Trichosporon inkin fungemia case report: clinical and laboratory management

Trichosporon species are emerging as opportunistic pathogens that mainly affect immunocompromised patients. Patients with onco-hematological diseases usually present with fungemia by Trichosporon species, especially by T. asahii. Reports of this infection by other species of the genus are uncommon. Thus, in this paper, we present a case of T. inkin fungemia in a 39-year-old female patient with intestinal obstruction and absence of malignant hematological diseases. The late mycological diagnosis, the ineffective control of her pre-existing conditions and consequent failure to start antifungal therapy were the contributing factors for the patient's death.

Trichosporon asahii and Trichosporon inkin Biofilms Produce Antifungal-Tolerant Persister Cells

Persister cells are metabolically inactive dormant cells that lie within microbial biofilms. They are phenotypic variants highly tolerant to antimicrobials and, therefore, associated with recalcitrant infections. In the present study, we investigated if Trichosporon asahii and T. inkin are able to produce persister cells. Trichosporon spp. are ubiquitous fungi, commonly found as commensals of the human skin and gut microbiota, and have been increasingly reported as agents of fungemia in immunocompromised patients. Biofilms derived from clinical strains of T asahii (n=5) and T. inkin (n=7) were formed in flat-bottomed microtiter plates and incubated at 35°C for 48 h, treated with 100 μg/ml amphotericin B (AMB) and incubated at 35°C for additional 24 h. Biofilms were scraped from the wells and persister cells were assayed for susceptibility to AMB. Additionally, we investigated if these persister cells were able to generate new biofilms and studied their ultrastructure and AMB susceptibility. Persister cells were detected in both T asahii and T. inkin biofilms and showed tolerance to high doses of AMB (up to 256 times higher than the minimum inhibitory concentration). Persister cells were able to generate biofilms, however they presented reduced biomass and metabolic activity, and reduced tolerance to AMB, in comparison to biofilm growth control. The present study describes the occurrence of persister cells in Trichosporon spp. and suggests their role in the reduced AMB susceptibility of T. asahii and T. inkin biofilms.

Prospecção fitoquímica e avaliação antimicrobiana de Sida planicaulis Cav. (Malvaceae) sobre leveduras potencialmente patogênicas

As espécie vegetais são utilizadas cada vez mais como fontes medicinais para a descoberta de moléculas biologicamente ativas. A espécie Sida planicaulis Cav. apresenta uma distribuição por todo o território brasileiro, é conhecida popularmente como vassoura e utilizada na medicina popular para tratar dor no corpo. Embora haja seu uso pela comunidade, esta espécie não possui estudos químicos ou farmacológicos comprovados cientificamente. Portanto, este trabalho objetivou determinar a composição química do extrato etanólico bruto (EEB) e das fases hexânica, clorofórmica, acetato de etila e hidroalcoolica de Sida planicaulis Cav. avaliando o potencial fúngico frente leveduras potencialmente patogênicas, utlizando os valores dos halos de inibição para determinar a atividade antifúngica. Observou-se na prospecção fitoquímica a presença de alcalóides, flavonóides, esteróides, triterpenos, saponinas e taninos. As leveduras Candida tropicalis, Geotrichum 57839, Rhodotorula spp e Trichosporon inkin LM- 67 apresentaram resistência frente ao EEB e às respectivas fases de Sida planicaulis Cav., não sendo observado halo de inibição. O estudo contribui para extração, purificação e isolamento de futuros metabólitos secundários. Sugere então que EEB e as fases de Sida planicaulis Cav. não sejam utilizados para tratar infecções causadas por estes fungos.