compared with other topical azoles such as econazole and clotrimazole, in shorter periods. Sertaconazole has shown an anti-inflammatory effect that is very useful for the relief of unpleasant symptoms.