Sporotrichosis in dogs: epidemiological and clinical-therapeutic profile and the emergence of itraconazole-resistant isolates

Sporotrichosis is a neglected and emerging mycosis caused by the traumatic implantation of Sporothrix propagules into the (sub)cutaneous tissues of humans and animals. We evaluated canine sporotrichosis's clinical-therapeutic, epidemiological profile, and in vitro susceptibility of isolates to itraconazole. The variables were evaluated by a chi-square test. A total of 69 dogs were infected with Sporothrix spp., and the molecular identification revealed an overwhelming occurrence of S. brasiliensis as the etiological agent. The epidemiological profile was male (56.5%), adults (4.9 ± 1.92 years old; 69.6%), and mongrels (53.6%). The clinical signs were 76.8%, ulcers, draining tracts, and nodules were predominant, mainly in the nasal region (82.2%). Dogs were diagnosed late with an evolution time of up to 3 months (34.8%). According to the prior therapeutic information, 52.2% received empirical therapy, 79.2% antibiotics, and had a 0.29 significantly greater chance of presenting lesion evolution time ˃ 3 months (P < .05; Odds Ratio [OR] 1/0.29). Additionally, 25 S. brasiliensis isolates recovered between 2006-2012 (n = 15; Minimal inhibitory concentration (MIC): 0.06-2 μg/ml) and 2013-2018 (n = 10; MIC: 2→16 μg/ml) were tested against itraconazole (ITZ). These findings highlighted the resistance to ITZ in clinical cases due to S. brasiliensis occurring after 2013, showing the temporal evolution of ITZ-resistance. We warn of the importance of accurate and early diagnosis in Sporothrix-affected areas, and we report the emergence of ITZ-resistant isolates in Southern Brazil.