Morphological Study of Malassezia Species Isolated from Pityriasis Versicolor Patients in Thi-Qar Governorate and Their Sensitivity to Some Antifungal Drugs

Abstract

Background: Malassezia are lipophilic yeasts that coexist symbiotically on the skin of humans
and other warm-blooded animals. They assume two forms: unicellular yeasts and pseudofilamentous
yeasts. Malassezia yeasts are opportunistic and exhibit coexistence with their host without adverse
effects. However, they are capable of causing infection in humans under specific circumstances that
facilitate their growth, such as a compromised immune system and a pH change. Approximately 80%
of healthy individuals harbor Malassezia yeasts, which naturally colonize the epidermis of humans
around three months after birth.
The Pityriasis versicolor (PV) is induced by Malassezia yeast. The yeasts invade the outermost
keratinized layer of human skin and induce several alterations in this layer, such as the formation of
different-colored patches on the skin. The spots are scaly and can be classified into two types:
hypopigmentation, which refers to a condition where the spots are lighter than the skin tone, and
hyperpigmentation, which characterizes a condition where the spots are darker than the skin color,
resulting in red spots. This condition manifests on many regions of the skin, encompassing the arms,
upper body, neck, and face. Furthermore, it manifests on the hair, and it is rarely observed to impact
the nails. This infection may be asymptomatic or it is accompanied by mild pruritus.
Objective: This study aims to isolate and phenotypically identify Malassezia species from pityriasis
versicolor patients, as well as compare their prevalence in patients with that of healthy individuals.
Methods: About 72 skin scraping samples were collected from patients diagnosed by the
dermatologist as pityriasis versicolor patients and 30 skin swabs from healthy individuals at the period
from Jul-2023 to Dec-2023. All samples were tested for morphological identification and anti-fungal
sensitivity of Malassezia Spp.
Results: The study revealed that the prevalence of Malassezia species infection was higher among
patients aged 31-40 years (40% in 24 patients) and 21-30 years (35% in 21 patients). The chest region
had the greatest incidence of infection (37.33% in 23 patients) and neck (30.00% in 18 patients).
Observation of clinical data verified the existence of hyperpigmented lesions in 40 patients and
hypopigmented lesions in 20 patients. All isolates of Malassezia shown significant resistance to
ketoconazole, fluconazole, clotrimazole, amphotericin, and itraconazole treatments. Notably,
ten isolates exhibited the greatest sensitivity to nystatin.
Conclusion: The prevalence of Malassezia species infection is higher in males compared to
females, and it is quite uncommon in children. They either induce direct disease or actively contribute
to the progression of pre-existing skin disorders.