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1.
J Clin Microbiol ; 59(10): e0054421, 2021 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-34346718

RESUMO

The FASTinov flow cytometry kit, an ultrarapid antimicrobial susceptibility test, was directly evaluated on positive blood cultures (BC) at two sites: (i) FASTinov, S.A., in Porto, Portugal, using BC spiked with well-characterized bacteria, and (ii) Ramón y Cajal University Hospital in Madrid, Spain, using positive BC from patients. Two kits were evaluated, FASTgramneg (Enterobacterales, Pseudomonas, Acinetobacter) and FASTgrampos (Staphylococcus, Enterococcus). Dedicated software for cytometric data analysis and interpretative reporting, including both CLSI and EUCAST criteria, was used. The FASTgramneg kit also provides information about the presence of resistant mechanisms, including extended-spectrum beta-lactamases (ESBLs) and carbapenemases. After 1 h of incubation at 37°C, bacteria were analyzed using a CytoFLEX cytometer (Beckman, CA). Disk diffusion was performed as the reference susceptibility method. Overall, 447 positive BC were included, 100 from hospitalized patients. Categorical agreement values for the FASTgramneg panel were 96.8% based on EUCAST criteria and 96.4% based on CLSI criteria. For the FASTgrampos panel, categorical agreement was 98.6% when using both criteria. When EUCAST criteria were used, the percentages of errors for the FASTgramneg panel were 2.1% minor errors (mE), 1.3% major errors (ME), and 0.6% very major errors (VME). When CLSI criteria were used, 2.9% mE, 0.9% ME, and 0.4% VME were found. VME were mainly observed with amoxicillin-clavulanate, cefotaxime, ceftazidime, and gentamicin. The FASTgrampos panel showed 0.3% mE, 1.4% ME, and 0.4% VME when EUCAST criteria were used (VME with respect to gentamicin and Staphylococcus) and 0.4% mE, 1.4% ME, and no VME when CLSI criteria were used. The FASTinov flow cytometry kits represent a rapid alternative for direct antimicrobial susceptibility testing from positive BC, showing time to results of <2 h, and can be used to personalize antibiotic and stewardship practices.


Assuntos
Antibacterianos , Hemocultura , Antibacterianos/farmacologia , Bactérias , Citometria de Fluxo , Humanos , Testes de Sensibilidade Microbiana
2.
Eur J Clin Microbiol Infect Dis ; 39(10): 1907-1914, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32483685

RESUMO

The urgent need for rapid antimicrobial susceptibility is broadly apparent from government reports to the lay press. Accordingly, we developed a flow-cytometry assay (FCM) for evaluating ceftolozane-tazobactam (C/T) susceptibility directly on blood cultures (BC) requiring < 2 h from flag positivity to report. The protocol was optimized with C/T-susceptible and C/T-resistant gram-negative bacilli inoculated in BC aerobic bottles (Becton-Dickinson, USA), and afterward optimized for different C/T concentrations (1/4, 2/4, 4/4, and 8/4 mg/L) for 1 h incubation (37 °C), followed by FCM and software analysis. Fluorescent membrane permeability and membrane potential dyes were comparatively used to detect early cell lesions using the CytoFLEX cytometer (Beckman-Coulter, USA). Repeatability, reproducibility, and stability of the assay up to 48 h after BC positivity were determined. Internal validation was performed in spiked BC bottles with 130 Enterobacterales and 32 Pseudomonas aeruginosa isolates from Porto University (Portugal), including 13 ATCC isolates. Additionally, 64 gram-negative bacilli recovered from positive BC at Ramon y Cajal Hospital (Madrid, Spain) were tested. Categorical agreement (CA) and analytical errors were calculated comparing FCM with broth microdilution results. Only the membrane potential dyes clearly distinguished CT-susceptible and CT-resistant isolates. Excellent repeatability, reproducibility, and inter-method concordance was observed. Overall, CA was 99.1% using EUCAST criteria with 2 major errors and 98.7% with CLSI criteria with 2 major and 1 minor errors. A new, accurate, and ultra-rapid FCM (< 2 h) for testing C/T susceptibility gave accurate results and would expand current FCM antimicrobial susceptibility assay.


Assuntos
Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/diagnóstico , Bactérias Gram-Positivas/isolamento & purificação , Infecções por Bactérias Gram-Positivas/diagnóstico , Testes de Sensibilidade Microbiana , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Hemocultura , Cefalosporinas/farmacologia , Cefalosporinas/uso terapêutico , Citometria de Fluxo , Bactérias Gram-Negativas/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Bactérias Gram-Positivas/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Portugal , Espanha , Tazobactam/farmacologia , Tazobactam/uso terapêutico
3.
Artigo em Inglês | MEDLINE | ID: mdl-30348666

RESUMO

Candida glabrata is an emerging fungal pathogen. Its increased prevalence is associated with its ability to rapidly develop antifungal drug resistance, particularly to azoles. In order to unravel new molecular mechanisms behind azole resistance, a transcriptomics analysis of the evolution of a C. glabrata clinical isolate (isolate 044) from azole susceptibility to posaconazole resistance (21st day), clotrimazole resistance (31st day), and fluconazole and voriconazole resistance (45th day), induced by longstanding incubation with fluconazole, was carried out. All the evolved strains were found to accumulate lower concentrations of azole drugs than the parental strain, while the ergosterol concentration remained mostly constant. However, only the population displaying resistance to all azoles was found to have a gain-of-function mutation in the C. glabrataPDR1 gene, leading to the upregulation of genes encoding multidrug resistance transporters. Intermediate strains, exhibiting posaconazole/clotrimazole resistance and increased fluconazole/voriconazole MIC levels, were found to display alternative ways to resist azole drugs. Particularly, posaconazole/clotrimazole resistance after 31 days was correlated with increased expression of adhesin genes. This finding led us to identify the Epa3 adhesin as a new determinant of azole resistance. Besides being required for biofilm formation, Epa3 expression was found to decrease the intracellular accumulation of azole antifungal drugs. Altogether, this work provides a glimpse of the transcriptomics evolution of a C. glabrata population toward multiazole resistance, highlighting the multifactorial nature of the acquisition of azole resistance and pointing out a new player in azole resistance.


Assuntos
Antifúngicos/farmacologia , Azóis/farmacologia , Candida glabrata/efeitos dos fármacos , Candida glabrata/genética , Farmacorresistência Fúngica/genética , Candida glabrata/isolamento & purificação , Clotrimazol/farmacologia , Ergosterol/metabolismo , Fluconazol/farmacologia , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteínas de Membrana Transportadoras/genética , Testes de Sensibilidade Microbiana , Fatores de Transcrição/genética , Transcriptoma/genética , Triazóis/farmacologia , Voriconazol/farmacologia
4.
Mycoses ; 62(10): 932-936, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31278884

RESUMO

The immediate immune response developed by the keratinocytes against Malassezia yeasts has been addressed yielding conflicting results. This study aims the assessment of cytokines and antimicrobial peptides gene expression elicited by M. sympodialis and M. furfur once in contact with a reconstructed human epidermis. A yeast suspension was prepared in RPMI 1640 medium (Sigma-Aldrich, St. Louis, MO) supplemented with Tween 60 and oleic acid to obtain approximately 1 × 106 cells in a volume of 100 µL. Clinical isolates of M. sympodialis (from pityriasis versicolor) and M. furfur (from seborrhoeic dermatitis) were inoculated, separately, onto a reconstructed human epidermis. A distinct expression pattern was found between the two tested species, with a tendency for overexpression of pro-inflammatory cytokines very soon after infection, whereas no significant expression or gene downregulation was often noticed following 24 and 48 h of incubation. A possible Malassezia species-dependent immune response pattern is highlighted.


Assuntos
Epiderme/imunologia , Epiderme/microbiologia , Interações Hospedeiro-Patógeno , Queratinócitos/imunologia , Queratinócitos/microbiologia , Malassezia/crescimento & desenvolvimento , Malassezia/imunologia , Peptídeos Catiônicos Antimicrobianos/análise , Citocinas/análise , Dermatomicoses/microbiologia , Dermatomicoses/patologia , Humanos , Modelos Teóricos
5.
Mycoses ; 62(12): 1194-1201, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31556177

RESUMO

BACKGROUND: Biofilm formation represents a major microbial virulence attribute especially at epithelial surfaces such as the skin. Malassezia biofilm formation at the skin surface has not yet been addressed. OBJECTIVE: The present study aimed to evaluate Malassezia colonisation pattern on a reconstructed human epidermis (RhE) by imaging techniques. METHODS: Malassezia clinical isolates were previously isolated from volunteers with pityriasis versicolor and seborrhoeic dermatitis. Yeast of two strains of M furfur and M sympodialis were inoculated onto the SkinEthic™ RHE. The tissues were processed for light microscopy, wide-field fluorescence microscopy and scanning electron microscopy. RESULTS: Colonisation of the RhE surface with aggregates of Malassezia yeast entrapped in a multilayer sheet with variable amount of extracellular matrix was unveiled by imaging techniques following 24, 48, 72 and 96 hours of incubation. Whenever yeast were suspended in RPMI medium supplemented with lipids, the biofilm substantially increased with a dense extracellular matrix in which the yeast cells were embedded. Slight differences were found in the biofilm architectural structure between the two tested species with an apparently higher entrapment and viscosity in M furfur biofilm. CONCLUSION: Skin isolates of M furfur and M sympodialis were capable of forming biofilm in vitro at the epidermal surface simulating in vivo conditions. Following 24 hours of incubation, without added lipids, rudimental matrix was barely visible, conversely to the reported at plastic surfaces. The amount of biofilm apparently increased progressively from 48 to 96 hours. A structural heterogeneity of biofilm between species was found.


Assuntos
Biofilmes , Epiderme/microbiologia , Processamento de Imagem Assistida por Computador , Malassezia/isolamento & purificação , Pele Artificial/microbiologia , Dermatite Seborreica/microbiologia , Humanos , Malassezia/ultraestrutura , Microscopia Eletrônica de Varredura , Tinha Versicolor/microbiologia
6.
Antimicrob Agents Chemother ; 60(6): 3824-6, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27021318

RESUMO

A flow cytometry test was developed to identify carbapenemase production by Enterobacteriaceae and to discriminate between the different types of carbapenemases (classes A, B, and D). It is based on the detection of meropenem activity against bacteria, coupled with different carbapenemase inhibitors, which is assessed by flow cytometry. It represents a convenient, fast, and reliable approach (100% sensitivity and 100% specificity) for the detection and characterization of different carbapenemases.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/classificação , Enterobacteriaceae/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Citometria de Fluxo/métodos , Tienamicinas/farmacologia , beta-Lactamases/classificação , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Ácidos Borônicos/farmacologia , Cloxacilina/farmacologia , Ácido Edético/farmacologia , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , Enterobacteriaceae/crescimento & desenvolvimento , Infecções por Enterobacteriaceae/microbiologia , Expressão Gênica , Humanos , Meropeném , Penicilinas/farmacologia , beta-Lactamases/genética , beta-Lactamases/metabolismo
7.
Antimicrob Agents Chemother ; 59(10): 6629-33, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26248365

RESUMO

Candida parapsilosis is the second most prevalent fungal agent causing bloodstream infections. Nevertheless, there is little information about the molecular mechanisms underlying azole resistance in this species. Mutations (G1747A, A2619C, and A3191C) in the MRR1 transcription factor gene were identified in fluconazole- and voriconazole-resistant strains. Independent expression of MRR1 genes harboring these mutations showed that G1747A (G583R) and A2619C (K873N) are gain-of-function mutations responsible for azole resistance, the first described in C. parapsilosis.


Assuntos
Fluconazol/farmacologia , Proteínas Fúngicas/genética , Fatores de Transcrição/genética , Voriconazol/farmacologia , Candida/efeitos dos fármacos , Candida/genética , Farmacorresistência Fúngica , Proteínas Fúngicas/fisiologia , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Regulação Fúngica da Expressão Gênica/genética , Dados de Sequência Molecular , Mutação/genética , Fatores de Transcrição/fisiologia
8.
Antimicrob Agents Chemother ; 59(7): 4289-92, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25845879

RESUMO

Candida albicans is the most prevalent cause of fungemia worldwide. Its ability to develop resistance in patients receiving azole antifungal therapy is well documented. In a murine model of systemic infection, we show that ibuprofen potentiates fluconazole antifungal activity against a fluconazole-resistant strain, drastically reducing the fungal burden and morbidity. The therapeutic combination of fluconazole with ibuprofen may constitute a new approach for the management of antifungal therapeutics to reverse the resistance conferred by efflux pump overexpression.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Antifúngicos/uso terapêutico , Candidíase/tratamento farmacológico , Fluconazol/uso terapêutico , Ibuprofeno/uso terapêutico , Animais , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Candidíase/microbiologia , Farmacorresistência Fúngica/genética , Sinergismo Farmacológico , Feminino , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana
9.
J Antimicrob Chemother ; 70(4): 1083-93, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25558078

RESUMO

OBJECTIVES: The objective of this study was to clarify the antifungal properties of cerium, a lanthanide member, against Candida species. A comprehensive study with planktonic and sessile cells was performed. The ability of cerium nitrate (CN) to impair in vitro and in vivo biofilm formation was evaluated and its potential use in biofilm treatment was also evaluated. METHODS: Forty-eight clinical isolates of different Candida species and the type strain ATCC 90028 were tested according to the protocol M27-A3. The MICs and minimum lethal concentrations were determined. A time-kill assay was performed and a cytometric kinetic study was performed using live/dead markers. Biofilm inhibition and biofilm susceptibility in the presence of cerium was evaluated by quantification of the biofilm metabolic activity and total biomass with XTT and crystal violet assays, respectively. CN in vivo efficacy as a coating for medical indwelling devices was evaluated for the first time for Candida parapsilosis, using a mouse subcutaneous foreign body model using polyurethane catheter segments. Scanning electron microscopy was used to assess biofilm architecture after CN treatment. RESULTS: The MICs for planktonic cells correlated with severe cellular metabolic activity impairment and membrane damage after 3 h of incubation. Moreover, CN efficiently prevented biofilm formation both in vitro and in vivo in segments of polyurethane catheters. At higher concentrations, it was also able to disorganize and almost eradicate preformed biofilms. CONCLUSIONS: Our results strongly suggest that CN application in the clinical setting might be effective in preventing the formation of biofilm-associated infections, namely through catheter coating and ultimately as an antimicrobial lock therapy.


Assuntos
Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Candida/fisiologia , Cério/farmacologia , Animais , Candida/isolamento & purificação , Candidíase/microbiologia , Catéteres/microbiologia , Feminino , Corpos Estranhos/microbiologia , Violeta Genciana/metabolismo , Humanos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Coloração e Rotulagem , Sais de Tetrazólio/metabolismo
10.
BMC Microbiol ; 14: 155, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24920078

RESUMO

BACKGROUND: The purpose of this study was to unveil whether azole antifungals used in agriculture, similar to the clinical azoles used in humans, can evoke resistance among relevant human pathogens like Aspergillus fumigatus, an ubiquitous agent in nature. Additionally, cross-resistance with clinical azoles was investigated. Antifungal susceptibility testing of environmental and clinical isolates of A. fumigatus was performed according to the CLSI M38-A2 protocol. In vitro induction assays were conducted involving daily incubation of susceptible A. fumigatus isolates, at 35°C and 180 rpm, in fresh GYEP broth medium supplemented with Prochloraz (PCZ), a potent agricultural antifungal, for a period of 30 days. Minimal inhibitory concentrations (MIC) of PCZ and clinical azoles were monitored every ten days. In order to assess the stability of the developed MIC, the strains were afterwards sub-cultured for an additional 30 days in the absence of antifungal. Along the in vitro induction process, microscopic and macroscopic cultural observations were registered. RESULTS: MIC of PCZ increased 256 times after the initial exposure; cross-resistance to all tested clinical azoles was observed. The new MIC value of agricultural and of clinical azoles maintained stable in the absence of the selective PCZ pressure. PCZ exposure was also associated to morphological colony changes: macroscopically the colonies became mostly white, losing the typical pigmentation; microscopic examination revealed the absence of conidiation. CONCLUSIONS: PCZ exposure induced Aspergillus fumigatus morphological changes and an evident increase of MIC value to PCZ as well as the development of cross-resistance with posaconazole, itraconazole and voriconazole.


Assuntos
Aspergillus fumigatus/efeitos dos fármacos , Azóis/farmacologia , Farmacorresistência Fúngica , Fungicidas Industriais/farmacologia , Imidazóis/farmacologia , Aspergilose/microbiologia , Aspergillus fumigatus/crescimento & desenvolvimento , Aspergillus fumigatus/isolamento & purificação , Meios de Cultura/química , Microbiologia Ambiental , Humanos , Testes de Sensibilidade Microbiana , Mutação , Inoculações Seriadas , Temperatura
11.
FEMS Yeast Res ; 14(7): 1119-23, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25132632

RESUMO

Acquisition of azole resistance by clinically relevant yeasts in nature may result in a significant, yet undetermined, impact in human health. The main goal of this study was to assess the development of cross-resistance between agricultural and clinical azoles by Candida spp. An in vitro induction assay was performed, for a period of 90 days, with prochloraz (PCZ) - an agricultural antifungal. Afterward, the induced molecular resistance mechanisms were unveiled. MIC value of PCZ increased significantly in all Candida spp. isolates. However, only C. glabrata developed cross-resistance to fluconazole and posaconazole. The increased MIC values were stable. Candida glabrata azole resistance acquisition triggered by PCZ exposure involved the upregulation of the ATP binding cassette multidrug transporter genes and the transcription factor, PDR1. Single mutation previously implicated in azole resistance was found in PDR1 while ERG11 showed several synonymous single nucleotide polymorphisms. These results might explain why C. glabrata is so commonly less susceptible to clinical azoles, suggesting that its exposure to agricultural azole antifungals may be associated to the emergence of cross-resistance. Such studies forward potential explanations for the worldwide increasing clinical prevalence of C. glabrata and the associated worse prognosis of an infection by this species.


Assuntos
Antifúngicos/farmacologia , Candida glabrata/efeitos dos fármacos , Farmacorresistência Fúngica , Fungicidas Industriais/farmacologia , Imidazóis/farmacologia , Triazóis/farmacologia , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Fluconazol/farmacologia , Testes de Sensibilidade Microbiana , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
12.
Cytometry A ; 83(3): 324-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23359335

RESUMO

The conventional methods used to evaluate chitin content in fungi, such as biochemical assessment of glucosamine release after acid hydrolysis or epifluorescence microscopy, are low throughput, laborious, time-consuming, and cannot evaluate a large number of cells. We developed a flow cytometric assay, efficient, and fast, based on Calcofluor White staining to measure chitin content in yeast cells. A staining index was defined, its value was directly related to chitin amount and taking into consideration the different levels of autofluorecence. Twenty-two Candida spp. and four Cryptococcus neoformans clinical isolates with distinct susceptibility profiles to caspofungin were evaluated. Candida albicans clinical isolate SC5314, and isogenic strains with deletions in chitin synthase 3 (chs3Δ/chs3Δ) and genes encoding predicted GlycosylPhosphatidylInositol (GPI)-anchored proteins (pga31Δ/Δ and pga62Δ/Δ), were used as controls. As expected, the wild-type strain displayed a significant higher chitin content (P < 0.001) than chs3Δ/chs3Δ and pga31Δ/Δ especially in the presence of caspofungin. Ca. parapsilosis, Ca. tropicalis, and Ca. albicans showed higher cell wall chitin content. Although no relationship between chitin content and antifungal drug susceptibility phenotype was found, an association was established between the paradoxical growth effect in the presence of high caspofungin concentrations and the chitin content. This novel flow cytometry protocol revealed to be a simple and reliable assay to estimate cell wall chitin content of fungi.


Assuntos
Candida/química , Parede Celular/química , Quitina/análise , Cryptococcus neoformans/química , Citometria de Fluxo/métodos , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candida/genética , Candida/ultraestrutura , Caspofungina , Quitina Sintase/genética , Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/ultraestrutura , Farmacorresistência Fúngica , Equinocandinas/farmacologia , Fluorescência , Proteínas Fúngicas/genética , Proteínas Ligadas por GPI/genética , Glicosilfosfatidilinositóis/análise , Lipopeptídeos , Deleção de Sequência , Coloração e Rotulagem
13.
J Fungi (Basel) ; 9(1)2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36675901

RESUMO

Candida parapsilosis is the second most common Candida species isolated in Asia, Southern Europe, and Latin America and is often involved in invasive infections that seriously impact human health. This pathogen is part of the psilosis complex, which also includes Candida orthopsilosis and Candida metapsilosis. C. parapsilosis infections are particularly prevalent among neonates with low birth weights, individuals who are immunocompromised, and patients who require prolonged use of a central venous catheter or other indwelling devices, whose surfaces C. parapsilosis exhibits an enhanced capacity to adhere to and form biofilms. Despite this well-acknowledged prevalence, the biology of C. parapsilosis has not been as extensively explored as that of Candida albicans. In this paper, we describe the molecular mechanistic pathways of virulence in C. parapsilosis and show how they differ from those of C. albicans. We also describe the mode of action of antifungal drugs used for the treatment of Candida infections, namely, polyenes, echinocandins, and azoles, as well as the resistance mechanisms developed by C. parapsilosis to overcome them. Finally, we stress the importance of the ongoing search for species-specific features that may aid the development of effective control strategies and thus reduce the burden on patients and healthcare costs.

14.
FEMS Yeast Res ; 12(4): 423-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22268592

RESUMO

Our aim was to detect the presence of an alternative oxidase (AOX) in Candida krusei clinical strains and its influence on fluconazole susceptibility and in reactive oxygen species (ROS) production. Candida krusei clinical isolates were tested to evaluate the presence of AOX. Debaromyces hansenii 2968 (AOX positive) and Saccharomyces cerevisiae BY4742 (AOX negative) were used as control strains. Measurements of oxygen consumption were performed in the presence of 1 mM KCN, an inhibitor of the classical respiratory chain, and 5 mM salicylhydroxamic acid (SHAM). AOX expression was monitored by Western blotting using an AOX monoclonal antibody. Interactions between fluconazole and SHAM were performed using checkerboard assay. ROS production was evaluated in the presence of SHAM plus fluconazole, H(2) O(2) , menadione, or plumbagin. AOX was present in all C. krusei tested. The combination of fluconazole with SHAM resulted in an indifferent effect. In the presence of SHAM, the treatment with ROS inductors or fluconazole increased ROS production, except in the AOX-negative strain. An alternative respiratory pathway resistant to cyanide is described for the first time as a characteristic of C. krusei species. This AOX is unrelated to fluconazole resistance; however, it protects C. krusei from oxidative stress.


Assuntos
Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candida/metabolismo , Fluconazol/farmacologia , Redes e Vias Metabólicas/genética , Estresse Oxidativo , Oxigênio/metabolismo , Western Blotting , Candida/enzimologia , Candida/isolamento & purificação , Candidíase/microbiologia , Debaryomyces/efeitos dos fármacos , Perfilação da Expressão Gênica , Humanos , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Oxidantes/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos
15.
J Burn Care Res ; 43(2): 336-342, 2022 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-34523679

RESUMO

Burn wound infections are often the source of bacteria responsible for systemic infections, including bloodstream infections and pneumonia that ultimately can result in multisystem organ failure and death. Any rapid change in the burn wound appearance or the clinical condition of the burn patient may herald burn wound infection or sepsis. The revival of phage therapy, either in single mode or in combination with conventional antibiotics may represent a valuable alternative, to treat specific bacterial infections such as burn wound infections, including those caused by multidrug-resistant organisms. This systematic review addresses the: 1) general characteristics of bacteriophages; 2) activity of bacteriophages vs conventional antibiotics; 3) activity of bacteriophages against biofilms; 4) bacteriophage administration; and 5) use of bacteriophages in burn wound infections. Although several scientific organizations/societies recognized that phage therapy could be of key value in modern wound care, specific aspects are critical for a burn surgeon and might represent pitfalls discouraging phage therapy adoption in burn wound management; in particular, the unavailability of consensual therapeutic guidelines/regulatory policies and the lack of laboratorial support that might be predictive of its efficacy. The availability of a product/formulation convenient to use, with adequate stability and shelf half-life is also a key condition.


Assuntos
Bacteriófagos , Queimaduras , Terapia por Fagos , Infecção dos Ferimentos , Antibacterianos/uso terapêutico , Queimaduras/complicações , Queimaduras/microbiologia , Queimaduras/terapia , Humanos , Infecção dos Ferimentos/tratamento farmacológico
16.
Clin Microbiol Infect ; 28(12): 1655.e5-1655.e8, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36028086

RESUMO

OBJECTIVES: Hereby, we describe the molecular mechanisms underlying the acquisition of azole resistance by a Candida parapsilosis isolate following fluconazole treatment due to candiduria. METHODS: A set of three consecutive C. parapsilosis isolates were recovered from the urine samples of a patient with candiduria. Whole-genome sequencing and antifungal susceptibility assays were performed. The expression of MRR1, MDR1, ERG11 and CDR1B (CPAR2_304370) was quantified by RT-qPCR. RESULTS: The initial isolate CPS-A was susceptible to all three azoles tested (fluconazole, voriconazole and posaconazole); isolate CPS-B, collected after the second cycle of treatment, exhibited a susceptible-dose-dependent phenotype to fluconazole and isolate CPS-C, recovered after the third cycle, exhibited a cross-resistance profile to fluconazole and voriconazole. Whole-genome sequencing revealed a putative resistance mechanism in isolate CPS-C, associated with a G1810A nucleotide substitution, leading to a G604R change in the Mrr1p transcription factor. Introducing this mutation into the susceptible CPS-A isolate (MRR1RI) resulted in resistance to fluconazole and voriconazole, as well as up-regulation of MRR1 and MDR1. Interestingly, the susceptible-dose-dependent phenotype exhibited by isolate CPS-B was associated with an increased copy number of the CDR1B gene. The expression of CDR1B was increased in both isolates CPS-B and CPS-C and in the MRR1RI strain, harbouring the gain-of-function mutation. CONCLUSIONS: Our results describe clinical azole cross-resistance acquisition in C. parapsilosis due to a G1810A (G604R) gain-of-function mutation, resulting in MRR1 hyperactivation and consequently, MDR1 efflux pump overexpression. We also associated amplification of the CDR1B gene with decreased fluconazole susceptibility and showed that it is a putative target of the MRR1 gain-of-function mutation.


Assuntos
Candida parapsilosis , Candidíase , Candida parapsilosis/genética , Azóis/farmacologia , Azóis/uso terapêutico , Fluconazol/farmacologia , Fluconazol/uso terapêutico , Voriconazol/farmacologia , Voriconazol/uso terapêutico , Farmacorresistência Fúngica/genética , Mutação com Ganho de Função , Testes de Sensibilidade Microbiana , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Candidíase/tratamento farmacológico , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Mutação
17.
Commun Biol ; 5(1): 1118, 2022 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-36271293

RESUMO

The increasing prevalence of candidosis caused by Candida glabrata is related to its ability to acquire azole resistance. Although azole resistance mechanisms are well known, the mechanisms for azole import into fungal cells have remained obscure. In this work, we have characterized two hexose transporters in C. glabrata and further investigate their role as potential azole importers. Three azole susceptible C. glabrata clinical isolates were evolved towards azole resistance and the acquired resistance phenotype was found to be independent of CgPDR1 or CgERG11 mutations. Through whole-genome sequencing, CgHXT4/6/7 was found to be mutated in the three evolved strains, when compared to their susceptible parents. CgHxt4/6/7 and the 96% identical CgHxt6/7 were found to confer azole susceptibility and increase azole accumulation in C. glabrata cells, strikingly rescuing the susceptibility phenotype imposed by CgPDR1 deletion, while the identified loss-of-function mutation in CgHXT4/6/7, leads to increased azole resistance. In silico docking analysis shows that azoles display a strong predicted affinity for the glucose binding site of CgHxt4/6/7. Altogether, we hypothesize that hexose transporters, such as CgHxt4/6/7 and CgHxt6/7, may constitute a family of azole importers, involved in clinical drug resistance in fungal pathogens, and constituting promising targets for improved antifungal therapy.


Assuntos
Azóis , Candida glabrata , Candida glabrata/genética , Azóis/farmacologia , Azóis/uso terapêutico , Farmacorresistência Fúngica/genética , Antifúngicos/farmacologia , Glucose , Evolução Molecular , Hexoses
19.
Virulence ; 12(1): 601-614, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33538224

RESUMO

Candida parapsilosis is an emergent opportunistic yeast among hospital settings that affects mainly neonates and immunocompromised patients. Its most remarkable virulence traits are the ability to adhere to prosthetic materials, as well as the formation of biofilm on abiotic surfaces. The Ndt80 transcription factor was identified as one of the regulators of biofilm formation by C. parapsilosis; however, its function in this process was not yet clarified. By knocking out NDT80 (CPAR2-213640) gene, or even just one single copy of the gene, we observed substantial alterations of virulence attributes, including morphogenetic changes, adhesion and biofilm growth profiles. Both ndt80Δ and ndt80ΔΔ mutants changed colony and cell morphologies from smooth, yeast-shaped to crepe and pseudohyphal elongated forms, exhibiting promoted adherence to polystyrene microspheres and notably, forming a higher amount of biofilm compared to wild-type strain. Interestingly, we identified transcription factors Ume6, Cph2, Cwh41, Ace2, Bcr1, protein kinase Mkc1 and adhesin Als7 to be under Ndt80 negative regulation, partially explaining the phenotypes displayed by the ndt80ΔΔ mutant. Furthermore, ndt80ΔΔ pseudohyphae adhered more rapidly and were more resistant to murine macrophage attack, becoming deleterious to such cells after phagocytosis. Unexpectedly, our findings provide the first evidence for a direct role of Ndt80 as a repressor of C. parapsilosis virulence attributes. This finding shows that C. parapsilosis Ndt80 functionally diverges from its homolog in the close related fungal pathogen C. albicans.


Assuntos
Biofilmes/crescimento & desenvolvimento , Candida parapsilosis/genética , Candida parapsilosis/patogenicidade , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Fenótipo , Fatores de Transcrição/genética , Animais , Candidíase/microbiologia , Humanos , Macrófagos/microbiologia , Camundongos , Fagocitose , Células RAW 264.7
20.
J Burn Care Res ; 42(2): 232-235, 2021 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32844994

RESUMO

Burns injuries during pregnancy are rarely reported in developed countries, but an increasing in mortality and morbidity has been observed. The authors describe their experience in the treatment of pregnant women in a burn unit. A 12-year retrospective study of burns in pregnant women hospitalized was conducted. Since 2008, two pregnant women were admitted in their unit. Patient 1, a 32-year-old pregnant woman on second trimester (27s6d), suffered a second-degree burn injury, 16% total body surface area (TBSA), caused by fire. She was admitted in their burn unit and submitted to medical treatment, wound dressing, and surgical treatment. Cerium nitrate and silver sulfadiazine were used in burn lesions and the patient was submitted to debridement and skin graft surgery. No uneventful events occurred with the fetus. Patient 2 was a 32-year-old pregnant woman on second trimester (26s), HVC positive, admitted with a second-degree flash burn, 8% TBSA. She was submitted to endotracheal intubation before arriving to the hospital due to risk of airway burn. Dexamethasone was administered for fetus lung maturation. No uneventful events were observed. The incidence of thermal injury in pregnancy in Portugal is low. Active medical treatment together with conservative wound care should be the standard in each trimester of pregnancy. Although there is limited safety information on cerium nitrate or silver sulfadiazine during pregnancy, those were used with no adverse effects on one of their patients. Obstetrical management should be individualized.


Assuntos
Anti-Infecciosos Locais/uso terapêutico , Queimaduras/terapia , Complicações na Gravidez/etiologia , Complicações na Gravidez/terapia , Adulto , Queimaduras/complicações , Feminino , Humanos , Portugal , Gravidez , Complicações na Gravidez/patologia , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Estudos Retrospectivos , Sulfadiazina de Prata/uso terapêutico , Resultado do Tratamento , Cicatrização
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