Pestalotioid fungi: A rare agent of onychomycosis among agriculture workers

BACKGROUND AND PURPOSE: Pestalotioid fungi are ubiquitous environmental molds that have received considerable attention in recent times not only because of their role as a plant pathogen but also owing to their high frequency of retrieval from human diseases. Regarding this, the present study was conducted to investigate onychomycosis caused by pestalotioid fungi, commonly considered important phytopathogens causing grey blight disease in Camellia sinensis. MATERIALS AND METHODS: A total of 122 agriculture workers were enrolled from Assam, India. Direct microscopic examination was carried out using 40% KOH to determine the presence of any fungal element. Further processing of the specimens for the isolation of fungi was performed using the standard protocol. In addition, the keratinolytic potential of the isolates was evaluated by means of the in vitro hair perforation test. RESULTS: Out of 103 culture-positive samples, non-dermatophyte and dermatophyte molds constituted 82.52% (n=85) and 6.79% (n=7) of the samples, followed by yeasts (n=1, 0.9%) and sterile hyphae (n=10, 9.7%). With regard to the isolated non-dermatophyte molds (82.69%), 4 cases belonged to pestalotioid fungi, such as Neopestalotiopsis piceana (n=1), Pestalotiopsis species (n=1), and Pseudopestalotiopsis theae (n=2). The keratinolytic activity of Pestalotiopsis species showed perforation by disrupting the hair cortex; furthermore, macroconidia were found to be present inside the human hair. CONCLUSION: A high rate of NDM isolation may be attributed to constant exposure to adverse environmental and occupational hazards. This study highlighted the importance of “pestalotioid fungi” as the rare etiologic agent of onychomycosis. Another remarkable finding was the keratinolytic potential of Pestalotiopsis species, which is unique in this study.