RESUMO
In response to the growing global threat of fungal infections, in 2020 the World Health Organisation (WHO) established an Expert Group to identify priority fungi and develop the first WHO fungal priority pathogen list (FPPL). The aim of this systematic review was to evaluate the features and global impact of invasive infections caused by Pichia kudriavzevii (formerly known as Candida krusei). PubMed and Web of Science were used to identify studies published between 1 January 2011 and 18 February 2021 reporting on the criteria of mortality, morbidity (defined as hospitalisation and length of stay), drug resistance, preventability, yearly incidence, and distribution/emergence. Overall, 33 studies were evaluated. Mortality rates of up to 67% in adults were reported. Despite the intrinsic resistance of P. kudriavzevii to fluconazole with decreased susceptibility to amphotericin B, resistance (or non-wild-type rate) to other azoles and echinocandins was low, ranging between 0 and 5%. Risk factors for developing P. kudriavzevii infections included low birth weight, prior use of antibiotics/antifungals, and an underlying diagnosis of gastrointestinal disease or cancer. The incidence of infections caused by P. kudriavzevii is generally low (â¼5% of all Candida-like blood isolates) and stable over the 10-year timeframe, although additional surveillance data are needed. Strategies targeting the identified risk factors for developing P. kudriavzevii infections should be developed and tested for effectiveness and feasibility of implementation. Studies presenting data on epidemiology and susceptibility of P. kudriavzevii were scarce, especially in low- and middle-income countries (LMICs). Thus, global surveillance systems are required to monitor the incidence, susceptibility, and morbidity of P. kudriavzevii invasive infections to inform diagnosis and treatment. Timely species-level identification and susceptibility testing should be conducted to reduce the high mortality and limit the spread of P. kudriavzevii in healthcare facilities.
Assuntos
Antifúngicos , Farmacorresistência Fúngica , Pichia , Organização Mundial da Saúde , Humanos , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Pichia/isolamento & purificação , Pichia/efeitos dos fármacos , Incidência , Fatores de Risco , Candidíase/epidemiologia , Candidíase/microbiologia , Candidíase/prevenção & controleRESUMO
Yeasts are unicellular eukaryotic microorganisms extensively employed in various applications, notably as an alternative source of protein in feeds, owing to their nutritional benefits. Despite their potential, marine and mangrove yeast species used in the aquaculture industry have received little attention in the Philippines. Pichia kudriavzevii (A2B R1 ISO 3), sourced from bark samples, was selected and mass-produced due to its high protein content and amino acid profile. The dried biomass of P. kudriavzevii was incorporated into the diets of Nile tilapia (Oreochromis niloticus) juveniles at varying inclusion levels (0, 1, 2, and 4 g/kg diet) and its effect on their growth performance, body composition, and liver and intestinal morphology was assessed after 40 days of feeding. The groups that received P. kudriavzevii at a concentration of 2 g/kg diet exhibited higher final body weight, percent weight gain, and specific growth rate in comparison to the other treatment groups. Whole body proximate composition did not vary among the dietary groups. Intestinal and liver histopathology also indicated no abnormalities. These findings suggest the potential of ascomycetous P. kudriavzevii as a beneficial feed additive in Nile tilapia diets, warranting further investigation into its long-term effects and broader applications in fish culture.
Assuntos
Ração Animal , Aquicultura , Ciclídeos , Pichia , Animais , Ração Animal/análise , Ciclídeos/crescimento & desenvolvimento , Ciclídeos/microbiologia , Pichia/crescimento & desenvolvimento , Pichia/isolamento & purificação , Pichia/metabolismo , Dieta/veterinária , Fígado/microbiologia , Intestinos/microbiologia , Suplementos Nutricionais/análise , FilipinasRESUMO
Yeast, which plays a pivotal role in the brewing, food, and medical industries, exhibits a close relationship with human beings. In this study, we isolated and purified 60 yeast strains from the natural fermentation broth of Sidamo coffee beans to screen for indigenous beneficial yeasts. Among them, 25 strains were obtained through morphological characterization on nutritional agar medium from Wallerstein Laboratory (WL), with molecular biology identifying Saccharomyces cerevisiae strain YBB-47 and the remaining 24 yeast strains identified as Pichia kudriavzevii. We investigated the fermentation performance, alcohol tolerance, SO2 tolerance, pH tolerance, sugar tolerance, temperature tolerance, ester production capacity, ethanol production capacity, H2S production capacity, and other brewing characteristics of YBB-33 and YBB-47. The results demonstrated that both strains could tolerate up to 3% alcohol by volume at a high sucrose mass concentration (400 g/L) under elevated temperature conditions (40 â), while also exhibiting a remarkable ability to withstand an SO2 mass concentration of 300 g/L at pH 3.2. Moreover, S. cerevisiae YBB-47 displayed a rapid gas production rate and strong ethanol productivity. whereas P. kudriavzevii YBB-33 exhibited excellent alcohol tolerance. Furthermore, this systematic classification and characterization of coffee bean yeast strains from the Sidamo region can potentially uncover additional yeasts that offer high-quality resources for industrial-scale coffee bean production.
Assuntos
Etanol , Fermentação , Pichia , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/isolamento & purificação , Pichia/metabolismo , Pichia/isolamento & purificação , Pichia/genética , Pichia/classificação , Etanol/metabolismo , Concentração de Íons de Hidrogênio , Café/microbiologia , Coffea/microbiologia , Temperatura , Sementes/microbiologia , Sulfeto de Hidrogênio/metabolismoRESUMO
Fungemia is common in critically ill patient populations, and is associated with a high rate of mortality, especially when caused by nonalbicans Candida species. Herein, we describe a fatal case of fungemia following cardiothoracic surgery in which the organism, initially identified as Candida inconspicua, represents a novel species: Pichia alaskaensis.
Assuntos
Fungemia , Pichia , Humanos , Fungemia/microbiologia , Fungemia/diagnóstico , Evolução Fatal , Pichia/isolamento & purificação , Masculino , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Antifúngicos/uso terapêutico , Idoso , Pessoa de Meia-Idade , FemininoRESUMO
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.
Assuntos
Biodiversidade , Frutas , Vitis , Leveduras , China , Fazendas , Fermentação , Frutas/microbiologia , Hanseniaspora/classificação , Hanseniaspora/isolamento & purificação , Pichia/classificação , Pichia/isolamento & purificação , Saccharomycetales/classificação , Saccharomycetales/isolamento & purificação , Vitis/microbiologia , Vinho/microbiologia , Leveduras/classificação , Leveduras/isolamento & purificaçãoRESUMO
Bactrocera tryoni (Froggatt), the Queensland fruit fly (Qfly), is a highly polyphagous tephritid fly that is widespread in Eastern Australia. Qfly physiology is closely linked with its fungal associates, with particular relationship between Qfly nutrition and yeast or yeast-like fungi. Despite animal-associated fungi typically occurring in multi-species communities, Qfly studies have predominately involved the culture and characterisation of single fungal isolates. Further, only two studies have investigated the fungal communities associated with Qfly, and both have used culture-dependant techniques that overlook non-culturable fungi and hence under-represent, and provide a biased interpretation of, the overall fungal community. In order to explore a potentially hidden fungal diversity and complexity within the Qfly mycobiome, we used culture-independent, high-throughput Illumina sequencing techniques to comprehensively, and holistically characterized the fungal community of Qfly larvae and overcome the culture bias. We collected larvae from a range of fruit hosts along the east coast of Australia, and all had a mycobiome dominated by ascomycetes. The most abundant fungal taxa belonged to the genera Pichia (43%), Candida (20%), Hanseniaspora (10%), Zygosaccharomyces (11%) and Penicillium (7%). We also characterized the fungal communities of fruit hosts, and found a strong degree of overlap between larvae and fruit host communities, suggesting that these communities are intimately inter-connected. Our data suggests that larval fungal communities are acquired from surrounding fruit flesh. It is likely that the physiological benefits of Qfly exposure to fungal communities is primarily due to consumption of these fungi, not through syntrophy/symbiosis between fungi and insect 'host'.
Assuntos
Frutas/microbiologia , Interações entre Hospedeiro e Microrganismos/fisiologia , Larva/microbiologia , Micobioma/fisiologia , Simbiose , Tephritidae/microbiologia , Animais , Ascomicetos/isolamento & purificação , Ascomicetos/fisiologia , Austrália , Candida/isolamento & purificação , Candida/fisiologia , Hanseniaspora/isolamento & purificação , Hanseniaspora/fisiologia , Penicillium/isolamento & purificação , Penicillium/fisiologia , Pichia/isolamento & purificação , Pichia/fisiologia , Zygosaccharomyces/isolamento & purificação , Zygosaccharomyces/fisiologiaRESUMO
Cabernet Sauvignon grape produced in Xinjiang (China) is often overripe, with unusually high sugar content, which impedes utilization. We aimed to establish the optimal combination of indigenous yeast strains to produce a new sweet wine from the overripe grape. Five yeast strains with pronounced enological characteristics were selected from 88 indigenous yeast isolates. Using a series of co-fermentation experiments with different inoculated strategies, we achieved optimal co-fermentation with a combination of strains SC19 and NS68, later identified as Saccharomyces cerevisiae and Pichia kudriavzevii, respectively, simultaneously inoculated in a 1:1 ratio at the early stage of fermentation. The combination was characterized by vigorous fermentation with high resistance to 457.13 g/L sugar and high alcohol yield (16.01% vol). The sweet wine contained 17 aromatic compounds with odor activity value (OAV) ≥ 1 and pronounced sweet fruit, floral, herbaceous, and caramel odors. The co-fermentation has a good potential for utilization of overripe Cabernet Sauvignon grape.
Assuntos
Vinho/análise , Vinho/microbiologia , Leveduras/isolamento & purificação , Leveduras/metabolismo , China , Fermentação , Odorantes/análise , Pichia/isolamento & purificação , Pichia/metabolismo , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/metabolismo , Paladar , VitisRESUMO
To investigate the yeast population dynamics during air exposure in total mixed ration (TMR) silage containing sweet potato residue. TMR were ensiled in laboratory silos (1 kg) with or without two lactic acid bacteria strains, Lactobacillus plantarum (LP), and Lactobacillus amylovorus (LA). Fermentation characteristics were measured and yeast population was investigated by ITS1 region gene sequencing using Illumina MiSeq platform. All treatments were well ensiled, and L. amylovorus improved aerobic stability. During aerobic exposure, Pichia kudriavzevii was detected with increased relative abundance in all treatments and more relative abundant in LP. Pichia fermentans was more relative abundant in control. Higher relative abundance of Pichia anomala was detected in deteriorating LP. The relative abundance of Pichia ohmeri increased during later aerobic exposure in the control and LA, with a significant increase in the count of yeast population. Despite Cryptococcus was detected more relative abundant during early stage of aerobic exposure, the yeast population was below the detection limit. Aerobic deterioration was characterized by an increase in operational taxonomic units of Pichia. High relative abundance of P. anomala and P. kudriavzevii made aerobic deterioration easier. Inhibition of P. fermentans might be an effective strategy for improving the aerobic stability to some instance.
Assuntos
Ar , Reatores Biológicos , Dieta/veterinária , Fermentação , Ipomoea batatas , Pichia/isolamento & purificação , Silagem/microbiologia , Aerobiose , Cryptococcus/isolamento & purificação , Microbiologia de Alimentos , Qualidade dos Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillus acidophilus , Lactobacillus plantarumRESUMO
O herpesvírus equídeo 1 (EHV-1) apresenta distribuição mundial e causa graves prejuízos à equideocultura. É agente de surtos de doença respiratória, reprodutiva e neurológica, em equídeos jovens e adultos. A glicoproteína D (gD) do envelope viral é essencial para ligação e penetração em células permissivas e direcionamento do sistema imunológico do hospedeiro, induz respostas imunes humorais e celulares, sendo um antígeno apropriado para ser utilizado em vacinas e imunodiagnóstico. O objetivo deste trabalho foi expressar e caracterizar a gD do EHV-1 em Pichia pastoris para posterior utilização como antígeno em técnicas de imunodiagnóstico e formulação de vacinas recombinantes. Uma sequência de DNA que codifica uma forma truncada da gDEHV-1 foi clonada no vetor pPICZαA de expressão em P. pastoris. Obteve-se uma proteína de ~41 kDa, como esperado. A proteína apresentou glicosilação entre 4 kDa e 16 kDa, demonstrada por deglicosilação enzimática. A proteína recombinante foi caracterizada antigenicamente e imunogenicamente por Western blot, utilizando-se anticorpos policlonais equinos anti-EHV-1, e por ELISA indireto em modelo murino, demonstrando que a gD recombinante manteve epítopos similares aos da proteína nativa. Esses resultados sugerem que a gDEHV-1 é um antígeno promissor para uso como imunobiológico no controle do EHV-1.(AU)
Equine herpesvirus 1 (EHV-1) has a worldwide distribution and causes serious damage to horse breeding. It is an agent of respiratory, reproductive and neurological disease outbreaks in young and adult equids. Viral envelope glycoprotein D (gD) is essential for binding and penetration into permissive cells and targeting the host immune system, inducing humoral and cellular immune responses, and is an appropriate antigen for use in vaccines and immunodiagnostics. The objective of this work was to express in Pichia pastoris and to characterize EHV-1 gD for later use as an antigen in immunodiagnostic techniques and formulation of recombinant vaccines. A DNA sequence encoding a truncated form of gDEHV-1 has been cloned into the P. pastoris expression vector pPICZαA. A protein of ~41 kDa was obtained as expected. The protein presented glycosylation between 4 kDa and 16 kDa, demonstrated by enzymatic deglycosylation. The recombinant protein was antigenically and immunogenically characterized by Western blot using equine polyclonal anti-EHV-1 antibodies, and by indirect ELISA in a murine model, demonstrating that the recombinant gD maintained epitopes similar to those of the native protein. These results suggest that gDEHV-1 is a promising antigen for use as an immunobiological in the control of EHV-1.(AU)
Assuntos
Animais , Pichia/isolamento & purificação , Glicoproteínas , Herpesvirus Equídeo 1/isolamento & purificação , Doenças Respiratórias/veterinária , Cavalos/virologiaRESUMO
BACKGROUND: Candida is the leading cause of vaginitis, and 75% of women have at least one episode of infection in their lives, with pregnancy being a predisposing factor. If left untreated, vulvovaginal candidiasis (VVC) can lead to chorioamnionitis with subsequent abortion, prematurity and congenital infection of the neonate. We aimed to determine the prevalence of VVC, identify the recent and most frequently occurring species of Candida in pregnant women, and determine the most effective antifungal drug of choice for treatment. METHOD: A prospective cross-sectional study in which 176 high vaginal swab samples of consented pregnant women visiting the antenatal clinic from February 2018 to April 2018 were subjected to direct gram smear and culture for Candida isolation. Candida isolates were identified using a germ tube test and HiCrome Candida differential agar. Candida isolates were then subjected to a disk diffusion method using fluconazole (25 µg), nystatin (100 units), and voriconazole (1 µg) on Mueller-Hinton agar supplemented with 2% (w/v) glucose and 0.5 µg/ml methylene blue dye to determine the susceptibility pattern as per the guidelines of the Clinical Laboratory Standard Institute (CLSI). Chi-square analysis was used to ascertain the significant association of participants' sociodemographics and clinical presentations to VVC. A univariate logistic regression model was used to identify potential risk factors of VVC. RESULTS: The prevalence of VVC among our study participants was 30.7%. Non-albicans Candida (NAC) and Candida albicans had a prevalence of 74.1 and 25.9%, respectively. Candida glabrata was the most common species, followed by Candida albicans, Candida krusei, and Candida parapsilosis. 50.0, 18.5 and 3.7% of Candida species were susceptible to voriconazole, fluconazole and nystatin, respectively, whereas 37.0, 48.1 and 9.3% of Candida species were resistant to voriconazole, fluconazole and nystatin, respectively. The majority of isolates were susceptible dose dependent to all three antifungal agents, with voriconazole being the most efficacious antifungal agent. There was no significant association between participants' socio-demographic information and clinical presentations to VVC. CONCLUSION: The prevalence of VVC was high in the study area. C. glabrata was found to be the most common cause of VVC among the pregnant women attending antenatal clinics, in the Ho Municipality region of Ghana. The majority of the Candida isolates were susceptible and resistant to voriconazole and fluconazole, respectively.
Assuntos
Candidíase Vulvovaginal/epidemiologia , Complicações na Gravidez/epidemiologia , Adolescente , Adulto , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Candida/classificação , Candida/efeitos dos fármacos , Candida/isolamento & purificação , Candida albicans/efeitos dos fármacos , Candida albicans/isolamento & purificação , Candida glabrata/efeitos dos fármacos , Candida glabrata/isolamento & purificação , Candida parapsilosis/efeitos dos fármacos , Candida parapsilosis/isolamento & purificação , Candidíase Vulvovaginal/tratamento farmacológico , Candidíase Vulvovaginal/microbiologia , Estudos Transversais , Feminino , Fluconazol/farmacologia , Fluconazol/uso terapêutico , Gana/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , Pichia/efeitos dos fármacos , Pichia/isolamento & purificação , Gravidez , Complicações na Gravidez/microbiologia , Gestantes , Prevalência , Estudos Prospectivos , Esfregaço Vaginal , Voriconazol/farmacologia , Voriconazol/uso terapêutico , Adulto JovemRESUMO
In this study, a yeast strain with an outstanding NH3-N degradation ability was isolated from the sediment of a black-odor water channel in Guangdong Province, China. Based on phenotypic and phylogenetic analysis, this strain was identified as Pichia kudriavzevii GW1. The optimum conditions for NH3-N degradation by the GW1 strain were as follows: 0.3% inoculum concentration, 1.5 L/min aeration, pH 7, and a temperature of 35°C. Under optimized conditions, the GW1 strain degraded 95.5% of the NH3-N. The strain was then added to simulated black-odor water under optimal degradation conditions to investigate changes to the bacterial community over time. 16S rRNA sequencing of samples collected on days 0, 7, 14, and 21 showed that, in the presence of the GW1 strain, the relative abundances of the phyla Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes increased in the black-odor water. In addition, the relative abundance of Propionivibrio, a known NH3-N degrading genus, increased. This study will facilitate the use of microbiological methods to repair black-odor water.
Assuntos
Amônia/metabolismo , Pichia , Esgotos/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Análise da Demanda Biológica de Oxigênio , China , Nitrogênio/metabolismo , Odorantes , Pichia/classificação , Pichia/genética , Pichia/isolamento & purificação , Pichia/metabolismo , Esgotos/química , Temperatura , Purificação da ÁguaRESUMO
The consumption of probiotics has increased due to the reported health benefits, mainly in preventing or treating gastrointestinal pathology. This study investigated the antimicrobial capacity of yeasts, Saccharomyces cerevisiae and Pichia kluyveri, previously isolated from fermented foods (indigenous beverage, kefir and cocoa) against the adhesion of foodborne pathogens to Caco-2 cells. Co-aggregation of yeasts with pathogens and were evaluated by quantitative analysis and using scanning electron and laser confocal microscopies. All yeasts strains were able to co-aggregate with the tested pathogens, however, this activity was strain-dependent. The inhibition tests showed that the adhesion of Escherichia coli EPEC, Listeria monocytogenes and Salmonella Enteritidis to Caco-2 was reduced by all the yeasts studied. Most of the evaluated yeasts showed inhibition rates equal to or greater than the commercial probiotic Saccharomyces boulardii. The yeasts were able to reduce up to 50% of the bacterial infection, as observed for CCMA0615 towards EPEC in exclusion assay; CCMA0731, CCMA0732 and CCMA0615 towards L. monocytogenes in exclusion and competition assays; and CCMA0731 in exclusion and CCMA0731, CCMA0732, CCMA0615 in competition assay towards S. Enteritidis. No antimicrobial compounds were produced by the yeasts, showing that competition for nutrients and/or receptors in the intestinal mucosa was the mechanism to bacterial inhibition.
Assuntos
Antibiose , Alimentos Fermentados/microbiologia , Pichia/fisiologia , Saccharomyces cerevisiae/fisiologia , Aderência Bacteriana , Brasil , Células CACO-2 , Escherichia coli/fisiologia , Microbiologia de Alimentos , Humanos , Listeria monocytogenes/fisiologia , Pichia/genética , Pichia/isolamento & purificação , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/isolamento & purificação , Salmonella enteritidis/fisiologiaRESUMO
Five Candida krusei isolates (susceptible and resistant) recovered from the urine of a kidney transplant patient treated with voriconazole (VRC) 200 mg twice daily for 20 days were studied. Eight unrelated clinical isolates of C. krusei were exposed in vitro to VRC 0.001 µg/ml for 30 days. Development of VRC transient resistance occurred in vivo, and induction of permanent resistance occurred in vitro Mostly, ABC1 and ERG11 genes were overexpressed, and a homozygous T418C mutation in the ERG11 gene was found.
Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Antifúngicos/farmacologia , Farmacorresistência Fúngica/genética , Micoses/tratamento farmacológico , Pichia/efeitos dos fármacos , Voriconazol/farmacologia , Transportadores de Cassetes de Ligação de ATP/genética , Sistema Enzimático do Citocromo P-450/genética , Feminino , Humanos , Transplante de Rim/efeitos adversos , Testes de Sensibilidade Microbiana , Micoses/microbiologia , Pichia/genética , Pichia/isolamento & purificação , Adulto JovemRESUMO
BACKGROUND: A sudden rise of Candida krusei candidemia cases was noticed in our hospital within 1 year with maximum cases from paediatric unit. The present study reports the results of epidemiological investigation of possible outbreak of candidemia by C. krusei in paediatric unit at our tertiary care centre. METHODS: Clinical characteristics and risk factors associated with C. krusei candidemia were evaluated. Yeast identification and antifungal susceptibility testing was performed according to standard protocol. To find the potential source of C. krusei in hospital environment and hand colonization, swabs were collected from different fomites (n = 40) and hand washings from 24 health care workers (HCW), respectively. Infection control and prevention practices were intensified following the recognition of outbreak. Genetic typing was done by fluorescent amplified fragment length polymorphism (FAFLP) technique. Case-control comparison was performed with C. tropicalis and C. pelliculosa cases. RESULTS: Candida krusei fungaemia significantly affected paediatric group (82/186, 44%) as compared to adults (14/130, 10.8%; p < 0.001). Among paediatric group, maximum isolation was reported from neonatal unit of paediatric emergency (NUPE). C. krusei was isolated from hands of one HCW and washbasin in NUPE. FAFLP revealed clonality between blood and environmental isolates indicating cross-transmission of C. krusei. Gastrointestinal disease (p = 0.018), previous antibiotics (p = 0.021) especially to carbapenems (p = 0.039), was significant among C. krusei candidemia cases compared to C. pelliculosa cases. CONCLUSION: We report the largest outbreak of C. krusei candidemia in paediatric unit within 1 year with isolation of related strains from environment and hands of HCW. Routine screening of hand hygiene practices revealed non-compliance to standard practices leading to the increase in C. krusei candidemia cases.
Assuntos
Candidemia , Pichia/isolamento & purificação , Adolescente , Adulto , Antifúngicos/uso terapêutico , Candida/efeitos dos fármacos , Candida/isolamento & purificação , Candida/patogenicidade , Candidemia/sangue , Candidemia/tratamento farmacológico , Candidemia/microbiologia , Candidemia/patologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Surtos de Doenças , Feminino , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Pichia/efeitos dos fármacos , Pichia/patogenicidade , Prevalência , Fatores de Risco , Centros de Atenção Terciária , Adulto JovemRESUMO
In situ bioremediation processes are important for control of pollution and clean-up of contaminated sites. The study and implementation of such processes can be designed through investigations on natural mechanisms of absorption, biotransformation, bioaccumulation and toxicity of pollutants in plants and microorganisms. Here, the phytotoxic effects of Cr(VI) and Cd(II) on seed germination and plant growth of Lepidium sativum have been examined at various concentrations (30-300â¯mg/L) in single ion solutions. The studies also addressed the ecotoxicity of metal ions on Azotobacter chroococcum and Pichia sp. isolated from soil. Microbial growth was estimated by weighing the dry biomass and determining the enzymatic activities of dehydrogenase and catalase. The results showed that Cr(VI) and Cd(II) can inhibit L. sativum seed germination and root development, depending on the metal ion and its concentration. The phytotoxic effect of heavy metals was also confirmed by the reduced amounts of dried biomass. Toxicity assays demonstrated the adverse effect of Cr(VI) and Cd(II) on growth of Azotobacter sp. and Pichia sp., manifested by a biomass decrease of more than 50 % at heavy metal concentrations of 150-300â¯mg/L. The results confirmed close links between phytotoxicity of metals and their bioavailability for phytoextraction. Studies on the bioremediation potential of soils contaminated with Cr(VI) and Cd(II) using microbial strains focusing on Azotobacter sp. and Pichia sp. showed that the microbes can only tolerate heavy metal stress at low concentrations. These investigations on plants and microorganisms revealed their ability to withstand metal toxicity and develop tolerance to heavy metals.
Assuntos
Azotobacter/efeitos dos fármacos , Germinação/efeitos dos fármacos , Lepidium sativum/efeitos dos fármacos , Metais Pesados/toxicidade , Pichia/efeitos dos fármacos , Plântula/efeitos dos fármacos , Azotobacter/crescimento & desenvolvimento , Azotobacter/isolamento & purificação , Biodegradação Ambiental , Relação Dose-Resposta a Droga , Lepidium sativum/crescimento & desenvolvimento , Pichia/crescimento & desenvolvimento , Pichia/isolamento & purificação , Microbiologia do SoloRESUMO
BACKGROUND: Komagataella phaffii is a yeast widely used in the pharmaceutical and biotechnology industries, and is one of the two species that were previously called Pichia pastoris. However, almost all laboratory work on K. phaffii has utilized strains derived from a single natural isolate, CBS7435. There is little information about the sequence diversity of K. phaffii or the genetic properties of this species. RESULTS: We sequenced the genomes of all the known isolates of K. phaffii. We made a genetic cross between derivatives of two isolates that differ at 44,000 single nucleotide polymorphism sites, and used this cross to analyze the rate and landscape of meiotic recombination. We conducted tetrad analysis by making use of the property that K. phaffii haploids do not mate in rich media, which enabled us to isolate and sequence the four types of haploid cell that are present in the colony that forms when a tetra-type ascus germinates. CONCLUSIONS: We found that only four distinct natural isolates of K. phaffii exist in public yeast culture collections. The meiotic recombination rate in K. phaffii is approximately 3.5 times lower than in Saccharomyces cerevisiae, with an average of 25 crossovers per meiosis. Recombination is suppressed, and genetic diversity among natural isolates is low, in a region around centromeres that is much larger than the centromeres themselves. Our work lays a foundation for future quantitative trait locus analysis in K. phaffii.
Assuntos
Genômica , Meiose/genética , Pichia/genética , Recombinação Genética/genética , Pichia/isolamento & purificação , Saccharomyces cerevisiae/genéticaRESUMO
Ishizuchi-kurocha is a Japanese traditional fermented tea that is produced by primary aerobic and secondary fermentation steps. The secondary fermentation step of Ishizuchi-kurocha is mainly mediated through lactic acid bacteria. Here, we performed quantitative analyses of the culturable fungal communities at each step and identified several morphologically representative fungal isolates. While filamentous fungi (median, 3.2â¯×â¯107â¯CFU/g sample) and yeasts (median, 3.7â¯×â¯107â¯CFU/g) were both detected after the primary fermentation step, only yeasts (median, 1.6â¯×â¯107â¯CFU/g) were detected in the end of the secondary fermentation step, suggesting that the fungal community in tea leaves are dramatically changed between the two steps. Pichia kudriavzevii and Pichia manshurica, the prevalent fungal species at the end of the secondary fermentation step, grew well in exudate from the secondary fermentation step. P. kudriavzevii also grew well in media containing d- or l-lactate as the sole carbon source. The growth of the disruptant of cyb2A encoding a cytochrome b2 lactate dehydrogenase in P. kudriavzevii was severely impaired on medium supplemented with l-lactate, but not d-lactate, suggesting that Cyb2Ap plays a crucial role in the use of l-lactate, and P. kudriavzevii efficiently uses both l- and d-lactate as carbon sources. Thus, lactate assimilation seems to be a key phenotype to become a prevalent species in the secondary fermentation step, and Cyb2Ap has a pivotal role in l-lactate metabolism in P. kudriavzevii. Further understanding and engineering of P. kudriavzevii and P. manshurica will contribute to the control of lactic acid bacteria fermentation during the fermented tea production and also to other industrial uses.
Assuntos
Alimentos Fermentados/microbiologia , L-Lactato Desidrogenase (Citocromo)/genética , Ácido Láctico/metabolismo , Pichia/genética , Pichia/metabolismo , Reatores Biológicos , Candida/isolamento & purificação , Fermentação , Pichia/isolamento & purificação , Leveduras/isolamento & purificaçãoRESUMO
A 23-year-old female, who had undergone a sleeve gastrectomy two weeks earlier, presented with abdominal complaints. A CT scan showed portal vein thrombosis, bowel ischemia, and intra-abdominal sepsis. Anastomosis and antibiotic therapy were not successful, and the patient went into multi-organ failure and died. Multiple cultures revealed a yeast fungus confirmed as Pichia kudriavzevii using rRNA gene sequencing. We report the first case of peritonitis in association with P kudriavzevii. In addition to the abdominal complications and surgical interventions, the yeast was found to have significantly contributed to the patient's death. SIMILAR CASES PUBLISHED: None. CONFLICT OF INTEREST: None.
Assuntos
Gastrectomia/efeitos adversos , Micoses/diagnóstico , Peritonite/diagnóstico , Pichia/isolamento & purificação , Evolução Fatal , Feminino , Gastrectomia/métodos , Humanos , Insuficiência de Múltiplos Órgãos/microbiologia , Micoses/microbiologia , Peritonite/microbiologia , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
Kodamaea ohmeri keratitis is an opportunistic pathogen seen in patients who have undergone invasive procedures and immunocompromised state. It has been identified in septicemia patients, resulting in mortality. To the best of our knowledge, we identified the first case of K. ohmeri keratitis following an injury with vegetative material. A 57-year-old woman with underlying, poorly controlled diabetes mellitus was gardening when a tree leaf accidentally poked her in the eye. Two weeks later, the patient presented with right eye pain, redness and progressive blurring of vision due to a traumatised right cornea. Slit-lamp examination showed a small inferior paracentral corneal stromal infiltrate with overlying epithelial defect. A corneal scraping sample yielded K. ohmeri from Analytical Profile Index (API) 20C yeast identification system. She was treated with intensive topical amphotericin B and fluconazole. After 6 weeks of treatment, the keratitis resolved with faint scar tissue, and her visual acuity improved.
Assuntos
Córnea/microbiologia , Infecções Oculares Fúngicas/tratamento farmacológico , Ceratite/microbiologia , Administração Tópica , Anfotericina B/administração & dosagem , Anfotericina B/uso terapêutico , Antifúngicos/administração & dosagem , Antifúngicos/uso terapêutico , Córnea/patologia , Lesões da Córnea/complicações , Substância Própria/patologia , Feminino , Fluconazol/administração & dosagem , Fluconazol/uso terapêutico , Humanos , Hospedeiro Imunocomprometido , Ceratite/patologia , Pessoa de Meia-Idade , Pichia/isolamento & purificação , Folhas de Planta/efeitos adversos , Folhas de Planta/microbiologia , Resultado do Tratamento , Acuidade Visual/efeitos dos fármacosRESUMO
Fermented cereal doughs constitute a predominant part of West African diets. The environment of fermented doughs can be hostile for microbial survival due to high levels of microbial metabolites such as weak carboxylic organic acids and ethanol. In order to get a better understanding of the intrinsic factors affecting the microbial successions of yeasts during dough fermentation, survival and physiological responses of the yeasts associated with West African fermented cereal doughs were investigated at exposure to relevant concentrations of microbial inhibitory compounds. Three strains each of the predominant species, i.e. Saccharomyces cerevisiae, Kluyveromyces marxianus, Pichia kudriavzevii as well as the opportunistic pathogen Candida glabrata were studied. The strains were exposed to individual stress factors of cereal doughs, i.e. (i) pHâ¯3.4, (ii) 3% (v/v) ethanol (EtOHpH3.4), (iii) 285â¯mM lactic acid (LApH3.4) and (iv) 150â¯mM acetic acid (AApH3.4) as well as to combinations of these stress factors, i.e. (v) (LAâ¯+â¯AA)pHâ¯3.4 and (vi) (LAâ¯+â¯AA+EtOH)pHâ¯3.4. Growth and single cell viability were studied by flow cytometry using combined SYTO 13 and propidium iodide (PI) staining. Intracellular pH (pHi), plasma membrane integrity and micro-colony development of stressed cells were studied by fluorescence microscopy using PI and carboxyfluorescein diacetate succinimidyl ester (CFDA-se). Viability of the yeast strains was not affected by pHâ¯3.4 and 3% (v/v) ethanol (EtOHpH3.4). 285â¯mM lactic acid (LApH3.4) reduced the specific growth rate (µmax) from 0.27-0.41â¯h-1 to 0.11-0.26â¯h-1 and the viability from 100% to 2.6-41.7% at 72â¯h of exposure in most yeast strains, except for two strains of C. glabrata. 150â¯mM acetic acid (AApH3.4) as well as the combinations (LAâ¯+â¯AA)pHâ¯3.4 and (LAâ¯+â¯AA+EtOH)pHâ¯3.4 reduced µmax to 0.0â¯h-1 and induced significant cell death for all the yeast strains. Exposed to (LAâ¯+â¯AA+EtOH)pHâ¯3.4, the most resistant yeast strains belonged to S. cerevisiae followed by P. kudriavzevii, whereas C. glabrata and K. marxianus were more sensitive. Strain variations were observed within all four species. When transferred to non-stress conditions, i.e. MYGP, pHâ¯5.6, after exposure to (LAâ¯+â¯AA+EtOH)pHâ¯3.4 for 6â¯h, 45% of the single cells of the most resistant S. cerevisiae strain kept their plasma membrane integrity, recovered their pHi to near physiological range (pHiâ¯=â¯6.1-7.4) and resumed proliferation after 3-24â¯h of lag phase. The results obtained are valuable in order to change processing conditions of the dough to favor the survival of preferable yeast species, i.e. S. cerevisiae and K. marxianus and inhibit opportunistic pathogen yeast species as C. glabrata.