Academic literature on the topic 'Tannin-resistant bacteria'

ABSTRACT The effect of dietary condensed tannins (proanthocyanidins) on rat fecal bacterial populations was ascertained in order to determine whether the proportion on tannin-resistant bacteria increased and if there was a change in the predominant bacterial populations. After 3 weeks of tannin diets the proportion of tannin-resistant bacteria increased significantly (P < 0.05) from 0.3% ± 5.5% to 25.3% ± 8.3% with a 0.7% tannin diet and to 47.2% ± 5.1% with a 2% tannin diet. The proportion of tannin-resistant bacteria returned to preexposure levels in the absence of dietary tannins. A shift in bacterial populations was confirmed by molecular fingerprinting of fecal bacterial populations by denaturing gradient gel electrophoresis (DGGE). Posttreatment samples were generally still distinguishable from controls after 3.5 weeks. Sequence analysis of DGGE bands and characterization of tannin-resistant isolates indicated that tannins selected for Enterobacteriaceae and Bacteroides species. Dot blot quantification confirmed that these gram-negative bacterial groups predominated in the presence of dietary tannins and that there was a corresponding decrease in the gram-positive Clostridium leptum group and other groups. Metabolic fingerprint patterns revealed that functional activities of culturable fecal bacteria were affected by the presence of tannins. Condensed tannins of Acacia angustissima altered fecal bacterial populations in the rat gastrointestinal tract, resulting in a shift in the predominant bacteria towards tannin-resistant gram-negative Enterobacteriaceae and Bacteroides species.

ABSTRACTBacterial motility plays a key role in the colonization of surfaces by bacteria and the subsequent formation of resistant communities of bacteria called biofilms. Derivatives of cranberry fruit, predominantly condensed tannins called proanthocyanidins (PACs) have been reported to interfere with bacterial adhesion, but the effects of PACs and other tannins on bacterial motilities remain largely unknown. In this study, we investigated whether cranberry PAC (CPAC) and the hydrolyzable tannin in pomegranate (PG; punicalagin) affected the levels of motilities exhibited by the bacteriumPseudomonas aeruginosa. This bacterium utilizes flagellum-mediated swimming motility to approach a surface, attaches, and then further spreads via the surface-associated motilities designated swarming and twitching, mediated by multiple flagella and type IV pili, respectively. Under the conditions tested, both CPAC and PG completely blocked swarming motility but did not block swimming or twitching motilities. Other cranberry-containing materials and extracts of green tea (also rich in tannins) were also able to block or impair swarming motility. Moreover, swarming bacteria were repelled by filter paper discs impregnated with many tannin-containing materials. Growth experiments demonstrated that the majority of these compounds did not impair bacterial growth. When CPAC- or PG-containing medium was supplemented with surfactant (rhamnolipid), swarming motility was partially restored, suggesting that the effective tannins are in part acting by a rhamnolipid-related mechanism. Further support for this theory was provided by demonstrating that the agar surrounding tannin-induced nonswarming bacteria was considerably less hydrophilic than the agar area surrounding swarming bacteria. This is the first study to show that natural compounds containing tannins are able to blockP. aeruginosaswarming motility and that swarming bacteria are repelled by such compounds.

Plants, a rich source of therapeutic compounds because its tremendous applications in the pharmaceutical industry. To find a new and effective antimicrobial compound from the selected plant, the solvents like methanol, Ethanol, Chloroform, Hexane, Xylene, and water were used to evaluate systematically. In vitro antimicrobial activity was performed using Multi-Drug Resistant (MDR) clinical isolates by Kirby Bauer Method. Solvent extracts showed more antimicrobial activity compared to aqueous extracts of both plants. Phytochemical analysis of Piper betel leaves showed the presence of Glycoside, Tannin, Terpenoid, Coumarin, Flavonoid, and Phenol whereas Achyranthes aspera roots were lacking Phenol and Tannin. Thus, present studies suggest the medicinal use of bioactive components from traditional plants Piper betel and Achyranthes aspera in the treatment of various infectious diseases.

The genus Artemisia includes the biggest genus of Asteraceae has many healthful uses in human diseases. The present study was conducted to eva-luate in vitro antioxidant and antibacterial activities of field wormwood, Artemisia campestris L. growing wild in the easthern of Algeria. The aerial parts of the plant were dried at shade and extracted with acetone, ethyl acetate, methanol and water. Total phenolic, flavonoid, flavanol and flavone, tannin and anthocyanin contents of different extracts from the whole plant were determined. The obtained results indicated that the ethyl acetate extract possessed high phenolic, flavonoid, flavanol and flavone contents and exhibited good antioxidant activity by DPPH, FRAP, ß- carotene bleaching methods. However, acetone extract showed strong antiradical property against H2O2 and high tannin content. These findings provide evidence that the polyphenolic extract of A. campestris L. is a natural source of antioxidant against oxidative damage. A. campestris extracts were also tested in vitro for its antimicrobial potential against three strains of pathogenic bacteria, using the disk diffusion method. The extracts showed the best antibacterial effect for all microbial strains tested even those resistant to some antibiotics. Fractionation and characterization of A. campestris active components may enhance the pharmaceutical industry of new drugs against pathogenic bacteria.

AbstractThe development of multiple antibiotic–resistant bacteria has vastly depleted our repertoire of effective antibiotic chemotherapies. The development of multi-β-lactam-resistant strains are particularly concerning due to our previous reliance on this class of antibiotics because of their initial efficacy and broad-spectrum activity. With increases in extended-spectrum β-lactam-resistance and an expanded resistance to other classes of antibiotics, there is an urgent need for the development of effective new antibiotic therapies. Terminalia ferdinandiana is an endemic Australian plant known for its high antioxidant and tannin contents. T. ferdinandiana fruit and leaf extracts have strong antibacterial activity against a wide variety of bacterial pathogens. However, T. ferdinandiana extracts have not been tested against ESBL and MRSA antibiotic-resistant pathogens. An objective of this study was to screen T. ferdinandiana fruit and leaf extracts for bacterial growth inhibitory activity by disc diffusion assay against β-lactam-sensitive and -resistant E. coli strains and against methicillin-sensitive and -resistant S. aureus. The minimum inhibitory concentration (MIC) was quantified by liquid dilution techniques. The fruit methanolic extract, as well as the methanolic, aqueous, and ethyl acetate leaf extracts strongly inhibited the growth of the MRSA, with MICs as low as 223 µg/mL. In contrast, the extracts were ineffective inhibitors of ESBL growth. Metabolomic fingerprint analysis identified a diversity and relative abundance of tannins, flavonoids, and terpenoids, several of which have been reported to inhibit MRSA growth in isolation. All extracts were nontoxic in the Artemia nauplii and HDF toxicity assays, further indicating their potential for medicinal use.

Antimicrobial activities and phytochemical screening of leaves of Mikania micrantha was tested in laboratory against phytopathogenic fungi and human pathogenic bacteria. The leaves samples were extracted in distilled water and methanol. The crude extracts of leaves were assessed in-vitro for antimicrobial activity using different concentrations (50, 100, 150,200, and 250 mg/ml) against five fungal strains (viz. Sclerotium rolfsii, Phytopthora capsici, Alternaria brassicae, Fusarium oxysporum and Botrytis cinerea) and six bacterial strains (Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, Bacillus subtilis, Enterococcusfaecalis and Staphylococcus aureus). Antifungal activity was tested by Poison Food Technique and Linear Mycelium growth Reduction (LMGR) percentage was determined. In crude extractof M. micrantha, the highest LMGR percentage was found in F. oxysporum in both distilledwater and methanol extract. Antibacterial activity was carried out by Disc Diffusion method. In the crude leaf extract of M. micrantha Gram negative bacteria was found more resistant than Gram positive bacteria. Methanol extract was found more effective in determining the Zone of Inhibition for all the strains of bacteria in all the concentrations. The plant extracts were found more effective in showing antibacterial activity than antifungal activity. The phytochemicalscreening revealed that the selected species contained tannin, saponins, alkaloid, flavonoid, cardiac glycosides and terpenoids. This result supports the potential of this plant species used as a new chemotherapeutic drug.

Hati Tanah tuber (Angiopteris sp) is a plant part that is often used by Dayak tribes in Central Kalimantan as a medicine to heal wounds. This plant is known to contain flavonoid, saponin, tannin and catechol compounds which in previous studies have proven that ethanol extract of this plant can inhibit the growth of Staphylococcus aureus bacteria. Staphylococcus aureus is a Gram-positive bacterium that causes infection in wounds. Some of these strains of bacteria are resistant to available antibiotics. In this study two bases of ointment were used, namely, the bottom of the hydrocarbon ointment and the base of the water-soluble lotion. This study aims to determine the ointment formulation which can inhibit the growth of S. aureus bacteria. Plant extraction is done by the soxhletation method. The inhibitory test in this study uses a process of planting discs that contain active substances as the primary test material. The results showed that the base ointment formulation which could inhibit the growth of Staphylococcus aureus bacteria was an ointment formulation with a water-soluble base.

Objective: This study represents the first attempt to investigate the antimicrobial activity of Peganum harmala, and Trachyspermum ammi seeds extract against the isolated bacillary dysentery-causing microorganisms.Methods: T. ammi and P. harmala were extracted by 96% ethanol using Soxhlet apparatus. The extracts were screened for their phytochemical constituents. Their antimicrobial activity against the isolated dysentery-causing microorganisms was evaluated using the agar diffusion method.Results: The antimicrobial activity result showed that, the two isolated bacteria, Shigella flexneri, and Shigella dysenteriae were found to be sensitive to the extract of T. ammi seed with inhibition zones up to 25 mm, compared to the inhibition zone of 20 mm produced by Gentamycin standard drug, this is mainly due to the presence of the different phytochemical in the extract such as tannin, flavonoids, terpenoids which are well known for their antimicrobial effects. The two isolated bacteria were found to be insensitive (zero mm) to P. harmala extract, Amoxicillin, and Amoclan (Amoxicillin+clavulanic acid) standard drugs, this is due to the fact that, the phytochemicals constituents of P. harmala possess the antagonistic effect to each other’s. Addition to; these bacteria became resistant to both Amoxicillin and Amoclan.Conclusion: From the results it concludes, T. ammi seeds extract had a considerable level of antimicrobial activity against bacillary dysentery-causing microorganisms resistant to Amoxicillin and Amoxicillin+clavulanic acid drugs.

We investigate the chemical composition of aqueous and hydroethanolic extracts of Stryphnodendron adstringens by evaluating the total polyphenolic and tannin contents, antioxidant activity as well as marker compounds by UHPLC-MS. Through the in silico approach the molecular and pharmacokinetic parameters were predicted for the two major substances found in the extract, the pyrogallol (1) and chlorogenic acid (2). The antibacterial activity was verified by determining the MIC of the extracts on different bacterial strains. The inhibition zone diameter (ZD) of three different extracts of S. adstringens was studied, those with ZD>10mm proceeded to the determination of the MICs. The most active antimicrobial sample was S. adstringens ST3. The extracts of S. adstringens analyzed herein demonstrated not only high content of polyphenols and total tannins, but also antioxidant activity and activity against important bacterial pathogens like Streptococcus pneumoniae, Neisseria gonorrhoeae as well as against multiresistant bacteria such as MRSA (Methicillin-resistant Staphylococcus aureus) and Pseudomonas aeruginosa. The effects of S. adstringens extract on the phagocytosis and intracellular killing of Candida albicans and Candida. kefyr from two normal individuals were studied. We propose that the effect of S. adstringens on the neutrophils may be related to a possible mechanism for regulation functions in these cells.

Low availability and poor nutrient quality of tropical grasses result in low levels of animal production. Browse/shrub legumes such as mulga (Acacia sp.) and calliandra (Calliandra calothyrsus) can be used as supplements to improve animal production. However, their utilisation is limited by the presence of antinutritional compounds, such as tannins. Tannins are polyphenolic compounds that are capable of binding other nutrients to form stable complexes. Tannins comprise hydrolysable (HT) and condensed tannins (CT) with CTs being the major form found in the legumes. Their concentration in feeds determines their effect on animal production. Low levels of tannin (< 40 g.kg DM⁻¹) protect feed protein from degradation by rumen microbes, thereby increasing the amount of protein passing through the rumen, and reducing the potential for bloat. However, high concentrations of tannin retard animal production through the inhibition of enzyme activities of some rumen bacteria, decreasing the availability of protein and fibre, and reducing feed intake. Tannins in high concentrations also bind nutrients such as protein and carbohydrates; tannin-protein or tannin-carbohydrate complexes are difficult to digest by rumen microbes or by enzymes secreted by ruminants in the gastrointestinal tract. This decreases the availability of protein and carbohydrate for the animals, reducing feed intake and decrease animal production. Several methods have been developed to overcome tannin problems in livestock feeds with a focus on the use of biological treatments. Such treatments emphasise the involvement of rumen microorganisms residing in the rumen of feral animals or of animals adapted to feeds with high tannin contents. This approach resulted in the isolation of the tannin-tolerant bacteria, Streptococcus gallollyticus and Selenomonas ruminantium K2, from the rumen of feral goats. However, these bacteria, alone or in combination, were unable to mimic the effect of whole rumen fluid on tannin detoxification. These bacteria may not, therefore, be the only ruminal species that are resistant to, or degrade tannins. Other tannin-resistant (TR) bacteria may also exist in the rumen. Although each of these TR-bacteria may have specific characteristics, they may interact synergistically to promote digestion of tannin-containing browse legumes. Therefore, the present project was aimed at isolating TR-bacteria from the rumen contents of feral goats and camels, and studying their ecology. To achieve these objectives, the research project is divided into three sections as follows : 1. Optimising the method for extracting tannin from legume leaves and selecting the appropriate method to measure tannin content. 2. Isolating TR-bacteria in rumen fluid samples from feral goats and camels, and characterising them phenotypically and by molecular characterisation using restriction analysis of amplified 16S rDNA and 16S rDNA sequence analysis. 3. In vitro studies of dry matter (DM) disappearance of mulga and calliandra with populations of TR-bacteria grown in a monoculture or in a co-culture system. Extracts of condensed tannins (CTs) were used as substrates for isolating TR-bacteria from feral goat and camel rumen fluids. CTs were extracted from legumes using 70% acetone, and used as a substrate in bacterial enrichment studies. The amount of soluble tannin extracted from the samples varied among plant species with mulga containing less free tannin than calliandra. Factors such as processing methods (fresh, freeze-drying and oven-drying), or physical and chemical treatments (autoclaving and phenol extraction) are tested for their effect on yield of extractable tannin. Freeze-drying was selected for processing mulga and calliandra leaves before extraction of CT by the method of Terrill et al. (1992). Measurement of tannins using different methods yielded different values of extractable tannin from the same legume. Since vanillin-HCl, butanol-HCl and H₂SO₄ methods are based on different principles, the standard used, the solvents, and other factors were tested for each method. The H₂SO₄ method was selected to measure the amount of free tannin extracted from the legumes. This selection was made on the basis that the results were comparable to those produced by the butanol-HCl assay procedure, but the H₂SO₄ method would have less interference from water in the microbiology studies. The amount of extractable tannin was expressed as equivalents to quebracho tannins when 70% acetone was used to dissolve the tannin extracts and the standard. Twenty TR-bacteria were successfully isolated from the rumen fluid of feral goats and camels using extractable CT of freeze-dried mulga and calliandra, as well as hydrolysable tannin (tannic acid). These isolates were divided morphologically into several groups : Gram-positive cocci (Group 1), Gram-positive cocci/rods (Group 2 and 4), Gramnegative cocci (Group 3), Gram-negative curved rods (Group 5) and Gram-negative slender rods (Group 6). These bacteria were identified by physiological and biochemical characterisations, and API testing as Streptococcus sp. (Group 1), Lactobacillus sp. (Group 2 and 4), Selenomonas ruminantium (Group 5) and Butyrivibrio sp. (Group 6). A further identification using restriction analysis of amplified 16S rDNA with four restriction endonucleases (AluI, HaeIII, MspI and TaqI) characterised bacteria that belong to the Streptococcus sp. (Group 1) and Selenomonas ruminantium (Group 5). Confirmation of genera of other TR-bacteria was made after integrating the RFLP analysis with amplified 16S rDNA sequence analysis. This identified the bacteria as : Lactobacillus sp. (Group 2 and 4), and Butyrivibrio sp. (Group 6). The genus of Gram-negative coccus (Group 3) was identified as Escherichia (E. coli) coli; however, a further clarification is necessary for the identification Group 3 isolate. These results provide an example of phenotypic identification and molecular characterisations using restriction analysis of amplified 16S rDNA and 16S rDNA sequence analysis for identifying TR-isolates from feral goat and camel rumen fluids. The TR-bacteria had different capabilities of degrading mulga and calliandra as indicated by results of studies on in vitro DM degradability using monocultures of the TRbacteria. The highest DM degradabilities of both legumes were obtained in cultures inoculated with Butyrivibrio spp. (G23A and G53C), and S. gallolyticus. These TR-bacteria are the main TR-bacteria degrading mulga and calliandra. The other TR-bacteria, Lactobacillus spp. (G43C and G33A), E. coli (C43C) and Sel. ruminantium K2, used metabolic products from these main TR-bacteria. Co-culture between the main TR-bacteria (Butyrivibrio spp. (G23A and G53C) or S. gallolyticus) with the bacteria that utilize the metabolic products of tannin degradation (Lactobacillus spp. (G43C and G33A), E. coli (C43C) or Sel. ruminantium K2) could improve mulga and calliandra degradation. Calliandra leaves were more degraded than mulga leaves because calliandra leaves have smoother physical characteristics, and lower concentrations of fibrous components and protein/fibre bound tannins than mulga leaves. Grinding the sample leaves and incubating cultures for 48 h improved degradation of legume leaves; incubation for 48 h was also suitable for TR-bacteria to achieve optimum growth and enzyme secretions. TR-bacterial characteristics and populations, and the nature of legume leaves are important factors affecting degradation of legumes containing tannins. Factors associated with TR-bacterial characteristics are the presence and activity of enzymes for degrading nutrients and antinutrients from the legumes, the presence of substances protecting TRbacteria from the antinutrients present in the legume, and the bacterial growth characteristics during the period of legume degradation. All these factors, consequently, affect TR-bacterial populations in cultures that contain legumes with tannins. Factors related to the nature of legume leaves are the physical characteristics, nutrient composition and concentration, especially the fibrous compounds and the types of tannins or other antinutrients. It is concluded that Streptococcus gallollyticus and Selenomonas ruminantium are not the only tannin-resistant bacteria. Other bacteria from the rumen of feral goats and camels also tolerate tannins extracted from freeze-dried mulga and calliandra leaves, including Butyrivibrio sp., Lactobacillus sp. and E. coli (Gram-negative coccus). These bacteria differ in their abilities to digest the legumes. However, improvement in the legume digestibility can result from the interactions between these tannin resistant bacteria.
Thesis (M.Sc.) -- University of Adelaide, School of Agriculture, Food and Wine, 2012