Sporotrichosis caused by Sporothrix brasiliensis in Argentina: Case report, molecular identification and in vitro susceptibility pattern to antifungal drugs

Abstract

Sporotrichosis is considered a neglected disease of humans and animals in many regions of the world and is the most frequent implantation mycosis in Latin America.

Objectives: To illustrate the zoonotic importance of the disease, describing a case involving a veterinarian and an infant that acquired the disease from a domestic cat and to describe, genotype and characterize these new isolates.

Methods: Direct examination of tissue samples from the two patients and feline lesions revealed the presence of Sporothrix yeast-like organisms. Fungal cultures and molecular identification of the strains were performed. Since antifungal susceptibility data of animal-borne isolates are scarce, the in vitro susceptibility testing by a microdilution reference method was determined against azoles, amphotericin B and terbinafine.

Results: Fungal culture and sequence analysis of the ITS region of rDNA and calmodulin and β-tubulin genes confirmed the diagnosis and the causative agent as Sporothrix brasiliensis. In all cases, terbinafine was the most active drug, followed by posaconazole, itraconazole and voriconazole; the least active drugs were amphotericine B and fluconazole. Lack of clinical response in the veterinarian and in the infant to itraconazole and potassium iodide, respectively was observed.

Conclusions: This study contributed to the molecular epidemiology of Sporothrix species in Argentina and the characterization of the in vitro susceptibility pattern of S. brasiliensis isolates recovered from a cat and two humans involved in this case of zoonotic sporotrichosis. Bearing in mind the "One Health" concept, the experience described in the present study highlights the need for future strategies for sporotrichosis treatment, control and prevention.

Keywords: Argentina; Domestic cat (Felis catus); Infant; Sporothrix brasiliensis; Sporotrichosis; Veterinarian.