Sporotrichosis is a neglected subcutaneous fungal infection that affects humans and animals worldwide caused by species belonging to the genus Sporothrix. This study aims to examine the range of genetic variations, assess molecular epidemiology significance, and explore potential modes of transmission of the Sporothrix species associated with the current sporotrichosis outbreaks in Espírito Santo, Brazil. In this investigation, 262 samples were evaluated, including 142 from humans and 120 from felines, collected between 2016 and 2021. The isolates were identified based on morphological and molecular characteristics. Sexual idiomorphs were determined by mating-type PCR using primers specific to the MAT1-1 and MAT1-2 loci. Amplified fragment length polymorphism (AFLP) was employed to assess the genetic variability of Sporothrix spp. Finally, antifungal susceptibility testing was performed following the CLSI M38-A2 protocol. Of the 142 human samples, 125 were identified as S. brasiliensis and 17 as S. schenckii s. str. The presence of S. brasiliensis was overwhelming (100%) during outbreaks, highlighting the significant role of domestic cats in the emergence of this species. Heterothallism was the only observed mating strategy. However, the MAT1-2 idiomorph was predominant in cases of cat-transmitted sporotrichosis (χ² = 202.976; p < 0.0001). Our AFLP results show significant intraspecific variability observed among S. brasiliensis isolates in Espírito Santo. Different genotypes forming subgroups within the same population suggest that these isolates do not originate from a single ancestor, indicating multiple emergences. Furthermore, terbinafine was the antifungal with the best results in vitro. However, in clinical practice, itraconazole remains the primary treatment choice. Sporotrichosis continues to advance in the state; therefore, the health system must outline one-health strategies to contain the disease to prevent future epidemics.

Sporotrichosis is a serious fungal disease of humans and animals worldwide. The ongoing epidemic of cat-transmitted sporotrichosis caused by Sporothrix brasiliensis in South America raises major public health concerns, yet data on environmental persistence and disinfectant efficacy are scarce. Using the quantitative disk carrier method (ASTM 2197), we evaluated persistence and disinfectant susceptibility of Sporothrix schenckii and Sporothrix brasiliensis yeasts on hard, non-porous stainless-steel surfaces. Both species remained viable for at least 6 weeks, supporting the potential for fomite-mediated transmission. We tested seven disinfectant formulations. Sodium hypochlorite (NaOCl) 10,000 ppm (1.0%) and 70% isopropyl alcohol achieved >6 Log ₁₀ reduction for both species with 3 min contact time. Intermediate activity was observed with 1,000 ppm (0.1%) NaOCl at 3 min against S. schenckii . For both species, <3 Log ₁₀ reduction was observed for 100 ppm (0.01%) NaOCl tested at 3 min contact time, and three veterinary-market products—an accelerated hydrogen peroxide product (Product H ₂ O ₂ ) for 1 min, a quaternary ammonium compound (Product QAC), and a potassium peroxymonosulfate product (Product KPS)—tested at 10 and 5 min, respectively. These results demonstrate prolonged surface survival of Sporothrix spp. and identify which disinfectants are effective or ineffective under the tested conditions, concentrations, and contact times. This evidence can guide infection-control practices in clinical and veterinary settings. Notably, 70% isopropyl alcohol is a non-corrosive, less irritating alternative, making it useful for protecting animal patients and veterinary equipment. IMPORTANCE: Cat-transmitted sporotrichosis is an emerging public health concern in South America and is increasingly reported in other continents. Although primarily zoonotic, recent evidence indicates Sporothrix spp. can be transmitted via contaminated surfaces and fomites, raising the risk of indirect transmission and nosocomial spread. Effective surface disinfection is therefore critical—particularly in veterinary clinics—but guidance is limited by a lack of rigorous testing of disinfectant activity against Sporothrix species. Our study fills this gap by assessing the environmental persistence of Sporothrix schenckii and Sporothrix brasiliensis on surfaces and by evaluating the efficacy of seven disinfectant formulations. These results will inform evidence-based infection-control practices to reduce fomite-mediated transmission and protect human and animal health.