Anti-Sporothrix brasiliensis activity of different pyrazinoic acid prodrugs: a repurposing evaluation

Sporothrix brasiliensis: Epidemiology, Therapy, and Recent Developments

Sporotrichosis caused by Sporothrix brasiliensis is an emergent mycosis that is now a worldwide concern. One important step to sporotrichosis control is its correct treatment. However, limitations abound; thus, new antifungals, mainly focused on S. brasiliensis, are urgently needed. We performed a systematic review (following the PRISMA guideline) focused on (1) the global distribution of human and animal sporotrichosis by S. brasiliensis, especially outside of Brazil; (2) appraising therapies tested against this pathogen. We identified sporotrichosis caused by S. brasiliensis reported in five countries (Paraguay, Chile, Argentina, the United Kingdom, and the United States) in addition to Brazil, occurring on three continents, highlighting the epidemiological scenario in Argentina with an important increase in reported cases in recent years. Regarding the antifungal activity of drugs, 25 articles described the in vitro action of 20 unique chemicals and eight repurposed drugs against S. brasiliensis. Only five studies reported in vivo activity against S. brasiliensis (five drugs) using invertebrate and vertebrate models. Sporotrichosis caused by S. brasiliensis has a global impact and it is no longer specifically a Brazilian problem. We review the need for understanding the disease epidemiology, education of clinicians and of the populace, organization of health care delivery to respond to a spreading epidemic, and research on therapy for sporotrichosis.

Benzylidene-carbonyl compounds are active against itraconazole-susceptible and itraconazole-resistant Sporothrix brasiliensis

We evaluated the antifungal activity of benzylidene-carbonyl compounds (LINS03) based on the structure of gibbilimbol from Piper malacophyllum Linn. Five analogues (1-5) were synthetized following a classic aldol condensation between an aromatic aldehyde and a ketone, under basic conditions. These were tested against itraconazole-susceptible (n = 3) and itraconazole-resistant (n = 5) isolates of Sporothrix brasiliensis by M38-A2 guidelines of CLSI. All of them were fungistatic (MIC ranged of 0.11-0.22 mg/mL (1); 0.08-0.17 mg/mL (2); 0.05-0.1 mg/mL (3); 0.04-0.33 mg/mL (4); and 0.04-0.3 mg/mL (5)), highlighting compounds 2 and 3. As fungicidal, compounds 1 and 2 were highlighted (MFC ranged of 0.22-0.89 mg/mL and 0.08-1.35 mg/mL, respectively), compared with the remaining (0.77-> 3.08 mg/mL (3); 0.08-> 2.6 mg/mL (4); and 0.59-> 2.37 mg/mL (5)). The inhibitory activity was related to the benzylidene-carbonyl, whereas the phenol group and the low chain homolog seems to contribute to some extent to the fungicidal effect. Compound 2 highlighted due to the considerable fungistatic and fungicidal activities, including itraconazole-resistant Sporothrix brasiliensis. These findings support the potential usefulness of benzylidene-carbonyl compounds as promising prototypes for the development of antifungal against sporotrichosis by Sporothrix brasiliensis, including against itraconazole-resistant isolates.

Feline sporotrichosis: a case series of itraconazole-resistant Sporothrix brasiliensis infection

The treatment of feline sporotrichosis is a challenge for veterinary clinicians since refractory cases may occur, due either to patient and/or to pharmacological management errors or due to the development of antifungal resistance. Thus, we aimed to describe the therapeutic history of feline cases infected by itraconazole-resistant Sporothrix brasiliensis in an endemic region of Southern Brazil. Medical records of cats attended at the Veterinary Clinic Hospital (Pelotas/RS, Brazil) between 2016 and 2017 were reviewed. Twelve cases of infection by S. brasiliensis with that showed high minimum inhibitory concentration (MIC) values (≥ 4 μg/mL) to itraconazole by M38-A2 of CLSI were selected. At the hospital consultation, disseminated (cats 1-l0, 12) and localized (cat 11) skin lesions remained in the cats, even after treatment with fluconazole, ketoconazole (02/12), and itraconazole (ITZ, 09/12) performed before this study. High doses (25-100 mg/kg/day) of ITZ for up to 4 months (03/12, cats 2, 6, 12) or over 12 months (05/12, cats 1, 5, 7, 8, 11) did not provide a clinical cure, except for the association of ITZ plus potassium iodide (01/12, cat 12) for 3 months, which proved useful in infections with itraconazole-resistant S. brasiliensis. However, the combined issues of abandonment of therapy by owners for financial reasons, difficulties surrounding therapy administration (03/12, cats 6, 11, 12), and the inappropriate choice of medication (01/12, cat 6), together reflect the reality of this endemic region, which greatly compromises clinical healing. This study highlighted the occurrence of refractory cases by itraconazole-resistant S. brasiliensis in cats from Southern Brazil, as well as the abandonment of treatment and therapeutic errors. We warn of the need for antifungal susceptibility tests to adapt therapeutic protocols in feline sporotrichosis.