Análisis cuantitativo de las especies del género "Malassezia" como microbiota cutánea de piel sana de individuos con diferentes características demográficas y de estados de salud

Abstract

The yeasts of Malassezia genus are part of the regular skin of men and other vertebrates. The recent description of new species for the genus has brought interest on their study throughout diverse countries; thus, it’s important to carry out research towards obtaining epidemiological data of Malassezia species in tropical regions like Venezuela. The goal of the present study is to characterize the species of the Malassezia genus isolated from healthy skin of individuals belonging to different age and sex groups, habitats and health status. This study was performed on healthy skin from 587 people, distributed as follows: 98 newborns (24 hours after birth), 80 children (0 – 6 years), 100 adolescents (12 – 18 years), 56 young adults (19 – 25 years), 100 elderly (60 – 89 years), 25 indigenous children from the Añú ethnic group (0 – 6 years), and 80 children with AIDS (0 – 6 years). Samples were taken using the imprinting with transparent tape, from areas like the scalp, ear pavilion, chest and back, and then inoculated in modified Dixon and Sabouraud Dextrose agar media and incubated at 32 C for 14 days. Identification of species was performed following the guidelines described by Guého et al, the difussion in Tween test proposed by Gullot et al, the catalase test, and the use of triptofane as the only source of nitrogen. It was evident that in the elderly population, 82 (82.0 %) and in the adolescent population, 80 (80.0 %) were reported as the highest number of individuals positive to Malassezia spp (p<0.05). A significant difference was obtained between genders regarding the number of individuals positive to the Malassezia spp., male 118 (57.3 %) positive individuals, and female 88 (42.7 %). It was assessed that among the healthy individuals population, M. furfur was the predominantly significant species with 158 (58.7%) isolated, followed by M. sympodialis 71 (26.4%), M. globosa 25 (9.3%) and M. slooffiae 15 (5.6%). When assessing the isolation of Malassezia spp.in the different anatomical locations studied, it was observed that in the back, the highest number of isolations was observed, 118 (27.5 %) without statistical significance, also ear pavilion 116 (27.0 %), chest 113 (26.3 %) and scalp 82 (19.1 %). From the 25 Añú children studied, 19 were significantly positive to Malassezia spp. M. furfur (82.6 %) was the predominant species (p<0.05), followed by M. sympodialis (19.4 %). The anatomical location with the highest number of isolations for the Añú children was the ear pavilion (30.9 %). 66,7 % of the undernourished children studied were significantly positive to Malassezia spp. M. furfur (91.4 %) was the most isolated species (p<0.05 %). Important differences were observed among the undernourished children and the healthy children. 21 children with AIDS were isolated Malassezia spp. The only isolated species was M. sympodialis. No significant results were obtained when comparing the population of children with AIDS to the population of healthy children.