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Cureus Nov 2022In view of the growing incidence of pathogenic yeast infection all over the world, this study was undertaken to understand its etiology and epidemiology in Assam.
CONTEXT
In view of the growing incidence of pathogenic yeast infection all over the world, this study was undertaken to understand its etiology and epidemiology in Assam.
AIMS
To characterize and study the antifungal susceptibility pattern of the pathogenic yeasts from the clinical samples.
SETTINGS AND DESIGN
The study was a hospital-based cross-sectional study.
METHODS AND MATERIAL
150 patients were enrolled in the study and from which clinical samples were collected. A total of 83 samples showing the growth of yeast in culture were included in the study. The yeasts were identified by conventional and BioMerieux ID 32C and VITEK 2. Antifungal susceptibility test was done by disk diffusion method as per Clinical and Laboratory Standards Institute (CLSI), M44-A2.
STATISTICAL ANALYSIS USED
Data was analyzed using statistical software Epi-Info 7.1.2.0 (2013; CDC, Atlanta, USA). For comparison of categorical data, the Chi-square test or Fisher exact test was used. A value of less than 0.05 was considered statistically significant.
RESULTS
The most affected population was the age group of ≤10 years (32.5%) with male preponderance (67.5%). Yeasts were mostly isolated bloodstream infections (49.3%). The major risk factor was prolonged antibiotic intake. Predominant yeast isolates were (43.4%) followed by (19.3%). Emerging yeasts like (4.8%), (2.4%), and (1.2%) were also isolated. Amphotericin B was effective against all yeast isolates. All the isolates of were resistant to all the azoles.
CONCLUSIONS
The study reflects that there is a growing incidence of emerging yeast infections and efforts are to be made for their identification and antifungal susceptibility testing for the initiation of appropriate therapy.
PubMed: 36532931
DOI: 10.7759/cureus.31512 -
FEMS Immunology and Medical Microbiology Sep 1998Despite the development of drugs in the prophylaxis of pneumocystosis, Pneumocystis carinii remains a major opportunistic microorganism in immunosuppressed individuals,... (Review)
Review
Despite the development of drugs in the prophylaxis of pneumocystosis, Pneumocystis carinii remains a major opportunistic microorganism in immunosuppressed individuals, especially in human immunodeficiency virus-infected patients. Since side effects were frequently observed after administration of trimethoprim-sulfamethoxazole or pentamidine, the drugs which are mainly used in treating human P. carinii pneumonia (PCP), new therapeutic strategies should be developed. Over the last years, the inhibitory effect of a Pichia anomala killer toxin (PaKT), a molecule with a wide spectrum of antimicrobial activity, was characterized on P. carinii. The susceptibility of mouse and rat-derived Pneumocystis to PaKT has been demonstrated by in vitro attachment tests and in vivo infectivity assays. Nevertheless, PaKT is strongly antigenic, toxic and could not be used directly as a therapeutic agent. Then, a new strategy using killer toxin-like anti-idiotypic antibodies (KT-antiIds) mimicking the fungal toxin activity has been developed. Different KT-antiIds were obtained by idiotypic immunization with a monoclonal antibody (mabKT4). This mabKT4 neutralized the killer properties of the PaKT. KT-antiIds were produced by immunization against the variable domain (idiotype) of mAbKT4 (internal image of the killer toxin receptor), or they were obtained directly from vaginal fluid of patients affected by recurrent vaginal candidiosis. In this last case, such natural KT-antiIds were immunopurified by affinity-chromatography with mAbKT4 and their anti-P. carinii activity was then evaluated. Our results showed that both the in vitro attachment of rat-derived parasites and their infectivity to nude rats were inhibited by the KT-antiIds. With regard to KT-antiIds obtained by immunization, the antimicrobial activity of a monoclonal KT-antiIds (mAbK10) has been evaluated by using a PCP experimental nude rat model treated by mAbK10 administered by aerosol. The pneumocystosis extension was significantly reduced in this model. The monoclonal KT-antiIds were effective against P. carinii in reducing parasite proliferation in lungs of nude rats. Further experiments are in progress to study the in vivo anti-P. carinii activity of KT-antiIds by using recombinant single-chain of the variable fragment of KT-antiIds. Yeast killer toxin-like recombinant molecules could provide the basis for a new therapeutic strategy towards the control of pneumocystosis.
Topics: Animals; Antibodies, Anti-Idiotypic; Antibodies, Fungal; Humans; Killer Factors, Yeast; Mycotoxins; Pichia; Pneumocystis; Pneumonia, Pneumocystis; Recombinant Proteins
PubMed: 9792073
DOI: 10.1111/j.1574-695X.1998.tb01199.x -
Microorganisms Sep 2019This experiment was carried out to identify and select pectinolytic yeasts that have potential use as a starter culture for coffee fermentation during wet processing....
This experiment was carried out to identify and select pectinolytic yeasts that have potential use as a starter culture for coffee fermentation during wet processing. The coffee fruit was fermented for 48 h at 28 °C and a sample was taken from the fermented solution and spread onto yeast extract-peptone-dextrose agar (YPDA) media and incubated at 28 °C. A total of 28 yeasts were isolated, eight of which had the ability to produce pectinase enzymes. The species of those eight yeasts were molecularly identified and confirmed. These yeasts are (strain KNU18Y3), (strain KNU18Y4), (strain KNU18Y5 and KNU18Y6) (strain KNU18Y7 and KNU18Y8), and (strain KNU18Y12 and KNU18Y13). The pectin degradation index of (strain KNU18Y4), (strain KNU18Y3), and (strain KNU18Y6) were higher compared to the others, at 178%, 160%, and 152%, respectively. The pectinase enzyme assays were made on two growth media: coffee pulp media (CPM) and synthetic pectin media (SPM). (strain KNU18Y4) and (strain KNU18Y3) had great potential in producing polygalacturonase (PG) and pectin lyase (PL) compared to others in both media. However, strains (KNU18Y12 and KNU18Y13) produced higher pectin methylesterase (PME). Using MEGA 6 software, the phylogenetic trees were constructed to determine the evolutionary relationship of newly identified yeasts from our experiment and previously published yeast species. The sequences of the yeasts were deposited in the National Center for Biotechnology Information (NCBI) database.
PubMed: 31569406
DOI: 10.3390/microorganisms7100401 -
Microbial Cell Factories Sep 2015The product yield and titers of biological processes involving the conversion of biomass to desirable chemicals can be limited by environmental stresses encountered by...
BACKGROUND
The product yield and titers of biological processes involving the conversion of biomass to desirable chemicals can be limited by environmental stresses encountered by the microbial hosts used for the bioconversion. One of these main stresses is growth inhibition due to exposure to low pH conditions. In order to circumvent this problem, understanding the biological mechanisms involved in acid stress response and tolerance is essential. Characterisation of wild yeasts that have a natural ability to resist such harsh conditions will pave the way to understand the biological basis underlying acid stress resistance. Pichia anomala possesses a unique ability to adapt to and tolerate a number of environmental stresses particularly low pH stress giving it the advantage to outcompete other microorganisms under such conditions. However, the genetic basis of this resistance has not been previously studied.
RESULTS
To this end, we isolated an acid resistant strain of P. anomala, performed a gross phenotypic characterisation at low pH and also performed a whole genome and total RNA sequencing. By integrating the RNA-seq data with the genome sequencing data, we found that several genes associated with different biological processes including proton efflux, the electron transfer chain and oxidative phosphorylation were highly expressed in P. anomala cells grown in low pH media. We therefore present data supporting the notion that a high expression of proton pumps in the plasma membrane coupled with an increase in mitochondrial ATP production enables the high level of acid stress tolerance of P. anomala.
CONCLUSIONS
Our findings provide insight into the molecular and genetic basis of low pH tolerance in P. anomala which was previously unknown. Ultimately, this is a step towards developing non-conventional yeasts such as P. anomala for the production of industrially relevant chemicals under low pH conditions.
Topics: Adenosine Triphosphate; Amino Acid Sequence; Biomass; Electron Transport; Fungal Proteins; Genome, Fungal; Hydrogen-Ion Concentration; Mitochondria; Models, Molecular; Molecular Sequence Data; Oxidative Phosphorylation; Pichia; Sequence Alignment; Sequence Analysis, RNA; Stress, Physiological; Transcriptome
PubMed: 26376644
DOI: 10.1186/s12934-015-0331-4 -
Journal of Applied Microbiology Apr 2008To examine the efficacy of mixed cultures with Saccharomyces cerevisiae and Pichia anomala on flavour profiles of alcoholic beverages, a Pichia mutant with low levels of...
AIM
To examine the efficacy of mixed cultures with Saccharomyces cerevisiae and Pichia anomala on flavour profiles of alcoholic beverages, a Pichia mutant with low levels of ethyl acetate that negatively impact on the sensory quality was isolated.
METHODS AND RESULTS
A petite mutant isolated from P. anomala NBRC 10213 treated with ethidium bromide had the lower activity of ethyl acetate-hydrolysing esterase (EAHase) than the wild-type in crude extracts. In the fermentation tests of pure cultures, the P. anomala mutant produced less ethanol, acetate and ethyl acetate than the wild-type. In mixed cultures with S. cerevisiae, the P. anomala mutant died quicker and produced lower amounts of ethyl acetate than the wild-type. Mixed cultures of S. cerevisiae and P. anomala showed higher activities of EAHase than pure culture of S. cerevisiae throughout the fermentation periods. The transition to the formation of acetate esters was considerably analogous to the transition to the activity of acetate ester-hydrolysing esterase with little time lag.
CONCLUSIONS
The P. anomala mutant was superior to the wild-type in flavour profiles. The higher ethyl acetate concentrations formed mainly by P. anomala in mixed cultures are the primary stimulus for the EAHase in S. cerevisiae and the activity of acetate ester-hydrolysing esterase is crucial to the formation of acetate esters in mixed cultures of S. cerevisiae and P. anomala.
SIGNIFICANCE AND IMPACT OF THE STUDY
An application of non-Saccharomyces yeast, P. anomala to enhance the sensory quality in alcoholic beverage and a mechanism of the formation of acetate esters in mixed cultures with S. cerevisiae and P. anomala were offered.
Topics: Acetates; Esterases; Ethanol; Fermentation; Hydrolysis; Industrial Microbiology; Mutation; Pichia; Saccharomyces cerevisiae; Wine
PubMed: 17976172
DOI: 10.1111/j.1365-2672.2007.03625.x -
Journal of Applied Microbiology Jun 2010Whole cell permeabilization of Pichia anomala to ameliorate the cell-bound phytase activity and usability of permeabilized cells in dephytinization of soymilk.
AIMS
Whole cell permeabilization of Pichia anomala to ameliorate the cell-bound phytase activity and usability of permeabilized cells in dephytinization of soymilk.
METHODS AND RESULTS
The cells of P. anomala were subjected to permeabilization using the surfactant Triton X-100 to overcome the permeability barrier and prepare whole cell biocatalysts with high phytase activity. The statistical approach, response surface methodology (RSM) was used to optimize the operating conditions for permeabilization. The treatment of cells with 5% Triton X-100 for 30 min resulted in c. 15% enhancement in cell-bound phytase activity. The shrinkage of protoplast was observed, although cell viability and phytase stability were not significantly altered. The free as well as immobilized permeabilized cells hydrolysed soymilk phytate, and the latter could be reused over four consecutive cycles.
CONCLUSIONS
Whole cell permeabilization of P. anomala using Triton X-100 led to enhancement in cell-bound phytase activity. The viability and integrity of yeast cells were not significantly affected because of permeabilization. The permeabilized P. anomala cells effectively dephytinized soymilk, and the permeabilized cells immobilized in alginate could be reused because of sustained phytase activity.
SIGNIFICANCE AND IMPACT OF THE STUDY
This is the first report on the use of permeabilized yeast cells for mitigating phytate content of soymilk. Alginate entrapment of permeabilized P. anomala allows reuse of cells for soymilk dephytinization, thus suggesting a potential application in food industry.
Topics: 6-Phytase; Cell Membrane Permeability; Cells, Immobilized; Food Microbiology; Octoxynol; Phytic Acid; Pichia; Soy Milk
PubMed: 19922597
DOI: 10.1111/j.1365-2672.2009.04607.x -
Applied and Environmental Microbiology Oct 2004We investigated the regulation of the central aerobic and hypoxic metabolism of the biocontrol and non-Saccharomyces wine yeast Pichia anomala. In aerobic batch culture,...
We investigated the regulation of the central aerobic and hypoxic metabolism of the biocontrol and non-Saccharomyces wine yeast Pichia anomala. In aerobic batch culture, P. anomala grows in the respiratory mode with a high biomass yield (0.59 g [dry weight] of cells g of glucose(-1)) and marginal ethanol, glycerol, acetate, and ethyl acetate production. Oxygen limitation, but not glucose pulse, induced fermentation with substantial ethanol production and 10-fold-increased ethyl acetate production. Despite low or absent ethanol formation, the activities of pyruvate decarboxylase and alcohol dehydrogenase were high during aerobic growth on glucose or succinate. No activation of these enzyme activities was observed after a glucose pulse. However, after the shift to oxygen limitation, both enzymes were activated threefold. Metabolic flux analysis revealed that the tricarboxylic acid pathway operates as a cycle during aerobic batch culture and as a two-branched pathway under oxygen limitation. Glucose catabolism through the pentose phosphate pathway was lower during oxygen limitation than under aerobic growth. Overall, our results demonstrate that P. anomala exhibits a Pasteur effect and not a Crabtree effect, i.e., oxygen availability, but not glucose concentration, is the main stimulus for the regulation of the central carbon metabolism.
Topics: Acetates; Alcohol Dehydrogenase; Carbon; Citric Acid Cycle; Ethanol; Fermentation; Food Microbiology; Glucose; Kinetics; Models, Biological; Oxygen; Pentose Phosphate Pathway; Pest Control, Biological; Pichia; Pyruvate Decarboxylase; Wine
PubMed: 15466531
DOI: 10.1128/AEM.70.10.5905-5911.2004 -
World Journal of Microbiology &... Nov 2022Yeast mannoproteins are proposed as a paraprobiotics with antimicrobial and prebiotic properties. They can be used as biopreservatives in food and in diseases therapies....
Yeast mannoproteins are proposed as a paraprobiotics with antimicrobial and prebiotic properties. They can be used as biopreservatives in food and in diseases therapies. The knowledge about the specificity and/or capability of their influence on the growth of different microorganism is limited. The study determined the effect of mannoprotein preparations of Saccharomyces cerevisiae (S. cerevisiae) ATCC 7090 and nonconventional yeast origin [Metschnikowia reukaufii (M. reukaufii) WLP 4650 and Wickerhamomyces anomalus (W. anomalus) CCY 38-1-13] on the growth of selected bacteria of the genera: Lactobacilllus, Limosilatobacillus, Limosilatobacillus, Bifidobacterium, Staphylococcus, Enterococcus, Pseudomonas, Escherichia, Proteus and Salmonella. The degree of stimulation or growth inhibition of tested bacteria depended on the type and dose of the mannoprotein and the bacterial strain. The addition of the tested preparations in the entire range of applied concentrations had a positive effect especially on the growth of Lactobacillus arabinosus ATCC 8014 and Bifidobacterium animalis subsp. lactis B12. Mannoproteins isolated from S. cerevisiae limited the growth of the Escherichia coli (E. coli) ATCC 25922, Pseudomonas aureoginosa (P. aureoginosa) ATCC 27853, Proteus mirabilis ATCC 35659 and Salmonella Enteritidis ATCC 13076 to the greatest extent, while preparations of M. reukaufii and W. anomalus origin most effectively limited the growth of Staphylococcus aureus strains, E. coli and P. aureoginosa. The growth of Enterococcus faecalis was stimulated by the presence of all studied preparations in most of the concentrations used. Further research will determine how the purification process of studied mannoproteins or oligosaccharide fractions, its structure and composition influence on the growth of selected bacteria and what is the mechanism of its activity.
Topics: Saccharomyces cerevisiae; Escherichia coli; Phylogeny; Anti-Infective Agents; Anti-Bacterial Agents; Bacteria; Microbial Sensitivity Tests
PubMed: 36319710
DOI: 10.1007/s11274-022-03448-5 -
BMC Microbiology Aug 2023The ascomycetous heterothallic yeast Wickerhamomyces anomalus (WA) has received considerable attention and has been widely reported in the winemaking industry for its...
BACKGROUND
The ascomycetous heterothallic yeast Wickerhamomyces anomalus (WA) has received considerable attention and has been widely reported in the winemaking industry for its distinctive physiological traits and metabolic attributes. An increased concentration of ethanol during ethanol fermentation, however, causes ethanol stress (ES) on the yeast cells. Trehalose has been implicated in improving survival under various stress conditions in microorganisms. Herein, we determined the effects of trehalose supplementation on the survival, differentially expressed genes (DEGs), cellular morphology, and oxidative stress tolerance of WA in response to ES.
RESULTS
The results indicated that trehalose improved the survival and anomalous surface and ultrastructural morphology of WA. Additionally, trehalose improved redox homeostasis by reducing the levels of reactive oxygen species (ROS) and inducing the activities of antioxidant enzymes. In addition, DEGs affected by the application of trehalose were enriched in these categories including in gene expression, protein synthesis, energy metabolism, and cell cycle pathways. Additionally, trehalose increased the content of intracellular malondialdehyde (MDA) and adenosine triphosphate.
CONCLUSIONS
These results reveal the protective role of trehalose in ES mitigation and strengthen the possible uses of WA in the wine fermentation sector.
Topics: Trehalose; Saccharomycetales; Adenosine Triphosphate; Ethanol
PubMed: 37644381
DOI: 10.1186/s12866-023-02982-y -
Microbial Cell Factories Aug 2015Sugar alcohols have been widely applied in the fields of food and medicine owing to their unique properties. Compared to chemical production, microbial production of...
BACKGROUND
Sugar alcohols have been widely applied in the fields of food and medicine owing to their unique properties. Compared to chemical production, microbial production of sugar alcohols has become attractive because of its environmentally friendly and sustainable characteristics. Our previous study identified the nonconventional yeast Pichia anomala TIB-x229 as a potential producer of sugar alcohols from glucose. To further improve strain performance, we combined genome shuffling with optimized high throughput screening methods for the directed improvement of nonconventional yeast and complex phenotypes.
RESULTS
To accelerate strain improvement, a practical genome shuffling procedure was developed and successfully applied in the nonconventional yeast P. anomala to increase sugar alcohol production. Through two rounds of genome shuffling, an improved P. anomala isolate GS2-3 could produce 47.1 g/L total sugar alcohols from 100 g/L glucose, which was 32.3% higher than the original strain. In this process, a simple and accurate colorimetric assay was optimized and used for high throughput screening of sugar alcohol-producing strains. Moreover, a fluorescence-activated cell sorting method was developed to efficiently screen protoplast fusions for genome shuffling of nonconventional yeast.
CONCLUSION
An efficient genome shuffling procedure was developed and applied to enhance the sugar alcohol production of the nonconventional yeast P. anomala. Our results provide a general platform for strain improvement of polyol-producing microorganisms or nonconventional microorganisms in the future.
Topics: DNA Shuffling; Genome, Fungal; Glucose; Pichia; Sugar Alcohols
PubMed: 26246027
DOI: 10.1186/s12934-015-0303-8