<p>Cape Town includes two vegetable farming areas within the city limits, the Joostenbergvlakte/Kraaifontein area and the Philippi area. Both areas supply produce to local markets and further afield. Sporadically, high levels of cadmium, copper, lead and zinc have been found to occur in some of the soils, irrigation water resources and crops. To find the sources of specifically Cd, Pb and Zn to these agricultural systems, extensive analysis of several heavy metals in inputs such as fertilizers, agrochemicals and supplementary water resources to these farming areas was undertaken. Heavy metal concentrations in soils, irrigation water resources and crops were also determined. Two mitigation techniques that could be used to remediate Cd, Pb and Zn contamination were investigated. The first mitigation method included immobilization of heavy metals as phosphate complexes by using a triple super phosphate fertilizer, while the second method involved mobilisation and thus leaching of heavy metals away from plant roots using EDTA. These mitigation methods were tested in a pot experiment using cabbage as the experimental crop and soil from these areas as growth medium. A survey of common farming practices in these two areas and farmers willingness to use remediation methods was conducted.</p>

In this project the factors influencing the stability and antimicrobial activity of allyl isothiocyanate (AITC) against Campylobacter jejuni, Salmonella or Listeria monocytogenes as well as factors that enhance sinigrin (glucosinolate in Oriental mustard) hydrolysis by these pathogens were investigated. The minimum inhibitory concentration (MIC) of AITC against 5 strains of each of Salmonella or L. monocytogenes, ranged from 60-100 ppm at 37 ºC. This was reduced to 10-40 ppm at 21 ºC and a further reduction to 5-10 ppm against strains of L. monocytogenes was observed at 4 ºC. This was attributed to greater stability of AITC as temperature was decreased. C. jejuni strains were more susceptible to AITC with MICs of 0.63-1.25 ppm and 2.5-5 ppm at 37 and 42 ºC, respectively. AITC was more inhibitory at ≤ 21 ºC against Salmonella with acidic pH or against L. monocytogenes with neutral pH. C. jejuni, Salmonella and L. monocytogenes strains and mixtures had the ability to degrade sinigrin to form inhibitory concentrations of AITC, and sinigrin hydrolysis was significantly enhanced by higher incubation temperature (21 ºC > 10 ºC > 4 ºC), the presence of 10 mM ferric or ferrous irons, and the presence of < 0.25% glucose. This project also investigated the antimicrobial activity of AITC or Oriental mustard extract alone or combined with ethylenediamine tetraacetic acid (EDTA), malic acid and acetic acid in edible antimicrobial coatings against C. jejuni and Salmonella on fresh, refrigerated, vacuum-packed chicken breasts or L. monocytogenes on refrigerated, cured roast chicken. Malic acid improved the antimicrobial activity of Oriental mustard extract against L. monocytogenes, while EDTA improved its activity against Salmonella. Incorporation of 25 to 50 µl/g AITC or 100 to 250 mg/g Oriental mustard extract in 0.5%κ-carrageenan/2%chitosan coatings, prepared using 1.5% malic or acetic acid, reduced L. monocytogenes on cooked, cured, vacuum-packed chicken slices 4.2 to > 7.0 log10 CFU/g, compared to uncoated chicken by 70 d at 4 ºC. In addition, 0.2%κ-carrageenan/2%chitosan coatings (prepared using a 1% acetic acid solution) containing 250 mg/g mustard extract or 50 µl/g AITC reduced Salmonella numbers on vacuum-packed chicken breasts 3.0 log10 CFU/g by 21 d at 4 ºC. Further, 0.2%κ-carrageenan/2%chitosan coatings containing 50 or 100 µl/g AITC reduced numbers of C. jejuni on fresh, vacuum-packed chicken breasts > 5.0 log10 CFU/g (C. jejuni cells were not detected) after 5 d storage at 4 ºC, while coatings containing 200 to 300 mg/g Oriental mustard extract or 25 µl/g AITC reduced C. jejuni numbers by 3.6 to 4.6 log10 CFU/g. Numbers of lactic acid and aerobic bacteria on poultry meat products were significantly reduced by the coatings. It is clear that κ-carrageenan/chitosan coatings containing either AITC, mustard extract alone or combined with EDTA, malic or acetic acid significantly reduced C. jejuni and Salmonella on fresh, refrigerated, vacuum-packed chicken breasts and L. monocytogenes on refrigerated, cured roast chicken, and consequently enhanced their safety.

La gesse commune (Lathyrus sativus L.) est une légumineuse cultivée principalement en Inde, au Bangladesh et en Ethiopie qui présente des niveaux de résistance élevés pour de nombreuses contraintes abiotiques, telles que la sécheresse et l'inondation. Dans ce travail, les capacités de tolérance du Lathyrus (lignées locales " Raipur " et " Bangladesh ") à une autre contrainte abiotique, la présence de plomb, ont été déterminées des points de vue physiologique et moléculaire. Un système expérimental de culture hydroponique a été mis au point pour ces plantes. Le plomb y est introduit sous forme de nitrate de plomb (Pb(NO3)2). Les teneurs en plomb des différents organes des plantes (racines, tiges, feuilles) ont été déterminées par ICP-OES. Les réponses cellulaires dans ces organes ont été étudiées par RTPCR quantitative (PCR en temps réel). Des amorces spécifiques du Lathyrus ont été dessinées à partir des 11 séquences d'ADN complémentaires (ADNc) isolées pour la première fois et séquencées. L'un des ADNc isolé est complet et code une cystéine protéase (LsCP, 427 aa). Les autres sont des ADNc partiels et correspondent à une aspartique protéase (LsAP, 270 aa), deux ascorbate peroxidases cytosolique (LsAPXc, 195 aa) et peroxisomale (LsAPXp, 226 aa), une protéine de choc thermique (" Heat Shock Protein 70 " ; LsHSP70, 287), une homoglutathion synthétase (LshGSHS, 329 aa), une glutathion S-transférase (LsGST, 66 aa), une glutathion réductase (LsGR, 336 aa), une phytochélatine synthétase (LsPCS, 64 aa), une phospholipase D a (LsPLDa, 288 aa), un transporteur membranaire spécifique du Pb (LsCNGC, 136) et une protéine soluble (LsABCt, 331 aa). Les plantes exposées au nitrate de plomb accumulent de grandes quantités de métal dans leurs racines sous forme de plomb fortement lié aux tissus. L'accumulation d'ARN messagers de la LsPLDa suggère que les racines subissent une contrainte cellulaire et s'y adaptent. La stimulation de l'expression des gènes LsGST, LsGR et LsAPX correspondrait à la formation de complexes Pb-glutathion et à une activation du cycle ascorbate-glutathion pour la neutralisation des espèces activées de l'oxygène (ROS) délétères. Dans les feuilles exemptes de plomb, l'augmentation de l'expression des gènes LsCP, LsAP, LsAPXc, LsAPXp, LsHSP70, LsGR et LsPCS semble indiquer l'émission d'un signal racinaire transmis de manière systémique vers le reste de la plante où il déclenche la sur-expression de ces gènes. Ceci pourrait permettre aux tissus épargnés par le polluant de se préparer à son éventuelle arrivée. La chélation du Pb avec de l'EDTA dans le milieu de culture conduit à son transport vers les parties aériennes et à son accumulation dans les feuilles. L'expression du gène LsCNGC chez ces plantes est activée dans les feuilles, suggérant une participation de ce transporteur à l'entrée des complexes Pb-EDTA dans le symplasme. Comme observé chez d'autres espèces végétales, le plomb affecte le métabolisme du glutathion chez la gesse commune. Cependant, la mise en évidence d'une réaction systémique en réponse au plomb à partir des racines ainsi que la surexpression de gènes d'autolyse sont réalisées pour la première fois et pourraient être des éléments contribuant fortement à la tolérance au plomb chez cette espèce végétale sous-utilisée.

Phosphorus (P) is an essential element for life on our planet. It is central in numerous biochemical processes in terrestrial and aqueous ecosystems including food production; and it is the primary growth-limiting nutrient in some of the world’s biomes. The main source of P for use as agricultural fertilizer is mining of non-renewable mineral phosphate. In terrestrial ecosystems the main source is soil P, where the largest fraction is organic P, composed of many species with widely differing properties. This fraction controls the utilization of P by plants and microorganisms and influences ecosystem development and productivity. However, there is only scarce knowledge about the molecular composition of the organic P pool, about the processes controlling its bioavailability, and about its changes as soils develop. Therefore, the aim of this thesis was to develop robust solution- and solid-state 31P nuclear magnetic resonance spectroscopy (NMR) methods to provide molecular information about speciation of the organic P pool, and to study its dynamics in boreal and tropical soils. By studying humus soils of a groundwater recharge/discharge productivity gradient in a Fennoscandian boreal forest by solution- and solid-state NMR, it was found that P speciation changed with productivity. In particular, the level of orthophosphate diesters decreased with increasing productivity while mono-esters such as inositol phosphates increased. Because the use of solution NMR on conventional NaOH/EDTA extracts of soils was limited due to severe line broadening caused by the presence of paramagnetic metal ions, a new extraction method was developed and validated. Based on the removal of these paramagnetic impurities by sulfide precipitation, a dramatic decrease in NMR linewidths was obtained, allowing for the first time to apply modern multi-dimensional solution NMR techniques to soil extracts. Identification of individual soil P-species, and tracking changes in the organic P pools during soil development provided information for connecting P-speciation to bioavailability and ecosystem properties. Using this NMR approach we studied the transformation of organic P in humus soils along a chronosequence (7800 years) in Northern Sweden. While total P varied little, the composition of the soil P pool changed particularly among young sites, where also the largest shift in the composition of the plant community and of soil microorganisms was observed. Very old soils, such as found Africa, are thought to strongly adsorb P, limiting plant productivity. I used NMR to study the effect of scattered agroforestry trees on P speciation in two semi-arid tropical woodlands with different soil mineralogy (Burkina Faso). While the total P concentration was low, under the tree canopies higher amounts of P and higher diversity of P-species were found, presumably reflecting higher microbial activity. / <p>I delarbete III har titel och författaruppgifter förändrats.</p>

Submitted by Gisele Mara Hadlich (gisele@ufba.br) on 2017-11-08T17:26:17Z No. of bitstreams: 1 NURIA_DISSERTA.pdf: 2389644 bytes, checksum: 4e22a20a8e92fd654c38e74451d5d61a (MD5) / Made available in DSpace on 2017-11-08T17:26:17Z (GMT). No. of bitstreams: 1 NURIA_DISSERTA.pdf: 2389644 bytes, checksum: 4e22a20a8e92fd654c38e74451d5d61a (MD5) / O presente trabalho tem como objetivo avaliar a disponibilidade, mobilidade e distribuição dos metais-traço (Cd, Cr, Cu, Fe, Mg, Ni, Pb e Zn) em áreas cultivadas com olericólas do município de Jaguaquara, Bahia. Para avaliar a disponibilidade, distribuição e/ou mobilidade dos metais nos solos oriundos de aportes antropogênicos, como uso intensivo de agroquímicos, são utilizados diferentes métodos de extração, designados parciais (EDTA e água régia), digestão total ou extração sequencial (utilização de uma série de extratores, também conhecido com extração sequencial). A extração parcial promove a retirada dos metais fracamente adsorvidos nas frações geoquímicas; total também os teores não lábeis. Os métodos de fracionamento químico visam avaliar os metais associados desde a fração trocável até os metais que estão fortemente ligados na fração residual, com a utilização de reagentes seletivos sob condições experimentais específicas para cada etapa de extração. Neste trabalho foram realizadas extração sequencial, extração parcial (EDTA e água régia) e digestão total em 37 amostras de solos cultivados (0-20 cm). Para o fracionamento foi utilizado o método proposto por Tessier et al. (1979), adaptado. Foram realizadas também as seguintes análises: granulometria, pH, Eh, matéria orgânica (MO), nitrogênio total (N), fósforo assimilável (P), capacidade de troca catiônica (CTC). Os metais-traço Ni e Cr (digestão com EDTA) permaneceram abaixo dos limites de detecção em todas as amostras. Análises estatísticas mostraram que há diferenças significativas entre os métodos estudados e em relação aos parâmetros físico-químicos e a distribuição dos metais. Os parâmetros que mais interferem na distribuição dos metais (extração EDTA e água régia) são granulometria, pH, MO e P. O fracionamento químico revelou distribuições diferenciadas dos metais nas frações geoquímicas de solos e sedimentos. Os metais Cr, Pb e Zn apresentaram distribuição diferenciada nas frações; já o Pb apresentou sempre uma maior proporção na fração residual. Com o Fator de Mobilidade foi possível verificar a ordem de mobilidade dos metais Cr >Pb > Zn. Uma comparação entre os métodos mostrou que o EDTA extrai os metais mais facilmente disponíveis, a água régia, extraiu além, desses os metais com menos disponibilidade, e a digestão total extraiu principalmente os metais não disponíveis para ambiente.

O advento do uso de cateteres venosos centrais na prática médica trouxe muitos benefícios aos pacientes, porém está relacionado a um aumento na incidência de infecções por microrganismos multirresistentes. Além disso, freqüentemente ocorre colonização por bactérias produtoras de biofilme. Estes microrganismos se aderem ao material abiótico desses dispositivos intravenosos, ficando protegidos sob a matriz exopolissacarídica do biofilme. Isso faz com que sistema imunológico e antimicrobianos sejam incapazes de ter sua ação plena e, muitas vezes, não atingem os microrganismos mais internos. O motivo deste insucesso é porque muitos desses agentes biológicos e farmacológicos apresentam propriedades físico-químicas incompatíveis com a penetração nesta matriz. Com o objetivo de determinar quais antimicrobianos são mais adequados para uso quando o microrganismo é produtor de biofilme e quais as propriedades físico-químicas que estão diretamente relacionadas à penetração do antimicrobiano na matriz polissacarídica, utilizou-se método colorimétrico com cristal violeta em microplacas modificado para obtenção de concentração inibitória mínima em biofilme (MBIC) e método já padronizado para concentração inibitória mínima (MIC). Para isso foram testados 10 antimicrobianos em Staphylococcus spp.: rifampicina, azitromicina, claritromicina, eritromicina, levofloxacino, gentamicina, doxiciclina, cloranfenicol, clindamicina e vancomicina. Para Pseudomonas aeruginosa foram testados os mesmos, exceto rifampicina e vancomicina. A discrepância entre MIC e MBIC foi muito grande para vários fármacos, mostrando a necessidade de se avaliar estes parâmetros antes do início da farmacoterapia para uma escolha correta, especialmente em hospitais. Os fármacos que apresentaram melhores resultados foram a rifampicina e os macrolídeos, enquanto que os menos efetivos foram vancomicina e clindamicina. Isso foi atribuído ao perfil lipofílico, porém com alguma solubilidade em água das melhores moléculas. Em contra ponto, a elevada área polar, complexidade e massa molar foram características negativas para a penetração em biofilme, resultando numa ineficácia para essas moléculas. Além disso, também foi avaliado o tratamento de polímeros plásticos com EDTA, obtendo-se redução significativa da produção de biofilme nas placas tratadas com o agente químico. / The use of central venous catheters in medicine has brought benefits to the patients and represents a great advance in clinical practice, while on the other hand this device is related to an increase in the incidence of infections caused by multiresistant pathogens. Furthermore, frequently, the catheters get colonized by biofilm producing bacteria. These microorganisms adhere to the abiotic material of the catheters keeping themselves protected underneath the exopolysaccharide matrix of biofilm, this way the immune system and antimicrobials are incapable to fulfill their action and, many times, are unable to reach internal bacteria. This fact is explained by the fact that many of the biological and pharmacological agents have physical-chemical properties incompatible with the penetration into the matrix. Aiming to determine which antimicrobials are suitable for using when dealing with a biofilm producing microorganism and which physical-chemical properties are directly related to the agent penetration into the polysaccharide matrix, we used colorimetric method with crystal violet to obtain biofilm minimum inhibitory concentration (MBIC) and the already standardized method for minimum inhibitory concentration (MIC). To accomplish these 10 antimicrobials were tested in Staphylococcus spp.: rifampin, azithromycin, clarithromycin, erythromycin, levofloxacin, gentamicin, doxycycline, chloramphenicol, clindamycin and vancomycin. For Pseudomonas aeruginosa all antimicrobials except for rifampin and vancomycin were included. There was a great difference between MIC and MBIC for many drugs, showing the need to evaluate these parameters before beginning treatment. The drugs with better results were rifampin and macrolides, while the worse were vancomycin and clindamycin, which can be attributed to the lipophilic profile with some water solubility present in the molecules with better results. The characteristics associated with poor penetration into biofilm were high polar surface area, complexity e molecular weight. Furthermore, the previous treatment of the plastic polymers with EDTA was accessed resulting in statistically significant reduction of biofilm production.

Made available in DSpace on 2014-10-09T12:44:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:46Z (GMT). No. of bitstreams: 1 07160.pdf: 4424646 bytes, checksum: 4938889fd9a885e62dfeaafc99b1274d (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-15T19:53:06Z No. of bitstreams: 1 AngelicaBelchiorVital_DISSERT.pdf: 1925266 bytes, checksum: 0be77624e1435efb79973666de949fea (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-19T20:48:44Z (GMT) No. of bitstreams: 1 AngelicaBelchiorVital_DISSERT.pdf: 1925266 bytes, checksum: 0be77624e1435efb79973666de949fea (MD5) / Made available in DSpace on 2016-04-19T20:48:44Z (GMT). No. of bitstreams: 1 AngelicaBelchiorVital_DISSERT.pdf: 1925266 bytes, checksum: 0be77624e1435efb79973666de949fea (MD5) Previous issue date: 2015-01-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Compostos contendo rut?nio possuem vasta aplica??o em processos catal?ticos. Muitas vezes esse metal ? utilizado em ?xidos porosos , suporte, com alta estabilidade t?rmica. Os ?xidos mistos do tip o perovskita (ABO 3 ) apresentam boa dispers?o met?lica , elevada estabilidade t?rmica e qu?mica, sendo empregados em processos oxidativos . Em vista disso, este trabalho teve como objetivo principal sintetizar e caracterizar o catalisador de rutenato de b?rio (BaRuO 3 ) com estrutura do tipo perovskita. Para isso, foram utilizadas duas metodolog ias de s?ntese de BaRuO 3 , a complexa??o combinada EDTA - Citrato e a coprecipita??o em meio oxalato. BaRuO 3 produzido passou por tratamentos t?rmicos a 950?C por 5, 10 e 15 horas. O precursor foi utilizado na an?lise termogravim?trica (TG) para avaliar a estabilidade t?rmica, e os p?s cer?micos calcinados foram caracterizados por: difra??o de raios X (DRX) para identifica??o das fases formadas , an?lise estrutural e avalia?? o do tamanho m?dio de cristalitos; microscopia eletr?nica de varredura (MEV) para observa??o da morfologia; espectroscopia de energia dispersiva (EDS) para determina??o da composi??o qu?mica local. Observou - se que pela metodologia EDTA - Citrato o BaRuO 3 apr esentou estrutura rombo?drica com o grupo espacial R - 3mH (ICSD: 10253) com morfologia heterog?ne a e com larga distribui??o de tamanho de cristais. Por outro lado, o ?xido sintetizado pelo m?todo de coprecipita??o apresentou dois polimorfos, um com estrutura hexagonal com o grupo e spacial P63/mmc (ICSD:84652) e outro rombo?drico (ICSD:10253), com morfologia homog?nea e maior controle de distribui??o de cristais. / Ruthenium compounds are widely use d in catalytic processes. Often this metal is supported on porous oxides having high thermal stability. Perovskite - type o xides (ABO 3 ) have good metal dispersion , high thermal and chemical s tability, it are used in oxidative processes . T his study aimed to synthesize and characterize barium ruthenate (BaRuO 3 ) with perovskite - type structure. For this, two methods for BaRuO 3 synthesis have been used , combined complexation EDTA - Citrate and oxalat e coprecipitation. BaRuO 3 produced underwent heat treatment at 950 ? C for 5, 10 and 15 hours. The precursor was used in thermogravimetric analysis (TG) to evaluate thermal stability , ceramic powders obtained were characterized by X - ray diffraction (XRD) t o identify the phases, structural analysis and assessment of the average size of crystallites; scanning electron microscopy (SEM) to observe the morphology; energy dispersive spectroscopy (EDS) to determine local chemical composition. It was observed that BaRuO 3 for EDTA - citrate methodology presented rhombohedral structure with space group R - 3mH ( ICSD : 10253) heterogeneous morphology with a broad distribution and crystal size. thereby , the oxide synthesized by oxalate coprecipitation method presented two po lymorphs, with hexagonal structure with space group P63/ mmc ( ICSD : 84652) and a rhombohedral ( ICSD : 10253) with homogeneous morphology and crystals distribution control.

O advento do uso de cateteres venosos centrais na prática médica trouxe muitos benefícios aos pacientes, porém está relacionado a um aumento na incidência de infecções por microrganismos multirresistentes. Além disso, freqüentemente ocorre colonização por bactérias produtoras de biofilme. Estes microrganismos se aderem ao material abiótico desses dispositivos intravenosos, ficando protegidos sob a matriz exopolissacarídica do biofilme. Isso faz com que sistema imunológico e antimicrobianos sejam incapazes de ter sua ação plena e, muitas vezes, não atingem os microrganismos mais internos. O motivo deste insucesso é porque muitos desses agentes biológicos e farmacológicos apresentam propriedades físico-químicas incompatíveis com a penetração nesta matriz. Com o objetivo de determinar quais antimicrobianos são mais adequados para uso quando o microrganismo é produtor de biofilme e quais as propriedades físico-químicas que estão diretamente relacionadas à penetração do antimicrobiano na matriz polissacarídica, utilizou-se método colorimétrico com cristal violeta em microplacas modificado para obtenção de concentração inibitória mínima em biofilme (MBIC) e método já padronizado para concentração inibitória mínima (MIC). Para isso foram testados 10 antimicrobianos em Staphylococcus spp.: rifampicina, azitromicina, claritromicina, eritromicina, levofloxacino, gentamicina, doxiciclina, cloranfenicol, clindamicina e vancomicina. Para Pseudomonas aeruginosa foram testados os mesmos, exceto rifampicina e vancomicina. A discrepância entre MIC e MBIC foi muito grande para vários fármacos, mostrando a necessidade de se avaliar estes parâmetros antes do início da farmacoterapia para uma escolha correta, especialmente em hospitais. Os fármacos que apresentaram melhores resultados foram a rifampicina e os macrolídeos, enquanto que os menos efetivos foram vancomicina e clindamicina. Isso foi atribuído ao perfil lipofílico, porém com alguma solubilidade em água das melhores moléculas. Em contra ponto, a elevada área polar, complexidade e massa molar foram características negativas para a penetração em biofilme, resultando numa ineficácia para essas moléculas. Além disso, também foi avaliado o tratamento de polímeros plásticos com EDTA, obtendo-se redução significativa da produção de biofilme nas placas tratadas com o agente químico. / The use of central venous catheters in medicine has brought benefits to the patients and represents a great advance in clinical practice, while on the other hand this device is related to an increase in the incidence of infections caused by multiresistant pathogens. Furthermore, frequently, the catheters get colonized by biofilm producing bacteria. These microorganisms adhere to the abiotic material of the catheters keeping themselves protected underneath the exopolysaccharide matrix of biofilm, this way the immune system and antimicrobials are incapable to fulfill their action and, many times, are unable to reach internal bacteria. This fact is explained by the fact that many of the biological and pharmacological agents have physical-chemical properties incompatible with the penetration into the matrix. Aiming to determine which antimicrobials are suitable for using when dealing with a biofilm producing microorganism and which physical-chemical properties are directly related to the agent penetration into the polysaccharide matrix, we used colorimetric method with crystal violet to obtain biofilm minimum inhibitory concentration (MBIC) and the already standardized method for minimum inhibitory concentration (MIC). To accomplish these 10 antimicrobials were tested in Staphylococcus spp.: rifampin, azithromycin, clarithromycin, erythromycin, levofloxacin, gentamicin, doxycycline, chloramphenicol, clindamycin and vancomycin. For Pseudomonas aeruginosa all antimicrobials except for rifampin and vancomycin were included. There was a great difference between MIC and MBIC for many drugs, showing the need to evaluate these parameters before beginning treatment. The drugs with better results were rifampin and macrolides, while the worse were vancomycin and clindamycin, which can be attributed to the lipophilic profile with some water solubility present in the molecules with better results. The characteristics associated with poor penetration into biofilm were high polar surface area, complexity e molecular weight. Furthermore, the previous treatment of the plastic polymers with EDTA was accessed resulting in statistically significant reduction of biofilm production.

O advento do uso de cateteres venosos centrais na prática médica trouxe muitos benefícios aos pacientes, porém está relacionado a um aumento na incidência de infecções por microrganismos multirresistentes. Além disso, freqüentemente ocorre colonização por bactérias produtoras de biofilme. Estes microrganismos se aderem ao material abiótico desses dispositivos intravenosos, ficando protegidos sob a matriz exopolissacarídica do biofilme. Isso faz com que sistema imunológico e antimicrobianos sejam incapazes de ter sua ação plena e, muitas vezes, não atingem os microrganismos mais internos. O motivo deste insucesso é porque muitos desses agentes biológicos e farmacológicos apresentam propriedades físico-químicas incompatíveis com a penetração nesta matriz. Com o objetivo de determinar quais antimicrobianos são mais adequados para uso quando o microrganismo é produtor de biofilme e quais as propriedades físico-químicas que estão diretamente relacionadas à penetração do antimicrobiano na matriz polissacarídica, utilizou-se método colorimétrico com cristal violeta em microplacas modificado para obtenção de concentração inibitória mínima em biofilme (MBIC) e método já padronizado para concentração inibitória mínima (MIC). Para isso foram testados 10 antimicrobianos em Staphylococcus spp.: rifampicina, azitromicina, claritromicina, eritromicina, levofloxacino, gentamicina, doxiciclina, cloranfenicol, clindamicina e vancomicina. Para Pseudomonas aeruginosa foram testados os mesmos, exceto rifampicina e vancomicina. A discrepância entre MIC e MBIC foi muito grande para vários fármacos, mostrando a necessidade de se avaliar estes parâmetros antes do início da farmacoterapia para uma escolha correta, especialmente em hospitais. Os fármacos que apresentaram melhores resultados foram a rifampicina e os macrolídeos, enquanto que os menos efetivos foram vancomicina e clindamicina. Isso foi atribuído ao perfil lipofílico, porém com alguma solubilidade em água das melhores moléculas. Em contra ponto, a elevada área polar, complexidade e massa molar foram características negativas para a penetração em biofilme, resultando numa ineficácia para essas moléculas. Além disso, também foi avaliado o tratamento de polímeros plásticos com EDTA, obtendo-se redução significativa da produção de biofilme nas placas tratadas com o agente químico. / The use of central venous catheters in medicine has brought benefits to the patients and represents a great advance in clinical practice, while on the other hand this device is related to an increase in the incidence of infections caused by multiresistant pathogens. Furthermore, frequently, the catheters get colonized by biofilm producing bacteria. These microorganisms adhere to the abiotic material of the catheters keeping themselves protected underneath the exopolysaccharide matrix of biofilm, this way the immune system and antimicrobials are incapable to fulfill their action and, many times, are unable to reach internal bacteria. This fact is explained by the fact that many of the biological and pharmacological agents have physical-chemical properties incompatible with the penetration into the matrix. Aiming to determine which antimicrobials are suitable for using when dealing with a biofilm producing microorganism and which physical-chemical properties are directly related to the agent penetration into the polysaccharide matrix, we used colorimetric method with crystal violet to obtain biofilm minimum inhibitory concentration (MBIC) and the already standardized method for minimum inhibitory concentration (MIC). To accomplish these 10 antimicrobials were tested in Staphylococcus spp.: rifampin, azithromycin, clarithromycin, erythromycin, levofloxacin, gentamicin, doxycycline, chloramphenicol, clindamycin and vancomycin. For Pseudomonas aeruginosa all antimicrobials except for rifampin and vancomycin were included. There was a great difference between MIC and MBIC for many drugs, showing the need to evaluate these parameters before beginning treatment. The drugs with better results were rifampin and macrolides, while the worse were vancomycin and clindamycin, which can be attributed to the lipophilic profile with some water solubility present in the molecules with better results. The characteristics associated with poor penetration into biofilm were high polar surface area, complexity e molecular weight. Furthermore, the previous treatment of the plastic polymers with EDTA was accessed resulting in statistically significant reduction of biofilm production.