ABSTRACT
Photodynamic therapy (PDT) has been proved to be effective against fungi and it may be employed as a coadjutant to conventional antifungal agents, leading to a more effective microbial control minimising side effects. This work evaluates the combined effect of PDT and fluconazole against resistant Candida albicans, Candida glabrata and Candida krusei. The yeasts were submitted to methylene blue‑PDT (MB‑PDT) in sub‑inhibitory concentrations. In the present work, MB‑PDT combined with fluconazole was more efficient in the inhibition of the C. albicans and C. glabrata than each treatment alone, being possible to infer that the treatments are synergic.
ABSTRACT
Several studies have reported the occurrence of infections caused by Candida yeasts as well as the increasing prevalence of non albicans species. The aim of the present work is focused on the obtaining of heteroresistance to amphotericin B and fluconazole in Candida species using two distinct methodologies: selection and induction. Resistant samples were obtained by selective pressure using a medium with fluconazole for growth, followed by growth in a medium with amphotericin B. The selective pressure was also created beginning with growth in amphotericin B medium followed by growth in fluconazole medium. Concomitantly, samples were submitted to the induction of resistance through cultivation in increasing concentrations of fluconazole, followed by cultivation in increasing concentrations of amphotericin B. Subsequently, the induction began with amphotericin B followed by fluconazole. Three samples resistant to fluconazole and amphotericin B were obtained, two by induction (C. glabrata and C. tropicalis) and one by selection (C. tropicalis). Both C. tropicalis originated from the same wild sample. After successive transfers for drug free medium, only the sample obtained by selection was able to maintain the resistance phenotype. These results suggest that the phenotype of heteroresitance to fluconazole and amphotericin B can be produced by two methodologies: selection and induction.
Subject(s)
Antifungal Agents/analysis , Candida , Candidiasis , Drug Resistance, Microbial , Drug Resistance, Multiple, Fungal , Fluconazole/analysis , In Vitro Techniques , Yeasts , Drug Samples , Methods , Prevalence , MethodsABSTRACT
Denture stomatitis is an inflammatory condition that occurs in denture wearers and is frequently associated with Candida yeasts. Antifungal susceptibility profiles have been extensively evaluated for candidiasis patients or immunosupressed individuals, but not for healthy Candida carriers. In the present study, fluconazole, itraconazole, voriconazole, terbinafine and 5-flucytosin were tested against 109 oral Candida spp. isolates. All antifungal agents were effective against the samples tested except for terbinafine. This work might provide epidemiological information about Candida spp. drug susceptibility in oral healthy individuals.
A estomatite protética é uma condição inflamatória que ocorre em usuários de prótese total e está frequentemente associada a leveduras do gênero Candida, Os perfis de suscetibilidade a antifúngicos têm sido extensivamente estudados em pacientes com candidíase ou em indivíduos imunossuprimidos, mas não em portadores sadios de Candida. No presente estudo, fluconazol, itraconazol, voriconazol, terbinafina e 5-flucitosina foram testados contra 109 isolados orais de Candida spp. Todos os agentes antifúngicos mostraram-se eficazes contra as amostras avaliadas, exceto a Terbinafina. O presente trabalho pode fornecer dados epidemiológicos com relação à susceptibilidade a antifúngicos de Candida spp em indivíduos com saúde oral.