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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 ß-glucanases, glycoproteins known to act on microorganism cell walls. However, it is important to note that this supernatant may contain other compounds as well. ß-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 ß-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.

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Trichosporonosis corresponds to a systemic fungal disease that leads to high mortality rates and is frequently associated with medical devices. It affects immunosuppressed patients in particular and is strongly linked to acquired human immunodeficiency, organ and tissue transplants, and malignant hematologic diseases such as leukemia and lymphomas. Trichosporon infections have been increasingly reported worldwide; however, little information is available either about their characteristics or the causative microorganism. Thus, the aims of the present study were: to investigate 59 yeasts of the genus Trichosporon by verifying the biofilm formation capacity of isolates; to analyze the susceptibility patterns of planktonic cells against the antifungals fluconazole, itraconazole, amphotericin-B, voriconazole, and caspofungin by comparing European Committee for Antimicrobial Susceptibility Testing (EUCAST) broth microdilution technique with the commercial method Etest; and to assess the susceptibility patterns of biofilm cells (sessile) against the same antifungals through broth microdilution. The ability to form biofilm on the surface of polystyrene plates was noted for all isolates, and 54.3% of samples were considered strong producers. Comparison between the antifungal susceptibility techniques evidenced that Etest showed higher and discordant minimum inhibitory concentrations (MICs) from those obtained by the microdilution method, especially for fluconazole, itraconazole, and caspofungin. Considering the susceptibility of biofilms, most species had high MIC50 and MIC90 against the tested antifungals, showing 4-to-66-fold higher concentrations for amphotericin B and 2-to-33-fold greater concentrations for caspofungin. These results highlight the importance of further studies with Trichosporon spp. for comparison between laboratory findings and in vivo response, considering both the susceptibility tests and the behavior of biofilm cells against drugs.

This study investigated 59 isolates of the medically important yeast Trichosporon in relation to their ability to form biofilms and the susceptibility of biofilms to antifungal agents. All isolates were able to produce biofilms and biofilms showed lower antifungal susceptibility.

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New alternatives have been under study as treatment due to the problem of multidrug-resistant bacteria. Among them, Wickerhamomyces anomalus mycocins have shown a great potential against several microorganisms since they have high antimicrobial activity, as well as they can be used as fast available nutrients and stand several extreme conditions. In this way, Klebsiella pneumoniae carbapenemases inhibition by mycocins produced by W. anomalus is important. Microdilution assays were carried out to evaluate strains inhibition in liquid medium and the test in solid medium were carried out. Toxicity was evaluated by both hemolysis and Artemia salina Leach tests. W. anomalus supernatant showed 2.36 U/mg ß-glucanases activity, and antimicrobial activity was evidenced in 100% Klebsiella pneumoniae carbapenemase strains up to 0.12 U/mg concentration. Besides, there was low toxicity in hemolysis and Artemia salina Leach tests. It is suggested that W. anomalus mycocins may be an alternative to develop new antimicrobial substances.

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Trichosporon spp. are widely distributed in the nature, comprising species that inhabit different ecological niches and can be found in the water, soil, and body surface of animals and humans. Such microorganisms have been classically associated with superficial infections; however, in the last decades, they have also been related to disseminated infections in immunocompromised patients, behaving as opportunistic agents, which demands rapid and accurate species identification for efficient therapy. Concordance level between the traditional phenotypic method and the molecular technique (gold standard) in the identification of all 59 Trichosporon samples was 59.3%. Identification concordance between MALDI-TOF spectrometry and the molecular technique was 71.2%. No isolate of environmental origin was identifiable by MALDI-TOF mass spectrometry (MS), and 100% of such environmental isolates were discordant for IGS region sequencing and phenotypic characterization. Both comparisons evidenced greatest concordance in the identification of T. asahii. The species T. debeurmannianum, T. dermatis, T. venhuisii and T. insectorum were not properly identified by both MALDI-TOF MS and the phenotypic technique. MALDI-TOF MS, in particular, seems to be appropriate to investigate yeasts of the genus Trichosporon; however, database updates are still necessary, especially for species that are not common in the clinical routine. With the aim of helping understand the aspects involved in early and accurate diagnosis of infections caused by this opportunistic agent, the present study compared the phenotypic, molecular (IGS region) and mass-spectrometry (MALDI-TOF) identification of 59 yeasts of the genus Trichosporon which had clinical and environmental origin and were kept in a mycology collection.

The present study compared the phenotypic, genotypic, and mass-spectrometry (MALDI-TOF) identification of 59 yeasts of the genus Trichosporon. MALDI-TOF MS, in particular, seems to be appropriate to investigate this yeasts when compared to a molecular technique (gold standard).

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This study characterized and related yeasts of the genus Candida isolated from vaginal mucous membranes of women with lesions caused by high-risk HPV for cervical cancer. Forty-two women treated at the Lower Genital Tract Pathology Clinic of the University of São Paulo Medical School Hospital of Clinics were examined, with 30 high-grade (G1) uterine lesions with a mean age of 36.5 years ± 11. 1 and 12 with low grade (G2) uterine lesions with a mean age of 34.7 years ± 15.5. Clinical conditions and laboratory data on HPV were collected from patients' medical records; the socio-demographic data obtained from an appropriate questionnaire. For the study of association between the variables, Odds Ratio analysis was used from the STATA 13.1 program. Patients G1 had a higher prevalence for diabetes and the results indicated 27% prevalence of Candida spp. in vaginal mucosa, in G2 this was 33% in vaginal mucosa. Among the species found in vaginal mucosa of patients, Candida albicans was the most isolated with 88%, followed by C. tropicalis (8%) and C. glabrata (4%). The strains of C. albicans isolated from mucosa presented sensitivity to all antifungal agents tested, unlike the C. tropicalis strain isolated in G2 in vaginal mucosa, which presented a resistance profile to fluconazole. Thus, monitoring and supervision through clinical and laboratory testing of HPV patients is important, reinforcing the need for care, treatment and prevention of HPV-related infections and Candida spp.

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This is the first report of the yeast Apiotrichum veenhuisii (formerly Trichosporon veenhuisii) causing disease in humans; its virulence and in vitro behavior against antifungals were also studied. The sample was isolated from biopsy fragments of disseminated lesions on the skin of a pediatric patient with acute myeloid leukemia. The studied virulence factors evidenced that the strain tested negative for secretion of the enzymes proteinase, phospholipase, and hemolysin. The isolate was characterized as low biofilm producer. Except for amphotericin B and voriconazole, the sample presented high minimum inhibitory concentration values against azole and echinocandins.

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INTRODUCTION: Acrylic resins are used in the preparation of facial prostheses and may be colonized by fungi. Here, we verified the antifungal efficacy of this material after surface treatment using poly (diallyldimethylammonium chloride). METHODS: Acrylic resin specimens with and without surface treatment were subjected to tests for fungistatic and fungicidal activities. Standard strains of Candida albicans and Aspergillus niger were used. RESULTS: After surface treatment, the fungistatic and fungicidal efficacies of the resins against C. albicans and fungistatic action against A. niger were verified. CONCLUSIONS: The surface treatment was a determinant of the antifungal activity of the material.

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Objective: To evaluate the inclusion capacity and bactericidal efficiency of diallyl dimethyl ammonium chloride (PDADMAC) diluted in tetrahydrofuran (THF) upon inclusion in the medical grade silicone polymer structure. Material and Methods: It was diluted the PDADMAC in THF at the concentration of 4wt%. It was included in the silicon paste during its vulcanization process. The contact angle measurements were performed to evaluate whether the biocide inclusion into the silicon paste was successful. All samples were sterilized with gamma radiation at 25KGy-dosage prior to the microbiological tests. Microbiological testing strictly followed the Antibacterial products - Test for antibacterial activity and efficacy JIS Z 2801: 201010 and the used of specific bacteria, as Staphylococcus aureus ATCC 6538P and Escherichia coli ATCC 8739. Results: The results showed that PDADMAC, when dissolved in THF at 4wt%, displayed good incorporation in medical silicone and a broad-spectrum antibacterial response. The results of the tests using Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P showed that the silicone with no biocide addition did not present antibacterial activity. In contrast, the experimental group plus 2 mL of PDADMAC would have an ideal antibacterial response. Conclusion: Medical grade silicone can be used as a material with antibacterial properties, since it has been able to keep PDADMAC compound attached to its structure, thus acquiring antimicrobial property.

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Abstract INTRODUCTION: Acrylic resins are used in the preparation of facial prostheses and may be colonized by fungi. Here, we verified the antifungal efficacy of this material after surface treatment using poly (diallyldimethylammonium chloride). METHODS: Acrylic resin specimens with and without surface treatment were subjected to tests for fungistatic and fungicidal activities. Standard strains of Candida albicans and Aspergillus niger were used. RESULTS: After surface treatment, the fungistatic and fungicidal efficacies of the resins against C. albicans and fungistatic action against A. niger were verified. CONCLUSIONS: The surface treatment was a determinant of the antifungal activity of the material.

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