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
Previous investigations proved the potential of Saccharomyces cerevisiae MBELGA62 and Pichia kudriavzevii MBELGA61 as suitable biocontrolling agents against Aspergillus sp. through the production of soluble and volatile bioactive antifungal compounds. The present study delves into those finding by means of the identification of the volatile compounds produced by brewer's strains that demonstrated fungistatic and fungicidal effects against Aspergillus flavus and A. parasiticus when cultured in brewer's wort agar plates. Traditional brewer's yeasts such as S. cerevisiae MBELGA62 and Saccharomyces pastorianus SAFS235 synthetize volatiles that fully inhibited mycelial development for up to 9 days at 30 °C. The non-conventional brewer's strains P. kudriavzevii MBELGA61 and Meyerozyma guilliermondii MUS122 increased the lag phase by >100% and significantly reduced the fungal growth rate by 27.5-43.0% and 15.4-31.4%, respectively. In this context, 2-phenylethanol, 2-phenylethyl acetate and benzyl alcohol were identified as the main antifungal agents involved in Aspergillus sp.'s inhibition.
Assuntos
Antifúngicos , Aspergillus , Fermentação , Saccharomyces cerevisiae , Compostos Orgânicos Voláteis , Aspergillus/efeitos dos fármacos , Aspergillus/metabolismo , Aspergillus/crescimento & desenvolvimento , Antifúngicos/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Pichia/metabolismo , Pichia/efeitos dos fármacos , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/farmacologia , Álcool Feniletílico/metabolismoRESUMO
The search for coatings that extend the useful life of biomedical devices has been of great interest, and titanium has been of great relevance due to its innocuousness and low reactivity. This study contributes to the investigation of Ti/Ag films in different configurations (monolayer and multilayer) deposited by magnetron sputtering. The sessile droplet technique was applied to study wettability; greater film penetrability was obtained when Ag is the external layer, conferring high efficiency in cell adhesion. The morphological properties were characterized by SEM, which showed porous nuclei on the surface in the Ag coating and crystals embedded in the Ti film. The structural properties were studied by XRD, revealing the presence of TiO2 in the anatase crystalline phase in a proportion of 49.9% and the formation of a silver cubic network centered on the faces. Tafel polarization curves demonstrated improvements in the corrosion current densities of Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti and Ti/Ag compared to the Ag coating, with values of 0.1749, 0.4802, and 2.044 nA.m-2, respectively. Antimicrobial activity was evaluated against the bacteria Pseudomonas aeruginosa and Bacillus subtilis and the yeasts Candida krusei and Candida albicans, revealing that the Ti/Ag and Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti coatings exhibit promise in biomedical material applications.
Assuntos
Materiais Revestidos Biocompatíveis/química , Prata/farmacologia , Titânio/farmacologia , Molhabilidade/efeitos dos fármacos , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/patogenicidade , Candida/efeitos dos fármacos , Candida/patogenicidade , Materiais Revestidos Biocompatíveis/farmacologia , Humanos , Teste de Materiais , Pichia/efeitos dos fármacos , Pichia/patogenicidade , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Prata/química , Propriedades de Superfície , Titânio/químicaRESUMO
The assertion made by Wu et al. that aromaticity may have considerable implications for molecular design motivated us to use nucleus-independent chemical shifts (NICS) as an aromaticity criterion to evaluate the antifungal activity of two series of indol-4-ones. A linear regression analysis of NICS and antifungal activity showed that both tested variables were significantly related (p < 0.05); when aromaticity increased, the antifungal activity decreased for series I and increased for series II. To verify the validity of the obtained equations, a new set of 44 benzofuran-4-ones was designed by replacing the nitrogen atom of the five-membered ring with oxygen in indol-4-ones. The NICS(0) and NICS(1) of benzofuran-4-ones were calculated and used to predict their biological activities using the previous equations. A set of 10 benzofuran-4-ones was synthesized and tested in eight human pathogenic fungi, showing the validity of the equations. The minimum inhibitory concentration (MIC) in yeasts was 31.25 µg·mL-1 for Candida glabrata, Candida krusei and Candida guilliermondii with compounds 15-32, 15-15 and 15-1. The MIC for filamentous fungi was 1.95 µg·mL-1 for Aspergillus niger for compounds 15-1, 15-33 and 15-34. The results obtained support the use of NICS in the molecular design of compounds with antifungal activity.
Assuntos
Antifúngicos/farmacologia , Benzofuranos/farmacologia , Fungos/efeitos dos fármacos , Antifúngicos/química , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/patogenicidade , Benzofuranos/química , Candida/efeitos dos fármacos , Candida/patogenicidade , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pichia/efeitos dos fármacos , Pichia/patogenicidade , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/farmacologiaRESUMO
This study aimed to investigate the chemical composition and antifungal potential of the essential oil of Baccharis trimera (Less.) DC. against Candida strains. The half maximal inhibitory concentration (IC50) was assessed by the microdilution method using the essential oil at a concentration range of 8192 to 8 µg/mL. The minimum fungicide concentration (MFC) was determined by subculture in solid medium. The ability of the essential oil to modulate the activity of antifungals was determined in wells treated simultaneously with the oil at a subinhibitory concentration (MFC/16) and fluconazole (FCZ). The fungal morphology was analyzed by microscopy. Gas chromatography coupled with mass spectrometry (GC/MS) was used to identify the chemical composition. The essential oil presented an CI50 of 11.24 and 1.45 µg/mL, which was found to potentiate the effect of FCZ against Candida albicans. On the other hand, this combined treatment resulted in antagonism against Candida tropicalis and no evident modulation against Candida krusei was observed. The essential oil significantly inhibited hyphae growth. However, with a MFC ≥ 16,384 µg/mL, it is assumed that it has a fungistatic action. The antifungal properties demonstrated in this study might be related to the presence of sesquiterpenes and monoterpenes, and the interaction between them. In conclusion, Baccharis trimera showed promising anti-Candida effects, in addition to potentiating the activity of FCZ against Candida albicans, affecting its morphological transition. Therefore, this species constitutes a source of chemical compounds with the potential to be used in the combat of fungal infections.
Assuntos
Baccharis , Candida , Óleos Voláteis , Antifúngicos/farmacologia , Baccharis/química , Candida/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologia , Compostos Fitoquímicos/farmacologia , Pichia/efeitos dos fármacosRESUMO
Posaconazole exhibits in-vitro activity against Candida glabrata and Candida krusei. Epidemiological cut-off values set by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI) are 1/1 and 0.5/0.5 mg/L, respectively, but clinical breakpoints have not been established to date. This study explored the pharmacodynamics (PD) of posaconazole in a validated one-compartment in-vitro pharmacokinetic (PK)/PD model, and determined the probability of PK/PD target attainment (PTA) for the available formulations. Five C. glabrata and three C. krusei isolates with posaconazole minimum inhibitory concentrations (MICs) of 0.06-2 and 0.03-0.25 mg/L, respectively, were tested in the PK/PD model simulating different time-concentration profiles of posaconazole. The exposure-effect relationship fAUC0-24/MIC was described for EUCAST/CLSI methods, and PTA was calculated in order to determine PK/PD susceptibility breakpoints for oral solution (400 mg q12h), and intravenous (i.v.)/tablet formulations (300 mg q24h). Fungicidal activity (~2log kill) was found against the most susceptible C. glabrata isolate alone, and against all three C. krusei isolates. The corresponding EUCAST/CLSI PK/PD targets (fAUC0-24/MIC) were 102/79 for C. glabrata and 12/8 for C. krusei. Mean PTA was high (>95%) for C. glabrata isolates with EUCAST/CLSI MICs ≤0.03/≤0.03 mg/L for oral solution and ≤0.125/≤0.125 mg/L for i.v. and tablet formulations for the wild-type population. For C. krusei isolates, mean PTA was high (>95%) for EUCAST/CLSI MICs ≤0.25/≤0.5 mg/L for oral solution and ≤1/≤2 mg/L for i.v. and tablet formulations for the wild-type population. The use of posaconazole to treat C. glabrata infections is questionable. Intravenous and tablet formulations may be therapeutic options for the treatment of C. krusei infections, and oral exposure can be optimized with therapeutic drug monitoring (trough levels >0.6-0.9 mg/L).
Assuntos
Candida glabrata/efeitos dos fármacos , Composição de Medicamentos/métodos , Pichia/efeitos dos fármacos , Triazóis/farmacocinética , Triazóis/uso terapêutico , Antifúngicos/farmacocinética , Antifúngicos/uso terapêutico , Monitoramento de Medicamentos , Testes de Sensibilidade Microbiana , Método de Monte CarloRESUMO
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
ETHNOPHARMACOLOGICAL RELEVANCE: The dicotyledonous plant Piptadeniastrum africanum (hook.f.) Brennan (Fabaceae) is used in traditional medicine to treat various human complaints including bronchitis, coughing, urino-genital ailments, meningitis, abdominal pain, treatment of wounds, malaria and gastrointestinal ailments, and is used as a purgative and worm expeller. AIM OF THE STUDY: The present study describes the phytochemical investigation and the determination of the antimicrobial, antiplasmodial and antitrypanosomal activities of crude extract, fractions and compounds extracted from Piptadeniastrum africanum roots. MATERIALS AND METHODS: Isolated compounds were obtained using several chromatographic techniques. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR) and by comparing their NMR data with those found in literature. In vitro antimicrobial activity of samples was evaluated using the microdilution method on bacterial (Escherichia coli, Proteus mirabilis, Staphylococcus aureus) and fungal (Candida krusei) strains, while in vitro cell-growth inhibition activities were assessed against two parasites (Trypanosoma brucei brucei and Plasmodium falciparum strain 3D7). The cytotoxicity properties of samples were assayed against HeLa human cervical carcinoma. RESULTS: Five compounds were isolated and identified as: tricosanol 1, 5α-stigmasta-7,22-dien-3-ß-ol 2, betulinic acid 3, oleanolic acid 4 and piptadenamide 5. This is the first report of the isolation of these five compounds from the roots of P. africanum. The (Hex:EtOAc 50:50) fraction exhibited moderate antibacterial activity against P. mirabilis (MIC 250⯵g/mL), while the other fractions and isolated compounds had weak antimicrobial activities. Only the EtOAc fraction presented a moderate antimalarial activity with an IC50 of 16.5⯵g/mL. The MeOH crude extract and three fractions (Hexane, Hexane-EtOAc 25% and EtOAc-MeOH 25%) exhibited significant trypanocidal activity with IC50 values of 3.0, 37.5, 3.8 and 9.5⯵g/mL, respectively. CONCLUSION: These results demonstrated a scientific rational of the traditional uses of P. africanum and indicate that this plant should be further investigated to identify some of the chemical components that exhibited the activities reported in this study and therefore may constitute new lead candidates in parasiticidal drug discovery.
Assuntos
Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Fabaceae/química , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Raízes de Plantas/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Anti-Infecciosos/toxicidade , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Antimaláricos/isolamento & purificação , Antimaláricos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Células HeLa , Humanos , Compostos Fitoquímicos/toxicidade , Pichia/efeitos dos fármacos , Pichia/crescimento & desenvolvimento , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/crescimento & desenvolvimento , Tripanossomicidas/isolamento & purificação , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/crescimento & desenvolvimentoRESUMO
2-Phenylethanol (2-PE) is an important flavor compound but also impairs cell growth severely, which in turn blocks its bioproduction. However, the molecular mechanism of 2-PE tolerance is unclear. In this study, a superb 2-PE stress-tolerant and producing yeast, Candida glycerinogenes, was selected to uncover the underlying mechanism of 2-PE tolerance. We discovered that Hap5 is an essential regulator to 2-PE resistance, and its induction by 2-PE stress occurs at the post-transcriptional level, rather than at the transcriptional level. Under 2-PE stress, Hap5 is activated and imported into the nucleus rapidly. Then, the nuclear Hap5 binds to the glutathione synthetase (gsh2) promoter via CCAAT box, to induce the expression of gsh2 gene. The increased gsh2 expression contributes to enhanced cellular glutathione content, and consequently alleviates ROS accumulation, lipid peroxidation, and cell membrane damage caused by 2-PE toxicity. Specifically, increasing the expression of gsh2 is effective in improving not just 2-PE tolerance (33.7% higher biomass under 29 mM 2-PE), but also 2-PE production (16.2% higher). This study extends our knowledge of 2-PE tolerance mechanism and also provides a promising strategy to improve 2-PE production.
Assuntos
Proteínas Fúngicas/genética , Glutationa Sintase/genética , Álcool Feniletílico/farmacologia , Pichia/efeitos dos fármacos , Fatores de Transcrição/genética , Membrana Celular/efeitos dos fármacos , Regulação Fúngica da Expressão Gênica , Glutationa/metabolismo , Peroxidação de Lipídeos , Pichia/genética , Pichia/metabolismo , Regiões Promotoras Genéticas , Espécies Reativas de Oxigênio/metabolismoRESUMO
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
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: 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
The methylotrophic yeast Pichia pastoris is widely used in the manufacture of industrial enzymes and pharmaceuticals. Like most biotechnological production hosts, P. pastoris is heterotrophic and grows on organic feedstocks that have competing uses in the production of food and animal feed. In a step toward more sustainable industrial processes, we describe the conversion of P. pastoris into an autotroph that grows on CO2. By addition of eight heterologous genes and deletion of three native genes, we engineer the peroxisomal methanol-assimilation pathway of P. pastoris into a CO2-fixation pathway resembling the Calvin-Benson-Bassham cycle, the predominant natural CO2-fixation pathway. The resulting strain can grow continuously with CO2 as a sole carbon source at a µmax of 0.008 h-1. The specific growth rate was further improved to 0.018 h-1 by adaptive laboratory evolution. This engineered P. pastoris strain may promote sustainability by sequestering the greenhouse gas CO2, and by avoiding consumption of an organic feedstock with alternative uses in food production.
Assuntos
Processos Autotróficos/fisiologia , Dióxido de Carbono/farmacologia , Processos Heterotróficos/fisiologia , Pichia/crescimento & desenvolvimento , Processos Autotróficos/efeitos dos fármacos , Reatores Biológicos , Isótopos de Carbono , Processos Heterotróficos/efeitos dos fármacos , Engenharia Metabólica , Peroxissomos/efeitos dos fármacos , Peroxissomos/metabolismo , Fotossíntese/efeitos dos fármacos , Pichia/efeitos dos fármacos , Ribulose-Bifosfato Carboxilase/metabolismo , Xilulose/metabolismoRESUMO
BACKGROUND: Voriconazole exhibits in vitro activity against Candida glabrata and Candida krusei (EUCAST/CLSI epidemiological cut-off values 1/0.25 and 1/0.5 mg/L, respectively). Yet, EUCAST found insufficient evidence to set breakpoints for these species. We explored voriconazole pharmacodynamics (PD) in an in vitro dynamic model simulating human pharmacokinetics (PK). METHODS: Four C. glabrata and three C. krusei isolates (voriconazole EUCAST and CLSI MICs of 0.03-2 mg/L) were tested in the PK/PD model simulating voriconazole exposures (t½ â¼6 h q12h dosing for 3 days). PK/PD breakpoints were determined calculating the PTA for exposure indices fAUC0-24/MIC associated with half-maximal activity (EI50) using Monte Carlo simulation analysis. RESULTS: Fungal load increased from 3.60±0.35 to 8.41±0.24 log10 cfu/mL in the drug-free control, with a maximum effect of â¼1 log10 kill of C. glabrata and C. krusei isolates with MICs of 0.06 and 0.25 mg/L, respectively, at high drug exposures. The 72 h log10 cfu/mL change versus fAUC0-24/MIC relationship followed a sigmoid curve for C. glabrata (R2=0.85-0.87) and C. krusei (R2=0.56-0.76) with EI50 of 49 (32-76) and 52 (33-78) fAUC/MIC for EUCAST and 55 (31-96) and 80 (42-152) fAUC/MIC for CLSI, respectively. The PTAs for C. glabrata and C. krusei isolates with EUCAST/CLSI MICs ≤0.125/≤0.06 mg/L were >95%. Isolates with EUCAST/CLSI MICs of 0.25-1/0.125-0.5 would require trough levels 1-4 mg/L; isolates with higher MICs would not attain the corresponding PK/PD targets without reaching toxicity. CONCLUSIONS: The in vitro PK/PD breakpoints for C. glabrata and C. krusei for EUCAST (0.125 mg/L) and CLSI (0.06 mg/L) bisected the WT populations. Trough levels of >4 mg/L, which are not clinically feasible, are necessary for efficacy against WT isolates.
Assuntos
Antifúngicos/farmacocinética , Candida glabrata/efeitos dos fármacos , Pichia/efeitos dos fármacos , Voriconazol/farmacocinética , Antifúngicos/farmacologia , Farmacorresistência Fúngica , Testes de Sensibilidade Microbiana , Modelos Biológicos , Método de Monte Carlo , Voriconazol/farmacologiaRESUMO
Updated information on the epidemiology of candidemia, particularly during severe socioeconomic events, is important for proper management of these infections. A systematic literature review on candidemia in Greece and a retrospective surveillance study were conducted in a tertiary university hospital during the years of the recent financial crisis (2009 to 2018) in order to assess changes in incidence rates, patient characteristics, species distribution, antifungal susceptibilities, and drug consumption. The average annual incidence of 429 candidemic episodes was 2.03/10,000 bed days, with 9.88 in adult intensive care units (ICUs), 1.74 in surgical wards, and 1.81 in internal medicine wards, where a significant increase was observed (1.15, 1.85, and 2.23/10,000 bed days in 2009 to 2011, 2012 to 2014, and 2015 to 2018, respectively; P = 0.004). Candida albicans was the most common species (41%), followed by Candida parapsilosis species complex [SC] (37%), Candida glabrata SC (11%), Candida tropicalis (7%), Candida krusei (1%), and other rare Candida spp. (3%). Mixed infections were found in 20/429 (4.7%) cases, while 33 (7%) cases were due to non-Candida spp. Overall, 44/311 (14%) isolates were resistant/non-wild type (WT) to the nine antifungals tested, with 23/113 (20%) C. parapsilosis SC and 2/34 (6%) C. glabrata SC isolates being resistant to fluconazole (1 panechinocandin and 2 panazole resistant). All isolates were susceptible/WT to amphotericin B and flucytosine. While the overall consumption of antifungals diminished (P = 0.02), with a mean of 17.93 defined daily doses (DDD)/100 bed days, increased micafungin use was correlated with the rise in C. parapsilosis SC (P = 0.04). A significant increase of candidemia in internal medicine wards and of C. parapsilosis SC infections was found during the years of financial crisis. Although resistance rates remain low (<14%), fluconazole-resistant C. parapsilosis SC and multidrug-resistant C. glabrata SC isolates are of major concern.
Assuntos
Antifúngicos/uso terapêutico , Candidemia/tratamento farmacológico , Candidemia/epidemiologia , Sepse/tratamento farmacológico , Sepse/epidemiologia , Candida glabrata/efeitos dos fármacos , Candida glabrata/patogenicidade , Candida tropicalis/efeitos dos fármacos , Candida tropicalis/patogenicidade , Candidemia/microbiologia , Farmacorresistência Fúngica/genética , Fluconazol/uso terapêutico , Grécia , Humanos , Pichia/efeitos dos fármacos , Pichia/patogenicidade , Sepse/microbiologia , Atenção Terciária à SaúdeRESUMO
Removal of heavy metals from food material by growing micro-organisms is limited by the toxicity to cells. In this study, different preincubation treatments were investigated to analyze their effects on cadmium resistance and removal ability of Pichia kudriavzevii A16 and Saccharomyces cerevisiae CICC1211. Sucrose preincubation improved the cadmium resistance of both yeast cells and increased the cadmium-removal rate of P. kudriavzevii A16. An evident decrease of intracellular and cell-surface cadmium accumulation was observed after sucrose preincubation, which may be the primary reason responsible for the improved cadmium resistance. Flow cytometry assay showed that sucrose significantly reduced the production of reactive oxygen species (ROS) and cell death rate of both yeasts under cadmium compared with those normally cultured cells. Under cadmium stress, the content of both protein carbonyls and malonyldialdehyde were also reduced by the addition of sucrose, the results were in accordance with the tendency of ROS, exhibiting a defending function of sucrose. Osmotic regulators as proline and trehalose were increased by sucrose preincubation in P. kudriavzevii A16 in the presence of cadmium. The results suggested that sucrose preincubation could be applied to improve cadmium resistance and removal rate of yeasts.
Assuntos
Cádmio/metabolismo , Pichia/efeitos dos fármacos , Pichia/metabolismo , Sacarose/farmacologia , Biodegradação Ambiental/efeitos dos fármacos , Cádmio/toxicidade , Viabilidade Microbiana/efeitos dos fármacos , Pichia/fisiologia , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Estresse Fisiológico/efeitos dos fármacos , Trealose/metabolismoRESUMO
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.
Assuntos
Candida/efeitos dos fármacos , Grão Comestível/microbiologia , Alimentos Fermentados/microbiologia , Kluyveromyces/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Pichia/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Ácido Acético/farmacologia , Reatores Biológicos , Candida/crescimento & desenvolvimento , Candida/isolamento & purificação , Etanol/farmacologia , Fermentação , Kluyveromyces/crescimento & desenvolvimento , Kluyveromyces/isolamento & purificação , Ácido Láctico/farmacologia , Pichia/crescimento & desenvolvimento , Pichia/isolamento & purificação , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/isolamento & purificação , Fermento Seco , Leveduras/isolamento & purificaçãoRESUMO
Pichia pastoris KM71H (MutS ) is an efficient producer of hard-to-express proteins such as the membrane protein P-glycoprotein (Pgp), an ATP-powered efflux pump which is expressed properly, but at very low concentration, using the conventional induction strategy. Evaluation of different induction strategies indicated that it was possible to increase Pgp expression by inducing the culture with 20% media containing 2.5% methanol. By quantifying methanol, formaldehyde, hydrogen peroxide and formate, and by measuring alcohol oxidase, catalase, formaldehyde dehydrogenase, formate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenases, it was possible to correlate Pgp expression to the induction strategy. Inducing the culture by adding methanol with fresh media was associated with decreases in formaldehyde and hydrogen peroxide, and increases in formaldehyde dehydrogenase, formate dehydrogenase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenases. At these conditions, Pgp expression was 1400-fold higher, an indication that Pgp expression is affected by increases in formaldehyde and hydrogen peroxide. It is possible that Pgp is responsible for this behaviour, since the increased metabolite concentrations and decreased enzymatic activities were not observed when parental Pichia was subjected to the same growth conditions. This report adds information on methanol metabolism during expression of Pgp from P. pastoris MutS strain and suggests an expression procedure for hard-to-express proteins from P. pastoris.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/biossíntese , Expressão Gênica , Metanol/metabolismo , Pichia/enzimologia , Pichia/metabolismo , Ativação Transcricional/efeitos dos fármacos , Meios de Cultura/química , Perfilação da Expressão Gênica , Pichia/efeitos dos fármacosRESUMO
Cancer chemotherapy possesses high toxicity, particularly when a higher concentration of drugs is administered to patients. Therefore, searching for more effective compounds to reduce the toxicity of treatments, while still producing similar effects as current chemotherapy regimens, is required. Currently, the search for potential anticancer agents involves a random, inaccurate process with strategic deficits and a lack of specific targets. For this reason, the initial in vitro highthroughput steps in the screening process should be reviewed for rapid identification of the compounds that may serve as anticancer agents. The present study aimed to investigate the potential use of the Pichia pastoris strain SMD1168H expressing DNA topoisomerase I (SMD1168HTOPOI) in a yeastbased assay for screening potential anticancer agents. The cell density that indicated the growth of the recombinant yeast without treatment was first measured by spectrophotometry. Subsequently, the effects of glutamate (agonist) and camptothecin (antagonist) on the recombinant yeast cell density were investigated using the same approach, and finally, the effect of camptothecin on various cell lines was determined and compared with its effect on recombinant yeast. The current study demonstrated that growth was enhanced in SMD1168HTOPOI as compared with that in SMD1168H. Glutamate also enhanced the growth of the SMD1168H; however, the growth effect was not enhanced in SMD1168HTOPOI treated with glutamate. By contrast, camptothecin caused only lower cell density and growth throughout the treatment of SMD1168HTOPOI. The findings of the current study indicated that SMD1168HTOPOI has similar characteristics to MDAMB231 cells; therefore, it can be used in a yeastbased assay to screen for more effective compounds that may inhibit the growth of highly metastatic breast cancer cells.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , DNA Topoisomerases Tipo I/metabolismo , Pichia/efeitos dos fármacos , Camptotecina/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , DNA Topoisomerases Tipo I/genética , Ácido Glutâmico/farmacologia , Humanos , Pichia/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genéticaRESUMO
This study evaluated the efficacy of the essential oil from Mentha piperita L. (MPEO) to inactivate cells of the potentially spoilage yeasts Candida albicans, Candida tropicalis, Pichia anomala and Saccharomyces cerevisiae in cashew, guava, mango and pineapple juices during 72â¯h of refrigerated storage. Damage in different physiological functions caused by MPEO in S. cerevisiae in cashew and guava juices were investigated using flow cytometry (FC). The effects of the incorporation of an effective anti-yeast MPEO dose on sensory characteristics of juices were also evaluated. MPEO displayed minimum inhibitory concentration of 1.875⯵L/mL against all tested yeasts. A >5 log reduction in counts of C. albicans, P. anomala and S. cerevisiae was observed in cashew and guava juices with 7.5 and 3.75⯵L/mL MPEO. Tested MPEO concentrations (1.875, 3.75 and 7.5⯵L/mL) were not effective to cause >5 log reduction in counts of target yeasts in mango and pineapple juices during 72â¯h of exposure. Incorporation of 1.875⯵L/mL MPEO in cashew and guava juices strongly compromised membrane permeability, membrane potential, enzymatic activity and efflux pump activity in S. cerevisiae cells. This same MPEO concentration did not affect appearance, odor and viscosity in fruit juices, but negatively affected their taste and aftertaste. These results show the efficacy of MPEO to inactivate potentially spoilage yeasts in fruit juices through disturbance of different physiological functions in yeast cells. However, the combined use of MPEO with other technologies should be necessary to decrease its effective anti-yeast dose in fruit juices and, consequently, the possible negative impacts on specific sensory properties of these products.