Background The prevalence of dermatophytoses and the development of new antifungal agents has focused interest on susceptibility tests of dermatophytes. The method used universally for susceptibility tests of dermatop...Background The prevalence of dermatophytoses and the development of new antifungal agents has focused interest on susceptibility tests of dermatophytes. The method used universally for susceptibility tests of dermatophytes was published as document （M38-A） in 2002 by the Clinical and Laboratory Standards Institute （CLSI）, dealing with the standardization of susceptibility tests in filamentous fungi, though not including dermatophytes especially. However, it is not a very practical method for the clinical laboratory in routine susceptibility testing. In this test, we developed a novel rapid susceptibility assay --glucose consumption method （GCM） for dermatophytes. Methods In this study, we investigated the antifungal susceptibilities of dermatophytes to itraconazole （ITC）, voriconazole （VOC）, econazole nitrate （ECN） and terbinafine （TBF） by glucose consumption method （GCM）, in comparison to the Clinical and Laboratory Standards Institute （CLSI） M38-A method. Twenty-eight dermatophyte isolates, including Trichophyton rubrum （T. rubrum） （n=-14） and Trichophyton mentagrophytes （T. mentagrophytes） （n=-14）, were tested. In the GCM, the minimum inhibitory concentrations （MICs） were determined spectrophotometrically at 490 nm after addition of enzyme substrate color mix. For the CLSI method, the MICs were determined visually. Results Comparison revealed best agreement for TBF against T. mentagrophytes and T. rubrum, since MIC range, MIC50, and MIC90 were identical from two methods. However, for ITC and VOC, GCM showed wider MIC ranges and higher MICs than CLSI methods in most isolates. For ECN against T. rubrum, high MICs were tested by GCM （0.125-16 pg/ml） but not M38-A method （0.5-1 IJg/ml）. The overall agreements for all isolates between the two methods within one dilution and two dilutions for ITC, VOC, ECN and TBF was 53.6% and 75.0%, 57.1% and 75.0%, 82.1% and 89.3%, and 85.7 and 85.7%, respectively. Conclusion Measurement of glucose uptake can predict the susceptibility of T. rubrum and T. mentagrophytes to ECN and TBF.展开更多
To performance susceptibility testing of antifungal agents Due to the increasing number of resistant strains, susceptibility testing of antifungal agents is gaining importance Methods We compared the results of s...To performance susceptibility testing of antifungal agents Due to the increasing number of resistant strains, susceptibility testing of antifungal agents is gaining importance Methods We compared the results of standard macrotube dilution reference method with two different microdilution methods, as well as the disc diffusion method in order to test the susceptibility of 150 Candida strains to fluconazole Results Overall correlation between microdilution and macrodilution methods was 86% It was 91% between the Minimal Inhibitory Concentrations obtained from macrodilution and disc diffusion zone diameters Conclusion The disc diffusion test was evaluated as a low-cost, reproducible, and efficient way of assessing the in vitro susceptibility of Candida strains to fluconazole展开更多
基金This study was supported by a grant from the Guangdong Natural Science Foundation Committee （No. 06300760）.Acknowledgement： We thank Dr. XIE Zhi from Department of Dermatology and Venereology, The Second Affiliated Hospital of Sun Yat-Sen University, for his critical review of the manuscript.
文摘Background The prevalence of dermatophytoses and the development of new antifungal agents has focused interest on susceptibility tests of dermatophytes. The method used universally for susceptibility tests of dermatophytes was published as document （M38-A） in 2002 by the Clinical and Laboratory Standards Institute （CLSI）, dealing with the standardization of susceptibility tests in filamentous fungi, though not including dermatophytes especially. However, it is not a very practical method for the clinical laboratory in routine susceptibility testing. In this test, we developed a novel rapid susceptibility assay --glucose consumption method （GCM） for dermatophytes. Methods In this study, we investigated the antifungal susceptibilities of dermatophytes to itraconazole （ITC）, voriconazole （VOC）, econazole nitrate （ECN） and terbinafine （TBF） by glucose consumption method （GCM）, in comparison to the Clinical and Laboratory Standards Institute （CLSI） M38-A method. Twenty-eight dermatophyte isolates, including Trichophyton rubrum （T. rubrum） （n=-14） and Trichophyton mentagrophytes （T. mentagrophytes） （n=-14）, were tested. In the GCM, the minimum inhibitory concentrations （MICs） were determined spectrophotometrically at 490 nm after addition of enzyme substrate color mix. For the CLSI method, the MICs were determined visually. Results Comparison revealed best agreement for TBF against T. mentagrophytes and T. rubrum, since MIC range, MIC50, and MIC90 were identical from two methods. However, for ITC and VOC, GCM showed wider MIC ranges and higher MICs than CLSI methods in most isolates. For ECN against T. rubrum, high MICs were tested by GCM （0.125-16 pg/ml） but not M38-A method （0.5-1 IJg/ml）. The overall agreements for all isolates between the two methods within one dilution and two dilutions for ITC, VOC, ECN and TBF was 53.6% and 75.0%, 57.1% and 75.0%, 82.1% and 89.3%, and 85.7 and 85.7%, respectively. Conclusion Measurement of glucose uptake can predict the susceptibility of T. rubrum and T. mentagrophytes to ECN and TBF.
文摘To performance susceptibility testing of antifungal agents Due to the increasing number of resistant strains, susceptibility testing of antifungal agents is gaining importance Methods We compared the results of standard macrotube dilution reference method with two different microdilution methods, as well as the disc diffusion method in order to test the susceptibility of 150 Candida strains to fluconazole Results Overall correlation between microdilution and macrodilution methods was 86% It was 91% between the Minimal Inhibitory Concentrations obtained from macrodilution and disc diffusion zone diameters Conclusion The disc diffusion test was evaluated as a low-cost, reproducible, and efficient way of assessing the in vitro susceptibility of Candida strains to fluconazole
