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Sample records for norfloxacin antibiotic activity

  1. Effect of norfloxacin and moxifloxacin on melanin synthesis and antioxidant enzymes activity in normal human melanocytes.

    Science.gov (United States)

    Beberok, Artur; Wrześniok, Dorota; Otręba, Michał; Miliński, Maciej; Rok, Jakub; Buszman, Ewa

    2015-03-01

    Fluoroquinolone antibiotics provide broad-spectrum coverage for a number of infectious diseases, including respiratory as well as urinary tract infections. One of the important adverse effects of these drugs is phototoxicity which introduces a serious limitation to their use. To gain insight the molecular mechanisms underlying the fluoroquinolones-induced phototoxic side effects, the impact of two fluoroquinolone derivatives with different phototoxic potential, norfloxacin and moxifloxacin, on melanogenesis and antioxidant enzymes activity in normal human melanocytes HEMa-LP was determined. Both drugs induced concentration-dependent loss in melanocytes viability. The value of EC50 for these drugs was found to be 0.5 mM. Norfloxacin and moxifloxacin suppressed melanin biosynthesis; antibiotics were shown to inhibit cellular tyrosinase activity and to reduce melanin content in melanocytes. When comparing the both analyzed fluoroquinolones, it was observed that norfloxacin possesses greater inhibitory effect on tyrosinase activity in melanocytes than moxifloxacin. The extent of oxidative stress in cells was assessed by measuring the activity of antioxidant enzymes: SOD, CAT, and GPx. It was observed that norfloxacin caused higher depletion of antioxidant status in melanocytes when compared with moxifloxacin. The obtained results give a new insight into the mechanisms of fluoroquinolones toxicity directed to pigmented tissues. Moreover, the presented differences in modulation of biochemical processes in melanocytes may be an explanation for various phototoxic activities of the analyzed fluoroquinolone derivatives in vivo.

  2. Matricaria recutita extract associated with norfloxacin or cephalexin enhances the antimicrobial activity of these drugs against Staphylococcus aureus

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    Rodrigo Rafael Maia

    2017-05-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2017v30n2p25 Emergence of bacterial infections, including those associated with Staphylococcus aureus, brings up a need for searching new and more effective strategies for clinical treatment. The use of medicinal plants associated with conventional antibiotics may represent a therapeutic option. Currently, studies evidence the synergistic effect achieved by combining plant extracts with antibiotics. Our objective was evaluate the in vitro antimicrobial activity and bactericidal kinetics of Matricaria recutita extract (chamomile and its association with cephalexin and norfloxacin on clinical isolates of S. aureus from bovine origin, characterized as resistant. The tests were performed by method of dilution in solid medium to determine the Minimum Inhibitory Concentration (MIC. In both combinations of M. recutita extract with antibiotics norfloxacin and cephalexin, we observed MIC in dilution 1:64, corresponding to 8μg/mL of the antibiotic and 13.43 μg/mL of extract. Cephalexin associated with chamomile extract produced a effect of the combination in 75% of samples in their MIC. The combination of natural products frequently used by the population with the antibiotics tested in this study, could represent a therapeutic option for treatment of infections caused by S. aureus, as well as the prevention of the increasing development of resistance.

  3. Degradation of antibiotic norfloxacin in aqueous solution by visible-light-mediated C-TiO2 photocatalysis

    International Nuclear Information System (INIS)

    Chen, Meijuan; Chu, W.

    2012-01-01

    Highlights: ► Vis/C-TiO 2 process was employed to degrade norfloxacin for the first time. ► An original schematic diagram for deciphering the catalyst surface property was proposed. ► OH· radicals are verified to play a major role in the norfloxacin decomposition. ► Hole scavenger of ammonium did not show negative influence. ► Fluoride presented a unique restriction in the norfloxacin decay. - Abstract: A visible-light-mediated C-TiO 2 photocatalytic process (Vis/C-TiO 2 ) was employed to degrade antibiotic norfloxacin. The influences of catalyst dosage, initial probe compound concentration and solution pH levels on the decay performance and reaction kinetics were investigated and optimized. Based on the experimental results, an equation was established to predict the observed rate constant under neutral pH. In addition, the decay rate was accelerated under weak alkali in the presence of moderate OH − anions. Hydroxyl radical was confirmed to play a major role in the Vis/TiO 2 process, where in the presence of ·OH quencher and electron acceptor, retardation and improvement were found respectively. Furthermore, an original schematic diagram describing the surface property of C-TiO 2 was built and further verified, in which, NH 4 + cations normally served as hole scavengers showed a negligible effect because the adsorbed OH − formed a barrier for NH 4 + ions to approach the holes, and the F − anions presented a significant suppression on norfloxacin decay due to the formation of hydrogen bond (O-H⋯F) around the C-TiO 2 surface. Besides, the recycling and sedimentation tests justified that the Vis/C-TiO 2 process is a cost-effective and feasible way for wastewater treatment.

  4. Long-term effects of antibiotics, norfloxacin, and sulfamethoxazole, in a partial life-cycle study with zebrafish (Danio rerio): effects on growth, development, and reproduction.

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    Yan, Zhenhua; Lu, Guanghua; Ye, Qiuxia; Liu, Jianchao

    2016-09-01

    A partial life-cycle study with zebrafish (Danio rerio) was conducted to evaluate the long-term effects of antibiotics, norfloxacin (NOR) and sulfamethoxazole (SMX). A series of bio-endpoints correlated to the growth, development, and reproduction was assessed. The results showed that the body weight and the condition factor were depressed by SMX at 200 μg/L during the growth period. Meanwhile, the activities of metabolic enzyme (ethoxyresorufin O-deethylase, EROD) and antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT) were stimulated in all cases. The consequences of parental exposure to antibiotics for the next generation were also examined. The egg production of parents were depressed by the 200 μg/L NOR and SMX alone or in combination. Similarly, decreased hatching, survival, and enhanced development abnormality of the next generation also occurred after parental exposure to SMX at the highest concentration. The heartbeat however was not altered in all cases. Furthermore, there was no significant difference in the bio-endpoints between the combined and individual treatment in most cases, with the exception of lower EROD activity and egg production in the co-treatment. The results suggest that long-term exposure to NOR and SMX at environmentally relevant concentrations, individually and in a mixture, may not significantly pose a threat to the growth, development, and reproduction of zebrafish, and an adverse effect may be expected at high concentration.

  5. Study of the chemical chelates and anti-microbial effect of some metal ions in nanostructural form on the efficiency of antibiotic therapy "norfloxacin drug"

    Science.gov (United States)

    Refat, Moamen S.; El-Hawary, W. F.; Mohamed, Mahmoud A.

    2012-04-01

    This paper has reviewed the chemical and biological impact resulting from the interaction between norfloxacin (norH) antibiotic drug and two lanthanide (lanthanum(III) and cerium(III)) metal ions, which prepared in normal and nano-features. La(III) and Ce(III) complexes were synthesized with chemical formulas [La(nor)3]·3H2O and [Ce(nor)3]·2H2O. Lanthanum and cerium(III) ions coordinated toward norH with a hexadentate geometry. The norH acts as deprotonated bidentate ligand through the oxygen atom of carbonyl group and the oxygen atom of carboxylic group. Elemental analysis, FT-IR spectral, electrical conductivity, thermal analysis (TG/DTA), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurements have been used to characterize the mentioned isolated complexes. The Coats-Redfern and Horowitz-Metzger integral methods are used to estimate the kinetic parameters for the major successive steps detectable in the TG curve. The brightness side in this study is to take advantage for the preparation and characterization of single phases of La2O3 and CeO2 nanoparticles using urea as precursors via a solid-state decomposition procedure. The norH ligand in comparison with both cases (normal and nano-particles) of lanthanide complexes were screened against for antibacterial (Escherichia Coli, Staphylococcus Aureus, Bacillus subtilis and Pseudomonas aeruginosa) and antifungal (Aspergillus Flavus and Candida Albicans) activities. The highest antibacterial and antifungal activities data of the nano-particles complexes were observed with more potent than the free norH and normal lanthanide complexes.

  6. Adsorption of ciprofloxacin and norfloxacin from aqueous solution onto granular activated carbon in fixed bed column.

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    Darweesh, Teeba M; Ahmed, Muthanna J

    2017-04-01

    Carbonization of Phoenix dactylifera L stones followed by microwave K 2 CO 3 activation was adopted for preparation of granular activated carbon (KAC). High yield and favorable pore characteristics in terms of surface area and pore volume were reported for KAC as follows: 44%, 852m 2 /g, and 0.671cm 3 /g, respectively. The application of KAC as adsorbent for attraction of ciprofloxacin (CIP) and norfloxacin (NOR) was investigated using fixed bed systems. The effect of flow rate (0.5-1.5ml/min), bed height (15-25cm), and initial drug concentration (75-225mg/l) on the behavior of breakthrough curves was explained. The fixed bed analysis showed the better correlation of breakthrough data by both Thomas and Yoon-Nelson models. Inlet drug concentration was of greatest effect on breakthrough data compared to other fixed bed variables. Experimental and calculated breakthrough data were obtained for CIP and NOR adsorption on KAC, thus being important for design of fixed bed column. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Lethal/sublethal responses of Daphnia magna to acute norfloxacin contamination and changes in phytoplankton-zooplankton interactions induced by this antibiotic

    Science.gov (United States)

    Pan, Ying; Yan, Shi-Wei; Li, Ruo-Zhu; Hu, Yi-Wen; Chang, Xue-Xiu

    2017-01-01

    Although the well-known antibiotic norfloxacin (NOR) is recognized as an important environmental pollutant, little is known about its impacts on ecological processes, particularly on species interactions. In this paper, we quantified Daphnia magna (Crustacea, Cladocera) responses in mortality rate at lethal NOR concentrations (0, 25, 50, 100, 200, 300 and 400 mg L-1), and in heartbeat rate, swimming behavior and feeding rate (on the green alga Chlorella pyrenoidosa) at sublethal NOR concentrations (0, 25, 50 and 100 mg L-1) to determine the effects of this antibiotic in plankton systems. In 96-h-long lethal experiment, mortality rates of D. magna increased significantly with increasing NOR concentration and exposure time. In sublethal experiments, heartbeat rate decreased, while time ratio of vertical to horizontal swimming (TVH) and the duration of quiescence increased in D. magna individuals exposed to increasing NOR concentrations after 4 and 12 h of exposure. These collectively led to decreases in both average swimming ability and feeding rate, consistent with the positive relationship between average swimming ability and feeding rate. Overall, results indicate that, by affecting zooplankton heartbeat rate and behavior, NOR decreased feeding efficiency of D. magna even at low doses, therefore, it might seriously compromise ecosystem health and function.

  8. Modulation of the norfloxacin resistance in Staphylococcus aureus by Cordia verbenaceae DC.

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    Matias, Edinardo F F; Santos, Karla K A; Falcão-Silva, Vivyanne S; Siqueira-Junior, Jose P; Costa, Jose G M; Coutinho, Henrique D M

    2013-01-01

    Several chemical compounds isolated from natural sources have antibacterial activity and some enhance the antibacterial activity of antibiotics reversing the natural resistance of bacteria to certain antibiotics. In this study, the hexane and methanol extract of Cordia verbenaceae were assessed for antibacterial activity alone and combinated with norfloxacin against the Staphylococcus aureus strain SA1199B. The minimum inhibitory concentration (MIC) of extracts was assayed using microdilution assay and the modulatory activity was evaluated using plate diffusion assay. The MIC observed varied between 256 to >1024 μg/ml. However, the antibiotic activity of norfloxacin was enhanced in the presence of subinhibitory concentrations of hexane extract of C. verbenaceae (HECV). INTERPRETATIONS & CONCLUSIONS: Our results indicate that Cordia verbenaceae DC. can be a source of plant derived products with antibiotic modifying activity.

  9. Modulation of the norfloxacin resistance in Staphylococcus aureus by Cordia verbenaceae DC

    OpenAIRE

    Edinardo F.F Matias; Karla K. A Santos; Vivyanne S Falcão-Silva; José P Siqueira-Júnior; José G. M Costa; Henrique D.M Coutinho

    2013-01-01

    Background & objectives: Several chemical compounds isolated from natural sources have antibacterial activity and some enhance the antibacterial activity of antibiotics reversing the natural resistance of bacteria to certain antibiotics. In this study, the hexane and methanol extract of Cordia verbenaceae were assessed for antibacterial activity alone and combinated with norfloxacin against the Staphylococcus aureus strain SA1199B. Methods: The minimum inhibitory concentration (MIC) of ex...

  10. A synergistic effect of artocarpanone from Artocarpus heterophyllus L. (Moraceae) on the antibacterial activity of selected antibiotics and cell membrane permeability.

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    Septama, Abdi Wira; Xiao, Jianbo; Panichayupakaranant, Pharkphoom

    2017-01-01

    Artocarpanone isolated from Artocarpus heterophyllus L. (Moraceae) exhibits antibacterial activity. The present study investigated synergistic activity between artocarpanone and tetracycline, ampicillin, and norfloxacin, respectively, against methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa , and Escherichia coli . A broth microdilution method was used for evaluating antibacterial susceptibility. Synergistic effects were identified using a checkerboard method, and a bacterial cell membrane disruption was investigated by assay of released 260 nm absorbing materials following bacteriolysis. Artocarpanone exhibited weak antibacterial activity against MRSA and P. aeruginosa with minimum inhibitory concentrations values of 125 and 500 μg/mL, respectively. However, the compound showed strong antibacterial activity against E. coli (7.8 μg/mL). The interaction between artocarpanone and all tested antibiotics revealed indifference and additive effects against P. aeruginosa and E. coli (fractional inhibitory concentration index [FICI] values of 0.75-1.25). The combination of artocarpanone (31.2 μg/mL) and norfloxacin (3.9 μg/mL) resulted in synergistic antibacterial activity against MRSA, with an FICI of 0.28, while the interaction between artocarpanone and tetracycline, and ampicillin showed an additive effect, with an FICI value of 0.5. A time-kill assay also indicated that artocarpanone had a synergistic effect on the antibacterial activity of norfloxacin. In addition, the combination of artocarpanone and norfloxacin altered the membrane permeability of MRSA. These findings suggest that artocarpanone may be used to enhance the antibacterial activity of norfloxacin against MRSA.

  11. Degradation of fluoroquinolone antibiotics during ionizing radiation treatment and assessment of antibacterial activity, toxicity and biodegradability of the products

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    Tegze, Anna; Sági, Gyuri; Kovács, Krisztina; Homlok, Renáta; Tóth, Tünde; Mohácsi-Farkas, Csilla; Wojnárovits, László; Takács, Erzsébet

    2018-06-01

    This work aimed at investigating the ionizing radiation induced degradation of two fluoroquinolone antibiotics: norfloxacin and ciprofloxacin. At 0.1 mmol dm-3 concentration a low dose, 2 kGy was sufficient to degrade the initial molecules. However, despite of the high removal efficiency the degrees of both the mineralization and the oxidation were low, ∼10% and ∼25%, respectively. (The difference between the results obtained in norfloxacin and ciprofloxacin solutions was not statistically significant.) Broth microdilution tests carried out on Staphylococcus aureus evidenced removal of antibacterial activity in samples irradiated with 2 kGy. Acute toxicity determined on Vibrio fischeri bacteria showed increased toxicity at low doses indicating that the early degradation products were more toxic than the initial molecules. The results of biodegradation experiments performed in activated sludge have shown that the degradation products have become available to the metabolic processes of the microorganisms.

  12. A Synergistic effect of artocarpanone from Artocarpus heterophyllus Lam. (Moraceae on the antibacterial activity of some antibiotics and their effect on membrane permeability

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    Abdi Wira Septama

    2017-06-01

    Full Text Available Aim/backgrounds: Artocarpanone isolated from Artocarpus heterophyllus Lam. (Moraceae possesses antibacterial activity. The present study investigated any interaction between artocarpanone and some antibiotics including tetracycline, ampicillin and norfloxacin against Methicillin-resistant Staphylococcus aureus (MRSA, Pseudomonas aeruginosa and Escherichia coli, as well as determining any disruptive effect on bacterial membranes. Materials and methods: A broth microdilution method was used for the susceptibility assay. Any synergistic effect was determined using a checerboard method, and any membrane disruption effect was investigated using a bacteriolysis assay and a measurement of the released 260 nm absorbing materials. Results and discussion: Artocarpanone exhibited weak antibacterial activities against MRSA and P. aeruginosa with MIC values of 125 and 500 µg/mL, respectively. However, it showed the strong antibacterial activity against E. coli (7.8 µg/mL. The interaction between artcarpanone with all tested antibiotics against P. aeruginosa and E. coli only revealed indifference and additive effects (FICI values of 0.75-1.25. The interaction between artocarpanone (31.2 µg/mL and norfloxacin (3.9 µg/mL exhibited a synergistic antibacterial activity against MRSA, with a fractional inhibitory concentration index (FICI of 0.28, while the interaction between artocarpanone and tetracycline, and ampicillin showed an additive effect, with an FICI value of 0.5. A time kill assay also indicated that artocarpanone had a synergistic effect on the antibacterial activity of norfloxacin. In addition, a combination of artocarpanone and norfloxacin altered the membrane permeability of MRSA. Conclusion: These findings suggested that artocarpanone may be considered as an adjuvant to enhance the antibacterial activity of norfloxacin against MRSA. [J Complement Med Res 2017; 6(2.000: 186-191

  13. Biodegradation of norfloxacin by Penicillium frequentans isolated ...

    African Journals Online (AJOL)

    One norfloxacin-degrading fungi was isolated from soil contaminated by norfloxacin and preliminary identified as Penicillium frequentans. Indoor simulative degradation experiments were carried out to investigate the biodegradation kinetics of norfloxacin with or without NFX3 in soil. The results indicate that the ...

  14. Sucralfate reduces the gastrointestinal absorption of norfloxacin.

    OpenAIRE

    Parpia, S H; Nix, D E; Hejmanowski, L G; Goldstein, H R; Wilton, J H; Schentag, J J

    1989-01-01

    The effect of sucralfate on the bioavailability of norfloxacin after single 400-mg doses of norfloxacin was evaluated in eight healthy males. Subjects received each of the following treatments in random sequence: (i), norfloxacin, 400 mg alone; (ii) sucralfate, 1 g, concurrently with norfloxacin, 400 mg; and (iii) sucralfate, 1 g, followed by norfloxacin, 400 mg, 2 h later. One day before administration of treatments 2 and 3, 1 g of sucralfate was given at 7 a.m., 11 a.m., 5 p.m., and 10 p.m....

  15. Solubility behavior and biopharmaceutical classification of novel high-solubility ciprofloxacin and norfloxacin pharmaceutical derivatives.

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    Breda, Susana A; Jimenez-Kairuz, Alvaro F; Manzo, Ruben H; Olivera, María E

    2009-04-17

    The hydrochlorides of the 1:3 aluminum:norfloxacin and aluminum:ciprofloxacin complexes were characterized according to the Biopharmaceutics Classification System (BCS) premises in comparison with their parent compounds. The pH-solubility profiles of the complexes were experimentally determined at 25 and 37 degrees C in the range of pH 1-8 and compared to that of uncomplexed norfloxacin and ciprofloxacin. Both complexes are clearly more soluble than the antibiotics themselves, even at the lowest solubility pHs. The increase in solubility was ascribed to the species controlling solubility, which were analyzed in the solid phases at equilibrium at selected pHs. Additionally, permeability was set as low, based on data reported in the scientific literature regarding oral bioavailability, intestinal and cell cultures permeabilities and also considering the influence of stoichiometric amounts of aluminum. The complexes fulfill the BCS criterion to be classified as class 3 compounds (high solubility/low permeability). Instead, the active pharmaceutical ingredients (APIs) currently used in solid dosage forms, norfloxacin and ciprofloxacin hydrochloride, proved to be BCS class 4 (low solubility/low permeability). The solubility improvement turns the complexes as potential biowaiver candidates from the scientific point of view and may be a good way for developing more dose-efficient formulations. An immediate release tablet showing very rapid dissolution was obtained. Its dissolution profile was compared to that of the commercial ciprofloxacin hydrochloride tablets allowing to dissolution of the complete dose at a critical pH such as 6.8.

  16. Phytochemical study of Pilosocereus pachycladus and antibiotic-resistance modifying activity of syringaldehyde

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    Severino Gonçalves de Brito-Filho

    Full Text Available ABSTRACT Pilosocereus pachycladus F. Ritter, Cactaceae, popularly known as "facheiro", is used as food and traditional medicine in Brazilian caatinga ecoregion. The plant is used to treat prostate inflammation and urinary infection. The present work reports the first secondary metabolites isolated from P. pachycladus. Therefore, the isolated compound 4-hydroxy-3,5-dimethoxy benzaldehyde (syringaldehyde was evaluated as modulator of Staphylococcus aureus pump efflux-mediated antibiotic resistance. The isolation of compounds was performed using chromatographic techniques and the structural elucidation was carried out by spectroscopic methods. In order to evaluate syringaldehyde ability to modulate S. aureus antibiotic resistance, its minimum inhibitory concentrations (µg/ml was first determinate, then, the tested antibiotics minimum inhibitory concentrations were determined in the presence of the syringaldehyde in a sub-inhibitory concentration. The chromatographic procedures led to isolation of twelve compounds from P. pachycladus including fatty acids, steroids, chlorophyll derivatives, phenolics and a lignan. The syringaldehyde did not show any antibacterial activity at 256 µg/ml against S. aureus. On the other hand the compound was able to reduce the antibiotic concentration (tetracycline, norfloxacin, ethidium bromide required to inhibit the growth of drug-resistant bacteria, showing the ability of syringaldehyde of inhibiting the efflux pump on these bacteria.

  17. Lipid-polymer hybrid nanoparticles: Development & statistical optimization of norfloxacin for topical drug delivery system

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    Vivek Dave

    2017-12-01

    Full Text Available Poly lactic acid is a biodegradable, biocompatible, and non-toxic polymer, widely used in many pharmaceutical preparations such as controlled release formulations, parenteral preparations, surgical treatment applications, and tissue engineering. In this study, we prepared lipid-polymer hybrid nanoparticles for topical and site targeting delivery of Norfloxacin by emulsification solvent evaporation method (ESE. The design of experiment (DOE was done by using software to optimize the result, and then a surface plot was generated to compare with the practical results. The surface morphology, particle size, zeta potential and composition of the lipid-polymer hybrid nanoparticles were characterized by SEM, TEM, AFM, and FTIR. The thermal behavior of the lipid-polymer hybrid nanoparticles was characterized by DSC and TGA. The prepared lipid-polymer hybrid nanoparticles of Norfloxacin exhibited an average particle size from 178.6 ± 3.7 nm to 220.8 ± 2.3 nm, and showed very narrow distribution with polydispersity index ranging from 0.206 ± 0.36 to 0.383 ± 0.66. The surface charge on the lipid-polymer hybrid nanoparticles were confirmed by zeta potential, showed the value from +23.4 ± 1.5 mV to +41.5 ± 3.4 mV. An Antimicrobial study was done against Staphylococcus aureus and Pseudomonas aeruginosa, and the lipid-polymer hybrid nanoparticles showed potential activity against these two. Lipid-polymer hybrid nanoparticles of Norfloxacin showed the %cumulative drug release of 89.72% in 24 h. A stability study of the optimized formulation showed the suitable condition for the storage of lipid-polymer hybrid nanoparticles was at 4 ± 2 °C/60 ± 5% RH. These results illustrated high potential of lipid-polymer hybrid nanoparticles Norfloxacin for usage as a topical antibiotic drug carriers.

  18. Effect of sucralfate on absorption of norfloxacin and ofloxacin.

    OpenAIRE

    Lehto, P; Kivistö, K T

    1994-01-01

    The effect of sucralfate on the pharmacokinetics of norfloxacin and ofloxacin was assessed in two separate crossover studies with healthy volunteers. In both studies, eight subjects were randomized to one of the following three regimens: a 400-mg dose of norfloxacin or ofloxacin alone, norfloxacin or ofloxacin given simultaneously with sucralfate (1 g), or norfloxacin or ofloxacin given 2 h before sucralfate. Coadministration of sucralfate reduced the bioavailability of norfloxacin and ofloxa...

  19. Microencapsulation of norfloxacin in chitosan/chitosan oligosaccharides and its application in shrimp culture.

    Science.gov (United States)

    Lian, Ziru; Pan, Rong; Wang, Jiangtao

    2016-11-01

    Norfloxacin chitosan/chitosan oligosaccharide microcapsules (NCCM) were prepared by emulsion-chemical crosslinking method. The characteristics of obtained microcapsules were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy and release experiments. Cumulative release profile of norfloxacin from the chitosan microcapsules in natural seawater was measured and the controlled release of drugs was at a uniform rate in 48h. The chitosan microcapsules were applied onto the antibacterial study of the shrimp culture in natural seawater. It is observed that the seawater in the NCCM added groups was relatively clear and the biomass of Vibrio increased slowly in contrast to the control and norfloxacin groups. The inhibition rate of Vibrio in norfloxacin groups obvioursly decreased after the 5 th day, whereas, it remained high and stable during experiment period in NCCM groups. The results showed that the chitosan microcapsules as release materials have excellent antibacterial effects on Vibrio in the farming of Penaeus vannamei Boone. The controlled release could obviously reduce dosage of antibiotics and delivery times, and effectively improve the utilization rate of norfloxacin drugs for shrimps. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Construction and sequencing analysis of scFv antibody fragment derived from monoclonal antibody against norfloxacin (Nor155

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    J. Mala

    2017-06-01

    Full Text Available Norfloxacin belongs to the group of fluoroquinolone antibiotics which has been approved for treatment in animals. However, its residues in animal products can pose adverse side effects to consumer. Therefore, detection of the residue in different food matrices must be concerned. In this study, a single chain variable fragment (scFv that recognizes norfloxacin antibiotic was constructed. The cDNA was synthesized from total RNA of hybridoma cells against norfloxacin. Genes encoding VH and VL regions of monoclonal antibody against norfloxacin (Nor155 were amplified and size of VH and VL fragments was 402 bp and 363 bp, respectively. The scFv of Nor155 was constructed by an addition of (Gly4Ser3 as a linker between VH and VL regions and subcloned into pPICZαA, an expression vector of Pichia pastoris. The sequence of scFv Nor155 (GenBank No. AJG06891.1 was confirmed by sequencing analysis. The complementarity determining regions (CDR I, II, and III of VH and VL were specified by Kabat method. The obtained recombinant plasmid will be useful for production of scFv antibody against norfloxacin in P. pastoris and further engineer scFv antibody against fluoroquinolone antibiotics.

  1. The effect of iron plaque on uptake and translocation of norfloxacin in rice seedlings grown in paddy soil.

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    Yan, Dafang; Ma, Wei; Song, Xiaojing; Bao, Yanyu

    2017-03-01

    Although the role of iron plaque on rice root surface has been investigated in recent years, its effect on antibiotic uptake remains uncertain. In the study, pot experiment was conducted to investigate the effect of iron plaque on uptake and translocation of norfloxacin (adding 10 and 50 mg·kg -1 treatments) in rice seedlings grown in paddy soil. Iron plaque was induced by adding different amounts of Fe(II) in soil. The results showed that the presence of norfloxacin can decrease the amount of iron plaque induced. After rice with iron plaque induced, norfloxacin was mainly accumulated in iron plaque on root surface, followed by inside root, but its translocation from root to other rice tissues is not observed. Iron plaque played the role of a barrier for norfloxacin uptake into rice roots under high norfloxacin concentration of 50 mg·kg -1 , however not that under low concentration of 10 mg·kg -1 . And the barrier function was the most strongest with adding Fe(II) of 30 mg·kg -1 as combined action of iron plaque and rhizosphere effect. Fluorescence microscope analysis showed that norfloxacin mainly distributed in the outside of root cell, which showed its translocation as apoplastic pathway in rice. Comparing with non-rhizosphere, more norfloxacin was accumulated in rhizosphere soil. Maybe, strong root oxidization (high Eh values) induced more iron oxide formation in rhizosphere and on root surface, which led to norfloxacin's mobility towards to rhizosphere through its strong adsorption of iron oxides and then promoted its uptake by rice on root surface.

  2. Aminoguanidine hydrazones (AGH's) as modulators of norfloxacin resistance in Staphylococcus aureus that overexpress NorA efflux pump.

    Science.gov (United States)

    Dantas, Natalina; de Aquino, Thiago Mendonça; de Araújo-Júnior, João Xavier; da Silva-Júnior, Edeildo; Gomes, Ednaldo Almeida; Gomes, Antoniel Augusto Severo; Siqueira-Júnior, José Pinto; Mendonça Junior, Francisco Jaime Bezerra

    2018-01-25

    One of the promising fields for improving the effectiveness of antimicrobial agents is their combination with efflux pump inhibitors (EPIs), which besides expanding the use of existing antibiotics. The goal of this research was to evaluate a series of aminoguanidine hydrazones (AGH's, 1-19) as antibacterial agents and NorA efflux pump inhibitors in Staphylococcus aureus strain SA-1199B. Molecular modeling and docking studies were also performed in order to explain at the molecular level the interactions of the compounds with the generated NorA efflux pump model. The MICs of the antibiotic and ethidium bromide were determined by microdilution assay in absence or presence of a subinhibitory concentration of aminoguanidine hydrazones and macrophages viability was determined through MTT assay. Bioinformatic software Swiss-Model and AutoDock 4.2 were used to perform modeling and docking studies, respectively. As results, all AGH's were able to potentiate the action for the antibiotic norfloxacin, causing MIC's reduction of 16-fold and 32-fold to ethidium bromide. In the cell viability test, the concentration of 10 μg/mL showed better results than 90% and the concentration of 1000 μg/mL showed the lowest viability, reaching a maximum of 50% for the analyzed aminoguanidine hydrazones. Molecular docking studies showed that both norfloxacin and derivative 13 were recognized by the same binding site of NorA pump, suggesting a competitive mechanism. The present work demonstrated for the first time that AGH derivatives have potential to be putative inhibitors of NorA efflux pump, showing a promising activity as an antibacterial drug development. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. In vitro evaluation of the antibacterial potential and modification of antibiotic activity of the Eugenia uniflora L. essential oil in association with led lights.

    Science.gov (United States)

    Pereira, Nara L F; Aquino, Pedro E A; Júnior, José G A S; Cristo, Janyketchuly S; Vieira Filho, Marcos A; Moura, Flávio F; Ferreira, Najla M N; Silva, Maria K N; Nascimento, Eloiza M; Correia, Fabrina M A; Cunha, Francisco A B; Boligon, Aline A; Coutinho, Henrique D M; Matias, Edinardo F F; Guedes, Maria I F

    2017-09-01

    Due to the great biodiversity of its flora, Brazil provides combat tools against bacterial resistance with the utilization of natural products with vegetable origin. Therefore, the present study had as its objective to evaluate the antibacterial potential of the Eugenia uniflora essential oil (EuEO) in vitro, as well as to analyze the modulatory effect of the oil against antibiotics by gaseous contact and to compare them when associated with a LED apparatus. The chemical components were characterised by gas chromatography which revealed the presence of the isoflurane-germacrene, considered the major component (61.69%). The MIC obtained from the EuEO was ≥256 μg/mL for S. aureus and ≥1024 μg/mL for E. coli. When combined with antibiotics, the EuEO presented synergism reducing the MIC when associated, with the exception of gentamicin against E. coli, where an antagonistic effect was observed. The was an interference of the EuEO over the activity of ciprofloxacin when associated with red and blue LED lights, increasing the inhibition halos against S. aureus and E. coli. Norfloxacin presented similar results to ciprofloxacin against S. aureus bacteria. When combined, norfloxacin and the EuEO presented synergism against S. aureus, which did not occur in the combination with ciprofloxacin. Interference occurred only with blue light for E. coli. Thus, it was observed that the EuEO causes changes in the activity of antibiotics, the same occurring with the use of LED lights, without significant differences in the association of the oil and the lights with the antibiotics tested. Further research is needed to elucidate the modulatory effects of the EuEO, as well as its association with LED lights. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. 21 CFR 333.110 - First aid antibiotic active ingredients.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false First aid antibiotic active ingredients. 333.110... (CONTINUED) DRUGS FOR HUMAN USE TOPICAL ANTIMICROBIAL DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE First Aid Antibiotic Drug Products § 333.110 First aid antibiotic active ingredients. The product consists of any of...

  5. Antibiotics

    Science.gov (United States)

    Antibiotics are powerful medicines that fight bacterial infections. Used properly, antibiotics can save lives. They either kill bacteria or ... natural defenses can usually take it from there. Antibiotics do not fight infections caused by viruses, such ...

  6. Impact of chlortetracycline and sulfapyridine antibiotics on soil enzyme activities

    Science.gov (United States)

    Molaei, Ali; Lakzian, Amir; Datta, Rahul; Haghnia, Gholamhosain; Astaraei, Alireza; Rasouli-Sadaghiani, MirHassan; Ceccherini, Maria T.

    2017-10-01

    Pharmaceutical antibiotics are frequently used in the livestock and poultry industries to control infectious diseases. Due to the lack of proper guidance for use, the majority of administrated antibiotics and their metabolites are excreted to the soil environment through urine and feces. In the present study, we used chlortetracycline and sulfapyridine antibiotics to screen out their effects on dehydrogenase, alkaline phosphatase and urease activity. Factorial experiments were conducted with different concentrations of antibiotic (0, 10, 25 and 100 mg kg-1 of soil) mixed with soil samples, and the enzyme activity was measured at intervals of 1, 4 and 21 days. The results show that the chlortetracycline and sulfapyridine antibiotics negatively affect the dehydrogenase activity, but the effect of sulfapyridine decreases with time of incubation. Indeed, sulfapyridine antibiotic significantly affect the alkaline phosphatase activity for the entire three-time interval, while chlortetracycline seems to inhibit its activity within 1 and 4 days of incubation. The effects of chlortetracycline and sulfapyridine antibiotics on urease activity appear similar, as they both significantly affect the urease activity on day 1 of incubation. The present study concludes that chlortetracycline and sulfapyridine antibiotics have harmful effects on soil microbes, with the extent of effects varying with the duration of incubation and the type of antibiotics used.

  7. At the Nexus of Antibiotics and Metals: The Impact of Cu and Zn on Antibiotic Activity and Resistance.

    Science.gov (United States)

    Poole, Keith

    2017-10-01

    Environmental influences on antibiotic activity and resistance can wreak havoc with in vivo antibiotic efficacy and, ultimately, antimicrobial chemotherapy. In nature, bacteria encounter a variety of metal ions, particularly copper (Cu) and zinc (Zn), as contaminants in soil and water, as feed additives in agriculture, as clinically-used antimicrobials, and as components of human antibacterial responses. Importantly, there is a growing body of evidence for Cu/Zn driving antibiotic resistance development in metal-exposed bacteria, owing to metal selection of genetic elements harbouring both metal and antibiotic resistance genes, and metal recruitment of antibiotic resistance mechanisms. Many classes of antibiotics also form complexes with metal cations, including Cu and Zn, and this can hinder (or enhance) antibiotic activity. This review highlights the ways in which Cu/Zn influence antibiotic resistance development and antibiotic activity, and in so doing impact in vivo antibiotic efficacy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Norfloxacin degradation by Bacillus subtilis strains able to produce biosurfactants on a bioreactor scale

    Directory of Open Access Journals (Sweden)

    Jałowiecki Łukasz

    2017-01-01

    Full Text Available The discharge of antibiotics into the environment has become a major concern since this group of pharmaceuticals influence on microbial communities not only by its mode of action, but also because of the risk of a worldwide dispersal of antibiotic resistance genes (ARG. Antibiotics residues have been found in various environments such as waters, sediments, and soils. Moreover, most WWTPs are not designed to treat such kind of pollutants, which remain incompletely removed. Currently, biodegradation processes which involved bacterial strains with increased degradation capabilities is one of the most promising technique. The aim of this study was to evaluate the norfloxacin biodegradation potential of the three Bacillus subtilis strains named T-1, T’-1 and I’-1a on a bioreactor scale. The aerobic degradation was conducted in a 5-liter bioreactor on minimal salts medium in co-metabolic culture supplemented with glucose. The degradation rate of norfloxacin was determined with the HPLC technique. The surface tension was determined using ring method in order to observe the changes in biosurfactants production. Also, the biofilm formation abilities of the bacteria with two quantitative methods, crystal violet (CV method and TTC-based test and enzymes production were evaluated.

  9. Rapid optical determination of β-lactamase and antibiotic activity

    Science.gov (United States)

    2014-01-01

    Background The absence of rapid tests evaluating antibiotic susceptibility results in the empirical prescription of antibiotics. This can lead to treatment failures due to escalating antibiotic resistance, and also furthers the emergence of drug-resistant bacteria. This study reports a rapid optical method to detect β-lactamase and thereby assess activity of β-lactam antibiotics, which could provide an approach for targeted prescription of antibiotics. The methodology is centred on a fluorescence quenching based probe (β-LEAF – β-Lactamase Enzyme Activated Fluorophore) that mimics the structure of β-lactam antibiotics. Results The β-LEAF assay was performed for rapid determination of β-lactamase production and activity of β-lactam antibiotic (cefazolin) on a panel of Staphylococcus aureus ATCC strains and clinical isolates. Four of the clinical isolates were determined to be lactamase producers, with the capacity to inactivate cefazolin, out of the twenty-five isolates tested. These results were compared against gold standard methods, nitrocefin disk test for β-lactamase detection and disk diffusion for antibiotic susceptibility, showing results to be largely consistent. Furthermore, in the sub-set of β-lactamase producers, it was demonstrated and validated that multiple antibiotics (cefazolin, cefoxitin, cefepime) could be assessed simultaneously to predict the antibiotic that would be most active for a given bacterial isolate. Conclusions The study establishes the rapid β-LEAF assay for β-lactamase detection and prediction of antibiotic activity using S. aureus clinical isolates. Although the focus in the current study is β-lactamase-based resistance, the overall approach represents a broad diagnostic platform. In the long-term, these studies form the basis for the development of assays utilizing a broader variety of targets, pathogens and drugs. PMID:24708478

  10. Occurrence and risk assessment of four typical fluoroquinolone antibiotics in raw and treated sewage and in receiving waters in Hangzhou, China.

    Science.gov (United States)

    Tong, Changlun; Zhuo, Xiajun; Guo, Yun

    2011-07-13

    A sensitive liquid chromatography-fluorescence detection method, combined with one-step solid-phase extraction, was established for detecting the residual levels of the four typical fluoroquinolone antibiotics (ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) in influent, effluent, and surface waters from Hangzhou, China. For the various environmental water matrices, the overall recoveries were from 76.8 to 122%, and no obvious interferences of matrix effect were observed. The limit of quantitation of this method was estimated to be 17 ng/L for ciprofloxacin and norfloxacin, 20 ng/L for ofloxacin, and 27 ng/L for enrofloxacin. All of the four typical fluoroquinolone antibiotics were found in the wastewaters and surface waters. The residual contents of the four typical fluoroquinolone antibiotics in influent, effluent, and surface water samples are 108-1405, 54-429, and 7.0-51.6 ng/L, respectively. The removal rates of the selected fluoroquinolone antibiotics were 69.5 (ofloxacin), 61.3 (norfloxacin), and 50% (enrofloxacin), indicating that activated sludge treatment is effective except for ciprofloxacin and necessary to remove these fluoroquinolone antibiotics in municipal sewage. The risk to the aquatic environment was estimated by a ratio of measured environmental concentration and predicted no-effect concentration. At the concentrations, these fluoroquinolone antibiotics were found in influent, effluent, and surface waters, and they should not pose a risk for the aquatic environment.

  11. Silver enhances antibiotic activity against gram-negative bacteria.

    Science.gov (United States)

    Morones-Ramirez, J Ruben; Winkler, Jonathan A; Spina, Catherine S; Collins, James J

    2013-06-19

    A declining pipeline of clinically useful antibiotics has made it imperative to develop more effective antimicrobial therapies, particularly against difficult-to-treat Gram-negative pathogens. Silver has been used as an antimicrobial since antiquity, yet its mechanism of action remains unclear. We show that silver disrupts multiple bacterial cellular processes, including disulfide bond formation, metabolism, and iron homeostasis. These changes lead to increased production of reactive oxygen species and increased membrane permeability of Gram-negative bacteria that can potentiate the activity of a broad range of antibiotics against Gram-negative bacteria in different metabolic states, as well as restore antibiotic susceptibility to a resistant bacterial strain. We show both in vitro and in a mouse model of urinary tract infection that the ability of silver to induce oxidative stress can be harnessed to potentiate antibiotic activity. Additionally, we demonstrate in vitro and in two different mouse models of peritonitis that silver sensitizes Gram-negative bacteria to the Gram-positive-specific antibiotic vancomycin, thereby expanding the antibacterial spectrum of this drug. Finally, we used silver and antibiotic combinations in vitro to eradicate bacterial persister cells, and show both in vitro and in a mouse biofilm infection model that silver can enhance antibacterial action against bacteria that produce biofilms. This work shows that silver can be used to enhance the action of existing antibiotics against Gram-negative bacteria, thus strengthening the antibiotic arsenal for fighting bacterial infections.

  12. Bacteriostatic activity of various antibiotics after gamma-ray irradiation

    International Nuclear Information System (INIS)

    Fleurette, J.; Madier, S.; Transy, M.J.

    1975-01-01

    The purpose of the work described was to discover whether the antibiotics used in medicine can be sterilized by gamma rays; in this preliminary study, only the antimicrobic activity - the principal criterion for this type of medicament - was evaluated. Thirty-three products belonging to the various families of antibacterial and antifungic antibiotics were studied. The substances were irradiated in the dry state and in an aqueous solution, using a caesium-137 irradiator. The antibacterial and antifungic activity before and after irradiation was investigated by the method of diffusion in gelose. When irradiated in the dry state, 14 antibiotics preserve normal activity up to a dose of 10 Mrad; at doses between 5 and 10 Mrad, 15 other antibiotics are subject to a variable, but moderate, loss activity; and four register a slight loss of activity at a dose of 2.5 Mrad. In an aqueous solution all but two of the antibiotics suffer total loss of activity at a dose of 2.5 Mrad. As most commercial antibiotics are supplied in the dry state, gamma irradiation may be a useful sterilization process. However, preparations such as eye lotions, suspensions, ointments, etc. should be excepted

  13. The distribution and partitioning of common antibiotics in water and sediment of the Pearl River Estuary, South China.

    Science.gov (United States)

    Liang, Ximei; Chen, Baowei; Nie, Xiangping; Shi, Zhen; Huang, Xiaoping; Li, Xiangdong

    2013-09-01

    Antibiotics released into the aquatic environment play an important role in the spread of antibiotic resistance. In the Pearl River Estuary (PRE) and the coastal zone, the concentrations of antibiotics decreased from the Pearl River to the estuary, suggesting that antibiotics primarily originated from river tributaries and terrigenous sources. Within the PRE area, the concentrations of antibiotics in water were higher in the west coast than the east side, reflecting the high density of anthropogenic activities and hydraulic conditions along the west riverbank. Seasonal variations were also observed for most of detected antibiotics in water. The pseudo-partitioning coefficient of norfloxacin had a good correlation with the TOC content of sediments, as did erythromycin-H2O with the pH of water. The results suggest that environmental conditions can significantly affect the distribution of antibiotics between water and sediment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Cryptic antifungal compounds active by synergism with polyene antibiotics.

    Science.gov (United States)

    Kinoshita, Hiroshi; Yoshioka, Mariko; Ihara, Fumio; Nihira, Takuya

    2016-04-01

    The majority of antifungal compounds reported so far target the cell wall or cell membrane of fungi, suggesting that other types of antibiotics cannot exert their activity because they cannot penetrate into the cells. Therefore, if the permeability of the cell membrane could be enhanced, many antibiotics might be found to have antifungal activity. We here used the polyene antibiotic nystatin, which binds to ergosterol and forms pores at the cell membrane, to enhance the cellular permeability. In the presence of nystatin, many culture extracts from entomopathogenic fungi displayed antifungal activity. Among all the active extracts, two active components were purified and identified as helvolic acid and terramide A. Because the minimum inhibitory concentration of either compound was reduced four-fold in the presence of nystatin, it can be concluded that this screening method is useful for detecting novel antifungal activity. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. Deoxyribonucleoside kinases activate nucleoside antibiotics in severely pathogenic bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Shannon, O.; Clausen, A.R.

    2007-01-01

    Common bacterial pathogens are becoming progressively more resistant to traditional antibiotics, representing a major public-health crisis. Therefore, there is a need for a variety of antibiotics with alternative modes of action. In our study, several nucleoside analogs were tested against pathog...... alternative for combating pathogenic bacteria.......Common bacterial pathogens are becoming progressively more resistant to traditional antibiotics, representing a major public-health crisis. Therefore, there is a need for a variety of antibiotics with alternative modes of action. In our study, several nucleoside analogs were tested against...... pathogenic staphylococci and streptococci. We show that pyrimidine-based nucleoside analogs, like 3'-azido-3'-deoxythymidine (AZT) and 2',2'-difluoro-2'deoxycytidine (gemcitabine), are specifically activated by the endogenous bacterial deoxyribonucleoside kinases, leading to cell death. Deoxyribonucleoside...

  16. Synthesis and Spectral Study of Novel Norfloxacin Derivatives

    Directory of Open Access Journals (Sweden)

    Pradeep Yadav

    2008-01-01

    Full Text Available Reaction of [1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl-quinolone-3-carboxylic acid (norfloxacin with thiazole / benzothiazole diazonium chloride to get new piperazine substituted norfloxacin derivative. These norfloxacin derivatives were further condensed with various β-diketone to get novel acid derivatives of 1-Ethyl-6-fluoro-4-oxo-7- [4 (thiazol-2-yldiazenyl-piperzin-1-yl]-1,4-dihydro-quinoline-3-carboxylic acid (6a-e and 7-(4-(benzo[d]thiazol-2-yldiazenylpiperazin-1-yl-1-ethyl-6-fluoro-4-oxo-1, 4-dihydroquinoline-3-carboxylic acid (6 f-j. Structures of these compounds were established on the basis of spectral studies viz. IR, 1H NMR etc.

  17. Occurrence, distribution, and potential sources of antibiotics pollution in the water-sediment of the northern coastline of the Persian Gulf, Iran.

    Science.gov (United States)

    Kafaei, Raheleh; Papari, Fatemeh; Seyedabadi, Mohammad; Sahebi, Soleyman; Tahmasebi, Rahim; Ahmadi, Mehdi; Sorial, George A; Asgari, Ghorban; Ramavandi, Bahman

    2018-06-15

    Occurrence and frequency of six most prescribed antibiotics (tetracycline, norfloxacin, azithromycin, anhydro erythromycin, cephalexin, and amoxicillin) were assessed in three wastewater treatment plants (WWTPs), and in water and sediments of the Persian Gulf at Bushehr coastline, Iran. The antibiotics concentration in the influent and effluent of septic tank (the hospital WWTP), activated sludge (the hospital WWTP), and stabilization pond (municipal WWTP) ranged between 7.89 and 149.63, 13.49-198.47, 6.55-16.37 ng/L, respectively. Conventional treatment resulted in incomplete removal of most of the studied antibiotics. Furthermore, the activated sludge was more effective in terms of antibiotic elimination compared to the stabilization pond or septic tank. The mean concentration of antibiotics ranged 1.21-51.50 ng/L in seawater and 1.40-25.32 ng/g in sediments during summer and winter. Norfloxacin was the dominant detected antibiotic in seawater, sediments, and influent of two hospital WWTPs. Seasonal comparisons showed significant differences for erythromycin and amoxicillin concentrations in seawater. Spatial variation indicated the role of physicochemical properties on distribution of antibiotics in seawater and sediments. The results emphasize the need to pay attention to antibiotic contamination in water and sediments of the Persian Gulf. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Anti-tuberculosis activity of -lactam antibiotics: prospects for the ...

    African Journals Online (AJOL)

    This review is prepared to show results on the anti-TB activity of -lactam antibiotics. -Lactams are among the oldest drugs with little or no side effects. Both in vitro studies and clinical data indicate that -lactams have a promising activity for use in the management of MDR-TB. More studies are required to define the interaction ...

  19. Metabolic Activity Interferometer: A Powerful Tool for Testing Antibiotics

    Directory of Open Access Journals (Sweden)

    Rachel R. P. Machado

    2012-01-01

    Full Text Available It is demonstrated that the efficiency of antibiotics can be tested using an interferometric method. Two antibiotics were used as models to show that an interferometric method to monitor the metabolic activity of slowly growing bacteria can be a safer method to judge antimicrobial properties of substances than conventional methods. The susceptibility of Mycobacterium bovis to hexane extract of Pterodon emarginatus and to the well-known antibiotic rifampicin was tested with the interferometric method and with the conventional microplate method. The microplate method revealed a potential activity of hexane extract against M. bovis. However, the interferometric method showed that the action of this substance is rather limited. Also in the case of rifampicin, the interferometric method was able to detect resistant bacteria.

  20. Effect of norfloxacin therapy for acute, uncomplicated lower urinary tract infection on vaginal Candida prevalence.

    Science.gov (United States)

    Rocha, Rodrigo M; Zanni, Pâmela C M Delvas; de Souza Bonfim-Mendonça, Patrícia; Gimenes, Fabrícia; Alczuk, Silvia S Dantas; Svidzinski, Terezinha I Estivalet; Consolaro, Márcia E Lopes

    2016-05-01

    Acute uncomplicated lower urinary tract infections (UTI) and vulvovaginal candidiasis (VVC) both occur frequently in women. Although VVC is believed to commonly occur after antibiotic therapy, few studies have demonstrated this association. Thus, the aim of the study was to estimate the prevalence of colonization by Candida spp. and VVC after norfloxacin (NOR) use for UTI and the effects on the vaginal microbiota and inflammatory process. This was a prospective cohort study of women with culture-proven UTI who were treated with NOR (antibiotic group). The control group consisted of women with noninfectious diseases or in preventive care. Candida vaginal infections were monitored both clinically and mycologically at baseline and at the follow-up evaluation. All women showed UTI remission after NOR treatment, and no woman in either group, antibiotic and control, showed symptoms of VVC. Both groups showed similar ratios of a positive Candida culture at baseline (6.7 % and 12.8 %, respectively) and at follow-up (3.3 % and 8.5 %, respectively) (p = 0.2768 and p = 0.5035, respectively). The antibiotic group showed no increased risk of Candida colonization or VVC after NOR treatment compared with the control group [odds ratio (OR) 0.556, 95 % confidence interval (CI) 0.2407-10.05]. NOR was effective for UTI treatment, did not increase the risk of vaginal colonization by Candida or VVC, and did not lead to major disturbances of the vaginal microbiota.

  1. Sorption of norfloxacin, sulfamerazine and oxytetracycline by KOH-modified biochar under single and ternary systems.

    Science.gov (United States)

    Luo, Jiwei; Li, Xue; Ge, Chengjun; Müller, Karin; Yu, Huamei; Huang, Peng; Li, Jiatong; Tsang, Daniel C W; Bolan, Nanthi S; Rinklebe, Jörg; Wang, Hailong

    2018-05-08

    Pollution of water by single antibiotics has been investigated in depth. However, in reality, a wide range of different contaminants is often mixed in the aquatic environment (contaminant cocktail). Here, single and competitive sorption dynamics of ionizable norfloxacin (NOR), sulfamerazine (SMR) and oxytetracycline (OTC) by both pristine and modified biochars were investigated. Sorption kinetics of the three antibiotics was faster in ternary-solute than single-solute system. Sorption efficiency was enhanced in the competitive system for NOR by the pristine biochar, and for OTC by both the pristine biochar and the modified biochar, while SMR sorption by the pristine biochar and the KOH-modified biochar was inhibited. Sorption was governed by electrostatic interactions, π-π EDA and H-bonds for antibiotics sorption by biochar. SMR and OTC sorption by biochar was influenced by cation bridging and surface complexation, respectively. This research finding will guide the development of treatment procedures for water polluted by multiple antibiotics. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Antibiotic activity of two Anabaena species against four fish ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... New antibiotics with high activity and without side effects for human and for .... doses, and n = the total number of used mice. Statistical .... extract of Anabaena variabilis on mice. Dose (mg/kg) ... Tetranychidae). International Conference for Development and the .... Elsevier Scientific, New York. 26. JE Grady,.

  3. Distribution, diversity, and activity of antibiotic-producing Pseudomonas spp.

    NARCIS (Netherlands)

    Souza, de J.T.

    2002-01-01

    Bacteria of the genus Pseudomonas are potential biocontrol agents of plant diseases caused by various fungi and oomycetes. Antibiotic production is an important trait responsible for the activity of several Pseudomonas

  4. Vancomycin-resistant enterococci: validation of susceptibility testing and in vitro activity of novel antibiotics

    DEFF Research Database (Denmark)

    Rathe, Mathias; Lise, Kristensen,; Ellermann-Eriksen, Svend

    Vancomycin-resistant enterococci: validation of susceptibility testing and in vitro activity of novel antibiotics......Vancomycin-resistant enterococci: validation of susceptibility testing and in vitro activity of novel antibiotics...

  5. Potentiation of antibiotic activity by Eugenia uniflora and Eugenia jambolanum.

    Science.gov (United States)

    Coutinho, Henrique D M; Costa, José G M; Falcão-Silva, Vivyanne S; Siqueira-Júnior, José P; Lima, Edeltrudes O

    2010-08-01

    This is the first report about the modifying antibiotic activity of Eugenia uniflora L. and Eugenia jambolanum L. In this study the ethanol extract of E. uniflora and E. jambolanum was tested for their antimicrobial activity against strains of Escherichia coli. The growth of the two strains of E. coli bacteria tested was not inhibited in a clinically relevant form by the extract. The minimal inhibitory concentration was >or=1,024 microg/mL for both strains of E. coli assayed. Synergism between this extract and gentamicin was demonstrated. In the same extract synergism was observed between chlorpromazine and kanamycin and between amikacin and tobramycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. It is therefore suggested that extracts from E. uniflora L. and E. jambolanum L. could be used as a source of plant-derived natural products with modifying antibiotic activity to gentamicin.

  6. Vanillin selectively modulates the action of antibiotics against resistant bacteria.

    Science.gov (United States)

    Bezerra, Camila Fonseca; Camilo, Cicera Janaine; do Nascimento Silva, Maria Karollyna; de Freitas, Thiago Sampaio; Ribeiro-Filho, Jaime; Coutinho, Henrique Douglas Melo

    2017-12-01

    The treatment of infections caused by microorganisms that are resistant to antibiotics represent one of the main challenges of medicine today, especially due to the inefficacy of long-term drug therapy. In the search for new alternatives to treat these infections, many researchers have been looking for new substances derived from natural products to replace, or be used in combination with conventional antibiotics. Vanillin is a phenolic compound whose antimicrobial activity has been used in the elimination of pathogens present in fruits and vegetables. However, its antibacterial and modulating properties remain to be characterized. Therefore, this work aimed to evaluate the antibacterial activity and analyze the modulator activity of vanillin in association with conventional antibiotics. The antimicrobial activity of vanillin was evaluated using the microdilution method to determine the Minimum Inhibitory Concentration (MIC) Standard strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and multi-resistant strains of Escherichia coli 06, Staphylococcus aureus 10, Pseudomonas aeruginosa 24 were used in this study. The antibiotic modulating effect was analyzed by combining vanillin with Norfloxacin, Imipenem, Gentamicin, Erythromycin and Tetracycline against the following multiresistant bacteria strains: Escherichia coli 06, Staphylococcus aureus 10 and Pseudomonas aeruginosa 24. Data were analyzed using the ANOVA test of two tracks followed by the post hoc Bonferroni test. Vanillin presented CIMs ≥1024μg/mL against all tested strains demonstrating that it did not present significant antibacterial activity. However, modulated the activity of gentamicin and imipenem against S. aureus and E. coli, causing a synergistic effect, but did not affect the activity of norfloxacin, tetracycline and erythromycin against these same microorganisms. A synergistic effect was also obtained from the association of vanillin with norfloxacin against P

  7. Enhancement of antibiotic activity by Cordia verbenacea DC

    OpenAIRE

    Matias, Edinardo F.F.; Santos, Karla K. A.; Almeida, Thiago S.; Costa, José G.M. da; Coutinho, Henrique D.M.

    2010-01-01

    Escherichia coli is known to produce enterotoxins whose properties and its role in diarrheal disease has been extensively investigated. Some species of Staphylococcus are often recognized as etiological agents of many animal and human opportunistic infections. This study is the first test of change in resistance of antibiotic activity by Cordia verbenacea DC. against multiresistant strains of Escherichia coli and Staphylococcus aureus. In this study, the hexane and methanol extract of Cordia ...

  8. Tetracyclines function as dual-action light-activated antibiotics.

    Directory of Open Access Journals (Sweden)

    Ya He

    Full Text Available Antimicrobial photodynamic inactivation (aPDI employs photosensitizing dyes activated by visible light to produce reactive oxygen species. aPDI is independent of the antibiotic resistance status of the target cells, and is thought unlikely to produce resistance itself. Among many PS that have been investigated, tetracyclines occupy a unique niche. They are potentially dual-action compounds that can both kill bacteria under illumination, and prevent bacterial regrowth by inhibiting ribosomes. Tetracycline antibiotics are regarded as bacteriostatic rather than bactericidal. Doxycycline (DOTC is excited best by UVA light (365 nm while demeclocycline (DMCT can be efficiently activated by blue light (415 nm as well as UVA. Both compounds were able to eradicate Gram-positive (methicillin-resistant Staphylococcus aureus and Gram-negative (Escherichia coli bacteria (>6 log(10 steps of killing at concentrations (10-50μM and fluences (10-20J/cm2. In contrast to methylene blue, MB plus red light, tetracyclines photoinactivated bacteria in rich growth medium. When ~3 logs of bacteria were killed with DMCT/DOTC+light and the surviving cells were added to growth medium, further bacterial killing was observed, while the same experiment with MB allowed complete regrowth. MIC studies were carried out either in the dark or exposed to 0.5mW/cm2 blue light. Up to three extra steps (8-fold increased antibiotic activity was found with light compared to dark, with MRSA and tetracycline-resistant strains of E. coli. Tetracyclines can accumulate in bacterial ribosomes, where they could be photoactivated with blue/UVA light producing microbial killing via ROS generation.

  9. Sugar-Grafted Cyclodextrin Nanocarrier as a "Trojan Horse" for Potentiating Antibiotic Activity.

    Science.gov (United States)

    Li, Min; Neoh, Koon Gee; Xu, Liqun; Yuan, Liang; Leong, David Tai; Kang, En-Tang; Chua, Kim Lee; Hsu, Li Yang

    2016-05-01

    The use of "Trojan Horse" nanocarriers for antibiotics to enhance the activity of antibiotics against susceptible and resistant bacteria is investigated. Antibiotic carriers (CD-MAN and CD-GLU) are prepared from β-cyclodextrin grafted with sugar molecules (D-mannose and D-glucose, respectively) via azide-alkyne click reaction. The sugar molecules serve as a chemoattractant enticing the bacteria to take in higher amounts of the antibiotic, resulting in rapid killing of the bacteria. Three types of hydrophobic antibiotics, erythromycin, rifampicin and ciprofloxacin, are used as model drugs and loaded into the carriers. The minimum inhibitory concentration of the antibiotics in the CD-MAN-antibiotic and CD-GLU-antibiotic complexes for Gram-negative Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii strains, and a number of Gram-positive Staphylococcus aureus strains, including the methicillin-resistant strains (MRSA), are reduced by a factor ranging from 3 to >100. The CD-MAN-antibiotic complex is also able to prolong the stability of the loaded antibiotic and inhibit development of intrinsic antibiotic resistance in the bacteria. These non-cytotoxic sugar-modfied nanocarriers can potentiate the activity of existing antibiotics, especially against multidrug-resistant bacteria, which is highly advantageous in view of the paucity of new antibiotics in the pipeline.

  10. Antibiotic activity of Plectranthus ornatus Codd., a Traditional Medicinal Plant

    Directory of Open Access Journals (Sweden)

    FERNANDA R. NASCIMENTO

    2017-10-01

    Full Text Available ABSTRACT The dichloromethane extract of Plectranthus ornatus Codd., a tradicional medicinal plant, showed antibiotic activity with minimum inhibitory concentration (MIC values of 0.4 mg.mL-1 and 100 percent of biofilm inhibition against Staphylococcus aureus strains isolated from animals with mastitis infections. Based on these antibacterial activities, in addition to ethnopharmacological reports from healing men and farmers in Brazil, an herbal soap was produced from this active extract and was tested both in vitro and in vivo. In vivo assays conducted on these herbal soaps led to results similar to those previously conducted with the active extract. These results indicated the great potential of this plant for use as an excipient by preparing herbal antibacterial soaps as an alternative veterinary medicine aimed at controlling bovine mastitis infections on small Brazilian farms.

  11. Structure, toxicity and antibiotic activity of gramicidin S and derivatives

    NARCIS (Netherlands)

    J.W. Swierstra (Jasper); V. Kapoerchan; A. Knijnenburg; A.F. van Belkum (Alex); M. Overhand

    2016-01-01

    textabstractDevelopment of new antibiotics is declining whereas antibiotic resistance is rising, heralding a post-antibiotic era. Antimicrobial peptides such as gramicidin S (GS), exclusively topically used due to its hemolytic side-effect, could still be interesting as therapeutic compounds. By

  12. Antimicrobial Activity and Antibiotic Sensitivity of Three Isolates of Lactic Acid Bacteria From Fermented Fish Product, Budu

    Directory of Open Access Journals (Sweden)

    Liasi, S. A.

    2009-01-01

    Full Text Available Three isolates of lactic acid bacteria (LAB from the fermented food product, Budu, were identified as genus lactobacillus (Lactobacillus casei LA17, Lactobacillus plantarum LA22 and L. paracasei LA02, and the highest population was Lb. paracasei LA02. The antibacterial agent produced by the isolates inhibited the growth of a range of gram-positive and gram-negative microorganisms. Antimicrobial sensitivity test to 18 different types of antibiotic were evaluated using the disc diffusion method. Inhibition zone diameter was measured and calculated from the means of five determinations and expressed in terms of resistance or susceptibility. All the LAB isolates were resistant to colestin sulphate, streptomycin, amikacin, norfloxacin, nalidixic acid, mecillinam, sulphanethoxazole/ trimethoprim, kanamycin, neomycin, bacitracin and gentamycin but susceptible to erythromycin, penicillin G, chloramphenicol, tetracycline, ampicillin and nitrofurantion.

  13. BIOAVAILABILITY AND PHARMACOKINETICS OF NORFLOXACIN AFTER INTRAMUSCULAR ADMINISTRATION IN GOATS

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    WAJEEHA, F. H. KHAN AND I. JAVED

    2006-01-01

    Full Text Available Bioavailability and pharmacokinetics of two commercially available preparations of norfloxacin i.e. A (imported and B (locally prepared were determined in six healthy female goats after single intramuscular administration @ 5 mg/kg b.wt following crossover study design. The blood samples collected at 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8 and 12 hours postmedication were also analysed for drug concentration by microbiological assay. Results revealed that preparation A showed higher (p<0.05 plasma drug levels than the preparation B at 1, 3, 6 and 8 hours after medication. Among bioavailability parameters AUC (g.h/ml and relative bioavailability (F% were higher for preparation A than the preparation B, while other parameters did not differ between the two preparations. Similarly, various pharmacokinetic parameters did not show any statistical difference between preparation A and B. The study revealed comparable elimination kinetics but different bioavailability of two commercial preparations of norfloxacin. It is concluded from the study that for optimal dosage regimen of drugs, the bioequivalence studies and kinetic behavior of the drugs are of paramount importance.

  14. The antibiotic activity of some Brazilian medicinal plants

    Directory of Open Access Journals (Sweden)

    Maria R. Ferreira de Lima

    Full Text Available The antibiotic activities of the ethanol extracts from 16 species of plants used in Brazilian folk medicine have been determined against Staphylococcus aureus, Micrococcus flavus, Bacillus cereus, B. subtilis, Salmonella enteretidis, Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Serratia marcescens, Mycobacterium phlei, M. smegmatis and M. fortuitum, and the yeasts Candida albicans and C. krusei. Among 32 extracts assayed, only those from Lafoensia pacari and Pterodon polygalaeflorus showed activity against the bacterial strains, and none were active against the yeasts. The ethanolic extract from the leaves of L. pacari showed minimum inhibitory concentration (MIC values of 312.5 to 2500, 250, 625 and 1250 mg/mL, respectively, against eight different Gram-positive strains of Staphylococcus aureus, the Gram-negative Proteus mirabilis and the acid-fast bacilli Mycobacterium phlei, M. fortuitum and M. smegmatis. The ethanolic extract from the stem of L. pacari showed an MIC value of 625 mg/mL against S. aureus. Chemical analysis revealed that the crude extracts contained tannins, steroids, phenols, flavonoids, triterpenes and saponins: the activities were sufficiently high to present the possibility of future identification of the active components by bioassay-guided fractionation and purification.

  15. Effects of oxytetracycline, tylosin, and amoxicillin antibiotics on specific methanogenic activity of anaerobic biomass

    OpenAIRE

    Mohammad Mehdi Amin; Hassan Hashemi; Afshin Ebrahimi; Asghar Ebrahimi

    2012-01-01

    Aims: The purpose of this study was to survey the antibiotics effects of oxytetracycline, tylosin, and amoxicillin on anerobic wastewater treatment process. Materials and Methods: To evaluate the inhibitory antibiotics amoxicillin, tetracycline, and tylosin on biomass activity, specific methanogenic activity (SMA) using anerobic biomass batch; into 120 ml vials: 30 ml biomass and 70 ml substrate including volatile fatty acids, mainly acetic acid and various concentrations of antibiotics we...

  16. A preliminary study on the phytoremediation of antibiotic contaminated sediment.

    Science.gov (United States)

    Hoang, Thuy Thi Thanh; Tu, Loan Thi Cam; Le Nga, Phi; Dao, Quoc Phu

    2013-01-01

    In Vietnam's coastal wetlands, fluoroquinolones, a widely used class of antibiotics in shrimp farming, are frequently detected in sediments of former shrimp farms. This phenomenon could lead to negative impacts on the aquatic ecosystem, since the antibiotic residues could induce changes in the microorganism communities of the water body. The potential of native wetland plants (Acrostichum aureum L. and Rhizophora apiculata Blume Fl. Javae) for phytoremediation of fluoroquinolones (ciprofloxacin and norfloxacin) was investigated. The half-life for each antibiotic was estimated at approximately 10 days in the planted sediment. With respect to the accumulation of ciprofloxacin and norfloxacin in plants, these antibiotics were found mainly in roots. Antibiotic translocation from root to stem and leaves occurred at a low rate. The results showed that A. aureum and R. apiculata can be valuable for the phytoremediation of antibiotic-contaminated sediments. Additionally, the initialfindings of the presence of resistant bacteria indicated that bacteria could play a role in facilitating the phytodegradation.

  17. Tannic Acid as a Potential Modulator of Norfloxacin Resistance in Staphylococcus Aureus Overexpressing norA.

    Science.gov (United States)

    Diniz-Silva, Helena Taina; Cirino, Isis Caroline da Silva; Falcão-Silva, Vivyanne Dos Santos; Magnani, Marciane; de Souza, Evandro Leite; Siqueira-Júnior, José P

    2016-01-01

    Tannins have shown inhibitory effects against pathogenic bacteria, and these properties make tannins potential modifying agents in bacterial resistance. The minimum inhibitory concentration (MIC) of tannic acid (TA), gallic acid (GA) and norfloxacin (Nor) against Staphylococcus aureus SA-1119 (NorA-effluxing strain) was determined using broth microdilution tests. To assess the modulation of antibiotic resistance, the MIC of Nor was determined in growth media with or without TA or GA at a subinhibitory concentration (1/4 MIC). The checkerboard method was performed to obtain the fractional inhibitory concentration index (FICI) for the combined application of TA and Nor. TA displayed a weak inhibitory effect (MIC 512 μg/ml) against S. aureus SA-1119, while no inhibitory effect was displayed by GA (MIC >512 μg/ml). However, when TA was tested at a subinhibitory concentration in combination with Nor, the MIC of Nor against S. aureus SA-1119 decreased from 128 to 4 μg/ml (32-fold); this effect was not observed for GA. In the checkerboard assay, the MIC of TA and Nor decreased from 512 to 128 μg/ml (4-fold) and from 128 to 8 μg/ml (16-fold), respectively. The combination of TA and Nor presented an FICI as low as 0.31, which indicates a synergistic interaction. TA is a potential agent for increasing the clinical efficacy of Nor to control resistant S. aureus. © 2016 S. Karger AG, Basel.

  18. Adsorption Characteristics of Norfloxacin by Biochar Prepared by Cassava Dreg: Kinetics, Isotherms, and Thermodynamic Analysis

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    Dan Feng

    2015-08-01

    Full Text Available Biochars (BC generated from biomass residues have been recognized as effective sorbents for organic compounds. In this study, biochars as adsorbents for the removal of norfloxacin (NOR from aqueous solutions were evaluated. Biochars were prepared from cassava dregs at 350 °C, 450 °C, 550 °C, 650 °C, and 750 °C, respectively (labeled as BC350, BC450, BC550, BC650, and BC750. The results showed that the kinetic data were best fitted to the pseudo second-order model, indicating that the sorption was governed by the availability of sorption sites on the biochar surfaces rather than the NOR concentration in the solution. Sorption isotherms of NOR were well described by the Freundlich model, and the Freundlich coefficients (lgkF increased with the pyrolysis temperature of biochars. Thermodynamic analysis indicated the feasibility and spontaneity of the NOR adsorption process. The NOR adsorption on BC450, BC550, BC650, and BC750 was an endothermic process, while an exothermic process occurred for BC350. FTIR studies further suggested that the adsorption mechanism was possibly attributable to H-bond and π-π interactions between NOR and biochars. Overall, this work constitutes a basis for further research considering the bioavailability and toxicity of antibiotics in the presence of biochar.

  19. A novel biochar derived from cauliflower (Brassica oleracea L.) roots could remove norfloxacin and chlortetracycline efficiently.

    Science.gov (United States)

    Qin, Tingting; Wang, Zhaowei; Xie, Xiaoyun; Xie, Chaoran; Zhu, Junmin; Li, Yan

    2017-12-01

    The biochar was prepared by pyrolyzing the roots of cauliflowers, at a temperature of 500 °C under oxygen-limited conditions. The structure and characteristics of the biochar were examined using scanning electron microscopy, an energy dispersive spectrometer, a zeta potential analyzer, and Fourier transform infrared spectroscopy. The effects of the temperature, the initial pH, antibiotic concentration, and contact time on the adsorption of norfloxacin (NOR) and chlortetracycline (CTC) onto the biochar were investigated. The adsorption kinetics of NOR and CTC onto the biochar followed the pseudo-second-order kinetic and intra-particle diffusion models. The adsorption isotherm experimental data were well fitted to the Langmuir and Freundlich isotherm models. The maximum adsorption capacities of NOR and CTC were 31.15 and 81.30 mg/g, respectively. There was little difference between the effects of initial solution pH (4.0-10.0) on the adsorption of NOR or CTC onto the biochar because of the buffering effect. The biochar could remove NOR and CTC efficiently in aqueous solutions because of its large specific surface area, abundant surface functional groups, and particular porous structure. Therefore, it could be used as an excellent adsorbent material because of its low cost and high efficiency and the extensive availability of the raw materials.

  20. Potentiating antibiotics in drug-resistant clinical isolates via stimuli-activated superoxide generation.

    Science.gov (United States)

    Courtney, Colleen M; Goodman, Samuel M; Nagy, Toni A; Levy, Max; Bhusal, Pallavi; Madinger, Nancy E; Detweiler, Corrella S; Nagpal, Prashant; Chatterjee, Anushree

    2017-10-01

    The rise of multidrug-resistant (MDR) bacteria is a growing concern to global health and is exacerbated by the lack of new antibiotics. To treat already pervasive MDR infections, new classes of antibiotics or antibiotic adjuvants are needed. Reactive oxygen species (ROS) have been shown to play a role during antibacterial action; however, it is not yet understood whether ROS contribute directly to or are an outcome of bacterial lethality caused by antibiotics. We show that a light-activated nanoparticle, designed to produce tunable flux of specific ROS, superoxide, potentiates the activity of antibiotics in clinical MDR isolates of Escherichia coli , Salmonella enterica , and Klebsiella pneumoniae . Despite the high degree of antibiotic resistance in these isolates, we observed a synergistic interaction between both bactericidal and bacteriostatic antibiotics with varied mechanisms of action and our superoxide-producing nanoparticles in more than 75% of combinations. As a result of this potentiation, the effective antibiotic concentration of the clinical isolates was reduced up to 1000-fold below their respective sensitive/resistant breakpoint. Further, superoxide-generating nanoparticles in combination with ciprofloxacin reduced bacterial load in epithelial cells infected with S. enterica serovar Typhimurium and increased Caenorhabditis elegans survival upon infection with S. enterica serovar Enteriditis, compared to antibiotic alone. This demonstration highlights the ability to engineer superoxide generation to potentiate antibiotic activity and combat highly drug-resistant bacterial pathogens.

  1. Molecular Identification of Streptomyces producing antibiotics and their antimicrobial activities

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    Latifa A. Al_husnan

    2016-12-01

    Full Text Available Five strains of Streptomyces, namely S, N, W, E and C (designations should be mentioned in detail here isolated from the rhizosphere soil cultivated with palm Alajua (date, pressed dates, AlMedina city, Saudi Arabia, were induced to produce antibiotics. Antimicrobial activities were determined on solid medium supplemented with starch. The detection was based on the formation of transparent zones around colonies. The results indicated that isolates had antibacterial activities against Staphylococcus aureus, Bacillus cereus, B. subtilis, Pseudomonas aeruginosa and also showed antifungal activity against Candida albicans and Aspergillus niger. DNA extracted from five isolates was used as template for 16s rDNA gene amplification. The expected PCR size was 1.5 kbp;1.6 kbp; 1.25 kbp; 1.25kbp and 1.0 k bp for S, N, W, E and C isolates respectively using universal 16s rDNA gene primers using direct PCR. The isolates varied morphologically on the basis of spore color, aerial and substrate mycelium formation, and production of diffusible pigment. Isolates were tested under a microscope by using slide culture technique. The results indicate that the soil of this region is source of Streptomyces having antibacterial and antifungal activity and thus better utilization of these microorganisms as biological control agents.

  2. Impact of anthropogenic activities on the dissemination of antibiotic resistance across ecological boundaries.

    Science.gov (United States)

    Tripathi, Vijay; Cytryn, Eddie

    2017-02-28

    Antibiotics are considered to be one of the major medical breakthroughs in history. Nonetheless, over the past four decades, antibiotic resistance has reached alarming levels worldwide and this trend is expected to continue to increase, leading some experts to forecast the coming of a 'post-antibiotic' era. Although antibiotic resistance in pathogens is traditionally linked to clinical environments, there is a rising concern that the global propagation of antibiotic resistance is also associated with environmental reservoirs that are linked to anthropogenic activities such as animal husbandry, agronomic practices and wastewater treatment. It is hypothesized that the emergence and dissemination of antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) within and between environmental microbial communities can ultimately contribute to the acquisition of antibiotic resistance in human pathogens. Nonetheless, the scope of this phenomenon is not clear due to the complexity of microbial communities in the environment and methodological constraints that limit comprehensive in situ evaluation of microbial genomes. This review summarizes the current state of knowledge regarding antibiotic resistance in non-clinical environments, specifically focusing on the dissemination of antibiotic resistance across ecological boundaries and the contribution of this phenomenon to global antibiotic resistance. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  3. A New Twist to the Kirby-Bauer Antibiotic Susceptibility Test Activity?Increasing Antibiotic Sensitivity of Pseudomonas fluorescens through Thermal Stress

    OpenAIRE

    Gerbig, Donald G.; Engohang-Ndong, Jean; Aubihl, Heather

    2013-01-01

    Antibiotic sensitivity and the effect of temperature on microbial growth are two standard laboratory activities found in most microbial laboratory manuals. We have found a novel way to combine the two activities to demonstrate how temperature can influence antibiotic sensitivity using a standard incubator in instructional laboratory settings. This activity reinforces the important concepts of microbial growth and temperature along with Kirby-Bauer antibiotic susceptibility testing. We found t...

  4. Sweet antibiotics – the role of glycosidic residues in antibiotic and antitumor activity and their randomization

    Czech Academy of Sciences Publication Activity Database

    Křen, Vladimír; Řezanka, Tomáš

    2008-01-01

    Roč. 32, č. 5 (2008), s. 858-889 ISSN 0168-6445 R&D Projects: GA MŠk(CZ) LC06010; GA AV ČR IAA400200503 Institutional research plan: CEZ:AV0Z50200510 Keywords : glycosides * sweet antibiotics * aglycone Subject RIV: CE - Biochemistry Impact factor: 7.963, year: 2008

  5. Enzyme activities and antibiotic susceptibility of colonial variants of Bacillus subtilis and Bacillus licheniformis.

    OpenAIRE

    Carlisle, G E; Falkinham, J O

    1989-01-01

    A nonmucoid colonial variant of a mucoid Bacillus subtilis strain produced less amylase activity and a transparent colonial variant of a B. licheniformis strain produced less protease activity compared with their parents. Antibiotic susceptibility patterns of the colonial variants differed, and increased resistance to beta-lactam antibiotics was correlated with increased production of extracellular beta-lactamase.

  6. Antibiotic-modifying activity of riachin, a non-cyanogenic cyanoglycoside extracted from Bauhinia pentandra.

    Science.gov (United States)

    de Farias, Pablo Antonio Maia; Figueredo, Fernando Gomes; Lucas, Aline Maria Brito; de Moura, Rafael Barbosa; Coutinho, Henrique Douglas Melo; da Silva, Tania Maria Sarmento; Martin, Ana Luiza de Aguiar Rocha; Fonteles, Marta Maria de França

    2015-01-01

    The search for new active compounds from the Brazilian flora has intensified in recent years, especially for new drugs with antibiotic potential. Accordingly, the aim of this study was to determine whether riachin has antibiotic activity in itself or is able to modulate the activity of conventional antibiotics. A non-cyanogenic cyanoglycoside known as riachin was isolated from Bauhinia pentandra, and was tested alone and in combination with three antibiotics (clindamycin, amikacin, and gentamicin) against multiresistant bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). Riachin did not show significant antibiotic activity when tested alone against any strain (P>0.05). However, when combined with conventional antibiotics, it showed drug-modifying activity against strains of S. aureus exposed to clindamycin (P<0.001) as well as against P. aeruginosa exposed to amikacin (P<0.001). Although riachin did not show direct antibiotic activity, it had synergistic activity when combined with amikacin or clindamycin. The mechanism of action of this synergism is under investigation. The results of this work demonstrate that some substances of natural origin can enhance the effectiveness of certain antibiotics, which means a substantial reduction in the drug dose required and possibly in consequent adverse events for patients.

  7. Adsorption and degradation of five selected antibiotics in agricultural soil.

    Science.gov (United States)

    Pan, Min; Chu, L M

    2016-03-01

    Large quantities of antibiotics are being added to agricultural fields worldwide through the application of wastewater, manures and biosolids, resulting in antibiotic contamination and elevated environmental risks in terrestrial environments. Most studies on the environmental fate of antibiotics focus on aquatic environments or wastewater treatment plants. Little is known about the behavior of antibiotics at environmentally relevant concentrations in agricultural soil. In this study we evaluated the adsorption and degradation of five different antibiotics (tetracycline, sulfamethazine, norfloxacin, erythromycin, and chloramphenicol) in sterilized and non-sterilized agricultural soils under aerobic and anaerobic conditions. Adsorption was highest for tetracycline (Kd, 1093 L/kg), while that for sulfamethazine was negligible (Kd, 1.365 L/kg). All five antibiotics were susceptible to microbial degradation under aerobic conditions, with half-lives ranging from 2.9 to 43.3 d in non-sterilized soil and 40.8 to 86.6 d in sterilized soil. Degradation occurred at a higher rate under aerobic conditions but was relatively persistent under anaerobic conditions. For all the antibiotics, a higher initial concentration was found to slow down degradation and prolong persistence in soil. The degradation behavior of the antibiotics varied in relation to their physicochemical properties as well as the microbial activities and aeration of the recipient soil. The poor adsorption and relative persistence of sulfamethazine under both aerobic and anaerobic conditions suggest that it may pose a higher risk to groundwater quality. An equation was proposed to predict the fate of antibiotics in soil under different field conditions, and assess their risks to the environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Post treatment of antibiotic wastewater by adsorption on activated carbon

    Science.gov (United States)

    Mullai, P.; Rajesh, V.

    2018-02-01

    The most common method of treating industrial wastewater involves biomethanation in anaerobic digesters. This biological treatment process is ineffective in color removal and it requires post-treatment methods. The color is the first contaminant in wastewater which affects the water bodies in several ways. As the anaerobically digested antibiotic wastewater was found with color, an attempt was made to remove color using granulated activated carbon as an adsorbent. Experiments were carried out in batch reactors to find out the color removal efficiency of the wastewater at four different dosages such as 25, 50, 75 and 100 mg of adsorbent material at each of the four different initial concentrations of effluent like 1956, 1450, 1251 and 1040 mg COD/L. The steady state values of color removal efficiencies were 96.6, 97.64, 98.64 and 99.63%, respectively, using 100 mg of activated carbon under shaking condition at the end of the 120th min. The effect of contact time on the percentage of color removal was also studied. It was observed that the adsorption of effluent obtained equilibrium at 120 minutes. The equilibrium data fitted well with the Langmuir and Freundlich isotherms.

  9. In vitro antimalarial activity of novel semisynthetic nocathiacin I antibiotics.

    Science.gov (United States)

    Sharma, Indu; Sullivan, Margery; McCutchan, Thomas F

    2015-01-01

    Presently, the arsenal of antimalarial drugs is limited and needs to be replenished. We evaluated the potential antimalarial activity of two water-soluble derivatives of nocathiacin (BMS461996 and BMS411886) against the asexual blood stages of Plasmodium falciparum. Nocathiacins are a thiazolyl peptide group of antibiotics, are structurally related to thiostrepton, have potent activity against a wide spectrum of multidrug-resistant Gram-positive bacteria, and inhibit protein synthesis. The in vitro growth inhibition assay was done using three laboratory strains of P. falciparum displaying various levels of chloroquine (CQ) susceptibility. Our results indicate that BMS461996 has potent antimalarial activity and inhibits parasite growth with mean 50% inhibitory concentrations (IC50s) of 51.55 nM for P. falciparum 3D7 (CQ susceptible), 85.67 nM for P. falciparum Dd2 (accelerated resistance to multiple drugs [ARMD]), and 99.44 nM for P. falciparum K1 (resistant to CQ, pyrimethamine, and sulfadoxine). Similar results at approximately 7-fold higher IC50s were obtained with BMS411886 than with BMS461996. We also tested the effect of BMS491996 on gametocytes; our results show that at a 20-fold excess of the mean IC50, gametocytes were deformed with a pyknotic nucleus and growth of stage I to IV gametocytes was arrested. This preliminary study shows a significant potential for nocathiacin analogues to be developed as antimalarial drug candidates and to warrant further investigation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  10. A new antibiotic with potent activity targets MscL.

    Science.gov (United States)

    Iscla, Irene; Wray, Robin; Blount, Paul; Larkins-Ford, Jonah; Conery, Annie L; Ausubel, Frederick M; Ramu, Soumya; Kavanagh, Angela; Huang, Johnny X; Blaskovich, Mark A; Cooper, Matthew A; Obregon-Henao, Andres; Orme, Ian; Tjandra, Edwin S; Stroeher, Uwe H; Brown, Melissa H; Macardle, Cindy; van Holst, Nick; Ling Tong, Chee; Slattery, Ashley D; Gibson, Christopher T; Raston, Colin L; Boulos, Ramiz A

    2015-07-01

    The growing problem of antibiotic-resistant bacteria is a major threat to human health. Paradoxically, new antibiotic discovery is declining, with most of the recently approved antibiotics corresponding to new uses for old antibiotics or structurally similar derivatives of known antibiotics. We used an in silico approach to design a new class of nontoxic antimicrobials for the bacteria-specific mechanosensitive ion channel of large conductance, MscL. One antimicrobial of this class, compound 10, is effective against methicillin-resistant Staphylococcus aureus with no cytotoxicity in human cell lines at the therapeutic concentrations. As predicted from in silico modeling, we show that the mechanism of action of compound 10 is at least partly dependent on interactions with MscL. Moreover we show that compound 10 cured a methicillin-resistant S. aureus infection in the model nematode Caenorhabditis elegans. Our work shows that compound 10, and other drugs that target MscL, are potentially important therapeutics against antibiotic-resistant bacterial infections.

  11. Elucidating Direct Photolysis Mechanisms of Different Dissociation Species of Norfloxacin in Water and Mg2+ Effects by Quantum Chemical Calculations.

    Science.gov (United States)

    Wang, Se; Wang, Zhuang

    2017-11-11

    The study of pollution due to combined antibiotics and metals is urgently needed. Photochemical processes are an important transformation pathway for antibiotics in the environment. The mechanisms underlying the effects of metal-ion complexation on the aquatic photochemical transformation of antibiotics in different dissociation forms are crucial problems in science, and beg solutions. Herein, we investigated the mechanisms of direct photolysis of norfloxacin (NOR) in different dissociation forms in water and metal ion Mg 2+ effects using quantum chemical calculations. Results show that different dissociation forms of NOR had different maximum electronic absorbance wavelengths (NOR 2+ direct photolysis pathways were de-ethylation (N7-C8 bond cleavage) and decarboxylation (C2-C5 bond cleavage). Furthermore, the presence of Mg 2+ changed the order of the wavelength at maximum electronic absorbance (NOR⁺-Mg 2+ direct photolysis of NOR⁰, NOR⁺, and NOR 2+ . The calculated TS results indicated that the presence of Mg 2+ increased E a for most direct photolysis pathways of NOR, while it decreased E a for some direct photolysis pathways such as the loss of the piperazine ring and the damage of the piperazine ring of NOR⁰ and the defluorination of NOR⁺.

  12. A simple and sensitive method for determination of Norfloxacin in pharmaceutical preparations

    Directory of Open Access Journals (Sweden)

    Zhuo Ye

    2015-06-01

    Full Text Available In this approach, a new voltammetric method for determination of norfloxacin was proposed with high sensitivity and wider detection linear range. The used voltammetric sensor was fabricated simply by coating a layer of graphene oxide (GO and Nafion composited film on glassy carbon electrode. The advantage of proposed method was sensitive electrochemical response for norfloxacin, which was attributed to the excellent electrical conductivity of GO and the accumulating function of Nafion under optimum experimental conditions, the present method revealed a good linear response for determination of norfloxacin in the range of 1×10-8mol/L-7×10-6 mol/L with a detection limit of 5×10-9 mol/L. The proposed method was successfully applied in the determination of norfloxacin in capsules with satisfactory results.

  13. Follow up of acute gonococcal urethritis in males treated with norfloxacin

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    Chari KVR

    1994-01-01

    Full Text Available This subject was undertaken to confirm the efficacy of norfloxacin in acute gonorrhoea and to note the relapse if any during the follow up period of 3 months. 27 male patients suffering from acute gonorrhoea were treated with 800 mgs of norfloxacin as single oral dose. In all cases, gonococci disappeared from urethral smears by 8 hours, urethral discharge subsided by 72 hrs, urine on naked eye examination cleared in 4 days except in 1 case and burning micturition subsided by 7 days. Cure rate was 100% in the study. No relapse was found at the end of follow up of 3 months. No adverse reactions were observed to norfloxacin except headache in 2 cases. Norfloxacin was safe and effective in the treatment of acute gonorrhoea.

  14. Modification of pharmacokinetics of norfloxacin following oral administration of curcumin in rabbits

    Science.gov (United States)

    Pavithra, B. H.; Jayakumar, K.

    2009-01-01

    Investigation was carried out in adult New Zealand white rabbits to study the influence of curcumin pre-treatment on pharmacokinetic disposition of norfloxacin following single oral administration. Sixteen rabbits were divided into two groups of eight each consisting of either sex. Animals in group-I were administered norfloxacin (100 mg/kg body weight p.o), while animals in group-II received similar dose of norfloxacin after pre-treatment with curcumin (60 mg/kg body weight per day, 3 days, p.o). Blood samples were drawn from the marginal ear vein into heparin-coated vials at 0 (zero time), 5, 10, 15, 30 min and 1, 2, 4, 6, 12 and 24 h post-treatment. Plasma norfloxacin concentrations were determined by high performance liquid chromatography. The plasma concentration-time profile of norfloxacin was adequately described by a one-compartment open model. The pharmacokinetic data revealed that curcumin-treated animals had significantly (p ≤ 0.05) higher area under the plasma concentration-time curve and area under the first moment of plasma drug concentration-time curve. Prior treatment of curcumin significantly (p ≤ 0.05) increased elimination half-life and volume of distribution of norfloxacin. Further treatment with curcumin reduced loading and maintenance doses by 26% and 24% respectively. PMID:19934593

  15. The Effects of Antibiotics on Microbial Community Composition in an Estuary Reservoir during Spring and Summer Seasons

    Directory of Open Access Journals (Sweden)

    Zheng Xu

    2018-02-01

    Full Text Available The increased antibiotic pollutants in aquatic environments pose severe threats on microbial ecology due to their extensive distribution and antibacterial properties. A total of 16 antibiotics including fluoroquinolones (FQs (ofloxacin (OFX, ciprofloxacin (CFX, norfloxacin (NFX, Sulfonamides (SAs (sulfamonomethoxine (SMM, sulfadiazine (SDZ, sulfaquinoxaline (SQX, Tetracyclines (TCs (tetracycline (TC, doxycycline (DC, β-lactams (penicillin G (PEN G, penicillin V (PEN V, cefalexin (LEX, Macrolides (MLs (erythromycin-H2O (ETM, tylosin (TYL and other antibiotics (Polymix-B (POL, Vancomycin (VAN, Lincomycin (LIN were detected in the surface water of the Qingcaosha Reservoir. Multivariate statistical analysis indicated that both water quality and physicochemical indexes have less contributions on variations of these antibiotics, suggesting the concentrations of antibiotics inside the reservoir are mainly affected by upstream runoff and anthropic activity along the river. Antibiotics including TYL, PEN G and ETM showed significant correlations with variations of bacterial community composition, and closely connected with various gram-negative bacteria in co-occurrence/exclusion patterns of the network, suggesting these bacterial taxa play important roles in the course of migration and transformation of related antibiotics. In conclusion, further research is required to evaluate the potential risk of genetic transfer of resistance to related bacteria induced by long-term exposure to low levels of antibiotics in the environment.

  16. Activation of Antibiotic Production in Bacillus spp. by Cumulative Drug Resistance Mutations.

    Science.gov (United States)

    Tojo, Shigeo; Tanaka, Yukinori; Ochi, Kozo

    2015-12-01

    Bacillus subtilis strains produce a wide range of antibiotics, including ribosomal and nonribosomal peptide antibiotics, as well as bacilysocin and neotrehalosadiamine. Mutations in B. subtilis strain 168 that conferred resistance to drugs such as streptomycin and rifampin resulted in overproduction of the dipeptide antibiotic bacilysin. Cumulative drug resistance mutations, such as mutations in the mthA and rpsL genes, which confer low- and high-level resistance, respectively, to streptomycin, and mutations in rpoB, which confer resistance to rifampin, resulted in cells that overproduced bacilysin. Transcriptional analysis demonstrated that the enhanced transcription of biosynthesis genes was responsible for the overproduction of bacilysin. This approach was effective also in activating the cryptic genes of Bacillus amyloliquefaciens, leading to actual production of antibiotic(s). Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Carbohydrate-Based Host-Guest Complexation of Hydrophobic Antibiotics for the Enhancement of Antibacterial Activity.

    Science.gov (United States)

    Jeong, Daham; Joo, Sang-Woo; Shinde, Vijay Vilas; Cho, Eunae; Jung, Seunho

    2017-08-08

    Host-guest complexation with various hydrophobic drugs has been used to enhance the solubility, permeability, and stability of guest drugs. Physical changes in hydrophobic drugs by complexation have been related to corresponding increases in the bioavailability of these drugs. Carbohydrates, including various derivatives of cyclodextrins, cyclosophoraoses, and some linear oligosaccharides, are generally used as host complexation agents in drug delivery systems. Many antibiotics with low bioavailability have some limitations to their clinical use due to their intrinsically poor aqueous solubility. Bioavailability enhancement is therefore an important step to achieve the desired concentration of antibiotics in the treatment of bacterial infections. Antibiotics encapsulated in a complexation-based drug delivery system will display improved antibacterial activity making it possible to reduce dosages and overcome the serious global problem of antibiotic resistance. Here, we review the present research trends in carbohydrate-based host-guest complexation of various hydrophobic antibiotics as an efficient delivery system to improve solubility, permeability, stability, and controlled release.

  18. Redox-Active Antibiotics Control Gene Expression and Community Behavior in Divergent Bacteria

    OpenAIRE

    Dietrich, Lars E. P.; Teal, Tracy K.; Price-Whelan, Alexa; Newman, Dianne K.

    2008-01-01

    It is thought that bacteria excrete redox-active pigments as antibiotics to inhibit competitors. In Pseudomonas aeruginosa, the endogenous antibiotic pyocyanin activates SoxR, a transcription factor conserved in Proteo- and Actinobacteria. In Escherichia coli, SoxR regulates the superoxide stress response. Bioinformatic analysis coupled with gene expression studies in P. aeruginosa and Streptomyces coelicolor revealed that the majority of SoxR regulons in bacteria lack the genes required for ...

  19. Synergistic antimicrobial activity between pentacyclic triterpenoids and antibiotics against Staphylococcus aureus strains

    Directory of Open Access Journals (Sweden)

    Navaratnam Parasakthi

    2011-06-01

    Full Text Available Abstract Background There has been considerable effort to discover plant-derived antibacterials against methicillin-resistant strains of Staphylococcus aureus (MRSA which have developed resistance to most existing antibiotics, including the last line of defence, vancomycin. Pentacyclic triterpenoid, a biologically diverse plant-derived natural product, has been reported to show anti-staphylococcal activities. The objective of this study is to evaluate the interaction between three pentacyclic triterpenoid and standard antibiotics (methicillin and vancomycin against reference strains of Staphylococcus aureus. Methods and Results The activity of the standard antibiotics and compounds on reference methicillin-sensitive and resistant strains of S. aureus were determined using the macrodilution broth method. The minimum inhibitory concentration (MIC of the compounds was compared with that of the standard antibiotics. The interaction between any two antimicrobial agents was estimated by calculating the fractional inhibitory concentration (FIC index of the combination. The various combinations of antibiotics and compounds reduced the MIC to a range of 0.05 to 50%. Conclusion Pentacyclic triterpenoids have shown anti-staphylococcal activities and although individually weaker than common antibiotics produced from bacteria and fungi, synergistically these compounds may use different mechanism of action or pathways to exert their antimicrobial effects, as implicated in the lowered MICs. Therefore, the use of current antibiotics could be maintained in their combination with plant-derived antibacterial agents as a therapeutic option in the treatment of S. aureus infections.

  20. Synergy between antibiotics and natural agents results in increased antimicrobial activity against Staphylococcus epidermidis.

    Science.gov (United States)

    Abidi, Syed Hani; Ahmed, Khalid; Sherwani, Sikander Khan; Kazmi, Shahana Urooj

    2015-09-27

    Staphylococcus epidermidis is one of the most frequent causes of biofilm-associated infections on indwelling medical devices. With the emergence of methicillin-resistant S. epidermidis (MRSE), there is an urgent need to discover novel active agents against a range of Gram-positive pathogens. We screened the clinical isolates of S. epidermidis for susceptibility/resistance against commonly prescribed antibiotics. Furthermore, we tested some natural agents alone and in combination with antibiotics to find possible synergistic antimicrobial effects. S. epidermidis clinical isolates were screened for susceptibility/resistance against vancomycin, erythromycin, tetracycline, chloramphenicol, ampicillin, ofloxacin, cephalexin, and gentamicin using the Kirby-Bauer disk diffusion method. The antimicrobial potential of Camellia sinensis, Juglans regia, and Hippophae rhamnoides alone and in combination with antibiotics were examined using the disk diffusion method, where the antimicrobial potential activity was measured in terms of formation of zones of inhibition. Most S. epidermidis isolates were found to be resistant to one or more antibiotics. Gentamycin and ofloxacin were found to be the most effective antibiotics against S. epidermidis isolates. Extracts of Hippophae rhamnoides, Juglans regia, and Camellia sinensis were found to be equally effective against S. epidermidis isolates. In combination with antibiotics, these extracts exhibited appreciable synergistic activity; the highest synergistic activity was observed with erythromycin and cephalexin. In the case of cephalexin, a reversion in resistance was observed. The plant extracts used in the study exhibited additive and synergistic antibacterial activity against S. epidermidis, hence providing an effective alternative to deal with the problem of multidrug resistance.

  1. Distribution and elimination of Norfloxacin in Fenneropenaeus chinensis larvae

    Science.gov (United States)

    Sun, Ming; Li, Jian; Zhao, Fazhen; Li, Jitao; Chang, Zhiqiang

    2013-09-01

    This study examined the distribution and elimination of Norfloxacin (NFLX) in Fenneropenaeus chinensis ovary and egg and newly hatched larvae. Mature parental shrimp were exposed to 4 or 10 mg L-1 NFLX for 2 or 5 d. Ovary and eggs of the shrimp were sampled after spawning in order to detect NFLX residue using high-performance liquid chromatography (HPLC). Results showed that NFLX residue accumulated in F. chinensis eggs after the parental exposure, with the highest residue detected in ovary. To examine the fate of NFLX residue in larvae, we further determined the concentration of NFLX residue in F. chinensis eggs and larvae at 4 different developmental stages after 24-h exposure. From the newly metamorphosed larvae (0 h post-metamorphosis, h.p.m), samples were taken at different time intervals to 72 h.p.m. HPLC assay showed that the concentrations of NFLX residue in zoea exposed to 4 and 10 mg L-1 NFLX were the highest at 1.5 h, i.e., 0.332 and 0.454 μg g-1, respectively. At the two NFLX exposure levels, the elimination time of half NFLX (half life) in nauplius was 45.36 and 49.85 h, respectively, followed by that in zoea (31.68 and 33.13 h), mysis larvae (42.24 and 47.28 h) and postlarvae (24.48 and 30.96 h). Both NFLX exposure levels had a germicidal effect. The distribution and elimination of NFLX residue in F. chinensis tissue, eggs and larvae correlated well with the drug exposure level. The disappearance of NFLX residue coincided with the larval growth, and the half-life of NFLX decreased with the larval development.

  2. The role of active efflux in antibiotic - resistance of clinical isolates of Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Falsafi T

    2009-01-01

    Full Text Available Purpose: In gram-negative bacteria, active efflux pumps that excrete drugs can confer resistance to antibiotics however, in Helicobacter pylori this role is not well established. The purpose of this study is to evaluate the role of active efflux in resistance of H. pylori isolates to antibiotics. Materials and Methods: Twelve multiple antibiotic resistant (MAR isolates resistant to at least four antibiotics, including β-lactams, metronidazole, tetracycline, erythromycin, and ciprofloxacin; three resistant to only β-lactams, and two hyper-susceptible isolates, were obtained from screening of 96 clinical isolates of H. pylori . Their minimal inhibitory concentrations (MICs for antibiotics and ethidium-bromide (EtBr were compared in the presence- and absence of a proton-conductor, carbonyl cyanide-m chlorophenyl-hydrazone (CCCP using agar-dilution and disc diffusion. Drug accumulation studies for EtBr and antibiotics were assessed in the presence and absence of CCCP using spectrofluorometry. Results: MIC of EtBr for eight MAR-isolates was decreased two- to four-folds in the presence of CCCP, of which five showed reduced MICs for β-lactam, metronidazole, tetracycline, and ciprofloxacin with CCCP. Accumulation of EtBr by the MAR-isolates was rapid and not dependant on the pattern of multiple resistance. Antibiotic accumulation assay confirmed the presence of energy-dependant efflux of β-lactam, metronidazole, tetracycline, and ciprofloxacin, but no erythromycin in five MAR isolates. Energy-dependant efflux of EtBr or antibiotics was not observed for four MAR-isolates, and three isolates were resistant only to β-lactams. Conclusion: Energy-dependant efflux plays a role in the resistance of H. pylori clinical isolates to structurally unrelated antibiotics in a broadly specific multidrug efflux manner. Difference in the efflux potential of MAR isolates may be related to the presence or absence of functional efflux-pumps in diverse H. pylori

  3. Occurrence and distribution of antibiotics in coastal water of the Bohai Bay, China: Impacts of river discharge and aquaculture activities

    International Nuclear Information System (INIS)

    Zou Shichun; Xu Weihai; Zhang Ruijie; Tang Jianhui; Chen Yingjun; Zhang Gan

    2011-01-01

    The presence of 21 antibiotics in six different groups was investigated in coastal water of the Bohai Bay. Meantime, to illuminate the potential effects caused by the river discharge and aquaculture activities, wastewater from three breeding plants and surface water from six rivers flowing into the Bohai Bay were also analyzed for the selected antibiotics. The result revealed that measured antibiotics in the North Bobai Bay were generally higher than those in the South, highlighting the remarkable effects of high density of human activities on the exposure of antibiotics in environment. The antibiotics found in the six rivers were generally higher than those in the Bohai Bay reflecting the important antibiotics source of river discharge. This study reveals that the high consumption of some antibiotics in aquaculture activities may pose high ecological risk to the bay. - Highlights: → Some antibiotics were ubiquitous with high concentration in the Bohai bay, North China. → The antibiotics were mainly from the six rivers discharge around the Bay. → Antibiotics are commonly used in aquaculture activities around the Bay. → Aquaculture was suggested to be an important antibiotics source in the Bay. - River discharge and aquaculture were suggested to be important sources for antibiotics occurred in the coastal water of the Bohai Bay, North China.

  4. A Simple Assay to Screen Antimicrobial Compounds Potentiating the Activity of Current Antibiotics

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    Junaid Iqbal

    2013-01-01

    Full Text Available Antibiotic resistance continues to pose a significant problem in the management of bacterial infections, despite advances in antimicrobial chemotherapy and supportive care. Here, we suggest a simple, inexpensive, and easy-to-perform assay to screen antimicrobial compounds from natural products or synthetic chemical libraries for their potential to work in tandem with the available antibiotics against multiple drug-resistant bacteria. The aqueous extract of Juglans regia tree bark was tested against representative multiple drug-resistant bacteria in the aforementioned assay to determine whether it potentiates the activity of selected antibiotics. The aqueous extract of J. regia bark was added to Mueller-Hinton agar, followed by a lawn of multiple drug-resistant bacteria, Salmonella typhi or enteropathogenic E. coli. Next, filter paper discs impregnated with different classes of antibiotics were placed on the agar surface. Bacteria incubated with extract or antibiotics alone were used as controls. The results showed a significant increase (>30% in the zone of inhibition around the aztreonam, cefuroxime, and ampicillin discs compared with bacteria incubated with the antibiotics/extract alone. In conclusion, our assay is able to detect either synergistic or additive action of J. regia extract against multiple drug-resistant bacteria when tested with a range of antibiotics.

  5. Does human activity impact the natural antibiotic resistance background? Abundance of antibiotic resistance genes in 21 Swiss lakes.

    Science.gov (United States)

    Czekalski, Nadine; Sigdel, Radhika; Birtel, Julia; Matthews, Blake; Bürgmann, Helmut

    2015-08-01

    Antibiotic resistance genes (ARGs) are emerging environmental contaminants, known to be continuously discharged into the aquatic environment via human and animal waste. Freshwater aquatic environments represent potential reservoirs for ARG and potentially allow sewage-derived ARG to persist and spread in the environment. This may create increased opportunities for an eventual contact with, and gene transfer to, human and animal pathogens via the food chain or drinking water. However, assessment of this risk requires a better understanding of the level and variability of the natural resistance background and the extent of the human impact. We have analyzed water samples from 21 Swiss lakes, taken at sampling points that were not under the direct influence of local contamination sources and analyzed the relative abundance of ARG using quantitative real-time PCR. Copy numbers of genes mediating resistance to three different broad-spectrum antibiotic classes (sulfonamides: sul1, sul2, tetracyclines: tet(B), tet(M), tet(W) and fluoroquinolones: qnrA) were normalized to copy numbers of bacterial 16S rRNA genes. We used multiple linear regression to assess if ARG abundance is related to human activities in the catchment, microbial community composition and the eutrophication status of the lakes. Sul genes were detected in all sampled lakes, whereas only four lakes contained quantifiable numbers of tet genes, and qnrA remained below detection in all lakes. Our data indicate higher abundance of sul1 in lakes with increasing number and capacity of wastewater treatment plants (WWTPs) in the catchment. sul2 abundance was rather related to long water residence times and eutrophication status. Our study demonstrates the potential of freshwater lakes to preserve antibiotic resistance genes, and provides a reference for ARG abundance from lake systems with low human impact as a baseline for assessing ARG contamination in lake water. Copyright © 2015 Elsevier Ltd. All rights

  6. In vitro and in vivo activities of antibiotic PM181104

    Digital Repository Service at National Institute of Oceanography (India)

    Mahajan, G.B.; Thomas, B.; Parab, R.; Patel, Z.E.; Kuldharan, S.; Yemparala, V.; Mishra, P.D.; Ranadive, P.; DeSouza, L.; Pari, K.; Sivaramkrishnan, H.

    assigned into 7 different treatment groups (6 mice per group) and infected intra-peritoneally with 0.1mL of MRSA strain E710 culture containing 108 -109 cfu of bacteria. PM181104 prepared in formulation was administered at 1.25, 2.5, 5 and 10mg/kg intra-venous... and 10mg/kg intra-venous (i.v.) dose immediately post infection to 3 different groups. One group received formulation excipients (vehicle control) by i.v. route and one group received 25mg/kg standard antibiotic linezolid by intra-peritoneal (i...

  7. Manipulation of pH Shift to Enhance the Growth and Antibiotic Activity of Xenorhabdus nematophila

    Directory of Open Access Journals (Sweden)

    Yonghong Wang

    2011-01-01

    Full Text Available To evaluate the effects of pH control strategy on cell growth and the production of antibiotic (cyclo(2-Me-BABA-Gly by Xenorhabdus nematophila and enhance the antibiotic activity. The effects of uncontrolled- (different initial pH and controlled-pH (different constant pH and pH-shift operations on cell growth and antibiotic activity of X. nematophila YL00I were examined. Experiments showed that the optimal initial pH for cell growth and antibiotic production of X. nematophila YL001 occurred at 7.0. Under different constant pH, a pH level of 7.5 was found to be optimal for biomass and antibiotic activity at 23.71 g/L and 100.0 U/mL, respectively. Based on the kinetic information relating to the different constant pH effects on the fermentation of X. nematophila YL001, a two-stage pH control strategy in which pH 6.5 was maintained for the first 24 h, and then switched to 7.5 after 24 h, was established to improve biomass production and antibiotic activity. By applying this pH-shift strategy, the maximal antibiotic activity and productivity were significantly improved and reaching 185.0 U/mL and 4.41 U/mL/h, respectively, compared to values obtained from constant pH operation (100.0 U/mL and 1.39 U/mL/h.

  8. Occurrence and distribution of antibiotics in coastal water of the Bohai Bay, China: impacts of river discharge and aquaculture activities.

    Science.gov (United States)

    Zou, Shichun; Xu, Weihai; Zhang, Ruijie; Tang, Jianhui; Chen, Yingjun; Zhang, Gan

    2011-10-01

    The presence of 21 antibiotics in six different groups was investigated in coastal water of the Bohai Bay. Meantime, to illuminate the potential effects caused by the river discharge and aquaculture activities, wastewater from three breeding plants and surface water from six rivers flowing into the Bohai Bay were also analyzed for the selected antibiotics. The result revealed that measured antibiotics in the North Bobai Bay were generally higher than those in the South, highlighting the remarkable effects of high density of human activities on the exposure of antibiotics in environment. The antibiotics found in the six rivers were generally higher than those in the Bohai Bay reflecting the important antibiotics source of river discharge. This study reveals that the high consumption of some antibiotics in aquaculture activities may pose high ecological risk to the bay. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Menadione (vitamin K enhances the antibiotic activity of drugs by cell membrane permeabilization mechanism

    Directory of Open Access Journals (Sweden)

    Jacqueline C. Andrade

    2017-01-01

    Full Text Available Menadione, vitamin K3, belongs to the class of lipid-soluble vitamins and lipophilic substances as menadione cause disturbances in the bacterial membrane, resulting in damage to the fundamental elements for the integrity of the membrane, thus allowing increased permeability. Accordingly, the aim of this study was to evaluate in vitro the antibiotic-modifying activity of menadione in multiresistant strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, with a gradual increase in its subinhibitory concentration. In addition, menadione was compared with cholesterol and ergosterol for similarity in mechanism of drug modulatory action. Antibiotic-modifying activity and antibacterial effect were determined by the broth microdilution assay. Menadione, cholesterol and ergosterol showed modulatory activity at clinically relevant concentrations, characterizing them as modifiers of bacterial drug resistance, since they lowered the MIC of the antibiotics tested. This is the first report of the antibacterial activity of menadione and its potentiation of aminoglycosides against multiresistant bacteria.

  10. Presence and biological activity of antibiotics used in fuel ethanol and corn co-product production.

    Science.gov (United States)

    Compart, D M Paulus; Carlson, A M; Crawford, G I; Fink, R C; Diez-Gonzalez, F; Dicostanzo, A; Shurson, G C

    2013-05-01

    Antibiotics are used in ethanol production to control bacteria from competing with yeast for nutrients during starch fermentation. However, there is no published scientific information on whether antibiotic residues are present in distillers grains (DG), co-products from ethanol production, or whether they retain their biological activity. Therefore, the objectives of this study were to quantify concentrations of various antibiotic residues in DG and determine whether residues were biologically active. Twenty distillers wet grains and 20 distillers dried grains samples were collected quarterly from 9 states and 43 ethanol plants in the United States. Samples were analyzed for DM, CP, NDF, crude fat, S, P, and pH to describe the nutritional characteristics of the samples evaluated. Samples were also analyzed for the presence of erythromycin, penicillin G, tetracycline, tylosin, and virginiamycin M1, using liquid chromatography and mass spectrometry. Additionally, virginiamycin residues were determined, using a U.S. Food and Drug Administration-approved bioassay method. Samples were extracted and further analyzed for biological activity by exposing the sample extracts to 10(4) to 10(7) CFU/mL concentrations of sentinel bacterial strains Escherichia coli ATCC 8739 and Listeria monocytogenes ATCC 19115. Extracts that inhibited bacterial growth were considered to have biological activity. Physiochemical characteristics varied among samples but were consistent with previous findings. Thirteen percent of all samples contained low (≤1.12 mg/kg) antibiotic concentrations. Only 1 sample extract inhibited growth of Escherichia coli at 10(4) CFU/mL, but this sample contained no detectable concentrations of antibiotic residues. No extracts inhibited Listeria monocytogenes growth. These data indicate that the likelihood of detectable concentrations of antibiotic residues in DG is low; and if detected, they are found in very low concentrations. The inhibition in only 1 DG

  11. Disinfectant and antibiotic activities: a comparative analysis in Brazilian hospital bacterial isolates

    Directory of Open Access Journals (Sweden)

    Guimarães Márcia Aparecida

    2000-01-01

    Full Text Available Nosocomial infections are an important cause of morbidity and mortality all over the world. It has been shown that appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection control. The purpose of this study was to evaluate the bactericidal activity of some disinfectants against antibiotic-susceptible and antibiotic-resistant hospital bacterial isolates. The susceptibility of 27 clinical isolates to disinfectants and antibiotics was determined by the Association of Official Analytical Chemist?s (AOAC Use-Dilution method and by the Kirby-Bauer method, respectively. All strains tested were susceptible to sodium hypochlorite, glutaraldehyde and to the association quaternary ammonium - formaldehyde - ethyl alcohol disinfectants. However, the susceptibility of strains to phenol and to one quaternary ammonium compound was variable. Among twenty-one antibiotic-multiresistant strains (methicillin-resistant staphylococci, Enterococcus spp, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens and Escherichia coli eleven (52% and eight (38% strains were resistant to the quaternary ammonium and phenol compounds, respectively. Among six isolates that demonstrated susceptibility to antibiotics (staphylococci, Enterococcus spp, P. mirabilis, E. cloacae and E. coli two strains (33% showed resistance to these disinfectants. The results demonstrated the lack of correlation between antibiotic-susceptibility and susceptibility to disinfectants in hospital strains.

  12. Systematically Altering Bacterial SOS Activity under Stress Reveals Therapeutic Strategies for Potentiating Antibiotics.

    Science.gov (United States)

    Mo, Charlie Y; Manning, Sara A; Roggiani, Manuela; Culyba, Matthew J; Samuels, Amanda N; Sniegowski, Paul D; Goulian, Mark; Kohli, Rahul M

    2016-01-01

    The bacterial SOS response is a DNA damage repair network that is strongly implicated in both survival and acquired drug resistance under antimicrobial stress. The two SOS regulators, LexA and RecA, have therefore emerged as potential targets for adjuvant therapies aimed at combating resistance, although many open questions remain. For example, it is not well understood whether SOS hyperactivation is a viable therapeutic approach or whether LexA or RecA is a better target. Furthermore, it is important to determine which antimicrobials could serve as the best treatment partners with SOS-targeting adjuvants. Here we derived Escherichia coli strains that have mutations in either lexA or recA genes in order to cover the full spectrum of possible SOS activity levels. We then systematically analyzed a wide range of antimicrobials by comparing the mean inhibitory concentrations (MICs) and induced mutation rates for each drug-strain combination. We first show that significant changes in MICs are largely confined to DNA-damaging antibiotics, with strains containing a constitutively repressed SOS response impacted to a greater extent than hyperactivated strains. Second, antibiotic-induced mutation rates were suppressed when SOS activity was reduced, and this trend was observed across a wider spectrum of antibiotics. Finally, perturbing either LexA or RecA proved to be equally viable strategies for targeting the SOS response. Our work provides support for multiple adjuvant strategies, while also suggesting that the combination of an SOS inhibitor with a DNA-damaging antibiotic could offer the best potential for lowering MICs and decreasing acquired drug resistance. IMPORTANCE Our antibiotic arsenal is becoming depleted, in part, because bacteria have the ability to rapidly adapt and acquire resistance to our best agents. The SOS pathway, a widely conserved DNA damage stress response in bacteria, is activated by many antibiotics and has been shown to play central role in

  13. Medical-grade honey enriched with antimicrobial peptides has enhanced activity against antibiotic-resistant pathogens

    NARCIS (Netherlands)

    Kwakman, P. H. S.; de Boer, L.; Ruyter-Spira, C. P.; Creemers-Molenaar, T.; Helsper, J. P. F. G.; Vandenbroucke-Grauls, C. M. J. E.; Zaat, S. A. J.; te Velde, A. A.

    2011-01-01

    Honey has potent activity against both antibiotic-sensitive and -resistant bacteria, and is an interesting agent for topical antimicrobial application to wounds. As honey is diluted by wound exudate, rapid bactericidal activity up to high dilution is a prerequisite for its successful application. We

  14. Activity of some aminoglycoside antibiotics against true fungi, Phytophthora and Pythium species.

    Science.gov (United States)

    Lee, H B; Kim, Y; Kim, J C; Choi, G J; Park, S-H; Kim, C-J; Jung, H S

    2005-01-01

    To investigate the in vitro antifungal and antioomycete activities of some aminoglycosides against true fungi and Phytophthora and Pythium species and to evaluate the potential of the antibiotics against Phytophthora late blight on plants. Antifungal and antioomycete activities of aminoglycoside antibiotics (neomycin, paromomycin, ribostamycin and streptomycin) and a paromomycin-producing strain (Streptomyces sp. AMG-P1) against Phytophthora and Pythium species and 10 common fungi were measured in potato dextrose broth (PDB) and on seedlings in pots. Paromomycin was the most active against Phytophthora and Pythium species with a minimal inhibitory concentration of 1-10 microg ml(-1) in PDB, but displayed low to moderate activities towards other common fungi at the same concentration. Paromomycin also showed potent in vivo activity against red pepper and tomato late blight diseases with 80 and 99% control value, respectively, at 100 microg ml(-1). In addition, culture broth of Streptomyces sp. AMG-P1 as a paromomycin producer exhibited high in vivo activity against late blight at 500 microg freeze-dried weight per millilitre. Among tested aminoglycoside antibiotics, paromomycin was the most active against oomycetes both in vitro and in vivo. Data from this study show that aminoglycoside antibiotics have in vitro and in vivo activities against oomycetes, suggesting that Streptomyces sp. AMG-P1 may be used as a biocontrol agent against oomycete diseases.

  15. Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

    Energy Technology Data Exchange (ETDEWEB)

    Liu Feng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Ying Guangguo, E-mail: guangguo.ying@gmail.co [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Tao Ran; Zhao Jianliang; Yang Jifeng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Zhao Lanfeng [College of Resource and Environmental Science, South China Agricultural University, Guangzhou 510642 (China)

    2009-05-15

    The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities. - Terrestrial ecotoxicological effects of antibiotics are related to their sorption and degradation behavior in soil.

  16. Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

    International Nuclear Information System (INIS)

    Liu Feng; Ying Guangguo; Tao Ran; Zhao Jianliang; Yang Jifeng; Zhao Lanfeng

    2009-01-01

    The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities. - Terrestrial ecotoxicological effects of antibiotics are related to their sorption and degradation behavior in soil.

  17. Removal of antibiotics in conventional and advanced wastewater treatment: implications for environmental discharge and wastewater recycling.

    Science.gov (United States)

    Watkinson, A J; Murby, E J; Costanzo, S D

    2007-10-01

    Removal of 28 human and veterinary antibiotics was assessed in a conventional (activated sludge) and advanced (microfiltration/reverse osmosis) wastewater treatment plant (WWTP) in Brisbane, Australia. The dominant antibiotics detected in wastewater influents were cephalexin (med. 4.6 microg L(-1), freq. 100%), ciprofloxacin (med. 3.8 microg L(-1), freq. 100%), cefaclor (med. 0.5 microg L(-1), freq. 100%), sulphamethoxazole (med. 0.36 microg L(-1), freq. 100%) and trimethoprim (med. 0.34 microg L(-1), freq. 100%). Results indicated that both treatment plants significantly reduced antibiotic concentrations with an average removal rate from the liquid phase of 92%. However, antibiotics were still detected in both effluents from the low-to-mid ng L(-1) range. Antibiotics detected in effluent from the activated sludge WWTP included ciprofloxacin (med. 0.6 microg L(-1), freq. 100%), sulphamethoxazole (med. 0.27 microg L(-1), freq. 100%) lincomycin (med. 0.05 microg L(-1), freq. 100%) and trimethoprim (med. 0.05 microg L(-1), freq. 100%). Antibiotics identified in microfiltration/reverse osmosis product water included naladixic acid (med. 0.045 microg L(-1), freq. 100%), enrofloxacin (med. 0.01 microg L(-1), freq. 100%), roxithromycin (med. 0.01 microg L(-1), freq. 100%), norfloxacin (med. 0.005 microg L(-1), freq. 100%), oleandomycin (med. 0.005 microg L(-1), freq. 100%), trimethoprim (med. 0.005 microg L(-1), freq. 100%), tylosin (med. 0.001 microg L(-1), freq. 100%), and lincomycin (med. 0.001 microg L(-1), freq. 66%). Certain traditional parameters, including nitrate concentration, conductivity and turbidity of the effluent were assessed as predictors of total antibiotic concentration, however only conductivity demonstrated any correlation with total antibiotic concentration (p=0.018, r=0.7). There is currently a lack of information concerning the effects of these chemicals to critically assess potential risks for environmental discharge and water recycling.

  18. Antibiotic-modifying activity of riachin, a non-cyanogenic cyanoglycoside extracted from Bauhinia pentandra

    Directory of Open Access Journals (Sweden)

    Farias PAM

    2015-06-01

    Full Text Available Pablo Antonio Maia de Farias,1,3 Fernando Gomes Figueredo,2,3 Aline Maria Brito Lucas,3 Rafael Barbosa de Moura,3 Henrique Douglas Melo Coutinho,2 Tania Maria Sarmento da Silva,4 Ana Luiza de Aguiar Rocha Martin,2,3 Marta Maria de França Fonteles1 1Development and Technological Innovation in Medicines, Universidade Federal do Ceará – UFC, Fortaleza-CE, 2College of Biomedicine, Faculdade Leão Sampaio-FLS, 3College of Pharmacy, Faculdade de Medicina Estácio de Juazeiro do Norte-Estácio, Juazeiro do Norte-CE, 4Department of Molecular Sciences, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil Background: The search for new active compounds from the Brazilian flora has intensified in recent years, especially for new drugs with antibiotic potential. Accordingly, the aim of this study was to determine whether riachin has antibiotic activity in itself or is able to modulate the activity of conventional antibiotics.Methods: A non-cyanogenic cyanoglycoside known as riachin was isolated from Bauhinia pentandra, and was tested alone and in combination with three antibiotics (clindamycin, amikacin, and gentamicin against multiresistant bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.Results: Riachin did not show significant antibiotic activity when tested alone against any strain (P>0.05. However, when combined with conventional antibiotics, it showed drug-modifying activity against strains of S. aureus exposed to clindamycin (P<0.001 as well as against P. aeruginosa exposed to amikacin (P<0.001. Although riachin did not show direct antibiotic activity, it had synergistic activity when combined with amikacin or clindamycin. The mechanism of action of this synergism is under investigation.Conclusion: The results of this work demonstrate that some substances of natural origin can enhance the effectiveness of certain antibiotics, which means a substantial reduction in the drug dose required and

  19. Effects of oxytetracycline, tylosin, and amoxicillin antibiotics on specific methanogenic activity of anaerobic biomass

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2012-01-01

    Materials and Methods: To evaluate the inhibitory antibiotics amoxicillin, tetracycline, and tylosin on biomass activity, specific methanogenic activity (SMA using anerobic biomass batch; into 120 ml vials: 30 ml biomass and 70 ml substrate including volatile fatty acids, mainly acetic acid and various concentrations of antibiotics were added. Methane gas production replacement through solution of KOH (2 N as an absorber of CO 2 and bromine thymol blue as indicator was measured. Each batch was tested for 10 days. Results: Based on the findings, inhibitory concentration of oxytetracycline, amoxicillin, and tylosin were 8000, 9000, and 9000 mg/L, respectively. Conclusions: This study showed that with increasing concentrations of antibiotics, the produced biogas volume from biomass per unit weight is decreased. COD removal was 42-82 % due to long retention time and adsorption to flocks.

  20. Potentiation of aminoglycoside antibiotic activity using the body fat from the snake Boa constrictor

    Directory of Open Access Journals (Sweden)

    Felipe S. Ferreira

    2011-05-01

    Full Text Available Boa constrictor is widely used in traditional communities in many different folk remedies and products derived from it are sold in public markets throughout northeastern Brazil and as its body fat has many different therapeutic indications as a folk remedy. The present work evaluates the antibacterial activity of the body fat from the snake Boa constrictor when employed either alone or in combination with antibiotics and discusses the ecological implications of the use of this traditional remedy. Oil (OBC was extracted from body fat located in the ventral region of B. constrictor using hexane as a solvent. The antibacterial activity of OBC was tested against standard as well as multi-resistant lines, either alone and in combination with antibiotics. OBC did not demonstrate any relevant antibacterial activity against standard or multidrug-resistant bacterial strains. OBC showed synergistic activity when combined with the aminoglycoside antibiotics. Our results indicate that the body fat of Boa constrictor does not possess bactericidal activity, from the clinical point of view, but when combined with an antibiotic, the fat demonstrated a significant synergistic activity.

  1. Potentiation of aminoglycoside antibiotic activity using the body fat from the snake Boa constrictor

    Directory of Open Access Journals (Sweden)

    Felipe S. Ferreira

    2011-06-01

    Full Text Available Boa constrictor is widely used in traditional communities in many different folk remedies and products derived from it are sold in public markets throughout northeastern Brazil and as its body fat has many different therapeutic indications as a folk remedy. The present work evaluates the antibacterial activity of the body fat from the snake Boa constrictor when employed either alone or in combination with antibiotics and discusses the ecological implications of the use of this traditional remedy. Oil (OBC was extracted from body fat located in the ventral region of B. constrictor using hexane as a solvent. The antibacterial activity of OBC was tested against standard as well as multi-resistant lines, either alone and in combination with antibiotics. OBC did not demonstrate any relevant antibacterial activity against standard or multidrug-resistant bacterial strains. OBC showed synergistic activity when combined with the aminoglycoside antibiotics. Our results indicate that the body fat of Boa constrictor does not possess bactericidal activity, from the clinical point of view, but when combined with an antibiotic, the fat demonstrated a significant synergistic activity.

  2. Ozonation of norfloxacin and levofloxacin in water: Specific reaction rate constants and defluorination reaction.

    Science.gov (United States)

    Ling, Wencui; Ben, Weiwei; Xu, Ke; Zhang, Yu; Yang, Min; Qiang, Zhimin

    2018-03-01

    The degradation kinetics and mechanism of two typical fluoroquinolones (FQs), norfloxacin (NF) and levofloxacin (LOF), by ozone in water were investigated. Semi-continuous mode and competition kinetics mode experiments were conducted to determine the reaction rate constants of target FQs with ozone and OH, separately. Results indicate that both NF and LOF were highly reactive toward ozone, and the reactivity was strongly impacted by the solution pH. The specific reaction rate constants of the diprotonated, monoprotonated and deprotonated species were determined to be 7.20 × 10 2 , 8.59 × 10 3 , 4.54 × 10 5  M -1  s -1 respectively for NF and 1.30 × 10 3 , 1.40 × 10 4 , 1.33 × 10 6  M -1  s -1 respectively for LOF. The reaction rate constants of target FQs toward OH were measured to be (4.81-7.41) × 10 9  M -1  s -1 in the pH range of 6.3-8.3. Furthermore, NF was selected as a model compound to clarify the degradation pathways, with a particular focus on the defluorination reaction. The significant release of F - ions and the formation of three F-free organic byproducts indicated that defluorination was a prevalent pathway in ozonation of FQs, while six F-containing organic byproducts indicated that ozone also attacked the piperazinyl and quinolone moieties. Escherichia coli growth inhibition tests revealed that ozonation could effectively eliminate the antibacterial activity of target FQ solutions, and the residual antibacterial activity had a negative linear correlation with the released F - concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Antibacterial activity and safety of commercial veterinary cationic steroid antibiotics and neutral superoxidized water.

    Directory of Open Access Journals (Sweden)

    Benjamin E Bergstrom

    Full Text Available Antibiotic resistance of bacteria common to the ocular surface is an evolving problem. Thus, novel treatment options with new modes of action are required. We investigated the antibacterial activity and safety of three commercially available topical veterinary ophthalmic products (cationic steroid antibiotics, products A and B, and a neutral superoxidized water, product C to determine their potential use as antimicrobial alternatives. The minimum inhibitory concentrations (MIC of the three products were determined against 17 antibiotic resistant bacterial clinical isolates from the ocular surface. Using a standard cytotoxicity assay, the products at varying concentrations were evaluated with a corneal fibroblast cell line and a macrophage-like cell line to determine their potential toxic effect in vitro. The commercial ophthalmic solutions, ofloxacin 0.3%, tobramycin 0.3% and gentamicin 0.3% were used as positive controls for the MIC and tobramycin 0.3% was used as positive control for the cytotoxicity assays. For the MIC, Product C showed no inhibition of growth for any organisms, while Products A and B showed inhibition of growth similar to slightly less than the positive controls. For the cytotoxicity assays, Product C exhibited minimal toxicity while Products A and B exhibited toxicity similar to the controls. In conclusion, Product C had no antibacterial activity in these assays, while Products A and B had antibacterial profiles similar to slightly less than common topical ophthalmic antibiotics and cytotoxicity profiles similar to common topical ophthalmic antibiotics. To our knowledge, this is the first report on the antibacterial activity and safety of the cationic steroid antibiotics and superoxidized water.

  4. Biotransformation of fluoroquinolone antibiotics by ligninolytic fungi - Metabolites, enzymes and residual antibacterial activity

    Czech Academy of Sciences Publication Activity Database

    Čvančarová, Monika; Moeder, M.; Filipová, Alena; Cajthaml, Tomáš

    2015-01-01

    Roč. 136, OCT 2015 (2015), s. 311-320 ISSN 0045-6535 R&D Projects: GA TA ČR TE01020218; GA ČR GA13-28283S Institutional support: RVO:61388971 Keywords : Fluoroquinolone antibiotics * White rot fungi * Residual antibacterial activity Subject RIV: EE - Microbiology, Virology Impact factor: 3.698, year: 2015

  5. Martinomycin, a new polyether antibiotic produced by Streptomyces salvialis. I. Taxonomy, fermentation and biological activity.

    Science.gov (United States)

    Bernan, V S; Montenegro, D A; Goodman, J J; Alluri, M R; Carter, G T; Abbanat, D R; Pearce, C J; Maiese, W M; Greenstein, M

    1994-12-01

    Actinomycete culture LL-D37187 has been found to produce the new polyether antibiotic martinomycin. Taxonomic studies, including morphological, physiological, and cell wall chemistry analyses, revealed that culture LL-D37187 is a novel streptomycete species, and the proposed name is Streptomyces salvialis. Martinomycin exhibits activity against the Southern Army Worm (Spodoptera eridania) and Gram-positive bacteria.

  6. Berberine Enhances the Antibacterial Activity of Selected Antibiotics against Coagulase-Negative Staphylococcus Strains in Vitro

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    Robert D. Wojtyczka

    2014-05-01

    Full Text Available Synergistic interactions between commonly used antibiotics and natural bioactive compounds may exhibit therapeutic benefits in a clinical setting. Berberine, an isoquinoline-type alkaloid isolated from many kinds of medicinal plants, has proven efficacy against a broad spectrum of microorganisms. The aim of the presented work was to assess the antibacterial activity of berberine chloride in light of the effect exerted by common antibiotics on fourteen reference strains of Staphylococccus spp., and to evaluate the magnitude of interactions of berberine with these antistaphylococcal antibiotics. In our study minimum inhibitory concentrations (MIC of berberine chloride against CoNS ranged from 16 to 512 µg/mL. The most noticeable effects were observed for S. haemolyticus ATCC 29970, S. epidermidis ATCC 12228, S. capitis subsp. capitis ATCC 35661, S. galinarium ATCC 700401, S. hominis subsp. hominis ATCC 27844, S. intermedius ATCC 29663 and S. lugdunensis ATCC 49576. The most significant synergistic effect was noticed for berberine in combination with linezolid, cefoxitin and erythromycin. The synergy between berberine and antibiotics demonstrates the potential application of compound combinations as an efficient, novel therapeutic tool for antibiotic-resistant bacterial infections.

  7. Berberine enhances the antibacterial activity of selected antibiotics against coagulase-negative Staphylococcus strains in vitro.

    Science.gov (United States)

    Wojtyczka, Robert D; Dziedzic, Arkadiusz; Kępa, Małgorzata; Kubina, Robert; Kabała-Dzik, Agata; Mularz, Tomasz; Idzik, Danuta

    2014-05-22

    Synergistic interactions between commonly used antibiotics and natural bioactive compounds may exhibit therapeutic benefits in a clinical setting. Berberine, an isoquinoline-type alkaloid isolated from many kinds of medicinal plants, has proven efficacy against a broad spectrum of microorganisms. The aim of the presented work was to assess the antibacterial activity of berberine chloride in light of the effect exerted by common antibiotics on fourteen reference strains of Staphylococccus spp., and to evaluate the magnitude of interactions of berberine with these antistaphylococcal antibiotics. In our study minimum inhibitory concentrations (MIC) of berberine chloride against CoNS ranged from 16 to 512 µg/mL. The most noticeable effects were observed for S. haemolyticus ATCC 29970, S. epidermidis ATCC 12228, S. capitis subsp. capitis ATCC 35661, S. galinarium ATCC 700401, S. hominis subsp. hominis ATCC 27844, S. intermedius ATCC 29663 and S. lugdunensis ATCC 49576. The most significant synergistic effect was noticed for berberine in combination with linezolid, cefoxitin and erythromycin. The synergy between berberine and antibiotics demonstrates the potential application of compound combinations as an efficient, novel therapeutic tool for antibiotic-resistant bacterial infections.

  8. Bioavailability of Antibiotics at Soil-Water Interfaces: A Comparison of Measured Activities and Equilibrium Partitioning Estimates.

    Science.gov (United States)

    Menz, Jakob; Müller, Julia; Olsson, Oliver; Kümmerer, Klaus

    2018-06-05

    There are growing concerns that antibiotic pollution impacts environmental microbiota and facilitates the propagation of antibiotic resistance. However, the prediction or analytical determination of bioavailable concentrations of antibiotics in soil is still subject to great uncertainty. Biological assays are increasingly recognized as valuable complementary tools that allow a more direct determination of the residual antibiotic activity. This study assessed the bioavailability of structurally diverse antibiotics at a soil-water interface applying activity-based analyses in conjunction with equilibrium partitioning (EqP) modeling. The activity against Gram-positive and Gram-negative bacteria of nine antibiotics from different classes was determined in the presence and absence of standard soil (LUFA St. 2.2). The addition of soil affected the activity of different antibiotics to highly varying degrees. Moreover, a highly significant correlation ( p < 0.0001) between the experimentally observed and the EqP-derived log EC 50 (half-maximal effective concentration) values was observed. The innovative experimental design of this study provided new insights on the bioavailability of antibiotics at soil-water interfaces. EqP appears to be applicable to a broad range of antibiotics for the purpose of screening-level risk assessment. However, EqP estimates cannot replace soil-specific ecotoxicity testing in higher-tier assessments, since their accuracy is still compromised by a number of factors.

  9. Stability and Activities of Antibiotics Produced during Infection of the Insect Galleria mellonella by Two Isolates of Xenorhabdus nematophilus

    OpenAIRE

    Maxwell, Philip W.; Chen, Genhui; Webster, John M.; Dunphy, Gary B.

    1994-01-01

    Xenorhabdus nematophilus subsp. dutki, an entomopathogenic bacterium, is vectored by steinernematid nematodes into insects, where it produces broad-spectrum antibiotics. The use of the nematode-bacterium complex against soil-dwelling pest insects could introduce antibiotics into the soil via the dead insect fragments during the emergence phase of the nematodes. Studies on the stability and activities of these antibiotics produced in the insect Galleria mellonella may contribute to assessing t...

  10. Redox-active antibiotics control gene expression and community behavior in divergent bacteria.

    Science.gov (United States)

    Dietrich, Lars E P; Teal, Tracy K; Price-Whelan, Alexa; Newman, Dianne K

    2008-08-29

    It is thought that bacteria excrete redox-active pigments as antibiotics to inhibit competitors. In Pseudomonas aeruginosa, the endogenous antibiotic pyocyanin activates SoxR, a transcription factor conserved in Proteo- and Actinobacteria. In Escherichia coli, SoxR regulates the superoxide stress response. Bioinformatic analysis coupled with gene expression studies in P. aeruginosa and Streptomyces coelicolor revealed that the majority of SoxR regulons in bacteria lack the genes required for stress responses, despite the fact that many of these organisms still produce redox-active small molecules, which indicates that redox-active pigments play a role independent of oxidative stress. These compounds had profound effects on the structural organization of colony biofilms in both P. aeruginosa and S. coelicolor, which shows that "secondary metabolites" play important conserved roles in gene expression and development.

  11. Pathogen- and Host-Directed Anti-Inflammatory Activities of Macrolide Antibiotics

    OpenAIRE

    Steel, Helen C.; Theron, Annette J.; Cockeran, Riana; Anderson, Ronald; Feldman, Charles

    2012-01-01

    Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmfu...

  12. Synergistic anti-Campylobacter jejuni activity of fluoroquinolone and macrolide antibiotics with phenolic compounds

    Science.gov (United States)

    Oh, Euna; Jeon, Byeonghwa

    2015-01-01

    The increasing resistance of Campylobacter to clinically important antibiotics, such as fluoroquinolones and macrolides, is a serious public health problem. The objective of this study is to investigate synergistic anti-Campylobacter jejuni activity of fluoroquinolones and macrolides in combination with phenolic compounds. Synergistic antimicrobial activity was measured by performing a checkerboard assay with ciprofloxacin and erythromycin in the presence of 21 phenolic compounds. Membrane permeability changes in C. jejuni by phenolic compounds were determined by measuring the level of intracellular uptake of 1-N-phenylnaphthylamine (NPN). Antibiotic accumulation assays were performed to evaluate the level of ciprofloxacin accumulation in C. jejuni. Six phenolic compounds, including p-coumaric acid, sinapic acid, caffeic acid, vanillic acid, gallic acid, and taxifolin, significantly increased the susceptibility to ciprofloxacin and erythromycin in several human and poultry isolates. The synergistic antimicrobial effect was also observed in ciprofloxacin- and erythromycin-resistant C. jejuni strains. The phenolic compounds also substantially increased membrane permeability and antibiotic accumulation in C. jejuni. Interestingly, some phenolic compounds, such as gallic acid and taxifolin, significantly reduced the expression of the CmeABC multidrug efflux pump. Phenolic compounds increased the NPN accumulation in the cmeB mutant, indicating phenolic compounds may affect the membrane permeability. In this study, we successfully demonstrated that combinational treatment of C. jejuni with antibiotics and phenolic compounds synergistically inhibits C. jejuni by impacting both antimicrobial influx and efflux. PMID:26528273

  13. The activity of aminoglycoside antibiotics against Trypanosoma brucei.

    Science.gov (United States)

    Maina, N W; Kinyanjui, B; Onyango, J D; Auma, J E; Croj, S

    1998-01-01

    The trypanocidal activity of four aminoglycosides was determined against Trypanosoma brucei in vitro. The drug activity in descending order, was as follows; paromomycin kanamycin>gentamycin > neomycin. Paromomycin bad the highest activity and the concentration that inhibited 50% of trypanosome growth (IC50) was 11.4microM. The effect of paromomycin on the causative agents of the East African form of sleeping sickness - T.b. rhodesiense KETRI 265, 2285, 2545, 2562 and EATRO 110,112, 1152 was subsequently assessed. Variations sensitivities between the trypanosome populations were observed and IC50 values ranging from 13.01 to 43.06 microM recorded. However, when paromomycin was administered intraperitoneally (i.p) at 500 mg/kg, it was not effective in curing mice infected with T. b. rhodesienseKETRI 2545 the most drug-sensitive isolate in vitro. Lack of in vivo activity may be because the trypanosome is an extracellular parasite. The pharmacokinetics of paromomycin in the mouse model need to be determined.

  14. Synthesis and Antibiotic Activity of Mebendazole Derivatives of Pharmacological Interest

    Directory of Open Access Journals (Sweden)

    Kavita Rathore

    2007-01-01

    Full Text Available Mebendazole is a well known anti-helimintic and belongs to the benzimidazole group of medicines. In order to achieve better medicinal results, i.e. enhanced activity and low toxicity, structural modifications are made in the existing drugs. Some 5-benzoyl-N-[1-(alkoxyphthalimido benzimidazol-2-yl] carbamic acid methyl ester (3a-c and 5-benzoyl-N-[1-(2,3-bis oxyphthalimido∕oxysuccinimido propyl benzimidazol-2-yl carbamic acid methyl ester (7a-b have been synthesized from two different routes. Structures of the compounds have been established on the basis of elemental analysis and spectral studies. All the synthesized compounds (3a-c and (7a-b were assayed in vitro for antimicrobial activity against mebendazole (itself and standard [ciprofloxacin (antibacterial and fluconazole (antifungal].

  15. Granular activated carbon assisted ozonation of cephalexin antibiotic

    International Nuclear Information System (INIS)

    Akhtar, J.; Amin, N.S.; Imran, M.

    2016-01-01

    This study investigates removal of cephalexin using ozonation in the presence of granular activated carbon. Initial experiments were carried out about adsorption of cephalexin onto granular activated carbon, effect of catalytic ozonation, and biodegradability of cephalexin solution. The effect of ozonation on pH, ozone utilization efficiency and decomposition byproducts, was observed. Response surface methodology was adopted to optimize three operating parameters pH of solution, ozone supply and cephalexin concentration. GAC assisted ozonation, was found to be effective in decomposing COD (chemical oxygen demand) and cephalexin from solution. Optimum values of variables were pH from 7-8, ozone supply 30 mg/L and 100 mg/L of cephalexin solution. The complete removal of cephalexin and 60% COD removal was achieved at these optimum input values. (author)

  16. Enhancement of norfloxacin solubility via inclusion complexation with β-cyclodextrin and its derivative hydroxypropyl-β-cyclodextrin

    Directory of Open Access Journals (Sweden)

    Gabriel Onn Kit Loh

    2016-08-01

    Full Text Available The objectives of the study were to investigate the effects of β-cyclodextrin (βCD and hydroxypropyl-β-cyclodextrin (HPβCD on the solubility and dissolution rate of norfloxacin prepared using three different methods, at drug to cyclodextrin weight ratios of 1:1, 1:2, 1:4 and 1:8. All the methods increased the solubility and dissolution rate of norfloxacin via inclusion complexation with βCD and HPβCD. Norfloxacin was converted from crystalline to amorphous form through inclusion complexation. Solvent evaporation method was the most effective method in terms of norfloxacin solubilisation, while inclusion complex of HPβCD has higher solubility than βCD complex when prepared using the same procedure.

  17. Epilobi Hirsuti Herba Extracts Influence the In Vitro Activity of Common Antibiotics on Standard Bacteria

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    Pirvu Lucia

    2016-01-01

    Full Text Available Epilobium genus has been confirmed as an effective source of natural antimicrobials. However, the influence of Epilobi hirsuti herba derived products on usual antibiotics activity has not been studied. In this study, several standardized Epilobi hirsuti herba extracts (EHE were evaluated in order to asses their potential effects on usual antibiotics tested on standard Gram-positive and Gram-negative bacterial strains in vitro. The results emphasized that the bacterial strains ranged from sensitive (MIC values between 50–200 μg GAE mL-1 (S. epidermidis ATCC 12228 to very resistant (E. coli strains, E. faecalis ATCC 29212 being practically immune to EHE. In terms of synergistic interaction, Tetracycline and Ampicillin combinations lead to the most important stimulatory effects, the diameters of the inhibition zone being even 60% bigger compared to the antibiotic alone. Synergistic effects between myricetin(galloyl derivates and Tetracycline were also revealed on P. aeruginosa and E. coli strains. Together, it clearly demonstrated not only EHE’s own antimicrobial properties, but also their capacity to influence the antimicrobial potency of some common antibiotics. These results could be useful for the area of herbal medicines and as potential candidates in managing microbial resistance, but also for physicians and pharmacists using combined antibacterial therapy.

  18. Antibacterial Activity and Antibiotic-Enhancing Effects of Honeybee Venom against Methicillin-Resistant Staphylococcus aureus

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    Sang Mi Han

    2016-01-01

    Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA, along with other antibiotic resistant bacteria, has become a significant social and clinical problem. There is thus an urgent need to develop naturally bioactive compounds as alternatives to the few antibiotics that remain effective. Here we assessed the in vitro activities of bee venom (BV, alone or in combination with ampicillin, penicillin, gentamicin or vancomycin, on growth of MRSA strains. The antimicrobial activity of BV against MRSA strains was investigated using minimum inhibitory concentrations (MIC, minimum bactericidal concentrations (MBC and a time-kill assay. Expression of atl which encodes murein hydrolase, a peptidoglycan-degrading enzyme involved in cell separation, was measured by reverse transcription-polymerase chain reaction. The MICs of BV were 0.085 µg/mL and 0.11 µg/mL against MRSA CCARM 3366 and MRSA CCARM 3708, respectively. The MBC of BV against MRSA 3366 was 0.106 µg/mL and that against MRSA 3708 was 0.14 µg/mL. The bactericidal activity of BV corresponded to a decrease of at least 3 log CFU/g cells. The combination of BV with ampicillin or penicillin yielded an inhibitory concentration index ranging from 0.631 to 1.002, indicating a partial and indifferent synergistic effect. Compared to ampicillin or penicillin, both MRSA strains were more susceptible to the combination of BV with gentamicin or vancomycin. The expression of atl gene was increased in MRSA 3366 treated with BV. These results suggest that BV exhibited antibacterial activity and antibiotic-enhancing effects against MRSA strains. The atl gene was increased in MRSA exposed to BV, suggesting that cell division was interrupted. BV warrants further investigation as a natural antimicrobial agent and synergist of antibiotic activity.

  19. Polycyclic Polyprenylated Acylphloroglucinols: An Emerging Class of Non-Peptide-Based MRSA- and VRE-Active Antibiotics.

    Science.gov (United States)

    Guttroff, Claudia; Baykal, Aslihan; Wang, Huanhuan; Popella, Peter; Kraus, Frank; Biber, Nicole; Krauss, Sophia; Götz, Friedrich; Plietker, Bernd

    2017-12-11

    In the past 20 years, peptide-based antibiotics, such as vancomycin, teicoplanin, and daptomycin, have often been considered as second-line antibiotics. However, in recent years, an increasing number of reports on vancomycin resistance in pathogens appeared, which forces researchers to find novel lead structures for potent new antibiotics. Herein, we report the total synthesis of a defined endo-type B PPAP library and their antibiotic activity against multiresistant S. aureus and various vancomycin-resistant Enterococci. Four new compounds that combine high activities and low cytotoxicity were identified, indicating that the PPAP core might become a new non-peptide-based lead structure in antibiotic research. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Collateral sensitivity between aminoglycosides and beta-lactam antibiotics depends on active proton pumps.

    Science.gov (United States)

    Azimi, Leila; Rastegar Lari, Abdolaziz

    2017-11-01

    Selection inversion is the hypothesis for antibiotic resistant inhabitation in bacteria and collateral sensitivity is one of the proposed phenomena for achievement of this hypothesis. The presence of collateral sensitivity associated with the proton motivation pump between the aminoglycosides and beta-lactam group of antibiotics is one of the examples of collateral sensitivity in some studies. The aim of this study was to demonstrate that collateral sensitivity between aminoglycosides and beta-lactam antibiotics associated with proton motivation pump may not be true in all cases. In this study, 100 Pseudomonas aeruginosa were surveyed. Gentamicin and imipenem-resistant strains were confirmed by disc diffusion method and MIC. Active proton motivation pumps were screened by pumps inhibitor. Semi-quantitative Real-Time PCR assay was used to confirm gene overexpression. Seventy-six and 79 out of 100 strains were resistant to gentamicin and imipenem, respectively. Seventy-five strains were resistant to both gentamicin and imipenem. The results of proton pump inhibitor test showed the involvement of active proton motivation pump in 22 of 75 imipenem- and gentamicin-resistant strains. According to Real - Time PCR assay, mexX efflux gene was overexpressed in the majority of isolates tested. The collateral sensitivity effect cannot explain the involvement of active proton motivation pumps in both imipenem and gentamicin-resistant strains simultaneously. Active and/or inactive proton pump in gentamicin-sensitive and/or resistant strains cannot be a suitable example for explanation of collateral sensitivity between aminoglycosides and beta-lactam antibiotics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Penicillin-Bound Polyacrylate Nanoparticles: Restoring the Activity of β-Lactam Antibiotics Against MRSA

    OpenAIRE

    Turos, Edward; Reddy, G. Suresh Kumar; Greenhalgh, Kerriann; Ramaraju, Praveen; Abeylath, Sampath C.; Jang, Seyoung; Dickey, Sonja; Lim, Daniel V.

    2007-01-01

    This report describes the preparation of antibacterially-active emulsified polyacrylate nanoparticles in which a penicillin antibiotic is covalently conjugated onto the polymeric framework. These nanoparticles were prepared in water by emulsion polymerization of an acrylated penicillin analogue pre-dissolved in a 7:3 (w:w) mixture of butyl acrylate and styrene in the presence of sodium dodecyl sulfate (surfactant) and potassium persulfate (radical initiator). Dynamic light scattering analysis...

  2. Synergistic activity of antibiotics combined with ivermectin to kill body lice.

    Science.gov (United States)

    Sangaré, Abdoul Karim; Rolain, Jean Marc; Gaudart, Jean; Weber, Pascal; Raoult, Didier

    2016-03-01

    Ivermectin and doxycycline have been found to be independently effective in killing body lice. In this study, 450 body lice were artificially fed on a Parafilm™ membrane with human blood associated with antibiotics (doxycycline, erythromycin, rifampicin and azithromycin) alone and in combination with ivermectin. Fluorescence in situ hybridisation and spectral deconvolution were performed to evaluate bacterial transcriptional activity following antibiotic intake by the lice. In the first series, a lethal effect of antibiotics on lice was observed compared with the control group at 18 days (log-rank test, P≤10(-3)), with a significant difference between groups in the production of nits (P=0.019, Kruskal-Wallis test). A high lethal effect of ivermectin alone (50ng/mL) was observed compared with the control group (log-rank test, P≤10(-3)). Fluorescence of bacteriocytes in lice treated with 20μg/mL doxycycline was lower than in untreated lice (PKruskal-Wallis test). In the second series with antibiotic-ivermectin combinations, a synergistic lethal effect on treated lice (log-rank test, PKruskal-Wallis test). Additionally, survival of lice in the combination treatment groups compared with ivermectin alone was significant (log-rank test, P=0.0008). These data demonstrate that the synergistic effect of combinations of antibiotics and ivermectin could be used to achieve complete eradication of lice and to avoid selection of a resistant louse population. Copyright © 2016 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  3. Antibiotics and activity spaces: protocol of an exploratory study of behaviour, marginalisation and knowledge diffusion

    Science.gov (United States)

    Charoenboon, Nutcha; Zanello, Giacomo; Mayxay, Mayfong; Reed-Tsochas, Felix; Jones, Caroline O H; Kosaikanont, Romyen; Praphattong, Pollavat; Manohan, Pathompong; Lubell, Yoel; Newton, Paul N; Keomany, Sommay; Wertheim, Heiman F L; Lienert, Jeffrey; Xayavong, Thipphaphone; Warapikuptanun, Penporn; Khine Zaw, Yuzana; U-Thong, Patchapoom; Benjaroon, Patipat; Sangkham, Narinnira; Wibunjak, Kanokporn; Chai-In, Poowadon; Chailert, Sirirat; Thavethanutthanawin, Patthanan; Promsutt, Krittanon; Thepkhamkong, Amphayvone; Sithongdeng, Nicksan; Keovilayvanh, Maipheth; Khamsoukthavong, Nid; Phanthasomchit, Phaengnitta; Phanthavong, Chanthasone; Boualaiseng, Somsanith; Vongsavang, Souksakhone; Greer, Rachel C; Althaus, Thomas; Nedsuwan, Supalert; Intralawan, Daranee; Wangrangsimakul, Tri; Limmathurotsakul, Direk; Ariana, Proochista

    2018-01-01

    Background Antimicrobial resistance (AMR) is a global health priority. Leading UK and global strategy papers to fight AMR recognise its social and behavioural dimensions, but current policy responses to improve the popular use of antimicrobials (eg, antibiotics) are limited to education and awareness-raising campaigns. In response to conceptual, methodological and empirical weaknesses of this approach, we study people’s antibiotic-related health behaviour through three research questions. RQ1: What are the manifestations and determinants of problematic antibiotic use in patients’ healthcare-seeking pathways? RQ2: Will people’s exposure to antibiotic awareness activities entail changed behaviours that diffuse or dissipate within a network of competing healthcare practices? RQ3: Which proxy indicators facilitate the detection of problematic antibiotic behaviours across and within communities? Methods We apply an interdisciplinary analytical framework that draws on the public health, medical anthropology, sociology and development economics literature. Our research involves social surveys of treatment-seeking behaviour among rural dwellers in northern Thailand (Chiang Rai) and southern Lao PDR (Salavan). We sample approximately 4800 adults to produce district-level representative and social network data. Additional 60 cognitive interviews facilitate survey instrument development and data interpretation. Our survey data analysis techniques include event sequence analysis (RQ1), multilevel regression (RQ1–3), social network analysis (RQ2) and latent class analysis (RQ3). Discussion Social research in AMR is nascent, but our unprecedentedly detailed data on microlevel treatment-seeking behaviour can contribute an understanding of behaviour beyond awareness and free choice, highlighting, for example, decision-making constraints, problems of marginalisation and lacking access to healthcare and competing ideas about desirable behaviour. Trial registration number NCT

  4. Demographics of antibiotic persistence

    DEFF Research Database (Denmark)

    Kollerova, Silvia; Jouvet, Lionel; Steiner, Ulrich

    Persister cells, cells that can survive antibiotic exposure but lack heritable antibiotic resistance, are assumed to play a crucial role for the evolution of antibiotic resistance. Persistence is a stage associated with reduced metabolic activity. Most previous studies have been done on batch...... even play a more prominent role for the evolution of resistance and failures of medical treatment by antibiotics as currently assumed....

  5. In vitro susceptibilities of Brucella melitensis isolates to eleven antibiotics

    Directory of Open Access Journals (Sweden)

    Loukaides Feidias

    2006-10-01

    Full Text Available Abstract Background Brucellosis is an endemic disease present in many countries worldwide, but it is rare in Europe and North America. Nevertheless brucella is included in the bacteria potentially used for bioterrorism. The aim of this study was the investigation of the antibiotic susceptibility profile of brucella isolates from areas of the eastern Mediterranean where it has been endemic. Methods The susceptibilities of 74 Brucella melitensis isolates derived from clinical samples (57 and animal products (17 were tested in vitro. The strains originate from Crete (59, Cyprus (10, and Syria (5. MICs of tetracycline, rifampicin, streptomycin, gentamicin, norfloxacin, ciprofloxacin, levofloxacin, trimethoprim/sulfamethoxazole, ampicillin, amoxicillin/clavulanic acid, and erythromycin were detected by E-test method. The NCCLS criteria for slow growing bacteria were considered to interpret the results. Results All the isolates were susceptible to tetracycline, streptomycin, gentamicin, ciprofloxacin, norfloxacin, and levofloxacin. Two isolates presented reduced susceptibility to rifampicin (MIC value: 1.5 mg/l and eight to SXT (MIC values: 0.75–1.5 mg/l. Erythromycin had the highest (4 mg/l MIC90value and both norfloxacin and erythromycin the highest (1.5 mg/l MIC50 value. Conclusion Brucella isolates remain susceptible in vitro to most antibiotics used for treatment of brucellosis. The establishment of a standardized antibiotic susceptibility method for Brucella spp would be useful for resistance determination in these bacteria and possible evaluation of bioterorism risks.

  6. Diminished Antimicrobial Peptide and Antifungal Antibiotic Activities against Candida albicans in Denture Adhesive

    Directory of Open Access Journals (Sweden)

    Amber M. Bates

    2017-02-01

    Full Text Available The underlying causes of denture stomatitis may be related to the long-term use of adhesives, which may predispose individuals to oral candidiasis. In this study, we hypothesize that antimicrobial peptides and antifungal antibiotics have diminished anti-Candida activities in denture adhesive. To show this, nine antimicrobial peptides and five antifungal antibiotics with and without 1.0% denture adhesive were incubated with Candida albicans strains ATCC 64124 and HMV4C in radial diffusion assays. In gels with 1.0% adhesive, HNP-1, HBD2, HBD3, IP-10, LL37 (only one strain, histatin 5 (only one strain, lactoferricin B, and SMAP28 showed diminished activity against C. albicans. In gels with 1.0% adhesive, amphotericin B and chlorhexidine dihydrochloride were active against both strains of C. albicans. These results suggest that denture adhesive may inactivate innate immune mediators in the oral cavity increasing the risk of C. albicans infections, but inclusion of antifungal antibiotics to denture adhesive may aid in prevention or treatment of Candida infections and denture stomatitis.

  7. Antagonistic activity of antibiotic producing Streptomyces sp. against fish and human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Nazmul Hossain

    2014-04-01

    Full Text Available In this study, attempts were made to isolate Streptomyces sp. from soil samples of two different regions of Bangladesh and evaluate their antagonistic activity against fish and human pathogenic bacteria. A total of 10 isolates were identified as Streptomyces sp. based on several morphological, physiological and biochemical tests. Cross streak method was used to observe the antagonistic activity of the Streptomyces sp. isolates against different fish pathogens belonging to the genus Aeromonas, Pseudomonas and Edwardsiella and human clinical isolates belonging to the genus Klebsiella, Salmonella and Streptococcus. Seven Streptomyces sp. isolates showed antagonism against both fish and human pathogenic bacteria. Four isolates viz., N24, N26, N28 and N47 showed broad spectrum of antagonistic activity (80-100% against all genera of fish and human pathogenic bacteria. The isolate N49 exhibited highest spectrum of antagonism against all fish pathogens (90-100% but comparatively lower degree of antagonism against human pathogens (50-60%. Rest of the two isolates (N21 and N23 showed variability in their antagonism. Results showed that broad spectrum antibiotic(s could be developed from the isolates N24, N26, N28 and N47against several human and fish pathogens. The isolate N49 could be a potential source of antibiotic, especially for fish pathogenic bacteria.

  8. Antimicrobial activity of filamentous fungi isolated from highly antibiotic-contaminated river sediment

    Science.gov (United States)

    Svahn, K. Stefan; Göransson, Ulf; El-Seedi, Hesham; Bohlin, Lars; Larsson, D.G. Joakim; Olsen, Björn; Chryssanthou, Erja

    2012-01-01

    Background Filamentous fungi are well known for their production of substances with antimicrobial activities, several of which have formed the basis for the development of new clinically important antimicrobial agents. Recently, environments polluted with extraordinarily high levels of antibiotics have been documented, leading to strong selection pressure on local sentinel bacterial communities. In such microbial ecosystems, where multidrug-resistant bacteria are likely to thrive, it is possible that certain fungal antibiotics have become less efficient, thus encouraging alternative strategies for fungi to compete with bacteria. Methods In this study, sediment of a highly antibiotic-contaminated Indian river was sampled in order to investigate the presence of cultivable filamentous fungi and their ability to produce substances with antimicrobial activity. Results Sixty one strains of filamentous fungi, predominantly various Aspergillus spp. were identified. The majority of the Aspergillus strains displayed antimicrobial activity against methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase-producing Escherichia coli, vancomycin-resistant Enterococcus faecalis and Candida albicans. Bioassay-guided isolation of the secondary metabolites of A. fumigatus led to the identification of gliotoxin. Conclusion This study demonstrated proof of principle of using bioassay-guided isolation for finding bioactive molecules. PMID:22957125

  9. Antimicrobial activity of filamentous fungi isolated from highly antibiotic-contaminated river sediment

    Directory of Open Access Journals (Sweden)

    K. Stefan Svahn

    2012-05-01

    Full Text Available Background: Filamentous fungi are well known for their production of substances with antimicrobial activities, several of which have formed the basis for the development of new clinically important antimicrobial agents. Recently, environments polluted with extraordinarily high levels of antibiotics have been documented, leading to strong selection pressure on local sentinel bacterial communities. In such microbial ecosystems, where multidrug-resistant bacteria are likely to thrive, it is possible that certain fungal antibiotics have become less efficient, thus encouraging alternative strategies for fungi to compete with bacteria. Methods: In this study, sediment of a highly antibiotic-contaminated Indian river was sampled in order to investigate the presence of cultivable filamentous fungi and their ability to produce substances with antimicrobial activity. Results: Sixty one strains of filamentous fungi, predominantly various Aspergillus spp. were identified. The majority of the Aspergillus strains displayed antimicrobial activity against methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase-producing Escherichia coli, vancomycin-resistant Enterococcus faecalis and Candida albicans. Bioassay-guided isolation of the secondary metabolites of A. fumigatus led to the identification of gliotoxin. Conclusion: This study demonstrated proof of principle of using bioassay-guided isolation for finding bioactive molecules.

  10. European Antibiotic Awareness Day, 2008 - the first Europe-wide public information campaign on prudent antibiotic use: methods and survey of activities in participating countries.

    Science.gov (United States)

    Earnshaw, S; Monnet, D L; Duncan, B; O'Toole, J; Ekdahl, K; Goossens, H

    2009-07-30

    Antibiotic resistance is a major European and global public health problem and is, for a large part, driven by misuse of antibiotics. Hence, reducing unnecessary antibiotic use, particularly for the treatment of certain respiratory tract infections where they are not needed, is a public health priority. The success of national awareness campaigns to educate the public and primary care prescribers about appropriate antibiotic use in Belgium and France stimulated a European initiative coordinated by the European Centre for Disease Prevention and Control (ECDC), and named European Antibiotic Awareness Day (EAAD), to take place each year on 18 November. Specific campaign materials, including key messages, logos, slogans and a media toolkit, were developed and made available for use in European countries. The focus of the first EAAD campaign was about not taking antibiotics for viral infections such as colds and flu. A post-campaign survey was conducted in January 2009. Thirty-two European countries participated in the first EAAD, producing information materials and implementing activities to mark EAAD. Media coverage peaked on 18 and 19 November. At EU level, EAAD was launched at a scientific meeting in the European Parliament, Strasbourg. The event received EU political engagement through support from the EU Commissioner for Health, the Slovenian and French EU Presidencies, and Members of the European Parliament. Critical factors that led to the success of the first EAAD were good cooperation and process for building the campaign, strong political and stakeholder support and development of campaign materials based on scientific evidence. Countries indicated wide support for another EAAD in 2009. For this purpose, ECDC is developing several TV spots as well as a second set of EAAD campaign materials targeting primary care prescribers.

  11. Temporal relationship between antibiotic use and respiratory virus activities in the Republic of Korea: a time-series analysis.

    Science.gov (United States)

    Ryu, Sukhyun; Kim, Sojung; Kim, Bryan I; Klein, Eili Y; Yoon, Young Kyung; Chun, Byung Chul

    2018-01-01

    Inappropriate use of antibiotics increases resistance and reduces their effectiveness. Despite evidence-based guidelines, antibiotics are still commonly used to treat infections likely caused by respiratory viruses. In this study, we examined the temporal relationships between antibiotic usage and respiratory infections in the Republic of Korea. The number of monthly antibiotic prescriptions and the incidence of acute respiratory tract infections between 2010 and 2015 at all primary care clinics were obtained from the Korean Health Insurance Review and Assessment Service. The monthly detection rates of respiratory viruses, including adenovirus, respiratory syncytial virus, influenza virus, human coronavirus, and human rhinovirus, were collected from Korea Centers for Disease Control and Prevention. Cross-correlation analysis was conducted to quantify the temporal relationship between antibiotic use and respiratory virus activities as well as respiratory infections in primary clinics. The monthly use of different classes of antibiotic, including penicillins, other beta-lactam antibacterials, macrolides and quinolones, was significantly correlated with influenza virus activity. These correlations peaked at the 0-month lag with cross-correlation coefficients of 0.45 ( p  < 0.01), 0.46 ( p  < 0.01), 0.40 ( p  < 0.01), and 0.35 (< 0.01), respectively. Furthermore, a significant correlation was found between acute bronchitis and antibiotics, including penicillin (0.73, p  < 0.01), macrolides (0.74, p  < 0.01), and quinolones (0.45, p  < 0.01), at the 0-month lag. Our findings suggest that there is a significant temporal relationship between influenza virus activity and antibiotic use in primary clinics. This relationship indicates that interventions aimed at reducing influenza cases in addition to effort to discourage the prescription of antibiotics by physicians may help to decrease unnecessary antibiotic consumption.

  12. Antibacterial, modulatory activity of antibiotics and toxicity from Rhinella jimi (Stevaux, 2002) (Anura: Bufonidae) glandular secretions.

    Science.gov (United States)

    Sales, Débora Lima; Morais-Braga, Maria Flaviana Bezerra; Santos, Antonia Thassya Lucas Dos; Machado, Antonio Judson Targino; Araujo Filho, João Antonio de; Dias, Diógenes de Queiroz; Cunha, Francisco Assis Bezerra da; Saraiva, Rogério de Aquino; Menezes, Irwin Rose Alencar de; Coutinho, Henrique Douglas Melo; Costa, José Galberto Martins; Ferreira, Felipe Silva; Alves, Rômulo Romeu da Nóbrega; Almeida, Waltécio de Oliveira

    2017-08-01

    The increase in microorganisms with resistance to medications has caused a strong preoccupation within the medical and scientific community. Animal toxins studies, such as parotoid glandular secretions from amphibians, possesses a great potential in the development of drugs, such as antimicrobials, as these possess bioactive compounds. It was evaluated Rhinella jimi (Stevaux, 2002) glandular secretions against standard and multi-resistant bacterial strains; the effect of secretions combined with drugs; and determined the toxicity using two biologic in vivo models, and a in vitro model with mice livers. Standard strains were used for the determination of the Minimum Inhibitory Concentration (MIC), while for the modulatory activity of antibiotics, the clinical isolates Escherichia coli 06, Pseudomonas aeruginosa 03 and Staphylococcus aureus 10 were used. Modulatory activity was evaluated by the broth microdilution method with aminoglycosides and β-lactams as target antibiotics. The secretions in association with the antibiotics have a significant reduction in MIC, both the aminoglycosides and β-lactams. The toxicity and cytotoxicity results were lower than the values used in the modulation. R. jimi glandular secretions demonstrated clinically relevant results regarding the modulation of the tested antimicrobials. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. Lethal inflammasome activation by a multi-drug resistant pathobiont upon antibiotic disruption of the microbiota

    Science.gov (United States)

    Ayres, Janelle S.; Trinidad, Norver J.; Vance, Russell E.

    2012-01-01

    The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host. However, the microbiota can also include potentially virulent species, termed pathobionts, which can cause disease when intestinal homeostasis is disrupted. The molecular mechanisms by which pathobionts cause disease remain poorly understood. Here we describe a sepsis-like disease that occurs upon gut injury in antibiotic-treated mice. Sepsis was associated with the systemic spread of a specific multidrug-resistant E. coli pathobiont that expanded dramatically in the microbiota of antibiotic-treated mice. Rapid sepsis-like death required a component of the innate immune system, the Naip5-Nlrc4 inflammasome. In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice. These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system. PMID:22522562

  14. Presence of Antibiotics in Shallow Groundwater in the Northern and Southwestern Regions of China.

    Science.gov (United States)

    Chen, Liang; Lang, Hang; Liu, Fei; Jin, Song; Yan, Tao

    2018-05-01

    Antibiotics are widely used, and there is a serious concern about its adverse impacts on the environment and human health. To our knowledge, prior to this work, there was no evidence of the potential presence of antibiotics in groundwater in China, despite populous speculations. This study reported the detection of 35 target antibiotics of 6 groups (chloramphenicois, lincosamides, marcrolides, quinolones, sulfonamides, and tetracyclines), in shallow groundwater samples collected in northern and southwestern China. Thirty-four of thirty-five target antibiotics were detected in the groundwater samples; 73 of 74 monitoring wells contained at least one antibiotic; and at least two antibiotics were detected in 72 of the 74 wells. Ofloxacin (1199.7 ng/L), lincomycin (860.7 ng/L), and norfloxacin (441.9 ng/L) as well as antibiotics with the highest detection frequency such as sulfapyridine (70%), norfloxacin (69%), and lincomycin (64%) were detected at elevated concentrations. The highest detection frequency and concentration of lincosamides were observed in those groundwater samples, but no clear distribution patterns were observed for the six antibiotic groups. Moreover, shallow groundwater in southwestern China seemed to contain most antibiotics, likely due to the high antibiotics discharge and frequent exchange of groundwater with surface matrices. The findings from this work suggest that groundwater in China has been widely contaminated by antibiotics, and presumably other pharmaceutical compounds that have not been investigated to date. © 2017, National Ground Water Association.

  15. Study on a new antifungal antibiotic, yimeimycin--isolation, structure elucidation and biological activities

    International Nuclear Information System (INIS)

    Shi Yuefeng; Sang Jinlong; Zhu Lihong; Li Xiaohui; Wu Jian

    2004-01-01

    Strain HA-8416, the producer of yimeimycin, was isolated from a soil sample collected in Hangzhou, Zhejiang province, China. Based on the investigation of morphological, cultural, physiological and biochemical characteristic as well as the cell wall chemical composition, strain HA8416 is extremely similar to Streptomyces hygrospinosus SF-104, and named Streptomyces hygrospinosus var tianmushanensis n. var. Sand et al. By means of spectroscopic analysis (UV, 1 H-NMR, DEPT CNMR and H-H COSY), yimeimycin was identified as a new antibiotic of the nucleoside family. Yimeimeycin appeared no activities against G + /G-bacteria, but was active against the fungi, Sphaerotheca cucurbitae, Pellicularia sasakii, Colletotrichum orbiculare, especially

  16. Antagonistic Activities of Purple Non-sulfur Bacterial Extracts Against Antibiotic Resistant Vibrio sp.

    Directory of Open Access Journals (Sweden)

    Chandrasekaran, R.

    2011-01-01

    Full Text Available Solvent extracts of native purple non-sulfur bacterial (PNSB isolates from the effluents of brackish shrimp culture ponds, near Nagapattinam coast (South India were evaluated for antibacterial activity by the disc diffusion method. Best results were shown by the chloroform extracts against oxytetracycline resistant Vibrio harveyi and Vibrio fischerii. Among the purple non-sulfur bacterial isolates, Rhodobacter sphaeroides, showed maximum antagonistic activity. The findings suggest that the antagonistic extracts from Rba. sphaeroides could be used as an effective antibiotic in controlling Vibrio spp., in aquaculture systems.

  17. Control of Citrus Huanglongbing via Trunk Injection of Plant Defense Activators and Antibiotics.

    Science.gov (United States)

    Hu, J; Jiang, J; Wang, N

    2018-02-01

    Citrus huanglongbing (HLB) or greening is a devastating disease of citrus worldwide and no effective control measure is currently available. Plant defense activators environmentally friendly compounds capable of inducing resistance against many plant pathogens. Earlier studies showed that foliar spray of plant defense inducers could slow down HLB disease progress. In this study, eight plant defense activators and three antibiotics were evaluated in three field trials for their effect to control HLB by trunk injection of young and mature sweet orange trees. Results showed that four trunk injections of several activators, including salicylic acid, oxalic acid, acibenzolar-S-methyl, and potassium phosphate, provided significant control of HLB by suppressing 'Candidatus Liberibacter asiaticus' titer and disease progress. Trunk injection of penicillin, streptomycin, and oxytetracycline hydrochloride resulted in excellent control of HLB. In general, antibiotics were more effective in reduction of 'Ca. L. asiaticus' titer and HLB symptom expressions than plant defense activators. These treatments also resulted in increased yield and better fruit quality. Injection of both salicylic acid and acibenzolar-S-methyl led to significant induction of pathogenesis-related (PR) genes PR-1 and PR-2 genes. Meanwhile, injection of either potassium phosphate or oxalic acid resulted in significant induction of PR-2 or PR-15 gene expression, respectively. These results suggested that HLB diseased trees remained inducible for systemic acquired resistance under field conditions. In summary, this study presents information regarding controlling HLB via trunk injection of plant defense activators and antibiotics, which helps citrus growers in decision making regarding developing an effective HLB management program.

  18. Antibiotic activity of the extract of Punica granatum Linn. over bovine strains of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Maria A. R. Silva

    Full Text Available Human and veterinary medicines have not been so well succeeded in order to achieving their goals concerning the treatment of infections for long term caused by Staphylococcus aureus linked to resistance development against antibiotic agents. The antibiotic activity of the Punica granatum Linn. fresh fruit pericarp extract was evaluated by the agar diffusion method on 38 S. aureus strains, isolated from apparently healthy lactating cows in farms situated in counties of the semi-arid region of the State of Paraíba, Brazil to determine the minimum inhibitory concentration (MIC. Twenty-two of the thirty-eight strains are penicillin-resistant (PRSA. The extract of P. granatum presented potential antibiotic action over all the assayed strains, forming 10 to 36 mm diameter inhibition zones. This paper's results claim the effectiveness of the extract of P. granatum as a potential antibacterial agent on S. aureus, and display the significance of evaluating new substances with antimicrobial potential, which can contribute to alternative therapeutics for veterinary and medicine.

  19. Isolation, Phylogenetic Analysis and Antibiotic Activity Screening of Red Sea Sponge-Associated Actinobacteria

    KAUST Repository

    Yang, Chen

    2013-06-01

    Infectious disease has always been and will continue to be a heavy burden on human society worldwide. Terrestrial actinobacteria, notable as a source of antibiotics, have been well investigated in the past. In constrast, marine actinobacteria, especially sponge-associated species, have received much less attention and isolates are sparse. With the aim of studying and discovering novel marine actinobacteria, 11 different species of sponges were collected from the Central Red Sea in Saudi Arabia and cultured with three different types of media. 16S rRNA gene-sequencing revealed that among all 75 isolated bacterial strains 13 belonged to the order actinomycetales. These 13 actinomycetes fall into four different families and can be assigned to six different genera. Antibiotic activity tests using disc diffusion assay were performed against Gram-positive bacteria (Bacillus sp.), Gram-negative bacteria (Escherichia coli), fungi (Fusarium sp.) and West Nile virus NS3 protease. Nine strains presented different level of bioactivity against these pathogens. These findings provide evidence that actinomycetes are presented in marine sponges and that they have the potential to be good candidates in the search for new effective antibiotic, antifungal, and antiviral compounds.

  20. Antimicrobial and enhancement of the antibiotic activity by phenolic compounds: Gallic acid, caffeic acid and pyrogallol.

    Science.gov (United States)

    Lima, Valéria N; Oliveira-Tintino, Cícera D M; Santos, Enaide S; Morais, Luís P; Tintino, Saulo R; Freitas, Thiago S; Geraldo, Yuri S; Pereira, Raimundo L S; Cruz, Rafael P; Menezes, Irwin R A; Coutinho, Henrique D M

    2016-10-01

    The indiscriminate use of antimicrobial drugs has increased the spectrum of exposure of these organisms. In our studies, these phenolic compounds were evaluated: gallic acid, caffeic acid and pyrogallol. The antibacterial, antifungal and modulatory of antibiotic activities of these compounds were assayed using microdilution method of Minimum Inhibitory Concentration (MIC) to bacteria and Minimum Fungicide Concentration (MFC) to fungi. The modulation was made by comparisons of the MIC and MFC of the compounds alone and combined with drugs against bacteria and fungi respectively, using a sub-inhibitory concentration of 128 μg/mL of substances (MIC/8). All substances not demonstrated clinically relevant antibacterial activity with a MIC above ≥1024 μg/mL. As a result, we observed that the caffeic acid presented a potentiating antibacterial effect over the 3 groups of bacteria studied. Pyrogallol showed a synergistic effect with two of the antibiotics tested, but only against Staphylococcus aureus. In general, caffeic acid was the substance that presented with the greatest number of antibiotics and with the greatest number of bacteria. In relation to the antifungal activity of all the compounds, the verified results were ≥1024 μg/mL, not demonstrating significant activity. Regarding potentiation of the effect of fluconazole, was observed synergistic effect only when assayed against Candida tropicalis, with all substances. Therefore, as can be seen, the compounds presented as substances that can be promising potentiating agents of antimicrobial drugs, even though they do not have direct antibacterial and antifungal action. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Syzygium jambos Displayed Antibacterial and Antibiotic-Modulating Activities against Resistant Phenotypes

    Directory of Open Access Journals (Sweden)

    Brice E. N. Wamba

    2018-01-01

    Full Text Available The present study was designed to evaluate the antibacterial activities of methanol extracts of bark and leaves of Syzygium jambos, as well as their synergistic effects with selected antibiotics against drug-resistant Gram-positive and Gram-negative bacteria. The crude extracts were subjected to qualitative phytochemical screening; broth microdilution method was used for antibacterial assays. Phytochemical studies indicate that leaves and bark extracts contained polyphenols, anthraquinones, tannins, and steroids. Extract of the leaves was active against all the 26 strains of Staphylococcus aureus and all the 21 strains of Gram-negative bacteria tested, within the minimum inhibitory concentration (MIC range of 32–512 μg/mL. The lowest MIC value of 32 μg/mL was obtained with extract of the leaves against Staphylococcus aureus MRSA9 strain. In Gram-negative bacteria, the lowest MIC value of 64 μg/mL was also obtained against Enterobacter aerogenes EA294 and Klebsiella pneumoniae K24 strains. Against S. aureus strains, antibiotic-modulating activity of extracts at MIC/2 towards more than 70% of the tested strains was obtained when leaves and bark extracts were tested in association with chloramphenicol (CHL. This was also the case when leaves extract was combined with CHL, kanamycin (KAN, tetracycline (TET, and erythromycin (ERY and when bark extract was combined with ciprofloxacin (CIP, TET, and ERY against Gram-negative bacteria. In conclusion, this study demonstrated that Syzygium jambos has antibacterial and antibiotic-modulating activities.

  2. Quantitative structure-activity relationship analysis to elucidate the clearance mechanisms of Tc-99m labeled quinolone antibiotics

    International Nuclear Information System (INIS)

    Salahinejad, M.; Mirshojaei, S.F.

    2016-01-01

    This study aims to establish molecular modeling methods for predicting the liver and kidney uptakes of Tc-99m labeled quinolone antibiotics. Some three-dimensional quantitative-activity relationships (3D-QSAR) models were developed using comparative molecular field analysis and grid-independent descriptors procedures. As a first report on 3D-QSAR modeling, the predicted liver and kidney uptakes for quinolone antibiotics were in good agreement with the experimental values. The obtained results confirm the importance of hydrophobic interactions, size and steric hindrance of antibiotic molecules in their liver uptakes, while the electrostatic interactions and hydrogen bonding ability have impressive effects on their kidney uptakes. (author)

  3. Antibacterial activities of selected Cameroonian spices and their synergistic effects with antibiotics against multidrug-resistant phenotypes

    Science.gov (United States)

    2011-01-01

    Background The emergence of multi-drug resistant (MDR) phenotypes is a major public health problem today in the treatment of bacterial infections. The present study was designed to evaluate the antibacterial activities of the methanol extracts of eleven Cameroonian spices on a panel of twenty nine Gram negative bacteria including MDR strains. Methods The phytochemical analysis of the extracts was carried out by standard tests meanwhile the liquid micro-broth dilution was used for all antimicrobial assays. Results Phytochemical analysis showed the presence of alkaloids, phenols and tannins in all plants extracts. The results of the antibacterial assays indicated that all tested extracts exert antibacterial activities, with the minimum inhibitory concentration (MIC) values varying from 32 to 1024 μg/ml. The extracts from Dichrostachys glomerata, Beilschmiedia cinnamomea, Aframomum citratum, Piper capense, Echinops giganteus, Fagara xanthoxyloïdes and Olax subscorpioïdea were the most active. In the presence of efflux pump inhibitor, PAßN, the activity of the extract from D. glomerata significantly increased on 69.2% of the tested MDR bacteria. At MIC/5, synergistic effects were noted with the extract of D. glomerata on 75% of the tested bacteria for chloramphenicol (CHL), tetracycline (TET) and norfloxacin (NOR). With B. cinnamomea synergy were observed on 62.5% of the studied MDR bacteria with CHL, cefepime (FEP), NOR and ciprofloxacin (CIP) and 75% with erythromycin (ERY). Conclusion The overall results provide information for the possible use of the studied extracts of the spices in the control of bacterial infections involving MDR phenotypes. PMID:22044718

  4. Chemical composition and antibacterial activities of Illicium verum against antibiotic-resistant pathogens.

    Science.gov (United States)

    Yang, Jyh-Ferng; Yang, Cheng-Hong; Chang, Hsueh-Wei; Yang, Cheng-San; Wang, Shao-Ming; Hsieh, Ming-Che; Chuang, Li-Yeh

    2010-10-01

    In recent years, human pathogenic microorganisms have developed multiple drug resistance and caused serious nosocomial infections. In this study, we identified four new antimicrobial compounds from the Chinese herbal medicine Illicium verum and assessed their antibacterial efficacies. The supercritical CO₂ and ethanol extracts of Illicium verum showed substantial antibacterial activity against 67 clinical drug-resistant isolates, including 27 Acinetobacter baumannii, 20 Pseudomonas aeruginosa, and 20 methicillin-resistant Staphylococcus aureus. The diethyl ether (EE) fraction obtained from partition extraction and supercritical CO₂ extracts revealed an antibacterial activity with a minimum inhibitory concentration value of 0.15-0.70 mg/mL and 0.11 mg/mL, respectively. The EE fraction of I. verum showed synergetic effects with some commercial antibiotics. The antimicrobial mechanism was investigated with killing curves and scanning electron microscopy observation. The chemical components of the extracts were analyzed by spectrophotometry; (E)-anethole, anisyl acetone, anisyl alcohol, and anisyl aldehyde exhibited antibacterial activity against different clinical isolates. These extracts from I. verum can be further developed into antibiotic medicines due to their proven antibacterial activity.

  5. Pathogen- and host-directed anti-inflammatory activities of macrolide antibiotics.

    Science.gov (United States)

    Steel, Helen C; Theron, Annette J; Cockeran, Riana; Anderson, Ronald; Feldman, Charles

    2012-01-01

    Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmful inflammatory responses during acute and chronic bacterial infection. These secondary anti-inflammatory activities of macrolides appear to be particularly effective in attenuating neutrophil-mediated inflammation. This, in turn, may contribute to the usefulness of these agents in the treatment of acute and chronic inflammatory disorders of both microbial and nonmicrobial origin, predominantly of the airways. This paper is focused on the various mechanisms of macrolide-mediated anti-inflammatory activity which target both microbial pathogens and the cells of the innate and adaptive immune systems, with emphasis on their clinical relevance.

  6. Fate of sulfonamide antibiotics in contact with activated sludge--sorption and biodegradation.

    Science.gov (United States)

    Yang, Sheng-Fu; Lin, Cheng-Fang; Wu, Chien-Ju; Ng, Kok-Kwang; Lin, Angela Yu-Chen; Hong, Pui-Kwan Andy

    2012-03-15

    The sorption and biodegradation of three sulfonamide antibiotics, namely sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamonomethoxine (SMM), in an activated sludge system were investigated. Experiments were carried out by contacting 100 μg/L of each sulfonamide compound individually with 2.56 g/L of MLSS at 25±0.5 °C, pH 7.0, and dissolved oxygen of 3.0±0.1 mg/L in a batch reactor over different periods of 2 d and 14 d. All sulfonamides were removed completely over 11-13 d. Sorptive equilibrium was established well within the first few hours, followed by a lag period of 1-3 days before biodegradation was to deplete the antibiotic compounds linearly in the ensuing 10 days. Apparent zeroth-order rate constants were obtained by regression analysis of measured aqueous concentration vs. time profiles to a kinetic model accounting for sorption and biodegradation; they were 8.1, 7.9, and 7.7 μg/L/d for SDM, SMX, and SMM, respectively, at activated sludge concentration of 2.56 g/L. The measured kinetics implied that with typical hydraulic retention time (e.g. 6 h) provided by WWTP the removal of sulfonamide compounds from the wastewater during the activated sludge process would approximate 2 μg/L. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Antimicrobial activity of nisin against the swine pathogen Streptococcus suis and its synergistic interaction with antibiotics.

    Science.gov (United States)

    Lebel, Geneviève; Piché, Fanny; Frenette, Michel; Gottschalk, Marcelo; Grenier, Daniel

    2013-12-01

    Streptococcus suis serotype 2 is known to cause severe infections in pigs, including meningitis, endocarditis and pneumonia. Furthermore, this bacterium is considered an emerging zoonotic agent. Recently, increased antibiotic resistance in S. suis has been reported worldwide. The objective of this study was to evaluate the potential of nisin, a bacteriocin of the lantibiotic class, as an antibacterial agent against the pathogen S. suis serotype 2. In addition, the synergistic activity of nisin in combination with conventional antibiotics was assessed. Using a plate assay, the nisin-producing strain Lactococcus lactis ATCC 11454 proved to be capable of inhibiting the growth of S. suis (n=18) belonging to either sequence type (ST)1, ST25, or ST28. In a microdilution broth assay, the minimum inhibitory concentration (MIC) of purified nisin ranged between 1.25 and 5 μg/mL while the minimum bactericidal concentration (MBC) was between 5 and 10 μg/mL toward S. suis. The use of a capsule-deficient mutant of S. suis indicated that the presence of this polysaccharidic structure has no marked impact on susceptibility to nisin. Following treatment of S. suis with nisin, transmission electron microscopy observations revealed lysis of bacteria resulting from breakdown of the cell membrane. A time-killing curve showed a rapid bactericidal activity of nisin. Lastly, synergistic effects of nisin were observed in combination with several antibiotics, including penicillin, amoxicillin, tetracycline, streptomycin and ceftiofur. This study brought clear evidence supporting the potential of nisin for the prevention and treatment of S. suis infections in pigs. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Potentiation of antibiotic activity of aminoglycosides by natural products from Cordia verbenacea DC.

    Science.gov (United States)

    Matias, Edinardo F F; Alves, Erivania F; Silva, Maria K N; Carvalho, Victoria R A; Medeiros, Cassio R; Santos, Francisco A V; Bitu, Vanessa C N; Souza, Celestina E S; Figueredo, Fernando G; Boligon, Aline A; Athayde, Margareth L; Costa, José G M; Coutinho, Henrique D M

    2016-06-01

    Medicinal plants are often the only therapeutic resource for many communities and ethnic groups. Cordia verbenacea DC., "Erva-baleeira," is one of the species of plants currently used to produce a phytotherapeutic product extracted from its leaves. The present study aimed to establish its chemical profile, antibacterial activity and resistance-modulating potential. The C. verbenacea extracts were prepared from fresh leaves using solvents as methanol and hexane. Ethyl Acetate was used for the preparation of the fraction. Phytochemical screening was carried out using HPLC-DAD for determination and quantification of the secondary metabolites present in the fractions. Antibacterial and resistance-modulation assays were performed to determine minimum inhibitory concentration (MIC) using a microdilution assay. The data were subjected to statistical analysis with two-way ANOVA and Bonferroni posttests. Results of phytochemical prospecting and HPLC analysis of the fractions were in agreement with the literature. The natural products presented moderate antibacterial activity when considering the clinical relevance of a MIC of 256 μg/mL against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and 512 μg/mL against P. aeruginosa. However, when the fractions were combined with antibiotics we observed a synergic effect, as natural products enhanced the antibacterial effect of aminoglycosides, significantly decreasing the MIC of antibiotics at 12.5%-98.4%. We believe that the data obtained from phytochemical analysis and from antibacterial and resistance modulation assays of C. verbenacea extracts new can open perspectives in the search for new alternatives for the treatment of bacterial infections and stimulate the renewed use of antibiotics with reduced effectiveness due to resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Antibiotic resistance pattern in uropathogens

    Directory of Open Access Journals (Sweden)

    Gupta V

    2002-01-01

    Full Text Available Uropathogenic strains from inpatient and outpatient departments were studied from April 1997 to March 1999 for their susceptibility profiles. The various isolates were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Acinetobacter baumanii and Enterococcus faecalis. Antibiotic susceptibility pattern of these isolates revealed that for outpatients, first generation cephalosporins, nitrofurantoin, norfloxacin/ciprofloxacin were effective for treatment of urinary tract infection but for inpatients, parenteral therapy with newer aminoglycosides and third generation cephalosporins need to be advocated as the organisms for nosocomial UTI exhibit a high degree of drug resistance. Trimethoprim and sulphamethoxazole combination was not found to be effective for the treatment of urinary tract infections as all the uropathogens from inpatients and outpatients showed high degree of resistance to co-trimoxazole. Culture and sensitivity of the isolates from urine samples should be done as a routine before advocating the therapy.

  10. Chemical composition and antibacterial activity of Lavandula coronopifolia essential oil against antibiotic-resistant bacteria.

    Science.gov (United States)

    Ait Said, L; Zahlane, K; Ghalbane, I; El Messoussi, S; Romane, A; Cavaleiro, C; Salgueiro, L

    2015-01-01

    The aim of this study was to analyse the composition of the essential oil (EO) of Lavandula coronopifolia from Morocco and to evaluate its in vitro antibacterial activity against antibiotic-resistant bacteria isolated from clinical infections. The antimicrobial activity was assessed by a broth micro-well dilution method using multiresistant clinical isolates of 11 pathogenic bacteria: Klebsiella pneumoniae subsp. pneumoniae, Klebsiella ornithinolytica, Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Providencia rettgeri, Citrobacter freundii, Hafnia alvei, Salmonella spp., Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus. The main compounds of the oil were carvacrol (48.9%), E-caryophyllene (10.8%) and caryophyllene oxide (7.7%). The oil showed activity against all tested strains with minimal inhibitory concentration (MIC) values ranging between 1% and 4%. For most of the strains, the MIC value was equivalent to the minimal bactericidal concentration value, indicating a clear bactericidal effect of L. coronopifolia EO.

  11. Biosynthetically Guided Structure-Activity Relationship Studies of Merochlorin A, an Antibiotic Marine Natural Product.

    Science.gov (United States)

    López-Pérez, Borja; Pepper, Henry P; Ma, Rong; Fawcett, Benjamin J; Pehere, Ashok D; Wei, Qi; Ji, Zengchun; Polyak, Steven W; Dai, Huanqin; Song, Fuhang; Abell, Andrew D; Zhang, Lixin; George, Jonathan H

    2017-12-07

    The onset of new multidrug-resistant strains of bacteria demands continuous development of antibacterial agents with new chemical scaffolds and mechanisms of action. We present the first structure-activity relationship (SAR) study of 16 derivatives of a structurally novel antibiotic merochlorin A that were designed using a biosynthetic blueprint. Our lead compounds are active against several Gram-positive bacteria such as Staphylococcus aureus (SA), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE) and Bacillus subtilis, inhibit intracellular growth of Mycobacterium bovis, and are relatively nontoxic to human cell lines. Furthermore, derivative 12 c {(±)-(3aR,4S,5R,10bS)-5-bromo-7,9-dimethoxy-4-methyl-4-(4-methylpent-3-en-1-yl)-2-(propan-2-ylidene)-1,2,3,3a,4,5-hexahydro-6H-5,10b-methanobenzo[e]azulene-6,11-dione} was found to inhibit the growth of Bacillus Calmette-Guérin (BCG)-infected cells at concentrations similar to rifampicin. These results outperform the natural product, underscoring the potential of merochlorin analogues as a new class of antibiotics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Antibiotic activity and synergistic effect of antimicrobial peptide against pathogens from a patient with gallstones

    International Nuclear Information System (INIS)

    Park, Yoonkyung; Park, Soon Nang; Park, Seong-Cheol; Park, Joon Yong; Park, Yong Ha; Hahm, Joon Soo; Hahm, Kyung-Soo

    2004-01-01

    HP (2-20) is a peptide derived from the N-terminus of Helicobacter pylori ribosomal protein L1 that has been shown to have antimicrobial activity against various species of bacteria. When we tested the effects of HP (2-20), we found that this peptide displayed strong activity against pathogens from a patient with gallstones, but it did not have hemolytic activity against human erythrocytes. We also found that HP (2-20) had potent activity against cefazolin sodium-resistant bacterial cell lines, and that HP (2-20) and cefazolin sodium had synergistic effects against cell lines resistant to the latter. To investigate the mechanism of action of HP (2-20), we performed fluorescence activated flow cytometry using pathogens from the patient with gallstones. As determined by propidium iodide (PI) staining, pathogenic bacteria treated with HP (2-20) showed higher fluorescence intensity than untreated cells, similar to melittin-treated cells, and that HP (2-20) acted in an energy- and salt-dependent manner. Scanning electron microscopy showed that HP (2-20) caused significant morphological alterations in the cell surface of pathogens from the patient with gallstones. By determining their 16S rDNA sequences, we found that both the pathogens from the patient with gallstones and the cefazolin sodium-resistant cell lines showed 100% homology with sequences from Pseudomonas aeruginosa. Taken together, these results suggest that HP (2-20) has antibiotic activity and that it may be used as a lead drug for the treatment of acquired pathogens from patients with gallstones and antibiotic-resistant cell lines

  13. Simultaneous electricity production and antibiotics removal by microbial fuel cells.

    Science.gov (United States)

    Zhou, Ying; Zhu, Nengwu; Guo, Wenying; Wang, Yun; Huang, Xixian; Wu, Pingxiao; Dang, Zhi; Zhang, Xiaoping; Xian, Jinchan

    2018-04-07

    The removal of antibiotics is crucial for improvement of water quality in animal wastewater treatment. In this paper, the performance of microbial fuel cell (MFC) in terms of degradation of typical antibiotics was investigated. Electricity was successfully produced by using sludge supernatant mixtures and synthesized animal wastewater as inoculation in MFC. Results demonstrated that the stable voltage, the maximum power density and internal resistance of anaerobic self-electrolysis (ASE) -112 and ASE-116 without antibiotics addition were 0.574 V, 5.78 W m -3 and 28.06 Ω, and 0.565 V, 5.82 W m -3 and 29.38 Ω, respectively. Moreover, when adding aureomycin, sulfadimidine, roxithromycin and norfloxacin into the reactors, the performance of MFC was inhibited (0.51 V-0.41 V), while the output voltage was improved with the decreased concentration of antibiotics. However, the removal efficiency of ammonia nitrogen (NH 3 -N) and total phosphorus (TP) were both obviously enhanced. Simultaneously, LC-MS analysis showed that the removal efficiency of aureomycin, roxithromycin and norfloxacin were all 100% and the removal efficiency of sulfadimidine also reached 99.9%. These results indicated that antibiotics displayed significantly inhibitions for electricity performance but improved the quality of water simultaneously. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. In vitro synergistic effects of fisetin and norfloxacin against aquatic isolates of Serratia marcescens.

    Science.gov (United States)

    Dong, Jing; Ruan, Jing; Xu, Ning; Yang, Yibin; Ai, Xiaohui

    2016-01-01

    Serratia marcescens is a common pathogenic bacterium that can cause infections in both humans and animals. It can cause a range of diseases, from slight wound infections to life-threatening bacteraemia and pneumonia. The emergence of antimicrobial resistance has limited the treatment of the diseases caused by the bacterium to a great extent. Consequently, there is an urgent need to develop novel antimicrobial strategies against this pathogen. Synergistic strategy is a new approach to treat the infections caused by drug-resistant bacteria. In this paper, we isolated and identified the first multi-resistant pathogenic Serratia marcescens strain from diseased soft-shelled turtles (Pelodiscus sinensis) in China. We then performed a checkerboard assay; the results showed that out of 10 tested natural products fisetin had synergistic effects against S. marcescens when combined with norfloxacin. The time-kill curve assay further confirmed the results of the checkerboard assay. We found that this novel synergistic effect could significantly reduce the dosage of norfloxacin against S. marcescens. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Enhancement of antibiotic activity by efflux inhibitors against multidrug resistant Mycobacterium tuberculosis clinical isolates from Brazil

    Directory of Open Access Journals (Sweden)

    Tatiane eCoelho

    2015-04-01

    Full Text Available Drug resistant tuberculosis continues to increase and new approaches for its treatment are necessary. The identification of M. tuberculosis clinical isolates presenting efflux as part of their resistant phenotype has a major impact in tuberculosis treatment. In this work, we used a checkerboard procedure combined with the tetrazolium microplate-based assay (TEMA to study single combinations between antituberculosis drugs and efflux inhibitors (EIs against multidrug resistant M. tuberculosis clinical isolates using the fully susceptible strain H37Rv as reference. Efflux activity was studied on a real-time basis by a fluorometric method that uses ethidium bromide as efflux substrate. Quantification of efflux pump genes mRNA transcriptional levels were performed by RT-qPCR. The fractional inhibitory concentrations (FIC indicated synergistic activity for the interactions between isoniazid, rifampicin, amikacin, ofloxacin, and ethidium bromide plus the EIs verapamil, thioridazine and chlorpromazine. The FICs ranged from 0.25, indicating a four-fold reduction on the MICs, to 0.015, 64-fold reduction. The detection of active efflux by real-time fluorometry showed that all strains presented intrinsic efflux activity that contributes to the overall resistance which can be inhibited in the presence of the EIs. The quantification of the mRNA levels of the most important efflux pump genes on these strains shows that they are intrinsically predisposed to expel toxic compounds as the exposure to subinhibitory concentrations of antibiotics were not necessary to increase the pump mRNA levels when compared with the non-exposed counterpart. The results obtained in this study confirm that the intrinsic efflux activity contributes to the overall resistance in multidrug resistant clinical isolates of M. tuberculosis and that the inhibition of efflux pumps by the EIs can enhance the clinical effect of antibiotics that are their substrates.

  16. Microbial colonization of biopolymeric thin films containing natural compounds and antibiotics fabricated by MAPLE

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, PO Box MG-36, Bucharest-Magurele (Romania); Surdu, A.V.; Grumezescu, A.M.; Oprea, A.E.; Trusca, R.; Vasile, O. [Faculty of Applied Chemistry and Materials Science, Department of Science and Engineering of Oxide Materials and Nanomaterials, Politehnica University of Bucharest, Polizu Street No. 1–7, 011061 Bucharest (Romania); Dorcioman, G.; Visan, A.; Socol, G.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, PO Box MG-36, Bucharest-Magurele (Romania); Mihaiescu, D. [Faculty of Applied Chemistry and Materials Science, Department of Organic Chemistry, Politehnica University of Bucharest, 1–7 Polizu Street, 011061 Bucharest (Romania); Enculescu, M. [National Institute of Materials Physics, PO Box MG-7, Bucharest-Magurele (Romania); Chifiriuc, M.C. [Microbiology Immunology Department, Faculty of Biology, Research Institute of the University of Bucharest—ICUB, Research Institute of the University of Bucharest, 77206 Bucharest (Romania); Boehm, R.D.; Narayan, R.J. [Biomedical Engineering, University of North Carolina, Chapel Hill, NC (United States); Chrisey, D.B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA (United States)

    2015-05-01

    Highlights: • We deposited thin composite quercetin/polyvinylpyrrolidone/antibiotic films with close resemblance to the starting/drop-cast composition by MAPLE. • Quercetin flavonoid shows an anti-biofilm activity comparable to that of the tested large-spectrum antibiotics (norfloxacin or cefuroxime), especially in case of 72 h biofilms. • These results could account for the possible use of quercetin as an alternative to antibiotics to combat the mature biofilms developed on different substrates. • MAPLE may be used to produce implantable medical devices that provide a relatively long term in vitro stability and resistance to the growth of microorganisms. - Abstract: Although a great number of antibiotics are currently available, they are often rendered ineffective by the ability of microbial strains to develop genetic resistance and to grow in biofilms. Since many antimicrobial agents poorly penetrate biofilms, biofilm-associated infections often require high concentrations of antimicrobial agents for effective treatment. Among the various strategies that may be used to inhibit microbial biofilms, one strategy that has generated significant interest involves the use of bioactive surfaces that are resistant to microbial colonization. In this respect, we used matrix assisted pulsed laser evaporation (MAPLE) involving a pulsed KrF* excimer laser source (λ = 248 nm, τ = 25 ns, ν = 10 Hz) to obtain thin composite biopolymeric films containing natural (flavonoid) or synthetic (antibiotic) compounds as bioactive substances. Chemical composition and film structures were investigated by Fourier transform infrared spectroscopy and X-ray diffraction. Films morphology was studied by scanning electron microscopy and transmission electron microscopy. The antimicrobial assay of the microbial biofilms formed on these films was assessed by the viable cell counts method. The flavonoid-containing thin films showed increased resistance to microbial colonization

  17. Microbial colonization of biopolymeric thin films containing natural compounds and antibiotics fabricated by MAPLE

    International Nuclear Information System (INIS)

    Cristescu, R.; Surdu, A.V.; Grumezescu, A.M.; Oprea, A.E.; Trusca, R.; Vasile, O.; Dorcioman, G.; Visan, A.; Socol, G.; Mihailescu, I.N.; Mihaiescu, D.; Enculescu, M.; Chifiriuc, M.C.; Boehm, R.D.; Narayan, R.J.; Chrisey, D.B.

    2015-01-01

    Highlights: • We deposited thin composite quercetin/polyvinylpyrrolidone/antibiotic films with close resemblance to the starting/drop-cast composition by MAPLE. • Quercetin flavonoid shows an anti-biofilm activity comparable to that of the tested large-spectrum antibiotics (norfloxacin or cefuroxime), especially in case of 72 h biofilms. • These results could account for the possible use of quercetin as an alternative to antibiotics to combat the mature biofilms developed on different substrates. • MAPLE may be used to produce implantable medical devices that provide a relatively long term in vitro stability and resistance to the growth of microorganisms. - Abstract: Although a great number of antibiotics are currently available, they are often rendered ineffective by the ability of microbial strains to develop genetic resistance and to grow in biofilms. Since many antimicrobial agents poorly penetrate biofilms, biofilm-associated infections often require high concentrations of antimicrobial agents for effective treatment. Among the various strategies that may be used to inhibit microbial biofilms, one strategy that has generated significant interest involves the use of bioactive surfaces that are resistant to microbial colonization. In this respect, we used matrix assisted pulsed laser evaporation (MAPLE) involving a pulsed KrF* excimer laser source (λ = 248 nm, τ = 25 ns, ν = 10 Hz) to obtain thin composite biopolymeric films containing natural (flavonoid) or synthetic (antibiotic) compounds as bioactive substances. Chemical composition and film structures were investigated by Fourier transform infrared spectroscopy and X-ray diffraction. Films morphology was studied by scanning electron microscopy and transmission electron microscopy. The antimicrobial assay of the microbial biofilms formed on these films was assessed by the viable cell counts method. The flavonoid-containing thin films showed increased resistance to microbial colonization

  18. Activation of Multiple Antibiotic Resistance in Uropathogenic Escherichia coli Strains by Aryloxoalcanoic Acid Compounds

    Science.gov (United States)

    Balagué, Claudia; Véscovi, Eleonora García

    2001-01-01

    Clofibric and ethacrynic acids are prototypical pharmacological agents administered in the treatment of hypertrigliceridemia and as a diuretic agent, respectively. They share with 2,4-dichlorophenoxyacetic acid (the widely used herbicide known as 2,4-D) a chlorinated phenoxy structural moiety. These aryloxoalcanoic agents (AOAs) are mainly excreted by the renal route as unaltered or conjugated active compounds. The relatedness of these agents at the structural level and their potential effect on therapeutically treated or occupationally exposed individuals who are simultaneously undergoing a bacterial urinary tract infection led us to analyze their action on uropathogenic, clinically isolated Escherichia coli strains. We found that exposure to these compounds increases the bacterial resistance to an ample variety of antibiotics in clinical isolates of both uropathogenic and nonpathogenic E. coli strains. We demonstrate that the AOAs induce an alteration of the bacterial outer membrane permeability properties by the repression of the major porin OmpF in a micF-dependent process. Furthermore, we establish that the antibiotic resistance phenotype is primarily due to the induction of the MarRAB regulatory system by the AOAs, while other regulatory pathways that also converge into micF modulation (OmpR/EnvZ, SoxRS, and Lrp) remained unaltered. The fact that AOAs give rise to uropathogenic strains with a diminished susceptibility to antimicrobials highlights the impact of frequently underestimated or ignored collateral effects of chemical agents. PMID:11353631

  19. Yaequinolones, new insecticidal antibiotics produced by Penicillium sp. FKI-2140. I. Taxonomy, fermentation, isolation and biological activity.

    Science.gov (United States)

    Uchida, Ryuji; Imasato, Rie; Yamaguchi, Yuichi; Masuma, Rokuro; Shiomi, Kazuro; Tomoda, Hiroshi; Omura, Satoshi

    2006-10-01

    New nine insecticidal antibiotics designated yaequinolones were isolated from the culture broth of the fungal strain Penicillium sp. FKI-2140 by solvent extraction, centrifugal partition chromatography and HPLC. Yaequinolones showed growth inhibitory activity against brine shrimp (Artemia salina). Among them, yaequinolone F has the most potent activity with MIC value of 0.19 microg/ml.

  20. Characterization of Antibiotics and Antibiotic Resistance Genes on an Ecological Farm System

    Directory of Open Access Journals (Sweden)

    Songhe Zhang

    2015-01-01

    Full Text Available There is a growing concern worldwide about the prevalence of antibiotics and antibiotic resistance genes (ARGs on the farm. In this study, we investigated the distribution of seven antibiotics and ten ARGs in fresh and dried pig feces, in biogas slurry, and in grape-planting soil from an ecological farm. Antibiotics including sulfamethazine, norfloxacin, ofloxacin, tetracycline, oxytetracycline, and chlortetracycline were detected in these samples (except for sulfamethoxazole in dried feces. In general, antibiotics levels in samples were in the sequence: biogas slurry > fresh feces > soil or dried feces. Results of ecological risk assessments revealed that among the seven antibiotics chlortetracycline showed the highest ecological risk. Among the ten ARGs, sulI and tetO were the most prevalent on this ecological farm. There were positive correlations between certain ARGs and the corresponding antibiotics on this ecological farm. Therefore, continuous monitoring of antibiotics and their corresponding ARGs should be conducted in the agroecosystem near the concentrated animal farming operation systems.

  1. Assessing the antibiotic susceptibility of freshwater cyanobacteria spp.

    Directory of Open Access Journals (Sweden)

    Elsa eDias

    2015-08-01

    Full Text Available Freshwater is a vehicle for the emergence and dissemination of antibiotic resistance. Cyanobacteria are ubiquitous in freshwater, where they are exposed to antibiotics and resistant organisms, but their role on water resistome was never evaluated. Data concerning the effects of antibiotics on cyanobacteria, obtained by distinct methodologies, is often contradictory. This emphasizes the importance of developing procedures to understand the trends of antibiotic susceptibility in cyanobacteria. In this study we aimed to evaluate the susceptibility of four cyanobacterial isolates from different genera (Microcystis aeruginosa, Aphanizomenon gracile, Chrisosporum bergii, Planktothix agradhii, and among them nine isolates from the same specie (M. aeruginosa to distinct antibiotics (amoxicillin, ceftazidime, ceftriaxone, kanamycine, gentamicine, tetracycline, trimethoprim, nalidixic acid, norfloxacin. We used a method adapted from the bacteria standard broth microdilution. Cyanobacteria were exposed to serial dilution of each antibiotic (0.0015-1.6 mg/L in Z8 medium (20 ± 1 ºC; 14/10 h L/D cycle; light intensity 16 ± 4 µEm-2 s-1. Cell growth was followed overtime (OD450nm/microscopic examination and the minimum inhibitory concentrations (MICs were calculated for each antibiotic/isolate. We found that -lactams exhibited the lower MICs, aminoglycosides, tetracycline and norfloxacine presented intermediate MICs; none of the isolates were susceptible to trimethoprim and nalidixic acid. The reduced susceptibility of all tested cyanobacteria to some antibiotics suggests that they might be naturally non-susceptible to these compounds, or that that they might became non-susceptible due to antibiotic contamination pressure, or to the transfer of genes from resistant bacteria present in the environment.

  2. Antibiotic discovery throughout the Small World Initiative: A molecular strategy to identify biosynthetic gene clusters involved in antagonistic activity.

    Science.gov (United States)

    Davis, Elizabeth; Sloan, Tyler; Aurelius, Krista; Barbour, Angela; Bodey, Elijah; Clark, Brigette; Dennis, Celeste; Drown, Rachel; Fleming, Megan; Humbert, Allison; Glasgo, Elizabeth; Kerns, Trent; Lingro, Kelly; McMillin, MacKenzie; Meyer, Aaron; Pope, Breanna; Stalevicz, April; Steffen, Brittney; Steindl, Austin; Williams, Carolyn; Wimberley, Carmen; Zenas, Robert; Butela, Kristen; Wildschutte, Hans

    2017-06-01

    The emergence of bacterial pathogens resistant to all known antibiotics is a global health crisis. Adding to this problem is that major pharmaceutical companies have shifted away from antibiotic discovery due to low profitability. As a result, the pipeline of new antibiotics is essentially dry and many bacteria now resist the effects of most commonly used drugs. To address this global health concern, citizen science through the Small World Initiative (SWI) was formed in 2012. As part of SWI, students isolate bacteria from their local environments, characterize the strains, and assay for antibiotic production. During the 2015 fall semester at Bowling Green State University, students isolated 77 soil-derived bacteria and genetically characterized strains using the 16S rRNA gene, identified strains exhibiting antagonistic activity, and performed an expanded SWI workflow using transposon mutagenesis to identify a biosynthetic gene cluster involved in toxigenic compound production. We identified one mutant with loss of antagonistic activity and through subsequent whole-genome sequencing and linker-mediated PCR identified a 24.9 kb biosynthetic gene locus likely involved in inhibitory activity in that mutant. Further assessment against human pathogens demonstrated the inhibition of Bacillus cereus, Listeria monocytogenes, and methicillin-resistant Staphylococcus aureus in the presence of this compound, thus supporting our molecular strategy as an effective research pipeline for SWI antibiotic discovery and genetic characterization. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  3. Selective entrapment of the cationic form of norfloxacin within anionic sodium dodecyl sulfate micelles at physiological pH and its effect on the drug photodecomposition.

    Science.gov (United States)

    Sortino, Salvatore

    2006-01-01

    The binding of the photosensitizing fluoroquinolone (FQ) antibiotic norfloxacin (NX) to sodium dodecyl sulfate (SDS) micelles and the photoreactivity of the NX/SDS complex under physiological pH conditions are investigated by means of absorption and emission spectroscopy, steady-state and laser flash photolysis. It is shown that the photolabile zwitterionic form of NX, which is dominant at physiological pH, is not the most abundant species in the presence of SDS micelles. This medium exhibits a high preference for the cationic form of the drug, which is selectively and successfully entrapped within the micellar cage (K(ass) = 6 x 10(4) M(-1) +/- 3000), becoming the largely dominant species at neutral pH. The effect of this trapping is drastically reflected on both efficiency and nature of the drug photodecomposition. It is observed that the photostability of NX incorporated in the micellar pseudophase increases of more than one order of magnitude if compared to that of the "free" drug. Furthermore, the radical photodecomposition mechanism occurring in phosphate buffered solution is suppressed by the micellar medium and the low photodegradation observed seems to take place preferentially through an ionic pathway. Hopefully, the results presented herein may contribute to a better understanding of the bio-distribution of NX in biological systems and provide helpful and stimulating information in order to get the control of FQ photoreactivity under physiological pH conditions.

  4. Differential trypanocidal activity of novel macrolide antibiotics; correlation to genetic lineage.

    Science.gov (United States)

    Aquilino, Carolina; Gonzalez Rubio, Maria Luisa; Seco, Elena Maria; Escudero, Leticia; Corvo, Laura; Soto, Manuel; Fresno, Manuel; Malpartida, Francisco; Bonay, Pedro

    2012-01-01

    Here we report the systematic study of the anti-trypanocidal activity of some new products derived from S. diastatus on 14 different T. cruzi strains spanning the six genetic lineages of T. cruzi. As the traditional growth inhibition curves giving similar IC(50) showed great differences on antibiotic and lineage tested, we decided to preserve the wealth of information derived from each inhibition curve and used an algorithm related to potency of the drugs, combined in a matrix data set used to generate a cluster tree. The cluster thus generated based just on drug susceptibility data closely resembles the phylogenies of the lineages derived from genetic data and provides a novel approach to correlate genetic data with phenotypes related to pathogenesis of Chagas disease. Furthermore we provide clues on the drugs mechanism of action.

  5. Differential trypanocidal activity of novel macrolide antibiotics; correlation to genetic lineage.

    Directory of Open Access Journals (Sweden)

    Carolina Aquilino

    Full Text Available Here we report the systematic study of the anti-trypanocidal activity of some new products derived from S. diastatus on 14 different T. cruzi strains spanning the six genetic lineages of T. cruzi. As the traditional growth inhibition curves giving similar IC(50 showed great differences on antibiotic and lineage tested, we decided to preserve the wealth of information derived from each inhibition curve and used an algorithm related to potency of the drugs, combined in a matrix data set used to generate a cluster tree. The cluster thus generated based just on drug susceptibility data closely resembles the phylogenies of the lineages derived from genetic data and provides a novel approach to correlate genetic data with phenotypes related to pathogenesis of Chagas disease. Furthermore we provide clues on the drugs mechanism of action.

  6. Antibiotic stress-induced modulation of the endoribonucleolytic activity of RNase III and RNase G confers resistance to aminoglycoside antibiotics in Escherichia coli.

    Science.gov (United States)

    Song, Wooseok; Kim, Yong-Hak; Sim, Se-Hoon; Hwang, Soonhye; Lee, Jung-Hyun; Lee, Younghoon; Bae, Jeehyeon; Hwang, Jihwan; Lee, Kangseok

    2014-04-01

    Here, we report a resistance mechanism that is induced through the modulation of 16S ribosomal RNA (rRNA) processing on the exposure of Escherichia coli cells to aminoglycoside antibiotics. We observed decreased expression levels of RNase G associated with increased RNase III activity on rng mRNA in a subgroup of E. coli isolates that transiently acquired resistance to low levels of kanamycin or streptomycin. Analyses of 16S rRNA from the aminoglycoside-resistant E. coli cells, in addition to mutagenesis studies, demonstrated that the accumulation of 16S rRNA precursors containing 3-8 extra nucleotides at the 5' terminus, which results from incomplete processing by RNase G, is responsible for the observed aminoglycoside resistance. Chemical protection, mass spectrometry analysis and cell-free translation assays revealed that the ribosomes from rng-deleted E. coli have decreased binding capacity for, and diminished sensitivity to, streptomycin and neomycin, compared with wild-type cells. It was observed that the deletion of rng had similar effects in Salmonella enterica serovar Typhimurium strain SL1344. Our findings suggest that modulation of the endoribonucleolytic activity of RNase III and RNase G constitutes a previously uncharacterized regulatory pathway for adaptive resistance in E. coli and related gram-negative bacteria to aminoglycoside antibiotics.

  7. Escape from Lethal Bacterial Competition through Coupled Activation of Antibiotic Resistance and a Mobilized Subpopulation

    Science.gov (United States)

    Stubbendieck, Reed M.; Straight, Paul D.

    2015-01-01

    Bacteria have diverse mechanisms for competition that include biosynthesis of extracellular enzymes and antibiotic metabolites, as well as changes in community physiology, such as biofilm formation or motility. Considered collectively, networks of competitive functions for any organism determine success or failure in competition. How bacteria integrate different mechanisms to optimize competitive fitness is not well studied. Here we study a model competitive interaction between two soil bacteria: Bacillus subtilis and Streptomyces sp. Mg1 (S. Mg1). On an agar surface, colonies of B. subtilis suffer cellular lysis and progressive degradation caused by S. Mg1 cultured at a distance. We identify the lytic and degradative activity (LDA) as linearmycins, which are produced by S. Mg1 and are sufficient to cause lysis of B. subtilis. We obtained B. subtilis mutants spontaneously resistant to LDA (LDAR) that have visibly distinctive morphology and spread across the agar surface. Every LDAR mutant identified had a missense mutation in yfiJK, which encodes a previously uncharacterized two-component signaling system. We confirmed that gain-of-function alleles in yfiJK cause a combination of LDAR, changes in colony morphology, and motility. Downstream of yfiJK are the yfiLMN genes, which encode an ATP-binding cassette transporter. We show that yfiLMN genes are necessary for LDA resistance. The developmental phenotypes of LDAR mutants are genetically separable from LDA resistance, suggesting that the two competitive functions are distinct, but regulated by a single two-component system. Our findings suggest that a subpopulation of B. subtilis activate an array of defensive responses to counter lytic stress imposed by competition. Coordinated regulation of development and antibiotic resistance is a streamlined mechanism to promote competitive fitness of bacteria. PMID:26647299

  8. Photocatalytic Role of Zinc Oxide Nanoparticles on Synthetic Activated Carbon to Remove Antibiotic from Aquatic Environment

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    Mohammad Reza Samarghandi

    2017-10-01

    Full Text Available Background & Aims of the Study: The presence of antibiotics in the environment, especially in aquatic environments is a major concern for health and the environment. The advanced oxidation process due to the ease of use, economical advantages and high performance have attracted a lot of attention. The purpose of this study was Evaluating of the photocatalytic role of zinc oxide on synthetic activated carbon to remove antibiotic from aquatic environment. Materials & Methods: This experimental study was done in batch reactor that has a 1 L volume. In this study effect of parameters such as initial pH (3-9, initial concentration of cefazolin (20-200 mg/L, modified photocatalyst concentration (20-100 mg/L and reaction time (10-60 min was investigated. In this study a low-pressure mercury lamp with the power of 55 watts in stainless case has been used. The cefazolin concentrations in different steps were measured using UV-Vis spectrophotometer in Wavelength of 262 nm. Results: The results showed that the highest removal efficiency (96% of cefazolin was at the pH=3, 0.1 mg/L of modified photocatalyst, retention time of 60 min and cefazolin concentrations of 100 mg/L. In the case of changing any of the above mentioned values, process efficiency was decreased. Conclusion: The results showed that the photocatalytic process of zinc oxide nanoparticles on synthetic activated carbon can be used as an advanced oxidation process to effectively remove pollutants like cefazolin and other similar pollutants.

  9. Metagenomic profiles of antibiotic resistance genes (ARGs) between human impacted estuary and deep ocean sediments.

    Science.gov (United States)

    Chen, Baowei; Yang, Ying; Liang, Ximei; Yu, Ke; Zhang, Tong; Li, Xiangdong

    2013-11-19

    Knowledge of the origins and dissemination of antibiotic resistance genes (ARGs) is essential for understanding modern resistomes in the environment. The mechanisms of the dissemination of ARGs can be revealed through comparative studies on the metagenomic profiling of ARGs between relatively pristine and human-impacted environments. The deep ocean bed of the South China Sea (SCS) is considered to be largely devoid of anthropogenic impacts, while the Pearl River Estuary (PRE) in south China has been highly impacted by intensive human activities. Commonly used antibiotics (sulfamethazine, norfloxacin, ofloxacin, tetracycline, and erythromycin) have been detected through chemical analysis in the PRE sediments, but not in the SCS sediments. In the relatively pristine SCS sediments, the most prevalent and abundant ARGs are those related to resistance to macrolides and polypeptides, with efflux pumps as the predominant mechanism. In the contaminated PRE sediments, the typical ARG profiles suggest a prevailing resistance to antibiotics commonly used in human health and animal farming (including sulfonamides, fluoroquinolones, and aminoglycosides), and higher diversity in both genotype and resistance mechanism than those in the SCS. In particular, antibiotic inactivation significantly contributed to the resistance to aminoglycosides, β-lactams, and macrolides observed in the PRE sediments. There was a significant correlation in the levels of abundance of ARGs and those of mobile genetic elements (including integrons and plasmids), which serve as carriers in the dissemination of ARGs in the aquatic environment. The metagenomic results from the current study support the view that ARGs naturally originate in pristine environments, while human activities accelerate the dissemination of ARGs so that microbes would be able to tolerate selective environmental stress in response to anthropogenic impacts.

  10. Antibiotics and Antibiotic Resistance

    Science.gov (United States)

    ... all that ails you. Antibiotics, also known as antimicrobial drugs, are drugs that fight infections caused by bacteria. ... Information for Consumers and Health Professionals Information by drug class Antimicrobial Resistance Animal and Veterinary Related Resources Further information ...

  11. In-vitro activity of flomoxef, a new oxacephem group antibiotic, against Nocardia in comparison with other cephalosporins.

    Science.gov (United States)

    Yazawa, K; Mikami, Y; Uno, J; Otozai, K; Arai, T

    1989-12-01

    The susceptibility of 113 strains of pathogenic Nocardia, N. asteroides, N. farcinica, N. nova, N. brasiliensis and N. otitidiscaviarum to a new oxacephem antibiotic flomoxef was determined by an agar dilution method in comparison with those of 13 other cephalosporins. Flomoxef was two to 50 times more active against these pathogenic Nocardia than other cephalopsorins tested. However, there were differences in susceptibility to this antibiotic among these Nocardia strains. N. asteroides was the most sensitive species, followed by N. farcinica and N. nova. N. brasiliensis was moderately sensitive and N. otitidiscaviarum was resistant.

  12. The synergistic activity of antibiotics combined with eight traditional Chinese medicines against two different strains of Staphylococcus aureus.

    Science.gov (United States)

    Yang, Zai-Chang; Wang, Bo-Chu; Yang, Xiao-Sheng; Wang, Qiang; Ran, Liang

    2005-03-25

    The ethanolic extracts of eight traditional Chinese medicines and four antibiotics were investigated for their combined effects on the resistance of Staphylococcus aureus (S. aureus) in vitro. Methicillin resistant S. aureus, which was isolated from patient and a standard strain, were used. Our results showed that there are differences in the effects of many combinations used on the standard strain and resistant strain of S. aureus. The ethanolic extracts of Isatis tinctoria, Scutellaria baicalensis and Rheum palmatum can improve the antimicrobial activity of four antibiotics we used.

  13. Antibacterial activity of selected medicinal plants against multiple antibiotic resistant uropathogens: a study from Kolli Hills, Tamil Nadu, India.

    Science.gov (United States)

    Narayanan, A S; Raja, S S S; Ponmurugan, K; Kandekar, S C; Natarajaseenivasan, K; Maripandi, A; Mandeel, Q A

    2011-09-01

    The increasing incidence of antibiotic resistance among bacterial pathogens necessitates medicinal plants as an alternate therapy in restricting the resistant infectious organisms. In this primitive study, the antibiotic resistance of organisms isolated from urinary tract infected patients was evaluated using the National Committee for Clinical Laboratory Standards (NCCLS) method and Multiple Antibiotic Resistance (MAR) index values, and the MAR values was also calculated for plant extracts. The 10 common medicinal plants collected from Kolli hills, Namakkal, south India were extracted using the chloroform, methanol, acetone, ethanol and saponification procedure. The efficacy of the extracts on the uropathogens was tested by agar disc diffusion method in order to analyse the inhibitory activity of plant extract on the organisms. Azadiracta indica A. Juss., Tinospora cordifolia (Wild.) and Euphorbia hirta Linn. exhibited high inhibitory activity against most of the 11 tested organisms followed by Cassia javanica Linn. and Phyllanthus niruri Linn. The maximum zone size of 46.3 mm was exhibited by methanol extract of P. niruri Linn. against Pseudomonas aeruginosa. Asparagus racemosus Willd. and Eupatorium triplinerve Vahl had the least activity against resistant pathogens. Saponified lipids of most of the plants exhibited maximum antibacterial activity. Among the tested organisms, P. aeruginosa and Staphylococcus epidermidis were the most susceptible and Serratia marcescens, Enterobacter cloaceae, Citrobacter koseri, and Citrobacter freundii were the least inhibited by most of the extracts of medicinal plants. It is concluded that revised antibiotic policies and more importantly the development of herbal medicine as an alternative may be incorporated in urological practice.

  14. Vancomycin analogues containing monosaccharides exhibit improved antibiotic activity: a combined one-pot enzymatic glycosylation and chemical diversification strategy.

    Science.gov (United States)

    Thayer, Desiree A; Wong, Chi-Huey

    2006-09-18

    Many natural products contain carbohydrate moieties that contribute to their biological activity. Manipulation of the carbohydrate domain of natural products through multiple glycosylations to identify new derivatives with novel biological activities has been a difficult and impractical process. We report a practical one-pot enzymatic approach with regeneration of cosubstrates to synthesize analogues of vancomycin that contain an N-alkyl glucosamine, which exhibited marked improvement in antibiotic activity against a vancomycin-resistant strain of Enterococcus.

  15. Fate of antibiotics in activated sludge followed by ultrafiltration (CAS-UF) and in a membrane bioreactor (MBR).

    Science.gov (United States)

    Sahar, Eyal; Messalem, Rami; Cikurel, Haim; Aharoni, Avi; Brenner, Asher; Godehardt, Manuel; Jekel, Martin; Ernst, Mathias

    2011-10-15

    The fates of several macrolide, sulphonamide, and trimethoprim antibiotics contained in the raw sewage of the Tel-Aviv wastewater treatment plant (WWTP) were investigated after the sewage was treated using either a full-scale conventional activated sludge (CAS) system coupled with a subsequent ultrafiltration (UF) step or a pilot membrane bioreactor (MBR) system. Antibiotics removal in the MBR system, once it achieved stable operation, was 15-42% higher than that of the CAS system. This advantage was reduced to a maximum of 20% when a UF was added to the CAS. It was hypothesized that the contribution of membrane separation (in both systems) to antibiotics removal was due either to sorption to biomass (rather than improvement in biodegradation) or to enmeshment in the membrane biofilm (since UF membrane pores are significantly larger than the contaminant molecules). Batch experiments with MBR biomass showed a markedly high potential for sorption of the tested antibiotics onto the biomass. Moreover, methanol extraction of MBR biomass released significant amounts of sorbed antibiotics. This finding implies that more attention must be devoted to the management of excess sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Antimicrobial Activity of Piper gaudichaudianum Kuntze and Its Synergism with Different Antibiotics

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    Benedito Prado Dias Filho

    2011-12-01

    Full Text Available One of the oldest forms of medical practice is the use of plants for the treatment and prevention of diseases that affect humans. We have studied the antimicrobial activity and synergism of Piper gaudichaudianum Kuntze with different antibiotics. The crude extract from the leaves of P. gaudichaudianum was submitted to chromatographic separation, resulting in five fractions. Fraction F3 contained a chromone (2,2-dimethyl-6-carboxycroman-4-one, and fraction F2 contained isomers that are prenylated derivatives of benzoic acid [4-hydroxy-(3',7'-dimethyl-1'-oxo-octa-E-2'-6'-dienylbenzoic acid and 4-hydroxy-(3',7'-dimethyl-1'-oxo-octa-2'-Z-6'-dienyl benzoic acid]. The chemical structures of both compounds were determined by analysis of 1H-NMR, 13C-NMR, COZY, DEPT, HMQC, and HMBC spectral data, and by comparison with data in the literature. The crude extract, fraction F2, and fraction F3 showed good activity against Staphylococcus aureus, Bacillus subtilis, and Candida tropicalis. The two benzoic acid derivatives only showed activity against S. aureus and B. subtilis. The bioauthographic analysis showed an inhibition zone only in fraction F2. Fractions F2 and F3 showed synergism in combination with ceftriaxone, tetracycline, and vancomycin. Morphological changes in form and structure were found by scanning electron microscopy in S. aureus treated with the combination of fraction F2 with vancomycin.

  17. Human Bile Reduces Antimicrobial Activity of Selected Antibiotics against Enterococcus faecalis and Escherichia coli In Vitro.

    Science.gov (United States)

    Wulkersdorfer, Beatrix; Jaros, David; Eberl, Sabine; Poschner, Stefan; Jäger, Walter; Cosentini, Enrico; Zeitlinger, Markus; Schwameis, Richard

    2017-08-01

    It has been known from previous studies that body fluids, such as cerebrospinal fluid, lung surfactant, and urine, have a strong impact on the bacterial killing of many anti-infective agents. However, the influence of human bile on the antimicrobial activity of antibiotics is widely unknown. Human bile was obtained and pooled from 11 patients undergoing cholecystectomy. After sterilization of the bile fluid by gamma irradiation, its effect on bacterial killing was investigated for linezolid (LZD) and tigecycline (TGC) against Enterococcus faecalis ATCC 29212. Further, ciprofloxacin (CIP), meropenem (MEM), and TGC were tested against Escherichia coli ATCC 25922. Time-kill curves were performed in pooled human bile and Mueller-Hinton broth (MHB) over 24 h. Bacterial counts (in CFU per milliliter after 24 h) of bile growth controls were approximately equal to MHB growth controls for E. coli and approximately 2-fold greater for E. faecalis , indicating a promotion of bacterial growth by bile for the latter strain. Bile reduced the antimicrobial activity of CIP, MEM, and TGC against E. coli as well as the activity of LZD and TGC against E. faecalis This effect was strongest for TGC against the two strains. Degradation of TGC in bile was identified as the most likely explanation. These findings may have important implications for the treatment of bacterial infections of the gallbladder and biliary tract and should be explored in more detail. Copyright © 2017 American Society for Microbiology.

  18. On the Enhanced Antibacterial Activity of Antibiotics Mixed with Gold Nanoparticles

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    Shantrokha AN

    2009-01-01

    Full Text Available Abstract The bacterial action of gentamicin and that of a mixture of gentamicin and 15-nm colloidal-gold particles onEscherichia coliK12 was examined by the agar-well-diffusion method, enumeration of colony-forming units, and turbidimetry. Addition of gentamicin to colloidal gold changed the gold color and extinction spectrum. Within the experimental errors, there were no significant differences in antibacterial activity between pure gentamicin and its mixture with gold nanoparticles (NPs. Atomic absorption spectroscopy showed that upon application of the gentamicin-particle mixture, there were no gold NPs in the zone of bacterial-growth suppression in agar. Yet, free NPs diffused into the agar. These facts are in conflict with the earlier findings indicating an enhancement of the bacterial activity of similar gentamicin–gold nanoparticle mixtures. The possible causes for these discrepancies are discussed, and the suggestion is made that a necessary condition for enhancement of antibacterial activity is the preparation of stable conjugates of NPs coated with the antibiotic molecules.

  19. Examination of antimicrobial activity of selected non-antibiotic medicinal preparations.

    Science.gov (United States)

    Kruszewska, Hanna; Zareba, Tomasz; Tyski, Stefan

    2012-01-01

    The aim of this study was to detect and characterize the antimicrobial activity of non-antibiotic drugs, selected from the pharmaceutical products analyzed during the state control performed in National Medicines Institute, Warszawa, Poland. In 2010, over 90 pharmaceutical preparations have been randomly chosen from different groups of drugs. The surveillance study was performed on standard ATCC microbial strains used for drug control: S. aureus, E. coli, P. aeruginosa and C. albicans. It was shown that the drugs listed below inhibited growth of at least one of the examined strains: Arketis 20 mg tab. (paroxetine), Buvasodil 150 mg tab. (buflomedile), Halidor 100 mg tab. (bencyclane), Hydroxyzinum espefa 25 mg tab. (hydroxyzine), Norifaz 35 mg tab. (risedronate), Strattera 60 mg cap. (atomoxetine), Tamiflu 75 mg tab. (oseltamivir), Valpro-ratiopharm Chrono 300 mg tab. with longer dissolution (valproate), Vetminth oral paste 24 g+3 g/100 mL (niclozamide, oxybendazol). Strattera cap. showed broad activity spectrum. It inhibited growth of all examined strains (MIC of active substance -- atomoxetine ranged between 2.6-13 mg/mL).

  20. Influence of a macrolide antibiotic, roxithromycin, on mast cell growth and activation in vitro

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    Toshikazu Shimane

    2001-01-01

    Full Text Available Background: Long-term administration of macrolide antibiotics is recognized to be able to favorably modify the clinical condition of inflammatory diseases, such as diffuse panbronchiolitis and cystic fibrosis. However, the precise mechanisms by which macrolide antibiotics could improve clinical conditions of the patients are not well understood.

  1. Real-time detection of antibiotic activity by measuring nanometer-scale bacterial deformation

    Science.gov (United States)

    Iriya, Rafael; Syal, Karan; Jing, Wenwen; Mo, Manni; Yu, Hui; Haydel, Shelley E.; Wang, Shaopeng; Tao, Nongjian

    2017-12-01

    Diagnosing antibiotic-resistant bacteria currently requires sensitive detection of phenotypic changes associated with antibiotic action on bacteria. Here, we present an optical imaging-based approach to quantify bacterial membrane deformation as a phenotypic feature in real-time with a nanometer scale (˜9 nm) detection limit. Using this approach, we found two types of antibiotic-induced membrane deformations in different bacterial strains: polymyxin B induced relatively uniform spatial deformation of Escherichia coli O157:H7 cells leading to change in cellular volume and ampicillin-induced localized spatial deformation leading to the formation of bulges or protrusions on uropathogenic E. coli CFT073 cells. We anticipate that the approach will contribute to understanding of antibiotic phenotypic effects on bacteria with a potential for applications in rapid antibiotic susceptibility testing.

  2. Alterations in the transcriptome and antibiotic susceptibility of Staphylococcus aureus grown in the presence of diclofenac

    Science.gov (United States)

    2011-01-01

    Background Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) which has been shown to increase the susceptibility of various bacteria to antimicrobials and demonstrated to have broad antimicrobial activity. This study describes transcriptome alterations in S. aureus strain COL grown with diclofenac and characterizes the effects of this NSAID on antibiotic susceptibility in laboratory, clinical and diclofenac reduced-susceptibility (DcRS) S. aureus strains. Methods Transcriptional alterations in response to growth with diclofenac were measured using S. aureus gene expression microarrays and quantitative real-time PCR. Antimicrobial susceptibility was determined by agar diffusion MICs and gradient plate analysis. Ciprofloxacin accumulation was measured by fluorescence spectrophotometry. Results Growth of S. aureus strain COL with 80 μg/ml (0.2 × MIC) of diclofenac resulted in the significant alteration by ≥2-fold of 458 genes. These represented genes encoding proteins for transport and binding, protein and DNA synthesis, and the cell envelope. Notable alterations included the strong down-regulation of antimicrobial efflux pumps including mepRAB and a putative emrAB/qacA-family pump. Diclofenac up-regulated sigB (σB), encoding an alternative sigma factor which has been shown to be important for antimicrobial resistance. Staphylococcus aureus microarray metadatabase (SAMMD) analysis further revealed that 46% of genes differentially-expressed with diclofenac are also σB-regulated. Diclofenac altered S. aureus susceptibility to multiple antibiotics in a strain-dependent manner. Susceptibility increased for ciprofloxacin, ofloxacin and norfloxacin, decreased for oxacillin and vancomycin, and did not change for tetracycline or chloramphenicol. Mutation to DcRS did not affect susceptibility to the above antibiotics. Reduced ciprofloxacin MICs with diclofenac in strain BB255, were not associated with increased drug accumulation. Conclusions The results of

  3. Occurrence, Seasonal Variation and Risk Assessment of Antibiotics in Qingcaosha Reservoir

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    Yue Jiang

    2018-01-01

    Full Text Available Qingcaosha Reservoir is an important drinking water source in Shanghai. The occurrence of five groups of antibiotics was investigated in the surface water of this reservoir over a one-year period. Seventeen antibiotics were selected in this study based on their significant usage in China. Of these antibiotics, 16 were detected, while oxytetracycline was not detected in any sampling site. The detected frequency of tylosin was only 47.92% while the other 15 antibiotics were above 81.25%. The dominant antibiotic was different in four seasons: norfloxacin was dominant in spring, and penicillinV was dominant in summer, autumn and winter, with medium concentrations of 124.10 ng/L, 89.91 ng/L, 180.28 ng/L, and 216.43 ng/L, respectively. The concentrations and detection frequencies of antibiotics were notably higher in winter than in other seasons, demonstrating that low temperature and low flow may result in the persistence of antibiotics in the aquatic environment. Risk assessment suggested that norfloxacin, ciprofloxacin, penicillinV, and doxycycline in the surface water presented high ecological risks.

  4. Sorption and biodegradation of sulfonamide antibiotics by activated sludge: experimental assessment using batch data obtained under aerobic conditions.

    Science.gov (United States)

    Yang, Sheng-Fu; Lin, Cheng-Fang; Lin, Angela Yu-Chen; Hong, Pui-Kwan Andy

    2011-05-01

    This study investigated the adsorption, desorption, and biodegradation characteristics of sulfonamide antibiotics in the presence of activated sludge with and without being subjected to NaN(3) biocide. Batch experiments were conducted and the relative contributions of adsorption and biodegradation to the observed removal of sulfonamide antibiotics were determined. Three sulfonamide antibiotics including sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamonomethoxine (SMM), which had been detected in the influent and the activated sludge of wastewater treatment plants (WWTP) in Taiwan, were selected for this study. Experimental results showed that the antibiotic compounds were removed via sorption and biodegradation by the activated sludge, though biodegradation was inhibited in the first 12 h possibly due to competitive inhibition of xenobiotic oxidation by readily biodegradable substances. The affinity of sulfonamides to sterilized sludge was in the order of SDM > SMM > SMX. The sulfonamides existed predominantly as anions at the study pH of 6.8, which resulted in a low level of adsorption to the activated sludge. The adsorption/desorption isotherms were of a linear form, as well described by the Freundlich isotherm with the n value approximating unity. The linear distribution coefficients (K(d)) were determined from batch equilibrium experiments with values of 28.6 ± 1.9, 55.7 ± 2.2, and 110.0 ± 4.6 mL/g for SMX, SMM, and SDM, respectively. SMX, SMM, and SDM desorb reversibly from the activated sludge leaving behind on the solids 0.9%, 1.6%, and 5.2% of the original sorption dose of 100 μg/L. The sorbed antibiotics can be introduced into the environment if no further treatments were employed to remove them from the biomass. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Impact of different antibiotics on methane production using waste-activated sludge: mechanisms and microbial community dynamics.

    Science.gov (United States)

    Mustapha, Nurul Asyifah; Sakai, Kenji; Shirai, Yoshihito; Maeda, Toshinari

    2016-11-01

    Anaerobic digestion is an effective method for reducing the by-product of waste-activated sludge (WAS) from wastewater treatment plants and for producing bioenergy from WAS. However, only a limited number of studies have attempted to improve anaerobic digestion by targeting the microbial interactions in WAS. In this study, we examined whether different antibiotics positively, negatively, or neutrally influence methane fermentation by evaluating changes in the microbial community and functions in WAS. Addition of azithromycin promoted the microbial communities related to the acidogenic and acetogenic stages, and a high concentration of soluble proteins and a high activity of methanogens were detected. Chloramphenicol inhibited methane production but did not affect the bacteria that contribute to the hydrolysis, acidogenesis, and acetogenesis digestion stages. The addition of kanamycin, which exhibits the same methane productivity as a control (antibiotic-free WAS), did not affect all of the microbial communities during anaerobic digestion. This study demonstrates the simultaneous functions and interactions of diverse bacteria and methanogenic Archaea in different stages of the anaerobic digestion of WAS. The ratio of Caldilinea, Methanosarcina, and Clostridium may correspond closely to the trend of methane production in each antibiotic. The changes in microbial activities and function by antibiotics facilitate a better understanding of bioenergy production.

  6. In vitro activity of fluoroquinolones (gatifloxacin, levofloxacin and trovafloxacin and seven other antibiotics against Streptococcus pneumoniae

    Directory of Open Access Journals (Sweden)

    Nicodemo A.C.

    2001-01-01

    Full Text Available In recent years, the level of resistance of S. pneumoniae to beta-lactam and/or macrolides has increased around the world including some countries in South America. Because of this resistance, it is necessary to test the therapeutic alternatives for treating this pathogen, including the newer quinolones. This study was carried out in order to compare the in vitro activity of fluoroquinolones gatifloxacin, levofloxacin and trovafloxacin, to penicillin G, amoxicillin, amoxicillin-clavulanate, cufuroxime sodium, ceftriaxone, azithromycin and clarithromycin, against 300 strains of S. pneumoniae. Of the 300 samples tested, 18.6% were not susceptible to penicillin (56 strains and 7% (21 strains were resistant to the second generation cephalosporin. Among the macrolides, resistance ranged from 6.7% for clarithromycin to 29.6% for azithromycin. Susceptibility to the newer quinolones was 100% including the 56 strains not susceptible to penicillin. Among the 10 antibiotics evaluated, the fluoroquinolones gatifloxacin, levofloxacin, and trovafloxacin displayed high levels of in vitro activity against S. pneumoniae.

  7. Valosin containing protein (VCP) interacts with macrolide antibiotics without mediating their anti-inflammatory activities.

    Science.gov (United States)

    Nujić, Krunoslav; Smith, Marjorie; Lee, Michael; Belamarić, Daniela; Tomašković, Linda; Alihodžić, Sulejman; Malnar, Ivica; Polančec, Denis; Schneider, Klaus; Eraković Haber, Vesna

    2012-02-29

    In addition to antibacterial activity, some macrolide antibiotics, such as azithromycin and clarithromycin, also exhibit anti-inflammatory properties in vitro and in vivo, although the targets and mechanism(s) of action remain unknown. The aim of the present study was to identify protein targets of azithromycin and clarithromycin which could potentially explain their anti-inflammatory effects. Using chemical proteomics approach, based on compound-immobilized affinity chromatography, valosin containing protein (VCP) was identified as a potential target of the macrolides. Validation studies confirmed the interaction of macrolides and VCP and gave some structural characteristics of this interaction. Cell based assays however, including the use of gene silencing and the study of VCP specific cellular functions in J774.A1 (murine macrophage) and IB3-1 (human cystic fibrotic epithelial) cell lines, failed to confirm an association between the binding of the macrolides to VCP and anti-inflammatory effects. These findings suggest the absence of an abundant high affinity protein target and the potential involvement of other biological molecules in the anti-inflammatory activity of macrolides. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Cationic Amphiphiles Increase Activity of Aminoglycoside Antibiotic Tobramycin in the Presence of Airway Polyelectrolytes

    International Nuclear Information System (INIS)

    Purdy Drew, Kirstin R.; Sanders, Lori K.; Culumber, Zachary W.; Zribi, Olena; Wong, Gerard C.L.

    2009-01-01

    It is empirically known that anionic polyelectrolytes present in cystic fibrosis (CF) airways due to bacterial infection significantly decrease the activity of cationic antimicrobials via electrostatic binding. In this work, we use synchrotron small-angle X-ray scattering to investigate the interaction between tobramycin, an aminoglycoside antibiotic commonly administered to CF patients via inhalation, with DNA, which is found in high concentrations in the CF airway. We find that interactions between DNA and tobramycin are significantly modified by the presence of mixtures of amphiphilic molecules. We measure a hierarchy of self-assembled structures formed between tobramycin, DNA, and the amphiphile mixtures and show how interactions between these components can be controlled. Results indicate that mixtures of cationic and negative curvature amphiphiles optimized for DNA binding via charge matching and curvature matching can competitively displace bound tobramycin from DNA and thereby drastically suppress tobramycin-DNA binding and resultant antimicrobial inactivation. Growth inhibition assays confirm the increased activity of tobramycin in the presence of DNA with the addition of the amphiphiles. These results suggest that optimized cationic amphiphile solutions have the potential to enhance antimicrobial function in highly infected environments that contain increased concentrations of anionic inflammatory polymers.

  9. Cationic Amphiphiles Increase Activity of Aminoglycoside Antibiotic Tobramycin in the Presence of Airway Polyelectrolytes

    International Nuclear Information System (INIS)

    Drew, K.R.Purdy; Sanders, L.K.; Culumber, Z.W.; Zribi, O.; Wong, G.C.L.

    2009-01-01

    It is empirically known that anionic polyelectrolytes present in cystic fibrosis (CF) airways due to bacterial infection significantly decrease the activity of cationic antimicrobials via electrostatic binding. In this work, we use synchrotron small-angle X-ray scattering to investigate the interaction between tobramycin, an aminoglycoside antibiotic commonly administered to CF patients via inhalation, with DNA, which is found in high concentrations in the CF airway. We find that interactions between DNA and tobramycin are significantly modified by the presence of mixtures of amphiphilic molecules. We measure a hierarchy of self-assembled structures formed between tobramycin, DNA, and the amphiphile mixtures and show how interactions between these components can be controlled. Results indicate that mixtures of cationic and negative curvature amphiphiles optimized for DNA binding via charge matching and curvature matching can competitively displace bound tobramycin from DNA and thereby drastically suppress tobramycin-DNA binding and resultant antimicrobial inactivation. Growth inhibition assays confirm the increased activity of tobramycin in the presence of DNA with the addition of the amphiphiles. These results suggest that optimized cationic amphiphile solutions have the potential to enhance antimicrobial function in highly infected environments that contain increased concentrations of anionic inflammatory polymers

  10. Comparison of the antibacterial activity and synergistic activity towards antibiotics of different mammalian sera.

    Science.gov (United States)

    Miglioli, P A; Pea, F; Mazzo, M; Berti, T

    1993-02-01

    The antibacterial activity against Escherichia coli ATCC 10798 and Staphylococcus aureus Mag 90 of normal sera from nine species of mammals was investigated by Avantage (Abbott). Human and rat sera showed the highest antibacterial activity against E. coli ATCC 10798, while all investigated sera did not exhibit, till the maximum concentration tested (20%), spontaneous antibacterial activity against S. aureus Mag 90. Heat inactivated sera (56 degrees C for 30 min) of all investigated species lost their antibacterial activity, but maintained their synergistic effect with sub-MICs of some antibacterial drugs, principally against E. coli ATCC 10798.

  11. Removal of five fluoroquinolone antibiotics during broiler manure composting.

    Science.gov (United States)

    Yang, Bing; Meng, Lei; Xue, Nandong

    2018-02-01

    Composting is a cost-effective approach for the removal of antibiotics from the environment; however, the consequence of this approach on fluoroquinolone antibiotics is limited. The fate of five representative fluoroquinolone antibiotics, namely ciprofloxacin, enrofloxacin, lomefloxacin, norfloxacin, and sarafloxacin, was investigated in a pilot-scale composting of broiler manure over 42 days. The effect of antibiotic concentrations (at a dose of 15, 30, or 60 mg/kg for each and a control without antibiotic addition) on the composting process was also assessed. The 42-day composting showed 45.3-75.4% of antibiotic removal with species-specific patterns. However, the observed variations in such removal among both antibiotics concentrations and composting times were not significant in most cases, possibly indicating a slight side-effect of the tested antibiotic concentrations on the composting process. To the best of our knowledge, this study is among few studies with a focus on the persistence of fluoroquinolone antibiotics during a pilot-scale composting, which warrants further study in regards to the mechanism underlying the removal of these compounds during composting.

  12. Biofilm processes in treating mariculture wastewater may be a reservoir of antibiotic resistance genes

    International Nuclear Information System (INIS)

    Li, Shuai; Zhang, Shenghua; Ye, Chengsong; Lin, Wenfang; Zhang, Menglu; Chen, Lihua; Li, Jinmei; Yu, Xin

    2017-01-01

    Antibiotics are heavily used in Chinese mariculture, but only a small portion of the added antibiotics are absorbed by living creatures. Biofilm processes are universally used in mariculture wastewater treatment. In this study, removal of antibiotics (norfloxacin, rifampicin, and oxytetracycline) from wastewater by moving bed biofilm reactors (MBBRs) and the influence of antibiotics on reactor biofilm were investigated. The results demonstrated that there was no significant effect of sub-μg/L–sub-mg/L concentrations of antibiotics on TOC removal. Moreover, the relative abundance of antibiotic resistance genes (ARGs) and antibiotic resistance bacteria (ARB) in MBBR biofilm increased because of selective pressure of antibiotics. In addition, antibiotics decreased the diversity of the biofilm bacterial community and altered bacterial community structure. These findings provide an empirical basis for the development of appropriate practices for mariculture, and suggest that disinfection and advanced oxidation should be applied to eliminate antibiotics, ARGs, and ARB from mariculture wastewater. - Highlights: • The removal of antibiotics by Moving Bed Biofilm Reactors (MBBR) was investigated. • Biofilm process such as MBBR had little effect on the removal of the antibiotics. • The antibiotics decreased the diversity of biofilm bacterial community and altered bacterial community structure. • Biofilm processes in treating mariculture wastewater may be a reservoir of antibiotic resistance genes.

  13. THE EFFECT OF GROWTH PARAMETERS ON THE ANTIBIOTIC ACTIVITY AND SPORULATION IN BACILLUS SPP. ISOLATED FROM SOIL

    Directory of Open Access Journals (Sweden)

    Alev Usta

    2013-04-01

    Full Text Available Fifty-two Bacillus strains, which were isolated from different soil samples, were screened for antibiotic properties. The Bacillus strains were checked for antibacterial properties by the cross-streak method against 5 test pathogens, and 25 Bacillus strains had an effect on the test microorganisms. One strain of Bacillus, which exhibited the largest inhibition zone (25 mm against Shigella sonnei, was named Bacillus sp. EA62. The antibacterial activity from Bacillus sp. EA62 was tested in six different culture media against Shigella sonnei using the agar well diffusion method. The best activity medium was selected and used for further studies. The influence of the incubation period, pH, and different glucose and nitrogen concentrations on the antibacterial activity was studied. The optimal conditions for the strongest antibiotic activity were found to be 72 hours (18 mm, pH 7.5 (23 mm, 3% glucose (25 mm, and 0.3% nitrogen concentration (23 mm. Additionally, the relationship between the antibiotic activity and sporulation was investigated. Accordingly, it was determined that the increase of the activity paralleled sporulation.

  14. Transfer of antibiotics from wastewater or animal manure to soil and edible crops.

    Science.gov (United States)

    Pan, Min; Chu, L M

    2017-12-01

    Antibiotics are added to agricultural fields worldwide through wastewater irrigation or manure application, resulting in antibiotic contamination and elevated environmental risks to terrestrial environments and humans. Most studies focused on antibiotic detection in different matrices or were conducted in a hydroponic environment. Little is known about the transfer of antibiotics from antibiotic-contaminated irrigation wastewater and animal manure to agricultural soil and edible crops. In this study, we evaluated the transfer of five different antibiotics (tetracycline, sulfamethazine, norfloxacin, erythromycin, and chloramphenicol) to different crops under two levels of antibiotic-contaminated wastewater irrigation and animal manure fertilization. The final distribution of tetracycline (TC), norfloxacin (NOR) and chloramphenicol (CAP) in the crop tissues under these four treatments were as follows: fruit > leaf/shoot > root, while an opposite order was found for sulfamethazine (SMZ) and erythromycin (ERY): root > leaf/shoot > fruit. The growth of crops could accelerate the dissipation of antibiotics by absorption from contaminated soil. A higher accumulation of antibiotics was observed in crop tissues under the wastewater treatment than under manure treatment, which was due to the continual irrigation that increased adsorption in soil and uptake by crops. The translocation of antibiotics in crops mainly depended on their physicochemical properties (e.g. log K ow ), crop species, and the concentrations of antibiotics applied to the soil. The levels of antibiotics ingested through the consumption of edible crops under the different treatments were much lower than the acceptable daily intake (ADI) levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Detection of Antibiotics and Evaluation of Antibacterial Activity with Screen-Printed Electrodes

    Directory of Open Access Journals (Sweden)

    Florentina-Daniela Munteanu

    2018-03-01

    Full Text Available This review provides a brief overview of the fabrication and properties of screen-printed electrodes and details the different opportunities to apply them for the detection of antibiotics, detection of bacteria and antibiotic susceptibility. Among the alternative approaches to costly chromatographic or ELISA methods for antibiotics detection and to lengthy culture methods for bacteria detection, electrochemical biosensors based on screen-printed electrodes present some distinctive advantages. Chemical and (biosensors for the detection of antibiotics and assays coupling detection with screen-printed electrodes with immunomagnetic separation are described. With regards to detection of bacteria, the emphasis is placed on applications targeting viable bacterial cells. While the electrochemical sensors and biosensors face many challenges before replacing standard analysis methods, the potential of screen-printed electrodes is increasingly exploited and more applications are anticipated to advance towards commercial analytical tools.

  16. Evaluation of the Antimicrobial Activity of Different Antibiotics Enhanced with Silver-Doped Hydroxyapatite Thin Films

    Directory of Open Access Journals (Sweden)

    Daniela Predoi

    2016-09-01

    Full Text Available The inhibitory and antimicrobial effects of silver particles have been known since ancient times. In the last few years, a major health problem has arisen due to pathogenic bacteria resistance to antimicrobial agents. The antibacterial activities of new materials including hydroxyapatite (HAp, silver-doped hydroxyapatite (Ag:HAp and various types of antibiotics such as tetracycline (T-HAp and T-Ag:HAp or ciprofloxacin (C-HAp and C-Ag:HAp have not been studied so far. In this study we reported, for the first time, the preparation and characterization of various thin films based on hydroxyapatite and silver-doped hydroxyapatite combined with tetracycline or ciprofloxacin. The structural and chemical characterization of hydroxyapatite and silver-doped hydroxyapatite thin films has been evaluated by X-ray diffraction (XRD and Fourier transform infrared spectroscopy (FTIR. The morphological studies of the HAp, Ag:HAp, T-HAp, T-Ag:HAp, C-HAp and C-Ag:HAp thin solid films were performed using scanning electron microscopy (SEM. In order to study the chemical composition of the coatings, energy dispersive X-ray analysis (EDX and glow discharge optical emission spectroscopy (GDOES measurements have been used, obtaining information on the distribution of the elements throughout the film. These studies have confirmed the purity of the prepared hydroxyapatite and silver-doped hydroxyapatite thin films obtained from composite targets containing Ca10−xAgx(PO46(OH2 with xAg = 0 (HAp and xAg = 0.2 (Ag:HAp. On the other hand, the major aim of this study was the evaluation of the antibacterial activities of ciprofloxacin and tetracycline in the presence of HAp and Ag:HAp thin layers against Staphylococcus aureus and Escherichia coli strains. The antibacterial activities of ciprofloxacin and tetracycline against Staphylococcus aureus and Escherichia coli test strains increased in the presence of HAp and Ag:HAp thin layers.

  17. The antibiotic polymyxin B exhibits novel antifungal activity against Fusarium species.

    Science.gov (United States)

    Hsu, Li-Hang; Wang, Hsuan-Fu; Sun, Pei-Lun; Hu, Fung-Rong; Chen, Ying-Lien

    2017-06-01

    The genus Fusarium comprises many species, including Fusarium oxysporum, Fusarium solani, Fusarium graminearum and Fusarium verticillioides, and causes severe infections in plants and humans. In clinical settings, Fusarium is the third most frequent mould to cause invasive fungal infections after Aspergillus and the Mucorales. F. solani and F. oxysporum are the most prevalent Fusarium spp. causing clinical disease. However, few effective antifungal drugs are available to treat human and plant Fusarium infections. The cationic peptide antibiotic polymyxin B (PMB) exhibits antifungal activity against the human fungal pathogens Candida albicans and Cryptococcus neoformans, but its efficacy against Fusarium spp. is unknown. In this study, the antifungal activity of PMB was tested against 12 Fusarium strains that infect humans and plants (banana, tomato, melon, pea, wheat and maize). PMB was fungicidal against all 12 Fusarium strains, with minimum fungicidal concentrations of 32 µg/mL or 64 µg/mL for most strains tested, as evidenced by broth dilution, methylene blue staining and XTT reduction assays. PMB can reduce the germination rates of conidia, but not chlamydospores, and can cause defects in cell membrane integrity in Fusarium strains. PMB exhibits synergistic activity with posaconazole and can potentiate the effect of fluconazole, voriconazole or amphotericin B against Fusarium spp. However, PMB does not show synergistic effects with fluconazole against Fusarium spp. as it does against Candida glabrata and C. neoformans, indicating evolutionary divergence of mechanisms between yeast pathogens and the filamentous fungus Fusarium. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  18. Antibiotics and activity spaces: protocol of an exploratory study of behaviour, marginalisation and knowledge diffusion

    OpenAIRE

    Haenssgen, MJ; Charoenboon, N; Zanello, G; Mayxay, M; Reed-Tsochas, F; Jones, COH; Kosaikanont, R; Praphattong, P; Manohan, P; Lubell, Y; Newton, PN; Keomany, S; Wertheim, HFL; Lienert, J; Xayavong, T

    2018-01-01

    Background Antimicrobial resistance (AMR) is a global health priority. Leading UK and global strategy papers to fight AMR recognise its social and behavioural dimensions, but current policy responses to improve the popular use of antimicrobials (eg, antibiotics) are limited to education and awareness-raising campaigns. In response to conceptual, methodological and empirical weaknesses of this approach, we study people’s antibiotic-related health behaviour through three research questions. ...

  19. Multicomponent kinetic spectrophotometric determination of pefloxacin and norfloxacin in pharmaceutical preparations and human plasma samples with the aid of chemometrics

    Science.gov (United States)

    Ni, Yongnian; Wang, Yong; Kokot, Serge

    2008-10-01

    A spectrophotometric method for the simultaneous determination of the important pharmaceuticals, pefloxacin and its structurally similar metabolite, norfloxacin, is described for the first time. The analysis is based on the monitoring of a kinetic spectrophotometric reaction of the two analytes with potassium permanganate as the oxidant. The measurement of the reaction process followed the absorbance decrease of potassium permanganate at 526 nm, and the accompanying increase of the product, potassium manganate, at 608 nm. It was essential to use multivariate calibrations to overcome severe spectral overlaps and similarities in reaction kinetics. Calibration curves for the individual analytes showed linear relationships over the concentration ranges of 1.0-11.5 mg L -1 at 526 and 608 nm for pefloxacin, and 0.15-1.8 mg L -1 at 526 and 608 nm for norfloxacin. Various multivariate calibration models were applied, at the two analytical wavelengths, for the simultaneous prediction of the two analytes including classical least squares (CLS), principal component regression (PCR), partial least squares (PLS), radial basis function-artificial neural network (RBF-ANN) and principal component-radial basis function-artificial neural network (PC-RBF-ANN). PLS and PC-RBF-ANN calibrations with the data collected at 526 nm, were the preferred methods—%RPE T ˜ 5, and LODs for pefloxacin and norfloxacin of 0.36 and 0.06 mg L -1, respectively. Then, the proposed method was applied successfully for the simultaneous determination of pefloxacin and norfloxacin present in pharmaceutical and human plasma samples. The results compared well with those from the alternative analysis by HPLC.

  20. In Vitro Anti-Helicobacter pylori Activity of the Probiotic Strain Bacillus subtilis 3 Is Due to Secretion of Antibiotics

    Science.gov (United States)

    Pinchuk, Irina V.; Bressollier, Philippe; Verneuil, Bernard; Fenet, Bernard; Sorokulova, Irina B.; Mégraud, Francis; Urdaci, Maria C.

    2001-01-01

    A limited number of antibiotics can be used against Helicobacter pylori infection, and resistance jeopardizes the success of treatment. Therefore, a search for new agents is warranted. The use of probiotics to enhance gastrointestinal health has been proposed for many years, but the scientific basis of the prophylactic and therapeutic actions of probiotics has not yet been clearly delineated. Probiotic strain Bacillus subtilis 3, whose safety has previously been demonstrated, is known to have antagonistic properties against species of the family Enterobacteriaceae. In the present study, it was also found to inhibit H. pylori. The anti-H. pylori activity present in the cell-free supernatant was not related to pH or organic acid concentration. It was heat stable and protease insensitive. At least two antibiotics, detected by thin-layer chromatography (Rf values, 0.47 and 0.85, respectively) and confirmed by high-performance liquid chromatographic analysis, were found to be responsible for this anti-H. pylori activity. All H. pylori strains tested were sensitive to both compounds. One of these compounds was identified as amicoumacin A, an antibiotic with anti-inflammatory properties. MICs for H. pylori determined in solid and liquid media ranged between 1.7 and 6.8 μg/ml and 0.75 and 2.5 μg/ml, respectively. The underestimation of MICs determined in solid medium may be due to physicochemical instability of the antibiotic under these test conditions. An additive effect between amicoumacin A and the nonamicoumacin antibiotic against H. pylori was demonstrated. PMID:11600371

  1. Antibiotic Resistant Salmonella and Vibrio Associated with Farmed Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Sanjoy Banerjee

    2012-01-01

    Full Text Available Salmonella and Vibrio species were isolated and identified from Litopenaeus vannamei cultured in shrimp farms. Shrimp samples showed occurrence of 3.3% of Salmonella and 48.3% of Vibrio. The isolates were also screened for antibiotic resistance to oxolinic acid, sulphonamides, tetracycline, sulfamethoxazole/trimethoprim, norfloxacin, ampicillin, doxycycline hydrochloride, erythromycin, chloramphenicol, and nitrofurantoin. Salmonella enterica serovar Corvallis isolated from shrimp showed individual and multiple antibiotic resistance patterns. Five Vibrio species having individual and multiple antibiotic resistance were also identified. They were Vibrio cholerae (18.3%, V. mimicus (16.7%, V. parahaemolyticus (10%, V. vulnificus (6.7%, and V. alginolyticus (1.7%. Farm owners should be concerned about the presence of these pathogenic bacteria which also contributes to human health risk and should adopt best management practices for responsible aquaculture to ensure the quality of shrimp.

  2. ANTIBACTERIAL ACTIVITY OF SOME WILD MEDICAL PLANTS EXTRACT TO ANTIBIOTIC RESISTANT ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Lukáš Hleba

    2013-02-01

    Full Text Available Antibiotics are probably the most successful family of drugs so far developed for improving human health. Because of increasing resistance to antibiotics of many bacteria, plant extracts and plant compounds are of new interest as antiseptics and antimicrobial agents in medicine. In this study, we researched antimicrobial effects of extracts of some medical plants (Tussilagofarfara, Equisetum arvense, Sambucusnigra, Aesculushippocastanumand Taraxacumofficinale from Slovakia to antibiotic resistant and antibiotic sensitive bacteria isolated from milk of cows and mare, which were breeded in different conditions. Microorganisms which were used in this experiment we isolated from milk from conventional breeding of cows (tenE. coli strains and from ecological breeding of Lipicanmare (tenE. coli strains by sterile cotton swabs. For antibiotic susceptibility testing was used disc diffusion method according by EUCAST. After dried at room temperature we weighed 50 g of crushed medical plants (parts and it were to extract in 400 ml methanol for two weeks at room temperature. For antimicrobial susceptibility testing of medical plants extract blank discs with 6 mm diameter disc diffusion method was used. We determined that all Escherichia coli strains isolated from milk of conventional breeding of cows were resistant to ampicillin and chloramphenicol. We determined that all tested ampicillin and chloramphenicol resistant E. coli strains isolated from conventional breeding of cow showed susceptibility to all used medical plants extracts. In difference, we determined that antibiotic susceptible E. coli strains isolated from ecological breeding of Lipicanmare were susceptible to Tussilagofarfara extract only. From these results we could be conclude some observations, which could be important step in treatment of bacterial infections caused by antibiotic resistant bacteria and it could be important knowledge for treatment of livestock in conventional breeding

  3. Norfloxacin release from surfactant-free nanoparticles of poly (DL-lactide-co-glycolide) and biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, J.K. [Chosun College of Science and Technology, Gwangju (Korea); Jeong, Y.I. [Chonnam National University, Gwangju (Korea); Jang, M.K. [Suncheon National University, Suncheon (Korea); Lee, C.H. [Korea Food and Drug Administration, Seoul (Korea); Nah, J.W. [Suncheon National University, Suncheon (Korea)

    2002-07-01

    We have prepared the surfactant-free nanoparticles of poly(DL- lactide-co-glycolide)(PLGA) by dialysis method and their physicochemical properties such as particle size and drug contents were investigated against various solvent. The size of PLGA nanoparticles prepared by using dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) was smaller than that from acetone. Also, the order of drug contents was DMAc>DMF>DMSO=acetone. These phenomena could be expected from the fact that solvent affects the size of nanoparticles and drug contents. The PLGA nanoparticles have a good spherical shapes as observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Also, surfactant-free nanoparticles entrapping norfloxacin (NFx) have a good drug loading capacity without free-drug on the surface of nanoparticles confirmed by the analysis of X-ray powder diffraction. Release kinetics of NFx used as a model drug was governed not only by drug contents but also by particle size. Also, the biodegradation rate of PLGA nanoparticles prepared from DMF was faster than that prepared from acetone, indicating that the biodegradation of PLGA nanoparticles is size-dependent. (author). 25 refs., 3 tabs., 5 figs.

  4. Norfloxacin mixed solvency based solid dispersions: An in-vitro and in-vivo investigation

    Directory of Open Access Journals (Sweden)

    Ravindra Kamble

    2017-05-01

    Full Text Available Norfloxacin (NF is a synthetic fluoro-quinolone molecule that is used for the treatment of urinary tract infections. However, due to its poor aqueous solubility, it has low oral bioavailability. The aim of the present study was to improve the aqueous solubility and dissolution profile of NF by formulating its mixed-solvency based solid dispersions (SDs. The NF-loaded SDs were prepared by a solvent evaporation technique using urea, sodium benzoate and a niacinamide hydrotropic mixture. The prepared SDs were evaluated regarding their solubility, mean particle size, in-vitro drug release and oral bioavailability. The optimized batch showed a high percentage yield of 99.04% , with a mean particle size of 132.91 μm. Optimized SDs Exhibit 96.48% drug release. The oral bioavailabilities of NF from the optimized SDs, drug alone and marketed formulation were evaluated in Wistar rats at a dose of 20.0 mg/kg. In comparison to the drug alone, approximately 6.90- and 5.0-fold increases in AUC and Cmax, respectively, were observed for NF from mixed-solvency based SDs. The superior dissolution rate due to its reduced particle size may have contributed to the increased oral bioavailability. This study demonstrated that mixed-solvency may be an alternative approach for poorly soluble drugs to improve their solubility and oral bioavailability.

  5. Diverse modulation of spa transcription by cell wall active antibiotics in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Nielsen, Lene Nørby; Roggenbuck, Michael; Haaber, Jakob Krause

    2012-01-01

    ABSTRACT: BACKGROUND: The aim of this study was to investigate the effect of various classes of clinically relevant antibiotics at sub-lethal concentrations on virulence gene expression and biofilm formation in Staphylococcus aureus. FINDINGS: LacZ promoter fusions of genes related to staphylococ......ABSTRACT: BACKGROUND: The aim of this study was to investigate the effect of various classes of clinically relevant antibiotics at sub-lethal concentrations on virulence gene expression and biofilm formation in Staphylococcus aureus. FINDINGS: LacZ promoter fusions of genes related...... to staphylococcal virulence were used to monitor the effects of antibiotics on gene expression in a disc diffusion assay. The selected genes were hla and spa encoding alpha-hemolysin and Protein A, respectively and RNAIII, the effector molecule of the agr quorum sensing system. The results were confirmed...... by quantitative real-time PCR. Additionally, we monitored the effect of subinhibitory concentrations of antibiotics on the ability of S. aureus to form biofilm in a microtiter plate assay. The results show that sub-lethal antibiotic concentrations diversely modulate expression of RNAIII, hla and spa. Consistently...

  6. Antibacterial and Antibiotic-Modifying Activity of Methanol Extracts from Six Cameroonian Food Plants against Multidrug-Resistant Enteric Bacteria

    Directory of Open Access Journals (Sweden)

    Joachim K. Dzotam

    2017-01-01

    Full Text Available The present work was designed to investigate the antibacterial activities of methanol extracts from six Cameroonian edible plants and their synergistic effects with some commonly used antibiotics against multidrug-resistant (MDR Gram-negative bacteria expressing active efflux pumps. The extracts were subjected to qualitative phytochemical screening and the microdilution broth method was used for antibacterial assays. The results of phytochemical tests indicate that all tested crude extracts contained polyphenols, flavonoids, triterpenes, and steroids. Extracts displayed selective antibacterial activities with the minimal inhibitory concentration (MIC values ranging from 32 to 1024 μg/mL. The lowest MIC value (32 μg/mL was recorded with Coula edulis extract against E. coli AG102 and K. pneumoniae K2 and with Mangifera indica bark extract against P. aeruginosa PA01 and Citrus sinensis extract against E. coli W3110 which also displayed the best MBC (256 μg/mL value against E. coli ATCC8739. In combination with antibiotics, extracts from M. indica leaves showed synergistic effects with 75% (6/8 of the tested antibiotics against more than 80% of the tested bacteria. The findings of the present work indicate that the tested plants may be used alone or in combination in the treatment of bacterial infections including the multidrug-resistant bacteria.

  7. Labeling of antibiotics for infection diagnosis

    International Nuclear Information System (INIS)

    Benitez, A.; Roca, M.; Martin-Comin, J.

    2006-01-01

    The high impact of infection on daily clinical practice has promoted research into better and more accurate diagnostic and therapeutic methods. Localizing inflammation/infection with nuclear medicine techniques began over 40 years ago. Today, 6 7G a-scintigraphy, 9 9mT c-nanocolloid, 1 11I n and 9 9mT c in vitro labeled leukocytes, and monoclonal anti granulocyte antibodies are widely available for this purpose. While these methods are useful for localizing inflammation, they cannot always differentiate septic from aseptic processes. The ideal properties of an agent for diagnosing infection include: high specificity, early diagnosis, rapid blood clearance, ease of preparation, low toxicity, biodistribution appropriate for the disease under study, absence of immunologic response and low cost. A novel approach to infection diagnosis is the use of radiolabelled antibiotics. Antibiotics localize in the infectious focus, where they are frequently taken up and metabolized by microorganisms. The majority of the various antibiotics studied so far are those of the quinolones group (ciprofloxacin, sparfloxacin, enrofloxacin, levofloxacin, norfloxacin and ofloxacin). More recently, the labeling of ceftizoxime, a semisynthetic third generation cephalosporin, has been reported. The relevant features of labeled antibiotics in research and/or clinical infection diagnosis are the focus of this article

  8. Human Activity Determines the Presence of Integron-Associated and Antibiotic Resistance Genes in Southwestern British Columbia

    Directory of Open Access Journals (Sweden)

    Miguel I. Uyaguari-Díaz

    2018-05-01

    Full Text Available The dissemination of antibiotic resistant bacteria from anthropogenic sources into the environment poses an emerging public health threat. Antibiotic resistance genes (ARGs and gene-capturing systems such as integron-associated integrase genes (intI play a key role in alterations of microbial communities and the spread of antibiotic resistant bacteria into the environment. In order to assess the effect of anthropogenic activities on watersheds in southwestern British Columbia, the presence of putative antibiotic resistance and integrase genes was analyzed in the microbiome of agricultural, urban influenced, and protected watersheds. A metagenomics approach and high-throughput quantitative PCR (HT qPCR were used to screen for elements of resistance including ARGs and intI. Metagenomic sequencing of bacterial genomic DNA was used to characterize the resistome of microbial communities present in watersheds over a 1-year period. There was a low prevalence of ARGs relative to the microbial population (<1%. Analysis of the metagenomic sequences detected a total of 60 elements of resistance including 46 ARGs, intI1, and groEL/intI1 genes and 12 quaternary ammonium compounds (qac resistance genes across all watershed locations. The relative abundance and richness of ARGs was found to be highest in agriculture impacted watersheds compared to urban and protected watersheds. A downstream transport pattern was observed in the impacted watersheds (urban and agricultural during dry months. Similar to other reports, this study found a strong association between intI1 and ARGs (e.g., sul1, an association which may be used as a proxy for anthropogenic activities. Chemical analysis of water samples for three major groups of antibiotics was below the detection limit. However, the high richness and gene copy numbers (GCNs of ARGs in impacted sites suggest that the effects of effluents on microbial communities are occurring even at low concentrations of

  9. Human Activity Determines the Presence of Integron-Associated and Antibiotic Resistance Genes in Southwestern British Columbia.

    Science.gov (United States)

    Uyaguari-Díaz, Miguel I; Croxen, Matthew A; Luo, Zhiyao; Cronin, Kirby I; Chan, Michael; Baticados, Waren N; Nesbitt, Matthew J; Li, Shaorong; Miller, Kristina M; Dooley, Damion; Hsiao, William; Isaac-Renton, Judith L; Tang, Patrick; Prystajecky, Natalie

    2018-01-01

    The dissemination of antibiotic resistant bacteria from anthropogenic sources into the environment poses an emerging public health threat. Antibiotic resistance genes (ARGs) and gene-capturing systems such as integron-associated integrase genes ( intI ) play a key role in alterations of microbial communities and the spread of antibiotic resistant bacteria into the environment. In order to assess the effect of anthropogenic activities on watersheds in southwestern British Columbia, the presence of putative antibiotic resistance and integrase genes was analyzed in the microbiome of agricultural, urban influenced, and protected watersheds. A metagenomics approach and high-throughput quantitative PCR (HT qPCR) were used to screen for elements of resistance including ARGs and intI . Metagenomic sequencing of bacterial genomic DNA was used to characterize the resistome of microbial communities present in watersheds over a 1-year period. There was a low prevalence of ARGs relative to the microbial population (<1%). Analysis of the metagenomic sequences detected a total of 60 elements of resistance including 46 ARGs, intI1 , and groEL/ intI1 genes and 12 quaternary ammonium compounds ( qac ) resistance genes across all watershed locations. The relative abundance and richness of ARGs was found to be highest in agriculture impacted watersheds compared to urban and protected watersheds. A downstream transport pattern was observed in the impacted watersheds (urban and agricultural) during dry months. Similar to other reports, this study found a strong association between intI1 and ARGs (e.g., sul1 ), an association which may be used as a proxy for anthropogenic activities. Chemical analysis of water samples for three major groups of antibiotics was below the detection limit. However, the high richness and gene copy numbers (GCNs) of ARGs in impacted sites suggest that the effects of effluents on microbial communities are occurring even at low concentrations of antimicrobials

  10. Antibiotics in the coastal environment of the Hailing Bay region, South China Sea: Spatial distribution, source analysis and ecological risks

    International Nuclear Information System (INIS)

    Chen, Hui; Liu, Shan; Xu, Xiang-Rong; Zhou, Guang-Jie; Liu, Shuang-Shuang; Yue, Wei-Zhong; Sun, Kai-Feng; Ying, Guang-Guo

    2015-01-01

    Highlights: • Thirty-eight antibiotics were systematically investigated in marine environment. • The distribution of antibiotics was significantly correlated with COD and NO 3 –N. • Untreated domestic sewage was the primary source of antibiotics. • Fluoroquinolones showed a strong sorption capacity onto sediments. • Oxytetracycline, norfloxacin and erythromycin–H 2 O indicated high risks. - Abstract: In this study, the occurrence and spatial distribution of 38 antibiotics in surface water and sediment samples of the Hailing Bay region, South China Sea, were investigated. Twenty-one, 16 and 15 of 38 antibiotics were detected with the concentrations ranging from <0.08 (clarithromycin) to 15,163 ng/L (oxytetracycline), 2.12 (methacycline) to 1318 ng/L (erythromycin–H 2 O), <1.95 (ciprofloxacin) to 184 ng/g (chlortetracycline) in the seawater, discharged effluent and sediment samples, respectively. The concentrations of antibiotics in the water phase were correlated positively with chemical oxygen demand and nitrate. The source analysis indicated that untreated domestic sewage was the primary source of antibiotics in the study region. Fluoroquinolones showed strong sorption capacity onto sediments due to their high pseudo-partitioning coefficients. Risk assessment indicated that oxytetracycline, norfloxacin and erythromycin–H 2 O posed high risks to aquatic organisms

  11. The Influence of Efflux Pump Inhibitors on the Activity of Non-Antibiotic NSAIDS against Gram-Negative Rods.

    Directory of Open Access Journals (Sweden)

    Agnieszka E Laudy

    Full Text Available Most patients with bacterial infections suffer from fever and various pains that require complex treatments with antibiotics, antipyretics, and analgaesics. The most common drugs used to relieve these symptoms are non-steroidal anti-inflammatory drugs (NSAIDs, which are not typically considered antibiotics. Here, we investigate the effects of NSAIDs on bacterial susceptibility to antibiotics and the modulation of bacterial efflux pumps.The activity of 12 NSAID active substances, paracetamol (acetaminophen, and eight relevant medicinal products was analyzed with or without pump inhibitors against 89 strains of Gram-negative rods by determining the MICs. Furthermore, the effects of NSAIDs on the susceptibility of clinical strains to antimicrobial agents with or without PAβN (Phe-Arg-β-naphtylamide were measured.The MICs of diclofenac, mefenamic acid, ibuprofen, and naproxen, in the presence of PAβN, were significantly (≥4-fold reduced, decreasing to 25-1600 mg/L, against the majority of the studied strains. In the case of acetylsalicylic acid only for 5 and 7 out of 12 strains of P. mirabilis and E. coli, respectively, a 4-fold increase in susceptibility in the presence of PAβN was observed. The presence of Aspirin resulted in a 4-fold increase in the MIC of ofloxacin against only two strains of E. coli among 48 tested clinical strains, which included species such as E. coli, K. pneumoniae, P. aeruginosa, and S. maltophilia. Besides, the medicinal products containing the following NSAIDs, diclofenac, mefenamic acid, ibuprofen, and naproxen, did not cause the decrease of clinical strains' susceptibility to antibiotics.The effects of PAβN on the susceptibility of bacteria to NSAIDs indicate that some NSAIDs are substrates for efflux pumps in Gram-negative rods. Morever, Aspirin probably induced efflux-mediated resistance to fluoroquinolones in a few E. coli strains.

  12. Antibiotic radioprotection of mice exposed to supralethal whole-body irradiation independent of antibacterial activity

    International Nuclear Information System (INIS)

    Mastromarino, A.; Wilson, R.

    1976-01-01

    Oral administration of streptomycin, kanamycin, neomycin, or gentamicin to specific pathogen-free C57 x Af mice in their drinking water (4 mg/ml) for 2 weeks before supralethal whole-body irradiation very significantly prolonged their mean survival times (8.2 to 8.9 days vs 6.9 for controls) to values which exceed those reported for germ-free mice (7.3 days). The total fecal concentrations of aerobes and anaerobes were reduced by kanamycin, neomycin, and gentamicin. Streptomycin reduced the anaerobes significantly, but not the aerobes. Unlike germ-free mice, these antibiotic-treated mice did excrete free bile acids, products of bacterial action. Oral antibiotic treatment was ineffective in altering the transit time of the intestinal mucosal cells. Previously reported studies had indicated a correlation between decreased transit time and increased survival after irradiation. No significant correlation between mean survival time after irradiation and mucosal transit time was observed. The data demonstrate that certain antibiotics alter the character of the intestinal bacterial flora and increase protection against supralethal doses of whole-body irradiation. It is concluded that the mechanisms of radioresistance in antibiotic-treated mice and germ-free mice are different and that in both groups radioresistance is the result of more than elimination of postirradiation infection

  13. Trends in the occurrence of human and veterinary antibiotics in the sediments of the Yellow River, Hai River and Liao River in northern China

    Energy Technology Data Exchange (ETDEWEB)

    Lijun, Zhou [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Ying Guangguo, E-mail: guang-guo.ying@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Jianliang, Zhao [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Jifeng, Yang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chemistry and Chemical Engineering Department, Hunan University of Arts and Science, Changde 415000 (China); Li, Wang; Bin, Yang; Shan, Liu [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2011-07-15

    The occurrence of four classes of 17 commonly used antibiotics (including fluoroquinolones, tetracycline, sulfonamides, and macrolides) was investigated in the sediments of the Yellow River, Hai River and Liao River in northern China by using rapid resolution liquid chromatography-tandem mass spectrometry. Higher concentrations were detected for most antibiotics in the sediments of the Hai River than in the sediments of the other rivers. Norfloxacin, ofloxacin, ciprofloxacin and oxytetracycline in the three rivers were most frequently detected with concentrations up to 5770, 1290, 653 and 652 ng/g, respectively. High frequencies and concentrations of the detected antibiotics were often found in the downstream of large cities and areas influenced by feedlot and fish ponds. Good fitted linear regression equations between antibiotic concentration and sediment physicochemical properties (TOC, texture and pH) were also found, indicating that sediment properties are important factors influencing the distribution of antibiotics in the sediment of rivers. - Highlights: > Presence of four classes of commonly used antibiotics in the river sediments. > Higher concentrations in the Hai River than in the Liao River and Yellow River. > Norfloxacin, ofloxacin, ciprofloxacin and oxytetracycline most frequently detected. > High antibiotic concentrations often found in the downstream of large cities. > River sediments are an important reservoir of antibiotics. - Higher concentrations of selected antibiotics were determined in the sediments of the Hai River than in the Liao River and Yellow River.

  14. Trends in the occurrence of human and veterinary antibiotics in the sediments of the Yellow River, Hai River and Liao River in northern China

    International Nuclear Information System (INIS)

    Zhou Lijun; Ying Guangguo; Zhao Jianliang; Yang Jifeng; Wang Li; Yang Bin; Liu Shan

    2011-01-01

    The occurrence of four classes of 17 commonly used antibiotics (including fluoroquinolones, tetracycline, sulfonamides, and macrolides) was investigated in the sediments of the Yellow River, Hai River and Liao River in northern China by using rapid resolution liquid chromatography-tandem mass spectrometry. Higher concentrations were detected for most antibiotics in the sediments of the Hai River than in the sediments of the other rivers. Norfloxacin, ofloxacin, ciprofloxacin and oxytetracycline in the three rivers were most frequently detected with concentrations up to 5770, 1290, 653 and 652 ng/g, respectively. High frequencies and concentrations of the detected antibiotics were often found in the downstream of large cities and areas influenced by feedlot and fish ponds. Good fitted linear regression equations between antibiotic concentration and sediment physicochemical properties (TOC, texture and pH) were also found, indicating that sediment properties are important factors influencing the distribution of antibiotics in the sediment of rivers. - Highlights: → Presence of four classes of commonly used antibiotics in the river sediments. → Higher concentrations in the Hai River than in the Liao River and Yellow River. → Norfloxacin, ofloxacin, ciprofloxacin and oxytetracycline most frequently detected. → High antibiotic concentrations often found in the downstream of large cities. → River sediments are an important reservoir of antibiotics. - Higher concentrations of selected antibiotics were determined in the sediments of the Hai River than in the Liao River and Yellow River.

  15. Intracellular activity of the peptide antibiotic NZ2114: studies with Staphylococcus aureus and human THP-1 monocytes, and comparison with daptomycin and vancomycin

    DEFF Research Database (Denmark)

    Brinch, Karoline Sidelmann; Tulkens, Paul M; Van Bambeke, Francoise

    2010-01-01

    Staphylococcus aureus survives inside eukaryotic cells. Our objective was to assess the activity of NZ2114, a novel peptidic antibiotic, against intracellular S. aureus in comparison with established antistaphylococcal agents acting on the bacterial envelope with a distinct mechanism.......Staphylococcus aureus survives inside eukaryotic cells. Our objective was to assess the activity of NZ2114, a novel peptidic antibiotic, against intracellular S. aureus in comparison with established antistaphylococcal agents acting on the bacterial envelope with a distinct mechanism....

  16. Spectrofluorimetric quantification of bilirubin using yttrium-norfloxacin complex as a fluorescence probe in serum samples

    Energy Technology Data Exchange (ETDEWEB)

    Kamruzzaman, Mohammad; Alam, Al-Mahmnur [Department of Chemistry, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Hak Lee, Sang, E-mail: shlee@knu.ac.kr [Department of Chemistry, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Ho Kim, Young, E-mail: youngkim@knu.ac.kr [Research Institute of Advanced Energy Technology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Gyu-Man [School of Mechanical Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Hyub Oh, Sang [Center for Gas Analysis, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

    2012-11-15

    A simple and sensitive spectrofluorimetric method was developed to determine trace amounts of bilirubin (BR) using yttrium (Y{sup 3+})-norfloxacin (NFLX) complex as a fluorescence (FL) probe. NFLX can form a stable binary complex with Y{sup 3+} and markedly enhances the weak FL signal of the NFLX. The FL intensity of the Y{sup 3+}-NFLX complex decreased significantly in the presence of BR in a buffer solution at pH=7.2. Under optimal conditions, the FL intensity decreased according to the BR concentration and showed a good linear relationship in the range of 0.03-2.3 {mu}g mL{sup -1} of BR with a correlation coefficient of 0.9988. The limit of detection for the determination of BR was 2.8 ng mL{sup -1} with a relative standard deviation (RSD) of 1.55% for five replicate determination of 0.05 {mu}g mL{sup -1} BR. The presented method offers higher sensitivity with simple instrumentation and was applied successfully in detecting BR at low concentrations. Highlights: Black-Right-Pointing-Pointer Weak FL signal of NFLX was enhanced at 419 nm by forming binary complex with Y{sup 3+}. Black-Right-Pointing-Pointer The FL intensity of Y{sup 3+}-NFLX complex was quenched markedly in the presence of ATP. Black-Right-Pointing-Pointer NFLX can transfer energy to Y{sup 3+} and BR and form the Y{sup 3+}-NFLX-ATP ternary complex. Black-Right-Pointing-Pointer The reduced FL intensity of the system was correlated with the concentration of BR. Black-Right-Pointing-Pointer The method is applied to determine BR at low concentration (2.8 ng mL{sup -1}) in serum.

  17. Investigation of the inclusion behavior between p-sulfoniccalix[8]arene and norfloxacin by fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Wang Xueying; Luo Chuannan; Lv Zhen; Lu Fuguang

    2011-01-01

    The host-guest complexation between p-sulfoniccalix[8]arene (SC 8 A) and norfloxacin (NFLX) in aqueous solution was investigated by fluorescence spectroscopy. Strong fluorescence intensity of the NFLX aqueous solution alone and obvious fluorescence quenching of NFLX solution in the presence of SC 8 A were observed. The fluorescence lifetimes of NFLX and SC 8 A-NFLX inclusion complex were determined and the effect of temperature on SC 8 A-NFLX inclusion complex was studied. The static quenching of the inclusion was obtained, that is the SC 8 A can form a nonfluorescent ground-state inclusion complex with NFLX. As the results show, the combined ratio (n) was 1:1 and association constant K was 1.17x10 5 L/mol. Based on the experimental results, the mechanism of the inclusion complex was explored. The space matching, electrostatic force and hydrogen bond play important effects in the inclusion process. Subsequently, the addition of bovine serum albumin (BSA) solution led to the recovery of fluorescence intensity. It is indicated that BSA can liberate the NFLX into the solution by destructing the SC 8 A-NFLX inclusion complex. Hence SC 8 A may be used for controlled-release drug delivery in the pharmaceutical industry. - Highlights: → Fluorescence lifetimes of NFLX and SC8A-NFLX inclusion complex were determined. → Mechanism of the SC8A-NFLX inclusion complex was explored. → It is proved that SC8A can form a nonfluorescent ground-state inclusion complex with NFLX.

  18. Improving antibiotic use in daily hospital practice : The antibiotic checklist

    NARCIS (Netherlands)

    van Daalen, F.V.

    2018-01-01

    Better use of current antibiotic agents is necessary to help control antimicrobial resistance (AMR). Antibiotic stewardship programs (ASPs) are introduced to coordinate activities to measure and improve appropriate antibiotic use in daily hospital practice. This thesis shows how the introduction of

  19. Biological Activity of Carbazole Alkaloids and Essential Oil of Murraya koenigii Against Antibiotic Resistant Microbes and Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Thilahgavani Nagappan

    2011-11-01

    Full Text Available A total of three carbazole alkaloids and essential oil from the leaves of Murraya koenigii (Rutaceae were obtained and examined for their effects on the growth of five antibiotic resistant pathogenic bacteria and three tumor cell lines (MCF-7, P 388 and Hela. The structures of these carbazoles were elucidated based on spectroscopy data and compared with literature data, hence, were identified as mahanine (1, mahanimbicine (2 and mahanimbine (3. The chemical constituents of the essential oil were identified using Gas Chromatography-Mass Spectroscopy (GCMS. These compounds exhibited potent inhibition against antibiotic resistant bacteria such as Staphylococcus aureus (210P JTU, Psedomonas aeruginosa (ATCC 25619, Klebsiella pneumonia (SR1-TU, Escherchia coli (NI23 JTU and Streptococcus pneumoniae (SR16677-PRSP with significant minimum inhibition concentration (MIC values (25.0–175.0 mg/mL and minimum bacteriacidal concentrations (MBC (100.0–500.0 mg/mL. The isolated compounds showed significant antitumor activity against MCF-7, Hela and P388 cell lines. Mahanimbine (3 and essential oil in particular showed potent antibacteria and cytotoxic effect with dose dependent trends (≤5.0 μg/mL. The findings from this investigation are the first report of carbazole alkaloids’ potential against antibiotic resistant clinical bacteria, MCF-7 and P388 cell lines.

  20. Changes in antibiotic concentrations and antibiotic resistome during commercial composting of animal manures.

    Science.gov (United States)

    Xie, Wan-Ying; Yang, Xin-Ping; Li, Qian; Wu, Long-Hua; Shen, Qi-Rong; Zhao, Fang-Jie

    2016-12-01

    The over-use of antibiotics in animal husbandry in China and the concomitant enhanced selection of antibiotic resistance genes (ARGs) in animal manures are of serious concern. Thermophilic composting is an effective way of reducing hazards in organic wastes. However, its effectiveness in antibiotic degradation and ARG reduction in commercial operations remains unclear. In the present study, we determined the concentrations of 15 common veterinary antibiotics and the abundances of 213 ARGs and 10 marker genes for mobile genetic elements (MGEs) in commercial composts made from cattle, poultry and swine manures in Eastern China. High concentrations of fluoroquinolones were found in the poultry and swine composts, suggesting insufficient removal of these antibiotics by commercial thermophilic composting. Total ARGs in the cattle and poultry manures were as high as 1.9 and 5.5 copies per bacterial cell, respectively. After thermophilic composting, the ARG abundance in the mature compost decreased to 9.6% and 31.7% of that in the cattle and poultry manure, respectively. However, some ARGs (e.g. aadA, aadA2, qacEΔ1, tetL) and MGE marker genes (e.g. cintI-1, intI-1 and tnpA-04) were persistent with high abundance in the composts. The antibiotics that were detected at high levels in the composts (e.g. norfloxacin and ofloxacin) might have posed a selection pressure on ARGs. MGE marker genes were found to correlate closely with ARGs at the levels of individual gene, resistance class and total abundance, suggesting that MGEs and ARGs are closely associated in their persistence in the composts under antibiotic selection. Our research shows potential disseminations of antibiotics and ARGs via compost utilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Enhanced adsorption of ionizable antibiotics on activated carbon fiber under electrochemical assistance in continuous-flow modes.

    Science.gov (United States)

    Wang, Sitan; Li, Xiaona; Zhao, Huimin; Quan, Xie; Chen, Shuo; Yu, Hongtao

    2018-05-01

    Ionizable antibiotics have attracted serious concerns because of their variable dissociation forms and thereby rendering unique toxicity and microorganism resistance. Developing an efficient and environmentally friendly method for removing these micropollutants from environmental media remains very challenging. Here, electro-assisted adsorption onto activated carbon fiber in continuous-flow mode was used to remove three ionizable antibiotics, sulfadimethoxine (SDM), ciprofloxacin (CIP), and clarithromycin (CLA), from water. Benefiting from strengthened electrostatic interactions, the adsorption capacities for the target antibiotics (10 mg/L) in flow mode (70.9-202.2 mg/g) increased by ∼5 times under a potential of 1.0 V (SDM) or -1.0 V (CIP and CLA) relative to those of open circuit (OC) adsorption. Meanwhile, effluent concentration decreased from >100 μg/L to 9.6 μg/L with removal efficiency increasing from 99.0% to 99.9%. Moreover, high recovery efficiency of ACF up to 96.35 ± 0.65% was achieved by imposing a reverse potential (-1.0 V) relative to that used for SDM adsorption. In addition, trace levels of antibiotics (364-580 ng/L) in surface water could be removed effectively to achieve low effluent concentration (0.4-1.2 ng/L) and high removal efficiency (99.9%) upon treating up to ∼1560 bed volumes (BVs), demonstrating the potential of electro-assisted adsorption for practical application in water treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. In vitro activity of XF-73, a novel antibacterial agent, against antibiotic-sensitive and -resistant Gram-positive and Gram-negative bacterial species.

    Science.gov (United States)

    Farrell, David J; Robbins, Marion; Rhys-Williams, William; Love, William G

    2010-06-01

    The antibacterial activity of XF-73, a dicationic porphyrin drug, was investigated against a range of Gram-positive and Gram-negative bacteria with known antibiotic resistance profiles, including resistance to cell wall synthesis, protein synthesis, and DNA and RNA synthesis inhibitors as well as cell membrane-active antibiotics. Antibiotic-sensitive strains for each of the bacterial species tested were also included for comparison purposes. XF-73 was active [minimum inhibitory concentration (MIC) 0.25-4 mg/L] against all of the Gram-positive bacteria tested, irrespective of the antibiotic resistance profile of the isolates, suggesting that the mechanism of action of XF-73 is unique compared with the major antibiotic classes. Gram-negative activity was lower (MIC 1 mg/L to > 64 mg/L). Minimum bactericidal concentration data confirmed that the activity of XF-73 was bactericidal. Time-kill kinetics against healthcare-associated and community-associated meticillin-resistant Staphylococcus aureus isolates demonstrated that XF-73 was rapidly bactericidal, with > 5 log(10) kill obtained after 15 min at 2 x MIC, the earliest time point sampled. The post-antibiotic effect (PAE) for XF-73 under conditions where the PAE for vancomycin was 5.4 h. XF-73 represents a novel broad-spectrum Gram-positive antibacterial drug with potentially beneficial characteristics for the treatment and prevention of Gram-positive bacterial infections. 2010. Published by Elsevier B.V.

  3. Evaluation of synergistic activity of bovine lactoferricin with antibiotics in corneal infection.

    Science.gov (United States)

    Oo, Thein Zaw; Cole, Nerida; Garthwaite, Linda; Willcox, Mark D P; Zhu, Hua

    2010-06-01

    The objectives of this study were to determine whether a synergistic effect could be obtained in vitro between bovine lactoferricin (B-LFcin) and antibiotics against Pseudomonas aeruginosa and Staphylococcus aureus isolates from ocular infections, and to evaluate the use of B-LFcin as an adjunct to the antibiotic treatment of corneal infection in vivo. Chequerboard and time-kill assays were performed to investigate the combined effects of B-LFcin and conventional antibiotics, including ciprofloxacin, ceftazidime and gentamicin, against 17 strains of P. aeruginosa (8) and S. aureus (9) isolated from ocular infection and inflammation, and 1 reference strain of S. aureus. Corneas of C57BL/6 mice were topically challenged with a multidrug-resistant strain of P. aeruginosa. Nine hours post-challenge, mice were treated topically and hourly with either vehicle, B-LFcin, ciprofloxacin or ciprofloxacin containing B-LFcin for 8 h. Corneas were then clinically examined, and bacterial numbers and levels of myeloperoxidase (MPO) evaluated. Synergy between B-LFcin and ciprofloxacin or ceftazidime was identified in most P. aeruginosa isolates, including multidrug-resistant strains, whereas no synergistic effect was seen between B-LFcin and gentamicin. Synergy was only observed with B-LFcin and ciprofloxacin against 2/10 S. aureus strains, and there was no synergy between B-LFcin and any of the other antibiotics tested. Combined B-LFcin and ciprofloxacin treatment significantly improved the clinical outcome, and reduced bacterial numbers and MPO in infected mouse corneas. B-LFcin alone was also able to reduce levels of MPO in infected corneas. These findings indicate that B-LFcin may have advantages as an adjunct therapy with both antimicrobial and anti-inflammatory properties in the treatment of corneal infection.

  4. Crystal and molecular structure of the membrane-active antibiotic enniatin C

    International Nuclear Information System (INIS)

    Tishchenko, G.N.; Zhukhlistova, N.E.

    2000-01-01

    The crystal structure of the cyclic hexadepsipeptide antibiotic enniatin C c[-(L-MeLeu-D-Hyi) 3 -], C 34 H 59 N 3 O 9 , was established by X-ray structure analysis (sp. gr. P2 1 , a = 20.205(5) A, b = 8.702(2) A, c 25.587(6) A, γ = 97.0(5) deg., V = 4465.3(18) A 3 , Z = 4, R = 0.089 for 3601 reflections with I > 2σ(I)). The unit cell contains two independent molecules of enniatin C, one ethanol molecule disordered over two positions, and approximately two water molecules occupying four positions and forming hydrogen bonds with each other. The independent antibiotic molecules adopt virtually identical conformations similar to those observed in the structures of enniatin B and its Na,Ni-complex. These conformations are characterized by alternating upward and downward orientations of the carbonyl groups and pseudoequatorial orientations of side radicals. The Leu residues have stretched conformations. The N-methylamide groups of the independent antibiotic molecules face each other, whereas the molecules are displaced by approximately 8.4 A with respect to each other along the mean planes of the rings

  5. Structural Features Governing the Activity of Lactoferricin-Derived Peptides That Act in Synergy with Antibiotics against Pseudomonas aeruginosa In Vitro and In Vivo▿ †

    Science.gov (United States)

    Sánchez-Gómez, Susana; Japelj, Bostjan; Jerala, Roman; Moriyón, Ignacio; Fernández Alonso, Mirian; Leiva, José; Blondelle, Sylvie E.; Andrä, Jörg; Brandenburg, Klaus; Lohner, Karl; Martínez de Tejada, Guillermo

    2011-01-01

    Pseudomonas aeruginosa is naturally resistant to many antibiotics, and infections caused by this organism are a serious threat, especially to hospitalized patients. The intrinsic low permeability of P. aeruginosa to antibiotics results from the coordinated action of several mechanisms, such as the presence of restrictive porins and the expression of multidrug efflux pump systems. Our goal was to develop antimicrobial peptides with an improved bacterial membrane-permeabilizing ability, so that they enhance the antibacterial activity of antibiotics. We carried out a structure activity relationship analysis to investigate the parameters that govern the permeabilizing activity of short (8- to 12-amino-acid) lactoferricin-derived peptides. We used a new class of constitutional and sequence-dependent descriptors called PEDES (peptide descriptors from sequence) that allowed us to predict (Spearman's ρ = 0.74; P < 0.001) the permeabilizing activity of a new peptide generation. To study if peptide-mediated permeabilization could neutralize antibiotic resistance mechanisms, the most potent peptides were combined with antibiotics, and the antimicrobial activities of the combinations were determined on P. aeruginosa strains whose mechanisms of resistance to those antibiotics had been previously characterized. A subinhibitory concentration of compound P2-15 or P2-27 sensitized P. aeruginosa to most classes of antibiotics tested and counteracted several mechanisms of antibiotic resistance, including loss of the OprD porin and overexpression of several multidrug efflux pump systems. Using a mouse model of lethal infection, we demonstrated that whereas P2-15 and erythromycin were unable to protect mice when administered separately, concomitant administration of the compounds afforded long-lasting protection to one-third of the animals. PMID:20956602

  6. Structural features governing the activity of lactoferricin-derived peptides that act in synergy with antibiotics against Pseudomonas aeruginosa in vitro and in vivo.

    Science.gov (United States)

    Sánchez-Gómez, Susana; Japelj, Bostjan; Jerala, Roman; Moriyón, Ignacio; Fernández Alonso, Mirian; Leiva, José; Blondelle, Sylvie E; Andrä, Jörg; Brandenburg, Klaus; Lohner, Karl; Martínez de Tejada, Guillermo

    2011-01-01

    Pseudomonas aeruginosa is naturally resistant to many antibiotics, and infections caused by this organism are a serious threat, especially to hospitalized patients. The intrinsic low permeability of P. aeruginosa to antibiotics results from the coordinated action of several mechanisms, such as the presence of restrictive porins and the expression of multidrug efflux pump systems. Our goal was to develop antimicrobial peptides with an improved bacterial membrane-permeabilizing ability, so that they enhance the antibacterial activity of antibiotics. We carried out a structure activity relationship analysis to investigate the parameters that govern the permeabilizing activity of short (8- to 12-amino-acid) lactoferricin-derived peptides. We used a new class of constitutional and sequence-dependent descriptors called PEDES (peptide descriptors from sequence) that allowed us to predict (Spearman's ρ = 0.74; P < 0.001) the permeabilizing activity of a new peptide generation. To study if peptide-mediated permeabilization could neutralize antibiotic resistance mechanisms, the most potent peptides were combined with antibiotics, and the antimicrobial activities of the combinations were determined on P. aeruginosa strains whose mechanisms of resistance to those antibiotics had been previously characterized. A subinhibitory concentration of compound P2-15 or P2-27 sensitized P. aeruginosa to most classes of antibiotics tested and counteracted several mechanisms of antibiotic resistance, including loss of the OprD porin and overexpression of several multidrug efflux pump systems. Using a mouse model of lethal infection, we demonstrated that whereas P2-15 and erythromycin were unable to protect mice when administered separately, concomitant administration of the compounds afforded long-lasting protection to one-third of the animals.

  7. Do piperacillin/tazobactam and other antibiotics with inhibitory activity against Clostridium difficile reduce the risk for acquisition of C. difficile colonization?

    Science.gov (United States)

    Kundrapu, Sirisha; Sunkesula, Venkata C K; Jury, Lucy A; Cadnum, Jennifer L; Nerandzic, Michelle M; Musuuza, Jackson S; Sethi, Ajay K; Donskey, Curtis J

    2016-04-18

    Systemic antibiotics vary widely in in vitro activity against Clostridium difficile. Some agents with activity against C. difficile (e.g., piperacillin/tazobactam) inhibit establishment of colonization in mice. We tested the hypothesis that piperacillin/tazobactam and other agents with activity against C. difficile achieve sufficient concentrations in the intestinal tract to inhibit colonization in patients. Point-prevalence culture surveys were conducted to compare the frequency of asymptomatic rectal carriage of toxigenic C. difficile among patients receiving piperacillin/tazobactam or other inhibitory antibiotics (e.g. ampicillin, linezolid, carbapenems) versus antibiotics lacking activity against C. difficile (e.g., cephalosporins, ciprofloxacin). For a subset of patients, in vitro inhibition of C. difficile (defined as a reduction in concentration after inoculation of vegetative C. difficile into fresh stool suspensions) was compared among antibiotic treatment groups. Of 250 patients, 32 (13 %) were asymptomatic carriers of C. difficile. In comparison to patients receiving non-inhibitory antibiotics or prior antibiotics within 90 days, patients currently receiving piperacillin/tazobactam were less likely to be asymptomatic carriers (1/36, 3 versus 7/36, 19 and 15/69, 22 %, respectively; P = 0.024) and more likely to have fecal suspensions with in vitro inhibitory activity against C. difficile (20/28, 71 versus 3/11, 27 and 4/26, 15 %; P = 0.03). Patients receiving other inhibitory antibiotics were not less likely to be asymptomatic carriers than those receiving non-inhibitory antibiotics. Our findings suggest that piperacillin/tazobactam achieves sufficient concentrations in the intestinal tract to inhibit C. difficile colonization during therapy.

  8. Phytochemical Analysis and Modulation of Antibiotic Activity by Luehea paniculata Mart. & Zucc. (Malvaceae) in Multiresistant Clinical Isolates of Candida Spp.

    Science.gov (United States)

    Calixto Júnior, João T.; Morais, Selene M.; Martins, Clécio G.; Vieira, Larissa G.; Morais-Braga, Maria Flaviana B.; Carneiro, Joara N. P.; Machado, Antonio J. P.; Menezes, Irwin R. A.; Tintino, Saulo R.; Coutinho, Henrique D. M.

    2015-01-01

    The high incidence of fungal infections has led to the continuous search for new drugs. Extracts of Luehea paniculata, a tree of multiple medicinal uses, were evaluated for anti-Candida activity, as well as its modulator potential of the Fluconazole antibiotic. Chemical prospecting of ethanol extracts of leaf and bark was carried out, the quantification of total phenols and flavonoids, characterized by the HPLC-DAD technique. The rosmarinic acid and the vitexin flavonoid were observed as major constituents in ELELP and ESWELP, respectively. Antioxidant activity was also evaluated by the method of scavenging the free radical DPPH, and quercetin was used as standard, obtaining IC50 values: 0.341 (mg/mL) for ELELP and 0.235 (mg/mL) for ESWELP. The microdilution assay was performed for antifungal activity against strains of Candida albicans, C. krusei, and C. tropicalis and showed minimum inhibitory concentrations values ≥1024 μg/mL. In the modulator action of extracts on Fluconazole against multiresistant clinical isolates of Candida (subinhibitory concentration minimum of 128 μg/mL), a significant synergism was observed, indicating that the extracts potentiated the antifungal effect against C. tropicalis, where antioxidant flavonoids could be responsible. This is the first report about modifying activity of the antibiotic action of a species of the genus Luehea. PMID:25821822

  9. Effects of copper-based compounds, antibiotics and a plant activator on population sizes and spread of Clavibacter michiganensis subsp. michiganensis in greenhouse tomato seedlings

    OpenAIRE

    Milijašević Svetlana; Todorović Biljana; Potočnik Ivana; Rekanović Emil; Stepanović Miloš

    2009-01-01

    Three copper-based compounds (copper hydroxide, copper oxychloride, copper sulphate), two antibiotics (streptomycin and kasugamycin) and a plant activator (ASM) significantly reduced population sizes and spread of C. michiganensis subsp. michiganensis among tomato seedlings in the greenhouse. Streptomycin had the best effect in reducing pathogen population size in all sampling regions. Moreover, this antibiotic completely stopped the spread of C. michiganensis subsp. michiganensis in the regi...

  10. Biogenic nanoparticles bearing antibacterial activity and their synergistic effect with broad spectrum antibiotics: Emerging strategy to combat drug

    Directory of Open Access Journals (Sweden)

    Syed Baker

    2017-01-01

    Full Text Available The present study emphasizes on synthesis of bimetallic silver–gold nanoparticles from cell free supernatant of Pseudomonas veronii strain AS41G inhabiting Annona squamosa L. The synthesized nanoparticles were characterized using hyphenated techniques with UV–Visible spectra ascertained absorbance peak between 400 and 800 nm. Possible interaction of biomolecules in mediating and stabilization of nanoparticles was depicted with Fourier transform infrared spectroscopy (FTIR. X-ray diffraction (XRD displayed Bragg’s peak conferring the 100, 111, 200, and 220 facets of the face centered cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. Size and shape of the nanoparticles were determined using Transmission electron microscopy (TEM microgram with size ranging from 5 to 50 nm forming myriad shapes. Antibacterial activity of nanoparticles against significant human pathogens was conferred with well diffusion assay and its synergistic effect with standard antibiotics revealed 87.5% fold increased activity with antibiotic “bacitracin” against bacitracin resistant strains Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae followed by kanamycin with 18.5%, gentamicin with 11.15%, streptomycin with 10%, erythromycin with 9.7% and chloramphenicol with 9.4%. Thus the study concludes with biogenic and ecofriendly route for synthesizing nanoparticles with antibacterial activity against drug resistant pathogens and attributes growing interest on endophytes as an emerging source for synthesis of nanoparticles.

  11. Electrophoretic deposition of CdS coatings and their photocatalytic activities in the degradation of tetracycline antibiotic

    Energy Technology Data Exchange (ETDEWEB)

    Vázquez, A., E-mail: alejandro.lqi@gmail.com [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N, San Nicolás de los Garza, 66455 Nuevo León (Mexico); Hernández-Uresti, D.B., E-mail: ing.dianahdz@gmail.com [Universidad Autónoma de Nuevo León, CICFIM–Facultad de Ciencias Físico Matemáticas, Av. Universidad S/N, San Nicolás de los Garza, 66455 Nuevo León (Mexico); Obregón, S. [Universidad Autónoma de Nuevo León, CICFIM–Facultad de Ciencias Físico Matemáticas, Av. Universidad S/N, San Nicolás de los Garza, 66455 Nuevo León (Mexico)

    2016-11-15

    Highlights: • CdS photocatalyst was prepared by electrophoretic deposition. • The CdS coating was used in the photodegradation of antibiotics. • O{sub 2}{sup −} and ·OH radicals were responsible for the degradation of tetracycline. - Abstract: The photocatalytic activities of CdS coatings formed by electrophoretic deposition (EPD) were evaluated through the photodegradation of an antibiotic, tetracycline. First, CdS nanoparticles were synthesized under microwave irradiation of aqueous solutions containing the cadmium and sulfur precursors at stoichiometric amounts and by using trisodium citrate as stabilizer. Microwave irradiation was carried out in a conventional microwave oven at 2.45 GHz and 1650 W of nominal power, for 60 s. The CdS nanoparticles were characterized by UV–vis spectrophotometry, photoluminescence and X-ray diffraction. Electrophoretic deposition parameters were 300 mV, 600 mV and 900 mV of applied voltage between aluminum plates separated by 1 cm. The fractal dimensions of the surfaces were evaluated by atomic force microscopy and correlated to the morphological and topographic characteristics of the coatings. The photocatalytic activity of the CdS coatings was investigated by means the photodegradation of the tetracycline antibiotic under simulated sunlight irradiation. According to the results, the photoactivity of the coatings directly depends on the concentration of the precursors and the applied voltage during the deposition. The material obtained at 600 mV showed the best photocatalytic behavior, probably due to its physical properties, such as optimum load and suitable aggregate size.

  12. Bacteriocin-like inhibitory activities of seven Lactobacillus delbrueckii subsp. bulgaricus strains against antibiotic susceptible and resistant Helicobacter pylori strains.

    Science.gov (United States)

    Boyanova, L; Gergova, G; Markovska, R; Yordanov, D; Mitov, I

    2017-12-01

    The aim of the study was to detect anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains by four cell-free supernatant (CFS) types. Activity of non-neutralized and non-heat-treated (CFSs1), non-neutralized and heat-treated (CFSs2), pH neutralized, catalase-treated and non-heat-treated (CFSs3), or neutralized, catalase- and heat-treated (CFSs4) CFSs against 18 H. pylori strains (11 of which with antibiotic resistance) was evaluated. All GLB strains produced bacteriocin-like inhibitory substances (BLISs), the neutralized CFSs of two GLB strains inhibited >81% of test strains and those of four GLB strains were active against >71% of antibiotic resistant strains. Two H. pylori strains were BLIS resistant. The heating did not reduce the CFS activity. Briefly, all GLB strains evaluated produced heat-stable BLISs, although GLB and H. pylori strain susceptibility patterns exhibited differences. Bacteriocin-like inhibitory substance activity can be an advantage for the probiotic choice for H. pylori infection control. In this study, anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains was evaluated by four cell-free supernatant (CFS) types. The GLB strains produced heat-stable bacteriocin-like inhibitory substances (BLISs) with a strong anti-H. pylori activity and some neutralized, catalase- and heat-treated CFSs inhibited >83% of the test strains. Bacteriocin-like inhibitory substance production of GLB strains can render them valuable probiotics in the control of H. pylori infection. © 2017 The Society for Applied Microbiology.

  13. Efficient Absorption of Antibiotic from Aqueous Solutions over MnO2@SA/Mn Beads and Their In Situ Regeneration by Heterogeneous Fenton-Like Reaction

    Directory of Open Access Journals (Sweden)

    Yu Luo

    2017-01-01

    Full Text Available Alginate has been extensively used as absorbents due to its excellent properties. However, the practical application of pure alginate has been restricted since the saturated adsorbent has weak physical structure and could not be regenerated easily. In this study, a low-cost and renewable composite MnO2@alginate/Mn adsorbent has been prepared facilely for the absorptive removal of antibiotic wastewater. FE-SEM, FTIR, and XRD analyses were used to characterize the samples. The norfloxacin (NOR was used as an index of antibiotics. More specifically, the batch absorption efficiency of the adsorbents was evaluated by pH, contact time with different NOR concentration, and the temperature. Thus, the performance of absorption kinetic dynamics and isotherm equations were estimated for the adsorptive removal process. Parameters including ΔG0, ΔH0, and ΔS0 were utilized to describe the feasible adsorption process. To regenerate the saturated absorptive sites of the adsorbent, the heterogeneous Fenton-like reactions were trigged by introduction of H2O2. The results showed that the in situ regenerating has exhibited an excellent recycling stability. The high activity and the simple fabrication of the adsorbents make them attractive for the treatment of wastewater containing refractory organic compound and also provide fundamental basis and technology for further practical application.

  14. Biosynthesis of quinoxaline antibiotics: Purification and characterization of the quinoxaline-2-carboxylic acid activating enzyme from Streptomyces triostinicus

    International Nuclear Information System (INIS)

    Glund, K.; Schlumbohm, W.; Bapat, M.; Keller, U.

    1990-01-01

    A quinoxaline-2-carboxylic acid activating enzyme was purified to homogeneity from triostin-producing Streptomyces triostinicus. It could also be purified from quinomycin-producing Streptomyces echinatus. Triostins and quinomycins are peptide lactones that contain quinoxaline-2-carboxylic acid as chromophoric moiety. The enzyme catalyzes the ATP-pyrophosphate exchange reaction dependent on quinoxaline-2-carboxylic acid and the formation of the corresponding adenylate. Besides quinoxaline-2-carboxylic acid, the enzyme also catalyzes the formation of adenylates from quinoline-2-carboxylic acid and thieno[3,2-b]pyridine-5-carboxylic acid. No adenylates were seen from quinoline-3-carboxylic acid, quinoline-4-carboxylic acid, pyridine-2-carboxylic acid, and 2-pyrazinecarboxylic acid. Previous work revealed that quinoline-2-carboxylic acid and thieno[3,2-b]pyridine-5-carboxylic acid became efficiently incorporated into the corresponding quinoxaline antibiotic analogues in vivo. Together with the data described here, this suggests that the enzyme is part of the quinoxaline antibiotics synthesizing enzyme system. The enzyme displays a native molecular weight of 42,000, whereas in its denatured form it is a polypeptide of Mr 52,000-53,000. It resembles in its behavior actinomycin synthetase I, the chromophore activating enzyme involved in actinomycin biosynthesis

  15. In vitro bactericidal activity of Jinghua Weikang Capsule and its individual herb Chenopodium ambrosioides L. against antibiotic-resistant Helicobacter pylori.

    Science.gov (United States)

    Liu, Wei; Liu, Yu; Zhang, Xue-Zhi; Li, Ning; Cheng, Hong

    2013-01-01

    To investigate the bactericidal effects of Jinghua Weikang Capsule and its major component Chenopodium ambrosioides L. on antibiotic-resistant Helicobacter pylori. Four clinical antibiotic-resistant H. pylori strains were isolated and incubated in liquid medium containing Jinghua Weikang Capsule or Chenopodium ambrosioides L. By means of time-kill curve method, the average colony counts and bactericidal rate were calculated at time points of 0, 4, 8 and 24 h after the incubation and the time-kill curves were charted. Both Jinghua Weikang Capsule and Chenopodium ambrosioides L. at a concentration of 0.64 g/L showed obvious bactericidal effect against antibiotic-resistant H. pylori after 4 h of incubation. Jinghua Weikang Capsule and Chenopodium ambrosioides L. are considered to be active against antibiotic-resistant H. pylori in vitro.

  16. Antibiotic contamination in a typical developing city in south China: occurrence and ecological risks in the Yongjiang River impacted by tributary discharge and anthropogenic activities.

    Science.gov (United States)

    Xue, Baoming; Zhang, Ruijie; Wang, Yinghui; Liu, Xiang; Li, Jun; Zhang, Gan

    2013-06-01

    The occurrence and distribution of ten selected antibiotics from three groups (sulfonamides, macrolides, and trimethoprim) were investigated in the Yongjiang River, which flows through Nanning City, a typical developing city in China. The study also assessed the ecological risks and the potential effects caused by discharge from tributaries and anthropogenic activities. Concentrations of most of the antibiotics were elevated along the section of the river in the urban area, highlighting the significant impact of high population density and human activities on the presence of antibiotics in the environment. The concentrations in the tributaries (ranged from not detected to 1336ngL(-1)) were generally higher than those in the main stream (ranged from not detected to 78.8ngL(-1)), but both areas contained the same predominant antibiotics, revealing the importance of tributary discharge as a source of antibiotic pollution. A risk assessment for the surface water contamination revealed that sulfamethoxazole and erythromycin posed high ecological risks to the most sensitive aquatic organisms (Synechococcus leopoliensis and Pseudokirchneriella subcapitata, respectively) in the midstream and some tributaries. Most of the selected antibiotics presented high ecological risks (risk quotients up to 95) in the sediments. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. History of Antibiotics Research.

    Science.gov (United States)

    Mohr, Kathrin I

    2016-01-01

    . Whenever a new antibiotic reached the market it did not take long until scientists observed the first resistant germs. Since the marketing of the first antibiotic there is a neck-on-neck race between scientists who discover natural or develop semisynthetic and synthetic bioactive molecules and bacteria, which have developed resistance mechanisms. The emphasis of this chapter is to give an overview of the history of antibiotics research. The situation within the pre-antibiotic era as well as in the early antibiotic era will be described until the Golden Age of Antibiotics will conclude this time travel. The most important antibiotic classes, information about their discovery, activity spectrum, mode of action, resistance mechanisms, and current application will be presented.

  18. The bactericidal activity of β-lactam antibiotics is increased by metabolizable sugar species

    DEFF Research Database (Denmark)

    Thorsing, Mette; Bentin, Thomas; Givskov, Michael

    2015-01-01

    Here, the influence of metabolizable sugars on the susceptibility of Escherichia coli to β-lactam antibiotics was investigated. Notably, monitoring growth and survival of mono- and combination-treated planktonic cultures showed a 1000- to 10 000-fold higher antibacterial efficacy of carbenicillin...... and cefuroxime in the presence of certain sugars, whereas other metabolites had no effect on β-lactam sensitivity. This effect was unrelated to changes in growth rate. Light microscopy and flow cytometry profiling revealed that bacterial filaments, formed due to β-lactam-mediated inhibition of cell division......, rapidly appeared upon β-lactam mono-treatment and remained stable for up to 18 h. The presence of metabolizable sugars in the medium did not change the rate of filamentation, but led to lysis of the filaments within a few hours. No lysis occurred in E. coli mutants unable to metabolize the sugars, thus...

  19. Forgotten antibiotics

    DEFF Research Database (Denmark)

    Pulcini, Céline; Bush, Karen; Craig, William A

    2012-01-01

    In view of the alarming spread of antimicrobial resistance in the absence of new antibiotics, this study aimed at assessing the availability of potentially useful older antibiotics. A survey was performed in 38 countries among experts including hospital pharmacists, microbiologists, and infectious...

  20. Enhanced removal of sulfonamide antibiotics by KOH-activated anthracite coal: Batch and fixed-bed studies.

    Science.gov (United States)

    Zuo, Linzi; Ai, Jing; Fu, Heyun; Chen, Wei; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang

    2016-04-01

    The presence of sulfonamide antibiotics in aquatic environments poses potential risks to human health and ecosystems. In the present study, a highly porous activated carbon was prepared by KOH activation of an anthracite coal (Anth-KOH), and its adsorption properties toward two sulfonamides (sulfamethoxazole and sulfapyridine) and three smaller-sized monoaromatics (phenol, 4-nitrophenol and 1,3-dinitrobenzene) were examined in both batch and fixed-bed adsorption experiments to probe the interplay between adsorbate molecular size and adsorbent pore structure. A commercial powder microporous activated carbon (PAC) and a commercial mesoporous carbon (CMK-3) possessing distinct pore properties were included as comparative adsorbents. Among the three adsorbents Anth-KOH exhibited the largest adsorption capacities for all test adsorbates (especially the two sulfonamides) in both batch mode and fixed-bed mode. After being normalized by the adsorbent surface area, the batch adsorption isotherms of sulfonamides on PAC and Anth-KOH were displaced upward relative to the isotherms on CMK-3, likely due to the micropore-filling effect facilitated by the microporosity of adsorbents. In the fixed-bed mode, the surface area-normalized adsorption capacities of Anth-KOH for sulfonamides were close to that of CMK-3, and higher than that of PAC. The irregular, closed micropores of PAC might impede the diffusion of the relatively large-sized sulfonamide molecules and in turn led to lowered fixed-bed adsorption capacities. The overall superior adsorption of sulfonamides on Anth-KOH can be attributed to its large specific surface area (2514 m(2)/g), high pore volume (1.23 cm(3)/g) and large micropore sizes (centered at 2.0 nm). These findings imply that KOH-activated anthracite coal is a promising adsorbent for the removal of sulfonamide antibiotics from aqueous solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Linke; Na, Guangshui [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Siyu [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Kai [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Peng, E-mail: pzhang@nmemc.org.cn [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Ren, Honglei; Yao, Ziwei [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China)

    2015-09-15

    The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t{sub d,E}) and hydroxyl-radical oxidation half-lives (t{sub ·OH,E}) in sunlit surface waters. The t{sub d,E} values range from 0.56 min to 28.8 min at 45° N latitude, whereas t{sub ·OH,E} ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways.

  2. New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

    International Nuclear Information System (INIS)

    Ge, Linke; Na, Guangshui; Zhang, Siyu; Li, Kai; Zhang, Peng; Ren, Honglei; Yao, Ziwei

    2015-01-01

    The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t d,E ) and hydroxyl-radical oxidation half-lives (t ·OH,E ) in sunlit surface waters. The t d,E values range from 0.56 min to 28.8 min at 45° N latitude, whereas t ·OH,E ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways

  3. Chemistry, Antimicrobial Mechanisms, and Antibiotic Activities of Cinnamaldehyde against Pathogenic Bacteria in Animal Feeds and Human Foods.

    Science.gov (United States)

    Friedman, Mendel

    2017-12-06

    Cinnamaldehyde is a major constituent of cinnamon essential oils produced by aromatic cinnamon plants. This compound has been reported to exhibit antimicrobial properties in vitro in laboratory media and in animal feeds and human foods contaminated with disease-causing bacteria including Bacillus cereus, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. This integrated review surveys and interprets our current knowledge of the chemistry, analysis, safety, mechanism of action, and antibiotic activities of cinnamaldehyde in food animal (cattle, lambs, calves, pigs, poultry) diets and in widely consumed liquid (apple, carrot, tomato, and watermelon juices, milk) and solid foods. Solid foods include various fruits (bayberries, blueberries, raspberries, and strawberries), vegetables (carrots, celery, lettuce, spinach, cucumbers, and tomatoes), meats (beef, ham, pork, and frankfurters), poultry (chickens and turkeys), seafood (oysters and shrimp), bread, cheese, eggs, infant formula, and peanut paste. The described findings are not only of fundamental interest but also have practical implications for food safety, nutrition, and animal and human health. The collated information and suggested research needs will hopefully facilitate and guide further studies needed to optimize the use of cinnamaldehyde alone and in combination with other natural antimicrobials and medicinal antibiotics to help prevent and treat food animal and human diseases.

  4. The activity and compatibility of the antibiotic tiamulin with other drugs in poultry medicine--A review.

    Science.gov (United States)

    Islam, K M S; Klein, U; Burch, D G S

    2009-11-01

    Tiamulin hydrogen fumarate is a semisynthetic derivative of the diterpene antibiotic pleuromutilin used in poultry medicine to treat mainly Mycoplasma- and Brachyspira-related diseases. Its use over 30 yr has not generally increased the development of resistance to these pathogens but occasionally resistant isolates are encountered. Tiamulin administered at therapeutic levels is relatively quickly absorbed, metabolized in the liver, and eliminated from the body of the bird after a withdrawal period of 72 h, and as a result, meat products can be safely consumed. A zero withdrawal period for eggs has been granted in several European Union states. When administered with different drugs, tiamulin has been shown to have an enhanced activity with the tetracyclines. There is a strong interaction, even death, with the ionophore anticoccidials monensin, narasin, and salinomycin when tiamulin is used at therapeutic levels, but this is dose-related and low doses do not interact. It is thought to be caused by the preferential metabolism of tiamulin in the liver resulting in a build up of the ionophore leading to clinical signs of overdosage. Tiamulin shows a milder interaction, such as temporary growth depression, with maduramicin and semduramicin but is compatible with lasalocid. Although tiamulin shows small benefits in improving performance in healthy animals, its main production benefit is in the face of infection, as a true therapeutic antibiotic.

  5. Papulacandins, a new family of antibiotics with antifungal activity, I. Fermentation, isolation, chemical and biological characterization of papulacandins A, B, C, D and E.

    Science.gov (United States)

    Traxler, P; Gruner, J; Auden, J A

    1977-04-01

    Papulacandin, a new antibiotic complex, active against Candida albicans and several other yeasts, was isolated from a strain of Papularia sphaerosperma. The fermentation, isolation, physico-chemical properties and biological activity of the five structurally related papulacandins A, B, C, D and E are reported. Papulacandin B, the main component, was assigned the formula of C47H64O17.

  6. The Impact of Efflux Pump Inhibitors on the Activity of Selected Non-Antibiotic Medicinal Products against Gram-Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Agnieszka E. Laudy

    2017-01-01

    Full Text Available The potential role of non-antibiotic medicinal products in the treatment of multidrug-resistant Gram-negative bacteria has recently been investigated. It is highly likely that the presence of efflux pumps may be one of the reasons for the weak activity of non-antibiotics, as in the case of some non-steroidal anti-inflammatory drugs (NSAIDs, against Gram-negative rods. The activity of eight drugs of potential non-antibiotic activity, active substance standards, and relevant medicinal products were analysed with and without of efflux pump inhibitors against 180 strains of five Gram-negative rod species by minimum inhibitory concentration (MIC value determination in the presence of 1 mM MgSO4. Furthermore, the influence of non-antibiotics on the susceptibility of clinical strains to quinolones with or without PAβN (Phe-Arg-β-naphthylamide was investigated. The impacts of PAβN on the susceptibility of bacteria to non-antibiotics suggests that amitriptyline, alendronate, nicergoline, and ticlopidine are substrates of efflux pumps in Gram-negative rods. Amitriptyline/Amitriptylinum showed the highest direct antibacterial activity, with MICs ranging 100–800 mg/L against all studied species. Significant decreases in the MIC values of other active substances (acyclovir, atorvastatin, and famotidine tested with pump inhibitors were not observed. The investigated non-antibiotic medicinal products did not alter the MICs of quinolones in the absence and in the presence of PAβN to the studied clinical strains of five groups of species.

  7. Rifaximin: A reasonable alternative for norfloxacin in the prevention of spontaneous bacterial peritonitis in patients with HCV-related liver cirrhosis

    Directory of Open Access Journals (Sweden)

    Mohammed M. Shamseya

    2016-09-01

    Conclusion: Rifaximin is – at least – as good as norfloxacin. It seems to be an appropriate alternative for long-term primary and secondary prophylaxis of SBP in cirrhotic patients with ascites. Modification of dose regimen should be considered to improve patient’s compliance to rifaximin.

  8. Enhancement of Fenton processes at initial circumneutral pH for the degradation of norfloxacin with Fe@Fe2O3 core-shell nanomaterials.

    Science.gov (United States)

    Liu, Jingyi; Hu, Wenyong; Sun, Maogui; Xiong, Ouyang; Yu, Haibin; Feng, Haopeng; Wu, Xuan; Tang, Lin; Zhou, Yaoyu

    2018-06-13

    The degradation of norfloxacin by Fenton reagent with core-shell Fe@Fe 2 O 3 nanomaterials was studied under neutral conditions in a closed batch system. Norfloxacin was significantly degraded (90%) in the Fenton system with Fe@Fe 2 O 3 in 30 min at the initial pH 7.0, but slightly degraded in Fenton system without Fe@Fe 2 O 3 under the same experimental conditions. The intermediate products were investigated by gas chromatography-mass spectrometry, and the possible Fenton oxidation pathway of norfloxacin in the presence of Fe@Fe 2 O 3 nanowires was proposed. Electron spin resonance spectroscopy was used to identify and characterize the free radicals generated, and the mechanism for norfloxacin degradation was also revealed. Finally, the reusability and the stability of Fe@Fe 2 O 3 nanomaterials were studied using x-ray diffraction and scanning electron microscope, which indicated that Fe@Fe 2 O 3 is a stable catalyst and can be used repetitively in environmental pollution control.

  9. Selection of antibiotic resistance at very low antibiotic concentrations.

    Science.gov (United States)

    Sandegren, Linus

    2014-05-01

    Human use of antibiotics has driven the selective enrichment of pathogenic bacteria resistant to clinically used drugs. Traditionally, the selection of resistance has been considered to occur mainly at high, therapeutic levels of antibiotics, but we are now beginning to understand better the importance of selection of resistance at low levels of antibiotics. The concentration of an antibiotic varies in different body compartments during treatment, and low concentrations of antibiotics are found in sewage water, soils, and many water environments due to natural production and contamination from human activities. Selection of resistance at non-lethal antibiotic concentrations (below the wild-type minimum inhibitory concentration) occurs due to differences in growth rate at the particular antibiotic concentration between cells with different tolerance levels to the antibiotic. The minimum selective concentration for a particular antibiotic is reached when its reducing effect on growth of the susceptible strain balances the reducing effect (fitness cost) of the resistance determinant in the resistant strain. Recent studies have shown that resistant bacteria can be selected at concentrations several hundred-fold below the lethal concentrations for susceptible cells. Resistant mutants selected at low antibiotic concentrations are generally more fit than those selected at high concentrations but can still be highly resistant. The characteristics of selection at low antibiotic concentrations, the potential clinical problems of this mode of selection, and potential solutions will be discussed.

  10. Environmental pollution by antibiotics and by antibiotic resistance determinants

    International Nuclear Information System (INIS)

    Martinez, Jose Luis

    2009-01-01

    Antibiotics are among the most successful drugs used for human therapy. However, since they can challenge microbial populations, they must be considered as important pollutants as well. Besides being used for human therapy, antibiotics are extensively used for animal farming and for agricultural purposes. Residues from human environments and from farms may contain antibiotics and antibiotic resistance genes that can contaminate natural environments. The clearest consequence of antibiotic release in natural environments is the selection of resistant bacteria. The same resistance genes found at clinical settings are currently disseminated among pristine ecosystems without any record of antibiotic contamination. Nevertheless, the effect of antibiotics on the biosphere is wider than this and can impact the structure and activity of environmental microbiota. Along the article, we review the impact that pollution by antibiotics or by antibiotic resistance genes may have for both human health and for the evolution of environmental microbial populations. - The article reviews the current knowledge on the effects that pollution by antibiotics and antibiotic resistance genes may have for the microbiosphere.

  11. Environmental pollution by antibiotics and by antibiotic resistance determinants

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Jose Luis, E-mail: jlmtnez@cnb.csic.e [Departamento de Biotecnologia Microbiana, Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Darwin 3, Cantoblanco, 28049 Madrid, and CIBERESP (Spain)

    2009-11-15

    Antibiotics are among the most successful drugs used for human therapy. However, since they can challenge microbial populations, they must be considered as important pollutants as well. Besides being used for human therapy, antibiotics are extensively used for animal farming and for agricultural purposes. Residues from human environments and from farms may contain antibiotics and antibiotic resistance genes that can contaminate natural environments. The clearest consequence of antibiotic release in natural environments is the selection of resistant bacteria. The same resistance genes found at clinical settings are currently disseminated among pristine ecosystems without any record of antibiotic contamination. Nevertheless, the effect of antibiotics on the biosphere is wider than this and can impact the structure and activity of environmental microbiota. Along the article, we review the impact that pollution by antibiotics or by antibiotic resistance genes may have for both human health and for the evolution of environmental microbial populations. - The article reviews the current knowledge on the effects that pollution by antibiotics and antibiotic resistance genes may have for the microbiosphere.

  12. The effect of systemic antibiotics administered during the active phase of non-surgical periodontal therapy or after the healing phase: a systematic review

    Directory of Open Access Journals (Sweden)

    Aretuza FRITOLI

    2015-06-01

    Full Text Available Objective The aim of this systematic review was to compare the clinical effectiveness of systemic antibiotics administered in the active stage of periodontal treatment or after the healing phase. Material and Methods An electronic search was performed in the databases EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA statement. A manual search of the reference list of selected studies and of review articles was also performed up to November 2013. Randomized Clinical Trials (RCT that evaluated the systemic administration of antibiotics as adjuvants to scaling and root planning (SRP at different phases of periodontal treatment were included. Systematic reviews and studies that evaluated subjects with systemic diseases and those that used subantimicrobial doses of antibiotics were excluded. Results The initial search identified 1,039 articles, of which seven were selected, and only one met the inclusion criteria. This study showed that subjects taking metronidazole and amoxicillin at the initial phase of treatment exhibited statistically significantly greater reduction in pocket depth and gain in clinical attachment level in initially deep sites (PD≥7 mm than subjects taking antibiotics after healing (p<0.05. This comparison was conducted 2 months after antibiotic intake, at the healing phase. Conclusion To date, only one short-term RCT has directly compared different moments of systemic antibiotics administration, as adjuncts to SRP, in the treatment of periodontitis. Although the results of this study suggested some benefits for antibiotics intake during the active phase of therapy, these findings need to be confirmed by larger placebo-controlled randomized clinical trials with longer follow-up periods.

  13. Pattern of Infection and Antibiotic Activity among Streptococcus agalactiae Isolates from Adults in Mashhad, Iran

    Directory of Open Access Journals (Sweden)

    Masoumeh Malek-Jafarian

    2015-05-01

    Full Text Available Background: One of the main causes of sexually transmitted diseases is group B β- hemolytic streptococci (GBS multiplying in the genital tracts. Penicillin is the most common drug for the treatment of infections caused by these bacteria, but in patients suffering from Penicillin allergy, Erythromycin and Clindamycin are used as alternative therapeutic drugs against GBS. Recently, resistance to these drugs has been reported more often. In this study, efforts have been made to determine the prevalence and antibiotic resistance of GBS. Methods: Modified Christie Atkins Munch-Petersen (CAMP test was conducted on over 2400 samples of urine and discharge taken from vagina, urethra and prostate. The drug sensitivity was performed by double disk sensitivity tests to Bacitracin, Trimethoprim, and Sulfamethoxazole and then the resistant samples were investigated by E-test to determine the minimal inhibitory concentrations (MICs value. Results: Twenty-three vaginal and 10 urethral discharge, 27urine and 6 prostatic secretion samples were GBS positive. The most symbiotic microorganisms with GBS were strains of Enterococci (90%, Staphylococcus saprophyticus (25% and Candida albicans (6%. The disk diffusion method showed 18 cases with Penicillin resistance (MIC: 1.5 mg/ml. Conclusion: Taken together, GBS carriers’ rate in this study was found 20.65% (8.24% men and 12.4% women. Furthermore, findings showed high-level resistance to Erythromycin and Clindamycin.

  14. Antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Marianne Frieri

    2017-07-01

    Full Text Available Summary: Antimicrobial resistance in bacterial pathogens is a challenge that is associated with high morbidity and mortality. Multidrug resistance patterns in Gram-positive and -negative bacteria are difficult to treat and may even be untreatable with conventional antibiotics. There is currently a shortage of effective therapies, lack of successful prevention measures, and only a few new antibiotics, which require development of novel treatment options and alternative antimicrobial therapies. Biofilms are involved in multidrug resistance and can present challenges for infection control. Virulence, Staphylococcus aureus, Clostridium difficile infection, vancomycin-resistant enterococci, and control in the Emergency Department are also discussed. Keywords: Antibiotic resistance, Biofilms, Infections, Public health, Emergency Department

  15. Enhanced removal of sulfonamide antibiotics by KOH-activated anthracite coal: Batch and fixed-bed studies

    International Nuclear Information System (INIS)

    Zuo, Linzi; Ai, Jing; Fu, Heyun; Chen, Wei; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang

    2016-01-01

    The presence of sulfonamide antibiotics in aquatic environments poses potential risks to human health and ecosystems. In the present study, a highly porous activated carbon was prepared by KOH activation of an anthracite coal (Anth-KOH), and its adsorption properties toward two sulfonamides (sulfamethoxazole and sulfapyridine) and three smaller-sized monoaromatics (phenol, 4-nitrophenol and 1,3-dinitrobenzene) were examined in both batch and fixed-bed adsorption experiments to probe the interplay between adsorbate molecular size and adsorbent pore structure. A commercial powder microporous activated carbon (PAC) and a commercial mesoporous carbon (CMK-3) possessing distinct pore properties were included as comparative adsorbents. Among the three adsorbents Anth-KOH exhibited the largest adsorption capacities for all test adsorbates (especially the two sulfonamides) in both batch mode and fixed-bed mode. After being normalized by the adsorbent surface area, the batch adsorption isotherms of sulfonamides on PAC and Anth-KOH were displaced upward relative to the isotherms on CMK-3, likely due to the micropore-filling effect facilitated by the microporosity of adsorbents. In the fixed-bed mode, the surface area-normalized adsorption capacities of Anth-KOH for sulfonamides were close to that of CMK-3, and higher than that of PAC. The irregular, closed micropores of PAC might impede the diffusion of the relatively large-sized sulfonamide molecules and in turn led to lowered fixed-bed adsorption capacities. The overall superior adsorption of sulfonamides on Anth-KOH can be attributed to its large specific surface area (2514 m"2/g), high pore volume (1.23 cm"3/g) and large micropore sizes (centered at 2.0 nm). These findings imply that KOH-activated anthracite coal is a promising adsorbent for the removal of sulfonamide antibiotics from aqueous solution. - Highlights: • A high efficiency adsorbent for sulfonamide removal is prepared from anthracite. • Effects of

  16. Associations between active trachoma and community intervention with Antibiotics, Facial cleanliness, and Environmental improvement (A,F,E.

    Directory of Open Access Journals (Sweden)

    Jeremiah Ngondi

    2008-04-01

    Full Text Available Surgery, Antibiotics, Facial cleanliness and Environmental improvement (SAFE are advocated by the World Health Organization (WHO for trachoma control. However, few studies have evaluated the complete SAFE strategy, and of these, none have investigated the associations of Antibiotics, Facial cleanliness, and Environmental improvement (A,F,E interventions and active trachoma. We aimed to investigate associations between active trachoma and A,F,E interventions in communities in Southern Sudan.Surveys were undertaken in four districts after 3 years of implementation of the SAFE strategy. Children aged 1-9 years were examined for trachoma and uptake of SAFE assessed through interviews and observations. Using ordinal logistic regression, associations between signs of active trachoma and A,F,E interventions were explored. Trachomatous inflammation-intense (TI was considered more severe than trachomatous inflammation-follicular (TF. A total of 1,712 children from 25 clusters (villages were included in the analysis. Overall uptake of A,F,E interventions was: 53.0% of the eligible children had received at least one treatment with azithromycin; 62.4% children had a clean face on examination; 72.5% households reported washing faces of children two or more times a day; 73.1% households had received health education; 44.4% of households had water accessible within 30 minutes; and 6.3% households had pit latrines. Adjusting for age, sex, and district baseline prevalence of active trachoma, factors independently associated with reduced odds of a more severe active trachoma sign were: receiving three treatments with azithromycin (odds ratio [OR] = 0.1; 95% confidence interval [CI] 0.0-0.4; clean face (OR = 0.3; 95% CI 0.2-0.4; washing faces of children three or more times daily (OR = 0.4; 95% CI 0.3-0.7; and presence and use of a pit latrine in the household (OR = 0.4; 95% CI 0.2-0.9.Analysis of associations between the A,F,E components of the SAFE strategy and

  17. Investigation on Antibacterial and Antioxidant Activities, Phenolic and Flavonoid Contents of Some Thai Edible Plants as an Alternative for Antibiotics

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    J. H. Lee

    2014-10-01

    Full Text Available This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime fruits and its leaves, Sesbania grandiflora L. (Agati sesbania leaves, Piper sarmentosum Roxb (Wild betal leaves, Curcuma domestica Valeton (Turmeric roots, Morinda citrifolia L. (Beach mulberry leaves, Cassia siamea britt (Siamea cassia leaves, and Cocos nucifera L. (Coconut peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, 135 μg/mL. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of 306 μg/mL and 183 μg/mL, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% (EC50 values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and 47

  18. Alanine scan of the peptide antibiotic feglymycin: assessment of amino acid side chains contributing to antimicrobial activity.

    Science.gov (United States)

    Hänchen, Anne; Rausch, Saskia; Landmann, Benjamin; Toti, Luigi; Nusser, Antje; Süssmuth, Roderich D

    2013-03-18

    The antibiotic feglymycin is a linear 13-mer peptide synthesized by the bacterium Streptomyces sp. DSM 11171. It mainly consists of the nonproteinogenic amino acids 4-hydroxyphenylglycine and 3,5-dihydroxyphenylglycine. An alanine scan of feglymycin was performed by solution-phase peptide synthesis in order to assess the significance of individual amino acid side chains for biological activity. Hence, 13 peptides were synthesized from di- and tripeptide building blocks, and subsequently tested for antibacterial activity against Staphylococcus aureus strains. Furthermore we tested the inhibition of peptidoglycan biosynthesis enzymes MurA and MurC, which are inhibited by feglymycin. Whereas the antibacterial activity is significantly based on the three amino acids D-Hpg1, L-Hpg5, and L-Phe12, the inhibitory activity against MurA and MurC depends mainly on L-Asp13. The difference in the position dependence for antibacterial activity and enzyme inhibition suggests multiple molecular targets in the modes of action of feglymycin. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. The Comparison Among Antibacterial Activity of Mespilus germanica Extracts and Number of Common Therapeutic Antibiotics “In Vitro”

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    Farideh Tabatabaei-Yazdi

    2015-12-01

    Full Text Available Background: Antibiotic resistance is a serious and growing phenomenon in contemporary medicine and has emerged as one of the pre-eminent public health concerns of the 21st century. Objectives: In this study, antibacterial activity of Mespilus germanica extract against some pathogenic bacterial strains (Streptococcus pyogene, Listeria innocua, Enterobacter aerogenes and Klebsiella pneumoniae was evaluated. Materials and Methods: In this experimental study, maceration extraction method was used for M. germanica extract. Disk diffusion method was used to evaluate the antimicrobial effect and broth microdilution method was used to determine the minimum inhibitory concentration and minimum bactericidal concentration. Then, the data were entered into the SPSS-18 statistical software and analyzed using one-way ANOVA and Tukey test. Results: Antimicrobial activity was assessed by inhibition diameters which were found to range from 8 to 21.5 mm for the two extracts against all the bacterial strains tested. The minimum inhibitory concentrations (MIC for the extracts were later determined by three fold serial dilutions method and they ranged 2 - 64 mg/mL against all the strains and minimum bactericidal concentrations (MBC for the extracts were later determined by three fold serial dilutions method and they ranged 4 - 128 mg/mL against all the strains. Conclusions: The M. germanica extract showed the more effective impact on the growth S. pyogene and L. innocua than E. aerogenes and K. pneumoniae (P < 0.05. M. germanica in comparison with common therapeutic antibiotics had more inhibitory effect on some of the studied strains in vitro.

  20. Comparative in vitro activity of the new oxacephem antibiotic, flomoxef (6315-S).

    Science.gov (United States)

    Ruckdeschel, G; Eder, W

    1988-10-01

    The in vitro activity of flomoxef (6315-S) was determined and compared to that of different cephalosporins against 787 clinical isolates of staphylococci, Enterobacteriaceae and anaerobes. Flomoxef is similar in activity to latamoxef and cefotaxime against Enterobacteriaceae, slightly more active than cephalothin and cefamandole against oxacillin-sensitive strains of Staphylococcus aureus and minimally less active than cefamandole against oxacillin-resistant strains. Flomoxef showed similar or better activity than latamoxef and cefoxitin against most of the anaerobic species of medical importance.

  1. Antibacterial activity of exogenous glutathione and its synergism on antibiotics sensitize carbapenem-associated multidrug resistant clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Alharbe, Roaa; Almansour, Ayidh; Kwon, Dong H

    2017-10-01

    A major clinical impact of A. baumannii is hospital-acquired infections including ventilator-associated pneumonia. The treatment of this pathogen is often difficult due to its innate and acquired resistance to almost all commercially available antibiotics. Infections with carbapenem-associated multidrug resistant A. baumannii is the most problematic. Glutathione is a tripeptide thiol-antioxidant and antibacterial activity of exogenous glutathione was reported in some bacteria. However, clinical relevance and molecular details of the antibacterial activity of glutathione are currently unclear. Seventy clinical isolates of A. baumannii including 63 carbapenem-associated multidrug resistant isolates and a type strain A. baumannii ATCC 19606 were used to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Fractional inhibitory concentration (FIC) and time-killing activity with meropenem and/or glutathione were also determined in the carbapenem-associated multidrug resistant isolates. In addition, the roles of exogenous glutathione in multidrug efflux pumps and β-lactamase production were examined. Levels of MIC and MBC were ranged from 10 to 15mM of exogenous glutathione. All tested carbapenem-associated multidrug resistant isolates were sensitized by all tested antibiotics in combination with subinhibitory concentrations of glutathione. FIC levels of glutathione with carbapenem (meropenem) were allcarbapenem-associated multidrug resistant isolates were killed by subinhibitory concentrations of both glutathione and meropenem at>2log10 within 12h, suggesting glutathione synergistically interacts with meropenem. The roles of multidrug efflux pumps and β-lactamase production were excluded for the glutathione-mediated antibiotic susceptibility. Overall results demonstrate that the antibacterial activity of glutathione is clinically relevant and its synergism on antibiotics sensitizes clinical isolates of A. baumannii regardless

  2. Interaction of norfloxacin with bovine serum albumin studied by different spectrometric methods; displacement studies, molecular modeling and chemometrics approaches

    Energy Technology Data Exchange (ETDEWEB)

    Naseri, Abdolhossein, E-mail: a_naseri@tabrizu.ac.ir [Departments of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Hosseini, Soheila [Departments of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Rasoulzadeh, Farzaneh [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Rashidi, Mohammad-Reza [Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Zakery, Maryam; Khayamian, Taghi [Department of Chemistry, College of Chemistry, Isfahan University of Technology, Isfahan 84154 (Iran, Islamic Republic of)

    2015-01-15

    Serum albumins as major target proteins can bind to other ligands leading to alteration of their pharmacological properties. The mechanism of interaction between norfloxacin (NFLX) with bovine serum albumin (BSA) was investigated. Fuorescence quenching of serum albumin by this drug was found to be a static quenching process. The binding sites number, n, apparent binding constant, K, and thermodynamic parameters were calculated at different temperatures. The distance, r, between donor, BSA, and acceptor, NFLX, was calculated according to the Forster theory of non-radiation energy transfer. Also binding characteristics of NFLX with BSA together with its displacement from its binding site by kanamycin and effect of common metal ions on binding constant were investigated by the spectroscopic methods. The conformational change in the secondary structure of BSA upon interaction with NFLX was investigated qualitatively from synchronous fluorescence spectra, Fourier Transform Infrared (FTIR) and circular dichroism (CD) spectrometric methods. Molecular docking studies were performed to obtain information on the possible residues involved in the interaction process and changes in accessible surface area of the interacting residues. The results showed that the conformation of BSA changed in the presence of NFLX. For the first time, displacement studies were used for this interaction; displacement studies showed that NFLX was displaced by phenylbutazon and ketoprofen but was not displaced by ibuprofen indicating that the binding site of NFLX on albumin was site I. In addition a powerful chemometrics method, multivariate curve resolution-alternating least square, was used for resolution of spectroscopic augmented data obtained in two different titration modes in order to extract spectral information regardless of spectral overlapping of components. - Highlights: • Interaction between norfloxacin and BSA is studied by spectral methods. • Chemometrics methods are used to

  3. New insights into membrane-active action in plasma membrane of fungal hyphae by the lipopeptide antibiotic bacillomycin L.

    Science.gov (United States)

    Zhang, Bao; Dong, Chunjuan; Shang, Qingmao; Han, Yuzhu; Li, Pinglan

    2013-09-01

    Bacillomycin L, a natural iturinic lipopeptide produced by Bacillus amyloliquefaciens, is characterized by strong antifungal activities against a variety of agronomically important filamentous fungi including Rhizoctonia solani Kühn. Prior to this study, the role of membrane permeabilization in the antimicrobial activity of bacillomycin L against plant pathogenic fungi had not been investigated. To shed light on the mechanism of this antifungal activity, the permeabilization of R. solani hyphae by bacillomycin L was investigated and compared with that by amphotericin B, a polyene antibiotic which is thought to act primarily through membrane disruption. Our results derived from electron microscopy, various fluorescent techniques and gel retardation experiments revealed that the antifungal activity of bacillomycin L may be not solely a consequence of fungal membrane permeabilization, but related to the interaction of it with intracellular targets. Our findings provide more insights into the mode of action of bacillomycin L and other iturins, which could in turn help to develop new or improved antifungal formulations or result in novel strategies to prevent fungal spoilage. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  4. Antibiotic resistance monitoring in Vibrio spp. isolated from rearing environment and intestines of abalone Haliotis diversicolor.

    Science.gov (United States)

    Wang, R X; Wang, J Y; Sun, Y C; B L Yang; A L Wang

    2015-12-30

    546 Vibrio isolates from rearing seawater (292 strains) and intestines of abalone (254 strains) were tested to ten antibiotics using Kirby-Bauer diffusion method. Resistant rates of abalone-derived Vibrio isolates to chloramphenicol (C), enrofloxacin (ENX) and norfloxacin (NOR) were 40%) to kanamycin (KNA), furazolidone (F), tetracycline (TE), gentamicin (GM) and rifampin (RA). 332 isolates from seawater (n=258) and abalone (n=74) were resistant to more than three antibiotics. Peaked resistant rates of seawater-derived isolates to multiple antibiotics were overlapped in May and August. Statistical analysis showed that pH had an important effect on resistant rates of abalone-derived Vibrio isolates to RA, NOR, and ENX. Salinity and dissolved oxygen were negatively correlated with resistant rates of seawater-derived Vibrio isolates to KNA, RA, and PG. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Synergistic activity of synthetic N-terminal peptide of human lactoferrin in combination with various antibiotics against carbapenem-resistant Klebsiella pneumoniae strains.

    Science.gov (United States)

    Morici, P; Florio, W; Rizzato, C; Ghelardi, E; Tavanti, A; Rossolini, G M; Lupetti, A

    2017-10-01

    The spread of multi-drug resistant (MDR) Klebsiella pneumoniae strains producing carbapenemases points to a pressing need for new antibacterial agents. To this end, the in-vitro antibacterial activity of a synthetic N-terminal peptide of human lactoferrin, further referred to as hLF1-11, was evaluated against K. pneumoniae strains harboring different carbapenemase genes (i.e. OXA-48, KPC-2, KPC-3, VIM-1), with different susceptibility to colistin and other antibiotics, alone or in combination with conventional antibiotics (gentamicin, tigecycline, rifampicin, clindamycin, and clarithromycin). An antimicrobial peptide susceptibility assay was used to assess the bactericidal activity of hLF1-11 against the different K. pneumoniae strains tested. The synergistic activity was evaluated by a checkerboard titration method, and the fractional inhibitory concentration (FIC) index was calculated for the various combinations. hLF1-11 was more efficient in killing a K. pneumoniae strain susceptible to most antimicrobials (including colistin) than a colistin-susceptible strain and a colistin-resistant MDR K. pneumoniae strain. In addition, hLF1-11 exhibited a synergistic effect with the tested antibiotics against MDR K. pneumoniae strains. The results of this study indicate that resistance to hLF1-11 and colistin are not strictly associated, and suggest an hLF1-11-induced sensitizing effect of K. pneumoniae to antibiotics, especially to hydrophobic antibiotics, which are normally not effective on Gram-negative bacteria. Altogether, these data indicate that hLF1-11 in combination with antibiotics is a promising candidate to treat infections caused by MDR-K. pneumoniae strains.

  6. Kinetics activity of Yersinia Intermedia Against ZnO Nanoparticles Either Synergism Antibiotics by Double-Disc Synergy Test Method.

    Science.gov (United States)

    Fathi Azar Khavarani, Motahareh; Najafi, Mahla; Shakibapour, Zahra; Zaeifi, Davood

    2016-03-01

    Bacterial resistance to the commonly used antibacterial agents is an increasing challenge in the medicine, and a major problem for the health care systems; the control of their spread is a constant challenge for the hospitals. In this study, we have investigated the antimicrobial activity of the Zinc Oxide nanoparticles against clinical sample; Yersinia intermedia bacteria. Nanoparticle susceptibility constants and death kinetic were used to evaluate the antimicrobial characteristics of the Zinc Oxide (ZnO) against the bacteria. Antimicrobial tests were performed with 10 8 cfu.mL -1 at baseline. At first, Minimum Inhibitory Concentration (MIC) of ZnO was determined and then nanoparticle suspension at one and two times of the MIC was used for death kinetic and susceptibility constant assay at 0 to 360 min treatment time. ZnO nanoparticles with size ranging from 10 to 30 nm showed the highest susceptibility reaction against Y. intermedia (Z=39.06 mL.μg -1 ). The process of Y. intermedia death in ZnO suspension was assumed to follow the first-order kinetics and the survival ratio of bacteria decreased with the increasing treatment time. An increased concentration of the nanoparticle was seen to enhance the bactericidal action of the nanoparticle. Then we performed the best ratio of the nanoparticles on semi-sensitive and resistance antibiotic for the bacteria. However, based on experimental results, synergy of ZnO nanoparticles and Oxacilin was determined and Y. intermedia showed a higher sensitivity compared to the ZnO nanoparticles alone. The results of the present study illustrates that ZnO has a strong antimicrobial effect and could potentially be employed to aid the bacterial control. It could also improve- antibacterial effects in combination with the antibiotics.

  7. Antibiotics in the coastal environment of the Hailing Bay region, South China Sea: Spatial distribution, source analysis and ecological risks.

    Science.gov (United States)

    Chen, Hui; Liu, Shan; Xu, Xiang-Rong; Zhou, Guang-Jie; Liu, Shuang-Shuang; Yue, Wei-Zhong; Sun, Kai-Feng; Ying, Guang-Guo

    2015-06-15

    In this study, the occurrence and spatial distribution of 38 antibiotics in surface water and sediment samples of the Hailing Bay region, South China Sea, were investigated. Twenty-one, 16 and 15 of 38 antibiotics were detected with the concentrations ranging from antibiotics in the water phase were correlated positively with chemical oxygen demand and nitrate. The source analysis indicated that untreated domestic sewage was the primary source of antibiotics in the study region. Fluoroquinolones showed strong sorption capacity onto sediments due to their high pseudo-partitioning coefficients. Risk assessment indicated that oxytetracycline, norfloxacin and erythromycin-H2O posed high risks to aquatic organisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. In Vitro and In Vivo Antibacterial Activities of OPC-20011, a Novel Parenteral Broad-Spectrum 2-Oxaisocephem Antibiotic

    Science.gov (United States)

    Matsumoto, Makoto; Tamaoka, Hisashi; Ishikawa, Hiroshi; Kikuchi, Mikio

    1998-01-01

    OPC-20011, a new parenteral 2-oxaisocephem antibiotic, has an oxygen atom at the 2- position of the cephalosporin frame. OPC-20011 had the best antibacterial activities against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae: MICs at which 90% of the isolates were inhibited were 6.25, 6.25, and 0.05 μg/ml, respectively. Its activity is due to a high affinity of the penicillin-binding protein 2′ in MRSA, an affinity which was approximately 1,050 times as high as that for flomoxef. Against gram-negative bacteria, OPC-20011 also showed antibacterial activities similar to those of ceftazidime. The in vivo activities of OPC-20011 were comparable to or greater than those of reference compounds in murine models of systemic infection caused by gram-positive and -negative pathogens. OPC-20011 was up to 10 times as effective as vancomycin against MRSA infections in mice. This better in vivo efficacy is probably due to the bactericidal activity of OPC-20011, while vancomycin showed bacteriostatic activity against MRSA. OPC-20011 produced a significant decrease of viable counts in lung tissue at a dose of 2.5 mg/kg of body weight, an efficacy similar to that of ampicillin at a dose of 10 to 20 mg/kg on an experimental murine model of respiratory tract infection caused by non-ampicillin-susceptible S. pneumoniae T-0005. The better therapeutic efficacy of OPC-20011 was considered to be due to its potent antibacterial activity and low affinity for serum proteins of experimental animals (29% in mice and 6.4% in rats). PMID:9797230

  9. Phenotypic Resistance to Antibiotics

    Directory of Open Access Journals (Sweden)

    Jose L. Martinez

    2013-04-01

    Full Text Available The development of antibiotic resistance is usually associated with genetic changes, either to the acquisition of resistance genes, or to mutations in elements relevant for the activity of the antibiotic. However, in some situations resistance can be achieved without any genetic alteration; this is called phenotypic resistance. Non-inherited resistance is associated to specific processes such as growth in biofilms, a stationary growth phase or persistence. These situations might occur during infection but they are not usually considered in classical susceptibility tests at the clinical microbiology laboratories. Recent work has also shown that the susceptibility to antibiotics is highly dependent on the bacterial metabolism and that global metabolic regulators can modulate this phenotype. This modulation includes situations in which bacteria can be more resistant or more susceptible to antibiotics. Understanding these processes will thus help in establishing novel therapeutic approaches based on the actual susceptibility shown by bacteria during infection, which might differ from that determined in the laboratory. In this review, we discuss different examples of phenotypic resistance and the mechanisms that regulate the crosstalk between bacterial metabolism and the susceptibility to antibiotics. Finally, information on strategies currently under development for diminishing the phenotypic resistance to antibiotics of bacterial pathogens is presented.

  10. Insight into effects of antibiotics on reactor performance and evolutions of antibiotic resistance genes and microbial community in a membrane reactor.

    Science.gov (United States)

    Wen, Qinxue; Yang, Lian; Zhao, Yaqi; Huang, Long; Chen, Zhiqiang

    2018-04-01

    A lab-scale anoxic/oxic-membrane bioreactor was designed to treat antibiotics containing wastewater at different antibiotics concentrations (0.5 mg/L, 1 mg/L and 3 mg/L of each antibiotic). Overall COD and NH 4 + N removal (more than 90%) were not affected during the exposure to antibiotics and good TN removal was also achieved, while TP removal was significantly affected. The maximum removal efficiency of penicillin and chlorotetracycline reached 97.15% and 96.10% respectively due to strong hydrolysis, and sulfamethoxazole reached 90.07% by biodegradation. However, 63.87% of norfloxacin maximum removal efficiency was achieved mainly by sorption. The system had good ability to reduce ARGs, peaking to more than 4 orders of magnitude, which mainly depended on the biomass retaining of the membrane module. Antibiotics concentration influenced the evolution of ARGs and bacterial communities in the reactor. This research provides great implication to reduce ARGs and antibiotics in antibiotics containing wastewater using A/O-MBR. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes.

    Science.gov (United States)

    Ge, Linke; Na, Guangshui; Zhang, Siyu; Li, Kai; Zhang, Peng; Ren, Honglei; Yao, Ziwei

    2015-09-15

    The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (td,E) and hydroxyl-radical oxidation half-lives (tOH,E) in sunlit surface waters. The td,E values range from 0.56 min to 28.8 min at 45° N latitude, whereas tOH,E ranges from 3.24h to 33.6h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. Copyright © 2015. Published by Elsevier B.V.

  12. Does minocycline, an antibiotic with inhibitory effects on microglial activation, sharpen a sense of trust in social interaction?

    Science.gov (United States)

    Watabe, Motoki; Kato, Takahiro A; Monji, Akira; Horikawa, Hideki; Kanba, Shigenobu

    2012-04-01

    Minocycline has long been applied to various infectious diseases as a tetracycline antibiotic and recently has found new application in the treatment of brain diseases such as stroke and multiple sclerosis. In addition, minocycline has also been suggested as an effective drug for psychiatric diseases. These suggestions imply that minocycline may modulate our mental activities, while the underlying mechanism remains to be clarified. To investigate how minocycline influences human mental activity, we experimentally examined how minocycline works on human social decision making in a double-blind randomized trial. Forty-nine healthy volunteers were administered minocycline or placebo over four days, after which they played (1) a trust game, in which they decided how much to trust an anonymous partner, and (2) a dictator game, in which they decided how to divide resources between themselves and an anonymous partner. The minocycline group did not display increased trusting behavior or more altruistic resource allocation. In fact, the minocycline group displayed a slight reduction in trusting behavior. However, the minocycline group did show a strong positive correlation between the degree of risk taking in the trust game and in a separate evaluation of others' trustworthiness, whereas the placebo group showed no such correlation. These results suggest that minocycline led to more rational decision-making strategies, possibly by increasing emotion regulation. Since minocycline is a well-known inhibitor of microglial activation, our findings may open a new optional pathway for treating mental states in which a component of rational decision making is impaired.

  13. Ozonation of Cephalexin Antibiotic Using Granular Activated Carbon in a Circulating Reactor

    International Nuclear Information System (INIS)

    Amin, N. S.; Akhtar, J.

    2015-01-01

    A circulating reactor was used to decompose cephalexin during catalytic ozonation. The effect of ozone supply and granular activated carbon (GAC) catalyst was investigated for removal of CEX and COD. The regeneration of exhausted activated carbon was investigated during in-situ ozonation. According to results, ozone supply appeared as the most influencing variable followed by dosage of granular activated carbon. The BET surface area, thermogravimetric analysis (TGA) and temperature programmed desorption (TPD) curves indicated that solid phase regeneration of activated carbon using ozone gas followed by mild thermal decomposition was very effective. The adsorption capacity of regenerated activated carbon was slightly lower than virgin activated carbon. The overall study revealed that catalytic ozonation was effective in removing cephalexin from solution and the method can be applied for in-situ ozonation processes. (author)

  14. The effect of systemic antibiotics administered during the active phase of non-surgical periodontal therapy or after the healing phase: a systematic review.

    Science.gov (United States)

    Fritoli, Aretuza; Gonçalves, Cristiane; Faveri, Marcelo; Figueiredo, Luciene Cristina; Pérez-Chaparro, Paula Juliana; Fermiano, Daiane; Feres, Magda

    2015-01-01

    The aim of this systematic review was to compare the clinical effectiveness of systemic antibiotics administered in the active stage of periodontal treatment or after the healing phase. An electronic search was performed in the databases EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL), in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. A manual search of the reference list of selected studies and of review articles was also performed up to November 2013. Randomized Clinical Trials (RCT) that evaluated the systemic administration of antibiotics as adjuvants to scaling and root planning (SRP) at different phases of periodontal treatment were included. Systematic reviews and studies that evaluated subjects with systemic diseases and those that used subantimicrobial doses of antibiotics were excluded. The initial search identified 1,039 articles, of which seven were selected, and only one met the inclusion criteria. This study showed that subjects taking metronidazole and amoxicillin at the initial phase of treatment exhibited statistically significantly greater reduction in pocket depth and gain in clinical attachment level in initially deep sites (PD≥7 mm) than subjects taking antibiotics after healing (pantibiotic intake, at the healing phase. To date, only one short-term RCT has directly compared different moments of systemic antibiotics administration, as adjuncts to SRP, in the treatment of periodontitis. Although the results of this study suggested some benefits for antibiotics intake during the active phase of therapy, these findings need to be confirmed by larger placebo-controlled randomized clinical trials with longer follow-up periods.

  15. Antibacterial activity of epigallocatechin-3-gallate (EGCG) and its synergism with β-lactam antibiotics sensitizing carbapenem-associated multidrug resistant clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Lee, Spencer; Razqan, Ghaida Saleh Al; Kwon, Dong H

    2017-01-15

    Infections caused by Acinetobacter baumannii were responsive to conventional antibiotic therapy. However, recently, carbapenem-associated multidrug resistant isolates have been reported worldwide and present a major therapeutic challenge. Epigallocatechin-3-Gallate (EGCG) extracted from green tea exhibits antibacterial activity. We evaluated the antibacterial activity of EGCG and possible synergism with antibiotics in carbapenem-associated multidrug resistant A. baumannii. A potential mechanism for synergism was also explored. Seventy clinical isolates of A. baumannii collected from geographically different areas were analyzed by minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of EGCG. Checkerboard and time-killing assays were performed to exam the synergism between EGCG and antibiotics. The effects of EGCG on a multidrug efflux pump inhibitor (1-[1-naphthylmethyl] piperazine; NMP) and β-lactamase production were also examined in A. baumannii. Sixty-three of 70 clinical isolates of A. baumannii carried carbapenemase-encoding genes with carbapenem-associated multidrug resistance. Levels of MIC and MBC of EGCG ranged from 64 to 512µg/ml and from 128 to ≥1024µg/ml, respectively among the clinical isolates. MIC 90 and MBC 86 levels were 256µg/ml and 512µg/ml of EGCG, respectively. Subinhibitory concentration of EGCG in combination with all antibiotics tested, including carbapenem, sensitized (MICs fall≤1.0µg/ml) all carbapenem-associated multidrug resistant isolates. Checkerboard and time-killing assays showed synergism between EGCG and meropenem (or carbenicillin) counted as fractional inhibitory concentration of 2log10 within 12h, respectively. EGCG significantly increased the effect of NMP but was unrelated to β-lactamase production in A. baumannii, suggesting EGCG may be associated with inhibition of efflux pumps. Overall we suggest that EGCG-antibiotic combinations might provide an alternative approach to treat

  16. The effect of systemic antibiotics administered during the active phase of non-surgical periodontal therapy or after the healing phase: a systematic review

    Science.gov (United States)

    FRITOLI, Aretuza; GONÇALVES, Cristiane; FAVERI, Marcelo; FIGUEIREDO, Luciene Cristina; PÉREZ-CHAPARRO, Paula Juliana; FERMIANO, Daiane; FERES, Magda

    2015-01-01

    Objective The aim of this systematic review was to compare the clinical effectiveness of systemic antibiotics administered in the active stage of periodontal treatment or after the healing phase. Material and Methods An electronic search was performed in the databases EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL), in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. A manual search of the reference list of selected studies and of review articles was also performed up to November 2013. Randomized Clinical Trials (RCT) that evaluated the systemic administration of antibiotics as adjuvants to scaling and root planning (SRP) at different phases of periodontal treatment were included. Systematic reviews and studies that evaluated subjects with systemic diseases and those that used subantimicrobial doses of antibiotics were excluded. Results The initial search identified 1,039 articles, of which seven were selected, and only one met the inclusion criteria. This study showed that subjects taking metronidazole and amoxicillin at the initial phase of treatment exhibited statistically significantly greater reduction in pocket depth and gain in clinical attachment level in initially deep sites (PD≥7 mm) than subjects taking antibiotics after healing (pantibiotic intake, at the healing phase. Conclusion To date, only one short-term RCT has directly compared different moments of systemic antibiotics administration, as adjuncts to SRP, in the treatment of periodontitis. Although the results of this study suggested some benefits for antibiotics intake during the active phase of therapy, these findings need to be confirmed by larger placebo-controlled randomized clinical trials with longer follow-up periods. PMID:26221918

  17. Medical-grade honey enriched with antimicrobial peptides has enhanced activity against antibiotic-resistant pathogens

    NARCIS (Netherlands)

    Kwakman, P.H.S.; Boer, den L.; Ruyter-Spira, C.; Creemers-Molenaar, T.; Helsper, J.P.F.G.; Vandenbroucke-Grauls, C.M.J.E.; Zaat, S.A.J.; Velde, te A.A.

    2011-01-01

    Honey has potent activity against both antibioticsensitive and -resistant bacteria, and is an interesting agent for topical antimicrobial application to wounds. As honey is diluted by wound exudate, rapid bactericidal activity up to high dilution is a prerequisite for its successful application. We

  18. Geraniol Restores Antibiotic Activities against Multidrug-Resistant Isolates from Gram-Negative Species▿ †

    Science.gov (United States)

    Lorenzi, Vannina; Muselli, Alain; Bernardini, Antoine François; Berti, Liliane; Pagès, Jean-Marie; Amaral, Leonard; Bolla, Jean-Michel

    2009-01-01

    The essential oil of Helichrysum italicum significantly reduces the multidrug resistance of Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Combinations of the two most active fractions of the essential oil with each other or with phenylalanine arginine β-naphthylamide yield synergistic activity. Geraniol, a component of one fraction, significantly increased the efficacy of β-lactams, quinolones, and chloramphenicol. PMID:19258278

  19. [Potentialization of antibiotics by lytic enzymes].

    Science.gov (United States)

    Brisou, J; Babin, P; Babin, R

    1975-01-01

    Few lytic enzymes, specially papaine and lysozyme, acting on the membrane and cell wall structures facilitate effects of bacitracine, streptomycine and other antibiotics. Streptomycino resistant strains became sensibles to this antibiotic after contact with papaine and lysozyme. The results of tests in physiological suspensions concern only the lytic activity of enzymes. The results on nutrient medium concern together lytic, and antibiotic activities.

  20. Assessment of antibiotic susceptibilities, genotypic characteristics ...

    African Journals Online (AJOL)

    Jane

    2011-09-28

    Sep 28, 2011 ... Staphylococcus aureus and Salmonella Typhimurium ... This study was designed to evaluate the antibiotic susceptibilities, genotypic characteristics and ..... Distribution of reference and virulence genes among antibiotic-sensitive S. aureus (SAS), .... environmental factors such as temperature, water activity,.

  1. Removal of nitroimidazole antibiotics from aqueous solution by adsorption/bioadsorption on activated carbon.

    Science.gov (United States)

    Rivera-Utrilla, J; Prados-Joya, G; Sánchez-Polo, M; Ferro-García, M A; Bautista-Toledo, I

    2009-10-15

    The objective of the present study was to analyse the behaviour of activated carbon with different chemical and textural properties in nitroimidazole adsorption, also assessing the combined use of microorganisms and activated carbon in the removal of these compounds from waters and the influence of the chemical nature of the solution (pH and ionic strength) on the adsorption process. Results indicate that the adsorption of nitroimidazoles is largely determined by activated carbon chemical properties. Application of the Langmuir equation to the adsorption isotherms showed an elevated adsorption capacity (X(m)=1.04-2.04 mmol/g) for all contaminants studied. Solution pH and electrolyte concentration did not have a major effect on the adsorption of these compounds on activated carbon, confirming that the principal interactions involved in the adsorption of these compounds are non-electrostatic. Nitroimidazoles are not degraded by microorganisms used in the biological stage of a wastewater treatment plant. However, the presence of microorganisms during nitroimidazole adsorption increased their adsorption on the activated carbon, although it weakened interactions between the adsorbate and carbon surface. In dynamic regime, the adsorptive capacity of activated carbon was markedly higher in surface water and groundwater than in urban wastewaters.

  2. Antibiotic Conjugated Fluorescent Carbon Dots as a Theranostic Agent for Controlled Drug Release, Bioimaging, and Enhanced Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Mukeshchand Thakur

    2014-01-01

    Full Text Available A novel report on microwave assisted synthesis of bright carbon dots (C-dots using gum arabic (GA and its use as molecular vehicle to ferry ciprofloxacin hydrochloride, a broad spectrum antibiotic, is reported in the present work. Density gradient centrifugation (DGC was used to separate different types of C-dots. After careful analysis of the fractions obtained after centrifugation, ciprofloxacin was attached to synthesize ciprofloxacin conjugated with C-dots (Cipro@C-dots conjugate. Release of ciprofloxacin was found to be extremely regulated under physiological conditions. Cipro@C-dots were found to be biocompatible on Vero cells as compared to free ciprofloxacin (1.2 mM even at very high concentrations. Bare C-dots (∼13 mg mL−1 were used for microbial imaging of the simplest eukaryotic model—Saccharomyces cerevisiae (yeast. Bright green fluorescent was obtained when live imaging was performed to view yeast cells under fluorescent microscope suggesting C-dots incorporation inside the cells. Cipro@C-dots conjugate also showed enhanced antimicrobial activity against both model gram positive and gram negative microorganisms. Thus, the Cipro@C-dots conjugate paves not only a way for bioimaging but also an efficient new nanocarrier for controlled drug release with high antimicrobial activity, thereby serving potential tool for theranostics.

  3. Characterization of microbial community and antibiotic resistance genes in activated sludge under tetracycline and sulfamethoxazole selection pressure

    International Nuclear Information System (INIS)

    Zhang, Yingying; Geng, Jinju; Ma, Haijun; Ren, Hongqiang; Xu, Ke; Ding, Lili

    2016-01-01

    To investigate the microbial community characteristics, antibiotic resistance genes (ARGs), and bioreactor effluent quality change under tetracycline (TC) and sulfamethoxazole (SMX) selection pressure, sequencing batch reactors (SBRs) were used with environmentally relevant concentration and high-level of TC and SMX concentrations (0, 5 ppb, 50 ppb and 10 ppm). Chemical oxygen demand (COD) and ammonia nitrogen (NH_4"+−N) removals appeared unchanged (p > 0.05) with 5 and 50 ppb, but decreased significantly with 10 ppm (p tetG > sul2 > tetA > intI1 > tetS > tetC. Pearson correlation analysis showed most ARGs (tetA, tetC, tetG, tetK, tetM, sul1) were significantly correlated with intI1 (p < 0.01). - Highlights: • COD and NH_4"+−N removals significantly decrease under 10 ppm TC or SMX. • Activated sludge EPS concentrations increase with increasing TC or SMX concentrations. • TC and SMX affect the microbial community diversity of activated sludge. • Actinobacteria abundances increase with increase of TC or SMX concentration. • ARGs abundance increases with addition of TC or SMX.

  4. Antibiotics in late clinical development.

    Science.gov (United States)

    Fernandes, Prabhavathi; Martens, Evan

    2017-06-01

    Most pharmaceutical companies have stopped or have severely limited investments to discover and develop new antibiotics to treat the increasing prevalence of infections caused by multi-drug resistant bacteria, because the return on investment has been mostly negative for antibiotics that received marketing approved in the last few decades. In contrast, a few small companies have taken on this challenge and are developing new antibiotics. This review describes those antibiotics in late-stage clinical development. Most of them belong to existing antibiotic classes and a few with a narrow spectrum of activity are novel compounds directed against novel targets. The reasons for some of the past failures to find new molecules and a path forward to help attract investments to fund discovery of new antibiotics are described. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Munck, Christian

    morbidity and mortality as well as an increase in the cost of treatment. Understanding how bacteria respond to antibiotic exposure gives the foundations for a rational approach to counteract antimicrobial resistance. In the work presented in this thesis, I explore the two fundamental sources...... of antimicrobial resistance: (1) adaptive mutations and (2) horizontal acquisition of resistance genes from antibiotic gene reservoirs. By studying the geno- and phenotypic changes of E. coli in response to single and drug-pair exposures, I uncover the evolutionary trajectories leading to adaptive resistance. I...... to rationally design drug combinations that limit the evolution of antibiotic resistance due to counteracting evolutionary trajectories. My results highlight that an in-depth knowledge about the genetic responses to the individual antimicrobial compounds enables the prediction of responses to drug combinations...

  6. Antimicrobial Activity and Stability of Short and Long Based Arachnid Synthetic Peptides in the Presence of Commercial Antibiotics.

    Science.gov (United States)

    Arenas, Ivan; Villegas, Elba; Walls, Oliver; Barrios, Humberto; Rodríguez, Ramon; Corzo, Gerardo

    2016-02-17

    Four antimicrobial peptides (AMPs) named Pin2[G], Pin2[14], P18K and FA1 were chemically synthesized and purified. The four peptides were evaluated in the presence of eight commercial antibiotics against four microorganisms of medical importance: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The commercial antibiotics used were amoxicillin, azithromycin, ceftriaxone, gentamicin, levofloxacin, sulfamethoxazole, trimethoprim and vancomycin. The best AMP against P. aeruginosa was the peptide FA1, and the best AMP against S. aureus was Pin2[G]. Both FA1 and Pin2[G] were efficient against E. coli, but they were not effective against K. pneumoniae. As K. pneumoniae was resistant to most of the commercial antibiotics, combinations of the AMPs FA1 and Pin2[G] were prepared with these antibiotics. According to the fractional inhibitory concentration (FIC) index, the best antimicrobial combinations were obtained with concomitant applications of mixtures of FA1 with levofloxacin and sulfamethoxazole. However, combinations of FA1 or Pin2[G] with other antibiotics showed that total inhibitory effect of the combinations were greater than the sum of the individual effects of either the antimicrobial peptide or the antibiotic. We also evaluated the stability of the AMPs. The AMP Pin2[G] manifested the best performance in saline buffer, in supernatants of bacterial growth and in human blood plasma. Nevertheless, all AMPs were cleaved using endoproteolytic enzymes. These data show advantages and disadvantages of AMPs for potential clinical treatments of bacterial infections, using them in conjunction with commercial antibiotics.

  7. Antibiotic resistance patterns of pediatric community-acquired urinary infections

    Directory of Open Access Journals (Sweden)

    Eliana Biondi Medeiros Guidoni

    Full Text Available Knowledge about antimicrobial resistance patterns of the etiological agents of urinary tract infections (UTIs is essential for appropriate therapy. Urinary isolates from symptomatic UTI cases attended at Santa Casa University Hospital of São Paulo from August 1986 to December 1989 and August 2004 to December 2005 were identified by conventional methods. Antimicrobial resistance testing was performed by Kirby Bauer's disc diffusion method. Among the 257 children, E. coli was found in 77%. A high prevalence of resistance was observed against ampicillin and TMP/SMX (55% and 51%. The antibiotic resistance rates for E. coli were: nitrofurantoin (6%, nalidixic acid (14%, 1st generation cephalosporin (13%, 3rd generation cephalosporins (5%, aminoglycosides (2%, norfloxacin (9% and ciprofloxacin (4%. We found that E. coli was the predominant bacterial pathogen of community-acquired UTIs. We also detected increasing resistance to TMP/SMX among UTI pathogens in this population.

  8. Anti-Rhodotorula activity of mycophenolic acid enhanced in the presence of polyene antibiotic nystatin.

    Science.gov (United States)

    Kinoshita, H; Wongsuntornpoj, S; Ihara, F; Nihira, T

    2017-02-01

    Rhodotorula species are opportunistic pathogens, which cause not only systemic fungaemia but also other localized infections. Despite serious side effects such as nephrotoxicity and hypokalemia, amphotericin B (a polyene antifungal) has been commonly prescribed for Rhodotorula infection because Rhodotorula species are resistant against a candin family of antifungal agents. In this study, novel active compounds against Rhodotorula species were screened from the extracts of entomopathogenic fungi based on the synergistic effect of polyene nystatin (NYS), which causes efficient targeting of compounds due to increased permeability through the fungal cell membrane. Around 37% of culture extracts from 31 entomopathogenic fungal strains showed anti-Rhodotorula activity in the synergistic bioassay system, suggesting that the coexistence assay with NYS enhanced the discovery of anti-Rhodotorula compounds. Judging from various physicochemical data, the active component from strain HF763 was identified as an immunosuppressant drug, mycophenolic acid (MPA). The minimum inhibitory concentration of MPA against three pathogenic Rhodotorula strains was determined, focusing on the synergistic effect with NYS. The results revealed that the values decreased by at least 87% in the presence of NYS, indicating that MPA showed a synergistic effect with NYS. This study aimed to screen active compounds against Rhodotorula species that are resistant to a candin family of antifungal agents, from entomopathogenic fungi. Assuming that most of the latent antifungal compounds do not exert their activity due to their inability to penetrate the membrane, we took advantage of polyene nystatin in the screening to increase permeability through the fungal cell membrane. The result of the screening revealed hidden antifungal activity of mycophenolic acid, demonstrating that the method applied in this study unlocks the potentials of bioresources, and proposes a new remedy for mycosis. © 2016 The

  9. PF1163A and B, new antifungal antibiotics produced by Penicillium sp. I. Taxonomy of producing strain, fermentation, isolation and biological activities.

    Science.gov (United States)

    Nose, H; Seki, A; Yaguchi, T; Hosoya, A; Sasaki, T; Hoshiko, S; Shomura, T

    2000-01-01

    Two novel antifungal antibiotics, PF1163A and B, were isolated from the fermentation broth of Penicillium sp. They were purified from the solid cultures of rice media using ethyl acetate extraction, silica gel and Sephadex LH-20 column chromatographies. PF1163A and B showed potent growth inhibitory activity against pathogenic fungal strain Candida albicans but did not show cytotoxic activity against mammalian cells. These compounds inhibited the ergosterol biosynthesis in Candida albicans.

  10. Enhancement of the anticoccidial activity of polyether antibiotics in chickens by tiamulin.

    Science.gov (United States)

    Meingassner, J G; Schmook, F P; Czok, R; Mieth, H

    1979-03-01

    The anticoccidial activities of monensin and lasalocid have been studied separately and in combination with tiamulin, a new pleuromutilin derivative. Combinations of constant tiamulin concentration (.0125%) in drinking water with various levels of polyether anticoccidials (6.3 to 125 ppm) in feed and conversely of constant levels of anticoccidials with various concentrations of tiamulin were used. The prophylactic efficacy of these combined treatments in battery raised broiler chickens infected with Eimeria tenella was evaluated. Assessment of the parameters mortality, weight gain, dropping scores, lesion scores, and oocyst output showed that simultaneous application of tiamulin significantly improved the anticoccidial activity of the polyethers. As tiamulin alone is without anticoccidial activity, this phenomenon was considered to result from an interaction between tiamulin and the polyethers leading to a slower metabolic degradation of the latter. Thus tissue levels adequate for maximum anticoccidial activity would be attained with lower polyether dose levels. Experiments using isolated perfused rat liver showed that elimination of monensin was reduced by 60% in the presence of tiamulin.

  11. Consumer attitudes and use of antibiotics.

    Science.gov (United States)

    Vanden Eng, Jodi; Marcus, Ruthanne; Hadler, James L; Imhoff, Beth; Vugia, Duc J; Cieslak, Paul R; Zell, Elizabeth; Deneen, Valerie; McCombs, Katherine Gibbs; Zansky, Shelley M; Hawkins, Marguerite A; Besser, Richard E

    2003-09-01

    Recent antibiotic use is a risk factor for infection or colonization with resistant bacterial pathogens. Demand for antibiotics can be affected by consumers' knowledge, attitudes, and practices. In 1998-1999, the Foodborne Diseases Active Surveillance Network (FoodNet( conducted a population-based, random-digit dialing telephone survey, including questions regarding respondents' knowledge, attitudes, and practices of antibiotic use. Twelve percent had recently taken antibiotics; 27% believed that taking antibiotics when they had a cold made them better more quickly, 32% believed that taking antibiotics when they had a cold prevented more serious illness, and 48% expected a prescription for antibiotics when they were ill enough from a cold to seek medical attention. These misguided beliefs and expectations were associated with a lack of awareness of the dangers of antibiotic use; 58% of patients were not aware of the possible health dangers. National educational efforts are needed to address these issues if patient demand for antibiotics is to be reduced.

  12. Antimicrobial activity of biopolymer–antibiotic thin films fabricated by advanced pulsed laser methods

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Popescu, C.; Dorcioman, G.; Miroiu, F.M.; Socol, G.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Gittard, S.D.; Miller, P.R.; Narayan, R.J. [Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, NC 27599-7575 (United States); Enculescu, M. [National Institute for Materials Physics, PO Box MG-7, Bucharest-Magurele (Romania); Chrisey, D.B. [Tulane University, Department of Physics and Engineering Physics, New Orleans, LA (United States)

    2013-08-01

    We report on thin film deposition by matrix assisted pulsed laser evaporation (MAPLE) of two polymer–drug composite thin film systems. A pulsed KrF* excimer laser source (λ = 248 nm, τ = 25 ns, ν = 10 Hz) was used to deposit composite thin films of poly(D,L-lactide) (PDLLA) containing several gentamicin concentrations. FTIR spectroscopy was used to demonstrate that MAPLE-transferred materials exhibited chemical structures similar to those of drop cast materials. Scanning electron microscopy data indicated that MAPLE may be used to fabricate thin films of good morphological quality. The activity of PDLLA–gentamicin composite thin films against Staphylococcus aureus bacteria was demonstrated using drop testing. The influence of drug concentration on microbial viability was also assessed. Our studies indicate that polymer–drug composite thin films prepared by MAPLE may be used to impart antimicrobial activity to implants, medical devices, and other contact surfaces.

  13. Antimicrobial activity, antibiotic susceptibility and virulence factors of Lactic Acid Bacteria of aquatic origin intended for use as probiotics in aquaculture

    Science.gov (United States)

    2013-01-01

    Background The microorganisms intended for use as probiotics in aquaculture should exert antimicrobial activity and be regarded as safe not only for the aquatic hosts but also for their surrounding environments and humans. The objective of this work was to investigate the antimicrobial/bacteriocin activity against fish pathogens, the antibiotic susceptibility, and the prevalence of virulence factors and detrimental enzymatic activities in 99 Lactic Acid Bacteria (LAB) (59 enterococci and 40 non-enterococci) isolated from aquatic animals regarded as human food. Results These LAB displayed a broad antimicrobial/bacteriocin activity against the main Gram-positive and Gram-negative fish pathogens. However, particular safety concerns based on antibiotic resistance and virulence factors were identified in the genus Enterococcus (86%) (Enterococcus faecalis, 100%; E. faecium, 79%). Antibiotic resistance was also found in the genera Weissella (60%), Pediococcus (44%), Lactobacillus (33%), but not in leuconostocs and lactococci. Antibiotic resistance genes were found in 7.5% of the non-enterococci, including the genera Pediococcus (12.5%) and Weissella (6.7%). One strain of both Pediococcus pentosaceus and Weissella cibaria carried the erythromycin resistance gene mef(A/E), and another two P. pentosaceus strains harboured lnu(A) conferring resistance to lincosamides. Gelatinase activity was found in E. faecalis and E. faecium (71 and 11%, respectively), while a low number of E. faecalis (5%) and none E. faecium exerted hemolytic activity. None enterococci and non-enterococci showed bile deconjugation and mucin degradation abilities, or other detrimental enzymatic activities. Conclusions To our knowledge, this is the first description of mef(A/E) in the genera Pediococcus and Weissella, and lnu(A) in the genus Pediococcus. The in vitro subtractive screening presented in this work constitutes a valuable strategy for the large-scale preliminary selection of putatively safe LAB

  14. Inhibition of Lipid A Biosynthesis as the Primary Mechanism of CHIR-090 Antibiotic Activity in Escherichia coli

    Science.gov (United States)

    Barb, Adam W.; McClerren, Amanda L.; Snehelatha, Karnem; Reynolds, C. Michael; Zhou, Pei; Raetz, Christian R.H.

    2009-01-01

    The deacetylation of UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine (UDP-3-O-acyl-GlcNAc) by LpxC is the committed reaction of lipid A biosynthesis. CHIR-090, a novel N-aroyl-l-threonine hydroxamic acid, is a potent, slow, tight-binding inhibitor of the LpxC deacetylase from the hyperthermophile Aquifex aeolicus, and it has excellent antibiotic activity against P. aeruginosa and E. coli, as judged by disk diffusion assays. We now report that CHIR-090 is also a two-step slow, tight-binding inhibitor of Escherichia coli LpxC with Ki = 4.0 nM, Ki* = 0.5 nM, k5 = 1.9 min-1 and k6 = 0.18 min-1. CHIR-090 at low nM levels inhibits LpxC orthologues from diverse Gram-negative pathogens, including Pseudomonas aeruginosa, Neisseria meningitidis, and Helicobacter pylori. In contrast, CHIR-090 is a relatively weak competitive and conventional inhibitor (lacking slow, tight-binding kinetics) of LpxC from Rhizobium leguminosarum (Ki = 340 nM), a Gram-negative plant endosymbiont that is resistant to this compound. The KM (4.8 μM) and the kcat (1.7 s-1) of R. leguminosarum LpxC with UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine as the substrate are similar to values reported for E. coli LpxC. R. leguminosarum LpxC therefore provides a useful control for validating LpxC as the primary target of CHIR-090 in vivo. An E. coli construct in which the chromosomal lpxC gene is replaced by R. leguminosarum lpxC is resistant to CHIR-090 up to 100 μg/mL, or 400 times above the minimal inhibitory concentration for wild-type E. coli. Given its relatively broad spectrum and potency against diverse Gram-negative pathogens, CHIR-090 is an excellent lead for the further development of new antibiotics targeting the lipid A pathway. PMID:17335290

  15. Determination of four fluoroquinolone antibiotics in tap water in Guangzhou and Macao

    International Nuclear Information System (INIS)

    Yiruhan; Wang Qiaojun; Mo Cehui; Li Yanwen; Gao Peng; Tai Yiping; Zhang Yan; Ruan Zhili; Xu Jiawei

    2010-01-01

    Four fluoroquinolone antibiotics (norfloxacin, ciprofloxacin, lomefloxacin, and enrofloxacin) in tap water in Guangzhou and Macao were analyzed using high performance liquid chromatography fluorescence detection. The results showed that all target antibiotics were detected in high rate both in Guangzhou (77.5%) and Macao (100%), ranging from 1.0 to 679.7 ng/L (SD ≤ 37.6) in Guangzhou, and from 2.0 to 37.0 ng/L (SD ≤ 2.5) in Macao. The fluoroquinolone antibiotics pollution in tap water widely distributes in Guangzhou and Macao. In addition, the effect of rainfall on concentration of fluoroquinolone antibiotics in south China was also investigated. Our result indicates that the antibiotic concentration in tap water in Guangzhou tends to obviously reduce at the beginning of rainy season, even decreases below the limit of quantification immediately. Thus, it was clarified that the heavy rain in south China has the function of reducing the fluoroquinolone antibiotics concentrations in tap water. - The antibiotics were detected in the tap water in Guangzhou and Macao using our developed method for fluoresence detection with high performance liquid chromatography

  16. Determination of four fluoroquinolone antibiotics in tap water in Guangzhou and Macao

    Energy Technology Data Exchange (ETDEWEB)

    Yiruhan; Wang Qiaojun [Department of Environmental Engineering, Jinan University, Huangpudadaoxi 601, Guangzhou 510632 (China); Mo Cehui, E-mail: tchmo@jnu.edu.c [Department of Environmental Engineering, Jinan University, Huangpudadaoxi 601, Guangzhou 510632 (China); Li Yanwen; Gao Peng; Tai Yiping; Zhang Yan; Ruan Zhili; Xu Jiawei [Department of Environmental Engineering, Jinan University, Huangpudadaoxi 601, Guangzhou 510632 (China)

    2010-07-15

    Four fluoroquinolone antibiotics (norfloxacin, ciprofloxacin, lomefloxacin, and enrofloxacin) in tap water in Guangzhou and Macao were analyzed using high performance liquid chromatography fluorescence detection. The results showed that all target antibiotics were detected in high rate both in Guangzhou (77.5%) and Macao (100%), ranging from 1.0 to 679.7 ng/L (SD {<=} 37.6) in Guangzhou, and from 2.0 to 37.0 ng/L (SD {<=} 2.5) in Macao. The fluoroquinolone antibiotics pollution in tap water widely distributes in Guangzhou and Macao. In addition, the effect of rainfall on concentration of fluoroquinolone antibiotics in south China was also investigated. Our result indicates that the antibiotic concentration in tap water in Guangzhou tends to obviously reduce at the beginning of rainy season, even decreases below the limit of quantification immediately. Thus, it was clarified that the heavy rain in south China has the function of reducing the fluoroquinolone antibiotics concentrations in tap water. - The antibiotics were detected in the tap water in Guangzhou and Macao using our developed method for fluoresence detection with high performance liquid chromatography

  17. Occurrence and distribution of antibiotics in urban soil in Beijing and Shanghai, China.

    Science.gov (United States)

    Gao, Lihong; Shi, Yali; Li, Wenhui; Liu, Jiemin; Cai, Yaqi

    2015-08-01

    The recycling of reclaimed wastewater for irrigation and road cleaning is an important strategy to minimize water scarcity in megacities. However, little is known regarding the potential accumulation of antibiotics contained in reclaimed wastewater in urban soil. We investigated the occurrence and distribution of eight quinolones (QNs), nine sulfonamides (SAs), and five macrolides (MLs) antibiotics in urban surface soil in Beijing and Shanghai, China. QNs, especially norfloxacin (NOR), ofloxacin (OFL), and ciprofloxacin (CIP) were the predominant antibiotics in urban surface soil, and NOR revealed the highest average concentration of 94.6 μg kg(-1). The antibiotic concentrations in urban soil in our study were higher than those detected in agricultural soils after long-term wastewater irrigation and manure fertilization. The concentrations of antibiotics in Shanghai urban soil showed a significant negative correlation with soil pH and a positive correlation with total organic carbon (TOC), reflecting the effect of speciation and soil organic matter content on sorption and retention. In addition, antibiotic concentrations in the urban soil were positively correlated with heavy metal contents, likely due to their coexistence in reclaimed wastewater and the promoting effect of metals on the sorption of antibiotics. In several soil samples, NOR, OFL, CIP, enrofloxacin (ENR), and fleroxacin (FLE) showed higher concentrations than the trigger value of 100 μg kg(-1) in soil, indicating a potential risk for the environment.

  18. Occurrence, removal, and risk assessment of antibiotics in 12 wastewater treatment plants from Dalian, China.

    Science.gov (United States)

    Zhang, Xin; Zhao, Hongxia; Du, Juan; Qu, Yixuan; Shen, Chen; Tan, Feng; Chen, Jingwen; Quan, Xie

    2017-07-01

    In this study, the occurrence and removal efficiencies of 31 antibiotics, including 11 sulfonamides (SAs), five fluoroquinolones (FQs), four macrolides (MLs), four tetracyclines (TCs), three chloramphenicols (CAPs), and four other antibiotics (Others), were investigated in 12 municipal wastewater treatment plants (WWTPs) in Dalian, China. A total of 29 antibiotics were detected in wastewater samples with the concentration ranging from 63.6 to 5404.6 ng/L. FQs and SAs were the most abundant antibiotic classes in most wastewater samples, accounting for 42.2 and 23.9% of total antibiotic concentrations, respectively, followed by TCs (16.0%) and MLs (14.8%). Sulfamethoxazole, erythromycin, clarithromycin, azithromycin, ofloxacin, and norfloxacin were the most frequently detected antibiotics; of these, the concentration of ofloxacin was the highest in most of influent (average concentration = 609.8 ng/L) and effluent (average concentration = 253.4 ng/L) samples. The removal efficiencies varied among WWTPs in the range of -189.9% (clarithromycin) to 100% (enoxacin, doxycycline, etc), and more than 50% of antibiotics could not be efficiently removed with the removal efficiency less than 65%. An environmental risk assessment was also performed in the WWTP effluents by calculating the risk quotient (RQ), and high RQ values (>1) indicated erythromycin and clarithromycin might cause the ecological risk on organisms in surrounding water near discharge point of WWTPs in this area, which warrants further attention.

  19. Combating Antibiotic Resistance

    Science.gov (United States)

    ... Bacteria Phasing Out Certain Antibiotic Use in Farm Animals FDA: Cutting-Edge Technology Sheds Light on Antibiotic Resistance For More Information Antibiotics and Antibiotic Resistance Antimicrobial Resistance Information for Consumers and Health Professionals CDC: ...

  20. Prevalence, species differentiation, haemolytic activity, and antibiotic susceptibility of aeromonads in untreated well water

    Directory of Open Access Journals (Sweden)

    Khalifa Sifaw Ghenghesh

    2001-02-01

    Full Text Available The use of untreated water for drinking and other activities have been associated with intestinal and extraintestinal infections in humans due to Aeromonas species. In the present study aeromonads were isolated from 48.7% of 1,000 water samples obtained from wells and other miscellaneous sources. Aeromonas species were detected in 45% of samples tested in spring, 34.5% in summer, 48% in autumn and 60% of samples tested in winter. Speciation of 382 strains resulted in 225 (59% being A. hydrophila, 103 (27% A. caviae, 42 (11% A. sobria and 11 (3% atypical aeromonads. Of 171 Aeromonas strains tested for their haemolytic activity, 53%, 49%, 40% and 37% were positive in this assay using human, horse, sheep and camel erythrocytes respectively. The results obtained indicate that potentially enteropathogenic Aeromonas species are commonly present in untreated drinking water obtained from wells in Libya (this may also apply to other neighbouring countries which may pose a health problem to users of such water supplies. In addition, ceftriaxone and ciprofloxacin are suitable drugs that can be used in the treatment of Aeromonas-associated infections, particularly in the immunocompromised, resulting from contact with untreated sources of water.

  1. Spectroscopic, semiempirical studies and antibacterial activity of new urethane derivatives of natural polyether antibiotic - Monensin A

    Science.gov (United States)

    Huczyński, Adam; Stefańska, Joanna; Piśmienny, Mieszko; Brzezinski, Bogumil

    2013-02-01

    A series of new Monensin A dimers linked by diurethane moiety were synthesised and their molecular structures were studied using ESI-MS, FT-IR, 1H and 13C NMR and PM5 methods. The results showed that the compounds form a pseudo-cyclic structure stabilized by three intramolecular hydrogen bonds and the sodium cation was coordinated by five oxygen atoms of polyether skeleton of Monensin moiety. The NMR and FT-IR data of complexes of Monensin urethane sodium salts demonstrated that within the pseudo-cyclic structure the carbonyl oxygen atom of the urethane group did not coordinate the sodium cation. Monensin urethanes were tested in vitro for the activity against Gram-positive and Gram-negative bacteria and fungi as well as against a series of clinical isolates of Staphylococcus: methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA). The most active compound against MRSA and MSSA was 1,4-phenylene diurethane of Monensin with MIC 10.4-41.4 μmol/L).

  2. Antibiotics for acute bronchitis.

    Science.gov (United States)

    Smith, Susan M; Fahey, Tom; Smucny, John; Becker, Lorne A

    2017-06-19

    with 891 participants, RR 0.61, 95% CI 0.48 to 0.79; NNTB 11) and were less likely to have an abnormal lung exam (5 studies with 613 participants, RR 0.54, 95% CI 0.41 to 0.70; NNTB 6). Antibiotic-treated participants also had a reduction in days feeling ill (5 studies with 809 participants, MD -0.64 days, 95% CI -1.16 to -0.13) and days with impaired activity (6 studies with 767 participants, MD -0.49 days, 95% CI -0.94 to -0.04). The differences in proportions with activity limitations at follow-up did not reach statistical significance. There was a significant trend towards an increase in adverse effects in the antibiotic group (12 studies with 3496 participants, RR 1.20, 95% CI 1.05 to 1.36; NNT for an additional harmful outcome 24). There is limited evidence of clinical benefit to support the use of antibiotics in acute bronchitis. Antibiotics may have a modest beneficial effect in some patients such as frail, elderly people with multimorbidity who may not have been included in trials to date. However, the magnitude of this benefit needs to be considered in the broader context of potential side effects, medicalisation for a self limiting condition, increased resistance to respiratory pathogens, and cost of antibiotic treatment.

  3. Co-immobilization of active antibiotics and cell adhesion peptides on calcium based biomaterials.

    Science.gov (United States)

    Palchesko, Rachelle N; Buckholtz, Gavin A; Romeo, Jared D; Gawalt, Ellen S

    2014-07-01

    Two bioactive molecules with unrelated functions, vancomycin and a cell adhesion peptide, were immobilized on the surface of a potential bone scaffold material, calcium aluminum oxide. In order to accomplish immobilization and retain bioactivity three sequential surface functionalization strategies were compared: 1.) vancomycin was chemically immobilized before a cell adhesion peptide (KRSR), 2.) vancomycin was chemically immobilized after KRSR and 3.) vancomycin was adsorbed after binding the cell adhesion peptide. Both molecules remained on the surface and active using all three reaction sequences and after autoclave sterilization based on osteoblast attachment, bacterial turbidity and bacterial zone inhibition test results. However, the second strategy was superior at enhancing osteoblast attachment and significantly decreasing bacterial growth when compared to the other sequences. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Metabolic products of microorganisms. 170. On the antibiotic activity of cladosporin.

    Science.gov (United States)

    Anke, H; Zähner, H

    1978-03-01

    Cladosporin was isolated from the cultures of three species of the genus Eurotium. Cladosporin inhibited the growth of several fungi and at very low concentrations the growth of Bacillus brevis and Clostridium pasteurianum. Bacillus subtilis and most other Gram-positive bacteria were not sensitive. Gram-negative bacteria and yeasts were not affected by concentrations up to 100 microgram/ml. Dimethyl cladosporin showed only week activity against Bacillus brevis with the minimal inhibitory concentrations being a 100 times higher than of cladosporin. The incorporation of leucine and uracil into acid insoluble material in Bacillus brevis cells was completely inhibited by concentration of 0.5 microgram/ml cladosporin. The incorporation of thymidine was not affected at this concentration.

  5. In vitro comparison of the activity of various antibiotics and drugs against new Taiwan isolates and standard strains of avian mycoplasma.

    Science.gov (United States)

    Lin, M Y

    1987-01-01

    Twenty-nine antibiotics or drugs were incorporated individually into mycoplasma agar to evaluate their inhibitory activity against avian mycoplasmas: 100 recent Taiwan isolates of 7 serotypes and 10 standard strains of 7 serotypes were tested. All of the standard strains were very sensitive to erythromycin, chlorotetracycline, doxycycline, minocycline, and tetracycline, but the local isolates were highly resistant to these antibiotics. The drugs or antibiotics that possessed an MIC90 of 50 micrograms/ml or less against the local isolates were tiamulin (less than 0.4 micrograms/ml), lincospectin (2.7), josamycin (2.7), lincomycin (3.0), spectinomycin (4.8), tylosin (6.0), kanamycin (6.0), chloramphenicol (6.0), gentamicin (7.5), apramycin (24.5), doxycycline (27.4), minocycline (29.0), spiramycin (30.0), colistin (44.3), leucomycin (45.0), and streptomycin (50.0). The MIC90 of the other antibiotics or drugs was greater than 50 micrograms/ml. None of the isolates or strains were sensitive to nalidixic acid, ronidazole, penicillin, ampicillin, cephalexin, carbadox, or four sulfa drugs at a concentration about 5 times the therapeutic level.

  6. Characterization of microbial community and antibiotic resistance genes in activated sludge under tetracycline and sulfamethoxazole selection pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ma, Haijun; Ren, Hongqiang; Xu, Ke; Ding, Lili

    2016-11-15

    To investigate the microbial community characteristics, antibiotic resistance genes (ARGs), and bioreactor effluent quality change under tetracycline (TC) and sulfamethoxazole (SMX) selection pressure, sequencing batch reactors (SBRs) were used with environmentally relevant concentration and high-level of TC and SMX concentrations (0, 5 ppb, 50 ppb and 10 ppm). Chemical oxygen demand (COD) and ammonia nitrogen (NH{sub 4}{sup +}−N) removals appeared unchanged (p > 0.05) with 5 and 50 ppb, but decreased significantly with 10 ppm (p < 0.05). Extracellular polymeric substances (EPS) concentrations increased significantly with increasing TC or SMX concentrations (p < 0.05). High-throughput 16S rRNA gene sequencing results suggested that Proteobacteria, Actinobacteria and Bacteroidetes were the three most abundant phyla in sludge samples. The Actinobacteria percentages increased with increasing TC or SMX concentration, while Proteobacteria and Bacteroidetes decreased. The microbial diversity achieved its maximum at 5 ppb and decreased with higher concentrations. The total ARGs abundances in sludge increased with addition of TC or SMX, and the higher relative abundances were in the order of sul1 > tetG > sul2 > tetA > intI1 > tetS > tetC. Pearson correlation analysis showed most ARGs (tetA, tetC, tetG, tetK, tetM, sul1) were significantly correlated with intI1 (p < 0.01). - Highlights: • COD and NH{sub 4}{sup +}−N removals significantly decrease under 10 ppm TC or SMX. • Activated sludge EPS concentrations increase with increasing TC or SMX concentrations. • TC and SMX affect the microbial community diversity of activated sludge. • Actinobacteria abundances increase with increase of TC or SMX concentration. • ARGs abundance increases with addition of TC or SMX.

  7. Blue light treatment of Pseudomonas aeruginosa: Strong bactericidal activity, synergism with antibiotics and inactivation of virulence factors.

    Science.gov (United States)

    Fila, Grzegorz; Kawiak, Anna; Grinholc, Mariusz Stanislaw

    2017-08-18

    Pseudomonas aeruginosa is among the most common pathogens responsible for both acute and chronic infections of high incidence and severity. Additionally, P. aeruginosa resistance to conventional antimicrobials has increased rapidly over the past decade. Therefore, it is crucial to explore new therapeutic options, particularly options that specifically target the pathogenic mechanisms of this microbe. The ability of a pathogenic bacterium to cause disease is dependent upon the production of agents termed 'virulence factors', and approaches to mitigate these agents have gained increasing attention as new antibacterial strategies. Although blue light irradiation is a promising alternative approach, only limited and preliminary studies have described its effect on virulence factors. The current study aimed to investigate the effects of lethal and sub-lethal doses of blue light treatment (BLT) on P. aeruginosa virulence factors. We analyzed the inhibitory effects of blue light irradiation on the production/activity of several virulence factors. Lethal BLT inhibited the activity of pyocyanin, staphylolysin, pseudolysin and other proteases, but sub-lethal BLT did not affect the production/expression of proteases, phospholipases, and flagella- or type IV pili-associated motility. Moreover, a eukaryotic cytotoxicity test confirmed the decreased toxicity of blue light-treated extracellular P. aeruginosa fractions. Finally, the increased antimicrobial susceptibility of P. aeruginosa treated with sequential doses of sub-lethal BLT was demonstrated with a checkerboard test. Thus, this work provides evidence-based proof of the susceptibility of drug-resistant P. aeruginosa to BLT-mediated killing, accompanied by virulence factor reduction, and describes the synergy between antibiotics and sub-lethal BLT.

  8. Contribution of coated humic acids calculated through their surface coverage on nano iron oxides for ofloxacin and norfloxacin sorption.

    Science.gov (United States)

    Peng, Hongbo; Liang, Ni; Li, Hao; Chen, Fangyuan; Zhang, Di; Pan, Bo; Xing, Baoshan

    2015-09-01

    Sorption of organic contaminants on organo-mineral complexes has been investigated extensively, but the sorption contribution of mineral particles was not properly addressed before calculating KOC, especially for ionic organic contaminants. We measured the surface coverage of a humic acid (HA) on nano iron oxides (n-Fe2O3) in a series of synthesized organo-mineral complexes. The contribution of the coated HA to ofloxacin (OFL) and norfloxacin (NOR) sorption in HA-n-Fe2O3 complexes was over 80% of the total sorption with the surface coverage of 36% and fOC of 1.6%. All the coated HA showed higher sorption to NOR and OFL in comparison to the original HA, suggesting HA fractionation and/or physical re-conformation during organo-mineral complex formation. The decreased KOC with multilayer coating may suggest the importance of site-specific interactions for OFL sorption, while the increased KOC with multilayer coating may suggest the importance of partitioning in hydrophobic region for NOR sorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Antibacterial activity of different types of snake venom from the Viperidae family against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Isabela Nascimento Canhas

    2017-09-01

    Full Text Available Toxins and venoms produced by living organisms have exhibited a variety of biological activities against microorganisms. In this study, we tested seven snake venoms from the family Viperidae for antibacterial activity and the activities of reversal of antibiotic resistance and inhibition of biofilm formation against 22 clinical isolates of Staphylococcus aureus. Bothrops moojeni venom exhibited anti staphylococcal activity with the lowest mean value of minimum inhibitory concentration (MIC. Moreover, reversal of antibiotic resistance was observed for combinations of B. moojeni venom (½ x MIC and norfloxacin or ampicillin (both ½ x MIC for 86.4% and 50% of the isolates, respectively. B. moojeni venom alone at ½ MIC inhibited 90% of biofilm formation, whereas in combination with ciprofloxacin, both at ½ MIC, a reduction on the NorA efflux pump activity was observed. The detection of in vitro mutants colonies of S. aureus resistant to B. moojeni venom was low and they did not survive. A phospholipase A2 was purified from the venom of B. moojeni and displayed anti-staphylococcal activity when tested alone or in combination with ciprofloxacin. The results presented here will contribute to the search for new antimicrobial agents against resistant S. aureus.

  10. Effect of pH on the microstructure of β-Ga2O3 and its enhanced photocatalytic activity for antibiotic degradation.

    Science.gov (United States)

    Liu, Jin; Lu, Wei; Zhong, Qian; Wu, Hongzhang; Li, Yunlin; Li, Lili; Wang, Zhenling

    2018-06-01

    Semiconductor photocatalysis has become the focus of recent research on antibiotic treatment because it is a green and efficient technology. In this study, α-GaOOH with several novel microstructures has been synthesized at a low temperature and its subsequent thermal transformation. The influence of pH on the synthesis of α-GaOOH is studied, and the results indicate that pH played an important role in the microstructures of α-GaOOH and β-Ga 2 O 3 . All Ga 2 O 3 samples possess macro-mesoporous network structures and exhibits a remarkable photocatalytic activity for antibiotic degradation. The photoelectron chemical tests show that the separation efficiency of photogenerated charge carriers of Ga 2 O 3 -7.0 is higher than that of other Ga 2 O 3 . The enhanced photocatalytic activity of Ga 2 O 3 -7.0 is mainly ascribed to its morphology and oxygen vacancy. The active species trapping and photoluminescence measurement experiments indicate that OH and O 2 - are the major active species contributing to the photocatalytic process. This study will bring about the potential application in treatment of the antibiotic pollutants. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Antimicrobial Activity and Stability of Short and Long Based Arachnid Synthetic Peptides in the Presence of Commercial Antibiotics

    Directory of Open Access Journals (Sweden)

    Ivan Arenas

    2016-02-01

    Full Text Available Four antimicrobial peptides (AMPs named Pin2[G], Pin2[14], P18K and FA1 were chemically synthesized and purified. The four peptides were evaluated in the presence of eight commercial antibiotics against four microorganisms of medical importance: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The commercial antibiotics used were amoxicillin, azithromycin, ceftriaxone, gentamicin, levofloxacin, sulfamethoxazole, trimethoprim and vancomycin. The best AMP against P. aeruginosa was the peptide FA1, and the best AMP against S. aureus was Pin2[G]. Both FA1 and Pin2[G] were efficient against E. coli, but they were not effective against K. pneumoniae. As K. pneumoniae was resistant to most of the commercial antibiotics, combinations of the AMPs FA1 and Pin2[G] were prepared with these antibiotics. According to the fractional inhibitory concentration (FIC index, the best antimicrobial combinations were obtained with concomitant applications of mixtures of FA1 with levofloxacin and sulfamethoxazole. However, combinations of FA1 or Pin2[G] with other antibiotics showed that total inhibitory effect of the combinations were greater than the sum of the individual effects of either the antimicrobial peptide or the antibiotic. We also evaluated the stability of the AMPs. The AMP Pin2[G] manifested the best performance in saline buffer, in supernatants of bacterial growth and in human blood plasma. Nevertheless, all AMPs were cleaved using endoproteolytic enzymes. These data show advantages and disadvantages of AMPs for potential clinical treatments of bacterial infections, using them in conjunction with commercial antibiotics.

  12. Profile of antibiotic consumption, sensitivity and resistance in an urban area of Andhra Pradesh, India.

    Science.gov (United States)

    Peripi, Sunita Bhargavi; Thadepalli, Venu Gopala Rao; Khagga, Mukkanti; Tripuraribhatla, Prasanna Krishna; Bharadwaj, Dinesh Kumar

    2012-04-01

    Antibiotics are an important category of drugs in which indiscriminate use can affect the susceptibility patterns among infectious organisms, resulting in antibiotic resistance. Data on antibiotic usage and susceptibility patterns were collected from public and private health centres in Vijayawada, Andhra Pradesh, India, through the use of questionnaires. The data collected were then coded, tabulated, computed and evaluated using statistical analysis. The consumption profile of the different categories of drugs used in public and private hospitals was as follows: nutrition and metabolism products 19.0%; gastrointestinal disorder-related drugs 18.5%; antibiotics 16.8%; anti-pyretics and anti-analgesics 20.6%. These drugs were found to be in high demand. Among the antibiotics, aminoglycosides (amikacin), quinolones (ofloxacin, ciprofloxacin), tetracyclines (doxycycline), penicillin (ampicillin) and sulphonamides (co-trimoxazole) were the most commonly prescribed drugs for antibiotic therapy. 46% of the culture laboratory reports were positive with the following organism profile: Escherichia coli (36%), Klebsiella pneumoniae (16%), Staphylococcus aureus (29%), Enterococcus faecalis (9%) and Pseudomonas aeruginosa (10%). In terms of the sensitivity profile of antibacterials, amikacin (66.9%) was the only antibiotic showing sensitivity patterns, while the majority of antibiotics, such as cotrimoxazole, nalidixic acid, amoxicillin, gentamycin and norfloxacin, had acquired a resistance rate of 55.1%-80.6%. The results of this study suggest that indiscriminate prescription and consumption of new broad-spectrum antibiotics against sensitive organisms results in the development of antimicrobial resistance. Therefore, there is an urgent need to curb the excessive use of antibiotics in local hospitals in order to control the trend of increasing antimicrobial resistance to antibiotics.

  13. Prescribing Antibiotics

    DEFF Research Database (Denmark)

    Pedersen, Inge Kryger; Jepsen, Kim Sune

    2018-01-01

    The medical professions will lose an indispensable tool in clinical practice if even simple infections cannot be cured because antibiotics have lost effectiveness. This article presents results from an exploratory enquiry into “good doctoring” in the case of antibiotic prescribing at a time when...... the knowledge base in the healthcare field is shifting. Drawing on in-depth interviews about diagnosing and prescribing, the article demonstrates how the problem of antimicrobial resistance is understood and engaged with by Danish general practitioners. When general practitioners speak of managing “non......-medical issues,” they refer to routines, clinical expertise, experiences with their patients, and decision-making based more on contextual circumstances than molecular conditions—and on the fact that such conditions can be hard to assess. This article’s contribution to knowledge about how new and global health...

  14. Phytotoxicity of veterinary antibiotics to seed germination and root elongation of crops.

    Science.gov (United States)

    Pan, Min; Chu, L M

    2016-04-01

    Large quantities of veterinary antibiotics (VAs) are being used worldwide in agricultural fields through wastewater irrigation and manure application. They cause damages to the ecosystem when discharged into the environment, but there is a lack of information on their toxicity to plants and animals. This study evaluated the phytotoxic effects of five major VAs, namely tetracycline (TC), sulfamethazine (SMZ), norfloxacin (NOR), erythromycin (ERY) and chloramphenicol (CAP), on seed germination and root elongation in lettuce, tomato, carrot and cucumber, and investigated the relationship between their physicochemical properties and phytotoxicities. Results show that these compounds significantly inhibited root elongation (ptest. TC was associated with the highest level of toxicity, followed by NOR, ERY, SMZ and CAP. Regarding crop species, lettuce was found to be sensitive to most of the VAs. The median effect concentration (EC50) of TC, SMZ, NOR, ERY and CAP to lettuce was 14.4, 157, 49.4, 68.8 and 204 mg/L, respectively. A quantitative structure-activity relationship (QSAR) model has been established based on the measured data. It is evident that hydrophobicity was the most important factor governing the phytotoxicity of these compounds to seeds, which could be explained by the polar narcosis mechanism. Lettuce is considered a good biomarker for VAs in the environment. According to the derived equation, phytotoxicities of selected VA compounds on different crops can be calculated, which could be applicable to other VAs. Environmental risks of VAs were summarized based on the phytotoxicity results and other persistent factors. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Intra- and inter-pandemic variations of antiviral, antibiotics and decongestants in wastewater treatment plants and receiving rivers.

    Directory of Open Access Journals (Sweden)

    Andrew C Singer

    Full Text Available The concentration of eleven antibiotics (trimethoprim, oxytetracycline, ciprofloxacin, azithromycin, cefotaxime, doxycycline, sulfamethoxazole, erythromycin, clarithromycin, ofloxacin, norfloxacin, three decongestants (naphazoline, oxymetazoline, xylometazoline and the antiviral drug oseltamivir's active metabolite, oseltamivir carboxylate (OC, were measured weekly at 21 locations within the River Thames catchment in England during the month of November 2009, the autumnal peak of the influenza A[H1N1]pdm09 pandemic. The aim was to quantify the pharmaceutical response to the pandemic and compare this to drug use during the late pandemic (March 2010 and the inter-pandemic periods (May 2011. A large and small wastewater treatment plant (WWTP were sampled in November 2009 to understand the differential fate of the analytes in the two WWTPs prior to their entry in the receiving river and to estimate drug users using a wastewater epidemiology approach. Mean hourly OC concentrations in the small and large WWTP's influent were 208 and 350 ng/L (max, 2070 and 550 ng/L, respectively. Erythromycin was the most concentrated antibiotic measured in Benson and Oxford WWTPs influent (max=6,870 and 2,930 ng/L, respectively. Napthazoline and oxymetazoline were the most frequently detected and concentrated decongestant in the Benson WWTP influent (1650 and 67 ng/L and effluent (696 and 307 ng/L, respectively, but were below detection in the Oxford WWTP. OC was found in 73% of November 2009's weekly river samples (max=193 ng/L, but only in 5% and 0% of the late- and inter-pandemic river samples, respectively. The mean river concentration of each antibiotic during the pandemic largely fell between 17-74 ng/L, with clarithromycin (max=292 ng/L and erythromycin (max=448 ng/L yielding the highest single measure. In general, the concentration and frequency of detecting antibiotics in the river increased during the pandemic. OC was uniquely well-suited for the wastewater

  16. Effects of light and microbial activity on the degradation of two fluoroquinolone antibiotics in pond water and sediment.

    Science.gov (United States)

    Lin, Juo-Shan; Pan, Hung-Yu; Liu, Shiu-Mei; Lai, Hong-Thih

    2010-07-01

    Enrofloxacin (ENR) and ciprofloxacin (CIP) are two fluoroquinolone (FQ) antibiotics widely used to treat diseases of human beings and cultured animals. These two FQs are usually detected in the effluent of municipal sewage plants and related aquatic environments. The purpose of this study was to understand the fates of ENR and CIP in aquaculture pond water and a sediment slurry in a laboratory-scale experiment. Effects of light and microbial activity on the degradation of these two FQs were investigated. Results indicated that natural irradiation plays a major role in the degradation of ENR and CIP in pond water and the sediment slurry. The 50 % dissipation times (DT(50)) with non-sterile treatment were 0.01 and 18.4 d for ENR, and 0.04 and 17.3 d for CIP in the water and sediment slurry, respectively. On the other hand, the degradation of ENR and CIP under dark conditions was slow or even hindered, and all of their DT(50) values exceeded 100 d. These two FQs degraded faster in the sediment slurry than in pond water under dark conditions. Artificial ultraviolet (UV) and fluorescence light had similar effects on the degradation of ENR in the pond water and sediment slurry. Degradation of CIP was faster with UV than with fluorescence light treatment, while no such difference was found for ENR degradation. CIP was a degradation product of ENR under both light and dark conditions, and DT(50) values for both compounds were shorter in the presence of light. The phenomenon of biodegradation was observed during degradation of CIP in the sediment slurry under natural light.

  17. Distribution and Risk Assessment of Antibiotics in a Typical River in North China Plain.

    Science.gov (United States)

    Li, Qingzhao; Gao, Junxia; Zhang, Qiuling; Liang, Lizhen; Tao, He

    2017-04-01

    We evaluated the occurrence and distribution of 12 antibiotics from the sulfonamide (SAs), fluoroquinolone (FQs) and tetracycline (TCs) groups in the Weihe River, North China. The total antibiotic concentrations in surface water, pore water, and sediment samples ranged from 11.1 to 173.1 ng/L, 5.8 to 103.9 ng/L, and 9.5 to 153.4 μg/kg, respectively. The values of the sediment-water partitioning coefficient in the Weihe River varied widely, from not detected to 943, 2213, and 2405 L/kg for SAs, FQs, and TCs, respectively. The values of the partitioning coefficients between sediment and surface water were generally lower than those between sediment and pore water, which indicated ongoing inputs to the water. The risk assessment showed that there were relatively high ecological risks to aquatic algae in this area from sulfamethoxazole, norfloxacin, tetracycline, ofloxacin, and ciprofloxacin.

  18. The Prehistory of Antibiotic Resistance.

    Science.gov (United States)

    Perry, Julie; Waglechner, Nicholas; Wright, Gerard

    2016-06-01

    Antibiotic resistance is a global problem that is reaching crisis levels. The global collection of resistance genes in clinical and environmental samples is the antibiotic "resistome," and is subject to the selective pressure of human activity. The origin of many modern resistance genes in pathogens is likely environmental bacteria, including antibiotic producing organisms that have existed for millennia. Recent work has uncovered resistance in ancient permafrost, isolated caves, and in human specimens preserved for hundreds of years. Together with bioinformatic analyses on modern-day sequences, these studies predict an ancient origin of resistance that long precedes the use of antibiotics in the clinic. Understanding the history of antibiotic resistance is important in predicting its future evolution. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  19. Self-medication with antibiotics among undergraduate nursing students of a government medical college in Eastern India

    Directory of Open Access Journals (Sweden)

    suvadip biswas

    2015-10-01

    Full Text Available Antibiotics serve very useful therapeutic purpose in eradicating pathogens. Unfortunately excessive and inappropriate use of antibiotics results in antibiotic resistance. The consequences of inappropriate self-medication with antibiotics among healthcare professionals have severe implications which might be legal issues, ethical issues, negative impacts on patient and poor quality of health care delivery. The present study was conducted on self-medication by undergraduate nursing students in a government medical college of West Bengal, India. A pre designed questionnaire was used to collect the relevant information pertaining to the study variables. Among the participants 54.2% had self-medicated in the last six months. The antibiotics most commonly used being metronidazole (67.4%, azithromycin (32.6% and norfloxacin (16.8%. Regarding the source of the antibiotics used for self-medication 41.6% participants went for leftover medicines at home, 34.8% participants obtained the drug from community pharmacies or drug stores. Hospital pharmacies and medicine samples were the source of the drugs for 19.2% and 4.4% participants respectively for this purpose. This study has shown that self-medication with antibiotics is common among undergraduate nursing students. There is a need for a rigorous mass enlightenment campaign to educate the population, including the health care professional about the disadvantages and possible complications of antibiotic self-medication. 

  20. Antibiotic resistance of Clostridium perfringens isolates from broiler chickens in Egypt.

    Science.gov (United States)

    Osman, K M; Elhariri, M

    2013-12-01

    The use of antibiotic feed additives in broiler chickens results in a high prevalence of resistance among their enteric bacteria, with a consequent emergence of antibiotic resistance in zoonotic enteropathogens. Despite growing concerns about the emergence of antibiotic-resistant strains, which show varying prevalences in different geographic regions, little work has been done to investigate this issue in the Middle East. This study provides insight into one of the world's most common and financially crippling poultry diseases, necrotic enteritis caused by Clostridium perfringens. The study was designed to determine the prevalence of antibiotic resistance in C. perfringens isolates from clinical cases of necrotic enteritis in broiler chickens in Egypt. A total of 125 isolates were obtained from broiler flocks in 35 chicken coops on 17 farms and were tested using the disc diffusion method. All 125 isolates were resistant to gentamicin, streptomycin, oxolinic acid, lincomycin, erythromycin and spiramycin. The prevalence of resistance to other antibiotics was also high: rifampicin (34%), chloramphenicol (46%), spectinomycin (50%), tylosin-fosfomycin (52%), ciprofloxacin (58%), norfloxacin (67%), oxytetracycline (71%), flumequine (78%), enrofloxacin (82%), neomycin (93%), colistin (94%), pefloxacin (94%), doxycycline (98%) and trimethoprim-sulfamethoxazole (98%). It is recommended that C. perfringens infections in Egypt should be treated with antibiotics for which resistant isolates are rare at present; namely, amoxicillin, ampicillin, cephradine, fosfomycin and florfenicol.

  1. Temporal variability of antibiotics fluxes in wastewater and contribution from hospitals.

    Directory of Open Access Journals (Sweden)

    Sylvain Coutu

    Full Text Available Significant quantities of antibiotics are used in all parts of the globe to treat diseases with bacterial origins. After ingestion, antibiotics are excreted by the patient and transmitted in due course to the aquatic environment. This study examined temporal fluctuations (monthly time scale in antibiotic sources (ambulatory sales and data from a hospital dispensary for Lausanne, Switzerland. Source variability (i.e., antibiotic consumption, monthly data for 2006-2010 were examined in detail for nine antibiotics--azithromycin, ciprofloxacin, clarithromycin, clindamycin, metronidazole, norfloxacin, ofloxacin, sulfamethoxazole and trimethoprim, from which two main conclusions were reached. First, some substances--azithromycin, clarithromycin, ciprofloxacin--displayed high seasonality in their consumption, with the winter peak being up to three times higher than the summer minimum. This seasonality in consumption resulted in seasonality in Predicted Environmental Concentrations (PECs. In addition, the seasonality in PECs was also influenced by that in the base wastewater flow. Second, the contribution of hospitals to the total load of antibiotics reaching the Lausanne Wastewater Treatment Plant (WTP fluctuated markedly on a monthly time scale, but with no seasonal pattern detected. That is, there was no connection between fluctuations in ambulatory and hospital consumption for the substances investigated.

  2. Antibiotics resistance phenomenon and virulence ability in bacteria from water environment

    Directory of Open Access Journals (Sweden)

    Mohamed I. Azzam

    2017-10-01

    Full Text Available This study aims to determine the impact of five main drains as sources of antibiotics resistant bacteria in River Nile at Rosetta branch, and to generate a baseline data on their virulence ability. Out of 212 bacterial isolates, 39.2% and 60.8% were recovered from drains and Rosetta branch, respectively. Susceptibility of bacteria to different antibiotics showed multiple antibiotics resistances (MAR for the majority of isolates. Meanwhile, sensitivity was mostly directed to ofloxacin and norfloxacin antibiotics. Calculated MAR index values (>0.25 classified area of study as potentially health risk environment. Testing virulence ability of bacteria from drains showed positive results (65%. Contrastively, virulent strains in Rosetta branch were mostly lacking in this study. Concluding remarks justify the strong correlation (r = +0.82 between MAR and virulence of bacteria in polluted aquatic ecosystems, and highlight the potential of drains as reactors for their amplification and dissemination. The study suggests regular monitoring for antibiotics resistance in native bacteria of River Nile, prohibition of unregulated use of antibiotics, and proper management for wastes disposal.

  3. Effects of Copper-based Compounds, Antibiotics and a Plant Activator on Population Sizes and Spread of Clavibacter michiganensis subsp. michiganensis in Greenhouse Tomato Seedlings

    Directory of Open Access Journals (Sweden)

    Svetlana Milijašević

    2009-01-01

    Full Text Available Three copper-based compounds (copper hydroxide, copper oxychloride, copper sulphate, two antibiotics (streptomycin and kasugamycin and a plant activator (ASM significantly reduced population sizes and spread of C. michiganensis subsp. michiganensis among tomatoseedlings in the greenhouse. Streptomycin had the best effect in reducing pathogen population size in all sampling regions. Moreover, this antibiotic completely stopped the spread of C. michiganensis subsp. michiganensis in the region most distant from the inoculumfocus. Copper hydroxide mixed with streptomycin significantly limited the pathogen population, compared with copper hydroxide alone, the other copper-based compounds, ASM and kasugamycin. However, combining streptomycin with copper hydroxide did notcontribute to its greater efficacy against the pathogen population. Copper-based compounds, in general, were less effective in limiting pathogen population sizes than the other treatments in all three sampling regions, primarily copper oxychloride and the combinationof copper hydroxide and mancozeb. Among copper compounds, copper hydroxide was the most prominent in reducing the bacterial population, especially in the region closest to the inoculum focus, while its combination with mancozeb did not improve the effects. Kasugamycin significantly limited pathogen population size, compared to copper bactericides, but it was less effective than the other antibiotic compound, i.e. streptomycin. The plant activator ASM significantly reduced population density, and it was more effectivewhen used three days prior to inoculation than six days before inoculation.

  4. Enhanced photocatalytic degradation of norfloxacin in aqueous Bi2WO6 dispersions containing nonionic surfactant under visible light irradiation

    International Nuclear Information System (INIS)

    Tang, Lin; Wang, Jiajia; Zeng, Guangming; Liu, Yani; Deng, Yaocheng; Zhou, Yaoyu; Tang, Jing; Wang, Jingjing; Guo, Zhi

    2016-01-01

    Highlights: • TX100 strongly enhanced the adsorption and photodegradation of NOF in Bi 2 WO 6 dispersions under visible light irradiation (400–750 nm). • Cu 2+ (10 mM) significantly suppressed the photocatalytic degradation of NOF. • FT-IR demonstrated that the NOF adsorbed on Bi 2 WO 6 was completely degraded. • Three possible photocatalytic degradation pathways of NOF were proposed, according to the HPLC/MS/MS analysis. - Abstract: Photocatalytic degradation is an alternative method to remove pharmaceutical compounds in water, however it is hard to achieve efficient rate because of the poor solubility of pharmaceutical compounds in water. This study investigated the photodegradation of norfloxacin in a nonionic surfactant Triton-X100 (TX100)/Bi 2 WO 6 dispersion under visible light irradiation (400–750 nm). It was found that the degradation of poorly soluble NOF can be strongly enhanced with the addition of TX100. TX100 was adsorbed strongly on Bi 2 WO 6 surface and accelerated NOF photodegradation at the critical micelle concentration (CMC = 0.25 mM). Higher TX100 concentration (>0.25 mM) lowered the degradation rate. In the presence of TX100, the degradation rate reached the maximum value when the pH value was 8.06. FTIR analyses demonstrated that the adsorbed NOF on the catalyst was completely degraded after 2 h irradiation. According to the intermediates identified by HPLC/MS/MS, three possible degradation pathways were proposed to include addition of hydroxyl radical to quinolone ring, elimination of piperazynilic ring in fluoroquinolone molecules, and replacement of F atoms on the aromatic ring by hydroxyl radicals.

  5. Antimicrobial activity of Manuka honey against antibiotic-resistant strains of the cell wall-free bacteria Ureaplasma parvum and Ureaplasma urealyticum.

    Science.gov (United States)

    Hillitt, K L; Jenkins, R E; Spiller, O B; Beeton, M L

    2017-03-01

    The susceptibility of the cell wall-free bacterial pathogens Ureaplasma spp. to Manuka honey was examined. The minimum inhibitory concentration (MIC) of Manuka honey for four Ureaplasma urealyticum and four Ureaplasma parvum isolates was determined. Sensitivity to honey was also compared to clinical isolates with resistance to tetracycline, macrolide and fluoroquinolone antibiotics. Finally step-wise resistance training was utilized in an attempt to induce increased tolerance to honey. The MIC was dependent on the initial bacterial load with 7·5 and 18·0% w/v honey required to inhibit U. urealyticum at 1 and 10 6 colour changing units (CCU), respectively, and 4·8 and 15·3% w/v required to inhibit U. parvum at 1 and 10 6  CCU respectively. MIC values were consistently lower for U. parvum compared with U. urealyticum. Antimicrobial activity was seen against tetracycline-resistant, erythromycin-resistant and ciprofloxacin-resistant isolates at 10 5  CCU. No resistance to honey was observed with 50 consecutive challenges at increasing concentrations of honey. This is the first report of the antimicrobial activity of Manuka honey against a cell wall-free bacterial pathogen. The antimicrobial activity was retained against antibiotic-resistant strains and it was not possible to generate resistant mutants. Manuka honey is known to have a broad spectrum of antimicrobial activity, with the bacterial cell wall being suggested as a predominant site of action. This study has demonstrated that Manuka honey has activity against Ureaplasma spp., a genus of cell wall-free bacteria which are intrinsically resistant to many available antibiotics making treatment inherently difficult. This is the first report of the antimicrobial activity of Manuka honey against a bacterial pathogen, in the absence of a cell well and opens scope for the use of components of Manuka honey as a therapeutic among Ureaplasma infections. © 2016 The Society for Applied Microbiology.

  6. [Anti-amebic effect of polyenic antibiotics].

    Science.gov (United States)

    Liubimova, L K; Ovnanian, K O; Ivanova, L N

    1985-03-01

    All-Union Research technological Institute of Antibiotics and Medical Enzymes, Leningrad. Institute of Epidemiology, Virology and medical parasitology, Ministry of Health of the Armenian SSR. The effect of polyenic antibiotics made in the USSR on development of E. histolytica and E. moshkovski was studied. The following antibiotics were used: levorin and its derivatives, mycoheptin, amphotericin B, amphoglucamine and nystatin. The antibiotics were compared with emetine and metronidazole. Some drugs of the imidazole group were also included into the study. On the whole 15 drugs were tested for their antiamebic activity. All the polyenic antibiotics showed a high antiamebic activity. Levorin and its derivatives were the most active. Their MICs ranged from 0.1 to 5.38 micrograms/ml. The most active of the new imidazoles was 100 times less effective than sodium levorin. The studies show that the polyenic antibiotics have an antiamebic activity and a broad antiprotozoal spectrum.

  7. Impacts of human activities on distribution of sulfate-reducing prokaryotes and antibiotic resistance genes in marine coastal sediments of Hong Kong.

    Science.gov (United States)

    Guo, Feng; Li, Bing; Yang, Ying; Deng, Yu; Qiu, Jian-Wen; Li, Xiangdong; Leung, Kenneth My; Zhang, Tong

    2016-09-01

    Sulfate-reducing prokaryotes (SRPs) and antibiotic resistance genes (ARGs) in sediments could be biomarkers for evaluating the environmental impacts of human activities, although factors governing their distribution are not clear yet. By using metagenomic approach, this study investigated the distributions of SRPs and ARGs in marine sediments collected from 12 different coastal locations of Hong Kong, which exhibited different pollution levels and were classified into two groups based on sediment parameters. Our results showed that relative abundances of major SRP genera to total prokaryotes were consistently lower in the more seriously polluted sediments (P-value human impacts. Moreover, a unimodel distribution pattern for SRPs along with the pollution gradient was observed. Although total ARGs were enriched in sediments from the polluted sites, distribution of single major ARG types could be explained neither by individual sediment parameters nor by corresponding concentration of antibiotics. It supports the hypothesis that the persistence of ARGs in sediments may not need the selection of antibiotics. In summary, our study provided important hints of the niche differentiation of SRPs and behavior of ARGs in marine coastal sediment. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Evaluation of the antibiotic activity and genetic mutation of microorganisms in the effluent treated with the electron-beam from waste-water treatment plant

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Hun; Nam, Ji Hyun; Shin, Ji Hye; Yun, Seo Yeon; Cho, Young Cheol; Oh, Kyoung hee [Chungbuk National University, Cheongju (Korea, Republic of)

    2011-04-15

    In this study, the residual concentrations and activities of antibiotics after UV or gamma-ray treatments were estimated, and the effect of irradiation of UV, gamma-ray, or electron beam was estimated on the survivability and less mutagenic effect on bacteria. The changes of bacterial communities and radiation resistant population in the effluent treated with UV and electron-beam were analyzed. The gamma-ray irradiation was more effective than UV in degradation of antibiotics. The extent of mutagenicity of electron-beam irradiation was less than those of UV or gamma-ray irradiations. The application of election-beam to the wastewater treatment system showed the high efficiency of destroying and removal effects on bacterial cells. The selective increase in population of radiation resistant bacteria was not observed. These results indicate that the application of ionizing radiation to the processes of wastewater treatment system will be suitable than UV irradiation because of its degradability of variable antibiotics, high removal rate of harmful bacteria, less mutagenicity of bacteria, and low selective effect on radiation resistant bacteria

  9. Evaluation of the antibiotic activity and genetic mutation of microorganisms in the effluent treated with the electron-beam from waste-water treatment plant

    International Nuclear Information System (INIS)

    Lee, Dong Hun; Nam, Ji Hyun; Shin, Ji Hye; Yun, Seo Yeon; Cho, Young Cheol; Oh, Kyoung hee

    2011-04-01

    In this study, the residual concentrations and activities of antibiotics after UV or gamma-ray treatments were estimated, and the effect of irradiation of UV, gamma-ray, or electron beam was estimated on the survivability and less mutagenic effect on bacteria. The changes of bacterial communities and radiation resistant population in the effluent treated with UV and electron-beam were analyzed. The gamma-ray irradiation was more effective than UV in degradation of antibiotics. The extent of mutagenicity of electron-beam irradiation was less than those of UV or gamma-ray irradiations. The application of election-beam to the wastewater treatment system showed the high efficiency of destroying and removal effects on bacterial cells. The selective increase in population of radiation resistant bacteria was not observed. These results indicate that the application of ionizing radiation to the processes of wastewater treatment system will be suitable than UV irradiation because of its degradability of variable antibiotics, high removal rate of harmful bacteria, less mutagenicity of bacteria, and low selective effect on radiation resistant bacteria

  10. Validation and Application of a Dried Blood Spot Assay for Biofilm-Active Antibiotics Commonly Used for Treatment of Prosthetic Implant Infections

    Science.gov (United States)

    Knippenberg, Ben; Page-Sharp, Madhu; Clark, Ben; Dyer, John; Batty, Kevin T.; Davis, Timothy M. E.

    2016-01-01

    Dried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic (PK)/pharmacodynamic (PD) studies in situations where venous blood sampling is logistically difficult. We sought to develop, validate, and apply a DBS assay for rifampin (RIF), fusidic acid (FUS), and ciprofloxacin (CIP). These antibiotics are considered active against organisms in biofilms and are therefore commonly used for the treatment of infections associated with prosthetic implants. A liquid chromatography-mass spectroscopy DBS assay was developed and validated, including red cell partitioning and thermal stability for each drug and the rifampin metabolite desacetyl rifampin (Des-RIF). Plasma and DBS concentrations in 10 healthy adults were compared, and the concentration-time profiles were incorporated into population PK models. The limits of quantification for RIF, Des-RIF, CIP, and FUS in DBS were 15 μg/liter, 14 μg/liter, 25 μg/liter, and 153 μg/liter, respectively. Adjusting for hematocrit, red cell partitioning, and relative recovery, DBS-predicted plasma concentrations were comparable to measured plasma concentrations for each antibiotic (r > 0.95; P < 0.0001), and Bland-Altman plots showed no significant bias. The final population PK estimates of clearance, volume of distribution, and time above threshold MICs for measured and DBS-predicted plasma concentrations were comparable. These drugs were stable in DBSs for at least 10 days at room temperature and 1 month at 4°C. The present DBS antibiotic assays are robust and can be used as surrogates for plasma concentrations to provide valid PK and PK/PD data in a variety of clinical situations, including therapeutic drug monitoring or studies of implant infections. PMID:27270283

  11. Synthetic membrane-targeted antibiotics.

    Science.gov (United States)

    Vooturi, S K; Firestine, S M

    2010-01-01

    Antimicrobial resistance continues to evolve and presents serious challenges in the therapy of both nosocomial and community-acquired infections. The rise of resistant strains like methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA) and vancomycin-resistant enterococci (VRE) suggests that antimicrobial resistance is an inevitable evolutionary response to antimicrobial use. This highlights the tremendous need for antibiotics against new bacterial targets. Agents that target the integrity of bacterial membrane are relatively novel in the clinical armamentarium. Daptomycin, a lipopeptide is a classical example of membrane-bound antibiotic. Nature has also utilized this tactic. Antimicrobial peptides (AMPs), which are found in all kingdoms, function primarily by permeabilizing the bacterial membrane. AMPs have several advantages over existing antibiotics including a broad spectrum of activity, rapid bactericidal activity, no cross-resistance with the existing antibiotics and a low probability for developing resistance. Currently, a small number of peptides have been developed for clinical use but therapeutic applications are limited because of poor bioavailability and high manufacturing cost. However, their broad specificity, potent activity and lower probability for resistance have spurred the search for synthetic mimetics of antimicrobial peptides as membrane-active antibiotics. In this review, we will discuss the different classes of synthetic membrane-bound antibiotics published since 2004.

  12. Diurnal variations in the occurrence and the fate of hormones and antibiotics in activated sludge wastewater treatment in Oslo, Norway

    International Nuclear Information System (INIS)

    Plosz, Benedek Gy.; Leknes, Henriette; Liltved, Helge; Thomas, Kevin V.

    2010-01-01

    We present an assessment of the dynamics in the influent concentration of hormones (estrone, estriol) and antibiotics (trimethoprim, sulfamethoxazole, tetracycline, ciprofloxacin) in the liquid phase including the efficiency of biological municipal wastewater treatment. The concentration of estradiol, 17-α-ethinylestradiol, doxycycline, oxytetracycline, demeclocycline, chlortetracycline, cefuroxime, cyclophosphamide, and ifosfamide were below the limit of detection in all of the sewage samples collected within this study. Two different types of diurnal variation pattern were identified in the influent mass loads of selected antibiotics and hormones that effectively correlate with daily drug administration patterns and with the expected maximum human hormone release, respectively. The occurrence of natural hormones and antimicrobials, administered every 12 hours, shows a daily trend of decreasing contaminant mass load, having the maximum values in the morning hours. The occurrence of antibiotics, typically administered every 8 hours, indicates a daily peak value in samples collected under the highest hydraulic loading. The efficiency of biological removal of both hormones and antibiotics is shown to be limited. Compared to the values obtained in the influent samples, increased concentrations are observed in the biologically treated effluent for trimethoprim, sulfamethoxazole and ciprofloxacin, mainly as a result of deconjugation processes. Ciprofloxacin is shown as the predominant antimicrobial compound in the effluent, and it is present at quantities approximately 10 fold greater than the total mass of the other of the compounds due to poor removal efficiency and alternating solid-liquid partitioning behaviour. Our results suggest that, to increase the micro-pollutant removal and the chemical dosing efficiency in enhanced tertiary treatment, significant benefits can be derived from the optimisation of reactor design and the development of control schemes that

  13. Antibacterial activity of three newly-synthesized chalcones & synergism with antibiotics against clinical isolates of methicillin-resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Dragana D Bozic

    2014-01-01

    Interpretation & conclusions: o0 ur study demonstrated that three newly-synthesized chalcones exhibited significant anti-MRSA effect and synergism with non-β-lactam antibiotics. The most effective compound was 1,3-Bis-(2-hydroxy-phenyl-propenone. Our results provide useful information for future research of possible application of chalcones in combination with conventional anti-MRSA therapy as promising new antimicrobial agents.

  14. Antibiotics induce mitonuclear protein imbalance but fail to inhibit respiration and nutrient activation in pancreatic β-cells.

    Science.gov (United States)

    Santo-Domingo, Jaime; Chareyron, Isabelle; Broenimann, Charlotte; Lassueur, Steve; Wiederkehr, Andreas

    2017-08-15

    Chloramphenicol and several other antibiotics targeting bacterial ribosomes inhibit mitochondrial protein translation. Inhibition of mitochondrial protein synthesis leads to mitonuclear protein imbalance and reduced respiratory rates as confirmed here in HeLa and PC12 cells. Unexpectedly, respiration in INS-1E insulinoma cells and primary human islets was unaltered in the presence of chloramphenicol. Resting respiratory rates and glucose stimulated acceleration of respiration were also not lowered when a range of antibiotics including, thiamphenicol, streptomycin, gentamycin and doxycycline known to interfere with bacterial protein synthesis were tested. However, chloramphenicol efficiently reduced mitochondrial protein synthesis in INS-1E cells, lowering expression of the mtDNA encoded COX1 subunit of the respiratory chain but not the nuclear encoded ATP-synthase subunit ATP5A. Despite a marked reduction of the essential respiratory chain subunit COX1, normal respiratory rates were maintained in INS-1E cells. ATP-synthase dependent respiration was even elevated in chloramphenicol treated INS-1E cells. Consistent with these findings, glucose-dependent calcium signaling reflecting metabolism-secretion coupling in beta-cells, was augmented. We conclude that antibiotics targeting mitochondria are able to cause mitonuclear protein imbalance in insulin secreting cells. We hypothesize that in contrast to other cell types, compensatory mechanisms are sufficiently strong to maintain normal respiratory rates and surprisingly even result in augmented ATP-synthase dependent respiration and calcium signaling following glucose stimulation. The result suggests that in insulin secreting cells only lowering COX1 below a threshold level may result in a measurable impairment of respiration. When focusing on mitochondrial function, care should be taken when including antibiotics targeting translation for long-term cell culture as depending on the sensitivity of the cell type analyzed

  15. Diurnal variations in the occurrence and the fate of hormones and antibiotics in activated sludge wastewater treatment in Oslo, Norway

    Energy Technology Data Exchange (ETDEWEB)

    Plosz, Benedek Gy., E-mail: benedek.plosz@niva.no [Norwegian Institute for Water Research, NIVA, Gaustadalleen 21, NO-0349, Oslo (Norway); Leknes, Henriette [Norwegian Institute for Air Research NILU, 2027 Kjeller (Norway); Liltved, Helge; Thomas, Kevin V. [Norwegian Institute for Water Research, NIVA, Gaustadalleen 21, NO-0349, Oslo (Norway)

    2010-03-15

    We present an assessment of the dynamics in the influent concentration of hormones (estrone, estriol) and antibiotics (trimethoprim, sulfamethoxazole, tetracycline, ciprofloxacin) in the liquid phase including the efficiency of biological municipal wastewater treatment. The concentration of estradiol, 17-{alpha}-ethinylestradiol, doxycycline, oxytetracycline, demeclocycline, chlortetracycline, cefuroxime, cyclophosphamide, and ifosfamide were below the limit of detection in all of the sewage samples collected within this study. Two different types of diurnal variation pattern were identified in the influent mass loads of selected antibiotics and hormones that effectively correlate with daily drug administration patterns and with the expected maximum human hormone release, respectively. The occurrence of natural hormones and antimicrobials, administered every 12 hours, shows a daily trend of decreasing contaminant mass load, having the maximum values in the morning hours. The occurrence of antibiotics, typically administered every 8 hours, indicates a daily peak value in samples collected under the highest hydraulic loading. The efficiency of biological removal of both hormones and antibiotics is shown to be limited. Compared to the values obtained in the influent samples, increased concentrations are observed in the biologically treated effluent for trimethoprim, sulfamethoxazole and ciprofloxacin, mainly as a result of deconjugation processes. Ciprofloxacin is shown as the predominant antimicrobial compound in the effluent, and it is present at quantities approximately 10 fold greater than the total mass of the other of the compounds due to poor removal efficiency and alternating solid-liquid partitioning behaviour. Our results suggest that, to increase the micro-pollutant removal and the chemical dosing efficiency in enhanced tertiary treatment, significant benefits can be derived from the optimisation of reactor design and the development of control schemes that

  16. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Hansen, Malene Plejdrup; Hoffmann, Tammy C; McCullough, Amanda R

    2015-01-01

    hygiene, and possibly vaccination and exercise, may be effective. Also, a large range of complementary and alternative medicines (e.g. zinc, vitamin C and probiotics) are proposed for preventing and treating ARIs, but evidence for efficacy is scarce. General practitioners' (GPs) attitudes towards...... wrong. Shared decision making might be a solution, as it enables clinician and patient to participate jointly in making a health decision, having discussed the options together with the evidence for their harms as well as benefits. Furthermore, GPs' diagnostic uncertainty - often leading...... will greatly improve the use of antibiotics for ARIs. However, used in concert, combinations are likely to enable clinicians and health care systems to implement the strategies that will reduce antimicrobial resistance in the future....

  17. Effect of temperature on removal of antibiotic resistance genes by anaerobic digestion of activated sludge revealed by metagenomic approach.

    Science.gov (United States)

    Zhang, Tong; Yang, Ying; Pruden, Amy

    2015-09-01

    As antibiotic resistance continues to spread globally, there is growing interest in the potential to limit the spread of antibiotic resistance genes (ARGs) from wastewater sources. In particular, operational conditions during sludge digestion may serve to discourage selection of resistant bacteria, reduce horizontal transfer of ARGs, and aid in hydrolysis of DNA. This study applied metagenomic analysis to examine the removal efficiency of ARGs through thermophilic and mesophilic anaerobic digestion using bench-scale reactors. Although the relative abundance of various ARGs shifted from influent to effluent sludge, there was no measureable change in the abundance of total ARGs or their diversity in either the thermophilic or mesophilic treatment. Among the 35 major ARG subtypes detected in feed sludge, substantial reductions (removal efficiency >90%) of 8 and 13 ARGs were achieved by thermophilic and mesophilic digestion, respectively. However, resistance genes of aadA, macB, and sul1 were enriched during the thermophilic anaerobic digestion, while resistance genes of erythromycin esterase type I, sul1, and tetM were enriched during the mesophilic anaerobic digestion. Efflux pump remained to be the major antibiotic resistance mechanism in sludge samples, but the portion of ARGs encoding resistance via target modification increased in the anaerobically digested sludge relative to the feed. Metagenomic analysis provided insight into the potential for anaerobic digestion to mitigate a broad array of ARGs.

  18. Antibiotics and inflammatory bowel diseases.

    Science.gov (United States)

    Scribano, Maria Lia; Prantera, Cosimo

    2013-01-01

    Inflammatory bowel diseases are characterized by an altered composition of gut microbiota (dysbiosis) that may contribute to their development. Antibiotics can alter the bacterial flora, and a link between antibiotic use and onset of Crohn's disease (CD), but not ulcerative colitis, has been reported. The hypothesis that Mycobacterium avium subspecies paratuberculosis (MAP) could be an etiologic agent of CD has not been confirmed by a large study on patients treated by an association of antibiotics active against MAP. The observations supporting a role of intestinal microbiota in CD pathogenesis provide the rationale for a therapeutic manipulation of the intestinal flora through the employment of antibiotics. However, current data do not strongly support a therapeutic benefit from antibiotics, and there is still controversy regarding their use as primary therapy for treatment of acute flares of CD, and for postoperative recurrence prevention. Nevertheless, clinical practice and some studies suggest that a subgroup of patients with colonic involvement, early disease, and abnormal laboratory test of inflammation may respond better to antibiotic treatment. Since their long-term use is frequently complicated by a high rate of side effects, the use of antibiotics that work locally appears to be promising.

  19. Seasonal variation of antibiotics concentration in the aquatic environment: a case study at Jianghan Plain, central China.

    Science.gov (United States)

    Yao, Linlin; Wang, Yanxin; Tong, Lei; Li, Yonggang; Deng, Yamin; Guo, Wei; Gan, Yiqun

    2015-09-15

    25 antibiotics (macrolides, tetracyclines, fluoroquinolones and sulfonamides) were detected in swine wastewater, river water, rivulet water and in groundwater samples from multi-level monitoring boreholes (with sampling ports, respectively, at 10, 25 and 50 m below the land surface) at Jianghan Plain, central China. Except swine wastewater, the antibiotic concentrations in groundwater, river and rivulet water were higher in spring than those in winter. Nineteen antibiotics were detected at 100% frequencies in all kinds of water samples. In groundwater, fluoroquinolones and tetracyclines were the predominant antibiotics and the total concentrations of 25 antibiotics commonly decreased with the aquifer depth. Most groundwater samples collected in spring had high concentrations of norfloxacin, with average values of 65.27 ng · L(-1), 37.28 ng · L(-1) and 46.83 ng · L(-1), respectively, at 10, 25 and 50 m deep boreholes. By contrast, the concentrations of sulfamethazine and erythromycin were rather low in groundwater, but high in surface water. Groundwater samples collected from sites close to rivers or rivulets had much higher contents of antibiotics than those from other sites, indicating that the dominant source of antibiotics in groundwater should be the contaminated rivers or rivulets, rather than the scattered pig and poultry farms in the study area. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. LyeTxI-b, a Synthetic Peptide Derived From Lycosa erythrognatha Spider Venom, Shows Potent Antibiotic Activity in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Pablo V. M. Reis

    2018-04-01

    Full Text Available The antimicrobial peptide LyeTxI isolated from the venom of the spider Lycosa erythrognatha is a potential model to develop new antibiotics against bacteria and fungi. In this work, we studied a peptide derived from LyeTxI, named LyeTxI-b, and characterized its structural profile and its in vitro and in vivo antimicrobial activities. Compared to LyeTxI, LyeTxI-b has an acetylated N-terminal and a deletion of a His residue, as structural modifications. The secondary structure of LyeTxI-b is a well-defined helical segment, from the second amino acid to the amidated C-terminal, with no clear partition between hydrophobic and hydrophilic faces. Moreover, LyeTxI-b shows a potent antimicrobial activity against Gram-positive and Gram-negative planktonic bacteria, being 10-fold more active than the native peptide against Escherichia coli. LyeTxI-b was also active in an in vivo model of septic arthritis, reducing the number of bacteria load, the migration of immune cells, the level of IL-1β cytokine and CXCL1 chemokine, as well as preventing cartilage damage. Our results show that LyeTxI-b is a potential therapeutic model for the development of new antibiotics against Gram-positive and Gram-negative bacteria.

  1. Antimicrobial activity and synergy of antibiotics with two biphenyl compounds, protosappanins A and B from Sappan Lignum against methicillin-resistant Staphylococcus aureus strains.

    Science.gov (United States)

    Zuo, Guo-Ying; Han, Zong-Qi; Han, Jun; Hao, Xiao-Yan; Tang, Hua-Shu; Wang, Gen-Chun

    2015-10-01

    This study aims to investigate antimicrobial ingredients from Sappan Lignum and to evaluate their synergy on methicillin-resistant Staphylococcus aureus strains with antibiotics. Bioactivity-guided phytochemical procedures were used to screen the active compounds. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were assayed by broth microdilution. The synergy was evaluated through checkerboard microdilution and loss of viability assays. Protosappanins A (PsA) and B (PsB) were identified from Sappan Lignum extracts. They showed active against both S. aureus and MRSA with MIC or MIC50 at 64 (PsA) and 128 (PsB) mg/L alone. When they were used in combination with antibiotics, they showed best synergy with amikacin and gentamicin with MIC50 (mg/L) of amikacin reduced more significantly from 32 to four (with PsA) and eight (with PsB), and the fractional inhibitory concentration index (FICI) ranged between 0.078 and 0.500 (FICI50  = 0.375). Moreover, the resistance of MRSA towards amikacin and gentamicin could be reversed by the Clinical and Laboratory Standards Institute criteria. The combined bactericidal mode could as well be synergy. PsA and PsB showed very low cytotoxicity in comparison with their promising activity against MRSA. Protosappanins A and B showed both alone activities and resistance reversal effects of amikacin and gentamicin against MRSA, which warrant further investigations for potential combinatory therapy of MRSA infection. © 2015 Royal Pharmaceutical Society.

  2. Antibacterial and antibiotic resistance modifying activity of the extracts from Allanblackia gabonensis, Combretum molle and Gladiolus quartinianus against Gram-negative bacteria including multi-drug resistant phenotypes.

    Science.gov (United States)

    Fankam, Aimé G; Kuiate, Jules R; Kuete, Victor

    2015-06-30

    Bacterial resistance to antibiotics is becoming a serious problem worldwide. The discovery of new and effective antimicrobials and/or resistance modulators is necessary to tackle the spread of resistance or to reverse the multi-drug resistance. We investigated the antibacterial and antibiotic-resistance modifying activities of the methanol extracts from Allanblackia gabonensis, Gladiolus quartinianus and Combretum molle against 29 Gram-negative bacteria including multi-drug resistant (MDR) phenotypes. The broth microdilution method was used to determine the minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of the samples meanwhile the standard phytochemical methods were used for the preliminary phytochemical screening of the plant extracts. Phytochemical analysis showed the presence of alkaloids, flavonoids, phenols and tannins in all studied extracts. Other chemical classes of secondary metabolites were selectively presents. Extracts from A. gabonensis and C. molle displayed a broad spectrum of activity with MICs varying from 16 to 1024 μg/mL against about 72.41% of the tested bacteria. The extract from the fruits of A. gabonensis had the best activity, with MIC values below 100 μg/mL on 37.9% of tested bacteria. Percentages of antibiotic-modulating effects ranging from 67 to 100% were observed against tested MDR bacteria when combining the leaves extract from C. molle (at MIC/2 and MIC/4) with chloramphenicol, kanamycin, streptomycin and tetracycline. The overall results of the present study provide information for the possible use of the studied plant, especially Allanblackia gabonensis and Combretum molle in the control of Gram-negative bacterial infections including MDR species as antibacterials as well as resistance modulators.

  3. COUPLING OF MEMBRANE BIOREACTOR AND OZONATION FOR REMOVAL OF ANTIBIOTICS FROM HOSPITAL WASTEWATER

    Directory of Open Access Journals (Sweden)

    Bui Xuan Thanh

    2016-02-01

    Full Text Available Antibiotic residues in the environment and their potential toxic effects have been considered as one of the emerging research area in the environmental field. Their continuous introduction in our environment may increase their negative impacts on human health.  In this study, the eliminations of antibiotic such as Norfloxacin (NOR, Ciprofloxacin (CIP, Ofloxacin (OFL and Sulfamethoxazole (SMZ in wastewater of hospital were processed by membrane bioreactor (MBR coupled with ozonation process. In particular, the MBR was applied for the antibiotic removals followed by ozonation process as a post-treatment stage to create an adequate integration to enhance removal efficiency. Achieved results after MBR treatment showed that the removal efficiency of NOR, CIP, OFL and SMZ were 90 ± 4.0% , 83 ± 13% , 81 ± 13 % and  39 ± 6%, respectivley. In addition, those antibiotic matters were continously removed by ozonation process with the removal efficiency of 87±9.0% , 83±1.0% , 81±2.3% and 66±2.3% for NOR, CIP, OFL and SMZ, respectively. In summary, antibiotics could be basically limited by the combination of MBR and ozonation before discharging in aquatic environment.

  4. Spatial and seasonal distribution of selected antibiotics in surface waters of the Pearl Rivers, China.

    Science.gov (United States)

    Yang, Ji-Feng; Ying, Guang-Guo; Zhao, Jian-Liang; Tao, Ran; Su, Hao-Chang; Liu, You-Sheng

    2011-01-01

    The distribution and occurrence of 15 antibiotics in surface water of the Pearl River System (Liuxi River, Shijing River and Zhujiang River) and effluents of four wastewater treatment plants (WWTPs) were investigated in two sampling events representing wet season and dry season by using rapid resolution liquid chromatography-electrospray tandem mass spectrometry (RRLC-MS/MS) in positive ionization mode. Only eight antibiotics (sulfadiazine, sulfapyridine, sulfamethazine, sulfamethoxazole, trimethoprim, roxithromycin, erythromycin-H₂O and norfloxacin) were detected in the water samples of the three rivers and the effluents. The detection frequencies and levels of antibiotics in the dry season were higher than those in the wet season. This could be attributed to the dilution effects in the wet season and relatively lower temperature in the dry season under which antibiotics could persist for a longer period. The levels of the detected antibiotics in different sites are generally in a decreasing order as follows: Shijing River ≥WWTP effluent ≥Zhujiang River ≥ Liuxi River. Risk assessment based on the calculated risk quotients showed that only erythromycin-H₂O and roxithromycin detected in the Pearl Rivers might have adverse effects on aquatic organisms.

  5. Occurrence of veterinary antibiotics and progesterone in broiler manure and agricultural soil in Malaysia.

    Science.gov (United States)

    Ho, Yu Bin; Zakaria, Mohamad Pauzi; Latif, Puziah Abdul; Saari, Nazamid

    2014-08-01

    Repeated applications of animal manure as fertilizer are normal agricultural practices that may release veterinary antibiotics and hormones into the environment from treated animals. Broiler manure samples and their respective manure-amended agricultural soil samples were collected in selected locations in the states of Selangor, Negeri Sembilan and Melaka in Malaysia to identify and quantify veterinary antibiotic and hormone residues in the environment. The samples were analyzed using ultrasonic extraction followed by solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The broiler manure samples were found to be contaminated with at least six target analytes, namely, doxycycline, enrofloxacin, flumequine, norfloxacin, trimethoprim and tylosin. These analytes were detected in broiler manure samples with maximum concentrations reaching up to 78,516 μg kg(-1) dry weight (DW) (doxycycline). For manure-amended agricultural soil samples, doxycycline and enrofloxacin residues were detected in every soil sample. The maximum concentration of antibiotic detected in soil was 1331 μg kg(-1) DW (flumequine). The occurrence of antibiotics and hormones in animal manure at high concentration poses a risk of contaminating agricultural soil via fertilization with animal manure. Some physico-chemical parameters such as pH, total organic carbon (TOC) and metal content played a considerable role in the fate of the target veterinary antibiotics and progesterone in the environment. It was suggested that these parameters can affect the adsorption of pharmaceuticals to solid environmental matrices. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Fate of antibiotics from hospital and domestic sources in a sewage network.

    Science.gov (United States)

    Dinh, QuocTuc; Moreau-Guigon, Elodie; Labadie, Pierre; Alliot, Fabrice; Teil, Marie-Jeanne; Blanchard, Martine; Eurin, Joelle; Chevreuil, Marc

    2017-01-01

    Investigation of domestic and hospital effluents in a sewage system of an elementary watershed showed that antibiotics belonging to eight classes were present with concentrations ranging from antibiotics used in veterinary and human medicine, fourteen were quantified in both the wastewater treatment plant (WWTP) input and output: erythromycin, amoxicillin, tetracycline, trimethoprim, ormethoprim, sulfamethoxazole, vancomycin and seven quinolones (flumequine, enrofloxacin, enoxacin, ofloxacin, lomefloxacin, norfloxacin and ciprofloxacin). Antibiotic concentrations in the hospital effluent (from 0.04 to 17.9μgL -1 ) were ten times higher than those measured in the domestic effluent (from 0.03 to 1.75μgL -1 ), contributing to 90% of the antibiotic inputs to the WWTP. Some molecules such as sulfamethoxazole, erythromycin and trimethoprim displayed higher concentrations after wastewater treatment due to deconjugation of their metabolites, which restores the parent molecules. For other compounds, the antibiotic elimination showed discrepancies depending on their physicochemical properties. For fluoroquinolones, the apparent removal processes were mainly based on adsorption mechanisms, followed by settling, leading to sludge contamination (from 13 to 18,800μgkg -1 dry weight). Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Urinary Escherichia coli antimicrobial susceptibility profiles and their relationship with community antibiotic use in Tasmania, Australia.

    Science.gov (United States)

    Meumann, Ella M; Mitchell, Brett G; McGregor, Alistair; McBryde, Emma; Cooley, Louise

    2015-10-01

    This study assessed urinary Escherichia coli antibiotic susceptibility patterns in Tasmania, Australia, and examined their association with community antibiotic use. The susceptibility profiles of all urinary E. coli isolates collected in Tasmania between January 2010 and December 2012 were included. The amount of Pharmaceutical Benefits Scheme (PBS)-subsidised use of amoxicillin, amoxicillin/clavulanic acid (AMC), cefalexin, norfloxacin, ciprofloxacin and trimethoprim was retrieved (at the Tasmanian population level) and the number of defined daily doses per 1000 population per day in Tasmania for these antibiotics was calculated for each month during the study period. Antimicrobial susceptibility data were assessed for changes over time in the 3-year study period. Antimicrobial use and susceptibility data were assessed for seasonal differences and lag in resistance following antibiotic use. Excluding duplicates, 28145 E. coli isolates were included. Resistance levels were low; 35% of isolates were non-susceptible to amoxicillin, 14% were non-susceptible to trimethoprim and antibiotics for treatment of respiratory tract infections in winter. Quinolone use is restricted by the PBS in Australia, which is the likely explanation for the low levels of quinolone use and resistance identified. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  8. Surveillance of antibiotic resistance

    Science.gov (United States)

    Johnson, Alan P.

    2015-01-01

    Surveillance involves the collection and analysis of data for the detection and monitoring of threats to public health. Surveillance should also inform as to the epidemiology of the threat and its burden in the population. A further key component of surveillance is the timely feedback of data to stakeholders with a view to generating action aimed at reducing or preventing the public health threat being monitored. Surveillance of antibiotic resistance involves the collection of antibiotic susceptibility test results undertaken by microbiology laboratories on bacteria isolated from clinical samples sent for investigation. Correlation of these data with demographic and clinical data for the patient populations from whom the pathogens were isolated gives insight into the underlying epidemiology and facilitates the formulation of rational interventions aimed at reducing the burden of resistance. This article describes a range of surveillance activities that have been undertaken in the UK over a number of years, together with current interventions being implemented. These activities are not only of national importance but form part of the international response to the global threat posed by antibiotic resistance. PMID:25918439

  9. Evaluating the effects of activated carbon on methane generation and the fate of antibiotic resistant genes and class I integrons during anaerobic digestion of solid organic wastes.

    Science.gov (United States)

    Zhang, Jingxin; Mao, Feijian; Loh, Kai-Chee; Gin, Karina Yew-Hoong; Dai, Yanjun; Tong, Yen Wah

    2018-02-01

    The effects of activated carbon (AC) on methane production and the fate of antibiotic resistance genes (ARGs) were evaluated through comparing the anaerobic digestion performance and transformation of ARGs among anaerobic mono-digestion of food waste, co-digestion of food waste and chicken manure, and co-digestion of food waste and waste activated sludge. Results showed that adding AC in anaerobic digesters improved methane yield by at least double through the enrichment of bacteria and archaea. Conventional digestion process showed ability in removing certain types of ARGs, such as tetA, tetX, sul1, sul2, cmlA, floR, and intl1. Supplementing AC in anaerobic digester enhanced the removal of most of the ARGs in mono-digestion of food waste. The effects tended to be minimal in co-digestion of co-substrates such as chicken manure and waste activated sludge, both of which contain a certain amount of antibiotics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Oxidation of fluoroquinolone antibiotics and structurally related amines by chlorine dioxide: Reaction kinetics, product and pathway evaluation.

    Science.gov (United States)

    Wang, Pei; He, Yi-Liang; Huang, Ching-Hua

    2010-12-01

    Fluoroquinolones (FQs) are a group of widely prescribed antibiotics and have been frequently detected in the aquatic environment. The reaction kinetics and transformation of seven FQs (ciprofloxacin (CIP), enrofloxacin (ENR), norfloxacin (NOR), ofloxacin (OFL), lomefloxacin (LOM), pipemidic acid (PIP) and flumequine (FLU)) and three structurally related amines (1-phenylpiperazine (PP), N-phenylmorpholine (PM) and 4-phenylpiperidine (PD)) toward chlorine dioxide (ClO(2)) were investigated to elucidate the behavior of FQs during ClO(2) disinfection processes. The reaction kinetics are highly pH-dependent, can be well described by a second-order kinetic model incorporating speciation of FQs, and follow the trend of OFL > ENR > CIP ∼ NOR ∼ LOM > > PIP in reactivity. Comparison among FQs and related amines and product characterization indicate that FQs' piperazine ring is the primary reactive center toward ClO(2). ClO(2) likely attacks FQ's piperazinyl N4 atom followed by concerted fragmentation involving piperazinyl N1 atom, leading to dealkylation, hydroxylation and intramolecular ring closure at the piperazine moiety. While FQs with tertiary N4 react faster with ClO(2) than FQs with secondary N4, the overall reactivity of the piperazine moiety also depends strongly on the quinolone ring through electronic effects. The reaction rate constants obtained in clean water matrix can be used to model the decay of CIP by ClO(2) in surface water samples, but overestimate the decay in wastewater samples. Overall, transformation of FQs, particularly for those with tertiary N4 amines, could be expected under typical ClO(2) disinfection conditions. However, the transformation may not eliminate antibacterial activity because of little destruction at the quinolone ring. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Measurement of trace levels of antibiotics in river water using on-line enrichment and triple-quadrupole LC-MS/MS.

    Science.gov (United States)

    Dinh, Quoc Tuc; Alliot, Fabrice; Moreau-Guigon, Elodie; Eurin, Joëlle; Chevreuil, Marc; Labadie, Pierre

    2011-09-15

    This study presents the development of an automated on-line solid phase extraction (SPE)-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of 23 antibiotics in environmental water samples. After optimisation of LC-MS/MS conditions, SPE parameters such as sorbent type, sample pH or sample volume were optimised. Antibiotic recoveries ranged from 64% to 98% and compared favourably with those achieved using off-line SPE. Limits of detection were in the range 0.5-13.7 ng L(-1). This on-line SPE-LC-MS/MS procedure was applied to the analysis of water samples taken in three rivers within the Seine River basin, near Paris (France). The obtained results revealed the occurrence of 12 antibiotics, including tylosin, erythromycin, tetracycline, amoxicillin, trimethoprim, sulfamethoxazole, oxolinic acid, flumequine, norfloxacin, ciprofloxacin, ofloxacin, and vancomycin (2-1435 ng L(-1)). Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Potential of berberine to enhance antimicrobial activity of commonly used antibiotics for dairy cow mastitis caused by multiple drug-resistant Staphylococcus epidermidis infection.

    Science.gov (United States)

    Zhou, X; Yang, C; Li, Y; Liu, X; Wang, Y

    2015-08-19

    Berberine is a plant alkaloid with antimicrobial activity against a variety of microorganisms. In this study, the antimicrobial properties of berberine against multi-drug resistant field isolates of Staphylococcus epidermidis were investigated using berberine alone or in combination with a commonly used antibiotics in veterinary clinics, including penicillin, lincomycin, and amoxicillin. The results indicated that the minimum inhibitory concentrations of berberine, penicillin, lincomycin, and amoxicillin against field S. epidermidis isolates were 2-512, 0.8-213, 0.4-1024, and 0.4-256 mg/mL, respectively. Furthermore, the synergistic effects of antimicrobial activity against these multi-drug resistant isolates were observed when the berberine was combined with penicillin, lincomycin, or amoxicillin; no antagonistic effect of the combination was detected in any of the clinical isolates. These observations were further confirmed using a time-killing assay, in which a combination of 2 agents yielded a greater than 2.03-2.44 log10 decrease in colony-forming unit/mL compared with each agent alone. These findings suggest that berberine is a promising compound for preventing and treating multi-drug resistant S. epidermidis infected mastitis in dairy cows either alone or in combination with other commonly used antibiotics, such as penicillin, lincomycin, and amoxicillin.

  13. BiVO4 /N-rGO nano composites as highly efficient visible active photocatalyst for the degradation of dyes and antibiotics in eco system.

    Science.gov (United States)

    Appavu, Brindha; Thiripuranthagan, Sivakumar; Ranganathan, Sudhakar; Erusappan, Elangovan; Kannan, Kathiravan

    2018-04-30

    Herein, we report the synthesis of novel nitrogen doped reduced graphene oxide/ BiVO 4 photo catalyst by single step hydrothermal method. The physicochemical properties of the catalysts were characterized using XRD, N 2 adsorption-desorption, Raman, XPS, SEM TEM, DRS-UV and EIS techniques. The synthesized catalysts were tested for their catalytic activity in the photo degradation of some harmful textile dyes (methylene blue & congo red) and antibiotics (metronidazole and chloramphenicol) under visible light irradiation. Reduced charge recombination and enhanced photocatalytic activity were observed due to the concerted effect between BiVO 4 and nitrogen-rGO. The degradation efficiency of BiVO 4 /N-rGO in the degradation of CR and MB was remarkably high i.e 95% and 98% under visible light irradiation. Similarly 95% of MTZ and 93% of CAP were degraded under visible light irradiation. HPLC studies implied that both the dyes and antibiotics were degraded to the maximum extent. The plausible photocatalytic mechanism on the basis of experimental results was suggested. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. [New antibiotics produced by Bacillus subtilis strains].

    Science.gov (United States)

    Malanicheva, I A; Kozlov, D G; Efimenko, T A; Zenkova, V A; Kastrukha, G S; Reznikova, M I; Korolev, A M; Borshchevskaia, L N; Tarasova, O D; Sineokiĭ, S P; Efremenkova, O V

    2014-01-01

    Two Bacillus subtilis strains isolated from the fruiting body of a basidiomycete fungus Pholiota squarrosa exhibited a broad range of antibacterial activity, including those against methicillin-resistant Staphylococcus aureus INA 00761 (MRSA) and Leuconostoc mes6nteroides VKPM B-4177 resistant to glycopep-> tide antibiotics, as well as antifungal activity. The strains were identified as belonging to the "B. subtilis" com- plex based on their morphological and physiological characteristics, as well as by sequencing of the 16S rRNA gene fragments. Both strains (INA 01085 and INA 01086) produced insignificant amounts of polyene antibiotics (hexaen and pentaen, respectively). Strain INA 01086 produced also a cyclic polypeptide antibiotic containing Asp, Gly, Leu, Pro, Tyr, Thr, Trp, and Phe, while the antibiotic of strain INA 01085 contained, apart from these, two unidentified nonproteinaceous amino acids. Both polypeptide antibiotics were new compounds efficient against gram-positive bacteria and able to override the natural bacterial antibiotic resistance.

  15. Elimination of Isoxazolyl-Penicillins antibiotics in waters by the ligninolytic native Colombian strain Leptosphaerulina sp. considerations on biodegradation process and antimicrobial activity removal.

    Science.gov (United States)

    Copete-Pertuz, Ledys S; Plácido, Jersson; Serna-Galvis, Efraím A; Torres-Palma, Ricardo A; Mora, Amanda

    2018-07-15

    In this work, Leptosphaerulina sp. (a Colombian native fungus) significantly removed three Isoxazolyl-Penicillin antibiotics (IP): oxacillin (OXA, 16000 μg L -1 ), cloxacillin (CLX, 17500 μg L -1 ) and dicloxacillin (DCX, 19000 μg L -1 ) from water. The biological treatment was performed at pH 5.6, 28 °C, and 160 rpm for 15 days. The biotransformation process and lack of toxicity of the final solutions (antibacterial activity (AA) and cytotoxicity) were tested. The role of enzymes in IP removal was analysed through in vitro studies with enzymatic extracts (crude and pre-purified) from Leptosphaerulina sp., commercial enzymes and enzymatic inhibitors. Furthermore, the applicability of mycoremediation process to a complex matrix (simulated hospital wastewater) was evaluated. IP were considerably abated by the fungus, OXA was the fastest degraded (day 6), followed by CLX (day 7) and DCX (day 8). Antibiotics biodegradation was associated to laccase and versatile peroxidase action. Assays using commercial enzymes (i.e. laccase from Trametes versicolor and horseradish peroxidase) and inhibitors (EDTA, NaCl, sodium acetate, manganese (II) ions) confirmed the significant role of enzymatic transformation. Whereas, biomass sorption was not an important process in the antibiotics elimination. Evaluation of AA against Staphylococcus aureus ATCC 6538 revealed that Leptosphaerulina sp. also eliminated the AA. In addition, the cytotoxicity assay (MTT) on the HepG2 cell line demonstrated that the IP final solutions were non-toxic. Finally, Leptosphaerulina sp. eliminated OXA and its AA from synthetic hospital wastewater at 6 days. All these results evidenced the potential of Leptosphaerulina sp. mycoremediation as a novel environmentally friendly process for the removal of IP from aqueous systems. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Occurrence of antibiotics in soils and manures from greenhouse vegetable production bases of Beijing, China and an associated risk assessment.

    Science.gov (United States)

    Li, Cheng; Chen, Jiayi; Wang, Jihua; Ma, Zhihong; Han, Ping; Luan, Yunxia; Lu, Anxiang

    2015-07-15

    The occurrence of 15 antibiotics in soil and manure samples from 11 large-scale greenhouse vegetable production (GVP) bases in Beijing, China was investigated. Results showed that the greenhouse soils were ubiquitously contaminated with antibiotics, and that antibiotic concentrations were significantly higher in greenhouses than in open field soils. The mean concentrations of four antibiotic classes decreased in the following order: tetracyclines (102μg/kg)>quinolones (86μg/kg)>sulfonamides (1.1μg/kg)>macrolides (0.62μg/kg). This investigation also indicated that fertilization with manure and especially animal feces might be the primary source of antibiotics. A risk assessment based on the calculated risk quotients (RQs) demonstrated that oxytetracycline, chlortetracycline, norfloxacin, ciprofloxacin and enrofloxacin could pose a high risk to soil organisms. These results suggested that the ecological effects of antibiotic contamination in GVP bases and their potential adverse risks on human health need to be given special attention. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. [Changes of resistant phenotype and CRISPR/Cas system of four Shigella strains passaged for 90 times without antibiotics].

    Science.gov (United States)

    Zhang, B; Hong, L J; Duan, G C; Liang, W J; Yang, H Y; Xi, Y L

    2017-02-10

    Objective: To explore the stability of resistant phenotypes and changes of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) gene system on four Shigella strains in the absence of antibiotics. Methods: Four clinical isolated Shigella strains that resistant to different antibiotics were consecutive passaged for 90 times without antibiotics. Agar dilution method was used to determine the minimum inhibitory concentration of Shigella strains. After sequence analysis with PCR, CRISPR Finder and Clustal X 2.1 were applied to identify the changes of CRISPR loci in the Shigella strains. Results: After the consecutive transfer of 90 generations, sensitivity to certain antibiotics of four Shigella strains with different drug resistant spectrums increased. Mel-sf1998024/zz resistance to ampicillin, cephalexin, cefotaxime, chloramphenicol decreased, mel-s2014026/sx resistance to norfloxacin, trimethoprim decreased, mel-sf2004004/sx drug resistance to ampicillin, cefuroxime, cefotaxime, chloramphenicol, trimethoprim decreased and mel-sf2013004/bj resistance to chloramphenicol decreased. The spacer of which matched gene codes Cas and its upstream repeat in 3'end of CRISPR3 got lost in mel-sf1998024/zz and mel-sf2013004/bj. Conclusions: Shigella strains could reduce or lose their resistance to some antibiotics after consecutive transfers, without the interference of antibiotics. CRISPR3 locus had dynamic spacers in Shigella strains while CRISPR3 locus and cas genes might have been co-evolved.

  18. UPLC-MS/MS analysis of antibiotics in pharmaceutical effluent in Tunisia: ecotoxicological impact and multi-resistant bacteria dissemination.

    Science.gov (United States)

    Tahrani, Leyla; Mehri, Ines; Reyns, Tim; Anthonissen, Roel; Verschaeve, Luc; Khalifa, Anis Bel Haj; Loco, Joris Van; Abdenaceur, Hassen; Mansour, Hedi Ben

    2018-05-01

    The UPLC MS/MS analysis showed the presence of the two antibiotics in the pharmaceutical industry discharges during 3 months; norfloxacin and spiramycin which were quantified with the mean concentrations of 226.7 and 84.2 ng mL -1 , respectively. Sixteen resistant isolates were obtained from the pharmaceutical effluent and identified by sequencing. These isolates belong to different genera, namely Citrobacter, Acinetobacter, Pseudomonas, Delftia, Shewanella, and Rheinheimera. The antibiotic resistance phenotypes of these isolates were determined (27 tested antibiotics-discs). All the studied isolates were found resistant to amoxicillin and gentamicin, and 83.33% of isolates were resistant to ciprofloxacin. Multiple antibiotic resistances were revealed against β-lactams, quinolones, and aminoglycosides families. Our overall results suggest that the obtained bacterial isolates may constitute potential candidates for bioremediation and can be useful for biotechnological applications. Genotoxic effects were assessed by a battery of biotests; the pharmaceutical wastewater was genotoxic according to the bacterial Vitotox test and micronuclei test. Genotoxicity was also evaluated by the comet test; the tail DNA damages reached 38 and 22% for concentrated sample (10×) and non-concentrated sample (1×), respectively. However, the histological sections of kidney and liver's mice treated by pharmaceutical effluent showed normal histology and no visible structural effects or alterations as cytolysis, edema, or ulcerative necrosis were observed. Residual antibiotics can reach water environment through wastewater and provoke dissemination of the antibiotics resistance and induce genotoxic effects.

  19. Identification of antibiotic resistant bacteria community and a GeoChip based study of resistome in urban watersheds.

    Science.gov (United States)

    Low, Adrian; Ng, Charmaine; He, Jianzhong

    2016-12-01

    Urban watersheds from point sources are potential reservoirs of antibiotic resistance genes (ARGs). However, few studies have investigated urban watersheds of non-point sources. To understand the type of ARGs and bacteria that might carry such genes, we investigated two non-point source urban watersheds with different land-use profiles. Antibiotic resistance levels of two watersheds (R1, R3) were examined using heterotrophic plate counts (HPC) as a culturing method to obtain counts of bacteria resistant to seven antibiotics belonging to different classes (erythromycin, kanamycin, lincomycin, norfloxacin, sulfanilamide, tetracycline and trimethoprim). From the HPC study, 239 antibiotic resistant bacteria were characterized for resistance to more antibiotics. Furthermore, ARGs and antimicrobial biosynthesis genes were identified using GeoChip version 5.0 to elucidate the resistomes of surface waters in watersheds R1 and R3. The HPC study showed that water samples from R1 had significantly higher counts of bacteria resistant to erythromycin, kanamycin, norfloxacin, sulfanilamide, tetracycline and trimethoprim than those from R3 (Analysis of Similarity (ANOSIM), R = 0.557, p antibiotics tested, lincomycin and trimethoprim resistant bacteria are greater in abundances. The 239 antibiotic resistant isolates represent a subset of resistant bacterial populations, including bacteria not previously known for resistance. Majority of the isolates had resistance to ampicillin, vancomycin, lincomycin and trimethoprim. GeoChip revealed similar ARGs in both watersheds, but with significantly higher intensities for tetX and β-lactamase B genes in R1 than R3. The genes with the highest average normalized intensities in R1 and R3 were tetracycline (tet) and fosfomycin (fosA) resistance genes, respectively. The higher abundance of tetX genes in R1 is congruent with the higher abundance of tetracycline resistant HPC observed in R1 samples. Strong correlations (r ≥ 0.8) of efflux

  20. Antibacterial and antibiotic-potentiation activities of the methanol extract of some cameroonian spices against Gram-negative multi-drug resistant phenotypes

    Science.gov (United States)

    2012-01-01

    Background The present work was designed to evaluate the antibacterial properties of the methanol extracts of eleven selected Cameroonian spices on multi-drug resistant bacteria (MDR), and their ability to potentiate the effect of some common antibiotics used in therapy. Results The extract of Cinnamomum zeylanicum against Escherichia coli ATCC 8739 and AG100 strains showed the best activities, with the lowest minimal inhibitory concentration (MIC) of 64 μg/ml. The extract of Dorstenia psilurus was the most active when tested in the presence of an efflux pump inhibitor, phenylalanine Arginine-β- Naphtylamide (PAβN), a synergistic effect being observed in 56.25 % of the tested bacteria when it was combined with Erythromycin (ERY). Conclusion The present work evidently provides information on the role of some Cameroonian spices in the fight against multi-resistant bacteria. PMID:22709668

  1. Antibacterial and antibiotic-potentiation activities of the methanol extract of some cameroonian spices against Gram-negative multi-drug resistant phenotypes

    Directory of Open Access Journals (Sweden)

    Voukeng Igor K

    2012-06-01

    Full Text Available Abstract Background The present work was designed to evaluate the antibacterial properties of the methanol extracts of eleven selected Cameroonian spices on multi-drug resistant bacteria (MDR, and their ability to potentiate the effect of some common antibiotics used in therapy. Results The extract of Cinnamomum zeylanicum against Escherichia coli ATCC 8739 and AG100 strains showed the best activities, with the lowest minimal inhibitory concentration (MIC of 64 μg/ml. The extract of Dorstenia psilurus was the most active when tested in the presence of an efflux pump inhibitor, phenylalanine Arginine-β- Naphtylamide (PAβN, a synergistic effect being observed in 56.25 % of the tested bacteria when it was combined with Erythromycin (ERY. Conclusion The present work evidently provides information on the role of some Cameroonian spices in the fight against multi-resistant bacteria.

  2. Removal of Antibiotics in Biological Wastewater Treatment Systems-A Critical Assessment Using the Activated Sludge Modeling Framework for Xenobiotics (ASM-X).

    Science.gov (United States)

    Polesel, Fabio; Andersen, Henrik R; Trapp, Stefan; Plósz, Benedek Gy

    2016-10-04

    Many scientific studies present removal efficiencies for pharmaceuticals in laboratory-, pilot-, and full-scale wastewater treatment plants, based on observations that may be impacted by theoretical and methodological approaches used. In this Critical Review, we evaluated factors influencing observed removal efficiencies of three antibiotics (sulfamethoxazole, ciprofloxacin, tetracycline) in pilot- and full-scale biological treatment systems. Factors assessed include (i) retransformation to parent pharmaceuticals from e.g., conjugated metabolites and analogues, (ii) solid retention time (SRT), (iii) fractions sorbed onto solids, and (iv) dynamics in influent and effluent loading. A recently developed methodology was used, relying on the comparison of removal efficiency predictions (obtained with the Activated Sludge Model for Xenobiotics (ASM-X)) with representative measured data from literature. By applying this methodology, we demonstrated that (a) the elimination of sulfamethoxazole may be significantly underestimated when not considering retransformation from conjugated metabolites, depending on the type (urban or hospital) and size of upstream catchments; (b) operation at extended SRT may enhance antibiotic removal, as shown for sulfamethoxazole; (c) not accounting for fractions sorbed in influent and effluent solids may cause slight underestimation of ciprofloxacin removal efficiency. Using tetracycline as example substance, we ultimately evaluated implications of effluent dynamics and retransformation on environmental exposure and risk prediction.

  3. Plasmid Mediated Antibiotic and Heavy Metal Resistance in Bacillus Strains Isolated From Soils in Rize, Turkey

    Directory of Open Access Journals (Sweden)

    Elif SEVİM

    2015-09-01

    Full Text Available Fifteen Bacillus strains which were isolated from soil samples were examined for resistance to 17 different antibiotics (ampicillin, methicillin, erythromycin, norfloxacin, cephalotine, gentamycin, ciprofloxacin, streptomycin, tobramycin, chloramphenicol, trimethoprim-sulfamethoxazole, tetracycline, vancomycin, oxacilin, neomycin, kanamycin and, novabiocin and to 10 different heavy metals (copper, lead, cobalt, chrome, iron, mercury, zinc, nickel, manganese and, cadmium and for the presence of plasmid DNA. A total of eleven strains (67% were resistant to at least one antibiotic. The most common resistance was observed against methicillin and oxacillin. The most resistance strains were found as Bacillus sp. B3 and Bacillus sp. B11. High heavy metal resistance against copper, chromium, zinc, iron and nickel was detected, but mercury and cobalt resistance was not detected, except for 3 strains (B3, B11, and B12 which showed mercury resistance. It has been determined that seven Bacillus strains have plasmids. The isolated plasmids were transformed into the Bacillus subtilis W168 and it was shown that heavy metal and antibiotic resistance determinants were carried on these plasmids. These results showed that there was a correlation between plasmid content and resistance for both antibiotic and heavy metal resistance

  4. Ileumycin, a new antibiotic against Glomerella Cingulata.

    Science.gov (United States)

    Kawakami, Y; Matsuwaka, S; Otani, T; Kondo, H; Nakamura, S

    1978-02-01

    A new antifungal antibiotic, named ileumycin, was isolated from culture broth of streptomyces H 698-SY2, which was identified as S. lavendulae. The antibiotic was recovered from the culture filtrate by adsorption on Amberlite XAD-II and elution with aqueous methanol and was further purified by ion-exchange column chromatography on SE-cellulose and followed by partition chromatography on silica gel. The antibiotic was named ileumycin, because isoleucine was detected in the acid hydrolyzate of the antibiotic. Ileumycin exhibited antimicrobial activity against only a few species of fungi.

  5. Antibiotic research and development: business as usual?

    Science.gov (United States)

    Harbarth, S; Theuretzbacher, U; Hackett, J

    2015-01-01

    The global burden of antibiotic resistance is tremendous and, without new anti-infective strategies, will continue to increase in the coming decades. Despite the growing need for new antibiotics, few pharmaceutical companies today retain active antibacterial drug discovery programmes. One reason is that it is scientifically challenging to discover new antibiotics that are active against the antibiotic-resistant bacteria of current clinical concern. However, the main hurdle is diminishing economic incentives. Increased global calls to minimize the overuse of antibiotics, the cost of meeting regulatory requirements and the low prices of currently marketed antibiotics are strong deterrents to antibacterial drug development programmes. New economic models that create incentives for the discovery of new antibiotics and yet reconcile these incentives with responsible antibiotic use are long overdue. DRIVE-AB is a €9.4 million public-private consortium, funded by the EU Innovative Medicines Initiative, that aims to define a standard for the responsible use of antibiotics and to develop, test and recommend new economic models to incentivize investment in producing new anti-infective agents. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. Redox biotransformation and delivery of anthracycline anticancer antibiotics: How interpretable structure-activity relationships of lethality using electrophilicity and the London formula for dispersion interaction work.

    Science.gov (United States)

    Pang, Siu-Kwong

    2017-03-30

    Quantum chemical methods and molecular mechanics approaches face a lot of challenges in drug metabolism study because of their either insufficient accuracy or huge computational cost, or lack of clear molecular level pictures for building computational models. Low-cost QSAR methods can often be carried out even though molecular level pictures are not well defined; however, they show difficulty in identifying the mechanisms of drug metabolism and delineating the effects of chemical structures on drug toxicity because a certain amount of molecular descriptors are difficult to be interpreted. In order to make a breakthrough, it was proposed that mechanistically interpretable molecular descriptors were used to correlate with biological activity to establish structure-activity plots. The mechanistically interpretable molecular descriptors used in this study include electrophilicity and the mathematical function in the London formula for dispersion interaction, and they were calculated using quantum chemical methods. The biological activity is the lethality of anthracycline anticancer antibiotics denoted as log LD50, which were obtained by intraperitoneal injection into mice. The results reveal that the plots for electrophilicity, which can be interpreted as redox reactivity of anthracyclines, can describe oxidative degradation for detoxification and reductive bioactivation for toxicity induction. The plots for the dispersion interaction function, which represent the attraction between anthracyclines and biomolecules, can describe efflux from and influx into target cells of toxicity. The plots can also identify three structural scaffolds of anthracyclines that have different metabolic pathways, resulting in their different toxicity behavior. This structure-dependent toxicity behavior revealed in the plots can provide perspectives on design of anthracycline anticancer antibiotics. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. Antibiotic susceptibility profiles of Mycoplasma sp. 1220 strains isolated from geese in Hungary.

    Science.gov (United States)

    Grózner, Dénes; Kreizinger, Zsuzsa; Sulyok, Kinga M; Rónai, Zsuzsanna; Hrivnák, Veronika; Turcsányi, Ibolya; Jánosi, Szilárd; Gyuranecz, Miklós

    2016-08-19

    Mycoplasma sp. 1220 can induce inflammation primarily in the genital and respiratory tracts of waterfowl, leading to serious economic losses. Adequate housing and appropriate antibiotic treatment are promoted in the control of the disease. The aim of the present study was to determine the in vitro susceptibility to thirteen different antibiotics and an antibiotic combination of thirty-eight M. sp. 1220 strains isolated from geese and a duck in several parts of Hungary, Central Europe between 2011 and 2015. High MIC50 values were observed in the cases of tilmicosin (>64 μg/ml), oxytetracycline (64 μg/ml), norfloxacin (>10 μg/ml) and difloxacin (10 μg/ml). The examined strains yielded the same MIC50 values with spectinomycin, tylosin and florfenicol (8 μg/ml), while enrofloxacin (MIC50 5 μg/ml), doxycycline (MIC50 5 μg/ml), lincomycin (MIC50 4 μg/ml) and lincomycin-spectinomycin (1:2) combination (MIC50 4 μg/ml) inhibited the growth of the bacteria with lower concentrations. Tylvalosin (MIC50 0.5 μg/ml) and two pleuromutilins (tiamulin MIC50 0.625 μg/ml; valnemulin MIC50 ≤ 0.039 μg/ml) were found to be the most effective drugs against M. sp. 1220. However, strains with elevated MIC values were detected for all applied antibiotics. Valnemulin, tiamulin and tylvalosin were found to be the most effective antibiotics in the study. Increasing resistance was observed in the cases of several antibiotics. The results highlight the importance of testing Mycoplasma species for antibiotic susceptibility before therapy.

  8. Antibiotic research and development: business as usual?

    NARCIS (Netherlands)

    Harbarth, S.; Theuretzbacher, U.; Hackett, J.; Hulscher, M.; et al.,

    2015-01-01

    The global burden of antibiotic resistance is tremendous and, without new anti-infective strategies, will continue to increase in the coming decades. Despite the growing need for new antibiotics, few pharmaceutical companies today retain active antibacterial drug discovery programmes. One reason is

  9. Removal of Antibiotics in Biological Wastewater Treatment Systems—A Critical Assessment Using the Activated Sludge Modeling Framework for Xenobiotics (ASM-X)

    DEFF Research Database (Denmark)

    Polesel, Fabio; Andersen, Henrik Rasmus; Trapp, Stefan

    2016-01-01

    Many scientific studies present removal efficiencies for pharmaceuticals in laboratory-, pilot-, and full-scale wastewater treatment plants, based on observations that may be impacted by theoretical and methodological approaches used. In this Critical Review, we evaluated factors influencing...... observed removal efficiencies of three antibiotics (sulfamethoxazole, ciprofloxacin, tetracycline) in pilot- and full-scale biological treatment systems. Factors assessed include (i) retransformation to parent pharmaceuticals from e.g., conjugated metabolites and analogues, (ii) solid retention time (SRT......), (iii) fractions sorbed onto solids, and (iv) dynamics in influent and effluent loading. A recently developed methodology was used, relying on the comparison of removal efficiency predictions (obtained with the Activated Sludge Model for Xenobiotics (ASM-X)) with representative measured data from...

  10. The antibiotic resistome.

    Science.gov (United States)

    Wright, Gerard D

    2010-08-01

    Antibiotics are essential for the treatment of bacterial infections and are among our most important drugs. Resistance has emerged to all classes of antibiotics in clinical use. Antibiotic resistance has, proven inevitable and very often it emerges rapidly after the introduction of a drug into the clinic. There is, therefore, a great interest in understanding the origins, scope and evolution of antibiotic resistance. The review discusses the concept of the antibiotic resistome, which is the collection of all genes that directly or indirectly contribute to antibiotic resistance. The review seeks to assemble current knowledge of the resistome concept as a means of understanding the totality of resistance and not just resistance in pathogenic bacteria. The concept of the antibiotic resistome provides a framework for the study and understanding of how resistance emerges and evolves. Furthermore, the study of the resistome reveals strategies that can be applied in new antibiotic discoveries.

  11. Phytochemical Prospection and Modulation of Antibiotic Activity In Vitro by Lippia origanoides H.B.K. in Methicillin Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Humberto Medeiros Barreto

    2014-01-01

    Full Text Available The Lippia origanoides H.B.K. ethanol extract (LOEE and hexane (LOHEX, dichloromethane (LODCM, and ethyl acetate (LOEA fractions were tested for their antimicrobial activity alone or in combination with antibiotics against a methicillin resistant Staphylococcus aureus (MRSA strain. The natural products did not show antimicrobial activity against multidrug resistant strain at the clinically significant concentrations tested. However, a modulatory effect in the antibacterial activity of the neomycin and amikacin was verified when LOEE, LOHEX and LODCM were added to the growth medium at subinhibitory concentrations. A similar modulation was found when the natural products were changed for chlorpromazine, an inhibitor of bacterial efflux pumps, suggesting the involvement of resistance mediated by efflux system in the MRSA tested. The fractions LOHEX and LODCM showed a modulatory activity bigger than their majority compounds (carvacrol, thymol, and naringenin, indicating that this activity is not due to their majority compounds only, but it is probably due to a synergism between their chemical components. These results indicate that L. origanoides H.B.K. can be a source of phytochemicals able to modify the phenotype of resistance to aminoglycosides in MRSA.

  12. Know When Antibiotics Work

    Centers for Disease Control (CDC) Podcasts

    2015-04-15

    This podcast provides a brief background about antibiotics and quick tips to help prevent antibiotic resistance.  Created: 4/15/2015 by Division of Bacterial Diseases (DBD), National Center for Immunization and Respiratory Disease (NCIRD), Get Smart: Know When Antibiotics Work Program.   Date Released: 4/16/2015.

  13. Antibiotics: Miracle Drugs

    Centers for Disease Control (CDC) Podcasts

    The overuse of antibiotics has led to the development of resistance among bacteria, making antibiotics ineffective in treating certain conditions. This podcast discusses the importance of talking to your healthcare professional about whether or not antibiotics will be beneficial if you've been diagnosed with an infectious disease.

  14. Bactericidal antibiotics induce programmed metabolic toxicity

    Directory of Open Access Journals (Sweden)

    Aislinn D. Rowan

    2016-03-01

    Full Text Available The misuse of antibiotics has led to the development and spread of antibiotic resistance in clinically important pathogens. These resistant infections are having a significant impact on treatment outcomes and contribute to approximately 25,000 deaths in the U.S. annually. If additional therapeutic options are not identified, the number of annual deaths is predicted to rise to 317,000 in North America and 10,000,000 worldwide by 2050. Identifying therapeutic methodologies that utilize our antibiotic arsenal more effectively is one potential way to extend the useful lifespan of our current antibiotics. Recent studies have indicated that modulating metabolic activity is one possible strategy that can impact the efficacy of antibiotic therapy. In this review, we will address recent advances in our knowledge about the impacts of bacterial metabolism on antibiotic effectiveness and the impacts of antibiotics on bacterial metabolism. We will particularly focus on two studies, Lobritz, et al. (PNAS, 112(27: 8173-8180 and Belenky et al. (Cell Reports, 13(5: 968–980 that together demonstrate that bactericidal antibiotics induce metabolic perturbations that are linked to and required for bactericidal antibiotic toxicity.

  15. ASP Strategies and Appropriate Antibiotic Use

    Science.gov (United States)

    Lee, Brian R; Tribble, Alison; Handy, Lori; Gerber, Jeffrey S; Hersh, Adam L; Kronman, Matthew; Terrill, Cindy; Newland, Jason

    2017-01-01

    Abstract Background The Infectious Diseases Society of America (IDSA) recommends hospitals implement antimicrobial stewardship programs (ASP) in order to decrease inappropriate antibiotic use due to the rise in antibiotic-resistant infections. Data are limited on the extent to which different ASP strategies influence appropriate antibiotic use. Methods We conducted an online survey in 2016 of U.S. Children’s Hospitals to collect hospital-level information on dedicated ASP effort, ASP monitoring activities, use of audit-feedback, formulary restrictions, rapid diagnostics, etc. During the same period the ASP teams at these hospitals completed 3 point prevalence surveys that documented details on all admitted patients 0–17 years receiving any antibiotics, determined what ASP modifications could be made, and if the antibiotic was appropriate. We employed hierarchical, multivariable logit models to examine which ASP-related, hospital-level strategies were associated with appropriate antibiotic use. Results Thirty hospitals participated. A total of 6,921 patients were included, representing 10,068 total antibiotics. Of these orders, 8,554 (85.0%) were categorized as appropriate, though this varied across sites (range: 68-92%). Additionally, 78.2% of antibiotics did not have recommended modifications. Appropriate antibiotic use was significantly higher for hospitals that relied on rapid diagnostics (aOR: 1.6; P Terrill, Merck: Grant Investigator, Research grant Allergan: Grant Investigator, Research grant. J. Newland, Merck: Grant Investigator, Research grant. Allergan: Grant Investigator, Research grant

  16. Recent updates of carbapenem antibiotics.

    Science.gov (United States)

    El-Gamal, Mohammed I; Brahim, Imen; Hisham, Noorhan; Aladdin, Rand; Mohammed, Haneen; Bahaaeldin, Amany

    2017-05-05

    Carbapenems are among the most commonly used and the most efficient antibiotics since they are relatively resistant to hydrolysis by most β-lactamases, they target penicillin-binding proteins, and generally have broad-spectrum antibacterial effect. In this review, we described the initial discovery and development of carbapenems, chemical characteristics, in vitro/in vivo activities, resistance studies, and clinical investigations for traditional carbapenem antibiotics in the market; imipenem-cilastatin, meropenem, ertapenem, doripenem, biapenem, panipenem/betamipron in addition to newer carbapenems such as razupenem, tebipenem, tomopenem, and sanfetrinem. We focused on the literature published from 2010 to 2016. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Antibiotic and fermentative activity of bacteria found in water and digestive tract of fish from Lake Drukshiai at Ignalina Nuclear Power Plant

    International Nuclear Information System (INIS)

    Lubianskiene, V.; Jastiuginiene, R.

    1996-01-01

    The composition and antagonistic activity of microflora found in water and digestive tract of roaches - fish, which prevail in Lake Drukshiai, were investigated. The investigations revealed that unfavourable environmental conditions first of all gave rise to the changes in bacteria composition. It has been found that the bacteria of g. Vibrio, prevailed, their virulentic properties became more intense, antibiotical properties weakened, the prevailing microflora lost its ability to fight with pathogenic microorganisms. An increased lysozymic activity of g. Vibrio bacteria in the intestinal tract of fishes shows their resistance to phagocytosis and ability to stay for a long time in the digestive tract. The high antilysozymic activity of g. Vibrio bacteria in fishes digestive tract shows their ability to inactivate the lysozyme secreted by cells of organism reaction to pathogenic microflora. Antilysozymic and lysozymic activity of g. Vibrio bacteria is supposed to be one of the causes predetermining the predominance of this genus in biocenosis. The predominance of g. Vibrio bacteria in biocenosis of water and fish digestive tract bacteria, the strengthening of their virulentic properties speak for poor microecological conditions in the lake and lower immunological state of fish. 15 refs., 7 figs

  18. Ten years of antibiotic consumption in ambulatory care: Trends in prescribing practice and antibiotic resistance in Austria

    Directory of Open Access Journals (Sweden)

    Apfalter Petra

    2009-05-01

    Full Text Available Abstract Background The primary aims of this study were (i to determine the quantity and pattern of antibiotic use in Austria between 1998 and 2007 and (ii to analyze antibiotic resistance rates in relation to antibiotic consumption in important clinical situations in order to provide data for empirical therapeutic regimens for key indications. Methods Consumption data and resistance data were obtained via the Austrian surveillance networks European Antimicrobial Resistance Surveillance System (EARSS and European Surveillance on Antimicrobial Consumption (ESAC. The EARSS collects data on isolates from blood and cerebrospinal fluid obtained predominantly in the hospital setting. The Anatomical Therapeutic Chemical (ATC classification and the Defined Daily Dose (DDD measurement units were assigned to the data. The number of DDDs and packages per 1,000 inhabitants (PID were used to calculate the level of antibiotic consumption. Antibiotic resistance was expressed in resistance rates, i.e., the percentage of resistant isolates compared to all isolates of one bacterial species. Results The overall antibiotic consumption measured in DIDs increased by 10% between 1998 and 2007, whereas PIDs decreased by 3%. The consumption of substances within the drug utilization 90% segment (measured in PID increased for ciprofloxacin (+118.9, clindamycin (+76.3, amoxicillin/clavulanic acid (+61.9%, cefpodoxime (+31.6, azithromycin (+24.7; and decreased for erythromycin (-79.5%, trimethoprim (-56,1%, norfloxacin (-48.8%, doxycycline (-44.6, cefaclor (-35.1%, penicillin (-34.0%, amoxicillin (-22.5, minocycline (-21.9% and clarithromycin (-9.9%. Starting in 2001, an increase in the percentage of invasive E. coli isolates resistant to aminopenicillins (from 35% to 53%, fluoroquinolones (from 7% to 25.5% and third-generation cephalosporins (from 0% to 8.8% was observed. The percentage of nonsusceptible or intermediate penicillin-resistant pneumococcal isolates remained

  19. Systemic antibiotics in periodontics.

    Science.gov (United States)

    Slots, Jørgen

    2004-11-01

    This position paper addresses the role of systemic antibiotics in the treatment of periodontal disease. Topical antibiotic therapy is not discussed here. The paper was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology. The document consists of three sections: 1) concept of antibiotic periodontal therapy; 2) efficacy of antibiotic periodontal therapy; and 3) practical aspects of antibiotic periodontal therapy. The conclusions drawn in this paper represent the position of the American Academy of Periodontology and are intended for the information of the dental profession.

  20. A non-polyene antifungal antibiotic from Streptomyces albidoflavus ...

    Indian Academy of Sciences (India)

    Unknown

    One promising strain, Streptomyces albidoflavus PU 23 with strong anti- fungal activity against pathogenic fungi was selected for further studies. Antibiotic was extracted and purified from the isolate. Aspergillus spp. was most sensitive to the antibiotic followed by other molds and yeasts. The antibiotic was stable at different ...

  1. The importance of active learning and practice on the students' mastery of pharmacokinetic calculations for the intermittent intravenous infusion dosing of antibiotics

    Directory of Open Access Journals (Sweden)

    Mehvar Reza

    2012-11-01

    Full Text Available Abstract Background Estimation of pharmacokinetic parameters after intermittent intravenous infusion (III of antibiotics, such as aminoglycosides or vancomycin, has traditionally been a difficult subject for students in clinical pharmacology or pharmacokinetic courses. Additionally, samples taken at different intervals during repeated dose therapy require manipulation of sampling times before accurate calculation of the patient-specific pharmacokinetic parameters. The main goal of this study was to evaluate the effectiveness of active learning tools and practice opportunities on the ability of students to estimate pharmacokinetic parameters from the plasma samples obtained at different intervals following intermittent intravenous infusion. Methods An extensive reading note, with examples, and a problem case, based on a patient’s chart data, were created and made available to students before the class session. Students were required to work through the case before attending the class. The class session was devoted to the discussion of the case requiring active participation of the students using a random participation program. After the class, students were given additional opportunities to practice the calculations, using online modules developed by the instructor, before submitting an online assignment. Results The performance of students significantly (P P  Conclusions Despite being a difficult subject, students achieve mastery of pharmacokinetic calculations for the topic of intermittent intravenous infusion when appropriate active learning strategies and practice opportunities are employed.

  2. Environmental dissemination of antibiotic resistance genes and correlation to anthropogenic contamination with antibiotics

    Science.gov (United States)

    Berglund, Björn

    2015-01-01

    Antibiotic resistance is a growing problem which threatens modern healthcare globally. Resistance has traditionally been viewed as a clinical problem, but recently non-clinical environments have been highlighted as an important factor in the dissemination of antibiotic resistance genes (ARGs). Horizontal gene transfer (HGT) events are likely to be common in aquatic environments; integrons in particular are well suited for mediating environmental dissemination of ARGs. A growing body of evidence suggests that ARGs are ubiquitous in natural environments. Particularly, elevated levels of ARGs and integrons in aquatic environments are correlated to proximity to anthropogenic activities. The source of this increase is likely to be routine discharge of antibiotics and resistance genes, for example, via wastewater or run-off from livestock facilities and agriculture. While very high levels of antibiotic contamination are likely to select for resistant bacteria directly, the role of sub-inhibitory concentrations of antibiotics in environmental antibiotic resistance dissemination remains unclear. In vitro studies have shown that low levels of antibiotics can select for resistant mutants and also facilitate HGT, indicating the need for caution. Overall, it is becoming increasingly clear that the environment plays an important role in dissemination of antibiotic resistance; further studies are needed to elucidate key aspects of this process. Importantly, the levels of environmental antibiotic contamination at which resistant bacteria are selected for and HGT is facilitated at should be determined. This would enable better risk analyses and facilitate measures for preventing dissemination and development of antibiotic resistance in the environment. PMID:26356096

  3. Prevalent serogroups and antibiotic sensitivity of Neisseria gonorrhoeae

    Directory of Open Access Journals (Sweden)

    Aggarwal S

    1992-01-01

    Full Text Available One hundred and thirty two cases clinically labeled as acute gonorrhoea were investigated for gonococcal etiology. Smears were positive in 110 (83.3% cases and among these N. gonorrhoeae could be identified in 102 (77.3% cases by culture method. Strains were examined for serogrouping by monoclonal GC test which utilizes the principle of co-agglutination and detects the antigens of outer membrane protein. 96(94.1% strains belonged to serogroup W II/III, showing it to be the major serogroup circulating in the community. The strains were tested for sensitivity against 7 antibiotics. The largest proportion (30.4% of strains were resistant to penicillin (MIC>O. 125 IU/ml. Resistance to cotrimoxazole, erythromycin, cephalaxin and tetracycline was noted as 18.6, 17.6, 7.8 and 5.8 percent respectively. Strains showing resistance concurrently to two or more drugs were observed. All restrains were sensitive to gentamicin and norfloxacin. None of the strains was penicillinase producer.

  4. The expression of antibiotic resistance genes in antibiotic-producing bacteria.

    Science.gov (United States)

    Mak, Stefanie; Xu, Ye; Nodwell, Justin R

    2014-08-01

    Antibiotic-producing bacteria encode antibiotic resistance genes that protect them from the biologically active molecules that they produce. The expression of these genes needs to occur in a timely manner: either in advance of or concomitantly with biosynthesis. It appears that there have been at least two general solutions to this problem. In many cases, the expression of resistance genes is tightly linked to that of antibiotic biosynthetic genes. In others, the resistance genes can be induced by their cognate antibiotics or by intermediate molecules from their biosynthetic pathways. The regulatory mechanisms that couple resistance to antibiotic biosynthesis are mechanistically diverse and potentially relevant to the origins of clinical antibiotic resistance. © 2014 John Wiley & Sons Ltd.

  5. Antibiotics Susceptibility Pattern of Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    ABSTRACT: This work investigated the prevalence and antibiotics sensitivity of Pseudomonas aeruginosa isolated from ... skin triggers coagulation and an acute inflammatory response ... agents with anti-pseudomonal activity, life-threatening.

  6. Anti-Inflammatory, Antioxidant, Antibiotic, and Cytotoxic Activities of Tanacetum vulgare L. Essential Oil and Its Constituents

    Directory of Open Access Journals (Sweden)

    Héloïse Coté

    2017-05-01

    Full Text Available Background: Tanacetum vulgare L. (Asteraceae is a perennial herb that has been used to treat multiple ailments. Regional variability of the chemical composition of T. vulgare essential oils is well-known. Despite these regional chemotypes, most relevant studies did not analyze the complete chemical composition of the T. vulgare essential oil and its constituents in relation to their biological activities. Here, we assess the anti-inflammatory, antioxidant, antibacterial, and cytotoxic activities of T. vulgare collected from northern Quebec (Saguenay-Lac-St-Jean, Canada. Methods: Essential oil was extracted from plants by steam distillation and analyzed using GC-FID. Biological activities of essential oil and its main constituents were evaluated in vitro. Results: We identified the major compounds as camphor, borneol, and 1,8-cineole. The oil possesses anti-inflammatory activity inhibiting NO production. It also inhibits intracellular DCFH oxidation induced by tert-butylhydroperoxide. Anti-inflammatory activity of essential oil appears driven mainly by α-humulene while antioxidant activity is provided by α-pinene and caryophyllene oxide. Essential oil from T vulgare was active against both Escherichia coli and Staphylococcus aureus with camphor and caryophyllene oxide responsible for antibacterial activity. Finally, T. vulgare essential oil was slightly cytotoxic against the human healthy cell line WS1 while α-humulene and caryophyllene oxide were moderately cytotoxic against A-549, DLD-1, and WS1. Conclusion: We report, for the first time, links between the specific compounds found in T. vulgare essential oil and anti-inflammatory, antioxidant, antibacterial, and cytotoxic activities. T. vulgare essential oil possesses interesting biological properties.

  7. Anti-Inflammatory, Antioxidant, Antibiotic, and Cytotoxic Activities of Tanacetum vulgare L. Essential Oil and Its Constituents.

    Science.gov (United States)

    Coté, Héloïse; Boucher, Marie-Anne; Pichette, André; Legault, Jean

    2017-05-25

    Background: Tanacetum vulgare L. (Asteraceae) is a perennial herb that has been used to treat multiple ailments. Regional variability of the chemical composition of T. vulgare essential oils is well-known. Despite these regional chemotypes, most relevant studies did not analyze the complete chemical composition of the T. vulgare essential oil and its constituents in relation to their biological activities. Here, we assess the anti-inflammatory, antioxidant, antibacterial, and cytotoxic activities of T. vulgare collected from northern Quebec (Saguenay-Lac-St-Jean), Canada. Methods: Essential oil was extracted from plants by steam distillation and analyzed using GC-FID. Biological activities of essential oil and its main constituents were evaluated in vitro. Results: We identified the major compounds as camphor, borneol, and 1,8-cineole. The oil possesses anti-inflammatory activity inhibiting NO production. It also inhibits intracellular DCFH oxidation induced by tert-butylhydroperoxide. Anti-inflammatory activity of essential oil appears driven mainly by α-humulene while antioxidant activity is provided by α-pinene and caryophyllene oxide. Essential oil from T vulgare was active against both Escherichia coli and Staphylococcus aureus with camphor and caryophyllene oxide responsible for antibacterial activity. Finally, T. vulgare essential oil was slightly cytotoxic against the human healthy cell line WS1 while α-humulene and caryophyllene oxide were moderately cytotoxic against A-549, DLD-1, and WS1. Conclusion: We report, for the first time, links between the specific compounds found in T. vulgare essential oil and anti-inflammatory, antioxidant, antibacterial, and cytotoxic activities. T. vulgare essential oil possesses interesting biological properties.

  8. Ribosomal Antibiotics: Contemporary Challenges

    Directory of Open Access Journals (Sweden)

    Tamar Auerbach-Nevo

    2016-06-01

    Full Text Available Most ribosomal antibiotics obstruct distinct ribosomal functions. In selected cases, in addition to paralyzing vital ribosomal tasks, some ribosomal antibiotics are involved in cellular regulation. Owing to the global rapid increase in the appearance of multi-drug resistance in pathogenic bacterial strains, and to the extremely slow progress in developing new antibiotics worldwide, it seems that, in addition to the traditional attempts at improving current antibiotics and the intensive screening for additional natural compounds, this field should undergo substantial conceptual revision. Here, we highlight several contemporary issues, including challenging the common preference of broad-range antibiotics; the marginal attention to alterations in the microbiome population resulting from antibiotics usage, and the insufficient awareness of ecological and environmental aspects of antibiotics usage. We also highlight recent advances in the identification of species-specific structural motifs that may be exploited for the design and the creation of novel, environmental friendly, degradable, antibiotic types, with a better distinction between pathogens and useful bacterial species in the microbiome. Thus, these studies are leading towards the design of “pathogen-specific antibiotics,” in contrast to the current preference of broad range antibiotics, partially because it requires significant efforts in speeding up the discovery of the unique species motifs as well as the clinical pathogen identification.

  9. Genetic architecture of intrinsic antibiotic susceptibility.

    Directory of Open Access Journals (Sweden)

    Hany S Girgis

    2009-05-01

    Full Text Available Antibiotic exposure rapidly selects for more resistant bacterial strains, and both a drug's chemical structure and a bacterium's cellular network affect the types of mutations acquired.To better characterize the genetic determinants of antibiotic susceptibility, we exposed a transposon-mutagenized library of Escherichia coli to each of 17 antibiotics that encompass a wide range of drug classes and mechanisms of action. Propagating the library for multiple generations with drug concentrations that moderately inhibited the growth of the isogenic parental strain caused the abundance of strains with even minor fitness advantages or disadvantages to change measurably and reproducibly. Using a microarray-based genetic footprinting strategy, we then determined the quantitative contribution of each gene to E. coli's intrinsic antibiotic susceptibility. We found both loci whose removal increased general antibiotic tolerance as well as pathways whose down-regulation increased tolerance to specific drugs and drug classes. The beneficial mutations identified span multiple pathways, and we identified pairs of mutations that individually provide only minor decreases in antibiotic susceptibility but that combine to provide higher tolerance.Our results illustrate that a wide-range of mutations can modulate the activity of many cellular resistance processes and demonstrate that E. coli has a large mutational target size for increasing antibiotic tolerance. Furthermore, the work suggests that clinical levels of antibiotic resistance might develop through the sequential accumulation of chromosomal mutations of small individual effect.

  10. Antibiotics: Precious Goods in Changing Times.

    Science.gov (United States)

    Sass, Peter

    2017-01-01

    Antibiotics represent a first line of defense of diverse microorganisms, which produce and use antibiotics to counteract natural enemies or competitors for nutritional resources in their nearby environment. For antimicrobial activity, nature has invented a great variety of mechanisms of antibiotic action that involve the perturbation of essential bacterial structures or biosynthesis pathways of macromolecules such as the bacterial cell wall, DNA, RNA, or proteins, thereby threatening the specific microbial lifestyle and eventually even survival. However, along with highly inventive modes of antibiotic action, nature also developed a comparable set of resistance mechanisms that help the bacteria to circumvent antibiotic action. Microorganisms have evolved specific adaptive responses that allow appropriately reacting to the presence of antimicrobial agents, ensuring survival during antimicrobial stress. In times of rapid development and spread of antibiotic (multi-)resistance, we need to explore new, resistance-breaking strategies to counteract bacterial infections. This chapter intends to give an overview of common antibiotics and their target pathways. It will also discuss recent advances in finding new antibiotics with novel modes of action, illustrating that nature's repertoire of innovative new antimicrobial agents has not been fully exploited yet, and we still might find new drugs that help to evade established antimicrobial resistance strategies.

  11. Antibiotic resistance profiles of Escherichia coli isolated from different water sources in the Mmabatho locality, Northwest Province, South Africa

    Directory of Open Access Journals (Sweden)

    C. Njie Ateba

    2010-03-01

    Full Text Available The antibiotic resistance profiles of Escherichia coli (E. coli, isolated from different water sources in the Mmabatho locality were evaluated. Water samples were collected from the local wastewater- and water-treatment plants, the Modimola Dam and homes in the area, and then analysed for the presence of E. coli, using standard methods. Presumptive isolates obtained were confirmed by the analytical profile index test. Antibiotic susceptibility testing was performed by the disc diffusion method. Of the 230 E. coli isolates tested, marked antibiotic resistances (over 70% were observed for erythromycin, tetracycline, ampicillin, chloramphenicol and norfloxacin. Multiple antibiotic resistance patterns were also compiled. Overall, the phenotype T-Ap-E was frequent for E. coli isolated from the local wastewater and water-treatment plants, Modimola Dam and tap water. Cluster analysis performed showed a unique antibiotic resistance pattern which suggested a link between isolates from all sampling points. The findings indicated that improper wastewater treatment may have a potential impact on the dissemination and survival of E. coli, as well as other pathogenic bacteria in water for human and animal consumption. This may result in water- and food-borne disease outbreaks with a negative effect on antibiotic therapy.

  12. Designation of pathogenic resistant bacteria in the Sparusaurata sea collected in Tunisia coastlines: Correlation with high performance liquid chromatography-tandem mass spectrometry analysis of antibiotics.

    Science.gov (United States)

    Zouiten, Amina; Mehri, Ines; Beltifa, Asma; Ghorbel, Asma; Sire, Olivier; Van Loco, Joris; Abdenaceur, Hassen; Reyns, Tim; Ben Mansour, Hedi

    2017-05-01

    Vibrio is characterized by a large number of species and some of them are human pathogens causing gastro intestinal and wound infections through the ingestion or manipulation of contaminated fishes including Vibrio parahaemolyticus and Vibrio alginolyticus. In this study, we reported the phenotypic and molecular characterization of Vibrio parahaemolyticus and Vibrio alginolyticus strains isolated from wild and farm sea bream (Sparus aurata L.) along the Tunisian coast from December 2015 to April 2016. Therefore, the antibiograms indicate a difference between farmed and wild fish. Resistance against amoxicillin antibiotic appears for the bacteria isolated from wild fish, while those from aquaculture farming presented sensitivity to amoxicillin and resistance to antibiotics colistin and fusidic acid. The chloramphenicol antibiotic exhibited a high sensitivity in all isolated bacteria. In fact, traces of amoxicillin in the organs of the fish from Hergla farm were detected by UPLC-MS/MS analysis during December 2016 to April 2016. In addition, antibiotics were detected in January 2014 with high concentration of norfloxacin 2262 ng/g in fish from Hergla coast. The results obtained in this work indicated that the use and presence of antibiotics in water impacts on the occurrence of resistant bacteria and the detection of antibiotic in fish. Copyright © 2017. Published by Elsevier Ltd.

  13. De novo design and synthesis of ultra-short peptidomimetic antibiotics having dual antimicrobial and anti-inflammatory activities.

    Science.gov (United States)

    Murugan, Ravichandran N; Jacob, Binu; Ahn, Mija; Hwang, Eunha; Sohn, Hoik; Park, Hyo-Nam; Lee, Eunjung; Seo, Ji-Hyung; Cheong, Chaejoon; Nam, Ky-Youb; Hyun, Jae-Kyung; Jeong, Ki-Woong; Kim, Yangmee; Shin, Song Yub; Bang, Jeong Kyu

    2013-01-01

    Much attention has been focused on the design and synthesis of potent, cationic antimicrobial peptides (AMPs) that possess both antimicrobial and anti-inflammatory activities. However, their development into therapeutic agents has been limited mainly due to their large size (12 to 50 residues in length) and poor protease stability. In an attempt to overcome the issues described above, a set of ultra-short, His-derived antimicrobial peptides (HDAMPs) has been developed for the first time. Through systematic tuning of pendant hydrophobic alkyl tails at the N(π)- and N(τ)-positions on His, and the positive charge of Arg, much higher prokaryotic selectivity was achieved, compared to human AMP LL-37. Additionally, the most potent HDAMPs showed promising dual antimicrobial and anti-inflammatory activities, as well as anti-methicillin-resistant Staphylococcus aureus (MRSA) activity and proteolytic resistance. Our results from transmission electron microscopy, membrane depolarization, confocal laser-scanning microscopy, and calcein-dye leakage experiments propose that HDAMP-1 kills microbial cells via dissipation of the membrane potential by forming pore/ion channels on bacterial cell membranes. The combination of the ultra-short size, high-prokaryotic selectivity, potent anti-MRSA activity, anti-inflammatory activity, and proteolytic resistance of the designed HDAMP-1, -3, -5, and -6 makes these molecules promising candidates for future antimicrobial therapeutics.

  14. Antibiotics and Breastfeeding.

    Science.gov (United States)

    de Sá Del Fiol, Fernando; Barberato-Filho, Silvio; de Cássia Bergamaschi, Cristiane; Lopes, Luciane Cruz; Gauthier, Timothy P

    2016-01-01

    During the breastfeeding period, bacterial infections can occur in the nursing mother, requiring the use of antibiotics. A lack of accurate information may lead health care professionals and mothers to suspend breastfeeding, which may be unnecessary. This article provides information on the main antibiotics that are appropriate for clinical use and the interference of these antibiotics with the infant to support medical decisions regarding the discontinuation of breastfeeding. We aim to provide information on the pharmacokinetic factors that interfere with the passage of antibiotics into breast milk and the toxicological implications of absorption by the infant. Publications related to the 20 most frequently employed antibiotics and their transfer into breast milk were evaluated. The results demonstrate that most antibiotics in clinical use are considered suitable during breastfeeding; however, the pharmacokinetic profile of each drug must be observed to ensure the resolution of the maternal infection and the safety of the infant. © 2016 S. Karger AG, Basel.

  15. High Antibiotic Consumption

    DEFF Research Database (Denmark)

    Malo, Sara; José Rabanaque, María; Feja, Cristina

    2014-01-01

    Heavy antibiotic users are those individuals with the highest exposure to antibiotics. They play an important role as contributors to the increasing risk of antimicrobial resistance. We applied different methods to identify and characterize the group of heavy antibiotic users in Spain as well...... as their exposure to antibiotics. Data on outpatient prescribing of antimicrobials (ATC J01) in 2010 were obtained from a prescription database covering Aragón (northeastern Spain). The antimicrobial consumption at the individual level was analysed both according to the volume of DDD and the number of packages...... purchased per year. Heavy antibiotic users were identified according to Lorenz curves and characterized by age, gender, and their antimicrobial prescription profile. Lorenz curves demonstrated substantial differences in the individual use of antimicrobials. Heavy antibiotic users (5% of individuals...

  16. In vitro activities of beta-lactam antibiotics alone and in combination with sulbactam against Gram-negative bacteria.

    Science.gov (United States)

    Wang, Fu-Der; Lin, Mei-Lin; Lee, Wen-Sen; Liu, Cheng-Yi

    2004-06-01

    The resistance rates of ampicillin/sulbactam 2:1 against imipenem-susceptible and -resistant Acinetobacter baumannii were 23.5 and 30%, respectively. Ceftazidime/sulbactam combination showed significant reduction of resistant rates against Enterobacter cloacae, A. baumannii, ESBL Klebsiella pneumoniae. MIC90 of cefoperazone against E. cloacae, Serratia marcescens, A. baumannii and ESBL K. pneumoniae were > 128 mg/l. Addition of sulbactam enhanced the antimicrobial activities significantly. When imipenem was combined with sulbactam, the resistant rates against imipenem-resistant A. baumanni were significantly reduced. Cefepime/sulbactam combination was active against imipenem-resistant A. baumanni. The resistance rates of aztreonam/sulbactam combination against E. cloacae, imipenem-sensitive and resistant A. baumannii, ESBL K. pneumoniae were lowered significantly. The cefotaxime/sulbactam combination showed a significant improvement of activities against E. cloacae, S. marcescens, A. baumannii and ESBL K. pneumoniae. Copyright 2004 Elsevier B.V.

  17. Metabolic activity, urease production, antibiotic resistance and virulence in dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus

    Science.gov (United States)

    Vandecandelaere, Ilse; Van Nieuwerburgh, Filip; Deforce, Dieter

    2017-01-01

    In this paper, the metabolic activity in single and dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus isolates was investigated. Our results demonstrated that there was less metabolic activity in dual species biofilms compared to S. aureus biofilms. However, this was not observed if S. aureus and S. epidermidis were obtained from the same sample. The largest effect on metabolic activity was observed in biofilms of S. aureus Mu50 and S. epidermidis ET-024. A transcriptomic analysis of these dual species biofilms showed that urease genes and genes encoding proteins involved in metabolism were downregulated in comparison to monospecies biofilms. These results were subsequently confirmed by phenotypic assays. As metabolic activity is related to acid production, the pH in dual species biofilms was slightly higher compared to S. aureus Mu50 biofilms. Our results showed that S. epidermidis ET-024 in dual species biofilms inhibits metabolic activity of S. aureus Mu50, leading to less acid production. As a consequence, less urease activity is required to compensate for low pH. Importantly, this effect was biofilm-specific. Also S. aureus Mu50 genes encoding virulence-associated proteins (Spa, SplF and Dps) were upregulated in dual species biofilms compared to monospecies biofilms and using Caenorhabditis elegans infection assays, we demonstrated that more nematodes survived when co-infected with S. epidermidis ET-024 and S. aureus mutants lacking functional spa, splF or dps genes, compared to nematodes infected with S. epidermidis ET-024 and wild- type S. aureus. Finally, S. epidermidis ET-024 genes encoding resistance to oxacillin, erythromycin and tobramycin were upregulated in dual species biofilms and increased resistance was subsequently confirmed. Our data indicate that both species in dual species biofilms of S. epidermidis and S. aureus influence each other’s behavior, but additional studies are required necessary to elucidate the exact

  18. Norfloxacin monodose use in patients with cholera in Salta, Argentina El uso de monodosis de norfloxacina en pacientes con colera en Salta, Argentina

    Directory of Open Access Journals (Sweden)

    Alfredo César Seijo

    1996-06-01

    Full Text Available The use ofmonodose (800 mg per os of Norfloxacin was evaluated in 32 patients with cholera at Salvador Mazza's Hospital, Salta, Argentina. It was considered the celerity in negativization of stool culture (100% of cases: 12 hours post administration, its efficiency along time (24/24 controlled patients were negative at 10th day and MIC of isolated strains (100% of strains were sensitive: range 0.008 to 0.016 mug/ml. It was included oral administration of sorbitol 70% in peanut oil in order to study patients at 10th day's control. This method could be an alternative one in the study of asymptomatic carrier. Norfloxacin monodose shows good performance in early negativization of stool culture and it was also effective along the whole observation period, suggesting it could prevent carriage.Se evaluó el uso de monodosis (800 mg per os de Norfloxacina en 32 pacientes con cólera en el Hospital de Salvador Mazza, Salta, Argentina. Se consideró la rapidez en la negativización del coprocultivo (100% de los casos = 12 horas post administración, su eficacia a través del tiempo (24/24 pacientes controlados fueron negativos al 10° día y la CIM de las cepas aisladas (100% sensibles, rango 0.008 a 0.016 myg/ml. Para estudiar a los pacientes en el control del 10° día se incluyó la administración oral de sorbitol 70% en aceite de maní. Este método puede ser una alternativa en el estudio del portador asintomático. Norfloxacina en monodosis mostró buen desempeño en la pronta negativización del coprocultivo y fue también efectiva a lo largo de todo el período de observación sugiriendo que puede evitar la portación.

  19. Structure of polysaccharide antibiotics

    International Nuclear Information System (INIS)

    Matutano, L.

    1966-01-01

    Study of the structure of antibiotics having two or several sugars in their molecule. One may distinguish: the polysaccharide antibiotics themselves, made up of two or several sugars either with or without nitrogen, such as streptomycin, neomycins, paromomycine, kanamycin, chalcomycin; the hetero-polysaccharide antibiotics made up of one saccharide part linked to an aglycone of various type through a glucoside: macrolide, pigment, pyrimidine purine. Amongst these latter are: erythromycin, magnamycin, spiramycin, oleandomycin, cinerubin and amicetin. The sugars can either play a direct role in biochemical reactions or act as a dissolving agent, as far as the anti-microbe power of these antibiotics is concerned. (author) [fr

  20. Antibiotics: Miracle Drugs

    Centers for Disease Control (CDC) Podcasts

    2015-04-16

    The overuse of antibiotics has led to the development of resistance among bacteria, making antibiotics ineffective in treating certain conditions. This podcast discusses the importance of talking to your healthcare professional about whether or not antibiotics will be beneficial if you’ve been diagnosed with an infectious disease.  Created: 4/16/2015 by Division of Bacterial Diseases (DBD), National Center for Immunization and Respiratory Disease (NCIRD), Get Smart: Know When Antibiotics Work Program.   Date Released: 4/16/2015.

  1. Intracellular activity of antibiotics in a model of human THP-1 macrophages infected by a Staphylococcus aureus small-colony variant strain isolated from a cystic fibrosis patient: pharmacodynamic evaluation and comparison with isogenic normal-phenotype and revertant strains.

    Science.gov (United States)

    Nguyen, Hoang Anh; Denis, Olivier; Vergison, Anne; Theunis, Anne; Tulkens, Paul M; Struelens, Marc J; Van Bambeke, Françoise

    2009-04-01

    Small-colony variant (SCV) strains of Staphylococcus aureus show reduced antibiotic susceptibility and intracellular persistence, potentially explaining therapeutic failures. The activities of oxacillin, fusidic acid, clindamycin, gentamicin, rifampin, vancomycin, linezolid, quinupristin-dalfopristin, daptomycin, tigecycline, moxifloxacin, telavancin, and oritavancin have been examined in THP-1 macrophages infected by a stable thymidine-dependent SCV strain in comparison with normal-phenotype and revertant isogenic strains isolated from the same cystic fibrosis patient. The SCV strain grew slowly extracellularly and intracellularly (1- and 0.2-log CFU increase in 24 h, respectively). In confocal and electron microscopy, SCV and the normal-phenotype bacteria remain confined in acid vacuoles. All antibiotics tested, except tigecycline, caused a net reduction in bacterial counts that was both time and concentration dependent. At an extracellular concentration corresponding to the maximum concentration in human serum (total drug), oritavancin caused a 2-log CFU reduction at 24 h; rifampin, moxifloxacin, and quinupristin-dalfopristin caused a similar reduction at 72 h; and all other antibiotics had only a static effect at 24 h and a 1-log CFU reduction at 72 h. In concentration dependence experiments, response to oritavancin was bimodal (two successive plateaus of -0.4 and -3.1 log CFU); tigecycline, moxifloxacin, and rifampin showed maximal effects of -1.1 to -1.7 log CFU; and the other antibiotics produced results of -0.6 log CFU or less. Addition of thymidine restored intracellular growth of the SCV strain but did not modify the activity of antibiotics (except quinupristin-dalfopristin). All drugs (except tigecycline and oritavancin) showed higher intracellular activity against normal or revertant phenotypes than against SCV strains. The data may help rationalizing the design of further studies with intracellular SCV strains.

  2. Endophytes as sources of antibiotics.

    Science.gov (United States)

    Martinez-Klimova, Elena; Rodríguez-Peña, Karol; Sánchez, Sergio

    2017-06-15

    Until a viable alternative can be accessible, the emergence of resistance to antimicrobials requires the constant development of new antibiotics. Recent scientific efforts have been aimed at the bioprospecting of microorganisms' secondary metabolites, with special emphasis on the search for antimicrobial natural products derived from endophytes. Endophytes are microorganisms that inhabit the internal tissues of plants without causing apparent harm to the plant. The present review article compiles recent (2006-2016) literature to provide an update on endophyte research aimed at finding metabolites with antibiotic activities. We have included exclusively information on endophytes that produce metabolites capable of inhibiting the growth of bacterial, fungal and protozoan pathogens of humans, animals and plants. Where available, the identified metabolites have been listed. In this review, we have also compiled a list of the bacterial and fungal phyla that have been isolated as endophytes as well as the plant families from which the endophytes were isolated. The majority of endophytes that produce antibiotic metabolites belong to either phylum Ascomycota (kingdom Fungi) or to phylum Actinobacteria (superkingdom Bacteria). Endophytes that produce antibiotic metabolites were predominant, but certainly not exclusively, from the plant families Fabaceae, Lamiaceae, Asteraceae and Araceae, suggesting that endophytes that produce antimicrobial metabolites are not restricted to a reduced number of plant families. The locations where plants (and inhabiting endophytes) were collected from, according to the literature, have been mapped, showing that endophytes that produce bioactive compounds have been collected globally. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Detection of a wide variety of human and veterinary fluoroquinolone antibiotics in municipal wastewater and wastewater-impacted surface water.

    Science.gov (United States)

    He, Ke; Soares, Ana Dulce; Adejumo, Hollie; McDiarmid, Melissa; Squibb, Katherine; Blaney, Lee

    2015-03-15

    As annual sales of antibiotics continue to rise, the mass of these specially-designed compounds entering municipal wastewater treatment systems has also increased. Of primary concern here is that antibiotics can inhibit growth of specific microorganisms in biological processes of wastewater treatment plants (WWTPs) or in downstream ecosystems. Growth inhibition studies with Escherichia coli demonstrated that solutions containing 1-10 μg/L of fluoroquinolones can inhibit microbial growth. Wastewater samples were collected on a monthly basis from various treatment stages of a 30 million gallon per day WWTP in Maryland, USA. Samples were analyzed for the presence of 11 fluoroquinolone antibiotics. At least one fluoroquinolone was detected in every sample. Ofloxacin and ciprofloxacin exhibited detection frequencies of 100% and 98%, respectively, across all sampling sites. Concentrations of fluoroquinolones in raw wastewater were as high as 1900 ng/L for ciprofloxacin and 600 ng/L for ofloxacin. Difloxacin, enrofloxacin, fleroxacin, moxifloxacin, norfloxacin, and orbifloxacin were also detected at appreciable concentrations of 9-170 ng/L. The total mass concentration of fluoroquinolones in raw wastewater was in the range that inhibited E. coli growth, suggesting that concerns over antibiotic presence in wastewater and wastewater-impacted surface water are valid. The average removal efficiency of fluoroquinolones during wastewater treatment was approximately 65%; furthermore, the removal efficiency for fluoroquinolones was found to be negatively correlated to biochemical oxygen demand removal and positively correlated to phosphorus removal. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. LL-37-derived short antimicrobial peptide KR-12-a5 and its d-amino acid substituted analogs with cell selectivity, anti-biofilm activity, synergistic effect with conventional antibiotics, and anti-inflammatory activity.

    Science.gov (United States)

    Kim, Eun Young; Rajasekaran, Ganesan; Shin, Song Yub

    2017-08-18

    KR-12-a5 is a 12-meric α-helical antimicrobial peptide (AMP) with dual antimicrobial and anti-inflammatory activities designed from human cathelicidin LL-37. We designed and synthesized a series of d-amino acid-substituted analogs of KR-12-a5 with the aim of developing novel α-helical AMPs that possess higher cell selectivity than KR-12-a5, while maintaining the anti-inflammatory activity. d-amino acid incorporation into KR-12-a5 induced a significant improvement in the cell selectivity by 2.6- to 13.6-fold as compared to KR-12-a5, while maintaining the anti-inflammatory activity. Among the three analogs, KR-12-a5 (6- D L) with d-amino acid in the polar-nonpolar interface (Leu 6 ) showed the highest cell selectivity (therapeutic index: 61.2). Similar to LL-37, KR-12-a5 and its analogs significantly inhibited the expression and secretion of NO, TNF-α, IL-6 and MCP-1 from LPS-stimulated RAW264.7 cells. KR-12-a5 and its analogs showed a more potent antimicrobial activity against antibiotic-resistant bacteria, including clinically isolated MRSA, MDRPA, and VREF than LL-37 and melittin. Furthermore, compared to LL-37, KR-12-a5 and its analogs showed greater synergistic effects with conventional antibiotics, such as chloramphenicol, ciprofloxacin, and oxacillin against MDRPA; KR-12-a5 and its analogs had a FICI range between 0.25 and 0.5, and LL-37 had a range between 0.75 and 1.5. KR-12-a5 and its analogs were found to be more effective anti-biofilm agents against MDRPA than LL-37. In addition, KR-12-a5 and its analogs maintained antimicrobial activity in physiological salts and human serum. SYTOX Green uptake and membrane depolarization studies revealed that KR-12-a5 and its analogs kills microbial cells by permeabilizing the cell membrane and damaging membrane integrity. Taken together, our results suggest that KR-12-a5 and its analogs can be developed further as novel antimicrobial/anti-inflammatory agents to treat antibiotic-resistant infections. Copyright

  5. Hybrid antibiotics - clinical progress and novel designs.

    Science.gov (United States)

    Parkes, Alastair L; Yule, Ian A

    2016-07-01

    There is a growing need for new antibacterial agents, but success in development of antibiotics in recent years has been limited. This has led researchers to investigate novel approaches to finding compounds that are effective against multi-drug resistant bacteria, and that delay onset of resistance. One such strategy has been to link antibiotics to produce hybrids designed to overcome resistance mechanisms. The concept of dual-acting hybrid antibiotics was introduced and reviewed in this journal in 2010. In the present review the authors sought to discover how clinical candidates described had progressed, and to examine how the field has developed. In three sections the authors cover the clinical progress of hybrid antibiotics, novel agents produced from hybridisation of two or more small-molecule antibiotics, and novel agents produced from hybridisation of antibiotics with small-molecules that have complementary activity. Many key questions regarding dual-acting hybrid antibiotics remain to be answered, and the proposed benefits of this approach are yet to be demonstrated. While Cadazolid in particular continues to progress in the clinic, suggesting that there is promise in hybridisation through covalent linkage, it may be that properties other than antibacterial activity are key when choosing a partner molecule.

  6. Coping with antibiotic resistance: combining nanoparticles with antibiotics and other antimicrobial agents.

    Science.gov (United States)

    Allahverdiyev, Adil M; Kon, Kateryna Volodymyrivna; Abamor, Emrah Sefik; Bagirova, Malahat; Rafailovich, Miriam

    2011-11-01

    The worldwide escalation of bacterial resistance to conventional medical antibiotics is a serious concern for modern medicine. High prevalence of multidrug-resistant bacteria among bacteria-based infections decreases effectiveness of current treatments and causes thousands of deaths. New improvements in present methods and novel strategies are urgently needed to cope with this problem. Owing to their antibacterial activities, metallic nanoparticles represent an effective solution for overcoming bacterial resistance. However, metallic nanoparticles are toxic, which causes restrictions in their use. Recent studies have shown that combining nanoparticles with antibiotics not only reduces the toxicity of both agents towards human cells by decreasing the requirement for high dosages but also enhances their bactericidal properties. Combining antibiotics with nanoparticles also restores their ability to destroy bacteria that have acquired resistance to them. Furthermore, nanoparticles tagged with antibiotics have been shown to increase the concentration of antibiotics at the site of bacterium-antibiotic interaction, and to facilitate binding of antibiotics to bacteria. Likewise, combining nanoparticles with antimicrobial peptides and essential oils generates genuine synergy against bacterial resistance. In this article, we aim to summarize recent studies on interactions between nanoparticles and antibiotics, as well as other antibacterial agents to formulate new prospects for future studies. Based on the promising data that demonstrated the synergistic effects of antimicrobial agents with nanoparticles, we believe that this combination is a potential candidate for more research into treatments for antibiotic-resistant bacteria.

  7. Genetic Mechanisms of Antibiotic Resistance and the Role of Antibiotic Adjuvants.

    Science.gov (United States)

    Pontes, Daniela Santos; de Araujo, Rodrigo Santos Aquino; Dantas, Natalina; Scotti, Luciana; Scotti, Marcus Tullius; de Moura, Ricardo Olimpio; Mendonca-Junior, Francisco Jaime Bezerra

    2018-01-01

    The ever increasing number of multidrug-resistant microorganism pathogens has become a great and global public health threat. Antibiotic mechanisms of action and the opposing mechanisms of resistance are intimately associated, but comprehension of the biochemical and molecular functions of such drugs is not a simple exercise. Both the environment, and genetic settings contribute to alterations in phenotypic resistance (natural bacterial evolution), and make it difficult to control the emergence and impacts of antibiotic resistance. Under such circumstances, comprehension of how bacteria develop and/or acquire antibiotic resistance genes (ARG) has a critical role in developing propositions to fight against these superbugs, and to search for new drugs. In this review, we present and discuss both general information and examples of common genetic and molecular mechanisms related to antibiotic resistance, as well as how the expression and interactions of ARGs are important to drug resistance. At the same time, we focus on the recent achievements in the search for antibiotic adjuvants, which help combat antibiotic resistance through deactivation of bacterial mechanisms of action such as β-lactamases. Recent advances involving the use of anti-resistance drugs such as: efflux pump inhibitors; anti-virulence drugs; drugs against quorum sensing; and against type II/III secretion systems are revealed. Such antibiotic adjuvants (as explored herein) collaborate against the problems of antibiotic resistance, and may restore or prolong the therapeutic activity of known antibiotics. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. A study of the catalytic role of a gold electrode in the electrochemical activation of four macrolide antibiotics in sodium bicarbonate solution

    Directory of Open Access Journals (Sweden)

    Milka L. Avramov Ivić

    2010-07-01

    Full Text Available Using the cyclic voltammetry, it has been shown that hydrogen evolution at a gold electrode is necessary in the electrochemical activation of azithromycin dihydrate and erythromycin A. After four hours of the potential holding at –1.2 V vs. SCE, the pH of the electrolyte has been changed from 8.40 to 8.96; from 8.40 to 8.77 in the presence of erythromycin A, and from 8.40 to 9.18 in the presence of azithromycin, indicating the reaction of the hydrogen species with antibiotics. This effect has been confirmed by using the phenolphthalein indicator and by analysing colours of the solutions by UV-Vis, as well as by FTIR spectroscopy. Under the identical experimental conditions at the gold electrode, in contrast to azithromycin dihydrate and erythromycin A, roxithromycin and midecamycin electroactivity promotion has been obtained during the first forward sweep starting from the area of a double layer region.

  9. Handling Time-dependent Variables : Antibiotics and Antibiotic Resistance

    NARCIS (Netherlands)

    Munoz-Price, L. Silvia; Frencken, Jos F.; Tarima, Sergey; Bonten, Marc

    2016-01-01

    Elucidating quantitative associations between antibiotic exposure and antibiotic resistance development is important. In the absence of randomized trials, observational studies are the next best alternative to derive such estimates. Yet, as antibiotics are prescribed for varying time periods,

  10. Incidence and transferability of antibiotic resistance in the enteric bacteria isolated from hospital wastewater

    Directory of Open Access Journals (Sweden)

    Mohammad Zubair Alam

    2013-09-01

    Full Text Available This study reports the occurrence of antibiotic resistance and production of β-lactamases including extended spectrum beta-lactamases (ESβL in enteric bacteria isolated from hospital wastewater. Among sixty-nine isolates, tested for antibiotic sensitivity, 73.9% strains were resistant to ampicillin followed by nalidixic acid (72.5%, penicillin (63.8%, co-trimoxazole (55.1%, norfloxacin (53.6%, methicillin (52.7%, cefuroxime (39.1%, cefotaxime (23.2% and cefixime (20.3%. Resistance to streptomycin, chloramphenicol, nitrofurantoin, tetracycline, and doxycycline was recorded in less than 13% of the strains. The minimum inhibitory concentration (MIC showed a high level of resistance (800-1600 µg/mL to one or more antibiotics. Sixty three (91% isolates produced β-lactamases as determined by rapid iodometric test. Multiple antibiotic resistances were noted in both among ESβL and non-ESβL producers. The β-lactamases hydrolyzed multiple substrates including penicillin (78.8% isolates, ampicillin (62.3%, cefodroxil (52.2%, cefotoxime (21.7% and cefuroxime (18.8%. Fifteen isolates producing ESβLs were found multidrug resistant. Four ESβL producing isolates could transfer their R-plasmid to the recipient strain E. coli K-12 with conjugation frequency ranging from 7.0 x 10-3 to 8.8 x 10-4. The findings indicated that ESβL producing enteric bacteria are common in the waste water. Such isolates may disseminate the multiple antibiotic resistance traits among bacterial community through genetic exchange mechanisms and thus requires immediate attention.

  11. Incidence and transferability of antibiotic resistance in the enteric bacteria isolated from hospital wastewater

    Science.gov (United States)

    Alam, Mohammad Zubair; Aqil, Farrukh; Ahmad, Iqbal; Ahmad, Shamim

    2013-01-01

    This study reports the occurrence of antibiotic resistance and production of β-lactamases including extended spectrum beta-lactamases (ESβL) in enteric bacteria isolated from hospital wastewater. Among sixty-nine isolates, tested for antibiotic sensitivity, 73.9% strains were resistant to ampicillin followed by nalidixic acid (72.5%), penicillin (63.8%), co-trimoxazole (55.1%), norfloxacin (53.6%), methicillin (52.7%), cefuroxime (39.1%), cefotaxime (23.2%) and cefixime (20.3%). Resistance to streptomycin, chloramphenicol, nitrofurantoin, tetracycline, and doxycycline was recorded in less than 13% of the strains. The minimum inhibitory concentration (MIC) showed a high level of resistance (800–1600 μg/mL) to one or more antibiotics. Sixty three (91%) isolates produced β-lactamases as determined by rapid iodometric test. Multiple antibiotic resistances were noted in both among ESβL and non-ESβL producers. The β-lactamases hydrolyzed multiple substrates including penicillin (78.8% isolates), ampicillin (62.3%), cefodroxil (52.2%), cefotoxime (21.7%) and cefuroxime (18.8%). Fifteen isolates producing ESβLs were found multidrug resistant. Four ESβL producing isolates could transfer their R-plasmid to the recipient strain E. coli K-12 with conjugation frequency ranging from 7.0 × 10−3 to 8.8 × 10−4. The findings indicated that ESβL producing enteric bacteria are common in the waste water. Such isolates may disseminate the multiple antibiotic resistance traits among bacterial community through genetic exchange mechanisms and thus requires immediate attention. PMID:24516448

  12. Activities of beta-lactam antibiotics against Escherichia coli strains producing extended-spectrum beta-lactamases.

    Science.gov (United States)

    Jacoby, G A; Carreras, I

    1990-01-01

    Seven extended-spectrum beta-lactamases related to TEM and four enzymes derived from SHV-1 were transferred to a common Escherichia coli host so that the activity of a variety of beta-lactams could be tested in a uniform genetic environment. For most derivatives, penicillinase activity was 10% or less than that of strains making TEM-1, TEM-2, or SHV-1 beta-lactamase, suggesting that reduced catalytic efficiency accompanied the broader substrate spectrum. Despite this deficit, resistance to aztreonam, carumonam, cefdinir, cefepime, cefixime, cefmenoxime, cefotaxime, cefotiam, cefpirome, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefuroxime, and E1040 was enhanced. For strains producing TEM-type enzymes, however, MICs of carumonam, cefepime, cefmenoxime, cefotiam, cefpirome, and ceftibuten were 8 micrograms/ml or less. Susceptibilities of cefmetazole, cefotetan, cefoxitin, flomoxef, imipenem, meropenem, moxalactam, temocillin, FCE 22101, and Sch 34343 were unaffected. FCE 22101, imipenem, meropenem, and Sch 34343 were inhibitory for all strains at 1 microgram/ml or less. In E. coli an OmpF- porin mutation in combination with an extended-spectrum beta-lactamase enhanced resistance to many of these agents, but generally by only fourfold. Hyperproduction of chromosomal AmpC beta-lactamase increased resistance to 7-alpha-methoxy beta-lactams but not that to temocillin. When tested at 8 micrograms/ml, clavulanate was more potent than sulbactam or tazobactam in overcoming resistance to ampicillin, while cefoperazone-sulbactam was more active than ticarcillin-clavulanate or piperacillin-tazobactam, especially against TEM-type extended-spectrum beta-lactamases. PMID:2193623

  13. Reductive methods for isotopic labeling of antibiotics

    International Nuclear Information System (INIS)

    Champney, W.S.

    1989-01-01

    Methods for the reductive methylation of the amino groups of eight different antibiotics using 3 HCOH or H 14 COH are presented. The reductive labeling of an additional seven antibiotics by NaB 3 H 4 is also described. The specific activity of the methyl-labeled drugs was determined by a phosphocellulose paper binding assay. Two quantitative assays for these compounds based on the reactivity of the antibiotic amino groups with fluorescamine and of the aldehyde and ketone groups with 2,4-dinitrophenylhydrazine are also presented. Data on the cellular uptake and ribosome binding of these labeled compounds are also presented

  14. Dynamics induced by β-lactam antibiotics in the active site of Bacillus subtilis L,D-transpeptidase.

    Science.gov (United States)

    Lecoq, Lauriane; Bougault, Catherine; Hugonnet, Jean-Emmanuel; Veckerlé, Carole; Pessey, Ombeline; Arthur, Michel; Simorre, Jean-Pierre

    2012-05-09

    β-lactams inhibit peptidoglycan polymerization by acting as suicide substrates of essential d,d-transpeptidases. Bypass of these enzymes by unrelated l,d-transpeptidases results in β-lactam resistance, although carbapenems remain unexpectedly active. To gain insight into carbapenem specificity of l,d-transpeptidases (Ldts), we solved the nuclear magnetic resonance (NMR) structures of apo and imipenem-acylated Bacillus subtilis Ldt and show that the cysteine nucleophile is present as a neutral imidazole-sulfhydryl pair in the substrate-free enzyme. NMR relaxation dispersion does not reveal any preexisting conformational exchange in the apoenzyme, and change in flexibility is not observed upon noncovalent binding of β-lactams (K(D) > 37.5 mM). In contrast, covalent modification of active cysteine by both carbapenems and 2-nitro-5-thiobenzoate induces backbone flexibility that does not result from disruption of the imidazole-sulfhydryl proton interaction or steric hindrance. The chemical step of the reaction determines enzyme specificity since no differences in drug affinity were observed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Staphylococcus aureus Alters Growth Activity, Autolysis, and Antibiotic Tolerance in a Human Host-Adapted Pseudomonas aeruginosa Lineage

    DEFF Research Database (Denmark)

    Frydenlund Michelsen, Charlotte; Christensen, Anne-Mette; Bojer, Martin Saxtorph

    2014-01-01

    Interactions among members of polymicrobial infections or between pathogens and the commensal flora may determine disease outcomes. Pseudomonas aeruginosa and Staphylococcus aureus are important opportunistic human pathogens and are both part of the polymicrobial infection communities in human...... hosts. In this study, we analyzed the in vitro interaction between S. aureus and a collection of P. aeruginosa isolates representing different evolutionary steps of a dominant lineage, DK2, that have evolved through decades of growth in chronically infected patients. While the early adapted P....... aeruginosa DK2 strains outcompeted S. aureus during coculture on agar plates, we found that later P. aeruginosa DK2 strains showed a commensal-like interaction, where S. aureus was not inhibited by P. aeruginosa and the growth activity of P. aeruginosa was enhanced in the presence of S. aureus. This effect...

  16. [Antibiotics: present and future].

    Science.gov (United States)

    Bérdy, János

    2013-04-14

    The author discuss the up to date interpretation of the concept of antibiotics and antibiotic research, as well as the present role of various natural, semisynthetic and synthetic antibiotic compounds in various areas of the human therapy. The origin and the total number of all antibiotics and applied antibiotics in the practice, as well as the bioactive microbial metabolites (antibiotics) in other therapeutical, non-antibiotic fields (including agriculture) are also reviewed. The author discusses main problems, such as increasing (poly)resistance, virulence of pathogens and the non-scientific factors (such as a decline of research efforts and their sociological, economic, financial and regulatory reasons). A short summary of the history of Hungarian antibiotic research is also provided. The author briefly discusses the prospects in the future and the general advantages of the natural products over synthetic compounds. It is concluded that new approaches for the investigation of the unlimited possibilities of the living world are necessary. The discovery of new types or simply neglected (micro)organisms and their biosynthetic capabilities, the introduction of new biotechnological and genetic methods (genomics, metagenom, genome mining) are absolutely required in the future.

  17. The future of antibiotics

    Science.gov (United States)

    2014-01-01

    Antibiotic resistance continues to spread even as society is experiencing a market failure of new antibiotic research and development (R&D). Scientific, economic, and regulatory barriers all contribute to the antibiotic market failure. Scientific solutions to rekindle R&D include finding new screening strategies to identify novel antibiotic scaffolds and transforming the way we think about treating infections, such that the goal is to disarm the pathogen without killing it or modulate the host response to the organism without targeting the organism for destruction. Future economic strategies are likely to focus on ‘push’ incentives offered by public-private partnerships as well as increasing pricing by focusing development on areas of high unmet need. Such strategies can also help protect new antibiotics from overuse after marketing. Regulatory reform is needed to re-establish feasible and meaningful traditional antibiotic pathways, to create novel limited-use pathways that focus on highly resistant infections, and to harmonize regulatory standards across nations. We need new antibiotics with which to treat our patients. But we also need to protect those new antibiotics from misuse when they become available. If we want to break the cycle of resistance and change the current landscape, disruptive approaches that challenge long-standing dogma will be needed. PMID:25043962

  18. Antibiotics in Canadian poultry productions and anticipated alternatives

    Directory of Open Access Journals (Sweden)

    Moussa Sory Diarra

    2014-06-01

    Full Text Available The use of antibiotics in food-producing animals has significantly increased animal health by lowering mortality and the incidence of diseases. Antibiotics also have largely contributed to increase productivity of farms. However, antibiotic usage in general and relevance of non-therapeutic antibiotics in feed (growth promoters need to be reevaluated especially because bacterial pathogens of humans and animals have developed and shared a variety of antibiotic resistance mechanisms that can easily spread within microbial communities. In Canada, poultry production involves more than 2,600 regulated chicken producers. There are several antibiotics approved as feed additives available for poultry farmers. Feed recipes and mixtures greatly vary geographically and from one farm to another, making links between use of a specific antibiotic feed additive and production yields or selection of specific antibiotic-resistant bacteria difficult to establish. Many on-farm studies have revealed the widespread presence of antibiotic-resistant bacteria in broiler chickens. While sporadic reports linked the presence of antibiotic-resistant organisms to the use of feed supplemented with antibiotics, no recent studies could clearly demonstrate the benefit of antimicrobial growth promoters on performance and production yields. With modern biosecurity and hygienic practices, there is a genuine concern that intensive utilization of antibiotics or use of antimicrobial growth promoters in feed might no longer be useful. Public pressure and concerns about food and environmental safety (antibiotic residues, antibiotic-resistant pathogens have driven researchers to actively look for alternatives to antibiotics. Some of the alternatives include pre- and probiotics, organic acids and essential oils. We will describe here the properties of some bioactive molecules, like those found in cranberry, which have shown interesting polyvalent antibacterial and immuno

  19. Designing Safer and Greener Antibiotics

    Directory of Open Access Journals (Sweden)

    Nicholas Gathergood

    2013-09-01

    Full Text Available Since the production of the first pharmaceutically active molecules at the beginning of the 1900s, drug molecules and their metabolites have been observed in the environment in significant concentrations. In this review, the persistence of antibiotics in the environment and their associated effects on ecosystems, bacterial resistance and health effects will be examined. Solutions to these problems will also be discussed, including the pharmaceutical industries input, green chemistry, computer modeling and representative ionic liquid research.

  20. In vitro susceptibility of aural isolates of Pseudomonas aeruginosa to commonly used ototopical antibiotics.

    Science.gov (United States)

    Dohar, J E; Kenna, M A; Wadowsky, R M

    1996-03-01

    The choice of antimicrobial agents used to treat Pseudomonas aeruginosa infections of the ear is quite empiric. Yet in spite of this, very little has been published examining susceptibility patterns of aural isolates of P. aeruginosa. Recently, increasing concern has emerged over the development of resistance to many of the commonly used ototopical preparations with activity against P. aeruginosa. This concern stems from the fact that these preparations have been in use for a long time, and P. aeruginosa is known to develop resistance fairly readily. We prospectively studied the susceptibilities of aural isolates of P. aeruginosa in 231 consecutive children who were seen in the outpatient Pediatric Otolaryngology Department at Children's Hospital of Pittsburgh during the years 1992 and 1993. The agents tested included neomycin, polymyxin B, colistin, and norfloxacin. We found that only 17.8% of the isolates were sensitive to neomycin, as opposed to > 95% for each of the other agents tested (polymyxin B, 99.6%; colistin, 97.4%; and norfloxacin, 98.3%). This difference proved to be statistically significant (p < 0.05). Given the concern of aminoglycoside-induced ototoxicity and the high rate of neomycin resistance, we believe that further investigation of other alternative ototopic agents with activity against P. aeruginosa is warranted.

  1. Antibacterial activity and mechanism of Ag-ZnO nanocomposite on S. aureus and GFP-expressing antibiotic resistant E. coli.

    Science.gov (United States)

    Matai, Ishita; Sachdev, Abhay; Dubey, Poornima; Kumar, S Uday; Bhushan, Bharat; Gopinath, P

    2014-03-01

    Emergence of multi-resistant organisms (MROs) leads to ineffective treatment with the currently available medications which pose a great threat to public health and food technology sectors. In this regard, there is an urgent need to strengthen the present therapies or to look over for other potential alternatives like use of "metal nanocomposites". Thus, the present study focuses on synthesis of silver-zinc oxide (Ag-ZnO) nanocomposites which will have a broad-spectrum antibacterial activity against Gram-positive and Gram-negative bacteria. Ag-ZnO nanocomposites of varied molar ratios were synthesized by simple microwave assisted reactions in the absence of surfactants. The crystalline behavior, composition and morphological analysis of the prepared powders were evaluated by X-ray diffraction, infrared spectroscopy, field emission scanning electron microscopy (FE-SEM) and atomic absorption spectrophotometry (AAS). Particle size measurements were carried out by transmission electron microscopy (TEM). Staphylococcus aureus and recombinant green fluorescent protein (GFP) expressing antibiotic resistant Escherichia coli were selected as Gram-positive and Gram-negative model systems respectively and the bactericidal activity of Ag-ZnO nanocomposite was studied. The minimum inhibitory concentration (MIC) and minimum killing concentration (MKC) of the nanocomposite against the model systems were determined by visual turbidity analysis and optical density analysis. Qualitative and quantitative assessments of its antibacterial effects were performed by fluorescent microscopy, fluorescent spectroscopy and Gram staining measurements. Changes in cellular morphology were examined by atomic force microscopy (AFM), FE-SEM and TEM. Finally, on the basis of the present investigation and previously published reports, a plausible antibacterial mechanism of Ag-ZnO nanocomposites was proposed. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Antibiotic rezistance genes in soil actinobacteria

    OpenAIRE

    Patrmanová, Tereza

    2016-01-01

    Actinobacteria are important members of the soil ecosystems, where they are involved in organic matter decomposition. It is worth mentioning that their secondary metabolism allows them to produce a variety of different compounds. These compounds include antibiotics, among them aminoglycosides have a place in clinical practice. These antibiotics are significant due to a broad spectrum of activities against both gram-negative and gram-positive bacteria. However, their use currently carries a ri...

  3. Molecular Regulation of Antibiotic Biosynthesis in Streptomyces

    Science.gov (United States)

    Liu, Gang; Chandra, Govind; Niu, Guoqing

    2013-01-01

    SUMMARY Streptomycetes are the most abundant source of antibiotics. Typically, each species produces several antibiotics, with the profile being species specific. Streptomyces coelicolor, the model species, produces at least five different antibiotics. We review the regulation of antibiotic biosynthesis in S. coelicolor and other, nonmodel streptomycetes in the light of recent studies. The biosynthesis of each antibiotic is specified by a large gene cluster, usually including regulatory genes (cluster-situated regulators [CSRs]). These are the main point of connection with a plethora of generally conserved regulatory systems that monitor the organism's physiology, developmental state, population density, and environment to determine the onset and level of production of each antibiotic. Some CSRs may also be sensitive to the levels of different kinds of ligands, including products of the pathway itself, products of other antibiotic pathways in the same organism, and specialized regulatory small molecules such as gamma-butyrolactones. These interactions can result in self-reinforcing feed-forward circuitry and complex cross talk between pathways. The physiological signals and regulatory mechanisms may be of practical importance for the activation of the many cryptic secondary metabolic gene cluster pathways revealed by recent sequencing of numerous Streptomyces genomes. PMID:23471619

  4. Temporal–spatial variation and partitioning prediction of antibiotics in surface water and sediments from the intertidal zones of the Yellow River Delta, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shengnan [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Liu, Xinhui, E-mail: xhliu@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Cheng, Dengmiao [Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture, Beijing 100081 (China); Liu, Guannan [MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, CAGS, Beijing 100037 (China); Liang, Baocui; Cui, Baoshan; Bai, Junhong [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China)

    2016-11-01

    As special zones, the intertidal zones of the Yellow River Delta (YRD) are highly variable along with time and space. Fluvial–marine and land–ocean interactions which frequently occur in these areas have a great impact on the fate of pollutants. Antibiotics, which contribute to antibiotic-resistant genes (ARGs), are widely detected in wastewater, natural water, soil, sediments, and even drinking water. Therefore, it is meaningful to investigate the occurrence and fate of antibiotics in these special zones. In this study, eight antibiotics belonging to tetracyclines (TCs), fluoroquinolones (FQs), and macrolides (MLs) were detected in the surface water and sediments from the intertidal zones of YRD during two seasons. Two models were established to predict the partitioning coefficients of norfloxacin (NOR) and erythromycin (ETM) using physicochemical properties of sediments, respectively. The total concentrations of these antibiotics were 82.94–230.96 ng·L{sup −} {sup 1} and 40.97–207.44 ng·g{sup −} {sup 1}, respectively, in the surface water and sediments. Seasonal variation was mainly influenced by the frequency of antibiotics use and environment factors. The regions with river supply exhibited the highest concentrations of antibiotics in surface water and sediments. Meanwhile, particle-size fractions, cation exchange capability (CEC), and metal ions content played dominant roles in the partitioning behaviors of NOR and ETM between the surface water and sediments. Both models established in this study featured accuracy and feasibility, which provided the methods for predicting the partitioning coefficients of emerging contaminants similar in structures to NOR and ETM in the intertidal zones. - Highlights: • The intertidal zones of YRD were polluted by antibiotics to some extent. • The river supply was a major pathway for the antibiotic pollution of the intertidal zones of YRD. • The partitioning coefficients of NOR and ETM can be predicted using

  5. Temporal–spatial variation and partitioning prediction of antibiotics in surface water and sediments from the intertidal zones of the Yellow River Delta, China

    International Nuclear Information System (INIS)

    Zhao, Shengnan; Liu, Xinhui; Cheng, Dengmiao; Liu, Guannan; Liang, Baocui; Cui, Baoshan; Bai, Junhong

    2016-01-01

    As special zones, the intertidal zones of the Yellow River Delta (YRD) are highly variable along with time and space. Fluvial–marine and land–ocean interactions which frequently occur in these areas have a great impact on the fate of pollutants. Antibiotics, which contribute to antibiotic-resistant genes (ARGs), are widely detected in wastewater, natural water, soil, sediments, and even drinking water. Therefore, it is meaningful to investigate the occurrence and fate of antibiotics in these special zones. In this study, eight antibiotics belonging to tetracyclines (TCs), fluoroquinolones (FQs), and macrolides (MLs) were detected in the surface water and sediments from the intertidal zones of YRD during two seasons. Two models were established to predict the partitioning coefficients of norfloxacin (NOR) and erythromycin (ETM) using physicochemical properties of sediments, respectively. The total concentrations of these antibiotics were 82.94–230.96 ng·L"− "1 and 40.97–207.44 ng·g"− "1, respectively, in the surface water and sediments. Seasonal variation was mainly influenced by the frequency of antibiotics use and environment factors. The regions with river supply exhibited the highest concentrations of antibiotics in surface water and sediments. Meanwhile, particle-size fractions, cation exchange capability (CEC), and metal ions content played dominant roles in the partitioning behaviors of NOR and ETM between the surface water and sediments. Both models established in this study featured accuracy and feasibility, which provided the methods for predicting the partitioning coefficients of emerging contaminants similar in structures to NOR and ETM in the intertidal zones. - Highlights: • The intertidal zones of YRD were polluted by antibiotics to some extent. • The river supply was a major pathway for the antibiotic pollution of the intertidal zones of YRD. • The partitioning coefficients of NOR and ETM can be predicted using the physicochemical

  6. Adaption of the microbial community to continuous exposures of multiple residual antibiotics in sediments from a salt-water aquacultural farm.

    Science.gov (United States)

    Xi, Xiuping; Wang, Min; Chen, Yongshan; Yu, Shen; Hong, Youwei; Ma, Jun; Wu, Qian; Lin, Qiaoyin; Xu, Xiangrong

    2015-06-15

    Residual antibiotics from aquacultural farming may alter microbial community structure in aquatic environments in ways that may adversely or positively impact microbially-mediated ecological functions. This study investigated 26 ponds (26 composited samples) used to produce fish, razor clam and shrimp (farming and drying) and 2 channels (10 samples) in a saltwater aquacultural farm in southern China to characterize microbial community structure (represented by phospholipid fatty acids) in surface sediments (0-10 cm) with long-term exposure to residual antibiotics. 11 out of 14 widely-used antibiotics were quantifiable at μg kg(-1) levels in sediments but their concentrations did not statistically differ among ponds and channels, except norfloxacin in drying shrimp ponds and thiamphenicol in razor clam ponds. Concentrations of protozoan PLFAs were significantly increased in sediments from razor clam ponds while other microbial groups were similar among ponds and channels. Both canonical-correlation and stepwise-multiple-regression analyses on microbial community and residual antibiotics suggested that roxithromycin residuals were significantly related to shifts in microbial community structure in sediments. This study provided field evidence that multiple residual antibiotics at low environmental levels from aquacultural farming do not produce fundamental shifts in microbial community structure. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. [REDUCTION OF ANTIBIOTIC CONSUMPTION IN RAMBAM HEALTH CARE CAMPUS - THE ROLE OF AN ANTIBIOTIC STEWARDSHIP PROGRAM].

    Science.gov (United States)

    Bitterman, Roni; Raz-Pasteur, Ayelet; Azzam, Zaher S; Karban, Amir; Levy, Yishai; Hayek, Tony; Braun, Eyal; Oren, Ilana; Bar-Lavi, Yaron; Kassis, Imad; Hussein, Khetam; Paul, Mical

    2017-09-01

    Antibiotic stewardship programs (ASP) are designed to optimize antibiotic use in hospitals. Antibiotic consumption is one of the measures assessing the effects of ASPs. To evaluate the effect of an ASP on antibiotic consumption in our hospital and compare it to hospitals in Israel and worldwide. Between October 2012 and March 2013 an ASP was implemented in Rambam Hospital. The program included educational activities, publication of local guidelines for empirical antibiotic treatment, structured infectious diseases consultations, pre-authorization antibiotic restrictions and stop orders. We compared antibacterial antibiotic consumption in defined daily doses (DDD)/100 hospital days (HD) between the periods before (1/2010-3/2013) and after (4/2013-9/2014) implementing the ASP. The study was conducted in the medical departments, hematology, the intensive care unit (ICU) and all pediatric wards. Total antibiotic consumption before implementing the ASP was 96±11.2 DDD/100 HD in medical departments, 186.4±42.8 in the ICU and 185.5±59 in hematology; all values were higher than the worldwide-reported averages for these departments. Following the ASP, total antibiotic consumption decreased by 12% (p=0.008) in the medical departments and by 26% (p=0.002) in hematology, mostly due to reductions in non-restricted antibiotics. No significant changes were observed overall in the ICU and in pediatric wards. There was a significant reduction in consumption of vancomycin and carbapenems in all settings, the latter was reduced to nearly half. Amikacin use quadrupled in the medical departments. Implementation of an ASP lead to a reduction in non-restricted and restricted antibiotic consumption, especially carbapenems.

  8. Effect of the Association of Nonsteroidal Anti-inflammatory and Antibiotic Drugs on Antibiofilm Activity and pH of Calcium Hydroxide Pastes.

    Science.gov (United States)

    de Freitas, Rafaela Pignatti; Greatti, Vanessa Raquel; Alcalde, Murilo Priori; Cavenago, Bruno Cavalini; Vivan, Rodrigo Ricci; Duarte, Marco Antonio Hungaro; Weckwerth, Ana Carolina Villas Bôas; Weckwerth, Paulo Henrique

    2017-01-01

    The objective of the present study was to evaluate the in vitro antibiofilm activity and pH of calcium hydroxide associated with different nonsteroidal anti-inflammatory drugs (NSAIDs). The groups analyzed were as follows: group 1, calcium hydroxide paste with propylene glycol; group 2, calcium hydroxide paste with propylene glycol + 5% diclofenac sodium; group 3, calcium hydroxide paste with propylene glycol + 5% ibuprofen; group 4, calcium hydroxide paste with propylene glycol + 5% ciprofloxacin; and group 6, positive control (without medication). For analysis of the pH, the pastes were inserted into tubes and immersed in flasks containing ultrapure water. At the time intervals of 3, 24, 72, and 168 hours, the pH was measured with a calibrated pH meter. For microbial analysis, biofilm was induced in 30 bovine dentin blocks for 21 days. Subsequently, the pastes were placed on the blocks with biofilm for 7 days. Afterward, the pastes were removed by irrigation with sterile water, and the specimens were analyzed with a laser scanning confocal microscope with the 50 μL Live/Dead BacLight Bacterial Viability solution L7012 Kit (Molecular Probes, Inc, Eugene, OR). Data were subjected to statistical analysis at a significance level of 5%. The highest pH values were found for calcium hydroxide associated with ciprofloxacin in all periods analyzed. With the exception of pure calcium hydroxide paste, the other groups showed statistically significant differences (P antibiotic did not interfere with the pH of calcium hydroxide paste and increased the antimicrobial action of calcium hydroxide paste against Enterococcus faecalis biofilm formation. Published by Elsevier Inc.

  9. The effects of low-intensity electromagnetic irradiation at the frequencies of 51.8 and 53 GHz and antibiotic ceftazidime on Lactobacillus acidophilus F0F1 ATP-ase activity

    International Nuclear Information System (INIS)

    Soghomonyan, D.R.

    2013-01-01

    The effects of low intensity electromagnetic irradiation (EMI) at the frequencies 51.8 and 53 GHz and antibiotic ceftazidime on N,N'-dicyclohexylcarbodiimide (DCCD), inhibited ATP-ase activity of Lactobacillus acidophilus membrane vesicles were investigated. It was shown that both frequencies decreased the ATP-ase activity, moreover, ceftazidime increase the sensitivity of cells to DCCD, inhibitor of the F 0 F 1 -ATP-ase. EMI combined with ceftazidime and DCCD markedly decreased the ATPase activity. The F 0 F 1 -ATP-ase is suggested can be a target for the effects observed

  10. Addressing resistance to antibiotics in systematic reviews of antibiotic interventions

    NARCIS (Netherlands)

    Leibovici, Leonard; Paul, Mical; Garner, Paul; Sinclair, David J; Afshari, Arash; Pace, Nathan Leon; Cullum, Nicky; Williams, Hywel C; Smyth, Alan; Skoetz, Nicole; Del Mar, Chris; Schilder, Anne G M; Yahav, Dafna; Tovey, David

    Antibiotics are among the most important interventions in healthcare. Resistance of bacteria to antibiotics threatens the effectiveness of treatment. Systematic reviews of antibiotic treatments often do not address resistance to antibiotics even when data are available in the original studies. This

  11. Fighting antibiotic resistance in the intensive care unit using antibiotics.

    Science.gov (United States)

    Plantinga, Nienke L; Wittekamp, Bastiaan H J; van Duijn, Pleun J; Bonten, Marc J M

    2015-01-01

    Antibiotic resistance is a global and increasing problem that is not counterbalanced by the development of new therapeutic agents. The prevalence of antibiotic resistance is especially high in intensive care units with frequently reported outbreaks of multidrug-resistant organisms. In addition to classical infection prevention protocols and surveillance programs, counterintuitive interventions, such as selective decontamination with antibiotics and antibiotic rotation have been applied and investigated to control the emergence of antibiotic resistance. This review provides an overview of selective oropharyngeal and digestive tract decontamination, decolonization of methicillin-resistant Staphylococcus aureus and antibiotic rotation as strategies to modulate antibiotic resistance in the intensive care unit.

  12. Epidemiology of urinary tract infections and antibiotics sensitivity among pregnant women at Khartoum North Hospital

    Directory of Open Access Journals (Sweden)

    Ali Salah K

    2011-01-01

    Full Text Available Abstract Background Urinary tract infections (UTI can lead to poor maternal and perinatal outcomes. Investigating epidemiology of UTI and antibiotics sensitivity among pregnant women is fundamental for care-givers and health planners. Methods A cross sectional study has been conducted at Khartoum north teaching hospital Antenatal Care Clinic between February-June 2010, to investigate epidemiology of UTI and antibiotics resistance among pregnant women. Structured questionnaires were used to gather data from pregnant women. UTI was diagnosed using mid stream urine culture on standard culture media Results Out of 235 pregnant women included, 66 (28.0% were symptomatic and 169 (71.9% asymptomatic. the prevalence of bacteriuria among symptomatic and asymptomatic pregnant women were (12.1%, and (14.7% respectively, with no significant difference between the two groups (P = 0.596, and the overall prevalence of UTI was (14.0%. In multivariate analyses, age, gestational age, parity, and history of UTI in index pregnancy were not associated with bacteriuria. Escherichia coli (42.4% and S. aureus (39.3% were the commonest isolated bacteria. Four, 2, 2, 3, 4, 2 and 0 out of 14 E. coli isolates, showed resistance to amoxicillin, naladixic acid, nitrofurantoin, ciprofloxacin, co-trimoxazole, amoxicillin/clavulanate and norfloxacin, respectively Conclusion Escherichia coli were the most prevalent causative organisms and showing multi drug resistance pattern, asymptomatic bacteriuria is more prevalent than symptomatic among pregnant women. Urine culture for screening and diagnosis purpose for all pregnant is recommended.

  13. Epidemiology of urinary tract infections and antibiotics sensitivity among pregnant women at Khartoum North Hospital.

    Science.gov (United States)

    Hamdan, Hamdan Z; Ziad, Abdel Haliem M; Ali, Salah K; Adam, Ishag

    2011-01-18

    Urinary tract infections (UTI) can lead to poor maternal and perinatal outcomes. Investigating epidemiology of UTI and antibiotics sensitivity among pregnant women is fundamental for care-givers and health planners. A cross sectional study has been conducted at Khartoum north teaching hospital Antenatal Care Clinic between February-June 2010, to investigate epidemiology of UTI and antibiotics resistance among pregnant women. Structured questionnaires were used to gather data from pregnant women. UTI was diagnosed using mid stream urine culture on standard culture media Out of 235 pregnant women included, 66 (28.0%) were symptomatic and 169 (71.9%) asymptomatic. the prevalence of bacteriuria among symptomatic and asymptomatic pregnant women were (12.1%), and (14.7%) respectively, with no significant difference between the two groups (P = 0.596), and the overall prevalence of UTI was (14.0%). In multivariate analyses, age, gestational age, parity, and history of UTI in index pregnancy were not associated with bacteriuria. Escherichia coli (42.4%) and S. aureus (39.3%) were the commonest isolated bacteria. Four, 2, 2, 3, 4, 2 and 0 out of 14 E. coli isolates, showed resistance to amoxicillin, naladixic acid, nitrofurantoin, ciprofloxacin, co-trimoxazole, amoxicillin/clavulanate and norfloxacin, respectively. Escherichia coli were the most prevalent causative organisms and showing multi drug resistance pattern, asymptomatic bacteriuria is more prevalent than symptomatic among pregnant women. Urine culture for screening and diagnosis purpose for all pregnant is recommended.

  14. Antibiotic resistance and enterotoxin genes in Staphylococcus sp. isolates from polluted water in Southern Brazil.

    Science.gov (United States)

    Basso, Ana P; Martins, Paula D; Nachtigall, Gisele; Van Der Sand, Sueli; De Moura, Tiane M; Frazzon, Ana Paula G

    2014-12-01

    The aim of this study was to evaluate the species distribution, antibiotic-resistance profile and presence of enterotoxin (SE) genes in staphylococci isolated from the Dilúvio stream in South Brazil. Eighty-eight staphylococci were identified, 93.18% were identified as coagulase-negative (CNS) and 6.82% coagulase-positive (CPS). Fourteen Staphylococcus species were detected and the most frequently were Staphylococcus cohnii (30.48%) and S. haemolyticus (21.95%). Resistance to erythromycin was verified in 37.50% of the strains, followed by 27.27% to penicillin, 12.50% to clindamycin, 6.81% to trimethoprim-sulfamethoxazole, 5.68% to chloramphenicol and 2.27% to norfloxacin. None of the investigated strains showed gentamicin and ciprofloxacin resistance. The strains were tested for the presence of sea, seb, sec, sed and see genes by PCR and only CNS strains (43.18%) showed positive results to one or more SE genes. The scientific importance of our results is due to the lack of data about these topics in polluted waters in Brazil. In conclusion, polluted waters from the Dilúvio stream may constitute a reservoir for disseminating antibiotic-resistance and enterotoxin into the community. In addition, the detection of staphylococci in the polluted waters of the Dilúvio stream indicated a situation of environmental contamination and poor sanitation conditions.

  15. Antibiotic resistance and enterotoxin genes in Staphylococcus sp. isolates from polluted water in Southern Brazil

    Directory of Open Access Journals (Sweden)

    ANA P. BASSO

    2014-12-01

    Full Text Available The aim of this study was to evaluate the species distribution, antibiotic-resistance profile and presence of enterotoxin (SE genes in staphylococci isolated from the Dilúvio stream in South Brazil. Eighty-eight staphylococci were identified, 93.18% were identified as coagulase-negative (CNS and 6.82% coagulase-positive (CPS. Fourteen Staphylococcus species were detected and the most frequently were Staphylococcus cohnii (30.48% and S. haemolyticus (21.95%. Resistance to erythromycin was verified in 37.50% of the strains, followed by 27.27% to penicillin, 12.50% to clindamycin, 6.81% to trimethoprim-sulfamethoxazole, 5.68% to chloramphenicol and 2.27% to norfloxacin. None of the investigated strains showed gentamicin and ciprofloxacin resistance. The strains were tested for the presence of sea, seb, sec, sed and see genes by PCR and only CNS strains (43.18% showed positive results to one or more SE genes. The scientific importance of our results is due to the lack of data about these topics in polluted waters in Brazil. In conclusion, polluted waters from the Dilúvio stream may constitute a reservoir for disseminating antibiotic-resistance and enterotoxin into the community. In addition, the detection of staphylococci in the polluted waters of the Dilúvio stream indicated a situation of environmental contamination and poor sanitation conditions.

  16. Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H{sub 2}O{sub 2} and Na{sub 2}S{sub 2}O{sub 8} under UV-254 nm irradiation

    Energy Technology Data Exchange (ETDEWEB)

    He, Xuexiang [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Department of Civil and Environmental Engineering and Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678 Nicosia (Cyprus); Mezyk, Stephen P. [Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840 (United States); Michael, Irene; Fatta-Kassinos, Despo [Department of Civil and Environmental Engineering and Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678 Nicosia (Cyprus); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Department of Civil and Environmental Engineering and Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678 Nicosia (Cyprus)

    2014-08-30

    Graphical abstract: - Highlights: • Removal efficiency was comparable at different UV fluence rates but same fluence. • Reducing pH to 3 or 2 did not inhibit the removal of nitrobenzene by UV/S{sub 2}O{sub 8}{sup 2−}. • 1.84 × 10{sup −14} M [HO{sup •} ]{sub ss} and 3.10 × 10{sup −13} M [SO{sub 4}{sup •} {sup −}]{sub ss} in UV/S{sub 2}O{sub 8}{sup 2−} were estimated. • HO{sup •} reacted faster with the β-lactams than SO{sub 4}{sup •} {sup −} but sharing similar byproducts. • Transformation pathways included hydroxylation, hydrolysis and decarboxylation. - Abstract: The extensive production and usage of antibiotics have led to an increasing occurrence of antibiotic residuals in various aquatic compartments, presenting a significant threat to both ecosystem and human health. This study investigated the degradation of selected β-lactam antibiotics (penicillins: ampicillin, penicillin V, and piperacillin; cephalosporin: cephalothin) by UV-254 nm activated H{sub 2}O{sub 2} and S{sub 2}O{sub 8}{sup 2−} photochemical processes. The UV irradiation alone resulted in various degrees of direct photolysis of the antibiotics; while the addition of the oxidants improved significantly the removal efficiency. The steady-state radical concentrations were estimated, revealing a non-negligible contribution of hydroxyl radicals in the UV/S{sub 2}O{sub 8}{sup 2−} system. Mineralization of the β-lactams could be achieved at high UV fluence, with a slow formation of SO{sub 4}{sup 2−} and a much lower elimination of total organic carbon (TOC). The transformation mechanisms were also investigated showing the main reaction pathways of hydroxylation (+16 Da) at the aromatic ring and/or the sulfur atom, hydrolysis (+18 Da) at the β-lactam ring and decarboxylation (–44 Da) for the three penicillins. Oxidation of amine group was also observed for ampicillin. This study suggests that UV/H{sub 2}O{sub 2} and UV/S{sub 2}O{sub 8}{sup 2−} advanced

  17. Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H2O2 and Na2S2O8 under UV-254 nm irradiation

    International Nuclear Information System (INIS)

    He, Xuexiang; Mezyk, Stephen P.; Michael, Irene; Fatta-Kassinos, Despo; Dionysiou, Dionysios D.

    2014-01-01

    Graphical abstract: - Highlights: • Removal efficiency was comparable at different UV fluence rates but same fluence. • Reducing pH to 3 or 2 did not inhibit the removal of nitrobenzene by UV/S 2 O 8 2− . • 1.84 × 10 −14 M [HO • ] ss and 3.10 × 10 −13 M [SO 4 • − ] ss in UV/S 2 O 8 2− were estimated. • HO • reacted faster with the β-lactams than SO 4 • − but sharing similar byproducts. • Transformation pathways included hydroxylation, hydrolysis and decarboxylation. - Abstract: The extensive production and usage of antibiotics have led to an increasing occurrence of antibiotic residuals in various aquatic compartments, presenting a significant threat to both ecosystem and human health. This study investigated the degradation of selected β-lactam antibiotics (penicillins: ampicillin, penicillin V, and piperacillin; cephalosporin: cephalothin) by UV-254 nm activated H 2 O 2 and S 2 O 8 2− photochemical processes. The UV irradiation alone resulted in various degrees of direct photolysis of the antibiotics; while the addition of the oxidants improved significantly the removal efficiency. The steady-state radical concentrations were estimated, revealing a non-negligible contribution of hydroxyl radicals in the UV/S 2 O 8 2− system. Mineralization of the β-lactams could be achieved at high UV fluence, with a slow formation of SO 4 2− and a much lower elimination of total organic carbon (TOC). The transformation mechanisms were also investigated showing the main reaction pathways of hydroxylation (+16 Da) at the aromatic ring and/or the sulfur atom, hydrolysis (+18 Da) at the β-lactam ring and decarboxylation (–44 Da) for the three penicillins. Oxidation of amine group was also observed for ampicillin. This study suggests that UV/H 2 O 2 and UV/S 2 O 8 2− advanced oxidation processes (AOPs) are capable of degrading β-lactam antibiotics decreasing consequently the antibiotic activity of treated waters

  18. Antibiotic resistant pattern of methicillin resistant and sensitive Staphylococcus aureus isolated from patients durining 2009-2010, Ahvaz, Iran.

    Directory of Open Access Journals (Sweden)

    N Parhizgari

    2013-12-01

    Full Text Available Abstract Background & aim: Staphylococcus aureus is one of the most important nosocomial infecting agents resistant to commonly used antibiotics. Nowadays, methicillin-resistant S. aureus (MRSA is considered one of the main causes of nosocomial infections. The aim of this study was to identify the antibiotic resistance pattern of methicicllin- resistant and susceptible strains in Ahwaz, Iran. Methods: In the present cross - sectional study, a number of 255 clinically suspected cases of Staphylococcus aureus were collected during a 19 month period. The bacteria were investigated using standard biochemical tests such as catalase, mannitol fermentation, coagulase and Dnase. Sensitive strains were confirmed by disk diffusion method compared to commonly used antibiotics. The collected data were analyzed using descriptive statistical tests. Results: of 255 suspected cases, 180 were confirmed as S.aureus, a total of 59 strains of S. aureus (2/37 percent were resistant to methicillin. Resistance to S. aureus strains resistant to methicillin included: chloramphenicol (3.38%, rifampin (45.76%, norfloxacin (89.83%, gentamicin (89.83%, ciprofloxacin, (91.52%, azithromycin, (88.13%, cotrimoxazole (86.44% and all isolates strains were sensitive to vancomycin and nitrofurantoin. A total of 10 different patterns of antibiotic resistance in methicillin-resistant Staphylococcus aureus strains were identified. Conclusion: Expression of new resistance factor in nosocomial infection is one of the major challenges in treating these infections. This study showed a high prevalence of resistance against some class of antibiotics in MRSA isolated from Imam Khomeini and Golestan hospital of Ahwaz, Iran. Key words: Nosocomial infection, Methicillin Resistant Staphylococcus aureus (MRSA, Antibiotic Resistant Pattern

  19. Selection of antibiotic resistance at very low antibiotic concentrations

    OpenAIRE

    Sandegren, Linus

    2014-01-01

    Human use of antibiotics has driven the selective enrichment of pathogenic bacteria resistant to clinically used drugs. Traditionally, the selection of resistance has been considered to occur mainly at high, therapeutic levels of antibiotics, but we are now beginning to understand better the importance of selection of resistance at low levels of antibiotics. The concentration of an antibiotic varies in different body compartments during treatment, and low concentrations of antibiotics are fou...

  20. Antibiotic alternatives: the substitution of antibiotics in animal husbandry?

    OpenAIRE

    Cheng, Guyue; Hao, Haihong; Xie, Shuyu; Wang, Xu; Dai, Menghong; Huang, Lingli; Yuan, Zonghui

    2014-01-01

    It is a common practice for decades to use of sub-therapeutic dose of antibiotics in food-animal feeds to prevent animals from diseases and to improve production performance in modern animal husbandry. In the meantime, concerns over the increasing emergence of antibiotic-resistant bacteria due to the unreasonable use of antibiotics and an appearance of less novelty antibiotics have prompted efforts to develop so-called alternatives to antibiotics. Whether or not the alternatives could really ...

  1. Low-dose Norfloxacin-treated leptospires induce less IL-1β release in J774A.1 cells following discrepant leptospiral gene expression.

    Science.gov (United States)

    Cao, Yongguo; Xie, Xufeng; Zhang, Wenlong; Wu, Dianjun; Tu, Changchun

    2018-06-01

    Currently, accumulating evidence is challenging subtherapeutic therapy. Low-dose Norfloxacin (Nor) has been reported to suppress the immune response and worsen leptospirosis. In this study, we investigated the influence of low-dose Nor (0.03 μg/ml, 0.06 μg/ml, 0.125 μg/ml) on leptospiral gene expression and analyzed the immunomodulatory effects of low-dose Nor-treated leptospires in J774A.1 cells. To study the expression profiles of low-dose Nor-treated leptospires, we chose LipL71/LipL21 as reference genes determined by the geNorm applet in this experiment. The results showed that low-dose Nor up-regulated the expression of FlaB and inhibited the expression of 16S rRNA, LipL32, LipL41, Loa22, KdpA, and KdpB compared with the untreated leptospires. These results indicated that low-dose Nor could regulate leptospiral gene expression. Using RT-PCR, the gene expression of IL-1β and TNF-α in J774A.1 cells was detected. Nor-treated leptospires induced higher expression levels of both IL-1β and TNF-α. However, when analyzed by ELISA, the release of mature IL-1β was reduced compared with that observed in cells induced with no Nor-treated leptospires, although the TNF-α protein level showed no significant change. Our study indicated that the gene expression of leptospires could be modulated by low-dose Nor, which induced less IL-1β release in J774A.1 cells. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Enhanced photocatalytic degradation of norfloxacin in aqueous Bi{sub 2}WO{sub 6} dispersions containing nonionic surfactant under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Lin, E-mail: tanglin@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Wang, Jiajia [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zeng, Guangming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Liu, Yani; Deng, Yaocheng; Zhou, Yaoyu; Tang, Jing; Wang, Jingjing; Guo, Zhi [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

    2016-04-05

    Highlights: • TX100 strongly enhanced the adsorption and photodegradation of NOF in Bi{sub 2}WO{sub 6} dispersions under visible light irradiation (400–750 nm). • Cu{sup 2+} (10 mM) significantly suppressed the photocatalytic degradation of NOF. • FT-IR demonstrated that the NOF adsorbed on Bi{sub 2}WO{sub 6} was completely degraded. • Three possible photocatalytic degradation pathways of NOF were proposed, according to the HPLC/MS/MS analysis. - Abstract: Photocatalytic degradation is an alternative method to remove pharmaceutical compounds in water, however it is hard to achieve efficient rate because of the poor solubility of pharmaceutical compounds in water. This study investigated the photodegradation of norfloxacin in a nonionic surfactant Triton-X100 (TX100)/Bi{sub 2}WO{sub 6} dispersion under visible light irradiation (400–750 nm). It was found that the degradation of poorly soluble NOF can be strongly enhanced with the addition of TX100. TX100 was adsorbed strongly on Bi{sub 2}WO{sub 6} surface and accelerated NOF photodegradation at the critical micelle concentration (CMC = 0.25 mM). Higher TX100 concentration (>0.25 mM) lowered the degradation rate. In the presence of TX100, the degradation rate reached the maximum value when the pH value was 8.06. FTIR analyses demonstrated that the adsorbed NOF on the catalyst was completely degraded after 2 h irradiation. According to the intermediates identified by HPLC/MS/MS, three possible degradation pathways were proposed to include addition of hydroxyl radical to quinolone ring, elimination of piperazynilic ring in fluoroquinolone molecules, and replacement of F atoms on the aromatic ring by hydroxyl radicals.

  3. Antibiotic-Resistant Gonorrhea

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search the CDC Gonorrhea Note: Javascript is disabled or is not supported ... on Facebook Sexually Transmitted Diseases (STDs) Antibiotic-Resistant Gonorrhea Recommend on Facebook Tweet Share Compartir Low Resolution ...

  4. Glycopeptide antibiotic biosynthesis.

    Science.gov (United States)

    Yim, Grace; Thaker, Maulik N; Koteva, Kalinka; Wright, Gerard

    2014-01-01

    Glycopeptides such as vancomycin, teicoplanin and telavancin are essential for treating infections caused by Gram-positive bacteria. Unfortunately, the dwindled pipeline of new antibiotics into the market and the emergence of glycopeptide-resistant enterococci and other resistant bacteria are increasingly making effective antibiotic treatment difficult. We have now learned a great deal about how bacteria produce antibiotics. This information can be exploited to develop the next generation of antimicrobials. The biosynthesis of glycopeptides via nonribosomal peptide assembly and unusual amino acid synthesis, crosslinking and tailoring enzymes gives rise to intricate chemical structures that target the bacterial cell wall. This review seeks to describe recent advances in our understanding of both biosynthesis and resistance of these important antibiotics.

  5. Antibiotics for uncomplicated diverticulitis

    DEFF Research Database (Denmark)

    Shabanzadeh, Daniel M; Wille-Jørgensen, Peer

    2012-01-01

    Diverticulitis is an inflammatory complication to the very common condition diverticulosis. Uncomplicated diverticulitis has traditionally been treated with antibiotics with reference to the microbiology, extrapolation from trials on complicated intra-abdominal infections and clinical experience....

  6. Antibiotics for sore throat.

    Science.gov (United States)

    Spinks, Anneliese; Glasziou, Paul P; Del Mar, Chris B

    2013-11-05

    Sore throat is a common reason for people to present for medical care. Although it remits spontaneously, primary care doctors commonly prescribe antibiotics for it. To assess the benefits of antibiotics for sore throat for patients in primary care settings. We searched CENTRAL 2013, Issue 6, MEDLINE (January 1966 to July week 1, 2013) and EMBASE (January 1990 to July 2013). Randomised controlled trials (RCTs) or quasi-RCTs of antibiotics versus control assessing typical sore throat symptoms or complications. Two review authors independently screened studies for inclusion and extracted data. We resolved differences in opinion by discussion. We contacted trial authors from three studies for additional information. We included 27 trials with 12,835 cases of sore throat. We did not identify any new trials in this 2013 update. 1. Symptoms Throat soreness and fever were reduced by about half by using antibiotics. The greatest difference was seen at day three. The number needed to treat to benefit (NNTB) to prevent one sore throat at day three was less than six; at week one it was 21. 2. Non-suppurative complications The trend was antibiotics protecting against acute glomerulonephritis but there were too few cases to be sure. Several studies found antibiotics reduced acute rheumatic fever by more than two-thirds within one month (risk ratio (RR) 0.27; 95% confidence interval (CI) 0.12 to 0.60). 3. Suppurative complications Antibiotics reduced the incidence of acute otitis media within 14 days (RR 0.30; 95% CI 0.15 to 0.58); acute sinusitis within 14 days (RR 0.48; 95% CI 0.08 to 2.76); and quinsy within two months (RR 0.15; 95% CI 0.05 to 0.47) compared to those taking placebo. 4. Subgroup analyses of symptom reduction Antibiotics were more effective against symptoms at day three (RR 0.58; 95% CI 0.48 to 0.71) if throat swabs were positive for Streptococcus, compared to RR 0.78; 95% CI 0.63 to 0.97 if negative. Similarly at week one the RR was 0.29 (95% CI 0.12 to 0

  7. A non-polyene antifungal antibiotic from Streptomyces albidoflavus ...

    Indian Academy of Sciences (India)

    Out of these, 22% of the isolates exhibited activity against fungi. One promising strain, Streptomyces albidoflavus PU 23 with strong antifungal activity against pathogenic fungi was selected for further studies. Antibiotic was extracted and purified from the isolate. Aspergillus spp. was most sensitive to the antibiotic followed by ...

  8. Antibiotics produced by Streptomyces.

    Science.gov (United States)

    Procópio, Rudi Emerson de Lima; Silva, Ingrid Reis da; Martins, Mayra Kassawara; Azevedo, João Lúcio de; Araújo, Janete Magali de

    2012-01-01

    Streptomyces is a genus of Gram-positive bacteria that grows in various environments, and its shape resembles filamentous fungi. The morphological differentiation of Streptomyces involves the formation of a layer of hyphae that can differentiate into a chain of spores. The most interesting property of Streptomyces is the ability to produce bioactive secondary metabolites, such as antifungals, antivirals, antitumorals, anti-hypertensives, immunosuppressants, and especially antibiotics. The production of most antibiotics is species specific, and these secondary metabolites are important for Streptomyces species in order to compete with other microorganisms that come in contact, even within the same genre. Despite the success of the discovery of antibiotics, and advances in the techniques of their production, infectious diseases still remain the second leading cause of death worldwide, and bacterial infections cause approximately 17 million deaths annually, affecting mainly children and the elderly. Self-medication and overuse of antibiotics is another important factor that contributes to resistance, reducing the lifetime of the antibiotic, thus causing the constant need for research and development of new antibiotics. Copyright © 2012 Elsevier Editora Ltda. All rights reserved.

  9. Strategies to Minimize Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    Sang Hee Lee

    2013-09-01

    Full Text Available Antibiotic resistance can be reduced by using antibiotics prudently based on guidelines of antimicrobial stewardship programs (ASPs and various data such as pharmacokinetic (PK and pharmacodynamic (PD properties of antibiotics, diagnostic testing, antimicrobial susceptibility testing (AST, clinical response, and effects on the microbiota, as well as by new antibiotic developments. The controlled use of antibiotics in food animals is another cornerstone among efforts to reduce antibiotic resistance. All major resistance-control strategies recommend education for patients, children (e.g., through schools and day care, the public, and relevant healthcare professionals (e.g., primary-care physicians, pharmacists, and medical students regarding unique features of bacterial infections and antibiotics, prudent antibiotic prescribing as a positive construct, and personal hygiene (e.g., handwashing. The problem of antibiotic resistance can be minimized only by concerted efforts of all members of society for ensuring the continued efficiency of antibiotics.

  10. The ionising radiation effect on reactivation of antibiotics

    International Nuclear Information System (INIS)

    Dikij, I.L.; Manskij, A.A.; Krasnopyorova, A.P.

    2002-01-01

    The effect of gamma-radiation on the molecular structure of antibiotics was studied with a view to extending their useful life beyond the current expiration period. The following antibiotics were examined: penicillin, bicillin-3,5, streptomycine, and ampioxe. The samples were irradiated by Co-60 gamma-radiation from a research irradiator. Doses of 0.1, 1, 5, 7, and 10 Gy were applied. The processes were elucidated using the classical method of 2-divisible serial dilutions and IR-spectroscopy. All the measurements were carried out at 300 K. The IR-spectra revealed that the chemical structure of new and old antibiotics is identical; the change in the antibiotic activity is generally a result of deformation of the molecule or change in its conformation; the reactivation process returns the molecule to its previous state and the activity of antibiotic after reactivation meets established standards. Hence, this method can be used for the reactivation of expired antibiotics

  11. Beta-lactam antibiotic-induced platelet dysfunction: Evidence for irreversible inhibition of platelet activation in vitro and in vivo after prolonged exposure to penicillin

    International Nuclear Information System (INIS)

    Burroughs, S.F.; Johnson, G.J.

    1990-01-01

    beta-Lactam antibiotics cause platelet dysfunction with bleeding complications. Previous in vitro studies documented reversible inhibition of agonist-receptor interaction. This mechanism is inadequate to explain the effect of beta-lactam antibiotics in vivo. Platelet function does not return to normal immediately after drug treatment, implying irreversible inhibition of platelet function. We report here evidence of irreversible platelet functional and biochemical abnormalities after in vitro and in vivo exposure to beta-lactam antibiotics. Irreversible binding of [14C]-penicillin (Pen) occurred in vitro. After 24 hours' in vitro incubation with 10 to 20 mmol/L Pen, or ex vivo after antibiotic treatment, irreversible functional impairment occurred; but no irreversible inhibition of alpha 2 adrenergic receptors, measured with [3H]-yohimbine, or high-affinity thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors, measured with agonist [3H]-U46619 and antagonist [3H]-SQ29548, occurred. However, low-affinity platelet TXA2/PGH2 receptors were decreased 40% after Pen exposure in vitro or in vivo, indicating irreversible membrane alteration. Two postreceptor biochemical events were irreversibly inhibited in platelets incubated with Pen for 24 hours in vitro or ex vivo after antibiotic treatment. Thromboxane synthesis was inhibited 28.3% to 81.7%. Agonist-induced rises in cytosolic calcium ([Ca2+]i) were inhibited 40.1% to 67.5% in vitro and 26.6% to 52.2% ex vivo. Therefore, Pen binds to platelets after prolonged exposure, resulting in irreversible dysfunction attributable to inhibition of TXA2 synthesis and impairment of the rise in [Ca2+]i. The loss of low-affinity TXA2/PGH2 receptors suggests that the primary site of action of these drugs is on the platelet membrane

  12. Microfluidics for Antibiotic Susceptibility and Toxicity Testing

    Directory of Open Access Journals (Sweden)

    Jing Dai

    2016-10-01

    Full Text Available The recent emergence of antimicrobial resistance has become a major concern for worldwide policy makers as very few new antibiotics have been developed in the last twenty-five years. To prevent the death of millions of people worldwide, there is an urgent need for a cheap, fast and accurate set of tools and techniques that can help to discover and develop new antimicrobial drugs. In the past decade, microfluidic platforms have emerged as potential systems for conducting pharmacological studies. Recent studies have demonstrated that microfluidic platforms can perform rapid antibiotic susceptibility tests to evaluate antimicrobial drugs’ efficacy. In addition, the development of cell-on-a-chip and organ-on-a-chip platforms have enabled the early drug testing, providing more accurate insights into conventional cell cultures on the drug pharmacokinetics and toxicity, at the early and cheaper stage of drug development, i.e., prior to animal and human testing. In this review, we focus on the recent developments of microfluidic platforms for rapid antibiotics susceptibility testing, investigating bacterial persistence and non-growing but metabolically active (NGMA bacteria, evaluating antibiotic effectiveness on biofilms and combinatorial effect of antibiotics, as well as microfluidic platforms that can be used for in vitro antibiotic toxicity testing.

  13. Release of antibiotics from collagen dressing.

    Science.gov (United States)

    Grzybowski, J; Antos-Bielska, M; Ołdak, E; Trafny, E A

    1997-01-01

    Our new collagen dressing has been developed recently. Three types (A, B, and C) of the dressing were prepared in this study. Each type contained bacitracin, neomycin or colistin. The antibiotic was input into: i. collagen sponge (CS)--type A, ii. layer of limited hydrophobicity (LLH)--type B, and iii. into both CS and LLH layers--type C. The final concentration of the antibiotic that resulted from the loading level was 2 mg/cm2 for the dressings of type A and B and 4 mg/cm2 for the dressing of type C. The antibiotics were then extracted from the pieces of dressings for two days through dialysis membrane. Susceptibility of 54 bacterial strains (S. aureus, P. aeruginosa, and Acinetobacter) isolated from burn wounds were tested to the three antibiotics used for preparation of the dressings. The results of the study evidenced that efficiency of released of antibiotics into the extracts depended on the kind of antibiotic and on the type of dressing. The concentration of the antibiotics proved to be much higher than MIC90 values of the bacterial isolates tested in respect to their susceptibility. The dressing containing mixture of the three antibiotics in two layers--CS and LLH is now considered as potentially effective for care of infected wounds. It may be useful for the treatment of infected wounds or for profilaxis of contaminated wounds, ensuring: i. sufficient antimicrobial activity in wound, and ii. optimal wound environment for the presence of collagenic biomaterial on the damaged tissue.

  14. Pharmacodynamic evaluation of the activity of antibiotics against hemin- and menadione-dependent small-colony variants of Staphylococcus aureus in models of extracellular (broth) and intracellular (THP-1 monocytes) infections.

    Science.gov (United States)

    Garcia, L G; Lemaire, S; Kahl, B C; Becker, K; Proctor, R A; Denis, O; Tulkens, P M; Van Bambeke, F

    2012-07-01

    Staphylococcus aureus small-colony variants (SCVs) persist intracellularly, which may contribute to persistence/recurrence of infections and antibiotic failure. We have studied the intracellular fate of menD and hemB mutants (corresponding to menadione- and hemin-dependent SCVs, respectively) of the COL methicillin-resistant S. aureus (MRSA) strain and the antibiotic pharmacodynamic profile against extracellular (broth) and intracellular (human THP-1 monocytes) bacteria. Compared to the parental strain, SCVs showed slower extracellular growth (restored upon medium supplementation with menadione or hemin), reduced phagocytosis, and, for the menD SCV, lower intracellular counts at 24 h postinfection. Against extracellular bacteria, daptomycin, gentamicin, rifampin, moxifloxacin, and oritavancin showed similar profiles of activity against all strains, with a static effect obtained at concentrations close to their MICs and complete eradication as maximal effect. In contrast, vancomycin was not bactericidal against SCVs. Against intracellular bacteria, concentration-effect curves fitted sigmoidal regressions for vancomycin, daptomycin, gentamicin, and rifampin (with maximal effects lower than a 2-log decrease in CFU) but biphasic regressions (with a maximal effect greater than a 3-log decrease in CFU) for moxifloxacin and oritavancin, suggesting a dual mode of action against intracellular bacteria. For all antibiotics, these curves were indistinguishable between the strains investigated, except for the menD mutant, which systematically showed a lower amplitude of the concentration-effect response, with markedly reduced minimal efficacy (due to slower growth) but no change in maximal efficacy. The data therefore show that the maximal efficacies of antibiotics are similar against normal-phenotype and menadione- and hemin-dependent strains despite their different intracellular fates, with oritavancin, and to some extent moxifloxacin, being the most effective.

  15. Be Smart: Antibiotics Will Not Help a Cold or the Flu

    Science.gov (United States)

    ... Submit Search the CDC Get Smart: Know When Antibiotics Work in Doctor’s Offices Note: Javascript is disabled or ... for States National Activities Get Smart: Know When Antibiotics Work Strategies and Plans Related CDC Education Programs Global ...

  16. Determination of antibiotics in sewage from hospitals, nursery and slaughter house, wastewater treatment plant and source water in Chongqing region of Three Gorge Reservoir in China

    Energy Technology Data Exchange (ETDEWEB)

    Xiaosong, Chang [Department of Environmental Hygiene, School of Military Preventive Medicine, Third Military Medical University, Chongqing 400038 (China); Meyer, Michael T [United States Geological Survey, 4821 Quail Crest Place, Lawrence, Kansas 66049 (United States); Xiaoyun, Liu [Center for Disease Prevention and Control, Lanzhou Military Region, Lanzhou 730020 (China); Qing, Zhao; Hao, Chen; Jian, Chen; Zhiqun, Qiu; Lan, Yang [Department of Environmental Hygiene, School of Military Preventive Medicine, Third Military Medical University, Chongqing 400038 (China); Jia, Cao [Department of Military Toxicology, School of Military Preventive Medicine, Third Military Medical University, Chongqing 400038 (China); Shu Weiqun, E-mail: xm0630@sina.co [Department of Environmental Hygiene, School of Military Preventive Medicine, Third Military Medical University, Chongqing 400038 (China)

    2010-05-15

    Sewage samples from 4 hospitals, 1 nursery, 1 slaughter house, 1 wastewater treatment plant and 5 source water samples of Chongqing region of Three Gorge Reservoir were analyzed for macrolide, lincosamide, trimethoprim, fluorouinolone, sulfonamide and tetracycline antibiotics by online solid-phase extraction and liquid chromatography-tandem mass spectrometry. Results showed that the concentration of ofloxacin (OFX) in hospital was the highest among all water environments ranged from 1.660 mug/L to 4.240 mug/L and norfloxacin (NOR, 0.136-1.620 mug/L), ciproflaxacin (CIP, ranged from 0.011 mug/L to 0.136 mug/L), trimethoprim (TMP, 0.061-0.174 mug/L) were commonly detected. Removal range of antibiotics in the wastewater treatment plant was 18-100% and the removal ratio of tylosin, oxytetracycline and tetracycline were 100%. Relatively higher removal efficiencies were observed for tylosin (TYL), oxytetracycline (OXY) and tetracycline (TET)(100%), while lower removal efficiencies were observed for Trimethoprim (TMP, 1%), Epi-iso-chlorotetracycline (EICIC, 18%) and Erythromycin-H{sub 2}O (ERY-H{sub 2}O, 24%). Antibiotics were removed more efficiently in primary treatment compared with those in secondary treatment. - This study give the first insight into the concentration of antibiotics in receiving waters from 4 hospitals, 1 nursery, 1 slaughter house, 1 wastewater treatment plant and 5 source water of Chongqing region of Three Gorge Reservoir

  17. Determination of antibiotics in sewage from hospitals, nursery and slaughter house, wastewater treatment plant and source water in Chongqing region of Three Gorge Reservoir in China

    International Nuclear Information System (INIS)

    Chang Xiaosong; Meyer, Michael T.; Liu Xiaoyun; Zhao Qing; Chen Hao; Chen Jian; Qiu Zhiqun; Yang Lan; Cao Jia; Shu Weiqun

    2010-01-01

    Sewage samples from 4 hospitals, 1 nursery, 1 slaughter house, 1 wastewater treatment plant and 5 source water samples of Chongqing region of Three Gorge Reservoir were analyzed for macrolide, lincosamide, trimethoprim, fluorouinolone, sulfonamide and tetracycline antibiotics by online solid-phase extraction and liquid chromatography-tandem mass spectrometry. Results showed that the concentration of ofloxacin (OFX) in hospital was the highest among all water environments ranged from 1.660 μg/L to 4.240 μg/L and norfloxacin (NOR, 0.136-1.620 μg/L), ciproflaxacin (CIP, ranged from 0.011 μg/L to 0.136 μg/L), trimethoprim (TMP, 0.061-0.174 μg/L) were commonly detected. Removal range of antibiotics in the wastewater treatment plant was 18-100% and the removal ratio of tylosin, oxytetracycline and tetracycline were 100%. Relatively higher removal efficiencies were observed for tylosin (TYL), oxytetracycline (OXY) and tetracycline (TET)(100%), while lower removal efficiencies were observed for Trimethoprim (TMP, 1%), Epi-iso-chlorotetracycline (EICIC, 18%) and Erythromycin-H 2 O (ERY-H 2 O, 24%). Antibiotics were removed more efficiently in primary treatment compared with those in secondary treatment. - This study give the first insight into the concentration of antibiotics in receiving waters from 4 hospitals, 1 nursery, 1 slaughter house, 1 wastewater treatment plant and 5 source water of Chongqing region of Three Gorge Reservoir

  18. Bakery by-products based feeds borne-Saccharomyces cerevisiae strains with probiotic and antimycotoxin effects plus antibiotic resistance properties for use in animal production.

    Science.gov (United States)

    Poloni, Valeria; Salvato, Lauranne; Pereyra, Carina; Oliveira, Aguida; Rosa, Carlos; Cavaglieri, Lilia; Keller, Kelly Moura

    2017-09-01

    The aim of this study was to select S. cerevisiae strains able to exert probiotic and antimycotoxin effects plus antibiotics resistance properties for use in animal production. S. cerevisiae LL74 and S. cerevisiae LL83 were isolated from bakery by-products intended for use in animal feed and examined for phenotypic characteristics and nutritional profile. Resistance to antibiotic, tolerance to gastrointestinal conditions, autoaggregation and coaggregation assay, antagonism to animal pathogens and aflatoxin B 1 binding were studied. S. cerevisiae LL74 and S. cerevisiae LL83 showed resistance to all the antibiotics assayed (ampicillin, streptomycin, neomycin, norfloxacin, penicillin G, sulfonamide and trimethoprim). The analysis showed that exposure time to acid pH had a significant impact onto the viable cell counts onto both yeast strains. Presence of bile 0.5% increased significantly the growth of the both yeast strains. Moreover, they were able to tolerate the simulated gastrointestinal conditions assayed. In general, the coaggregation was positive whereas the autoaggregation capacity was not observed. Both strains were able to adsorb AFB 1 . In conclusion, selected S. cerevisiae LL74 and S. cerevisiae LL83 have potential application to be used as a biological method in animal feed as antibiotic therapy replacement in, reducing the adverse effects of AFB 1 and giving probiotic properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The multifaceted roles of antibiotics and antibiotic resistance in nature

    Directory of Open Access Journals (Sweden)

    Saswati eSengupta

    2013-03-01

    Full Text Available Antibiotics are chemotherapeutic agents, which have been a very powerful tool in the clinical management of bacterial diseases since the 1940s. However, benefits offered by these magic bullets have been substantially lost in subsequent days following the widespread emergence and dissemination of antibiotic resistant strains. While it is obvious that excessive and imprudent use of antibiotics significantly contributes to the emergence of resistant strains, antibiotic-resistance is also observed in natural bacteria of remote places unlikely to be impacted by human intervention. Both antibiotic biosynthetic genes and resistance-conferring genes have been known to evolve billions of years ago, long before clinical use of antibiotics. Hence it appears that antibiotics and antibiotics resistance determinants have some other roles in nature, which often elude our attention because of overemphasis on the therapeutic importance of antibiotics and the crisis imposed by the antibiotic-resistance in pathogens. In the natural milieu, antibiotics are often found to be present in subinhibitory concentrations acting as signalling molecules supporting quorum sensing and biofilm formation. They also play an important role in the production of virulence factors and influence host-parasite interactions (e.g., phagocytosis, adherence to the target cell and so on. The evolutionary and ecological aspects of antibiotics and antibiotic-resistance in the naturally occurring microbial community are little understood. Therefore, the actual role of antibiotics in nature warrants in-depth investigations. Studies on such an intriguing behaviour of the microorganisms promise insight into the intricacies of the microbial physiology and are likely to provide some lead in controlling the emergence and subsequent dissemination of antibiotic resistance. This article highlights some of the recent findings on the role of antibiotics and genes that confer resistance to antibiotics in

  20. Antibiotics in the clinical pipeline in 2013.

    Science.gov (United States)

    Butler, Mark S; Blaskovich, Mark A; Cooper, Matthew A

    2013-10-01

    The continued emergence of multi-drug-resistant bacteria is a major public health concern. The identification and development of new antibiotics, especially those with new modes of action, is imperative to help treat these infections. This review lists the 22 new antibiotics launched since 2000 and details the two first-in-class antibiotics, fidaxomicin (1) and bedaquiline (2), launched in 2011 and 2012, respectively. The development status, mode of action, spectra of activity, historical discovery and origin of the drug pharmacophore (natural product, natural product derived, synthetic or protein/mammalian peptide) of the 49 compounds and 6 β-lactamase/β-lactam combinations in act