Isolation of Malassezia spp. colonies on skin swabs in two types of agars in a pediatric institute in Lima - Peru, in 2022

Abstract

Objective: To determine the isolation capacity and number of colonies of Malassezia spp. by using skin swabs applying a conventional agar and a modified one at the Instituto Nacional de Salud del Niño in Breña (Lima) in 2022. Materials and methods: Descriptive observational study that compared a (conventional) Leeming & Notman agar with olive oil and an (proposed) agar modified with coconut oil. 180 skin swabs collected during March-November 2022 were cultured. The culture media were monitored for seven days, and all the information was recorded in a data collection form and compared with the U-Mann Whitney test. Results: The characteristics of the skin lesions from which the swabs were taken were mostly whitish (38.9 %). Fungal isolation capacity in both agars was the same, with Malassezia furfur being predominant (23.3 %). However, the median of the isolated fungal colonies was significantly higher (p = 0.025) in the agar modified with coconut oil. Conclusions: Mild lesions such as whitish areas on the skin with a median of 2 cm² predominated. There were no differences in terms of isolation capacity; however, a greater number of colonies developed on the agar supplemented with coconut oil, proving to be a better lipid source than olive oil.