Dermatophytes

A 42-year-old male construction worker from Delhi presents with a 2-month history of progressive nail dystrophy affecting multiple toenails. He reports thickening, discoloration (yellow-brown), and subungual debris accumulation. Nail clippings sent for KOH mount show branching septate hyphae. Culture on Sabouraud dextrose agar grows a slow-growing, white colony with a leather-like texture and radial grooves. Which organism is most likely isolated?

A 28-year-old woman from Mumbai presents with a 3-week history of pruritic, scaly patches on her forearms and lower legs. Examination reveals well-demarcated, erythematous plaques with central clearing and a raised, scaling border. KOH mount of scale shows branching septate hyphae. She reports recent contact with stray cats in her neighborhood. Which dermatophyte is most likely responsible for this infection?

Which of the following dermatophytes is anthropophilic and most commonly causes tinea corporis in India?

Which morphological feature distinguishes Trichophyton schoenleinii from other anthropophilic dermatophytes under microscopy?