7,10-Dihydroxy-8(E)-octadecenoic Acid Displays a Fungicidal Activity against Malassezia furfur

Microbial conversion of some natural unsaturated fatty acids can produce polyhydroxy fatty acids, giving them new properties, such as higher viscosity and reactivity. Pseudomonas aeruginosa has been intensively studied to produce a novel 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) from oleic acid and natural vegetable oils containing oleic acid. Recently, the antibacterial activities of DOD against food-borne pathogenic bacteria were reported; however, the action of such antibacterial properties against eucaryotic cells remains poorly known. In this study, we determined the antifungal activities of DOD against Malassezia furfur KCCM 12679 quantitatively and qualitatively. The antifungal activity of DOD against M. furfur KCCM 12679 was approximately five times higher than that of ketoconazole, a commercial antifungal agent. The MIC 90 value of DOD against M. furfur KCCM 12679 was 50 µg/mL. In addition, we confirmed that the antifungal property of DOD was exerted through fungicidal activity.

Regulatory Ability of Lactiplantibacillus plantarum on Human Skin Health by Counteracting In Vitro Malassezia furfur Effects

The skin serves as the first barrier against pathogen attacks, thanks to its multifunctional microbial community. Malassezia furfur is a commensal organism of normal cutaneous microflora but is also a cause of skin diseases. It acts on different cell pattern recognition receptors (TLRs, AhR, NLRP3 inflammasome) leading to cellular damage, barrier impairment, and inflammatory cytokines production. Lactobacillus spp. Is an endogenous inhabitant of healthy skin, and studies have proven its beneficial role in wound healing, skin inflammation, and protection against pathogen infections. The aim of our study is to demonstrate the ability of live Lactiplantibacillus plantarum to interfere with the harmful effects of the yeast on human keratinocytes (HaCat) in vitro. To enable this, the cells were treated with M. furfur, either alone or in the presence of L. plantarum. To study the inflammasome activation, cells require a stimulus triggering inflammation (LPS) before M. furfur infection, with or without L. plantarum. L. plantarum effectively counteracts all the harmful strategies of yeast, reducing the phospholipase activity, accelerating wound repair, restoring barrier integrity, reducing AhR and NLRP3 inflammasome activation, and, consequently, releasing inflammatory cytokines. Although lactobacilli have a long history of use in fermented foods, it can be speculated that they can also have health-promoting activities when topically applied.

Clinical data analysis of 86 patients with invasive infections caused by Malassezia furfur from a tertiary medical center and 37 studies

Objective

Malassezia furfur (M. furfur) is a lipophilic, conditionally pathogenic yeast that mainly causes skin infections, but the reports of related invasive infections are increasing. The aim of this study is to provide clinical data to assist physicians in the management of patients with invasive infections caused by M. furfur.

Methods

A case of pulmonary infection caused by M. furfur in a hematopoietic stem cell transplant patient for aplastic anemia was reported. In addition, the literature on invasive infection by M. furfur published in PubMed and Web of Science in English until 31 July 2022 was reviewed.

Results

Clinical data analysis of 86 patients (from 37 studies and our case) revealed that most of them were preterm (44.2%), followed by adults (31.4%). M. furfur fungemia occurred in 79.1% of the 86 patients, and 45 of them were clearly obtained from catheter blood. Other patients developed catheter-related infections, pneumonia, peripheral thromboembolism, endocarditis, meningitis, peritonitis and disseminated infections. Thirty-eight preterm infants had underlying diseases such as very low birth weight and/or multiple organ hypoplasia. The remaining patients had compromised immunity or severe gastrointestinal diseases. 97.7% of patients underwent invasive procedures and 80.2% received total parenteral nutrition (TPN). Fever, thrombocytopenia and leukocytosis accounted for 55.8%, 38.4% and 24.4% of patients with M. furfur invasive infections, respectively. 69.8% of the patients received antifungal therapy, mainly amphotericin B (AmB) or azoles. Of 84 patients with indwelling catheters, 58.3% underwent the removal of catheters. TPN were discontinued in 30 of 69 patients. The all-cause mortality of 86 patients was 27.9%.

Conclusions

M. furfur can cause a variety of invasive infections. These patients mostly occur in premature infants, low immunity and severe gastrointestinal diseases. Indwelling catheters and TPN infusion are major risk factors. AmB, l-AmB and azoles are the most commonly used agents, and simultaneous removal of the catheter and termination of TPN infusion are important for the treatment of M. furfur invasive infections.

Effects of Ultra-Weak Fractal Electromagnetic Signals on Malassezia furfur

Malassezia spp. are dimorphic, lipophilic fungi that are part of the normal human cutaneous commensal microbiome. However, under adverse conditions, these fungi can be involved in various cutaneous diseases. In this study, we analysed the effect of ultra-weak fractal electromagnetic (uwf-EMF) field exposure (12.6 nT covering 0.5 to 20 kHz) on the growth dynamics and invasiveness of M. furfur. The ability to modulate inflammation and innate immunity in normal human keratinocytes was also investigated. Using a microbiological assay, it was possible to demonstrate that, under the influence of uwf-EMF, the invasiveness of M. furfur was drastically reduced (d = 2.456, p < 0.001), while at the same time, its growth dynamic after 72 h having been in contact with HaCaT cells both without (d = 0.211, p = 0.390) and with (d = 0.118, p = 0.438) uwf-EM exposure, were hardly affected. Real-time PCR analysis demonstrated that a uwf-EMF exposure is able to modulate human-β-defensin-2 (hBD-2) in treated keratinocytes and at the same time reduce the expression of proinflammatory cytokines in human keratinocytes. The findings suggest that the underlying principle of action is hormetic in nature and that this method might be an adjunctive therapeutic tool to modulate the inflammatory properties of Malassezia in related cutaneous diseases. The underlying principle of action becomes understandable by means of quantum electrodynamics (QED). Given that living systems consist mainly of water and within the framework of QED, this water, as a biphasic system, provides the basis for electromagnetic coupling. The oscillatory properties of water dipoles modulated by weak electromagnetic stimuli not only affect biochemical processes, but also pave the way for a more general understanding of the observed nonthermal effects in biota.

Standardization of Galleria mellonella as an Infection Model for Malassezia furfur and Malassezia pachydermatis

Galleria mellonella larva has been widely exploited as an infection model for bacteria and fungi. Our laboratory uses this insect as a model for fungal infection caused by the genus Malassezia, in particular, systemic infections caused by Malassezia furfur and Malassezia pachydermatis, which are poorly understood. Here, we describe the G. mellonella larva inoculation process with M. furfur and M. pachydermatis and the posterior assessment of the establishment and dissemination of the infection in the larvae. This assessment was done through the evaluation of larval survival, melanization, fungal burden, hemocytes populations, and histological changes. This methodology allows for the identification of virulence patterns between Malassezia species and the impact of inoculum concentration and temperature.

Promising essential oils/plant extracts in the prevention and treatment of dandruff pathogenesis

BACKGROUND

Dandruff is a scalp malady affecting predominantly the male populace. Topical agents and synthetic drugs used for dandruff treatment have specific side effects including burning at the application site, depression, dizziness, headache, itching or skin rash, nausea, stomach pain, vision change, vomiting, discoloration of hair, dryness or oiliness of the scalp and increased loss of hair. Thus, essential oils and extracts from plants could be valuable in the treatment and prevention of dandruff.

AIM & OBJECTIVE

This review aims to highlight current findings in dandruff occurrence, its etiology, promising plant essential oils/extracts, and novel treatment strategies. The main emphasis has been given on the anti-dandruff effect of essential oils and plant extracts to disrupt microbial growth. The proposed mechanism (s) of action, novel approaches used to perk up its biopharmaceutical properties, and topical application have been discussed.

RESULTS

The literature survey was done, bibliographic sources and research papers were retrieved from different search engines and databases, including SciFinder, PubMed, NCBI, Scopus, and Google Scholar. The selection of papers was accomplished based on exclusion and inclusion criteria. The scalp of diverse populations revealed an association of dandruff with microbial symbiosis, including Staphylococcus, Propionibacterium, Malassezia, and Candida as the pathogens responsible for the cause of dandruff. Topical antifungals are considered as the first line of treatment for dandruff including azoles, with clotrimazole (1%), ketoconazole (2%), and miconazole (2%). Other commonly used therapies integrate benzoyl peroxide, coal tar, glycerin, zinc pyrithione, lithium succinate/gluconate, salicylic acid, selenium disulfide/sulfide, sodium sulfacetamide, etc. However, these medicaments and chemicals are known to cause specific side effects. Alternative therapies, including tea tree oil, thyme, Aloe vera, Mentha have been reported to demonstrate anti-dandruff activity by disrupting the microbial growth associated with dandruff formation.

CONCLUSION

Overall, this review explains the occurrence of dandruff, its etiology, and the potential applicability of promising plant essential oils/extracts, and their novel treatment strategies. Further studies based on pre-clinical and clinical research are essential before making any conclusion about its efficacy in humans.

Multiple Hybridization Events Punctuate the Evolutionary Trajectory of Malassezia furfur

Malassezia species are important fungal skin commensals and are part of the normal microbiota of humans and other animals. However, under certain circumstances these fungi can also display a pathogenic behavior. For example, Malassezia furfur is a common commensal of human skin and yet is often responsible for skin disorders but also systemic infections. Comparative genomics analysis of M. furfur revealed that some isolates have a hybrid origin, similar to several other recently described hybrid fungal pathogens. Because hybrid species exhibit genomic plasticity that can impact phenotypes, we sought to elucidate the genomic evolution and phenotypic characteristics of M. furfur hybrids in comparison to their parental lineages. To this end, we performed a comparative genomics analysis between hybrid strains and their presumptive parental lineages and assessed phenotypic characteristics. Our results provide evidence that at least two distinct hybridization events occurred between the same parental lineages and that the parental strains may have originally been hybrids themselves. Analysis of the mating-type locus reveals that M. furfur has a pseudobipolar mating system and provides evidence that after sexual liaisons of mating compatible cells, hybridization involved cell-cell fusion leading to a diploid/aneuploid state. This study provides new insights into the evolutionary trajectory of M. furfur and contributes with valuable genomic resources for future pathogenicity studies. IMPORTANCEMalassezia furfur is a common commensal member of human/animal microbiota that is also associated with several pathogenic states. Recent studies report involvement of Malassezia species in Crohn's disease, a type of inflammatory bowel disease, pancreatic cancer progression, and exacerbation of cystic fibrosis. A recent genomics analysis of M. furfur revealed the existence of hybrid isolates and identified their putative parental lineages. In this study, we explored the genomic and phenotypic features of these hybrids in comparison to their putative parental lineages. Our results revealed the existence of a pseudobipolar mating system in this species and showed evidence for the occurrence of multiple hybridization events in the evolutionary trajectory of M. furfur. These findings significantly advance our understanding of the evolution of this commensal microbe and are relevant for future studies exploring the role of hybridization in the adaptation to new niches or environments, including the emergence of pathogenicity.

Anti-inflammatory and Antimicrobial Activities of Fermented Ocimum sanctum Linn. Extracts Against Skin and Scalp Microorganisms

This study aimed to revealed anti-inflammatory and antimicrobial activities of fermented Ocimum sanctum Linn. (FE). The fermentation process with Lactobacillus plantarum was compared with the solvent extraction methods. Antimicrobial activity against the growth of Staphylococcus aureus , Staphylococcus epidermidis , Propionibacterium acnes , Candida albicans , and Malassezia furfur was investigated via broth dilution method. High performance thin layer chromatography was used to determine eugenol content. The anti-inflammation was investigated by means of nuclear factor kappa B (NF-κB) expression inhibition by Western blot analysis. FE yielded the highest amount (11.93% w/w), the highest eugenol content (39.3 ± 12.6% w/w), and the highest antimicrobial activities comparing to the extracts obtained from the solvent extractions. The fungal inhibition against M . furfur 656 was equivalent to that of ketoconazole. Furthermore, the bacterial inhibition on S. aureus and S. epidermidis was compared to that of Penicillin G at minimum inhibitory concentration (MIC) of 0.125 mg/mL and 0.25 mg/mL, respectively. Interestingly, FE had lower MIC and minimum bactericidal concentration against P. acnes than Penicillin G and also possessed comparable anti-inflammatory activity to indomethacin with the NF-κB suppression of 42.7 ± 4.6%. Therefore, FE are potentially natural anti-inflammation and antimicrobial agents for topical applications in the pharmaceutical and cosmetic industries.

Antifungal Effect of Antimicrobial Photodynamic Therapy Mediated by Haematoporphyrin Monomethyl Ether and Aloe Emodin on Malassezia furfur

Infectious dermatological diseases caused by Malassezia furfur are often chronic, recurrent, and recalcitrant. Current therapeutic options are usually tedious, repetitive, and associated with adverse effects. Alternatives that broaden the treatment options and reduce side effects for patients are needed. Antimicrobial photodynamic therapy (aPDT) is an emerging approach that is quite suitable for superficial infections. The aim of this study is to investigate the antimicrobial efficacy and effect of aPDT mediated by haematoporphyrin monomethyl ether (HMME) and aloe emodin (AE) on clinical isolates of M. furfur in vitro. The photodynamic antimicrobial efficacy of HMME and AE against M. furfur was assessed by colony forming unit (CFU) assay. The uptake of HMME and AE by M. furfur cells was investigated by fluorescence microscopy. Reactive oxygen species (ROS) probe and flow cytometry were employed to evaluate the intracellular ROS level. The effect of HMME and AE-mediated aPDT on secreted protease and lipase activity of M. furfur was also investigated. The results showed that HMME and AE in the presence of light effectively inactivated M. furfur cells in a photosensitizer (PS) concentration and light energy dose-dependent manner. AE exhibited higher antimicrobial efficacy against M. furfur than HMME under the same irradiation condition. HMME and AE-mediated aPDT disturbed the fungal cell envelop, significantly increased the intracellular ROS level, and effectively inhibited the activity of secreted protease and lipase of M. furfur cells. The results suggest that HMME and AE have potential to serve as PSs in the photodynamic treatment of dermatological diseases caused by M. furfur, but further ex vivo or in vivo experiments are needed to verify that they can meet the requirements for clinical practice.

Comparative analysis of Malassezia furfur mitogenomes and the development of a mitochondria-based typing approach

Malassezia furfur is a yeast species belonging to Malasseziomycetes, Ustilaginomycotina and Basidiomycota that is found on healthy warm-blooded animal skin, but also involved in various skin disorders like seborrheic dermatitis/dandruff and pityriasis versicolor. Moreover, Malassezia are associated with bloodstream infections, Crohn's disease and pancreatic carcinoma. Recent advances in Malassezia genomics and genetics have focused on the nuclear genome. In this work, we present the M. furfur mitochondrial (mt) genetic heterogenicity with full analysis of 14 novel and six available M. furfur mt genomes. The mitogenome analysis reveals a mt gene content typical for fungi, including identification of variable mt regions suitable for intra-species discrimination. Three of them, namely the trnK–atp6 and cox3–nad3 intergenic regions and intron 2 of the cob gene, were selected for primer design to identify strain differences. Malassezia furfur strains belonging to known genetic variable clusters, based on AFLP and nuclear loci, were assessed for their mt variation using PCR amplification and sequencing. The results suggest that these mt regions are excellent molecular markers for the typing of M. furfur strains and may provide added value to nuclear regions when assessing evolutionary relationships at the intraspecies level.

Antifungal activities of quince seed mucilage hydrogel decorated with essential oils of Nigella sativa, Citrus sinensis and Cinnamon verum

Background and Objectives:

Candidiasis and pityriasis versicolor are opportunistic fungal infections that are caused by Candida spp. and Malassezia spp. yeasts. Conventional drugs like azole and amino derivatives are known to treat fungal skin diseases. However, drawbacks like long-term side effects and drug resistance lead to investigate on antifungal properties of phytochemicals as an alternative to available synthetic drugs.

Materials and Methods:

The herbal nano hydrogel was successfully synthesized from Quince Seed extract followed by ultrasonic treatment and it has been formulated using a mixture of essential oils. We evaluated the antifungal in vitro assay for a mixture of essential oils in combination with herbal nano hydrogel against Candida albicans and Malasezia furfur strains by micro dilution method.

Results:

The results indicated that essential oils possess antifungal activity with the MIC value of 12.5 and 6.24 mg/ml against C. albicans and M. furfur, respectively. No fungicidal effect was reported for the herbal hydrogel before nanofabrication while it shown some antifungal activity after ultrasonic treatment for 5 and 10 minutes. As anticipated; the antifungal property of essential oil mixture was appreciably improved when it combined with herbal nano hydrogel where the highest level of inhibition was observed at concentration of 3.125 mg/ml for both strains. The loss in biological activity observed when the ultrasonic treatment on herbal nano hydrogel performed for longer time.

Conclusion:

The proposed plant-based nano formulation shown promising in vitro antifungal activities against C. albicans and M. furfur strains and its antifungal properties were comparable with commercially available agents like clotrimazole. The new formulation expected to be safe with minimum long-term side effects. Further investigations are underway to confirm the safety and the mechanism of the action of this new herbal formulation.

and Malassezia furfur isolates

Chlorogenic acid (CHA) and gallic acid (GA) are safe natural phenolic compounds that are used as enhancers of some drugs in influencing antioxidant, anticancer, and antibacterial activities. Among fungi, Candida spp. and Malassezia spp. are characterized by an increasing prevalence of multidrug resistance phenomena and by a high morbidity and mortality of their infections. No data are available about the efficacy of CHA and GA combined with azoles on the antifungal susceptibility and on the virulence of both fungi. Therefore, their antifungal and antivirulence effects have been tested in combination with fluconazole (FLZ) or ketoconazole (KTZ) on 23 Candida spp. and 8 M. furfur isolates. Broth microdilution chequerboard, time-kill studies, and extracellular enzymes (phospholipase and hemolytic) activities were evaluated, displaying a synergistic antifungal action between CHA or GA and FLZ or KTZ on C. albicans, C. bovina, and C. parapsilosis, and antagonistic antifungal effects on M. furfur and Pichia kudriavzevii (Candida krusei) isolates. The time-kill studies confirmed the chequerboard findings, showing fungicidal inhibitory effect only when the GA was combined with azoles on Candida strains. However, the combination of phenolics with azoles had no effect on the virulence of the tested isolates. Our study indicates that the combination between natural products and conventional drugs could be an efficient strategy for combating azole resistance and for controlling fungistatic effects of azole drugs.

In Vitro Azole and Amphotericin B Susceptibilities of Malassezia furfur from Bloodstream Infections Using E-Test and CLSI Broth Microdilution Methods

The number of reports of Malassezia furfur bloodstream infections is constantly increasing and there is a need for more simple antifungal susceptibility methods for their management. In this study, a total of 39 M. furfur isolates collected from hospitalized patients with fungemia were screened for antifungal susceptibility to azole and amphotericin B (AmB) using Clinical and Laboratory Standards Institute broth microdilution (CLSI BMD) and E-test in Sabouraud dextrose agar + 1% Tween80 (SDAt) and mDixon agar (DIX). Essential agreement (EA) and discrepancies between the two methods were evaluated after 48 h and 72 h reading times. Itraconazole (ITZ) and posaconazole (POS) displayed the lowest MIC values whereas fluconazole (FLZ) and AmB the highest, regardless of the methods and the reading time. The EA between BMD was >95% for FLZ and voriconazole (VOR) regardless of the media in the E-tests and reading time. The EA between BMD with E-test for AmB was >97% only when E-test in SDAt was used. The EA between BMD and E-test for ITZ and POS varied according to the media in E-test procedures and the reading time and was higher than 66.6% (POS) or 72% (ITZ) only when SABt was used. Substantial discrepancies for ITZ and POS were >5.1% regardless of the media and the reading time. This study suggests that the E-test in SABt represents an alternative method to CLSI BMD to evaluate the susceptibility of M. furfur to FLZ, VOR and AmB and not for ITZ and POS.

Galleria mellonella as a Novelty in vivo Model of Host-Pathogen Interaction for Malassezia furfur CBS 1878 and Malassezia pachydermatis CBS 1879

Malassezia furfur and Malassezia pachydermatis are lipophilic and lipid dependent yeasts, associated with the skin microbiota in humans and domestic animals, respectively. Although they are commensals, under specific conditions they become pathogens, causing skin conditions, such as pityriasis versicolor, dandruff/seborrheic dermatitis, folliculitis in humans, and dermatitis and otitis in dogs. Additionally, these species are associated with fungemia in immunocompromised patients and low-weight neonates in intensive care units with intravenous catheters or with parenteral nutrition and that are under-treatment of broad-spectrum antibiotics. The host-pathogen interaction mechanism in these yeasts is still unclear; for this reason, it is necessary to implement suitable new host systems, such as Galleria mellonella. This infection model has been widely used to assess virulence, host-pathogen interaction, and antimicrobial activity in bacteria and fungi. Some advantages of the G. mellonella model are: (1) the immune response has phagocytic cells and antimicrobial peptides that are similar to those in the innate immune response of human beings; (2) no ethical implications; (3) low cost; and (4) easy to handle and inoculate. This study aims to establish G. mellonella as an in vivo infection model for M. furfur and M. pachydermatis. To achieve this objective, first, G. mellonella larvae were first inoculated with different inoculum concentrations of these two Malassezia species, 1.5 × 10⁶ CFU/mL, 1.5 × 10⁷ CFU/mL, 1.5 × 10⁸ CFU/mL, and 11.5 × 10⁹ CFU/mL, and incubated at 33 and 37°C. Then, for 15 days, the mortality and melanization were evaluated daily. Finally, the characterization of hemocytes and fungal burden assessment were as carried out. It was found that at 33 and 37°C both M. furfur and M. pachydermatis successfully established a systemic infection in G. mellonella. M. pachydermatis proved to be slightly more virulent than M. furfur at a temperature of 37°C. The results suggest that larvae mortality and melanization is dependent on the specie of Malassezia, the inoculum concentration and the temperature. According to the findings, G. mellonella can be used as an in vivo model of infection to conduct easy and reliable approaches to boost our knowledge of the Malassezia genus.

In Vitro Antimicrobial Activity of Frankincense Oils from Boswellia sacra Grown in Different Locations of the Dhofar Region (Oman)

Frankincense essential oils from Boswellia sacra have been commonly used to treat microbial infections from as early as the 11th century. The main feature of the plant is its gum resin, from which it is possible to obtain essential oils. In the present study, we focused on the comparative study of the oils extracted from the resins of three different Boswellia sacra cultivars (Najdi, Sahli and Houjri). From each of frankincense resin three successive essential oil samples (Grade 1, Grade 2, Grade 3) were obtained. Houjri gum resin gave the lowest percentage (5%) of total essential oil content but showed the maximum number of volatile components in all three grades. Najdi Grade 2 essential oil showed a minimum inhibitory concentration (MIC) of 52 mg/mL toward relevant pathogens Staphylococcus aureus and Pseudomonasaeruginosa, and samples from Grade 2 of Sahily and Houjiri were particularly active against a dermatological strain Propionibacterium acnes, displaying MIC values of 0.264 and 0.66 mg/mL, respectively. Data obtained from in vitro studies showed that all essential oils had a significant antifungal effect against Candida albicans and Malassezia furfur, showing MIC values ranging from 54.56 to 0.246 mg/mL. This work aims to increase the number of substances available in the fight against pathogens and to combat the phenomenon of antibiotic resistance, encouraging the use of alternative resources, especially in non-clinical settings (farms, food processing, etc.).

Advancing Functional Genetics Through Agrobacterium-Mediated Insertional Mutagenesis and CRISPR/Cas9 in the Commensal and Pathogenic Yeast Malassezia

Malassezia encompasses a monophyletic group of basidiomycetous yeasts naturally found on the skin of humans and other animals. Malassezia species have lost genes for lipid biosynthesis, and are therefore lipid-dependent and difficult to manipulate under laboratory conditions. In this study, we applied a recently-developed Agrobacterium tumefaciens-mediated transformation protocol to perform transfer (T)-DNA random insertional mutagenesis in Malassezia furfur A total of 767 transformants were screened for sensitivity to 10 different stresses, and 19 mutants that exhibited a phenotype different from the wild type were further characterized. The majority of these strains had single T-DNA insertions, which were identified within open reading frames of genes, untranslated regions, and intergenic regions. Some T-DNA insertions generated chromosomal rearrangements while others could not be characterized. To validate the findings of our forward genetic screen, a novel clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system was developed to generate targeted deletion mutants for two genes identified in the screen: CDC55 and PDR10 This system is based on cotransformation of M. furfur mediated by A. tumefaciens, to deliver both a CAS9-gRNA construct that induces double-strand DNA breaks and a gene replacement allele that serves as a homology-directed repair template. Targeted deletion mutants for both CDC55 and PDR10 were readily generated with this method. This study demonstrates the feasibility and reliability of A. tumefaciens-mediated transformation to aid in the identification of gene functions in M. furfur, through both insertional mutagenesis and CRISPR/Cas9-mediated targeted gene deletion.

Malassezia interaction with a reconstructed human epidermis: Keratinocyte immune response

The immediate immune response developed by the keratinocytes against Malassezia yeasts has been addressed yielding conflicting results. This study aims the assessment of cytokines and antimicrobial peptides gene expression elicited by M. sympodialis and M. furfur once in contact with a reconstructed human epidermis. A yeast suspension was prepared in RPMI 1640 medium (Sigma-Aldrich, St. Louis, MO) supplemented with Tween 60 and oleic acid to obtain approximately 1 × 10⁶ cells in a volume of 100 μL. Clinical isolates of M. sympodialis (from pityriasis versicolor) and M. furfur (from seborrhoeic dermatitis) were inoculated, separately, onto a reconstructed human epidermis. A distinct expression pattern was found between the two tested species, with a tendency for overexpression of pro-inflammatory cytokines very soon after infection, whereas no significant expression or gene downregulation was often noticed following 24 and 48 h of incubation. A possible Malassezia species-dependent immune response pattern is highlighted.

Antifungal activity of Mongolian medicinal plant extracts

The in vitro antifungal activity of extracts obtained from 14 medicinal plants of the mongolian flora were investigated by measuring their minimal inhibitory concentration (MIC) against fungi cause of cutaneous diseases such as Candida species, dermatophytes and Malassezia furfur. Among the species examined, Stellaria dichotoma L., Scutellaria scordifolia L. Aquilegia sibirica Fisch. Et Schrenk. and Hyoscyamus niger L. extracts demonstrated antifungal activity against all studied fungi. In particular, S. scordifolia L. methanol extract, obtained at room temperature, showed the best activity against Candida spp., Malassezia furfur and dermatophytes with GMMIC₅₀ values of 22 µg/mL, 64 µg/mL and 32 µg/mL, respectively. The flavones, luteolin and apigenin, identified in S. scordifolia extracts, and rutin identified in S. dichotoma and Hyoscyamus niger L. extracts, could be responsible of the observed antifungal activity.

Extracellular vesicles derived from Malassezia furfur stimulate IL-6 production in keratinocytes as demonstrated in in vitro and in vivo models

BACKGROUND

Malassezia is one of the commensal microorganisms colonized on human skin and has been shown to be related to several inflammatory cutaneous disorders. Previous studies indicated that Malassezia. sympodialis (M. sympodialis) can produce extracellular vesicles, however, the immunoregulatory function of Malassezia extracellular vesicles on keratinocytes has not been studied.

OBJECTIVE

To investigate the extracellular vesicular production capability of Malassezia. furfur (M. furfur) and examine their immunoregulatory effects both in vitro and in vivo.

METHODS

Extracellular vesicles derived from M. furfur were isolated by sequential ultracentrifugation procedure. Their structure and diameter were determined by negative stain TEM and NTA, respectively. Confocal microscopy was used to visualize the internalization of these nanoparticles into HaCaT cells and mice epidermal keratinocytes. The expressions of inflammatory cytokines were screened using PCR Array assay and validated in vitro by qPCR and ELISA assays. In vivo cytokine production was measured by the IHC method. The role of NF-κB in such process was evaluated in HaCaT cells by western blot assay.

RESULTS

Our results showed that M. furfur produced ovoid-shaped nanoparticles, which could be then internalized into HaCaT cells, as well as mice epidermal keratinocytes. IL-6 expression was significantly enhanced in response to extracellular vesicular stimulation both in vitro and in vivo, in which process the activation of NF-κB was involved.

CONCLUSION

M. furfur has the ability to release extracellular vesicles, which can be internalized into keratinocytes and promote the production of IL-6 with the involvement of NF-κB dependent pathway. Such findings reveal some important new insights into Malassezia pathogenesis and therapy.

Psoriasis with a dirt-adherent: A rare case report

Cutaneous dirt-adherent disease (CDAD) is a rare psychogenic dermatosis mainly occurring in young Japanese and Chinese women. It mainly occurs on cheeks, forehead, nipple, mammary areola and around mammary areola. To our knowledge, this is the first case of CDAD with the skin lesion of psoriasis rupioides to be reported. In our case, the patient, a 43-year-old Chinese man presented with thick, yellowish-brown adherent crusts on his face with severe painful 6-days duration. Histopathologic image: Parakeratosis, the epidermis demonstrates regular acanthosis with some thinning of the suprapapillary plates, neutrophils exocytosis are noted. As for the histopathologic diagnosis in his right crus, combined with the clinical manifestation of rupioides-shaped crusts, film phenomenon and Auspitz's sign, we considered Psoriasis rupioide.

Biofilm, adherence, and hydrophobicity as virulence factors in Malassezia furfur

Malassezia species are natural inhabitants of the healthy skin. However, under certain conditions, they may cause or exacerbate several skin diseases. The ability of this fungus to colonize or infect is determined by complex interactions between the fungal cell and its virulence factors. This study aims to evaluate "in vitro" the hydrophobicity levels, the adherence on a plastic surface and the biofilm formation of 16 clinical isolates of Malassezia furfur. Cellular surface hydrophobicity (CSH) levels were determined by two-phase system. The biofilm formation was determined by tetrazolium salt (XTT) reduction assay and by Scanning Electron Microscopy (SEM). Results showed many isolates were hydrophobic, adherent, and producers of biofilm on abiotic surfaces with different capacity. SEM observations confirmed an abundant extracellular matrix after 48 h of biofilm formation. About 63% of strains with high production of biofilm showed medium to high percentage of hydrophobicity and/or adherence. In addition, it has been demonstrated a correlation between hydrophobicity, adherence, and biofilm formation in about 60% of strains examined. These important virulence factors could be responsible of this yeast changing from a commensal to a pathogenic status.

Efficacy of modified Leeming-Notman media in a resazurin microtiter assay in the evaluation of in-vitro activity of fluconazole against Malassezia furfur ATCC 14521

BACKGROUND

Malassezia furfur is lipodependent yeast like fungus that causes superficial mycoses such as pityriasis versicolor and dandruff. Nevertheless, there are no standard reference methods to perform susceptibility test of Malassezia species yet.

AIMS

Therefore, in this study, we evaluated the optimized culture medium for growth of this lipophilic yeast using modified leeming-Notman agar and colorimetric resazurin microtiter assay to assess antimycotic activity of fluconazole against M. furfur.

RESULTS

The result showed that these assays were more adjustable for M. furfur with reliable and reproducible MIC end-point, by confirming antimycotic activity of fluconazole with MIC of 2μg/ml.

CONCLUSION

We conclude that this method is considered as the rapid and effective susceptibility testing of M. furfur with fluconazole antifungal activity.

[In vitro antifungal activity of azoles and amphotericin B against Malassezia furfur by the CLSI M27-A3 microdilution and Etest® methods]

BACKGROUND

Malassezia furfur is a human skin commensal yeast that can cause skin and opportunistic systemic infections. Given its lipid dependant status, the reference methods established by the Clinical and Laboratory Standards Institute (CLSI) to evaluate antifungal susceptibility in yeasts are not applicable.

AIMS

To evaluate the in vitro susceptibility of M. furfur isolates from infections in humans to antifungals of clinical use.

METHODS

The susceptibility profile to amphotericin B, itraconazole, ketoconazole and voriconazole of 20 isolates of M. furfur, using the broth microdilution method (CLSI M27-A3) and Etest^®, was evaluated.

RESULTS

Itraconazole and voriconazole had the highest antifungal activity against the isolates tested. The essential agreement between the two methods for azoles antifungal activity was in the region of 60-85% and the categorical agreement was around 70-80%, while the essential and categorical agreement for amphotericin B was 10%.

CONCLUSIONS

The azoles were the compounds that showed the highest antifungal activity against M. furfur, as determined by the two techniques used; however more studies need to be performed to support that Etest^® is a reliable method before its implementation as a routine clinical laboratory test.

Ketoconazole inhibits Malassezia furfur morphogenesis in vitro under filamentation optimized conditions

Malassezia furfur, a constituent of the normal human skin flora, is an etiological agent of pityriasis versicolor, which represents one of the most common human skin diseases. Under certain conditions, both exogenous and endogenous, the fungus can transition from a yeast form to a pathogenic mycelial form. To develop a standardized medium for reproducible production of the mycelial form of M. furfur to develop and optimize susceptibility testing for this pathogen, we examined and characterized variables, including kojic acid and glycine concentration, agar percentage, and pH, to generate a chemically defined minimal medium on which specific inoculums of M. furfur generated the most robust filamentation. Next, we examined the capacity of ketoconazole to inhibit the formation of M. furfur mycelial form. Both low and high, 0.01, 0.05 and 0.1 µg/ml concentrations of ketoconazole significantly inhibited filamentation at 11.9, 54.5 and 86.7%, respectively. Although ketoconazole can have a direct antifungal effect on both M. furfur yeast and mycelial cells, ketoconazole also has a dramatic impact on suppressing morphogenesis. Since mycelia typified the pathogenic form of Malassezia infection, the capacity of ketoconazole to block morphogenesis may represent an additional important effect of the antifungal.

Anti-Dermatophyte and Anti-Malassezia Activity of Extracts Rich in Polymeric Flavan-3-ols Obtained from Vitis vinifera Seeds

Several human skin diseases are associated with fungi as dermatophytes and Malassezia. Skin mycoses are increasing and new alternatives to conventional treatments with improved efficacy and/or safety profiles are desirable. For the first time, the anti-dermatophytes and the anti-Malassezia activities of Vitis vinifera seed extracts obtained from different table and wine cultivars have been evaluated. Geometric minimal inhibitory concentration ranged from 20 to 97 µg/mL for dermatophytes and from 32 to 161 µg/mL for Malassezia furfur. Dried grape seed extracts analyzed by HPLC/DAD/ESI/MS showed different quali-quantitative compositions in terms of monomeric and polymeric flavan-3-ols. The minimal inhibitory concentrations for Trichophyton mentagrophytes and for M. furfur were inversely correlated with the amount of the polymeric fraction (r = -0.7639 and r = -0.7228, respectively). Differently, the antifungal activity against T. mentagrophytes was not correlated to the content of flavan-3-ol monomers (r = 0.2920) and only weakly correlated for M. furfur (r = -0.53604). These results suggest that extracts rich in polymeric flavan-3-ols, recovered from V.  vinifera seeds, could be used for the treatment of skin fungal infections. Copyright © 2016 John Wiley & Sons, Ltd.

Size- and shape-dependent clinical and mycological efficacy of silver nanoparticles on dandruff

Dandruff is a prominent scalp problem caused by the growth of fungus Malassezia furfur, potentially cascading into dermal inflammation, itching, and tissue damage. The present work outlines a detailed analysis of the treatment of scalp infection using silver nanomaterials (Ag NMs), and focuses on biocidal activity owing to manipulation of size, shape, and structure. Monodisperse silver spherical nanoparticles (NPs) and nanorods (NRs) were synthesized by chemical routes that were characterized using analytical and spectroscopic techniques. Ag NMs demonstrated enhanced biocidal tendencies compared to market available drugs, itracanozole and ketoconazole, showing greater zones of inhibition. The obtained 20 nm and 50 nm spherical-shaped NPs and 50 nm NRs showed concentration-, size-, and shape-dependent antifungal activity, with 20 nm spherical-shaped NPs exhibiting excellent potency. Minimum inhibitory concentration for 20 nm was lowest at 0.2 mg/mL in comparison to 0.3 mg/mL for NRs. Primary irritation index was 0.33 and 0.16 for 20 nm and 50 nm spherical-shaped NPs, respectively, while 50 nm rod-shaped NMs exhibited negligible redness. An in vivo model for M. furfur infection was generated by passing fungi subcutaneously in rats' skin. Again, 20 nm particles showed best normalization of skin after 10 days on regular dosing, in comparison with bigger and rod-shaped particles. The statistical clinical score was highest for Ag nanorods, followed by 50 nm Ag NPs-treated animals. It was observed that 20 nm spherical particles exhibited the lowest score (0) compared with others as well as with antifungal drugs. Biochemical analysis performed by checking antioxidant enzymatic activities indicated tissue repair and normalization of enzymes and protein concentration by Ag NPs.

In vitro antifungal activity of extracts obtained from Hypericum perforatum adventitious roots cultured in a mist bioreactor against planktonic cells and biofilm of Malassezia furfur

Xanthone-rich extracts from Hypericum perforatum root cultures grown in a Mist Bioreactor as antifungal agents against Malassezia furfur. Extracts of Hypericum perforatum roots grown in a bioreactor showed activity against planktonic cells and biofilm of Malassezia furfur. Dried biomass, obtained from roots grown under controlled conditions in a ROOTec mist bioreactor, has been extracted with solvents of increasing polarity (i.e. chloroform, ethyl acetate and methanol). The methanolic fraction was the richest in xanthones (2.86 ± 0.43 mg g(-1) DW) as revealed by HPLC. The minimal inhibitory concentration of the methanol extract against M. furfur planktonic cells was 16 μg mL(-1). The inhibition percentage of biofilm formation, at a concentration of 16 μg mL(-1), ranged from 14% to 39%. The results show that H. perforatum root extracts could be used as new antifungal agents in the treatment of Malassezia infections.

Pityriazepin and other potent AhR ligands isolated from Malassezia furfur yeast

Malassezia furfur yeast strains isolated from diseased human skin preferentially biosynthesize indole alkaloids which can be detected in the human skin and are highly potent activators of the aryl hydrocarbon receptor (AhR) and AhR-dependent gene expression. Chemical analysis of an EtOAc extract of a M. furfur strain obtained from diseased human skin and grown on l-tryptophan agar revealed several known AhR active tryptophan metabolites along with a previously unidentified compound, pityriazepin. While its structure resembled that of the known alkaloid pityriacitrin, the comprised pyridine ring had been transformed into an azepinone. The indoloazepinone scaffold of pityriazepin is extremely rare in nature and has only been reported once previously. Pityriazepin, like the other isolated compounds, was found to be a potent activator of the AhR-dependent reporter gene assay in recombinant cell lines derived from four different species, although significant species differences in relative potency were observed. The ability of pityriazepin to competitively bind to the AhR and directly stimulate AhR DNA binding classified it as a new naturally-occurring potent AhR agonist. M. furfur produces an expanded collection of extremely potent naturally occurring AhR agonists, which produce their biological effects in a species-specific manner.

Bloodstream infections by Malassezia and Candida species in critical care patients

Despite being considered an emerging yeast related to immunocompromised individuals, severe infections by Malassezia furfur have not been evaluated. During a one-year survey on yeasts fungemia, 290 neonatal and 17 pediatric patients with intravascular catheters, lipid parenteral nutrition, prolonged ward stay, and surgery were enrolled. In addition, the origin of the infection was investigated by swabbing hand skin of patients, parents, and healthcare workers and medical devices. All biological specimens and swabs were cultured on Sabouraud dextrose agar and Dixon agar. The yeasts identification was based on morphological and biochemical features and by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and confirmed by sequencing the internal transcribed spacer of nuclear ribosomal DNA. A higher prevalence of M. furfur (2.1%) over Candida spp. (1.4%) caused bloodstream infections (BSIs). Twelve fungemia episodes were recorded: 2 by M. furfur in a pediatric ward and 10 in a neonatal intensive care unit (6 caused by M. furfur and 4 by Candida spp.). M. furfur was also isolated from the skin of all patients with BSIs, from the hand skin of a parent, and from an incubator surface and sheet. Patients with Candida spp. and M. furfur BSIs were successfully treated with intravenous liposomal Amphotericin B. These findings highlight the need for a more accurate etiological diagnosis in high-risk patients by adding lipid-supplemented culture media for Malassezia in the current mycological routine as the clinical features, patient management, and outcomes in both Candida and Malassezia fungemia do not differ.

Identification and speciation of malassezia in patients clinically suspected of having pityriasis versicolor

Background:

Malassezia is a lipid-dependent yeast known to cause Pityriasis versicolor, a chronic, recurrent superficial infection of skin and present as hypopigmented or hyperpigmented lesions on areas of skin. If not diagnosed and treated, it may lead to disfigurement of the areas involved and also result in deep invasive infections.

Aim:

The aim of the present study was to identify and speciate Malassezia in patients clinically suspected of having Pityriasis versicolor.

Materials and Methods:

Total 139 patients suspected of having Pityriasis versicolor were evaluated clinically and diagnosis was done by Wood's lamp examination, confirmed mycologically by using KOH, cultivation on Sabouraud's dextrose agar and modified Dixon agar at a tertiary care hospital in Mumbai. The total duration of study was 12 months.

Results:

Majority of the patients were males (59.71%) in the age group of 21-30 years (33.81%) who were students (30.21%) by profession. The incidence of Malassezia in Pityriasis versicolor was 50.35%. The most common isolate was M. globosa (48.57%), followed by M. furfur (34.28%). Majority of the patients had hypopigmented lesions, with M. globosa as the predominant isolate. Neck was the most common site affected; 88.48% were Wood's lamp positive of which 56.91% of Malassezia isolates grew on culture. KOH mount was positive in 82.01% of which 61.40% Malassezia isolates grew on culture.

Conclusions:

The procedure of culture and antifungal testing is required to be performed as different species of Malassezia are involved in Pityriasis versicolor and susceptibility is different among different species. Thus, it would help to prevent recurrences and any systemic complications.

The Effect of Detergents on the Morphology and Immunomodulatory Activity of Malassezia furfur

BACKGROUND

Several workers have found that Malassezia are capable of suppressing cytokine release and downregulating the phagocytic function of monocytes. But lipid-depleted Malassezia furfur (M. furfur) extracts have also been shown to induce increased production of TNF-alpha, IL-6 and IL-1beta in monocytes. We thought that the detergents in shampoos or soaps could change the composition of the lipid in the M. furfur cell wall.

OBJECTIVE

We studied whether detergents affect the morphology of M. furfur and if the inflammatory cytokine profiles change in the monocytes treated with detergent-treated M. furfur.

METHODS

Commonly used detergents such as sodium lauryl sulfate, ammonium lauryl sulfate and tween-80 were respectively added to the modified Leeming-Notman's media. M. furfur was cultivated in each media (detergent-added or untreated). Thereafter, the surface morphology of the yeast was evaluated by scanning and transmission electron microscopy. The cytokine profiles of monocytes, which were treated by M. furfur with or without detergents, were also evaluated.

RESULTS

The detergent-treated M. furfur were similar to the lipid-extracted form of M. furfur on the electron microscopic study, with a recessed, withered surface and with thinner and rather electron transparent cell walls than the detergent-untreated M. furfur. The levels of TNF-alpha were higher in monocytes treated with detergent-treated Malassezia than that in the monocytes treated with the detergent-untreated Malassezia (p<0.05).

CONCLUSION

According to the findings in this study, it could be inferred that the detergents in shampoos or soaps affect the lipid layers of the Malassezia cell wall and these lipid-extracted Malassezia induce or aggravate some inflammatory conditions. But to correlate the relationship between detergents and Malassezia-associated diseases, in vivo experiments that will focus on short-term contact with detergents in real life conditions should be done.

In vitro Activity of Celery Essential Oil against Malassezia furfur

Antifungal activity of celery essential oil against Malassezia furfur was investigated using broth microdilution and vapor contact methods. Potent antifungal activity was evident using both methods. Fungicidal activity was revealed in the vapor contact method.

Neonatal rectal colonization with Malassezia furfur

Malassezia furfur and Candida albicans are fungal pathogens which have been recognized with increasing frequency as agents of mortality and serious morbidity in neonatal intensive care unit patients. A longitudinal study of oral, rectal and umbilical colonization by these organisms of newborns admitted to a neonatal intensive care unit within 24 h of birth was undertaken. Of 71 infants followed for a minimum of 10 days, 24 were colonized with M furfur and 12 with C albicans during the first 10 days of life. The lower gastrointestinal tract was found to be the most common colonization site for both organisms. Statistically significant (P<0.05) inverse associations were demonstrated between gestational age and risk of colonization with either organism at any site, and between birthweight or gestational age and risk of rectal colonization with either organism. Antibiotics were associated with a relative risk colonization of 4.06 (P=0.06) with either organism at any site. It is concluded that M furfur and C albicans are common colonizing organisms in a neonatal intensive care unit setting and are most frequently harboured in the lower gastrointestinal tract. M furfur, recently implicated as a systemic pathogen in this population, has not been previously recognized as a gastrointestinal commensal organism. The relationship between colonization and invasive fungal disease, and potential roles for preventive strategies, remain to be elucidated.