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1.
BMC Microbiol ; 24(1): 163, 2024 May 14.
Article En | MEDLINE | ID: mdl-38745280

Spontaneous fermentation of cereals like millet involves a diverse population of microbes from various sources, including raw materials, processing equipment, fermenting receptacles, and the environment. Here, we present data on the predominant microbial species and their succession at each stage of the Hausa koko production process from five regions of Ghana. The isolates were enumerated using selective media, purified, and phenotypically characterised. The LAB isolates were further characterised by 16S rRNA Sanger sequencing, typed using (GTG)5 repetitive-PCR, and whole genome sequencing, while 28S rRNA Sanger sequencing was performed for yeast identification. The pH of the millet grains ranged from mean values of 6.02-6.53 to 3.51-3.99 in the final product, depending on the processors. The mean LAB and yeast counts increased during fermentation then fell to final counts of log 2.77-3.95 CFU/g for LAB and log 2.10-2.98 CFU/g for yeast in Hausa koko samples. At the various processing stages, the counts of LAB and yeast revealed significant variations (p < 0.0001). The species of LAB identified in this study were Limosilactobacillus pontis, Pediococcus acidilactici, Limosilactobacillus fermentum, Limosilactobacillus reuteri, Pediococcus pentosaceus, Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, Schleiferilactobacillus harbinensis, and Weissella confusa. The yeasts were Saccharomyces cf. cerevisiae/paradoxus, Saccharomyces cerevisiae, Pichia kudriavzevii, Clavispora lusitaniae and Candida tropicalis. The identification and sequencing of these novel isolates and how they change during the fermentation process will pave the way for future controlled fermentation, safer starter cultures, and identifying optimal stages for starter culture addition or nutritional interventions. These LAB and yeast species are linked to many indigenous African fermented foods, potentially acting as probiotics in some cases. This result serves as the basis for further studies into the technological and probiotic potential of these Hausa koko microorganisms.


Fermentation , Fermented Foods , Food Microbiology , Millets , Yeasts , Ghana , Yeasts/classification , Yeasts/isolation & purification , Yeasts/genetics , Yeasts/metabolism , Fermented Foods/microbiology , Millets/microbiology , Lactobacillales/classification , Lactobacillales/isolation & purification , Lactobacillales/genetics , Lactobacillales/metabolism , RNA, Ribosomal, 16S/genetics , Phylogeny , Hydrogen-Ion Concentration , Edible Grain/microbiology
2.
Environ Microbiol Rep ; 16(3): e13213, 2024 Jun.
Article En | MEDLINE | ID: mdl-38738810

Since a significant proportion of plant matter is consumed by herbivores, a necessary adaptation for many phyllosphere microbes could be to survive through the guts of herbivores. While many studies explore the gut microbiome of herbivores by surveying the microbiome in their frass, few studies compare the phyllosphere microbiome to the gut microbiome of herbivores. High-throughput metabarcode sequencing was used to track the fungal community from milkweed (Asclepias spp.) leaves to monarch caterpillar frass. The most commonly identified fungal taxa that dominated the caterpillar frass after the consumption of leaves were yeasts, mostly belonging to the Basidiomycota phylum. While most fungal communities underwent significant bottlenecks and some yeast taxa increased in relative abundance, a consistent directional change in community structure was not identified from leaf to caterpillar frass. These results suggest that some phyllosphere fungi, especially diverse yeasts, can survive herbivory, but whether herbivory is a key stage of their life cycle remains uncertain. For exploring phyllosphere fungi and the potential coprophilous lifestyles of endophytic and epiphytic fungi, methods that target yeast and Basidiomycota fungi are recommended.


Asclepias , Fungi , Herbivory , Plant Leaves , Animals , Plant Leaves/microbiology , Asclepias/microbiology , Fungi/classification , Fungi/genetics , Fungi/isolation & purification , Fungi/physiology , Yeasts/classification , Yeasts/isolation & purification , Yeasts/genetics , Mycobiome , Basidiomycota/classification , Basidiomycota/genetics , Basidiomycota/physiology , Basidiomycota/isolation & purification , Gastrointestinal Microbiome , Larva/microbiology , Moths/microbiology
3.
J Appl Microbiol ; 135(5)2024 May 01.
Article En | MEDLINE | ID: mdl-38621715

AIMS: To compare the species diversity and composition of indigenous yeast communities of hybrid grapes from conventionally and organically cultivated vineyards of an emerging cool-climate wine producing region. METHODS AND RESULTS: Illumina MiSeq sequences from L'Acadie blanc grape musts were processed and filtered to characterize indigenous yeast communities in organic and conventional vineyards of the Annapolis Valley wine region in Nova Scotia, Canada. While cultivation practice was not associated with yeast diversity or species richness, there was a strong effect on yeast community composition, with conventional vineyards characterized by higher proportions of Sporidiobolales and Filobasidium magnum, and organic vineyards supporting Filobasidium species other than F. magnum and higher proportions of Symmetrospora. There was also variation in yeast community composition among individual vineyards, and from year to year. CONCLUSIONS: This is the first comprehensive assessment of yeasts associated with hybrid grapes grown using different cultivation practices in a North American cool climate wine region. Communities were dominated by basidiomycete yeasts and species composition of these yeasts differed significantly between vineyards employing organic and conventional cultivation practices. The role of basidiomycete yeasts in winemaking is not well understood, but some species may influence wine characteristics.


Vitis , Wine , Yeasts , Vitis/microbiology , Wine/microbiology , Wine/analysis , Yeasts/genetics , Yeasts/classification , Yeasts/isolation & purification , Nova Scotia , Farms , Organic Agriculture
4.
Med Mycol ; 62(5)2024 May 03.
Article En | MEDLINE | ID: mdl-38627248

Although Candida species are the most common cause of fungemia, non-Candida rare yeasts (NCY) have been increasingly reported worldwide. Although the importance of these yeast infections is recognized, current epidemiological information about these pathogens is limited, and they have variable antifungal susceptibility profiles. In this study, we aimed to evaluate the clinical characteristics for fungemia caused by NCY by comparing with candidemia. The episodes of NCY fungemia between January 2011 and August 2023 were retrospectively evaluated in terms of clinical characteristics, predisposing factor, and outcome. In addition, a candidemia group, including patients in the same period was conducted for comparison. Antifungal susceptibility tests were performed according to the reference method. A total of 85 patients with fungemia episodes were included: 25 with NCY fungemia and 60 with candidemia. Fluconazole had high minimal inhibitory concentration (MIC) values against almost all NCY isolates. The MIC values for voriconazole, posaconazole, and amphotericin B were ≤ 2 µg/ml, and for caspofungin and anidulafungin were ≥ 1 µg/ml against most of isolates. Hematological malignancies, immunosuppressive therapy, neutropenia and prolonged neutropenia, polymicrobial bacteremia/fungemia, preexposure to antifungal drugs, and breakthrough fungemia were associated with NCY fungemia, whereas intensive care unit admission, diabetes mellitus, urinary catheters, and total parenteral nutrition were associated with candidemia. In conclusion, the majority of fungemia due to NCY species was the problem, particularly in hematology units and patients with hematological malignancy. Preexposure to antifungal drugs likely causes a change in the epidemiology of fungemia in favor of non-albicans Candida and/or NCY.


Among all fungemia episodes, hematological malignancies, immunosuppressive therapy, neutropenia, and preexposure to antifungals were risk factors for non-Candida yeast fungemia; diabetes mellitus, urinary catheters, and total parenteral nutrition were risks for candidemia.


Antifungal Agents , Candida , Candidemia , Fungemia , Microbial Sensitivity Tests , Tertiary Care Centers , Humans , Retrospective Studies , Tertiary Care Centers/statistics & numerical data , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Male , Female , Middle Aged , Aged , Candida/drug effects , Candida/isolation & purification , Candida/classification , Fungemia/microbiology , Fungemia/epidemiology , Fungemia/drug therapy , Adult , Candidemia/microbiology , Candidemia/epidemiology , Candidemia/drug therapy , Yeasts/isolation & purification , Yeasts/drug effects , Yeasts/classification , Aged, 80 and over , Fluconazole/pharmacology , Fluconazole/therapeutic use , Young Adult
5.
Int J Food Microbiol ; 417: 110688, 2024 Jun 02.
Article En | MEDLINE | ID: mdl-38615425

Taggiasca table olives are typical of Liguria, a Northwestern Italian region, produced with a spontaneous fermentation carried out by placing the raw drupes directly into brine with a salt concentration of 8-12 % w/v. Such concentrations limit the development of unwanted microbes and favor the growth of yeasts. This process usually lasts up to 8 months. Yeasts are found throughout the entire fermentation process and they are mainly involved in the production of volatile organic compounds, which strongly impact the quality of the final product. The aim of this study was to evaluate the dynamics of autochthonous yeasts in brines and olives in a spontaneous process with no lye pre-treatment or addition of acids in the fermenting brine with 10 % NaCl (w/v) in two batches during 2021 harvest. Three hundred seventy-three yeast colonies were isolated, characterized by rep-PCR and identified by the D1/D2 region of the 26S rRNA gene sequencing. Mycobiota was also studied by 26S rRNA gene metataxonomics, while metabolome was assessed through GC-MS analysis. Traditional culture-dependent methods showed the dominance of Candida diddensiae, Wickerhamomyces anomalus, Pichia membranifaciens and Aureobasidium pullulans, with differences in species distribution between batches, sampling time and type of sample (olives/brines). Amplicon-based sequencing confirmed the dominance of W. anomalus in batch 1 throughout the entire fermentation, while Cyteromyces nyonsensis and Aureobasidium spp. were most abundant in the fermentation in batch 2. Volatilome results were analyzed and correlated to the mycobiota data, confirming differences between fermentation stages. Given the high appreciation for this traditional food, this study helps elucidate the mycobiota associated to Taggiasca cv. table olives and its relationship with the quality of the final product.


Fermentation , Food Microbiology , Olea , Volatile Organic Compounds , Yeasts , Olea/microbiology , Volatile Organic Compounds/analysis , Volatile Organic Compounds/metabolism , Yeasts/metabolism , Yeasts/classification , Yeasts/isolation & purification , Yeasts/genetics , Italy , Salts
6.
Diagn Microbiol Infect Dis ; 109(2): 116270, 2024 Jun.
Article En | MEDLINE | ID: mdl-38518388

MALDI-TOF MS identifications of microorganisms in a clinical laboratory were investigated, comparing steel targets with MBT Biotargets. By using MBT Biotargets, the score values of yeast identifications increased, whereas the score values of Gram-negative bacteria decreased. Switching to MBT Biotargets did not negatively impact overall frequencies of high confidence identifications.


Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Steel , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Humans , Steel/chemistry , Bacteria/classification , Bacteria/isolation & purification , Bacteria/genetics , Microbiological Techniques/methods , Yeasts/isolation & purification , Yeasts/classification , Yeasts/genetics
7.
Biol Trace Elem Res ; 201(6): 3069-3076, 2023 Jun.
Article En | MEDLINE | ID: mdl-35915280

The Çökelek samples what 30 different were collected from randomly local bazaars to investigate heavy metal contaminant and mineral levels and some physicochemical and microbiological properties of samples. While the Pb was identified in 6 of the 30 samples, the As was only found in 4 of the samples. The mean major and trace element contents of Çökelek samples were ordered as Na > P > Ca > K > Mg and Al > Zn > Ni > Cu, respectively. The physicochemical properties indicated a high deviation among samples. The mean total solids, ash, salt, fat, protein waters soluble nitrogen contents, and sample ripening index were 29.83%, 1.88%, 0.68%, 4.31%, 19.84%, 0.33%, and 1.79%, respectively. The mean total aerobic mesophilic bacteria (TAMB) count of Çökelek samples was found as 8.26 log CFU g-1. The coliform bacteria and yeast-mold counts were detected in 11 and 27 of 30 samples, respectively. The mean coliform and yeast-mold counts were 1.82 log CFU g-1 and 7.11 log CFU g-1, respectively. Traditional cheeses are not mentioned in legal laws such as the Turkish Food Codex. So, there is no legal limit and standard production processes. This situation is a problem in terms of traditional cheese quality. For this reason, traditional cheese should perform further studied, and determine the legal limits.


Cheese , Food Microbiology , Cheese/analysis , Cheese/microbiology , Food Handling , Fungi/isolation & purification , Sodium Chloride , Turkey , Yeasts/isolation & purification , Colony Count, Microbial , Enterobacteriaceae/isolation & purification
8.
Molecules ; 27(3)2022 Jan 28.
Article En | MEDLINE | ID: mdl-35164165

Yeasts are one of the main ingredients responsible for flavor precursors production associated with sensorial characteristics in chocolate. Using wild yeast isolated from cocoa beans fermentation is emerging as a strategy for developing starter cultures. However, the volatile compounds (VCs) produced by yeasts are not yet known. This study aimed to select wild yeasts with the potential to produce volatile compounds associated with desirable flavor attributes. A total of 150 wild yeasts strains were isolated from the spontaneous cocoa beans fermentation, of which 40 were identified by morphology and physiological features. VCs produced were identified and quantified using SPME-GC-MS and GC-FID and profiles were evaluated statistically by PCA and cluster analysis for the compounds that had a high odor threshold value. Thirty-six VCs produced by these yeasts were identified into six main families, namely esters, alcohols, acids, aldehydes, ketones, and pyrazines. PCA showed the separation of the yeasts into two main clusters. Strains, Y195 and Y246, belong to the first cluster and are the highest producers of alcohols related to floral perceptions. In the second cluster, thirty-three yeasts were grouped by their ability to produce esters. Of all of them, Y110MRS stood out for producing 2-phenyl ethyl acetate and isoamyl acetate associated with fruity perceptions. This screening allowed us to identify yeasts that produced VCs of technological interest and which could be used to develop a starter culture.


Cacao/microbiology , Fermentation , Volatile Organic Compounds/analysis , Yeasts/isolation & purification , Alcohols/analysis , Aldehydes/analysis , Cacao/metabolism , Chocolate/analysis , Pyrazines/analysis , Yeasts/metabolism
10.
J Clin Microbiol ; 60(1): e0139821, 2022 01 19.
Article En | MEDLINE | ID: mdl-34669460

Fourier transform infrared (FTIR) spectroscopy has demonstrated applicability as a reagent-free whole-organism fingerprinting technique for both microbial identification and strain typing. For routine application of this technique in microbiology laboratories, acquisition of FTIR spectra in the attenuated total reflectance (ATR) mode simplifies the FTIR spectroscopy workflow, providing results within minutes after initial culture without prior sample preparation. In our previous central work, 99.7% correct species identification of clinically relevant yeasts was achieved by employing an ATR-FTIR-based method and spectral database developed by our group. In this study, ATR-FTIR spectrometers were placed in 6 clinical microbiology laboratories over a 16-month period and were used to collect spectra of routine yeast isolates for on-site identification to the species level. The identification results were compared to those obtained from conventional biochemical tests and/or matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Isolates producing discordant results were reanalyzed by routine identification methods, ATR-FTIR spectroscopy, and PCR gene sequencing of the D1/D2 and internal transcribed spacer (ITS) regions. Among the 573 routine clinical yeast isolates collected and identified by the ATR-FTIR-based method, 564 isolates (98.4%) were correctly identified at the species level, while the remaining isolates were inconclusive with no misidentifications. Due to the low prevalence of Candida auris in routine isolates, additional randomly selected C. auris (n = 24) isolates were obtained for evaluation and resulted in 100% correct identification. Overall, the data obtained in our multicenter evaluation study using multiple spectrometers and system operators indicate that ATR-FTIR spectroscopy is a reliable, cost-effective yeast identification technique that provides accurate and timely (∼3 min/sample) species identification promptly after the initial culture.


Yeasts , Fourier Analysis , Humans , Spectroscopy, Fourier Transform Infrared/methods , Yeasts/isolation & purification
11.
Microbiol Spectr ; 9(3): e0140421, 2021 12 22.
Article En | MEDLINE | ID: mdl-34935420

In the beer brewing industry, microbial spoilage presents a consistent threat that must be monitored and controlled to ensure the palatability of a finished product. Many of the predominant beer spoilage microbes have been identified and characterized, but the mechanisms of contamination and persistence remain an open area of study. Postproduction, many beers are distributed as kegs that are attached to draft delivery systems in retail settings where ample opportunities for microbial spoilage are present. As such, restaurants and bars can experience substantial costs and downtime for cleaning when beer draft lines become heavily contaminated. Spoilage monitoring on the retail side of the beer industry is often overlooked, yet this arena may represent one of the largest threats to the profitability of a beer if its flavor profile becomes substantially distorted by contaminating microbes. In this study, we sampled and cultured microbial communities found in beers dispensed from a retail draft system to identify the contaminating bacteria and yeasts. We also evaluated their capability to establish new biofilms in a controlled setting. Among four tested beer types, we identified over a hundred different contaminant bacteria and nearly 20 wild yeasts. The culturing experiments demonstrated that most of these microbes were viable and capable of joining new biofilm communities. These data provide an important reference for monitoring specific beer spoilage microbes in draft systems and we provide suggestions for cleaning protocol improvements. IMPORTANCE Beer production, packaging, and service are each vulnerable to contamination by microbes that metabolize beer chemicals and impart undesirable flavors, which can result in the disposal of entire batches. Therefore, great effort is taken by brewmasters to reduce and monitor contamination during production and packaging. A commonly overlooked quality control stage of a beer supply chain is at the retail service end, where beer kegs supply draft lines in bars and restaurants under nonsterile conditions. We found that retail draft line contamination is rampant and that routine line cleaning methods are insufficient to efficiently suppress beer spoilage. Thus, many customers unknowingly consume spoiled versions of the beers they consume. This study identified the bacteria and yeast that were resident in retail draft beer samples and also investigated their abilities to colonize tubing material as members of biofilm communities.


Bacterial Physiological Phenomena , Beer/microbiology , Biofilms , Microbiota , Yeasts/physiology , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , Food Contamination/analysis , Food Microbiology , Yeasts/classification , Yeasts/genetics , Yeasts/isolation & purification
12.
FEMS Microbiol Lett ; 368(20)2021 11 30.
Article En | MEDLINE | ID: mdl-34788824

Nine morphologically distinct halophilic yeasts were isolated from Makgadikgadi and Sua pans, as pristine and extreme environments in Botswana. Screening for biosurfactant production showed that Rhodotorula mucilaginosa SP6 and Debaryomyces hansenii MK9 exhibited the highest biosurfactant activity using Xanthocercis zambesiaca seed powder as a novel and alternative inexpensive carbon substrate. Chemical characterization of the purified biosurfactants by Fourier Transform Infra-Red spectroscopy suggested that the biosurfactant from R. mucilaginosa SP6 was a rhamnolipid-type whereas the biosurfactant from D. hansenii MK9 was a sophorolipid-type. The two biosurfactants exhibited antimicrobial activities against eight pathogenic bacteria and fungal strains (Proteus vulgaris, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Micrococcus luteus, Cryptococcus neoformans, Candida albicans and Aspergilus niger). The sophorolopid-type biosurfactant was found to be the most potent among the antimicrobial drug resistant strains tested. The findings open up prospects for the development of environmentally friendly antimicrobial drugs that use an inexpensive source of carbon to reduce the costs associated with the production of biosurfactants.


Extreme Environments , Surface-Active Agents , Yeasts , Anti-Infective Agents/isolation & purification , Anti-Infective Agents/metabolism , Anti-Infective Agents/pharmacology , Bacteria/drug effects , Botswana , Carbon/metabolism , Debaryomyces/chemistry , Debaryomyces/metabolism , Fungi/drug effects , Industrial Microbiology , Rhodotorula/chemistry , Rhodotorula/metabolism , Surface-Active Agents/isolation & purification , Surface-Active Agents/metabolism , Surface-Active Agents/pharmacology , Yeasts/chemistry , Yeasts/isolation & purification , Yeasts/metabolism
13.
FEMS Microbiol Lett ; 368(20)2021 11 27.
Article En | MEDLINE | ID: mdl-34755861

Non-Saccharomyces yeasts are important players during winemaking and may come from grapes grown in vineyards. To study the diversity of non-Saccharomyces yeasts on grape berry surfaces, 433 strains were isolated from different Cabernet Sauvignon vineyards grown in Henan Province. Our results demonstrated that these strains were classified into 16 morphotypes according to their growth morphology on Wallerstein Laboratory agar medium, and were identified as seven species from four genera-Hanseniaspora opuntiae, Hanseniaspora vineae, Hanseniaspora uvarum, Pichia occidentalis, Pichia kluyveri, Issatchenkia terricola and Saturnispora diversa-based on a series of molecular biological experiments. Hanseniaspora opuntiae was obtained from all sampling sites except Changyuan County, while Pichia kluyveri and Saturnispora diversa were only found in sites of Zhengzhou Grape Resource Garden and Minquan County, respectively. The site Minquan was home of the greatest species richness, while only one single species (Hanseniaspora opuntiae) was detected at NAPA winery from Zhengzhou or at Anyang County. Finally, this study suggested that the geographic distribution and diversity of non-Saccharomyces yeast populations on Cabernet Sauvignon grape berries were likely to be determined by a combination of grape varieties and environmental factors.


Biodiversity , Fruit , Vitis , Yeasts , China , Farms , Fermentation , Fruit/microbiology , Hanseniaspora/classification , Hanseniaspora/isolation & purification , Pichia/classification , Pichia/isolation & purification , Saccharomycetales/classification , Saccharomycetales/isolation & purification , Vitis/microbiology , Wine/microbiology , Yeasts/classification , Yeasts/isolation & purification
14.
Biol Futur ; 72(3): 325-337, 2021 Sep.
Article En | MEDLINE | ID: mdl-34554551

Plasmodial resistance to a variety of plant-based antimalarial drugs has led toward the discovery of more effective antimalarial compounds having chemical or biological origin. Since natural compounds are considered as safer drugs, in this study, yeast strains were identified and compared for the production of carotenoids that are well-known antioxidants and this metabolite was tested for its antiparasitic activity. Plasmodium falciparum 3D7 strain was selected as the target parasite for evaluation of antimalarial activity of yeast carotenoids using in vitro studies. Data were analyzed by FACS (fluorescence-activated cell sorter) and counted via gold standard Giemsa-stained smears. The extracted yeast carotenoids showed a profound inhibitory effect at a concentration of 10-3 µg/µl and 10-4 µg/µl when compared to ß- carotene as control. SYBR Green1 fluorescent dye was used to confirm the decrease in parasitaemia at given range of concentration. Egress assay results suggested that treated parasite remained stalled at schizont stage with constricted morphology and were darkly stained. Non-toxicity of carotenoids on erythrocytes and on human liver hepatocellular carcinoma cells (HepG2 cells) was shown at a given concentration. This report provides strong evidence for antimalarial effects of extracted yeast carotenoids, which can be produced via a sustainable and cost-effective strategy and may be scaled up for industrial application.


Antimalarials/standards , Carotenoids/analysis , Carotenoids/isolation & purification , Plasmodium falciparum/drug effects , Yeasts/metabolism , Antimalarials/pharmacology , Antimalarials/therapeutic use , Malaria, Falciparum/drug therapy , Malaria, Falciparum/physiopathology , Yeasts/isolation & purification
15.
BMC Vet Res ; 17(1): 288, 2021 Aug 28.
Article En | MEDLINE | ID: mdl-34454490

BACKGROUND: Lifestyle factors such as hair length, the frequency of ear cleaning and bathing, age, cat rearing, and sex may contribute to opportunistic yeast infections in the external ear canal of cats. This study aimed to determine the prevalence of commensal yeast organisms in cats' external ear canals, evaluate their predisposing lifestyle factors, and test the susceptibility of Malassezia pachydermatis to antifungal agents. RESULTS: A total of 53 cats (33 male and 20 female) seronegative for feline leukemia virus and feline immunodeficiency virus were enrolled in this study. Their mean age (± standard deviation) was 6.04 (± 3.49) years. Fungal cultures and polymerase chain reaction tests were performed to identify the yeast species derived from the external ear canal. The association between lifestyle factors and the presence of M. pachydermatis was evaluated using Fisher's exact test. The susceptibility of M. pachydermatis to antifungal agents was also analyzed. M. pachydermatis was the most frequently recovered yeast species, with a prevalence of 50.94 % (95 % confidence interval [CI]: 36.84-64.94 %). There was an association between hair length and a positive culture for M. pachydermatis (p = 0.0001). The odds of a negative culture for M. pachydermatis among short-haired cats was 11.67 (95 % CI, 3.22-42.24) times higher than that among long-haired cats (p = 0.0002). There was also an association between the frequency of ear cleaning and the presence of M. pachydermatis (p = 0.007). The odds of a negative culture for M. pachydermatis in cats that were receiving ear cleaning at intervals of ≤ 2 weeks was 5.78 (95 % CI, 1.67-19.94) times greater than that of cats receiving ear cleaning at intervals greater than 2 weeks or never (p = 0.0055). Ranges of minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations for itraconazole, ketoconazole, miconazole, and terbinafine against M. pachydermatis were ≤ 0.063-4 and ≤ 0.063-≥32, ≤ 0.063-8 and 0.125-≥32, ≤ 0.063-≥32 and 0.5-≥32, and ≤ 0.016-1 and 0.125-8 µg/ml, respectively. CONCLUSIONS: M. pachydermatis was the most commonly identified yeast organism in the external ear canal of healthy cats. Hair length and the frequency of ear cleaning played a role in the colonization of M. pachydermatis. The M. pachydermatis isolates had various MIC levels for common fungicides.


Antifungal Agents/pharmacology , Cat Diseases/microbiology , Ear Canal/microbiology , Yeasts/isolation & purification , Animal Fur , Animals , Cats , Female , Malassezia/drug effects , Malassezia/isolation & purification , Male , Prevalence , Yeasts/drug effects
16.
Food Microbiol ; 100: 103864, 2021 Dec.
Article En | MEDLINE | ID: mdl-34416964

While the trend in winemaking is toward reducing the inputs and especially sulphites utilization, emerging technologies for the preservation of wine is a relevant topic for the industry. Amongst yeast spoilage in wine, Brettanomyces bruxellensis is undoubtedly the most feared. In this study, UV-C treatment is investigated. This non-thermal technique is widely used for food preservation. A first approach was conducted using a drop-platted system to compare the sensitivity of various strains to UV-C surface treatment. 147 strains distributed amongst fourteen yeast species related to wine environment were assessed for six UV-C doses. An important variability in UV-C response was observed at the interspecific level. Interestingly, cellar resident species, which are mainly associated with wine spoilage, shows higher sensitivity to UV-C than vineyard-resident species. A focus on B. bruxellensis species with 104 screened strains highlighted an important effect of the UV-C, with intra-specific variation. This intra-specific variation was confirmed on 6 strains in liquid red wine by using a home-made pilot. 6624 J.L-1 was enough for a reduction of 5 log10 of magnitude for 5 upon 6 strains. These results highlight the potential of UV-C utilization against wine yeast spoiler at cellar scale.


Wine/microbiology , Yeasts/radiation effects , Phylogeny , Species Specificity , Ultraviolet Rays , Wine/analysis , Yeasts/genetics , Yeasts/growth & development , Yeasts/isolation & purification
17.
Can J Microbiol ; 67(7): 497-505, 2021 Jul.
Article En | MEDLINE | ID: mdl-34232751

To colonize and infect the host, arthroconidial yeasts must avoid being killed by the host's defenses. The formation of biofilms on implanted devices allows fungi to avoid host responses and to disseminate into the host. To better study the mechanisms of infection by arthroconidial yeasts, adherence and biofilm formation were assayed using patient samples collected over 10 years. In clinical samples, adherence varies within species, but the relative adherence is constant for those samples isolated from the same infection site. Herein we document, for the first time, in-vitro biofilm formation by Trichosporon dohaense, T. ovoides, T. japonicum, T. coremiiforme, Cutaneotrichosporon mucoides, Cutaneotrichosporon cutaneum, Galactomyces candidus, and Magnusiomyces capitatus on clinically relevant catheter material. Analysis of biofilm biomass assays indicated that biofilm mass changes less than 2-fold, regardless of the species. Our results support the hypothesis that most pathogenic fungi can form biofilms, and that biofilm formation is a source of systemic infections.


Biofilms , Candida/physiology , Mycoses/microbiology , Yeasts/physiology , Candida/classification , Candida/genetics , Candida/isolation & purification , Humans , Yeasts/classification , Yeasts/genetics , Yeasts/isolation & purification
18.
BMC Microbiol ; 21(1): 170, 2021 06 06.
Article En | MEDLINE | ID: mdl-34090353

BACKGROUND: The unique climatic conditions of the Xinjiang region nurture rich melon and fruit resources, the melon and fruit sugar sources provide sufficient nutrients for the survival of yeast, and the diverse habitats accompanied by extreme climatic conditions promote the production of yeast diversity and strain resources. However, the relationship between yeast species and their relationship with environmental factors in the soil of Xinjiang specialty cash crop Hami melon is not clear. Here, we aimed to characterize the diversity, community structure, and relationship between yeast species and environmental factors in Hami melon orchards soils in different regions of Xinjiang, China. RESULTS: Based on Illumina MiSeq high-throughput sequencing analysis of the D1 domain of the LSU rRNA genes, the community richness of yeast in the soil of Northern Xinjiang was higher than in the Southern and Eastern Xinjiang, but the community diversity was significantly lower in the Northern Xinjiang than in the Southern and Eastern Xinjiang. A total of 86 OTUs were classified into 59 genera and 86 species. Most OTUs (90.4%) belonged to the Basidiomycota; only a few (9.6%) belonged to Ascomycota. The most dominant species in the Southern, Eastern and Northern Xinjiang were Filobasidium magnum (17.90%), Solicoccozyma aeria (35.83%) and Filobasidium magnum (75.36%), respectively. Principal coordinates analysis (PCoA) showed that the yeast community composition in the soils of the three regions were obviously different, with the Southern and Eastern Xinjiang having more similar yeast community. Redundancy analysis (RDA) showed that soil factors such as conductivity (CO), total phosphorus (TP) and Total potassium (TK) and climate factors such as average annual precipitation (PRCP), relative humidity (RH) and net solar radiation intensity (SWGNT) were significantly correlated with yeast communities (P < 0.05). CONCLUSION: There are abundant yeast resources in the rhizosphere soil of Hami melon orchard in Xinjiang, and there are obvious differences in the diversity and community structure of yeast in the three regions of Xinjiang. Differences in climatic factors related to precipitation, humidity and solar radiation intensity and soil factors related to conductivity, total phosphorus and total potassium are key factors driving yeast diversity and community structure.


Cucurbitaceae/growth & development , Soil Microbiology , Yeasts/isolation & purification , China , Cucurbitaceae/metabolism , High-Throughput Nucleotide Sequencing , Microbiota , Phosphorus/analysis , Phosphorus/metabolism , Rhizosphere , Soil/chemistry , Yeasts/classification , Yeasts/genetics
19.
Molecules ; 26(11)2021 May 21.
Article En | MEDLINE | ID: mdl-34063892

Sea buckthorn (Hippophae rhamnoides L.) is recognized as a valuable source of vitamin C and antioxidants, frequently used as nutraceuticals and cosmeceuticals. In the present study, attempts are made to produce and characterize a novel type of marmalade using sea buckthorn berries processed at 102 °C into marmalade in two combinations, with whole cane or stevia sugar. Changes in the phytochemical profile, antioxidant activity, color, shelf-life, texture, microbiological, and sensorial characteristics were determined. The total carotenoids content in the marmalades were significantly different, with values of 0.91 ± 0.03 mg/g dry weight (DW) in the sample with whole sugar cane (Cz) and 2.69 ± 0.14 mg/g DW in the sample with Stevia sugar (Cs). Significant values of polyphenols were found, of 59.41 ± 1.13 mg GAE/g DW in Cz and 72.44 ± 2.31 mg GAE/g DW in Cs, leading to an antioxidant activity of 45.12 ± 0.001 µMol Trolox/g DW and 118.07 ± 0.01 µMol Trolox/g DW, respectively. Accelerated storage study showed a decrease in all the phytochemicals, however no significant changes were found in antioxidant activity. Values of <100 CFU/g for yeasts and molds and <5 CFU/g for Enterobacteriaceae after 21 days of storage at the room temperature of the marmalades were determined. The sensorial and color results were more than acceptable. Overall, the results highlighted the potential of using sea buckthorn as a potential rich source of bioactive compounds to be used in the sugar-based products manufacturing.


Food Handling , Hippophae/chemistry , Stevia , Sugars , Antioxidants/analysis , Carotenoids/analysis , Colony Count, Microbial , Enterobacteriaceae/isolation & purification , Food Analysis , Food Microbiology , Fungi/isolation & purification , Phytochemicals/analysis , Yeasts/isolation & purification
20.
World J Microbiol Biotechnol ; 37(7): 118, 2021 Jun 16.
Article En | MEDLINE | ID: mdl-34131809

This review provides an overview of the application of next-generation sequencing (NGS) technologies for microbiome analysis of cocoa beans fermentation. The cocoa-producing regions where NGS has been applied include Brazil, Ghana, Ivory Coast, Cameroon, Nicaragua, and Colombia. The data collected were processed by principal component analysis (PCA) and Venn diagrams to perform a multivariate association between microbial diversity and cocoa-producing regions. NGS studies have confirmed the dominance of three major microbial groups revealed by culture-dependent approaches, i.e., lactic acid bacteria, acetic acid bacteria, and yeasts. However, a more complex microbial diversity has been revealed, comprising sub-dominant populations, late-growing species, and uncultivable microorganisms. A total of 99 microbial genera and species were for the first time reported in cocoa beans fermentation, such as Brevibacillus sp., Halomonas meridiana, Methylobacterium sp., Novosphingobium sp., and Paenibacillus pabuli. PCA and Venn diagrams showed that species composition is rarely fixed and often experiences fluctuations of varying degrees and at varying frequencies between different cocoa-producing regions. Understanding these differences will provide further directions for exploring the functional and metabolic activity of rare and abundant taxa, as well as their use as starter cultures to obtain high-quality cocoa beans.


Bacteria/classification , Cacao/microbiology , Sequence Analysis, DNA/methods , Yeasts/classification , Bacteria/genetics , Bacteria/isolation & purification , Bacterial Physiological Phenomena , DNA, Bacterial/genetics , DNA, Fungal/genetics , Fermentation , High-Throughput Nucleotide Sequencing , Phylogeny , Yeasts/genetics , Yeasts/isolation & purification , Yeasts/physiology
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