Abstract: Objective To evaluate the performance of modified dermatophyte test medium (DTM) compared with conventional DTM in the diagnosis of onychomycosis.Methods Nail samples were collected from patients with suspicious onychopathy,and inoculated into modified DTM,DTM, Sabouraud dextrose agar fortified with cycloheximide and chloromycetin (SCCA) and Sabouraud dextrose agar fortified with chloromycetin (SCA) respectively.The initial time of fungal growth and of discoloration of medium,as well as the colony diameter at the beginning of discoloration,were documented.All the results were compared with those from a reference mycologic laboratory.Results The fungal isolation rate, growth speed and colonial appearance were of no difference among modified DTM,DTM and SCCA.All isolates of dermatophyte could alter the color of both modified DTM and DTM.The time needed for discoloration was shorter in modified DTM than in DTM (5.83±0.39 days vs.7.32±0.41 days,t=2.63,P=0.01).Although most isolates of nondermatophyte could also produce a discoloration,they could be distinguished from dermatophytes by colony diameters at the beginning of discoloration (≥5 mm),and the differentiation results according to this criterion were in a good agreement with those from a reference mycology laboratory.Conclusions Compared to conventional methods,DTM and modified DTM result in a more rapid identification (by 7 days).Compared to DTM,modified DTM is more economical,and results in an earlier color change.However,further research is needed.

Key words: Tinea, Arthro dermataceae, Culture media, Indicators and reagents