Natália Faria

New University of Lisbon, Lisboa, Lisbon, Portugal

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Publications (16)37.21 Total impact

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    ABSTRACT: Cryptococcosis caused by the fungus Cryptococcus neoformans is an opportunistic mycosis, infecting mainly immunodepressed individuals. Molecular epidemiology studies of cryptococcosis in Europe are limited. This paper presents a retrospective study of cryptococcosis in 105 cryptococcal isolates from two hospitals in Lisbon, Portugal, among HIV/AIDS patients, from 1991 to 2007. Among these patients, the number of cases of cryptococcosis increased from 5.1 to 6.9 cases per year from the pre- to post-highly active antiretroviral therapy (HAART) era. As expected, the median age of the patients increased, from 32 (mean: 33 ± 8) to 39 (mean: 41 ± 10) years, and the ratio of male to female patients remained high (7.7 and 7.6, respectively). Strain genotyping based on restriction fragment length polymorphism of the orotidine monophosphate pyrophosphorylase (URA5-RFLP) gene showed that, in general, the relative frequencies of the genotypes VNI-IV are similar to those from other European countries. These frequencies were, respectively, for the pre- and post-HAART periods: 41.7 and 43.5 % for VNI; 2.8 and 17.4 % for VNII; 38.9 and 30.4 % for VNIII; 16.7 and 7.2 % for VNIV and 0 and 1.4 % for VGII. Some apparent although statistically insignificant differences among these values were observed between both periods. The genotypic frequencies were not also statistically different according to the patients' gender or age range. Of note are the high proportion of VNIII isolates (common in Europe) and the high increase in the frequency of the VNII genotype in the post-HAART. Ultimately, these results may have implications in disease therapy, management and control.
    Current Microbiology 07/2015; 71(4). DOI:10.1007/s00284-015-0873-z · 1.36 Impact Factor
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    ABSTRACT: Beaches worldwide provide recreational opportunities to hundreds of millions of people and serve as important components of coastal economies. Beach water is often monitored for microbiological quality to detect the presence of indicators of human sewage contamination so as to prevent public health outbreaks associated with water contact. However, growing evidence suggests that beach sand can harbor microbes harmful to human health, often in concentrations greater than the beach water. Currently, there are no standards for monitoring, sampling, analyzing, or managing beach sand quality. In addition to indicator microbes, growing evidence has identified pathogenic bacteria, viruses, and fungi in a variety of beach sands worldwide. The public health threat associated with these populations through direct and indirect contact is unknown because so little research has been conducted relating to health outcomes associated with sand quality. In this manuscript, we present the consensus findings of a workshop of experts convened in Lisbon, Portugal to discuss the current state of knowledge on beach sand microbiological quality and to develop suggestions for standardizing the evaluation of sand at coastal beaches. The expert group at the "Microareias 2012" workshop recommends that 1) beach sand should be screened for a variety of pathogens harmful to human health, and sand monitoring should then be initiated alongside regular water monitoring; 2) sampling and analysis protocols should be standardized to allow proper comparisons among beach locations; and 3) further studies are needed to estimate human health risk with exposure to contaminated beach sand. Much of the manuscript is focused on research specific to Portugal, but similar results have been found elsewhere, and the findings have worldwide implications.
    Science of The Total Environment 12/2013; 472C:1062-1069. DOI:10.1016/j.scitotenv.2013.11.091 · 4.10 Impact Factor
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    ABSTRACT: Enhanced control of species of Cryptococcus, non-fermentative yeast pathogens, was achieved by chemosensitization through co-application of certain compounds with a conventional antimicrobial drug. The species of Cryptococcus tested showed higher sensitivity to mitochondrial respiratory chain (MRC) inhibition compared to species of Candida. This higher sensitivity results from the inability of Cryptococcus to generate cellular energy through fermentation. To heighten disruption of cellular MRC, octyl gallate (OG) or 2,3-dihydroxybenzaldehyde (2,3-DHBA), phenolic compounds inhibiting mitochondrial functions, were selected as chemosensitizers to pyraclostrobin (PCS; an inhibitor of complex III of MRC). The cryptococci were more susceptible to the chemosensitization (i.e., PCS + OG or 2,3-DHBA) than the Candida with all Cryptococcus strains tested being sensitive to this chemosensitization. Alternatively, only few of the Candida strains showed sensitivity. OG possessed higher chemosensitizing potency than 2,3-DHBA, where the concentration of OG required with the drug to achieve chemosensitizing synergism was much lower than that required of 2,3-DHBA. Bioassays with gene deletion mutants of the model yeast Saccharomyces cerevisiae showed that OG or 2,3-DHBA affect different cellular targets. These assays revealed mitochondrial superoxide dismutase or glutathione homeostasis plays a relatively greater role in fungal tolerance to 2,3-DHBA or OG, respectively. These findings show that application of chemosensitizing compounds that augment MRC debilitation is a promising strategy to antifungal control against yeast pathogens.
    Molecules 08/2013; 18(8):8873-94. DOI:10.3390/molecules18088873 · 2.42 Impact Factor
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    ABSTRACT: K.L.C.); noreen.mahoney@ars.usda.gov (N.M.); ykkim@kookmin.ac.kr (Y.K.K.); bruce.campbell@ars.usda.gov (B.C.C.) Abstract: Natural compounds that pose no significant medical or environmental side effects are potential sources of antifungal agents, either in their nascent form or as structural backbones for more effective derivatives. Kojic acid (KA) is one such compound. It is a natural by-product of fungal fermentation commonly employed by food and cosmetic industries. We show that KA greatly lowers minimum inhibitory (MIC) or fungicidal (MFC) concentrations of commercial medicinal and agricultural antifungal agents, amphotericin B (AMB) and strobilurin, respectively, against pathogenic yeasts and filamentous fungi. Assays using two mitogen-activated protein kinase (MAPK) mutants, i.e., sakA∆, mpkC∆, of Aspergillus fumigatus, an agent for human invasive aspergillosis, with hydrogen peroxide (H 2 O 2) or AMB indicate such chemosensitizing activity of KA is most conceivably through disruption of fungal antioxidation systems. KA could be developed as a chemosensitizer to enhance efficacy of certain conventional antifungal drugs or fungicides.
    International Journal of Molecular Sciences 12/2012; 13(12):13867-13880. DOI:10.3390/ijms131113867 · 2.86 Impact Factor
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    ABSTRACT: In addition to the fungal cellular membrane, the cellular antioxidant system can also be a viable target in the antifungal action of amphotericin B (AMB). Co-application of certain redox-potent natural compounds with AMB actually increases efficacy of the drug through chemosensitization. Some redox-potent chemosensitizers and AMB perturb common cellular targets, resulting in synergistic inhibition of fungal growth. Chemosensitizing activities of four redox-potent benzaldehydes were tested against clinical and reference strains of Candida albicans, C. krusei, C. tropicalis, and Cryptococcus neoformans in combination with AMB, based on assays outlined by the European Committee on Antimicrobial Susceptibility Testing. Two dihydroxybenzaldehydes (DHBAs), i.e., 2,3-DHBA and 2,5-DHBA, significantly enhanced activity of AMB against most strains, as measured by lower minimum inhibitory concentrations and/or minimum fungicidal concentrations (MFCs). A non-hydroxylated benzaldehyde, trans-cinnamaldehyde, showed chemosensitizing activity through lower MFCs, only. Contrastingly, a methoxylated benzaldehyde (3,5-dimethoxybenzaldehyde) had no chemosensitizing activity, as all strains were hypertolerant to this compound. Bioassays using deletion mutants of the model yeast, Saccharomyces cerevisiae, indicated DHBAs exerted their chemosensitizing activity by targeting mitochondrial superoxide dismutase. This targeting, in turn, disrupted the ability of the yeast strains to respond to AMB-induced oxidative stress. These in vitro results indicate that certain DHBAs are potent chemosensitizing agents to AMB through co-disruption of the oxidative stress response capacity of yeasts. Such redox-potent compounds show promise for enhancing AMB-based antifungal therapy for candidiasis and cryptococcosis.
    Frontiers in Microbiology 07/2012; 3:261. DOI:10.3389/fmicb.2012.00261 · 3.94 Impact Factor
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    ABSTRACT: The cellular antioxidant system is a target in the antifungal action of amphotericin B (AMB) and itraconazole (ITZ), in filamentous fungi. The sakAΔ mutant of Aspergillus fumigatus, a mitogen-activated protein kinase (MAPK) gene deletion mutant in the antioxidant system, was found to be more sensitive to AMB or ITZ than other A. fumigatus strains, a wild type and a mpkCΔ mutant (a MAPK gene deletion mutant in the polyalcohol sugar utilization system). Complete fungal kill (≥99.9%) by ITZ or AMB was also achieved by much lower dosages for the sakAΔ mutant than for the other strains. It appears msnA, an Aspergillus ortholog to Saccharomyces cerevisiae MSN2 (encoding a stress-responsive C2H2-type zinc-finger regulator) and sakA and/or mpkC (upstream MAPKs) are in the same stress response network under tert-butyl hydroperoxide (t-BuOOH)-, hydrogen peroxide (H2O2)- or AMB-triggered toxicity. Of note is that ITZ-sensitive yeast pathogens were also sensitive to t-BuOOH, showing a connection between ITZ sensitivity and antioxidant capacity of fungi. Enhanced antifungal activity of AMB or ITZ was achieved when these drugs were co-applied with redox-potent natural compounds, 2,3-dihydroxybenzaldehyde, thymol or salicylaldehyde, as chemosensitizing agents. We concluded that redox-potent compounds, which target the antioxidant system in fungi, possess a chemosensitizing capacity to enhance efficacy of conventional drugs.
    Frontiers in Microbiology 03/2012; 3:88. DOI:10.3389/fmicb.2012.00088 · 3.94 Impact Factor
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    ABSTRACT: Determine whether certain, natural phenolic compounds enhance activity of commercial antifungal drugs against yeast strains of Candida and Cryptococcus neoformans. Twelve natural phenolics were examined for fungicidal activity against nine reference strains of Candida and one of C. neoformans. Six compounds were selected for synergistic enhancement of antifungal drugs, amphotericin B (AMB), fluconazole (FLU) and itraconazole (ITR). Matrix assays of phenolic and drug combinations conducted against one reference strain, each, of Candida albicans and C. neoformans showed cinnamic and benzoic acids, thymol, and 2,3- and 2,5-dihydroxybenzaldehydes (-DBA) had synergistic interactions depending upon drug and yeast strain. 2,5-DBA was synergistic with almost all drug and strain combinations. Thymol was synergistic with all drugs against Ca. albicans and with AMB in C. neoformans. Combinations of benzoic acid or thymol with ITR showed highest synergistic activity. Of 36 combinations of natural product and drug tested, none were antagonistic. Relatively nontoxic natural products can synergistically enhance antifungal drug activity, in vitro. This is a proof-of-concept, having clinical implications. Natural chemosensitizing agents could lower dosages needed for effective chemotherapy of invasive mycoses. Further studies against clinical yeast strains and use of animal models are warranted.
    Letters in Applied Microbiology 02/2011; 52(5):506-13. DOI:10.1111/j.1472-765X.2011.03032.x · 1.75 Impact Factor
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    ABSTRACT: A male patient from Guinea-Bissau was admitted to Egas Moniz Hospital, Lisbon, complaining of fever and exhibiting a productive cough with mucopurulent discharge and weight loss. He had been using empirical medication with dexamethasone to treat his generalized facial swelling. At admission, he was cachectic and presented with soft facial edema, oropharyngeal thrush, and two fistulas of the palate. Acid-fast bacilli were detected in the sputum and were later identified as Mycobacterium tuberculosis. Cultures of the palatine exudate and biopsy resulted in the growth of Candida albicans. The patient was administered antituberculosis drugs and fluconazole, but his clinical situation deteriorated progressively. Extensive investigation of his clinical condition did not result in a conclusive diagnosis until he began to experience respiratory distress and subcutaneous nodules appeared on his face. Biopsies of the hypopharynx and nodules revealed the presence of Conidiobolus coronatus. After initiating combined antifungal and antibiotic therapy, the patient's clinical condition improved significantly. We report an unusual presentation of entomophthoromycosis and describe the clinical difficulties that delayed this diagnosis.
    Medical mycology: official publication of the International Society for Human and Animal Mycology 12/2010; 48(8):1099-104. DOI:10.3109/13693786.2010.497973 · 2.26 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 05/2010; 41(21). DOI:10.1002/chin.201021122
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    ABSTRACT: We report here a simple entry into naphtho[2,3-d]isoxazole-4,9-dione system containing a EWG in position 3 using the readily available 2,3-dichloro-1,4-naphthoquinone and nitromethyl derivatives in the presence of base. Antifungal activity of synthesised naphthoquinones was evaluated against ATCC and PYCC reference strains of Candida. The results suggest that the naphtho[2,3-d]isoxazole-4,9-dione scaffold has the potential to be developed into novel and safe therapeutic antifungal agents.
    Bioorganic & medicinal chemistry letters 11/2009; 20(1):193-5. DOI:10.1016/j.bmcl.2009.10.137 · 2.33 Impact Factor
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    ABSTRACT: The aim of this study was to develop a PCR-based method of gene-directed multiplex PCR to rapidly identify microcystins producing cyanobacteria, regardless of their taxa, that could be applied in routine freshwater monitoring. Instead of using the amplification of only one or two mcy gene fragments, a multiplex PCR that simultaneously amplifies mcyA-cd, mcyAB, and mcyB fragments of the microcystin gene cluster was validated with DNA from 124 cyanobacterial isolates and applied in 37 environmental samples. The toxicological status of the isolates was assessed by high-performance liquid chromatography also used as the "gold standard" for the evaluation of multiplex mcy genes-based PCR, where a sensitivity of 92.3% and a specificity of 100% have been obtained. For the environmental samples, a rapid protocol for their direct use in the PCR reaction has been developed and, by using ELISA results as "gold standard" for the presence of microcystins in these samples, a sensitivity of 80% and a specificity of 100% were achieved, showing that this multiplex PCR test is a rapid, reliable, and economical way of assessing the microcystin-producing potential of cyanobacteria in freshwaters, regardless of their taxa or microcystins variant produced.
    Environmental Toxicology 06/2009; 25(3):251-60. DOI:10.1002/tox.20502 · 3.23 Impact Factor
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    ABSTRACT: In order to assess the potential of several molecular targets for the identification, typing and traceability of cyanobacteria in freshwater reservoirs, molecular techniques were applied to 118 cyanobacterial isolates mostly sourced from Portuguese freshwater reservoirs and representative of three orders of cyanobacteria: Chroococcales (54), Oscillatoriales (15) and Nostocales (49). The isolates were previously identified by morphological methods and subsequently characterized by composite hierarchical cluster analysis of STRR and LTRR (short and long tandemly repeated repetitive sequences) PCR fingerprinting profiles. Representative isolates were selected from each cluster and their molecular identification, at the species level, was obtained or confirmed by phylogenetic positioning using 16S rRNA gene and rpoC1 phylogenies. A highly congruent association was observed between STTR- and LTRR-based clusters and taxonomic affiliation, revealing the usefulness of such PCR fingerprinting profiles for the identification of cyanobacteria. Composite analysis of hierarchical clustering of M13 and ERIC PCR fingerprints also appeared suitable for strain typing and traceability within a reservoir, indicating its potential for use in cyanobacterial monitoring, as a quality management control. Based on Simpson (D) and Shannon-Wiener (J') indices a high diversity was observed within all species, with Planktothrix agardhii showing the lowest diversity values (D=0.83; J'=0.88) and Aphanizomenon flos-aquae the highest ones (D=J'=0.99). A diagnostic key based on 16S-ARDRA, ITS amplification and ITS-ARDRA for identification purposes is also presented.
    Microbiology 03/2009; 155(Pt 2):642-56. DOI:10.1099/mic.0.022848-0 · 2.84 Impact Factor
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    ABSTRACT: So far, the presence of microcystins in Portuguese freshwater resources has always been attributed to the bloom-forming cyanobacteria Microcystis aeruginosa. In 2005, however, microcystins were detected at the Beliche reservoir (Algarve, South Portugal), following the development of a bloom dominated by Planktothrix rubescens. The identity of the causative organism was confirmed by combining both morphological and 16S rRNA gene sequence analysis. Its ability to produce microcystins was confirmed by HPLC and MALDI-TOF MS. Unlike M. aeruginosa that usually accumulates near the water surface, P. rubescens found at the Beliche reservoir accumulated only at deep water levels. Being invisible from the surface, the occurrence of toxic P. rubescens in freshwater resources requires special attention when designing site inspection and sampling procedures for the correct risk assessment and management of cyanobacterial blooms in the field.
    Hydrobiologia 01/2009; 621:207-211. DOI:10.1007/s10750-008-9640-5 · 2.21 Impact Factor
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    ABSTRACT: This synthesis of 3 studies from 2 regions of southern Portugal (Alentejo and Algarve) was part of a workshop focusing on cyanobacteria held at the SAME 10. The first study monitored impacts of the large Alqueva dam on the Guadiana estuary since 1996, revealing changes in sediment load, nutrient regime and phytoplankton succession. Prior to dam construction, dense cyanobacterial blooms occurred in the upper estuary during summer and fall. After dam construction, chlorophyll concentration, phytoplankton diversity and abundances of cyanobacteria decreased, contrary to predictions. Mycrocystins remained at low levels in the seston and undetectable in water samples, except during summer 2003 when the particulate fraction contained 1 μg l–1, while chlorophyll concentrations and abundances of potentially toxic cyanobacteria remained low. Algarve reservoirs studied since 2001 revealed differences in phytoplankton dynamics. In the western mesotrophic reservoirs (Bravura and Funcho), 40 to 50% of surface samples contained cyanobacterial concentrations of ≥2000 cells ml–1, while over 80% of samples from the eastern oligotrophic reservoirs (Odeleite and Beliche) exceeded this value. Spring blooms were dominated by Oscillatoriales in Odeleite and Beliche and by Chroococcales in Bravura and Funcho. Bloom composition seemed to depend on water temperature and management strategies, while toxin concentrations reflected the increased biomass of toxic species. Finally, phytoplankton communities and microcystin production in 5 Alentejo freshwater reservoirs were studied from May to December 2005 and April to July 2006. Cyanobacterial blooms occurred, with varying intensities, not only during summer but also occasionally in winter. Microcystins were detected in 23% of the samples (n = 51), but without correlation with cyanobacterial biomass. Although Microcystis aeruginosa seemed to be the major producer of microcystins, other potentially toxic species were found. In summary, the varying pattern of cyanobacterial bloom occurrence and toxicity requires a systematic approach to monitoring programs for adequate risk assessment.
    Aquatic Microbial Ecology 09/2008; 53(1):129-140. DOI:10.3354/ame01228 · 1.90 Impact Factor
  • E. Valério · Natália Faria · Sérgio Paulino · P. Pereira
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    ABSTRACT: Toxic cyanobacteria are common in Portuguese freshwaters and are a cause of concern, given that exposure to subacute levels of cyanobacterial toxins through drinking and recreational water might have deleterious effects on human health. Since 1996 several laboratories have been involved in the screening of cyanotoxins in different freshwater bodies, some on a regularly basis but most on a sporadically basis. Here we present data on the phytoplankton communities and on microcystins production occurring in six freshwater reservoirs located in a dry region of south Portugal, from May to December 2005 and April to July 2006. Most of the reservoirs experienced cyanobacterial blooms of various intensities, following noticeable shifts in phytoplankton composition towards cyanobacterial dominance. The seasonal dominance of cyanobacteria during warmer periods was not a fi xed pattern since considerable amounts of cyanobacteria were also recorded during winter months in some reservoirs. Microcystins were detected in 23% of the 53 samples tested and some of them had concentrations higher than the WHO guideline of 1μg L-1 of microcystins, but their amounts not always refl ected the encountered cyanobacteria biomass. Although Microcystis aeruginosa seems to be the major species responsible for microcystins production, other potentially toxigenic bloom-forming species were also found. These results refl ect the irregular and unpredictable nature of cyanobacterial blooms in what respects to their occurrence, their composition, their intensity and persistency, as well as to their overall toxicity, strengthening the need of a systematic survey of freshwater resources for the correct risk assessment of cyanobacteria and associated toxins in natural environments.
    Annales de Limnologie - International Journal of Limnology 01/2008; 44:189-196. · 1.04 Impact Factor
  • E. Valério · N. Faria · S. Paulino · P. Pereira
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    ABSTRACT: Toxic cyanobacteria are common in Portuguese freshwaters and are a cause of concern, given that exposure to subacute levels of cyanobacterial toxins through drinking and recreational water might have deleterious effects on human health. Since 1996 several laboratories have been involved in the screening of cyanotoxins in different freshwater bodies, some on a regularly basis but most on a sporadically basis. Here we present data on the phytoplankton communities and on microcystins production occurring in six freshwater reservoirs located in a dry region of south Portugal, from May to December 2005 and April to July 2006. Most of the reservoirs experienced cyanobacterial blooms of various intensities, following noticeable shifts in phytoplankton composition towards cyanobacterial dominance. The seasonal dominance of cyanobacteria during warmer periods was not a fi xed pattern since considerable amounts of cyanobacteria were also recorded during winter months in some reservoirs. Microcystins were detected in 23% of the 53 samples tested and some of them had concentrations higher than the WHO guideline of 1μg L-1 of microcystins, but their amounts not always reflected the encountered cyanobacteria biomass. Although Microcystis aeruginosa seems to be the major species responsible for microcystins production, other potentially toxigenic bloom-forming species were also found. These results reflect the irregular and unpredictable nature of cyanobacterial blooms in what respects to their occurrence, their composition, their intensity and persistency, as well as to their overall toxicity, strengthening the need of a systematic survey of freshwater resources for the correct risk assessment of cyanobacteria and associated toxins in natural environments.
    Annales de Limnologie - International Journal of Limnology 12/2007; 44(03):189 - 196. DOI:10.1051/limn:2008003 · 1.04 Impact Factor

Publication Stats

133 Citations
37.21 Total Impact Points

Institutions

  • 2009–2013
    • New University of Lisbon
      • Institute of Hygiene and Tropical Medicine
      Lisboa, Lisbon, Portugal
  • 2007–2013
    • National Institute of Health Dr. Ricardo Jorge
      • Department of Environmental Health
      Oporto, Porto, Portugal