Prevalence of Malassezia species in pityriasis versicolor lesions in northeast Argentina

Background: Malassezia species normally colonize the skin but they can change their saprophytic state and invade the stratum corneum as pathogens. Aims: To determine the prevalence of Malassezia species isolated from patients with pityriasis versicolor (PV) and to analyse their distribution according to the location of the lesion on the body. Methods: This study included 218 patients with PV and positive Malassezia cultures who resided in the city of Resistencia, a subtropical area located in northeast Argentina. Age, gender, and the body site of lesions were recorded. Strains were identified by PCR-RFLP. Results: Malassezia sympodialis (37.7%) and Malassezia globosa (37.2%) were the most prevalent species isolated alone or in association with other Malassezia species in 82% of the patients. Malassezia furfur (21.3%) was the third most common species, followed by Malassezia slooffiae (1.7%), and Malassezia restricta (1.3%), which was found only in combination with M. globosa and M. sympodialis. Malassezia dermatis (0.4%) and Malassezia pachydermatis (0.4%) were each isolated once. None of the species affected a body site with statistical significance. Significant difference between genders according to age was found only in the 31-40-year-age group. Conclusions: This study suggests that M. sympodialis and M. globosa represent the main species implicated in the pathogenicity of PV. M. furfur appears to be the third agent of importance in this geographical area. Statistical analyses showed none of the species was particularly associated with any one of the body sites.Original Abstract: Antecedentes: Las especies de Malassezia colonizan normalmente la piel, pero ante deltas condiciones pueden cambiar su estado saprofitico y transformarse en patogenas. Objetivos: Estudiar la prevalencia de especies de Malassezia aisladas de pacientes con pitiriasis versicolor (PV) y su distribucion de acuerdo al sitio anatomico de las lesiones. Metodos: Este trabajo se realizo en la ciudad de Resistencia, ubicada en una region subtropical del nordeste de la Argentina. Se incluyeron 218 pacientes con PV y cultivo positivo para Malassezia. Edad, genero y sitios anatomicos de las lesiones fueron registrados. Las cepas fueron identificadas por PCR-RFLP. Resultados: Malassezia sympodialis (37,7%) y Malassezia globosa (37,2%) fueron las especies con mayor prevalencia, aisladas en el 82% de los pacientes, bien como agente unico o en asociacion con otras especies. Malassezia furfur (2