中华皮肤科杂志

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改良皮肤癣菌试验培养基的实验研究

李筱芳, 沈永年, 陈伟, 陈辉, 吕桂霞, 刘维达   

  1. 中国医学科学院、中国协和医科大学皮肤病研究所 南京 210042
  • 收稿日期:2006-01-20 出版日期:2006-04-15 发布日期:2006-04-15

Study on the optimization of dermatophyte test medium(DTM)

LI Xiao-fang, SHEN Yong-nian, CHEN Wei, CHEN Hui, LÜ Gui-xia, LIU Wei-da   

  1. Department of Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences & Peking Union Medical College, Nanjing 210042, China
  • Received:2006-01-20 Online:2006-04-15 Published:2006-04-15

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摘要： 目的 对皮肤癣菌试验培养基(DTM)作适当改进,筛选出最佳配方.方法 ①采用正交设计法和单因素分组试验对培养基的主要影响因子进行量和质的优化组合,筛选出改良培养基.②将红色毛癣菌标准菌株菌悬液倍比稀释,接种于DTM和改良培养基上,测定检出灵敏度.③将3属18种皮肤癣菌和11属14种非皮肤癣菌的丝状真菌接种于DTM和改良培养基上,比较特异性.结果 培养基的氮源、碳源、pH值和指示剂的调整对变色时间的影响差异无统计学意义(P>0.05),从经济和早期判断颜色是否改变的难易程度考虑,确定改良培养基主要配方:0.5%大豆蛋白胨,0.5%葡萄糖,指示剂为溴百里酚监.DTM和改良培养基的检出灵敏度均为103cth/mL(10cfu/培养基).所有受试的皮肤癣菌均能使两种培养基变色,相对变色时间(开始变色时间-开始生长时间)DTM为-2～0d,改良培养基为-4～0d;绝大多数受试的霉菌也能使两种培养基变色,相对变色时间DTM为1～5d,改良培养基为1～6d.结论 改良培养基的配方比DTM经济,较DTM再易观察到早期颜色的改变.

关键词: 关节皮肤真菌科, 培养基, 诊断

Abstract: Objective To improve the sensitivity of dermatophyte test medium (DTM) by optimizing its formula.Methods ①The effects of 4 key factors of DTM (nitrogen source,carbon source,pH value and indicator) were studied using orthogonal experiment and oneway grouped tests.②Ten-fold serial dilutions of Trychophyton rubrum suspension were placed on either DTM or reformed medium to determine the lowest limit of detection (sensitivity).③In order to evaluate the specificity of the assays,inoculation of a large number of fungus strains (18 species in 3 genus of dennatophyte and 14 species in 11 genus of mold) was also carried out in the above two types of medium.Results ①None of the modification of nitrogen source,carbon source,pH value and indicator in the medium had any significant effect (P>0.05) on the time of discoloration.The optimal formula,which was the most economical and convenient for recognition of discoloration,was 0.5% soy peptone and 0.5% glucose,with bromothymol blue as the indicator.②The sensitivity was 103 cfu/mL (10 cfu/medium) for both DTM and reformed medium.③All tested dermatophytes could alter the color of both media.Although most tested moulds could also result in a color change,their relative time of discoloration (the beginning time of discoloration minus that of growth) was≥1 day,whereas that of dennatophytes was≤0 day.Conclusions The reformed medium was more economical;it is also superior for early recognization of discoloration than DTM.

Key words: Arthrodermataceae, Culture media, Diagnosis