Evaluation of the effect of Ziziphus joazeiro var. Mart on Candida spp. bloodstream isolates virulence factors
Candida spp., virulence factors, candidemia, sinthethic antifungals, Ziziphus joazeiro.
Background: Bloodstream infections represent an important public health
problem, with attributed mortality of 40-60%. In addition to their known in vitro
virulence potential, Candida spp. have been drawing attention to the growing
number of reports of resistance to antifungal drugs, representing a serious
problem for the treatment of infections caused by these microorganisms.
Objectives: This study aimed to evaluate the antifungal susceptibility of Candida
spp. from patients with Candida bloodstream infection against synthetic antifungal
compounds, as well as an enriched fraction obtained from the extract of Ziziphus
joazeiro. We also investigated the interference of this natural product on the
expression of Candida spp. virulence factors. Material and methods: Seventy
Candida spp. isolates from blood cultures were analyzed. The microdilution broth
technique was performed to investigate the susceptibility of the isolates against
synthetic antifungals. Subsequently, 50 isolates were selected and the evaluation
of the antifungal activity of the fraction was performed. A total of 27 isolates were
selected for virulence factor expression assays in the absence and presence of
the fraction. Results: None of the isolates presented resistance to amphotericin B
and caspofungin. 4 isolates of C. albicans and 1 isolate of C. glabrata were
resistant to fluconazole, whereas 3 isolates of C. albicans, 1 of C. tropicalis and 2
of C. parapsilosis complex showed dose-dependent susceptibility to this drug.
Nine isolates of C. albicans, 6 of C. tropicalis, 2 of C. glabrata and 1 of C.
parapsilosis complex showed a dose-dependent susceptibility to itraconazole. The
isolates identified as C. albicans and C. glabrata were susceptible to the fraction
with MFCs ranging from 5000-10000 μg/mL. The strains treated with the fraction
showed a reduction of about 26% in the capacity of adhesion buccal epithelial
cells, a lower production of phospholipase and a decrease in filamentation
capacity, with IM varying between IM= 1.51 to IM= 2.63. Conclusion: The
enriched fraction of Z. joazeiro presents significant antifungal activity, being able to
interfere with the expression of virulence factors in vitro of this group of yeasts.
Further studies should be performed in order to evaluate the mechanisms of action
involved.