Orientador: Antonio Fernando Ribeiro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-11T18:35:30Z (GMT). No. of bitstreams: 1 Amalfi_LiliamMachado_M.pdf: 5120878 bytes, checksum: c21489142714302bf486eaaa938cf04c (MD5) Previous issue date: 2007 / Resumo: Considerando que a fibrose cística é a mais importante doença hereditária, potencialmente letal, incidente na raça branca, que a infecção pulmonar é reconhecida por ter o maior papel na morbimortalidade levando à morte prematura em 90% dos pacientes, e que a principal causa das exacerbações é as infecções recorrentes ou crônicas; torna-se fundamental para um centro de referência, o conhecimento do perfil microbiológico de seus pacientes. A correlação entre a exacerbação dos sintomas pulmonares e a contagem de colônias de bactérias na cultura rotina diagnóstica (CRD) serve para orientar o controle das infecções. Norteados por este fundamento, para o perfil microbiológico utilizaram-se resultados CRD do: Registro eletrônico do Paciente (REP), Arquivo do Laboratório de Microbiologia (ALM) e Prontuário do paciente (PP). As três bases dados pertencem à mesma casuística, sendo que os dois últimos foram utilizados para verificar a coerência entre os perfis e estudo da susceptibilidade. Estatística: x2, Fisher, Pearson, regressão linear, e, nível significância p<0.05 e IC 95%. Foram resgatados 38.480 registros do REP, referentes a 975 CRD's, 402 nos ALM's e 371 dos PP's. Foram isoladas: Pseudomonas aeruginosa em 80,9% REP (43% pertenciam ao morfotipo não mucóide), nos ALM em 70,8% (43% não mucóide) e em 100% dos PP (60,6% não mucóide) e; Staphylococcus aureus em (50,1% REP, 48% ALM, e em 55% PP). Microrganismos emergentes como Burkholderia cepacia em (3,69% REP, 1% ALM, e em 3,5% dos PP's), Strenotrophomonas maltophilia em (3% REP, 2,8% ALM e 1,6% PP). Observamos uma elevada prevalência dos P. aeruginosa, durante o 1° ano de vida (57%), diferença significante se comparadas aos resultados da Cystic Fibrosis Fundation e Consenso Europeu que relatam uma prevalência de 20% entre 0-5 anos. Em relação à prevalência da B. cepacia, foi utilizado o meio seletivo, elevando a prevalência para 13% no ano de 2003, e, se observados ao longo dos anos, o valor se assemelha aos demais estudos (3,6%). Em relação ao estudo de susceptibilidade antimicrobiana, foram encontradas 13 cepas de P.aeruginosa multidroga-resistente aos 5 antibióticos incluídos no estudo (3,23% CRD's em 3 pacientes). Das P.aeruginosa 13,4% foram sensíveis a todos os antimicrobianos (ALM). Foi possível observar resistência das cepas P. aeruginosa aos antibióticos freqüentemente utilizados como a Gentamicina (50%) e Amicacina (31%). As mesmas cepas foram sensíveis à Ceftazidima (45%), Ciprofloxacina (48,7%). Foram isoladas em 389 dos 402 CRD's (ALM), ambos morfotipos (mucóide e não mucóide) apresentando elevada sensibilidade a Ceftazidima, Imipenem e Amicacina (66,9, 56,3% e 60% respectivamente) e, dentre eles, o que apresentou maior eficácia e menor resistência foi a Ceftazidima (5,4%). As cepas de S. aureus apresentaram elevada sensibilidade (72,7% ALM e 100% PP) sendo que dos 183 antibiogramas somente 11 cepas (6% em 5 pacientes ALM) apresentaram-se Oxa-Resistente, apesar de uma prevalência elevada e persistente. O perfil microbiológico, utilizando REP, foi coerente com ALM e PP, sugerindo que dados eletrônicos podem se amoldar às perspectivas de futuras pesquisas, levando-se em consideração a necessidade de novos estudos e maior interação entre as equipes, ajustadas as correções de possíveis vieses / Abstract: Considering that the Cystic Fibrosis is the most important hereditary illness potentially lethal incident in Caucasoid, and the pulmonary infections has been recognized as having the greatest role in the morbid mortality, being cause of death in 90% of the patients, and the main exacerbations cause are the recurrent or chronic infection/ the knowledge in the microbiological profile from patients becomes basic for all reference centers. When infected, the treatment will depends of microorganisms characteristics (antimicrobial resistance and ambient conditions) and, the prognostic depends of the nutritionals and immunological conditions; The correlation between the exacerbation from pulmonary symptoms and the counting of bacteria colonies by the culture routine diagnosis (CRD), serves to guide and control the infections. Guided by this bedding, our objective was to delineate this profile, using the CRD results from: Electronic Patient Register (REP), Archives from Microbiology Laboratory (ALM) and Handbooks of Patient (PP). All the databases belong to the same casuistry, being ALM data and PP collected to verify if the electronic registers correspond to the findings and notations in these archives. For the statistical calculations: descriptive analysis, x2, fisher, correlation Pearson and linear regression and the significance were p <0, 05 and IC 95%. Were analyzed 975 CRD's results between 38.480 registers from REP (100 patients), 402 from ALM (100 patients) and 371(9 patients) from PP's. Were identified: Pseudomonas aeruginosa in 80,9% from REP (43.1% belonged to morphotype mucoid), from ALM in 70,8% (27.8% mucoid) and PP (51.4% mucoid); Staphylococcus aureus in (50.1% REP, 48% ALM, and in 55% PP). Emergent microorganisms as Burkholderia cepacia in (3.69% REP, 1% ALM, and in 3,5% of the PP's), Strenotrophomonas maltophilia in (3% REP, 2.8% ALM and 1.6% PP). In relation of microorganisms prevalence, we observed a high significant prevalence of the Pseudomonas aeruginosa during the first year life (57%), greater than the results from Cystic Fibrosis Foundation and European Consensus (20% of 0-5 yrs). In relation of Burkholderia cepacia prevalence, the selective media was used (year 2003), increasing the prevalence to 13%, if observed during a long period, it would be equivalent to found (3,6%). About antimicrobial susceptibility, 13 of P. aeruginosa multi-drugs resistant were found to all usual antibiotics (3,3% CRD of 3 patients). The P. aeruginosa, 13,4% were sensitive to all antimycrobiane. We observed a great resistance between P. aeruginosa against to usual antibiotics as Gentamicine (50%) and Amicacine (31%). The same cepas were sensitive to Ceftazidima (45%), Ciprofloxacin (48,7%). Of 389 CRD's (ALM), were simultaneously found the both morphotypes (mucoid and nonmucoid) that showed a high sensitive to Ceftazidima, Imipenem e Amicacin (66,9, 56,3% e 60%) and the more effective and less resistant was Ceftazidima (5,4%). The Staphylococcus aureus were high sensitive (72,7% ALM and 100% PP) and just 11 cepas in 183 (5,9%) were Oxa-Resistant in 5 patients, even thought the high and persistent prevalence. The microbiological profile of cystic fibrosis patient from REP corresponds to the results from ALM and PP, suggesting that the electronic register can be molder to the perspectives of future researches, with news studies on this subject, and to plan more interaction between teams to correct any possible vises to appropriate research / Mestrado / Saude da Criança e do Adolescente / Mestre em Saude da Criança e do Adolescente

The packaging does not serve as a mere containment but also can be designed to play a key role in preserving the product from quality-deteriorating factors, including oxygen, light irradiation, and foodborne pathogenic microorganisms (e.g., Escherichia coli). There has been a growing interest in employing ultra-porous metal-organic frameworks (MOF) with visible light-responsive antibacterial mechanisms to generate reactive oxygen species (ROS) that can eliminate bacteria via an oxidative burst. MOF is made of inorganic metal ions/nodes/clusters/secondary building units linked by organic bridge ligands, where titanium dioxide (TiO2) and tetrakis(4-carboxyphenyl)porphyrin) (TCPP) were selected for these components, respectively. TiO2 is an exceptional UV-A/B/C-blocker; meanwhile, TCPP dye performs a remarkable photocatalytic ability even under visible light, on top of its macro-heterocyclic structure that is ideal as a MOF linker. Both have good compatibility but suffer from the notorious tendency to self-quench/aggregate. The incorporation of MOF-based conjugates into a polymeric matrix, like cellulose, is among the proven-successful solutions. Cellulose is the Earth's most abundant and naturally biodegradable, and cellulose nanofibril (CNF) was particularly chosen for its high specific surface area and surface activity. However, a straightforward, cheap, and environmentally friendly approach of multicycle homogenization (0-25 passes) was conducted to solve neat cellulose's challenge of natural hydrophilicity, where low pressure (<10 MPa) was applied to prevent the common over-shearing effect. The antibacterial efficacy of CNF films functionalized with TiO2-TCPP conjugate on inhibiting E. coli growth was analyzed with and without light of different intensities (3000 and 6000 lux). The positive impacts of CNFs' promoted fibrillation and subsequent inter/intra-molecular hydrogen bonding post-homogenization were evidenced in an array of functional properties, i.e., crystallinity, TiO2-TCPP conjugate dispersion, surface smoothness, mechanical properties, thermal stability, hydrophobicity, oxygen barrier (comparable to ethylene-vinyl alcohol (EVOH), a commercial high-barrier polymer), and 100%-antibacterial rate (under 6000 lux after 72 hours). Varying optimum cycles of homogenization demonstrated the prospect of the proposed homogenization approach in preparing CNF with diverse processability and applicability. These findings also exhibited a promising potential for a myriad of high-barrier, UV-blocking, and/or visible light-responsive antibacterial film applications, including food packaging and biomedical. / Doctor of Philosophy / Packaging is useful not only as a container but can also be designed to help prevent products from being spoiled due to various reasons such as oxidation, light, and bacterial contamination. Researchers have discovered the promising antibacterial feature of the metal-organic framework (MOF). Packaging made with MOF technology can harness light and oxygen in the environment to produce a special form of oxygen called reactive oxygen species (ROS) that can kill unwanted bacteria. MOF is an extremely porous sponge-like material made of two ingredients: an inorganic metal cluster and an organic linker; in this study, titanium dioxide (TiO2) and a porphyrin called TCPP were selected, respectively. TiO2 is an excellent ultraviolet blocker, while TCPP has a unique, ring-like geometry that is ideal for use as a linker and an antimicrobial feature that works well under the visible light spectrum. The pair are compatible but still suffer from MOF's notorious challenge, where it tends to clump together because of its tiny size. To resolve this problem, TiO2-TCPP MOF can be deposited evenly in a cast made of polymer. Cellulose has been proven to work effectively as a polymeric cast; moreover, it is natural, biodegradable, and in abundant supply. A type of nanosized cellulose—cellulose nanofibril (CNF)—was specifically chosen because its high surface area and activity are useful when blended with other materials. However, cellulose is naturally a poor water-repellant that is not ideal for packaging applications. As a solution, cellulose can be treated with a homogenization technique by passing the material through a very narrow hole under high pressure. Homogenization can be problematic as it possibly damages the cellulose's structure, and its high pressure can also be expensive and energy consuming. Therefore, low pressure with multiple cycles was applied in this work. CNF-TiO2-TCPP films were tested for their ability to slow down E. coli bacteria growth with and without light of varying brightness to compare its light-sensitive antimicrobial feature. Homogenization was found helpful in producing higher-quality CNF, which improved several of the film's final characteristics, including an even material dispersion, structural order, smoothness, strength, heat resistance, and water repellency. Most importantly, it produced films with oxygen barrier ability comparable to commercial high-barrier plastics and completely eliminated bacteria after 72 hours. The optimum number of homogenization cycles was found to be dependent on the desired characteristics and application. Overall, these findings carry a promising potential for a variety of applications, including food packaging and the biomedical field.

Lee, Ching Ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 90-103). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract --- p.ii / 論文摘要 --- p.iv / Table of Contents --- p.vi / List of Tables --- p.x / List of Figures --- p.xi / Chapter Chapter 1 --- Introduction / Chapter 1.1. --- Quinolone Antimicrobial Agents --- p.1 / Chapter 1.1.1. --- Development --- p.1 / Chapter 1.1.2. --- Mode of action --- p.3 / Chapter 1.1.3. --- Mechanisms of resistance to quinolones --- p.4 / Chapter 1.1.3.1. --- Target genes mutations --- p.4 / Chapter 1.1.3.2. --- Decreased intracellular quinolone accumulation --- p.5 / Chapter 1.1.3.3. --- Plasmid-mediated quinolone resistance --- p.6 / Chapter 1.2. --- Plasmid-mediated Quinolone Resistance Genes (qnr) --- p.8 / Chapter 1.2.1. --- Discovery of qnrA genes --- p.8 / Chapter 1.2.2. --- Discovery of qnrS genes --- p.9 / Chapter 1.2.3. --- Discovery of qnrB genes --- p.10 / Chapter 1.2.4. --- Discovery of qnrC genes --- p.11 / Chapter 1.2.5. --- Discovery of qnrD genes --- p.12 / Chapter 1.2.6. --- Origins of qnr genes --- p.12 / Chapter 1.2.7. --- Qnr proteins and mode of action --- p.14 / Chapter 1.2.8. --- Epidemiology and quinolones resistance activity of qnr genes --- p.16 / Chapter 1.2.9. --- Epidemiology of fluoroquinolone-resistant Enterobacteriaceae --- p.17 / Chapter 1.2.10 --- Multidrug-resistant in extended-spectrum-B-lactamase- and AmpC-producing Enterobacteriaceae --- p.19 / Chapter 1.3. --- Background of Study --- p.20 / Chapter 1.4. --- Objectives of Study --- p.21 / Chapter Chapter 2 --- Materials & Methods / Chapter 2.1. --- Study Design --- p.22 / Chapter 2.2. --- Antimicrobial Susceptibility Testing --- p.24 / Chapter 2.2.1 --- Bacterial isolates --- p.24 / Chapter 2.2.2. --- Screening for ESBL and AmpC production by disk diffusion test --- p.24 / Chapter 2.2.3. --- Determination of minimal inhibitory concentrations (MICs) --- p.25 / Chapter 2.3. --- "Detection of qnrA, qnrB and qnrS Genes by Multiplex PCR" --- p.27 / Chapter 2.3.1. --- Total DNA preparation --- p.27 / Chapter 2.3.2. --- "Multiplex PCR assay for qnrA, qnrB and qnrS genes detection" --- p.27 / Chapter 2.3.3. --- Agarose gel electrophoresis --- p.29 / Chapter 2.4. --- "Detection of TEM-, SHV-, CTX- and PMAmpC Type B-Lactamase Genes by PCR" --- p.30 / Chapter 2.5. --- PCR Assays for Further Genotypic Characterization Purpose --- p.32 / Chapter 2.5.1. --- PCR assay to amplify qnrB genes --- p.32 / Chapter 2.5.2. --- PCR assay to amplify qnrS genes --- p.33 / Chapter 2.5.3. --- "PCR assays for genotypic characterizations of the co-existed blaTEM, blaSHV, blaCTX-M and PMAmpC genes of all qnr-positive isolates" --- p.33 / Chapter 2.5.3.1. --- Genotypic characterizations of the co-existed bla-TEM and genes --- p.33 / Chapter 2.5.3.2. --- PCR assays to amplify the co-existed blaCTX_M genes --- p.33 / Chapter 2.5.3.3. --- PCR assay to amplify the co-existed PMAmpC genes --- p.34 / Chapter 2.5.4. --- Sequencing reaction --- p.36 / Chapter 2.5.4.1. --- Purification of PCR product and sequence determination --- p.36 / Chapter 2.5.4.2. --- Sequence analysis --- p.37 / Chapter 2.6. --- Collection of Clinical Data --- p.38 / Chapter 2.6.1. --- Demographics and clinical data --- p.38 / Chapter 2.6.2. --- Definitions --- p.38 / Chapter 2.6.3. --- Data analysis --- p.40 / Chapter Chapter 3 --- Results / Chapter 3.1. --- Bacterial Isolates --- p.41 / Chapter 3.2. --- "Demographics, Medical History, Clinical Features and Clinical Outcomes of Patients" --- p.42 / Chapter 3.3. --- Antimicrobial Susceptibility Testing --- p.44 / Chapter 3.4. --- Detection of qnr Genes --- p.48 / Chapter 3.4.1. --- "Detection of qnrA, qnrB and qnrS genes by multiplex PCR" --- p.48 / Chapter 3.5. --- Detection of ESBLs --- p.49 / Chapter 3.5.1. --- Detection of TEM- and SHV-type ESBLs --- p.49 / Chapter 3.5.2. --- Detection of CTX-M- type ESBLs --- p.51 / Chapter 3.6. --- Detection of PMAmpC Genes --- p.52 / Chapter 3.6.1. --- Detection of PMAmpC genes --- p.52 / Chapter 3.7. --- "The Distribution of qnr and bla Genes for TEM, SHV, CTX-M and PMAmpC" --- p.53 / Chapter 3.8. --- The Characteristics of qnr Isolates --- p.54 / Chapter 3.8.1. --- Genotypes of qnrB and qnrS --- p.54 / Chapter 3.8.2. --- Antimicrobial susceptibility of qnr isolates --- p.58 / Chapter 3.9. --- "The Associations of qnr Genes with Other Bacterial Resistance Genotypes, and the Clinical Characteristics and Outcomes of Patients" --- p.62 / Chapter 3.9.1. --- "Univariate analysis of the associations of qnr genes with other bacterial resistance genotypes, and the clinical characteristics and outcomes of patients" --- p.62 / Chapter 3.9.2. --- "Multivariate analysis of the associations of qnr genes with other bacterial resistance genotypes, and the clinical characteristics and outcomes of patients" --- p.65 / Chapter 3.9.2.1. --- "Multivariate analysis of the associations of qnr genes with other bacterial resistance genotypes, and the clinical characteristics of patients" --- p.65 / Chapter 3.9.2.2. --- "Multivariate analysis of the associations of mortality with qnr genes, bacterial resistance genotypes and other clinical characteristics of patients" --- p.66 / Chapter Chapter 4 --- Discussion / Chapter 4.1. --- Prevalences and Susceptibility of ESBL and PMAmpC in Bacteraemic Enterobacteriaceae Isolates --- p.67 / Chapter 4.2. --- Epidemiology of Plasmid-mediated Quinolone Resistance (qnr) Genes --- p.69 / Chapter 4.3. --- Genotypes of qnr-positive Isolates --- p.72 / Chapter 4.4. --- Antimicrobial Susceptibility of qnr-positive Isolates --- p.75 / Chapter 4.5. --- "The Associations of qnr Genes with Other Bacterial Resistance Genotypes, and the Clinical Characteristics of Patients" --- p.79 / Chapter 4.6. --- "The Associations of Mortality with qnr Genes, Bacterial Resistance Genotypes and Other Clinical Characteristics of Patients" --- p.80 / Chapter 4.7. --- Clinical Importance and Clinical Implications of qnr Genes --- p.82 / Chapter 4.8. --- Limitations of the Current Study --- p.85 / Chapter 4.9. --- Future Studies --- p.87 / Chapter 4.10. --- Conclusions --- p.89 / References --- p.90

South Africa is home to a wide diversity of cultural groups, all of which utilize the flora for a variety of purposes. This is true with regard to traditional medicine systems which are similar to those of the rest of Africa south of the Sahara, with diviners (sangomas) and herbalists (inyangas) as the key health providers. In addition, the Country is rich in plant diversity with some 30 000 species of flowering plants - almost one tenth of the worlds recorded higher plants. This incorporates a large diversity of plants including trees, shrubs, herbs, bulbs and corms. The adverse effects of traditional medicinal plants and natural products are not well documented in the literature. Recently, many plants used as food or in traditional medicine have been shown to be potentially mutagenic using in vitro assays. Thus, the scientific evaluation of traditional medicine and medicinal plants is very important to validate claims made on safety and efficiency of such usages. After a survey of the available ethnobotanical literature, ten trees used in South African traditional medicine were selected. These species were: Acacia niolotica subspecies kraussiana, Acacia sieberiana, Albizia adianthifolia, Combretum kraussii, Faidherbia albida, Ficus sur, Prunus africana, Salix mucronata, Terminalia sericea and Trichilia dregeana. Plant parts including leaf, root and bark were collected from each of the selected trees (exceptions were Albizia adianthifolia, Faidherbia albida, Terminalia sericea and Prunus africana) and extracted using ethyl acetate, ethanol and water individually to ensure the extraction of compounds over a wide range of polarities. The extracts (in total, 78) were screened for antibacterial, anti-inflammatory (COX-1 and COX-2) and antiacetylcholinesterase activities and investigated for their potential mutagenic effects using the Ames test. Antibacterial activity was detected using the disc-diffusion and microdilution assays. The extracts were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus and Gram-negative bacteria: Escherichia coli and Klebsiella pneumoniae. Of the 78 different plant extracts 111 tested (final amount of plant material was 1 mg per disc), 84% showed activity against Gram-positive bacteria. From this percentage, 20% also showed activity against Gram-negative bacteria. The best inhibition was observed with ethyl acetate and ethanol root extracts of Terminalia sericea against both Gram-positive and Gram-negative bacteria. In the micro-dilution assay, 55% of the plant extracts showed minimum inhibitory concentration (MIC) values ~ 1.56 mg/ml against Gram-positive and/or Gram-negative bacteria. The ethyl acetate bark extract of Acacia sieberiana and the root and bark ethyl acetate extracts of Acacia nilotica inhibited bacterial growth of both Gram-positive and Gram-negative bacteria at concentrations ~ 0.8 mg/ml. The aqueous leaf extracts of Acacia sieberiana had a low MIC value (0.3 mg/ml) against Gram-negative Kleibsiella pneumoniae and the ethyl acetate extracts of the root inhibited growth of Escherichia coli with an MIC value of 0.1 mg/ml. However, these two extracts showed no activity in the disc-diffusion assay. The MIC values of the neomycin (control) were 0.8 I-Ig/ml and 3.1 I-Ig/ml against Kleibsiella pneumoniae and Escherichia coli respectively. In the anti-inflammatory test, 70% of the plant extracts from different plant parts (leaf, root, bark) of the tree investigated showed strong inhibition in both the CQX-1 and CQX-2 bioassays. The CQX-2 inhibitory effects of aqueous extracts were generally lower when compared to the organic solvent extracts. However, water extracts of Acacia nilotica was an exception (~ 90%). In the acetylcholinesterase inhibitory test, 21% of the plant extracts were active at concentrations ~ 1 mg/ml using the micro-plate assay. The lowest IC50 value was 0.04 mg/ml obtained with an ethanol bark extract of Combretum kraussii. The IC50 value of the galanthamine (positive control) was 2 I-IM. None of the investigated plants showed any potential mutagenic effects with Salmonella typhymurium strain TA 98 using the Ames test. Using bioassay-guided fractionation, anolignan B was isolated from the ethyl acetate root extract of Terminalia sericea. Antibacterial activity of anolignan B was determined using the microdilution assay. The compound possessed activity against both Gram-positive and Gram-negative bacteria. The lowest MIC value (3.8 IJg/ml) was observed with Staphylococcus aureus. MIC value of the neomycin was 1.5 IJg/ml. Anti-inflammatory activity of anolignan B was detected using the CQX-1 and CQX-2 bioasays. The compound showed strong inhibitory activity against CQX-1 and weaker activity against CQX-2. The ICso values were 1.5 mM and 7.5 mM with CQX-1 and CQX-2 respectively. The ICso values of indomethacin were 0.003 mM and 0.186 mM against CQX-1 and CQX-2 respectively. There were no potential mutagenic effects showen by anolignan B against Salmonella typhimurium strain TA 98 in the Ames test. Isolation of anolignan B from Terminalia species and the antibacterial and anti-inflammatory activities observed in this work have not been reported previously and could therefore be recorded as novel biological activities for this compound. These results also support the idea that the use of ethnobotanical data can provide a valuable short cut by indicating plants with specific uses which might likely be sources of biologically active chemicals. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Throughout the history of mankind, many infectious diseases have been treated with plant extracts. Venereal infections are one such group and are regarded as conditions that are highly responsive to traditional treatment. Aqueous, ethanol and ethyl acetate extracts of 13 plants used in South Africa for the treatment of venereal diseases were screened for in vitro antibacterial, antifungal, mutagenic and antimutagenic activities. Antibacterial activity was evaluated using the disc-diffusion and microdilution assays to determine the minimal inhibitory concentration (MIC) values of the extracts. The extracts were tested against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, and the Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae. Among the plants tested, Gunnera perpensa, Harpephyllum caffrum, Hypoxis latifolia and Ledebouria ovatifolia showed the best antibacterial activity. The aqueous rhizome extract of Gunnera perpensa displayed good activity against Gram-negative bacteria with an MIC value of 0.78 mg/ml, and against S. aureus (0.78 mg/ml). Aqueous and ethanol extracts of H. caffrum bark were active against both Gram-positive and Gram-negative bacteria. Hypoxis latifolia aqueous corm extracts exhibited very good MIC values against K. pneumoniae (0.78 mg/ml), E. coli and S. aureus (1.56 mg/ml). Ethanol and ethyl acetate bulb extracts of Ledebouria ovatifolia displayed good activity against Bacillus subtilis bacteria with MIC values of 0.78 mg/ml and 0.39 mg/ml respectively. Antifungal activity was evaluated using the microdilution bioassay. Good activity was shown by the ethanolic bark extracts of Bersama lucens and Harpephyllum caffrum against Candida albicans. Only in the case of Harpephyllum caffrum did aqueous extracts have activity against Candida albicans. In the Ames test, all plant extracts showed a negative genotoxic response except for ethanol and ethyl acetate bulb extracts of Cyrtanthus obliquus which induced mutations in TA98. Moderate antimutagenic activity was observed with the ethyl acetate extract of G. perpensa and the ethanolic extract of H. latifolia. High antibacterial and antifungal activity detected with Harpephyllum caffrum bark extracts resulted in an investigation on seasonal and geographical variation of this inhibitory activity. Seasonal variation in antibacterial and antifungal activities was investigated in order to determine the best collection time to ensure potential high medicinal activity in plant preparations. The highest inhibitory activity was detected with plant material collected in June and December 2003, with a decline in activity when collections were made in September 2004. The chemical profiles of TLC chromatograms were compared and little variation was found, particularly in the case of plant material obtained from the Botanic Garden of the University of KwaZulu-Natal and a 'Muthi' Shop in Pietermaritzburg. Identification of active compounds from G. perpensa and H. caffrum was not successful due to insufficient amounts of isolated fractions. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2006.

Petroleum ether, dichloromethane, and 80% ethanol extracts of 15 plant species collected in Nigeria were screened for in vitro antibacterial, anti-inflammatory and antimalarial activities. Antibacterial activity was tested using the agar diffusion method, while the minimum inhibitory concentrations (MIC) of the active extracts were determined using the microtitre serial dilution method. Most antibacterial activity detected was against Gram-positive bacteria with Staphylococcus aureus being the most susceptible. The highest activity was found in petroleum ether and dichloromethane leaf extracts of Mallotus oppositifolius; petroleum ether, dichloromethane and ethanolic root extracts of Newbouldia laevis; and ethanolic root extracts of Morinda lucida and Canthium subcordatum. Against the Gram-negative bacterium Escherichia coli, the highest activity was found in dichloromethane leaf extracts of Newbouldia laevis, ethanolic root extracts of Phyllanthus amarus, Mallotus oppositifolius, and Canthium subcordatum. A total of 60 plant extracts were screened for antiplasmodial activity. A chloroquine sensitive strain of Plasmodium falciparum (D10) was used. In the assay, the parasite lactate dehydrogenase (pLDH) activity was used to measure parasite viability. About 11 extracts showed promising activity with an IC₅₀ ranging from 2.5 to 13.4 µg/ml. The petroleum ether leaf extract of Hyptis suaveolens had the highest activity (IC₅₀ = 2.5 µg/ml). The cyclooxygenase (COX-1 and COX-2) assays were used to test for anti-inflammatory activity. All the plant species, with the exception of Hedranthera barteri and Picralima nitida showed anti-inflammatory activity. Apart for a few ethanolic extracts, all the activities were recorded with petroleum ether and dichloromethane extracts. Employing bioassay-guided activity fractionation, an antibacterial anthraquinone identified as emodin was isolated from ethanolic root extract of Senna occidentalis. Although this compound had been isolated from other sources, this was the first report of isolation from Senna occidentalis. Using a similar approach a novel antimalarial diterpenoid was isolated from the petroleum ether leaves extract of Hyptis suaveolens. It had IC₅₀ of 0.1 µg/ml. This new compound is worthy of further investigation and may act as an important lead compound for future antimalarial drugs. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2005.

Among all the major infectious human diseases, gastro-intestinal infections caused by microbial pathogens are a major cause of morbidity and infant death in developing countries, largely due to inadequate sewage disposal and contaminated water. Traditional health practitioners in South Africa play a crucial role in providing health care to the majority of the population. Many plants are locally used by South African traditional healers to treat microbial infections related to gastro-intestinal tracts. Ethnopharmacological and ethnobotanical studies using traditional knowledge as a selection strategy has given priority to certain plants for isolation and identification of plant novel bioactive compounds. Pharmacological and phytochemical studies of the investigated twelve medicinal plant species (from 10 families) extensively used as antimicrobials against gastro-intestinal infections was necessary to validate the use of the plants. Furthermore, to provide sufficient preliminary information for the isolation and identification of active compounds that are present in the investigated plants. Plant parts were sequentially extracted using petroleum ether (PE), dichloromethane (DCM) and 70% ethanol (EtOH). Cold water and boiled (decoction) extracts of the plant materials were prepared non- sequentially. Among the extracts, EtOH yielded the highest amount of plant substances. A total number of 85 extracts were evaluated for antibacterial activity, 80 for antifungal activity, 64 for anti-inflammatory activity, and 27 biologically active extracts were tested for genotoxicity. The microdilution method was used to determine the minimum inhibitory concentration values in the antibacterial assay against two Gram-negative bacteria (Escherichia coli ATCC 11775 and Klebsiella pneumoniae ATCC 13883) and two Gram-positive bacteria (Bacillus subtilis ATCC 6051 and Staphylococcus aureus ATCC 12600). A modified microdilution method was used to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values in the antifungal assay against Candida albicans. Cyclooxygenase assay was used to evaluate the anti-inflammatory activity of the extracts against cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes. The plant extracts were screened first at a concentration of 250 ƒÊg/ml per test sample, and then further screened at concentrations of 125 and 62.5 ƒÊg/ml for extracts that inhibited the COX-2 enzyme. The Ames test was used to test for genotoxicity in extracts that showed interesting pharmacological activities using Salmonella typhimurium strain TA98. Among the screened extracts, 25 extracts showed good antibacterial activity with MIC values . 1.0 mg/ml. Dichloromethane extracts exhibited the greatest antibacterial activity, and Gram-positive bacteria were most susceptible. The best antibacterial activity was exhibited by Becium obovatum leaf EtOH extracts with an MIC value of 0.074 mg/ml. A broad spectrum antibacterial activity was observed by leaf extracts of Cucumis hirsutus (PE), Haworthia limifolia (PE), Protea simplex (PE and DCM) and Dissotis princeps (EtOH) against both Gram-negative and Gram-positive bacteria. No interesting antibacterial activity was exhibited by water extracts with the exception of Dissotis princeps water extract with a good antibacterial activity against Gram-positive and Gram-negative bacteria. In the antifungal assay, 6 extracts showed interesting antifungal activity. Protea simplex leaf PE extract showed the best fungicidal activity with an MFC value of 0.014 mg/ml. The best overall antifungal activity was observed in plant EtOH extracts. Some extracts from Agapanthus campanulatus (leaves and roots), Dissotis princeps (leaves), Gladiolus dalenii (corms) and Protea simplex (leaves) showed good activity against Candida albicans. Twenty one extracts inhibited the COX-1 enzyme, while fifteen extracts inhibited the COX-2 enzyme at the lowest screening concentration of 62.5 ƒÊg/ml. The highest COX-1 inhibition at a concentration of 62.5 ƒÊg/ml was exhibited by Diospyros lycioides leaf PE extract (89.1%) while Agapanthus campanulatus root DCM extract showed the highest COX-2 inhibitory activity (83.7%) at the same concentration. In the Ames test, no genotoxicity was observed in any of the extracts, however more tests need to be done to confirm these results. Thin layer chromatograms of the organic solvent plant extracts were developed. The fingerprints of the plant extracts showed colours of bands at different Rf values when viewed under UV254 and UV366 suggesting that the investigated plant species contained different compounds in the extracts. In the quest to understand the source of the plants pharmacological activities, total phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively investigated in terms of their amounts in the aqueous methanol extracts of the plants materials using spectrophotometric methods. Alkaloids and saponins were qualitatively determined. The amounts of total phenolics were determined by the Folin Ciocalteu assay, condensed tannins were determined by the butanol-HCl assay, while rhodanine and vanillin assays were used to determine the amounts of gallotannins and flavonoids respectively. Dragendorff reagent was used to detect alkaloids in the plant extracts on thin layer chromatographic plates, while the froth test was employed to detect saponins. Secondary metabolites varied with plant parts and species with Cyperus textilis (leaf) having the highest amounts of total phenolics, condensed tannins and flavonoids. The highest amount of gallotannins was detected in Protea simplex leaf extracts. All the investigated plant materials with the exception of Haworthia limifolia leaf, Protea simplex leaf, Antidesma venosum leaf and Dissotis princeps leaf tested positively to saponins. Alkaloids were detected in Haworthia limifolia leaf (PE and EtOH), Cucumis hirsutus leaf (EtOH), Becium obovatum root (DCM), Protea simplex root and bark (EtOH), Agapanthus campanulatus root (DCM) and leaf (EtOH), Cyperus textilis root (DCM), Vernonia natalensis leaf (PE), Antidesma venosum leaf (PE), Diospyros lycioides leaf (PE) and Dissotis princeps leaf (DCM) extracts. The results obtained from the investigation of the pharmacology and phytochemistry of the plant species used to treat microbial infections related to gastro-intestinal tracts, provide sufficient preliminary information to validate the use of some of the plants in traditional medicine. The information provided might be considered sufficient for further studies aimed at isolating and identifying the active compounds in the plant species, and evaluating possible synergism amongst the isolated compounds. / Thesis (M.Sc)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Diarrhoea and related diseases are the most common causes of death in children, especially from developing countries, killing about 1.5 million children under the age of five yearly. In South Africa, diarrhoea is the third leading cause of death. This condition results from food and water sources infected with Campylobacter spp., Escherichia coli, Salmonella spp., Shigella spp., Giardia intestinalis and Cryptospondium parvum amongst others. Diarrhoea spreads through faeces-contaminated water. Hence, infection is more common when there is a short supply of clean drinking and cooking water. Waterborne diseases are common in rural communities of Bizana because the majority of rural dwellers depend largely on water from unprotected sources. Most of the pathogens that cause diarrhoea have developed resistance to several antibiotics. Therefore there is a need for new and safe antidiarrhoeal drugs. Most people in developing countries use traditional medicine to treat all kinds of diseases including diarrhoea and South Africa is no exception. Each cultural group in South Africa has different medical solutions for the prevention and curing of the same disease. The people from Pondoland (AmaMpondo), around Bizana have a strong tradition of using medicinal plants for the cure and prevention of several conditions including diarrhoea. Although several researchers have conducted different types of studies in many parts of South Africa to evaluate the efficacy of traditional medicine used in the treatment of diarrhoea, there is, however, still a lot of undisclosed data that should be collected. The aims of this research were to record and collect medicinal plants that are used for treating diarrhoea in Bizana, Pondoland in the Eastern Cape and evaluate them for their pharmacological properties. An ethnobotanical approach is one of several methods that have been useful in selecting plants for pharmacological research, yielding better results than other plant selection methods. Using questionnaires, this approach was used to record plants that are used for treating diarrhoea in Bizana for testing in pharmacological assays. From the completed questionnaires, nine plants were selected for bioassays based on their higher frequency index, and the fact that the plants have never been evaluated against diarrhoea causing-microorganisms. The study revealed 34 plant species belonging to 21 families as being used in treatment of diarrhoea in the study area. Psidium guajava was the most mentioned plant species. The dried, ground plant materials were each extracted non-sequentially using petroleum ether (PE), dichloromethane (DCM), 70% ethanol (EtOH) and water. Among all the extracts, 70% ethanol yielded the highest quantity of crude extract. The extracts were each evaluated for their antibacterial, anti-inflammatory and genotoxicity properties. For the antibacterial activity, the following diarrhoea causing microorganisms were used: Gram-positive Staphylococcus aureus and Gram-negative Campylobacter jejuni, E. coli and Shigella flexneri. A microdilution assay (for S. aureus, E. coli and S. flexneri) and the disk diffusion technique (for C. jejuni) were used for antibacterial testing. The extracts were also evaluated for their ability to inhibit cyclooxygenase (COX-1 and -2) enzymes. Genotoxicity was evaluated using the Salmonella microsome assay without S9 metabolic activation. Three strains of Salmonella typhimurium TA98, TA1535 and TA1537 were used. The evaluated plant extracts showed a broad spectrum of inhibitory activity with MIC values ranging from 0.098-12.5 mg/ml and mean zone inhibition percentage ranging from 0-73%. The best activity was exhibited by DCM extracts of Rapanea melanophloeos, EtOH extracts of Ficus craterostoma and Maesa lanceolata with MIC values of 0.098 mg/ml and EtOH extracts of Searsia chirindensis with 73% mean zone inhibition percentage. The inhibitory activity against COX-1 enzyme was higher than COX-2, with 19 plant extracts for the former and 7 for the latter. The highest inhibition of COX-1 was shown by EtOH extracts of F. craterostoma and the DCM extract of S. chirindensis at 100%. Highest percentage COX-2 inhibition was shown by water extracts of F. craterostoma and DCM extracts of Tecoma capensis with 99.5% and 99.0% respectively. None of the tested plant extracts were mutagenic, at all concentrations tested against all tester strains of the bacteria. The results of this study demonstrate that people still have a rich and diverse pool of knowledge concerning the uses of plants against diarrhoea. The data also show that plants form part of the cultural heritage of the communities in Pondoland. Therefore it is important to urgently save the people’s cultural heritage by recording the existing knowledge and confirming therapeutic uses of plants through scientific methods. This will prevent the information from vanishing together with the ageing knowledge holders. In light of the fact that the evaluated plants were selected based on their ethnobotanical use for treating diarrhoea, the activities reported here goes a long way in adding value to the plants used as part of traditional medicine. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

La situation épidémiologique des maladies infectieuses et parasitaires a eu un impact considérable sur de nombreux changements globaux importants. Ce type de maladies offre continuellement, encore aujourd’hui, de nouveaux défis à la recherche scientifique ; on peut notamment citer l’épidémie du virus ebola, responsable de plus de 11 000 morts en 2015, l'émergence du virus zika au Brésil, les cas de schistosomiase en Corse en 2014, en plus des différents cas d'exposition des patients dans les zones endémiques des pays tropicaux. L’émergence rapide de nombreuses épidémies est notamment due à certains changements sociaux observés au niveau global depuis quelques décennies, caractérisés entre autre par une urbanisation rapide et une communication facilitée entre les continents. Ces différents facteurs ont par conséquent contribué à la conception du profil épidémiologique des maladies infectieuses et parasitaires dans le monde entier. Parmi ces maladies, la schistosomiase est une maladie parasitaire grave causée par trématode Schistosoma mansoni. Actuellement, le praziquantel (PZQ) est le seul médicament capable de traiter toutes les différentes formes de la schistosomiase. Néanmoins, une nouvelle classe de molécule, les imidazolidines, hétérocycles pentagonaux possédants diverses activités biologiques, se sont également révélés actifs contre les Schistosoma. Le premier objectif de cette étude sera donc de déterminer l'activité schistosomicide de nouveaux dérivés thioxo-imidazolidínicos. Dans ce contexte, 24 nouveaux composés 5-arylidène-3-(2-chloro,6-fluoro)-benzyl-2-thioxo-imidazolidin-4-one (PTS) ont été obtenus. Après analyse en composantes principales (ACP), les 11 dérivé les plus (dis)-similaires ont été évalués biologiquement. L’un d’eux, le dérivé indole-imidazolidine LPSF-PTS-14, a montré des résultats supérieurs à la PZQ. En effet, la mort de 100% des vers a été observée après 24 heures à une concentration de 5 g/ml de ce composé, ainsi qu’une cytotoxicité inférieure à 5 ug/ml pour des cellules humaines. Ces résultats ont stimulé le développement d'un modèle de pharmacophore en utilisant le logiciel FLAP. Une évaluation sur le mode d’action de la molécule, ainsi que le développement d’un modèle de prédiction sur la cytotoxicité de ces composés, ont également été développés. Le deuxième objectif portait sur la réalisation d'une étude bibliographique sur le PZQ, permettant d’amener une proposition de modèle sur la relation structure-activité entre les composés chimiques actifs et leur activité biologique. Ensuite, dans une partie qui présente des travaux encore en cours, a été abordé un modèle de pharmacophore et de prédiction d'activité par les méthodes chimiométriques. En ce qui concerne l'infection bactérienne, l'apparition de super bactéries comme par exemple une souche d’Escherichia coli résistante à tous les antibiotiques disponibles, a recentré l'attention sur le développement de nouveaux antibiotiques. Les aminoglycosides, comme la neamine, sont une famille de molécules d’origine naturelle ou semi-synthétique, efficaces contre les bactéries Gram (+) et Gram (-). Le dernier objectif de cette thèse était donc de réaliser la synthèse d'analogues de Neamina, un aminoglycosides, à partir de la N-acétyl-D-glucosamine par l'utilisation de réactions de métathèse. Bien que la synthèse de ces composés n’ai pas pu être menée jusqu’au bout, des progrès importants ont été réalisés sur les voies de synthèse proposées et certains intermédiaires clés ont été obtenus. Une évaluation de la compatibilité de certains groupes protecteurs avec les conditions de métathèse utilisées a également été réalisée, permettant ainsi de proposer une nouvelle voie de synthèse, entamée dans ce travail, mais qui devra être achevée par la suite. / The epidemiological situation of infectious and parasitic diseases has presented significant changes worldwide. This group of diseases continues to pose challenges to prevention programs, such as the ebola virus epidemic, which is responsible for more than 11,000 deaths in 2015, the emergence of the zika virus in Brazil, the cases of schistosomiasis in the region of Corsica, France, in 2014, not including the exposure of patients to endemic areas in tropical countries. This scenario reflects the social transformations that have occurred in the last decades, characterized by accelerated urbanization, communication between continents, among other factors that contributed to the delineation of the current epidemiological profile of infectious and parasitic diseases worldwide. Schistosomiasis mansoni is a severe parasitosis caused by the Schistosoma mansoni trematode. Currently, praziquantel (PZQ) is the only drug capable of treating all the different forms of schistosomiasis. The imidazolidines are represented by a group of pentagonal heterocyclic substances possessing diverse biological activities, among them the schistosomicidal activity. The first objective of this work is the investigation of the schistosomicidal activity of new thioxoimidazolidine derivatives. In this context, 24 new arylidene-3-(2-chloro, 6-fluoro)-benzyl-imidazolidin-2-thioxo-4-one derivatives of (PTS) were obtained. After principal component analysis (PCA), the most dissimilar derivatives were evaluated biologically. The indolyl-imidazolidinic derivative, LPSF / PTS-14, presented greater results than PZQ, 100% death of worms in 24 h at 5 μg / mL, and a toxicity below 5 μg / mL against BALB splenocytes / C mice. These results, combined with low cytotoxicity, stimulated the development of a pharmacophor model using FLAP software, as well as the evaluation of the mode of action by the Michael Addition reaction, and the development of a prediction model for cytotoxicity. The second objective of this work was the accomplishment of a bibliographic study about the PZQ, making it possible to propose a model relating chemical structure and biological activity. Then, in works still under development, a model of pharmacophores will be proposed, and prediction of activity through chemometric methods made. In relation to bacterial infections, the appearance of superbugs, such as the Escherichia coli strain resistant to all antibiotics available in the clinic in 2016, again calls attention to the development of new antibiotics. Aminoglycosides, such as Neamine, are a family of substances of natural or semi-synthetic origin that are effective against Gram (+) and Gram (-) bacteria. The third objective of this work was the synthesis of analogues of Neamine from N- Acetyl-D-glucosamine and the use of metathesis reactions. Although none of the proposed derivatives were synthesized in the allotted time, important advances were made in the proposed routes, and key intermediaries were obtained. It was also possible to develop an evaluation study between the compatibility of protective groups used in derivatives and the occurrence of metathesis reactions. These studies led to the proposition of a synthetic route compatible with the protective groups, initiated at the end of this work, and to be concluded in the future.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Historicamente, as bactÃrias foram vistas como organismos que vivem isolados, no entanto, à claro, agora, que a grande maioria de bactÃrias existe em comunidades complexas, conhecidas como biofilmes. As bactÃrias em biofilmes se encontram aderidas a superfÃcies diversas, tanto abiÃticas como biÃticas (dente, osso, mucosa), compondo um ecossistema altamente estruturado, dinÃmico e organizado. Um exemplo de infecÃÃo que pode envolver a presenÃa formaÃÃo de biofilme à a otite - definida como inflamaÃÃo aguda ou crÃnica da orelha, podendo se estender desde o epitÃlio do conduto auditivo externo atà a orelha interna. Descrita como a doenÃa mais comum do canal auditivo externo em cÃes, possui uma etiologia multifatorial, que inclui fungos e bactÃrias, principalmente do gÃnero Staphylococcus. BactÃrias desse gÃnero sÃo comensais de pele e mucosas, mas podem atuar como patÃgenos oportunistas em condiÃÃes propÃcias e sÃo frequentemente associadas a uma ampla variedade de infecÃÃes em seres humanos e animais com vÃrios relatos de refratariedade aos tratamentos usuais. Em um biofilme, as bactÃrias podem ser dezenas de vezes mais resistentes aos antibiÃticos, quando comparadas Ãs mesmas bactÃrias em crescimento planctÃnico. O combate a infecÃÃes envolvendo bactÃrias em biofilme à um grande desafio da microbiologia mundial, que leva à busca de novas opÃÃes terapÃuticas. Com efeito, este estudo teve como objetivo avaliar o efeito inibitÃrio in vitro de seis substÃncias â trÃs agentes antimicrobianos clÃssicos, ciprofloxacina, cloranfenicol, gentamicina; e trÃs agentes antimicrobianos nÃo-clÃssicos timol, carvacrol, perÃxido de hidrogÃnio (H2O2) â contra cepas estafilocÃcicas de otite canina em crescimento planctÃnico e em biofilme. Foram avaliadas 54 cepas clÃnicas isoladas de secreÃÃo purulenta de cÃes com otite, divididas entre cinco espÃcies: S. intermedius, S. simulans, S. haemolyticus, S. epidermidis e S. lugdunensis. As 16 cepas classificadas como produtoras de biofilme (11 de S. intermedius e cinco de S. simulans), segundo resultado obtido pelo teste do Ãgar vermelho Congo e confirmaÃÃo por microscopia eletrÃnica de varredura (MEV), foram usadas em ensaios de microdiluiÃÃo em caldo para determinaÃÃo de concentraÃÃo inibitÃria mÃnima (CIM) e concentraÃÃo inibitÃria mÃnima em biofilme (CIMB). Com relaÃÃo Ãs cepas produtoras de biofilme, foram observados os seguintes resultados: os valores para ciprofloxacina foram 0,12 &#8804;CIM&#8804;0,5 mcg/mL (mÃdia 0,28 mcg/mL) e 0,5&#8804;CIMB&#8804;8 mcg/mL (mÃdia 1,79 mcg/mL); para cloranfenicol 2&#8804;CIM&#8804;16 mcg/mL (mÃdia 7,41 mcg/mL) e 8&#8804;CIMB&#8804;32 mcg/mL (mÃdia 20,71 mcg/mL); para gentamicina 0,5&#8804;CIM&#8804;4 mcg/mL (mÃdia 2,09 mcg/mL) e 4&#8804;CIMB&#8804;64 mcg/mL (mÃdia 24,24 mcg/mL); para timol 32&#8804;CIM&#8804;512 mcg/mL (mÃdia 137,41 mcg/mL) e 256&#8804;CIMB&#8804;2048 mcg/mL (mÃdia 768 mcg/mL); carvacrol 32&#8804;CIM&#8804;512 mcg/mL (mÃdia 128 mcg/mL) e 256&#8804;CIMB&#8804;4096 mcg/mL (mÃdia 993,88 mcg/mL); e para H2O2 32&#8804;CIM&#8804;128 ppm (mÃdia 99,76 ppm) e 128&#8804;CIMB&#8804;4096 ppm (mÃdia 1874,82 ppm). Os dados obtidos apontam para o potencial terapÃutico dos seis antibiÃticos estudados no tratamento de infecÃÃes estafilocÃcicas associadas a biofilme, sendo necessÃrios novos estudos para investigar os mecanismos de aÃÃo dessas drogas sobre o biofilme, bem como o delineamento de experimentos in vivo para confirmar a significÃncia desses achados. / Historically, bacteria have been seen as isolated organisms; however, it is now clear that the vast majority of bacteria exist in complex communities known as biofilms. Bacteria in biofilms are adhered to various surfaces, both abiotic and biotic (teeth, bones, mucosa), often forming a highly dynamic ecosystem, which is structured and organized. An example of infection, which can involve the formation of biofilm is otitis - defined as an acute or chronic inflammation of the ear, which may extend from the external ear canal to the inner ear. Described as the most common disease of the external ear canal in dogs, it has a multifactorial etiology, including fungi and bacteria, especially of the genus Staphylococcus. Bacteria of this genus are commensal to skin and mucous membranes, but can act as opportunistic pathogens in favorable conditions and are often associated with a wide variety of infections in humans and animals with many reports of refractoriness to usual treatments. In biofilm, bacteria can be ten to a hundred times more resistant to antibiotics when compared to the same bacteria in planktonic growth. The struggle to fight infections involving bacterial biofilms is a major challenge of microbiology today, which, in turn, leads to the search for new therapeutic options. Thus, this study aimed to evaluate the in vitro inhibitory effect of six substances â three classic antimicrobial agents ciprofloxacin, chloramphenicol, gentamicin; and three non-classic antimicrobial agents thymol, carvacrol, hydrogen peroxide (H2O2) - against staphylococcal strains from canine otitis in planktonic growth and in biofilm. We analyzed 54 clinical strains isolated from purulent secretion of canine otitis, divided into five species: S. intermedius, S. simulans, S. haemolyticus, S.epidermidis and S. lugdunensis. The 16 strains classified as biofilm producers (11 S. intermedius and five S. simulans), according to result obtained by the Congo red agar test and confirmed by scanning electron microscopy (SEM), were used in broth microdilution assay for determination of minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC). With regards to the biofilm-producing strains, the following results were observed: the values for ciprofloxacin were 0,12 &#8804;MIC&#8804;0,5 mcg/mL (mean 0,28 mcg/mL) and 0,5&#8804;MBIC&#8804;8 mcg/mL (mean 1,79 mcg/mL); for chloramphenicol 2&#8804;MIC&#8804;16 mcg/mL (mean 7,41 mcg/mL) and 8&#8804;MBIC&#8804;32 mcg/mL (mean 20,71 mcg/mL); for gentamicin 0,5&#8804;MIC&#8804;4 mcg/mL (mean 2,09 mcg/mL) and 4&#8804;MBIC&#8804;64 mcg/mL (mean 24,24 mcg/mL); for thymol 32&#8804;MIC&#8804;512 mcg/mL (mean 137,41 mcg/mL) and 256&#8804;MBIC&#8804;2048 mcg/mL (mean 768 mcg/mL); carvacrol 32&#8804;MIC&#8804;512 mcg/mL (mean 128 mcg/mL) and 256&#8804;MBIC&#8804;4096 mcg/mL (mean 993,88 mcg/mL); and for H2O2 for 32&#8804;MIC&#8804;128 mcg/mL (mean 99,76 ppm) and 128&#8804;MBIC&#8804;4096 ppm (mean 1874,82 ppm). The presented data indicates the therapeutic potential of the six antibiotics studied in the treatment of staphylococcal infections associated with biofilm, which warrants further studies to investigate the mechanisms of action of these drugs on biofilms and the design of in vivo experiments to confirm the significance of these findings.