Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-07-14T19:24:36Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação lucas pereira 20.01.16 14h.pdf: 3030489 bytes, checksum: d08690f65be6ab72afc4f01820c878d4 (MD5) / Made available in DSpace on 2017-07-14T19:24:36Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação lucas pereira 20.01.16 14h.pdf: 3030489 bytes, checksum: d08690f65be6ab72afc4f01820c878d4 (MD5) Previous issue date: 2014-08-03 / Capes / Em estudos prévios, realizados por Almeida, foram obtidas substâncias 2-isoxazolinas aza-biciclicas, que deram origem a núcleos como o 2-isoxazolina[5,4-b]piperidina e 2- isoxazolina[5,4-b]pirrolidina. Amidas N benzoiladas derivadas dessas substâncias apresentaram-se farmacologicamente ativas, principalmente em testes anti-inflamatório e antimicrobianos realizados com esses compostos. Além disso, várias substâncias contendo a função oxima, em sua forma livre e como éteres de oxima, são descritas na literatura, apresentando atividades biológicas antimicrobianas. Diante disso, foi obtido através da hibridização molecular, derivados 2-isoxazolínicos aza-biciclico contendo a função oxima em sua estrutura. Os ésteres isoxazolínicos 34 e 36 foram obtidos através de reações de cicloadição 1,3-dipolar por duas diferentes rotas sintéticas, pela reação do óxido de nitrila 41 (CEFNO) tanto com o enecarbamato cbz, quanto com as enamidas endocíclicas para-substituídas. Os cicloadutos oriundos do enecarbamato endocíclico, sofreram reações de hidrogenólise e posterior N-benzoilação. A porção éster, presente nos compostos N-benzoilados para-substituídos, foi reduzida a álcool e em seguida submetida a uma oxidação de Swern, resultando nos aldeídos isoxazolínicos. A partir desses aldeídos 38, através de uma reação com hidroxilamina, chegou-se nas oximas isoxazolínicas 39. Os novos derivados foram submetidos a testes biológicos com o intuito de avaliar sua atividade antimicrobiana. O teste foi realizado pelo método de difusão em disco, contendo bactérias Gram negativas e Gram positivas, onde os derivados isoxzolínicos apresentaram halos variados frente aos microrganismos em estudo. O composto 39b caracterizou-se como uma substância promissora no desenvolvimento de novos agentes antimicrobianos, com halos de 10 mm para o Staphylococcus aureus, 11 mm para o Micrococcus luteus, 13 mm Bacillus subtilis e 13 mm para o microrganismo Micobacterium smegmatis. / In previous studies conducted by Almeida substances were obtained isoxazolines 2-azabicyclic, giving rise to nuclei as 2-isoxazoline [5,4-b] piperidine and 2-isoxazoline [5,4-b] pyrrolidine. N benzoiladas amides derived from these substances had become pharmacologically active, especially in anti-inflammatory and antimicrobial tests conducted with these compounds. Furthermore, substances containing various oxime function, in free form and as oxime ethers are described in literature, showing microbial biological activities. Thus, was obtained by molecular hybridization, derivatives aza-bicyclic 2-isoxazolínicos containing the oxime function in its structure. Esters isoxazolínicos 34 and 36 were obtained by cycloaddition 1,3-dipolar cycloaddition reactions of two different synthetic routes, by reaction of the nitrile oxide 41 (CEFNO) with both the cbz enecarbamate, as with the endocyclic enamides para-substituted. Cicloadutos coming from the endocyclic enecarbamate suffered reactions of hydrogenolysis and subsequent N-benzoylation. The ester moiety present in the N-substituted compounds for benzoilados was reduced to alcohol, and then subjected to a Swern oxidation, resulting in isoxazolínicos aldehydes. From these aldehydes 38 by means of a reaction with hydroxylamine, was reached in isoxazolínicas oximes 39. The novel derivatives were subjected to biological tests in order to evaluate its antimicrobial activity. The test was performed using the disk diffusion method, comprising Gram negative and Gram positive where isoxzolínicos halo derivatives showed varied across the microorganisms under study. Compound 39b was characterized as a promising substance in the development of new antimicrobial agents with halos of 10 mm for Staphylococcus aureus, 11 to Micrococcus luteus mm, 13 mm and 13 mm Bacillus subtilis microorganism Mycobacterium smegmatis for.

A sepse é uma doença de alta mortalidade e o uso adequado de antimicrobianos no seu manuseio é essencial na obtenção de melhores resultados. O objetivo deste estudo foi avaliar o consumo de antimicrobianos em pacientes com sepse hospitalar com agente etiológico identificado no sangue, comparando a reação em cadeia da polimerase (PCR) - LightCycler® SeptiFast (SF) para a detecção rápida de microorganismos à hemocultura convencional nos primeiros 14 dias de tratamento. Os objetivos secundários incluíram descrever o percentual de positividade e a concordância entre o teste molecular e a hemocultura, o tempo de internação hospitalar, os custos diretos dos antimicrobianos utilizados e a letalidade em 10 e 28 dias. Entre outubro de 2012 e maio de 2016, foram incluídos 200 pacientes adultos com sepse hospitalar: 100 alocados no grupo intervenção onde a terapia antimicrobiana foi ajustada após a identificação do micro-organismo pelo SF (dentro de 6 a 12 horas) e 100 pacientes no grupo controle onde a terapia antimicrobiana foi ajustada após a identificação do microrganismo pela hemocultura (dentro de 48 a 72 horas). O consumo de antimicrobianos foi de 1429 (1071-2000) DOT por 1000 pacientes-dia no grupo intervenção versus 1889 (1357-2563) DOT por 1000 pacientes-dia no grupo controle (p = 0.017). O SF apresentou positividade de 25,9% enquanto a positividade da hemocultura foi de 22,9% (p = 0,452). O tempo de descalonamento antimicrobiano foi de 8 horas (7-14) versus 54 horas (38-75) (p < 0,001), enquanto a mortalidade em 10 e 28 dias foi de 21% e 36,8% no grupo de intervenção versus 37% e 44% no grupo controle, (p = 0,710 e p = 0,632), respectivamente. Não houve diferença no tempo de internação hospitalar e no custo direto dos antimicrobianos utilizados nos dois grupos. A duração média da terapia antimicrobiana em dias foi menor no grupo intervenção (12 ± 5 versus 15 ± 4, p = 0,039) em comparação com o grupo controle / Sepsis is a high mortality disease. Appropriate use of antimicrobials is essential to improve outcomes. The aim of the present study was to determine whether the use of the multiplex polymerase chain reaction LightCycler® SeptiFast (SF) assay reduces the antibiotic consumption through early de-escalation in patients with nosocomial sepsis compared with conventional blood cultures (BC) in the first 14 days of treatment. Secondary outcomes included the percentage of microorganisms identified through SF and BC (in both groups), timing of antimicrobial de-escalation, length of stay, direct costs of the antimicrobial drugs and mortality at 10 and 28 days. Between October 2012 and May 2016 adult patients with nosocomial sepsis were randomized in intervention group and control group: antimicrobial therapy was adjusted following the identification of microorganisms by SF (within 6 to 12 hours) or BCs (within 48 to 72 hours), respectively. A total of 200 patients were included (100 in each group). The median antimicrobial consumption was 1429 (1071-2000) DOT/1000 patients-day in the intervention group versus 1889 (1357-2563) DOT/1000 patients-day in the control (p = 0.017). Microorganism identification was 25.9% versus 22.9% (p = 0.452), timing of antimicrobial de-escalation was 8 hours (7-14) versus 54 hours (38-75) (p < 0.001) while the mortality rate at 10 and 28 days was 21% and 36.8% in the intervention group versus 37% and 44% in the control group, (p = 0.710 and p = 0.632), respectively. There was no difference in length of stay and antimicrobial costs between groups. The mean duration of antimicrobial therapy was lower in the SF group (12 ± 5 vs. 15 ± 4, p = 0.039) comparing to BC group. The use of a rapid molecular blood test resulted in a reduction in the antimicrobial consumption and a more rapid de-escalation in patients with nosocomial sepsis when compared to the standard management of blood culture

Infectious diseases are the major cause of human death worldwide and the need for new generations of anti-infective agents to overcome the drug resistant urgently needs to be tackled. Plant natural products are potential sources of novel antimicrobial compounds. In this study, an investigation into the antimicrobial lead compounds from Michelia figo, Macleaya cordata and Ardisia gigantifolia in Lingnan region is presented. The prevention of dental diseases is targeted at the control of dental biofilm. Streptococcus mutans and S. sobrinus are the leading bacterial strains in the formation of dental biofilm. Extracts of Michellia figo and Macleaya cordata displayed antimicrobial potential in our screening assays. Bioassay-guided isolation of M. figo revealed the presence of artabotryside B and acteoside which were isolated for the first time from this plant. Moreover, chelerythrine and sanguinarine, the two alkaloids isolated from Macleaya cordata displayed the ability to prevent the formation of biofilms of S. mutans and S. sobrinus with the MIC50 values in the range of 18.5-34.0 μM. Anti-TB bioassay-guided isolation of the extract of Ardisia gigantifolia led to isolation of two 5-alkylresorcinols, 5-(8Z-heptadecenyl) resorcinol (1) and 5-(8Z-pentadecenyl) resorcinol (2). We further synthesized 15 derivatives based on these two compounds. Resorcinols 1 and 2 exhibited anti-TB activity with MIC values at 34.4 μM and 79.2 μM in MABA assay, respectively, and 91.7 μM and 168.3 μM in LORA assay, respectively. Among these derivatives, compound 8 was found to show improved anti-TB activity than its synthetic precursor (2) with MIC values at 42.0 μM in MABA assay and 100.2 μM in LORA assay. Chelerythrine and sanguinarine are the representative and the major active constituents of M. cordata. Both compounds showed significant fungicidal effects in vitro and significant therapeutic effects on guinea pigs of dermatophytosis. Mechanism study for the antifungal efficacy showed that chelerythrine and sanguinarine were potent inhibitors of ergosterol bio-synthesis by reducing the amount of ergosterol without affecting the synthesis of 1,3-β-glucan. In summary, these results highlight the promising antimicrobial activity of chelerythrine, sanguinarine and alkylresorcinols from the medicinal plants in Lingnan region. The active compounds may be regarded as new hits for further study as novel classes of antimicrobial agents for the treatment of infectious diseases.

Orientador: Márcio Garcia Ribeiro / Banca: Simone Baldini Lucheis / Banca: Paulo Francisco Domingues / Banca: Daniel Moura de Aguiar / Banca: Geraldo de Nardi Junior / Resumo: Nas últimas décadas é crescente o número de infecções por enterobactérias oportunistas multidroga resistentes em animais domésticos e humanos, em geral secundárias ao uso abusivo de antimicrobianos, incluindo pelo gênero Proteus. No entanto, as infecções por linhagens do gênero Proteus em animais domésticos são negligenciadas, relegadas ao segundo plano ou, por vezes, o micro-organismo é considerado "contaminante", ainda que em infecções como agente primário. Os registros de infecções por Proteus sp. em animais domésticos estão praticamente restritos aos relatos de casos, estudos retrospectivos ou compondo estudos com outros micro-organismos. São restritos no Brasil os estudos sistematizados envolvendo os principais aspectos clínico-epidemiológicos das afecções pelo gênero Proteus em grande número de animais domésticos, tampouco da presença de linhagens multirresistentes e/ou produtoras de beta-lactamases de espectro estendido (ESBL). O presente estudo investigou o índice de resistência múltipla (IRMA) e a concentração inibitória mínima (CIM) de 73 isolados de Proteus mirabilis (n=69) e Proteus vulgaris (n=4) a diferentes antimicrobianos, bem com a produção fenotípica de ESBL, em isolados obtidos de várias manifestações clínicas em animais domésticos. Em cães, o micro-organismo foi identificado predominantemente em casos de cistite (48,21%), enterite (21,42%), otite (14,29%), conjuntivite (3,57%), dermatite (1,79%), artrite (1,79%) e em secreção de ferida cirúrgica (1,79%). Nos bovinos, o agente foi isolado de casos enterite (22,22%), abscesso (11,11%), otite (11,11%), onfalite (11,11%), peritonite (11,11%), metrite (11,11%) e em fragmento de órgão (11,11%). Nos equinos, enterite (50,0%), artrite (22,22%) e abscesso (16,67%) foram as principais afecções clínicas, enquanto nos felinos o agente foi isolado exclusivamente de casos de enterite (100,0%). A maior sensibilidade dos isolados no... / Abstract: In the last decades have been highlighted the increase number of infections in domestic animals and humans caused by opportunistic multidrug resistant enterobacteria, commonly associated to improper use of antimicrobials, including by Proteus species. However, Proteus infections in domestic animals have been misdiagnosed or the microorganism is considered a contaminant of microbiological cultures, besides to be a primary agent of diseases. Descriptions of Proteus infections in domestic animals usually are restricted to case reports, retrospective studies or part of studies involving other microorganisms. In Brazil, are restricted the comprehensive studies involving the main clinical and epidemiologic aspects of Proteus infections in a great number of domestic animals, as well as multiple drug resistant strains to conventional antimicrobials, and extended-spectrum beta-lactamase producers (ESBL). The present study investigated multiple antibiotic resistance index, minimum inhibitory concentration (MIC), and ESBL production in 73 strains of Proteus mirabilis (n=69) and Proteus vulgaris (n=4) isolated from different clinical manifestations in domestic animals. In dogs, the pathogen was identified most commonly causing cystitis (48.21), enteritis (21.42%), otitis (14.29%), conjuntivitis (3.57%), dermatitis (1.79%), arthritis (1.79%), and from surgical wound secretion (1.79%). In bovines, the microorganism occurred predominantly in enteritis (22.22%), abscesses (11.11%), otitis (11.11%), omphalitis (11.11%), peritonitis (11.11%), and in organ fragments (11.11%). Among equines, diarrhea (50.0%), arthritis (22.22%), and abscesses (16.67%) were the most common clinical manifestations, whereas in domestic cats the agent was identified exclusively in two cases of enteritis. In vitro standard disk diffusion method showed that the most effective antimicrobials against strains were imipenem (98.63), norfloxacin (95.89), amikacin (95.89), levofloxacin ... / Doutor

M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Sciences) Vaal University of Technology. / Chemical precipitation method is the most widely used of all methods for preparing good quality semiconductor nanoparticles. Several conditions are optimized for producing the desired size and shape of particles. The parameters such as capping molecule, precursor concentration, time and temperature were investigated using the colloidal hot injection method. The effect of capping agent was the first parameter investigated in the synthesis of copper selenide, copper sulphide and copper oxide nanoparticles. The capping agents of interest in this study were oleylamine (OLA) and trioctylphosphine (TOP), due to their ability to act as reducing agents, surfactant, solvent and enhancement of colloidal stabilization. The use of oleylamine and trioctylphosphine were carried out at 220 °C for 30 minutes. The optical and structural properties of the yielded nanoparticles were characterize using UV/Vis spectroscopy, TEM and XRD and showed dependence on the type capping interactions from the two agents. Nanoparticles synthesized using TOP produced two phases whereas a single phase was observed from OLA as confirmed by XRD. OLA produced bigger particle sizes compared to TOP but with a wider variety of shapes. The wide variety of particle structures of OLA capped nanoparticles was advantageous since different types of bacteria were targeted in this work. Therefore, other synthetic parameters were investigated using OLA as both solvent and capping molecule. Precursor concentration ratio showed bigger effect in the size, and shape of the yielded nanoparticles. For copper selenide and copper sulphide (Cu: Se/ S), 1:1 concentration ratio gave the best optical and structural properties while copper oxide (CuO) nanoparticles demonstrated its best optical and structural properties in 2:1 ratio (Cu: O). Nonetheless, 1:1 precursor concentration ratio was used to optimise other parameters. Since reaction time has a profound effect on the nanocrystals size and shapes, the effect of reaction time in OLA was also investigated. The reaction time showed no effect on the phase composition of the synthesized copper sulphide, copper oxide and copper selenide nanoparticles. Reaction time of 30 minutes gave the best optical (the shape of the absorption band edge and emission maxima values) and structural (size distribution of particles) properties for CuSe and CuS compared to other reaction times (15 min, 45 and 60 min). 15 min reaction time gave the best optical and structural properties for copper oxide but nonetheless, 30 min was used as the optimum reaction time for further optimization. Temperature showed an effect in size, shape and the stoichiometry of the reaction. These effects were confirmed by the optical and structural properties of the synthesized nanoparticles. XRD patterns revealed some differences with the temperature change, indicating an effect on the phase composition of CuS and CuO but not on CuSe nanoparticles. CuSe and CuS nanoparticles synthesized at 220 °C gave the ideal optical and morphological features compared to other temperatures that were selected (160 ºC, 190 ºC and 240 ºC). Nonetheless, CuO revealed its best optical and structural properties at 160 ºC. 220 ºC was deduced to be the optimum temperature for the synthesis of these three materials under the synthetic conditions. The optimum parameter (220 ºC, 30 min and 1:1 ratio) were used to synthesize the three copper chalcogenides which were then tested against Gram-negative (E. coli and P. aeruginosa), Gram-positive (S. aureus and E. faecalis), and fungi (C. albicans). The plant species, Combretum molle and Acacia mearnsii were phytochemical screened for the presence of active organic compounds and the content of total phenols, flavonoids and antioxidants using different solvents. Both C. molle and A. mearnsii revealed the highest phenolic content in acetone extracts. C. molle revealed its highest flavonoid content in methanol extract and its highest free radical scavenging activity in acetone extract. Acetone extracts demonstrated the highest flavonoid content as well as the highest free radical scavenging activity of A. meansii. The solubility of copper chalcogenides and plant extract was tested in four different solvents and the solvent that demonstrated highest solubility was used for the coordination of the plant extract and copper chalcogenides. The plant extract coordinated nanoparticles were tested for their antibacterial and antifungal activity. Their results were compared to those of the active ingredient in their respective solvents from the medicinal plants as well as those of copper chalcogenides nanoparticles without plant extracts using diffusion disk and MICs methods. The synthesized nanoparticles showed better performance than plant extracts with copper oxide performing the best, followed by copper selenide and lastly by copper sulfide. The performance of plants extracts highly dependent on the solvent of extract with acetone showing the best performance for both C. molle and A. Mearnsii followed by ethanol. The addition of active ingredients from C. molle and A. mearnsii to the synthesized nanoparticles did not enhance the performance of these nanoparticles.

No description available.

tudies in teaching and non-teaching hospitals have shown that one- quarter to one-third of all patients receive an antimicrobial (AMC) drug during their hospital stay." 1-30 Many of these patients (ranging from 30 to 60%), particularly those on the surgical services, have no definite evidence of infection. Inquiry regarding the use of AMC drugs can be traced back more than two decades. In 1961, the Commission on Professional and Hospital Activities in its Professional Activity Study (CPHA-PAS) surveyed 24 hospitals." They found that approximately 27% of all patients were given an AMC drug; however, it was estimated by PAS that only about 12% of these patients should have received AMC therapy under the most conservative medical practice.

The primary mode of growth for bacteria in the environment and during infection is as a biofilm–multicellular assemblages encased in a self-produced matrix. Bacteria growing in biofilms must contend with the difficulties of resource limitation and competition in order to reap the benefits of increased protection from external stresses including the antibiotics used against them. With the rise in multi-drug resistance, understanding the interplay of the complicated processes that make this growth style possible will help us develop better treatment options. Cells must maintain redox homeostasis in order to carry out metabolism and avoid death. In the pathogen Pseudomonas aeruginosa, oxygen is the preferred terminal electron acceptor used for this purpose. However, oxygen is often scarce under natural growth conditions, where opposing rates of diffusion and consumption lead to the formation of steep gradients. Under conditions of oxygen limitation, the metabolically versatile P. aeruginosa can use two major redox balancing strategies: (i) denitrification (i.e., respiration of exogenous nitrate) and (ii) reduction of endogenous redox-active pigments called phenazines. The work in this thesis describes novel regulatory mechanisms for redox homeostasis with an emphasis on the biofilm lifestyle. Chapter 1 will introduce the necessary background about redox pathways and homeostasis in P. aeruginosa, and how this organism senses chemical cues and transduces this information into physiological adjustments that support metabolic activity and survival. Chapter 2 highlights the remarkable versatility of P. aeruginosa in producing multiple terminal oxidases, particularly the cbb3-type terminal oxidases encoded by partially redundant operons, which have the potential to generate 16 isoforms. The interaction between small-molecule virulence factors, such as cyanide, and the respiratory chain adds complexity to this system. This study uncovers the regulatory role of MpaR, a predicted pyridoxal phosphate-binding transcription factor, in governing expression of a cbb3-type terminal oxidase subunit in response to endogenous cyanide. Chapter 3 demonstrates that pyocyanin, a terminal phenazine product, promotes metabolic activity at a depth in biofilms. However, production of pyocyanin and precursor products is stressful to cells particularly when electron donors are limiting. This work presents the global regulators RpoS and Hfq/Crc as regulators of phenazine production to balance toxicity and metabolic support. Finally, Chapter 4 identifies the first member of the P. aeruginosa phosphotransferase system, PtsP, as an oxygen-independent regulator of phenazine production and denitrification. The research presented in this thesis sheds light on P. aeruginosa’s adaptive tactics for thriving under adverse conditions. Understanding the physiology of this bacterium under conditions relevant to biofilm-based infection provides insights into its strategies for long-term colonization in host environments and opens the door for development of more effective antimicrobials in the face of a world-wide antibiotic crisis.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Biosurfactants are microbially produced molecules that show excellent surface-active properties. Bacillus subtilis ATCC 21332 produces the biosurfactant, surfactin, which exhibits antimicrobial activity against bacteria as well as fungi. Although antimicrobial activity has been exhibited by a number of bacterially produced biosurfactants, notably the rhamnolipid from the pathogen Pseudomonas aeruginosa, the GRAS status B. subtilis makes the use of this organism preferable for large scale bioprocesses. The objectives of this study were to: (1) evaluate the effect of different nutrient conditions on growth and surfactin production; (2) evaluate the growth of B. subtilis ATCC 21332 and associated surfactin production on a hydrocarbon substrate; (3) evaluate the antimicrobial activity of surfactin against Mycobacterium aurum, and (4) to establish whether active growth of B. subtilis ATCC 21332 and associated surfactin production can be extended during fed-batch culture. B. subtilis ATCC 21332 was grown on low-nitrate; phosphate-limited and nutrient rich media with glucose as substrate during shake flask culture. Nitrate, phosphate, glucose and surfactin were quantified by HPLC analyses and growth via CDW and optical density measurements. Growth and surfactinproduction were further evaluated during shake flask cultureon a hydrocarbon substratereplacing the glucose in the nutrient rich medium with an equivalent amount of n-hexadecane. The antimicrobial activity was quantified by growth inhibition of M. aurum. Bioreactor batch and fed-batch studies were conducted to evaluate growth and surfactin production under controlled conditions. The fed-batch experiments included four constant dilution rate (D=0.40h-1; D=0.15h-1; D=0.10h-1 and D=0.05h-1) and two constant feed rate (F=0.40L/h and F=0.125L/h) fed-batch strategies. The nutrient rich medium was used for these experiments and also as the feed medium for fed-batch experiments. A CDW of 12.6 g/L was achieved in the nutrient rich medium during shake flask culture and was 2.5- and 1.6-fold higher than that achieved in the phosphate-limited medium and the lownitrate medium respectively. A surfactin concentration of 652 mg/L was achieved in the nutrient rich medium, while a maximum surfactin concentration of 730 mg/L was achieved in the phosphate-limited medium. A surfactin concentration of only 172 mg/L was achieved in the low-nitrate medium. Subsequently, growth and surfactin production were evaluated on n-hexadecane as sole carbon source. After inoculation, the CDW did not increase over a period of 119 h, which indicated that B. subtilis ATCC 21332 was unable to utilize n-hexadecane for growth and surfactin production. The maximum CDW (27 g/L) and maximum surfactin concentration (1737 mg/L) achieved in the bioreactor batch experiments were 2.1- and 2.6-fold higher respectively than that achieved in the nutrient rich medium during shake flask experiments. These results served as a benchmark for further fed-batch experiments. During the fed-batch phase of the D=0.40h-1 experiment, the biomass further increasedby 9 g/h, which was 3.5-, 3.1- and 5.3-fold higher compared to the fed-batch phases of the D=0.15h-1, D=0.10h-1 and D=0.05h-1 experiments respectively. Similarly, the biomass increased by 10.7 g/h during the fed-batch phase of the F=0.40L/h experiment, which was 4.6-fold higher than that of the F=0.125L/h experiment. The average rate of surfactin production was 633 mg/h during the fed-batch phase of the D=0.40h-1 experiment, 29.4-, 5.4- and 34.2-fold higher compared to the fed-batch phases of the D=0.15h-1, D=0.10h-1 and D=0.05h-1 experiments respectively. Analogously, the average rate of surfactin production (544 mg/h) of the F=0.40L/h experiment was 9.4 fold higher than that of the F=0.125L/h experiment. The antimicrobial assay showed that surfactin inhibits M. aurum growth. An inhibition zone diamater of 4mm was measured at a surfactin concentration of 208 mg/L, which linearly increased to 24mm at a surfactin concentration of 1662 mg/L. High feed flow rate strategies achieved higher rates of biomass increase and surfactin production and will thus decrease the production time required for large scale surfactin production.The antimicrobial activity of surfactin against M. aurum indicates that this biosurfactant has the potential to be used against M. tuberculosis, and as such has the potential to be used in the medical industry to reduce the spread of this, and other deadly diseases. / AFRIKAANSE OPSOMMING: Biosurfaktante is oppervlak-aktiewe molekules wat deur sekere mikro-organismes geproduseer word. Bacillus subtilis ATCC 21332produseer ‘n biosurfaktant genaamd surfactin, wat antimikrobiese eienskappe toon teen bakterieë sowel as fungi.Menige bakterieël geproduseerde biosurfaktante toon antimikrobiese eienskappe, vernaam die rhamnolipied van die patogeen Pseudomonas aeruginosa, maar die algemene veiligheids-status van B. subtilis gee voorkeur aan hierdie organisme vir grootskaalse bioprosesse. Die doelwitte van hierdie studie was: (1) om die effek van verskillende medium samestellings (in terme van voedingstowwe) ten opsigte van bakteriële seldigtheid en surfactin-produksie te evalueer; (2) om die bakteriële seldigtheid van B. subtilis ATCC 21332 en geassosieerde surfactin produksie vanaf ‘n alkaan-substraat te evalueer; (3) om die antimikrobiese aktiwiteit van surfactin teen Mycobacterium aurum te evalueer; (4) om vas te stel of die aktiewe groei van B. subtilis ATCC 21332 en geassosieerde surfactin-produksie gedurende voer-lot kultuur verleng kan word. B. subtilis ATCC 21332 was op lae-nitraat; fosfaat-beperkte en voedingstofryk-media met glukose as substraat in skudflesse gekultiveer. Nitraat, fosfaat, glukose en surfactin was deur hoëdruk vloeistofchromatografie gekwantifiseer en die seldigtheid deur middel van seldroëmassa en optiese digtheid metings. Verder was die groei van B. subtilis, en geassosieerde surfactin produksie, vanaf ‘n alkaan-substraat in skudflesse ge-evalueer deur die glukose in die voedingstofryke medium met ‘n ekwivalente hoeveelheid van n-heksadekaan te vervang. Die antimikrobiese aktiwiteit van surfactin was deur die geїnhibeerde groei van M. aurum gekwantifiseer. Bioreaktor lot en voer-lot studies was uitgevoer om die groei en surfactin produksie onder beheerde toestande te evalueer. Die voer-lot eksperimente het vier konstante verdunningstempos (D=0.40h-1; D=0.15h-1; D=0.10h-1 en D=0.05h-1) en twee konstante voertempos (F=0.40L/h and F=0.125L/h) ingesluit. Die voedingstofryke medium was vir hierdie eksperimente en ook as die voermedium vir dievoer-lot eksperimente gebruik. ‘n Seldigtheid van 12.6 g/L is bereik gedurende skudfleskultuur in die voedingstofryk-media en was 2.5- en 1.6-voud hoër as die seldigthede wat in die fosfaat-beperkte en lae-nitraat media bereik is. ‘n Surfactin konsentrasie van 652 mg/L is bereik in die voedingstofryke medium, terwyl ‘n maksimum surfactin konsentrasie van 730 mg/L in die fosfaat-beperkte medium bereik is. ‘n Surfactin konsentrasie van slegs 172 mg/L is in die lae-nitraat medium bereik.Hierna was bakteriële seldigtheid en surfactin produksie geuvalueer met slegs n-heksadekaan as die enigste koolstof bron. Die bakteriële seldigtheid het geen verandering getoon na inokulasie nie, wat aangedui het dat B. subtilis ATCC 21332 nie die vermoë beskik om n-heksadekaan vir groei en surfactin produksie te gebruik nie. Die maksimum seldigtheid (27 g/L) en maksimum surfactin konsentrasie (1737 mg/L) bereik in die bioreaktor lot eksperimente was 2.1- en 2.6-voud hoër onderskeidelik as dit bereik in die voedingstofryke medium gedurende skudfles eksperimente. Hierdie resultate dien as ‘n basis vir verdere voer-lot eksperimente. Gedurende die voer-lot fase van die D=0.40h-1 het die biomassa verder verhoog teen 9 g/h, wat 3.5-, 3.1- en 5.3-voud hoër was as dit van die D=0.15h-1, D=0.10h-1 en D=0.05h-1 eksperimente onderskeidelik. Die biomassa het soortgelyk tydens die voer-lot fase van die F=0.40L/h eksperiment teen 10.7 g/h verhoog, wat 4.6-voud hoër was as dit van die F=0.125L/h eksperiment. Die gemiddelde tempo van surfactin produksie was 633 mg/h gedurende die voer-lot fase van die D=0.40h-1 eksperiment, 29.4-, 5.4- en 34.2-voud hoër vergeleke met die voer-lot fases van die D=0.15h-1, D=0.10h-1en D=0.05h-1 eksperimente onderskeidelik. Die gemiddelde tempo van surfactin produksie (544 mg/L) was soortgelyk 9.4-voud hoër gedurende die voer-lot fase van die F=0.40L/h eksperimente, vergeleke met die die F=0.125L/h eksperiment. Die antimikrobiese toetse van surfactin teen M. aurum het positief getoets, wat aandui dat surfactin die groei van hierdie organisme inhibeer. ‘n Inhibisie sone deursnee van 4mm was gemeet teen ‘n surfactin konsentrasie van 208 mg/L, wat lineêr verhoog het tot 24 mm teen ‘n surfactin konsentrasie van 1662 mg/L. Hoë voertempo strategieë het hoër biomassa verhogingstempos en surfactin produksie tempos getoon en sal dus die produksietyd aansienlik verkort tydens grootskaalse surfactin produksie. Die antimikrobiese aktiwiteit van surfactin teen M. aurum toon dat hierdie biosurfaktant die vermoë het om gebruik te word teen M. tuberculosis. Daarom het surfactin die potensiaal om gebruik te word in die mediese industrie om die verspreiding van Tuberkulose, en ander dodelike patogene, te voorkom.

Este estudo investigou a resistência à tração (ou limite de resistência à tração- LRT) e a porosidade de reembasadores resilientes temporários modificados por concentrações inibitórias mínimas (CIMs) de agentes antifúngicos para o biofilme Candida albicans (SC5314). Para os testes de LRT, corpos de prova em forma de halteres (n=7) com uma área transversal de 33 mm x 6 mm x 3 mm foram produzidos para os materiais resilientes (Trusoft e Softone) sem (controle) ou com incorporação de cinco fármacos em suas CIMs: nistatina- 0,032 g; diacetato de clorexidina- 0,064; cetoconazol- 0,128 g; miconazol- 0,256 g; itraconazol-0,256 g (grama de fármaco por grama de pó de material resiliente). Após a plastificação, as amostras foram imersas em água destilada a 37°C durante 24 h, 7 e 14 dias e, então, testadas em tensão em uma máquina universal de ensaios (EMIC DL-500 MF) a 40 mm/min. A porosidade foi mensurada por absorção de água, com base na exclusão do efeito plastificante. Inicialmente, determinou-se por isotermas de sorção, que a solução de armazenagem adequada para os corpos de prova (65 mm x 10 mm x 3,3 mm) de ambos os materiais foi o cloreto de cálcio anidro a 50% (S50). Assim, o fator de porosidade (FP) foi calculado para os grupos de estudo (n=10) formados por espécimes sem (controle) ou com incorporação de fármaco em suas CIMs (nistatina, clorexidina ou cetoconazol) após a armazenagem em água destilada ou S50 por 24 h, 7 e 14 dias. Os dados de resistência à tração (MPa) e percentagem de alongamento (%) foram submetidos à ANOVA de 3 fatores seguida pelo teste de Tukey (=0,05). Os dados de porosidade foram analisados estatisticamente por ANOVA de medidas repetidas para 4 fatores e teste de Tukey (=0,05). Ao final de 14 dias, a resistência à tração para ambos os materiais foi significativamente menor nos grupos modificados pelo miconazol e itraconazol em relação aos outros grupos (P<0,0001), que não mostraram diferenças significativas entre si (P>0,05). Após 7 e 14 dias em água, o miconazol e itraconazol adicionados a ambos os materiais resultaram em percentagens significativamente menores de alongamento em comparação com os outros fármacos e ao controle (P<0,0001), que foram semelhantes entre si (P>0,05). O cetoconazol não resultou em alterações significativas no FP para ambos os materiais resilientes em água ao longo de 14 dias (P>0,05). Em comparação aos controles, houve aumento dos FPs do Softone e Trusoft aos 14 dias de imersão em água somente após a adição de nistatina e clorexidina e de clorexidina, respectivamente (P<0,05). Ambos os materiais não apresentaram alterações significativas no FP em até 14 dias de imersão na S50, em comparação aos controles (P>0,05). Em todas as condições experimentais, os FPs do Softone e Trusoft foram significativamente menores quando imersos em S50 em comparação com a água destilada (P<0,05). Concluiu-se que a adição de nistatina, clorexidina e cetoconazol nas CIMs para o biofilme de C. albicans não resultou em efeitos deletérios na resistência à tração e na percentagem de alongamento dos materiais resilientes temporários para base de prótese até o período de 14 dias. A adição de antifúngicos nas CIMs não resultou em efeitos adversos à porosidade de ambos os materiais resilientes temporários em diferentes períodos de imersão em água, com exceção da clorexidina e nistatina no Softone e clorexidina no Trusoft aos 14 dias. Não foram observados efeitos deletérios para a porosidade de ambos os materiais resilientes modificados com as CIMs dos fármacos durante os 14 dias de imersão na S50. / This study investigated the tensile strength (ultimate tensile strength- UTS) and porosity of temporary soft denture liners modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm (SC5314). For UTS tests, dumbbell-shaped specimens (n=7) with a central cross-sectional area of 33 mm x 6 mm x 3 mm were produced by resilient materials (Trusoft and Softone) without (control) or with incorporation of five drugs at MICs: nystatin- 0.032 g; chlorhexidine diacetate-0.064 g; ketoconazole- 0.128 g; miconazole- 0.256 g; itraconazole- 0.256 g (each per gram of soft liner powder). After plasticization, specimens were immersed in distilled water at 37°C for 24 h, 7 and 14 days, and then tested in tension in a universal testing machine (EMIC DL-500 MF) at 40 mm/min. The porosity was measured by water absorption, based on exclusion of the plasticizer effect. Initially, it was determined by sorption isotherms that the adequate storage solution for specimens (65 mm x 10 mm x 3.3 mm) of both materials was 50% anhydrous calcium chloride (S50). Then, the porosity factor (PF) was calculated for the study groups (n=10) formed by specimens without (control) or with drug incorporation at MICs (nystatin, chlorhexidine or ketoconazole) after storage in distilled water or S50 for 24 h, 7 and 14 days. Data of tensile strength (MPa) and elongation percentage (%) were submitted to 3-way ANOVA followed by Tukey\'s test (=0.05). Data of porosity were statistically analyzed by 4-way repeated measures ANOVA and Tukeys test (=0.05). At the end of 14 days, the tensile strength for both materials was significantly lower in the groups modified by miconazole and itraconazole compared to the other groups (P<0.0001), which showed no significant difference between them (P>0.05). After 7 and 14 days in water, miconazole and itraconazole added into both materials result in significant lower elongation percentages compared to the other drugs and control (P<.0001), which were similar to each other (P>0.05). Ketoconazole resulted in no significant changes in PF for both liners in water over 14 days (P>0.05). Compared to the controls, Softone and Trusoft PFs were increased at 14-day water immersion only after addition of nystatin and chlorhexidine, and chlorhexidine, respectively (P<0.05). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared to the controls (P>0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared to distilled water (P<0.05). It was concluded that the addition of the nystatin, chlorhexidine and ketoconazole at MICs for C. albicans biofilm resulted in no harmful effects on the ultimate tensile strength and elongation percentage of the temporary soft denture liners up to 14-day period. The addition of antifungals at MICs resulted in no detrimental effects for the porosity of both temporary soft liners in different periods of water immersion, except for chlorhexidine and nystatin in Softone and chlorhexidine in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion.