RESUMEN
We have previously reported on the activity of different extracts from Astronium sp. against Candida albicans, with the hydroethanolic extract prepared from leaves of A. urundeuva, an arboreal species widely distributed in arid environments of South America and often used in folk medicine, displaying the highest in vitro activity. Here we have further evaluated the antifungal activity of this extract against strains of C. albicans and C. glabrata, the two most common etiological agents of candidiasis. The extract was tested alone and loaded into a nanostructured lipid system (10% oil phase, 10% surfactant and 80% aqueous phase, 0.5% Poloxamer 407®). In vitro susceptibility assays demonstrated the antifungal activity of the free extract and the microemulsion against both Candida species, with increased activity against C. glabrata, including collection strains and clinical isolates displaying different levels of resistance against the most common clinically used antifungal drugs. Checkerboard results showed synergism when the free extract was combined with amphotericin B against C. albicans. Serial passage experiments confirmed development of resistance to fluconazole but not to the free extract upon prolonged exposure. Although preformed biofilms were intrinsically resistant to treatment with the extract, it was able to inhibit biofilm formation by C. albicans at concentrations comparable to those inhibiting planktonic growth. Cytotoxicity assays in different cell lines as well as an alternative model using Artemia salina L. confirmed a good safety profile of the both free and loaded extracts, and an in vivo assay demonstrated the efficacy of the free and loaded extracts when used topically in a rat model of vaginal candidiasis. Overall, these results reveal the promise of the A. urundeuva leaves extract to be further investigated and developed as an antifungal.
RESUMEN
We have conducted a longitudinal study over a 3-year period to address the point prevalence, microbiological characteristics and antifungal susceptibility patterns of yeast isolates colonizing or infecting the oral cavities of 111 HIV-infected (51 adults, 60 children) and 201 non HIV-infected (109 adults, 92 children) Mexican persons. Regarding the epidemiology of oral candidiasis, Candida albicans was the most frequent species isolated. Seventy-one out of 85 isolates from colonized persons were C. albicans (83.5%), 27 isolates of them were from HIV-infected children and 44 from non HIV-infected patients. Sixty-two isolates belonged to serotype A which was the most prevalent serotype of C. albicans. Non-albicans species (Candida glabrata, Candida tropicalis and Candida parapsilosis, and Saccharomyces cerevisiae) were isolated from 16.5% of colonized patients and from 38.5% patients with candidiasis or Candida-related lesions. There were nine episodes of infection or colonization by at least 2 different yeast species. In the case of HIV/AIDS patients, it was determined that yeast carriage was not associated with the number of CD4+ cells or the viral load, but HAART reduced the prevalence of oral candidiasis. Overall, most patients harbored strains in vitro susceptible to fluconazole, however 10.8% of the yeasts were resistant to one or more azole antifungal agents and 29% were intermediate susceptible to them. On the contrary, 5-fluorocytosine was very active against all isolates tested, and amphotericin B was active against 97.9% of them.
Asunto(s)
Candida/aislamiento & purificación , Candidiasis Bucal/epidemiología , Infecciones por VIH/epidemiología , Infecciones Oportunistas Relacionadas con el SIDA/tratamiento farmacológico , Infecciones Oportunistas Relacionadas con el SIDA/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Terapia Antirretroviral Altamente Activa , Recuento de Linfocito CD4 , Candida/clasificación , Candida/efectos de los fármacos , Candida albicans/efectos de los fármacos , Candida albicans/aislamiento & purificación , Candida glabrata/efectos de los fármacos , Candida glabrata/aislamiento & purificación , Candida tropicalis/efectos de los fármacos , Candida tropicalis/aislamiento & purificación , Candidiasis Bucal/tratamiento farmacológico , Candidiasis Bucal/microbiología , Niño , Preescolar , Comorbilidad , Femenino , Infecciones por VIH/tratamiento farmacológico , Humanos , Lactante , Masculino , México/epidemiología , Persona de Mediana Edad , Mucosa Bucal/microbiología , Prevalencia , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/aislamiento & purificación , Carga ViralRESUMEN
Oral yeast carriage was studied in 312 Mexican subjects. Candida albicans was the most frequent species, but other Candida spp. were isolated from 16.5 to 38.5% of patients. Colonization did not correlate with CD4+ number or viral load, but highly active antiretroviral therapy reduced the frequency of candidiasis. Most isolates were susceptible to fluconazole, but 10.8% were resistant to one or more azoles.