In vitro susceptibility testing of Aspergillus spp. against voriconazole, itraconazole, posaconazole, amphotericin B and caspofungin

Background During recent years,the incidence of serious infections caused by opportunistic fungi has increaseddramatically due to alterations of the immune status of patients with hematological diseases,malignant tumors,transplantations and so forth.Unfortunately,the wide use of triazole antifungal agents to treat these infections has lead tothe emergence of Aspergillus spp.resistant to triazoles.The present study was to assess the in vitro activities of fiveantifungal agents （voriconazole,itraconazole,posaconazole,amphotericin B and caspofungin） against different kinds ofAspergillus spp.that are commonly encountered in the clinical setting.Methods The agar-based Etest MIC method was employed.One hundred and seven strains of Aspergillus spp.（5species） were collected and prepared according to Etest Technique Manuel.Etest MICs were determined with RPMIagar containing 2% glucose and were read after incubation for 48 hours at 35℃.MIC50,MICand MIC range wereacquired by Whonet 5.4 software.Results The MICof caspofungin against A.fumigatus,A.flavus and A.nidulans was 0.094 μg/ml whereas the MICagainst A.niger was 0.19 μg/ml.For these four species,the MICof caspofungin was the lowest among the fiveantifungal agents.For A.terms,the MICof posaconazole was the lowest.For A.fumigatus and A.flavus,the MICinorder of increasing was caspofungin,posaconazole,voriconazole,itraconazole,and amphotericin B.The MIC ofamphotericin B against A.terrus was higher than 32 μg/ml in all 7 strains tested.Conclusions The in vitro antifungal susceptibility test shows the new drug caspofungin,which is a kind ofechinocandins,has good activity against the five species of Aspergillus spp.and all the triazoles tested have better invitro activity than traditional amphotericin B.