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.

Cryosurgery for the treatment of cutaneous sporotrichosis in four pregnant women.

BACKGROUND: Pregnant women with sporotrichosis should not receive systemic antifungal therapy except in severe cases when amphotericin B is recommended. Thermotherapy is the most reported treatment described in this group of patients. It entails weeks of daily self-application of heat to the lesions, requires that the patient faithfully apply it, and it could cause skin burns. Cryosurgery is a useful therapeutic tool for many cutaneous infectious diseases, safe for pregnant women, but not well evaluated for sporotrichosis treatment in this group. METHODOLOGY: The authors conducted a retrospective study describing epidemiological, clinical, and therapeutic data related to four pregnant patients with sporotrichosis treated with cryosurgery. The authors reviewed the clinical records of four pregnant patients diagnosed with cutaneous sporotrichosis and treated with cryosurgery. The sessions were carried out monthly up to clinical cure. Molecular identification of the Sporothrix species was performed in two cases using T3B PCR fingerprinting assays. PRINCIPAL FINDINGS: All patients were in the second trimester of pregnancy and their age ranged from 18 to 34 years. With regard to clinical presentation, two patients had lymphocutaneous and two had the fixed form. S. brasiliensis was identified in two cases as the causative agent. Cryosurgery was well tolerated and the number of sessions ranged from 1 to 3. All the patients reached a complete clinical cure. CONCLUSIONS: Cryosurgery was a safe, easy to perform and well tolerated method, and therefore it is suggested to be a suitable option for the treatment of cutaneous sporotrichosis in pregnant women.

Antifungal curcumin promotes chitin accumulation associated with decreased virulence of Sporothrix schenckii.

Curcumin, a yellow polyphenol compound, is known to possess antifungal activity for a range of pathogenic fungi. However, the fungicidal mechanism of curcumin (CUR) has not been identified. We have occasionally found that chitin redistributes to the cell wall outer layer of Sporothrix schenckii (S. schenckii) upon sublethal CUR treatment. Whether CUR can affect chitin synthesis via the protein kinase C (PKC) signaling pathway has not been investigated. This study describes a direct fungicidal activity of CUR against S. schenckii demonstrated by the results of a checkerboard microdilution assay and, for the first time, a synergistic effect of CUR with terbinafine (TRB). Furthermore, the results of real-time PCR showed that sublethal CUR upregulated the transcription of PKC, chitin synthase1 (CHS1), and chitin synthase3 (CHS3) in S. schenckii. The fluorescence staining results using wheat germ agglutinin-fluorescein isothiocyanate (WGA-FITC) and calcofluor white (CFW) consistently showed that chitin exposure and total chitin content were increased on the conidial cell wall of S. schenckii by sublethal CUR treatment. A histopathological analysis of mice infected with CUR-treated conidia showed dampened inflammation in the local lesion and a reduced fungal burden. The ELISA results showed proinflammatory cytokine secretion at an early stage from macrophages stimulated by the CUR-treated conidia. The present data led to the conclusion that CUR is a potential antifungal agent and that its fungicidal mechanism may involve chitin accumulation on the cell wall of S. schenckii, which is associated with decreased virulence in infected mice.

Efficacy of posaconazole in murine experimental sporotrichosis.

We developed a murine model of systemic sporotrichosis by using three strains of each of the two commonest species causing sporotrichosis, i.e., Sporothrix schenckii sensu stricto and Sporothrix brasiliensis, in order to evaluate the efficacy of posaconazole (PSC). The drug was administered at a dose of 2.5 or 5 mg/kg of body weight twice a day by gavage, and one group was treated with amphotericin B (AMB) as a control treatment. Posaconazole, especially at 5 mg/kg, showed good efficacy against all the strains tested, regardless of their MICs, as measured by prolonged survival, tissue burden reduction, and histopathology.

Effects of hyperthermia on phagocytosis and intracellular killing of Sporothrix schenckii by polymorphonuclear leukocytes.

The effects of hyperthermia on phagocytosis and killing of Sporothrix schenckii by polymorphonuclear leukocytes (PMNs) were investigated in order to clarify the mechanism of local thermotherapy for sporotrichosis. Yeast cells of S. schenckii, PMNs and serum were incubated at 37 degrees C or 40 degrees C for 2 or 4 hours. Rate of phagocytosis and killing rate (rate of germination) were estimated, and their processes were observed by transmission electron microscopy. There was no effect of hyperthermia on the phagocytosis rate, but the killing rate increased significantly at 40 degrees C. Electron microscopic examination showed an increase of granularity in the yeast cytoplasm, elongation and fragmentation of the cell membrane. The ultrastructural changes were basically identical under both temperatures, but the degree of these changes was higher at 40 degrees C than at 37 degrees C. Although both intact and degenerated yeasts were found in the same conditions, their transient forms were few, suggesting that the PMN-killing process was completed promptly.

The effects of heat on Sporothrix schenckii in vitro and in vivo.

In order to clarify the mechanism of action of topical thermotherapy on sporotrichosis, the effects of heat on Sporothrix schenckii in vitro and in vivo were investigated by observing the percentage germination and the ultrastructure. When the spores were heated to 42 degrees C, it took 10 hr with the conidia, 2 hr with the yeast-like cells and 1 hr with the spores in vivo to reduce the germination rates to 10%. The percentage germination curves were reduced slowly at first but later exponentially. Changes in the ultrastructure became evident in 2 hr with the yeast-like cells and in 8 hr with the conidia. The ribosome count declined and amorphous dense materials appeared in the cytoplasm and mitochondria. In vivo, the outstanding feature of the heated spores was the diversity of internal ultrastructural changes encountered and morphological changes. These were observed at 1 hr post treatment.