Identification and susceptibility of clinical isolates of Candida spp. to killer toxins

Abstract

Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an increasing problem. We analyzed 60 yeasts isolated from patients with invasive candidiasis using a PCR/RFLP strategy based on the internal transcribed spacer (ITS2) region to identify different Candida pathogenic species. PCR analysis was performed from genomic DNA with a primer pair of the ITS2-5.8S rDNA region. PCR-positive samples were characterized by RFLP. Restriction resulted in 23 isolates identified as C. albicans using AlwI, 24 isolates as C. parapsilosis using RsaI, and 13 as C. tropicalis using XmaI. Then, a group of all isolates were evaluated for their susceptibility to a panel of previously described killer yeasts, resulting in 75% being susceptible to at least one killer yeast while the remaining were not inhibited by any strain. C. albicans was the most susceptible group while C. tropicalis had the fewest inhibitions. No species-specific pattern of inhibition was obtained with this panel of killer yeasts. Metschnikowia pulcherrima, Pichia kluyveri and Wickerhamomyces anomalus were the strains that inhibited the most isolates of Candida spp. Keywords

Metschnikowia pulcherrima and Related Pulcherrimin-Producing Yeasts: Fuzzy Species Boundaries and Complex Antimicrobial Antagonism

“…The anti-microbial antagonism of Metschnikowia strains was occasionally proposed to be due killer toxins (e.g., [ 25 , 95 , 96 , 97 , 98 ]). However, no clear distinction was made between killer-induced inhibition and non-killer antagonism in these studies, and it can be inferred from the context that the term killer activity was used synonymously with the term antagonistic activity (e.g., antagonism associated with pulcherrimin production) which can be misleading.…”

Ação antimicrobiana de micocinas produzidas por Wickerhamomyces anomalus: uma revisão / Antimicrobial action of mycocins produced by Wickerhamomyces anomalus: a review

“…Embora já tenha sido relatado a capacidade de micocinas, ou toxinas killer, produzidas a partir de cepas de Wickerhamomyces anomalus inibir algumas espécies de Candida, estas não foram capazes de inibir completamente todos os grupos de espécies. A espécie Candida parapsilosis se mostrou resistente a estas micocinas (PARIS et al, 2016;ROBLEDO-LEAL et al, 2018). Há evidências de que a cepas de Wickerhamomyces anomalus isoladas de adultos e larvas de Phlebotomus perniciosus criados em laboratório, um dos principais vetores de leishmaniose humana e canina, podem exibir características killer.…”

iGENE: Aplicativo para identificação genômica de fungos filamentosos e leveduras

“…Métodos genômicos baseados em análise de polimorfismo por PCR/RFLP têm revelado eficiência na identificação de fungos e leveduras ao nível de espécie (Kordalewska et al, 2018, Robledo-Leal et al, 2018, Santos et al, 2019. Neste sentido, foi elaborado um aplicativo com o objetivo de proporcionar a identificação de fungos filamentosos e leveduras ao nível de espécie integrando metodologias genômicas, proteômicas e inteligência artificial.…”