Identification of Malassezia Species in Pityriasis Versicolor.

Rathnapriya, N (2008) Identification of Malassezia Species in Pityriasis Versicolor. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION : The skin is the body’s largest and thinnest organ. Approximately, 15 percent of all patients who seek medical attention have either some skin disease or skin lesion, many of which are infectious. Fungi are ubiquitous in the environment. Fungal infections of the skin are a health concern worldwide. Clinical fungal infections are generally divided into four types namely, cutaneous, subcutaneous systemic and opportunistic mycosis. Superficial mycosis are by far the most common. Superficial fungal infections are defined as infections in which a pathogen is restricted to the stratum corneum, with little or no tissue reaction. One of the superficial fungal infections of the skin is Pityriasis versicolor. Tinea versicolor, also known as Pityriasis versicolor, is one of the most common pigmentary disorders worldwide. In the United States, the name Tinea versicolor is commonly used, whereas Pityriasis versicolor is the common name in Europe. Perhaps, European colleagues are correct, since the name “Tinea” suggests that the infection is caused by a dermatophyte, which, of course, is untrue. In view of the wide spectrum of diseases caused by Malassezia spp. it was, therefore, felt necessary to study the most common Malassezia spp. associated with patients having Pityriasis versicolor and analyse the risk factors leading to the infection. AIMS AND OBJECTIVES : 1. To identify the yeasts isolated from clinically diagnosed patients with Pityriasis versicolor. 2. To evaluate Modified Dixon’s Agar for isolation of the Malassezia species. 3. To compare Modified Dixon’s Agar and Sabouraud Dextrose Agar with Olive oil overlay for isolation of Malassezia spp. 4. To speciate the Malassezia isolates using Tween Assimilation Tests. 5. To analyse the risk factors which promote Malassezia fungus infection. MATERIALS AND METHODS : This cross sectional study was done in the Institute of Microbiology, Madras Medical College and the Mycology section of the Department of Dermatology, Government General Hospital, Chennai from July 2005 to June 2006. The study group included both male and female outpatients of all age groups, attending the mycology section of the Department of Dermatology, with complaints of hypopigmented or hyperpigmented macular lesions. The skin scrapings were collected from 112 clinically diagnosed patients with Pityriasis versicolor. RESULTS : Pityriasis versicolor accounted for 16.6 percent patients with dermatomycoses in Government General Hospital, Chennai. Majority of the study population belonged to the age range 21-30 years. Male patients out numbered female patients. Maximum number of cases occurred during July to August. Majority of patients had hypopigmented lesions. Majority of patients presented within 2 months of onset of the lesion. Chest and back regions were the most commonly affected sites. Lower limb, hip palms, soles, and gluteal regions were not involved. Both mounts found to be equally sensitive. Out of 104 Pityriasis versicolor patients, only 66(63.46%) were culture positive for Malassezia yeast. Modified Dixon’s Agar had 7.69% higher isolation rates than SDA with Olive oil overlay. Modified Dixon’s Agar had 7.69% higher isolation rates than SDA with Olive oil overlay. M. globosa was the predominant species isolated in Pityriasis versicolor cases. Increased sweating was identified to be the predominant risk factor. Increased sweating was found to be the statistically significant risk for Pityriasis versicolor with P value of 0.0001. No conjugal relationship was not seen in this study.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Identification ; Malassezia Species ; Pityriasis Versicolor.
Subjects: MEDICAL > Microbiology
Depositing User: Subramani R
Date Deposited: 16 Aug 2017 00:34
Last Modified: 16 Aug 2017 01:11

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