Eumycetoma, a chronic
fungal infection endemic in India, Indonesia, and parts of Africa and South and Central America, follows traumatic implantation of saprophytic fungi and frequently requires radical surgery or
amputation in the absence of appropriate treatment. Fungal species that can cause black-grain mycetomas include Madurella spp., Falciformispora spp., Trematosphaeria grisea, Nigrograna mackinnonii, Pseudochaetosphaeronema larense, Medicopsis romeroi, and Emarellia spp. Rhytidhysteron rufulum and Parathyridaria percutanea cause similar subcutaneous
infections, but these
infections lack the draining sinuses and fungal grains characteristic of
eumycetoma. Accurate identification of the agents of subcutaneous
fungal infection is essential to guide appropriate antifungal
therapy. Since phenotypic identification of the causative fungi is often difficult, time-consuming molecular approaches are currently required. In the study described here we evaluated whether matrix-assisted
laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry might allow the accurate identification of
eumycetoma agents and related fungi. A panel of 57 organisms corresponding to 10 different species from confirmed cases of
eumycetoma and subcutaneous pedal masses, previously formally identified by PCR amplification and sequencing of internal transcribed spacer 1 (ITS1), was employed. Representative isolates of each species were used to create reference MALDI-TOF spectra, which were then used for the identification of the remaining isolates in a user-blinded manner. Here, we demonstrate that MALDI-TOF mass spectrometry accurately identified all of the test isolates, with 100%, 90.4%, and 67.3% of isolates achieving log scores greater than 1.8, 1.9, and 2.0, respectively.