155 resultados para microdilution


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has increased during the past 10 years. Its detection is frequently difficult, because they do not always show a minimum inhibitory concentration (MIC) value for carbapenems in the resistance range. Both broth microdilution and agar dilution methods are more sensitive than disk diffusion method, Etest and automated systems. Studies on antimicrobial treatment are based on a limited number of patients; therefore, the optimal treatment is not well established. Combination therapy with two active drugs appears to be more effective than monotherapy. Combination of a carbapenem with another active agent — preferentially an aminoglycoside or colistin — could lower mortality provided that the MIC is #4 mg/l and probably #8 mg/l, and is administered in a higher-dose/prolonged-infusion regimen. An aggressive infection control and prevention strategy is recommended, including reinforcement of hand hygiene, using contact precautions and early detection of CPE through use of targeted surveillance.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

AIMS This study was to investigate and to characterize methicillin-resistant coagulase-positive staphylococci (MRCoPS) harboring in dogs and people associated with dogs in Thailand. METHODS AND RESULTS Staphylococci were collected from 100 dogs, 100 dog owners, 200 small animal veterinarians and 100 people without pet association. Species of MRCoPS were identified phenotypically and genotypically. Molecular characteristics were determined by multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE) and SCCmec typing, and antimicrobial susceptibility was assayed by broth microdilution and by microarray analysis for resistance genes. Methicillin-resistant Staphylococcus pseudintermedius (MRSP), methicillin-resistant Staphylococcus schleiferi subsp. coagulans (MRSSc) and methicillin-resistant Staphylococcus aureus (MRSA) were isolated from dogs (45, 17 and 1%, respectively), veterinarians (8, 2 and 1·5%, respectively) and dog owners (3, 2 and 0%, respectively). Seventeen sequence types (STs) were identified among 83 MRSP isolates which specifically carried SCCmec V, II-III, ΨSCCmec57395 and three uncharacterized SCCmec types. MRSP ST 45, 68 and novel STs including 169, 178, 181 and 183 were shared among canine and human isolates. Most of MRSA ST398 and MRSSc carried SCCmec type V. The MRCoPS commonly displayed multiple resistances to tested antimicrobials and carried various resistance genes. CONCLUSION Variety of MRCoPS, especially new MRSP clones, distributed in dogs and people in Thailand. SIGNIFICANCE AND IMPACT OF THE STUDY The existence of MRCoPS circulating between dogs and humans in Thailand provides indirect evidence of interspecies transmission and represents a potential public health hazard.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Antibiotic resistance in Ureaplasma urealyticum/Ureaplasma parvum and Mycoplasma hominis is an issue of increasing importance. However, data regarding the susceptibility and, more importantly, the clonality of these organisms are limited. We analyzed 140 genital samples obtained in Bern, Switzerland, in 2014. Identification and antimicrobial susceptibility tests were performed by using the Mycoplasma IST 2 kit and sequencing of 16S rRNA genes. MICs for ciprofloxacin and azithromycin were obtained in broth microdilution assays. Clonality was analyzed with PCR-based subtyping and multilocus sequence typing (MLST), whereas quinolone resistance and macrolide resistance were studied by sequencing gyrA, gyrB, parC, and parE genes, as well as 23S rRNA genes and genes encoding L4/L22 ribosomal proteins. A total of 103 samples were confirmed as positive for U. urealyticum/U. parvum, whereas 21 were positive for both U. urealyticum/U. parvum and M. hominis. According to the IST 2 kit, the rates of nonsusceptibility were highest for ciprofloxacin (19.4%) and ofloxacin (9.7%), whereas low rates were observed for clarithromycin (4.9%), erythromycin (1.9%), and azithromycin (1%). However, inconsistent results between microdilution and IST 2 kit assays were recorded. Various sequence types (STs) observed previously in China (ST1, ST2, ST4, ST9, ST22, and ST47), as well as eight novel lineages, were detected. Only some quinolone-resistant isolates had amino acid substitutions in ParC (Ser83Leu in U. parvum of serovar 6) and ParE (Val417Thr in U. parvum of serovar 1 and the novel Thr417Val substitution in U. urealyticum). Isolates with mutations in 23S rRNA or substitutions in L4/L22 were not detected. This is the first study analyzing the susceptibility of U. urealyticum/U. parvum isolates in Switzerland and the clonality outside China. Resistance rates were low compared to those in other countries. We hypothesize that some hyperepidemic STs spread worldwide via sexual intercourse. Large combined microbiological and clinical studies should address this important issue.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A alveolite seca (AS) é uma das complicações pós-operatórias mais comuns e sintomáticas na odontologia, porém, até o momento não há um protocolo de tratamento definido. O composto fenólico guaiacol (Gu) é um dos materiais utilizados para revestimento intra-alveolar devido às suas propriedades analgésicas, antioxidantes e antimicrobianas. Contudo, sua desvantagem é a dificuldade de manipulação decorrente da sua baixa estabilidade, alta volatilidade e sensibilidade à oxidação. Para melhorar suas propriedades e aumentar sua aplicabilidade clínica, um complexo de inclusão de Gu com ß-ciclodextrina (ßcd) foi desenvolvido. A formação do complexo supramolecular de Gu:ßcd foi caracterizada mediante a ressonância magnética nuclear (RMN), nos experimentos de 1H e 2D ROESY. A atividade antibacteriana do Gu e Gu:ßcd frente a Escherichia coli, Staphylococcus aureus, Streptococcus mitis, Streptococcus mutans, Streptococcus sanguis e Aggregatibacter actinomycetemcomitans foi analisada pelo método da microdiluição e sua citotoxicidade em osteoblastos de calvária de rato, foi estudado com o ensaio do MTT. O processo de reparo alveolar induzido pelo Gu:ßcd foi avaliado histologicamente após tratamento de alveolite seca em molares inferiores de ratos. A RMN mostrou correlações espaciais entre os hidrogênios internos (H3 e H5) da ßcd e os hidrogênios aromáticos, H(a) e H(b) do Gu, confirmando a formação do complexo. A complexação do Gu na ßcd potencializou seu efeito antibacteriano e reduziu sua citotoxicidade em osteoblastos. O estudo in vivo evidenciou a ocorrência de ossificação no ápice alveolar dos ratos tratados com Gu:ßcd, no 7o dia. No 14o dia, as trabéculas ósseas ocuparam também o terço médio do alvéolo e no 21o dia, todo o alvéolo se encontrava preenchido por osso neoformado. Estes resultados foram similares ao controle negativo e superiores ao controle positivo (Alvogyl®). Os benefícios obtidos pela inclusão do Gu na ßcd foram demonstrados pela melhora das propriedades biológicas do Gu in vitro e o adequado reparo alveolar in vivo.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The antibacterial activities of water, ethanol and hexane extracts of five Australian herbs (Backhousia citriodora, Anetholea anisata, Eucalyptus staigerana, Eu. olida and Prostanthera incisa) against seven food-related bacteria (Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Enteritidis, Sal. Typhimurium and Staphylococcus aureus) were determined by the microtitre broth microdilution assay. The water extracts of all the herbs displayed no or low antimicrobial activity against all of the bacteria tested with the exception of S. aureus. Relatively high levels of activity (minimum inhibitory concentrations of 125-15.6 mu g ml(-1)) against this pathogen were present in water extracts from all herbs except P. incisa. The ethanol and hexane extracts of all herbs displayed some activity against a number of the bacteria tested, with no one particular herb displaying an obviously higher level or range of activity. Staphylococcus aureus proved to be the most sensitive of the bacteria tested against the solvent extracts with all extracts displaying activity ranging from 125 to 7.8 mu g ml(-1), while E. coli and L. monocytogenes, on the other hand, proved the least sensitive with only five of 15 herb/extract combinations displaying any activity against these pathogens. The extracts of the Australian native herbs examined in this study have potential for application in foods to increase shelf-life or promote safety. (c) 2005 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Objectives Effective skin antisepsis and disinfection of medical devices are key factors in preventing many healthcare-acquired infections associated with skin microorganisms, particularly Staphylococcus epidermidis. The aim of this study was to investigate the antimicrobial efficacy of chlorhexidine digluconate (CHG), a widely used antiseptic in clinical practice, alone and in combination with tea tree oil (TTO), eucalyptus oil (EO) and thymol against planktonic and biofilm cultures of S. epidermidis. Methods Antimicrobial susceptibility assays against S. epidermidis in a suspension and in a biofilm mode of growth were performed with broth microdilution and ATP bioluminescence methods, respectively. Synergy of antimicrobial agents was evaluated with the chequerboard method. Results CHG exhibited antimicrobial activity against S. epidermidis in both suspension and biofilm (MIC 2–8 mg/L). Of the essential oils thymol exhibited the greatest antimicrobial efficacy (0.5–4 g/L) against S. epidermidis in suspension and biofilm followed by TTO (2–16 g/L) and EO (4–64 g/L). MICs of CHG and EO were reduced against S. epidermidis biofilm when in combination (MIC of 8 reduced to 0.25–1 mg/L and MIC of 32–64 reduced to 4 g/L for CHG and EO, respectively). Furthermore, the combination of EO with CHG demonstrated synergistic activity against S. epidermidis biofilm with a fractional inhibitory concentration index of <0.5. Conclusions The results from this study suggest that there may be a role for essential oils, in particular EO, for improved skin antisepsis when combined with CHG.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Bacterial resistance to antibiotics and biocides is a prevalent problem, which may be exacerbated by the commonplace and often unnecessary inclusion of biocides into domestic products. Addition of antimicrobials, to domestic disinfectants has raised concern about promoting microbial resistance and potential cross-resistance to therapeutic antibiotics. This study investigated the potential for resistance in Salmonella enterica serovars Enteritidis, Typhimurium, Virchow and Escherichia call 0157 to commonly used biocides, to identify mechanisms underlying resistance and whether these provided cross-resistance to antibiotics. Salmonella enterica and E. coli 0157 strains were serially exposed to sub-inhibitory. concentrations of erythromycin (ERY), benzalkonium chloride (BKC), chlorhexidine hydrochloride (CHX)and triclosan (TLN). Once resistance was achieved permeability changes in the outer membrane, including LPS, cell surface charge and hydrophobicityand the presence of,an active efflux were investigated as possible resistance candidates. Thin layer chromatography (TLC) and Gas chromatography (GC) were carried out to examine fatty acid and lipid changes in E. coli 0157 isolates with reduced susceptibility to TLN. Cross-resistance was studied by the Stoke's method and standard microdilution assays. Examination of the outer membrane proteins and LPS did not reveal any significant changes between parent and resistant strains. The hydrophobicity of the cells increased as the cells were passaged and became less. susceptible. An active efflux system was the most likely mechanism of resistance in all strains tested and a fab1 mutation was associated with E. coli 0157 resistant to TLN isolates. In all isolates investigated the resistance was stable for over 30 passages in biocide-free media. A high degree of cross-resistance was obtained in TLN-resjstant Escherichia coli 0157 strains, which repeatedly exerted decreased susceptibility to various antimicrobials, including chloramphenicol, erythromycin, imipenem, tetracycline and trimethoprirn:, as well as to various biocides. The results of this laboratory-based investigation suggest that it is possible for microorganisms to become resistant to biocides when repeatedly exposed to sublethal concentrations. This may be especially the case in the domestic environment where administration of biocides is poorly controlled. Eventually it could lead to the undesirable situation of resident strains becoming resistant to disinfection and cross resistant to other antimicrobials.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In many vertebrate and invertebrate species mediators of innate immunity include antimicrobial peptides (AMPs) such as peptide fragments of histones and other proteins with previously ascribed different functions. Shark AMPs have not been described and this research examines the antibacterial activity of nurse shark (Ginglymostoma cirratum) peripheral blood leukocyte lysates. Screening of lysates prepared by homogenizing unstimulated peripheral blood leukocytes identified muramidase (lysozyme-like) and non-muramidase antibacterial activity. Lysates were tested for lysozyme using the lysoplate assays, and antibacterial (AB) activity was assayed for by a microdilution growth assay that was developed using Planococcus citreus as the target bacterium. Fractionation of crude lysates by ion exchange and affinity chromatography was followed by a combination of SDS-PAGE with LC/MS-MS and/or N-terminal sequence analysis of low molecular weight protein bands (<20 kDa). This yielded several peptides with amino acid sequence similarity to lysozyme, ubiquitin, hemoglobin, human histones H2A, H2B and H4 and to antibacterial histone fragments of the catfish and the Asian toad. Not all peptide sequences corresponded to peptides potentially antibacterial. The correlation of a specific protein band in active lysate fractions was accomplished by employing the acid-urea gel overlay assays in which AB activity was seen as zones of growth inhibition on a lawn of P. citreus at a position corresponding to that of the putative AB protein band. This study is the first to describe putative AMPs in the shark and their potential role in innate immunity.^

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Helicobacter pylori is a spiral, Gram negative, mobile, and microaerophilic bacteria recognized as a major cause of gastritis, ulcer, gastric cancer, and gastric low grade, B cell, mucosa – associated lymphoid tissue (MALT) lymphoma, constituting an important microorganism in medical microbiology. Its importance comes from the difficulty of treatment because the requirement of multiple drugs use, besides the increasing emergence of resistant and multiresistant strains to antibiotics used in th e clinic. In order to expand safe and effective therapeutic options , chemical studies on medicinal plants by obtaining extracts, fractions, isolated compounds or essential oils with some biological activity has been intensified . Given the above, the objective was to evaluate the inhi bitory activity of organic extracts derived from Syzygium cumini and Encholirium spectabile, with antiulcer history, and the essential oil, obtained from S. cumini, against H. pylori (ATCC 43504) by the disk diffusion method, for qualitative evaluation, an d determination of minimum inhibitory concentration (MIC) using the broth microdilution method, for quantitative analysis. Also was evaluated the extracts in vitro toxicity by a hemolytic assay using sheep red blood cells, and VERO and HeLa cells using the MTT assay to analyze cell viability. The extracts of both plant used in antimicrobial assays did not inhibit bacterial growth, however the essential oil of S. cumini (SCFO) proved effective, showing MIC value of 205 μg/mL (0.024 % dilution of the original oil). In the hemolytic assay, the same oil shows moderate toxicity, by promote 25% hemolysis at 1000 μg/mL. Regarding the cytotoxicity in cell culture, the SCFO, at 260 μg/mL, affected the cell viability around 80% of HeLa and 50% of VERO cells. So the oi l obtained from S. cumini leaves has antimicrobial activity against H. pylori and cytotoxicity potential, suggesting a source of new molecule drug candidates, since new stages of toxicity in vitro and in vivo, as well, chemical characterization be evaluate d. Moreover, the development of a prospective drug delivery system can result in a prototype to be used in preclinical tests.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Introduction: The production of KPC (Klebsiella pneumoniae carbapenemase) has become an important mechanism of carbapenem-resistance among Enterobacteriaceae strains. In Brazil, KPC is already widespread and its incidence has increased significantly, reducing treatment options. The “perfect storm” combination of the absence of new drug developmentand the emergence of multidrug-resistant strains resulted in the need for the use of older drugs, with greater toxicity, such as polymyxins. Aims: To determine the occurrence of carbapenemase-producing strains in carbapenem-resistant Enterobacteriaceae isolated from patients with nosocomial infection/colonization during September/2014 to August/2015, to determine the risk factors associated with 30-day- mortality and the impact of inappropriate therapy. Materials and Methods: We performed a case control study to assess the risk factors (comorbidities, invasive procedures and inappropriate antimicrobial therapy) associated with 30-day-mortality, considering the first episode of infection in 111 patients. The resistance genes blaKPC, blaIMP, blaVIM and blaNDM-1 were detected by polymerase chain reaction technique. Molecular typing of the strains involved in the outbreak was performed by pulsed field gel electrophoresis technique. The polymyxin resistance was confirmed by the microdilution broth method. Results: 188 episodes of carbapenem-resistant Enterobacteriaceae infections/colonizations were detected; of these, 122 strains were recovered from the hospital laboratory. The presence of blaKPC gene were confirmed in the majority (74.59%) of these isolates. It was not found the presence of blaIMP , blaVIM and blaNDM-1 genes. K. pneumoniae was the most frequent microorganism (77,13%), primarily responsible for urinary tract infections (21,38%) and infections from patients of the Intensive Care Unit (ICU) (61,38%). Multivariate statistical analysis showed as predictors independently associated with mortality: dialysis and bloodstream infection. The Kaplan-Meier curve showed a lower probability of survival in the group of patients receiving antibiotic therapy inappropriately. Antimicrobial use in adult ICU varied during the study period, but positive correlation between increased incidence of strains and the consumption was not observed. In May and July 2015, the occurrence rates of carbapenem-resistant Enterobacteriaceae KPC-producing per 1000 patient-days were higher than the control limit established, confirming two outbreaks, the first caused by colistin-susceptible KPC-producing K. pneumoniae isolates, with a polyclonal profile and the second by a dominant clone of colistin-resistant (≥ 32 μg/mL) KPC-producing K. pneumoniae. The cross transmission between patients became clear by the temporal and spatial relationships observed in the second outbreak, since some patients occupied the same bed, showing problems in hand hygiene adherence among healthcare workers and inadequate terminal disinfection of environment. The outbreak was contained when the ICU was closed to new admissions. Conclusions: The study showed an endemicity of K. pneumoniae KPC-producing in adult ICU, progressing to an epidemic monoclonal expansion, resulted by a very high antibiotic consumption of carbapenems and polymyxins and facilitated by failures in control measures the unit.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Banisteriopsis genus is widespread in traditional medicine. This work aims to contribute with information about the chemical composition and on the evaluation of the biological activity of the essential oil, the ethanol extract of the leaves and partitions of the Banisteriopsis laevifolia. The phytochemical screeningtest of ethanol extract and partitions of leaves indicated the presence of flavonoids, terpenoids, saponins, phenols and steroids compounds. Nitrogenous compounds, characteristic of some species of this family, were not detected. Flavonoids were the predominant metabolite, with the highest concentrations on the partitions ethyl acetate and n-butanol. The antibacterial activity, antifungal and cytotoxicity of the essetial oil, ethanol extract and partitions were assyed by microdilution broth method (MBM), where the minimum inhibitory concentrations (MIC) were calculated. The ethanol extract and partitions did not inhibit growth against to Gram positive bacteria tested, with MIC less than 400 mg L-1. For the Gram negative bacteria tested, the hexane and hydroethanol partitios were more effective against F. nucleatum bacteria (MIC 100 ug mL-1). The ethanol extract showed antifungal activity with MIC of 31.2 mg L-1. Ethyl acetate and n-butanol partitions showed MIC 187.5 mg L-1 and 93.7 mg L-1, respectively, arousing interest for isolation studies. The antioxidant activity was evaluated by the DPPH free radical method. The ethanolic extract, ethyl acetate and n-butanol partitions were active, since they showed EC50 values (4.53 ug mL-1, 4.07 and 8.39 ug mL-1, respectively), values equivalent to the BHT (7.3 mg L-1). The analysis by HPLC-MS/MS of the most active fractions (ethyl acetate and n-butanol) identified phenolic compounds (flavonols and phenolic acids) which exert recognized biological activity. The GC-MS analysis of the essential oils from leaves collected in two periods studied (dry and wet), showed a small variation in the number of compounds. The major classes identified for the oil collected in the dry period were aliphatic alcohols (23,4%), terpenoids (18.7%), sterols (10.4%) and long-chain alkanes (9.2%) compounds. Terpenoids (26.8%) were the major class for the rain season. The major compounds (3Z) -hexenol, phytol and untriacontano are present in the two seasons but in different amounts (19.4%, 9.8% and 7.5% during the dry season, and 17.0 %, 14.9% and 15.3% in the rainy season, respectively). The essential oil from rainy season was not effective against to the oral bacteria Gram positive and Gram negative tested. However, showed significant antifungal activity with MIC 1000 mg L-1 against Candidas. Thus, the promising results with respect to biological assays of ethanolic extract and partitions from B. laevifolia contributed to the chemical and biological knowledge of the species B. laevifolia.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pseudomonas aeruginosa is a major cause of morbidity and mortality in cystic fibrosis patients. This study compares the antimicrobial susceptibility of 153 P. aeruginosa isolates from the United Kingdom (UK) (n=58), Belgium (n=44), and Germany (n=51) collected from 120 patients during routine visits over the 2006-2012 period. MICs were measured by broth microdilution. Genes encoding extended spectrum β-lactamases (ESBL), metallo-β-lactamases and carbapenemases were detected by PCR. Pulsed Field Gel Electrophoresis and Multi-Locus Sequence Typing were performed on isolates resistant to ≥ 3 antibiotic classes among penicillins/cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, polymyxins. Based on EUCAST/CLSI breakpoints, susceptibility was ≤ 30%/≤ 40% (penicillins, ceftazidime, amikacin, ciprofloxacin), 44-48%/48-63% (carbapenems), 72%/72% (tobramycin), and 92%/78% (colistin) independently of patient's age. Sixty percent of strains were multidrug resistant (MDR; European Centre for Disease prevention and Control criteria). Genes encoding ESBL (most prevalent BEL, PER, GES, VEB, CTX-M, TEM, SHV, and OXA), metallo β-lactamases (VIM, IMP, NDM), or carbapenemases (OXA-48, KPC) were not detected. The Liverpool Epidemic Strain (LES) was prevalent in UK isolates only (75% of MDR isolates). Four MDR ST958 isolates were found spread over the three countries. The other MDR clones were evidenced in ≤ 3 isolates and localized in a single country. A new sequence type (ST2254) was discovered in one MDR isolate in Germany. Clonal and non-clonal isolates with different susceptibility profiles were found in 21 patients. Thus, resistance and MDR are highly prevalent in routine isolates from 3 countries, with carbapenem (meropenem), tobramycin and colistin remaining the most active drugs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Baccharis oreophila Malme belongs to the Asteraceae family. In Brazil are reported 120 species of Baccharis, most located in the South and Southeast regions, the latter presents the highest prevalence, especially in the state of São Paulo. Asteraceae is well known for the production of essential oils, which are liquid, volatile and aromatic substances produced by plants specialized for metabolism possess antibacterial, antifungal, and antioxidant properties. Thus, this study aimed, perform chemical and evaluate the antimicrobial and antioxidant activity of essential oil from dried leaves of B. oreophila collected in winter in Piraquara, Paraná. Obtaining essential oil was given by hydrodistillation in Clevenger apparatus, in triplicate, and the analysis was done using a gas chromatograph coupled to mass spectrometry GC / MS. The identification of the components was made based on retention indices calculated from the co-injection of a series of n-alkanes, followed by comparison of their mass spectra with literature. The antimicrobial activity was assessed by disk diffusion method and microdilution. The antioxidant activity was evaluated by the methods DPPH equivalent Trolox, ABTS and FRAP equivalent Trolox equivalent ferrous sulfate. The essential oil showed 0.47% yield. They identified 57 components (89.38%), 1.51% were classified as hydrogenated monoterpenes, oxygenated monoterpenes 15.14%, 34.84% and 37.87% hydrogenated sesquiterpenes sesquiterpenes oxygenates. As the major components were detected kusimono (16.37%), spathulenol (16.12%), the δ-cadinene (5.68%) and bicyclogermacrene (4.09%). The antimicrobial activity of essential oil was performed for the microorganisms Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Candida albicans ATCC 18804 and Candida tropicalis ATCC 13803, the results showed that the essential oil showed activity against S. aureus Inhibitory Concentration minimum (CIM) 1250 g/mL. In the evaluation of antioxidant activity essential oil showed antioxidant potential for the three methods evaluated, with values of 1,468 m.mol.L-1, 7.126 m.mol.L-1 and 45.515 m.mol.L-1 for ABTS, DPPH and FRAP, respectively. These results demonstrate that the essential oil of B. oreophila showed antimicrobial potential against S. aureus and interesting antioxidant activity, especially for the reducing power of iron ion, demonstrating their potential for future industrial applications. It is important to emphasize that were not observed in the literature reports highlighting such biological properties of B. oreophila oil.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: The emergence of multiple-drug resistance bacteria has become a major threat and thus calls for an urgent need to search for new effective and safe anti-bacterial agents. Objectives: This study aims to evaluate the anticancer and antibacterial activities of secondary metabolites from Penicillium sp. , an endophytic fungus associated with leaves of Garcinia nobilis . Methods: The culture filtrate from the fermentation of Penicillium sp. was extracted and analyzed by liquid chromatography– mass spectrometry, and the major metabolites were isolated and identified by spectroscopic analyses and by comparison with published data. The antibacterial activity of the compounds was assessed by broth microdilution method while the anticancer activity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results: The fractionation of the crude extract afforded penialidin A-C (1-3), citromycetin (4), p-hydroxyphenylglyoxalaldoxime (5) and brefelfin A (6). All of the compounds tested here showed antibacterial activity (MIC = 0.50 – 128 μg/mL) against Gramnegative multi-drug resistance bacteria, Vibrio cholerae (causative agent of dreadful disease cholera) and Shigella flexneri (causative agent of shigellosis), as well as the significant anticancer activity (LC50 = 0.88 – 9.21 μg/mL) against HeLa cells. Conclusion: The results obtained indicate that compounds 1-6 showed good antibacterial and anticancer activities with no toxicity to human red blood cells and normal Vero cells.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Helicobacter pylori is a bacterium recognized as the major cause of chronic gastritis and peptic ulcers. Infection by H. pylori induces inflammatory responses and pathological changes in the gastric microenvironment. The host Keywords: immune cells (especially neutrophils) release inflammatory mediators and large 5-methoxy-3,4-dehydroxanthomegnin amounts of reactive oxygen species (ROS), which are associated with an increased Helicobacter pyloririsk of developing gastric cancer. In this study, we evaluated the anti-H. pylori and oxidative burst antioxidantactivitiesofa1,4-naphthoquinone-5-methoxy-3,4-dehydroxanthomegnin. Paepalanthus latipes The antimicrobial activity was assessed using a spectrophotometric microdilution technique, and antioxidant activity was assessed by noting the effect of 5-methoxy3,4-dehydroxanthomegnin on the neutrophil oxidative burst using luminol-and lucigenin-amplified chemiluminescence. The results showed that 5-methoxy-3,4dehydroxanthomegnin is a potent anti-H. pylori compound (MIC 64 µg/mL and MBC 128 µg/mL) and a strong antioxidant. 5-Methoxy-3,4-dehydroxanthomegnin decreased luminol- and lucigenin-amplified chemiluminescence, with ED50 values of 1.58±0.09 µg/mL and 5.4±0.15 µg/mL, respectively, reflecting an inhibitory effect on the oxidative burst. These results indicate that 5-methoxy-3,4-dehydroxanthomegnin is a promising compound for the prevention and treatment of diseases caused by H. pylori infection, such as gastritis, peptic ulceration, and gastric cancer, because reactive oxygen intermediates are involved in the pathogenesis of gastric mucosal injury induced by H. pylori infections.