Navegando por Assunto "Bactérias patogênicas"

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Análise antimicrobiana de Enterococcus Spp. frente a microrganismos oportunistas do intestino
(2022-09-30) Silva, Paulo Henrique; Soares, Maria Taciana Cavalcanti Vieira; Brito, Leandro Paes de; http://lattes.cnpq.br/8176343095453312; http://lattes.cnpq.br/8174011112003131
Atualmente, há uma crescente busca por melhorias na qualidade de vida de seres humanos e animais através da utilização de probióticos, sendo este microrganismos vivos capazes de promover benefícios para a saúde, principalmente intestinal. Segundo órgãos oficiais, infecções intestinais são recorrentes, sendo responsável por milhares de mortes todos os anos. Sendo assim, optou-se pelo desenvolvimento de uma revisão sistemática e experimentos in vitro com o intuito de evidenciar uma eventual habilidadede bactérias do gênero Enterococcus frente a microrganismos oportunistas do intestino. A proposta de revisão sistemática teve como objetivo principal a verificação de uma possível capacidade antimicrobiana de Enterococcus frente a patógenos bacterianos a partir de estudos conduzidos em animais. Já para os experimentos in vitro, foi utilizado a bactéria ácido lática (BAL) Enterococcus faecium 133v com o intuito de verificar efeitos antagonista e antimicrobiano, bem como a utilização de Exopolissacarídeo (EPS) produzido por elas para fins de ação antibiofilme e antimicrobiana. Os artigos selecionados para revisão demonstram a capacidade de bactérias do gênero Enterococcus em inibir o crescimento de diversos patógenos de infecção intestinal, auxiliando na mitigação de danos no tecido tanto do intestino, como de outros órgãos. Além disso, foi possível observar diminuição ou exclusão de patógenos no trato intestinal e nas fezes dos animais, os quais apresentaram diminuição da perda de peso. Já os experimentos in vitro com E. faecium 133v frente a bactérias do gênero Shigella, Salmonella, Listeria e a espécie Escherichia coli, obteve resultados satisfatórios quanto à inibição desses patógenos. As análises antagonistas evidenciaram a capacidade da bactéria E. faecium 133v em contrapor 5 das 6 espécies patogênicas, com zona de inibição superior a 20mm. Outrossim, tanto o sobrenadante quanto o EPS de E. faecium 133v proporcionaram efeito antimicrobiana frente a todas as cepas. Ainda, o EPS foi eficiente em mitigar o desenvolvimento de biofilmes, comumente formados pelas 6 cepas patogênicas. Esses achados evidenciam a capacidade de algumas bactérias do gênero Enterococcus, bem como a espécie E. faecium 133v em contrapor as principais bactérias acarretadoras de infecção intestinal.
Atividade antibacteriana do óleo essencial de Croton tetradenius Baill frente a espécies de bactérias patogênicas
(2019) Silva, Maria Aliny Nathalia Almeida; Silva, Ana Luiza da; http://lattes.cnpq.br/4162831591004569; http://lattes.cnpq.br/1069558787287430
Medicinal plants of northeastern Caatinga are widely used in folk medicine by local communities, due to the therapeutic potential they present. Bacterial resistance to multiple drugs has increased in recently due to the indiscriminate use of antibiotics, generating the need for new broad spectrum drugs. Essential oils are known to be complex mixtures of volatile, lipophilic and odorous organic compounds that have numerous constituents due to secondary metabolites. This work aimed to evaluate the antimicrobial activity of Croton tetradenius (Euphorbiaceae) essential oil collected in the municipality of Triunfo-PE, obtained from the leaves by the hydrodistillation process. The evaluation was made by the paper disc diffusion method, in Petri plates, containing the MüellerHinton Agar medium, sown with bacterial suspensions previously adjusted to a 0.5 of the Mac Farland scale of three isolates. Discs containing 10 L and 15 L of the undiluted essential oil were added to the plates and incubated at 36 °C for 24 hours. Paper discs with the antibiotic Amikacin 30 μg/disc were used as positive control. The tests were performed in triplicates and the inhibition halos established in the average of the halos measured for each species of bacteria. The results show that Croton tetradenius essential oil has antimicrobial activity against the tested isolates Staphylococus aureus and Escherichia coli, except for Klebsiella pneumoniae which was resistant to the tested essential oil.
Atividade antimicrobiana de óleos essenciais de orégano (Origanum vulgare), pimenta rosa (Schinus terebinthifolia) e melaleuca (Melaleuca alternifólia) frente aos patógenos de origem alimentar
(2024-02-21) Silva, Esterfani Pereira da; Soares, Luciana Felizardo Pereira; http://lattes.cnpq.br/4071178363761831; http://lattes.cnpq.br/3144149210017027
In recent years, the use of synthetic additives to prevent food spoilage by microorganisms has been a worrying factor for the food industry, given their negative impact on consumer health. In order to overcome this impasse, essential oils have emerged as an alternative, containing compounds and active principles that inhibit the development of microorganisms. The aim of this study was to evaluate the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the commercially obtained essential oils of Tea tree (Melaleuca alternifolia), Oregano (Origanum vulgare) and Pink pepper (Schinus terebinthifolia). For the study, bacterial isolates at a concentration of 3.5 x 107 CFU/ml (0.5 on the Mc Farland scale) of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) obtained commercially from the American Type Culture Collection were used. The incubated plates were visually analyzed to determine the minimum inhibitory concentration (MIC). In the wells where inhibition of bacterial growth was observed, 20 μL of the suspensions were collected and sown on Mueller-Hinton agar plates in an oven at 37ºC for 24 hours to analyze bacterial growth and determine the minimum bactericidal concentration (MBC). The mean MIC values for oregano, pink pepper and tea tree essential oils were 2500 μg/ml, 650 μg/ml and 500 μg/ml for the E. coli strains, respectively, while the minimum inhibitory concentration of the treatments was 500 μg/ml for the S. aureus bacterial group. As far as CBM is concerned, the average concentrations for the essential oils of oregano, pink pepper and tea tree were 2500 μg/ml, 625 μg/ml and 5000 μg/ml for the E. coli strains and 1250 μg/ml, 2500 μg/ml and 625 μg/ml for the gram-positive bacteria S. aureus, respectively.
Determinação da taxa de sobrevivência de juvenis de Macrobrachium rosenbergii, experimentalmente infectados com Vibrio parahaemolyticus
(2023-08-15) Michereff, Gabriel Sobral; Silva, Suzianny Maria Bezerra Cabral da; http://lattes.cnpq.br/8569566022920336; http://lattes.cnpq.br/8665831491740543
Perfis genômicos do transposon Tn4401 de isolados de Proteus sp., Providencia sp. e Morganella sp
(2022-07-03) Silva, Larissa Almeida da; Freitas, Nara Suzy Aguiar de; Santos, Dayane da Silva; http://lattes.cnpq.br/0456504242112576; http://lattes.cnpq.br/6891650997818766
Antibiotic resistance is a growing global threat to public health, causing high mortality. Mutation, genetic drift, horizontal gene transfer via transposons, and natural selection are the basic mechanisms responsible for the spread of resistance genes among bacterial populations. The Proteeae tribe is composed of three genera: Proteus spp., Morganella spp. and Providencia spp., opportunistic pathogenic bacteria that are resistant to [beta]-lactams. The highly mobile transposon Tn4401 from Klebsiella pneumoniae and Escherichia coli is characterized by containing blaKPC genes encoding [beta]-lactamase, ensuring resistance to β-lactams. The objective was to analyze the evolutionary history of the genomes of the Proteeae tribe and its Tn4401 transposons, through patterns, variations and syntenies of genome sequences and their neighboring regions. Initially, the sequences of K. pneumoniae Tn4401 (Kp15, Kp512, Kp529-1) were used as a query in BLASTn/NCBI to search for strains of the Proteeae tribe. Then the selected GenBank files were used in Islandviewer 4.0 software for similarity and synteny analysis and the FASTAS sequences were incorporated into ClustalW/MEGA 11. After alignment, the ratio non-synonymous for synonymous substitutions was established. Different isoforms of Tn4401 were revealed, between them Tn4401a, Tn4401b and Tn4401d containing blaKPC. Several patterns of gene sitenia of transposon were detected, involving deletions, inversions, duplications and mobility of neighboring gene groups, sometimes similar, sometimes different. Purifying selection was an active force in the β-lactamases of the analyzed strains. We also detected a possible relationship between the transposon isoforms and neighboring islands of resistance to Mercury, Chromate and Sulfonamide. These findings emphasize the continuous action of different evolutionary processes on plasmids and on the Tn4401 element, as well as the possible potential for dissemination of resistance genes by the Proteeae tribe.
Prospecção da atividade antimicrobiana de polissacarídeos extraídos das paredes celulares das leveduras Kluyveromyces marxianus, Kluyveromyces lactis e Saccharomyces cerevisiae
(2021-02-26) Araújo, Isabelle Maria Feitosa de; Ferreira, Éder Galinari; http://lattes.cnpq.br/7670722046479986; http://lattes.cnpq.br/5044579569126838
Polysaccharides from the most diverse sources, may have pharmacological activities such as, for example, antioxidant, immunomodulatory, anticoagulant and antimicrobial. Bearing in mind that this last activity has not yet been evaluated, according to our bibliographic survey, for the cell wall polysaccharides of the yeasts Kluyveromyces marxianus and Kluyveromyces lactis, the objective of this study was to verify the antimicrobial activity of polysaccharides extracted from the cell walls of the yeasts Kluyveromyces marxianus CCT7735 and Kluyveromyces lactis CBS2359 and compare them to a non-Kluyveromyes yeast like Saccharomyces cerevisiae CAT-1. The susceptibility tests were performed in Petri dishes (90 x 15 mm) using the Kirby-Bauer disc-diffusion method as recommended by the M 100 supplement of the 29th edition of the Clinical & Laboratory Standards Institute. Ten microliters of the polysaccharide solution (10 mg/mL) solubilized in distilled water and sterilized by filtration were deposited on sterile paper discs (6 mm). Polysaccharides were tested against Escherichia coli ATCC 25922 (positive control: 100/10 μg of piperacillin-tazobactam); Staphylococcus aureus ATCC 29213 (positive controls: 30 μg of cefoxitin and 10 units of penicillin); Pseudomonas aeruginosa ATCC 27853 (positive controls: 100/10 μg of piperacillin-tazobactam and 10 μg of gentamicin); Klebsiella pneumoniae ATCC 700603 (positive control: 10 μg gentamicin) and Enterococcus faecalis ATCC 29212 (positive controls: 30 μg tetracycline and 10 units of penicillin). None of the cell wall polysaccharide samples evaluated inhibited the growth of the pathogenic bacteria strains tested. Thus, at least in native molecules, polysaccharides did not show antimicrobial activity. We suggest that further studies be carried out with the samples evaluated, either for other pharmacological applications/activities or with the chemical modification or modification of the concentration of these polysaccharides, followed by a new test for antimicrobial activity, among others.