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PLoS Pathogens Oct 2020First described in 2009 in Japan, the emerging multidrug-resistant fungal pathogen Candida auris is becoming a worldwide public health threat that has been attracting... (Review)
Review
First described in 2009 in Japan, the emerging multidrug-resistant fungal pathogen Candida auris is becoming a worldwide public health threat that has been attracting considerable attention due to its rapid and widespread emergence over the past decade. The reasons behind the recent emergence of this fungus remain a mystery to date. Genetic analyses indicate that this fungal pathogen emerged simultaneously in several different continents, where 5 genetically distinct clades of C. auris were isolated from distinct geographical locations. Although C. auris belongs to the CTG clade (its constituent species translate the CTG codon as serine instead of leucine, as in the standard code), C. auris is a haploid fungal species that is more closely related to the haploid and often multidrug-resistant species Candida haemulonii and Candida lusitaniae and is distantly related to the diploid and clinically common fungal pathogens Candida albicans and Candida tropicalis. Infections and outbreaks caused by C. auris in hospitals settings have been rising over the past several years. Difficulty in its identification, multidrug resistance properties, evolution of virulence factors, associated high mortality rates in patients, and long-term survival on surfaces in the environment make C. auris particularly problematic in clinical settings. Here, we review progress made over the past decade on the biological and clinical aspects of C. auris. Future efforts should be directed toward understanding the mechanistic details of its biology, epidemiology, antifungal resistance, and pathogenesis with a goal of developing novel tools and methods for the prevention, diagnosis, and treatment of C. auris infections.
Topics: Antifungal Agents; Candida; Candidiasis; Drug Resistance, Fungal; Humans; Saccharomycetales; Virulence
PubMed: 33091071
DOI: 10.1371/journal.ppat.1008921 -
Open Forum Infectious Diseases Jan 2023Fungal species have undergone and continue to undergo significant nomenclatural change, primarily due to the abandonment of dual species nomenclature in 2013 and the... (Review)
Review
Fungal species have undergone and continue to undergo significant nomenclatural change, primarily due to the abandonment of dual species nomenclature in 2013 and the widespread application of molecular technologies in taxonomy allowing correction of past classification errors. These have effected numerous name changes concerning medically important species, but by far the group causing most concern are the yeasts. Among common species, , , , , and have been changed to , , , , and , respectively. There are currently no guidelines for microbiology laboratories on implementing changes, and there is ongoing concern that clinicians will dismiss or misinterpret laboratory reports using unfamiliar species names. Here, we have outlined the rationale for name changes across the major groups of clinically important fungi and have provided practical recommendations for managing change.
PubMed: 36632423
DOI: 10.1093/ofid/ofac559 -
Microbiology Spectrum Dec 2022In recent decades, the incidence of infections has increased in immunocompromised patients. This multicenter study aimed to evaluate antifungal activities of 8...
In recent decades, the incidence of infections has increased in immunocompromised patients. This multicenter study aimed to evaluate antifungal activities of 8 antifungal agents against the species isolated from 10 university hospitals in Iran. During the period from Dec 2019 to Dec 2021, species were collected from clinical samples of patients. The isolates were identified by PCR restriction fragment length polymorphism and sequencing methods. The antifungal susceptibility tests of each isolate to eight antifungal agents were performed according to the microdilution CLSI M27, M59, and M60 standard methods. A total of 598 strains were isolated from clinical samples. The most commonly isolated species was C. albicans, followed by C. glabrata, C. parapsilosis, Debaryomyces hansenii (Candida famata), C. tropicalis, (Candida krusei), C. orthopsilosis, Meyerozyma guilliermondii (Candida guilliermondii), Kluyveromyces marxianus (Candida kefyr), and Clavispora lusitaniae (Candida lusitaniae). MIC values in all species were as follows: 0.25 μg/mL for caspofungin and voriconazole; 0.5 μg/mL for amphotericin B and isavuconazole; 2 μg/mL for itraconazole, luliconazole, and posaconazole; and 16 μg/mL for fluconazole. Although 30/285 C. albicans, 15/31 3/12 , 67/125 C. glabrata, 5/15 , 6/60 C. parapsilosis, and 5/23 C. tropicalis isolates were multiazole resistant with resistance to 2 to 4 azoles, pan-azole resistance was not observed. According to our data, Candida albicans and C. glabrata were the most frequent species isolated from clinical samples in Iran. Caspofungin and voriconazole, with lower MIC values, are the most effective than other antifungal agents for the treatment of infections in this region. species cause severe invasive infections of the heart, brain, eyes, bones, and other parts of the body. Knowledge of regional distributions of causative agents and their antifungal susceptibility patterns can help to monitor resistance to antifungal agents of various species and support local and national surveillance programs. In the present study, C. albicans and C. glabrata were the most frequently isolated species from clinical samples in Iran. Increasing rates of non- isolates from the Iranian population should be looked at as alarming due to various levels of intrinsic MIC values or resistance to various antifungal drugs. Caspofungin and voriconazole are recommended over fluconazole for the treatment of infections in the study region. However, amphotericin B and isavuconazole are also active against the most common species isolated from patients. Pan azole-resistant species were not observed in the present study.
Topics: Humans; Amphotericin B; Antifungal Agents; Azoles; Candida; Candida albicans; Candida glabrata; Candidiasis; Caspofungin; Drug Resistance, Fungal; Fluconazole; Iran; Microbial Sensitivity Tests; Tertiary Care Centers; Voriconazole
PubMed: 36445122
DOI: 10.1128/spectrum.02453-22 -
PloS One 2020Only quite recently, we have shown that yeast strains Clavispora lusitaniae 146 and Pichia fermentans 27 can act as efficient biocontrol agents for combating postharvest...
Only quite recently, we have shown that yeast strains Clavispora lusitaniae 146 and Pichia fermentans 27 can act as efficient biocontrol agents for combating postharvest fungal diseases in lemons. During postharvest and storage conditions, microorganisms are subject to different stress factors that could affect both their survival and their protective capacity. Understanding the tolerance of yeasts to environmental stress factors could support the future development and commercial application of biological control formulations based on such organisms. Thus, the impact of different stressors on the viability and protection efficiency of C. lusitaniae strain 146 and P. fermentans strain 27 was evaluated, and the yeasts were subjected to oxidative stress, thermal treatments, exposure to NaOCl, osmotic stress, and ultraviolet irradiation. Candida oleophila strain O served as the reference control. C. lusitaniae 146 was more resistant to H2O2 in plate assays; however, in liquid media there was no significant difference to the other strains. Strain 146 was less affected by NaOCl, being able to survive with 300 ppm. P. fermentans 27 was the strain most heavily affected by osmotic pressure, while strains 146 and strain O showed a similar adaptation. UV-B irradiation severely affected C. oleophila and P. fermentans, while C. lusitaniae was the most resistant. Strains 146 and 27 were similarly tolerant to thermal shocks, compared to the reference strain, which was less viable. In in vivo tests, exposure to 10 mM H2O2, 45°C or 200 ppm NaOCl prior to fruit inoculation, reduced the antagonistic activity against the pathogen Penicillium digitatum. However, in no case was the biocontrol efficiency reduced to less than 50%. As C. lusitaniae 146 demonstrated a great potential to combat P. digitatum under a wide range of conditions, the organism is a promising candidate as an effective and valuable alternative to toxic fungicides.
Topics: Citrus; Microbial Viability; Oxidative Stress; Pest Control, Biological; Saccharomycetales; Temperature
PubMed: 32946508
DOI: 10.1371/journal.pone.0239432 -
Microorganisms Jan 2024Emerging life-threatening multidrug-resistant (MDR) species such as the species complex, (sin. ), and other species are considered as an increasing risk for human...
Emerging life-threatening multidrug-resistant (MDR) species such as the species complex, (sin. ), and other species are considered as an increasing risk for human health in the near future. (1) Background: Many studies have emphasized that the increase in drug resistance can be associated with several virulence factors in and its knowledge is also essential in developing new antifungal strategies. (2) Methods: Hydrophobicity, adherence, biofilm formation, lipase activity, resistance to osmotic stress, and virulence 'in vivo' on larvae were studied in isolates of , , and with low susceptibility and resistance to fluconazole and amphotericin B. (3) Results: Intra- and interspecies variability were observed. showed high hydrophobicity and the ability to adhere to and form biofilm. was less hydrophobic, was biofilm-formation-strain-dependent, and did not show lipase activity. Larvae inoculated with isolates displayed significantly higher mortality rates than those infected with and . (4) Conclusions: The ability to adhere to and form biofilms associated with their hydrophobic capacity, to adapt to stress, and to infect within an in vivo model, observed in these non-wild-type and isolates, shows their marked virulence features. Since factors that define virulence are related to the development of the resistance of these fungi to the few antifungals available for clinical use, differences in the physiology of these cells must be considered to develop new antifungal therapies.
PubMed: 38276197
DOI: 10.3390/microorganisms12010212 -
MBio Mar 2021The evolution of pathogens in response to selective pressures present during chronic infections can influence their persistence and virulence and the outcomes of...
The evolution of pathogens in response to selective pressures present during chronic infections can influence their persistence and virulence and the outcomes of antimicrobial therapy. Because subpopulations within an infection can be spatially separated and the host environment can fluctuate, an appreciation of the pathways under selection may be most easily revealed through the analysis of numerous isolates from single infections. Here, we continued our analysis of a set of clonally derived () isolates from a single chronic lung infection with a striking enrichment in the number of alleles of Genetic and genomic analyses found evidence for repeated acquisition of gain-of-function mutations that conferred constitutive Mrr1 activity. In the same population, there were multiple alleles with both gain-of-function mutations and secondary suppressor mutations that either attenuated or abolished the constitutive activity, suggesting the presence of counteracting selective pressures. Our studies demonstrated trade-offs between high Mrr1 activity, which confers resistance to the antifungal fluconazole, host factors, and bacterial products through its regulation of , and resistance to hydrogen peroxide, a reactive oxygen species produced in the neutrophilic environment associated with this infection. This inverse correlation between high Mrr1 activity and hydrogen peroxide resistance was observed in multiple species and in serially collected populations from this individual over 3 years. These data lead us to propose that dynamic or variable selective pressures can be reflected in population genomics and that these dynamics can complicate the drug resistance profile of the population. Understanding microbial evolution within patients is critical for managing chronic infections and understanding host-pathogen interactions. Here, our analysis of multiple alleles in isolates from a single () infection revealed the selection for both high and low Mrr1 activity. Our studies reveal trade-offs between high Mrr1 activity, which confers resistance to the commonly used antifungal fluconazole, host antimicrobial peptides, and bacterial products, and resistance to hydrogen peroxide. This work suggests that spatial or temporal differences within chronic infections can support a large amount of dynamic and parallel evolution and that Mrr1 activity is under both positive and negative selective pressure to balance different traits that are important for microbial survival.
Topics: Antifungal Agents; Biological Evolution; Drug Resistance, Fungal; Fluconazole; Fungal Proteins; Gene Expression Regulation, Fungal; Humans; Microbial Sensitivity Tests; Mutation; Mycoses; Saccharomycetales
PubMed: 33785623
DOI: 10.1128/mBio.03328-20 -
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 -
The Journal of Biological Chemistry Aug 1990The cellular location of beta-1,4-glucosidase activity from, as well as the transport of glucose and cellobiose into, cells of Clavispora lusitaniae NRRL Y-5394 and... (Comparative Study)
Comparative Study
The cellular location of beta-1,4-glucosidase activity from, as well as the transport of glucose and cellobiose into, cells of Clavispora lusitaniae NRRL Y-5394 and Candida wickerhamii NRRL Y-2563 was investigated. The beta-glucosidase from Cl. lusitaniae appeared to be a soluble cytoplasmic enzyme. This yeast transported both glucose and cellobiose when grown in medium containing cellobiose as the sole carbon source. Glucose, but not cellobiose, uptake was observed for cells grown on glucose. The Ks and Vmax values for cellobiose transport were different when Cl. lusitaniae was cultured either aerobically (0.11 mM, 6.28 nmol.min-1.mg-1) or anaerobically (0.25 mM, 3.88 nmol-1.min-1.mg-1). The Ks and Vmax values for glucose transport (0.23-1.10 mM and 17.2-33.9 nmol.min-1.mg-1) also differed with the various growth conditions. The beta-glucosidase from C. wickerhamii was extracytoplasmically located. This yeast transported glucose, but not cellobiose, under all growth conditions tested. The Ks for glucose uptake was 0.13-0.28 mM when C. wickerhamii was cultured on cellobiose and 0.25-0.30 mM when cultured on glucose. The Vmax values for glucose uptake were greater for cells cultured on cellobiose (35.0-37.9 nmol.min-1.mg-1) than for cells cultured on glucose (15.6-21.4 nmol.min-1.mg-1). Cellobiose did not inhibit glucose uptake in either yeast. Glucose partially inhibited cellobiose transport in C. lusitaniae, but only if the yeast was grown aerobically. In both yeasts, sugar transport was sensitive to carbonyl cyanide p-trifluoromethoxyphenylhydrazone and 1799, but insensitive to valinomycin.
Topics: Aerobiosis; Anaerobiosis; Biological Transport; Candida; Cellobiose; Disaccharides; Glucose; Kinetics; Models, Biological; Saccharomycetales; Species Specificity; beta-Glucosidase
PubMed: 2115884
DOI: No ID Found -
Microorganisms Sep 2020Fungal rots are one of the main causes of large economic losses and deterioration in the quality and nutrient composition of fruits during the postharvest stage. The...
Fungal rots are one of the main causes of large economic losses and deterioration in the quality and nutrient composition of fruits during the postharvest stage. The yeast 146 has previously been shown to efficiently protect lemons from green mold caused by . In this work, the effect of yeast concentration and exposure time on biocontrol efficiency was assessed; the protection of various citrus fruits against by 146 was evaluated; the ability of strain 146 to degrade mycotoxin patulin was tested; and the effect of the treatment on the sensory properties of fruits was determined. An efficient protection of lemons was achieved after minimum exposure to a relatively low yeast cell concentration. Apart from lemons, the yeast prevented green mold in grapefruits, mandarins, oranges, and tangerines, implying that it can be used as a broad-range biocontrol agent in citrus. The ability to degrade patulin indicated that strain 146 may be suitable for the control of further species. Yeast treatment did not alter the sensory perception of the aroma of fruits. These results corroborate the potential of 146 for the control of postharvest diseases of citrus fruits and indicate its suitability for industrial-scale fruit processing.
PubMed: 32993018
DOI: 10.3390/microorganisms8101477 -
Botanical Studies May 2022Potato taste defect (PTD) of coffee is characterized by a raw potato like smell that leads to a lower quality taste in the brewed coffee, and harms the commercial value...
BACKGROUND
Potato taste defect (PTD) of coffee is characterized by a raw potato like smell that leads to a lower quality taste in the brewed coffee, and harms the commercial value of some East African coffees. Although several causes for PTD have been proposed, none of them have been confirmed. Recently, high throughput sequencing techniques and bioinformatic analysis have shown great potential for identifying putative causal agents of plant diseases. Toward the goal of determining the cause of PTD, we examined raw coffee beans from Rwanda exhibiting varying PTD scores using an Illumina-based sequence analysis of the fungal rRNA ITS region.
RESULTS
Six fungal amplicon sequence variants (ASVs) with high relative abundances correlated with coffee taste scores. Four of these ASVs exhibited negative correlations - Aspergillus versicolor, Penicillium cinnamopurpureum, Talaromyces radicus, and Thermomyces lanuginosus - indicating that they might be causing PTD. Two of these fungi exhibited positive correlations - Kazachstania humilis and Clavispora lusitaniae - indicating that they might be inhibiting organisms that cause PTD.
CONCLUSIONS
This study addressed PTD causality from a new angle by examining fungi with high throughput sequencing. To our knowledge, this is the first study characterizing fungi associated with PTD, providing candidates for both causality and biocontrol.
PubMed: 35604510
DOI: 10.1186/s40529-022-00346-9