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Medical Mycology Oct 2020Antifungal susceptibility profiles of rare Saccharomycotina yeasts remain missing, even though an increase in prevalence of such rare Candida species was reported in...
Antifungal susceptibility profiles of rare Saccharomycotina yeasts remain missing, even though an increase in prevalence of such rare Candida species was reported in candidemia. Majority of these rare yeast species carry intrinsic resistances against at least one antifungal compound. Some species are known to be cross-resistant (against multiple drugs of the same drug class) or even multi-drug resistant (against multiple drugs of different drug classes). We performed antifungal susceptibility testing (AFST) according to EUCAST broth microdilution for 14 rare species (Clavispora lusitaniae, Candida intermedia, Candida auris, Diutina rugosa, Wickerhamiella pararugosa, Yarrowia lipolytica, Pichia norvegensis, Candida nivariensis, Kluyveromyces marxianus, Wickerhamomyces anomalus, Candida palmioleophila, Meyerozyma guilliermondii, Meyerozyma caribbica, and Debaryomyces hansenii) known to cause candidemia. In total, 234 isolates were tested for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, micafungin, and caspofungin. Amphothericin B had the broadest efficiency against the 14 tested rare yeast species, while high minimum inhibitory concentrations (MICs) against azole drugs and echinocandins were common. Voriconazole was the most efficient azole drug. Multidrug resistance was observed for the species C. auris and K. marxianus. Multidrug resistant individual isolates were found for Y. lipolytica and M. caribbica. In conclusion, the observed high MIC values of the rare Saccharomycotina species tested limit antifungal treatment options, complicating the management of such infections.
Topics: Antifungal Agents; Candidemia; Drug Resistance, Fungal; Fluconazole; Humans; Microbial Sensitivity Tests; Saccharomyces; Voriconazole
PubMed: 32043147
DOI: 10.1093/mmy/myaa005 -
Microbial Biotechnology Mar 2020Its features as a microbial and eukaryotic organism have turned Komagataella phaffii (Pichia pastoris) into an emerging cell factory for recombinant protein production...
Its features as a microbial and eukaryotic organism have turned Komagataella phaffii (Pichia pastoris) into an emerging cell factory for recombinant protein production (RPP). As a key step of the bioprocess development, this work aimed to demonstrate the importance of tailor designing the cultivation strategy according to the production kinetics of the cell factory. For this purpose, K. phaffii clones constitutively expressing (P ) Candida rugosa lipase 1 (Crl1) with different gene dosage were used as models in continuous and fed-batch cultures. Production parameters were much greater with a multicopy clone (MCC) than with the single-copy clone (SCC). Regarding production kinetics, the specific product generation rate (q ) increased linearly with increasing specific growth rate (µ) in SCC; by contrast, q exhibited saturation in MCC. A transcriptional analysis in chemostat cultures suggested the presence of eventual post-transcriptional bottlenecks in MCC. After the strain characterization, in order to fulfil overall development of the bioprocess, the performance of both clones was also evaluated in fed-batch mode. Strikingly, different optimal strategies were determined for both models due to the different production kinetic patterns observed as a trade-off for product titre, yields and productivity. The combined effect of gene dosage and adequate µ enables rational process development with a view to optimize K. phaffii RPP bioprocesses.
Topics: Gene Dosage; Pichia; Recombinant Proteins; Saccharomycetales
PubMed: 31657146
DOI: 10.1111/1751-7915.13498 -
G3 (Bethesda, Md.) Dec 2019Infections caused by opportunistic yeast pathogens have increased over the last years. These infections can be originated by a large number of diverse yeast species of...
Infections caused by opportunistic yeast pathogens have increased over the last years. These infections can be originated by a large number of diverse yeast species of varying incidence, and with distinct clinically relevant phenotypic traits, such as different susceptibility profiles to antifungal drugs, which challenge diagnosis and treatment. (syn. ) and (syn. ) are two opportunistic rare yeast pathogens, which low incidence (< 1%) limits available clinical experience. Furthermore, these yeasts have elevated Minimum Inhibitory Concentration (MIC) levels to at least one class of antifungal agents. This makes it more difficult to manage their infections, and thus they are associated with high rates of mortality and clinical failure. With the aim of improving our knowledge on these opportunistic pathogens, we assembled and annotated their genomes. A phylogenomics approach revealed that genes specifically duplicated in each of the two species are often involved in transmembrane transport activities. These genomes and the reconstructed complete catalog of gene phylogenies and homology relationships constitute useful resources for future studies on these pathogens.
Topics: Candida; Genome Size; Genome, Fungal; Genome, Mitochondrial; Phylogeny; Sequence Analysis, DNA
PubMed: 31575637
DOI: 10.1534/g3.119.400762 -
Journal of Nanoscience and... Mar 2020lipase was immobilized in this study using CaCl₂/CMC nanoparticles that yielded a lipase loading capacity of 127 mg/g, with better thermal stability and activity of...
lipase was immobilized in this study using CaCl₂/CMC nanoparticles that yielded a lipase loading capacity of 127 mg/g, with better thermal stability and activity of 91.8%. The hydrolysis of racemic 2-phenylpropionic acid isopropyl ester by free and immobilized lipase was investigated in the mixed organic-solvent composed of isooctane and methyl tert-butyl ether (9.5:0.5, V/V). The optimal conditions were 35 °C and pH 7.5 for free lipase hydrolysis. We obtained ()-2-phenylpropionic acid with 44.85% conversion, 95.75% enantiomeric excess and enantiomeric ratio of 112. The CaCl₂/CMC nanoparticles immobilized lipase possesses high enantioselectivity, with = 237 at 40 °C and pH 7.5. It was efficiently reusable in four cycles and appropriately enhanced enantioselectivity within 120-240.
Topics: Calcium Chloride; Catalysis; Enzymes, Immobilized; Hydrogen-Ion Concentration; Hydrolysis; Lipase; Nanoparticles; Phenylpropionates; Saccharomycetales; Solvents
PubMed: 31492359
DOI: 10.1166/jnn.2020.17343 -
Poultry Science Dec 2019Probiotics are considered the preferred alternatives to antibiotics for growth promotion and disease prevention. Previous studies have confirmed that Diutina rugosa...
Probiotics are considered the preferred alternatives to antibiotics for growth promotion and disease prevention. Previous studies have confirmed that Diutina rugosa SD-17 has the potential as a probiotic. We evaluated the probiotic effect of D. rugosa SD-17 on 360 one-day-old Hy-line brown chickens that were divided into 2 groups, and each group contained 6 replicate pens with 30 birds per pen. The chickens were fed with basal diet supplemented with or without D. rugosa SD-17, and the effects of D. rugosa SD-17 on growth performance, intestine morphology, and immune status were assessed. Body weight was significantly improved from week 3 to 6 (P < 0.05), and the feed conversion ratio was significantly improved in weeks 1 and 2 (P < 0.001). The length of the duodenum was lengthened significantly in week 3 (P < 0.05), and supplementation of D. rugosa SD-17 significantly increased villus height and villus height to crypt depth ratio in the ileum in week 3 (P < 0.05). Expressions of tight-junction-related genes of zonula occludens-2 and occludin in the ileum were significantly increased (P < 0.05). The proliferation capacity of blood lymphocytes stimulated by concanavalin A was significantly enhanced (P < 0.05), and the proportion of helper T (Th) cells increased significantly (P < 0.05). Expressions of Th1 cell markers IL-2 and interferon (IFN)-γ and immune-related genes of IL-1β, transforming growth factor-β, and IFN-γ in ileum were significantly increased (P < 0.05). These results indicated that D. rugosa SD-17 improved the growth and regulated immunity of chickens, and could be optimized for use as a feed additive for livestock and poultry.
Topics: Animal Feed; Animals; Chickens; Diet; Intestines; Probiotics; Random Allocation; Saccharomycetales
PubMed: 31350991
DOI: 10.3382/ps/pez428 -
The Journal of Antimicrobial... Sep 2019To generate antifungal susceptibility patterns for Trichomonascus ciferrii (Candida ciferrii), Candida inconspicua (Torulopsis inconspicua) and Diutina rugosa species...
OBJECTIVES
To generate antifungal susceptibility patterns for Trichomonascus ciferrii (Candida ciferrii), Candida inconspicua (Torulopsis inconspicua) and Diutina rugosa species complex (Candida rugosa species complex), and to provide key parameters such as MIC50, MIC90 and tentative epidemiological cut-off values (TECOFFs).
METHODS
Our strain set included isolates of clinical origin: C. inconspicua (n = 168), D. rugosa species complex (n = 90) [Candida pararugosa (n = 60), D. rugosa (n = 26) and Candida mesorugosa (n = 4)], Pichia norvegensis (Candida norvegensis) (n = 15) and T. ciferrii (n = 8). Identification was performed by MALDI-TOF MS or internal transcribed spacer sequencing. Antifungal susceptibility patterns were generated for azoles, echinocandins and amphotericin B using commercial Etest and the EUCAST broth microdilution method v7.3.1. Essential agreement (EA) was calculated for Etest and EUCAST.
RESULTS
C. inconspicua, C. pararugosa and P. norvegensis showed elevated azole MICs (MIC50 ≥0.06 mg/L), and D. rugosa and C. pararugosa elevated echinocandin MICs (MIC50 ≥0.06 mg/L). EA between methods was generally low (<90%); EA averaged 77.45%. TECOFFs were suggested for C. inconspicua and D. rugosa species complex.
CONCLUSIONS
Rare yeast species tested shared high fluconazole MICs. D. rugosa species complex displayed high echinocandin MICs, while C. inconspicua and P. norvegensis were found to have high azole MICs. Overall, the agreement between EUCAST and Etest was poor and therefore MIC values generated with Etest cannot be directly compared with EUCAST results.
Topics: Antifungal Agents; Ascomycota; Humans; Microbial Sensitivity Tests; Mycoses; Sensitivity and Specificity
PubMed: 31203366
DOI: 10.1093/jac/dkz231 -
Mycologia 2019Opportunistic mycoses by yeasts have increased considerably in the last three decades. Although is considered one of the most important causes of nosocomial infections,... (Comparative Study)
Comparative Study Review
Opportunistic mycoses by yeasts have increased considerably in the last three decades. Although is considered one of the most important causes of nosocomial infections, there is a recent shift to non- species as the most frequently isolated yeasts in particular risk groups. (formerly ) is a complex that includes four species: sensu stricto, , and , and they are estimated to represent 0.2% of all clinical isolates. In this study, we analyze nine clinical isolates of with focus on the virulence determinants and pathogenicity of the species by means of a survival model. Overall, we detected very strong aspartyl-protease and esterase activities. In contrast, both DNase and hemolysin activities were evident in only two of the isolates. None of the isolates was positive for phospholipase activity. All isolates studied were able to form biofilm after 72 h of incubation in a robust manner when compared with the strain used as control. Susceptibility testing showed minimum inhibitory concentrations (MICs) ≤1 µg/mL for amphotericin B in all isolates tested. Eight out of nine of the isolates had MICs ≤2 µg/mL for fluconazole. All isolates were resistant to both anidulafungin and caspofungin (MICs ≥1 µg/mL). We found a significant difference ( < 0.0001) amongst the survival curves for the different isolates in the survival model. Strains HPM309 and H259 produced an acute infection and exhibited the highest virulence, whereas the isolates 99-480 and DM17 proved to be the less virulent strains.
Topics: Animals; Antifungal Agents; Biofilms; Candida; Candidiasis; DNA, Fungal; Drug Resistance, Multiple, Fungal; Larva; Moths; Phylogeny; Virulence; Virulence Factors
PubMed: 30985256
DOI: 10.1080/00275514.2019.1585161 -
Journal de Mycologie Medicale Jun 2019Candida rugosa (recently reclassified Diutina rugosa) is an emerging pathogen affecting humans and animals. Candida resistance to existing drugs is an important factor...
Candida rugosa (recently reclassified Diutina rugosa) is an emerging pathogen affecting humans and animals. Candida resistance to existing drugs is an important factor to be monitored, as well as the need of researching alternatives to conventional antifungals. Here, we evaluated the in vitro effects of some antifungals and major components of essential oils by the broth microdilution method (CLSI M27-A3) against fifteen C. rugosa strains from animals isolated and molecular identificated. The results showed MIC of: 0.125μg/mL to ketoconazole and voriconazole, 0.25μg/mL to micafungin, 0.5μg/mL to anidulafungin, 1μg/mL to caspofungin, 2μg/mL to amphotericin B, itraconazole and flucytosin, 8μg/mL to fluconazole, 16μg/mL to nystatin and >128μg/mL to terbinafine. The compounds carvacrol (MIC 320μg/mL), thimol (MIC 320μg/mL) and cinnamaldehyde (MIC 160μg/mL) demonstrated antifungal activity against the samples tested.
Topics: Acrolein; Anidulafungin; Animals; Antifungal Agents; Candida; Caspofungin; Cattle; Dogs; Horses; Micafungin; Microbial Sensitivity Tests; Oils, Volatile
PubMed: 30956064
DOI: 10.1016/j.mycmed.2019.03.002 -
Applied Microbiology and Biotechnology Mar 2019Asian cold-based glacier yeasts with respect to their abundance, distribution, and taxonomy, in contrast to other continental cryosphere areas, have been little...
Asian cold-based glacier yeasts with respect to their abundance, distribution, and taxonomy, in contrast to other continental cryosphere areas, have been little investigated. The present study reports the diversity and phylogeny of culturable cold-adapted yeasts in six cold habitats of the Glacier No.1 in the Tianshan Mountains (northwestern China). Of the total 591 yeast isolates, 401 were identified as basidiomycetous yeasts represented by 41 species of 15 genera, while 190 ascomycetous yeast isolates were assigned to the 8 species of 7 genera. The most prevalent species was Candida akabanensis with a 19.8% frequency of occurrence, followed by Vishniacozyma victoriae (16.4%) and Diutina rugosa (9.98%), of which V. victoriae was the only yeast species common to all six glacial habitats. Variability on the component and abundance of yeast taxa among glacial habitats primarily displayed in four dominant yeast genera, namely Candida, Vishniacozyma, Filobasidium, and Naganishia. However, network analysis illustrated that most of 32 rare yeast populations were habitat-specific, implying that the low-abundance yeast population was more easily influenced by the local habitat conditions (species sorting). Based on indicator species analyses, the subglacial habitat was characterized by psychrotolerant and/or psychrophilic yeast taxa.
Topics: Adaptation, Physiological; Basidiomycota; Biodiversity; Candida; China; Cold Temperature; DNA, Intergenic; Ecosystem; Ice Cover; Phylogeny; Saccharomycetales; Yeasts
PubMed: 30483846
DOI: 10.1007/s00253-018-9512-5 -
Diagnostic Microbiology and Infectious... Sep 2016Echinocandins are recommended as a first-line therapy for invasive candidiasis. Candida rugosa was recently transferred to the new genus Diutina. We have determined the...
Echinocandins are recommended as a first-line therapy for invasive candidiasis. Candida rugosa was recently transferred to the new genus Diutina. We have determined the in vitro killing kinetics of two echinocandins, anidulafungin, and caspofungin and their in vivo efficacy, administering doses of 5 or 10 mg/kg, and 1 or 5 mg/kg, respectively against 2 clinical strains of D. rugosa. Both drugs showed a fungicidal concentration-dependent activity and, in a neutropenic murine model of disseminated infection, were able to reduce tissue burden and to prolong survival of mice. These results suggest that both echinocandins could be useful to treat infections by this fungus when isolates show minimal inhibitory concentrations within the range of susceptibility for both drugs.
Topics: Anidulafungin; Animal Structures; Animals; Antifungal Agents; Caspofungin; Colony Count, Microbial; Disease Models, Animal; Echinocandins; Fungemia; Lipopeptides; Male; Mice; Saccharomycetales; Survival Analysis; Treatment Outcome
PubMed: 27342787
DOI: 10.1016/j.diagmicrobio.2016.05.014