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Antimicrobial Agents and Chemotherapy Oct 2021Susceptibility testing is an important tool in the clinical setting; its utility is based on the availability of categorical endpoints, breakpoints (BPs), or...
Etest ECVs/ECOFFs for Detection of Resistance in Prevalent and Three Nonprevalent spp. to Triazoles and Amphotericin B and Aspergillus spp. to Caspofungin: Further Assessment of Modal Variability.
Susceptibility testing is an important tool in the clinical setting; its utility is based on the availability of categorical endpoints, breakpoints (BPs), or epidemiological cutoff values (ECVs/ECOFFs). CLSI and EUCAST have developed antifungal susceptibility testing, BPs, and ECVs for some fungal species. Although the concentration gradient strip bioMérieux Etest is useful for routine testing in the clinical laboratory, ECVs are not available for all agent/species; the lack of clinical data precludes development of BPs. We reevaluated and consolidated Etest data points from three previous studies and included new data. We defined ECOFFinder Etest ECVs for three sets of species-agent combinations: fluconazole, posaconazole, and voriconazole and 9 spp.; amphotericin B and 3 nonprevalent spp.; and caspofungin and 4 Aspergillus spp. The total of Etest MICs from 23 laboratories (Europe, the Americas, and South Africa) included (antifungal agent dependent): 17,242 Candida albicans, 244 C. dubliniensis, 5,129 C. glabrata species complex (SC), 275 C. guilliermondii (Meyerozyma guilliermondii), 1,133 C. krusei (), 933 C. kefyr (Kluyveromyces marxianus), 519 C. lusitaniae (Clavispora lusitaniae), 2,947 C. parapsilosis SC, 2,214 C. tropicalis, 3,212 Aspergillus fumigatus, 232 A. flavus, 181 A. niger, and 267 A. terreus SC isolates. Triazole MICs for 66 confirmed non-wild-type (non-WT) isolates were available ( point mutations). Distributions fulfilling CLSI ECV criteria were pooled, and ECOFFinder Etest ECVs were established for triazoles (9 spp.), amphotericin B (3 less-prevalent spp.), and caspofungin (4 Aspergillus spp.). Etest fluconazole ECVs could be good detectors of non-WT isolates (59/61 non-WT, 4 of 6 species).
Topics: Amphotericin B; Antifungal Agents; Aspergillus; Candida; Caspofungin; Disk Diffusion Antimicrobial Tests; Drug Resistance, Fungal; Kluyveromyces; Microbial Sensitivity Tests; Pichia; Saccharomycetales; Triazoles
PubMed: 34370582
DOI: 10.1128/AAC.01093-21 -
Molecules (Basel, Switzerland) Jan 2021This study aimed to identify the volatile compounds in the fermented and dried cocoa beans conducted with three distinct inoculants of yeast species due to their high...
This study aimed to identify the volatile compounds in the fermented and dried cocoa beans conducted with three distinct inoculants of yeast species due to their high fermentative capacity: , , the mixture in equal proportions 1:1 of both species, and a control fermentation (with no inoculum application). Three starter cultures of yeasts, previously isolated and identified in cocoa fermentation in the municipality of Tomé-Açu, Pará state, Brazil. The seeds with pulp were removed manually and placed in wooden boxes for the fermentation process that lasted from 6 to 7 days. On the last day of fermentation, the almonds were packaged properly and placed to dry (36 °C), followed by preparation for the analysis of volatile compounds by GC-MS technique. In addition to the control fermentation, a high capacity for the formation of desirable compounds in chocolate by the inoculants with was observed, which was confirmed through multivariate analyses, classifying these almonds with the highest content of aldehydes, esters, ketones and alcohols and low concentration of off-flavours. We conclude that the addition of mixed culture starter can be an excellent alternative for cocoa producers, suggesting obtaining cocoa beans with desirable characteristics for chocolate production, as well as creating a product identity for the producing region.
Topics: Cacao; Chocolate; Fermentation; Food Industry; Pichia; Saccharomyces cerevisiae; Seeds; Volatile Organic Compounds
PubMed: 33440885
DOI: 10.3390/molecules26020344 -
Foods (Basel, Switzerland) Oct 2023Currently, non- yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation...
Currently, non- yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation of non- yeasts was addressed by their isolation during spontaneous fermentations of organic Verdejo grapes, obtaining a total of 484 isolates, of which 11% were identified by molecular techniques as non- yeasts. Fermentative isolates belonging to the species , , , , , and were analysed. Significant differences were found in the yeast populations established at the different fermentation stages. Interestingly, stood up as a widely distributed species in vineyards, vintages, and fermentation stages. Several of the strains studied stood out for their biotechnological potential in the production of Verdejo wine, showing the presence of relevant enzymatic activity for the release of varietal aromas and the technological improvement of the winemaking process. Three enzymatic activities were found in an important number of isolates, β-glucosidase, protease, and β-lyase, implicated in the positive aromatic impact on this style of white wine. In that sense, all the isolates of presented those activities. isolates were highlighted for their significant β-lyase activity. In addition, was outlined because of its potential to achieve an elevated fermenting power, as well as the lack of lag phase. The results obtained highlight the importance of maintaining the microbial diversity that contributes to the production of wines with unique and distinctive characteristics of the production region.
PubMed: 37835297
DOI: 10.3390/foods12193644 -
Journal of Insect Science (Online) May 2024The black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae), is commonly used for organic waste recycling and animal feed production. However, the often...
The black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae), is commonly used for organic waste recycling and animal feed production. However, the often inadequate nutrients in organic waste necessitate nutritional enhancement of black soldier fly larvae, e.g., by fungal supplementation of its diet. We investigated the amino acid composition of two fungi, Candida tropicalis (Castell.) Berkhout (Saccharomycetales: Saccharomycetaceae) and Pichia kudriavzevii Boidin, Pignal & Besson (Saccharomycetales: Pichiaceae), from the black soldier fly gut, and commercial baker's yeast, Saccharomyces cerevisiae Meyen ex E.C. Hansen (Saccharomycetales: Saccharomycetaceae), and their effects on larval growth and hemolymph metabolites in fifth-instar black soldier fly larvae. Liquid chromatography-mass spectrometry was used to study the effect of fungal metabolites on black soldier fly larval metabolism. Amino acid analysis revealed significant variation among the fungi. Fungal supplementation led to increased larval body mass and differential metabolite accumulation. The three fungal species caused distinct metabolic changes, with each over-accumulating and down-accumulating various metabolites. We identified significant alteration of histidine metabolism, aminoacyl-tRNA biosynthesis, and glycerophospholipid metabolism in BSF larvae treated with C. tropicalis. Treatment with P. kudriavzevii affected histidine metabolism and citrate cycle metabolites, while both P. kudriavzevii and S. cerevisiae treatments impacted tyrosine metabolism. Treatment with S. cerevisiae resulted in down-accumulation of metabolites related to glycine, serine, and threonine metabolism. This study suggests that adding fungi to the larval diet significantly affects black soldier fly larval metabolomics. Further research is needed to understand how individual amino acids and their metabolites contributed by fungi affect black soldier fly larval physiology, growth, and development, to elucidate the interaction between fungal nutrients and black soldier fly physiology.
Topics: Animals; Larva; Diptera; Hemolymph; Pichia; Saccharomyces cerevisiae; Amino Acids; Diet; Saccharomycetales; Animal Feed; Candida
PubMed: 38713543
DOI: 10.1093/jisesa/ieae050 -
Microorganisms Sep 2022Non-conventional yeasts (NCY) (i.e., non-) may be used as alternative starters to promote biodiversity and quality of fermented foods and beverages (e.g., wine, beer,...
BACKGROUND
Non-conventional yeasts (NCY) (i.e., non-) may be used as alternative starters to promote biodiversity and quality of fermented foods and beverages (e.g., wine, beer, bakery products).
METHODS
A total of 32 wine-associated yeasts (Campania region, Italy) were genetically identified and screened for decarboxylase activity and leavening ability. The best selected strains were used to study the leavening kinetics in model doughs (MDs). A commercial strain of was used as the control. The volatile organic profiles of the inoculated MDs were analyzed by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS).
RESULTS
Most of strains belonged to the NCY species , , , , and , while a few strains were . Most strains of lacked decarboxylase activity and showed a high leaving activity after 24 h of incubation that was comparable to the strains. The selected strains generated a different flavor profile of the doughs compared to the strains. In particular, NCY reduced the fraction of aldehydes that were potentially involved in oxidative phenomena.
CONCLUSIONS
The use of NCY could be advantageous in the bakery industry, as they can provide greater diversity than -based products, and may be useful in reducing and avoiding yeast intolerance.
PubMed: 36144451
DOI: 10.3390/microorganisms10091849 -
Foods (Basel, Switzerland) Aug 2023The responses of various microbial populations to modifications in the physicochemical properties of a food matrix, as well as interactions between these populations...
The responses of various microbial populations to modifications in the physicochemical properties of a food matrix, as well as interactions between these populations already present, are the main factors that shape microbial dynamics in that matrix. This work focused on the study of microbial dynamics during labneh Ambaris production, a traditional Lebanese concentrated fermented goat milk made in jars during 3 months. This was assessed in two earthenware jars at a production facility. DNA metabarcoding of the ITS2 region as well as the V3-V4 region of the 16S rRNA gene was used to characterize the fungal and bacterial communities, respectively. Viable bacterial isolates were also identified by Sanger sequencing of the V1-V4 region of the 16S rRNA gene. Our results showed that the dominant microorganisms identified within labneh Ambaris (, , , , and sp.) settle early in the product and remain until the end of maturation with varying abundances throughout fermentation. Microbial counts increased during early fermentation stage, and remained stable during mid-fermentation, then declined during maturation. While microbial compositions were globally comparable between the two jars during mid-fermentation and maturation stages, differences between the two jars were mainly detected during early fermentation stage (D0 until D10). No significant sensorial differences were observed between the final products made in the two jars. Neither coliforms nor were detected in their viable state, starting D7 in both jars, suggesting the antimicrobial properties of the product.
PubMed: 37628130
DOI: 10.3390/foods12163131 -
Foods (Basel, Switzerland) Nov 2022Pit mud, a specific fermented soil, is an essential material for the fermentation of Chinese strong-flavour liquor. However, few studies to date have sought to...
Pit mud, a specific fermented soil, is an essential material for the fermentation of Chinese strong-flavour liquor. However, few studies to date have sought to characterize the spatial profiles of pit mud fungal communities in fermentation cellars from Chinese strong-flavour liquor distilleries. In this analysis, differences in fungal community structures and physicochemical properties in pit mud samples from different spatial positions within fermentation cellars were analyzed, revealing unique characteristic multidimensional pit mud fungal community profiles. , , , , , , , , were dominant in the pit mud samples form the upper cellar wall, whereas , , , , , , , , , were predominant in the middle cellar wall. , , , , , and are majorly present in the down cellar wall layer. , , , , , and were identified as the dominant fungi in pit mud samples from the cellar bottom. Additionally, and are present at notably high levels in all layers of pit mud samples. Moisture, pH, PO, acetic acid, humus, K, Mg, Ca, butyric acid, and caproic acid levels in these different pit mud positions exhibited a rising incremental pattern from the upper wall layer to the bottom layer, whereas lactic acid levels were significantly lower in the bottom pit mud layer relative to these other layers. Moisture, pH, and NH-N were identified as the three most significant factors associated with fungal community composition through a redundancy analysis. Overall, these findings may offer a theoretical foundation for future efforts to improve or standardize artificial pit mud.
PubMed: 36429136
DOI: 10.3390/foods11223544 -
Microorganisms Nov 2021Human living environments and health are seriously affected by the odor produced from fermentation of livestock and poultry manure. In order to reduce the odor pollution...
Human living environments and health are seriously affected by the odor produced from fermentation of livestock and poultry manure. In order to reduce the odor pollution caused by livestock and poultry manure, efficient strains were screened and two methods were tried in this study. The orthogonal test design was used to analyze the gas produced by pig manure under different conditions of temperature, time, wheat straw doping amount and calcium carbonate doping amount. Then, according to ammonia, hydrogen sulfide and comprehensive odor removal effects, the high efficiency of deodorizing strains were screened. The results showed that pig manure produced the least odor when the temperature was 20 °C, added 0% calcium carbonate, 20% wheat straw and waited for 48 h. Three strains were screened to inhibit the odor production of pig manure: , and , showed that their highest removal rate of ammonia and hydrogen sulfide gas could reach 96.58% and 99.74% among them; while for three strains of end-control pig manure stench: , and , the highest removal rate of ammonia and hydrogen sulfide gas reached 85.91% and 90.80% among them. This research provides bacteria resources as the high-efficiency deodorizing function for the source suppression and the end treatment of the odor gas of pig manure, which has high application value for the control of odor pollution.
PubMed: 34946090
DOI: 10.3390/microorganisms9122488 -
Microorganisms Jun 2020To investigate the effects of crude -glucosidases from SLY-4 (SLY-4E), F2-24 (F2-24E), and HX-13 (HX-13E) on flavor complexity and characteristics of wines, grape...
To investigate the effects of crude -glucosidases from SLY-4 (SLY-4E), F2-24 (F2-24E), and HX-13 (HX-13E) on flavor complexity and characteristics of wines, grape juice was fermented by with the addition of SLY-4E, F2-24E and HX-13E, respectively. The growth and sugar consumption kinetics of , the physicochemical characteristics, the volatile compounds, and the sensory dimensions of wines were analyzed. Results showed that adding SLY-4E, F2-24E, and HX-13E into must had no negative effect on the fermentation and physicochemical characteristics of wines, but increased the content of terpenes, esters, and fatty acids, while decreased the C compound content. Each wine had its typical volatile compound profiles. Adding SLY-4E or F2-24E into must could significantly improve the flavor complexity and characteristics of wines. These results would provide not only an approach to improve flavor complexity and characteristics of wines, but also references for application of -glucosidases from other sources.
PubMed: 32599830
DOI: 10.3390/microorganisms8060953 -
Foods (Basel, Switzerland) May 2022Ulcerative colitis (UC) is a chronic inflammatory bowel disease. The purpose of this study was to investigate the ameliorating effects of three yeast strains, I4, 30...
Ulcerative colitis (UC) is a chronic inflammatory bowel disease. The purpose of this study was to investigate the ameliorating effects of three yeast strains, I4, 30 and 11, isolated from traditional fermented dairy food in Xinjiang, China, on the ulcerative colitis symptoms of Balb/c mice treated by dextran sulfate sodium (DSS). Among which, I4 had good tolerance to simulated gastrointestinal juice and strong adhesion to HT-29 cells monolayers. Furthermore, the three yeast strains were oral administered to Balb/c mice with DSS induced colitis. The weight loss, colon shortening and histological injury of colitis mice were ameliorated. Then, oral administration of I4 improved the immune state by reducing the contents of TNF-α, IL-6 and IL-1β and increasing immunoglobulin. The relative expression of intestinal barrier proteins Claudin-1, Occludin and Zonula Occludins-1 (ZO-1) of the mice enhanced, and the short chain fatty acids (SCFAs) content such as Propionic acid, Butyric acid, Isobutyric acid and Isovaleric acid in the feces of the mice increased to varying degrees, after I4 treatment compared with the model group of drinking 3% DSS water without yeast treatment. Moreover, I4 treatment lifted the proportion of beneficial bacteria such as Muribaculaceae, Lactobacillaceae and Rikenellaceae in the intestinal tract of the mice, the abundance of harmful bacteria such as and was decreased. These results suggested that I4 could alleviate DSS induced colitis in mice by enhancing intestinal barrier function and regulating intestinal flora balance.
PubMed: 35627006
DOI: 10.3390/foods11101436