Inibição do crescimento de Escherichia coli isolada de Queijo Minas Frescal por Lactobacillus acidophilus

Escherichia coli faz parte da microbiota anaeróbica facultativa normal, sendo também considerada um dos maiores patógenos entéricos predominantes no cólon dos animais e homem. Neste trabalho, realizaram-se ensaios in vitro para avaliar o grau de atividade antagonista de cinco cepas de Lactobacillus acidophilus, com capacidade probiótica sobre Escherichia coli BIA 26 (STEC) isolada de queijo Minas Frescal. Para tanto, foi utilizado o teste de inibição através do método de dupla camada em triplicata para avaliar zonas de inibição de crescimento. Todas as cepas de Lactobacillus mostraram-se capazes de inibir a E. coli, com zonas de inibição variando de 12 a 15mm de diâmetro, sendo que a maioria apresentou 14mm de diâmetro, consideradas como fortes halos de inibição.

Colonisation of soft lining materials by micro-organisms

Objective:This study evaluated the in vitro adherence of pathogenic micro-organisms, Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa, to soft lining materials and their inhibitory effect on these micro-organisms.Materials and Methods:To measure adherence, specimens of Molloplast B and Ufi Gel P were inoculated [107 colony-forming units per millimetre (cfu/ml)] with TSB media containing the micro-organisms. To determine the number of micro-organisms in the 10-2-10-5 dilutions, 25 mu l of the suspension were transferred to plates of selective media. Colony counts of each specimen were quantified (cfu/ml). The surface roughness was measured with a perfilometer to assess the relationship between the adherence of micro-organisms and surface roughness of each material. For the inhibition test, specimens of materials were placed in agar plates inoculated individually with the micro-organisms. After 48 h, the inhibition zones around the specimens were measured.Results:None of the materials exhibited inhibition zones. The number of cfu/ml of S. aureus and P. aeruginosa were significantly greater than C. albicans for both materials. The Ufi Gel P exhibited greater adherence of C. albicans than Molloplast B. No correlation was observed between the adherence of micro-organisms and surface roughness.Conclusion:The surface roughness of the materials is not the only factor governing micro-organism adherence.

Direct and transdentinal antibacterial activity of chlorhexidine

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Antimicrobial activity of disinfectant agents incorporated into type IV dental stone

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antimicrobial activity of 2% chlorhexidine gluconate, 1% sodium hypochlorite and paramonochlorophenol combined with furacin against S. aureus, C. albicans, E. faecalise and P. aureginosa

OBJETIVO: Analisar a ação antimicrobiana da clorexidina a 2%, do hipoclorito de sódio a 1% e do paramonoclorofenol associado ao furacin sobre S aureus, C albicans, E faecalise e P aureginosa. METODOLOGIA: Foram utilizadas 40 placas Petri. Quatro placas foram separadas como controle negativo e em 4 outras, além do meio de cultura, semearam-se os microrganismos, com o círculo de papel, para se obter o controle positivo. em 32 placas seguiu-se a colocação de 4 círculos de filtro de papel esterilizados e impregnados das substâncias testes e controle, depositados em cada quadrante das mesmas. Os grupos foram analisados por 7 dias. Para a verificação dos resultados, usaram-se os halos de inibição de crescimento bacteriano. RESULTADOS: A clorexidina 2% foi significantemente (P<0,05) mais efetiva para todas as cepas microbianas que as demais substâncias. O hipoclorito de sódio a 1% apresentou resultados intermediários. O paramonoclorofenol associado ao furacin (PMC+F) obteve os piores resultados. CONCLUSÃO: A clorexidina obteve os melhores resultados. O PMC+F apresentou os menores halos de inibição.

Microbial leakage of MTA, Portland cement, Sealapex and zinc oxide-eugenol as root-end filling materials

Objective: The aim of this study was to compare the microbial leakage of mineral trioxide aggregate (MTA), Portland cement (PC), Sealapex and zinc oxide-eugenol (ZOE) as root-end filling materials.Study design: An in vitro microbial leakage test (MLT) with a split chamber was used in this study. A mixture of facultative bacteria and one yeast (S. aureus + E. faecalis + P. aeruginosa + B. subtilis + C. albicans) was placed in the upper chamber and it could only reach the lower chamber containing Brain Heart Infusion broth by way of leakage through the root-end filling. Microbial leakage was observed daily for 60 days. Sixty maxillary anterior human teeth were randomly assigned to different groups - MTA and PC (gray and white), Sealapex + zinc oxide and ZOE, control groups and subgroups to evaluate the influence of EDTA for smear layer removal. These materials were further evaluated by an agar diffusion test (ADT) to verify their antimicrobial efficacy. Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney test.Results: In the MLT, Sealapex + zinc oxide and ZOE did not show evidence of microbial leakage over the 60-day experimental period. The other materials showed leakage from the 15th day. The presence of smear layer influenced microbial leakage. Microbial inhibition zones were not observed in all samples tested by ADT.Conclusion: Sealapex + zinc oxide and ZOE did not show microbial leakage over the experimental period, whereas it was verified within 15 to 45 days in MTA and Portland cement.

Residual antibacterial activity of chlorhexidine digluconate and camphorated p-monochlorophenol in calcium hydroxide-based root canal dressings

The purpose of this study was to evaluate the residual antibacterial activity of several calcium hydroxide [Ca(OH) 2]-based pastes, placed in root canals of dogs' teeth with induced chronic periapical lesions. Root canals were instrumented with the ProFile rotary system and filled with 4 pastes: G1 (n=16): Ca(OH) 2 paste + anesthetic solution; G2 (n=20): Calen® paste + camphorated pmonochlorophenol (CMCP); G3 (n=18): Calen®; and G4 (n=18): Ca(OH) 2 paste + 2% chlorhexidine digluconate. After 21 days, the pastes were removed with size 60 K-files and placed on Petri plates with agar inoculated with Micrococcus luteus ATCC 9341. Pastes that were not placed into root canals served as control. After pre-diffusion, incubation and optimization, the inhibition zones of bacterial growth were measured and analyzed by Mann-Whitney U test at 5% significance level. All pastes showed residual antibacterial activity. The control samples had larger halos (p<0.05). The mean residual antibacterial activity halos in G1, G2, G3 and G4 were 7.6; 10.4; 17.7 and 21.4 mm, respectively. The zones of bacterial growth of G4 were significantly larger than those of G1 and G2 (p<0.05). In conclusion, regardless of the vehicle and antiseptic, all Ca(OH) 2-based pastes showed different degrees of measurable residual antibacterial activity. Furthermore, unlike CMCP, chlorhexidine increased significantly the antibacterial activity of Ca(OH) 2.

Atividade viral do vírus respiratório sincicial bovino (brsv) em bezerros leiteiros

The purpose of the present study was to evaluate the antimicrobial activity of propolis extracts diluted in different solvents against bacteria from Staphylococcus genus. The study was performed in the Immunology and Microbiology Laboratory from Universidade Federal do Vale do São Francisco. The propolis extracts were prepared using brown propolis diluted in different solvents such as chloroform, methanol, ethyl acetate and grain alcohol. In order to determine the antimicrobial potential of extracts, agar well diffusion method was used, with controls for each diluent. After that, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods were used. All tests were performed in triplicate. In the agar well diffusion test, the measurements of the inhibition zone for propolis extract were as follows: grain alcohol and propolis (2.88mm), methanol and propolis (2.41mm), chloroform and propolis (2.40mm) and ethyl acetate and propolis (0.83mm). The MBC of propolis extracts in different solvents were 93.75 μg/mL for grain alcohol, 375 μg/mL for chloroform and methanol and 3,000 μg/ml for ethyl acetate. Statistically significant differences were achieved comparing the inhibition zones of propolis diluted in grain alcohol and ethyl acetate (2.88 and 0.83 mm, respectively). Considering the low cost of therapy and the activity of the propolis against caprine mastitis pathogens, other studies regarding in vivo activity and chemical characterization are necessary, in addition to evaluation of the toxicological aspects of propolis extracts.

Antibacterial activity of oregano essential oil against foodborne pathogens

Purpose: This paper aims to evaluate in vitro antibacterial activity of oregano essential oil against foodborne pathogens as a starting point for the use of spice as a natural preservative in food. Design/methodology/approach: Disc and well-diffusion assays were performed to investigate antibacterial activity of oregano essential oil against six bacteria strains: Bacillus cereus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella Typhimurium. Three concentrations of oregano essential oil were employed: 1.0 percent, 2.0 percent and 5.0 percent. Bacterial growth inhibition was determinate as the diameter of the inhibition zones. Findings: Oregano essential oil showed antibacterial activity against spoilage microorganisms, at different concentrations, except for P. aeruginosa. There was a significant difference between methodologies only for the microorganism S. aureus. The results provided evidence of the existence of significant differences among the concentrations of oregano essential oil for each microorganism evaluated. Research limitations/implications: Although the research for this paper involved only oregano essential oil, it provided a starting-point for further investigations concerning spices as natural preservatives for food systems. Practical implications: Disc and well-assays were found to be simple and reproducible practical methods. Other spices, their essential oil and extracts might be researched against other micro-organisms. Furthermore, in situ studies need to be performed to evaluate possible interactions between essential oils and compounds naturally present in food against microbial strains. Social implications: The imminent adoption of measures to reduce the use of additives in foods and the reduction on using such compounds. Originality/value: This study provides insights that suggest a promising exploratory development of food natural preservative against spoilage microorganisms in food systems by the use of oregano essential oil. © Emerald Group Publishing Limited.

Avaliação, in vitro, da atividade antibacteriana, liberação de fluoreto e capacidade de recarga de cimentos de ionômero de vidro para base forradora

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da atividade inibitória In vitro de bacteriocinas extraídas de Lactobacillus spp. isolados de aves (Gallus gallus, Linnaeus, 1758)

Pós-graduação em Medicina Veterinária - FMVZ

Rhizospheric streptomycetes as potential biocontrol agents of Fusarium and Armillaria pine rot and as PGPR for Pinus taeda

Pinus taeda is one of the main timber trees in Brazil, occupying 1.8 million ha with an annual productivity of 25-30 m(3) ha(-1). Another important species is Araucaria angustifolia, belonging to the fragile Rainforest biome, which for decades has been a major source of timber in Brazil. Some diseases that affect the roots and/or the stem of these trees and cause "damping-off" of the seedlings, with economic and environmental losses for the forest sector, are caused by the plant pathogenic fungi Fusarium sp. or Armillaria sp. This research project intended to isolate actinobacteria from the Araucaria rhizosphere, which present an antagonistic effect against these fungi. After the selection of the best pathogen inhibitors, morphologic characteristics, enzyme production, and their effect on the growth of Pinus taeda were studied. The actinobacteria were tested for their antagonistic capacity against Fusarium sp. in Petri plates with PDA as substrate. The inhibition zone was measured after 3, 5, 7, and 10 days. Of all the isolates tested, only two of them maintained inhibition zones up to 4 mm for 10 days. The inhibition of Armillaria sp. was tested in liquid medium and also in Petri dishes through the evaluation of the number of the fungal rhizomorphs in dual culture with the actinobacteria. It was found that all five isolates were able to inhibit the rhizomorph production, with the best performance of the isolate A43, which was capable of inhibiting both fungi, Fusarium and Armillaria. In a greenhouse experiment, the effect of five isolates on the growth of Pinus taeda seedlings was tested. Plant height, stem diameter, root and shoot dry matter were determined. The Streptomyces isolate A43 doubled plant growth. These results may lead to the development of new technologies in the identification of still unknown bacterial metabolites and new management techniques to control forest plant diseases.

Efeito antimicrobiano e citotóxico do óleo essencial de Cymbopogon citratus sobre células odontoblastóides

The aim of this study was to evaluate the antimicrobial and cytotoxic effect of essential oil (EO) of lemon grass (Cymbopogon citratus). From the agar diffusion method, different concentrations of EO (0.135%, 0.2% and 1%), and control solutions (chlorhexidine (Chx), distilled water (Ad) and cereal alcohol (Ac)) were applied on cultures of Candida albicans (C.a), Streptococcus mutans (S.m), Streptococcus sobrinus (S.sob) and Lactobacillus acidophilus (L.a). For C.a, S.m and S.sob, the largest inhibition zones in descending order were: Chx, Ac and EO 1%, while the latter two were statistically similar (Mann-Whitney, p> 0.05). For L.a, the largest inhibition halo was observed for the Chx, followed by EO at 1%, 0.2%, 0.135% and Ac. For evaluation of cytotoxicity, the following groups were set: G1: 0,1% EO; G2: pure EO; G3 (positive control): H2 O2 ; G4: cereal alcohol; and G5 (negative control): culture medium – DMEM. The solutions were applied on the cultured MDPC-23 cells, which were plated (30,000 cells/cm2 ) in wells of 24 well-dishes. Cell metabolism was evaluated by MTT assay. Considering G5 (negative control) as 100% of cell metabolism, it was observed for G1, G2, G3 and G4 a percentage reduction in cell metabolism of 29.6%, 82%, 81.2% and 33.4%, respectively. It was concluded that the low concentration of 0,1% OE (C. citratus) was able to inhibit the growth of the strains tested as well as caused mild cytotoxicity to the cultured MDPC-23 cells.

Desenvolvimento de um embutido cárneo fermentado, com teores reduzidos de gordura e sais de cura, através da utilização de culturas probióticas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anti-Helicobacter pylori activity and oxidative burst inhibition by the naphthoquinone 5-methoxy-3,4-dehydroxanthomegnin from Paepalanthus latipes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)