Navegando por Palavras-chave "Azole Resistance"

Agora exibindo 1 - 1 de 1
  • Imagem de Miniatura
    Item
    Acesso aberto (Open Access)
    Avaliação de resistência aos antifúngicos e virulência em isolados de Candida tropicalis provenientes de infecções de corrente sanguínea
    (Universidade Federal de São Paulo (UNIFESP), 2019-12-18) Favarello, Larissa Molina [UNIFESP]; Melo, Analy Salles De Azevedo [UNIFESP]; http://lattes.cnpq.br/8922840487452492; http://lattes.cnpq.br/0360899625657312; Universidade Federal de São Paulo (UNIFESP)
    Objective: To evaluate isolates of Candida tropicalis from bloodstream infections from Brazilian medical centers included in surveillance studies (2007-2018) to evaluate susceptibility to azoles and to characterize potential virulence in vivo model with the nematode Caenorhabditis elegans. Material and Methods: Clinical isolates stored in the LEMI Microorganism Bank previously identified by phenotypic methods such as Candida tropicalis were selected. The isolates were thawed and seeded on Sabouraud dextrose agar and CHROMagar® Candida media for reactivation and purity evaluation; Species were confirmed by the Matrix-Assisted Laser Desorption Ionization - Time of Flight Mass (MALDI-TOF MS, Bruker®) method using 25% formic acid in a protein extraction protocol; In vitro susceptibility was performed with the antifungals: amphotericin B, fluconazole, voriconazole and anidulafungin using the broth microdilution method recommended by the Clinical & Laboratory Standards Institute (CLSI), document M27ED4. Concomitantly, the prevalence of trailing with low-high phenotype was observed for azole antifungals; virulence was evaluated using the survival curve in C. elegans specimens infected with C. tropicalis, C. albicans, C. auris reference strains and clinical isolates of C. tropicalis according to azole resistance profiles. Results: 200 sequential isolates were recovered from hospitalized patients with positive blood cultures, which were previously identified by phenotypic methods as C. tropicalis over the period of 2007 to 2018. The sequencing of 21 clinical isolates (10.5%) and the reference strain C. tropicalis ATCC 750 was performed to improve the in-house protein database. The other 179 C. tropicalis isolates (89.5%) were properly identified using the in-house database (MALDI-TOF MS). Regarding the susceptibility profile, all isolates were susceptible to amphotericin B, one isolate was resistant to anidulafungin. It was found that 3.5% of the isolates were non-susceptible to azoles. To facilitate the analysis, we divided the isolates into two periods: P1 (2007-2012) and P2 (2013-2018). In P1 (2007-2012) the resistance rate was 1.9% for fluconazole and 0% for voriconazole, being found for P2 (2013-2018) resistance rate of 3.2% for fluconazole and 1% for voriconazole, no statistical difference was observed (p = 0.42). The virulence assay with C. elegans was observed on the second day after infection, the survival rate for C. auris was 90%; 50% for C. albicans; and 0%\20% for the clinical isolate (1534/17) and reference strains (ATCC 750) of C. tropicalis respectively. Conclusions: (i) It was possible to accurately identify by the MALDI-TOF MS method the isolates of C. tropicalis, after enriching the in house database; (ii) Five isolates of C. tropicalis with resistance profile to azole antifungals were found; (iii) Comparing the periods P1 and P2, there was an increase tendency in the rate of azoles resistance, but there was no statistical difference; (iv) One anidulafungin resistant C. tropicalis isolate was found; (v) Survival curves with C. elegans suggested that C. tropicalis, regardless of susceptibility profile, was more virulent than C. auris (P <0.05).