Distribution, molecular characterization, and treatment options for dermatophyte and non-dermatophyte fungi isolated...

Cutaneous infections caused by dermatophytes and non-dermatophytes fungi have become significant public health and veterinary concern.

The current study deals with the distribution, characterization, and antifungal susceptibility profile of these fungi.

A total of 40 sample were screened by KOH mount; positive samples were cultured on SDA. Purified isolates were identified by macroscopic and microscopic characters. Molecular characterization by PCR and sanger sequencing of ITS region confirmed the fungi. Evolutionary trees were constructed using MEGA 11. Different treatment options were evaluated, including amphotericin B, nystatin, fluconazole, itraconazole, and essential oil of Nigella sativa. Initially molecular docking was performed against selected fungal targets (5eqb and 5v5z) using molecular-operating environment (MOE v.2018.01) and Maestro modeling interface 12.3. In vitro antimycotic activity was performed by agar disc diffusion, followed by micro-broth dilution method.

KOH mount revealed that 65% (13/20) samples positive for fungal components. Culture positivity for samples was 23.07% for dermatophytes and 76.92% for non-dermatophytes. Dermatophytes were detected in skin samples. However, non-dermatophytes were isolated from all types of samples. Sequence analysis confirmed the distribution of Arthroderma multifidum, Aspergillus sydowii, and Aspergillus sublatus. In-silico analysis revealed itraconazole as the most effective antimycotic agent with -7.93 kcal/mol (5eqb) and -10.89 (5v5z) kcal/mol. In vitro analysis strengthens docking analysis, itraconazole was the most effective agent with the highest mean ZOI against A. multifidum (72.00±3.46 mm), A. sydowii (62.00±3.00 mm), and A. sublatus (64.00±1.73 mm). Moreover, essential oil of N. sativa was the most effective antifungal against A. sydowii (ZOI; 31.00±3.46 mm, MIC; 3.125±0.00 mg/mL).

The current study is the first report of A. sydowii and A. sublatus in onychomycosis and hair infections in Pakistan. This study provides awareness about the existence of new fungal pathogens and highlights the availability of effective treatment options for emerging fungal infections.