Candidacidal Activity of a Novel Killer Toxin from Wickerhamomyces anomalus against Fluconazole-Susceptible and -Resistant Strains

Abstract

The isolation and characterization from the sand fly Phlebotomus perniciosus of a Wickerhamomyces anomalus yeast strain (Wa1F1) displaying the killer phenotype was recently reported. In the present work, the killer toxin (KT) produced by Wa1F1 was purified and characterized, and its antimicrobial activity in vitro was investigated against fluconazole- susceptible and -resistant clinical isolates and laboratory strains of Candida albicans and C. glabrata displaying known mutations. Wa1F1-KT showed a differential killing ability against different mutant strains of the same species. The results may be useful for the design of therapeutic molecules based on Wa1F1-KT and the study of yeast resistance mechanisms.

Identification of a Killer Toxin from Wickerhamomyces anomalus with β-Glucanase Activity

“…The yeast W. anomalous produces several KTs, each characterized by variable molecular weights, a large range of optimal pH and temperature and a wide antimicrobial activity against several microorganisms [16,17]. The Wa F1.712 strain was previously isolated from the malaria vector A. stephensi and was shown to release a protein molecule that targets cell wall glucans with killer activity against other sensitive yeast strains/species and which is recognized by a monoclonal antibody specific for killer yeast toxins [9,10].…”

Wickerhamomyces anomalus in Mosquitoes: A Promising Yeast-Based Tool for the “Symbiotic Control” of Mosquito-Borne Diseases

“…This finding fits well possible antimicrobial competition of W. anomalus in the mosquito body, since different physiological conditions occur in different organs (midgut and gonads). Likely in mosquitoes, a killer strain of W. anomalus displaying a killer phenotype and candidacidal activity has been isolated also in larvae and adults (male and female) of the sand fly P. pernicious ( Martin et al, 2016 ; Giovati et al, 2018 ).…”

Killer Yeasts And Their Application

“…W temperaturze 25°C toksyna nie wykazywała aktywności killerowej wobec referencyjnego szczepu C. albicans SC5314, wrażliwych na flukonazol izolatów klinicznych (C. albicans DSY347 i DSY544) oraz mutanta DSY775 opornego na flukonazol, pochodzącego od szczepu C. albicans DSY544. Toksyna była aktywna w stosunku do mutanta DSY289 opornego na flukonazol, wywodzącego się od szczepu C. albicans SY347, a także wobec wszystkich użytych w badaniu, wrażliwych i opornych na flukonazol, izolatów klinicznych C. glabrata i ich mutanów [30].…”