The interaction between Sporothrix schenckii sensu stricto and Sporothrix brasiliensis with Acanthamoeba castellanii.

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.

Papiliotrema leoncinii sp. nov. and Papiliotrema miconiae sp. nov., two tremellaceous yeast species from Brazil.

Two yeast species, Papiliotrema leoncinii sp. nov. and Papiliotrema miconiae sp. nov., in the family Rhynchogastremataceae of the Tremellales are proposed. The two species are related to six species of the genus Papiliotrema: Papiliotrema aureus, P. flavescens, P. terrestris, P. baii, P. ruineniae and P. wisconsinensis. The novel species are proposed on the basis of the sequence-based phylogenetic species concept with analysis of the D1/D2 region of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region. A total of 16 strains of Papiliotrema leoncinii sp. nov. were obtained from freshwater and bromeliad leaves collected in Brazil. Papiliotrema leoncinii sp. nov. differs by 11, 12, 16, 14, 11 and 13 substitutions in the D1/D2 domain from the related species P. aureus, P. flavescens, P. terrestris, P. baii, P. ruineniae and P. wisconsinensis, respectively. Differences of 11 substitutions and 21 or more substitutions in ITS regions were found when the sequences of Papiliotrema leoncinii sp. nov. were compared with P. wisconsinensis and its closest relatives. The type strain of Papiliotrema leoncinii sp. nov. is UFMG-CM-Y374T (=CBS 13918T). Papiliotrema miconiae sp. nov. is represented by two strains isolated from a flower of Miconia sp. and a water sample in Brazil. Papiliotrema miconiae sp. nov. differs from the related species P. aureus and P. ruineniae by eight substitutions, from P. flavescens and P. terrestris by 11 substitutions, from P. baii by 10 substitutions and from P. wisconsinensis by 6 substitutions in the D1/D2 domain, and by 7 substitutions from P. wisconsinensis and more than 19 substitutions in the ITS region from its closest relatives. The type strain of Papiliotrema miconiae sp. nov. is CBS 8358T (ML 3666T=DBVPG-4492T). The MycoBank numbers for Papiliotrema leoncinii sp. nov. and Papiliotrema miconiae sp. nov. are MB 813594 and MB 814882, respectively.