No abstract

Sporotrichosis is an infection with global distribution caused by the dimorphic fungi of the genus Sporothrix, whose main pathogenic species include Sporothrix schenckii, Sporothrix brasiliensis, Sporothrix globosa, and Sporothrix luriei. Itraconazole and amphotericin B are the most used antifungals for the treatment. The aim of this review was to compile the in-vitro susceptibility data of Sporothrix spp. found in literature and correlate this data with the treatment guidelines for sporotrichosis. The systematic review was performed according to the Cochrane methodology and with PICOS (Participants, Intervention, Comparators, Outcomes, Study Design) strategy. Thirty-six studies were included that used the filamentous and/or the yeast phases to perform the susceptibility tests. Three studies that evaluated the association of antifungals using the checkerboard method were also included. The data found were, whenever possible, compared with the defined Epidemiological Cutoff Values (ECVs). Analyzing only the minimum inhibitory concentration (MIC) values, the most effective antifungal in vitro was terbinafine. However, this is not the same result as observed in vivo. Both itraconazole and amphotericin B presented in-vitro activity. However, many studies have shown that isolates can acquire resistance mechanisms to these antifungals (MIC > ECV), which deserves attention. Further studies are needed to translate in-vitro susceptibility data into clinical practice, and also to determine ECVs for more antifungals and Sporothrix species.

Summary Background Sporotrichosis is a group of zoonotic subcutaneous mycoses, found worldwide and caused by fungi belonging to the genus Sporothrix. Protozoans of the genus Acanthamoeba are widely distributed, and some species may be pathogenic and/or opportunistic. These organisms coexist in the same environment and may interact. Objectives This study determined the profile of interactions of S schenckii sensu stricto and S brasiliensis with A castellanii, using an in vitro co‐culture model to evaluate the intrinsic characteristics of the two Sporothrix species and A castellanii. Methods We compared the rate of phagocytosis of S schenckii sensu stricto and S brasiliensis by A castellanii; the viability of S schenckii sensu stricto and S brasiliensis after contact with A castellanii; the viability of the amoeba after contact with a fungal species; and the influence of S schenckii sensu stricto and S brasiliensis on the encystment process of A castellanii. Results The analyses indicated that A castellanii phagocytised both S schenckii and S brasiliensis, with significantly more S schenckii than S brasiliensis in the first two hours of contact. Our results showed a significant increase in conidia and hyphae count after 72 hours of co‐culture of A castellanii with S brasiliensis, and the amoebae lysed after they ingested the fungi, indicating that the fungi probably used the amoebae as a source of nutrition. Conclusions Our results were obtained in vitro and these organisms may not behave similarly in vivo; in vivo studies of co‐infections are necessary in order to gain a thorough understanding of this relationship.

We evaluated the growth and the susceptibility to oxidative stress of Sporothrix spp., exposed to different iron concentrations in culture medium, and the susceptibility of Sporothrix spp. to itraconazole, alone and in combination with to the iron chelator deferasirox. The results showed that the growth of S. brasiliensis isolates was more affected by iron availability in comparison to S. schenckii, but both fungal species conidia became more prone to oxidative stress when iron was added to culture medium. Conversely, the combination of itraconazole and deferasirox only resulted in synergism against a minority of S. schenckii isolates.