Investigation On The Pathogenic Fungi Of Malassezia Folliculitis In Lanzhou District

Background:Malassezia folliculitis is a chronic recurrent dermatomycosis caused by Malassezia species.With the wide application of glucocorticoid,antibiotics, immunodepressant,and change of diet structure,the incidence of Malassezia folliculitis is increasing.Many scholars have been reported the distribution of Malassezia species in Malassezia folliculitis.It is well established that an understanding of the prevalence and identity of etiological agents are helpful in the prevention and treatment of Malassezia folliculitis.However,very few data has been published about the prevalence and types of Malassezia folliculitis,what etiologic agents presenting,and how the pathogenic fungi being diversified in Lanzhou district.Objective:1.To investigate the clinical features and the pathogenic species of Malassezia folliculitis in Lanzhou district.2.To inquire into the application of rapid and precise identification for the pathogenic species of Malassezia folliculitis by using molecular methods.Methods:The specimens from clinically suspected patients with Malassezia folliculitis were examined for causative fungi during January 2008 to December 2008 in the Second Hospital of Lanzhou University.The samples from the follicular contents being positive in the directly microscopic examination were recorded and analyzed.Then the follicular contents were seeded onto medium containing rapeseed oil and the isolates were identified to species by physiological,biochemical and morphological characteristics.The internal transcribed spacer(ITS) region of ribosomal DNA were amplified by using the fungi-universal primers ITS1 (5'-TCCGTAGGTGAACCTGCGG-3')and ITS4(5'-TCCTCCGCTTATTGATATGC-3'), then the PCR products were sequenced and analyzed.Results:1.The one hundred twelve patients comprised 89 men and 23 women (M/F sex ratio:3.87:1) with a mean age of 26.08 years,18-30 years 90 cases,7-9 month 53 cases.The lesions of 70 patients distributed on the chest and 42 on the back. There were 18 cases of being treated systematically with glucocorticoid before,27 cases of oil skin,2 cases of hyperthyreosis,2 cases of tuberculosis,and 32 cases of profuse sweating.2.The eighty two strains of Malassezia spp.were isolated from all the patients enrulled and the positive rate was 73.21%,in which 4 speies were identified,including 52 strains(63.42%) of M.globosa,21 strains(25.61%) of M. sympodialis,7 strains(8.54%) of M.furfur,and 2 strains(2.43%) of M.obtusa.3.The patterns of 39 strains of Malassezia were isologous after the primer-pair ITS1 and ITS4 being amplified,and a fragment about 750bp was obtained in all strains.4.The results of sequencing were in full accordance with the results of physiological, biochemical and morphological identification.Conclusions:1.Malassezia folliculitis occurs predominantly in the young and during the hot season.The lesions distribute mainly on the chest and back.Systemic treatment of glucocorticoids,oil skin and profuse sweating make patients prone to be infected.2.The dominant species of Malassezia folliculitis is M.globosa in Lanzhou district.There are not correlative between constitution of Malassezia species and different anatomic sites or the severity of disease.3.The primer-pair ITS1 and ITS4 could not distinguish Malassezia species and the further identification by sequencing and other methods should be taken.