| Malassezia species is a kind of yeast-like fungus with lipophilis character and colonizes the skin surface of healthy individuals.Malassezia folliculitis is one of the Malassezia related diseases,often cause itching and pain on the affected areas. It has been gradually concerned that the disease usually needs a prolonged treatment,but is easy to relapse.This study aim is to investigate the sensitivities to antifungal agents of 4 Malassezia species from the pathogenic of Malassezia folliculitis,as well as detect the expression of lipase activity of the 4 species.It is important for the epidemiological investigation of Malassezia folliculitis and the guidance of clincal medication.Objective:1.To understanding the sensitivity of 5 kinds of antifungal agents against 82 clinical isolates of Malassezia globosa,M.sympodialis,M.furfur,and M.obtusa in vitro.2.To detect the lipase activity of Malassezia from various specimens(isolated from clinical specimens and isolative from normal person), meanwhile compare the lipase activity of sensitive strains with resistant strains.Methods:The typical lesion with 10%KOH microscopic examination being positive,which were isolated from 112 patients who were diagnosed of Malassezia folliculitis in the Second Hospital of Lanzhou University during the period from January to December of 2008,were cultured respectively on the media containing rapeseed oil.The Malassezia isolates were identified according to their biochemical, physiological and morphological characteristics.Standard strains were tested as controls.The minimal inhibitory concentration(MIC) of ketoconazole,itraconazole, fluconazole,econazole and terbinafine against these species in vitro were tested by M27-A microdilution method recommended by Clinical and Laboratory Standards Institute(CLSI).P-nitropheny palmitate(PNP) was used as lipase substrate to detect the lipase activity of 82 strains isolated from clinical specimens and 68 strains isolated from normal person,at the same time,to find the difference in the lipase activity of sensitive strains,dose-dependented strains,and drug resistant strains in the drug susceptibility test.Results:1.The 82 clinical strains isolated from 112 patients of Malassezia folliculitis were cultured out malassezia spp.(positive rate 73.2%).The Malassezia isolates were identified as 4 species,including M.globosa(52),M.sympodialis(21), M.furfur(7),and M.obtusa(2).2.For the 82 strains,the MIC ranges were＜0.03～0.5μg/ml for ketoconazole,＜0.03～0.25μg/ml for itraconazole,1～64μg/ml for fluconazole,0.125～0.5μg/ ml for econaazole,and 0.06～4μg/ml for terbinnafine.3.There was significant difference in lipase activity between the 82 strains isolated from clinical specimens and the 68 strains isolated from normal person(P＜0.01).4.The sensitivity of 52 Malassezia globosa to fluconazole in accordance with M27-A program was divided into three groups,sensitive group (40),dose-dependent sensitive group(9),resistance group(3).There were no significant difference in the expression of lipase activity in the three groups (P＞0.05).Conclusions:1.Malassezia globosa is the main species of Malassezia folliculitis,followed by the Malassezia sympodialis.2.All Malassezia species were highly sensitive to ketoconazole,itraconazole,econazole,and terbinafine,whereas fluconazole displayed higher MIC value to M.globosa and 3 resistant strains of Malassezia was found.3.The lipasea activity of strains isolated from clinical samples were higher than that of which isolated from normal person.It seems that the lipase activity may correlate with the virulence.4.In vitro susceptibility against fluconazole and the expression of lipase activity of Malassezia are possible of two independent factors.
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