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Open Forum Infectious Diseases Jan 2023Fungal species have undergone and continue to undergo significant nomenclatural change, primarily due to the abandonment of dual species nomenclature in 2013 and the... (Review)
Review
Fungal species have undergone and continue to undergo significant nomenclatural change, primarily due to the abandonment of dual species nomenclature in 2013 and the widespread application of molecular technologies in taxonomy allowing correction of past classification errors. These have effected numerous name changes concerning medically important species, but by far the group causing most concern are the yeasts. Among common species, , , , , and have been changed to , , , , and , respectively. There are currently no guidelines for microbiology laboratories on implementing changes, and there is ongoing concern that clinicians will dismiss or misinterpret laboratory reports using unfamiliar species names. Here, we have outlined the rationale for name changes across the major groups of clinically important fungi and have provided practical recommendations for managing change.
PubMed: 36632423
DOI: 10.1093/ofid/ofac559 -
Brazilian Journal of Microbiology :... Jun 2023L-Asparaginase (L-ASNase) is a potent chemotherapeutic drug employed to treat leukemia and lymphoma. Currently, L-ASNases for therapeutic use are obtained from...
L-Asparaginase (L-ASNase) is a potent chemotherapeutic drug employed to treat leukemia and lymphoma. Currently, L-ASNases for therapeutic use are obtained from Escherichia coli and Dickeya chrysanthemi (Erwinia chrysanthemi). Despite their therapeutic potential, enzymes from bacteria are subject to inducing immune responses, resulting in a higher number of side effects. Eukaryote producers, such as fungi, may provide therapeutic alternatives through enzymes that induce relatively less toxicity and immune responses. Additional expected benefits from yeast-derived enzymes include higher activity and stability in physiological conditions. This work describes the new potential therapeutic candidate L-ASNase from the yeast Meyerozyma guilliermondii. A statistical approach (full factorial central composite design) was used to optimize L-ASNase production, considering L-asparagine and glucose concentration, pH of the medium, and cultivation time as independent factors. In addition, the crude enzymes were biochemically characterized, in terms of temperature and optimal pH, thermostability, pH stability, and associated glutaminase or urease activities. Our results showed that enzyme production increased after supplementing a pH 4.0 medium with 1.0% L-asparagine and 0.5% glucose during 75 h of cultivation. Under these optimized conditions, L-ASNase production reached 26.01 U mL, which is suitable for scale-up studies. The produced L-ASNase exhibits maximal activity at 37 °C and pH 7.0 and is highly stable under physiological conditions. In addition, M. guilliermondii L-ASNase has no associated glutaminase or urease activities, demonstrating its potential as a promising antineoplastic agent.
Topics: Asparaginase; Asparagine; Urease; Glutaminase; Antineoplastic Agents; Escherichia coli; Glucose
PubMed: 36917331
DOI: 10.1007/s42770-023-00939-x -
Brazilian Journal of Microbiology :... Dec 2022Meyerozyma guilliermondii has been accepted as a complex composed of Meyerozyma guilliermondii, Meyerozyma carpophila, and Meyerozyma caribbica. M. guilliermondii is a... (Review)
Review
Meyerozyma guilliermondii has been accepted as a complex composed of Meyerozyma guilliermondii, Meyerozyma carpophila, and Meyerozyma caribbica. M. guilliermondii is a saprophyte detected on human mucosa and skin. It can lead to serious infections in patients with risk factors like chemotherapy, immunodeficiency, gastrointestinal or cardiovascular surgery, and oncology disorders. Most deaths related to M. guilliermondii infections occur in individuals with malignancy. In recent decades, incidence of M. guilliermondii infections is increased. Sensitivity of this microorganism to conventional antifungals (e.g., amphotericin B, fluconazole, micafungin and anidulafungin) was reduced. Prophylactic and empirical uses of these drugs are linked to elevated minimal inhibitory concentrations (MICs) of M. guilliermondii. Drug resistance has concerned many researchers across the world. They are attempting to discover appropriate solution to combat this challenge. This study reviews the most important mechanisms of resistance to antifungals developed by in M. guilliermondii species complex.
Topics: Humans; Antifungal Agents; Drug Resistance, Fungal; Fluconazole; Amphotericin B; Microbial Sensitivity Tests
PubMed: 36306113
DOI: 10.1007/s42770-022-00813-2 -
Microorganisms Oct 2022Postharvest soft rot of kiwifruit has resulted in substantial market losses, yet there were few antagonistic yeasts reported to control the disease. This study screened...
Postharvest soft rot of kiwifruit has resulted in substantial market losses, yet there were few antagonistic yeasts reported to control the disease. This study screened 1113 yeast strains for potential antagonistic yeast to control soft rot of kiwifruit caused by Botryosphaeria dothidea and Diaporthe actinidiae, and strain 37 was selected to evaluate the control efficacy and mechanisms, which was identified as Meyerozyma guilliermondii via molecular biological identification. Our results showed that M. guilliermondii 37 effectively reduced pathogen spore germination rate to 28.52% and decay incidence of inoculated kiwifruit to 42.11% maximumly, whereas cell-free supernatant lacked antifungal activity, implying that M. guilliermondii 37 didn’t produce direct antifungal compounds against the two pathogens. In addition, M. guilliermondii 37 adhered tenaciously to the pathogens’ mycelium and colonized rapidly in kiwifruit flesh. Moreover, yeast strain 37 induced kiwifruit resistance by elevating the defense-related enzyme activity, increasing the antioxidant substances content, and suppressing the cell wall-degrading enzyme activity. Gene expression was consistent with the corresponding enzyme activity. Further postharvest yeast immersion treatment significantly reduced natural decay to 35.69% while maintaining soft-ripe quality. These results indicated that M. guilliermondii 37 might serve as a biocontrol agent against postharvest soft rot in kiwifruit.
PubMed: 36363735
DOI: 10.3390/microorganisms10112143 -
Pathogens (Basel, Switzerland) Jan 2021Coating seeds with bio-control agents is a potentially effective approach to reduce the usage of pesticides and fertilizers applied and protect the natural environment....
Coating seeds with bio-control agents is a potentially effective approach to reduce the usage of pesticides and fertilizers applied and protect the natural environment. This study evaluated the effect of seed coating with , strain INAT (MT731365), on seed germination, plant growth and photosynthesis, and plant resistance against , in durum wheat under controlled conditions. Compared to control plants, seed coating with promoted the wheat growth (shoot and roots length and biomass), and photosynthesis and transpiration traits (chlorophyll, ɸPSII, rates of photosynthesis and transpiration, etc.) together with higher nitrogen balance index (NBI) and lower flavonols and anthocyanins. At 21 days post infection with Fusarium, was found to reduce the disease incidence and the severity, with reduction rates reaching up to 31.2% and 30.4%, respectively, as well as to alleviate the disease damaging impact on photosynthesis and plant growth. This was associated with lower ABA, flavonols and anthocyanins, compared to infected control. A pivotal function of as an antagonist of and a growth promoter is discussed.
PubMed: 33429997
DOI: 10.3390/pathogens10010052 -
Journal of Fungi (Basel, Switzerland) Apr 2023Patulin (PAT), mainly produced by , is a potential threat to health. In recent years, PAT removal using antagonistic yeasts has become a hot research topic. , isolated...
Patulin (PAT), mainly produced by , is a potential threat to health. In recent years, PAT removal using antagonistic yeasts has become a hot research topic. , isolated by our group, produced antagonistic effects against the postharvest diseases of pears and could degrade PAT in vivo or in vitro. However, the molecular responses of over PAT exposure and its detoxification enzymes are not apparent. In this study, transcriptomics is used to unveil the molecular responses of on PAT exposure and the enzymes involved in PAT degradation. The functional enrichment of differentially expressed genes indicated that the molecular response mainly includes the up-regulated expression of genes related to resistance and drug-resistance, intracellular transport, growth and reproduction, transcription, DNA damage repair, antioxidant stress to avoid cell damage, and PAT detoxification genes such as short-chain dehydrogenase/reductases. This study elucidates the possible molecular responses and PAT detoxification mechanism of , which could be helpful to further accelerate the commercial application of antagonistic yeast toward mycotoxin decontamination.
PubMed: 37233249
DOI: 10.3390/jof9050538 -
Journal of Fungi (Basel, Switzerland) Aug 2023In this study, a halotolerant yeast that is capable of efficiently decolorizing and detoxifying azo dyes was isolated, identified and characterized for coping with the...
In this study, a halotolerant yeast that is capable of efficiently decolorizing and detoxifying azo dyes was isolated, identified and characterized for coping with the treatment of azo-dye-containing wastewaters. A characterization of the yeast, including the optimization of its metabolism and growth conditions, its detoxification effectiveness and the degradation pathway of the target azo dye, as well as a determination of the key activities of the enzyme, was performed. Finally, the possible halotolerance mechanisms of the yeast were proposed through a comparative transcriptome analysis. The results show that a halotolerant yeast, A4, which could decolorize various azo dyes, was isolated from a marine environment and was identified as . Its optimal conditions for dye decolorization were ≥1.0 g/L of sucrose, ≥0.2 g/L of (NH)SO, 0.06 g/L of yeast extract, pH 6.0, a temperature of 35 °C and a rotation speed of ≥160 rpm. The yeast, A4, degraded and detoxified ARB through a series of steps, relying on the key enzymes that might be involved in the degradation of azo dye and aromatic compounds. The halotolerance of the yeast, A4, was mainly related to the regulation of the cell wall components and the excessive uptake of Na/K and/or compatible organic solutes into the cells under different salinity conditions. The up-regulation of genes encoding Ca-ATPase and casein kinase II as well as the enrichment of KEGG pathways associated with proteasome and ribosome might also be responsible for its halotolerance.
PubMed: 37623622
DOI: 10.3390/jof9080851 -
Microbiology Spectrum Sep 2023Members of the species complex are able to cause superficial and life-threatening systemic infections with low susceptibility to azoles and echinocandins. We tested 130...
Members of the species complex are able to cause superficial and life-threatening systemic infections with low susceptibility to azoles and echinocandins. We tested 130 bloodstream complex isolates collected from eight Latin American medical centers over 18 years (period 1 = 2000-2008 and period 2 = 2009-2018) to investigate trends in species distribution and antifungal resistance. The isolates were identified by rDNA ITS region sequencing, and antifungal susceptibility tests were performed against fluconazole, voriconazole, anidulafungin, and amphotericin B using the CLSI microbroth method. (s.s.; = 116) was the most prevalent species, followed by ( = 12) and ( = 2). Based on rDNA ITS identification, three clades within were characterized (clade 1 = 94; clade 2 = 19; and clade 3 = 3). In the second period of study, we found a substantial increment in the isolation of (3.4% versus 13.8%; = 0.06) and clade 2 s.s. exhibiting lower susceptibility to one or more triazoles. IMPORTANCE Yeast-invasive infections play a relevant role in human health, and there is a concern with the emergence of non- pathogens causing disease worldwide. There is a lack of studies addressing the prevalence and antifungal susceptibility of different species within the complex that cause invasive infections. We evaluated 130 episodes of species complex candidemia documented in eight medical centers over 18 years. We detected the emergence of less common species within the complex causing candidemia and described a new clade of with limited susceptibility to triazoles. These results support the relevance of continued global surveillance efforts to early detect, characterize, and report emergent fungal pathogens exhibiting limited susceptibility to antifungals.
PubMed: 37698428
DOI: 10.1128/spectrum.05115-22 -
Microbiology Spectrum Dec 2022In recent decades, the incidence of infections has increased in immunocompromised patients. This multicenter study aimed to evaluate antifungal activities of 8...
In recent decades, the incidence of infections has increased in immunocompromised patients. This multicenter study aimed to evaluate antifungal activities of 8 antifungal agents against the species isolated from 10 university hospitals in Iran. During the period from Dec 2019 to Dec 2021, species were collected from clinical samples of patients. The isolates were identified by PCR restriction fragment length polymorphism and sequencing methods. The antifungal susceptibility tests of each isolate to eight antifungal agents were performed according to the microdilution CLSI M27, M59, and M60 standard methods. A total of 598 strains were isolated from clinical samples. The most commonly isolated species was C. albicans, followed by C. glabrata, C. parapsilosis, Debaryomyces hansenii (Candida famata), C. tropicalis, (Candida krusei), C. orthopsilosis, Meyerozyma guilliermondii (Candida guilliermondii), Kluyveromyces marxianus (Candida kefyr), and Clavispora lusitaniae (Candida lusitaniae). MIC values in all species were as follows: 0.25 μg/mL for caspofungin and voriconazole; 0.5 μg/mL for amphotericin B and isavuconazole; 2 μg/mL for itraconazole, luliconazole, and posaconazole; and 16 μg/mL for fluconazole. Although 30/285 C. albicans, 15/31 3/12 , 67/125 C. glabrata, 5/15 , 6/60 C. parapsilosis, and 5/23 C. tropicalis isolates were multiazole resistant with resistance to 2 to 4 azoles, pan-azole resistance was not observed. According to our data, Candida albicans and C. glabrata were the most frequent species isolated from clinical samples in Iran. Caspofungin and voriconazole, with lower MIC values, are the most effective than other antifungal agents for the treatment of infections in this region. species cause severe invasive infections of the heart, brain, eyes, bones, and other parts of the body. Knowledge of regional distributions of causative agents and their antifungal susceptibility patterns can help to monitor resistance to antifungal agents of various species and support local and national surveillance programs. In the present study, C. albicans and C. glabrata were the most frequently isolated species from clinical samples in Iran. Increasing rates of non- isolates from the Iranian population should be looked at as alarming due to various levels of intrinsic MIC values or resistance to various antifungal drugs. Caspofungin and voriconazole are recommended over fluconazole for the treatment of infections in the study region. However, amphotericin B and isavuconazole are also active against the most common species isolated from patients. Pan azole-resistant species were not observed in the present study.
Topics: Humans; Amphotericin B; Antifungal Agents; Azoles; Candida; Candida albicans; Candida glabrata; Candidiasis; Caspofungin; Drug Resistance, Fungal; Fluconazole; Iran; Microbial Sensitivity Tests; Tertiary Care Centers; Voriconazole
PubMed: 36445122
DOI: 10.1128/spectrum.02453-22 -
G3 (Bethesda, Md.) Mar 2018Yeasts of the species complex are widespread in nature and can be isolated from a variety of sources, from the environment to arthropods to hospital patients. To date,...
Yeasts of the species complex are widespread in nature and can be isolated from a variety of sources, from the environment to arthropods to hospital patients. To date, the species complex comprises the thoroughly studied and versatile , the hard to distinguish , and Here we report the whole genome sequencing and assembly of four isolates, identified with the most recent molecular techniques, derived from four Diptera species. The four novel assemblies present reduced fragmentation and comparable metrics (genome size, gene content) to the available genomes belonging to the species complex. We performed a phylogenomic analysis comprising all known members of the species complex, to investigate evolutionary relationships within this clade. Our results show a compact phylogenetic structure for the complex and indicate the presence of a sizable core set of genes. Furthermore, , despite a broad literature on the difficulties of discerning it from , seems to be more closely related to Finally, we believe that there is evidence for considering these four genomes to be the first published for the species Raw reads and assembled contigs have been made public to further the study of these organisms.
Topics: Ascomycota; Computational Biology; Genome, Fungal; Genomics; Molecular Sequence Annotation; Phylogeny
PubMed: 29311113
DOI: 10.1534/g3.117.300316