Malassezia Species Associated Seborrheic Dermatitis and Its Comparison between HIV Positive and Negative Patients

Introduction: Malassezia yeasts are lipophilic organisms causing certain skin diseases. Seborrheic dermatitis (SD) is the second most common skin infection caused by Malassezia as well as in HIV/AIDS. Aim: To determine the frequency of association of Malassezia species in HIV infected and HIV non-infected patients with Seborrheic dermatitis. Materials and Methods: The prevalence of Seborrheic dermatitis is 5% in the general population. Hence a sample size of 80 was derived, 40 each of HIV seropositive and HIV seronegative adult patients clinically suspected of having Seborrheic Dermatitis. Specimens were collected by scraping and cellophane tape for KOH and Chicago Sky Blue (CSB) stain, and were cultured on Sabouraud’s dextrose agar. Data were analysed using SPSS version 16.0. P ≤ 0.05 was considered as significant. Results: Majority of the patients i.e. 46 (57.5%) out of 80 were in the age group of 18-30 years with male preponderance. All HIV positive patients with SD had scaly, greasy, itchy, hypo-pigmented and erythematous lesions, & neck (23) and groin (20) were commonest sites. In 39 HIV positive and 22 HIV negative patients, >2 sites were involved. Majority of the HIV negative patients with SD had scaly (40), itchy (24) and hypo-pigmented lesions (27) & dandruff, and scalp (24) & neck (18) were commonest sites. (P<0.05). Twenty HIV positive patients had CD4 count ranging from 200-350 cells/mm3. Malassezia was detected in 38 and 34 HIV positive & negative patients respectively in laboratory diagnosis. Conclusion: Seborrheic Dermatitis has severe presentation at multiple sites in HIV positive patients as compared to HIV negative patients. Key words: Malassezia, Seborrheic dermatitis, HIV positive, HIV negative.

Production and Quantification of Virulence Factors in Malassezia Species

A total of 77 strains of Malassezia were included in this study. Biofilm production and hydrolytic enzymes were studied by using specific solid media. Real-time Reverse Transcriptase qPCR method was applied to determine overexpression of genes encoding extracellular enzyme. All included Malassezia species produced biofilms. No statistical significant difference was observed between biofilm formation of the Malassezia species (P = 0.567) . All Malassezia species produced lipase and 95% of M. globosa showed a strong enzymatic activity (Pz=0.55 ± 0.02). Statistical significant difference was observed between the mean keratinase indices of M. slooffiae and the others Malassezia species ( P = 0.005). The overexpression of one or more genes was observed in 100% of strains isolated from patients with folliculitis, in 87.5% for pityriasis versicolor isolates and in 57.14% for the control group isolates. A statistical significant difference of the lipase gene expression ( P = 0.072) was associated with the strains collected from patients with folliculitis vs group control. This investigation provides more information about the frequency of the production of the major enzymes considered to be virulence factors of Malassezia species. Interestingly, the overexpression of one or more genes was observed in strains isolated from patients with Malassezia disorder.

Identification of Malassezia Species Isolated from Pityriasis Versicolor by CHROMagar-Medium

Background Pityriasis versicolor is a chronic superficial fungal infection seen worldwide, with high prevalence observed in hot and humid climates. Objectives The aim of this work was to isolate and identify Malassezia species from pityriasis versicolor using specific fast gtowth media; Chrom agar to obtain a better understanding of the role of each species in the etiology of disease. Patients and Methods This study was conducted on 70 patients with clinical diagnosis of pityriasis versicolor with positive KOH test. All of the participants were subjected to a well informed consents, full history taking including age, sex, site of the lesions and any previous treatment, full general and dermatological examination to determine site, color of the lesions and Wood's light examination. Results Our results reported 94.3% of studied patients yielded growth on culture while 5.7% did not show any growth. The predominant age group was ≥ 25 years old. Furthermore it was found that PV affected male subjects (62.90%) more than the females (37.1%). Conclusion Malassezia yeasts, although are considered a part of normal skin microbiome, is a known cause of pityriasis versicolor. PV was more common in males in the age group ≥ 25yrs. The most affected body site was the chest, the most common variant is hyperpigmented type, and the commonest isolate was M.furfur.

MalaSelect: A Selective Culture Medium for Malassezia Species

Malassezia species are fastidious and slow-growing yeasts in which isolation from polymicrobial samples is hampered by fast-growing microorganisms. Malassezia selective culture media are needed. Although cycloheximide is often used, some fungi, including the chief human commensal Candida albicans, are resistant to this compound. This study aimed to test whether the macrolide rapamycin could be used in combination with cycloheximide to develop a Malassezia-selective culture medium. Rapamycin susceptibility testing was performed via microdilution assays in modified Dixon against two M. furfur and five Candida spp. The MIC was the lowest concentration that reduced growth by a minimum of 90%. Rapamycin ± cycloheximide 500 mg/L was also added to FastFung solid, and yeast suspensions were inoculated and incubated for 72 h. Rapamycin MICs for Candida spp. ranged from 0.5 to 2 mg/L, except for C. krusei, for which the MIC was > 32 mg/L. M. furfur stains were rapamycin-resistant. Rapamycin and cycloheximide supplementation of the FastFung medium effectively inhibited the growth of non-Malassezia yeast, including cycloheximide-resistant C. albicans and C. tropicalis. Based on our findings, this “MalaSelect” medium should be further evaluated on polymicrobial samples for Malassezia isolation and culture.

Identification of Malassezia Species in Seborrheic Dermatitis Patients by CHROM Agar-Medium

Background Seborrheic dermatitis (SD) is a subacute or chronic superficial inflammatory skin condition, characterized by pruritic, erythematous plaques with greasy, yellow-gray scales, which appear on areas rich in sebaceous glands such as the face, scalp, upper chest, and back. Aim of the Work To identify Malassezia species that are involved in the development of SD in different body sites (face, scalp and trunk) and in different age groups, by using Chrom agar. Patients and Methods Forty nine patients with seborrheic dermatitis attending dermatology outpatient clinic in Ain shams university hospital the samples collected from December 2018 to June 2019. Results In this study, the most affected areas were the scalp and other sites as face and ears, which is concordant with the majority of studies worldwide. The role of sex in propensity to the development of Malassezia spp. Infection in SD is still unclear. Conclusion The distribution of Malassezia spp. on healthy and diseased skin shows significant variation and differences, although our knowledge of Malassezia yeasts has increased tremendously during the last two decades, their pathological roles remain ambiguous, and there is currently no conclusive evidence that any given species is responsible for a specific disease.

Fungal Infections among Psoriatic Patients: Etiologic Agents, Comorbidities, and Vulnerable Population

Background. Psoriasis is a chronic inflammatory disorder of the skin and joint, affecting nearly 2-3% of the general population. It is assumed that imbalance between the types of natural microflora can accelerate the onset of the disease. Some fungi can play the role of superantigens and prolong chronic inflammation in the skin of psoriatic patients. The aim of the present investigation was to identify fungal species isolated from patients with psoriasis. Methods. From March 2016 to May 2019, 289 patients with prior diagnosis of psoriasis were included in this survey. Direct microscopy with potassium hydroxide (KOH 10%), culture, urea hydrolysis, hair perforation test, and growth on rice grains were used to identify clinical isolates, phenotypically. For molecular identification of Candida species and Malassezia species, PCR-RFLP and PCR-sequencing were used, respectively. Results. Forty-six out of 289 psoriatic patients had fungal infections (15.9%). Dermatophytes (54.3%), Candida spp. (19.5%), Malassezia spp. (15.2%), Aspergillus spp. (6.5%), and Fusarium spp. (4.3%) were the causative agents of fungal infections. Among Malassezia and Candida species, M. restricta (10.8%) and C. glabrata (8.7%) were the most prevalent species, respectively. Conclusion. Our findings suggested that fungal pathogens, particularly dermatophytes, may play an important role in the pathogenicity of psoriasis. Also, due to the high rate of yeast colonization in the clinical samples of psoriatic patients, concomitant use of anti-inflammatory drugs and antifungals may represent an effective therapeutic approach for better management of chronic lesions among these patients. Mycological tests should be applied to indicate the incidence of fungal diseases in psoriatic patients.

Targeted Delivery of Zinc Pyrithione to Skin Epithelia

Zinc pyrithione (ZnPT) is an anti-fungal drug delivered as a microparticle to skin epithelia. It is one of the most widely used ingredients worldwide in medicated shampoo for treating dandruff and seborrheic dermatitis (SD), a disorder with symptoms that include skin flaking, erythema and pruritus. SD is a multi-factorial disease driven by microbiol dysbiosis, primarily involving Malassezia yeast. Anti-fungal activity of ZnPT depends on the cutaneous availability of bioactive monomeric molecular species, occurring upon particle dissolution. The success of ZnPT as a topical therapeutic is underscored by the way it balances treatment efficacy with formulation safety. This review demonstrates how ZnPT achieves this balance, by integrating the current understanding of SD pathogenesis with an up-to-date analysis of ZnPT pharmacology, therapeutics and toxicology. ZnPT has anti-fungal activity with an average in vitro minimum inhibitory concentration of 10–15 ppm against the most abundant scalp skin Malassezia species (Malassezia globosa and Malassezia restrica). Efficacy is dependent on the targeted delivery of ZnPT to the skin sites where these yeasts reside, including the scalp surface and hair follicle infundibulum. Imaging and quantitative analysis tools have been fundamental for critically evaluating the therapeutic performance and safety of topical ZnPT formulations. Toxicologic investigations have focused on understanding the risk of local and systemic adverse effects following exposure from percutaneous penetration. Future research is expected to yield further advances in ZnPT formulations for SD and also include re-purposing towards a range of other dermatologic applications, which is likely to have significant clinical impact.

IDENTIFICATION OF MALASSEZIA SPECIES AND ITS ASSOCIATION WITH CLINICAL MANIFESTATIONS OF ATOPIC DERMATITIS

Introduction: Atopic dermatitis is a chronic, recurrent inflammatory skin disease that is characterized by an eczematous reaction. Few studies have investigated fungi in the pathogenesis of atopic dermatitis, however, there are different about distribution of Malassezia species. Objectives: To indentificate of Malassezia species and its asociation with clinical manifestations in Vietnamese atopic dermatitis patient. Methods: 178 patients who were diagnosed with atopic dermatitis and had a postitive direct examination of Malassezia at the National hospital of dermatology and venereology between July 2019 and June 2020. Specimens were taken with cellotape, then stained in 20% of potassium hydroxit combined with ParkerTM blue black ink. All patient who had postive test were cultured on SDA and mDixon. For fungal samples, we selected pure colonies with morphological characteristics of yeast as follows about 1cm in diameter, round, cream or milky in color, smooth and glossy to detect the species. Results: From the samples of atopic dermatitis patients, we cultured and idenfified 41 cases. 5 species were found, in which M. globosa was the most common species, accounting for 39%, followed by M. restricta (19.5%), M. dermatis (17.1%), M. furfur (17.1%) and M. sympodialis (2.4%). Conclusion: On the skin lesions of Vietnamese patients with atopic dermatitis, M. globosa was the most common species with 39.0%.

MalaSelect: a Selective Culture Medium for Malassezia Species Isolation

Malassezia species are fastidious and slow-growing yeasts whose isolation from polymicrobial samples is hampered by fast-growing microorganisms. Malassezia selective culture media are needed because Malassezia are resistant to cycloheximide, but some fungi, including the chief human commensal Candida albicans resist to this compound. This study aimed to test whether the macrolide rapamycin could be used in combination with cycloheximide to develop a Malassezia-selective culture medium. Rapamycin susceptibility testing was performed via microdilution assays in modified Dixon against M. furfur and five Candida spp. The MIC was the lowest concentration producing 90% growth inhibition. Rapamycin medium &plusmn; cycloheximide 500 mg/L was also added to FastFung solid and yeast suspensions were inoculated and incubated for 72h. Rapamycin MICs against Candida spp. ranged from 0.5 to 2 mg/L, except for C. krusei whose MIC was &amp;gt;32 mg/L. M. furfur stains were rapamycin resistant. Rapamycin and cycloheximide supplementation of the FastFung medium effectively inhibited the growth of non-Malassezia yeast, including the cycloheximide-resistant C. albicans and C. tropicalis. Based on our findings, we recommend using this &ldquo;MalaSelect&rdquo; medium for Malassezia isolation and culture from polymicrobial samples.