Pseudomycelium forming Rhodotorula - unusual picture Rhodotorula wytwarzaj ca pseudomycelium - niezwyk y obraz biofilmu

Introduction: Rhodotorula yeast are easily identifiable by red colony formation. Species of the genus Rhodotorula are commensals in the natural environment and in mammals. Rhodotorula also infects individuals with predisposing risk factors but is rarely isolated as sole agent of opportunistic mycoses. Aim: We present a case report of unusual pseudomycelium forming Rhodotorula, that also be supposed causing acute gastrointestinal tract disorder. Materials and methods: Samples were taken from a hydration pack of a cyclist with gastrointestinal problems. Culture of samples on media did not show bacterial growth that could possibly be associated with the observed symptoms. Results: However, direct microscopic examination of swab samples of the hydration pack revealed the presence of yeast in a structure resembling a biofilm. A large number of blastospores with elongated large cells formed a pseudomycelium. This was supported by abundant typical red pigment yeast colonies growth identified as Rhodotorula rubra (mucilaginosa) on SDA after 48 h of incubation. Growth of other fungi was not observed. Hydrolase production capability of cells from the biofilm was exceptionally higher than that of planctonic cells. Our observation is a rare case of filamenting blastospores and pseudomycelium forming Rhodotorula. The possible association of Rhodotorula colonization with gastrointestinal disorder has not been reported before.