Inhibition Of Bacterial Activity Research Articles

Atividade antibacteriana in vitro de pimentas e pimentões (Capsicum sp.) sobre quatro bactérias toxinfectivas alimentares

Determinou-se in vitro a Intensidade de Atividade de Inibição Bacteriana (IINIB) e a Intensidade de Atividade de Inativação Bacteriana (IINAB), através de Testes de Diluição em Sistema de Tubos Múltiplos, de extratos de oito pimentas do gênero Capsicum, etnograficamente acessadas na região metropolitana de Porto Alegre/RS/BR, frente a inóculos bacterianos padronizados (American Type Culture Collection - ATCC), respectivamente Staphylococcus aureus (25923), Enterococcus faecalis (19433), Salmonella enteritidis (13076) e Escherichia coli (11229), em doses-desafio = 10(7) UFC mL-1. Quatro destas plantas, pimenta calabresa ("pool" Capsicum sp), pimenta-de-jardim (C.annuum), pimenta dedo-de-moça (C. baccatum) e pimenta malagueta (C. frutescens), apresentaram atividades de inibição e inativação seletivas, em ordem decrescente, para salmonela, coliforme fecal, enterococo e estafilococo. As demais, pimenta cambuci (C. baccatum) e os pimentões (C. annuum) amarelo, verde e vermelho, apresentaram nenhuma atividade. Discute-se a validade da ferramenta etnográfica na prospecção de fatores de proteção anti-bacteriana em plantas, bem como a influência da inibição/inativação na preditividade do diagnóstico bacteriológico.

Inibição e inativação de Escherichia coli por extratos de plantas com indicativo etnográfico medicinal ou condimentar

The in vitro Intensity of Bacterial Inhibition Activity (IINIB) and the Intensity of Bacterial Inactivation Activity (IINAB) of diverse aqueous alcoholic/hydroalcoholic from extracts of 59 plants with medicinal or spice ethnographic indicative assessed in Porto Alegre/RS/BR, were determinated against Escherichia sp. (or E. coli ATCC no 11229 or E. coli p.16 CPVDF - SAA/RS) in challenge doses < 108 CFU.mL-1. Extracts of 30 plants presented some anti-Escherichia coli selective activity while the remaining 29 plants presented no activity. The validity of ethnographical search instruments in the prospection of anti-bacterial protection factors in plants and the influence of inhibition/inactivation results in the prediction of E. coli diagnostic were discussed.

Inibição e inativação in vitro de Salmonella spp. com extratos de plantas com indicativo etnográfico medicinal ou condimentar

Determinou-se in vitro a intensidade de atividade de inibição bacteriana e a intensidade de atividade de inativação bacteriana, por meio de testes de diluição e suspensão em sistema de tubos múltiplos, de diferentes extratos, aquosos ou alcoólicos/hidroalcoólicos, de 86 plantas com indicativo etnográfico medicinal ou condimentar acessadas na região metropolitana de Porto Alegre, Rio Grande do Sul, frente a Salmonella spp., ou S. enteritidis ATCC nº 13076, ou S. cholera-suis ATCC nº10708, ou S. gallinarum CPVDF-SAA/RS/BR, em doses-desafio de &lt;10(7)UFC.mL-1. Cinquenta plantas apresentaram alguma atividade seletiva antissalmonela, e 37 nenhuma atividade. Discute-se a validade da ferramenta etnográfica na prospecção de fatores de proteção antibacteriana em plantas, bem como a influência da inibição/inativação na preditividade do diagnóstico bacteriológico.

Atividade antibacteriana in vitro de extratos de alho nirá (Allium tuberosum Rottler ex Spreng.)

Com o objetivo de demonstrar a influência da condimentação sobre a Validade Preditiva dos Resultados Negativos do diagnóstico de bactérias transmissíveis por alimentos, determinou-se, in vitro, a intensidade de atividade de inibição bacteriana (IINIB) e a intensidade de atividade de inativação bacteriana (IINAB) de três acessos de Allium tuberosum Rottler ex Spreng. - Liliaceae - alho "nirá", originários da região metropolitana de Porto Alegre, Rio Grande do Sul. O extrato etanólico à 50% destes diferentes acessos (alcoolaturas com evaporação do etanol em sistema rotavapor com reconstituição hídrica sob assepsia) foi testado, através de testes de diluição em sistema de tubos múltiplos, sobre inóculos padronizados de Staphylococcus aureus (ATCC 25.923), Enterococcus faecalis (ATCC 19.433), Salmonella enteritidis (ATCC 11.076), Escherichia coli (ATCC 11.229). Os testes revelaram atividade antibacteriana seletiva sobre os diferentes inóculos Gram-negativos, que atingiram inibição e inativação máximas e permanentes para Salmonella após 48 horas, e, para Escherichia coli, após 72 horas de exposição. As bactérias Gram-positivas, Staphylococcus e Enterococcus, apresentaram resistência total frente aos extratos etanólicos Não houve diferença significativa entre si quanto aos tempos de atuação, quanto a Salmonella e Escherichia, quanto à presença ou ausência de desinibidores bacterianos, havendo, entretanto, diferença significativa entre os acessos de alho nirá.

Atividade antibacteriana de extratos de erva mate (Ilex paraguariensis A.St.-Hil.)

Através de testes de diluição, em sistema de tubos múltiplos, determinou-se a intensidade de atividade de inibição bacteriana (IINIB) e intensidade de atividade de inativação bacteriana (IINAB) de extratos hídricos (decocto), etanólicos (alcoolatura e hidroalcoolatura) de cambitos e de folhas de Ilex paraguariensis A.St.-Hil.(Aquifoliaceae) sobre as bactérias Staphylococcus aureus (ATCC 25.923), Enterococcus faecalis (ATCC 19.433), Salmonella enteritidis (ATCC 11.076) e Escherichia coli (ATCC 11.229). Todas as formas de extração apresentaram capacidade de inativação e/ou inibição seletivas sobre as bactérias avaliadas, porém os extratos originados por destilação etanólica apresentaram os melhores resultados. Salmonella enteritidis demonstrou maior sensibilidade, seguida por Enterococcus faecalis. Posteriormente, estes dois agentes foram submetidos a testes de suspensão, no mesmo sistema, na presença e ausência de matéria orgânica (soro bovino), sob controle do fator tempo. A presença de matéria orgânica diminuiu, enquanto o tempo de exposição aumentou a sensibilidade de Salmonella enteritidis e de Enterococus faecalis aos diferentes extratos de Ilex testados.

Synthesis and antibacterial activity of 5-methoxy- and 5-hydroxy-6-fluoro-1,8-naphthyridone-3-carboxylic acid derivatives

A series of 5-methoxy- and 5-hydroxy-6-fluoro-1,8-naphthyridone-3-carboxylic acid derivatives were prepared and evaluated for cell-free bacterial protein synthesis inhibition and whole cell antibacterial activity. When compared to the analogous 5-hydrogen compounds, the presence of the 5-OH group negatively affects biochemical potency. However, a tolerance of the 5-methoxy group is indicated. Only moderate whole cell antibacterial activity is seen, but this could be due to poor cellular penetration. Because only a few 7-position variants were made for this study, further investigation into this novel series combining a broader range of 7-amino derivatives with these 5-position modifications is warranted.

Diminished efficiency in the oceanic silica pump caused by bacteria‐mediated silica dissolution

Previous laboratory findings indicated that marine bacteria accelerate biogenic silica (bSiO2) dissolution rates in the sea by degrading the organic coating surrounding diatom frustules and exposing the underlying silica to chemical attack by undersaturated seawater. We examined the effectiveness of bacterial activity in facilitating in situ bSiO2 dissolution during a diatom bloom in Monterey Bay, California, following moderate upwelling. Inhibition of bacterial activity with antibiotics and protease inhibitors reduced specific bSiO2 dissolution rates (Vdis) at five of six stations, with a reduction of 44 ± 27% (mean ± SD, n = 6, range 22–91%) over 24 h. Reduced Vdis in inhibitor treatments corresponded with reductions in abundance, production, and proteolytic activity of attached bacteria. Dissolution rates were highly correlated with protease activity integrated from the surface down to the depth where each dissolution was measured, suggesting that increased Vdis with depth in the upper 20–80 m of the ocean is caused by the progressive removal of organic matter from frustules during sinking. Facilitation of bSiO2 dissolution by in situ bacterial assemblages varied between stations and was likely influenced by the physiological condition of resident diatom assemblages. Denaturing gradient gel electrophoresis and 16S rRNA gene sequencing of bacteria colonizing in situ diatom assemblages confirmed previous findings that specific bacterial phylotypes (Cytophaga/Flavobacteria/Bacteriodes; a and g subclasses of Proteobacteria) mediate bSiO2 dissolution.

Antibacterial Activity of the White Precipitate Formed on the Corneal Surface After Treatment with Ciprofloxacin Ophthalmic Solution

To determine the antibacterial activity of the white crystalline precipitate formed on the corneal surface after topical administration of 0.3% ciprofloxacin ophthalmic solution by microbiologic assay. White crystalline precipitate formed on the corneal surface of seven patients was scraped and individually dissolved in sterile distilled water. Quantification by high-performance liquid chromatography (HPLC) and microbiologic assay of ciprofloxacin in the precipitate solutions were done. Microbiologic assay was performed by agar diffusion method against Klebsiella pneumoniae. By HPLC, concentrations of ciprofloxacin were estimated to be 1.5-60 microg/ml in the dissolved precipitate obtained from six patients, whereas the concentrations based on microbiologic assay varied from 1.6 to 16.1 microg/ml. Ciprofloxacin was not detected by either method in the precipitate obtained from one patient. The antibacterial activity (microg/ml) determined by microbiologic assay was not related to the actual amount of ciprofloxacin in the solutions as estimated by HPLC in cases 1, 2, 4, and 7. It was almost the same in the solutions from cases 5 and 6. The white crystalline precipitate formed on the corneal surface after topical administration of 0.3% ciprofloxacin ophthalmic solution exhibited bacterial inhibitory activity, indicating that the precipitate may function as a drug depot.

Contact Lens-Induced Peripheral Ulcers with Extended Wear of Disposable Hydrogel Lenses

Contact lens-induced peripheral ulcer (CLPU), a sudden-onset adverse event observed with extended wear of hydrogel lenses, is characterized by a single, small, circular, focal anterior stromal infiltrate in the corneal periphery or midperiphery. The condition is always associated with a significant overlying epithelial loss and resolves in a scar. The aim was to determine, by using histopathologic techniques, the nature and type of the corneal infiltrate of these events. Three CLPUs observed in three patients using disposable hydrogel lenses on an extended-wear schedule were examined. The eye was topically anesthetized, and a corneal section including all of the infiltrate was taken. A small triangular piece of conjunctiva immediately adjacent to the infiltrate was sectioned. The tissue was immediately fixed, processed, stained using hematoxylin and eosin and periodic acid-Schiff stains, and examined by using light microscopy. The diameter of these three corneal infiltrates varied from 0.3 to 0.6 mm. Histopathology of the corneal sections revealed a focal epithelial loss corresponding to the infiltrated stroma in all three patients. The adjacent epithelium was thinned. Bowman's layer was intact in two patients and had a localized area of loss in the remaining patient. The anterior stroma was densely infiltrated with polymorphonuclear leukocytes and had focal areas of necrosis. The infiltration was most dense in the region immediately underlying Bowman's layer. No other infiltrative cell type was seen in any of the sections. Histopathology of the conjunctiva revealed features consistent with normal conjunctival tissue. On histopathology of CLPU, distinctive features (i.e., focal corneal epithelial loss, an intact Bowman's membrane, and a localized infiltration of the anterior stroma with polymorphonuclear leukocytes) were seen. These features suggest that the event is an acute inflammatory process and probably noninfective in nature.

Organic matter decay in coastal wetlands: an inhibitory role for essential oil from Melaleuca alternifolia leaves?

Essential oils are a common component of the leaves of many plants, and may be a factor that, to date, has been overlooked as a determinant of leaf decay in natural environments. Cellulose sheets and dried leaves of Platanus sp. (common plane tree) treated with essential oil extracted from Melaleuca alternifolia CHEEL and buried in soil in laboratory mesocosms decayed at a significantly slower rate than did control materials not treated with the oil. Inhibition of bacterial activity may account in part for this effect on organic matter decay, since Melaleuca essential oil at concentrations of greater than 0.001% v/v markedly inhibited the growth of the bacterium, Escherichia coli. Melaleuca essential oil was lethal to starved bacteria (E. coli, Staphylococcus aureus and Pseudomonas aeruginosa), especially at higher concentrations (>0.I % v/v) of the oil. EC 50 values, determined with the Microtox assay, were c. 0.01 % v/v, a value equivalent to an essential oil concentration of about 100mg/l. Essential oil derived from Melaleuca leaves and twigs may have a significant role in organic matter processing and nutrient cycling in coastal wetlands by slowing the decomposition of organic detritus and inhibiting or killing microbes.

Antibacterial Activity of Heated Cabbage Juice, S‐Methyl‐L‐Cysteine Sulfoxide and Methyl Methanethiosulfonate

ABSTRACTAutoclaved cabbage juice was inhibitory to growth of Staphylococcus aureus. S‐Methyl‐L‐cysteine sulfoxide (SMCSO), autoclaved either together with or separately from nutrient broth, also inhibited the growth of S. aureus, but inhibition was greater when SMCSO was autoclaved separately. Methyl methanethiosulfonate (MMTSO2), a thermal breakdown product of SMCSO, completely inhibited growth of S. aureus at 10 ppm. MMTSO2 was formed in both autoclaved samples of cabbage juice and aqueous solution of SMCSO. Thus, evidence indicates that the bacterial inhibitory activity in autoclaved cabbage juice was due to heatinduced formation of MMTSO2 from SMCSO.

Inhibition Effects of Zinc and Copper on Volatile Fatty Acid Production During Anaerobic Digestion

The inhibition of copper and zinc ions on the acidogenesis phase in anaerobic treatment was studied. Glucose acclimated anaerobic bacterial sludge was used in the inhbition experiments. Metals were introduced as shock doses to batch reactors. Inhibition of bacterial activity was quantified by individual volatile fatty acid measurements. For both metals, production activity of propionic acid was the most severely affected, with acetic acid being the next. Copper was more toxic to the bacterial culture. Mixtures of the two metal ions exhibited a clear antagonistic behaviour on inhibition of volatile acid production.

Inhibition of bovine dihydrofolate reductase and enhancement of methotrexate sensitivity by N4-(2-acetoxyethoxymethyl)-2acetylpyridine thiosemicarbazone

N 4-(2-Acetoxyethoxymethyl)-2-acetylpyridine thiosemicarbazone (AATSC) belongs to a series of molecules known to have broad antimicrobial inhibitory activity. These molecules contain the 2-acetoxyethoxy moiety which could conceivably take up a conformation analogous to that of the ribosyl group. Moreover, the thiosemicarbazone moiety, when it the presence of a suitable enzymatic site, could mimic the triazine group, which is found in a number of antifolate drugs. AATSC, which has both bacterial inhibitory activity and water solubility, was accordingly evaluated for its antifolate activity against the bovine liver dihydrofolate reductase. AATSC is shown to be a fully uncompetitive inhibitor of that enzyme. Furthermore, AATSC enhances the activity of methotrexate. Such a potentiation could be useful for therapeutic purposes.

Inhibition of bacterial activity in acid mine drainage

Acid mine drainage water give rise to rapid growth and activity of an iron- and sulphur- oxidizing bacteriumThiobacillus ferrooxidians which greatly accelerate acid producing reactions by oxidation of pyrite material associated with coal and adjoining strata. The role of this bacterium in production of acid mine drainage is described.

The association between the absence of amniotic fluid bacterial inhibitory activity and intra-amniotic infection

We studied the relationship of amniotic fluid bacterial inhibition in 50 patients with intra-amniotic infection to that in 50 matched control patients. Amniotic fluid was collected through a transcervical intrauterine catheter. All infected patients had clinical signs of intra-amniotic infection and ≥102 colony-forming units per milliliter of a high-virulence organism. None of the control patients became infected. The matching characteristics for the intra-amniotic infection group versus the control group were: interval from rupture of the membranes to delivery (14.30 ± 7.96 versus 15.00 ± 7.19 hours, NS), interval from rupture of the membranes to collection of amniotic fluid (12.41 ± 6.37 versus 12.16 ± 6.46 hours, NS), and gestational age (40.3 ± 1.6 versus 40.0 ± 1.6 weeks, NS). All patients were in labor. We tested each sample of amniotic fluid for inhibitory activity to Escherichia coli by a plate-count technique. Thirty-five samples (70%) of intra-amniotic infection fluid were noninhibitory, whereas 16 samples (32%) of control fluid were noninhibitory. The conclusion was that amniotic fluid from patients with intra-amniotic infection was significantly less likely to be inhibitory to E. coli (p < 0.001).

Inorganic phosphorus and zinc concentrations in amniotic fluid: Correlation with intra-amniotic infection and bacterial inhibitory activity

Concentrations of zinc and inorganic phosphorus were determined in amniotic fluid from 41 patients with intra-amniotic infection and from 40 uninfected, control patients. Also determined was amniotic fluid inhibitory activity to an Escherichia coli test organism. Compared to amniotic fluid from control patients, that from patients with intra-amniotic infection had significantly higher mean concentrations of phosphorus. In specimens free of meconium, the mean concentrations of phosphorus were still significantly higher. Assays for inhibitory activity were performed with 62 samples of fluid (25 noninhibitory, 37 inhibitory). Although noninhibitory fluid had higher mean concentrations of phosphorus and zinc, these differences did not hold after meconium-stained samples were excluded. No correlation was found between phosphorus-to-zinc ratio and either intra-amniotic infection or inhibitory activity. However, there are important differences in population and techniques between this and related studies.

Role de l'ozone sur l'adsorbabilité et la biodégradabilité de quelques composes organiques sur charbon actif en grains effect of ozone on adsorbability and biodegradibility of a few organic compounds over granular activated carbon

Abstract The Freundlich isotherms of phenol and of its ozonation products, in synthetic solution, show that these products are less adsorbed than the phenol itself. The same results are obtained with solutions of phenol ozonated at different rates, in filtered surface water. However, the GAC filtration of ozonated phenol dissolved in surface water produces a very important uptake of TOC. ATP measurements at different levels of the GAC column express bacterial activity, in relation with the percentage of TOC removal. Moreover, inhibition of bacterial activity due to the introduction of a silver salt leads to a drop of TOC elimination.

Bacterial growth inhibition by amniotic fluid: VII. The effect of zinc supplementation on bacterial inhibitory activity of amniotic fluids from gestation of 20 weeks

Twenty human amniotic fluids obtained from gestations of 20 weeks' duration supported bacterial growth. Nine of the 20 fluids could be made inhibitory by adjusting the phosphate to zinc ratios of the fluids to less than 200 μg per milliliter. These fluids contained the phosphate-sensitive bacterial inhibitor described previously, but the fluids contained sufficient phosphate to inactivate the antibacterial system. The remaining 11 amniotic fluids did not contain the peptide component of the phosphate-sensitive bacterial inhibitor and could not be made inhibitory by adjusting the phosphate to zinc ratio to less than 200 μg per milliliter. The data obtained suggested synthesis of the peptide component may occur at a gestational age of approximately 20 weeks. The peptide may indirectly be detected in fluids by determining whether antibacterial activity is obtained when the phosphate to zinc ratio of the fluids is adjusted to less than 200 μg per milliliter.

Isolation of a low-molecular-weight antibacterial system from human amniotic fluid.

A low-molecular-weight antibacterial system has been isolated from human amniotic fluid. The bacterial inhibitor requires the metal cation zinc and a peptide with a molecular weight of 630. The peptide component was purified using ultrafiltration, gel filtration, and ion-exchange chromatography. It can be inactivated by digestion with carboxypeptidase. The amino acid composition of the peptide is: 3 glutamine-glutamic acid, 2 glycine, and 1 lysine. Removal of zinc from the peptide has been shown to remove bacterial inhibitory activity.

Bacterial interference by oropharynegeal and clinical isolates of anaerobic bacteria.

Anaerobic isolates were tested for bacterial inhibitory activity. Of 144 isolates, 102 were from oropharynegeal washings, and 42 were from clinical specimens. Thirteen facultative bacterial species (seven members of the Enterobacteriaceae and six species of gram-positive cocci) were used as indicators of inhibition. Eleven anaerobic species were isolated from oral secretions. All isolates of Bacteroides melaninogenicus, the most commonly recovered species, consistently inhibited several species of indicator bacteria. Bacteroides fragilis, Bacteroides oralis, and Peptostreptococcus anaerobius had unprecictable inhibitory activity, whereas most of the other oral anaerobes were noninhibitory. The 42 clinical species were generally noninhibitory.