Página 1 dos resultados de 5172 itens digitais encontrados em 0.013 segundos

O papel do biofilme na rinossinusite crônica com polipose nasossinusal; The role of biofilms in chronic sinusitis with nasal polyps

Bezerra, Thiago Freire Pinto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/06/2012 PT
Relevância na Pesquisa
37.14%
Introdução: A patogenia da rinossinusite crônica com polipose nasossinusal não está completamente estabelecida e existem algumas explicações para essa doença como os superantigenos, o desequilíbrio inflamatório e, mais recentemente, o biofilme. Objetivos: Avaliar a associação entre a presença do biofilme e a presença de rinossinusite crônica com polipose nasossinusal. Avaliar o quadro clínico e radiológico pré-operatória e pós-operatória segundo a presença do biofilme. Métodos: Este é uma estudo realizado em um hospital terciário universitário. A primeira parte foi um estudo caso-controle com um grupo de 33 pacientes consecutivos com rinossinusite crônica com polipose nasossinusal submetidos a cirurgica endoscópica nasossinusal e um grupo controle de 27 pacientes submetidos a septoplastia para tratamento de obstrução nasal. As amostras da mucosa foram coletadas no intra-operatório para avaliação por microscopia eletrônica de varredura para determinar a presença do biofilme. A segunda parte foi um estudo prospectivo em que dados pré-operatórios e pós-operatórios foram registrados, incluindo avaliações padronizadas da qualidade de vida doença-específica relacionadas à obstrução nasal e à rinossinusite...

Silver colloidal nanoparticles: Effect on matrix composition and structure of Candida albicans and Candida glabrata biofilms

Monteiro, D. R.; Silva, S.; Negri, M.; Gorup, L. F.; de Camargo, E. R.; Oliveira, R.; Barbosa, D. B.; Henriques, M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1175-1183
ENG
Relevância na Pesquisa
37.08%
Aim: The aim of this study was to assess the effect of different silver nanoparticles (SN) concentrations on the matrix composition and structure of Candida albicans and Candida glabrata biofilms. Methods and Results: Candida biofilms were developed in 6-well microtiter plates during 48 h. After, these biofilms were exposed to 13·5 or 54 μg SN ml-1 for 24 h. Then, extracellular matrices were extracted from biofilms and analysed chemically in terms of proteins, carbohydrates and DNA. To investigate the biofilm structure, scanning electron microscopy (SEM) and epifluorescence microscopy were used. SN interfered with the matrix composition of Candida biofilms tested in terms of protein, carbohydrate and DNA, except for the protein content of C. albicans biofilm. By SEM, Candida biofilms treated with SN revealed structural differences, when compared with the control groups. Further, SN showed a trend of agglomeration within the biofilms. Epifluorescence microscopy images suggest that SN induced damage on cell walls of the Candida isolates tested. Conclusions: In general, irrespective of concentration, SN affected the matrix composition and structure of Candida biofilms and these findings may be related to the mechanisms of biocide action of SN. Significance and Impact of the Study: This study reveals new insights about the behaviour of SN when in contact with Candida biofilms. SN may contribute to the development of therapies to prevent or control Candida infections. © 2012 The Society for Applied Microbiology.

Development of Candida albicans biofilms in the presence of fluconazole : effects on extracellular matrix = Desenvolvimento de biofilmes de Candida albicans na presença de fluconazol : efeitos na matriz extracelular; Desenvolvimento de biofilmes de Candida albicans na presença de fluconazol : efeitos na matriz extracelular

Letícia Machado Gonçalves
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/09/2013 PT
Relevância na Pesquisa
37.15%
O fluconazol (FLZ) é um antifúngico amplamente utilizado no tratamento da candidose associada ao uso de prótese dental. No entanto, o sucesso desta terapia pode ser dificultado pela presença da matriz extracelular dos biofilmes de Candida albicans. Estudos já foram conduzidos avaliando o efeito do FLZ em biofilmes de C. albicans, no entanto, estudos que simulem uma condição na qual os biofilmes são desenvolvidos na presença do FLZ são escassos. Ainda, na tentativa de avaliar a organização tridimensional destes biofilmes, várias técnicas de microscopia já foram descritas, apesar de pouca atenção ser dada na análise da matriz extracelular. Frente ao exposto, o objetivo deste trabalho foi avaliar a matriz extracelular de biofilmes de C. albicans na presença de concentração salivar de FLZ. Dois estudos foram conduzidos e, em ambos, discos (10 mm x 2 mm) de resina acrílica à base de poli (metil metacrilato) foram confeccionados e cobertos com uma película de saliva sobre a qual biofilmes de C. albicans foram desenvolvidos. O primeiro estudo foi conduzido com o objetivo de definir uma metodologia para análise da matriz extracelular. Biofilmes de C. albicans ATCC 90028 foram desenvolvidos em meio de cultura sem suplementação (controle) ou suplementado com glicose ou sacarose...

The role of hydrodynamic stress on the phenotypic characteristics of single and binary biofilms of Pseudomonas fluorescens

Simões, M.; Pereira, Maria Olívia; Vieira, M. J.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2006 ENG
Relevância na Pesquisa
37.08%
This study investigates the phenotype of turbulent (Re = 5200) and laminar (Re = 2000) flow-generated P. fluorescens biofilms. Three P. fluorescens strains, the type strain– ATCC 13525 and two strains isolated from an industrial processing plant - D3-348 and D3-350, were used throughout this study. The isolated strains were used to form single and binary biofilms. The biofilm physiology (metabolic activity, cellular density, mass, extracellular polymeric substances, structural characteristics and outer membrane proteins-OMP expression) was compared. The results indicate that, for every situation, turbulent flow-generated biofilms were more active (P < 0.05), had more mass per cm2 (P < 0.05), a higher cellular density (P < 0.05), distinct morphology, similar matrix proteins (P > 0.1) and identical (isolated strains - single and binary biofilms) and higher (type strain) matrix polysaccharides contents (P < 0.05) than laminar flow-generated biofilms. Flow-generated biofilms formed by the type strain revealed a considerable higher cellular density and amount of matrix polysaccharides than single and binary biofilms formed by the isolated strains (P < 0.05). Similar OMP expression was detected for the several single strains and for the binary situation...

The role of hydrodynamic stress on the phenotypic characteristics of single and binary biofilms of Pseudomonas fluorescens

Simões, M.; Pereira, Maria Olívia; Vieira, M. J.
Fonte: IWA Publishing Publicador: IWA Publishing
Tipo: Artigo de Revista Científica
Publicado em //2007 ENG
Relevância na Pesquisa
37.08%
This study investigates the phenotype of turbulent (Re=5,200) and laminar (Re=2,000) flowgenerated Pseudomonas fluorescens biofilms. Three P. fluorescens strains, the type strain ATCC 13525 and two strains isolated from an industrial processing plant, D3-348 and D3-350, were used throughout this study. The isolated strains were used to form single and binary biofilms. The biofilm physiology (metabolic activity, cellular density, mass, extracellular polymeric substances, structural characteristics and outer membrane proteins [OMP] expression) was compared. The results indicate that, for every situation, turbulent flow-generated biofilms were more active ( p <0.05), had more mass per cm2 ( p<0.05), a higher cellular density ( p <0.05), distinct morphology, similar matrix proteins ( p>0.1) and identical (isolated strains – single and binary biofilms) and higher (type strain) matrix polysaccharides contents ( p<0.05) than laminar flow-generated biofilms. Flow-generated biofilms formed by the type strain revealed a considerably higher cellular density and amount of matrix polysaccharides than single and binary biofilms formed by the isolated strains ( p <0.05). Similar OMP expression was detected for the several single strains and for the binary situation...

The effects of glutaraldehyde on the control of single and dual biofilms of Bacillus cereus and Pseudomonas fluorescens

Simões, Lúcia C.; Lemos, Madalena; Araújo, Paula; Pereira, Ana M.; Simões, M.
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Publicado em //2011 ENG
Relevância na Pesquisa
37.16%
Glutaraldehyde (GLUT) was evaluated for control of single and dual species biofilms of Bacillus cereus and Pseudomonas fluorescens on stainless steel surfaces using a chemostat system. The biofilms were characterized in terms of mass, cell density, total and matrix proteins and polysaccharides. The control action of GLUT was assessed in terms of inactivation and removal of biofilm. Post-biocide action was characterized 3, 7, 12, 24, 48 and 72 h after treatment. Tests with planktonic cells were also performed for comparison. The results demonstrated that in dual species biofilms the metabolic activity, cell density and the content of matrix proteins were higher than those of either single species. Planktonic B. cereus was more susceptible to GLUT than P. fluorescens. The biocide susceptibility of dual species planktonic cultures was an average of each single species. Planktonic cells were more susceptible to GLUT than their biofilm counterparts. Biofilm inactivation was similar for both of the single biofilms while dual biofilms were more resistant than single species biofilms. GLUT at 200 mg l71 caused low biofilm removal (510%). Analysis of the post-biocide treatment data revealed the ability of biofilms to recover their activity over time. However...

Silver colloidal nanoparticles : effect on matrix composition and structure of Candida albicans and Candida glabrata biofilms

Monteiro, D. R.; Silva, Sónia Carina; Negri, M.; Gorup, L. F.; Camargo, E. R.; Oliveira, Rosário; Barbosa, D. B.; Henriques, Mariana
Fonte: Wiley; Blackwell Publishing Inc. Publicador: Wiley; Blackwell Publishing Inc.
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
37.08%
Aim : The aim of this study was to assess the effect of different silver nanoparticles (SN) concentrations on the matrix composition and structure of Candida albicans and Candida glabrata biofilms. Methods and Results : Candida biofilms were developed in 6-well microtiter plates during 48 h. After, these biofilms were exposed to 13·5 or 54 μg SN ml−1 for 24 h. Then, extracellular matrices were extracted from biofilms and analysed chemically in terms of proteins, carbohydrates and DNA. To investigate the biofilm structure, scanning electron microscopy (SEM) and epifluorescence microscopy were used. SN interfered with the matrix composition of Candida biofilms tested in terms of protein, carbohydrate and DNA, except for the protein content of C. albicans biofilm. By SEM, Candida biofilms treated with SN revealed structural differences, when compared with the control groups. Further, SN showed a trend of agglomeration within the biofilms. Epifluorescence microscopy images suggest that SN induced damage on cell walls of the Candida isolates tested. Conclusions : In general, irrespective of concentration, SN affected the matrix composition and structure of Candida biofilms and these findings may be related to the mechanisms of biocide action of SN. Significance and Impact of the Study : This study reveals new insights about the behaviour of SN when in contact with Candida biofilms. SN may contribute to the development of therapies to prevent or control Candida infections.

The role of antifungals agents on Candida glabrata biofilms matrix composition

Silva, Sónia Carina; Lourenço, T.; Negri, M.; Henriques, Mariana; Azeredo, Joana; Oliveira, Rosário
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2010 ENG
Relevância na Pesquisa
37.11%
Candida glabrata was considered, for years, a relatively non-pathogenic saprophyte of the normal flora of healthy individuals and as no causative agent of serious infection in humans. However, its high mortality rate and its quick spread confirm the opposite. In fact, due to the widespread and increased use of immunosuppressive therapy together with broad-spectrum antifungal treatments, the frequency of mucosal and systemic infections caused by C. glabrata has increased significantly. Furthermore, biofilms are described as surface associated communities of microorganisms within an extracellular matrix, generally composed of carbohydrate and proteins. Biofilm formation is an important virulence factor for a number of Candida species, as it confers significant resistance to antifungal therapy by limiting the penetration of substances through the matrix and protecting cells from host immune responses. Moreover, little is known about the role of antifungals on C. glabrata biofilms. Thus, the aim of this work was to study the role of fluconazole, itraconazole and amphotericin B on 24 h pre-formed C. glabrata biofilms and specially on their matrix composition. A total of 3 C. glabrata strains isolated from oral, urinary and vaginal tract were used...

Cell-to-cell aggregation in S. epidermidis and its effect on quantification of total and viable bacteria within biofilms

Freitas, Ana Isabel Costa; França, Ângela; Vasconcelos, C.; Vilanova, Manuel; Cerca, Nuno
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 14/09/2011 ENG
Relevância na Pesquisa
37.1%
Biofilms forming on the surface of indwelling medical devices by microorganisms such as Staphylococcus epidermidis, act as a source of acute infections. Since colonization of medical devices represents a serious problem in public healthcare-associated infections, bacteria forming biofilms have been an important issue often studied. Proper quantification of viable bacteria within S. epidermidis biofilms can however be challenging. Often, biofilm quantification of S. epidermidis is performed with colorimetric methods but these do not provide information regarding viable bacteria. CFU counting is often used but in the case of S. epidermidis, a bacteria that normally grows in clusters of cells, sonication is always required in order to obtain individual cells. In older biofilms, the number of dormant bacteria is expected to be higher than in young biofilms. Therefore, disrupting a biofilm structure without damage the cells in older biofilms can be a challenge. Here, biofilm samples of Staphylococcus epidermidis 9142 strain grown for 24, 48 or 72H in TSB supplemented with 0,5% glucose were ressuspended 1 mL of physiological saline solution and sonicated at different cycles. Following sonication biofilms were quantified using three different approaches: colorimetric methods...

La réponse au Farnésol de Candida albicans : production de biofilms et Parenté génétique

Ross, Jean-françois
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
Relevância na Pesquisa
37.08%
C. albicans est une levure pathogène opportuniste. Elle est un agent causal fréquent des infections muco-cutanées. C. albicans peut alterner entre la forme blastospore et mycélium. Cette dernière forme est impliquée dans la formation des biofilms. Le dimorphisme de C. albicans est contrôlé en partie par le phénomène de perception du quorum (quorum sensing) qui en autre, est associé à la molécule farnésol, produit par cette levure. La présence de cette molécule, inhibe la formation d’hyphe par C. albicans et par conséquent limite la formation de biofilms. Certaines souches ne répondent pas au farnésol et nous avons vérifié les hypothèses que : 1) la proportion des Non-Répondeurs (NR) au farnésol est similaire entre les souches de provenance orale et vaginale; 2) la capacité de formation de biofilm varie d’une souche à une autre mais les Non-Répondeurs en produisent en plus grande quantité; 3) la technique RAPD-PCR permettra de regrouper les souches de cette levure suivant leur provenance, leur capacité de formation de biofilm et leur aptitude à répondre au farnésol. La découverte d’une souche vaginale Non-Répondeur nous permet de croire que la proportion de ces souches est similaire entre les deux types de provenance. Les souches caractérisées Non-Répondeurs produisent 30 % plus de biofilm que les Répondeurs en absence de farnésol exogène dans le milieu. En présence de farnésol exogène...

The role of bacterial biofilms in chronic rhinosinusitis.

Psaltis, Alkis James
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008
Relevância na Pesquisa
37.11%
This thesis embodies research investigating the role that bacterial biofilms play in the pathogenesis of chronic rhinosinusitis (CRS). It focuses on their detection on the sinus mucosa of CRS patients and the implications of their presence. Finally, it addresses deficiencies in the innate immune system that may predispose to their development in this condition. Bacterial biofilms are structural assemblages of microbial cells that encase themselves in a protective self-produced matrix and irreversibly attach to a surface. Their extreme resistance to both the immune system as well as medical therapies has implicated them as playing a potential role in the pathogenesis of many chronic diseases. Although their role in many diseases is now well established, their objective presence and importance in CRS remains largely unknown. Chapter 1 of this thesis reviews the current literature pertaining to CRS and biofilms and critically evaluates the small body of research relating to this topic. Chapter 2 describes the development of a sheep model to study the role of bacterial biofilms in rhinosinusitis. It compares the use of traditional electron microscopy (EM) and more recent confocal scanning laser microscopy (CSLM) in the detection of biofilms on the surface of sinus mucosa. The results of this study inferred a causal relationship between biofilms and the macroscopic changes that accompany rhinosinusitis. Furthermore it illustrated the superiority that CSLM has over EM in the imaging of biofilms on sinus mucosa Chapter 3 and 4 outline the results of human studies utilizing the more objective CSLM to evaluate the prevalence of bacterial biofilms on the sinus mucosa of CRS patients and their effect on post-operative mucosal healing. The results of these studies demonstrated a biofilm prevalence of approximately 50% in the CRS population studied and suggested...

The effect of bacterial biofilms on post-sinus surgical outcomes

Psaltis, A.; Weitzel, E.; Ha, K.; Wormald, P.J.
Fonte: Ocean Side Publications Inc Publicador: Ocean Side Publications Inc
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
Relevância na Pesquisa
37.08%
BACKGROUND: Although the existence of biofilms on the sinus mucosa of patients with chronic rhinosinusitis (CRS) is now well established, the role that these structures play remains unclear. It is thought that biofilms may contribute to the recalcitrant and persistent nature that characterizes CRS, but little research exists documenting the effect that they have on postoperative mucosal outcomes. This article presents a retrospective analysis of sinus surgical patients and correlates the presence of biofilms with mucosal outcomes. This study was performed to evaluate the role that bacterial biofilms have on post-sinus surgical outcomes. METHODS: A retrospective analysis of prospectively collected data was performed on 40 patients undergoing endoscopic sinus surgery (ESS) for CRS. Preoperative demographic, clinical, and radiologic data were recorded from each patient and, intraoperatively, sinus culture specimens and mucosal samples were obtained for microbiological and microscopic examination. Biofilm determination was performed using confocal scanning laser microscopy. Postoperatively, patients were followed up for a minimum of 8 months with endoscopic evaluation of their sinonasal mucosa. The presence of ongoing symptoms was recorded also. RESULTS: Bacterial biofilms were found in 20 (50%) of the 40 CRS patients. Patients with biofilms had significantly worse preoperative radiological scores and...

Investigating bacterial biofilms in chronic Rhinosinusitis : an in vitro study, in vivo animal study and a examination of biofilms in human CRS.

Kien, Ha Rach
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2009
Relevância na Pesquisa
37.18%
Introduction Bacterial biofilms have been implicated in the pathogenesis of Chronic Rhinosinusitis (CRS). This thesis consists of a number of separate studies. The results of each study were designed to help provide an evolution of knowledge that could be applied to our subsequent investigations on the topic of bacterial biofilms and chronic rhinosinusitis. In vitro studies were utilized to document the capacity of CRS bacteria to form biofilms as well as to investigate the efficacy of various antimicrobials at high concentrations. Additionally, an in vivo sheep model was developed to examine different biofilm detection techniques. Finally, a study of CRS patients was conducted to investigate the incidence of biofilm related sinus disease. Methods Our in vitro studies used 96 well crystal violet microtiter plate assays to determine the biofilm growth characteristics of S.aureus isolated from patients with CRS. Established biofilms were then subjected various antimicrobial agents, and the degree of biofilm reduction calculated to examine their potential for sinus biofilm treatment. A sheep sinusitis model involved performing endoscopic sinus surgery, occlusion of frontal sinus ostia and the introduction of bacteria. Mucosal specimens were subsequently examined for the presence of bacterial biofilms using transmission electron microscopy (TEM)...

Staphylococcus aureus biofilms: Nemesis of endoscopic sinus surgery

Singhal, D.; Foreman, A.; Jervis-Bardy, J.; Wormald, P.J.
Fonte: Lippincott Williams & Wilkins Publicador: Lippincott Williams & Wilkins
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
37.1%
OBJECTIVES/HYPOTHESIS: Chronic rhinosinusitis (CRS) patients with biofilms have persistent postoperative symptoms, ongoing mucosal inflammation, and recurrent infections. Recent evidence suggests that biofilms of differing species confer varying disease profiles in CRS patients. We aimed to prospectively investigate the effects of Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus influenzae, and fungal biofilms on outcomes following endoscopic sinus surgery (ESS). STUDY DESIGN: Prospective blinded study. METHODS: In this prospective blinded study, 39 patients undergoing ESS for CRS assessed their symptoms preoperatively using internationally accepted standardized symptom scoring systems and quality-of-life measures (10-point visual analog scale, Sino-Nasal Outcome Test-20, global severity of CRS). Their sinonasal mucosa was graded (Lund-Kennedy scale) and extent of radiologic disease on computed tomography scans scored (Lund-McKay scale). Random sinonasal tissue samples were assessed for different bacterial species forming biofilms by using fluorescent in-situ hybridization and confocal laser microscopy. For 12 months after surgery, CRS symptoms, quality of life, and objective evidence of persisting disease were assessed by using the preoperative tools. RESULTS: Different bacterial species combinations were found in 30 of 39 patients; 60% of these 30 biofilms were polymicrobial biofilms and 70% had S aureus biofilms. Preoperative nasendoscopy and radiologic disease severity were significantly worse in patients with multiple biofilms (P = .02 and P = .01...

Characterisation of biofilms in chronic rhinosinusitis and its clinical and immunological consequences.

Foreman, Andrew
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
37.15%
The research contained within the PhD thesis investigates the role of biofilms in chronic rhinosinusitis (CRS). Following an exhaustive literature review of CRS aetiology, pathogenesis and microbiology, the key deficiencies in our understanding of this disease were highlighted; with particular attention paid to potential role biofilms might play in this disease. It was clear from the literature that the issue of the common biofilm-forming organisms in CRS was incompletely understood and that if this was clarified, it could then be used as a basis for more species-specific investigation of biofilms in CRS. Adopting a species-specific approach may facilitate the development of targeted, novel anti-biofilm strategies that could be employed to improve the outcomes of our most recalcitrant patients. This research investigation commenced with a study to directly correlate a newly developed Fluorescence in situ Hybridisation (FISH) protocol with the current gold standard- BacLight staining imaged on the confocal scanning laser microscope (CSLM). Not only did this project validate FISH as a tool for biofilm identification in CRS but also it also clearly elucidated the research scenarios in which each of these complementary techniques could be used. This will assist to guide future research. A larger cohort study then identified S. aureus as the most common biofilm-forming organism in an often polymicrobial mix that may contain fungal biofilms. The clinical relevance and immunological consequences of biofilm characterisation were then explored. A retrospective clinical investigation found that patients with unimicrobial H. influenzae biofilms had mild disease that was highly responsive to current treatment strategies. In contrast...

Bacterial & fungal biofilms in chronic rhinosinusitis.

Singhal, Deepti
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
37.17%
Chronic Rhinosinusitis (CRS) is a recalcitrant disease, characterized by headache, nasal discharge / blockage, which substantially impairs daily functioning and negatively affect quality of life. Endoscopic Sinus Surgery (ESS) is an important treatment option for CRS, but has variable success rates. Biofilms are well organised heterogeneous communities of microbes embedded in a mosaic of extracellular matrix, adherent to biotic / abiotic surfaces. As they are resistant to host defences and medical treatments, they have been touted as possible pathogenic factors in CRS, which may perpetuate the recurrent and recalcitrant character of the disease and negatively affect treatment outcomes. This thesis encompasses research undertaken to enhance our understanding about the effect that presence and types of biofilms have on the clinical profile and treatment outcomes of patients suffering with chronic rhinosinusitis. An in-vitro model of fungal biofilms and a potential tool to assay in-vivo mucosal biofilms on sinonasal tissues has also been described. Chapter 1 of the thesis comprehensively reviews the scientific literature pertaining to biofilms and CRS, and exhaustively evaluates the evidence present in relation to bacterial and fungal biofilms in CRS. Chapter 2 describes a study to investigate the effect of biofilms on outcomes following ESS in CRS patients using internationally accepted standardised symptom scores...

Investigation of the antimicrobial activity of the essential oil of Cymbopogon martini on S. aureus and E. coli biofilms

Millezi, A. F.; Lopes, Susana Patrícia; Piccoli, R. H.; Pereira, Maria Olívia
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 ENG
Relevância na Pesquisa
37.1%
Biofilms are sessile communities of microbial cells embedded in an exopolymeric secreted matrix that can adhere both to abiotic and living surfaces, serving as a permanent source of contamination. Essential oils (EOs) have different characteristics depending on the plant due to a large number of compounds (eugenol, citral, carvacrol, among others). It has been noticed that EOs have promising antibacterial activity that can be explored as an effective alternative to control biofilms. The aim of this study was to assess the antimicrobial activity of the essential oil of Cymbopogon martini against pre-established single biofilms developed by Staphylococcus aureus and Escherichia coli. Biofilms were developed in 96-well microtiter plates for 24 h at 37 ºC, in an orbital shaker at 120 rpm, being afterwards submitted to EOs aggression for 15, 30 e 60 minutes. The essential oil were dissolved in DMSO (2.0 %) and saline water (0.85 %) with tween 80 (0.5 %) in order to obtain final concentrations of 0,12, 0,48, 0,96 and 1,92 %. Biofilms were characterized, before and after EO treatment, by total biomass, through crystal violet (CV), and number of cultivable bacterial cells, expressed as Log CFU per cm2. The C. martini essential oil did not have any effective antimicrobial action against S. aureus biofilms...

Confocal scanning laser microscopy evidence of biofilms in patients with chronic rhinosinusitis

Psaltis, A.; Ha, K.; Beule, A.; Tan, L.W.; Wormald, P.J.
Fonte: Lippincott Williams & Wilkins Publicador: Lippincott Williams & Wilkins
Tipo: Artigo de Revista Científica
Publicado em //2007 EN
Relevância na Pesquisa
37.1%
OBJECTIVES: The recent detection of bacterial biofilms on the sinus mucosa of patients with chronic rhinosinusitis (CRS) has implicated biofilms in the pathogenesis of this condition. Electron microscopy has been the main modality used to document the presence of biofilms on sinus tissue, however, it has inherent problems associated with tissue preparation and sampling. Recently, Confocal Scanning Laser Micrsocopy (CSLM) has emerged as a noninvasive, nondestructive technique for the analysis of biofilms. This study used CSLM as the means of investigating biofilm presence in CRS patients. STUDY DESIGN AND METHODS: A prospective study comparing the presence of bacterial biofilms on the sinus mucosa of CRS and control patients was conducted using CSLM. Thirty eight CRS patients undergoing endoscopic sinus surgery and nine control patients were enrolled in this study. Demographic and clinical information was recorded from each patient and intraoperatively, sinus culture specimens and mucosal samples were obtained for microbiologic and microscopic examination. RESULTS: Using previously documented CSLM criteria, bacterial biofilms were found in 17 (44%) of the 38 CRS patients. No biofilm structures were evident in any of the controls. Patients having undergone previous sinus surgery seemed to have a higher incidence of biofilms compared with the incidence for those undergoing their first procedure. The difference however was not statistically significant. No correlation between positive bacterial cultures and biofilm presence was observed. CONCLUSIONS: The CSLM detection of biofilms in CRS patients and their absence in controls further supports the hypothesis that biofilms may play a role in the pathogenesis of CRS. This study's lower reported incidence of biofilms compared with that of previous studies might reflect the increased accuracy of biofilm detection with CSLM.; http://www.ncbi.nlm.nih.gov/pubmed/17603329; Article first published online: 2 JAN 2009

Étude de l’effet d'agents potentiellement perturbateurs de la structure des biofilms sur la diffusion des macromolécules dans les biofilms de Streptococcus mutans : cas de l’EDTA et de l’aspirine

Madoda-Nsiambote, Doudou
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
Relevância na Pesquisa
37.15%
Le but de ce travail de mémoire était d'explorer des moyens pour augmenter la perméabilité des biofilms de Streptococcus mutans aux macromolécules en utilisant des agents potentiellement perturbateurs de la structure des biofilms. L’acide éthylènediamine tétraacétique (EDTA) ainsi que l’acide acétylsalicylique (aspirine) sont les agents perturbateurs choisis. Le changement de perméabilité des biofilms de S. mutans a été déterminé en mesurant les coefficients de diffusion globale du polyéthylène glycol (PEG) et de diffusion locale de dextrans. Les coefficients de diffusion globale ont été mesurés par spectroscopie infrarouge avec un échantillonnage par réflexion totale atténuée (ATR) alors que la spectroscopie par corrélation de fluorescence (SCF) a été utilisée pour la mesure des coefficients de diffusion locale. Les résultats ont démontré que l’incorporation de l’EDTA à une concentration de 7.5 (m/v) % dans la solution de diffusion permet d’améliorer les propriétés de transport du PEG dans les biofilms en augmentant sa pénétrabilité et son coefficient de diffusion globale. Par contre, aucune variation n’a été constatée dans la valeur du coefficient de diffusion locale de dextran fluorescent. Cette différence peut être expliquée...

Analysis of the virulence of Candida albicans biofilms developed under different conditions = : Análise da virulência de biofilmes de Candida albicans desenvolvidos sob diferentes condições; Análise da virulência de biofilmes de Candida albicans desenvolvidos sob diferentes condições

Yuri Wanderley Cavalcanti
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/02/2015 PT
Relevância na Pesquisa
37.14%
A prevalência das infecções por Candida é elevada; logo, melhor compreensão dos mecanismos de desenvolvimento do biofilme é necessária para a redução da virulência e apropriado manejo clínico. Objetivou-se analisar a virulência de biofilmes de Candida albicans desenvolvidos sob diferentes condições. O papel das superfícies de biomateriais, da película salivar, e do estágio de desenvolvimento dos biofilmes foi avaliado no Capítulo 1. A influência da presença de outros microrganismos na virulência de C. albicans e na interação com o epitélio foi avaliada no Capítulo 2. O papel da atmosfera e da população bacteriana dos biofilmes foi investigado no Capítulo 3. No Capítulo 1, biofilmes de C. albicans foram desenvolvidos sobre discos de resina acrílica e titânio recobertos com película de saliva, ou de saliva com plasma. A superfície dos materiais foi analisada quanto a rugosidade e energia livre de superfície (ELS). Avaliou-se o número de microrganismos viáveis, a concentração de DNA, a atividade metabólica, a expressão de fatores de virulência e a estrutura dos biofilmes. Não houve diferenças quanto a rugosidade das superfícies. A película minimizou as diferenças entre a ELS dos materiais...