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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 -
Frontiers in Microbiology 2023Extremely salt-tolerant microorganisms play an important role in the development of functional metabolites or drug molecules.
INTRODUCTION
Extremely salt-tolerant microorganisms play an important role in the development of functional metabolites or drug molecules.
METHODS
In this work, the salt stress perception and metabolic regulation network of a marine probiotic GXDK6 were investigated using integrative omics technology.
RESULTS
Results indicated that GXDK6 could accept the salt stress signals from signal transduction proteins (e.g., phosphorelay intermediate protein YPD1), thereby contributing to regulating the differential expression of its relevant genes (e.g., , ) and proteins (e.g., catalase, superoxide dismutase) in response to salt stress, and increasing the salt-tolerant viability of GXDK6. Omics data also suggested that the transcription (e.g., ), translation (e.g., ), and protein synthesis and processing (e.g., inner membrane protein OXA1) of upregulated RNAs may contribute to increasing the salt-tolerant survivability of GXDK6 by improving protein transport activity (e.g., Small nuclear ribonucleoprotein Sm D2), anti-apoptotic ability (e.g., 54S ribosomal protein L1), and antioxidant activity (e.g., superoxide dismutase). Moreover, up to 65.9% of the differentially expressed genes/proteins could stimulate GXDK6 to biosynthesize many salt tolerant-related metabolites (e.g., β-alanine, D-mannose) and drug molecules (e.g., deoxyspergualin, calcitriol), and were involved in the metabolic regulation of GXDK6 under high NaCl stress.
DISCUSSION
This study provided new insights into the exploration of novel functional products and/or drugs from extremely salt-tolerant microorganisms.Graphical Abstract.
PubMed: 37529325
DOI: 10.3389/fmicb.2023.1193352 -
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 de Mycologie Medicale Dec 2017Meyerozyma (Pichia) guilliermondii exists in human skin and mucosal surface microflora. It can cause severe fungal infections like candidemia, which is an opportunistic...
Meyerozyma (Pichia) guilliermondii exists in human skin and mucosal surface microflora. It can cause severe fungal infections like candidemia, which is an opportunistic pathogen. One hundred and forty-one M. guilliermondii isolates, consisting of 122 blood culture isolates, belonging to 126 patients; 13 total parenteral nutrition solution isolates; and two rectal swab isolates were identified according to carbohydrate assimilation reactions in a university hospital in Turkey between January 2006 and December 2015. Following Candida albicans (34.0%) and C. parapsilosis (21.2%), the third yeast species most commonly isolated from blood cultures in the Farabi Hospital was M. guilliermondii (20.6%). The patients were hospitalised in 27 different departments. A total of 50% of the patients were in pediatric departments, 49.2% were in intensive care units, and 17.2% were in haematology-oncology departments. Molecular identification of the isolates was performed using DNA sequence analysis of ribosomal ITS gene regions and IGS amplification-AluI fingerprinting (IGSAF). With molecular identification, 140 isolates were identified as M. guilliermondii and one isolate was identified as Candida membranifaciens. It was observed that the ITS1 region specifically helps in identifying these species. It was demonstrated that biochemical and molecular methods were 99.3% consistent in identifying M. guilliermondii. The Wild-Type (WT) Minimum Inhibitory Concentrations (MICs) distribution of fluconazole, voriconazole, itraconazole, and flucytosine were determined using the Sensititre YeastOne YO2V system after 24h of incubation. One M. guilliermondii strain was determined to be non-WT for fluconazole, voriconazole, itraconazole and flucytosine. In total, three M. guilliermondii strains, for fluconazole, were determined to be non-WT in this study.
Topics: Antifungal Agents; Blood Culture; Candida; Candidiasis; Drug Resistance, Fungal; Epidemiological Monitoring; Fluconazole; Hospitalization; Hospitals, University; Humans; Intensive Care Units; Itraconazole; Microbial Sensitivity Tests; Mycoses; Pichia; Surveys and Questionnaires; Time Factors; Turkey; Voriconazole
PubMed: 28843335
DOI: 10.1016/j.mycmed.2017.07.007 -
Food Chemistry Aug 2023The intracellular enzymes of antagonistic yeast are effective in controlling patulin (PAT) contamination. However, countless enzymes that have been revealed remain...
The intracellular enzymes of antagonistic yeast are effective in controlling patulin (PAT) contamination. However, countless enzymes that have been revealed remain functionally uncharacterized. The study built on previous transcriptomic data obtained by our research group to amplify and express a gene encoding a short-chain dehydrogenase/reductase (SDR) in Meyerozyma guilliermondii. Overexpression of SDR increased the tolerance of M. guilliermondii to PAT and the ability to degrade PAT of the intracellular enzymes. Furthermore, MgSDR-overexpressed M. guilliermondii showed higher PAT degradation in juices (apple and peach) and controlled the blue mold of pears at 20 °C and 4 °C while significantly reduced the content of PAT and the biomass of Penicillium expansum in decayed tissues than wild-type M. guilliermondii. This study provides theoretical references for the subsequent heterologous expression, formulation, and application of the SDR protein from M. guilliermondii and contributes to elucidating the PAT degradation mechanism of antagonistic yeasts.
Topics: Pyrus; Patulin; Malus; Fruit; Yeasts; Penicillium
PubMed: 36913869
DOI: 10.1016/j.foodchem.2023.135785 -
International Journal of Food... Jan 2021Apple ring rot, caused by Botryosphaeria dothidea, is one of the important diseases in China. This pathogen infects branches and fruit and also results in fruit decay...
Apple ring rot, caused by Botryosphaeria dothidea, is one of the important diseases in China. This pathogen infects branches and fruit and also results in fruit decay during storage. Biocontrol agents have been proposed to reduce apple decays during storage and are considered as a promising alternative strategy to traditional chemical treatment. In this study, Meyerozyma guilliermondii Y-1, isolated from healthy grape fruit, was firstly evaluated for its biocontrol efficiency against B. dothidea in postharvest apple fruit, and the possible mechanisms were investigated. The results revealed that M. guilliermondii Y-1 treatment effectively reduced apple ring rot caused by B. dothidea in vivo. The disease incidence and lesion diameter were reduced by 32.22% and 57.51% compared with those of control fruit. Furthermore, the use of filtrate and autoclaved culture of M. guilliermondii Y-1 also showed a certain degree of control efficiency against fruit ring rot. M. guilliermondii Y-1 significantly inhibited the mycelial growth and spore generation of B. dothidea in vitro and exhibited an obvious ability to colonize in apple fruit wounds and surface at 25 °C or 4 °C. In addition, M. guilliermondii Y-1 treatment significantly enhanced the activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonialyase (PAL), and polyphenoloxidase (PPO), promoted the total phenolics content, and alleviated lipid peroxidation in apple fruit. As expected, we found that the expression of four pathogenesis-related proteins genes (MdPR1, MdPR5, MdGLU, and MdCHI) was remarkably increased by M. guilliermondii Y-1 treatment. Our data together suggest that M. guilliermondii Y-1 is a potential biocontrol agent against B. dothidea postharvest infection in apple fruit, partially through inhibiting mycelial growth and spore germination of B. dothidea, competing for space and nutrient with pathogen, and inducing resistance in apple fruit by stimulating a series of defense responses.
Topics: Antibiosis; Ascomycota; China; Food Microbiology; Malus; Saccharomycetales
PubMed: 33221041
DOI: 10.1016/j.ijfoodmicro.2020.108957 -
Mycoses Mar 2024Meyerozyma guilliermondii is a yeast species responsible for invasive fungal infections. It has high minimum inhibitory concentrations (MICs) to echinocandins, the...
BACKGROUND
Meyerozyma guilliermondii is a yeast species responsible for invasive fungal infections. It has high minimum inhibitory concentrations (MICs) to echinocandins, the first-line treatment of candidemia. In this context, azole antifungal agents are frequently used. However, in recent years, a number of azole-resistant strains have been described. Their mechanisms of resistance are currently poorly studied.
OBJECTIVE
The aim of this study was consequently to understand the mechanisms of azole resistance in several clinical isolates of M. guilliermondii.
METHODS
Ten isolates of M. guilliermondii and the ATCC 6260 reference strain were studied. MICs of azoles were determined first. Whole genome sequencing of the isolates was then carried out and the mutations identified in ERG11 were expressed in a CTG clade yeast model (C. lusitaniae). RNA expression of ERG11, MDR1 and CDR1 was evaluated by quantitative PCR. A phylogenic analysis was developed and performed on M. guilliermondii isolates. Lastly, in vitro experiments on fitness cost and virulence were carried out.
RESULTS
Of the ten isolates tested, three showed pan-azole resistance. A combination of F126L and L505F mutations in Erg11 was highlighted in these three isolates. Interestingly, a combination of these two mutations was necessary to confer azole resistance. An overexpression of the Cdr1 efflux pump was also evidenced in one strain. Moreover, the three pan-azole-resistant isolates were shown to be genetically related and not associated with a fitness cost or a lower virulence, suggesting a possible clonal transmission.
CONCLUSION
In conclusion, this study identified an original combination of ERG11 mutations responsible for pan-azole-resistance in M. guilliermondii. Moreover, we proposed a new MLST analysis for M. guilliermondii that identified possible clonal transmission of pan-azole-resistant strains. Future studies are needed to investigate the distribution of this clone in hospital environment and should lead to the reconsideration of the treatment for this species.
Topics: Humans; Azoles; Multilocus Sequence Typing; Drug Resistance, Fungal; Antifungal Agents; Mutation; Microbial Sensitivity Tests; Fluconazole; Saccharomycetales
PubMed: 38429226
DOI: 10.1111/myc.13704 -
Journal of Agricultural and Food... Jun 2023Production of 2-phenylethanol (2-PE) via is well-established. However, co-culture with other microbes in combination with product recovery (ISPR) yields improved...
Production of 2-phenylethanol (2-PE) via is well-established. However, co-culture with other microbes in combination with product recovery (ISPR) yields improved selectivity and volumetric productivity. Fermentation of (MUCL 53775) with direct inclusion of absorptive polymer Hytrel3548 achieved ISPR, but accumulation of the byproduct phenylethyl acetate (PEA) was strongly favored. Co-culture of (MUCL 53775) with (MUCL 28072) with ISPR limited PEA production, thereby improving the 2-PE selectivity from 13 to 90%, compared to a pure culture of (MUCL 53775) under similar conditions. This improved the volumetric productivity by 85% compared to 2-PE ISPR with a pure culture of . This is the first report of co-culture in a two-phase fermentation for 2-PE bioproduction and demonstrates that interactions between co-culture and ISPR techniques can modulate bioproduction between 2-PE and byproduct PEA, and this technique will be explored for other strain combinations and for other high-value molecules of interest.
Topics: Phenylethyl Alcohol; Coculture Techniques; Kluyveromyces; Fermentation; Acetates
PubMed: 37272733
DOI: 10.1021/acs.jafc.3c01356 -
Biochimica Et Biophysica Acta. General... Aug 2022Six different yeasts were used to study their metabolism of glucose and xylose, and mainly their capacity to produce ethanol and xylitol. The strains used were Candida...
Six different yeasts were used to study their metabolism of glucose and xylose, and mainly their capacity to produce ethanol and xylitol. The strains used were Candida guilliermondii, Debaryomyces hansenii, Saccharomyces cerevisiae, Kluyveromyces marxianus, Meyerozyma guilliermondii and Clavispora lusitaniae, four isolated from a rural mezcal fermentation facility. All of them produced ethanol when the substrate was glucose. When incubated in a medium containing xylose instead of glucose, only K. marxianus and M. guilliermondii were able to produce ethanol from xylose. On the other hand, all of them could produce some xylitol from xylose, but the most active in this regard were K. marxianus, M. guilliermondii, C. lusitaniae, and C. guilliermondii with the highest amount of xylitol produced. The capacity of all strains to take up glucose and xylose was also studied. Xylose, in different degrees, produced a redox imbalance in all yeasts. Respiration capacity was also studied with glucose or xylose, where C. guilliermondii, D. hansenii, K. marxianus and M. guilliermondii showed higher cyanide resistant respiration when grown in xylose. Neither xylose transport nor xylitol production were enhanced by an acidic environment (pH 4), which can be interpreted as the absence of a proton/sugar symporter mechanism for xylose transport, except for C. lusitaniae. The effects produced by xylose and their magnitude depend on the background of the studied yeast and the conditions in which these are studied.
Topics: Ethanol; Glucose; Saccharomyces cerevisiae; Saccharomycetales; Xylitol; Xylose
PubMed: 35461922
DOI: 10.1016/j.bbagen.2022.130154 -
The Science of the Total Environment Dec 2022The widespread use of polyethylene (PE) causes a large amount of indigestible plastic waste. Waxworms (the larvae of Plodia interpunctella) can eat PE, but the...
The widespread use of polyethylene (PE) causes a large amount of indigestible plastic waste. Waxworms (the larvae of Plodia interpunctella) can eat PE, but the degradation principle of PE under the action of intestinal microorganisms is still unclear, especially the insufficient research on key degradable PE strains. In this study, we fed waxworms with PE. Two strains with high PE degradation efficiency were isolated and purified, and the effects of single and microbial consortia on PE degradation were evaluated by water contact angle (WCA), FTIR, GC-MS, SEM and RT-qPCR. The results showed that Meyerozyma guilliermondii ZJC1 (MgZJC1) and Serratia marcescens ZJC2 (SmZJC2) could degrade PE. However, the degradation efficiency of the microbial consortium was higher, and the weight loss rate of PE was 15.87 %. In addition, the PE degradation products of MgZJC1 were CHO, CHNO, CHO and CHO, and the PE degradation products of SmZJC2 were CHO, CHNO and CHO. The PE degradation products of the microbial consortium were CH, CHO, CH, CH, CH, CH and CH. RT-qPCR results showed that SmZJC2 promoted PE degradation by upregulating the expression of multiple genes, such as multicopper oxidase genes (PiSm-CueO). MgZJC1 responded to carbon deficiency by upregulating the expression of multiple genes, such as key enzyme genes in the tricarboxylic acid (TCA) cycle. This study can be used to develop an efficient microbial consortium for PE degradation and provide a basis for the reuse of PE waste. It can also provide a research basis for the joint degradation of PE by microbial consortia composed of bacteria and fungi.
Topics: Animals; Biodegradation, Environmental; Carbon; Larva; Lepidoptera; Oxidoreductases; Plastics; Polyethylene; Serratia marcescens; Tricarboxylic Acids
PubMed: 36089048
DOI: 10.1016/j.scitotenv.2022.158604