In Vitro Antifungal Drug Susceptibility of Feline Sporothrix schenckii Complex Isolates, Thailand, 2023-2025

Feline sporotrichosis is a public health concern because it is a zoonotic illness and has a prolonged treatment time. We report laboratory-confirmed cases of feline Sporothrix schenckii complex infection submitted to a laboratory in Thailand during 2023-2025 and evaluate their in vitro antifungal drug susceptibility profiles for amphotericin B, itraconazole, posaconazole, voriconazole, ketoconazole, fluconazole, and flucytosine. A total of 1,178 S. schenckii complex isolates were identified. Overall, 368 isolates did not show reduced susceptibility. We observed single-drug reduced susceptibility to amphotericin B (60 isolates), posaconazole (41 isolates), voriconazole (9 isolates), and terbinafine (4 isolates). We observed a reduced susceptibility to itraconazole in 687 isolates: 321 single-drug, 270 co-reduced, and 96 multidrug-reduced isolates. An increasing number of feline sporotrichosis cases and escalating reduced susceptibility to itraconazole underscore the need for continued surveillance and susceptibility testing to support management in complex cases.