Exploring the antifungal activity and mechanism of action of Zingiberaceae rhizome extracts against Malassezia furfur.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhizomes from members of Zingiberaceae have long been used in Thai traditional medicine to treat cutaneous fungal infections, including Malassezia-related skin disorders. Alpinia galanga, Curcuma longa, Zingiber cassumunar, and Zingiber officinale are particularly popular in folk remedies. AIM OF THE STUDY: On account of the application background in traditional medicine, the present study aims to screen and determine the composition and possible mechanism of the rhizome extracts of selected Zingiberaceae and corresponding fractions against M. furfur. MATERIALS AND METHODS: All solvent extracts (ethanol, methanol, and n-hexane) obtained from each plant were screened for anti-Malassezia activity by agar disc diffusion assay. The MIC and MFC values of the potent rhizome extract and its bioactive fraction isolated by TLC were determined using broth dilution assay followed by chemical characterization using GC-MS. The anti-Malassezia mechanism was investigated by macroscopic and microscopic observation of cells grown in the yeast phase and hyphal phase. RESULTS: The primary screening results showed that the n-hexane extract from A. galanga possessed the most significant anti-Malassezia activity. The MIC and MFC values of this extract were in a range of 0.04-0.08 mg/mL and 0.04-0.16 mg/mL, respectively. The TLC purification of the n-hexane extract from A. galanga gave a total of nine fractions, of which only a single exhibited anti-Malassezia activity. The GC-MS analysis of the rhizome extract and the derivative fraction revealed that the major constituents were (2,6-dimethylphenyl)borate followed by a trace content of 1,8-cineol and hydrocarbons. For the antifungal mechanism of the fraction, treatments of the fraction led to morphological changes in cell size and shape, exerted massive vacuoles in yeast form, and inhibited the transition to hyphae but not likely affected chitin contents of the cell wall of M. furfur. CONCLUSIONS: According to the results, the n-hexane extract of A. galanga rhizome exhibits promising anti-Malassezia potential. The inhibitory effect on virulent hyphal growth supports that A. galanga is a valuable source of natural antifungal agents for further pharmaceutical research.

Effect of zinc pyrithione shampoo treatment on skin commensal Malassezia.

Malassezia restricta and Malassezia globosa are lipid dependent commensal yeasts associated with dandruff. Antifungal actives such as zinc pyrithione are commonly used in antidandruff shampoos, although their efficacy is not clearly demonstrated. In this study, we assessed the efficacy of antifungal treatments on scalp Malassezia via a combination of culturomic and genomic detection methods. Zinc pyrithione inhibited Malassezia growth at low minimum inhibitory concentrations (MICs). In a longitudinal pilot study, quantitative polymerase chain reaction (qPCR) analysis showed a decrease in M. restricta on the scalp after zinc pyrithione treatment. These findings validate the antifungal efficacy of zinc pyrithione as a dandruff treatment. LAY ABSTRACT: Malassezia yeasts are associated with dandruff and seborrheic dermatitis. Zinc pyrithione is effective against Malassezia growth in vitro and when tested on human skin as a shampoo. These findings will be useful for investigating the role of Malassezia in skin microbiome intervention studies.

Conventional therapy and new antifungal drugs against Malassezia infections.

Malassezia yeasts are commensal microorganisms occurring on the skin of humans and animals causing dermatological disorders or systemic infections in severely immunocompromised hosts. Despite attempts to control such yeast infections with topical and systemic antifungals, recurrence of clinical signs of skin infections as well as treatment failure in preventing or treating Malassezia furfur fungemia have been reported most likely due to wrong management of these infections (e.g., due to early termination of treatment) or due to the occurrence of resistant phenomena. Standardized methods for in vitro antifungal susceptibility tests of these yeasts are still lacking, thus resulting in variable susceptibility profiles to azoles among Malassezia spp. and a lack of clinical breakpoints. The inherent limitations to the current pharmacological treatments for Malassezia infections both in humans and animals, stimulated the interest of the scientific community to discover new, effective antifungal drugs or substances to treat these infections. In this review, data about the in vivo and in vitro antifungal activity of the most commonly employed drugs (i.e., azoles, polyenes, allylamines, and echinocandins) against Malassezia yeasts, with a focus on human bloodstream infections, are summarized and their clinical implications are discussed. In addition, the usefulness of alternative compounds is discussed.

New Therapeutic Candidates for the Treatment of Malassezia pachydermatis -Associated Infections.

The opportunistic pathogen Malassezia pachydermatis causes bloodstream infections in preterm infants or individuals with immunodeficiency disorders and has been associated with a broad spectrum of diseases in animals such as seborrheic dermatitis, external otitis and fungemia. The current approaches to treat these infections are failing as a consequence of their adverse effects, changes in susceptibility and antifungal resistance. Thus, the identification of novel therapeutic targets against M. pachydermatis infections are highly relevant. Here, Gene Essentiality Analysis and Flux Variability Analysis was applied to a previously reported M. pachydermatis metabolic network to identify enzymes that, when absent, negatively affect biomass production. Three novel therapeutic targets (i.e., homoserine dehydrogenase (MpHSD), homocitrate synthase (MpHCS) and saccharopine dehydrogenase (MpSDH)) were identified that are absent in humans. Notably, L-lysine was shown to be an inhibitor of the enzymatic activity of MpHCS and MpSDH at concentrations of 1 mM and 75 mM, respectively, while L-threonine (1 mM) inhibited MpHSD. Interestingly, L- lysine was also shown to inhibit M. pachydermatis growth during in vitro assays with reference strains and canine isolates, while it had a negligible cytotoxic activity on HEKa cells. Together, our findings form the bases for the development of novel treatments against M. pachydermatis infections.

Comparative study between topically applied irradiated human amniotic membrane in combination with tea tree oil versus topical tioconazole in pityraisis versicolor treatment.

Pityriasis versicolor (PV) is a chronic skin disease caused by virulence activities of Malassezia, a genus of skin-associated yeasts. Traditionally, Tioconazole is used as a topical antifungal for curing PV. Previous investigations cited that human amniotic membrane (HAM), a placental tissue, has antimicrobial and anti-inflammatory activities and is useful as a dressing for healing skin lesions. Moreover, tea tree oil (TTO) has a potent antifungal efficacy. This clinical trial aims to achieve an alternative therapeutic treatment able to kill Malassezia and heal PV lesions using TTO-saturated HAM (TOSHAM), with little application times. This study subjected 120 patients with hypopigmented or hyperpigmented PV lesions; half patients were treated weekly with TOSHAM compared with the others who applying 1% Tioconazole cream daily as a traditional treatment. Microbiological evaluation of in vitro fungicidal activity of TOSHAM versus Tioconazole was carried out against Malassezia furfur culture. The clinical outcomes of this study proved the superior activity of TOSHAM to heal PV lesions than Tioconazole; this was in harmony with microbiological findings. This study approached a novel therapeutic treatment of PV with great outcomes by using TOSHAM.

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.

Antifungal activity of different essential oils against Malassezia pathogenic species.

ETHNOPHARMACOLOGICAL RELEVANCE: Plants produce essential oils in response to physiological stresses, pathogen attacks and ecological factors. Nowadays, they are recognized as defence compounds and attractors of pollinators. Essential oils have been traditionally used in the past years in various cultures for medicinal and health purposes. In recent times due to their well-documented antimicrobial activities, essential oils have consolidated their use in raw and processed food preservation, health and clinical uses. AIMS OF THE REVIEW: The potential activity of essential oils against the largely diffused Malassezia species on the human skin, which can cause common infections or exacerbate multiple skin disorders, such as P. versicolor, folliculitis, seborrheic dermatitis and dandruff, atopic dermatitis and psoriasis. MATERIALS AND METHODS: Information on essential oils activity against Malassezia species was obtained from published materials, including books and electronic databases, such as SCI finder, PubMed, Web of Science, ACS, Science Direct, Wiley, Springer, Taylor, J-STAGE and Google Scholar. Search was conducted covering the period from January 2013 to December 2018. RESULTS: In the in vitro studies diverse methods were used to test the essential oils activity, namely broth microdilution method, which resulted the most used one, followed by agar disk diffusion and vapour phase methods. Essential oils obtained by steam distillation were from different plant genera, Thymus, Artemisia, Malaleuca, Cinnamomun, Ocimum, Zataria, Rosmarinus, Origanum, Syzigium, Foenicolum, Thapsia, Tachyspermum, Myrtus. MIC values were expressed as µg/mL, µL/mL and by inhibition zone (mm) or µL/cm3. All the investigated essential oils were active at the tested conditions. In addition, two clinical studies used essential oils from Cymbopogon citratus and C. flexuosus formulated in shampoo, cream or lotion for the successful treatment of dandruff and P. versicolor. CONCLUSIONS: Results of these studies indicate worthy prospects for clinical application of essential oils and there is an urgent need to conduct further in vivo studies with large number of patients in order to verify the clinical potential of essential oils against Malassezia species.

Interactions between Clotrimazole and selected essential oils against Malassezia pachydermatis clinical isolates.

The aim of this study was to investigate interactions between conventional antifungal drug and essential oils against isolates of Malassezia pachydermatis. Antifungal activity of Cinnamomum cassia, Melaleuca alternifolia, Mentha piperita, Origanum vulgare and Syzygium aromaticum essential oils were tested against 19 strains of M. pachydermatis isolated from healthy dogs and reference strain M. pachydermatis CBS 1879. The checkerboard assay was used to search for in- teractions. Synergism was observed for the combination of clotrimazole with Melaleuca alternifolia essential oil, Mentha piperita and Origanum vulgare. The combinations of Cinnamomum cassia and Syzygium aromaticum essential oils with clotrimazole showed indifferent effect. Additive antimicrobial activity was observed for the combination of clotrimazole with Syzygium aromaticum and Melaleuca alternifolia essential oils against reference strain. The obtained results showed synergistic interactions between essential oils and clotrimazole which could improve effectiveness of this antifungal drug.

Multi-azole-resistant strain of Malassezia pachydermatis isolated from a canine Malassezia dermatitis.

In the case presented here, we describe the isolation of an azole-resistant strain of M. pachydermatis from a canine Malassezia dermatitis. The isolate (NUBS18001) from this case exhibited a minimum inhibitory concentration (MIC) of 320 µg/ml to itraconazole (ITZ) by broth microdilution (BM) assay, >32 µg/ml to ITZ by E-test, and >32 µg/ml to KTZ by E-test. Synergistic effects between FK506 and ITZ in the azole-resistant strain was evaluated using the microdilution checker-board method. The ITZ-resistant strain exhibited MICs of 320 µg/mL of ITZ alone and 5 µg/ml of FK506 alone; the addition of FK506 attenuated the ITZ MIC to 2.5 µg/ml, yielding an ITZ FICI value of 0.507. This result suggested that the combination of ITZ and FK506 exerted an additive effect against the ITZ-resistant strain. To understand the other mechanism inferred to be present in our multi-azole-resistant strain, we sequenced the ERG11 gene from this isolate, and detected missense mutations (A412G and C905T) in the sequence of the ERG11 open reading frame (ORF). To the best of our knowledge, this work is the first report that a multi-azole-resistant M. pacydermatis strain contains mutations in ERG11.

In vitro antimicrobial activity of seven adjuvants against common pathogens associated with canine otitis externa.

BACKGROUND: An antibiotic adjuvant is a chemical substance used to modify or augment the effectiveness of primary antimicrobial agents against drug-resistant micro-organisms. Its use provides an alternative approach to address the global issue of antimicrobial resistance and enhance antimicrobial stewardship. HYPOTHESIS/OBJECTIVES: To determine the antimicrobial activity of a panel of potential antimicrobial adjuvants against common pathogens associated with canine otitis externa (OE). ANIMALS/ISOLATES: A number of type strains and clinical isolates (n = 110) from canine OE were tested including Staphylococcus pseudintermedius, ß-haemolytic Streptococcus spp., Pseudomonas aeruginosa, Proteus mirabilis and Malassezia pachydermatis. METHODS AND MATERIALS: Antimicrobial activities of monolaurin, monocaprin, N-acetylcysteine (NAC), polymyxin B nonapeptide, Tris-EDTA, Tris-HCL and disodium EDTA were tested using microdilution methodology according to CLSI guidelines. RESULTS: N-acetylcysteine, Tris-EDTA and disodium EDTA had antimicrobial activity against both type strains and otic pathogens. The other adjuvants tested had limited to no efficacy. NAC had a minimal inhibitory concentration (MIC) range of 2,500-10,000 µg/mL for the various organisms. Pseudomonas aeruginosa isolates were eight times more susceptible to disodium EDTA in the presence of Tris-HCL in comparison to disodium EDTA alone. Malassezia pachydermatis isolates were most susceptible to Tris-EDTA (MIC90  = 190/60 µg/mL) and disodium EDTA (MIC90  = 120 µg/mL). CONCLUSIONS AND CLINICAL RELEVANCE: N-acetylcysteine, Tris-EDTA and disodium EDTA have intrinsic antimicrobial activity and represent promising adjuvants that could be used to enhance the efficacy of existing antibiotics against Gram-negative and multidrug-resistant bacterial infections. These agents could be combined with other antimicrobial agents in a multimodal approach for mixed ear infections in dogs.

Oxythiamine improves antifungal activity of ketoconazole evaluated in canine Malassezia pachydermatis strains.

BACKGROUND: Malassezia pachydermatis is an opportunistic yeast involved in skin and ear canal infections of dogs and cats. Reports suggest that strains of M. pachydermatis resistant to commonly used antifungal agents may be emerging. Therefore, new therapeutic strategies should be explored. OBJECTIVES: The synergistic effect of oxythiamine (OT) and ketoconazole (KTC) was analysed using a reference strain and field isolates (n = 66) of M. pachydermatis. Hydrogel formulations containing these components also were evaluated. METHODS AND MATERIALS: The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of OT, KTC and their mixtures were determined by a broth macrodilution method. The antifungal effects of hydrogel formulations were determined by a plate diffusion method. RESULTS: The MIC and MFC values of OT were in the range 0.08 × 103 to 10 × 103  mg/L. All M. pachydermatis strains showed higher susceptibility to KTC (MICs and MFCs in the range 0.04-0.32 mg/L). Formulations that combined OT and KTC showed a synergistic effect for all tested isolates (n = 66). Hydrogels that contained OT at a concentration of 10 × 103 or 20 × 103  mg/L and KTC at the concentration of 0.1 × 103  mg/L showed a stronger effect than a commercially available product with KTC alone (20 × 103  mg/L). CONCLUSIONS AND CLINICAL IMPORTANCE: Synergy of these drugs may allow for successful topical treatment which utilizes lower doses of KTC without changing its therapeutic effectiveness. Hydrogel formulations proved to be attractive drug carriers for potential topical use.

Malassezia ecology, pathophysiology, and treatment.

Malassezia are lipid dependent basidiomycetous yeasts that inhabit the skin and mucosa of humans and other warm-blooded animals, and are a major component of the skin microbiome. They occur as skin commensals, but are also associated with various skin disorders and bloodstream infections. The genus currently comprises 17 species and has recently been assigned its own class, Malasseziomycetes. Importantly, multiple Malassezia species and/or genotypes may cause unique or similar pathologies and vary in their antifungal susceptibility. In addition to culture-based approaches, culture-independent methods have added to our understanding of Malassezia presence and abundance and their relationship to pathogenicity. Moreover, these novel approaches have suggested a much wider-spread presence, including other human body parts and even other ecosystems, but their role in these arenas requires further clarification. With recent successful transformation and genetic engineering of Malassezia, the role of specific genes in pathogenesis can now be studied. We suggest that characterizing the metabolic impact of Malassezia communities rather than species identification is key in elucidation of pathophysiological associations. Finally, the increasing availability of genome sequences may provide key information aiding faster diagnostics, and understanding of the biochemical mechanisms for Malassezia skin adaptation and the design of future drugs.

In vitro efficacy of a honey-based gel against canine clinical isolates of Staphylococcus pseudintermedius and Malassezia pachydermatis.

BACKGROUND: Staphylococcus pseudintermedius and Malassezia pachydermatis are important agents in canine pyoderma and otitis. HYPOTHESIS/OBJECTIVES: Determine the in vitro efficacy of a honey-based gel (HBO) against meticillin-susceptible S. pseudintermedius (MSSP), meticillin-resistant S. pseudintermedius (MRSP) and M. pachydermatis, by minimum bactericidal concentration (MBC), minimum fungicidal concentration (MFC) and time-kill assay (TKA). Efficacy of the product's honey component (HO) also was evaluated. METHODS: Sixty S. pseudintermedius and 10 M. pachydermatis canine isolates were selected. All isolates were tested against serial dilutions of an HBO containing 40% HO (40%, 20%, 10%, 5% and 2.5% w/v) and HO alone (undiluted, 40%, 20%, 10%, 5% and 2.5% w/v). Microbroth assay followed by subculture was used to determine MBC and MFC. The same protocol was applied after product exposure to catalase. A well-diffusion assay for S. pseudintermedius was used to generate inhibition zones. A TKA for 10 isolates of S. pseudintermedius and 10 isolates of M. pachydermatis was performed. RESULTS: MBC was 20% w/v (5-20% w/v) for HBO and HO. HBO had lower MBC values when compared to HO (P = 0.003). No statistical difference was observed between MSSP/MRSP isolates (HBO P = 0.757, HO P = 0.743). Only HO was affected by catalase (P = 0.015). MFC for HBO was 10% w/v (5-10% w/v) and 40% w/v for HO (20-≥40% w/v). All isolates were killed after 4 h of exposure. CONCLUSIONS AND CLINICAL IMPORTANCE: Staphylococcus pseudintermedius and M. pachydermatis are susceptible to the HBO and these results can be used for future clinical trials.

Blad-containing oligomer: a novel fungicide used in crop protection as an alternative treatment for tinea pedis and tinea versicolor.

PURPOSE: The lack of novel antifungal drugs and the increasing incidence and severity of fungal infections are major concerns worldwide. Herein, we tested the activity of the Blad-containing oligomer (BCO), a new antifungal molecule already in use for agriculture, on Malassezia spp. and dermatophytes, the causal agents of human tinea versicolor and tinea pedis. Given the lack of a standard method for Malassezia susceptibility testing and the plethora of published methods, we also developed an improved method for this genus. METHODOLOGY: The efficacy of BCO was assessed in vitro and compared to that of the drugs currently utilized in the treatment of tinea versicolor (fluconazole and itraconazole) and tinea pedis (itraconazole and terbinafine). For dermatophytes, the standard microdilution broth-based method was used, with small adjustments, and several broth formulations and inocula sizes were tested to develop an improved susceptibility method for Malassezia spp. RESULTS: We successfully developed a microdilution broth-based method with considerable advantages over other available methods, and used it for all in vitro susceptibility tests of Malassezia spp. isolates. We report that, on a molar basis, BCO was more effective than fluconazole or itraconazole on most strains of Malassezia spp. isolated from clinical samples (n=29). By contrast, BCO was less effective than itraconazole or terbinafine on the common dermatophytes Trichophyton rubrum and Trichophyton interdigitale. CONCLUSION: These data place BCO as a promising drug for the treatment of Malassezia-associated skin diseases. Further in vivo studies are now required to ascertain its applicability in the clinical setting.

Liquid and Vapor-Phase Activity of Artemisia annua Essential Oil against Pathogenic Malassezia spp.

Artemisia annua essential oil has given us many encouraging results for its numerous antimicrobial properties. In this study, the essential oil, both in liquid and in vapor phases, was tested against various Malassezia species closely related to many skin disorders in humans and animals. Malassezia treatment and eradication are mainly based on old azole drugs, which are characterized by poor compliance, unpredictable clinical efficacy, emerging resistance, and several side effects. Monoterpenes (ca. 88%) represent the most abundant group of compounds in the essential oil, mainly the oxygenated derivatives (ca. 74%) with camphor (25.2%), 1,8-cineole (20%), and artemisia ketone (12.5%). In vapor phase, monoterpenes represent more than 98% of the constituents, α-pinene being the main constituent (22.8%), followed by 1,8-cineole (22.1%) and camphene (12.9%). Essential oil of A. annua, both in vapor phase and liquid, showed strong antimicrobial activity towards almost the tested twenty strains of Malassezia analyzed. The minimum fungicidal concentrations from most of the strains tested were from 0.78 µL/mL to 1.56 µL/mL, and only three strains of Malassezia sympodialis required a higher concentration of 3.125 µL/mL. Overall, the minimal inhibitor concentrations obtained by vapor diffusion assay were lower than those obtained by the liquid method. The average values of minimal inhibitor concentrations obtained by the two methods at 72 h are 1.3 - 8.0 times higher in liquid compared to those in the vapor phase.

Antifungal activity of Myrtus communis against Malassezia sp. isolated from the skin of patients with pityriasis versicolor.

The increasing incidence of fungal infections and antifungal resistance has prompted the search for novel antifungal drugs and alternative agents. We explored the antifungal activity of Myrtus communis essential oil (EO) against Malassezia sp. isolated from the skin of patients with pityriasis versicolor. These broad-spectrum antimicrobial activities of M. communis EO and its potent inhibiting activity on Malassezia growth deserve further research with aim to considerate this EO as candidate for topical use in treatment of skin diseases.

Evaluation of selected Indian medicinal plants for antagonistic potential against Malassezia spp. and the synergistic effect of embelin in combination with ketoconazole.

The genus Malassezia comprises of extremely lipophilic yeasts secreting lipases as a vital factor for survival. They are emerging as opportunistic pathogens in medical microbiology and dermatology by causing recurring and recalcitrant infection. Combinatorial therapy is a constructive way to combat infectious diseases. In that prospect, totally 16 Indian medicinal plants were screened, among which a maximum degree of antimicrobial activity was ascertained in Embelia ribes. Subsequently embelin was identified as the bioactive principle with antagonistic potential by comparative antimicrobial assay and FTIR analysis. The MIC of embelin was determined as 400 µg/ml exhibiting ∼75% of growth inhibition. Further, a fungistatic activity based on anti-lipase potential (65-89%) of embelin has been clearly substantiated by XTT and lipase assay. In addition, embelin exhibited a synergistic effect with the antifungal drug ketoconazole (KTZ) against four different Malassezia spp. with FIC index of 0.5. Therefore, the combinations of embelin and KTZ may represent a promising therapeutic regimen to treat Malassezia infections with subjugated clinical and environmental toxicity. To the best of our knowledge, this is the first report delineating the anti-lipase activity of embelin and in vitro synergistic interaction between embelin and KTZ against Malassezia spp.

New targets in the battle against dandruff.

Dandruff is a scalp disorder characterized by flaking skin and itch of an excessive oily scalp skin. It affects 55% of the global youth and adult population. Seborrheic dermatitis is a similar scalp skin disorder with aggravated itchy rashes and flaking. Different factors are identified in the dandruff development: increased sebum production, uncontrolled fungal growth of Malassezia strains and individual reaction to pro-inflammatory environment, and the susceptibility to trigger an immunological response. Using in vitro and ex vivo models, we show that an Epilobium angustifolium extract dose dependently reduces lipid synthesis in sebocytes to a maximum of -43% (1% extract), and protects the epidermis from Malassezia-induced morphological changes. Epilobium angustifolium extract also acts through innovative mechanisms involving regulations of defensins (human beta-defensins [hBD2] and hBD3) and toll-like receptor 2 involved in the immunological response of the skin. The anti-dandruff and sebum-regulating efficacy of E. angustifolium extract (1.5%) was confirmed in a clinical study that mobilized 24 volunteers with dandruff and greasy scalp for 30 days. At the end of the study, nonadherent and adherent dandruffs were significantly (p < 0.0001) reduced in average by -54% and -48%, respectively. Using Sebumeter® measurements, scalp sebum production was inhibited by -67% (p < 0.0001) in average over baseline. In conclusion, E. angustifolium extract offers a new innovative approach to dandruff reduction through immunomodulation of the skin response to Malassezia invasion.

Traditional Mediterranean plants: characterization and use of an essential oils mixture to treat Malassezia otitis externa in atopic dogs.

Several plants extracts from Mediterranean countries are traditionally employed in skin troubles both in humans and in animals. Malassezia pachydermatis is a lipophylic yeast responsible for otitis externa and dermatitis in dogs and for cutaneous and systemic disease in humans. Five mixtures of essential oils obtained from Mediterranean plants (Citrus paradisi, Salvia sclarea, Ocimum basilicum, Rosmarinus officinalis, Citrus limon, Anthemis nobilis, Lavandula hybrida and Thymus vulgaris) provided with antifungal and/or anti-inflammatory action assayed in vitro, were tested in vivo versus M. pachydermatis to treat once daily for 2 weeks 25 atopic dogs with Malassezia otitis externa. Mixture composed by C. limon 1%, S. sclarea 0,5%, R. officinalis 1%, A. nobilis 0,5% yielded excellent results in all treated dogs. Despite of clinical resolution after all treatments the number of blastospores did not decrease. This study confirms recent findings suggesting a multifactorial alternative approach for the management of canine Malassezia otitis.