Susceptibility of Candida albicans Isolated from Blood to Wickerhamomyces anomalous Mycocins

Antimicrobial activity of immobilized mycocins in sodium alginate on fecal coliforms

Wickerhamomyces anomalus is a yeast-producing mycocins and has antimicrobial action. Escherichia coli is the predominant bacterium of the coliforms group; its presence in water indicates fecal contamination, being used as an indicator of microbiological analyses. The immobilization of cells and substances demonstrates great potential for biotechnological applications. This work aimed to assess the activity of free and immobilized mycocins, obtained from W. anomalus, against E. coli strains and fecal coliforms. The mycocins were immobilized in different concentrations of sodium alginate and calcium chloride and tested to verify the antimicrobial activity against the E. coli strain and fecal coliforms present in water samples. The mycocins were able to inhibit all strains used in broth microdilution. Considering the problem of multidrug-resistant antibiotic strains and the need for new alternatives to improve the quality of water and sewage effluents, these results demonstrate a possible application as an alternative to an antimicrobial agent.

Action of mycocins produced by Wickerhamomyces anomalus on Malassezia pachydermatis isolated from the ear canal of dogs

This study aims to examine the effectiveness of mycocins produced by Wickerhamomyces anomalus in inhibiting Malassezia pachydermatis, a yeast commonly found in the ear canal of dogs. M. pachydermatis has a zoophilic origin and can be found in mammals, and frequently in dogs, where it mainly colonizes the ear canal region and the skin, leading to lesions that are difficult to treat. The antimicrobial mechanism was evaluated using dilutions of supernatant with enzymatic activity, which may include β-glucanases, glycoproteins known to act on microorganism cell walls. However, it is important to note that this supernatant may contain other compounds as well. β-glucanases in the mycocins supernatant were found at a concentration of 0.8 U/mg. The susceptibility of M. pachydermatis isolates was tested using the microdilution method. The isolates suffered 100% inhibition when tested with the culture supernatant containing mycocins. In the proteinases production test, 44% of the isolates tested were strong proteinases producers. Subsequently all these isolates suffered inhibition of their activity when tested in research medium containing mycocins supernatant at a subinhibitory concentration of β-glucanases. This shows that mycocins can inhibit the production of proteinases, a virulence factor of M. pachydermatis. The viability test showed the antifungal action of mycocins in inhibiting the viability of M. pachydermatis cells after a period of 8  hours of contact. These results support the antimicrobial potential of mycocins and their promise as a therapeutic option.

Overview on the Infections Related to Rare Candida Species

Atypical Candida spp. infections are rising, mostly due to the increasing numbers of immunocompromised patients. The most common Candida spp. is still Candida albicans; however, in the last decades, there has been an increase in non-Candida albicans Candida species infections (e.g., Candida glabrata, Candida parapsilosis, and Candida tropicalis). Furthermore, in the last 10 years, the reports on uncommon yeasts, such as Candida lusitaniae, Candida intermedia, or Candida norvegensis, have also worryingly increased. This review summarizes the information, mostly related to the last decade, regarding the infections, diagnosis, treatment, and resistance of these uncommon Candida species. In general, there has been an increase in the number of articles associated with the incidence of these species. Additionally, in several cases, there was a suggestive antifungal resistance, particularly with azoles, which is troublesome for therapeutic success.

Susceptibility of Candida albicans Strains Isolated from Vaginal Secretion in Front of the Mycocins of Wickerhamomyces anomalus

Mycocins are substances that have the potential to affect other sensitive yeasts or microorganisms. Wickerhamomyces anomalus is a yeast that produces mycocins that have great biotechnological potential, being highly competitive in many habitats, as it is adaptable to a wide range of environmental conditions. Thus, they are targets for studies in different areas, including the environment, industry, and medical sciences. Yeasts of the genus Candida are of great importance due to the high frequency with which they colonize and infect the human host. Yeast infections are often difficult to treat due to the acquisition of resistance against antifungals, leading to studies focusing in new treatment alternatives. This work aims to verify the inhibition of Candida albicans isolated from vaginal secretion by mycocins produced by Wickerhamomyces anomalus. Tests were carried out in solid medium and microdilution tests, where mycocins proved to be efficient in inhibiting the growth of C. albicans, hemolysis, and irritation in an organotypic model, which showed that the mycocins produced by W. anomalus are safe and non-irritating. Thus, the results of this work can provide scientific evidence for the application of mycocins in the production of new antifungal alternatives.

Wickerhamomyces Yeast Killer Toxins' Medical Applications

Possible implications and applications of the yeast killer phenomenon in the fight against infectious diseases are reviewed, with particular reference to some wide-spectrum killer toxins (KTs) produced by Wickerhamomyces anomalus and other related species. A perspective on the applications of these KTs in the medical field is provided considering (1) a direct use of killer strains, in particular in the symbiotic control of arthropod-borne diseases; (2) a direct use of KTs as experimental therapeutic agents; (3) the production, through the idiotypic network, of immunological derivatives of KTs and their use as potential anti-infective therapeutics. Studies on immunological derivatives of KTs in the context of vaccine development are also described.

Antibiotic Activity of Wickerhamomyces anomalus Mycocins on Multidrug-Resistant Acinetobacter baumannii

To evaluate the susceptibility of multidrug-resistant Acinetobacter baumannii to mycocins produced by Wickerhamomyces anomalus and to verify the cytotoxicity of these compounds. Three culture supernatants of W. anomalus (WA40, WA45, and WA92), containing mycocins (WA40M1, WA45M2, and WA92M3), were tested on A. baumannii using broth microdilution methods, solid medium tests, and cytotoxicity tests in human erythrocytes and in Artemia saline Leach. W. anomalus was able to produce high antimicrobial mycocins, as even at high dilutions, they inhibited A. baumannii. In a solid medium, it was possible to observe the inhibition of A. baumannii, caused by the diffusion of mycocins between agar. Finally, the three supernatants were not cytotoxic when tested on human erythrocytes and Artemia salina. According to the evidence in this study, the mycocins of W. anomalus have been effective and could be used in the development of new antimicrobial substances.

Yeast Mycocins: a great potential for application in health

Mycocins have demonstrated inhibition of fungi, bacteria, parasites and viruses, in addition to being studied as epidemiological markers and in the development of vaccines. They are defined as extracellular proteins or glycoproteins with different activities, the main mechanism of action being the inhibition of β-glucan synthesis in the cell wall of sensitive strains. Given the resistance problems created by several microorganisms to agents commonly used in clinical practice, the discovery of new substances with this purpose becomes essential. Mycocins have potential as anti-microbials because they show minimal toxicity and do not present resistance.

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

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.