Molecular epidemiology, in vitro susceptibility and exoenzyme screening of Malassezia clinical isolates

Abstract

Introduction.Malasseziafolliculitis (MF) and pityriasis versicolor (PV) are common dermatoses caused byMalasseziaspecies. Their molecular epidemiology, drug susceptibility and exoenzymes are rarely reported in China.Aim.To investigate the molecular epidemiology, drug susceptibility and enzymatic profile ofMalasseziaclinical isolates.Methodology.Malasseziastrains were recovered from MF and PV patients and healthy subjects (HS) and identified by sequencing analysis. The minimum inhibitory concentrations (MICs) of nine antifungals (posaconazole, voriconazole, itraconazole, fluconazole, ketoconazole, miconazole, bifonazole, terbinafine and caspofungin) and tacrolimus, the interactions between three antifungals (itraconazole, ketoconazole and terbinafine) and tacrolimus, and the extracellular enzyme profile were evaluated using broth and checkerboard microdilution and the Api-Zym system, respectively.Results.Among 392Malasseziaisolates from 729 subjects (289 MF, 218 PV and 222 HS),Malassezia furfurandMalassezia globosaaccounted for 67.86 and 18.88 %, respectively.M. furfurwas the major species in MF and PV patients and HS. Among 60M.furfurand 50M.globosastrains, the MICs for itraconazole, posaconazole, voriconazole and ketoconazole were <1 μg ml−1.M. furfurwas more susceptible to itraconazole, terbinafine and bifonazole but tolerant to miconazole compared withM. globosa(P<0.05). Synergistic effects between terbinafine and itraconazole or between tacrolimus and itraconazole, ketoconazole or terbinafine occurred in 6, 7, 6 and 9 out of 37 strains, respectively. Phosphatases, lipases and proteases were mainly secreted in 51 isolates.Conclusions.Itraconazole, posaconazole, voriconazole and ketoconazole are theagents against which there is greatest susceptibility. Synergistic effects between terbinafine and itraconazole or tacrolimas and antifungals may be irrelevant to clinical application. Overproduction of lipases could enhance the skin inhabitation ofM. furfur.