has emerged as one of the most important
species. It has been widely considered the second most virulent
species, only preceded by
. Besides, this species has been recognized as a very strong biofilm ...producer, surpassing
in most of the studies. In addition, it produces a wide range of other virulence factors, including: adhesion to buccal epithelial and endothelial cells; the secretion of lytic enzymes, such as proteinases, phospholipases, and hemolysins, bud-to-hyphae transition (also called morphogenesis) and the phenomenon called phenotypic switching. This is a species very closely related to
and has been easily identified with both phenotypic and molecular methods. In addition, no cryptic sibling species were yet described in the literature, what is contradictory to some other medically important
species.
is a clinically relevant species and may be the second or third etiological agent of candidemia, specifically in Latin American countries and Asia. Antifungal resistance to the azoles, polyenes, and echinocandins has already been described. Apart from all these characteristics,
has been considered an osmotolerant microorganism and this ability to survive to high salt concentration may be important for fungal persistence in saline environments. This physiological characteristic makes this species suitable for use in biotechnology processes. Here we describe an update of
, focusing on all these previously mentioned subjects.
Amphotericin B (AmB), a potent antifungal drug, presents physicochemical characteristics that impair the development of suitable dosage forms. In order to overcome the AmB insolubility, several lipid ...carriers such as microemulsions have been developed. In this context, the bullfrog oil stands out as an eligible oily phase component, since its cholesterol composition may favor the AmB incorporation. Thus, the aim of this study was to develop a microemulsion based on bullfrog oil containing AmB. Moreover, its thermal stability, antifungal activity, and cytotoxicity
in vitro
were evaluated. The microemulsion formulation was produced using the pseudo-ternary phase diagram (PTPD) approach and the AmB was incorporated based on the pH variation technique. The antifungal activity was evaluated by determination of minimal inhibitory concentration (MIC) against different species of
Candida
spp. and
Trichosporon asahii
. The bullfrog oil microemulsion, stabilized with 16.8% of a surfactant blend, presented an average droplet size of 26.50 ± 0.14 nm and a polydispersity index of 0.167 ± 0.006. This system was able to entrap AmB up to 2 mg mL
−1
. The use of bullfrog oil as oily phase allowed an improvement of the thermal stability of the system. The MIC assay results revealed a growth inhibition for different strains of
Candida
spp. and were able to enhance the activity of AmB against
T. asahii
. The microemulsion was also able to reduce the AmB toxicity. Finally, the developed microemulsion showed to be a suitable system to incorporate AmB, improving the system’s thermal stability, increasing the antifungal activity, and reducing the toxicity of this drug.
Several studies have been developed regarding human health risks associated with the recreational use of beaches contaminated with domestic sewage. These wastes contain various micro-organisms, ...including
. In this context, the objective of this study was to characterize
isolates from the sandy beach of Ponta Negra, Natal, Rio Grande do Norte, Brazil, regarding the expression of
virulence factors, adaptation to osmotic stress and susceptibility to antifungal drugs. We analyzed 62 environmental isolates and observed a great variation among them for the various virulence factors evaluated. In general, environmental isolates were more adherent to human buccal epithelial cells (HBEC) than
ATCC13803 reference strain, and they also showed increased biofilm production. Most of the isolates presented wrinkled phenotypes on Spider medium (34 isolates, 54.8%). The majority of the isolates also showed higher proteinase production than control strains, but low phospholipase activity. In addition, 35 isolates (56.4%) had high hemolytic activity (hemolysis index > 0.55). With regard to
resistance to osmotic stress, 85.4% of the isolates were able to grow in a liquid medium containing 15% sodium chloride. The strains were highly resistant to the azoles tested (fluconazole, voriconazole and itraconazole). Fifteen strains were resistant to the three azoles tested (24.2%). Some strains were also resistant to amphotericin B (14 isolates; 22.6%), while all of them were susceptible for the echinocandins tested, except for a single strain of intermediate susceptibility to micafungin. Our results demonstrate that
isolated from the sand can fully express virulence attributes and showed a high persistence capacity on the coastal environment; in addition of showing high minimal inhibitory concentrations to several antifungal drugs used in current clinical practice, demonstrating that environmental isolates may have pathogenic potential.
is able to switch from yeast to hyphal growth and this is an essential step for tissue invasion and establishment of infection. Due to the limited drug arsenal used to treat fungal infections and the ...constant emergence of resistant strains, it is important to search for new therapeutic candidates. Therefore, this study aimed to investigate by proteomic analysis the role of a natural product (
) in impairing hypha formation in
. We also tested the potential action of
to prevent and treat oral candidiasis induced in a murine model of oral infection and the ability of polymorphonuclear neutrophils to phagocytize
cells treated with the ethyl acetate fraction of the extract. We found that this fraction greatly reduced hypha formation after morphogenesis induction in the presence of serum. Besides, several proteins were differentially expressed in cells treated with the fraction. Surprisingly, the ethyl acetate fraction significantly reduced phagocytosis in
(Mean 120.36 ± 36.71 yeasts/100 PMNs vs. 44.68 ± 19.84 yeasts/100 PMNs). Oral candidiasis was attenuated when
cells were either pre-incubated in the presence of
or when the fraction was applied to the surface of the oral cavity after infection. These results were consistent with the reduction in CFU counts (2.36 vs. 1.85 Log10 CFU/ml) and attenuation of tissue damage observed with histopathological analysis of animals belonging to treated group. We also observed shorter true hyphae by direct examination and histopathological analysis, when cells were treated with the referred natural product. The
ethyl acetate fraction was non-toxic to human cells.
may act on essential proteins mainly related to cellular structure, reducing the capacity of filamentation and attenuating infection in a murine model, without causing any toxic effect on human cells, suggesting that it may be a future therapeutic alternative for the treatment of
infections.
This study evaluated the influence of the extract of
in adhesion to human buccal epithelial cells (HBEC) biofilm formation and cell surface hydrophobicity (CSH) of
spp. isolated from the oral cavity ...of kidney transplant patients. To evaluate virulence attributes in vitro, nine yeasts were grown in the presence and absence of 1000 μg/mL of the extract. Adhesion was quantified using the number of
cells adhered to 150 HBEC determined by optical microscope. Biofilm formation was evaluated using two methodologies: XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2
-tetrazolium-5-carboxanilide) and crystal violet assay, and further analyzed by electronic scan microscopy. CSH was quantified with the microbial adhesion to hydrocarbons test. We could detect that the extract of
was able to reduce adhesion to HBEC and CSH for both
and non-
species. We also observed a statistically significant reduced ability to form biofilms in biofilm-producing strains using both methods of quantification. However, two highly biofilm-producing strains of
had a very large reduction in biofilm formation. This study reinforces the idea that besides growth inhibition,
may interfere with the expression of some virulence factors of
spp. and may be possibly applied in the future as a novel antifungal agent.
Candida albicans is a diploid yeast that in some circumstances may cause oral or oropharyngeal infections. This investigation aimed to study the prevalence of Candida spp. and to analyze the ABC ...genotypes of 76 clinical isolates of C. albicans obtained from the oral cavity of kidney transplant patients from two distinct geographic regions of Brazil.
We typed 48 strains with ABC genotyping and Microsatelitte using primer M13 and tested three virulence factors in vitro: phospholipase activity, morphogenesis and the ability to evade from polymorphonuclear neutrophils phagocytosis.
C. albicans was the most prevalent species (86.4%), followed by C. tropicalis (4.5%). C. albicans genotype A was the most prevalent (58 isolates; 76.4%), followed by genotype C (15 isolates; 19.7%) and genotype B (3 isolates; 3.9%). When Microsatellite technique with primer M13 was applied, 80% of the isolates from the South were placed within the same cluster. The majority of Genotype C strains were grouped together within two different clusters. Genotype C was considered more resistant to PMNs attack than genotypes A and B. Strains isolated from the South of Brazil showed also better ability to combat PMNs phagocytosis.
We found a high rate of C. albicans genotype C strains isolated from the oral cavity of this group of patients. This study characterized oral C. albicans strains isolated from kidney transplant recipients and will contribute to a better understanding of the pathogenesis of oral candidiasis.
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