[Onychomycosis Caused by Phoma glomerata: The First Reported Case from Türkiye]

Onychomycosis is a nail infection most commonly caused by dermatophytes. However in recent years, non-dermatophyte molds have also been increasingly reported as causative agents of onychomycosis. Phoma glomerata is a saprophytic fungus commonly found in nature, which rarely causes infections in humans and to date, only one case has been reported in another country as a causative agent of onychomycosis. In this case report, a case of onychomycosis caused by P.glomerata was presented. A 67-year-old female patient admitted to the dermatology outpatient clinic of our hospital with a oneyear history of discoloration, thickening and fragility of the left big toenail. In the potassium hydroxide microscopic examination of the specimen taken from the nail bed, septate and branched hyphae were observed. Dark brown pigmented, slow-growing mold colonies were observed within 10 days of culture on Sabouraud dextrose agar. Microscopic examination revealed the presence of pycnidial structures. The fungus isolated from the patient was identified as P.glomerata using the VITEK MS Mould Kit with the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) (VITEK MS, bioMérieux, France) system and DNA sequencing analysis was performed to confirm the diagnosis. Following genomic DNA extraction, the 28S rRNA gene region was amplified by polymerase chain reaction (PCR) using the NL1 and NL4 primers. After agarose gel electrophoresis of the PCR products, the amplicons were sequenced using the SQK-NBD114.96 kit on the MinION (Oxford Nanopore, United Kingdom) platform. The obtained data were analyzed using the BLAST algorithm in the National Center for Biotechnology Information GenBank database. The sequence was submitted to the NCBI GenBank under the accession number PV975047. The patient was treated with oral terbinafine (250 mg/day) and topical antifungal therapy. Clinical improvement was observed after two months of follow-up. In this study, we present a case of onychomycosis caused by P.glomerata in an elderly diabetic patient living in a rural area. According to our literature review, this is the first case reported from Türkiye and the second worldwide. Current scientific data suggest that Phoma species can cause infections in the skin, subcutaneous tissues or other organs, especially in immunocompromised or debilitated individuals, or following penetrating trauma. Classical phenotypic methods pose significant challenges in identifying this agent and MALDI-TOF MS or molecular methods may be useful for accurate identification.