Identification of Malassezia species isolated from patients with extensive forms of pityriasis versicolor in Siena, Italy

Características clínico-epidemiológicas de los pacientes con pitiriasis versicolor en un centro de referencia de Colombia

Objetivo: describir las características socio-demográficas, presentación clínica y condiciones extrínsecas que pueden favorecer el desarrollo de la pitiriasis versicolor. Material y métodos: estudio observacional descriptivo, de corte transversal y prospectivo, en el que se incluyeron pacientes con diagnóstico clínico y micológico de pitiriasis versicolor entre enero y diciembre de 2018, que asistieron al Hospital Universitario Centro Dermatológico Federico Lleras Acosta. Resultados: se incluyeron un total de 42 pacientes con diagnóstico de pitiriasis versicolor confirmado por examen directo, el 62% fueron hombres con una edad promedio de 33 años. La localización más común fue el tórax anterior (68%) y posterior (65%), en fototipos III y IV (78.5%), con una tonalidad hipocrómica. El 28% presentaron cuadros recurrentes, con síntomas hasta 7 años antes de la consulta. El signo de Besnier fue positivo en el 95% de los casos. El 64% refirió antecedente personal de hiperhidrosis y el 67% practicaba algún deporte como buceo, natación o gimnasia. Discusión: la identificación de las condiciones extrínsecas presentes esta población permite orientar medidas de prevención para evitar recurrencias de pitiriasis versicolor. Los viajes a lugares de clima cálido y la práctica de deportes son factores que favorecen el desarrollo de la micosis. En las formas clínicas atípicas se sugiere realizar siempre el examen micológico directo para confirmar el diagnóstico. El signo de Besnier es una maniobra útil para el diagnóstico clínico de la pitiriasis versicolor, particularmente cuando el acceso al examen directo es limitado.

Molecular epidemiology, in vitro susceptibility and exoenzyme screening of Malassezia clinical isolates

Introduction. Malassezia folliculitis (MF) and pityriasis versicolor (PV) are common dermatoses caused by Malassezia species. Their molecular epidemiology, drug susceptibility and exoenzymes are rarely reported in China.Aim. To investigate the molecular epidemiology, drug susceptibility and enzymatic profile of Malassezia clinical isolates.Methodology. Malassezia strains were recovered from MF and PV patients and healthy subjects (HS) and identified by sequencing analysis. The minimum inhibitory concentrations (MICs) of nine antifungals (posaconazole, voriconazole, itraconazole, fluconazole, ketoconazole, miconazole, bifonazole, terbinafine and caspofungin) and tacrolimus, the interactions between three antifungals (itraconazole, ketoconazole and terbinafine) and tacrolimus, and the extracellular enzyme profile were evaluated using broth and checkerboard microdilution and the Api-Zym system, respectively.Results. Among 392 Malassezia isolates from 729 subjects (289 MF, 218 PV and 222 HS), Malassezia furfur and Malassezia globosa accounted for 67.86 and 18.88 %, respectively. M. furfur was the major species in MF and PV patients and HS. Among 60M. furfur and 50M. globosa strains, the MICs for itraconazole, posaconazole, voriconazole and ketoconazole were <1 μg ml^-1. M. furfur was more susceptible to itraconazole, terbinafine and bifonazole but tolerant to miconazole compared with M. globosa (P<0.05). Synergistic effects between terbinafine and itraconazole or between tacrolimus and itraconazole, ketoconazole or terbinafine occurred in 6, 7, 6 and 9 out of 37 strains, respectively. Phosphatases, lipases and proteases were mainly secreted in 51 isolates.Conclusions. Itraconazole, posaconazole, voriconazole and ketoconazole are theagents against which there is greatest susceptibility. Synergistic effects between terbinafine and itraconazole or tacrolimas and antifungals may be irrelevant to clinical application. Overproduction of lipases could enhance the skin inhabitation of M. furfur.

MALDI-TOF MS identification of Malassezia species isolated from patients with pityriasis versicolor at the seafarers' medical service in Dakar, Senegal

Pityriasis versicolor (PV) is a superficial mycosis caused by yeast of the genus Malassezia. The most common isolated Malassezia species in PV lesions differ among M. furfur, M. globosa and M. sympodialis. We purpose to determine the distribution of Malassezia species in PV patients at the seafarers' medical service in Dakar, Senegal and to examine whether any association between identified Malassezia species and patients' profile. From May 2017 to August 2017, first a questionnaire was filled to get informative data before collection of skin scrapings taken from most scaly site using sterile scalpel blade and application of scotch^® for direct examination (DE). At the laboratory, DE, culture and identification by MALDI-TOF MS were done. One hundred patients with PV - all men - were included with a mean age of 34 years. Among seafarers, 81% were sailors. Clinical prevalence of PV was highest in aged adults patients with ages of 31 to 60 years (56%). Seafarers with high level of education were less representative with only 2%. The mean duration of the PV was 26.83 months. 20% of subjects suffered lesions in more than one location. The chest was the most affected anatomical site. Furthermore, possible predisposing factors associated with PV were also detected. DE was positive in 95% but culture growth only in 46%. MALDI-TOF MS analysis of the positive cultures could be performed in 84.8% (39/46). Only M. furfur was identified in 100% (39/39). In definitive, M. furfur is the only causative agent of PV in Dakar.

Recurrent and disseminated pityriasis versicolor: A novel clinical form consequent to Malassezia-host interaction?

Pityriasis versicolor is a superficial fungal infection caused by Malassezia spp. The aim of this study is to propose the definition of a new clinical entity: the recurrent and disseminated pityriasis versicolor (RDPV). All patients with RDPV were enrolled over an eight-month period. Clinical and epidemiological data were obtained, Malassezia (M.) species were isolated in cultures and identified by phenotypic and molecular characterization, skin biopsies were taken from active lesions, serum levels of immunoglobulin E were obtained and therapeutic schemes were evaluated. A total of 16 patients were included (11 male, 5 female). The most frequently isolated species were M. japonica (n = 3) and M. furfur (n = 3). This is the first study that isolates M. japonica in patients with pityriasis versicolor; interestingly, those were recalcitrant patients. Seven patients (43.8%) had no cure with any of the proposed treatments; among those, 5 (71.4%) had increased serum IgE levels. The most effective treatment was itraconazole 200 mg daily for 28 days. The RDPV has very different features from the classic form, including a poor response to treatment, and the isolation of different Malassezia species; therefore, we propose a hypothesis for the definition of a new clinical condition (RDPV), which could be a result of the interaction Malassezia-host.

Molecular and Phenotypic Identification and Speciation of Malassezia Yeasts Isolated from Egyptian Patients with Pityriasis Versicolor

INTRODUCTION

Pityriasis Versicolor (PV) is a common health problem caused by genus Malassezia, a lipophilic fungi found as a part of the normal flora of skin. Although PV is common in Egypt, there is little information regarding the Malassezia species distribution in PV patients to date.

AIM

To spot a light on the distribution and clinico-epidemiological features of the Malassezia species in PV patients and healthy individuals that were established by conventional phenotypic and molecular techniques.

MATERIALS AND METHODS

A cross-sectional study including 167 individuals; 137 clinically suspected PV patients attending Mansoura University Hospitals, Egypt and 30 healthy control individuals, was carried out. Characterization of Malassezia species was performed phenotypically by conventional, culture-based methods and biochemical tests. Genomic DNA was extracted from isolated colonies for PCR amplification of the highly conserved 26S rDNA region with further species level identification by Restriction Fragment Length Polymorphism (RFLP) using Hha1 and BstC1 enzymes. The association of Malassezia species with epidemiological profile and clinical characteristics was studied.

RESULTS

A 94.2% of PV samples and 13.3% of control samples were positive by Potassium Hydroxide (KOH) while 71.5% of PV samples and 16.7% of control samples yielded growth in culture with high statistically significant differences (p=0.0001, for both methods). By phenotypic methods, only 75.5% of isolates from patients were identified as: M. furfur (51.4%), M. globosa, (29.7%), M. restricta (13.5%) and M. pachydermatis (5.4%) while by RFLP technique, six species were revealed: M. furfur (44.9%), M. globosa (24.5%), M. sympodialis (12.2 %), M. restricta (10.2%), M. obtusa (4.1%) and M. pachydermatis (4.1%). Most species were isolated from hypopigmented lesions of PV patients aged between 20-29 years. Neck and back were the most common affected sites. Only M. furfur (10%) and M. globosa (6.7%) were identified in healthy controls.

CONCLUSION

M. furfur and M. globosa are the commonly encountered species in both healthy and diseased human skin although other species were identified in PV patients. PCR-RFLP method represents a considerably accurate technique in identification of different Malassezia species for better understanding of their effect on the clinico-epidemiological characterization of PV patients in Egypt.

The spectrum of Malassezia species isolated from students with pityriasis vesicolor in Nigeria

Pityriasis versicolor (PV) is a common superficial fungal infection of the skin caused by Malassezia. Initially M. furfur was suggested as its main aetiological agent; however, more recent studies suggest M. globosa as the dominant species. The possibility of a variance in predominant species based on geographical basis has not been fully evaluated. The objective of this study was to identify the Malassezia species on affected and non-affected skin of students with PV who reside in a tropical environment (Abuja, Nigeria) and correlate them to clinical characteristics. In this study, the literature on prevalence of Malassezia genus in PV was also reviewed. Samples were taken from 304 PV lesions and 110 normal appearing skin. Microscopy, culture and identification of Malassezia species utilising polymerase chain reaction-restriction fragment length polymorphism analysis were performed. Three Malassezia species were detected in PV with the major species being M. furfur. On normal appearing skin, M. furfur (77.6%) and M. restricta (10.4%) were both detected. No case of M. globosa was identified in this study. There was no significant difference between species identified and clinical features of PV. M. furfur is probably still the most predominant species causing PV in the tropical environment.