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Sousa M, Oliveira IM, Correia L, Gomes IB, Sousa CA, Braga DFO, Simões M. Far-UV-C irradiation promotes synergistic bactericidal action against adhered cells of Escherichia coli and Staphylococcus epidermidis. Sci Total Environ 2024; 917:170352. [PMID: 38286293 DOI: 10.1016/j.scitotenv.2024.170352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/17/2024] [Accepted: 01/20/2024] [Indexed: 01/31/2024]
Abstract
The contamination of indoor areas is a global health problem that can cause the dispersion of infectious diseases. In that sense, it is urgent to find new strategies applying a lower concentration of the traditional chemicals used for cleaning and disinfection. Ultraviolet radiation (UV), in particular far-UV-C (200-225 nm), has emerged as a successful, powerful, easy-to-apply, and inexpensive approach for bacterial eradication that still requires scientific assessment. This study investigated new strategies for disinfection based on far-UV-C (222 nm) combined with chlorine and mechanical cleaning, providing an innovative solution using low doses. The bactericidal activity of far-UV-C (222 nm) was tested at an intensity of irradiation from 78.4 μW/cm2 to 597.7 μW/cm2 (for 1 min) against Escherichia coli and Staphylococcus epidermidis adhered on polystyrene microtiter plates. It was further tested in combination with mechanical cleaning (ultrasounds for 1 min) and free chlorine (0.1, 0.5, and 1 mg/L for 5 min). The triple combination consisting of mechanical cleaning + free chlorine (0.5 mg/L) + far-UV-C (54 mJ/cm2) was tested against cells adhered to materials found in hospital settings and other public spaces: polyvinyl chloride (PVC), stainless steel (SS), and polyetheretherketone (PEEK). Disinfection with far-UV-C (54 mJ/cm2) and free chlorine at 0.5 mg/L for 5 min allowed a total reduction of culturable E. coli cells and a logarithmic reduction of 2.98 ± 0.03 for S. epidermidis. The triple combination of far-UV-C, free chlorine, and mechanical cleaning resulted in a total reduction of culturable cells for both adhered bacteria. Bacterial adhesion to PVC, SS, and PEEK occurred at distinct extents and influenced the bactericidal activity of the triple combination, with logarithmic reductions of up to three. The overall results highlight that, based on culturability assessment, far-UV-C (54 mJ/cm2) with chlorine (0.5 mg/L; 5 min) and mechanical cleaning (1 min) as an efficient disinfection strategy using mild conditions. The combination of culturability and viability assessment of disinfection is recommended to detect regrowth events and increase the effectiveness in microbial growth control.
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Affiliation(s)
- M Sousa
- LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - I M Oliveira
- LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - L Correia
- SpinnerDynamics, Lda., Rua da Junta de Freguesia 194, 4540-322 Escariz, Arouca, Portugal
| | - I B Gomes
- LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - C A Sousa
- LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - D F O Braga
- SpinnerDynamics, Lda., Rua da Junta de Freguesia 194, 4540-322 Escariz, Arouca, Portugal
| | - M Simões
- LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal.
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Oliveira IM, Gomes IB, Plácido A, Simões LC, Eaton P, Simões M. The impact of potassium peroxymonosulphate and chlorinated cyanurates on biofilms of Stenotrophomonas maltophilia: effects on biofilm control, regrowth, and mechanical properties. Biofouling 2023; 39:691-705. [PMID: 37811587 DOI: 10.1080/08927014.2023.2254704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/27/2023] [Indexed: 10/10/2023]
Abstract
The activity of two chlorinated isocyanurates (NaDCC and TCCA) and peroxymonosulphate (OXONE) was evaluated against biofilms of Stenotrophomonas maltophilia, an emerging pathogen isolated from drinking water (DW), and for the prevention of biofilm regrowth. After disinfection of pre-formed 48 h-old biofilms, the culturability was reduced up to 7 log, with OXONE, TCCA, and NaDCC showing more efficiency than free chlorine against biofilms formed on stainless steel. The regrowth of biofilms previously exposed to OXONE was reduced by 5 and 4 log CFU cm-2 in comparison to the unexposed biofilms and biofilms exposed to free chlorine, respectively. Rheometry analysis showed that biofilms presented properties of viscoelastic solid materials, regardless of the treatment. OXONE reduced the cohesiveness of the biofilm, given the significant decrease in the complex shear modulus (G*). AFM analysis revealed that biofilms had a fractured appearance and smaller bacterial aggregates dispersed throughout the surface after OXONE exposure than the control sample. In general, OXONE has been demonstrated to be a promising disinfectant to control DW biofilms, with a higher activity than chlorine. The results also show the impact of the biofilm mechanical properties on the efficacy of the disinfectants in biofilm control.
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Affiliation(s)
- I M Oliveira
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - I B Gomes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - A Plácido
- REQUIMTE/LAQV - Associated Laboratory for Green Chemistry of the Network of Chemistry and Technology, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal
| | - L C Simões
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal
- LABBELS - Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, Braga/Guimarães, Portugal
| | - P Eaton
- REQUIMTE/LAQV - Associated Laboratory for Green Chemistry of the Network of Chemistry and Technology, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal
- The Bridge, School of Chemistry, University of Lincoln, Lincoln, UK
| | - M Simões
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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Simões M, Steudel A, Santos APR. Liquid Water: A Single Approach to Its Two Continuous Phase Transitions. J Phys Chem B 2023; 127:955-960. [PMID: 36688909 DOI: 10.1021/acs.jpcb.2c07213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In this paper, we show that both continuous phase transitions of liquid water, the liquid-gas and the liquid-liquid, can be articulated within a single thermodynamic analytical formalism. This result follows from a combination of the two-liquid model (TLM), recently confirmed for water, with the idea of a thermal-dependent excluded volume, ve, concept introduced by van der Waals, in his famous state equation. Starting from the fundamentals of thermodynamics, it will be shown that the TLM naturally leads to the idea of an extensive thermal-dependent ve that acts as a parameter of the sample thermodynamic potentials. This procedure effectively separates the thermodynamics of the system into two parts: the first concerns the clusters' thermodynamics, taken as wandering particles, and the second concerns the thermal behavior of its internal structure (geometry and number of particles). From this result, we demonstrate that the condition of mechanical instability leads to not one but two critical points, each happening in one of the above-described parts of the system.
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Affiliation(s)
- M Simões
- Departamento de Física, Universidade Estadual de Londrina, Campus Universitário, 86051-990Londrina, PR, Brazil
| | - A Steudel
- Departamento de Física, Universidade Estadual de Londrina, Campus Universitário, 86051-990Londrina, PR, Brazil
| | - A P R Santos
- Departamento de Física, Universidade Estadual de Londrina, Campus Universitário, 86051-990Londrina, PR, Brazil
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Simões M, Steudel A, Yamaguti K, Cobo R, Santos A, Amaral R. An analytical approach to the anomalous specific heat of water. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.121049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Ribeiro M, Gomes IB, Saavedra MJ, Simões M. Photodynamic therapy and combinatory treatments for the control of biofilm-associated infections. Lett Appl Microbiol 2022; 75:548-564. [PMID: 35689422 DOI: 10.1111/lam.13762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 04/26/2022] [Accepted: 05/26/2022] [Indexed: 12/20/2022]
Abstract
The advent of antimicrobial resistance has added considerable impact to infectious diseases both in the number of infections and healthcare costs. Furthermore, the relentless emergence of multidrug-resistant bacteria, particularly in the biofilm state, has made mandatory the discovery of new alternative antimicrobial therapies that are capable to eradicate resistant bacteria and impair the development of new forms of resistance. Amongst the therapeutic strategies for treating biofilms, antimicrobial photodynamic therapy (aPDT) has shown great potential in inactivating several clinically relevant micro-organisms, including antibiotic-resistant 'priority bacteria' declared by the WHO as critical pathogens. Its antimicrobial effect is centred on the basis that harmless low-intensity light stimulates a non-toxic dye named photosensitizer, triggering the production of reactive oxygen species upon photostimulation. In addition, combination therapies of aPDT with other antimicrobial agents (e.g. antibiotics) have also drawn considerable attention, as it is a multi-target strategy. Therefore, the present review highlights the recent advances of aPDT against biofilms, also covering progress on combination therapy.
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Affiliation(s)
- M Ribeiro
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal.,ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal.,CIQUP/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal
| | - I B Gomes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal.,ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - M J Saavedra
- Department of Veterinary Sciences, School of Agriculture and Veterinary Science, UTAD, Vila Real, Portugal.,Centre for the Research and Technology for Agro-Environment and Biological Sciences (CITAB), UTAD, Vila Real, Portugal
| | - M Simões
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal.,ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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Ferro B, Simões M, Sucena M, Geraldes F, Águas F. 096 Precocious puberty in girls: A multidisciplinary view. Eur J Obstet Gynecol Reprod Biol 2022. [DOI: 10.1016/j.ejogrb.2022.02.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sucena M, Ferro B, David D, Simões M, Geraldes F, Águas F. 132 Turner syndrome and puberty. Eur J Obstet Gynecol Reprod Biol 2022. [DOI: 10.1016/j.ejogrb.2022.02.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Braga W, Santos O, Kimura N, Simões M, Palangana A. Optical signals of uniaxial and biaxial cholesteric lyotropic phases. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Afonso AC, Sousa M, Simões LC, Simões M. Phytochemicals Against Drug-Resistant Bacterial Biofilms and Use of Green Extraction Solvents to Increase Their Bioactivity. Advances in Experimental Medicine and Biology 2022. [DOI: 10.1007/5584_2022_723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Simões LC, Gomes IB, Sousa H, Borges A, Simões M. Biofilm formation under high shear stress increases resilience to chemical and mechanical challenges. Biofouling 2022; 38:1-12. [PMID: 34818957 DOI: 10.1080/08927014.2021.2006189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
The effect that the hydrodynamic conditions under which biofilms are formed has on their persistence is still unknown. This study assessed the behaviour of Pseudomonas fluorescens biofilms, formed on stainless steel under different shear stress (τw) conditions (1, 2 and 4 Pa), to chemical (benzalkonium chloride - BAC, glutaraldehyde - GLUT and sodium hypochlorite - SHC) and mechanical (20 Pa) treatments (alone and combined). The biofilms formed under different τw showed different structural characteristics. Those formed under a higher τw were invariably more tolerant to chemical and mechanical stresses. SHC was the biocide which caused the highest biofilm killing and removal, followed by BAC. The sequential exposure to biocides and mechanical stress was found to be insufficient for effective biofilm control. A basal layer containing biofilm cells mostly in a viable state remained on the surface of the cylinders, particularly for the 2 and 4 Pa-generated biofilms.
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Affiliation(s)
- L C Simões
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - H Sousa
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - A Borges
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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Paço M, Rodrigues A, Oliveira C, Carvalho D, Ferreira J, Simões M, Araújo FA, Chaves P. Cross-cultural adaptation and validation of the VISA-A questionnaire for Portuguese-speaking (Portugal) patients with Achilles tendinopathy. Eur J Public Health 2020. [DOI: 10.1093/eurpub/ckaa040.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Introduction Achilles tendinopathy is considered one of the most frequent injuries in individuals who practice regular physical activity, thus the existence of an instrument that allows the evaluation of the degree of severity of the lesion is important. The VISA-A was developed for English-speaking population to evaluate patients with this condition, and there is a need to adapt this tool to Portuguese (Portugal).
Objectives To cross-cultural adapt and validate the VISA-A questionnaire for Portuguese-speaking (Portugal) Achilles tendinopathy patients.
Methodology The VISA-A questionnaire was translated and cross-culturally adapted into Portuguese (VISA-A-Por) according to specific guidelines, using six steps: Translation, synthesis, back translation, expert committee review, pretesting (n = 10), and appraisal of the adaptation process. The resulting VISA-A-Por was then subjected to an analysis of the psychometric properties (construct validity, reproducibility [agreement and reliability], internal consistency and floor and ceiling effects) in 57 Achilles tendinopathy patients and 58 asymptomatic people. Participants completed the questionnaire at baseline and after a minimum interval of 48 hours.
Results The Visa-A-Por semantic and content validity was considered good by the expert committee and has construct validity shown by the differences between groups (p < 0,001). The questionnaire presented good internal consistency, with a Cronbach α of 0,88. Concerning reproducibility, agreement levels were considered optimal which can be verified in the Bland Altman graph, the standard error measurement (6,49) and the minimally important change (17,99 points), as well as the excellent ICC value (0,88). No ceiling-floor effect was found.
Conclusion The VISA-A-Por questionnaire has been shown to be equivalent to the original questionnaire, which indicates that it is a valid and reliable measure for the evaluation of the severity and functional impact of patellar tendinopathy in Portuguese-speaking (Portugal) patients.
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Affiliation(s)
- M Paço
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra - Paredes, Portugal
| | - A Rodrigues
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra - Paredes, Portugal
| | - C Oliveira
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra - Paredes, Portugal
| | - D Carvalho
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra - Paredes, Portugal
| | - J Ferreira
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra - Paredes, Portugal
| | - M Simões
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra - Paredes, Portugal
| | - FA Araújo
- ISPUP-EPIUnit, University of Porto, Porto, Portugal
| | - P Chaves
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra - Paredes, Portugal
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Arcolezi G, Luders D, Sampaio A, Simões M, Braga W, Santos O, Palangana A, Kimura N. Computational method to determine the pitch length in cholesteric liquid crystals. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.111752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gomes IB, Simões LC, Simões M. Influence of surface copper content on Stenotrophomonas maltophilia biofilm control using chlorine and mechanical stress. Biofouling 2020; 36:1-13. [PMID: 31997661 DOI: 10.1080/08927014.2019.1708334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 12/18/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
This work aimed to evaluate the action of materials with different copper content (0, 57, 96 and 100%) on biofilm formation and control by chlorination and mechanical stress. Stenotrophomonas maltophilia isolated from drinking water was used as a model microorganism and biofilms were developed in a rotating cylinder reactor using realism-based shear stress conditions. Biofilms were characterized phenotypically and exposed to three control strategies: 10 mg l-1 of free chlorine for 10 min, an increased shear stress (a fluid velocity of 1.5 m s-1 for 30s), and a combination of both treatments. These shock treatments were not effective in biofilm control. The benefits from the use of copper surfaces was found essentially in reducing the numbers of non-damaged cells. Copper materials demonstrated better performance in biofilm prevention than chlorine. In general, copper alloys may have a positive public health impact by reducing the number of non-damaged cells in the water delivered after chlorine exposure.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - L C Simões
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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Gomes IB, Querido MM, Teixeira JP, Pereira CC, Simões LC, Simões M. Prolonged exposure of Stenotrophomonas maltophilia biofilms to trace levels of clofibric acid alters antimicrobial tolerance and virulence. Chemosphere 2019; 235:327-335. [PMID: 31265978 DOI: 10.1016/j.chemosphere.2019.06.184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/13/2019] [Accepted: 06/24/2019] [Indexed: 06/09/2023]
Abstract
The presence of pharmaceuticals in water sources, including in drinking water (DW), is increasingly being recognized as an emerging and global concern for the environment and public health. Based on the principles of the "One Health" initiative, the present work aims to understand the effects of clofibric acid (CA), a lipid regulator, on the behavior of a selected bacterium isolated from drinking water (DW). Biofilms of the opportunistic pathogen Stenotrophomonas maltophilia were exposed to CA for 12 weeks at 170 and 17000 ng/L. The effects of CA were evaluated on planktonic S. maltophilia susceptibility to chlorine and antibiotics (amoxicillin, ciprofloxacin, erythromycin, kanamycin, levofloxacin, oxacillin, spectinomycin, tetracycline and trimethoprim-sulfamethoxazole), biofilm formation, motility, siderophores production and on the adhesion and internalization of the human colon adenocarcinoma cell line (HT-29). It was found that CA did not affect planktonic S. maltophilia tolerance to chlorine exposure. Additionally, no effects were observed on biofilm formation, motility and siderophores production. However, biofilms formed after CA exposure were more tolerant to chlorine disinfection and lower CFU reductions were obtained. Of additional concern was the effect of CA exposure on S. maltophilia increased tolerance to erythromycin. CA exposure also slightly reduced S. maltophilia ability to invade HT-29 cells. In conclusion, this work reinforces the importance of studying the effects of non-antibiotic contaminants on the behavior of environmental microorganisms, particularly their role as drivers affecting resistance evolution and selection.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal
| | - M M Querido
- Department of Environmental Health, Portuguese National Institute of Health DR. Ricardo Jorge, Rua Alexandre Herculano, 321, 4000-055, Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600, Porto, Portugal
| | - J P Teixeira
- Department of Environmental Health, Portuguese National Institute of Health DR. Ricardo Jorge, Rua Alexandre Herculano, 321, 4000-055, Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600, Porto, Portugal
| | - C C Pereira
- Department of Environmental Health, Portuguese National Institute of Health DR. Ricardo Jorge, Rua Alexandre Herculano, 321, 4000-055, Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600, Porto, Portugal
| | - L C Simões
- CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal.
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Simões M, Bertolino W, Davincy T. Curvature of the elastic deformations in a nematic sample. Eur Phys J E Soft Matter 2019; 42:59. [PMID: 31089899 DOI: 10.1140/epje/i2019-11817-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
In this work we study the geometry of the elastic deformations of the uniaxial nematic liquid crystals at the bulk. We will show that, at this region of the sample, the elastic terms of the free energy can be separated as the sum of two kinds of elastic deformations, the first is proportional to the Gaussian curvature obtained from the director field of a three-dimensional nematic sample and the second is composed by those terms that cannot be expressed as resulting from this curvature. To achieve these results we will construct the metric of an unixial nematic sample using the fact that the director gives the direction of the anisotropy of the system. With this approach we will give analytical and geometrical arguments to show that the elastic terms determined by [Formula: see text], [Formula: see text] and [Formula: see text] are contained in a curvature term, while the terms fixed by the splay elastic term, [Formula: see text], and the bend elastic term, [Formula: see text], are not. The novelty here is that while [Formula: see text] and [Formula: see text] do not contribute the bulk elastic energy of a nematic sample, they have an important contribution to the curvature of the system.
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Affiliation(s)
- M Simões
- Universidade Estadual de Londrina, Departamento de Fısica, Campus Universitário, 86051-990, Londrina (PR), Brazil.
| | - W Bertolino
- Universidade Estadual de Londrina, Departamento de Fısica, Campus Universitário, 86051-990, Londrina (PR), Brazil
| | - T Davincy
- Universidade Estadual de Londrina, Departamento de Fısica, Campus Universitário, 86051-990, Londrina (PR), Brazil
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Vale J, Ribeiro M, Abreu AC, Soares-Silva I, Simões M. The use of selected phytochemicals with EDTA against Escherichia coli and Staphylococcus epidermidis single- and dual-species biofilms. Lett Appl Microbiol 2019; 68:313-320. [PMID: 30790318 DOI: 10.1111/lam.13137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/30/2018] [Accepted: 12/02/2018] [Indexed: 12/20/2022]
Abstract
The aim of this study was the development of a novel and effective antibacterial formulation combining selected phytochemical compounds (quercetin, cuminaldehyde, indole-3-carbinol and vanillic acid) with ethylenediaminetetraacetic acid (EDTA), an aminopolycarboxylic acid. The antibacterial activity of the combinations was evaluated against Escherichia coli and Staphylococcus epidermidis in planktonic and sessile states as single and dual species. The compounds when applied individually demonstrated modest antibacterial activity. Nevertheless, synergy was observed when EDTA was combined with the selected phytochemicals, particularly with cuminaldehyde and indole-3-carbinol. These combinations were evaluated against single- and dual-species biofilms. An inactivation of 100% was obtained for almost all the biofilms, with E. coli biofilms showing the highest resistance. This study allowed the discovery of novel formulations of phytochemical compounds with antibacterial activity against E. coli and S. epidermidis single- and dual-species biofilms at concentrations close to the minimum bactericidal concentration. SIGNIFICANCE AND IMPACT OF THE STUDY: The synergistic combinations of EDTA and cuminaldehyde or indole-3-carbinol were effective against single- and dual-species E. coli and S. epidermidis planktonic cells and biofilms. The overall results highlight the role of phytochemical products as a green and sustainable source of antimicrobial potentiators to control bacteria in both planktonic and sessile states.
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Affiliation(s)
- J Vale
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - M Ribeiro
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - A C Abreu
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - I Soares-Silva
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen, Porto, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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17
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Vilas Boas J, Oliveira VB, Marcon LRC, Simões M, Pinto AMFR. Optimization of a single chamber microbial fuel cell using Lactobacillus pentosus: Influence of design and operating parameters. Sci Total Environ 2019; 648:263-270. [PMID: 30118939 DOI: 10.1016/j.scitotenv.2018.08.061] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/20/2018] [Accepted: 08/04/2018] [Indexed: 06/08/2023]
Abstract
Microbial fuel cells (MFCs) have been receiving an increased attention over the last years due to their potential to combat two global problems: waste pollution and energy demand. Additionally, when a wastewater is used, MFCs can perform its treatment while recovering energy, leading to the possibility of energy-producing wastewater treatment plants, offsetting their operational costs. However, to overcome their current limitations (lower power outputs and higher costs), a clear understanding of the effect of operation and design parameters on its overall performance is mandatory. Therefore, the goal of this work was to evaluate the effect of operating conditions - batch cycle and yeast extract concentration, and design parameters - anode electrode area, membrane thickness and active area, on the overall performance of a single chamber MFC. The MFC operated with a pure culture of Lactobacillus pentosus and a synthetic wastewater based on a real dairy industry effluent. The overall performance was evaluated through the power output and the COD removal rate. Additionally, the biofilm formed at the anode electrode was characterized in terms of biomass, proteins and polysaccharides content. For the conditions used in this work, a maximum power density of 5.04 ± 0.39 mW/m2 was achieved with an anode electrode area of 61 cm2, a batch cycle of 48 h, 50 mg/L of yeast extract and a Nafion 212 membrane with an active area of 25 cm2. The different conditions tested had a clear effect on the MFC energy production and biofilm characteristics, but not on the ability of L. pentosus to treat the dairy wastewater. The COD removal rates were in the range between 42% and 58%, for all the conditions tested.
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Affiliation(s)
- J Vilas Boas
- CEFT, Departamento de Eng. Química, Universidade do Porto, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - V B Oliveira
- CEFT, Departamento de Eng. Química, Universidade do Porto, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - L R C Marcon
- UNISEP-FEFB, União de Ensino do Sudoeste do Paraná, Faculdade Educacional de Francisco Beltrão, Av. União da Vitória, 14 Bairro Miniguaçu, 85605-040 Francisco Beltrão, Brazil
| | - M Simões
- LEPABE, Departamento de Eng. Química, Universidade do Porto, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - A M F R Pinto
- CEFT, Departamento de Eng. Química, Universidade do Porto, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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Apóstolo J, Couto F, Bobrowicz-Campos E, Dixe MA, Ribeiro J, Braúna M, Camacho T, Santos-Rocha R, Parreira P, Cruz A, Malça C, Dantas C, Jegundo L, Marcelino L, Simões M, Almeida M. An Interregional, Transdisciplinary and Good Practice-Based Approach for Frailty: the Mind&Gait Project. Transl Med UniSa 2019; 19:11-16. [PMID: 31360662 PMCID: PMC6581490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Social facilities such residential structures and day-centres increasingly seek integrated, structured, adapted, creative, dynamic and economic strategies to prevent frailty. The arising need of an aged and frail population requires innovative interventions and products to prevent cognitive and physical decline. The interregional MIND&GAIT project aims to promote independent living in frail older adults by improving cognition and gait ability by using assistive products. This transdisciplinary strategy within a 24-months period expects as project' deliverables: i) a structured and good practice-based combined intervention (CI) consisting of a cognitive stimulation programme and a physical exercise programme; ii) an auto-blocking mechanism for rolling walkers with biofeedback acquisition (ABMRW); iii) a randomized clinical trial to assess CI' effectiveness; and iv) a web-platform to be used as a repository that will support and disseminate the intervention materials, covering the action-line of translational research. Positive benefits are expected in prevention and maintenance of frail older adults' capacities. Preliminary results showed positive effects on the improvement of cognitive and physical functions, functionality and depressive symptomatology. The interregional geographical coverage induced by MIND&GAIT underlines the potential replicability of the project extension to the community in the Centro and Alentejo regions of Portugal. MIND&GAIT network supports actions and provides learning opportunities and emergence of locally-embedded support systems towards social innovation for older adults.
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Affiliation(s)
- J Apóstolo
- Nursing School of Coimbra,The Health Sciences Research Unit: Nursing, Nursing School of Coimbra
| | - F Couto
- The Health Sciences Research Unit: Nursing, Nursing School of Coimbra
| | | | - MA Dixe
- Centre for Innovative Care and Health Technology, Polytechnic Institute of Leiria
| | - J Ribeiro
- Centre for Innovative Care and Health Technology, Polytechnic Institute of Leiria
| | - M Braúna
- Centre for Innovative Care and Health Technology, Polytechnic Institute of Leiria
| | - T Camacho
- Centre for Innovative Care and Health Technology, Polytechnic Institute of Leiria
| | - R Santos-Rocha
- Sport Sciences School of Rio Maior, Polytechnic Institute of Santarém,Interdisciplinary Centre for the Study of Human Performance, Faculty of Human Kinetics, University of Lisbon
| | - P Parreira
- Nursing School of Coimbra,The Health Sciences Research Unit: Nursing, Nursing School of Coimbra
| | - A Cruz
- Nursing School of Coimbra,The Health Sciences Research Unit: Nursing, Nursing School of Coimbra
| | - C Malça
- Mechanical Engineering Department, Polytechnic Institute of Coimbra
| | | | | | - L Marcelino
- Informatics Engineering Department, School of Technology and Management, Polytechnic Institute of Leiria
| | - M Simões
- Santa Casa da Misericórdia de Alcobaça
| | - M Almeida
- Nursing School of Coimbra,The Health Sciences Research Unit: Nursing, Nursing School of Coimbra
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19
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Gomes IB, Simões LC, Simões M. The role of surface copper content on biofilm formation by drinking water bacteria. RSC Adv 2019; 9:32184-32196. [PMID: 35530774 PMCID: PMC9072912 DOI: 10.1039/c9ra05880j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/03/2019] [Indexed: 11/21/2022] Open
Abstract
Copper alloys demonstrated comparable or higher performance than elemental copper in biofilm control. The alloy containing 96% copper was the most promising surface in biofilm control and regrowth prevention.
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Affiliation(s)
- I. B. Gomes
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering
- University of Porto
- 4200-465 Porto
| | - L. C. Simões
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering
- University of Porto
- 4200-465 Porto
| | - M. Simões
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering
- University of Porto
- 4200-465 Porto
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20
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Gomes IB, Lemos M, Mathieu L, Simões M, Simões LC. The action of chemical and mechanical stresses on single and dual species biofilm removal of drinking water bacteria. Sci Total Environ 2018; 631-632:987-993. [PMID: 29728008 DOI: 10.1016/j.scitotenv.2018.03.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/29/2018] [Accepted: 03/05/2018] [Indexed: 06/08/2023]
Abstract
The presence of biofilms in drinking water distribution systems (DWDS) is a global public health concern as they can harbor pathogenic microorganisms. Sodium hypochlorite (NaOCl) is the most commonly used disinfectant for microbial growth control in DWDS. However, its effect on biofilm removal is still unclear. This work aims to evaluate the effects of the combination of chemical (NaOCl) and mechanical stresses on the removal of single and dual species biofilms of two bacteria isolated from DWDS and considered opportunistic, Acinectobacter calcoaceticus and Stenotrophomonas maltophilia. A rotating cylinder reactor was successfully used for the first time in drinking water biofilm studies with polyvinyl chloride as substratum. The single and dual species biofilms presented different characteristics in terms of metabolic activity, mass, density, thickness and content of proteins and polysaccharides. Their complete removal was not achieved even when a high NaOCl concentrations and an increasing series of shear stresses (from 2 to 23Pa) were applied. In general, NaOCl pre-treatment did not improve the impact of mechanical stress on biofilm removal. Dual species biofilms were colonized mostly by S. maltophilia and were more susceptible to chemical and mechanical stresses than these single species. The most efficient treatment (93% biofilm removal) was the combination of NaOCl at 175mg·l-1 with mechanical stress against dual species biofilms. Of concern was the high tolerance of S. maltophilia to chemical and mechanical stresses in both single and dual species biofilms. The overall results demonstrate the inefficacy of NaOCl on biofilm removal even when combined with high shear stresses.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - M Lemos
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - L Mathieu
- EPHE, Laboratory of Physical Chemistry and Microbiology for the Environment, UMR 7564 CNRS-Université de Lorraine, Nancy, France
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - L C Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal; CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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21
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Borges A, Lopez-Romero JC, Oliveira D, Giaouris E, Simões M. Prevention, removal and inactivation of Escherichia coli and Staphylococcus aureus biofilms using selected monoterpenes of essential oils. J Appl Microbiol 2017; 123:104-115. [PMID: 28497526 DOI: 10.1111/jam.13490] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/27/2017] [Accepted: 05/06/2017] [Indexed: 02/04/2023]
Abstract
AIMS The aim of this study was to investigate the antibiofilm potential of five essential oil (EO) components with cyclic (sabinene-SAB, carveol-C1, carvone-C2) and acyclic (citronellol-C3 and citronellal-C4) structures against Escherichia coli and Staphylococcus aureus. METHODS AND RESULTS The selected EO components prevented biofilm set-up, with C3 and C4 causing remarkable effects. When applied against pre-established biofilms, they promoted high biomass removal and inactivation of biofilm cells. Moreover, no viable E. coli biofilm cells were detected after exposure to SAB at 5 × MIC and 10 × MIC, and a significant viability decrease was observed for both bacteria with the other EO components. SAB, C3 and C4 caused the most prominent effects apparently due to their octanol-water partition coefficient (Po/w), the number of rotatable bonds (n-ROTB) and the free hydroxyl groups. CONCLUSIONS The overall results demonstrated that the selected EO components, particularly SAB, C3 and C4 are of interest as new lead molecules to both prevent biofilm set-up and to control pre-established biofilms of E. coli and S. aureus. SIGNIFICANCE AND IMPACT OF THE STUDY The tested EO components exhibited prominent antibiofilm properties against E. coli and S. aureus providing a novel and effective alternative/complementary approach to counteract chronic infections and the transmission of diseases in clinical settings.
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Affiliation(s)
- A Borges
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - J C Lopez-Romero
- CIAD, Research Center for Food and Development, Hermosillo, Sonora, Mexico
| | - D Oliveira
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - E Giaouris
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, Myrina, Lemnos Island, Greece
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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22
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Amaral L, Martins A, Alves J, Fernandes F, Fregni F, Simis M, Almeida J, Simões M. Memory enhancement in aging - the role of cognitive training combined with tDCS: Preliminary results. Brain Stimul 2017. [DOI: 10.1016/j.brs.2017.01.216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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23
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Malheiro J, Gomes I, Borges A, Bastos MMSM, Maillard JY, Borges F, Simões M. Phytochemical profiling as a solution to palliate disinfectant limitations. Biofouling 2016; 32:1007-1016. [PMID: 27552663 DOI: 10.1080/08927014.2016.1220550] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/30/2016] [Indexed: 06/06/2023]
Abstract
The indiscriminate use of biocides for general disinfection has contributed to the increased incidence of antimicrobial tolerant microorganisms. This study aims to assess the potential of seven phytochemicals (tyrosol, caffeic acid, ferulic acid, cinnamaldehyde, coumaric acid, cinnamic acid and eugenol) in the control of planktonic and sessile cells of Staphylococcus aureus and Escherichia coli. Cinnamaldehyde and eugenol showed antimicrobial properties, minimum inhibitory concentrations of 3-5 and 5-12 mM and minimum bactericidal concentrations of 10-12 and 10-14 mM against S. aureus and E. coli, respectively. Cinnamic acid was able to completely control adhered bacteria with effects comparable to peracetic acid and sodium hypochlorite and it was more effective than hydrogen peroxide (all at 10 mM). This phytochemical caused significant changes in bacterial membrane hydrophilicity. The observed effectiveness of phytochemicals makes them interesting alternatives and/or complementary products to commonly used biocidal products. Cinnamic acid is of particular interest for the control of sessile cells.
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Affiliation(s)
- J Malheiro
- a LEPABE, Department of Chemical Engineering, Faculty of Engineering of University of Porto , Porto , Portugal
- b CIQUP, Department of Chemistry and Biochemistry, Faculty of Sciences University of Porto , Porto , Portugal
- c Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University , Cardiff , UK
| | - I Gomes
- a LEPABE, Department of Chemical Engineering, Faculty of Engineering of University of Porto , Porto , Portugal
| | - A Borges
- a LEPABE, Department of Chemical Engineering, Faculty of Engineering of University of Porto , Porto , Portugal
- b CIQUP, Department of Chemistry and Biochemistry, Faculty of Sciences University of Porto , Porto , Portugal
| | - M M S M Bastos
- a LEPABE, Department of Chemical Engineering, Faculty of Engineering of University of Porto , Porto , Portugal
| | - J-Y Maillard
- c Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University , Cardiff , UK
| | - F Borges
- b CIQUP, Department of Chemistry and Biochemistry, Faculty of Sciences University of Porto , Porto , Portugal
| | - M Simões
- a LEPABE, Department of Chemical Engineering, Faculty of Engineering of University of Porto , Porto , Portugal
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Gomes IB, Simões M, Simões LC. The effects of sodium hypochlorite against selected drinking water-isolated bacteria in planktonic and sessile states. Sci Total Environ 2016; 565:40-48. [PMID: 27156214 DOI: 10.1016/j.scitotenv.2016.04.136] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/16/2016] [Accepted: 04/17/2016] [Indexed: 06/05/2023]
Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
| | - L C Simões
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Braga W, Santos O, Luders D, Kimura N, Sampaio A, Simões M, Palangana A. Corrigendum to “Refractive index measurements in uniaxial and biaxial lyotropic nematic phases” [J. Mol. Liq. 213 (2016) 186–190]. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Moreira J, Fulgêncio R, Alves P, Machado I, Bialuch I, Melo L, Simões M, Mergulhão F. Evaluation of SICAN performance for biofouling mitigation in the food industry. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.10.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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27
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Moreira J, Fulgêncio R, Oliveira F, Machado I, Bialuch I, Melo L, Simões M, Mergulhão F. Evaluation of SICON ® surfaces for biofouling mitigation in critical process areas. Food and Bioproducts Processing 2016. [DOI: 10.1016/j.fbp.2016.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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28
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Gomes IB, Malheiro J, Mergulhão F, Maillard JY, Simões M. Comparison of the efficacy of natural-based and synthetic biocides to disinfect silicone and stainless steel surfaces. Pathog Dis 2016; 74:ftw014. [PMID: 26926153 DOI: 10.1093/femspd/ftw014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2016] [Indexed: 01/22/2023] Open
Abstract
New biocidal solutions are needed to combat effectively the evolution of microbes developing antibiotic resistance while having a low or no environmental toxicity impact. This work aims to assess the efficacy of commonly used biocides and natural-based compounds on the disinfection of silicone and stainless steel (SS) surfaces seeded with differentStaphylococcus aureusstrains. Minimum inhibitory concentration was determined for synthetic (benzalkonium chloride-BAC, glutaraldehyde-GTA,ortho-phthalaldehyde-OPA and peracetic acid-PAA) and natural-based (cuminaldehyde-CUM), eugenol-EUG and indole-3-carbinol-I3C) biocides by the microdilution method. The efficacy of selected biocides at MIC, 10 × MIC and 5500 mg/L (representative in-use concentration) on the disinfection of sessileS. aureuson silicone and SS was assessed by viable counting. Silicone surfaces were harder to disinfect than SS. GTA, OPA and PAA yielded complete CFU reduction of sessile cells for all test concentrations as well as BAC at 10 × MIC and 5500 mg/L. CUM was the least efficient compound. EUG was efficient for SS disinfection, regardless of strains and concentrations tested. I3C at 10 × MIC and 5500 mg/L was able to cause total CFU reduction of silicone and SS deposited bacteria. Although not so efficient as synthetic compounds, the natural-based biocides are promising to be used in disinfectant formulations, particularly I3C and EUG.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - J Malheiro
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - F Mergulhão
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - J-Y Maillard
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, Wales CF10 3NB, UK
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
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29
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Lemos M, Wang S, Ali A, Simões M, Wilson D. A fluid dynamic gauging device for measuring biofilm thickness on cylindrical surfaces. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2015.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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Gonçalves AL, Abreu AC, Coqueiro A, Gaspar A, Borges F, Choi YH, Pires JCM, Simões M. Co-cultivation of Synechocystis salina and Pseudokirchneriella subcapitata under varying phosphorus concentrations evidences an allelopathic competition scenario. RSC Adv 2016. [DOI: 10.1039/c6ra07771d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This study suggests growth inhibition ofSynechocystis salinawhen co-cultured withPseudokirchneriella subcapitatathrough the production of an allelochemical – lactic acid.
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Affiliation(s)
- A. L. Gonçalves
- LEPABE
- Departamento de Engenharia Química
- Faculdade de Engenharia
- Universidade do Porto
- 4200-465 Porto
| | - A. C. Abreu
- LEPABE
- Departamento de Engenharia Química
- Faculdade de Engenharia
- Universidade do Porto
- 4200-465 Porto
| | - A. Coqueiro
- Natural Products Laboratory
- Institute of Biology
- Leiden University
- Leiden
- The Netherlands
| | - A. Gaspar
- CIQUP
- Department of Chemistry and Biochemistry
- Faculty of Sciences
- University of Porto
- Porto
| | - F. Borges
- CIQUP
- Department of Chemistry and Biochemistry
- Faculty of Sciences
- University of Porto
- Porto
| | - Y. H. Choi
- Natural Products Laboratory
- Institute of Biology
- Leiden University
- Leiden
- The Netherlands
| | - J. C. M. Pires
- LEPABE
- Departamento de Engenharia Química
- Faculdade de Engenharia
- Universidade do Porto
- 4200-465 Porto
| | - M. Simões
- LEPABE
- Departamento de Engenharia Química
- Faculdade de Engenharia
- Universidade do Porto
- 4200-465 Porto
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31
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Braga W, Santos O, Luders D, Kimura N, Sampaio A, Simões M, Palangana A. Refractive index measurements in uniaxial and biaxial lyotropic nematic phases. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2015.10.058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Abreu AC, Paulet D, Coqueiro A, Malheiro J, Borges A, Saavedra MJ, Choi YH, Simões M. Antibiotic adjuvants from Buxus sempervirens to promote effective treatment of drug-resistant Staphylococcus aureus biofilms. RSC Adv 2016. [DOI: 10.1039/c6ra21137b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Plants have been long scrutinized in the quest for new antibiotics, but no strong antibiotic molecule was ever found.
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Affiliation(s)
- A. C. Abreu
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering
- University of Porto
- 4200-465 Porto
| | - D. Paulet
- Natural Products Laboratory
- Institute of Biology
- Leiden University
- Leiden
- The Netherlands
| | - A. Coqueiro
- Natural Products Laboratory
- Institute of Biology
- Leiden University
- Leiden
- The Netherlands
| | - J. Malheiro
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering
- University of Porto
- 4200-465 Porto
| | - A. Borges
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering
- University of Porto
- 4200-465 Porto
| | - M. J. Saavedra
- CECAV
- Veterinary and Animal Science Research Center and Veterinary Science Department
- University of Trás-os-Montes and Alto Douro
- 5000-801 Vila Real
- Portugal
| | - Y. H. Choi
- Natural Products Laboratory
- Institute of Biology
- Leiden University
- Leiden
- The Netherlands
| | - M. Simões
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering
- University of Porto
- 4200-465 Porto
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Malheiro J, Araújo P, Machado I, Lemos M, Mergulhão F, Melo L, Simões M. The Effects of Selected Brominated and Chlorinated Chemicals onPseudomonas fluorescensPlanktonic Cells and Flow-Generated Biofilms. J FOOD PROCESS PRES 2015. [DOI: 10.1111/jfpp.12609] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- J. Malheiro
- LEPABE; Department of Chemical Engineering; Faculty of Engineering; University of Porto; Rua Dr. Roberto Frias s/n 4200-465 Porto Portugal
| | - P. Araújo
- LEPABE; Department of Chemical Engineering; Faculty of Engineering; University of Porto; Rua Dr. Roberto Frias s/n 4200-465 Porto Portugal
| | - I. Machado
- LEPABE; Department of Chemical Engineering; Faculty of Engineering; University of Porto; Rua Dr. Roberto Frias s/n 4200-465 Porto Portugal
| | - M. Lemos
- LEPABE; Department of Chemical Engineering; Faculty of Engineering; University of Porto; Rua Dr. Roberto Frias s/n 4200-465 Porto Portugal
- Department of Chemical Engineering & Biotechnology; New Museums Site; Cambridge UK
| | - F. Mergulhão
- LEPABE; Department of Chemical Engineering; Faculty of Engineering; University of Porto; Rua Dr. Roberto Frias s/n 4200-465 Porto Portugal
| | - L. Melo
- LEPABE; Department of Chemical Engineering; Faculty of Engineering; University of Porto; Rua Dr. Roberto Frias s/n 4200-465 Porto Portugal
| | - M. Simões
- LEPABE; Department of Chemical Engineering; Faculty of Engineering; University of Porto; Rua Dr. Roberto Frias s/n 4200-465 Porto Portugal
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Voos M, Martini J, Simões M, Hukuda M, Favero F, Oliveira A, Caromano F. The relevance of timed movements on functional assessment in Duchenne muscular dystrophy. Neuromuscul Disord 2015. [DOI: 10.1016/j.nmd.2015.06.165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Costa B, Martins P, Veríssimo C, Simões M, Tomé M, Marques G, Grazina M, Pimentel J, Castro-Sousa F. MON-PP279: Plasma Glutamine Concentration a Predictive Factor of Actuarial Survival in Critical Surgical Patients? Clin Nutr 2015. [DOI: 10.1016/s0261-5614(15)30711-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Costa B, Martins P, Veríssimo C, Simões M, Tomé M, Marques G, Grazina M, Pimentel J, Castro-Sousa F. SUN-PP042: Argininemia and Plasma Arginine Bioavailability - Predictive Factors of Mortality in the Severe Trauma Patient? Clin Nutr 2015. [DOI: 10.1016/s0261-5614(15)30193-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Moreira J, Gomes L, Simões M, Melo L, Mergulhão F. The impact of material properties, nutrient load and shear stress on biofouling in food industries. Food and Bioproducts Processing 2015. [DOI: 10.1016/j.fbp.2015.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Gomes IB, Simões M, Simões LC. An overview on the reactors to study drinking water biofilms. Water Res 2014; 62:63-87. [PMID: 24937357 DOI: 10.1016/j.watres.2014.05.039] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 06/03/2023]
Abstract
The development of biofilms in drinking water distribution systems (DWDS) can cause pipe degradation, changes in the water organoleptic properties but the main problem is related to the public health. Biofilms are the main responsible for the microbial presence in drinking water (DW) and can be reservoirs for pathogens. Therefore, the understanding of the mechanisms underlying biofilm formation and behavior is of utmost importance in order to create effective control strategies. As the study of biofilms in real DWDS is difficult, several devices have been developed. These devices allow biofilm formation under controlled conditions of physical (flow velocity, shear stress, temperature, type of pipe material, etc), chemical (type and amount of nutrients, type of disinfectant and residuals, organic and inorganic particles, ions, etc) and biological (composition of microbial community - type of microorganism and characteristics) parameters, ensuring that the operational conditions are similar as possible to the DWDS conditions in order to achieve results that can be applied to the real scenarios. The devices used in DW biofilm studies can be divided essentially in two groups, those usually applied in situ and the bench top laboratorial reactors. The selection of a device should be obviously in accordance with the aim of the study and its advantages and limitations should be evaluated to obtain reproducible results that can be transposed into the reality of the DWDS. The aim of this review is to provide an overview on the main reactors used in DW biofilm studies, describing their characteristics and applications, taking into account their main advantages and limitations.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - L C Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal; CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Santos O, Braga W, Luders D, Kimura N, Simões M, Palangana A. Study of optical conoscopy in uniaxial and biaxial nematic lyotropic phases. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2014.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gomes LC, Silva LN, Simões M, Melo LF, Mergulhão FJ. Escherichia coli adhesion, biofilm development and antibiotic susceptibility on biomedical materials. J Biomed Mater Res A 2014; 103:1414-23. [PMID: 25044887 DOI: 10.1002/jbm.a.35277] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/22/2014] [Accepted: 07/09/2014] [Indexed: 11/11/2022]
Abstract
The aim of this work was to test materials typically used in the construction of medical devices regarding their influence in the initial adhesion, biofilm development and antibiotic susceptibility of Escherichia coli biofilms. Adhesion and biofilm development was monitored in 12-well microtiter plates containing coupons of different biomedical materials--silicone (SIL), stainless steel (SS) and polyvinyl chloride (PVC)--and glass (GLA) as control. The susceptibility of biofilms to ciprofloxacin and ampicillin was assessed, and the antibiotic effect in cell morphology was observed by scanning electron microscopy. The surface hydrophobicity of the bacterial strain and materials was also evaluated from contact angle measurements. Surface hydrophobicity was related with initial E. coli adhesion and subsequent biofilm development. Hydrophobic materials, such as SIL, SS, and PVC, showed higher bacterial colonization than the hydrophilic GLA. Silicone was the surface with the greatest number of adhered cells and the biofilms formed on this material were also less susceptible to both antibiotics. It was found that different antibiotics induced different levels of elongation on E. coli sessile cells. Results revealed that, by affecting the initial adhesion, the surface properties of a given material can modulate biofilm buildup and interfere with the outcome of antimicrobial therapy. These findings raise the possibility of fine-tuning surface properties as a strategy to reach higher therapeutic efficacy.
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Affiliation(s)
- L C Gomes
- LEPABE - Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, Porto, Portugal
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Dias C, Serra CR, Simões LC, Simões M, Martinez-Murcia A, Saavedra MJ. Extended-spectrum β-lactamase and carbapenemase-producing Aeromonas species in wild animals from Portugal. Vet Rec 2014; 174:532. [PMID: 24728490 DOI: 10.1136/vr.101803] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- C Dias
- Veterinary and Animal Science Research Centre, Carla Dias, Centre for the Research and Technology for Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real 5000-801, Portugal
| | - C R Serra
- Veterinary and Animal Science Research Centre, Carla Dias, Centre for the Research and Technology for Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real 5000-801, Portugal
| | - L C Simões
- IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga 4710-057, Portugal LEPAE - Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto 4200-465, Portugal
| | - M Simões
- LEPAE - Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto 4200-465, Portugal
| | - A Martinez-Murcia
- Area de Microbiología, EPSO, Universidad Miguel Hernández, Orihuela E-03300, Alicante, Spain
| | - M J Saavedra
- Veterinary and Animal Science Research Centre, Carla Dias, Centre for the Research and Technology for Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real 5000-801, Portugal Department of Veterinary Sciences, School of Agriculture and Veterinary Science, University of Trás-os-Montes e Alto Douro, Vila Real 5000-801, Portugal
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Gomes LC, Moreira JMR, Teodósio JS, Araújo JDP, Miranda JM, Simões M, Melo LF, Mergulhão FJ. 96-well microtiter plates for biofouling simulation in biomedical settings. Biofouling 2014; 30:535-46. [PMID: 24684538 DOI: 10.1080/08927014.2014.890713] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Microtiter plates with 96 wells are routinely used in biofilm research mainly because they enable high-throughput assays. These platforms are used in a variety of conditions ranging from static to dynamic operation using different shaking frequencies and orbital diameters. The main goals of this work were to assess the influence of nutrient concentration and flow conditions on biofilm formation by Escherichia coli in microtiter plates and to define the operational conditions to be used in order to simulate relevant biomedical scenarios. Assays were performed in static mode and in incubators with distinct orbital diameters using different concentrations of glucose, peptone and yeast extract. Computational fluid dynamics (CFD) was used to simulate the flow inside the wells for shaking frequencies ranging from 50 to 200 rpm and orbital diameters from 25 to 100 mm. Higher glucose concentrations enhanced adhesion of E. coli in the first 24 h, but variation in peptone and yeast extract concentration had no significant impact on biofilm formation. Numerical simulations indicate that 96-well microtiter plates can be used to simulate a variety of biomedical scenarios if the operating conditions are carefully set.
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Affiliation(s)
- L C Gomes
- a LEPABE - Department of Chemical Engineering, Faculty of Engineering , University of Porto , Porto , Portugal
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Freire FMC, Kimura NM, Luders DD, Palangana AJ, Simões M. Calculation of the nematic entropy using digital images. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 88:064502. [PMID: 24483590 DOI: 10.1103/physreve.88.064502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Indexed: 06/03/2023]
Abstract
In this work we will use digital images to compute the entropy dependence on temperature of a nematic lyotropic sample. The set of images comprehend the entire temperature range between a reentrant nematic isotropic phase transition, at a low temperature, and a usual nematic isotropic phase transition at a higher temperature. We will show that, inside the nematic phase, the image entropy profile agrees accurately with the entropy given by the Maier-Saupe model. As far as we know, this is the first time that the entropy of a lyotropic nematic phase is evaluated by this method, which introduces a way to measure their macroscopic variables. Namely, being that the entropy is a thermodynamical potential, this result implies that digital images can be used to compute mean values of nematic random variables.
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Affiliation(s)
- F M C Freire
- Departamento de Física, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil
| | - N M Kimura
- Departamento de Física, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil
| | - D D Luders
- Departamento de Física, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil
| | - A J Palangana
- Departamento de Física, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil
| | - M Simões
- Departamento de Física, Universidade Estadual de Londrina, Campus Universitário, 86051-990 Londrina, PR, Brazil
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Braga W, Santos O, Luders D, Sampaio A, Kimura N, Simões M, Palangana A. Conoscopic image of a biaxial negative nematic phase in a potassium laurate–decanol–D2O mixture. J Mol Liq 2013. [DOI: 10.1016/j.molliq.2013.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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47
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Gomes LC, Moreira JMR, Miranda JM, Simões M, Melo LF, Mergulhão FJ. Macroscale versus microscale methods for physiological analysis of biofilms formed in 96-well microtiter plates. J Microbiol Methods 2013; 95:342-9. [PMID: 24140575 DOI: 10.1016/j.mimet.2013.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 10/01/2013] [Accepted: 10/08/2013] [Indexed: 12/24/2022]
Abstract
Microtiter plates with 96 wells have become one of the preferred platforms for biofilm studies mainly because they enable high-throughput assays. In this work, macroscale and microscale methods were used to study the impact of hydrodynamic conditions on the physiology and location of Escherichia coli JM109(DE3) biofilms formed in microtiter plates. Biofilms were formed in shaking and static conditions, and two macroscale parameters were assayed: the total amount of biofilm was measured by the crystal violet assay and the metabolic activity was determined by the resazurin assay. From the macroscale point of view, there were no statistically significant differences between the biofilms formed in static and shaking conditions. However, at a microscale level, the differences between both conditions were revealed using scanning electron microscopy (SEM). It was observed that biofilm morphology and spatial distribution along the wall were different in these conditions. Simulation of the hydrodynamic conditions inside the wells at a microscale was performed by computational fluid dynamics (CFD). These simulations showed that the shear strain rate was unevenly distributed on the walls during shaking conditions and that regions of higher shear strain rate were obtained closer to the air/liquid interface. Additionally, it was shown that wall regions subjected to higher shear strain rates were associated with the formation of biofilms containing cells of smaller size. Conversely, regions with lower shear strain rate were prone to have a more uniform spatial distribution of adhered cells of larger size. The results presented on this work highlight the wealth of information that may be gathered by complementing macroscale approaches with a microscale analysis of the experiments.
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Affiliation(s)
- L C Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, Porto, Portugal
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Simões M, Severo M, Oliveira A, Santos S, Lopes C. Effect of peripheral body fat on adipokines and C-reactive protein, taking into account different models of body fat prediction. Eur J Public Health 2013. [DOI: 10.1093/eurpub/ckt126.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Pires JCM, Alvim-Ferraz MCM, Martins FG, Simões M. Wastewater treatment to enhance the economic viability of microalgae culture. Environ Sci Pollut Res Int 2013; 20:5096-5105. [PMID: 23673923 DOI: 10.1007/s11356-013-1791-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/29/2013] [Indexed: 06/02/2023]
Abstract
Microalgae culture is still not economically viable and it presents some negative environmental impacts, concerning water, nutrient and energy requirements. In this context, this study aims to review the recent advances on microalgal cultures in wastewaters to enhance their economic viability. We focused on three different culture concepts: (1) suspended cell systems, (2) cell immobilization, and (3) microalgae consortia. Cultures with suspended cells are the most studied. The nutrient removal efficiencies are usually high for wastewaters of different sources. However, biomass harvesting is difficult and a costly process due to the small cell size and lower culture density. On the other hand, the cell immobilization systems showed to be the solution for this problem, having as main limitation the nutrient diffusion from bulk to cells, which results in a reduced nutrient removal efficiency. The consortium between microalgae and bacteria enhances the growth of both microorganisms. This culture concept showed to be a promising technology to improve wastewater treatment, regarding not only nutrient removal but also biomass harvesting by bioflocculation. The aggregation mechanism must be studied in depth to find the process parameters that would lead to an effective and cheap harvesting process.
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Affiliation(s)
- J C M Pires
- LEPAE, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
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